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Sample records for direct chill casting

  1. Centerline Depletion in Direct-Chill Cast Aluminum Alloys: The Avalanche Effect and Its Consequence for Turbulent Jet Casting

    NASA Astrophysics Data System (ADS)

    Wagstaff, Samuel R.; Allanore, Antoine

    2016-10-01

    Avalanche dynamics of sedimenting grains in direct-chill casting of aluminum ingots is investigated as a primary driving force for centerline segregation. An analytical model predicting the importance of avalanche events as a function of casting parameters is proposed and validated with prior art results. New experimental results investigating the transient and steady-state centerline segregation of DC casting with a turbulent jet are reported.

  2. Centerline Depletion in Direct-Chill Cast Aluminum Alloys: The Avalanche Effect and Its Consequence for Turbulent Jet Casting

    NASA Astrophysics Data System (ADS)

    Wagstaff, Samuel R.; Allanore, Antoine

    2016-07-01

    Avalanche dynamics of sedimenting grains in direct-chill casting of aluminum ingots is investigated as a primary driving force for centerline segregation. An analytical model predicting the importance of avalanche events as a function of casting parameters is proposed and validated with prior art results. New experimental results investigating the transient and steady-state centerline segregation of DC casting with a turbulent jet are reported.

  3. Microstructure and fatigue characteristics of direct chill cast and electromagnetic cast 2024 Al alloy ingots

    NASA Astrophysics Data System (ADS)

    Kim, Sug Won; Hao, Hai

    2003-07-01

    The distinct advantages of the electromagnetic casting (EMC) process consist in the presence of stirring motions in the melt, which lead to significant grain size reduction in solidified ingot. Furthermore, surface and subsurface qualities are improved due to the absence of ingot mold. However, it is impossible to achieve the aforementioned advantages in conventional direct chill casting (DCC). In order to contrast the before and after heat treatments of the microstructural and mechanical characteristics of EMC and DCC 2024 aluminium alloys, optical microscopy, scanning electron microscopy, transmission electron microscopy (TEM), X-ray diffractions (XRD), differential scanning calorimetry (DSC), etc. were carried out. Compared with the DCC ingot, the EMC ingot has better mechanical properties not only in the ascast condition but also in the as-aged condition. The DSC curves show that the EMC specimens have high enthalpy, i.e., the thermal kinetic energy to form precipitates during the aging treatment process. Despite heat treatments applied to the DCC ingot, it fails to attain the same mechanical properties as the EMC ingot. Moreover, considering the expernsive scalping operation for DCC ingots, the EMC technique, which offers a lower manufacturing cost, is one of the best manufacturing methods used in obtaining the ingots of wrought aluminum alloys.

  4. Simulation Study of Al-1Mn/Al-10Si Circular Clad Ingots Prepared by Direct Chill Casting

    NASA Astrophysics Data System (ADS)

    Wu, Li; Kang, Huijun; Chen, Zongning; Fu, Ying; Wang, Tongmin

    2016-02-01

    A modified direct chill casting process based on Novelis FusionTM Technology co-casting process was used recently to prepare Al-1Mn/Al-10Si circular clad ingots. In the current study, a comprehensive simulation model was developed to investigate the direct chill casting process for preparing the Al-1Mn/Al-10Si circular clad ingots, and a parametric study and experimental research of the direct chill casting process was conducted to explore potential success and failure casting conditions. The simulation results revealed the bonding mechanism of the Al-1Mn/Al-10Si interface in the direct chill casting process and identified the effect of certain parameters on casting performance. The results indicated that the effect of casting speed and Al-1Mn casting temperature on the variations of the minimum solid fraction of Al-1Mn at the interface is stronger than that of cooling water flow rate in inner mold, while Al-10Si casting temperature is the weakest of the four casting parameters. The corresponding experimental results verified that Al-1Mn/Al-10Si circular clad ingot with acceptable metallurgical bonding can be successfully prepared by direct chill casting process under the proper casting parameters. The thickness of diffusion zone is about 40 μm, and the fractured position in tensile test was located in the Al-1Mn alloy side which indicated the strength of the interfacial region is higher than that of Al-1Mn alloy.

  5. Macrosegregation in aluminum alloy ingot cast by the semicontinuous direct chill method

    NASA Technical Reports Server (NTRS)

    Yu, H.; Granger, D. A.

    1984-01-01

    A theoretical model of the semicontinuous DC casting method is developed to predict the positive segregation observed at the subsurface and the negative segregation commonly found at the center of large commercial-size aluminum alloy ingot. Qualitative analysis of commercial-size aluminum alloy semicontinuous cast direct chill (DC) ingot is carried out. In the analysis, both positive segregation in the ingot subsurface and negative segregation at the center of the ingot are examined. Ingot subsurface macrosegregation is investigated by considering steady state casting of a circular cross-section binary alloy ingot. Nonequilibrium solidification is assumed with no solid diffusion, constant equilibrium partition ratio, and constant solid density.

  6. Coolant Characteristics and Control in Direct Chill Casting

    SciTech Connect

    2001-10-01

    This project focuses on understanding the fundamentals of coolant behavior and developing strategies to control the cooling rate of DC casting of aluminum ingots. Project partners will conduct a fundamental study to identify various parameters affecting critical heat flux and boiling transition and evaluate the effects of various additives (impurity particulates, sodium and calcium salts, carbonates, bicarbonates, surfactants, etc.).

  7. A computational study of low-head direct chill slab casting of aluminum alloy AA2024

    NASA Astrophysics Data System (ADS)

    Hasan, Mainul; Begum, Latifa

    2016-04-01

    The steady state casting of an industrial-sized AA2024 slab has been modeled for a vertical low-head direct chill caster. The previously verified 3-D CFD code is used to investigate the solidification phenomena of the said long-range alloy by varying the pouring temperature, casting speed and the metal-mold contact heat transfer coefficient from 654 to 702 °C, 60-180 mm/min, and 1.0-4.0 kW/(m2 K), respectively. The important predicted results are presented and thoroughly discussed.

  8. Characterisation and modelling of defect formation in direct-chill cast AZ80 alloy

    SciTech Connect

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

    2015-06-15

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

  9. Validation of Predicted Residual Stresses within Direct Chill Cast Magnesium Alloy Slab

    NASA Astrophysics Data System (ADS)

    Turski, Mark; Paradowska, Anna; Zhang, Shu-Yan; Mortensen, Dag; Fjaer, Hallvard; Grandfield, John; Davis, Bruce; DeLorme, Rick

    2012-05-01

    A significant level of cold cracking has been observed within direct chill (DC) cast, high-strength magnesium alloy Elektron WE43. These cracks have been attributed to the formation of significant residual stresses during casting. A finite-element modeling (FEM) code, which is called ALSIM, has been used to predict the residual stress within the DC-cast slab. Verification of the predicted residual stress field within an 870 × 315-mm sized slab has been carried out using neutron diffraction measurements. Given that measurements in such large-scale components using diffraction measurements are particularly challenging and expensive, the efficient use of neutron diffraction measurements is emphasized. This has included the use of sectioning, allowing the residual stress within the slab to be mapped in detail.

  10. Influence of Melt Feeding Scheme and Casting Parameters During Direct-Chill Casting on Microstructure of an AA7050 Billet

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    Direct-chill (DC) casting billets of an AA7050 alloy produced with different melt feeding schemes and casting speeds were examined in order to reveal the effect of these factors on the evolution of microstructure. Experimental results show that grain size is strongly influenced by the casting speed. In addition, the distribution of grain sizes across the billet diameter is mostly determined by melt feeding scheme. Grains tend to coarsen towards the center of a billet cast with the semi-horizontal melt feeding, while upon vertical melt feeding the minimum grain size was observed in the center of the billet. Computer simulations were preformed to reveal sump profiles and flow patterns during casting under different melt feeding schemes and casting speeds. The results show that solidification front and velocity distribution of the melt in the liquid and slurry zones are very different under different melt feeding scheme. The final grain structure and the grain size distribution in a DC casting billet is a result of a combination of fragmentation effects in the slurry zone and the cooling rate in the solidification range.

  11. Microstructure, Macrosegregation, and Thermal Analysis of Direct Chill Cast AA5182 Aluminum Alloy

    NASA Astrophysics Data System (ADS)

    Jamaly, N.; Haghdadi, N.; Phillion, A. B.

    2015-05-01

    The variation in microstructure, macrosegregation, and solidification behavior during aluminum alloy Direct Chill casting is investigated with respect to geometry. Optical microscopy, energy-dispersive analysis, and differential scanning calorimetry were employed to study the grain size evolution, distribution of alloying elements, and solidification sequence across the cross section of DC cast AA5182 aluminum alloy. The results show that (1) grain size increases from the surface to center of the ingot, corresponding to a decrease in the heat extraction rate; (2) there is a considerable macrosegregation of Mg, Mn, and Cr, with Mg showing negative segregation at the center and positive segregation at the surface, Mn showing negative segregation both at center and surface and positive segregation elsewhere, and Cr showing positive segregation at the center and negative segregation at the surface; (3) the solidus and the reaction temperatures vary as a function of position due to the local chemical composition and cooling rate. These findings, which show the interconnectivity of grain size, segregation, and solidification sequence, are useful in further analysis of the DC casting process and in predicting casting-related defects, specifically hot tear formation.

  12. Study on Fabrication of AA4032/AA6069 Cladding Billet Using Direct Chill Casting Process

    NASA Astrophysics Data System (ADS)

    Han, Xing; Zhang, Haitao; Shao, Bo; Li, Lei; Liu, Xuan; Cui, Jianzhong

    2016-04-01

    AA4032/AA6069 cladding billet in size of φ130 mm/φ110 mm was prepared by the modified direct chill casting process, and the parametric effect on casting performance was investigated using numerical simulation. Microstructures, elements distribution, and mechanical properties of the bonding interface were examined. The results show that metallurgical bonding interface can be obtained with the optimal parameters: the casting speed of 130 to 140 mm/min, the internal liquid level height of 50 to 60 mm, and the contact height of 40 to 50 mm. The metallurgical bonding interface is free of any discontinuities due to the fact that the alloying elements diffused across the interface and formed Ni-containing phase. Tensile strength of the cladding billet reaches 225.3 MPa, and the fracture position was located in AA6069 side, suggesting that the interface bonding strength is higher than the strength of AA6069. The interfacial shearing strength is 159.3 MPa, indicating excellent metallurgical bonding.

  13. A Numerical Study of the Direct-Chill Co-Casting of Aluminum Ingots via Fusion™ Technology

    NASA Astrophysics Data System (ADS)

    Baserinia, Amir R.; Caron, Etienne J. F. R.; Wells, Mary A.; Weckman, David C.; Barker, Simon; Gallerneault, Mark

    2013-08-01

    For the last 70 years, direct-chill (DC) casting has been the mainstay of the aluminum industry for the production of monolithic sheet and extruded products. Traditionally, clad aluminum sheet products have been made from separate core and clad DC cast ingots by an expensive roll-bonding process; however, in 2005, Novelis unveiled an innovative variant of the DC casting process called the Fusion™ Technology process that allows the production of multialloy ingots that can be rolled directly into laminated or clad sheet products. Of paramount importance for the successful commercialization of this new technology is a scientific and quantitative understanding of the Fusion™ casting process that will facilitate process optimization and aid in the future development of casting methodology for different alloy combinations and ingot and clad dimensions. In the current study, a numerical steady-state thermofluids model of the Fusion™ Technology casting process was developed and used to simulate the casting of rectangular bimetallic ingots made from the typical brazing sheet combination of AA3003 core clad with an AA4045 aluminum alloy. The analysis is followed by a parametric study of the process. The influence of casting speed and chill-bar height on the steady-state thermal field within the ingot is investigated. According to the criteria developed with the thermofluids model, the AA3003/AA4045 combination of aluminum alloys can be cast successfully with casting speeds up to 2.4 mm s-1. The quality of the metallurgical bond between the core and the clad is decreased for low casting speeds and chill-bar heights >35 mm. These results can be used as a guideline for improving the productivity of the Fusion™ Technology process.

  14. Modeling of ingot distortions during direct chill casting of aluminum alloys

    NASA Astrophysics Data System (ADS)

    Drezet, J.-M.; Rappaz, M.

    1996-10-01

    A comprehensive three-dimensional (3-D) mathematical model based upon the ABAQUS software has been developed for the computation of the thermomechanical state of the solidifying strand during direct chill (DC) casting of rolling sheet ingots and during subsequent cooling. Based upon a finiteelement formulation, the model determines the temperature distribution, the stresses, and the associated deformations in the metal. For that purpose, the thermomechanical properties of the alloy have been measured up to the coherency temperature using creep and indentation tests. The thermophysical properties as well as the boundary conditions associated with the lateral water spray have been determined using inverse modeling. The predicted ingot distortions, mainly, “butt curl,” “butt swell,” and lateral faces pull-in, are compared with experimental measurements performed during solidification and after complete cooling of the ingot. Particular emphasis is placed on the nonuniform contraction of the lateral faces. The influence of the mold shape and the contributions to this contraction are assessed as a function of the casting conditions.

  15. On Vertical Drag Defects Formation During Direct Chill (DC) Casting of Aluminum Billets

    NASA Astrophysics Data System (ADS)

    Carlberg, Torbjörn; Jarfors, Anders E. W.

    2013-12-01

    During air-slip direct chill casting of aluminum billets, one of the major defects occurring includes traces along the billet called vertical drags (VDs). If the VDs are too deep or too many, then they cause scraping of the billets. As in the subsequent extrusion process, the surface quality is known to impair both the productivity and quality of the profiles. In cast-house practice, many theories circulate about the causes of VD defects and how to avoid them, but in the literature, no thorough treatments have been made to explain this phenomenon. In the current study, the outer appearance, structure around, and compositions at the defects are analyzed. A theory for the formation of the defects, their cause, and how their appearance is coupled to different alloy types is presented. The segregation in the vicinity of the defects is discussed based on deformation of semisolid materials and coupled to Reynolds dilatancy in granular materials. The theory can explain differences between 6063 and 6005 alloys.

  16. Modeling and Optimization of Direct Chill Casting to Reduce Ingot Cracking

    SciTech Connect

    Das, S.K.; Ningileri, S.; Long, Z.; Saito, K.; Khraisheh, M.; Hassan, M.H.; Kuwana, K.; Han, Q.; Viswanathan, S.; Sabau, A.S.; Clark, J.; Hyrn, J.

    2006-08-15

    Approximately 68% of the aluminum produced in the United States is first cast into ingots prior to further processing into sheet, plate, extrusions, or foil. The direct chill (DC) semi-continuous casting process has been the mainstay of the aluminum industry for the production of ingots due largely to its robust nature and relative simplicity. Though the basic process of DC casting is in principle straightforward, the interaction of process parameters with heat extraction, microstructural evolution, and development of solidification stresses is too complex to analyze by intuition or practical experience. One issue in DC casting is the formation of stress cracks [1-15]. In particular, the move toward larger ingot cross-sections, the use of higher casting speeds, and an ever-increasing array of mold technologies have increased industry efficiencies but have made it more difficult to predict the occurrence of stress crack defects. The Aluminum Industry Technology Roadmap [16] has recognized the challenges inherent in the DC casting process and the control of stress cracks and selected the development of 'fundamental information on solidification of alloys to predict microstructure, surface properties, and stresses and strains' as a high-priority research need, and the 'lack of understanding of mechanisms of cracking as a function of alloy' and 'insufficient understanding of the aluminum solidification process', which is 'difficult to model', as technology barriers in aluminum casting processes. The goal of this Aluminum Industry of the Future (IOF) project was to assist the aluminum industry in reducing the incidence of stress cracks from the current level of 5% to 2%. Decreasing stress crack incidence is important for improving product quality and consistency as well as for saving resources and energy, since considerable amounts of cast metal could be saved by eliminating ingot cracking, by reducing the scalping thickness of the ingot before rolling, and by

  17. Modeling and Optimization of Direct Chill Casting to Reduce Ingot Cracking

    SciTech Connect

    Das, Subodh K.

    2006-01-09

    A successful four-year project on the modeling and optimization of direct chill (DC) casting to reduce ingot cracking has been completed. The project involved close collaboration among private industries, national laboratories, and universities. During the four-year project, 16 quarterly meetings brought the industrial partners and the research team together for discussion of research results and research direction. The industrial partners provided guidance, facilities, and experience to the research team. The research team went to two industrial plants to measure temperature distributions in commercial 60,000-lb DC casting ingot. The collaborative research resulted in several major accomplishments or findings: (1) Surface cracks were shown to be a result of hot tearing rather than cold cracks, as was thought before this project. These cracks form on the surface of a DC cast ingot just above the impingement point of the secondary cooling water jets. The cracks form along dendrite and grain boundaries, where solute and impurity elements are highly segregated. This understanding led to the development of a new technique for determining the mechanical properties in the nonequilibrium mushy zone of alloys and to thermodynamic predictions of the hot tearing propensity of DC cast ingots. (2) The apparent heat transfer coefficient (HTC) at the ingot surface in the water cooling region during DC casting was determined on the basis of temperature measurements in commercial DC casting ingots and an inverse heat transfer analysis. HTCs were calculated as a function of temperature and time, and covered the different regimes of heat transfer expected during DC casting. The calculated values were extrapolated to include the effect of water flow rate. The calculated HTCs had a peak at around 200 C, corresponding to the high heat transfer rates during nucleate boiling, and the profile was consistent with similar data published in the literature. (3) A new method, termed the

  18. Application of a Pore Fraction Hot Tearing Model to Directionally Solidified and Direct Chill Cast Aluminum Alloys

    NASA Astrophysics Data System (ADS)

    Dou, Ruifeng; Phillion, A. B.

    2016-08-01

    Hot tearing susceptibility is commonly assessed using a pressure drop equation in the mushy zone that includes the effects of both tensile deformation perpendicular to the thermal gradient as well as shrinkage feeding. In this study, a Pore Fraction hot tearing model, recently developed by Monroe and Beckermann (JOM 66:1439-1445, 2014), is extended to additionally include the effect of strain rate parallel to the thermal gradient. The deformation and shrinkage pore fractions are obtained on the basis of the dimensionless Niyama criterion and a scaling variable method. First, the model is applied to the binary Al-Cu system under conditions of directional solidification. It is shown that for the same Niyama criterion, a decrease in the cooling rate increases both the deformation and shrinkage pore fractions because of an increase in the time spent in the brittle temperature region. Second, the model is applied to the industrial aluminum alloy AA5182 as part of a finite element simulation of the Direct Chill (DC) casting process. It is shown that an increase in the casting speed during DC casting increases the deformation and shrinkage pore fractions, causing the maximum point of pore fraction to move towards the base of the casting. These results demonstrate that including the strain rate parallel to the thermal gradient significantly improves the predictive quality of hot tearing criteria based on the pressure drop equation.

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

    NASA Astrophysics Data System (ADS)

    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.

  20. Surface Structure Formation in Direct Chill (DC) Casting of Al Alloys

    NASA Astrophysics Data System (ADS)

    Bayat, Nazlin; Carlberg, Torbjörn

    2014-05-01

    The aim of this study is to increase the understanding of the surface zone formation during direct chill (DC) casting of aluminum billets produced by the air slip technology. The depth of the shell zone, with compositions deviating from the bulk, is of large importance for the subsequent extrusion productivity and quality of final products. The surface microstructures of 6060 and 6005 aluminum alloys in three different surface appearances—defect free, wavy surface, and spot defects—were studied. The surface microstructures and outer appearance, segregation depth, and phase formation were investigated for the mentioned cases. The results were discussed and explained based on the exudation of liquid metal through the mushy zone and the fact that the exudated liquid is contained within a surface oxide skin. Outward solidification in the surface layer was quantitatively analyzed, and the oxide skin movements explained meniscus line formation. Phases forming at different positions in the segregation zone were analyzed and coupled to a cellular solidification in the exudated layer.

  1. Structural Homogeneity of Direct-Chill Cast Ingots of Aluminum Alloy EN AW-5083

    NASA Astrophysics Data System (ADS)

    Dolić, Natalija; Markotić, Ante; Unkić, Faruk

    2007-06-01

    Structural homogeneity of direct-chill (DC) cast ingots of aluminum alloy EN AW-5083 was investigated in terms of grain size and grain distribution using the Latin square experimental design. The ingot cross-sectional homogeneity, the grain sizes, and the mean grain number per unit area were determined at precise, statistically defined locations in the slice by means of a semiautomatic method for measuring mean lineal intercept lengths. Based on the analysis of the differences in the number and distribution of grains between the slices cut from the ingot front and those from its rear, a general assessment of the ingot structural homogeneity was made. Analysis of variance showed the highly significant differences, in grain number in specimens taken from the ingot front section to be related to slice height/ingot depth and in those taken from the ingot rear section to individual charges and slice height. The grand means of the mean number of grains per unit area for the ingot front and rear sections show relatively high values with respect to ingot size. The obtained correlation coefficient, which suggests a good agreement between the number and distribution of grains at the ingot front and those at its rear, is indicative of good structural homogeneity of the ingot in general.

  2. A multiphysics and multiscale model for low frequency electromagnetic direct-chill casting

    NASA Astrophysics Data System (ADS)

    Košnik, N.; Guštin, A. Z.; Mavrič, B.; Šarler, B.

    2016-03-01

    Simulation and control of macrosegregation, deformation and grain size in low frequency electromagnetic (EM) direct-chill casting (LFEMC) is important for downstream processing. Respectively, a multiphysics and multiscale model is developed for solution of Lorentz force, temperature, velocity, concentration, deformation and grain structure of LFEMC processed aluminum alloys, with focus on axisymmetric billets. The mixture equations with lever rule, linearized phase diagram, and stationary thermoelastic solid phase are assumed, together with EM induction equation for the field imposed by the coil. Explicit diffuse approximate meshless solution procedure [1] is used for solving the EM field, and the explicit local radial basis function collocation method [2] is used for solving the coupled transport phenomena and thermomechanics fields. Pressure-velocity coupling is performed by the fractional step method [3]. The point automata method with modified KGT model is used to estimate the grain structure [4] in a post-processing mode. Thermal, mechanical, EM and grain structure outcomes of the model are demonstrated. A systematic study of the complicated influences of the process parameters can be investigated by the model, including intensity and frequency of the electromagnetic field. The meshless solution framework, with the implemented simplest physical models, will be further extended by including more sophisticated microsegregation and grain structure models, as well as a more realistic solid and solid-liquid phase rheology.

  3. Differences in microstructure and texture of Al-Mg sheets produced by twin-roll continuous casting and by direct-chill casting

    SciTech Connect

    Slamova, M.; Karlik, M.; Robaut, F.; Slama, P.; Veron, M

    2002-10-15

    Over the last two decades, the use of aluminum sheets in automotive applications has increased. Aluminum sheets are currently produced from direct-chill (DC) cast plates. The need for low-cost aluminum sheets is a challenge for the development of new materials produced by twin-roll continuous (TRC) casting and cold rolling. It is expected that the sheets produced from these different casting procedures can differ in their microstructure. Therefore, they can exhibit different formability behavior. The paper presents the results of the microstructural characterization and texture evaluation of aluminum sheets produced by both technologies. Sheets produced from twin-roll cast materials have much finer and more numerous second-phase particles, the grain structures of both types of materials are similar. Electron backscatter diffraction (EBSD) and X-ray diffraction techniques were used for texture evaluation and both confirmed the presence of stronger cube texture in the strips produced from DC-cast plates.

  4. Effect of electromagnetic vibration on the microstructure of direct chill cast Al-Zn-Mg-Cu alloy

    NASA Astrophysics Data System (ADS)

    Zuo, Y.; Fu, X.; Zhu, Q.; Li, L.; Wang, P.; Cui, J.

    2016-03-01

    An electromagnetic vibration was achieved by the combined application of an alternating magnetic field and a stationary magnetic field during direct chill (DC) casting process. The ingots with 200 mm in diameter were prepared under the influence of electromagnetic vibration. The effect of electromagnetic vibration on the microstructure of an Al-Zn-Mg-Cu alloy was studied. The results showed that electromagnetic vibration has a significant effect on the solidification behaviour, under the influence of electromagnetic vibration during DC casting process, the microstructure is significantly refined and the uniformity of microstructure is evidently improved. This paper introduces the DC casting technology with the application of electromagnetic vibration, presents these results and gives corresponding discussions.

  5. Modeling of metal delivery systems used in electromagnetic and direct-chill semicontinuous casting of aluminum

    NASA Astrophysics Data System (ADS)

    Jones, William Kinzy, Jr.

    1999-11-01

    The flow of liquid metal in the upper region of an EM (electromagnetic) or DC (direct chill) caster significantly contributes to the solidification behavior and subsequently the final ingot properties (e.g., average grain size and macrosegregation). The characterization of such a flow is a complicated task due to the high operating temperatures and the inherent opacity of the metal. However, as the demand for improved quality and reduced operational costs continues, understanding the mechanics of the flow becomes increasingly important. Hazardous, and often catastrophic, casting defects, such as hot cracks and tears, have been linked to non-uniformities in the solidification front that occur due to improper flow in the liquid pool. A novel technique to measure the flow, using particle imaging velocimetry (PIV), has been incorporated into a laboratory scale physical model of an aluminum caster. The instantaneous vector plots reveal valuable information regarding the turbulent nature and the intrinsic flow oscillations. However, time-averaged vector plots (TAV), obtained by ensemble averaging instantaneous plots, detail information regarding the average features of the flow. The results show that the method of metal delivery into the ingot significantly effected the flow patterns observed. Computational studies of the model geometry reproduce the same flow profiles adding to the validity of the PIV method. Based on the information obtained through physical modeling, an experimental campaign, on production size ingots, was conducted to determine the influence of the liquid pool velocities on the sump profile. Furthermore, a 3D coupled fluid flow-solidification finite element model was developed as a tool to predict the fluid flow/solid front interaction in an attempt to anticipate non-uniformities in the solid. The study has shown that the method of metal delivery into the mold, the upper region where solidification initiates, is critical in determining the flow of

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

    NASA Astrophysics Data System (ADS)

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

    2012-08-01

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

  7. Modelling of macrosegregation in direct chill casting considering columnar-to-equiaxed transition using 3-phase Eulerian approach

    NASA Astrophysics Data System (ADS)

    Hao, J.; Lin, Y. J.; Nie, Y.; Wu, M.; Ludwig, A.

    2015-06-01

    A 3-phase Eulerian approach is used to model the macrosegregation during solidification in direct chill (DC) casting of binary bronze (Cu-Sn). The three phases are the melt, the solidifying columnar dendrites and the equiaxed grains. The thermodynamic information of Cu-Sn is included based on published thermodynamic data, which are coupled with the 3-phase solidification model. The occurrence of columnar-to-equiaxed transition (CET), phase interactions, feeding flow, equiaxed sedimentation and their influence on macrosegregation are considered in the model. The model is applied to a laboratory DC casting process of bronze as a benchmark to demonstrate the model potentials. The simulation results of mixed columnar and equiaxed solidification as well as the formation of macrosegregation are presented. The focus of this work is to analyze and discuss the macrosegregation mechanisms by different flow including feeding flow and crystal sedimentation.

  8. A mathematical model of the heat and fluid flows in direct-chill casting of aluminum sheet ingots and billets

    NASA Astrophysics Data System (ADS)

    Mortensen, Dag

    1999-02-01

    A finite-element method model for the time-dependent heat and fluid flows that develop during direct-chill (DC) semicontinuous casting of aluminium ingots is presented. Thermal convection and turbulence are included in the model formulation and, in the mushy zone, the momentum equations are modified with a Darcy-type source term dependent on the liquid fraction. The boundary conditions involve calculations of the air gap along the mold wall as well as the heat transfer to the falling water film with forced convection, nucleate boiling, and film boiling. The mold wall and the starting block are included in the computational domain. In the start-up period of the casting, the ingot domain expands over the starting-block level. The numerical method applies a fractional-step method for the dynamic Navier-Stokes equations and the “streamline upwind Petrov-Galerkin” (SUPG) method for mixed diffusion and convection in the momentum and energy equations. The modeling of the start-up period of the casting is demonstrated and compared to temperature measurements in an AA1050 200×600 mm sheet ingot.

  9. Microstructure and Mechanical Properties of Al-8 pct Si Alloy Prepared by Direct Chill Casting Under Electromagnetic and Ultrasonic Fields

    NASA Astrophysics Data System (ADS)

    Zhang, Yubo; Jie, Jinchuan; Wu, Li; Fu, Ying; Li, Mu; Lu, Yiping; Li, Tingju

    2014-04-01

    The intermediate frequency electromagnetic field and power ultrasonic field were applied during the direct chill (DC) casting process of Al-8 pct Si alloy. The effects of different physical fields on the solidification microstructure and mechanical properties were studied. The results show that compared to the conventional casting without any treatments, refined microstructures and improved mechanical properties can be obtained when the electromagnetic or ultrasonic field is applied individually. For the case of compound fields, the electromagnetic field can increase the ultrasonic treated region, while the ultrasonic field can enhance the refinement effect of electromagnetic field. Owing to the advantages of both electromagnetic and ultrasonic fields, the microstructure obtained under the compound fields is fine and uniform, leading to a remarkable enhancement of mechanical properties. The interaction mechanism between intermediate frequency electromagnetic field and power ultrasonic field was discussed. The present study may be useful for grain refinement and improvement of mechanical properties of alloys during the DC casting process which is now widely used in industry.

  10. Surface formation in direct chill (DC) casting of 6082 aluminium alloys

    NASA Astrophysics Data System (ADS)

    Bayat, N.; Carlberg, T.

    2016-03-01

    Surface defects in aluminium billet production are a real problem for the subsequent extrusion procedure. Extrusion productivity can be influenced by the surface properties, which is defined as surface appearance, surface segregation zone depth and large Mg2Si and β-particles (Al5FeSi). In this research the surface formation during DC casting of 6082 aluminium billets produced by the air slip technology is studied. The surface microstructures of 6082 aluminium alloys with smooth and wavy surface appearances were investigated, including segregation zone depths and phase formation. The results were discussed based on the exudation of liquid metal through the mushy zone. The specific appearance of the wavy surface of 6082 alloys was correlated to how the oxide skin adheres to the underlying mushy zone and coupled to the dendritic coherency and surface tension of the skin. The occurrence of different phases at the very surface and in the layer just below was explained by variations in solidification directions and subsequent segregation patterns.

  11. Stress-Strain Predictions of Semisolid Al-Mg-Mn Alloys During Direct Chill Casting: Effects of Microstructure and Process Variables

    NASA Astrophysics Data System (ADS)

    Jamaly, Nasim; Phillion, A. B.; Drezet, J.-M.

    2013-10-01

    The occurrence of hot tearing during the industrial direct chill (DC) casting process results in significant quality issues and a reduction in productivity. In order to investigate their occurrence, a new semisolid constitutive law (Phillion et al.) for AA5182 that takes into account cooling rate, grain size, and porosity has been incorporated within a DC casting finite element process model for round billets. A hot tearing index was calculated from the semisolid strain predictions from the model. This hot tearing index, along with semisolid stress-strain predictions from the model, was used to perform a sensitivity analysis on the relative effects of microstructural features ( e.g., grain size, coalescence temperature) as well as process parameters ( e.g., casting speed) on hot tearing. It was found that grain refinement plays an important role in the formation of hot cracks. In addition, the combination of slow casting speeds and a low temperature for mechanical coalescence was found to improve hot tearing resistance.

  12. Experimental Determination of Heat Transfer Across the Metal/Mold Gap in a Direct Chill (DC) Casting Mold—Part I: Effect of Gap Size and Mold Gas Type

    NASA Astrophysics Data System (ADS)

    Prasad, Arvind; Bainbridge, Ian

    2013-01-01

    An experimental apparatus to determine the heat-transfer coefficient in the gap formed between the cast metal and the mold wall of a vertical direct chill (DC) casting mold is described. The apparatus simulates the conditions existing within the confines of the DC casting mold and measures the heat flux within the gap. Measurements were made under steady-state conditions, simulating the steady-state regime of the DC casting process. A range of casting parameters that may affect the heat transfer was tested using this apparatus. In the current article, the operation of the apparatus is described along with the results for the effect of gas type within the mold, and the size of the metal-mold gap formed during casting. The results show that the gas type and the gap size significantly affect the heat transfer within a DC casting mold. The measured heat fluxes for all the conditions tested were expressed as a linear correlation between the heat-transfer coefficient and the metal-mold gap size, and the fluxes can be used to estimate the heat transfer between the metal and the mold at any gap size. These results are compared to values reported in the literature and recommendations are made for the future reporting of the metal/mold heat-transfer coefficient for DC casting. The results for the effect of the other parameters tested are described in Part II of the article.

  13. Effect of cerium addition on casting/chill interfacial heat flux and casting surface profile during solidification of Al-14%Si alloy

    NASA Astrophysics Data System (ADS)

    Vijeesh, V.; Prabhu, K. N.

    2016-03-01

    In the present investigation, Al-14 wt. % Si alloy was solidified against copper, brass and cast iron chills, to study the effect of Ce melt treatment on casting/chill interfacial heat flux transients and casting surface profile. The heat flux across the casting/chill interface was estimated using inverse modelling technique. On addition of 1.5% Ce, the peak heat flux increased by about 38%, 42% and 43% for copper, brass and cast iron chills respectively. The effect of Ce addition on casting surface texture was analyzed using a surface profilometer. The surface profile of the casting and the chill surfaces clearly indicated the formation of an air gap at the periphery of the casting. The arithmetic average value of the profile departure from the mean line (Ra) and arithmetical mean of the absolute departures of the waviness profile from the centre line (Wa) were found to decrease on Ce addition. The interfacial gap width formed for the unmodified and Ce treated casting surfaces at the periphery were found to be about 35µm and 13µm respectively. The enhancement in heat transfer on addition of Ce addition was attributed to the lowering of the surface tension of the liquid melt. The gap width at the interface was used to determine the variation of heat transfer coefficient (HTC) across the chill surface after the formation of stable solid shell. It was found that the HTC decreased along the radial direction for copper and brass chills and increased along radial direction for cast iron chills.

  14. Directional distribution of chilling winds in Estonia.

    PubMed

    Saue, Triin

    2016-08-01

    Wind chill equivalent temperature (WCET) is used to define thermal discomfort in winter months. Directional distributions of winds, which are associated with uncomfortable weather, were composed of three climatologically different Estonian locations: Vilsandi, Kuusiku, and Jõhvi. Cases with wind chill equivalent temperature <-10 °C, which could be classified as "uncomfortable or worse," were investigated. Additional thresholds were used to measure weather risk. The 25th percentile of daily minimum WCET was tested to measure classical prevalent wind directions in Estonia: W, SW, and NW bring warm air in winter from the North Atlantic, while winds from the East-European plain (NE, E, and SE) are associated with cold air. The eastern prevalence was stronger when a lower threshold was used. A directional approach may find several applications, such as building, agricultural, landscape, or settlement planning.

  15. Directional distribution of chilling winds in Estonia

    NASA Astrophysics Data System (ADS)

    Saue, Triin

    2016-08-01

    Wind chill equivalent temperature (WCET) is used to define thermal discomfort in winter months. Directional distributions of winds, which are associated with uncomfortable weather, were composed of three climatologically different Estonian locations: Vilsandi, Kuusiku, and Jõhvi. Cases with wind chill equivalent temperature <-10 °C, which could be classified as "uncomfortable or worse," were investigated. Additional thresholds were used to measure weather risk. The 25th percentile of daily minimum WCET was tested to measure classical prevalent wind directions in Estonia: W, SW, and NW bring warm air in winter from the North Atlantic, while winds from the East-European plain (NE, E, and SE) are associated with cold air. The eastern prevalence was stronger when a lower threshold was used. A directional approach may find several applications, such as building, agricultural, landscape, or settlement planning.

  16. Numerical discretization of species equation source terms in binary mixture models of solidification and their impact on macrosegregation in semicontinuous, direct chill casting systems

    SciTech Connect

    Vreeman, C.J.; Incropera, F.P.

    1999-07-01

    A discretization procedure for species equation source terms in mixture models of solidification that has been widely applied to static castings was shown to provide erroneous results when applied to semicontinuous casting systems due to the inconsistent, simultaneous use of both upwind and central-difference assumptions. Through a simplified example, a corrected discretized form for species equation terms was derived using consistent upwinding procedures. Sample calculations performed for DC casting of an Al-4.5 wt% Cu billet revealed that the false segregation arising from inconsistently discretized species equation terms overwhelms true, physical segregation due to the buoyancy-driven flow of solute-rich liquid and the settling of solute-depleted, free-floating dendrites.

  17. Electromagnetic Casting of Copper Alloys

    NASA Astrophysics Data System (ADS)

    Tyler, D. E.; Lewis, B. G.; Renschen, P. D.

    1985-09-01

    Electromagnetic (EMC) casting technology has been successfully developed for copper base alloys. This casting technique eliminates the mold related defects normally encountered in direct chill (DC) mold casting, and provides castings with greatly improved hot workability.

  18. Application of Internal Fusible Chills in Thick-Walled Castings Made of EN-GJS with an Optimized Microstructure

    NASA Astrophysics Data System (ADS)

    Krupa, Wojciech; Tonn, Babette

    2011-01-01

    The degeneration of graphite in thick-walled components made of ductile iron due to slower solidification affects the mechanical properties and is unacceptable for all safety-relevant components. The inoculation of the melt no longer leads to a fine microstructure. After exceeding the critical solidification time, degenerated shapes of graphite are to be expected. The external cooling with a chill-mould does not eliminate graphite degeneration in the thermal centres. The positive effect of these chills is also limited by the wall thickness. The aim of this study was to increase the heat dissipation of the melt by positioning the internal fusible chills in the thermal centre of the mould cavity. This should lead to accelerated solidification. The plate-shaped chills were placed in the middle of rectangular samples. The solidification processes were first simulated with Magmasoft in order to optimize the size and shape of the fusible chills and to thus guarantee a complete dissolving of the chills. A reduction in the solidification time of approximately 15% was achieved. In the experiments thick-walled samples were cast with and without internal fusible chills and compared. Areas with degenerated graphite, including chunky graphite, were found in the centres of the cast samples without internal cooling. Placing fusible chills in castings increased the number of graphite spheroids in the microstructure and exhibited no graphite degeneration. A homogenous microstructure was developed—no residues of the chills were found. Differences in microstructure and mechanical properties between the edges and centres of the casting could be nullified. The optimized graphite morphology of the casting with internal cooling led to an increase in tensile strength in the thermal centre of about 30 MPa (8%). This process was successfully implemented in an industrial environment. Blocks out of EN-GJS-400 for use in hydraulic engineering with a total weight of eight tonnes were cast in

  19. Influence of direct and delayed chilling of excised female buffalo muscles on their textural quality.

    PubMed

    Raj, K R; Rao, R J; Rao, D N; Mahendrakar, N S

    2000-09-01

    The excised muscles from the left half of 6 carcasses of old female buffaloes (4-5 years of age) were held, soon after slaughter, at the temperature of 2-3°C for 24 h (direct chilling) and those from the right half at ambient temperature (26±2°C) up to 6 h postmortem followed by chilling at 2-3°C for 18 h (delayed chilling) in order to study the improvement in the texture quality of muscles. During the delayed chilling, the muscle pH decreased to 6.0 (from the initial value of 6.5) in 3 h whereas it took 5-6 h in direct chilling. Reduction in Instron firmness values was 10.3-33.6% and that in cohesiveness values was 13.2-22.2% in delayed chilled muscles compared to direct chilled ones when cooked muscles were sheared along or across the muscle fibres. These observations were statistically significant (P⩽ 0.001) indicating a definite improvement in the texture quality of muscles subjected to delayed chilling. However, no definite trend was observed in the values of elasticity, cooking loss and water holding capacity of muscles due to direct or delayed chilling.

  20. Effects of MC-Type Carbide Forming and Graphitizing Elements on Thermal Fatigue Behavior of Indefinite Chilled Cast Iron Rolls

    NASA Astrophysics Data System (ADS)

    Ahiale, Godwin Kwame; Choi, Won-Doo; Suh, Yongchan; Lee, Young-Kook; Oh, Yong-Jun

    2015-11-01

    The thermal fatigue behavior of indefinite chilled cast iron rolls with various V+Nb contents and Si/Cr ratios was evaluated. Increasing the ratio of Si/Cr prolonged the life of the rolls by reducing brittle cementites. Higher V+Nb addition also increased the life through the formation of carbides that refined and toughened the martensite matrix and reduced the thermal expansion mismatch in the microstructure.

  1. Thin sheet casting with electromagnetic pressurization

    DOEpatents

    Walk, Steven R.; Slepian, R. Michael; Nathenson, Richard D.; Williams, Robert S.

    1991-01-01

    An apparatus, method and system for the casting of thin strips or strips of metal upon a moving chill block that includes an electromagnet located so that molten metal poured from a reservoir onto the chill block passes into the magnetic field produced by the electromagnet. The electromagnet produces a force on the molten metal on said chill block in the direction toward said chill block in order to enhance thermal contact between the molten metal and the chill block.

  2. Casting uniform ceramics with direct coagulation

    SciTech Connect

    Graule, T.J.; Baader, F.H.; Gauckler, L.J.

    1995-06-01

    Today complex-shaped ceramic parts are mass fabricated by many different methods, two of which are slip casting and injection molding. The selection of the appropriate technique is governed by the geometric shape, the number of pieces to be manufactured, and the chemistry of the ceramic. Both slip casting and injection molding introduce imperfections in the green part, which lead to inhomogeneous microstructures in the sintered parts. A new fabrication method, direct coagulation casting (DCC), may be suitable for the mass production of complex ceramic parts with high strength and reliability. In DCC, an aqueous suspension is coagulated by a change in pH or an increase in ionic strength after casting, producing a rigid green body. The use of DCC can avoid most of the limitations of conventional shaping techniques, and it can be applied to a large variety of ceramic powders, sols, and polymers, alone or in combination.

  3. Strip casting apparatus and method

    DOEpatents

    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.

  4. Strip casting apparatus and method

    DOEpatents

    Williams, Robert S.; Baker, Donald F.

    1988-01-01

    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.

  5. Dormancy release and flowering time in Ziziphus jujuba Mill., a "direct flowering" fruit tree, has a facultative requirement for chilling.

    PubMed

    Meir, Michal; Ransbotyn, Vanessa; Raveh, Eran; Barak, Simon; Tel-Zur, Noemi; Zaccai, Michele

    2016-03-15

    In deciduous fruit trees, the effect of chilling on flowering has mostly been investigated in the "indirect flowering" group, characterized by a period of rest between flower bud formation and blooming. In the present study, we explored the effects of chilling and chilling deprivation on the flowering of Ziziphus jujuba, a temperate deciduous fruit tree belonging to the "direct flowering" group, in which flower bud differentiation, blooming and fruit development occur after dormancy release, during a single growing season. Dormancy release, vegetative growth and flowering time in Z. jujuba cv. Ben-Li were assessed following several treatments of chilling. Chilling treatments quantitatively decreased the timing of vegetative bud dormancy release, thereby accelerating flowering, but had no effect on the time from dormancy release to flowering. Trees grown at a constant temperature of 25°C, without chilling, broke dormancy and flowered, indicating the facultative character of chilling in this species. We measured the expression of Z. jujuba LFY and AP1 homologues (ZjLFY and ZjAP1). Chilling decreased ZjLFY expression in dormant vegetative buds but had no effect on ZjAP1expression, which reached peak expression before dormancy release and at anthesis. In conclusion, chilling is not obligatory for dormancy release of Z. jujuba cv. Ben-Li vegetative buds. However, the exposure to chilling during dormancy does accelerate vegetative bud dormancy release and flowering. PMID:26949231

  6. Casting And Solidification Technology (CAST): Directional solidification phenomena in a metal model at reduced gravity

    NASA Technical Reports Server (NTRS)

    Mccay, M. H.

    1988-01-01

    The Casting and Solidification Technology (CAST) experiment will study the phenomena that occur during directional solidification of an alloy, e.g., constitutional supercooling, freckling, and dendrite coarsening. The reduced gravity environment of space will permit the individual phenomena to be examined with minimum complication from buoyancy driven flows.

  7. Influence of heat treatment on the microstructure and wear behavior of end-chill cast Zn-27Al alloys with different copper content

    NASA Astrophysics Data System (ADS)

    Jeshvaghani, R. Arabi; Ghahvechian, H.; Pirnajmeddin, H.; Shahverdi, H. R.

    2016-04-01

    The aim of this paper was to study the effect of heat treatment on the microstructure and wear behavior of Zn-27Al alloys with different copper content. In order to study the relationship between microstructure features and wear behavior, the alloys prepared by an end-chill cast apparatus and then heat treated. Heat treatment procedure involved solutionizing at temperature of 350 °C for 72 h followed by cooling within the furnace to room temperature. Microstructural characteristics of as-cast and heat-treated alloys at different distances from the chill were investigated by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction. Wear tests were performed using a pin-on-disk test machine. To determine the wear mechanisms, the worn surfaces of the samples were also examined by SEM and EDS. Results showed that heat treatment led to the complete dissolution of as-cast dendritic microstructure and formation of a fine lamellar structure with well-distributed microconstituents. Moreover, addition of copper up to 1 wt% had no significant change in the microstructure, while addition of 2 and 4 wt% copper resulted in formation of ɛ (CuZn4) particle in the interdendritic regions. The influence of copper content on the wear behavior of the alloys was explained in terms of microstructural characteristics. Delamination was proposed as the dominant wear mechanism.

  8. The effects of novel surface treatments on the wear and fatigue properties of steel and chilled cast iron

    NASA Astrophysics Data System (ADS)

    Carroll, Jason William

    Contact fatigue driven wear is a principal design concern for gear and camshaft engineering of power systems. To better understand how to engineer contact fatigue resistant surfaces, the effects of electroless nickel and hydrogenated diamond-like-carbon (DLC) coatings on the fatigue life at 108 cycles of SAE 52100 steel were studied using ultrasonic fatigue methods. The addition of DLC and electroless nickel coatings to SAE 52100 bearing steel had no effect on the fatigue life. Different inclusion types were found to affect the stress intensity value beyond just the inclusion size, as theorized by Murakami. The difference in stress intensity values necessary to propagate a crack for Ti (C,N) and alumina inclusions was due to the higher driving force for crack extension at the Ti (C,N) inclusions and was attributed to differences in the shape of the inclusion: rhombohedral for the Ti (C,N) versus spherical for the oxides. A correction factor was added to the Murakami equation to account for inclusion type. The wear properties of DLC coated SAE 52100 and chilled cast iron were studied using pin-on-disk tribometry and very high cycle ultrasonic tribometry. A wear model that includes sliding thermal effects as well as thermodynamics consistent with the wear mechanism for DLCs was developed based on empirical results from ultrasonic wear testing to 108 cycles. The model fit both ultrasonic and classic tribometer data for wear of DLCs. Finally, the wear properties of laser hardened steels - SAE 8620, 4140, and 52100 - were studied at high contact pressures and low numbers of cycles. A design of experiments was conducted to understand how the laser processing parameters of power, speed, and beam size, as well as carbon content of the steel, affected surface hardness. A hardness maximum was found at approximately 0.7 wt% carbon most likely resulting from increased amounts of retained austenite. The ratcheting contact fatigue model of Kapoor was found to be useful in

  9. A metallographic study of porosity and fracture behavior in relation to the tensile properties in 319.2 end chill castings

    SciTech Connect

    Samuel, A.M.; Samuel, F.H.

    1995-09-01

    A metallographic study of the porosity and fracture behavior in unidirectionally solidified end chill castings of 319.2 aluminum alloy (Al-6.2 pct Si-3.8 pct Cu-0.5 pct Fe-0.14 pct Mn-0.06 pct Mg-0.073 pct Ti) was carried out using optical microscopy and scanning electron microscopy (SEM) to determine their relationship with the tensile properties. The parameters varied in the production of these castings were the hydrogen ({approximately}0.1 and {approximately}0.37 mL/100 g Al), modifier (0 and 300 ppm Sr), and grain refiner (0 and 0.03 wt pct Ti) concentrations, as well as the solidification time, which increased with decreasing distance from the end chill bottom of the casting, giving dendrite arm spacings (DASs) ranging from {approximately}15 to {approximately}95 {micro}m. Image analysis and energy dispersive X-ray (EDX) analysis were employed for quantification of porosity/microstructural constituents and fracture surface analysis (phase identification), respectively. The results showed that the local solidification time (viz. DAS) significantly influences the ductility at low hydrogen levels; at higher levels, however, hydrogen has a more pronounced effect (porosity related) on the drop in ductility. Porosity is mainly observed in the form of elongated pores along the grain boundaries, with Sr increasing the porosity volume percent and grain refining increasing the probability for pore branching. The beneficial effect of Sr modification, however, improves the alloy ductility. Fracture of the Si, {beta}-Al{sub 5}FeSi, {alpha}-Al{sub 15}(Fe,Mn){sub 3}Si{sub 2}, and Al{sub 2}Cu phases takes place within the phase particles rather than at the particle/Al matrix interface. Sensitivity of tensile properties to DAS allows for the use of the latter as an indicator of the expected properties of the alloy.

  10. Direct metal laser sintering: a digitised metal casting technology.

    PubMed

    Venkatesh, K Vijay; Nandini, V Vidyashree

    2013-12-01

    Dental technology is undergoing advancements at a fast pace and technology is being imported from various other fields. One such imported technology is direct metal laser sintering technology for casting metal crowns. This article will discuss the process of laser sintering for making metal crowns and fixed partial dentures with a understanding of their pros and cons. PMID:24431766

  11. Producing Foils From Direct Cast Titanium Alloy Strip

    NASA Technical Reports Server (NTRS)

    Stuart, T. A.; Gaspar, T. A.; Sukonnik, I. M.; Semiatan, S. L.; Batawi, E.; Peters, J. A.; Fraser, H. L.

    1996-01-01

    This research was undertaken to demonstrate the feasibility of producing high-quality, thin-gage, titanium foil from direct cast titanium strip. Melt Overflow Rapid Solidification Technology (MORST) was used to cast several different titanium alloys into 500 microns thick strip, 10 cm wide and up to 3 m long. The strip was then either ground, hot pack rolled or cold rolled, as appropriate, into foil. Gamma titanium aluminide (TiAl) was cast and ground to approximately 100 microns thick foil and alpha-2 titanium aluminide (Ti3AI) was cast and hot pack rolled to approximately 70 microns thick foil. CP Ti, Ti6Al2Sn4Zr2Mo, and Ti22AI23Nb (Orthorhombic), were successfully cast and cold-rolled into good quality foil (less than 125 microns thick). The foils were generally fully dense with smooth surfaces, had fine, uniform microstructures, and demonstrated mechanical properties equivalent to conventionally produced titanium. By eliminating many manufacturing steps, this technology has the potential to produce thin gage, titanium foil with good engineering properties at significantly reduced cost relative to conventional ingot metallurgy processing.

  12. The Friction and Wear Characteristics of SI3N4 Ceramic against SI3N4 Ceramic ZRO2 Ceramic and Chilled Cast Iron and AL2O3 Ceramic Under Dry Friction

    NASA Astrophysics Data System (ADS)

    Tian, Xiao; Niu, Jiangang; Wang, Cuibiao

    The friction and wear of silicon nitride (Si3N4) against silicon nitride (Si3N4) and zirconia (Y-TZP) and chilled cast iron and Alumina sliding under dry friction at room temperature conditions were investigated with pin-on-disk tribometer at sliding speed of 0.56ms-1 and normal load of 50N, 80N, respectively. Based on the variety regulation of the wear maps, the wear mechanisms of the two couples were analyzed. Get the result of friction coefficient and maps of wear Rate of the Pin and the Disk. The results of comparing this couple is Si3N4/ chilled cast iron < Si3N4/ ZrO2< Si3N4/ Si3N4< Si3N4/ Al2O3.

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

    NASA Astrophysics Data System (ADS)

    Chhabra, M.; Singh, R.

    2015-04-01

    Aim of this investigation is to develop a mathematical model for predicting surface roughness of castings produced using ZCast process by employing Buckingham's π-theorem. A relationship has been proposed between surface roughness of castings and shell wall thickness of the shell moulds fabricated using 3D printer. Based on model, experiments were performed to obtain the surface roughness of aluminium, brass and copper castings produced using ZCast process based on 3D printing technique. Based on experimental data, three best fitted third-degree polynomial equations have been established for predicting the surface roughness of castings. The predicted surface roughness values were then calculated using established best fitted equations. An error analysis was performed to compare the experimental and predicted data. The average prediction errors obtained for aluminium, brass and copper castings are 10.6, 2.43 and 3.12 % respectively. The obtained average surface roughness (experimental and predicted) values of castings produced are acceptable with the sand cast surface roughness values range (6.25-25 µm).

  14. Pre-sowing Seed Treatments in Direct-seeded Early Rice: Consequences for Emergence, Seedling Growth and Associated Metabolic Events under Chilling Stress

    PubMed Central

    Wang, Weiqin; Chen, Qian; Hussain, Saddam; Mei, Junhao; Dong, Huanglin; Peng, Shaobing; Huang, Jianliang; Cui, Kehui; Nie, Lixiao

    2016-01-01

    Double direct-seeding for double rice cropping is a simplified, labor saving, and efficient cropping system to improve multiple-crop index and total rice production in central China. However, poor crop establishment of direct-seeded early rice due to chilling stress is the main obstacle to wide spread of this system. A series of experiments were conducted to unravel the effects of pre-sowing seed treatments on emergence, seedling growth and associated metabolic events of direct-seeded early rice under chilling stress. Two seed priming treatments and two seed coating treatments were used in all the experiments. A non-treated control treatment was also maintained for comparison. In both the field and growth chamber studies, seed priming with selenium or salicylic acid significantly enhanced the emergence and seedling growth of rice compared with non-treated control. Nevertheless, such positive effects were not apparent for seed coating treatments. Better emergence and vigorous seedling growth of rice after seed priming was associated with enhanced α-amylase activity, higher soluble sugars contents, and greater respiration rate in primed rice seedlings under chilling stress. Taking together, these findings may provide new avenues for understanding and advancing priming-induced chilling tolerance in direct-seeded early rice in double rice cropping system. PMID:26782108

  15. Pre-sowing Seed Treatments in Direct-seeded Early Rice: Consequences for Emergence, Seedling Growth and Associated Metabolic Events under Chilling Stress.

    PubMed

    Wang, Weiqin; Chen, Qian; Hussain, Saddam; Mei, Junhao; Dong, Huanglin; Peng, Shaobing; Huang, Jianliang; Cui, Kehui; Nie, Lixiao

    2016-01-01

    Double direct-seeding for double rice cropping is a simplified, labor saving, and efficient cropping system to improve multiple-crop index and total rice production in central China. However, poor crop establishment of direct-seeded early rice due to chilling stress is the main obstacle to wide spread of this system. A series of experiments were conducted to unravel the effects of pre-sowing seed treatments on emergence, seedling growth and associated metabolic events of direct-seeded early rice under chilling stress. Two seed priming treatments and two seed coating treatments were used in all the experiments. A non-treated control treatment was also maintained for comparison. In both the field and growth chamber studies, seed priming with selenium or salicylic acid significantly enhanced the emergence and seedling growth of rice compared with non-treated control. Nevertheless, such positive effects were not apparent for seed coating treatments. Better emergence and vigorous seedling growth of rice after seed priming was associated with enhanced α-amylase activity, higher soluble sugars contents, and greater respiration rate in primed rice seedlings under chilling stress. Taking together, these findings may provide new avenues for understanding and advancing priming-induced chilling tolerance in direct-seeded early rice in double rice cropping system.

  16. A Direct Numerical Simulation of Axisymmetric Cryogenic Chill Down in a Pipe in Microgravity

    NASA Astrophysics Data System (ADS)

    Agarwal, Alpana; Chung, J. N.

    2015-05-01

    Cryogenic two-phase flow with phase change heat transfer, consisting of a saturated liquid slug translating in its own superheated vapor in a circular pipe, was numerically simulated. The cryogenic chill down process was simplified by assuming ideal inverted annular flow regime. The method used is based on a sharp interface concept and developed on an Eulerian Cartesian fixed-grid with a cut-cell scheme and marker points to track the moving interface. The unsteady, axisymmetric Navier-Stokes equations in both liquid and vapor phases are solved separately and used to compute the velocity, pressure, and temperature fields and the deformation of the liquid core very accurately. Three most common cryogenic fluids, viz. nitrogen, oxygen, and argon were included in the study. The influence of non-dimensional parameters like Reynolds number Weber number , and Jakob number on flow characteristics was studied by systematically varying only one at a time. was found to affect the mass flow rates, but did not have a significant influence on the wall cooling or the Nusselt number. affected the interface shape at the leading edge of the liquid slug, also influencing the heat transfer and velocity field there. affects all three quantities of interest, i.e., mass flow rate, wall cooling, and the Nusselt number.

  17. Morphological Study of Directionally Freeze-Cast Nickel Foams

    NASA Astrophysics Data System (ADS)

    Jo, Hyungyung; Kim, Min Jeong; Choi, Hyelim; Sung, Yung-Eun; Choe, Heeman; Dunand, David C.

    2016-03-01

    Nickel foams, consisting of 51 to 62 pct aligned, elongated pores surrounded by a network of Ni walls, were fabricated by reduction and sintering of directionally cast suspensions of nanometric NiO powders in water. Use of dispersant in the slurry considerably affected the foam morphology and microstructure at both the micro- and macro-scale, most likely by modifying ice solidification into dendrites (creating the aligned, elongated macro-pores) and NiO powder accumulation in the inter-dendritic space (creating the Ni walls with micro-pores). The mean width of the Ni walls, in foams solidified with and without dispersant, was 21 ± 5 and 75 ± 13 µm, respectively. Additionally, the foams with the dispersant showed less dense walls and rougher surfaces than those without the dispersant. Moreover, the fraction of closed pores present in the foam walls with the dispersant was higher than that of the samples without dispersant. We finally verified the potential energy application of the Ni foam produced in this study by carrying out a preliminary single-cell performance test with the Ni foam sample as the gas diffusion layer on the anode side of a polymer electrolyte membrane fuel cell.

  18. High strength alumina produced by direct coagulation casting

    SciTech Connect

    Baader, F.H.; Will, J.; Tieche, D.

    1995-09-01

    Direct Coagulation Casting is a new colloidal forming technique. Double layer stabilized, concentrated alumina suspensions are solidified by shifting the suspensions pH from 4 towards the isoelectric point at 9 using the in situ enzyme-catalyzed decomposition of urea. This reaction minimizes the repulsive forces between the suspended particles. The remaining, attractive Van der Waals forces form a stiff particle network. Suspensions with low viscosities (0.3 Pa*s, 59 vol%) were prepared at pH 4. Deagglomeration of the suspensions by ball milling reduced the agglomerate size below 5 pm. The coagulation kinetics could be influenced either by the urease concentration or by the suspension temperature. Process variables were established, providing long idle times, which allowed additional filtration and degassing steps. Coagulation was followed by drying and sintering, whereby densities of more than 3.97 g/cm{sup 3}, a 4-point bending strength of 685 MPa (HIPed) and a high reliablility (m = 40) for high purity alumina were achieved. DCC has the potential to improve the reliability of alumina components of complex shape, as well as to avoid expensive molding.

  19. Direct transfer of the position of digitized casts to a virtual articulator.

    PubMed

    Solaberrieta, Eneko; Mínguez, Rikardo; Barrenetxea, Lander; Etxaniz, Olatz

    2013-06-01

    This article describes a digital technique to transfer the location of digitized casts obtained directly from the patient to a virtual articulator (digital/virtual facebow transfer). The primary advantage of this technique is that it allows the dentist and the dental laboratory technician to work in a fully digital environment without having to mount stone casts on a physical articulator. This results in a significant time reduction and a higher degree of accuracy in the cast location.

  20. Multiscale Modeling and Simulation of Directional Solidification Process of Turbine Blade Casting with MCA Method

    NASA Astrophysics Data System (ADS)

    Xu, Qingyan; Zhang, Hang; Qi, Xiang; Liu, Baicheng

    2014-04-01

    Nickel-based superalloy turbine blade castings are widely used as a key part in aero engines. However, due to the complex manufacturing processes, the complicated internal structure, and the interaction between different parts of the turbine blade, casting defects, such as stray grains, often happen during the directional solidification of turbine blade castings, which causes low production yield and high production cost. To improve the quality of the directionally solidified turbine blade castings, modeling and simulation technique has been employed to study the microstructure evolution as well as to optimize the casting process. In this article, a modified cellular automaton (MCA) method was used to simulate the directional solidification of turbine blade casting. The MCA method was coupled with macro heat transfer and micro grain growth kinetics to simulate the microstructure evolution during the directional solidification. In addition, a ray tracing method was proposed to calculate the heat transfer, especially the heat radiation of multiple blade castings in a Bridgman furnace. A competitive mechanism was incorporated into the grain growth model to describe the grain selection behavior phenomena of multiple columnar grains in the grain selector. With the proposed models, the microstructure evolution and related defects could be simulated, while the processing parameters optimized and the blade casting quality guaranteed as well. Several experiments were carried out to validate the proposed models, and good agreement between the simulated and experimental results was achieved.

  1. Artificial selection on chill-coma recovery time in Drosophila melanogaster: Direct and correlated responses to selection.

    PubMed

    Gerken, Alison R; Mackay, Trudy F C; Morgan, Theodore J

    2016-07-01

    Artificial selection can be used to create populations with extreme phenotypic responses to environmental stressors. When artificial selection is applied to a single component of a stress response, this selection may result in correlated responses in other stress responses, a phenomenon called cross-tolerance, which is ultimately controlled by the genetic correlations among traits. We selected for extreme responses to cold tolerance by selecting for chill-coma recovery time from a single temperate population of Drosophila melanogaster. Chill-coma recovery time is a common metric of low, but non-lethal, cold temperature tolerance. Replicated divergent artificial selection was applied to a genetically variable base population for 31 generations, resulting in two cold resistant, two cold susceptible, and two unselected control lines. To quantify the relationship between selection on chill-coma recovery and other metrics of thermal performance, we also measured survivorship after acute cold exposure, survivorship after chronic cold exposure, survivorship after cold exposure following a pre-treatment period (rapid cold hardening), starvation tolerance, and heat tolerance. We find that chill-coma recovery time is heritable within this population and that there is an asymmetric response to increased and decreased chill-coma recovery time. Surprisingly, we found no cross-tolerances between selection on chill-coma recovery time and the other environmental stress response traits. These results suggest that although artificial selection has dramatically altered chill-coma recovery time, the correlated response to selection on other stress response phenotypes has been negligible. The lack of a correlated response suggests that chill-coma recovery time in these selection lines is likely genetically independent from measures of cold survivorship tested here. PMID:27264892

  2. Artificial selection on chill-coma recovery time in Drosophila melanogaster: Direct and correlated responses to selection.

    PubMed

    Gerken, Alison R; Mackay, Trudy F C; Morgan, Theodore J

    2016-07-01

    Artificial selection can be used to create populations with extreme phenotypic responses to environmental stressors. When artificial selection is applied to a single component of a stress response, this selection may result in correlated responses in other stress responses, a phenomenon called cross-tolerance, which is ultimately controlled by the genetic correlations among traits. We selected for extreme responses to cold tolerance by selecting for chill-coma recovery time from a single temperate population of Drosophila melanogaster. Chill-coma recovery time is a common metric of low, but non-lethal, cold temperature tolerance. Replicated divergent artificial selection was applied to a genetically variable base population for 31 generations, resulting in two cold resistant, two cold susceptible, and two unselected control lines. To quantify the relationship between selection on chill-coma recovery and other metrics of thermal performance, we also measured survivorship after acute cold exposure, survivorship after chronic cold exposure, survivorship after cold exposure following a pre-treatment period (rapid cold hardening), starvation tolerance, and heat tolerance. We find that chill-coma recovery time is heritable within this population and that there is an asymmetric response to increased and decreased chill-coma recovery time. Surprisingly, we found no cross-tolerances between selection on chill-coma recovery time and the other environmental stress response traits. These results suggest that although artificial selection has dramatically altered chill-coma recovery time, the correlated response to selection on other stress response phenotypes has been negligible. The lack of a correlated response suggests that chill-coma recovery time in these selection lines is likely genetically independent from measures of cold survivorship tested here.

  3. Interfacial shear strength of cast and directionally solidified NiAl-sapphire fiber composites

    NASA Astrophysics Data System (ADS)

    Tewari, S. N.; Asthana, R.; Noebe, R. D.

    1993-09-01

    The feasibility of fabricating intermetallic NiAl-sapphire fiber composites by casting and zone directional solidification has been examined. The fiber-matrix interfacial shear strengths measured using a fiber push-out technique in both cast and directionally solidified composites are greater than the strengths reported for composites fabricated by powder cloth process using organic binders. Microscopic examination of fibers extracted from cast, directionally solidified (DS), and thermally cycled composites, and the high values of interfacial shear strengths suggest that the fiber-matrix interface does not degrade due to casting and directional solidification. Sapphire fibers do not pin grain boundaries during directional solidification, suggesting that this technique can be used to fabricate sapphire fiber reinforced NiAl composites with single crystal matrices.

  4. Interfacial Shear Strength of Cast and Directionally Solidified Nial-Sapphire Fiber Composites

    NASA Technical Reports Server (NTRS)

    Tewari, S. N.; Asthana, R.; Noebe, R. D.

    1993-01-01

    The feasibility of fabricating intermetallic NiAl-sapphire fiber composites by casting and zone directional solidification has been examined. The fiber-matrix interfacial shear strengths measured using a fiber push-out technique in both cast and directionally solidified composites are greater than the strengths reported for composites fabricated by powder cloth process using organic binders. Microscopic examination of fibers extracted from cast, directionally solidified (DS), and thermally cycled composites, and the high values of interfacial shear strengths suggest that the fiber-matrix interface does not degrade due to casting and directional solidification. Sapphire fibers do not pin grain boundaries during directional solidification, suggesting that this technique can be used to fabricate sapphire fiber reinforced NiAl composites with single crystal matrices.

  5. Soft capacitive tactile sensing arrays fabricated via direct filament casting

    NASA Astrophysics Data System (ADS)

    Li, Bin; Gao, Yang; Fontecchio, Adam; Visell, Yon

    2016-07-01

    Advances in soft electronics are enabling the development of mechanical sensors that can conform to curved surfaces or soft objects, allowing them to interface seamlessly with the human body. In this paper, we report on intrinsically deformable tactile sensing arrays that achieve a unique combination of high spatial resolution, sensitivity, and mechanical stretchability. The devices are fabricated via a casting process that yields arrays of microfluidic channels in low modulus polymer membranes with thickness as small as one millimeter. Using liquid metal alloy as a conductor, we apply matrix-addressed capacitive sensing in order to resolve spatially distributed strain with millimeter precision over areas of several square centimeters. Due to the use of low-modulus polymers, the devices readily achieve stretchability greater than 500%, making them well suited for novel applications in wearable tactile sensing for biomedical applications.

  6. Modeling of Heat Transfer and Interdendritic Strain for Exuded Surface Segregation Layer in the Direct Chill Casting of Aluminum Alloys

    NASA Astrophysics Data System (ADS)

    El-Bealy, Mostafa Omar

    2016-02-01

    This investigation on the formation of exuded surface segregation layer " ESSL" is intended to provide experimental and simulated comparison to verify the model developed previously by El-Bealy. Preliminary verification and calibration of the previous 2D mathematical model are demonstrated by quantitative errors between the previous measurements and predictions of temperature and macrosegregation. Also, the results from these comparisons reveal that the errors are in the reasonable and within allowable limits. These comparisons lead to the fact that the exuded surface segregation layer mostly forms on the middle slice of broad sheet ingot face and in the early stages of mold zone. The model predictions point out also that the different interdendritic strain hypotheses associated with fluctuations of mold cooling conditions. This affects the interdendritic liquid flow between the equiaxed crystals which influences the severity of ESSL formation and its macrosegregation level. The mechanism of ESSL with heat flow and interdendritic strain generation has been analyzed and discussed. The quantitative comparisons between the pervious experimental results and numerical simulation in this investigation reveal also several solutions to prevent this defect for future work.

  7. Refinement of Promising Coating Compositions for Directionally Cast Eutectics

    NASA Technical Reports Server (NTRS)

    Strangman, T. E.; Felten, E. J.; Benden, R. S.

    1976-01-01

    The successful application of high creep strength, directionally solidified gamma/gamma prime-delta (Ni-19.7Cb-6Cr-2.5Al) eutectic superalloy turbine blades requires the development of suitable coatings for airfoil, root and internal blade surfaces. In order to improve coatings for the gamma/gamma prime-delta alloy, the current investigation had the goals of (1) refining promising coating compositions for directionally solidified eutectics, (2) evaluating the effects of coating/ substrate interactions on the mechanical properties of the alloy, and (3) evaluating diffusion aluminide coatings for internal surfaces. Burner rig cyclic oxidation, furnace cyclic hot corrosion, ductility, and thermal fatigue tests indicated that NiCrAlY+Pt(63 to 127 micron Ni-18Cr-12Al-0.3Y + 6 micron Pt) and NiCrAlY(63 to 127 micron Ni-18Cr-12Al-0.3Y) coatings are capable of protecting high temperature gas path surfaces of eutectic alloy airfoils. Burner rig (Mach 0.37) testing indicated that the useful coating life of the 127 micron thick coatings exceeded 1000 hours at 1366 K (2000 deg F). Isothermal fatigue and furnance hot corrosion tests indicated that 63 micron NiCrAlY, NiCrAlY + Pt and platinum modified diffusion aluminide (Pt + Al) coating systems are capable of protecting the relatively cooler surfaces of the blade root. Finally, a gas phase coating process was evaluated for diffusion aluminizing internal surfaces and cooling holes of air-cooled gamma/gamma prime-delta turbine blades.

  8. DM-2 Chilling

    NASA Video Gallery

    How do you chill down 1.4 million pounds of solid rocket fuel in the hot Utah desert? Lots of air conditioning! Learn how ATK chilled down DM-2, the second Ares first stage development motor in adv...

  9. Interface Formation During Fusion™ Casting of AA3003/AA4045 Aluminum Alloy Ingots

    NASA Astrophysics Data System (ADS)

    Di Ciano, Massimo; Caron, E. J. F. R.; Weckman, D. C.; Wells, M. A.

    2015-12-01

    Fusion™ casting is a unique Direct Chill continuous casting process whereby two different alloys can be cast simultaneously, producing a laminated ingot for rolling into clad sheet metal such as AA3003/AA4045 brazing sheet. Better understanding of the wetting and interface formation process during Fusion™ casting is required to further improve process yields and also explore use of other alloy systems for new applications. In this research, AA3003-core/AA4045-clad ingots were cast using a well-instrumented lab-scale Fusion™ casting system. As-cast Fusion™ interfaces were examined metallurgically and by mechanical testing. Computational fluid dynamic analyses of the FusionTM casts were also performed. It was shown that the liquid AA4045-clad alloy was able to successfully wet and create an oxide-free, metallurgical, and mechanically sound interface with the lightly oxidized AA3003-core shell material. Based on the results of this study, it is proposed that the bond formation process at the alloys interface during casting is a result of discrete penetration of AA4045 liquid at defects in the preexisting AA3003 oxide, dissolution of underlying AA3003 by liquid AA4045, and subsequent bridging between penetration sites. Spot exudation on the AA3003 chill cast surface due to remelting and inverse segregation may also improve the wetting and bonding process.

  10. [Music-induced chills as a strong emotional experience].

    PubMed

    Mori, Kazuma; Iwanaga, Makoto

    2014-12-01

    While enjoying music and other works of art, people sometimes experience "chills," a strong emotional response characterized by a sensation of goose bumps or shivers. Such experiences differ from having goose bumps as a defense response or from shivering in reaction to cold temperatures. The current paper presents the phenomenon of music-induced chills and reviews the chill-related emotional response, autonomic nervous system activity, and brain activity. It also reviews the musico-acoustic features, listening contexts, and individual differences that cause chills. Based on the review, we propose a hypothetical model regarding the evocation of music-induced chills. Furthermore, we investigate the strong emotional response associated with chills by exploring the relationship between music-related chills and non-music-related chills, and discuss future research directions. PMID:25639033

  11. [Music-induced chills as a strong emotional experience].

    PubMed

    Mori, Kazuma; Iwanaga, Makoto

    2014-12-01

    While enjoying music and other works of art, people sometimes experience "chills," a strong emotional response characterized by a sensation of goose bumps or shivers. Such experiences differ from having goose bumps as a defense response or from shivering in reaction to cold temperatures. The current paper presents the phenomenon of music-induced chills and reviews the chill-related emotional response, autonomic nervous system activity, and brain activity. It also reviews the musico-acoustic features, listening contexts, and individual differences that cause chills. Based on the review, we propose a hypothetical model regarding the evocation of music-induced chills. Furthermore, we investigate the strong emotional response associated with chills by exploring the relationship between music-related chills and non-music-related chills, and discuss future research directions.

  12. Effect of casting/mould interfacial heat transfer during solidification of aluminium alloys cast in CO2-sand mould

    NASA Astrophysics Data System (ADS)

    Kulkarni, S. N.; Radhakrishna, D. K.

    2011-06-01

    The ability of heat to flow across the casting and through the interface from the casting to the mold directly affects the evolution of solidification and plays a notable role in determining the freezing conditions within the casting, mainly in foundry systems of high thermal diffusivity such as chill castings. An experimental procedure has been utilized to measure the formation process of an interfacial gap and metal-mould interfacial movement during solidification of hollow cylindrical castings of Al-4.5 % Cu alloy cast in CO2-sand mould. Heat flow between the casting and the mould during solidification of Al-4.5 % Cu alloy in CO2-sand mould was assessed using an inverse modeling technique. The analysis yielded the interfacial heat flux ( q), heat transfer coefficient ( h) and the surface temperatures of the casting and the mould during solidification of the casting. The peak heat flux was incorporated as a dimensionless number and modeled as a function of the thermal diffusivities of the casting and the mould materials. Heat flux transients were normalized with respect to the peak heat flux and modeled as a function of time. The heat flux model proposed was to estimate the heat flux transients during solidification of Al-4.5 % Cu alloy cast in CO2-sand moulds.

  13. Directional solidification of large cross-section nickel-base superalloy castings via liquid-metal cooling

    NASA Astrophysics Data System (ADS)

    Elliott, Andrew J.

    The drive for higher efficiency in very large industrial gas turbines (IGTs) used in power generation applications has led to the need for directional solidification of large cross-section components, such as turbine blades, used in the hot gas path sections of the IGTs. The Bridgman directional solidification technique, which is currently used to produce these components, has been optimized for much smaller aero-engine components. The scale-up of this technique to produce large parts has resulted in numerous problems, and consequently low casting yield, which can all be related to the limited cooling capability of the Bridgman process. In this dissertation, a higher cooling efficiency process, liquid-metal cooling (LMC) using Sn as the cooling medium, has been evaluated for improved capability to cast large cross-section components. A series of castings were made for direct comparison using both the conventional Bridgman and the high thermal gradient LMC processes. Casting conditions were selected to simulate the state of the art for the Bridgman method and to assess the limits of casting with the less familiar LMC method. The experiments were evaluated through thermocouple analyses of casting conditions and post-casting analyses of grain defects, microstructural features, and mechanical behavior. Additionally, a finite element model of the solidification process was developed to further elucidate casting conditions. The casting parameters and elements of the LMC process that had the greatest influence on casting conditions were determined. Results indicated that the LMC process is capable of significantly enhancing cooling efficiency during directional solidification of large cross-section components. The enhanced cooling allowed much faster solidification withdrawal rates and resulted in substantially refined cast microstructure. The LMC process eliminated freckle-type defects in all cases and considerably reduced other casting defects under optimal conditions

  14. An evaluation of direct pressure sensors for monitoring the aluminum die casting process

    SciTech Connect

    Zhang, X.

    1997-12-31

    This study was conducted as part of the US Department of Energy (DOE) sponsored project Die Cavity Instrumentation. One objective of that project was to evaluate thermal, pressure, and gas flow process monitoring sensors in or near the die cavity as a means of securing improved process monitoring and control and better resultant part quality. The objectives of this thesis are to (1) evaluate a direct cavity pressure sensor in a controlled production campaign at the GM Casting Advanced Development Center (CADC) at Bedford, Indiana; and (2) develop correlations between sensor responses and product quality in terms of the casting weight, volume, and density. A direct quartz-based pressure sensor developed and marked by Kistler Instrument Corp. was acquired for evaluating as an in-cavity liquid metal pressure sensor. This pressure sensor is designed for use up to 700 C and 2,000 bars (29,000 psi). It has a pressure overload capacity up to 2,500 bars (36,250 psi).

  15. Real-time video monitoring of ingot casting

    SciTech Connect

    Richter, R.T.; Adomaitis, P.R.; Hildeman, G.J.

    1996-10-01

    During start-up and steady-state casting of ingots, a number of effects related to ingot casting variables can be observed on the surface of the ingot. For example, the amount of curl at the bottom of the ingot, surface laps, liquation, cracks, and folds, as well as extreme events such as bleed-outs when molten metal melts through the shell of the ingot crater, are significant events which could be viewed. Unfortunately, observation of these surface effects is difficult since the as-cast surface is hidden below the casting table and direct visual observations of ingot surfaces are limited due to the proximity of the molds, cooling water sprays, and the ability of the casting operators to safely view ingot surface details at close range. The purpose of this paper is to describe a unique video monitoring capability which is being used as Alcoa`s Advanced Vertical Casting facility, to observe in real-time, surface effects of an ingot during casting. A description of the development of the video monitoring system, including camera, lighting, and video recording capability will be presented. Examples of various surface conditions on direct chill (DC) and electromagnetic cast (EMC) ingots will also be discussed.

  16. The chilling of carcasses.

    PubMed

    Savell, J W; Mueller, S L; Baird, B E

    2005-07-01

    Biochemical processes and structural changes that occur in muscle during the first 24h postmortem play a great role in the ultimate quality and palatability of meat and are influenced by the chilling processes that carcasses are subjected to after slaughter. For beef and lamb, employing chilling parameters that minimize cold shortening is of greatest importance and can be best addressed by ensuring that muscle temperatures are not below 10°C before pH reaches 6.2. For pork, because of the impact of high muscle temperatures and low pH on the development of pale, soft, and exudative (PSE) pork, a more rapid chilling process is needed to reduce PSE with the recommended internal muscle temperature of 10°C at 12h and 2-4°C at 24h. Spray chilling, a system whereby chilled water is applied to carcasses during the early part of postmortem cooling, is used to control carcass shrinkage and to improve chilling rates through evaporative cooling. Delayed chilling can be used to reduce or prevent the negative effects of cold shortening; however, production constraints in high-volume facilities and food safety concerns make this method less useful in commercial settings. Electrical stimulation and alternative carcass suspension programs offer processors the opportunity to negate most or all of the effects of cold shortening while still using traditional chilling systems. Rapid or blast chilling can be an effective method to reduce the incidence of PSE in pork but extreme chilling systems may cause quality problems because of the differential between the cold temperatures on the outside of the carcass compared to the warm muscle temperatures within the carcass (i.e., muscles that are darker in color externally and lighter in color internally).

  17. CENTRIFUGAL CASTING MACHINE

    DOEpatents

    Shuck, A.B.

    1958-04-01

    A device is described that is specifically designed to cast uraniumn fuel rods in a vacuunn, in order to obtain flawless, nonoxidized castings which subsequently require a maximum of machining or wastage of the expensive processed material. A chamber surrounded with heating elements is connected to the molds, and the entire apparatus is housed in an airtight container. A charge of uranium is placed in the chamber, heated, then is allowed to flow into the molds While being rotated. Water circulating through passages in the molds chills the casting to form a fine grained fuel rod in nearly finished form.

  18. Effects of the location of a cast in the furnace on flatness of the solidification front in directional solidification

    NASA Astrophysics Data System (ADS)

    Lian, Yuanyuan; Li, Dichen; Zhang, Kai

    2016-10-01

    Many defects of single crystals are caused by the nonplanar solidification front. The transverse temperature gradient at melt-crystal interface results in nonplanar solidification fronts. The location of a cast in the directional solidification furnace affects heat dissipation and thus influences the transverse temperature gradient. This paper presents a criterion and a searching algorithm to find the optimal location of the cast for flattening the solidification front. A numerical simulation was employed for the verification of our method. Additionally, the effects of the size of the cooling device of the furnace on the optimal location, the transverse temperature gradient and the solidification time were discussed. The transverse temperature gradient is reduced about 50% without increasing much solidification time when setting the cast with a varying thickness mould at the optimal location. In addition, the optimal location is mainly influenced by the radius of the cooling ring.

  19. Metallic Reinforcement of Direct Squeeze Die Casting Aluminum Alloys for Improved Strength and Fracture Resistance

    SciTech Connect

    D. Schwam: J.F. Wallace: Y. Zhu: J.W. Ki

    2004-10-01

    The utilization of aluminum die casting as enclosures where internal equipment is rotating inside of the casting and could fracture requires a strong housing to restrain the fractured parts. A typical example would be a supercharger. In case of a failure, unless adequately contained, fractured parts could injure people operating the equipment. A number of potential reinforcement materials were investigated. The initial work was conducted in sand molds to create experimental conditions that promote prolonged contact of the reinforcing material with molten aluminum. Bonding of Aluminum bronze, Cast iron, and Ni-resist inserts with various electroplated coatings and surface treatments were analyzed. Also toughening of A354 aluminum cast alloy by steel and stainless steel wire mesh with various conditions was analyzed. A practical approach to reinforcement of die cast aluminum components is to use a reinforcing steel preform. Such performs can be fabricated from steel wire mesh or perforated metal sheet by stamping or deep drawing. A hemispherical, dome shaped casting was selected in this investigation. A deep drawing die was used to fabricate the reinforcing performs. The tendency of aluminum cast enclosures to fracture could be significantly reduced by installing a wire mesh of austenitic stainless steel or a punched austenitic stainless steel sheet within the casting. The use of reinforcements made of austenitic stainless steel wire mesh or punched austenitic stainless steel sheet provided marked improvement in reducing the fragmentation of the casting. The best strengthening was obtained with austenitic stainless steel wire and with a punched stainless steel sheet without annealing this material. Somewhat lower results were obtained with the annealed punched stainless steel sheet. When the annealed 1020 steel wire mesh was used, the results were only slightly improved because of the lower mechanical properties of this unalloyed steel. The lowest results were

  20. Growth directions of C8-BTBT thin films during drop-casting

    NASA Astrophysics Data System (ADS)

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

    2016-02-01

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

  1. Microstructure and stress-rupture life of polycrystal, directionally solidified, and single crystal castings of nickel-based IN 939 superalloy

    SciTech Connect

    Jovanovic, M.T.; Miskovic, Z.; Lukic, B.

    1998-04-01

    A comparative investigation of microstructural and mechanical properties (stress-rupture life) in conventionally cast, directionally solidified, and single crystal IN 939 superalloy has been undertaken. Directional castings possess only a few columnar grains, all oriented in the <100> crystallographic direction, whereas only one grain is present in a single crystal. Single crystals are characterized by the highest values of stress-rupture life, much higher than those of directionally solidified and, especially, polycrystal castings, which is accounted for by the absence of grain boundaries.

  2. A Chilling Experience.

    ERIC Educational Resources Information Center

    Knill, George; Fawcett, George

    1982-01-01

    Wind chill is detailed and noted as an estimate of how cold the wind makes a person feel in cold weather. A worksheet master that provides a table of temperatures and wind speeds is provided along with a set of problems. Answers to the brief question set are provided. (MP)

  3. Chilling requirement of Ribes cultivars

    PubMed Central

    Jones, Hamlyn G.; Gordon, Sandra L.; Brennan, Rex M.

    2015-01-01

    It is usually thought that adequate winter chill is required for the full flowering of many temperate woody species. This paper investigates the sensitivity of blackcurrant bud burst and flowering to natural weather fluctuations in a temperate maritime climate, and compares a range of chill models that have been proposed for assessing the accumulation of winter chill. Bud break for four contrasting cultivars are compared in an exceptionally cold and in a mild winter in Eastern Scotland. The results confirm the importance of chilling at temperatures lower than 0°C and demonstrate that no single chilling function applies equally to all blackcurrant cultivars. There is a pressing need for further model development to take into account the relationship between chilling temperatures and warming temperatures occurring both during and after the chill accumulation period. PMID:25610448

  4. Calculation of heat transfer coefficients at the ingot surface during DC casting

    SciTech Connect

    Kuwana, K.; Viswanathan, S.; Clark, John A, III; Sabau, A.; Hassan, M.; Saito, K.; Das, S.

    2005-02-01

    Surface heat transfer coefficients representing the various regimes of water cooling during the Direct Chill (DC) casting of aluminum 3004 alloy ingots have been calculated using the inverse heat transfer technique. ProCAST, a commercial casting simulation package, which includes heat transfer, fluid flow, solidification, and inverse heat transfer, was used for this effort. Thermocouple data from an experimental casting run, and temperature-dependent thermophysical properties of the alloy were used in the calculation. The use of a structured vs. unstructured mesh was evaluated. The calculated effective heat transfer coefficient, which is a function of temperature and time, covers three water cooling regimes, i.e., convection, nucleate boiling, and film boiling, and the change of water flow rate with time.

  5. Numerical simulation of casting process to assist in defects reduction in complex steel tidal power component

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

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

  6. Continuous Casting for Aluminum Sheet: a Product Perspective

    NASA Astrophysics Data System (ADS)

    Sanders, Robert E.

    2012-02-01

    Continuous casting processes have been used successfully for more than 50 years to reduce the cost of manufacturing a variety of aluminum rolled products. Approximately 25% of North American flat-rolled sheet and foil is sourced from twin-roll cast or slab cast processes. Twin roll-casters provide a cost-effective solution for producing foil and light-gauge sheet from relatively low-alloyed aluminum (1xxx and 8xxx alloys). Slab casters, particularly Hazelett twin-belt machines, are well utilized in the production of 3xxx or 5xxx painted building products which require moderate strength and good corrosion resistance. Both foil and painted sheet are cost-sensitive commodity products with well-known metallurgical and quality requirements. There have been extensive trials and modest successes with continuous cast can stock and automotive sheet. However, they have not been widely adopted commercially due to generally lower levels of surface quality and formability compared with sheet produced from scalped direct chill (DC) cast ingot. The metallurgical requirements for can and auto sheet are considered in more detail with emphasis on the microstructural features which limit their application, e.g., particle distribution, grain size, and texture. Looking forward, slab casting offers the most viable opportunity for producing strong (i.e., higher alloy content), formable structural auto sheet with acceptable surface quality.

  7. Stepwise chilling: tender pork without compromising water-holding capacity.

    PubMed

    Rosenvold, K; Borup, U; Therkildsen, M

    2010-05-01

    The current pork slaughter process is primarily optimized to reduce cooler shrink and the incidence of PSE pork. Elimination of the halothane gene and improved preslaughter handling have decreased the incidence of PSE pork and improved the water-holding capacity of the muscle; however, the chilling process has not been optimized to accommodate these changes. The hypothesis that stepwise chilling could improve tenderness without compromising water-holding capacity was tested in this study. The stepwise chilling treatments were composed of a rapid chilling to 10 or 15 degrees C (in a chilling tunnel) and a 6-h holding period at 10 or 15 degrees C, followed by rapid chilling to 4 degrees C. Both treatments were compared directly with a chilling treatment that simulated conventional tunnel chilling; one carcass half from each pig was allocated to a stepwise chilling treatment, whereas the other carcass half was allocated to the control treatment. A total of 42 pigs were slaughtered on 6 slaughter days. Biopsies were collected for analysis of glycogen degradation and glycogen debranching enzyme activity from slaughter until 72 h postmortem, and samples for color, sarcomere length, drip loss, Warner-Bratzler shear force, and sensory analysis were removed from the carcass 24 h postmortem. Substantial temperature differences were obtained during the holding period between the stepwise and conventionally chilled carcass halves. These had almost, but not completely, disappeared by 22 h postmortem, and although the differences were small, pH was significantly (P < 0.01) less in the stepwise-chilled carcasses compared with the control carcasses. The stepwise chilling treatments led to significantly improved (P < 0.01) tenderness in LM without compromising quality indicators or attributes such as pH, drip loss, or ham processing yield, although color of the stepwise-chilled pork was affected. Neither the tenderness of processed semimembranosus muscle nor the shear force of

  8. Preliminary science report on the directional solidification of hypereutectic cast iron during KC-135 low-G maneuvers

    NASA Technical Reports Server (NTRS)

    Curreri, P. A.; Stefanescu, D. M.; Hendrix, J. C.

    1983-01-01

    An ADSS-P directional solidification furnace was reconfigured for operation on the KC-135 low-g aircraft. The system offers many advantages over quench ingot methods for study of the effects of sedimentation and convection on alloy formation. The directional sodification furnace system was first flown during the September 1982 series of flights. The microstructure of the hypereutectic cast iron sample solidified on one of these flights suggests a low-g effect on graphite morphology. Further experiments are needed to ascertain that this effect is due to low-gravity and to deduce which of the possible mechanisms is responsible for it.

  9. Fabrication of Porous Copper with Directional Pores by Continuous Casting Technique Through Thermal Decomposition of Hydride

    NASA Astrophysics Data System (ADS)

    Ide, Takuya; Tsunemi, Akihiro; Nakajima, Hideo

    2014-08-01

    Lotus-type porous copper with aligned long cylindrical pores was fabricated by continuous casting technique through thermal decomposition method (TDM) in an argon atmosphere of 0.1 MPa. A pellet of titanium hydride was supplied into molten copper with adjusting the time interval to maintain the constant concentration of hydrogen to be dissolved in the melt, when the transfer velocity of the unidirectional solidification is changed. Long lotus-type porous copper slabs were fabricated with constant solidification velocity. The effect of the transfer velocity on the porosity and pore size was investigated. The average pore diameter was independent of the transfer velocity, but the porosity is slightly dependent on the velocity. It is apparent that the continuous casting technique can be applicable for production of lotus metals through TDM.

  10. Fundamental insights on impact of non-condensible gas evolution from coating pyrolysis and intentional injection on molten-aluminum water explosion onset during direct-chill casting

    SciTech Connect

    Taleyarkhan, R.P.; Kim, S.H.; Gulec, K.

    1998-05-01

    Explosive interactions between molten aluminum and water are being studied with a focus on fundamentals to determine what causes robust-enough triggers for explosion onset, to determine the extent of protection provided from various coatings and to develop a fundamentally-based simple, cost-effective novel methodology for prevention. The workscope includes experimentation and mathematical modeling of the interactions between molten metals and water at various different coated and uncoated surfaces. Phenomenological issues related to surface wettability, gas generation from coatings, charring of coatings, inertial constraint, melt temperature, water temperature, external shocks are being investigated systematically to gage their relative impact on the triggerability of surface-assisted steam explosions. The steam explosion triggering studies (SETS) facility was designed and constructed as a rapid-turnaround, cost-effective, and safe means to address these phenomenological issues. Data from SETS tests have indicated that, non-condensible gas (NCG) generation during paint pyrolysis plays a predominant role in explosion prevention. This paper describes results of studies on impact of deliberate NCG injection on explosion prevention, via molten melt drops free-falling into water, as well as from tests using the SETS facility for studying entrapment induced explosive boiling. SETS is also being used to obtain information on time-varying and integral amounts of NCGs generated from various paints. Relevant data are presented. Results of investigations, taken together provide compelling evidence on the positive role NCGs play on explosion prevention.

  11. Prediction of Hot Tear Formation in Vertical DC Casting of Aluminum Billets Using a Granular Approach

    NASA Astrophysics Data System (ADS)

    Sistaninia, M.; Drezet, J.-M.; Phillion, A. B.; Rappaz, M.

    2013-09-01

    A coupled hydromechanical granular model aimed at predicting hot tear formation and stress-strain behavior in metallic alloys during solidification is applied to the semicontinuous direct chill casting of aluminum alloy round billets. This granular model consists of four separate three-dimensional (3D) modules: (I) a solidification module that is used for generating the solid-liquid geometry at a given solid fraction, (II) a fluid flow module that is used to calculate the solidification shrinkage and deformation-induced pressure drop within the intergranular liquid, (III) a semisolid deformation module that is based on a combined finite element/discrete element method and simulates the rheological behavior of the granular structure, and (IV) a failure module that simulates crack initiation and propagation. To investigate hot tearing, the granular model has been applied to a representative volume within the direct chill cast billet that is located at the bottom of the liquid sump, and it reveals that semisolid deformations imposed on the mushy zone open the liquid channels due to localization of the deformation at grains boundaries. At a low casting speed, only individual pores are able to form in the widest channels because liquid feeding remains efficient. However, as the casting speed increases, the flow of liquid required to compensate for solidification shrinkage also increases and as a result the pores propagate and coalesce to form a centerline crack.

  12. A New Direct-Pour In-Mold (DPI) Technology for Producing Ductile and Compacted Graphite Iron Castings.

    SciTech Connect

    Jason Hitchings; Jay R. Hitchings

    2007-07-20

    A new "Direct Pour In-Mold" (DPI) Magnesium treatment technology has been developed that can produce both Nodular and Compacted Graphite iron. The DPI technology converts the standard horizontal runner system into a vertical one, by placing a Magnesium Ferrosilicon treatment alloy and molten metal filter into a specially designed container. The DPI container is easily placed into either vertically or horizontally parted molds, and then a base metal can be poured directly into it. The metal is treated and filtered as it passes through, and then proceeds directly into a runner or casting cavity. Various sizes of containers provide all of the necessary components required to deliver a range of weights of treated and filtered metal at accurate and consistent flow rates. The DPI containers provide energy savings over competing techniques, increased mold yields, very high Magnesium recovery, zero Magnesium fume, and no post inoculation is required. By treating the metal just prior to it entering a casting cavity many other benefits and advantages are also realized.

  13. Micromechanical Characterization and Texture Analysis of Direct Cast Titanium Alloys Strips

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This research was conducted to determine a post-processing technique to optimize mechanical and material properties of a number of Titanium based alloys and aluminides processed via Melt Overflow Solidification Technique (MORST). This technique was developed by NASA for the development of thin sheet titanium and titanium aluminides used in high temperature applications. The materials investigated in this study included conventional titanium alloy strips and foils, Ti-1100, Ti-24Al-11Nb (Alpha-2), and Ti-48Al-2Ta (Gamma). The methodology used included micro-characterization, heat-treatment, mechanical processing and mechanical testing. Characterization techniques included optical, electron microscopy, and x-ray texture analysis. The processing included heat-treatment and mechanical deformation through cold rolling. The initial as-cast materials were evaluated for their microstructure and mechanical properties. Different heat-treatment and rolling steps were chosen to process these materials. The properties were evaluated further and a processing relationship was established in order to obtain an optimum processing condition. The results showed that the as-cast material exhibited a Widmanstatten (fine grain) microstructure that developed into a microstructure with larger grains through processing steps. The texture intensity showed little change for all processing performed in this investigation.

  14. Urinary casts

    MedlinePlus

    ... the urine; Fatty casts; Red blood cell casts; White blood cell casts ... with advanced kidney disease and chronic kidney failure . White blood cell (WBC) casts are more common with acute kidney ...

  15. PREFACE: MCWASP XIV: International Conference on Modelling of Casting, Welding and Advanced Solidification Processes

    NASA Astrophysics Data System (ADS)

    Yasuda, H.

    2015-06-01

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

  16. Welding Using Chilled-Inert-Gas Purging

    NASA Technical Reports Server (NTRS)

    Mcgee, William F.; Rybicki, Daniel J.

    1995-01-01

    Report describes study of fusion welding using chilled inert gas. Marked improvement shown in welding of aluminum using chilled helium gas. Chilling inert gas produces two additional benefits: 1) creation of ultradense inert atmosphere around welds; 2) chilled gas cools metal more quickly down to temperature at which metals not reactive.

  17. Insights on the development, kinetics, and variation of photoinhibition using chlorophyll fluorescence imaging of a chilled, variegated leaf.

    PubMed

    Hogewoning, Sander W; Harbinson, Jeremy

    2007-01-01

    The effect of chilling on photosystem II (PSII) efficiency was studied in the variegated leaves of Calathea makoyana, in order to gain insight into the causes of chilling-induced photoinhibition. Additionally, a relationship was revealed between (chilling) stress and variation in photosynthesis. Chilling treatments (5 degrees C and 10 degrees C) were performed for different durations (1-7 d) under a moderate irradiance (120 micromol m-2 s-1). The individual leaves were divided into a shaded zone and two illuminated, chilled zones. The leaf tip and sometimes the leaf base were not chilled. Measurements of the dark-adapted Fv/Fm were made on the different leaf zones at the end of the chilling treatment, and then for several days thereafter to monitor recovery. Chilling up to 7 d in the dark did not affect PSII efficiency and visual appearance, whereas chilling in the light caused severe photoinhibition, sometimes followed by leaf necrosis. Photoinhibition increased with the duration of the chilling period, whereas, remarkably, chilling temperature had no effect. In the unchilled leaf tip, photoinhibition also occurred, whereas in the unchilled leaf base it did not. Whatever the leaf zone, photoinhibition became permanent if the mean value dropped below 0.4, although chlorosis and necrosis were associated solely with chilled illuminated tissue. Starch accumulated in the unchilled leaf tip, in contrast to the adjacent chilled irradiated zone. This suggests that photoinhibition was due to a secondary effect in the unchilled leaf tip (sink limitation), whereas it was a direct effect of chilling and irradiance in the chilled illuminated zones. The PSII efficiency and its coefficient of variation showed a unique negative linearity across all leaf zones and different tissue types. The slope of this curve was steeper for chilled leaves than it was for healthy, non-stressed leaves, suggesting that the coefficient of variation may be an important tool for assessing stress in

  18. Insights on the development, kinetics, and variation of photoinhibition using chlorophyll fluorescence imaging of a chilled, variegated leaf.

    PubMed

    Hogewoning, Sander W; Harbinson, Jeremy

    2007-01-01

    The effect of chilling on photosystem II (PSII) efficiency was studied in the variegated leaves of Calathea makoyana, in order to gain insight into the causes of chilling-induced photoinhibition. Additionally, a relationship was revealed between (chilling) stress and variation in photosynthesis. Chilling treatments (5 degrees C and 10 degrees C) were performed for different durations (1-7 d) under a moderate irradiance (120 micromol m-2 s-1). The individual leaves were divided into a shaded zone and two illuminated, chilled zones. The leaf tip and sometimes the leaf base were not chilled. Measurements of the dark-adapted Fv/Fm were made on the different leaf zones at the end of the chilling treatment, and then for several days thereafter to monitor recovery. Chilling up to 7 d in the dark did not affect PSII efficiency and visual appearance, whereas chilling in the light caused severe photoinhibition, sometimes followed by leaf necrosis. Photoinhibition increased with the duration of the chilling period, whereas, remarkably, chilling temperature had no effect. In the unchilled leaf tip, photoinhibition also occurred, whereas in the unchilled leaf base it did not. Whatever the leaf zone, photoinhibition became permanent if the mean value dropped below 0.4, although chlorosis and necrosis were associated solely with chilled illuminated tissue. Starch accumulated in the unchilled leaf tip, in contrast to the adjacent chilled irradiated zone. This suggests that photoinhibition was due to a secondary effect in the unchilled leaf tip (sink limitation), whereas it was a direct effect of chilling and irradiance in the chilled illuminated zones. The PSII efficiency and its coefficient of variation showed a unique negative linearity across all leaf zones and different tissue types. The slope of this curve was steeper for chilled leaves than it was for healthy, non-stressed leaves, suggesting that the coefficient of variation may be an important tool for assessing stress in

  19. Strip casting with fluxing agent applied to casting roll

    DOEpatents

    Williams, Robert S.; O'Malley, Ronald J.; Sussman, Richard C.

    1997-01-01

    A strip caster (10) for producing a continuous strip (24) includes a tundish (12) for containing a melt (14), a pair of horizontally disposed water cooled casting rolls (22) and devices (29) for electrostatically coating the outer peripheral chill surfaces (44) of the casting rolls with a powder flux material (56). The casting rolls are juxtaposed relative to one another for forming a pouting basin (18) for receiving the melt through a teeming tube (16) thereby establishing a meniscus (20) between the rolls for forming the strip. The melt is protected from the outside air by a non-oxidizing gas passed through a supply line (28) to a sealing chamber (26). A preferred flux is boron oxide having a melting point of about 550.degree. C. The flux coating enhances wetting of the steel melt to the casting roll and dissolves any metal oxide formed on the roll.

  20. Strip casting with fluxing agent applied to casting roll

    DOEpatents

    Williams, R.S.; O`Malley, R.J.; Sussman, R.C.

    1997-07-29

    A strip caster for producing a continuous strip includes a tundish for containing a melt, a pair of horizontally disposed water cooled casting rolls and devices for electrostatically coating the outer peripheral chill surfaces of the casting rolls with a powder flux material. The casting rolls are juxtaposed relative to one another for forming a pouting basin for receiving the melt through a teeming tube thereby establishing a meniscus between the rolls for forming the strip. The melt is protected from the outside air by a non-oxidizing gas passed through a supply line to a sealing chamber. A preferred flux is boron oxide having a melting point of about 550 C. The flux coating enhances wetting of the steel melt to the casting roll and dissolves any metal oxide formed on the roll. 3 figs.

  1. Process-directed self-assembly of multiblock copolymers: Solvent casting vs spray coating

    NASA Astrophysics Data System (ADS)

    Tang, Q.; Tang, J.; Müller, M.

    2016-07-01

    Using computer simulation of a soft, coarse-grained model and self-consistent field theory we investigate how collapsed, globular chain conformations in the initial stages of structure formation, which are produced by spray-coating, affect the single-chain structure and morphology of microphase-separated multiblock copolymers. Comparing spray-coated films with films that start from a disordered state of Gaussian chains, we observe that the collapsed molecular conformations in the initial stage give rise to (1) a smaller fraction of blocks that straddle domains (bridges), (2) a significant reduction of the molecular extension normal to the internal interfaces, and (3) a slightly larger lamellar domain spacing in the final morphology. The relaxation of molecular conformations towards equilibrium is very protracted for both processes - solvent casting and spray coating. These findings illustrate that the process conditions of the copolymer materials may significantly affect materials properties (such as mechanical properties) because the system does not reach thermal equilibrium on the relevant time scales.

  2. LLNL casting technology

    SciTech Connect

    Shapiro, A.B.; Comfort, W.J. III

    1994-01-01

    Competition to produce cast parts of higher quality, lower rejection rate, and lower cost is a fundamental factor in the global economy. To gain an edge on foreign competitors, the US casting industry must cut manufacturing costs and reduce the time from design to market. Casting research and development (R&D) are the key to increasing US compentiveness in the casting arena. Lawrence Livermore National Laboratory (LLNL) is the home of a wide range of R&D projects that push the boundaries of state-of-the art casting. LLNL casting expertise and technology include: casting modeling research and development, including numerical simulation of fluid flow, heat transfer, reaction/solidification kinetics, and part distortion with residual stresses; special facilities to cast toxic material; extensive experience casting metals and nonmetals; advanced measurement and instrumentation systems. Department of Energy (DOE) funding provides the leverage for LLNL to collaborate with industrial partners to share this advanced casting expertise and technology. At the same time, collaboration with industrial partners provides LLNL technologists with broader insights into casting industry issues, casting process data, and the collective, experience of industry experts. Casting R&D is also an excellent example of dual-use technology; it is the cornerstone for increasing US industrial competitiveness and minimizing waste nuclear material in weapon component production. Annual funding for casting projects at LLNL is $10M, which represents 1% of the total LLNL budget. Metal casting accounts for about 80% of the funding. Funding is nearly equally divided between development directed toward US industrial competitiveness and weapon component casting.

  3. LLNL casting technology

    NASA Astrophysics Data System (ADS)

    Shapiro, A. B.; Comfort, W. J., III

    1994-01-01

    Competition to produce cast parts of higher quality, lower rejection rate, and lower cost is a fundamental factor in the global economy. To gain an edge on foreign competitors, the US casting industry must cut manufacturing costs and reduce the time from design to market. Casting research and development (R&D) are the key to increasing US competiveness in the casting arena. Lawrence Livermore National Laboratory (LLNL) is the home of a wide range of R&D projects that push the boundaries of state-of-the art casting. LLNL casting expertise and technology include: casting modeling research and development, including numerical simulation of fluid flow, heat transfer, reaction/solidification kinetics, and part distortion with residual stresses; special facilities to cast toxic material; extensive experience casting metals and nonmetals; advanced measurement and instrumentation systems. Department of Energy (DOE) funding provides the leverage for LLNL to collaborate with industrial partners to share this advanced casting expertise and technology. At the same time, collaboration with industrial partners provides LLNL technologists with broader insights into casting industry issues, casting process data, and the collective experience of industry experts. Casting R&D is also an excellent example of dual-use technology; it is the cornerstone for increasing US industrial competitiveness and minimizing waste nuclear material in weapon component production. Annual funding for casting projects at LLNL is $10M, which represents 1% of the total LLNL budget. Metal casting accounts for about 80% of the funding. Funding is nearly equally divided between development directed toward US industrial competitiveness and weapon component casting.

  4. Case studies of chilled water storage

    SciTech Connect

    Andrepont, J.S. )

    1993-01-01

    Centralized chilled water systems are commonly used to meet the air conditioning needs of colleges, universities, medical complexes, and other large campuses or district cooling facilities. Data from the Association of Higher Education Facilities Officers (APPA) indicate that over half its members operate central cooling plants. Various configurations are in use, including single and multiple central chilling plants serving single distribution systems, nonconnected miniature central systems, and combinations of one central and one or more satellite plants on a single distribution loop. Central plant chillers may be electric motor-driven centrifugal compressors, gas engine-driven centrifugal compressors, steam turbine-driven centrifugal compressors, heat-driven absorption chillers, or combinations of these types. The usual refrigerants are chlorofluorocarbons (CFCs); but alternatives such as HCFCs, HFCs, ammonia (NH[sub 3]), and absorption solutions may also be employed. Free cooling via cooling towers is sometimes used, directly or indirectly, during periods of relatively low ambient air temperatures. During any central plant capacity expansion, O and M, capital, and life cycle costs are among the major concerns, as are the increasingly critical issues of reliability, flexibility, safety, and the environment. Specifically, atmospheric ozone depletion and the CFC refrigerant issue are now impacting everyone involved in the air conditioning field. Anyone selecting or planning for new chiller capacity is faced with choosing from such options as CFCs, HCFCs, HFCs, ammonia, and absorption refrigeration. These choices have unique and serious drawbacks. Because of this chilled water storage is now experiencing increased application.

  5. Grain refinement of DC cast magnesium alloys with intensive melt shearing

    NASA Astrophysics Data System (ADS)

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

    2012-01-01

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

  6. Predictive Capabilities of Multiphysics and Multiscale Models in Modeling Solidification of Steel Ingots and DC Casting of Aluminum

    NASA Astrophysics Data System (ADS)

    Combeau, Hervé; Založnik, Miha; Bedel, Marie

    2016-08-01

    Prediction of solidification defects, such as macrosegregation and inhomogeneous microstructures, constitutes a key issue for industry. The development of models of casting processes needs to account for several imbricated length scales and different physical phenomena. For example, the kinetics of the growth of microstructures needs to be coupled with the multiphase flow at the process scale. We introduce such a state-of-the-art model and outline its principles. We present the most recent applications of the model to casting of a heavy steel ingot and to direct chill casting of a large Al alloy sheet ingot. Their ability to help in the understanding of complex phenomena, such as the competition between nucleation and growth of grains in the presence of convection of the liquid and of grain motion is shown, and its predictive capabilities are discussed. Key issues for future developments and research are addressed.

  7. Predictive Capabilities of Multiphysics and Multiscale Models in Modeling Solidification of Steel Ingots and DC Casting of Aluminum

    NASA Astrophysics Data System (ADS)

    Combeau, Hervé; Založnik, Miha; Bedel, Marie

    2016-06-01

    Prediction of solidification defects, such as macrosegregation and inhomogeneous microstructures, constitutes a key issue for industry. The development of models of casting processes needs to account for several imbricated length scales and different physical phenomena. For example, the kinetics of the growth of microstructures needs to be coupled with the multiphase flow at the process scale. We introduce such a state-of-the-art model and outline its principles. We present the most recent applications of the model to casting of a heavy steel ingot and to direct chill casting of a large Al alloy sheet ingot. Their ability to help in the understanding of complex phenomena, such as the competition between nucleation and growth of grains in the presence of convection of the liquid and of grain motion is shown, and its predictive capabilities are discussed. Key issues for future developments and research are addressed.

  8. Directional solidification of flake and nodular cast iron during KC-135 low-g maneuvers

    NASA Technical Reports Server (NTRS)

    Curreri, P. A.; Stefanescu, D. M.; Hendrix, J. C.

    1984-01-01

    Alloys solidified in a low-gravity environment can, due to the elimination of sedimentation and convection, form unique and often desirable microstructures. One method of studying the effects of low-gravity (low-g) on alloy solidification was the use of the NASA KC-135 aircraft flying repetitive low-g maneuvers. Each maneuver gives from 20 to 30 seconds of low-g which is between about 0.1 and 0.001 gravity. A directional solidification furnace was used to study the behavior of off eutectic composition case irons in a low-g environment. The solidification interface of hypereutectic flake and spheroidal graphite case irons was slowly advanced through a rod sample, 5 mm in diameter. Controlled solidification was continued through a number of aircraft parabolas. The known solidification rate of the sample was then correlated with accelerometer data to determine the gravity level during solidification for any location of the sample. The thermal gradient and solidification rate were controlled independently. Samples run on the KC-135 aircraft exhibited bands of coarser graphite or of larger nodules usually corresponding to the regions solidified under low-g. Samples containing high phosphorous (used in order to determine the eutectic cell) exhibited larger eutectic cells in the low-g zone, followed by a band of coarser graphite.

  9. Molecular basis of chill resistance adaptations in poikilothermic animals.

    PubMed

    Hayward, Scott A L; Manso, Bruno; Cossins, Andrew R

    2014-01-01

    Chill and freeze represent very different components of low temperature stress. Whilst the principal mechanisms of tissue damage and of acquired protection from freeze-induced effects are reasonably well established, those for chill damage and protection are not. Non-freeze cold exposure (i.e. chill) can lead to serious disruption to normal life processes, including disruption to energy metabolism, loss of membrane perm-selectivity and collapse of ion gradients, as well as loss of neuromuscular coordination. If the primary lesions are not relieved then the progressive functional debilitation can lead to death. Thus, identifying the underpinning molecular lesions can point to the means of building resistance to subsequent chill exposures. Researchers have focused on four specific lesions: (i) failure of neuromuscular coordination, (ii) perturbation of bio-membrane structure and adaptations due to altered lipid composition, (iii) protein unfolding, which might be mitigated by the induced expression of compatible osmolytes acting as 'chemical chaperones', (iv) or the induced expression of protein chaperones along with the suppression of general protein synthesis. Progress in all these potential mechanisms has been ongoing but not substantial, due in part to an over-reliance on straightforward correlative approaches. Also, few studies have intervened by adoption of single gene ablation, which provides much more direct and compelling evidence for the role of specific genes, and thus processes, in adaptive phenotypes. Another difficulty is the existence of multiple mechanisms, which often act together, thus resulting in compensatory responses to gene manipulations, which may potentially mask disruptive effects on the chill tolerance phenotype. Consequently, there is little direct evidence of the underpinning regulatory mechanisms leading to induced resistance to chill injury. Here, we review recent advances mainly in lower vertebrates and in arthropods, but increasingly

  10. Ice bubbles confirm big chill

    SciTech Connect

    Kerr, R.A.

    1996-06-14

    Clues buried in Greenland`s icesheet indicate that during the last ice age, the climate repeatedly warmed sharply, only to slide into a renewed chill lasting thousands of years. New indicators derived from trapped bubbles of ancient gases, nitrogen and methane, indicate that these were indeed catastrophic events. This article describes the research and adjunct issues.

  11. Chilled storage of foods - principles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chilled storage is the most common method for preserving perishable foods. The consumers’ increasing demand for convenient, minimally processed foods has caused food manufacturers to increase production of refrigerated foods worldwide. This book chapter reviews the development of using low tempera...

  12. Oscillator for continuous casting mold

    SciTech Connect

    Behrends, G.

    1993-06-15

    In a continuous casting machine comprising a chilled mold disposed to receive molten metal which is discharged from the mold as a curved casting having a predetermined casting radius, and an oscillating drive for oscillating the mold relative to the casting, wherein the improvement described comprises mold guidance means having a first tensile element having an inner end and an outer end, the outer end being anchored to a fixed external frame and the inner end being secured to move with the mold, the first tensile element lying on a first radius extending from the center of curvature of said pre-determined casting radius; and a second tensile element having an inner and an outer end both anchored to a fixed external frame and secured to move with the mold intermediate the inner and outer ends, at least one end having variable tensioning means adapted to apply a tensile force to the second tensile element, the second tensile element lying on a second radius extending from the center of curvature of said predetermined casting radius.

  13. Minimization of Macrosegregation in DC Cast Ingots Through Jet Processing

    NASA Astrophysics Data System (ADS)

    Wagstaff, Samuel R.; Allanore, Antoine

    2016-10-01

    With an increase in demand for aluminum alloys, industrial suppliers are seeking to increase the size and speed of casting processes. Unfortunately operating the existing Direct-Chill (DC) process in such conditions tends to enhance metallurgical defects. Perhaps the most recognized of these defects is macrosegregation, whose effects are permanent once the material is solidified. In order to facilitate the expansion of the DC process without increasing the presence of macrosegregation, a novel jet mixing method to distribute the liquid metal is presented. The governing equations for this process are derived and the operating parameters necessary to minimize the centerline macrosegregation are predicted. The results of commercial-scale tests are presented, validating the predictive equations and performance of this process.

  14. Minimization of Macrosegregation in DC Cast Ingots Through Jet Processing

    NASA Astrophysics Data System (ADS)

    Wagstaff, Samuel R.; Allanore, Antoine

    2016-06-01

    With an increase in demand for aluminum alloys, industrial suppliers are seeking to increase the size and speed of casting processes. Unfortunately operating the existing Direct-Chill (DC) process in such conditions tends to enhance metallurgical defects. Perhaps the most recognized of these defects is macrosegregation, whose effects are permanent once the material is solidified. In order to facilitate the expansion of the DC process without increasing the presence of macrosegregation, a novel jet mixing method to distribute the liquid metal is presented. The governing equations for this process are derived and the operating parameters necessary to minimize the centerline macrosegregation are predicted. The results of commercial-scale tests are presented, validating the predictive equations and performance of this process.

  15. Semi-quantitative predictions of hot tearing and cold cracking in aluminum DC casting using numerical process simulator

    NASA Astrophysics Data System (ADS)

    Subroto, T.; Miroux, A.; Mortensen, D.; M'Hamdi, M.; Eskin, D. G.; Katgerman, L.

    2012-07-01

    Cracking is one of the most critical defects that may occur during aluminum direct-chill (DC) casting. There are two types of cracking typical of DC casting: hot tearing and cold cracking. To study and predict such defects, currently we are using a process simulator, ALSIM. ALSIM is able to provide semi-quantitative predictions of hot tearing and cold cracking susceptibility. In this work, we performed benchmark tests using predictions of both types of cracks and experimental results of DC casting trials. The trials series resulted in billets with hot tearing as well as cold cracking. The model was also used to study the influence of several casting variables such as casting speed and inlet geometry with respect to the cracking susceptibility in the ingots. In this work, we found that the sump geometry was changed by the feeding scheme, which played an important role in hot tear occurrence. Moreover, increasing the casting speed also increased the hot tear and cold crack susceptibility. In addition, from the result of simulation, we also observed a phenomenon that supported the hypotheses of connection between hot tearing and cold cracking.

  16. 1991: Warmth, chill may follow

    SciTech Connect

    Kerr, R.A.

    1992-01-17

    Following 1990's record temperatures, last year ended as the second warmest ever recorded. But it might have set yet another record had it not been for the eruption of Mount Pinatubo. The layer of sun-blocking haze spewed by the Philippine volcano is sending a chill through the climate system that may already have shown up in the temperature record. This volcanic cooling, which could last a couple of years, should also temporarily chill the debate about whether the green house effect is behind the warming of recent years. It's been hard enough to draw firm conclusions about any greenhouse warming from world temperature data, and Pinatubo's masking effect should make it harder still during the next few years. But the cooling episode may advance the science of climate prediction indirectly. It will give scientists an opportunity to check out their computer greenhouse models by seeing how well they do at predicting the volcano-induced climate change.

  17. High coercivity microcrystalline Nd-rich Nd-Fe-Co-Al-B bulk magnets prepared by direct copper mold casting

    NASA Astrophysics Data System (ADS)

    Zhao, L. Z.; Hong, Y.; Fang, X. G.; Qiu, Z. G.; Zhong, X. C.; Gao, X. S.; Liu, Z. W.

    2016-06-01

    High coercivity Nd25Fe40Co20Al15-xBx (x=7-15) hard magnets were prepared by a simple process of injection casting. Different from many previous investigations on nanocomposite compositions, the magnets in this work contain hard magnetic Nd2(FeCoAl)14B, Nd-rich, and Nd1+ε(FeCo)4B4 phases. The magnetic properties, phase evolution, and microstructure of the as-cast and annealed magnets were investigated. As the boron content increased from 7 to 11 at%, the intrinsic coercivity Hcj of the as-cast magnet increased from 816 to 1140 kA/m. The magnets annealed at 750 °C have shown more regular and smaller grains than the as-cast alloys, especially for the x=11 alloy. The high intrinsic coercivities for the annealed alloys with x=8~11 result from the presence of small-sized grains in the microstructure. The highest Hcj of 1427 kA/m was obtained for the heat treated alloy with x=10. This work provides an alternative approach for preparing fully dense Nd-rich bulk hard magnets with relatively good properties.

  18. Mechanism of Inhibition of Translocation by Localized Chilling 1

    PubMed Central

    Giaquinta, R. T.; Geiger, D. R.

    1973-01-01

    Arrhenius plots of translocation velocity as a function of petiole temperature show a marked increase in temperature dependence below 10 C in bean (a chilling-sensitive species) but not in sugar beet (chilling-resistant). The increased temperature dependence below 10 C was not observed for cytoplasmic streaming or oxygen uptake in bean. Bean petioles were served to release pressure in order to determine whether sieve tubes are obstructed in cold-treated petioles. The resulting pressure release caused serious displacement of the crystalline protein bodies in the sieve tubes of petioles at 25 C, but in those locally cooled to 0 C for 30 minutes little displacement occurred, indicating obstruction in the latter. An ultrastructural study of sieve tubes in tissue frozen rapidly in situ and dehydrated by freeze substitution revealed that treatment at 0 C for 30 minutes caused structural alteration and displacement of the cytoplasmic material lining the sieve tube wall resulting in occlusion of sieve plates. The sieve plates of the control petioles at 25 C were generally clear of obstructions. The results indicate that inhibition of translocation by chilling in chilling-sensitive plants results from physical blockage of sieve plates rather than from direct inhibition of a metabolic process which drives translocation. Images PMID:16658332

  19. Chloroplast RNA-Binding Protein RBD1 Promotes Chilling Tolerance through 23S rRNA Processing in Arabidopsis

    PubMed Central

    Yang, Leiyun; Yang, Fen; Wang, Yi; Zhu, Jian-Kang; Hua, Jian

    2016-01-01

    Plants have varying abilities to tolerate chilling (low but not freezing temperatures), and it is largely unknown how plants such as Arabidopsis thaliana achieve chilling tolerance. Here, we describe a genome-wide screen for genes important for chilling tolerance by their putative knockout mutants in Arabidopsis thaliana. Out of 11,000 T-DNA insertion mutant lines representing half of the genome, 54 lines associated with disruption of 49 genes had a drastic chilling sensitive phenotype. Sixteen of these genes encode proteins with chloroplast localization, suggesting a critical role of chloroplast function in chilling tolerance. Study of one of these proteins RBD1 with an RNA binding domain further reveals the importance of chloroplast translation in chilling tolerance. RBD1 is expressed in the green tissues and is localized in the chloroplast nucleoid. It binds directly to 23S rRNA and the binding is stronger under chilling than at normal growth temperatures. The rbd1 mutants are defective in generating mature 23S rRNAs and deficient in chloroplast protein synthesis especially under chilling conditions. Together, our study identifies RBD1 as a regulator of 23S rRNA processing and reveals the importance of chloroplast function especially protein translation in chilling tolerance. PMID:27138552

  20. Chloroplast RNA-Binding Protein RBD1 Promotes Chilling Tolerance through 23S rRNA Processing in Arabidopsis.

    PubMed

    Wang, Shuai; Bai, Ge; Wang, Shu; Yang, Leiyun; Yang, Fen; Wang, Yi; Zhu, Jian-Kang; Hua, Jian

    2016-05-01

    Plants have varying abilities to tolerate chilling (low but not freezing temperatures), and it is largely unknown how plants such as Arabidopsis thaliana achieve chilling tolerance. Here, we describe a genome-wide screen for genes important for chilling tolerance by their putative knockout mutants in Arabidopsis thaliana. Out of 11,000 T-DNA insertion mutant lines representing half of the genome, 54 lines associated with disruption of 49 genes had a drastic chilling sensitive phenotype. Sixteen of these genes encode proteins with chloroplast localization, suggesting a critical role of chloroplast function in chilling tolerance. Study of one of these proteins RBD1 with an RNA binding domain further reveals the importance of chloroplast translation in chilling tolerance. RBD1 is expressed in the green tissues and is localized in the chloroplast nucleoid. It binds directly to 23S rRNA and the binding is stronger under chilling than at normal growth temperatures. The rbd1 mutants are defective in generating mature 23S rRNAs and deficient in chloroplast protein synthesis especially under chilling conditions. Together, our study identifies RBD1 as a regulator of 23S rRNA processing and reveals the importance of chloroplast function especially protein translation in chilling tolerance. PMID:27138552

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

    SciTech Connect

    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

  2. Technical development of double-clad process for thin strip casting of carbon steel

    SciTech Connect

    Brown, H.L.; Forkel, C.E.; Knudson, D.L.

    1984-08-01

    This report documents the technical development for a patent disclosure of a double-clad process for the continuous casting of thin-strip carbon steel. The fundamental idea of the disclosure is to form a product strip by depositing molten steel between two, cooled, clad strips of the same material. The claimed benefits include: (a) the conservation of energy in steel making through the elimination of soaking pits and reheat cycles, and (b) an improved surface on both sides of the as-cast product such that it will be suitable for direct feed to a cold-reduction mill. However, the process as conceived is not necessarily limited to the casting of carbon steel, but may be also applied to other metals and alloys. The work is described under three headings as follows. Preliminary Considerations and Scoping Analysis presents the basic idea of the double-clad, thin-strip casting process; the energy conservation potential; scoping heat transfer calculations for the casting process; and independent review of this work. Thermal Analysis for Roller Configuration of Double-Clad Process, presents the development, results, and independent review of a finite-element thermal analysis for the casting process as originally conceived (using only chilled rollers in direct contact with the clad material of the product strip). Further Considerations for Belt Configuration of Double-Clad Process deals with a modified equipment design which interposes two product support belts, one on each side of the product, between the clad strip and the rollers. In addition to the process description, this section presents the preliminary mechanical calculations for the endless metal belts and the work scope and results for the computer model revision and thermal analysis for the modified concept.

  3. Hygiene aspects of modern poultry chilling.

    PubMed

    Allen, V M; Corry, J E; Burton, C H; Whyte, R T; Mead, G C

    2000-06-30

    An evaluation was made of six commercial poultry chilling systems in relation to factors affecting microbial-contamination of carcasses. These systems included water immersion chilling, air chilling and air chilling with evaporative cooling using water sprays. Samples of neck skin and body cavity were taken from carcasses, together with samples from the chilling environment. These were examined for total aerobic mesophilic microbes and counts of presumptive coliform bacteria and Pseudomonas spp. at specific points in the chilling process. Physical measurements included surface and deep-muscle temperatures of carcasses, water temperatures and chlorine concentrations in the immersion system and air speed and temperature during air chilling. The results obtained for water immersion chilling confirmed previous experience that the washing effect reduces microbial contamination of carcasses, although initially the numbers of pseudomonads tended to increase. The air chillers varied in design and mode of operation, but had little overall effect on microbial contamination of the skin. When a completely dry process was used, microbial numbers were reduced approximately ten-fold in the body cavity. However, the use of water sprays tended to increase contamination of the cavity, while relatively heavy spraying using non-chlorinated water, resulted in a substantial increase in the numbers of pseudomonads.

  4. 21 CFR 890.5940 - Chilling unit.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Chilling unit. 890.5940 Section 890.5940 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5940 Chilling unit....

  5. 21 CFR 890.5940 - Chilling unit.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Chilling unit. 890.5940 Section 890.5940 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5940 Chilling unit....

  6. 21 CFR 890.5940 - Chilling unit.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Chilling unit. 890.5940 Section 890.5940 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5940 Chilling unit....

  7. 21 CFR 890.5940 - Chilling unit.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Chilling unit. 890.5940 Section 890.5940 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5940 Chilling unit....

  8. 21 CFR 890.5940 - Chilling unit.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Chilling unit. 890.5940 Section 890.5940 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5940 Chilling unit....

  9. Modelling of stress fields during LFEM DC casting of aluminium billets by a meshless method

    NASA Astrophysics Data System (ADS)

    Mavrič, B.; Šarler, B.

    2015-06-01

    Direct Chill (DC) casting of aluminium alloys is a widely established technology for efficient production of aluminium billets and slabs. The procedure is being further improved by the application of Low Frequency Electromagnetic Field (LFEM) in the area of the mold. Novel LFEM DC processing technique affects many different phenomena which occur during solidification, one of them being the stresses and deformations present in the billet. These quantities can have a significant effect on the quality of the cast piece, since they impact porosity, hot-tearing and cold cracking. In this contribution a novel local radial basis function collocation method (LRBFCM) is successfully applied to the problem of stress field calculation during the stationary state of DC casting of aluminium alloys. The formulation of the method is presented in detail, followed by the presentation of the tackled physical problem. The model describes the deformations of linearly elastic, inhomogeneous isotropic solid with a given temperature field. The temperature profile is calculated using the in-house developed heat and mass transfer model. The effects of low frequency EM casting process parameters on the vertical, circumferential and radial stress and on the deformation of billet surface are presented. The application of the LFEM appears to decrease the amplitudes of the tensile stress occurring in the billet.

  10. Chill block melt spinning of nickel-molybdenum alloys

    NASA Technical Reports Server (NTRS)

    Hemker, Kevin J.; Glasgow, Thomas K.

    1987-01-01

    Samples of Ni-Mo alloys ranging in composition from pure nickel to Ni-40 at. pct molybdenum were cast by the chill block melt-spinning rapid solidification technique and examined by optical metallography, X-ray diffraction, and microhardness testing. Casting difficulties were encountered with lean alloys, but richer alloys spread more readily on the casting wheel. Alloy microstructures for 5 to 37.5 at. pct molybdenum ribbons were primarily cellular/dendritic; microstructure feature size decreased with increasing molybdenum content. Extended solubility of molybdenum in gamma-nickel, with fcc lattice parameter increasing with composition to the 1.05 power, was observed up to 37/5 at. pct molybdenum. Substoichiometric Ni-Mo (delta) nucleated on the wheel side of the ribbons of compositions 35, 37.5, and 40 at. pct molybdenum. The amount of partitionless delta-phase thus formed increased with increasing molybdenum content and quench rate. This substoichiometric delta transformed readily to a fine structure gamma-delta mixture.

  11. Preparation and characterization of microparticles of piroxicam by spray drying and spray chilling methods

    PubMed Central

    Dixit, M.; Kini, A.G.; Kulkarni, P.K.

    2010-01-01

    Piroxicam, an anti-inflammatory drug, exhibits poor water solubility and flow properties, poor dissolution and poor wetting. Consequently, the aim of this study was to improve the dissolution of piroxicam. Microparticles containing piroxicam were produced by spray drying, using isopropyl alcohol and water in the ratio of 40:60 v/v as solvent system, and spray chilling technology by melting the drug and chilling it with a pneumatic nozzle to enhance dissolution rate. The prepared formulations were evaluated for in vitro dissolution and solubility. The prepared drug particles were characterized by scanning electron microscopy (SEM), differential scanning calorimeter, X-ray diffraction and Fourier transform infrared spectroscopy. Dissolution profile of the spray dried microparticles was compared with spray-chilled microparticles, pure and recrystallized samples. Spray dried microparticles and spray chilled microparticles exhibited decreased crystallinity and improved micromeritic properties. The dissolution of the spray dried microparticle and spray chilled particles were improved compared with recrystallized and pure sample of piroxicam. Consequently, it was believed that spray drying of piroxicam is a useful tool to improve dissolution but not in case of spray chilling. This may be due to the degradation of drug or variations in the resonance structure or could be due to minor distortion of bond angles. Hence, this spray drying technique can be used for formulation of tablets of piroxicam by direct compression with directly compressible tablet excipients. PMID:21589797

  12. Chills

    MedlinePlus

    ... include: Dress the child in light clothing, provide liquids, and keep the room cool but not uncomfortable. DO NOT use ice water or rubbing alcohol baths to reduce a child's temperature. These can cause shivering and even shock . DO ...

  13. Filler metal alloy for welding cast nickel aluminide alloys

    DOEpatents

    Santella, M.L.; Sikka, V.K.

    1998-03-10

    A filler metal alloy used as a filler for welding cast nickel aluminide alloys contains from about 15 to about 17 wt. % chromium, from about 4 to about 5 wt. % aluminum, equal to or less than about 1.5 wt. % molybdenum, from about 1 to about 4.5 wt. % zirconium, equal to or less than about 0.01 wt. % yttrium, equal to or less than about 0.01 wt. % boron and the balance nickel. The filler metal alloy is made by melting and casting techniques such as are melting the components of the filler metal alloy and cast in copper chill molds. 3 figs.

  14. Study of Grain-Growth Kinetics in Delta-Ferrite and Austenite with Application to Thin-Slab Cast Direct-Rolling Microalloyed Steels

    NASA Astrophysics Data System (ADS)

    Zhou, Tihe; O'Malley, Ronald J.; Zurob, Hatem S.

    2010-08-01

    The high-temperature grain-growth kinetics in delta-ferrite and austenite is investigated. The delta-ferrite growth kinetics was observed directly on a model alloy that contained 2.5 wt pct aluminum in order to stabilize delta-ferrite down to room temperature. The gamma grain-growth kinetics was by etching the former austenite grain boundaries in a precipitate-free variant of APIX60 steel. At high temperatures and in the absence of precipitation, the growth kinetics in both delta-ferrite and austenite appeared to follow a simple parabolic growth law. The findings are applied to the problem of grain-size control during the process of thin-slab casting direct rolling (TSCDR).

  15. In situ purification, alloying and casting methodology for metallic plutonium

    NASA Astrophysics Data System (ADS)

    Lashley, Jason C.; Blau, Michael S.; Staudhammer, Karl P.; Pereyra, Ramiro A.

    Plutonium metal that has been double ER (electrorefined/electrorefining) was further purified via zone refining, using a floating molten zone to minimize the introduction of impurities. The temperature of the molten zone was 750°C, and the atmosphere was 10 -5 Pa. A total of ten zone refining passes were made at a travel rate of 1.5 cm/h. There were 19 elements reduced to quantities below the minimum detectable limits (MDL) by zone refining, while P, K, and W were significantly reduced. The zone-refined metal was then used in an in situ distillation, alloying, and casting step to prepare tapered specimens for single-crystal growth experiments. Specifically, 241Am was distilled from Pu metal by levitating Pu metal with 1 wt% Ga in the melt in a Crystallox vertical electromagnetic levitation crucible at 10 -5 Pa. The Pu is alloyed with Ga to stabilize the δ phase (fcc symmetry) upon solidification. The Pu was chill-cast directly from the electromagnetic levitation field into 1- cm tapered specimens. A water-cooled ceramic mold was used, and the Pu metal was cooled at a rate of 100°C/min. A microstructure examination of the specimen showed 10 × 25 μm acicular grains with a density of 15.938 g/cm 3 (±0.002 g/cm 3).

  16. Influence of Cr and W alloying on the fiber-matrix interfacial shear strength in cast and directionally solidified sapphire NiAl composites

    NASA Technical Reports Server (NTRS)

    Asthana, R.; Tiwari, R.; Tewari, S. N.

    1995-01-01

    Sapphire-reinforced NiAl matrix composites with chromium or tungsten as alloying additions were synthesized using casting and zone directional solidification (DS) techniques and characterized by a fiber pushout test as well as by microhardness measurements. The sapphire-NiAl(Cr) specimens exhibited an interlayer of Cr rich eutectic at the fiber-matrix interface and a higher interfacial shear strength compared to unalloyed sapphire-NiAl specimens processed under identical conditions. In contrast, the sapphire-NiAl(W) specimens did not show interfacial excess of tungsten rich phases, although the interfacial shear strength was high and comparable to that of sapphire-NiAl(Cr). The postdebond sliding stress was higher in sapphire-NiAl(Cr) than in sapphire-NiAl(W) due to interface enrichment with chromium particles. The matrix microhardness progressively decreased with increasing distance from the interface in both DS NiAl and NiAl(Cr) specimens. The study highlights the potential of casting and DS techniques to improve the toughness and strength of NiAl by designing dual-phase microstructures in NiAl alloys reinforced with sapphire fibers.

  17. Some Metallurgical Issues Concerning Austenite Conditioning in Nb-Ti and Nb-Mo Microalloyed Steels Processed by Near-Net-Shape Casting and Direct Rolling Technologies

    NASA Astrophysics Data System (ADS)

    López, Beatriz; Rodriguez-Ibabe, Jose M.

    2016-08-01

    As thin slab direct rolling technologies are moving to the production of higher quality steel grades, chemical compositions based on Nb-Ti and Nb-Mo become a good option. However, with the use of multiple microalloying additions, the as-cast austenite conditioning becomes more complex. This paper analyzes some of the microstructural features that should be taken into account during the as-cast austenite conditioning in Nb-Ti and Nb-Mo microalloyed steel grades. In the case of Nb-Ti grades, it has been observed that the process parameters during solidification and post-solidification steps affect the austenite evolution during hot rolling. This is due to the differences in the size and volume fraction of TiN particles that can be formed. Fine TiN precipitates have been shown to be able to delay recrystallization kinetics. Moreover, the solute drag effect of Ti cannot be ignored in the case of hyperstoichiometric Ti/N ratios. It is observed that Nb-Ti grades tend to have lower non-recrystallization temperatures compared to Nb grades, which means that pancaking of the austenite is more difficult for these steels. The opposite is observed for the Nb-Mo grades, although in both cases the behavior is affected by the nominal content of Nb.

  18. Casting larger polycrystalline silicon ingots

    SciTech Connect

    Wohlgemuth, J.; Tomlinson, T.; Cliber, J.; Shea, S.; Narayanan, M.

    1995-08-01

    Solarex has developed and patented a directional solidification casting process specifically designed for photovoltaics. In this process, silicon feedstock is melted in a ceramic crucible and solidified into a large grained semicrystalline silicon ingot. In-house manufacture of low cost, high purity ceramics is a key to the low cost fabrication of Solarex polycrystalline wafers. The casting process is performed in Solarex designed casting stations. The casting operation is computer controlled. There are no moving parts (except for the loading and unloading) so the growth process proceeds with virtually no operator intervention Today Solarex casting stations are used to produce ingots from which 4 bricks, each 11.4 cm by 11.4 cm in cross section, are cut. The stations themselves are physically capable of holding larger ingots, that would yield either: 4 bricks, 15 cm by 15 an; or 9 bricks, 11.4 cm by 11.4 an in cross-section. One of the tasks in the Solarex Cast Polycrystalline Silicon PVMaT Program is to design and modify one of the castings stations to cast these larger ingots. If successful, this effort will increase the production capacity of Solarex`s casting stations by 73% and reduce the labor content for casting by an equivalent percentage.

  19. Pigmented casts.

    PubMed

    Miteva, Mariya; Romanelli, Paolo; Tosti, Antonella

    2014-01-01

    Pigmented casts have been reported with variable frequency in scalp biopsies from alopecia areata, trichotillomania, chemotherapy-induced alopecia and postoperative (pressure induced) alopecia. Their presence and morphology in other scalp disorders has not been described. The authors assessed for the presence and morphology of pigmented casts in 308 transversely bisected scalp biopsies from nonscarring and scarring alopecia, referred to the Department of Dermatology, University of Miami within a year. The pigmented casts were present in 21 of 29 cases of alopecia areata (72%), 7 of 7 cases of trichotillomania (100%), 1 case of friction alopecia, 4 of 28 cases of central centrifugal cicatricial alopecia (14%), and 4 of 4 cases of dissecting cellulitis (100%). They did not show any distinguishing features except for the morphology in trichotillomania, which included twisted, linear (zip), and "button"-like pigment aggregation. The linear arrangement was found also in friction alopecia and dissecting cellulitis. Pigmented casts in the hair canals of miniaturized/vellus hairs was a clue to alopecia areata. Pigmented casts can be observed in biopsies of different hair disorders, but they are not specific for the diagnosis. Horizontal sections allow to better assess their morphology and the follicular level of presence of pigmented casts, which in the context of the other follicular findings may be a clue to the diagnosis. PMID:23823025

  20. Constitutive behaviour of an as-cast AA7050 alloy in the sub-solidus temperature range

    NASA Astrophysics Data System (ADS)

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

    2012-01-01

    Aluminum alloy 7050 is of interest for aerospace industries due to its superior mechanical properties. However, its inherent solidification behaviour may augment the accumulation of residual stresses due to uneven cooling conditions upon direct-chill (DC) casting. This can increase the propensity of cold cracking (CC), which is a potentially catastrophic phenomenon in casting ingots. To predict the outcome of the aluminum casting process, ALSIM software is utilised. This software has the capability to predict CC susceptibility during the casting process. However, at the moment, ALSIM lacks the information regarding material constitutive behaviour in the sub-solidus temperature range, which is considered important for studying CC phenomenon. At the moment, ALSIM only has a partial constitutive database for AA7050 and misses data, especially in the vicinity of non-equilibrium solidus (NES) point. The present work presents measurements of tensile constitutive parameters in the temperature range between 400 °C and NES, which is for this alloy defined as 465 °C. The mechanical behaviour is tested in a Gleeble 3800 thermo-mechanical simulator. Constitutive parameters such as stress-strain curves, strain-rate sensitivity and ductility of the alloy have been measured at different test temperatures. With these constitutive data, we expect to improve the accuracy of ALSIM simulations in terms of CC prediction, and gain more insight into the evolution of mechanical properties of AA7050 in the temperature nearby the NES.

  1. Finite Element Modelling of the Sawing of DC Cast AA2024 Aluminium Alloy Slabs

    NASA Astrophysics Data System (ADS)

    Drezet, J.-M.; Ludwig, O.; Heinrich, B.

    2007-04-01

    In the semi-continuous casting of large cross-section rolling sheet ingots of high-strength aluminum alloys (2xxx and 7xxx series), the control of the residual (internal) stresses generated by the non-uniform cooling becomes a necessity. These stresses must be relieved by a thermal treatment before the head and foot of the ingot can be cut. Otherwise, the saw can be caught owing to compressive stresses or cut parts may be ejected thus injuring people or damaging equipment. These high added-value ingots need to be produced in secure conditions. Moreover, a better control of the sawing procedure could allow the suppression of the thermal treatment and therefore save time and energy. By studying the stress build-up during casting and the stress relief during sawing, key parameters for the control and optimization of the processing steps, can be derived. To do so, the direct chill (DC) casting of the AA2024 alloy is modeled with ABAQUS 6.5 with special attention to the thermo-mechanical properties of the alloy. The sawing operation is then simulated by removing mesh elements so as to reproduce the progression of the saw in the ingot. Preliminary results showing the stress relief during sawing accompanied by the risk of saw blocking due to compression or initiating a crack ahead of the saw, are analyzed with an approach based on the rate of strain energy release.

  2. Finite Element Modelling of the Sawing of DC Cast AA2024 Aluminium Alloy Slabs

    SciTech Connect

    Drezet, J.-M.; Ludwig, O.; Heinrich, B.

    2007-04-07

    In the semi-continuous casting of large cross-section rolling sheet ingots of high-strength aluminum alloys (2xxx and 7xxx series), the control of the residual (internal) stresses generated by the non-uniform cooling becomes a necessity. These stresses must be relieved by a thermal treatment before the head and foot of the ingot can be cut. Otherwise, the saw can be caught owing to compressive stresses or cut parts may be ejected thus injuring people or damaging equipment. These high added-value ingots need to be produced in secure conditions. Moreover, a better control of the sawing procedure could allow the suppression of the thermal treatment and therefore save time and energy. By studying the stress build-up during casting and the stress relief during sawing, key parameters for the control and optimization of the processing steps, can be derived. To do so, the direct chill (DC) casting of the AA2024 alloy is modeled with ABAQUS 6.5 with special attention to the thermo-mechanical properties of the alloy. The sawing operation is then simulated by removing mesh elements so as to reproduce the progression of the saw in the ingot. Preliminary results showing the stress relief during sawing accompanied by the risk of saw blocking due to compression or initiating a crack ahead of the saw, are analyzed with an approach based on the rate of strain energy release.

  3. Residual Stresses in DC cast Aluminum Billet: Neutron Diffraction Measurements and Thermomechanical Modeling

    SciTech Connect

    Drezet, J.-M.; Evans, A.; Pirling, T.

    2011-05-04

    Thermally-induced residual stresses, generated during the industrial Direct Chill casting process of aluminum alloys, can cause both significant safety concerns as well as the formation of defects during down-stream processing. Although these thermally induced strains can be partially relieved by permanent deformation, cracks will be generated either during solidification (hot tears) or post-solidification cooling (cold cracks) when stresses exceed the deformation limit of the alloy. Furthermore, the thermally induced strains result in the presence of large internal stresses within the billet before further processing steps. Although numerical models have been previously developed to compute these residual stresses, most of the computations have been validated only against measured surface distortions. In the present work, the variation in residual elastic strains and stresses in the steady state regime of casting has been measured as a function of radial position using neutron diffraction in an AA6063 grain-refined cylindrical billet. These measurements have been carried out on the same billet section at Poldi at PSI-Villigen and at Salsa at ILL-Grenoble and compare favorably. The results are used to validate a thermo-mechanical finite element casting model and to assess the level of stored elastic energy within the billet.

  4. Residual Stresses in DC cast Aluminum Billet: Neutron Diffraction Measurements and Thermomechanical Modeling

    NASA Astrophysics Data System (ADS)

    Drezet, J.-M.; Evans, A.; Pirling, T.

    2011-05-01

    Thermally-induced residual stresses, generated during the industrial Direct Chill casting process of aluminum alloys, can cause both significant safety concerns as well as the formation of defects during down-stream processing. Although these thermally induced strains can be partially relieved by permanent deformation, cracks will be generated either during solidification (hot tears) or post-solidification cooling (cold cracks) when stresses exceed the deformation limit of the alloy. Furthermore, the thermally induced strains result in the presence of large internal stresses within the billet before further processing steps. Although numerical models have been previously developed to compute these residual stresses, most of the computations have been validated only against measured surface distortions. In the present work, the variation in residual elastic strains and stresses in the steady state regime of casting has been measured as a function of radial position using neutron diffraction in an AA6063 grain-refined cylindrical billet. These measurements have been carried out on the same billet section at Poldi at PSI-Villigen and at Salsa at ILL-Grenoble and compare favorably. The results are used to validate a thermo-mechanical finite element casting model and to assess the level of stored elastic energy within the billet.

  5. Elimination of Hot Tears in Steel Castings by Means of Solidification Pattern Optimization

    NASA Astrophysics Data System (ADS)

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

    2012-06-01

    A methodology of how to exploit the Niyama criterion for the elimination of various defects such as centerline porosity, macrosegregation, and hot tearing in steel castings is presented. The tendency of forming centerline porosity is governed by the temperature distribution close to the end of the solidification interval, specifically by thermal gradients and cooling rates. The physics behind macrosegregation and hot tears indicate that these two defects also are dependent heavily on thermal gradients and pressure drop in the mushy zone. The objective of this work is to show that by optimizing the solidification pattern, i.e., establishing directional and progressive solidification with the help of the Niyama criterion, macrosegregation and hot tearing issues can be both minimized or eliminated entirely. An original casting layout was simulated using a transient three-dimensional (3-D) thermal fluid model incorporated in a commercial simulation software package to determine potential flaws and inadequacies. Based on the initial casting process assessment, multiobjective optimization of the solidification pattern of the considered steel part followed. That is, the multiobjective optimization problem of choosing the proper riser and chill designs has been investigated using genetic algorithms while simultaneously considering their impact on centerline porosity, the macrosegregation pattern, and primarily on hot tear formation.

  6. Modeling Coal Seam Damage in Cast Blasting

    SciTech Connect

    Chung, S.H.; Preece, D.S.

    1998-11-23

    A discrete element computer program named DMC_BLAST (Distinct Motion Code) has been under development since 1987 for modeling rock blasting (Preece & Taylor, 1989). This program employs explicit time integration and uses spherical or cylindrical elements that are represented as circles in two dimensions. DMC_BLAST calculations compare favorably with data from actual bench blasts (Preece et al, 1993). Coal seam chilling refers to the shattering of a significant portion of the coal leaving unusable fines. It is also refereed to as coal damage. Chilling is caused during a blast by a combination of explosive shock energy and movement of the adjacent rock. Chilling can be minimized by leaving a buffer zone between the bottom of the blastholes and the coal seam or by changing the blast design to decrease the powder factor or by a combination of both. Blast design in coal mine cast blasting is usually a compromise between coal damage and rock fragmentation and movement (heave). In this paper the damage to coal seams from rock movement is examined using the discrete element computer code DMC_BLAST. A rock material strength option has been incorporated into DMC_BLAST by placing bonds/links between the spherical particles used to model the rock. These bonds tie the particles together but can be broken when the tensile, compressive or shear stress in the bond exceeds the defined strength. This capability has been applied to predict coal seam damage, particularly at the toe of a cast blast where drag forces exerted by movement of the overlying rock can adversely effect the top of the coal at the bench face. A simulation of coal mine cast blasting has been performed with special attention being paid to the strength of the coal and its behavior at t he bench face during movement of the overlying material.

  7. Project CAST.

    ERIC Educational Resources Information Center

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

    The document outlines procedures for implementing Project CAST (Community and School Together), a community-based career education program for secondary special education students in Charles County, Maryland. Initial sections discuss the role of a learning coordinator, (including relevant travel reimbursement and mileage forms) and an overview of…

  8. Cold-induced depolarization of insect muscle: differing roles of extracellular K+ during acute and chronic chilling.

    PubMed

    MacMillan, Heath Andrew; Findsen, Anders; Pedersen, Thomas Holm; Overgaard, Johannes

    2014-08-15

    Insects enter chill coma, a reversible state of paralysis, at temperatures below their critical thermal minimum (CTmin), and the time required for an insect to recover after a cold exposure is termed chill coma recovery time (CCRT). The CTmin and CCRT are both important metrics of insect cold tolerance that are used interchangeably, although chill coma recovery is not necessarily permitted by a direct reversal of the mechanism causing chill coma onset. Nevertheless, onset and recovery of coma have been attributed to loss of neuromuscular function due to depolarization of muscle fibre membrane potential (Vm). Here we test the hypothesis that muscle depolarization at chill coma onset and repolarization during chill coma recovery are caused by changes in extracellular [K(+)] and/or other effects of low temperature. Using Locusta migratoria, we measured in vivo muscle resting potentials of the extensor tibialis during cooling, following prolonged exposure to -2°C and during chill coma recovery, and related changes in Vm to transmembrane [K(+)] balance and temperature. Although Vm was rapidly depolarized by cooling, hemolymph [K(+)] did not rise until locusts had spent considerable time in the cold. Nonetheless, a rise in hemolymph [K(+)] during prolonged cold exposure further depressed muscle resting potential and slowed recovery from chill coma upon rewarming. Muscle resting potentials had a bimodal distribution, and with elevation of extracellular [K(+)] (but not temperature) muscle resting potentials become unimodal. Thus, a disruption of extracellular [K(+)] does depolarize muscle resting potential and slow CCRT following prolonged cold exposure. However, onset of chill coma at the CTmin relates to an as-yet-unknown effect of temperature on neuromuscular function.

  9. Vacuum-formed matrix as a guide for the fabrication of multiple direct patterns for cast posts and cores.

    PubMed

    Bluche, L R; Bluche, P F; Morgano, S M

    1997-03-01

    Fabrication of multiple posts and cores for severely damaged pulpless teeth is arduous because few landmarks remain. Esthetic requirements, occlusal relations, and long axes of the planned final restorations influence the core design. This article describes a method for directly verifying fabricated post-and-core patterns by combining the procedures for making a thermoformed shell for a preparation template and creating a plastic template for multiple core pattern fabrication.

  10. Microbiological quality of water immersion-chilled and air-chilled broilers.

    PubMed

    Zhang, Lei; Jeong, Jong Y; Janardhanan, Kishorekumar K; Ryser, Elliot T; Kang, Iksoon

    2011-09-01

    Carcass chilling during broiler processing is a critical step in preventing growth of pathogenic and spoilage bacteria. The objective of this study was to compare the microbiological quality of air- and water-chilled broiler carcasses processed at the same commercial facility. For each of four replications, 15 broilers were collected from the same commercial processing line after evisceration, after spraying with cetylpyridinium chloride (a cationic disinfectant), and after air chilling or water immersion chilling (WIC). All carcasses were quantitatively examined for mesophilic aerobic bacteria, Escherichia coli, coliforms, and Campylobacter as well as for the presence of Salmonella and Campylobacter. No significant differences (P > 0.05) were seen between air and water chilling for E. coli or coliforms or for the incidence of Salmonella and Campylobacter. Lower numbers of Campylobacter were recovered from WIC than from air-chilled carcasses (P < 0.05), but the incidence of Campylobacter on WIC carcasses was similar, suggesting that some Campylobacter organisms were injured rather than killed during WIC. In-line spraying with the disinfectant effectively decreased the incidence of Salmonella and Campylobacter on prechilled carcasses; however, cells presumably injured by the sanitizer recovered during chilling. Therefore, on-farm intervention strategies remain critically important in minimizing the spread of microbial contaminants during processing. PMID:21902923

  11. The New Wind Chill Equivalent Temperature Chart.

    NASA Astrophysics Data System (ADS)

    Osczevski, Randall; Bluestein, Maurice

    2005-10-01

    The formula used in the U.S. and Canada to express the combined effect of wind and low temperature on how cold it feels was changed in November 2001. Many had felt that the old formula for equivalent temperature, derived in the 1960s from Siple and Passel's flawed but quite useful Wind Chill Index, unnecessarily exaggerated the severity of the weather. The new formula is based on a mathematical model of heat flow from the upwind side of a head-sized cylinder moving at walking speed into the wind. The paper details the assumptions that were made in generating the new wind chill charts. It also points out weaknesses in the concept of wind chill equivalent temperature, including its steady-state character and a seemingly paradoxical effect of the internal thermal resistance of the cylinder on comfort and equivalent temperature. Some improvements and alternatives are suggested.

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

    ERIC Educational Resources Information Center

    Zebco, Tulsa, OK.

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

  13. Casting process modeling using ProCAST and CAST2D

    SciTech Connect

    Shapiro, A.; Stein, W.; Raboin, P.

    1990-12-01

    Correctly modeling the fluid flow and heat transfer during the filling of a mold with a molten metal, and the thermal-mechanical physics of solidification and cooldown is important in predicting the quality of a cast part. Determining the dynamics of the flow and the free surface shape during filling are essential in establishing the temperature gradients in the melt and in the mold. Correctly modeling the physics of volume change on solidification, shrinkage on cooling, and contact resistance across the part-mold interface directly affects the cooling rate and ultimately the final cast shape and stress state of the cast part. In this paper we describe our current research efforts on modeling fluid fill using the commercial code ProCAST by UES, and thermal-mechanical solidification modeling using the code CAST2D by LLNL.

  14. Heat Transfer Model of Directional Solidification by LMC Process for Superalloy Casting Based on Finite Element Method

    NASA Astrophysics Data System (ADS)

    Cao, Liu; Liao, Dunming; Lu, Yuzhang; Chen, Tao

    2016-09-01

    With the rapid development of the aviation industry, the turbine blade, a critical component of the aeronautical engine, has come to be widely produced by liquid-metal cooling (LMC) process. A temperature- and time-dependent heat transfer coefficient was used to represent the heat convection between the shell and the cooling liquid, and an improved Monte Carlo ray-tracing approach was adopted to handle the boundary of radiation heat transfer. Unstructured mesh was used to fit the irregular shell boundary, and the heat transfer model of directional solidification by LMC process based on finite element method (FEM) was established. The concept of local matrix was here proposed to guarantee computational efficiency. The pouring experiments of directional solidification by LMC process were carried out, then simulation and experimental results were compared here. The accuracy of the heat transfer model was validated by the cooling curves and grain morphology, and the maximum relative error between simulation and experimental cooling curve was 2 pct. The withdrawal rate showed an important influence on the shape of solidification interface, and stray grain is liable to be generated on the bottom of platform at an excessive withdrawal rate.

  15. Chilling stress response of post-emergent cotton seedlings

    Technology Transfer Automated Retrieval System (TEKTRAN)

    • Early season development of cotton is often impaired by sudden episodes of chilling temperature. We determined the chilling response specific to post-emergent 13-d-old cotton seedlings. • Seedlings were gradually chilled during the dark period and rewarmed during the night-to-day transition. Fo...

  16. Dewaxing process using agitated heat exchanger to chill solvent-oil and wax slurry to wax filtration temperature

    SciTech Connect

    Broadhurst, Th.E.

    1984-04-10

    In an improved process for dewaxing waxy hydrocarbon oils, wherein said waxy oil is cooled in an indirect chilling zone to a temperature greater than the wax separation temperature whereby wax is precipitated to form a wax-oil-solvent slurry, cooling the slurry to the wax separation temperature in an indirect chilling zone thereby precipitating a further portion of wax from said waxy oil and separating said precipitated wax from the wax-oil-solvent slurry in solid-liquid separation means, the improvement comprises using as the indirect chilling zone an indirect heat exchanger means operated at a high level of agitation. Expressed in terms of Impeller Reynolds Number the agitation is on the order of about 1,000 to 1,000,000. Alternatively, the direct chilling zone is totally replaced by the high agitation indirect heat exchanger means.

  17. Cold Vacuum Drying (CVD) Facility Vacuum Purge System Chilled Water System Design Description (SYS 47-4)

    SciTech Connect

    IRWIN, J.J.

    2000-06-13

    This system design description (SDD) addresses the Vacuum Purge System Chilled Water (VPSCHW) system. The discussion that follows is limited to the VPSCHW system and its interfaces with associated systems. The reader's attention is directed to Drawings H-1-82162, Cold Vacuum Drying Facility Process Equipment Skid P&ID Vacuum System, and H-1-82224, Cold Vacuum Drying Facility Mechanical Utilities Process Chilled Water P&ID. Figure 1-1 shows the location and equipment arrangement for the VPSCHW system. The VPSCHW system provides chilled water to the Vacuum Purge System (VPS). The chilled water provides the ability to condense water from the multi-canister overpack (MCO) outlet gases during the MCO vacuum and purge cycles. By condensing water from the MCO purge gas, the VPS can assist in drying the contents of the MCO.

  18. Casting methods

    DOEpatents

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

    2012-12-18

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

  19. CASTING APPARATUS

    DOEpatents

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

    1958-09-23

    An apparatus is described for casting small quantities of uranlum. It consists of a crucible having a hole in the bottom with a mold positioned below. A vertical rcd passes through the hole in the crucible and has at its upper end a piercing head adapted to break the oxide skin encasing a molten uranium body. An air tight cylinder surrounds the crucible and mold, and is arranged to be evacuated.

  20. Land-based turbine casting initiative

    SciTech Connect

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

    1995-12-31

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

  1. Experimental Investigation of the Flow in a Continuous-Casting Mold under the Influence of a Transverse, Direct Current Magnetic Field

    NASA Astrophysics Data System (ADS)

    Timmel, Klaus; Eckert, Sven; Gerbeth, Gunter

    2011-02-01

    This article describes laboratory experiments aimed at investigations of flow structures and related transport processes in the continuous-casting mold under the influence of an external direct current (DC) magnetic field. The main value of cold metal laboratory experiments consists in the capabilities to obtain quantitative flow measurements with a reasonable spatial and temporal resolution. The experimental results presented here were obtained using a physical model operating with the room-temperature alloy GaInSn. According to the concept of the electromagnetic brake, the impact of a DC magnetic field on the outlet flow from the submerged entry nozzle (SEN) has been studied up to Hartmann numbers of approximately 400. The effect of the magnetic field on the flow structure turned out to be complex. The flow measurements do not manifest a general braking effect, which would be expected as an overall damping of the flow velocity and the related fluctuations all over the mold volume. Variations of the wall conductivity showed a striking impact on the resulting flow structures. The experiments provide a substantial database for the validation of respective numerical simulations.

  2. Direct Dating and Physico-Chemical Analyses Cast Doubts on the Coexistence of Humans and Dwarf Hippos in Cyprus

    PubMed Central

    Zazzo, Antoine; Lebon, Matthieu; Quiles, Anita; Reiche, Ina; Vigne, Jean-Denis

    2015-01-01

    In the Mediterranean, the island dwarf megafaunas became extinct around the end of the Pleistocene, during a period of rapid and global climate change. In Cyprus, this coincided with the first human presence on the island, as attested by the rock shelter of Akrotiri-Aetokremnos where an Epipaleolithic anthropogenic layer (stratum 2) was found overlying a massive accumulation of pygmy hippopotamus (Phanourios minor (Desmarest, 1822)) [Boekschoten and Sondaar, 1972] bones (stratum 4). The relationship between the two layers is highly controversial and the role played by humans in hippo extinction remains fiercely debated. Here, we provide new, direct radiocarbon and physico-chemical analyses on calcined bones which elucidates the complex depositional history of the assemblage. Bone turquoise was identified using micro-PIXE analysis and depth-profiling together with Vis spectroscopy, demonstrating that these bones were not freshly burned. Bayesian modeling of the radiocarbon dates indicates that stratum 4 accumulated during the first half of the 13th mill cal BP and that calcination occurred several hundred years later. We conclude that accumulation occurred naturally during the beginning of the Younger Dryas and that Epipalaeolithic visitors subsequently used the bones as fuel, starting from the mid-13th mill cal BP. At that time, dwarf hippos were probably already extinct or at least highly endangered. Our results shed new light on the possible causes of hippo extinction, on the subsequent introduction of the wild boar and on the earliest occupation of the island by humans. PMID:26284623

  3. Direct Dating and Physico-Chemical Analyses Cast Doubts on the Coexistence of Humans and Dwarf Hippos in Cyprus.

    PubMed

    Zazzo, Antoine; Lebon, Matthieu; Quiles, Anita; Reiche, Ina; Vigne, Jean-Denis

    2015-01-01

    In the Mediterranean, the island dwarf megafaunas became extinct around the end of the Pleistocene, during a period of rapid and global climate change. In Cyprus, this coincided with the first human presence on the island, as attested by the rock shelter of Akrotiri-Aetokremnos where an Epipaleolithic anthropogenic layer (stratum 2) was found overlying a massive accumulation of pygmy hippopotamus (Phanourios minor (Desmarest, 1822)) [Boekschoten and Sondaar, 1972] bones (stratum 4). The relationship between the two layers is highly controversial and the role played by humans in hippo extinction remains fiercely debated. Here, we provide new, direct radiocarbon and physico-chemical analyses on calcined bones which elucidates the complex depositional history of the assemblage. Bone turquoise was identified using micro-PIXE analysis and depth-profiling together with Vis spectroscopy, demonstrating that these bones were not freshly burned. Bayesian modeling of the radiocarbon dates indicates that stratum 4 accumulated during the first half of the 13th mill cal BP and that calcination occurred several hundred years later. We conclude that accumulation occurred naturally during the beginning of the Younger Dryas and that Epipalaeolithic visitors subsequently used the bones as fuel, starting from the mid-13th mill cal BP. At that time, dwarf hippos were probably already extinct or at least highly endangered. Our results shed new light on the possible causes of hippo extinction, on the subsequent introduction of the wild boar and on the earliest occupation of the island by humans. PMID:26284623

  4. Direct Dating and Physico-Chemical Analyses Cast Doubts on the Coexistence of Humans and Dwarf Hippos in Cyprus.

    PubMed

    Zazzo, Antoine; Lebon, Matthieu; Quiles, Anita; Reiche, Ina; Vigne, Jean-Denis

    2015-01-01

    In the Mediterranean, the island dwarf megafaunas became extinct around the end of the Pleistocene, during a period of rapid and global climate change. In Cyprus, this coincided with the first human presence on the island, as attested by the rock shelter of Akrotiri-Aetokremnos where an Epipaleolithic anthropogenic layer (stratum 2) was found overlying a massive accumulation of pygmy hippopotamus (Phanourios minor (Desmarest, 1822)) [Boekschoten and Sondaar, 1972] bones (stratum 4). The relationship between the two layers is highly controversial and the role played by humans in hippo extinction remains fiercely debated. Here, we provide new, direct radiocarbon and physico-chemical analyses on calcined bones which elucidates the complex depositional history of the assemblage. Bone turquoise was identified using micro-PIXE analysis and depth-profiling together with Vis spectroscopy, demonstrating that these bones were not freshly burned. Bayesian modeling of the radiocarbon dates indicates that stratum 4 accumulated during the first half of the 13th mill cal BP and that calcination occurred several hundred years later. We conclude that accumulation occurred naturally during the beginning of the Younger Dryas and that Epipalaeolithic visitors subsequently used the bones as fuel, starting from the mid-13th mill cal BP. At that time, dwarf hippos were probably already extinct or at least highly endangered. Our results shed new light on the possible causes of hippo extinction, on the subsequent introduction of the wild boar and on the earliest occupation of the island by humans.

  5. Guns on Campus: A Chilling Effect

    ERIC Educational Resources Information Center

    Mash, Kenneth M.

    2013-01-01

    The author of this article observes that, while much has been written on the overall topic of safety with regard to allowing guns on college campuses, little has been said about how allowing the possession of deadly weapons can create a "chilling effect" on academic discussions. This article considers how some universities have…

  6. Argon purge gas cooled by chill box

    NASA Technical Reports Server (NTRS)

    Spiro, L. W.

    1966-01-01

    Cooling argon purge gas by routing it through a shop-fabricated chill box reduces charring of tungsten inert gas torch head components. The argon gas is in a cooled state as it enters the torch and prevents buildup of char caused by the high concentrations of heat in the weld area during welding operations.

  7. Process development of thin strip steel casting

    SciTech Connect

    Sussman, R.C.; Williams, R.S.

    1990-12-01

    An important new frontier is being opened in steel processing with the emergence of thin strip casting. Casting steel directly to thin strip has enormous benefits in energy savings by potentially eliminating the need for hot reduction in a hot strip mill. This has been the driving force for numerous current research efforts into the direct strip casting of steel. The US Department of Energy initiated a program to evaluate the development of thin strip casting in the steel industry. In earlier phases of this program, planar flow casting on an experimental caster was studied by a team of engineers from Westinghouse Electric corporation and Armco Inc. A subsequent research program was designed as a fundamental and developmental study of both planar and melt overflow casting processes. This study was arranged as several separate and distinct tasks which were often completed by different teams of researchers. An early task was to design and build a water model to study fluid flow through different designs of planar flow casting nozzles. Another important task was mathematically modeling of melt overflow casting process. A mathematical solidification model for the formation of the strip in the melt overflow process was written. A study of the material and conditioning of casting substrates was made on the small wheel caster using the melt overflow casting process. This report discusses work on the development of thin steel casting.

  8. Quality assessment of rainbow trout (Oncorhynchus mykiss) fillets during super chilling and chilled storage.

    PubMed

    Shen, Song; Jiang, Yan; Liu, Xiaochang; Luo, Yongkang; Gao, Liang

    2015-08-01

    In order to evaluate the effect of super chilling (-3 °C) and chilled (3 °C) storage on the quality of rainbow trout fillets, total volatile base nitrogen (TVB-N), drip loss, pH, electric conductivity (EC), total aerobic count (TAC), K and related values, adenosine triphosphate (ATP) and related compounds, color and sensory score were determined and correlation between these indicators were analyzed. According to the comprehensive evaluation of TAC, K value and sensory score, the limit for acceptability of rainbow trout fillets was 5 days at 3 °C and 11 days at -3 °C. Additionally, the correlation coefficients between TVB-N and other freshness indicators (TAC, K value, sensory score) were relatively low. TVB-N may be inadequate for evaluating freshness changes of rainbow trout fillets compared with other indicators. Among the K and related values, H value was a better freshness indicator in rainbow trout fillets during chilled and super chilling storage for its better correlation coefficients with other freshness indicators. Super chilling storage could extend the shelf life of rainbow trout fillets by 6 days compared to chilled storage.

  9. The use of water cooling during the continuous casting of steel and aluminum alloys

    NASA Astrophysics Data System (ADS)

    Sengupta, J.; Thomas, B. G.; Wells, M. A.

    2005-01-01

    In both continuous casting of steel slabs and direct chill (DC) casting of aluminum alloy ingots, water is used to cool the mold in the initial stages of solidification, and then below the mold, where it is in direct contact with the newly solidified surface of the metal. Water cooling affects the product quality by (1) controlling the heat removal rate that creates and cools the solid shell and (2) generating thermal stresses and strains inside the solidified metal. This work reviews the current state-of-the-art in water cooling for both processes, and draws insights by comparing and contrasting the different practices used in each process. The heat extraction coefficient during secondary cooling depends greatly on the surface temperature of the ingot, as represented by boiling water-cooling curves. Thus, the heat extraction rate varies dramatically with time, as the slab/ingot surface temperature changes. Sudden fluctuations in the temperature gradients within the solidifying metal cause thermal stresses, which often lead to cracks, especially near the solidification front, where even small tensile stresses can form hot tears. Hence, a tight control of spray cooling for steel, and practices such as CO2 injection/pulse water cooling for aluminum, are now used to avoid sudden changes in the strand surface temperature. The goal in each process is to match the rate of heat removal at the surface with the internal supply of latent and sensible heat, in order to lower the metal surface temperature monotonically, until cooling is complete.

  10. Influence of transport mechanisms on nucleation and grain structure formation in DC cast aluminium alloy ingots

    NASA Astrophysics Data System (ADS)

    Bedel, M.; Založnik, M.; Kumar, A.; Combeau, H.; Jarry, P.; Waz, E.

    2012-01-01

    The grain structure formation in direct chill (DC) casting is directly linked to nucleation, which is generally promoted by inoculation. Inoculation prevents defects, but also modifies the physical properties by changing the microstructure. We studied the coupling of the nucleation on inoculant particles and the grain growth in the presence of melt flow induced by thermosolutal convection and of the transport of free-floating equiaxed grains. We used a volume-averaged two-phase multiscale model with a fully coupled description of phenomena on the grain scale (nucleation on grain refiner particles and grain growth) and on the product scale (macroscopic transport). The transport of inoculant particles is also modeled, which accounts for the inhomogeneous distribution of inoculant particles in the melt. The model was applied to an industrial sized (350mm thick) DC cast aluminium alloy ingot. A discretised nuclei size distribution was defined and the impact of different macroscopic phenomena on the grain structure formation was studied: the zone and intensity of nucleation and the resulting grain size distribution. It is shown that nucleation in the presence of macroscopic transport cannot be explained only in terms of cooling rate, but variations of composition, nuclei density and grain density, all affected by transport, must be accounted for.

  11. Casting materials

    DOEpatents

    Chaudhry, Anil R.; Dzugan, Robert; Harrington, Richard M.; Neece, Faurice D.; Singh, Nipendra P.

    2011-06-14

    A foam material comprises a liquid polymer and a liquid isocyanate which is mixed to make a solution that is poured, injected or otherwise deposited into a corresponding mold. A reaction from the mixture of the liquid polymer and liquid isocyanate inside the mold forms a thermally collapsible foam structure having a shape that corresponds to the inside surface configuration of the mold and a skin that is continuous and unbroken. Once the reaction is complete, the foam pattern is removed from the mold and may be used as a pattern in any number of conventional casting processes.

  12. Exogenous Melatonin Treatment Increases Chilling Tolerance and Induces Defense Response in Harvested Peach Fruit during Cold Storage.

    PubMed

    Cao, Shifeng; Song, Chunbo; Shao, Jiarong; Bian, Kun; Chen, Wei; Yang, Zhenfeng

    2016-06-29

    The effect of exogenous melatonin on chilling injury in peach fruit after harvest was investigated. To explore the optimum concentration of melatonin for chilling tolerance induction, peach fruit were treated with 50, 100, or 200 μM melatonin for 120 min and then stored for 28 days at 4 °C. The results showed that application of melatonin at 100 μM was most effective in reducing chilling injury of peach fruit after harvest. Peaches treated with melatonin at this concentration displayed higher levels of extractable juice rate and total soluble solids than the non-treated peaches. In addition, melatonin treatment enhanced expression of PpADC, PpODC, and PpGAD and consequently increased polyamines and γ-aminobutyric acid (GABA) contents. Meanwhile, the upregulated transcripts of PpADC and PpODC and inhibited PpPDH expression resulted in the higher proline content in melatonin-treated fruit compared to the control fruit. Our results revealed that melatonin treatment may be a useful technique to alleviate chilling injury in cold-stored peach fruit. The chilling tolerance of harvested peaches induced by melatonin treatment is associated with higher levels of polyamine, GABA, and proline. These data provided here are the first protective evidence of exogenous melatonin in harvested horticultural products in response to direct chilling stress. PMID:27281292

  13. Action of Cryogenic chill on Mechanical properties of Nickel alloy Metal Matrix Composites

    NASA Astrophysics Data System (ADS)

    Kumar, B. K. Anil; Ananthaprasad, M. G.; GopalaKrishna, K.

    2016-09-01

    In the area of material science engineering, metallurgists may be at the forefront of new technologies, developing metals for new applications, or involved in the traditional manufacture. By doing so it is possible for metallurgist to apply their knowledge of metals to solve complex problems and looking for ways to improve the mechanical properties of the materials. Therefore, an investigation in the present research was made to fabricate and evaluate the microstructure and mechanical properties of composites developed using cryogenically cooled copper chills, consisting of nickel alloy matrix and garnet particles as the reinforcement. The reinforcement being added ranges from 3 to 12 wt.% in steps of 3%. A stir casting process was used to fabricate the nickel base matrix alloy fused with garnet reinforcement particle. The matrix alloy was melted in a casting furnace at around 1350°C, the garnet particulates which was preheated to 600°C, was introduced evenly into the molten metal alloy. An arrangement was made at one end of the mould by placing copper chill blocks of varying thickness brazed with MS hallow block in which liquid nitrogen was circulated for cryogenic effect. After solidification, the composite materials thus synthesized were examined for microstructural and mechanical properties as per ASTM standards.

  14. As-Cast Residual Stresses in an Aluminum Alloy AA6063 Billet: Neutron Diffraction Measurements and Finite Element Modeling

    NASA Astrophysics Data System (ADS)

    Drezet, J.-M.; Phillion, A. B.

    2010-12-01

    The presence of thermally induced residual stresses, created during the industrial direct chill (DC) casting process of aluminum alloys, can cause both significant safety concerns and the formation of defects during downstream processing. Although numerical models have been previously developed to compute these residual stresses, most of the computations have been validated only against measured surface distortions. Recently, the variation in residual elastic strains in the steady-state regime of casting has been measured as a function of radial position using neutron diffraction (ND) in an AA6063 grain-refined cylindrical billet. In the present study, these measurements are used to show that a well-designed thermomechanical finite element (FE) process model can reproduce relatively well the experimental results. A sensitivity analysis is then carried out to determine the relative effect of the various mechanical parameters when computing the as-cast residual stresses in a cylindrical billet. Two model parameters have been investigated: the temperature when the alloy starts to thermally contract and the plasticity behavior. It is shown that the mechanical properties at low temperatures have a much larger influence on the residual stresses than those at high temperatures.

  15. Evolution of Fe Bearing Intermetallics During DC Casting and Homogenization of an Al-Mg-Si Al Alloy

    NASA Astrophysics Data System (ADS)

    Kumar, S.; Grant, P. S.; O'Reilly, K. A. Q.

    2016-06-01

    The evolution of iron (Fe) bearing intermetallics (Fe-IMCs) during direct chill casting and homogenization of a grain-refined 6063 aluminum-magnesium-silicon (Al-Mg-Si) alloy has been studied. The as-cast and homogenized microstructure contained Fe-IMCs at the grain boundaries and within Al grains. The primary α-Al grain size, α-Al dendritic arm spacing, IMC particle size, and IMC three-dimensional (3D) inter-connectivity increased from the edge to the center of the as-cast billet; both α c-AlFeSi and β-AlFeSi Fe-IMCs were identified, and overall α c-AlFeSi was predominant. For the first time in industrial billets, the different Fe-rich IMCs have been characterized into types based on their 3D chemistry and morphology. Additionally, the role of β-AlFeSi in nucleating Mg2Si particles has been identified. After homogenization, α c-AlFeSi predominated across the entire billet cross section, with marked changes in the 3D morphology and strong reductions in inter-connectivity, both supporting a recovery in alloy ductility.

  16. Flow Analysis on a Limited Volume Chilled Water System

    SciTech Connect

    Zheng, Lin

    2012-07-31

    LANL Currently has a limited volume chilled water system for use in a glove box, but the system needs to be updated. Before we start building our new system, a flow analysis is needed to ensure that there are no high flow rates, extreme pressures, or any other hazards involved in the system. In this project the piping system is extremely important to us because it directly affects the overall design of the entire system. The primary components necessary for the chilled water piping system are shown in the design. They include the pipes themselves (perhaps of more than one diameter), the various fitting used to connect the individual pipes to form the desired system, the flow rate control devices (valves), and the pumps that add energy to the fluid. Even the most simple pipe systems are actually quite complex when they are viewed in terms of rigorous analytical considerations. I used an 'exact' analysis and dimensional analysis considerations combined with experimental results for this project. When 'real-world' effects are important (such as viscous effects in pipe flows), it is often difficult or impossible to use only theoretical methods to obtain the desired results. A judicious combination of experimental data with theoretical considerations and dimensional analysis are needed in order to reduce risks to an acceptable level.

  17. Center crack detection during continuous casting of aluminum by laser ultrasonic measurements

    NASA Astrophysics Data System (ADS)

    Grün, Hubert; Mitter, Thomas; Roither, Jürgen; Betz, Andreas; Bozorgi, Salar; Burgholzer, Peter

    2014-05-01

    Crack detection during continuous direct chill casting of aluminum is a matter of economics. Determining cracks during production process saves money, energy and raw material. Of course, a non-destructive method is required for this evaluation. Because of temperature concerns conventional ultrasound is not applicable. One non-contact alternative is laser ultrasonics. In laser ultrasonics short laser pulses illuminate the sample. The electromagnetic energy gets absorbed at the surface of the sample and results in local heating followed by expansion. Thereby broadband ultrasonic waves are launched which propagate through the sample and get back reflected or scattered at interfaces (cracks, blowholes,…) like conventional ultrasonic waves. Therefore laser ultrasonics is an alternative thermal infrared technology. By using an interferometer also the detection of the ultrasonic waves at the sample surface is done in a remote manner. During preliminary examinations in the lab by scanning different aluminum studs it was able to distinguish between studs with and without cracks. The prediction of the dimension of the crack by evaluation of the damping of the broadband ultrasonic waves was possible. With simple image reconstruction methods one can localize the crack and give an estimation of its extent and even its shape. Subsequent first measurements using this laser ultrasonic setup during the continuous casting of aluminum were carried out and showed the proof of principle in an industrial environment with elevated temperatures, dust, cooling water and vibrations.

  18. A silicon sheet casting experiment. [for solar cell water production

    NASA Technical Reports Server (NTRS)

    Bickler, D. B.; Sanchez, L. E.; Sampson, W. J.

    1980-01-01

    The casting of silicon blanks for solar cells directly without slicing is an exciting concept. An experiment was performed to investigate the feasibility of developing a machine that casts wafers directly. A Czochralski furnace was modified to accept a graphite ingot-simulating fixture. Silicon was melted in the middle of the ingot simulator in a boron nitride mold. Sample castings showed reasonable crystal size. Solar cells were made from the cast blanks. The performance is reported.

  19. EPA's ToxCast Project: Lessons learned and future directions for use of HTS in predicting in vivo toxicology -- A Chemical Perspective

    EPA Science Inventory

    U.S. EPA’s ToxCast and the related Tox21 projects are employing high-throughput screening (HTS) technologies to profile thousands of chemicals, which in turn serve as probes of a wide diversity of targets, pathways and mechanisms related to toxicity. Initial models relating ToxCa...

  20. Chilling Injury Induces Lipid Phase Changes in Membranes of Tomato Fruit.

    PubMed Central

    Sharom, M.; Willemot, C.; Thompson, J. E.

    1994-01-01

    Wide-angle x-ray diffraction has provided evidence for lipid phase separations in microsomal membranes from chill-injured tomato (Lycopersicon esculentum Mill. cv Caruso) fruit. Mature-green fruit stored for 20 d at 5[deg]C had not begun to ripen and were essentially free of chilling injury symptoms. Within 4 d of being returned to 25[deg]C, however, the fruit displayed characteristic symptoms of chilling injury, including translucent water-soaked patches, surface pitting, and irregular pigmentation. Membrane damage measured as electrolyte leakage from pericarp discs intensified after the fruit were returned to ambient temperature. Wide-angle x-ray diffraction patterns recorded at 25[deg]C for microsomal membranes isolated from untreated, mature-green fruit indicated that the membrane bilayers were exclusively liquid-crystalline. Diffraction patterns for microsomal membranes from fruit stored for 20 d at 5[deg]C showed only trace amounts of gel phase lipid, but within 4 d of subsequent exposure of the fruit to ambient temperature, there was evidence for a pronounced lateral phase separation of lipids within the membranes that would render them leaky. Inas-much as the phase separations were detectable at 25[deg]C and became pronounced only subsequent to the chilling episode, they appear to be an indirect rather than direct effect of exposure to low temperature. The diffraction data thus support the notion that the lipid phase changes observed here are not directly induced by low temperature but rather reflect subsequent biochemical changes in the bilayers that may contribute to the development of chilling symptoms. PMID:12232203

  1. Thin Wall Iron Castings

    SciTech Connect

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

    2001-10-31

    Results of an investigation made to develop methods of making iron castings having wall thicknesses as small as 2.5 mm in green sand molds are presented. It was found that thin wall ductile and compacted graphite iron castings can be made and have properties consistent with heavier castings. Green sand molding variables that affect casting dimensions were also identified.

  2. Dewaxing waxy oil by dilution chilling employing static mixing means

    SciTech Connect

    Shaw, D. H.; Hall, R. R.

    1985-04-30

    An improved process for the solvent dewaxing of petroleum oil stocks. Wax-containing oil is chilled in an elongated chilling zone by introducing cold dewaxing solvent into said zone, at a plurality of points along same, said chilling zone containing or having associated with it a plurality of static means for mixing the solvent and wax-containing oil under conditions of plug flow radial mixing, thereby avoiding shock chilling without the need for the intense agitation and/or dynamic agitators normally required for such processes.

  3. Effect of impression material on surface reactive layer when casting pure titanium in phosphate investment.

    PubMed

    Komasa, Y; Moriguchi, A; Asai, M; Nezumi, M; Kakimoto, K; Gonda, Y

    1998-10-01

    We evaluated the effect of impression materials used in preparation of pure titanium castings on the surface reactive layer. Surface roughness of the refractory models before and after firing was smaller when silicone rather than agar impression material was used. The surface roughness of castings prepared with T-invest varied little with the impression material. However, the surface roughness of the castings prepared with CD Titaninvest was less when silicone impression material was used. Surface hardness of the castings was slightly greater when agar impression material was used, and metallic texture analysis of the surface of the castings showed a chill layer and a columnar crystal layer extending from the surface toward the interior. A relatively non-corroded white layer and a markedly corroded black layer were observed in the chill layer, and their thickness was smaller when silicone impression material was used. Use of the Electron Probe Micro Analyzer (EPMA) to determine distribution of various elements in the superficial layer of the casting plates showed that the reactive layer contained less P and Si when silicone impression material was used rather than agar. NH4H2 PO4, which is a component of the bonding material in the investment, was present at a high concentration in the superficial layer of the agar impression material. This shows the importance of preparing refractory models with a non-water-absorbing impression material to obtain pure titanium casting plates with a smaller reactive layer.

  4. Gating of Permanent Molds for ALuminum Casting

    SciTech Connect

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

    2004-03-30

    This report summarizes a two-year project, DE-FC07-01ID13983 that concerns the gating of aluminum castings in permanent molds. The main goal of the project is to improve the quality of aluminum castings produced in permanent molds. The approach taken was determine how the vertical type gating systems used for permanent mold castings can be designed to fill the mold cavity with a minimum of damage to the quality of the resulting casting. It is evident that somewhat different systems are preferred for different shapes and sizes of aluminum castings. The main problems caused by improper gating are entrained aluminum oxide films and entrapped gas. The project highlights the characteristic features of gating systems used in permanent mold aluminum foundries and recommends gating procedures designed to avoid common defects. The study also provides direct evidence on the filling pattern and heat flow behavior in permanent mold castings.

  5. Casting system effectiveness--measurement and theory.

    PubMed

    Luk, H W; Darvell, B W

    1992-03-01

    Evaluating castability as a property of dental casting alloys is an unworkable concept, since any measure is demonstrably affected by several external factors. Casting System Effectiveness (CSE) is shown experimentally and theoretically to depend primarily upon the time taken for the advancing front to freeze. A spiral tube mold was used to measure casting length obtained under variations in casting temperature; this pattern is proposed as a standard measure of CSE. A Bernoulli 'free-fall' numerical model is shown to reproduce the principal features of such casting, with some evidence of viscosity limitation of the turbulent flow at long casting lengths. Direct measurement of melt velocities confirmed turbulent flow in the mold. A method is also suggested for assessing the influence of investment porosity on CSE.

  6. Ultraviolet-B Radiation (UV-B) Relieves Chilling-Light-Induced PSI Photoinhibition And Accelerates The Recovery Of CO2 Assimilation In Cucumber (Cucumis sativus L.) Leaves

    PubMed Central

    Zhang, Zi-Shan; Jin, Li-Qiao; Li, Yu-Ting; Tikkanen, Mikko; Li, Qing-Ming; Ai, Xi-Zhen; Gao, Hui-Yuan

    2016-01-01

    Ultraviolet-B radiation (UV-B) is generally considered to negatively impact the photosynthetic apparatus and plant growth. UV-B damages PSII but does not directly influence PSI. However, PSI and PSII successively drive photosynthetic electron transfer, therefore, the interaction between these systems is unavoidable. So we speculated that UV-B could indirectly affect PSI under chilling-light conditions. To test this hypothesis, the cucumber leaves were illuminated by UV-B prior or during the chilling-light treatment, and the leaves were then transferred to 25 °C and low-light conditions for recovery. The results showed that UV-B decreased the electron transfer to PSI by inactivating the oxygen-evolving complex (OEC), thereby protecting PSI from chilling-light-induced photoinhibition. This effect advantages the recoveries of PSI and CO2 assimilation after chilling-light stress, therefore should minimize the yield loss caused by chilling-light stress. Because sunlight consists of both UV-B and visible light, we suggest that UV-B-induced OEC inactivation is critical for chilling-light-induced PSI photoinhibition in field. Moreover, additional UV-B irradiation is an effective strategy to relieve PSI photoinhibition and yield loss in protected cultivation during winter. This study also demonstrates that minimizing the photoinhibition of PSI rather than that of PSII is essential for the chilling-light tolerance of the plant photosynthetic apparatus. PMID:27686324

  7. Casting Shadows in the Science Classroom.

    ERIC Educational Resources Information Center

    Nolan, Kathleen

    2003-01-01

    Uses the metaphor of shadows in a critical exploration of what it means to know and how the cultures of classrooms have shaped these images of knowing. Directs attention to objects that cast shadows on the learning and knowing of mathematics and science through the voices of preservice teachers. Discusses shadow casting toward textbooks, teachers,…

  8. Tomato flavor changes at chilling and non-chilling temperatures as influenced by controlled atmospheres

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Postharvest temperatures recommended as safe to avoid chilling injury (CI) based on lack of visible symptoms suppress tomato aroma development. We investigated how temperatures at or above the putative CI threshold of 12.5°C affected aroma of pink ‘Tasti Lee’ tomatoes and if controlled atmosphere (C...

  9. Performance of a chill ATES system

    SciTech Connect

    Midkiff, K.C.; Song, Y.K.; Schaetzle, W.J.

    1989-03-01

    An aquifer air-conditioning system has been installed to cool the Student Recreation Center on the University of Alabama Campus. This research program encompasses the monitoring of the operation of the aquifer system and provision of emplacements to the system. The monitoring includes establishing the instrumentation, acquiring data, and analyzing the results. The instrumentation allows the measurement of water flow rates and corresponding temperatures, electrical energy input, aquifer temperatures at nineteen monitoring wells, and aquifer levels at six monitoring wells. Recent acquifer performance data indicate that 76% of the chill energy stored was recovered for the period Oct/86 - Sep/87 and 70% for the period Oct/87 - Sep/88. This is a substantial improvement over recoveries of 38% for the 1985 season and 55% for 1986. The overall coefficient of performance was 5.4 for Oct/86 - Sep/87 and 4.6 for Oct/87 - Sep/88. THe system has supplied 100% of the cooling with only about one-half of the energy input required by a conventional system. Some of the increased recovery of chilled water is a result of modifying the production well operation to reduce the regional flow of water toward the northwest. All warm water is withdrawn form the southeast wells, chilled, and injected in northwest wells. The cold water then withdrawn from the cold wells is used for air-conditioning but not reinjected into the aquifer. Additional flow control is provided by pumping (and discarding) water out of a southeast well, although the complete results of this new strategy are as yet unclear.

  10. Wind chill factor applied to Patagonian climatology

    NASA Astrophysics Data System (ADS)

    Coronato, Fernando R.

    1993-03-01

    The wind cooling effect determines wind chill equivalent-temperatures, which may be rather different to actual temperature. In a windy region such as Patagonia, this difference may reach a magnitude and persistence to become an important bioclimatic element. This paper quantifies the wind cooling effect in Patagonia by the presentation of equivalent isotherms as an adaptation of the usual isotherm maps to the regional bioclimatic environment. It is concluded that due to seasonal variations in wind speed, the annual equivalent temperature range is smaller than the actual temperature range, thus increasing oceanic features, from a thermal viewpoint, of the Patagonian climate.

  11. Grinding of cast iron with wheels made of superhard materials

    NASA Astrophysics Data System (ADS)

    Korz, N. J.

    Optimum grinding conditions for cast iron with wheels made of superhard materials were determined. Type PP 250 x 10 wheels made of metallized and non metallized diamond and various brands of CBN with 125/100 grains at 100 % concentration on metellic M0 16 and organic B1 type bonds were used. Type KZ 25 CMIK 5 wheels of the same size were investigated for purposes of comparison. The experimental samples, 80 and 230 mm in diameter made from grey cast iron (HB 178), alloy cast iron (HB 200), high strength cast iron (HB 207), chilled cast iron (HB 460) and hardened cast iron (HCR 52-55), were ground on a 3 B 12 cylindrical grinder at cutting speeds of 35 m/sec, a workpiece velocity of 54 m/min and a longitudinal feed of 0,5 - 2,0 m/min. The crossfeed ranges rom 0,005 to 0,4 mm/sec. The cutting fluid was an aqueous solution of calcium carbonate supplied at 3 to 5 l/min.

  12. Chilling and heat requirements for flowering in temperate fruit trees

    NASA Astrophysics Data System (ADS)

    Guo, Liang; Dai, Junhu; Ranjitkar, Sailesh; Yu, Haiying; Xu, Jianchu; Luedeling, Eike

    2014-08-01

    Climate change has affected the rates of chilling and heat accumulation, which are vital for flowering and production, in temperate fruit trees, but few studies have been conducted in the cold-winter climates of East Asia. To evaluate tree responses to variation in chill and heat accumulation rates, partial least squares regression was used to correlate first flowering dates of chestnut ( Castanea mollissima Blume) and jujube ( Zizyphus jujube Mill.) in Beijing, China, with daily chill and heat accumulation between 1963 and 2008. The Dynamic Model and the Growing Degree Hour Model were used to convert daily records of minimum and maximum temperature into horticulturally meaningful metrics. Regression analyses identified the chilling and forcing periods for chestnut and jujube. The forcing periods started when half the chilling requirements were fulfilled. Over the past 50 years, heat accumulation during tree dormancy increased significantly, while chill accumulation remained relatively stable for both species. Heat accumulation was the main driver of bloom timing, with effects of variation in chill accumulation negligible in Beijing's cold-winter climate. It does not seem likely that reductions in chill will have a major effect on the studied species in Beijing in the near future. Such problems are much more likely for trees grown in locations that are substantially warmer than their native habitats, such as temperate species in the subtropics and tropics.

  13. Increasing chilling reduces heat requirement for floral budbreak in peach

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Response to chilling temperatures is a critical factor in the suitability of peach [Prunus persica (L.) Batsch] cultivars to moderate climates such as in the southeastern United States. Time of bloom depends on the innate chilling requirement of the cultivar as well as the timing and quantity of co...

  14. 76 FR 166 - Fresh and Chilled Atlantic Salmon From Norway

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-03

    ... imports of fresh and chilled Atlantic salmon from Norway (56 FR 14920, 14921). Following five-year reviews... imports of fresh and chilled Atlantic salmon from Norway (71 FR 7512). The Commission is now conducting...), as most recently amended at 74 FR 2847 (January 16, 2009). \\1\\ \\1\\ No response to this request...

  15. Chilling and heat requirements for flowering in temperate fruit trees.

    PubMed

    Guo, Liang; Dai, Junhu; Ranjitkar, Sailesh; Yu, Haiying; Xu, Jianchu; Luedeling, Eike

    2014-08-01

    Climate change has affected the rates of chilling and heat accumulation, which are vital for flowering and production, in temperate fruit trees, but few studies have been conducted in the cold-winter climates of East Asia. To evaluate tree responses to variation in chill and heat accumulation rates, partial least squares regression was used to correlate first flowering dates of chestnut (Castanea mollissima Blume) and jujube (Zizyphus jujube Mill.) in Beijing, China, with daily chill and heat accumulation between 1963 and 2008. The Dynamic Model and the Growing Degree Hour Model were used to convert daily records of minimum and maximum temperature into horticulturally meaningful metrics. Regression analyses identified the chilling and forcing periods for chestnut and jujube. The forcing periods started when half the chilling requirements were fulfilled. Over the past 50 years, heat accumulation during tree dormancy increased significantly, while chill accumulation remained relatively stable for both species. Heat accumulation was the main driver of bloom timing, with effects of variation in chill accumulation negligible in Beijing’s cold-winter climate. It does not seem likely that reductions in chill will have a major effect on the studied species in Beijing in the near future. Such problems are much more likely for trees grown in locations that are substantially warmer than their native habitats, such as temperate species in the subtropics and tropics. PMID:23958788

  16. Chilling and heat requirements for flowering in temperate fruit trees.

    PubMed

    Guo, Liang; Dai, Junhu; Ranjitkar, Sailesh; Yu, Haiying; Xu, Jianchu; Luedeling, Eike

    2014-08-01

    Climate change has affected the rates of chilling and heat accumulation, which are vital for flowering and production, in temperate fruit trees, but few studies have been conducted in the cold-winter climates of East Asia. To evaluate tree responses to variation in chill and heat accumulation rates, partial least squares regression was used to correlate first flowering dates of chestnut (Castanea mollissima Blume) and jujube (Zizyphus jujube Mill.) in Beijing, China, with daily chill and heat accumulation between 1963 and 2008. The Dynamic Model and the Growing Degree Hour Model were used to convert daily records of minimum and maximum temperature into horticulturally meaningful metrics. Regression analyses identified the chilling and forcing periods for chestnut and jujube. The forcing periods started when half the chilling requirements were fulfilled. Over the past 50 years, heat accumulation during tree dormancy increased significantly, while chill accumulation remained relatively stable for both species. Heat accumulation was the main driver of bloom timing, with effects of variation in chill accumulation negligible in Beijing’s cold-winter climate. It does not seem likely that reductions in chill will have a major effect on the studied species in Beijing in the near future. Such problems are much more likely for trees grown in locations that are substantially warmer than their native habitats, such as temperate species in the subtropics and tropics.

  17. Quality and safety of broiler meat in various chilling systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chilling is a critical step in poultry processing to attain high quality meat and to meet the USDA-FSIS temperature standards. This study was conducted to determine the effects of commercially available chilling systems on quality and safety of broiler meat. A total of 300 carcasses in two replica...

  18. Processing and Characterization of Functionally Graded Aluminum (A319)—SiCp Metallic Composites by Centrifugal Casting Technique

    NASA Astrophysics Data System (ADS)

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

    2016-08-01

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

  19. The Chilled-Mirror Humidity Sensor: Improved Radiosonde Measurements

    NASA Technical Reports Server (NTRS)

    Schmidlin, F. J.

    1999-01-01

    Chilled-mirror humidity sensor technology recently was adapted for use with the VIZ radiosonde. The principle of the chilled-mirror operation is to lower its temperature until dew forms on the mirror, at that point the dew point temperature is noted and the mirror is then heated to evaporate the moisture. The cycle is repeated. Research conducted from NASA's Wallops Flight Facility has provided comparisons between the chilled-mirror sensor and the carbon hygristor of VIZ, and the capacitive sensors of AIR Inc. and Vaisala Co. We believe the chilled-mirror sensor is accurate and would serve as a reference standard for evaluating operational radiosonde relative humidity sensors. Thus, differences seen in the comparisons are beginning to furnish insight into developing better humidity sensors. We discuss these comparison results as well as reproducibility results from a dual chilled-mirror measurement.

  20. Diurnal variation of wind-chill at Thessaloniki, Greece

    NASA Astrophysics Data System (ADS)

    Balafoutis, Ch. J.

    1989-12-01

    The diurnal variations of wind-chill at Thessaloniki, Greece, are considered using hourly data from January 1960 to December 1977. This is the first attempt in Greece to describe bioclimatic conditions using wind-chill data. The hourly values of wind-chill were calculated by Siple-Passel's formula which still appears to be most widely used. The values of wind-chill are discussed in terms of Terjung's scale. Thessaloniki does not experience “frost-bite” conditions during the coldest months but does experience “warm” conditions during the summer period. A comparison of hourly and daily mean values show that the means do not indicate the real range of wind-chill during the day.

  1. Effects of chilling on protein synthesis in tomato suspension cultures

    SciTech Connect

    Matadial, B.; Pauls, K.P. )

    1989-04-01

    The effect of chilling on cell growth, cell viability, protein content and protein composition in suspension cultures of L. esculentum and L. hirsutum was investigated. Cell growth for both species was arrested at 2{degrees}C but when cultures were transferred to 25{degree}C cell growth resumed. There was no difference in viability between control and chilled cultures of L. esculentum, however, L. hirsutum control cultures exhibited larger amounts of Fluorescein Diacetate induced fluorescence than chilled cultures. {sup 35}S-methionine incorporation into proteins was 2.5-2 times higher in L. hirsutum than in L. esculentum. Quantitative and qualitative differences, in {sup 35}S-methionine labelled proteins, between chilled and control cultures were observed by SDS-PAGE and fluorography. Protein content in chilled cultures decreased over time but then increased when cultures were transferred to 25{degrees}C.

  2. Application of TRIZ Theory in Patternless Casting Manufacturing Technique

    NASA Astrophysics Data System (ADS)

    Yang, Weidong; Gan, Dequan; Jiang, Ping; Tian, Yumei

    The ultimate goal of Patternless Casting Manufacturing (referred to as PCM) is how to obtain the casts by casting the sand mold directly. In the previous PCM, the resin content of sand mold is much higher than that required by traditional resin sand, so the casts obtained are difficult to be sound and qualified products, which limits the application of this technique greatly. In this paper, the TRIZ algorithm is introduced to the innovation process in PCM systematically.

  3. Nut crop yield records show that budbreak-based chilling requirements may not reflect yield decline chill thresholds

    NASA Astrophysics Data System (ADS)

    Pope, Katherine S.; Dose, Volker; Da Silva, David; Brown, Patrick H.; DeJong, Theodore M.

    2015-06-01

    Warming winters due to climate change may critically affect temperate tree species. Insufficiently cold winters are thought to result in fewer viable flower buds and the subsequent development of fewer fruits or nuts, decreasing the yield of an orchard or fecundity of a species. The best existing approximation for a threshold of sufficient cold accumulation, the "chilling requirement" of a species or variety, has been quantified by manipulating or modeling the conditions that result in dormant bud breaking. However, the physiological processes that affect budbreak are not the same as those that determine yield. This study sought to test whether budbreak-based chilling thresholds can reasonably approximate the thresholds that affect yield, particularly regarding the potential impacts of climate change on temperate tree crop yields. County-wide yield records for almond ( Prunus dulcis), pistachio ( Pistacia vera), and walnut ( Juglans regia) in the Central Valley of California were compared with 50 years of weather records. Bayesian nonparametric function estimation was used to model yield potentials at varying amounts of chill accumulation. In almonds, average yields occurred when chill accumulation was close to the budbreak-based chilling requirement. However, in the other two crops, pistachios and walnuts, the best previous estimate of the budbreak-based chilling requirements was 19-32 % higher than the chilling accumulations associated with average or above average yields. This research indicates that physiological processes beyond requirements for budbreak should be considered when estimating chill accumulation thresholds of yield decline and potential impacts of climate change.

  4. Plastic casting resin poisoning

    MedlinePlus

    Epoxy poisoning; Resin poisoning ... Epoxy and resin can be poisonous if they are swallowed or their fumes are breathed in. ... Plastic casting resins are found in various plastic casting resin products.

  5. Cool Cast Facts

    MedlinePlus

    ... outer layer is usually made of plaster or fiberglass. Fiberglass casts are made of fiberglass, which is a plastic that can be shaped. Fiberglass casts come in many different colors — if you' ...

  6. Direct Tensile Strength and Characteristics of Dentin Restored with All-Ceramic, Resin-Composite, and Cast Metal Prostheses Cemented with Resin Adhesives

    PubMed Central

    Piemjai, Morakot; Nakabayashi, Nobuo

    2015-01-01

    A dentin-cement-prosthesis complex restored with either all-porcelain, cured resin-composite, or cast base metal alloy and cemented with either of the different resin cements was trimmed into a mini-dumbbell shape for tensile testing. The fractured surfaces and characterization of the dentin-cement interface of bonded specimens were investigated using a Scanning Electron Microscope. A significantly higher tensile strength of all-porcelain (12.5 ± 2.2 MPa) than that of cast metal (9.2 ± 3.5 MPa) restorations was revealed with cohesive failure in the cement and failure at the prosthesis-cement interface in Super-Bond C&B group. No significant difference in tensile strength was found among the types of restorations using the other three cements with adhesive failure on the dentin side and cohesive failure in the cured resin. SEM micrographs demonstrated the consistent hybridized dentin in Super-Bond C&B specimens that could resist degradation when immersed in hydrochloric acid followed by NaOCl solutions whereas a detached and degraded interfacial layer was found for the other cements. The results suggest that when complete hybridization of resin into dentin occurs tensile strength at the dentin-cement is higher than at the cement-prosthesis interfaces. The impermeable hybridized dentin can protect the underlying dentin and pulp from acid demineralization, even if detachment of the prosthesis has occurred. PMID:26539520

  7. Direct Tensile Strength and Characteristics of Dentin Restored with All-Ceramic, Resin-Composite, and Cast Metal Prostheses Cemented with Resin Adhesives.

    PubMed

    Piemjai, Morakot; Nakabayashi, Nobuo

    2015-01-01

    A dentin-cement-prosthesis complex restored with either all-porcelain, cured resin-composite, or cast base metal alloy and cemented with either of the different resin cements was trimmed into a mini-dumbbell shape for tensile testing. The fractured surfaces and characterization of the dentin-cement interface of bonded specimens were investigated using a Scanning Electron Microscope. A significantly higher tensile strength of all-porcelain (12.5 ± 2.2 MPa) than that of cast metal (9.2 ± 3.5 MPa) restorations was revealed with cohesive failure in the cement and failure at the prosthesis-cement interface in Super-Bond C&B group. No significant difference in tensile strength was found among the types of restorations using the other three cements with adhesive failure on the dentin side and cohesive failure in the cured resin. SEM micrographs demonstrated the consistent hybridized dentin in Super-Bond C&B specimens that could resist degradation when immersed in hydrochloric acid followed by NaOCl solutions whereas a detached and degraded interfacial layer was found for the other cements. The results suggest that when complete hybridization of resin into dentin occurs tensile strength at the dentin-cement is higher than at the cement-prosthesis interfaces. The impermeable hybridized dentin can protect the underlying dentin and pulp from acid demineralization, even if detachment of the prosthesis has occurred.

  8. Filler metal alloy for welding cast nickel aluminide alloys

    DOEpatents

    Santella, Michael L.; Sikka, Vinod K.

    1998-01-01

    A filler metal alloy used as a filler for welding east nickel aluminide alloys contains from about 15 to about 17 wt. % chromium, from about 4 to about 5 wt. % aluminum, equal to or less than about 1.5 wt. % molybdenum, from about 1 to about 4.5 wt. % zirconium, equal to or less than about 0.01 wt. % yttrium, equal to or less than about 0.01 wt. % boron and the balance nickel. The filler metal alloy is made by melting and casting techniques such as are melting the components of the filler metal alloy and east in copper chill molds.

  9. A New Approach to an Accurate Wind Chill Factor.

    NASA Astrophysics Data System (ADS)

    Bluestein, Maurice; Zecher, Jack

    1999-09-01

    Winter weather often shows a severity marked by low dry-bulb temperature combined with high wind speed. The wind chill factor is now a standard meteorological term to express this severity. This factor, or more appropriately the wind chill temperature, represents that air temperature without wind that would effect the same heat loss rate from bare human skin as that due to the actual combined dry-bulb temperature and wind. Currently used wind chill factors derive from a study conducted by the U.S. Antarctic Service over 50 years ago. The data then collected was used to develop a cooling rate as a function of wind speed, which in turn was used to formulate an equation still in use today. The equation is based on primitive experiments with a container of freezing water and an unrealistically high human skin temperature. A more appropriate estimate of the thermal properties of the skin and implementation of modern heat transfer theory can provide a more realistic wind chill factor. Recent research studies suggest that the wind chill equation currently used overestimates the effect of the wind for the range of temperatures and wind speeds expected. This paper provides a new formula for the wind chill factor and a chart of wind chill temperatures for various combinations of dry-bulb temperatures and wind speeds as measured by standard techniques.

  10. Mechanics of buried chilled gas pipelines

    SciTech Connect

    Selvadurai, A.P.S.; Hu, J.

    1996-12-31

    This paper examines the factors influencing the modelling of soil-pipeline interaction for a pipeline which is used to transport chilled gas. The soil-pipeline interaction is induced by the generation of discontinuous frost heave at a boundary between soils with differing frost susceptibility. The three-dimensional modelling takes into consideration the time-dependent evolution of frost heave due to moisture migration, the creep and elastic behavior of the frozen soil and flexural behavior of the embedded pipeline. The results of the computational model are compared with experimental results obtained from the frost heave induced soil-pipeline interaction test performed at the full scale test facilities in Caen, France.

  11. Comparative Transcriptome Profiling of Chilling Stress Responsiveness in Two Contrasting Rice Genotypes

    PubMed Central

    Zhang, Ting; Zhao, Xiuqin; Wang, Wensheng; Pan, Yajiao; Huang, Liyu; Liu, Xiaoyue; Zong, Ying; Zhu, Linghua; Yang, Daichang; Fu, Binying

    2012-01-01

    Rice is sensitive to chilling stress, especially at the seedling stage. To elucidate the molecular genetic mechanisms of chilling tolerance in rice, comprehensive gene expressions of two rice genotypes (chilling-tolerant LTH and chilling-sensitive IR29) with contrasting responses to chilling stress were comparatively analyzed. Results revealed a differential constitutive gene expression prior to stress and distinct global transcription reprogramming between the two rice genotypes under time-series chilling stress and subsequent recovery conditions. A set of genes with higher basal expression were identified in chilling-tolerant LTH compared with chilling-sensitive IR29, indicating their possible role in intrinsic tolerance to chilling stress. Under chilling stress, the major effect on gene expression was up-regulation in the chilling- tolerant genotype and strong repression in chilling-sensitive genotype. Early responses to chilling stress in both genotypes featured commonly up-regulated genes related to transcription regulation and signal transduction, while functional categories for late phase chilling regulated genes were diverse with a wide range of functional adaptations to continuous stress. Following the cessation of chilling treatments, there was quick and efficient reversion of gene expression in the chilling-tolerant genotype, while the chilling-sensitive genotype displayed considerably slower recovering capacity at the transcriptional level. In addition, the detection of differentially-regulated TF genes and enriched cis-elements demonstrated that multiple regulatory pathways, including CBF and MYBS3 regulons, were involved in chilling stress tolerance. A number of the chilling-regulated genes identified in this study were co-localized onto previously fine-mapped cold-tolerance-related QTLs, providing candidates for gene cloning and elucidation of molecular mechanisms responsible for chilling tolerance in rice. PMID:22912843

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

    PubMed

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

    2012-07-01

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

  13. Microstructure and Elemental Distribution in a Cast Austenitic Steel

    SciTech Connect

    Kenik, Edward A; Busby, Jeremy T; Hoelzer, David T; Rowcliffe, Arthur Frederick; Vitek, John Michael

    2007-01-01

    Casting of austenitic stainless steels offers the possibility of directly producing large and/or complex structures, such as the first wall shield module or the diverter cassette for the International Tokomak Experimental Reactor. However, the resulting mechanical properties and the corrosion resistance of such cast components can be inferior compared to conventionally forged components because of the larger grain size, lower dislocation density and extensive segregation inherent in the cast material. This study examines the microstructural and compositional heterogeneities of a large casting of 316N stainless steel, as well as the possibility of improving the homogeneity and mechanical properties of such a cast material.

  14. Chemical additive to enhance antimicrobial efficacy of chlorine and control cross-contamination during immersion chill of broiler carcasses.

    PubMed

    Schambach, B T; Berrang, M E; Harrison, M A; Meinersmann, R J

    2014-09-01

    Immersion chilling of broiler carcasses can be a site for cross-contamination between the occasional highly contaminated carcass and those that are co-chilled. Chlorine is often used as an antimicrobial but can be overcome by organic material. A proprietary chlorine stabilizer (T-128) based on phosphoric acid-propylene glycol was tested as a chill tank additive in experiments simulating commercial broiler chilling. In bench-scale experiments, 0.5% T-128 was compared with plain water (control), 50 ppm of chlorine, and the combination of 0.5% T-128 with 50 ppm of chlorine to control transfer of Salmonella and Campylobacter from inoculated wing drummettes to co-chilled uninoculated drummettes. Both chlorine and T-128 lessened cross-contamination with Salmonella (P < 0.05); T-128 and T-128 with chlorine were significantly more effective (P < 0.05) than the control or plain chlorine for control of Campylobacter. T-128 treatments were noted to have a pH of less than 4.0; an additional experiment demonstrated that the antimicrobial effect of T-128 was not due merely to a lower pH. In commercial broiler chilling, a pH close to 6.0 is preferred to maximize chlorine effectiveness, while maintaining water-holding capacity of the meat. In a set of pilot-scale experiments with T-128, a near-ideal pH of 6.3 was achieved by using tap water instead of the distilled water used in bench-scale experiments. Pilot-scale chill tanks were used to compare the combination of 0.5% T-128 and 50 ppm of chlorine with 50 ppm of plain chlorine for control of cross-contamination between whole carcasses inoculated with Salmonella and Campylobacter and co-chilled uninoculated carcasses. The T-128 treatment resulted in significantly less crosscontamination by either direct contact or water transfer with both organisms compared with plain chlorine treatment. T-128 may have use in commercial broiler processing to enhance the effectiveness of chlorine in processing water. PMID:25198851

  15. Chemical additive to enhance antimicrobial efficacy of chlorine and control cross-contamination during immersion chill of broiler carcasses.

    PubMed

    Schambach, B T; Berrang, M E; Harrison, M A; Meinersmann, R J

    2014-09-01

    Immersion chilling of broiler carcasses can be a site for cross-contamination between the occasional highly contaminated carcass and those that are co-chilled. Chlorine is often used as an antimicrobial but can be overcome by organic material. A proprietary chlorine stabilizer (T-128) based on phosphoric acid-propylene glycol was tested as a chill tank additive in experiments simulating commercial broiler chilling. In bench-scale experiments, 0.5% T-128 was compared with plain water (control), 50 ppm of chlorine, and the combination of 0.5% T-128 with 50 ppm of chlorine to control transfer of Salmonella and Campylobacter from inoculated wing drummettes to co-chilled uninoculated drummettes. Both chlorine and T-128 lessened cross-contamination with Salmonella (P < 0.05); T-128 and T-128 with chlorine were significantly more effective (P < 0.05) than the control or plain chlorine for control of Campylobacter. T-128 treatments were noted to have a pH of less than 4.0; an additional experiment demonstrated that the antimicrobial effect of T-128 was not due merely to a lower pH. In commercial broiler chilling, a pH close to 6.0 is preferred to maximize chlorine effectiveness, while maintaining water-holding capacity of the meat. In a set of pilot-scale experiments with T-128, a near-ideal pH of 6.3 was achieved by using tap water instead of the distilled water used in bench-scale experiments. Pilot-scale chill tanks were used to compare the combination of 0.5% T-128 and 50 ppm of chlorine with 50 ppm of plain chlorine for control of cross-contamination between whole carcasses inoculated with Salmonella and Campylobacter and co-chilled uninoculated carcasses. The T-128 treatment resulted in significantly less crosscontamination by either direct contact or water transfer with both organisms compared with plain chlorine treatment. T-128 may have use in commercial broiler processing to enhance the effectiveness of chlorine in processing water.

  16. Casting process modeling using CAST2D: The part mold interface

    SciTech Connect

    Shapiro, A.B.

    1991-10-01

    Correctly modeling the physics across the part-mold interface is crucial in predicting the quality of a cast part. Most metals undergo a volume change on solidification (e.g., aluminum -6.6%) and shrinkage on cooling. As the cast metal shrinks, it pulls away from the mol wall creating a gap. This gap effects the thermal contact resistance between the part and mold. The thermal contact resistance increase as the gap widens. This directly effects the cooling rate and ultimately the final cast shape, stress state, and quality of the cast part. CAST2D is a coupled thermal-stress finite element computer code for casting process modeling. This code can be used to predict the final shape and stress state of cast parts. CAST2D couples the heat transfer code TOPAZ2D and solid mechanics code NIKE2D. CAST2D is a code in development. This report presents the status of a general purpose thermal-mechanical interface algorithm. 3 refs., 3 figs.

  17. Chilling outweighs photoperiod in preventing precocious spring development.

    PubMed

    Laube, Julia; Sparks, Tim H; Estrella, Nicole; Höfler, Josef; Ankerst, Donna P; Menzel, Annette

    2014-01-01

    It is well known that increased spring temperatures cause earlier onset dates of leaf unfolding and flowering. However, a temperature increase in winter may be associated with delayed development when species' chilling requirements are not fulfilled. Furthermore, photosensitivity is supposed to interfere with temperature triggers. To date, neither the relative importance nor possible interactions of these three factors have been elucidated. In this study, we present a multispecies climate chamber experiment to test the effects of chilling and photoperiod on the spring phenology of 36 woody species. Several hypotheses regarding their variation with species traits (successional strategy, floristic status, climate of their native range) were tested. Long photoperiods advanced budburst for one-third of the studied species, but magnitudes of these effects were generally minor. In contrast to prior hypotheses, photosensitive responses were not restricted to climax or oceanic species. Increased chilling length advanced budburst for almost all species; its effect greatly exceeding that of photoperiod. Moreover, we suggest that photosensitivity and chilling effects have to be rigorously disentangled, as the response to photoperiod was restricted to individuals that had not been fully chilled. The results indicate that temperature requirements and successional strategy are linked, with climax species having higher chilling and forcing requirements than pioneer species. Temperature requirements of invasive species closely matched those of native species, suggesting that high phenological concordance is a prerequisite for successful establishment. Lack of chilling not only led to a considerable delay in budburst but also caused substantial changes in the chronological order of species' budburst. The results reveal that increased winter temperatures might impact forest ecosystems more than formerly assumed. Species with lower chilling requirements, such as pioneer or invasive

  18. DuPage County chilled water storage project

    SciTech Connect

    Grumman, D.L.

    1998-10-01

    Between 1992 and 1995, the DuPage County Governmental Center in Wheaton, Illinois, commissioned a detailed analysis of its chilled water plant and distribution system, as well as its future needs and options for meeting those needs. The result was a 10,000 ton-hour (35,170 kWh) chilled water storage tank with associated components and controls. This paper describes that process and the system that resulted.

  19. Expandable pattern casting research

    NASA Astrophysics Data System (ADS)

    1993-09-01

    The Expandable Pattern Casting (EPC) Process is a developing foundry technology that allows designers the opportunity to consolidate parts, reduce machining, and minimize assembly operations. An air gauging system was developed for measuring foam patterns; exact shrinkage depended on type and density of the foam. Compaction studies showed that maximum sand densities in cavities and under overhangs are achieved with vibrational amplitudes 0.001-0.004 in., and that sand moved most freely within a few inches of the top free surface. Key to complete mold filling while minimizing casting defects lies in removing the foam decomposition products. The most precise iron castings were made by EPC in four commercial EPC foundries, with attention paid to molding and compaction. EP cast 60-45-12 ductile iron had yield strengths, ultimate strengths, and elastic modulus similar to conventionally cast ductile iron cast from the same ladle.

  20. SLIP CASTING METHOD

    DOEpatents

    Allison, A.G.

    1959-09-01

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

  1. Assay of Chilling Injury in Wild and Domestic Tomatoes Based on Photosystem Activity of the Chilled Leaves

    PubMed Central

    Smillie, Robert M.; Nott, Robyn

    1979-01-01

    Tomato leaves were detached and stored at 0 C for various periods of time. Chloroplasts were isolated from the leaves and their photoreductive activities were determined. Comparisons were made between two altitudinal forms of the wild tomato Lycopersicon hirsutum Humb. and Bonpl. (a tropical lowlands form and a highlands form adapted to growth at 3,100 meters), and two cultivars of the domestic tomato L. esculentum Mill. In each case the capacity of the isolated chloroplasts to photoreduce ferricyanide declined linearly with time of storage of the leaves at 0 C, but not at 10 C. This injury developed more slowly in the high altitudinal form of the wild tomato compared with the low altitudinal form and the two domestic cultivars indicating an enhanced resistance toward chilling injury in the tomato from 3,100 meters. Chloroplast activity declined in green tomato fruit held at 0 C, at about the same rate as in the chilled leaves. Measurements of photochemical activities in the isolated chloroplasts and in vivo measurements of cytochrome-554 photooxidation in chilled leaves showed that the site of action of the chilling effect was water donation to photosystem II. The chilling-induced impairment of photoreductive activity in chloroplasts provides a useful assay for detecting and measuring differences in the susceptibility of plants to chilling injury. PMID:16660815

  2. The Chilling Effect: How Do Researchers React to Controversy?

    PubMed Central

    Kempner, Joanna

    2008-01-01

    Background Can political controversy have a “chilling effect” on the production of new science? This is a timely concern, given how often American politicians are accused of undermining science for political purposes. Yet little is known about how scientists react to these kinds of controversies. Methods and Findings Drawing on interview (n = 30) and survey data (n = 82), this study examines the reactions of scientists whose National Institutes of Health (NIH)-funded grants were implicated in a highly publicized political controversy. Critics charged that these grants were “a waste of taxpayer money.” The NIH defended each grant and no funding was rescinded. Nevertheless, this study finds that many of the scientists whose grants were criticized now engage in self-censorship. About half of the sample said that they now remove potentially controversial words from their grant and a quarter reported eliminating entire topics from their research agendas. Four researchers reportedly chose to move into more secure positions entirely, either outside academia or in jobs that guaranteed salaries. About 10% of the group reported that this controversy strengthened their commitment to complete their research and disseminate it widely. Conclusions These findings provide evidence that political controversies can shape what scientists choose to study. Debates about the politics of science usually focus on the direct suppression, distortion, and manipulation of scientific results. This study suggests that scholars must also examine how scientists may self-censor in response to political events. PMID:19018657

  3. Casting process modeling using ProCAST and CAST2D -- Mold filling, solidification and structural response

    SciTech Connect

    Stein, W.; Shapiro, A.B.

    1992-04-01

    Correctly modeling the fluid flow and heat transfer during the filling of a mold with a molten fluid is important in predicting the quality of a cast part. Determining the dynamics of the flow and the free surface shape during filling are essential in establishing the temperature gradients in the melt and in the mold. After filling the mold, solidification may be greatly affected by natural convection effects. Further, correctly modeling the physics across the solidifying part-mold interface is crucial in predicting the part final shape. Most metals undergo a volume change on solidification (e.g. aluminum-6.6%) and shrinkage on cooling. As the cast metal shrinks, it pulls away from the mold wall creating a gap. This gap affects the thermal contact resistance between the part and mold. The thermal contact resistance increases as the gap widens. This directly affects the cooling rate and ultimately the final cast shape, stress state, and quality of the cast part.

  4. Tomato expressing Arabidopsis glutaredoxin gene AtGRXS17 confers tolerance to chilling stress via modulating cold responsive components

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chilling stress is a production constraint of tomato, a tropical origin, chilling-sensitive horticultural crop. The development of chilling tolerant tomato thus has significant potential to impact tomato production. Glutaredoxins (GRXs) are ubiquitous oxidoreductases, which utilize the reducing powe...

  5. Casting-chill interface heat transfer during solidification of an aluminum alloy

    SciTech Connect

    Velasco, E.; Cano, S.; Valtierra, S.; Mojica, J.F.; Talamantes, J.; Colas, R.

    1999-08-01

    Unidirectional solidification tests on an aluminum alloy were conducted with a computer-controlled instrumented rig. The alloys employed in this study were poured into isolated ingot molds (made of recrystallized alumina and covered with ceramic fiber) placed on top of a steel plate, coated either with a graphite- or ceramic-based paint in order to avoid sticking or the material. Thermal evolution during the test was captured by type-K thermocouples placed at different positions in both the ingot and the plate. The bottom surface of the plate was either cooled with water or left to cool in air. The heat-transfer coefficients across the aluminum-steel interface were evaluated by means of a finite-difference model. It was concluded that the heat-transfer rate depends on the conditions at the interface, such as the type of coating used to protect the plate, and the solidification reactions occurring on the aluminum during its solidification.

  6. Expendable Pattern Casting Technology

    NASA Astrophysics Data System (ADS)

    1990-07-01

    The expendable pattern casting (EPC) process is a potential casting process breakthrough which could dramatically improve the competitiveness of the U.S. foundry industry. Cooperatively supported by U.S. Industry and the Department of Energy and managed by the American Foundrymen's Society, a project was started in May 1989 to develop and optimize expendable pattern casting technology. Four major tasks were conducted in the first phase of the project. Those tasks involved: (1) reviewing published literature to determine the major problems in the EPC process; (2) evaluating factors influencing sand flow and compaction; (3) evaluating and comparing casting precision obtained in the EPC process with that obtained in other processes; and (4) identifying critical parameters that control dimensional precision and defect formation in EP castings.

  7. Concurrent effects of cold and hyperkalaemia cause insect chilling injury.

    PubMed

    MacMillan, Heath A; Baatrup, Erik; Overgaard, Johannes

    2015-10-22

    Chilling injury and death are the ultimate consequence of low temperature exposure for chill susceptible insects, and low temperature tolerance is considered one of the most important factors determining insect distribution patterns. The physiological mechanisms that cause chilling injury are unknown, but chronic cold exposure that causes injury is consistently associated with elevated extracellular [K(+)], and cold tolerant insects possess a greater capacity to maintain ion balance at low temperatures. Here, we use the muscle tissue of the migratory locust (Locusta migratoria) to examine whether chill injury occurs during cold exposure or following return to benign temperature and we specifically examine if elevated extracellular [K(+)], low temperature, or a combination thereof causes cell death. We find that in vivo chill injury occurs during the cold exposure (when extracellular [K(+)] is high) and that there is limited capacity for repair immediately following the cold stress. Further, we demonstrate that that high extracellular [K(+)] causes cell death in situ, but only when experienced at low temperatures. These findings strongly suggest that that the ability to maintain ion (particularly K(+)) balance is critical to insect low temperature survival, and highlight novel routes of study in the mechanisms regulating cell death in insects in the cold.

  8. Concurrent effects of cold and hyperkalaemia cause insect chilling injury.

    PubMed

    MacMillan, Heath A; Baatrup, Erik; Overgaard, Johannes

    2015-10-22

    Chilling injury and death are the ultimate consequence of low temperature exposure for chill susceptible insects, and low temperature tolerance is considered one of the most important factors determining insect distribution patterns. The physiological mechanisms that cause chilling injury are unknown, but chronic cold exposure that causes injury is consistently associated with elevated extracellular [K(+)], and cold tolerant insects possess a greater capacity to maintain ion balance at low temperatures. Here, we use the muscle tissue of the migratory locust (Locusta migratoria) to examine whether chill injury occurs during cold exposure or following return to benign temperature and we specifically examine if elevated extracellular [K(+)], low temperature, or a combination thereof causes cell death. We find that in vivo chill injury occurs during the cold exposure (when extracellular [K(+)] is high) and that there is limited capacity for repair immediately following the cold stress. Further, we demonstrate that that high extracellular [K(+)] causes cell death in situ, but only when experienced at low temperatures. These findings strongly suggest that that the ability to maintain ion (particularly K(+)) balance is critical to insect low temperature survival, and highlight novel routes of study in the mechanisms regulating cell death in insects in the cold. PMID:26468241

  9. Primary arm spacing in chill block melt spun Ni-Mo alloys

    NASA Technical Reports Server (NTRS)

    Tewari, S. N.; Glasgow, T. K.

    1986-01-01

    Chill block melt spun ribbons of Ni-Mo binary alloys containing 8.0 to 41.8 wt % Mo have been prepared under carefully controlled processing conditions. The growth velocity has been determined as a function of distance from the quench surface from the observed ribbon thickness dependence on the melt puddle residence time. Primary arm spacings measured at the midribbon thickness locations show a dependence on growth velocity and alloy composition which is expected from dendritic growth models for binary alloys directionally solidified in a positive temperature gradient.

  10. Subcritical Measurements Multiple HEU Metal Castings

    SciTech Connect

    Mihalczo, John T; Archer, Daniel E; Wright, Michael C

    2008-01-01

    Experiments with the standard annular highly enriched uranium (HEU) metal castings at Y-12 were performed in which up to 5 castings ({approx}90kg) were assembled in a tightly packed array with minimal spacing between castings. The fission chain multiplication process was initiated by a time tagged {sup 253}Cf spontaneously fissioning neutron source or time and directionally tagged neutrons from a small portable DT neutron generator and the prompt neutron time behavior measured with plastic scintillation detectors sensitive the fast neutron (>1 MeV) and gamma ray without distinction. These experiments were performed to provide data to benchmark methods for the calculation of the prompt neutron time behavior. Previous measurements with a single casting have been reported. This paper presents the experimental results for multiple castings. The prompt time decay was obtained by time coincidence correlation measurements between the detectors and the time tagged neutron source emission (equivalent to randomly pulsed neutron measurements) and between pairs of plastic scintillation detectors (equivalent to a 2-detector Rossi-alpha measurement). These standard HEU storage castings at the Y-12 plant had 5.000-in-OD, 3.500-in-ID, masses between 17,636 and 17,996 g, impurity content of 992 ppm, density of 18.75 g/cm{sup 3} and average enrichment of 93.16 wt % {sup 235}U. The castings were in tight fitting 025-in.-thick, 8.0-in-high stainless steel (SS-304) cylindrical cans for contamination control which were 8.0 in high. One can had an inside diameter of 3.0 in so that the Cf source could be located on the axes of this casting. Four 1 x 1 x 6 in plastic scintillators with the long dimension perpendicular to axes of the castings and adjacent to the outer surface of the casting cans were used. The detectors were enclosed in 1/4.-in.-thick lead shields on four 1 x 6 surfaces and on the 1 x 1 surface. The small surface of the lead shield was adjacent to the steel table. The

  11. Prosthetic management of malpositioned implant using custom cast abutment.

    PubMed

    Chatterjee, Aishwarya; Ragher, Mallikarjuna; Patil, Sanket; Chatterjee, Debopriya; Dandekeri, Savita; Prabhu, Vishnu

    2015-08-01

    Two cases are reported with malpositioned implants. Both the implants were placed 6-7 months back. They had osseointegrated well with the surrounding bone. However, they presented severe facial inclination. Case I was restored with custom cast abutment with an auto polymerizing acrylic gingival veneer. Case II was restored with custom cast UCLA type plastic implant abutment. Ceramic was directly fired on the custom cast abutments. The dual treatment strategy resulted in functional and esthetic restorations despite facial malposition of the implants.

  12. Structure and Property Studies on Austempered and As-Cast Ausferritic Gray Cast Irons

    NASA Astrophysics Data System (ADS)

    Vadiraj, Aravind; Balachandran, G.; Kamaraj, M.

    2010-10-01

    A high-strength and wear-resistant alloyed gray iron with ausferritic microstructure on solidification directly from molten condition could be made in a Ni and Mo alloyed gray cast iron. The as-cast ausferritic cast iron was compared with two conventionally austempered gray iron with and without Ni and Mo additions. The various phase constitution and volume fractions were analyzed using optical, SEM and XRD analyses. The various aspects of the alloy chemistry and processing conditions have been correlated with the microstructure and mechanical properties obtained. The analysis showed that the Ni-Mo alloyed austempered gray iron and the directly as-cast austempered gray iron had similar phase constitutions. The strength of the direct as-cast alloy with ausferritic microstructure was higher than the others due to its higher austenite content and carbide distribution. The wear rate of the conventionally austempered Ni and Mo containing alloy and direct as-cast ausferritic alloys is 20% of the austempered gray iron without Ni and Mo with friction coefficient less than 0.4.

  13. Heat transport and solidification in the electromagnetic casting of aluminum alloys: Part II. Development of a mathematical model and comparison with experimental results

    NASA Astrophysics Data System (ADS)

    Prasso, D. C.; Evans, J. W.; Wilson, I. J.

    1995-02-01

    In this second article of a two-part series, a mathematical model for heat transport and solidification of aluminum in electromagnetic casting is developed. The model is a three-dimensional one but involves a simplified treatment of convective heat transport in the liquid metal pool. Heat conduction in the solid was thought to play a dominant role in heat transport, and the thermal properties of the two alloys used in measurements reported in Part I (AA 5182 and 3104) were measured independently for input to the model. Heat transfer into the water sprays impacting the sides of the ingot was approximated using a heat-transfer coefficient from direct chill casting; because this heat-transfer step appears not to be rate determining for solidification and cooling of most of the ingot, there is little inaccuracy involved in this approximation. Joule heating was incorporated into some of the computations, which were carried out using the finite element software FIDAP. There was good agreement between the computed results and extensive thermocouple measurements (reported in Part I) made on a pilot-scale caster at Reynolds Metals Company (Richmond, VA).

  14. Improved Humidity Sensing with the Chilled Mirror: Really?

    NASA Technical Reports Server (NTRS)

    Schmidlin, Francis J.; Zukor, Dorothy (Technical Monitor)

    2001-01-01

    Testing of the chilled mirror sensor was initiated at Wallops Island in 1997. The chilled mirror dew point system is integrated with the Sippican, Inc., MK2 radiosonde providing a relatively inexpensive instrument. Early tests suggested that better stratospheric humidity measurements might be available. But, recent tests with different configurations of the mirror's cooler indicated that the systems capability to cool to the very low dew point temperatures required in the stratosphere were not being met with the present system. Nonetheless, the present mirror technology, while still undergoing development gives better humidity information between 400 and 100 hPa than the current routine radiosonde sensor. Comparisons are given of the chilled mirror and the typical operational humidity sensors.

  15. Clean Metal Casting

    SciTech Connect

    Makhlouf M. Makhlouf; Diran Apelian

    2002-02-05

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

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

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

    INTERIOR VIEW WITH LARGE PIPE CASTING MACHINE CASTING A 48' PIPE OPERATOR SPRAYING A POWDER TO HELP SOLIDIFY THE PIPE BEING CENTRIFUGALLY CAST. - United States Pipe & Foundry Company Plant, Pipe Casting & Testing Area, 2023 St. Louis Avenue at I-20/59, Bessemer, Jefferson County, AL

  17. Identification of chilling and heat requirements of cherry trees—a statistical approach

    NASA Astrophysics Data System (ADS)

    Luedeling, Eike; Kunz, Achim; Blanke, Michael M.

    2013-09-01

    Most trees from temperate climates require the accumulation of winter chill and subsequent heat during their dormant phase to resume growth and initiate flowering in the following spring. Global warming could reduce chill and hence hamper the cultivation of high-chill species such as cherries. Yet determining chilling and heat requirements requires large-scale controlled-forcing experiments, and estimates are thus often unavailable. Where long-term phenology datasets exist, partial least squares (PLS) regression can be used as an alternative, to determine climatic requirements statistically. Bloom dates of cherry cv. `Schneiders späte Knorpelkirsche' trees in Klein-Altendorf, Germany, from 24 growing seasons were correlated with 11-day running means of daily mean temperature. Based on the output of the PLS regression, five candidate chilling periods ranging in length from 17 to 102 days, and one forcing phase of 66 days were delineated. Among three common chill models used to quantify chill, the Dynamic Model showed the lowest variation in chill, indicating that it may be more accurate than the Utah and Chilling Hours Models. Based on the longest candidate chilling phase with the earliest starting date, cv. `Schneiders späte Knorpelkirsche' cherries at Bonn exhibited a chilling requirement of 68.6 ± 5.7 chill portions (or 1,375 ± 178 chilling hours or 1,410 ± 238 Utah chill units) and a heat requirement of 3,473 ± 1,236 growing degree hours. Closer investigation of the distinct chilling phases detected by PLS regression could contribute to our understanding of dormancy processes and thus help fruit and nut growers identify suitable tree cultivars for a future in which static climatic conditions can no longer be assumed. All procedures used in this study were bundled in an R package (`chillR') and are provided as Supplementary materials. The procedure was also applied to leaf emergence dates of walnut (cv. `Payne') at Davis, California.

  18. Revised Wind Chill Index (The Development of a New Wind Chill Temperature Chart)

    SciTech Connect

    Bluestein, Maurice

    2002-04-10

    It had been known for many years that the original wind chill temperature charts used by the weather services of Canada and the U.S. were flawed. This speaker applied modern heat transfer principles to the Antarctic research that was the basis for the original charts to demonstrate that the temperatures were much too cold. He then proposed an alternative model that would more accurately depict the effect of wind in cold weather on exposed skin. Media attention and an internet conference sponsored in Canada prompted the U.S. Weather Service to initiate a program to update their charts. This speaker and a Canadian researcher who worked with a similar approach were charged with developing a new chart. An algorithm was completed and the new chart was put into effect in Canada in October and in the U.S. in November, 2001.

  19. Revised Wind Chill Index (The Development of a New Wind Chill Temperature Chart)

    SciTech Connect

    Bluestein, Maurice

    2009-04-10

    It had been known for many years that the original wind chill temperature charts used by the weather services of Canada and the U.S. were flawed. This speaker applied modern heat transfer principles to the Antarctic research that was the basis for the original charts to demonstrate that the temperatures were much too cold. He then proposed an alternative model that would more accurately depict the effect of wind in cold weather on exposed skin. Media attention and an internet conference sponsored in Canada prompted the U.S. Weather Service to initiate a program to update their charts. This speaker and a Canadian researcher who worked with a similar approach were charged with developing a new chart. An algorithm was completed and the new chart was put into effect in Canada in October and in the U.S. in November, 2001.

  20. Symptomatic stent cast.

    PubMed

    Keohane, John; Moore, Michael; O'Mahony, Seamus; Crosbie, Orla

    2008-02-01

    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.

  1. CASTING METHOD AND APPARATUS

    DOEpatents

    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.

  2. Cast shadows in wide perspective.

    PubMed

    Pont, Sylvia C; Wijntjes, Maarten W A; Oomes, Augustinus H J; van Doom, Andrea; van Nierop, Onno; de Ridder, Huib; Koenderink, Jan J

    2011-01-01

    We investigated the apparent spatial layout of cast shadows up to very wide fields of view. We presented up to 130 degrees wide images in which two 'flat poles' were standing on a green lawn under a cloudless blue sky on a sunny day. The poles threw sharp cast shadows on the green, of which one was fixed. The observer's task was to adjust the azimuth of the shadow of the other pole such that it fitted the scene. The source elevation was kept constant. The two cast shadows are, of course, parallel in physical space, but generically not in the picture plane because of the wide perspective. We found that observers made huge systematic errors, indicating that, generically, they fail to account for these perspective effects. The systematic deviations could be well described by a weighted linear combination of the directions in the picture plane and in the physical space, with weights that depended on the positions of, and distance between, the poles.

  3. 77 FR 12800 - Fresh and Chilled Atlantic Salmon From Norway: Revocation of Antidumping and Countervailing Duty...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-02

    ... of Five-Year (``Sunset'') Review, 76 FR 89 (January 3, 2011); Fresh and Chilled Atlantic Salmon From... Duty Order, 76 FR 70409 (November 14, 2011), and Fresh and Chilled Atlantic Salmon From Norway: Final... Antidumping and Countervailing Duty Orders: Fresh and Chilled Atlantic Salmon from Norway, 71 FR...

  4. PREFACE: MCWASP XIII: International Conference on Modeling of Casting, Welding and Advanced Solidification Processes

    NASA Astrophysics Data System (ADS)

    Ludwig, Andreas

    2012-07-01

    Due to fast-paced development in computer technologies during the last three decades, computer-based process modeling has become an important tool for the improvement of existing process technologies and the development of new, innovative technologies. With the help of numerical process simulations, complex and costly experimental trials can now be reduced to a minimum. For metallurgical processes in particular, computer simulations are of outstanding importance, as the flow and solidification of molten alloys or the formation of microstructure and defects can hardly be observed experimentally. Corresponding computer simulations allow us inside views into the key process phenomena and so offer great potential for optimization. In 1980 the conference series 'Modeling of Casting, Welding and Advanced Solidification Processes (MCWASP)' was started up, and has now been continued by holding the 13th international conference on 'Modeling of Casting, Welding and Advanced Solidification Processes', MCWASP XIII, in Schladming, Austria, from June 17-22 2012. Around 200 scientists from industry and academia, coming from 20 countries around the globe attended 78 oral and 50 poster presentations on different aspects of solidification-related modeling topics. Besides process-related sessions such as (i) Ingot and Shape Casting, (ii) Continuous Casting and Direct Chill Casting, (iii) Directional Solidification and Zone Melting, (iv) Welding, and (v) Centrifugal Casting, a larger focus was put on (vi) Experimental Investigation and In-Situ Observations. In recent years, this topic has been significantly strengthened as advanced synchrotron technologies allow fantastic in-situ observations of phenomena happening inside small metallic samples. These observations will definitely serve as a benchmark for the modeling community. Further macroscopic aspects of advanced solidification science were tackled in the sessions (vii) Electromagnetic Coupling, (viii) Thermomechanics, (ix

  5. Casting Characteristics of Aluminum Die Casting Alloys

    SciTech Connect

    Makhlouf M. Makhlouf; Diran Apelian

    2002-02-05

    The research program investigates the casting characteristics of selected aluminum die casting alloys. Specifically, the alloys' tendencies towards die soldering and sludge formation, and the alloys' fluidity and machinability are evaluated. It was found that: When the Fe and Mn contents of the alloy are low; caution has to be taken against possible die soldering. When the alloy has a high sludge factor, particularly a high level of Fe, measures must be taken to prevent the formation of large hardspots. For this kind of alloy, the Fe content should be kept at its lowest allowable level and the Mn content should be at its highest possible level. If there are problems in die filling, measures other than changing the alloy chemistry need to be considered first. In terms of alloy chemistry, the elements that form high temperature compounds must be kept at their lowest allowable levels. The alloys should not have machining problems when appropriate machining techniques and machining parameters are used.

  6. Method of casting aerogels

    SciTech Connect

    Poco, J.F.

    1993-09-07

    The invention describes a method for making monolithic castings of transparent silica aerogel with densities in the range from 0.001 g/cm[sup 3] to 0.6 g/cm[sup 3]. Various shapes of aerogels are cast in flexible polymer molds which facilitate removal and eliminate irregular surfaces. Mold dimensions are preselected to account for shrinkage of aerogel which occurs during the drying step of supercritical extraction of solvent. 2 figures.

  7. MOLDS FOR CASTING PLUTONIUM

    DOEpatents

    Anderson, J.W.; Miley, F.; Pritchard, W.C.

    1962-02-27

    A coated mold for casting plutonium comprises a mold base portion of a material which remains solid and stable at temperatures as high as the pouring temperature of the metal to be cast and having a thin coating of the order of 0.005 inch thick on the interior thereof. The coating is composed of finely divided calcium fluoride having a particle size of about 149 microns. (AEC)

  8. Method of casting aerogels

    DOEpatents

    Poco, John F.

    1993-01-01

    The invention describes a method for making monolithic castings of transparent silica aerogel with densities in the range from 0.001 g/cm.sup.3 to 0.6 g/cm.sup.3. Various shapes of aerogels are cast in flexible polymer molds which facilitate removal and eliminate irregular surfaces. Mold dimensions are preselected to account for shrinkage of alcogel which occurs during the drying step of supercritical extraction of solvent.

  9. 8. VIEW OF A MOLD FOR PRECISION CASTING. THE MOLD ...

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

    8. VIEW OF A MOLD FOR PRECISION CASTING. THE MOLD WAS USED IN FOUNDRY OPERATIONS THAT CAST PLUTONIUM EITHER AS INGOTS SUITABLE FOR ROLLING AND FURTHER WROUGHT PROCESSING OR INTO SHAPES AMENABLE TO DIRECT MACHINING OPERATIONS. (5/6/59) - Rocky Flats Plant, Plutonium Fabrication, Central section of Plant, Golden, Jefferson County, CO

  10. Mold with improved core for metal casting operation

    DOEpatents

    Gritzner, Verne B.; Hackett, Donald W.

    1977-01-01

    The present invention is directed to a mold containing an improved core for use in casting hollow, metallic articles. The core is formed of, or covered with, a layer of cellular material which possesses sufficient strength to maintain its structural integrity during casting, but will crush to alleviate the internal stresses that build up if the normal contraction during solidification and cooling is restricted.

  11. Land-based turbine casting initiative

    SciTech Connect

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

    1995-10-01

    The Advanced Turbine Systems (ATS) program has set goals which include a large-scale utility turbine efficiency that exceeds 60 percent (LHV) on natural gas and an industrial turbine system heat rate improvement of 15 percent. To meet these goals, technological advances developed for aircraft gas turbine engines need to be applied to land based gas turbines. These technological advances include: directionally solidified and single crystal castings, alloys tailored to exploit these microstructures, complex internal cooling schemes, and coatings. Equiaxed and directionally solidified castings are employed in current land based power generation equipment. These castings do not possess the ability to meet the efficiency targets as outlined above. The production use of premium single crystal components with complex internal cooling schemes in the latest generation of alloys is necessary to meet the ATS goals. However, at present, the use of single crystal components with complex internal cooling schemes is restricted to industrial sized or aeroderivative engines, and prototype utility sized components.

  12. A Winning Cast

    NASA Technical Reports Server (NTRS)

    2001-01-01

    Howmet Research Corporation was the first to commercialize an innovative cast metal technology developed at Auburn University, Auburn, Alabama. With funding assistance from NASA's Marshall Space Flight Center, Auburn University's Solidification Design Center (a NASA Commercial Space Center), developed accurate nickel-based superalloy data for casting molten metals. Through a contract agreement, Howmet used the data to develop computer model predictions of molten metals and molding materials in cast metal manufacturing. Howmet Metal Mold (HMM), part of Howmet Corporation Specialty Products, of Whitehall, Michigan, utilizes metal molds to manufacture net shape castings in various alloys and amorphous metal (metallic glass). By implementing the thermophysical property data from by Auburn researchers, Howmet employs its newly developed computer model predictions to offer customers high-quality, low-cost, products with significantly improved mechanical properties. Components fabricated with this new process replace components originally made from forgings or billet. Compared with products manufactured through traditional casting methods, Howmet's computer-modeled castings come out on top.

  13. Centrifugal Casting Features/Metallurgical Characterization of Aluminum Alloys

    SciTech Connect

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

    2008-02-15

    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)

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

    DOEpatents

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

    2002-01-01

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

  15. Influence of fused Silica and chills incorporation on Corrosion, Thermal and Chemical composition of ASTM A 494 M Grade Nickel alloy

    NASA Astrophysics Data System (ADS)

    Purushotham, G.; Hemanth, Joel

    2016-09-01

    A review of a host of relevant literature on the composites leads to some important observations on the gap that prevails for developing the composite with increased strength to weight ratio, improved thermal properties and reduced corrosion rate with the addition of fused SiO2 dispersoid for the nickel based alloy. In the arena of engineering, metallurgists look for techniques to improve the thermal, corrosion and chemical properties of the materials. In this connection an investigation has been carried out to fabricate and evaluate the corrosion, chemical and thermal properties of chilled composites consisting of nickel matrix with fused silica particles (size 40-150 μm) in the matrix. The main objective of the present research is to obtain fine grain Ni/SiO2 chilled sound composite having very good properties. The dispersoid added ranged from 3 to 12 wt. % in steps of 3%. The subsequent composites cast in molds containing metallic and non-metallic chill blocks (MS, SiC & Cu) were tested for their microstructure, chemical, thermal properties and corrosion behavior.

  16. Meaningful wind chill indicators derived from heat transfer principles.

    PubMed

    Brauner, N; Shacham, M

    1995-08-01

    The wind chill index (WCI) and the more widely used wind chill equivalent temperature represent an attempt to combine several weather-related variables (temperature, wind velocity and solar radiation) into a single index which can indicate human comfort. Since its introduction in 1945, the WCI has been criticized mainly on the ground that the underlying model does not comply with modern heat transfer theory. In spite of that, the WCI, "calibrated" to human comfort, has proven to be successful in predicting discomfort and tolerance of man to the cold. Nevertheless, neither the WCI nor the wind chill equivalent temperature can be actually measured and, therefore, without the additional 'calibration' they are meaningless. In this study we have shown that the WCI represents the instantaneous rate of heat loss from bare skin at the moment of exposure to the cold, and as such, it correlates reasonably well with measurable variables that represent a feeling of cold. Two new wind chill indicators have been introduced: exposed skin temperature and maximum exposure time. These indicators yield more information than the WCI provides, are measurable, have physical meaning and are based on established heat transfer principles. PMID:7558408

  17. Meaningful wind chill indicators derived from heat transfer principles.

    PubMed

    Brauner, N; Shacham, M

    1995-08-01

    The wind chill index (WCI) and the more widely used wind chill equivalent temperature represent an attempt to combine several weather-related variables (temperature, wind velocity and solar radiation) into a single index which can indicate human comfort. Since its introduction in 1945, the WCI has been criticized mainly on the ground that the underlying model does not comply with modern heat transfer theory. In spite of that, the WCI, "calibrated" to human comfort, has proven to be successful in predicting discomfort and tolerance of man to the cold. Nevertheless, neither the WCI nor the wind chill equivalent temperature can be actually measured and, therefore, without the additional 'calibration' they are meaningless. In this study we have shown that the WCI represents the instantaneous rate of heat loss from bare skin at the moment of exposure to the cold, and as such, it correlates reasonably well with measurable variables that represent a feeling of cold. Two new wind chill indicators have been introduced: exposed skin temperature and maximum exposure time. These indicators yield more information than the WCI provides, are measurable, have physical meaning and are based on established heat transfer principles.

  18. Meaningful wind chill indicators derived from heat transfer principles

    NASA Astrophysics Data System (ADS)

    Brauner, Neima; Shacham, M.

    1995-03-01

    The wind chill index (WCI) and the more widely used wind chill equivalent temperature represent an attempt to combine several weather-related variables (temperature, wind velocity and solar radiation) into a single index which can indicate human comfort. Since its introduction in 1945, the WCI has been criticized mainly on the ground that the underlying model does not comply with modern heat transfer theory. In spite of that, the WCI, “calibrated” to human comfort, has proven to be successful in predicting discomfort and tolerance of man to the cold. Nevertheless, neither the WCI nor the wind chill equivalent temperature can be actually measured and, therefore, without the additional ‘calibration’ they are meaningless. In this study we have shown that the WCI represents the instantaneous rate of heat loss from bare skin at the moment of exposure to the cold, and as such, it correlates reasonably well with measurable variables that represent a feeling of cold. Two new wind chill indicators have been introduced: exposed skin temperature and maximum exposure time. These indicators yield more information than the WCI provides, are measurable, have physical meaning and are based on established heat transfer principles.

  19. 77 FR 10772 - Fresh and Chilled Atlantic Salmon From Norway

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-23

    ..., 2011 (76 FR 166) and determined on April 8, 2011 that it would conduct full reviews (76 FR 22422, April..., 2011 (76 FR 38698). The hearing was held in Washington, DC, on November 30, 2011, and all persons who... COMMISSION Fresh and Chilled Atlantic Salmon From Norway Determination On the basis of the record...

  20. Chilling the Messenger: The Impact of Libel on Community Newspapers.

    ERIC Educational Resources Information Center

    Hansen, Elizabeth K.; Moore, Roy L.

    A study used a new attitude and behavioral scale for measuring the chilling effect--an undercurrent of fear with respect to publishing decisions--and to determine the impact, if any, of threatened or actual libel suits on community newspapers. The editors and/or publishers of all 167 newspapers in Kentucky with a circulation of less than 50,000…

  1. Imagining Citizenship as Friendship in "The Big Chill"

    ERIC Educational Resources Information Center

    Kaplan, Michael

    2005-01-01

    This essay stages a theoretically driven critique of Lawrence Kasdan's film "The Big Chill" as a productive example of a constitutive contradiction animating the liberal political imaginary. In particular, it argues that liberalism relies irreducibly on an under-examined conception of friendship to supply its model of citizenship as a distinctive,…

  2. An approach to the determination of winter chill requirements for different Ribes cultivars.

    PubMed

    Jones, H G; Hillis, R M; Gordon, S L; Brennan, R M

    2013-01-01

    Winter chilling is critical for flowering and fruiting of many temperate fruits, with evidence that blackcurrant (Ribes nigrum L.) cropping has been adversely affected by warm winters. Accurate models of chill accumulation in blackcurrant are required so that breeding strategies can be formulated for the generation of new cultivars with resilience to future climates. Existing models for chill accumulation have largely been derived from statistical correlation; here we report the derivation of improved models for blackcurrant using controlled environment treatments. Hardwood cuttings from a diverse set of cultivars were exposed to constant or varying chilling temperatures and the effects on bud break after transfer to a warm, permissive environment evaluated. The impact of different combinations of temperature and chilling periods were described in terms of their overall 'Effectiveness' (E). Clear genotypic differences were found, with excessive chilling often inhibiting bud break. There was a significant interaction between observed chilling response and the period of low temperature exposure. A number of chilling models to explain observed interactions between chilling temperature and time of exposure on bud break were compared; the most effective involved an optimal response to increasing chill accumulation. The effects of varying temperatures during chilling on bud break were complex, with warm temperature breaks substantially inhibiting bud development and cooler temperature breaks tending to enhance bud burst. The relevance of these models to generic studies of endodormancy is discussed, together with their potential application to the development of phenotyping screens for future breeding using diverse blackcurrant germplasm.

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

    NASA Astrophysics Data System (ADS)

    Wróbel, Tomasz

    2014-05-01

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

  4. In-situ conditioning of a strip casting roll

    DOEpatents

    Williams, Robert S.; Campbell, Steven L.

    1997-01-01

    A strip caster (10) for producing a continuous strip (24) has a tundish (12) for containing a melt (14) and a pair of horizontally disposed water cooled casting rolls (22). The casting rolls are juxtaposed relative to one another for forming a pouring basin (18) for receiving the melt through a teeming tube (16) thereby establishing a meniscus (20) between the rolls for forming a strip (24). The melt is protected from the outside air by a non-oxidizing gas passed through a supply line (28) to a sealing chamber (26). Devices (29) for conditioning the outer peripheral chill surfaces of the casting rolls includes grit blasting nozzles (30A, 30B, 30C, 30D), a collection trough (32) for gathering the grit, a line (34) for recycling the grit to a bag house (36), a feeder (38) and a pressurized distributor (40) for delivering the grit to the nozzles. The conditioning nozzles remove dirt, metal oxides and surface imperfections providing a clean surface readily wetted by the melt.

  5. In-situ conditioning of a strip casting roll

    DOEpatents

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

    1997-07-29

    A strip caster (10) for producing a continuous strip (24) has a tundish (12) for containing a melt (14) and a pair of horizontally disposed water cooled casting rolls (22). The casting rolls are juxtaposed relative to one another for forming a pouring basin (18) for receiving the melt through a teeming tube (16) thereby establishing a meniscus (20) between the rolls for forming a strip (24). The melt is protected from the outside air by a non-oxidizing gas passed through a supply line (28) to a sealing chamber (26). Devices (29) for conditioning the outer peripheral chill surfaces of the casting rolls includes grit blasting nozzles (30A, 30B, 30C, 30D), a collection trough (32) for gathering the grit, a line (34) for recycling the grit to a bag house (36), a feeder (38) and a pressurized distributor (40) for delivering the grit to the nozzles. The conditioning nozzles remove dirt, metal oxides and surface imperfections providing a clean surface readily wetted by the melt.

  6. A Thermal Simulation Method for Solidification Process of Steel Slab in Continuous Casting

    NASA Astrophysics Data System (ADS)

    Zhong, Honggang; Chen, Xiangru; Han, Qingyou; Han, Ke; Zhai, Qijie

    2016-07-01

    Eighty years after the invention of continuous cast of steels, reproducibility from few mm3 samples in the laboratory to m3 product in plants is still a challenge. We have engineered a thermal simulation method to simulate the continuous casting process. The temperature gradient (G L ) and dendritic growth rate (v) of the slab were reproduced by controlling temperature and cooling intensity at hot and chill end, respectively, in our simulation samples. To verify that our samples can simulate the cast slab in continuous casting process, the heat transfer, solidification structure, and macrosegregation of the simulating sample were compared to those of a much larger continuous casting slab. The morphology of solid/liquid interface, solidified shell thickness, and dendritic growth rate were also investigated by in situ quenching the solidifying sample. Shell thickness (δ) determined by our quenching experiment was related to solidification time (τ) by equation: δ = 4.27 × τ 0.38. The results indicated that our method closely simulated the solidification process of continuous casting.

  7. A Thermal Simulation Method for Solidification Process of Steel Slab in Continuous Casting

    NASA Astrophysics Data System (ADS)

    Zhong, Honggang; Chen, Xiangru; Han, Qingyou; Han, Ke; Zhai, Qijie

    2016-10-01

    Eighty years after the invention of continuous cast of steels, reproducibility from few mm3 samples in the laboratory to m3 product in plants is still a challenge. We have engineered a thermal simulation method to simulate the continuous casting process. The temperature gradient ( G L ) and dendritic growth rate ( v) of the slab were reproduced by controlling temperature and cooling intensity at hot and chill end, respectively, in our simulation samples. To verify that our samples can simulate the cast slab in continuous casting process, the heat transfer, solidification structure, and macrosegregation of the simulating sample were compared to those of a much larger continuous casting slab. The morphology of solid/liquid interface, solidified shell thickness, and dendritic growth rate were also investigated by in situ quenching the solidifying sample. Shell thickness ( δ) determined by our quenching experiment was related to solidification time ( τ) by equation: δ = 4.27 × τ 0.38. The results indicated that our method closely simulated the solidification process of continuous casting.

  8. Directing 101.

    ERIC Educational Resources Information Center

    Pintoff, Ernest

    Providing an introduction to anyone considering directing as a field of study or career, this book takes a broad look at the process of directing and encourages students and professionals alike to look outside of the movie industry for inspiration. Chapters in the book discuss selecting and acquiring material; budgeting and financing; casting and…

  9. Modeling of thermomechanical and metallurgical phenomena in steel strip during hot direct rolling and runout table cooling of thin-cast slabs

    NASA Astrophysics Data System (ADS)

    Muojekwu, Cornelius Anaedu

    The present research was directed at adequate prediction of the temperature, deformation behavior (roll force, flow stress, strain and strain rate) and microstructural evolution (recovery, recrystallization, grain growth, austenite and ferrite grain sizes) during rolling in the Compact Strip Production (CSP) process, as well as the final mechanical properties of the hot rolled strips. This was accomplished with the aid of integrated process modeling, involving mathematical simulation, laboratory experiments and industrial campaigns. The study covered two conventional plain carbon steel grades, the A36 (AISI 1018, 0.17C-0.74Mn) and DQSK (AISI 1005, 0.038C-0.3Mn), and a range of plain carbon steel grades (0.06-0.09 C, 0.16-0.9 Mn) produced at HYLSA's CSP mill at Monterrey, Mexico. In the laboratory, compression tests (both single and double-hits) were carried out on the Gleeble 1500 thermomechanical simulator in order to elucidate the effect of coarse austenite grain size on the flow stress and recrystallization behavior of the plain carbon steels. It was found that coarse grain size not only decreased the flow stress at a given strain but also substantially reduced the tendency toward dynamic recrystallization. An increase in grain size from 244 to 1110 mum which is typical of the first stands of a conventional finishing mill and CSP hot-strip mill respectively, resulted in up to a 30 MPa decrease in the flow stress of both A36 and DQSK steel grades at similar operating conditions of temperature, strain and strain rate. In order to validate the model and laboratory results with mill measurements from an operating CSP plant, an industrial trial was carried out at HYLSA's CSP mill in Monterrey, Mexico. During the industrial campaign, intermediate temperature measurements were made, CSP slab and coil samples were acquired, and all measured and recorded mill data and practices were obtained. Comprehensive mathematical modeling of the rolling process was carried out

  10. Investment cast AISI H13 tooling for automotive applications

    SciTech Connect

    Maguire, M.C.; Baldwin, M.D.; Hochanadel, P.W.; Edwards, G.R.

    1995-07-01

    While many techniques exist for production of soft tooling, for die casting there is limited recent experience with cast tooling. The most common US alloy used for manufacture of die casting tooling is wrought AISI H13. If the performance of the cast material is comparable to the wrought counterpart, the use of investment cast HI 3 tooling directly from patterns made via rapid prototyping is of considerable interest. A metallurgical study of investment cast H13 was conducted to evaluate the mechanical behavior in simulated die casting applications. Variable thickness plate investment castings of AISI H13 hot work die steel were produced and characterized in the as-cast and heat-treated conditions. The characterization included light microscopy and mechanical testing. Wrought samples of standard and premium grade H13 were heat-treated and characterized similarly for comparison. Microstructural differences were observed in as-cast samples produced in different section thicknesses. Dendrite cell size and carbide morphology constituted the most prominent microstructural differences observed. After a full heat-treatment, microstructural differences between the wrought material and cast materials were slight regardless of section thickness.The mechanical properties of the cast and heat-treated material proved similar to the properties of the standard heat-treated wrought material. A thermal fatigue testing unit was to con-elate the heat checking susceptibility of H13 steel to its processing and consequent microstructural condition. Surface hardness decreased significantly with thermal cycling, and heat checking was observed in as few as 50 cycles. Thermal softening and thermal fatigue susceptibility were quantified and discussed relative to the microstructural conditions created by processing and heat-treatment. It was found that the premium grade wrought H13 steel provided the best overall resistance to heat checking.

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

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

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

  12. An accelerated clinical chairside technique for casting overdenture attachment copings.

    PubMed

    Scherer, Michael D; Campagni, Wayne V

    2011-11-01

    An accelerated technique for casting a direct-pattern post and core restoration for use in fixed prosthodontics has been previously described. Similar techniques for use in removable prosthodontics show potential for clinical use, specifically for the fabrication of radicular stud overdenture attachments and their corresponding copings. The procedure uses a chairside technique and readily available components to fabricate a direct, acrylic resin pattern combining the elements of a cast coping with a fixed radicular attachment. This pattern can subsequently be invested, cast, finished and polished, luted, and attached to the removable prosthesis in a single clinical appointment. PMID:22024184

  13. Method for casting polyethylene pipe

    NASA Technical Reports Server (NTRS)

    Elam, R. M., Jr.

    1973-01-01

    Short lengths of 7-cm ID polyethylene pipe are cast in a mold which has a core made of room-temperature-vulcanizable (RTV) silicone. Core expands during casting and shrinks on cooling to allow for contraction of the polyethylene.

  14. Tradeoffs between chilling and forcing in satisfying dormancy requirements for Pacific Northwest tree species

    PubMed Central

    Harrington, Constance A.; Gould, Peter J.

    2015-01-01

    Many temperate and boreal tree species have a chilling requirement, that is, they need to experience cold temperatures during fall and winter to burst bud normally in the spring. Results from trials with 11 Pacific Northwest tree species are consistent with the concept that plants can accumulate both chilling and forcing units simultaneously during the dormant season and they exhibit a tradeoff between amount of forcing and chilling. That is, the parallel model of chilling and forcing was effective in predicting budburst and well chilled plants require less forcing for bud burst than plants which have received less chilling. Genotypes differed in the shape of the possibility line which describes the quantitative tradeoff between chilling and forcing units. Plants which have an obligate chilling requirement (Douglas-fir, western hemlock, western larch, pines, and true firs) and received no or very low levels of chilling did not burst bud normally even with long photoperiods. Pacific madrone and western redcedar benefited from chilling in terms of requiring less forcing to promote bud burst but many plants burst bud normally without chilling. Equations predicting budburst were developed for each species in our trials for a portion of western North America under current climatic conditions and for 2080. Mean winter temperature was predicted to increase 3.2–5.5°C and this change resulted in earlier predicted budburst for Douglas-fir throughout much of our study area (up to 74 days earlier) but later budburst in some southern portions of its current range (up to 48 days later) as insufficient chilling is predicted to occur. Other species all had earlier predicted dates of budburst by 2080 than currently. Recent warming trends have resulted in earlier budburst for some woody plant species; however, the substantial winter warming predicted by some climate models will reduce future chilling in some locations such that budburst will not consistently occur earlier. PMID

  15. Casting Of Multilayer Ceramic Tapes

    NASA Technical Reports Server (NTRS)

    Collins, Earl R., Jr.

    1991-01-01

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

  16. Titan Casts Revealing Shadow

    NASA Astrophysics Data System (ADS)

    2004-05-01

    A rare celestial event was captured by NASA's Chandra X-ray Observatory as Titan -- Saturn's largest moon and the only moon in the Solar System with a thick atmosphere -- crossed in front of the X-ray bright Crab Nebula. The X-ray shadow cast by Titan allowed astronomers to make the first X-ray measurement of the extent of its atmosphere. On January 5, 2003, Titan transited the Crab Nebula, the remnant of a supernova explosion that was observed to occur in the year 1054. Although Saturn and Titan pass within a few degrees of the Crab Nebula every 30 years, they rarely pass directly in front of it. "This may have been the first transit of the Crab Nebula by Titan since the birth of the Crab Nebula," said Koji Mori of Pennsylvania State University in University Park, and lead author on an Astrophysical Journal paper describing these results. "The next similar conjunction will take place in the year 2267, so this was truly a once in a lifetime event." Animation of Titan's Shadow on Crab Nebula Animation of Titan's Shadow on Crab Nebula Chandra's observation revealed that the diameter of the X-ray shadow cast by Titan was larger than the diameter of its solid surface. The difference in diameters gives a measurement of about 550 miles (880 kilometers) for the height of the X-ray absorbing region of Titan's atmosphere. The extent of the upper atmosphere is consistent with, or slightly (10-15%) larger, than that implied by Voyager I observations made at radio, infrared, and ultraviolet wavelengths in 1980. "Saturn was about 5% closer to the Sun in 2003, so increased solar heating of Titan may account for some of this atmospheric expansion," said Hiroshi Tsunemi of Osaka University in Japan, one of the coauthors on the paper. The X-ray brightness and extent of the Crab Nebula made it possible to study the tiny X-ray shadow cast by Titan during its transit. By using Chandra to precisely track Titan's position, astronomers were able to measure a shadow one arcsecond in

  17. Analysis of gas chilling alternatives for Arctic pipelines

    SciTech Connect

    Dvoiris, A.; McMillan, D.K.; Taksa, B.

    1994-12-31

    The operation of buried natural gas pipelines in Arctic regions requires installation of gas chilling facilities at compressor stations. These facilities are required in order to cool compressed pipeline gases to temperatures below that of permanently frozen surrounding soil. If these pipeline gas temperatures are too high, the frozen ground around the pipelines will eventually thaw. This is undesirable for many reasons amongst which are ground settlement and possible catastrophic failure of the pipeline. This paper presents the results of a study which compared several alternative methods of gas chilling for possible application at one of the compressor stations on the proposed new Yamal-Center gas pipeline system in the Russian Arctic. This technical and economic study was performed by Gulf Interstate Engineering (GIE) for GAZPROM, the gas company in Russia that will own and operate this new pipeline system. Geotechnical, climatical and other information provided by GAZPROM, coupled with information developed by GIE, formed the basis for this study.

  18. Casting and Angling.

    ERIC Educational Resources Information Center

    Smith, Julian W.

    As part of a series of books and pamphlets on outdoor education, this manual consists of easy-to-follow instructions for fishing activities dealing with casting and angling. The manual may be used as a part of the regular physical education program in schools and colleges or as a club activity for the accomplished weekend fisherman or the…

  19. Extrusion cast explosive

    DOEpatents

    Scribner, Kenneth J.

    1985-01-01

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

  20. ShakeCast Manual

    USGS Publications Warehouse

    Lin, Kuo-Wan; Wald, David J.

    2008-01-01

    ShakeCast is a freely available, post-earthquake situational awareness application that automatically retrieves earthquake shaking data from ShakeMap, compares intensity measures against users? facilities, and generates potential damage assessment notifications, facility damage maps, and other Web-based products for emergency managers and responders.

  1. Mix/Cast Contamination Control

    NASA Technical Reports Server (NTRS)

    Wallentine, M.

    2005-01-01

    Presented is a training handbook for Mix/Cast Contamination Control; a part of a series of training courses to qualify access to Mix/Cast facilities. Contents: List Contamination Control Requirements; Identify foreign objects debris (FOD), Control Areas and their guidelines; Describe environmental monitoring; List Contamination Control Initiatives; Describe concern for Controlled Materials; Identify FOD Controlled Areas in Mix/Cast.

  2. Structure and properties of polypropylene cast films: Polymer type and processing effects

    NASA Astrophysics Data System (ADS)

    Mileva, Daniela; Gahleitner, Markus; Gloger, Dietrich

    2016-05-01

    The influence of processing parameters in a cast film extrusion process of thin films of isotactic polypropylene homopolymer and random propylene-ethylene copolymer was analyzed. Variation of the chill roll temperature allowed changing the supercooling of the melt and thus the generation of different crystal polymorphs of iPP. Additional focus was placed on the effect of flow induced crystallization via changing the output rate of the line. The crystal structure and morphology of the materials were evaluated and correlated to selected optical and mechanical properties.

  3. Chill-inducing music enhances altruism in humans

    PubMed Central

    Fukui, Hajime; Toyoshima, Kumiko

    2014-01-01

    Music is a universal feature of human cultures, and it has both fascinated and troubled many researchers. In this paper we show through the dictator game (DG) that an individual’s listening to preferred “chill-inducing” music may promote altruistic behavior that extends beyond the bounds of kin selection or reciprocal altruism. Participants were 22 undergraduate and postgraduate students who were divided into two groups, the in-group and the out-group, and they acted as dictators. The dictators listened to their own preferred “chill-inducing” music, to music they disliked, or to silence, and then played the DG. In this hypothetical experiment, the dictators were given real money (which they did not keep) and were asked to distribute it to the recipients, who were presented as stylized images of men and women displayed on a computer screen. The dictators played the DG both before and after listening to the music. Both male and female dictators gave more money after listening to their preferred music and less after listening to the music they disliked, whereas silence had no effect on the allocated amounts. The group to which the recipient belonged did not influence these trends. The results suggest that listening to preferred “chill-inducing” music promotes altruistic behavior. PMID:25389411

  4. Chill-inducing music enhances altruism in humans.

    PubMed

    Fukui, Hajime; Toyoshima, Kumiko

    2014-01-01

    Music is a universal feature of human cultures, and it has both fascinated and troubled many researchers. In this paper we show through the dictator game (DG) that an individual's listening to preferred "chill-inducing" music may promote altruistic behavior that extends beyond the bounds of kin selection or reciprocal altruism. Participants were 22 undergraduate and postgraduate students who were divided into two groups, the in-group and the out-group, and they acted as dictators. The dictators listened to their own preferred "chill-inducing" music, to music they disliked, or to silence, and then played the DG. In this hypothetical experiment, the dictators were given real money (which they did not keep) and were asked to distribute it to the recipients, who were presented as stylized images of men and women displayed on a computer screen. The dictators played the DG both before and after listening to the music. Both male and female dictators gave more money after listening to their preferred music and less after listening to the music they disliked, whereas silence had no effect on the allocated amounts. The group to which the recipient belonged did not influence these trends. The results suggest that listening to preferred "chill-inducing" music promotes altruistic behavior.

  5. "Chilled" pork--Part II. Consumer perception of sensory quality.

    PubMed

    Ngapo, T M; Riendeau, L; Laberge, C; Fortin, J

    2012-12-01

    The objective of this study was to compare consumer perception of the sensory quality of grilled Canadian pork destined for Japanese and domestic markets, with particular reference to export selection criteria imposed by Japanese importers and transportation conditions. Consumers from Quebec, Canada tasted local and export quality pork subjected to "chilled" (aged 43 days at -1.7 °C) or conventional ageing (5 days at 3.1 °C). Consumers' scores (out of 10) were higher (P<0.05) in the "chilled" than conventionally aged pork for tenderness (6.8 vs 5.7), juiciness (6.6 vs 6.0), taste liking (6.4 vs 5.9) and overall acceptability (6.7 vs 6.1). When informed that the conventionally aged, domestic quality pork was destined for the domestic market, consumer scores increased significantly (P<0.05). No effect of information was observed on the perception of the 'chilled' export quality meat, perhaps a consequence of the high sensory quality observed prior to labelling.

  6. Method and apparatus for planar drag strip casting

    DOEpatents

    Powell, J.C.; Campbell, S.L.

    1991-11-12

    The present invention is directed to an improved process and apparatus for strip casting. The combination of a planar flow casting nozzle positioned back from the top dead center position with an attached nozzle extension, provides an increased level of casting control and quality. The nozzle extension provides a means of containing the molten pool above the rotating substrate to increase the control of molten metal at the edges of the strip and increase the range of coating thicknesses which may be produced. The level of molten metal in the containment means is regulated to be above the level of melt supplying the casting nozzle which produces a condition of planar drag flow with the casting substrate prior to solidification. 5 figures.

  7. Method and apparatus for planar drag strip casting

    DOEpatents

    Powell, John C.; Campbell, Steven L.

    1991-01-01

    The present invention is directed to an improved process and apparatus for strip casting. The combination of a planar flow casting nozzle positioned back from the top dead center position with an attached nozzle extension, provides an increased level of casting control and quality. The nozzle extension provides a means of containing the molten pool above the rotating substrate to increase the control of molten metal at the edges of the strip and increase the range of coating thicknesses which may be produced. The level of molten metal in the containment means is regulated to be above the level of melt supplying the casting nozzle which produces a condition of planar drag flow with the casting substrate prior to solidification.

  8. Development of a thin steel strip casting process. Final report

    SciTech Connect

    Williams, R.S.

    1994-04-01

    This is a comprehensive effort to develop direct strip casting to the point where a pilot scale program for casting carbon steel strip could be initiated. All important aspects of the technology were being investigated, however the program was terminated early due to a change in the business strategy of the primary contractor, Armco Inc. (focus to be directed at specialty steels, not low carbon steel). At termination, the project was on target on all milestones and under budget. Major part was casting of strip at the experiment casting facility. A new caster, capable of producing direct cast strip of up to 12 in. wide in heats of 1000 and 3000 lb, was used. A total of 81 1000-1200 lb heats were cast as well as one test heat of 3000 lb. Most produced strip of from 0.016 to 0.085 in. thick. Process reliability was excellent for short casting times; quality was generally poor from modern hot strip mill standards, but the practices necessary for good surface quality were identified.

  9. Spall behavior of cast iron with varying microstructures

    SciTech Connect

    Plume, Gifford; Rousseau, Carl-Ernst

    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.

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

    SciTech Connect

    Prof. Alan W. Camb; Prof. Anthony Rollett

    2001-08-31

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

  11. Effect of dry-air chilling on sensory descriptive profiles of cooked broiler breast meat deboned four hours after the initiation of chilling.

    PubMed

    Zhuang, H; Savage, E M; Smith, D P; Berrang, M E

    2009-06-01

    The objective of this study was to evaluate the effect of a dry air-chilling (AC) method on sensory texture and flavor descriptive profiles of broiler pectoralis major (fillet) and pectoralis minor (tender). The profiles of the muscles immersion-chilled and deboned at the same postmortem time and the profiles of the muscles hot-boned (or no chill) were used for the comparison. A total of 108 eviscerated carcasses (6-wk-old broilers) were obtained from a commercial processing line before the chillers. Carcasses were transported to a laboratory facility where they were either i) chilled by a dry AC method (0.7 degrees C, 150 min in a cold room), ii) chilled by immersion chilling (IC; 0.3 degrees C, 50 min in a chiller), or iii) not chilled (9 birds per treatment per replication). Both IC and AC fillets and tenders were removed from the bone at 4 h after the initiation of chilling (approximately 4.75 h postmortem) in a processing area (18 degrees C). The no-chill muscles were removed immediately upon arrival. The sensory properties (21 attributes) of cooked broiler breast meat were evaluated by trained panelists using 0- to 15-point universal intensity scales. The average intensity scores of the 9 flavor attributes analyzed ranged from 0.9 to 4.0. Regardless of breast muscle type, there were no significant differences in sensory flavor descriptive profiles between the 3 treatments. The average intensity scores of the 12 texture attributes ranged from 1.5 to 7.5 and there were no significant differences between the AC and IC samples. The average intensity scores of the texture attributes, cohesiveness, hardness, cohesiveness of mass, rate of breakdown, and chewiness of the no chill fillets and tenders were significantly higher than those of either of the chilled samples. These results demonstrate that chicken breast meat from AC retains sensory flavor profile characteristics but AC results in sensory texture profile differences when compared with no-chill meat. Sensory

  12. Dormancy release and chilling requirement of buds of latitudinal ecotypes of Betula pendula and B. pubescens.

    PubMed

    Myking, T; Heide, O M

    1995-11-01

    Bud burst and dormancy release of latitudinal ecotypes of Betula pendula Roth and B. pubescens Ehrh. from Denmark ( approximately 56 degrees N), mid-Norway ( approximately 64 degrees N) and northern Norway ( approximately 69 degrees N) were studied in controlled environments. Dormant seedlings were chilled at 0, 5 or 10 degrees C from October 4 onward and then, at monthly intervals from mid-November to February, batches of seedlings were held at 15 degrees C in an 8-h (SD) or 24-h (LD) photoperiod to permit flushing. A decline in days to bud burst occurred with increasing chilling time in all ecotypes. In November, after 44 chilling days, time to bud burst was least in plants chilled at 0 and 5 degrees C. The difference diminished with increasing chilling time, and in February, after 136 chilling days, bud burst was earliest in plants chilled at 10 degrees C. Long photoperiods during flushing significantly reduced thermal time after short chilling periods (44 and 74 days), but had no effect when the chilling requirement was fully met after 105 or more chilling days. No significant difference in these responses was found between the two species. In both species, chilling requirement decreased significantly with increasing latitude of origin. Bud burst was normal in seedlings overwintered at 12 degrees C, but was erratic and delayed in seedlings overwintered at 15 and especially at 21 degrees C, indicating that the critical overwintering temperature is between 12 and 15 degrees C. We conclude that there is little risk of a chilling deficit in birch under Scandinavian winter conditions even with a climatic warming of 7-8 degrees C. The likely effects of a climatic warming include earlier bud burst, a longer growing season and increased risk of spring frost injury, especially in high latitude ecotypes. PMID:14965987

  13. My shadow, myself: cast-body shadows are embodied.

    PubMed

    Kuylen, Christopher; Balas, Benjamin; Thomas, Laura E

    2014-06-01

    Objects that serve as extensions of the body can produce a sensation of embodiment, feeling as if they are a part of us. We investigated the characteristics that drive an object's embodiment, examining whether cast-body shadows, a purely visual stimulus, are embodied. Tools are represented as an extension of the body when they enable observers to interact with distant targets, perceptually distorting space. We examined whether perceptual distortion would also result from exposure to cast-body shadows in two separate distance estimation perceptual matching tasks. If observers represent cast-body shadows as extensions of their bodies, then when these shadows extend toward a target, it should appear closer than when no shadow is present (Experiment 1). This effect should not occur when a non-cast-body shadow is cast toward a target (Experiment 2). We found perceptual distortions in both cast-body shadow and tool-use conditions, but not in our non-cast-body shadow condition. These results suggest that, although cast-body shadows do not enable interaction with objects or provide direct tactile feedback, observers nonetheless represent their shadows as if they were a part of them.

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

    SciTech Connect

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

    2011-01-17

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

  15. AMCC casting development, volume 2

    NASA Technical Reports Server (NTRS)

    1995-01-01

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

  16. Moderate Photoinhibition of Photosystem II Protects Photosystem I from Photodamage at Chilling Stress in Tobacco Leaves.

    PubMed

    Huang, Wei; Yang, Ying-Jie; Hu, Hong; Zhang, Shi-Bao

    2016-01-01

    It has been indicated that photosystem I (PSI) is susceptible to chilling-light stress in tobacco leaves, but the effect of growth light intensity on chilling-induced PSI photoinhibition in tobacco is unclear. We examined the effects of chilling temperature (4°C) associated with moderate light intensity (300 μmol photons m(-2) s(-1)) on the activities of PSI and photosystem II (PSII) in leaves from sun- and shade-grown plants of tobacco (Nicotiana tabacum cv. k326). The sun leaves had a higher activity of alternative electron flow than the shade leaves. After 4 h chilling treatment, the sun leaves showed significantly a higher PSI photoinhibition than the shade leaves. At chilling temperature the sun leaves showed a greater electron flow from PSII to PSI, accompanying with a lower P700 oxidation ratio. When leaves were pre-treated with lincomycin, PSII activity decreased by 42% (sun leaves) and 47% (shade leaves) after 2 h exposure to the chilling-light stress, but PSI activity remained stable during the chilling-light treatment, because the electron flow from PSII to PSI was remarkably depressed. These results indicated that the stronger chilling-induced PSI photoinhibition in the sun leaves was resulted from a greater electron flow from PSII to PSI. Furthermore, moderate PSII photoinhibition depressed electron flow to PSI and then protected PSI activity against further photodamage in chilled tobacco leaves. PMID:26941755

  17. Moderate Photoinhibition of Photosystem II Protects Photosystem I from Photodamage at Chilling Stress in Tobacco Leaves

    PubMed Central

    Huang, Wei; Yang, Ying-Jie; Hu, Hong; Zhang, Shi-Bao

    2016-01-01

    It has been indicated that photosystem I (PSI) is susceptible to chilling-light stress in tobacco leaves, but the effect of growth light intensity on chilling-induced PSI photoinhibition in tobacco is unclear. We examined the effects of chilling temperature (4°C) associated with moderate light intensity (300 μmol photons m-2 s-1) on the activities of PSI and photosystem II (PSII) in leaves from sun- and shade-grown plants of tobacco (Nicotiana tabacum cv. k326). The sun leaves had a higher activity of alternative electron flow than the shade leaves. After 4 h chilling treatment, the sun leaves showed significantly a higher PSI photoinhibition than the shade leaves. At chilling temperature the sun leaves showed a greater electron flow from PSII to PSI, accompanying with a lower P700 oxidation ratio. When leaves were pre-treated with lincomycin, PSII activity decreased by 42% (sun leaves) and 47% (shade leaves) after 2 h exposure to the chilling-light stress, but PSI activity remained stable during the chilling-light treatment, because the electron flow from PSII to PSI was remarkably depressed. These results indicated that the stronger chilling-induced PSI photoinhibition in the sun leaves was resulted from a greater electron flow from PSII to PSI. Furthermore, moderate PSII photoinhibition depressed electron flow to PSI and then protected PSI activity against further photodamage in chilled tobacco leaves. PMID:26941755

  18. [Climatic risk zoning for banana and litchi's chilling injury in South China].

    PubMed

    Li, Na; Huo, Zhi-guo; He, Nan; Xiao, Jing-jing; Wen, Quan-pei

    2010-05-01

    Based on the 1951-2006 climatic observation data from 224 meteorological stations in South China (Guangdong Province, Guangxi Autonomous Region, and Fujian Province) and the historical information about the chilling injury losses of banana and litchi, the accumulated harmful chilling for the processes with minimum daily temperature < or = 5.0 degrees C and more than 3 days was used to indicate the climatic risk of chilling injury during the whole growth season, and an integrated climatic index with the background of climate change was constructed. The maps of geographical distribution of climatic risk probability for each grade chilling injury, and of integrated climatic risk zoning for banana and litchi's chilling injury were drawn, and the spatial variation of climatic risk for banana and litchi's chilling injury was commented. The results indicated that in the study area, climate warming might lead to the decrease of cold resistance of banana and litchi, which could increase the disaster risk of chilling injury. The geographical distribution of climatic risk probability for banana and litchi's chilling injury showed a zonal pattern. According to the integrated climatic risk index, the banana and litchi's chilling injury region was divided into three risk types, i.e., high risk, moderate risk, and low risk, which provided an important basis for the adjustment of agricultural production structure.

  19. Textures in Strip-Cast Aluminum Alloys: Their On-Line Monitoring and Quantitative Effects on Formability. Final Technical Report

    SciTech Connect

    Man, Chi-Sing

    2003-07-27

    Aluminum sheets produced by continuous casting (CC) provide energy and economic savings of at least 25 and 14 percent, respectively, over sheets made from conventional direct chill (DC) ingot casting and rolling. As a result of the much simpler production route in continuous casting, however, the formability of CC aluminum alloys is often somewhat inferior to that of their DC counterparts. The mechanical properties of CC alloys can be improved by controlling their microstructure through optimal thermomechanical processing. Suitable annealing is an important means to improve the formability of CC aluminum alloy sheets. Recrystallization of deformed grains occurs during annealing, and it changes the crystallographic texture of the aluminum sheet. Laboratory tests in this project showed that this texture change can be detected by either laser-ultrasound resonance spectroscopy or resonance EMAT (electromagnetic acoustic transducer) spectroscopy, and that monitoring this change allows the degree of recrystallization or the ''recrystallized fraction'' in an annealed sheet to be ascertained. Through a plant trial conducted in May 2002, this project further demonstrated that it is feasible to monitor the recrystallized state of a continuous-cast aluminum sheet in-situ on the production line by using a laser-ultrasound sensor. When used in conjunction with inline annealing, inline monitoring of the recrystallized fraction by laser-ultrasound resonance spectroscopy offers the possibility of feed-back control that helps optimize processing parameters (e.g., annealing temperature), detect production anomalies, ensure product quality, and further reduce production costs of continuous-cast aluminum alloys. Crystallographic texture strongly affects the mechanical anisotropy/formability of metallic sheets. Clarification of the quantitative relationship between texture and anisotropy/formability of an aluminum alloy will render monitoring and control of its texture during the sheet

  20. Melting and casting of FeAl-based cast alloy

    SciTech Connect

    Sikka, V.K.; Wilkening, D.; Liebetrau, J.; Mackey, B.

    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.

  1. Bioinspired Design: Magnetic Freeze Casting

    NASA Astrophysics Data System (ADS)

    Porter, Michael Martin

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

  2. Volume MLS ray casting.

    PubMed

    Ledergerber, Christian; Guennebaud, Gaël; Meyer, Miriah; Bächer, Moritz; Pfister, Hanspeter

    2008-01-01

    The method of Moving Least Squares (MLS) is a popular framework for reconstructing continuous functions from scattered data due to its rich mathematical properties and well-understood theoretical foundations. This paper applies MLS to volume rendering, providing a unified mathematical framework for ray casting of scalar data stored over regular as well as irregular grids. We use the MLS reconstruction to render smooth isosurfaces and to compute accurate derivatives for high-quality shading effects. We also present a novel, adaptive preintegration scheme to improve the efficiency of the ray casting algorithm by reducing the overall number of function evaluations, and an efficient implementation of our framework exploiting modern graphics hardware. The resulting system enables high-quality volume integration and shaded isosurface rendering for regular and irregular volume data.

  3. Extrusion cast explosive

    DOEpatents

    Scribner, K.J.

    1985-11-26

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

  4. Extrusion cast explosive

    DOEpatents

    Scribner, K.J.

    1985-01-29

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

  5. USGS ShakeCast

    USGS Publications Warehouse

    Wald, David; Lin, Kuo-Wan

    2007-01-01

    Automating, Simplifying, and Improving the Use of ShakeMap for Post-Earthquake Decisionmaking and Response. ShakeCast is a freely available, post-earthquake situational awareness application that automatically retrieves earthquake shaking data from ShakeMap, compares intensity measures against users facilities, and generates potential damage assessment notifications, facility damage maps, and other Web-based products for emergency managers and responders.

  6. Exogenous Melatonin Improves Antioxidant Defense in Cucumber Seeds (Cucumis sativus L.) Germinated under Chilling Stress.

    PubMed

    Marta, Bałabusta; Szafrańska, Katarzyna; Posmyk, Małgorzata M

    2016-01-01

    The relationship between exogenous melatonin applied into cucumber seeds during osmopriming and modifications of their antioxidant defense was studied. Accumulation of hydrogen peroxide, antioxidant enzyme activities and glutathione pool were investigated in embryonic axes isolated from the control, osmoprimed, and osmoprimed with melatonin seeds. Germinating cucumber seeds are very sensitive to chilling. Temperature 10°C causes oxidative stress in young seedlings. Seed pre-treatment with melatonin seemed to limit H2O2 accumulation during germination under optimal condition as well as during chilling stress and recovery period. Melatonin affected superoxide dismutase (SOD) activity and its isoforms during stress and recovery period but did not influence CAT and POX activities. Thus it is possible that in cucumber this indoleamine could act mostly as a direct H2O2 scavenger, but superoxide anion combat via SOD stimulation. The GSH/GSSG ratio is considered as an indirect determinant of oxidative stress. When the cells are exposed to oxidative stress GSSG is accumulated and the ratio of GSH to GSSG decreases. In our research pre-sowing melatonin application into the cucumber seeds caused high beneficial value of GSH/GSSG ratio that could be helpful for stress countering. Glutathione reductase (GSSG-R) activity in the axes isolated from these seeds was two fold higher than in those isolated from the control and from the osmoprimed without melatonin ones. Additional isoforms of GSSG-R in melatonin treated seeds were also observed. It explains high and effective GSH pool restoration in the seeds pre-treated with melatonin. We confirmed that melatonin could protect cucumber seeds and young seedlings against oxidative stress directly and indirectly detoxifying ROS, thereby plants grown better even in harmful environmental conditions. This work is the first that investigated on plant in vivo model and documented melatonin influence on redox state during seed germination

  7. Exogenous Melatonin Improves Antioxidant Defense in Cucumber Seeds (Cucumis sativus L.) Germinated under Chilling Stress.

    PubMed

    Marta, Bałabusta; Szafrańska, Katarzyna; Posmyk, Małgorzata M

    2016-01-01

    The relationship between exogenous melatonin applied into cucumber seeds during osmopriming and modifications of their antioxidant defense was studied. Accumulation of hydrogen peroxide, antioxidant enzyme activities and glutathione pool were investigated in embryonic axes isolated from the control, osmoprimed, and osmoprimed with melatonin seeds. Germinating cucumber seeds are very sensitive to chilling. Temperature 10°C causes oxidative stress in young seedlings. Seed pre-treatment with melatonin seemed to limit H2O2 accumulation during germination under optimal condition as well as during chilling stress and recovery period. Melatonin affected superoxide dismutase (SOD) activity and its isoforms during stress and recovery period but did not influence CAT and POX activities. Thus it is possible that in cucumber this indoleamine could act mostly as a direct H2O2 scavenger, but superoxide anion combat via SOD stimulation. The GSH/GSSG ratio is considered as an indirect determinant of oxidative stress. When the cells are exposed to oxidative stress GSSG is accumulated and the ratio of GSH to GSSG decreases. In our research pre-sowing melatonin application into the cucumber seeds caused high beneficial value of GSH/GSSG ratio that could be helpful for stress countering. Glutathione reductase (GSSG-R) activity in the axes isolated from these seeds was two fold higher than in those isolated from the control and from the osmoprimed without melatonin ones. Additional isoforms of GSSG-R in melatonin treated seeds were also observed. It explains high and effective GSH pool restoration in the seeds pre-treated with melatonin. We confirmed that melatonin could protect cucumber seeds and young seedlings against oxidative stress directly and indirectly detoxifying ROS, thereby plants grown better even in harmful environmental conditions. This work is the first that investigated on plant in vivo model and documented melatonin influence on redox state during seed germination

  8. Exogenous Melatonin Improves Antioxidant Defense in Cucumber Seeds (Cucumis sativus L.) Germinated under Chilling Stress

    PubMed Central

    Marta, Bałabusta; Szafrańska, Katarzyna; Posmyk, Małgorzata M.

    2016-01-01

    The relationship between exogenous melatonin applied into cucumber seeds during osmopriming and modifications of their antioxidant defense was studied. Accumulation of hydrogen peroxide, antioxidant enzyme activities and glutathione pool were investigated in embryonic axes isolated from the control, osmoprimed, and osmoprimed with melatonin seeds. Germinating cucumber seeds are very sensitive to chilling. Temperature 10°C causes oxidative stress in young seedlings. Seed pre-treatment with melatonin seemed to limit H2O2 accumulation during germination under optimal condition as well as during chilling stress and recovery period. Melatonin affected superoxide dismutase (SOD) activity and its isoforms during stress and recovery period but did not influence CAT and POX activities. Thus it is possible that in cucumber this indoleamine could act mostly as a direct H2O2 scavenger, but superoxide anion combat via SOD stimulation. The GSH/GSSG ratio is considered as an indirect determinant of oxidative stress. When the cells are exposed to oxidative stress GSSG is accumulated and the ratio of GSH to GSSG decreases. In our research pre-sowing melatonin application into the cucumber seeds caused high beneficial value of GSH/GSSG ratio that could be helpful for stress countering. Glutathione reductase (GSSG-R) activity in the axes isolated from these seeds was two fold higher than in those isolated from the control and from the osmoprimed without melatonin ones. Additional isoforms of GSSG-R in melatonin treated seeds were also observed. It explains high and effective GSH pool restoration in the seeds pre-treated with melatonin. We confirmed that melatonin could protect cucumber seeds and young seedlings against oxidative stress directly and indirectly detoxifying ROS, thereby plants grown better even in harmful environmental conditions. This work is the first that investigated on plant in vivo model and documented melatonin influence on redox state during seed germination

  9. Chilled Mirror Dew Point Hygrometer (CM) Handbook

    SciTech Connect

    Ritsche, MT

    2005-01-01

    The CM systems have been developed for the ARM Program to act as a moisture standard traceable to National Institute of Standards and Technology (NIST). There are three CM systems that are each fully portable, self-contained, and require only 110 V AC power. The systems include a CM sensor, air sampling and filtration system, a secondary reference (Rotronic HP043 temperature and relative humidity sensor) to detect system malfunctions, a data acquisition system, and data storage for more than one month of 1-minute data. The CM sensor directly measures dew point temperature at 1 m, air temperature at 2 m, and relative humidity at 2 m. These measurements are intended to represent self-standing data streams that can be used independently or in combinations.

  10. Prosthetic management of malpositioned implant using custom cast abutment

    PubMed Central

    Chatterjee, Aishwarya; Ragher, Mallikarjuna; Patil, Sanket; Chatterjee, Debopriya; Dandekeri, Savita; Prabhu, Vishnu

    2015-01-01

    Two cases are reported with malpositioned implants. Both the implants were placed 6–7 months back. They had osseointegrated well with the surrounding bone. However, they presented severe facial inclination. Case I was restored with custom cast abutment with an auto polymerizing acrylic gingival veneer. Case II was restored with custom cast UCLA type plastic implant abutment. Ceramic was directly fired on the custom cast abutments. The dual treatment strategy resulted in functional and esthetic restorations despite facial malposition of the implants. PMID:26538957

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

    NASA Astrophysics Data System (ADS)

    Zhou, Weirong; Huang, Wei

    2015-07-01

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

  12. High density tape casting system

    NASA Technical Reports Server (NTRS)

    Collins, Earl R., Jr. (Inventor)

    1989-01-01

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

  13. Chilling tolerant U.S. processing cucumber (Cucumis sativus L.): three advanced backcross and ten inbred backcross lines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Environmental stresses such as chilling temperatures can reduce seed germination rate, seeding emergence rate, flower and fruit development, marketable yield, and postharvest fruit storage longevity in cucumber (Cucumis sativus L.). Chilling temperatures occur in unpredictable patterns, making it d...

  14. LOST FOAM CASTING OF MAGNESIUM ALLOYS

    SciTech Connect

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

    2007-01-01

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

  15. Cast dielectric composite linear accelerator

    DOEpatents

    Sanders, David M.; Sampayan, Stephen; Slenes, Kirk; Stoller, H. M.

    2009-11-10

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

  16. Diversity of low chill peaches from Asia, Brasil, Europe and the USA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    One hundred fifty-five peach (Prunus persica) cultivars, from Asia, Brazil, Europe, and the USA, were examined using eleven SSRs to study the genetic relationships among low chill as compared to high chill peach germplasm. Data was analyzed by NTSYSpc to form a similarity matrix using Nei and Li’s ...

  17. Investigation of hygiene aspects during air chilling of poultry carcases using a model rig.

    PubMed

    Allen, V M; Burton, C H; Corry, J E; Mead, G C; Tinker, D B

    2000-12-01

    1. An experimental rig, designed and built to simulate conditions found in commercial poultry chilling systems, was used to investigate the effects of varying air temperature and chilling duration, and the effect of chlorinated water sprays, on the microbial load present on the skin and in the body cavity of freshly eviscerated poultry carcases; deep muscle and skin temperatures were monitored during chilling at three different temperatures. 2. During dry chilling for 2 h, total viable microbe counts (TVC) and counts of coliforms and pseudomonads from the body cavity fell by between half and one log unit; smaller reductions were observed in samples from the breast skin. 3. The situation changed when chlorinated water sprays (50, 100 or 250 ppm available chlorine) were applied for the first hour of chilling; spraying carcases enhanced the reduction in numbers on the skin; the effect was most pronounced with 250 ppm chlorine; conversely in the body cavity, the general effects of sprays was to increase contamination by up to one log unit. 4. There was no evidence that sprays increased the rate of chilling. 5. When carcases were held overnight in the rig at 11 degrees C after chilling, microbe counts on dry-chilled carcases remained stable, but increased on carcases that had been sprayed with chlorinated water.

  18. Feeding impairs chill coma recovery in the migratory locust (Locusta migratoria).

    PubMed

    Andersen, Jonas Lembcke; Findsen, Anders; Overgaard, Johannes

    2013-10-01

    Low temperature causes loss of neuromuscular function in a wide range of insects, such that the animals enter a state known as chill coma. The ability to recover from chill coma (chill coma recovery time) is often a popular phenotype to characterise chill tolerance in insects. Chill coma in insects has been shown to be associated with a decrease in haemolymph volume and a marked increase in [K(+)], causing dissipation of K(+) equilibrium potential and resting membrane potential. High potassium diet (wheat) has also previously been shown to increase haemolymph [K(+)] in Locusta migratoria leading to sluggish behaviour. The present study combined these two independent stressors of ion and water homeostasis, in order to investigate the role of K(+)- and water-balance during recovery from chill coma, in the chill sensitive insect L. migratoria. We confirmed that cold shock elicits a fast increase in haemolymph [K(+)] which is likely caused by a water shift from the haemolymph to the muscles and other tissues. Recovery of haemolymph [K(+)] is however not only reliant on recovery of haemolymph volume, as the recovery of water and K(+) is decoupled. Chill coma recovery time, after 2h at -4 °C, differed significantly between fasted animals and those fed on high K(+) diet. This difference was not associated with an increased disturbance of haemolymph [K(+)] in the fed animals, instead it was associated with a slowed recovery of muscle [K(+)], muslce water, haemolymph [Na(+)] and K(+)equilibrium potential in the fed animals.

  19. Chills in Different Sensory Domains: Frisson Elicited by Acoustical, Visual, Tactile and Gustatory Stimuli

    ERIC Educational Resources Information Center

    Grewe, Oliver; Katzur, Bjorn; Kopiez, Reinhard; Altenmuller, Eckart

    2011-01-01

    "Chills" (frisson manifested as goose bumps or shivers) have been used in an increasing number of studies as indicators of emotions in response to music (e.g., Craig, 2005; Guhn, Hamm, & Zentner, 2007; McCrae, 2007; Panksepp, 1995; Sloboda, 1991). In this study we present evidence that chills can be induced through aural, visual, tactile, and…

  20. How does music arouse "chills"? Investigating strong emotions, combining psychological, physiological, and psychoacoustical methods.

    PubMed

    Grewe, Oliver; Nagel, Frederik; Kopiez, Reinhard; Altenmüller, Eckart

    2005-12-01

    Music can arouse ecstatic "chill" experiences defined as "goose pimples" and as "shivers down the spine." We recorded chills both via subjects' self-reports and physiological reactions, finding that they do not occur in a reflex-like manner, but as a result of attentive, experienced, and conscious musical enjoyment.

  1. 9 CFR 381.66 - Temperatures and chilling and freezing procedures.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 9 Animals and Animal Products 2 2013-01-01 2013-01-01 false Temperatures and chilling and freezing... Procedures § 381.66 Temperatures and chilling and freezing procedures. (a) General. Temperatures and... temperature is reduced to 40 °F. or less, as provided in paragraph (b)(2) of this section unless such...

  2. 9 CFR 381.66 - Temperatures and chilling and freezing procedures.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 9 Animals and Animal Products 2 2012-01-01 2012-01-01 false Temperatures and chilling and freezing... Procedures § 381.66 Temperatures and chilling and freezing procedures. (a) General. Temperatures and... temperature is reduced to 40 °F. or less, as provided in paragraph (b)(2) of this section unless such...

  3. 9 CFR 381.66 - Temperatures and chilling and freezing procedures.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 9 Animals and Animal Products 2 2011-01-01 2011-01-01 false Temperatures and chilling and freezing... Procedures § 381.66 Temperatures and chilling and freezing procedures. (a) General. Temperatures and... temperature is reduced to 40 °F. or less, as provided in paragraph (b)(2) of this section unless such...

  4. 9 CFR 381.66 - Temperatures and chilling and freezing procedures.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 9 Animals and Animal Products 2 2014-01-01 2014-01-01 false Temperatures and chilling and freezing... Procedures § 381.66 Temperatures and chilling and freezing procedures. (a) General. Temperatures and... temperature is reduced to 40 °F. or less, as provided in paragraph (b)(2) of this section unless such...

  5. Tomato chilling injury threshold defined by the volatile profiles of pink harvested tomato fruit

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fresh tomato fruit show visible symptoms of chilling injury (CI) when stored at temperatures lower than the reported chilling threshold of 12.5°C. However, their sensitivity has been reported to decrease as they ripen. Volatile profiles change during ripening and are affected by physiological change...

  6. The relationships between rheological properties and structural changes of chilled abalone meat

    NASA Astrophysics Data System (ADS)

    Xin, Gao; Zhaohui, Zhang; Zhixu, Tang; Yuri, Tashiro; Hiroo, Ogawa

    2003-10-01

    The quantitative correlation between rheological properties and structural characteristic values of chilled abalone meat was studied. Structural changes were observed, and these values were enumerated using image processing and analysis technique. Structural changes in the myofibrils and collagen fibrils were the greatest in chilling for 24 h. After chilling for 48 h, similar structures of vertical and cross sections were observed. For chilling from 0h to 72 h, the instantaneous modulus E 0 of the both section meat decreases gradually with time, but no significant differences were observed after chilling for 48h. The relaxation time and viscosity of both sections attained the same values for the same chilling time, but increased gradually with increasing chilling time. Meanwhile, a negative correlation between the structural characteristic values (Dm, Am, Rvm), and rheological properties (E 1, τ 1, η 1) clearly exists. Some logarithmic expressions have been obtained for these negative correlation. These results suggest that the difference in rheological properties between the cross and vertical sections was mainly due to the structural changes of myofibrils and collagen fibrils, and rheological properties are influenced quantitatively by the structural characteristics values for chilling from 0 h to 72 h.

  7. Salmonella Recovery Following Immersion Chilling for Matched Neck Skin and Whole Carcass Enrichment Sampling Methodologies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The prevalence and serogroups of Salmonella recovered following immersion chilling were determined for both neck skin and the matching whole carcass enriched samples. Commercially processed and eviscerated broiler carcasses were immersion chilled in ice and tap water for 40 min. Following immersio...

  8. 9 CFR 381.66 - Temperatures and chilling and freezing procedures.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Temperatures and chilling and freezing procedures. 381.66 Section 381.66 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT... Procedures § 381.66 Temperatures and chilling and freezing procedures. (a) General. Temperatures...

  9. Putative paternal factors controlling chilling tolerance in Korean market-type cucumber (Cucumis sativus L.)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chilling temperatures (<10 degrees C) may cause damage to Korean market-type cucumber (Cucumis sativus L.) plants during winter and early spring growing seasons. Inheritance to chilling in U.S. processing cucumber is controlled by cytoplasmic (maternally) and nuclear factors. To understand inherit...

  10. Chilling-Induced Lipid Degradation in Cucumber (Cucumis sativa L. cv Hybrid C) Fruit.

    PubMed

    Parkin, K L; Kuo, S J

    1989-07-01

    Chilling at 4 degrees C in the dark induced lipid degradation in cucumber (Cucumis sativa L.) fruit upon rewarming at 14 degrees C. Rates of ethane evolution by fruits rewarmed after 3 days of chilling were up to four-fold higher than those evolved by unchilled (14 degrees C) fruits (0.02-0.05 picomoles gram fresh weight(-1) hour(-1)). This potentiation of lipid peroxidation occurred prior to irreversible injury (requiring 3 to 7 days of chilling) as indicated by increases in ethylene evolution and visual observations. Decreases in unsaturation of peel tissue glycolipids were observed in fruits rewarmed after 3 days of chilling, indicating the plastids to be the site of the early phases of chilling-induced peroxidation. Losses in unsaturation of tissue phospholipids were first observed only after chilling for 7 days. Phospholipase D activity appeared to be potentiated in fruits rewarmed after 7 days of chilling as indicated by a decrease in phosphatidylcholine (and secondarily phosphatidylethanolamine) with a corresponding increase in phosphatidic acid. These results indicate that lipid peroxidation may have a role in conferring chilling injury.

  11. Salmonella recovery following air chilling for matched neck-skin and whole carcass sampling methodologies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The prevalence and serogroups of Salmonella recovered following air chilling were determined for both enriched neck skin and matching enriched whole carcass samples. Commercially processed and eviscerated carcasses were air chilled to 4C before removing the neck skin (8.3 g) and stomaching in 83 mL...

  12. Replacing London's cast iron mains

    SciTech Connect

    Thorne, A. ); Mathews, P. )

    1992-07-01

    This paper discusses the cast iron gas distribution systems that exist in many cities and contains considerable amounts of pipe that vary in age from 20 to 150 years. In many ways, cast iron is an excellent material. It is inherently corrosion resistant, easy to install and cheap. However, it is also brittle and smaller diameter cast iron pipe has a relatively low beam strength. This can lead, under some circumstances, to failure without external warning, with typically a full-circumferential failure. In congested areas this can lead to serious consequences. As a result, cast iron replacement programs are a common feature in such urban gas distribution systems.

  13. Cold resistance depends on acclimation and behavioral caste in a temperate ant

    NASA Astrophysics Data System (ADS)

    Modlmeier, Andreas P.; Pamminger, Tobias; Foitzik, Susanne; Scharf, Inon

    2012-10-01

    Adjusting to low temperatures is important for animals living in cold environments. We studied the chill-coma recovery time in temperate ant workers ( Temnothorax nylanderi) from colonies collected in autumn and spring in Germany. We experimentally acclimated these ant colonies to cold temperatures followed by warm temperatures. As expected, cold-acclimated workers recovered faster from freezing temperatures, but subsequent heat acclimation did not change the short recovery times observed after cold acclimation. Hence, either heat acclimation improves cold tolerance, possibly as a general response to stress, or at least it does not negate enhanced cold tolerance following cold acclimation. Colonies collected in spring showed similar cold tolerance levels to cold-acclimated colonies in the laboratory. Next, we compared the chill-coma recovery time of different worker castes and found that exterior workers recovered faster than interior workers. This difference may be related to their more frequent exposure to cold, higher activity level, or distinct physiology. Interior workers were also heavier and showed a higher gaster-to-head ratio and thorax ratio compared to exterior workers. An obvious difference between exterior and interior workers is activity level, but we found no link between activity and cold tolerance. This suggests that physiology rather than behavioral differences could cause the increased cold tolerance of exterior workers. Our study reveals the importance of acclimation for cold tolerance under natural and standardized conditions and demonstrates differences in cold tolerance and body dimensions in monomorphic behavioral castes of an ant.

  14. Anisotropic shrinkage characteristics of tape cast alumina

    NASA Astrophysics Data System (ADS)

    Patwardhan, Jaideep Suresh

    Dimensional control during sintering is a major issue in ceramics processing to avoid high post-sintering costs associated with machining of the fired ceramic part to desired tolerances and dimensions. Ceramic forming processes such as tape casting, injection molding, and extrusion involve shear of anisotropic particles resulting in preferential alignment of the particles in the green body. This preferential alignment causes directionality in mechanical, electrical, optical, and magnetic properties and most importantly warpage or distortion during sintering. A large effort has been devoted to synthesizing ceramic green bodies with minimal density gradients and uniform packing and modeling the sintering behavior evolution but little effort has been devoted to characterizing orientation of particles and the effect of preferential alignment on sintering shrinkage anisotropy. A systematic study was initiated to study the effect of processing variables such as shear rate, solids loading, temperature, and binder content on aqueous tape cast alumina. Three different alumina systems: A16-SG, Baikowski RC-UFX DBM and RC-LS DBM were investigated. Aqueous tapes of high solids loading alumina (56 vol. %) were tape cast at various speeds and thicknesses and assuming plane Couette flow a shear rate regime of 21--270 s-1 was investigated. Higher shear rates and high solids loading resulted in higher in-plane anisotropy whereas the anisotropy in the thickness direction was higher for low solids loading systems. The anisotropy was found to be fairly constant above a certain critical shear rate (˜100 s-1) irrespective of the temperature and the solids loading and this correlated with the viscosity-shear rate relationship of the cast slips. The higher shrinkage anisotropy in the thickness direction for the low solids loading systems (35 and 45 vol. %) was attributed to the higher amount of organics in the slip required to sustain the suitable viscosity for tape casting and

  15. The relationship of pattern position to the flow of gold and casting completeness.

    PubMed

    DeWald, E

    1979-05-01

    To minimize the possibility of incomplete casting due to improper pattern orientation relative to the sprue and direction of the casting arm motion, the following precautions should be taken. 1. Locate the pattern in the trailing half of the casting ring 90 to 135 degrees away from the sprue position. 2. Once the pattern is in the position described, locate it downward in the lower outer quarter of the trailing half of the casting ring and secure it in that position. 3. Mark the ring or sprue former so that the invested pattern can be oriented properly in the casting arm. 4. When using an electric casting machine, be certain that the pyrometer is correct. If in doubt, it is advisable to check the melt state of the gold before casting. PMID:374713

  16. A parametric study of wind chill equivalent temperatures by a dimensionless steady-state analysis

    NASA Astrophysics Data System (ADS)

    Shitzer, Avraham

    2006-03-01

    A first order analytical approximation of steady-state heat conduction in a hollow cylinder exchanging heat at its external surface by convection with a cold and windy environment is presented. The model depicts the thermal behavior of certain body elements, e.g., head/face, when exposed to such environments. The results are presented by dimensionless parameters and facilitate the estimation of wind chill equivalent temperatures (WCETs). The effects of several variables on determining WCETs were studied using specific examples, leading to the following generalizations: (1) the conditions assumed for "calm" wind speed appear to be a dominant factor in determining WCET; (2) the effects, on both (skin) surface temperature and on WCET, of a 1°C change in environmental temperature appear to be more pronounced than those of a 1 m/s change in wind speed; (3) similarly, predicted WCETs are more sensitive to the geometrical dimensions assumed for the modeled entity than they are to wind speeds; and (4) tissue thermal conductivity, the angle at which the convective heat transfer coefficient is measured relative to wind direction, and the factor used to establish "effective" wind speeds in the domain occupied by humans relative to reported values, all seem to have relatively small effects on the determination of WCET. These conclusions strongly suggest, among other things, that for any given combination of environmental conditions, wind chill indices may best be presented as ranges rather than as single values. This seems to apply even when worst-case scenarios are considered. Also emphasized is the need for careful and realistic selection of all the parameter values used in the determination of WCETs.

  17. A parametric study of wind chill equivalent temperatures by a dimensionless steady-state analysis.

    PubMed

    Shitzer, Avraham

    2006-03-01

    A first order analytical approximation of steady-state heat conduction in a hollow cylinder exchanging heat at its external surface by convection with a cold and windy environment is presented. The model depicts the thermal behavior of certain body elements, e.g., head/face, when exposed to such environments. The results are presented by dimensionless parameters and facilitate the estimation of wind chill equivalent temperatures (WCETs). The effects of several variables on determining WCETs were studied using specific examples, leading to the following generalizations: (1) the conditions assumed for "calm" wind speed appear to be a dominant factor in determining WCET; (2) the effects, on both (skin) surface temperature and on WCET, of a 1 degrees C change in environmental temperature appear to be more pronounced than those of a 1 m/s change in wind speed; (3) similarly, predicted WCETs are more sensitive to the geometrical dimensions assumed for the modeled entity than they are to wind speeds; and (4) tissue thermal conductivity, the angle at which the convective heat transfer coefficient is measured relative to wind direction, and the factor used to establish "effective" wind speeds in the domain occupied by humans relative to reported values, all seem to have relatively small effects on the determination of WCET. These conclusions strongly suggest, among other things, that for any given combination of environmental conditions, wind chill indices may best be presented as ranges rather than as single values. This seems to apply even when worst-case scenarios are considered. Also emphasized is the need for careful and realistic selection of all the parameter values used in the determination of WCETs.

  18. Solidification science in cast MMCs: The influence of merton flemings

    NASA Astrophysics Data System (ADS)

    Rohatgi, Pradeep; Asthana, Rajiv

    2001-09-01

    The solidification science of cast metalmatrix composites (MMC) evolved as a subset of the broad field of solidification of monolithic alloys pioneered by Merton Flemings and his students. As a result of advances in solidification, the cast MMC field has evolved from its early incarnation—employing empirical research to engineer novel materials using versatile and cost-effective casting techniques—to using solidification-science-based approaches to tailor advanced materials for application-specific needs. The current and emerging applications of cast MMCs in a variety of automotive, aerospace, electronic packaging, and consumer-good industries exemplify the maturity of the field and the materials. Innovations in composite-forming techniques and efforts at wider industrial acceptance of MMCs will undoubtedly continue. However, the scientific principles underlying the solidification microstructure evolution that governs the composite properties have become well established, to a great extent, due to Flemings’ early, pioneering work on monolithic alloys and some of his more recent studies on solidification of reinforced metals. This paper reviews some aspects of solidification of discontinuously reinforced cast metals that owe their current understanding to Flemings’ contributions, in particular, the scientific understanding of macro- and microsegregation, fluidity and rheology of multiphase slurries, and stircasting, semi-solid casting, and preform infiltration. Current research to develop and test prototype components made from cast composites, including Al-flyash, Cu-graphite, Al-graphite, Al-alumina, and SiC-Al, is also presented, along with directions for future research.

  19. Windward Cooling: An Overlooked Factor in the Calculation of Wind Chill.

    NASA Astrophysics Data System (ADS)

    Osczevski, Randall J.

    2000-12-01

    Wind chill equivalent temperatures calculated from a recent vertical cylinder model of wind chill are several degrees colder than those calculated from a facial cooling model. The latter was based on experiments with a heated model of a face in a wind tunnel. Wind chill has sometimes been modeled as the overall heat transfer from the surface of a cylinder in cross flow, but such models average the cooling over the whole surface and thus minimize the effect of local cooling on the upwind side, particularly at low wind speeds. In this paper, a vertical cylinder model of wind chill has been modified so that just the cooling of its windward side is considered. Wind chill equivalent temperatures calculated with this new model compare favorably with those calculated by the facial cooling model.

  20. Stratified storage economically increases capacity and efficiency of campus chilled water system

    SciTech Connect

    Bahnfleth, W.P.; Joyce, W.S.

    1995-03-01

    This article describes how the addition of stratified chilled water storage to the Cornell University campus chilled water system has increased its capacity and efficiency and reduced its operating costs for less than the cost of a conventional chilled water plant expansion. While chilled water storage is not appropriate for all chilled water systems, the experience at Cornell indicates that it can be very cost effective when favorable conditions exist. It should receive serious consideration by owners of large systems who are investigating alternatives for system expansion. The benefits of variable speed chiller operation were found to be considerable. It is hoped that this successful application will stimulate further interest in the development and application of variable speed drive chillers.

  1. Chemical additive to enhance antimicrobial efficacy of chlorine and control cross-contamination during immersion chill of broiler carcasses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Immersion chilling during broiler processing can be a site for cross contamination between the occasional highly contaminated carcass and those that are co-chilled. Chlorine is often used as a chill tank antimicrobial but it can be overcome with heavy organic loads associated with the constant supp...

  2. Nondestructive detection of chilling injury in cucumber fruit using hyperspectral imaging with feature selection and supervised classification

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chilling injury, as a physiological disorder in cucumbers, occurs after the fruit has been subjected to low temperatures. It is thus desirable to detect chilling injury at early stages and/or remove chilling injured cucumbers during sorting and grading. This research was aimed to apply hyperspectral...

  3. [Effects of chilling stress on antioxidant system and ultrastructure of walnut cultivars].

    PubMed

    Tian, Jing-hua; Wang, Hong-xia; Zhang, Zhi-hua; Gao, Yi

    2015-05-01

    In order to reveal cold hardiness mechanisms and ascertain suitable cold hardiness biochemical indicators of walnut (Juglans regia) , three walnut cultivars ' Hartley' , 'Jinlong 1' and 'Jinlong 2' with strong to weak tolerance of chilling stress, were used to investigate variations of leaf antioxidant enzyme activity and superoxide anion (O2-·) content in one year-old branches under chilling stress at 1 °C in leaf-expansion period. The mesophyll cells ultrastructure of ' Hartley' and 'Jinlong 2' under chilling stress were also observed by transmission electron microscope. The results showed that the superoxide dismutase (SOD) and peroxidase (POD) enzyme activities were the strongest and O2-· content was the lowest in chilling-tolerant cultivar ' Hartley' under chilling stress among the three cultivars. The ultrastructure of the mesophyll cells was stable, and chilling injury symptoms of the leaves were not observed. In chilling-sensitive cultivar 'Jinlong 2' , the SOD, POD and catalase enzyme ( CAT) activities decreased sharply, and the O2-· content was kept at a high level under chilling stress. The ultrastructure of the mesophyll cells was injured obviously at 1 °C∟ for 72 hours. Most of chloroplasts were swollen, and grana lamella became thinner and fewer. A number of chloroplasts envelope and plasma membrane were damaged and became indistinct. At the same time, the edges of some of 'Jinlong 2' young leaves became water-soaked. It was concluded that the ultrastructure stability of mesophyll cells under chilling stress was closely related to walnut cold hardiness. SOD, POD enzyme activities and O2-· content in walnut leaves could be used as biochemical indicators of walnut cold hardiness in leaf-expansion period. There might be a correlation between the damage of cell membrane system and reactive oxygen accumulation under chilling stress.

  4. Climate Change Affects Winter Chill for Temperate Fruit and Nut Trees

    PubMed Central

    Luedeling, Eike; Girvetz, Evan H.; Semenov, Mikhail A.; Brown, Patrick H.

    2011-01-01

    Background Temperate fruit and nut trees require adequate winter chill to produce economically viable yields. Global warming has the potential to reduce available winter chill and greatly impact crop yields. Methodology/Principal Findings We estimated winter chill for two past (1975 and 2000) and 18 future scenarios (mid and end 21st century; 3 Global Climate Models [GCMs]; 3 greenhouse gas emissions [GHG] scenarios). For 4,293 weather stations around the world and GCM projections, Safe Winter Chill (SWC), the amount of winter chill that is exceeded in 90% of all years, was estimated for all scenarios using the “Dynamic Model” and interpolated globally. We found that SWC ranged between 0 and about 170 Chill Portions (CP) for all climate scenarios, but that the global distribution varied across scenarios. Warm regions are likely to experience severe reductions in available winter chill, potentially threatening production there. In contrast, SWC in most temperate growing regions is likely to remain relatively unchanged, and cold regions may even see an increase in SWC. Climate change impacts on SWC differed quantitatively among GCMs and GHG scenarios, with the highest GHG leading to losses up to 40 CP in warm regions, compared to 20 CP for the lowest GHG. Conclusions/Significance The extent of projected changes in winter chill in many major growing regions of fruits and nuts indicates that growers of these commodities will likely experience problems in the future. Mitigation of climate change through reductions in greenhouse gas emissions can help reduce the impacts, however, adaption to changes will have to occur. To better prepare for likely impacts of climate change, efforts should be undertaken to breed tree cultivars for lower chilling requirements, to develop tools to cope with insufficient winter chill, and to better understand the temperature responses of tree crops. PMID:21629649

  5. Effects of Aesthetic Chills on a Cardiac Signature of Emotionality

    PubMed Central

    Sumpf, Maria; Jentschke, Sebastian; Koelsch, Stefan

    2015-01-01

    Background Previous studies have shown that a cardiac signature of emotionality (referred to as EK, which can be computed from the standard 12 lead electrocardiogram, ECG), predicts inter-individual differences in the tendency to experience and express positive emotion. Here, we investigated whether EK values can be transiently modulated during stimulation with participant-selected music pieces and film scenes that elicit strongly positive emotion. Methodology/Principal Findings The phenomenon of aesthetic chills, as indicated by measurable piloerection on the forearm, was used to accurately locate moments of peak emotional responses during stimulation. From 58 healthy participants, continuous EK values, heart rate, and respiratory frequency were recorded during stimulation with film scenes and music pieces, and were related to the aesthetic chills. EK values, as well as heart rate, increased significantly during moments of peak positive emotion accompanied by piloerection. Conclusions/Significance These results are the first to provide evidence for an influence of momentary psychological state on a cardiac signature of emotional personality (as reflected in EK values). The possibility to modulate ECG amplitude signatures via stimulation with emotionally significant music pieces and film scenes opens up new perspectives for the use of emotional peak experiences in the therapy of disorders characterized by flattened emotionality, such as depression or schizoid personality disorder. PMID:26083383

  6. When Your Child Needs a Cast

    MedlinePlus

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

  7. Apollo 14 composite casting demonstration

    NASA Technical Reports Server (NTRS)

    1971-01-01

    This program assisted in the design and implementation of the composite casting demonstration for the Apollo 14 mission. Both flight and control samples were evaluated. Some conclusions resulting from a comparison of the flight and control samples were: (1) Solidification in neither the flight nor control samples was truly directional. (2) Apparent intermittent contact of the melt with the container in the flight samples led to unusual nucleation and growth structures. (3) There was greater uniformity, on a macro scale, of both pores and structural features in the flight sample; presumably the result of the reduced gravity conditions. (4) It seems quite feasible to produce enhanced dispersions of gases and dense phases in a melt which is solidified in reduced gravity. (5) A two-stage heating/cooling cycle may help directional solidification. (6) Sample materials should be selected from materials in which the dispersant fully wets the matrix material. (7) Experiments should be conducted in two modes: (1) where the melt is in good thermal contact with the container, and (2) where the melt is in a free-float condition.

  8. Prototype casting fabrication by stereolithography

    SciTech Connect

    Cromwell, W.E.

    1992-03-01

    The evolution of the new technology of producing CAD models by ultraviolet solidification of resin materials (``STEREOLITHOGRAPHY``) continues to progress. The potential application area of rigid fabrication of prototype investment castings is becoming more feasible as we continue to successfully yield experimental castings by the ``SHELL`` processing method. This supplemental (to 11/90 publication) report briefly reviews the original project objectives, activities related to these objectives since November 1990, and progress made through December 1991. We discuss several new case studies involving new resin materials (and other materials) tested along with investment casting processing results. The most recent success, the processing of the highly complex ``C`` HOUSING design by the ``shell`` mold process in both aluminum and steel, will be discussed. This is considered a major breakthrough toward establishing this new technology as a viable approach to the rapid development of prototype investment castings, employing the most common aerospace (precision) cast process. Our future planning calls for expanding the study to help the investment casting industry in refining related processing techniques and to continue our evaluation of new resins suitable for the casting process. Present project planning calls for the completion of this study by the third quarter FY93 or sooner. We believe that with the continued excellent cooperation of our casting supplier study team and an accelerated effort by resin materials producers to further refine related materials, we can achieve all objectives during the planned time frame.

  9. Prototype casting fabrication by stereolithography

    SciTech Connect

    Cromwell, W.E.

    1992-03-01

    The evolution of the new technology of producing CAD models by ultraviolet solidification of resin materials ( STEREOLITHOGRAPHY'') continues to progress. The potential application area of rigid fabrication of prototype investment castings is becoming more feasible as we continue to successfully yield experimental castings by the SHELL'' processing method. This supplemental (to 11/90 publication) report briefly reviews the original project objectives, activities related to these objectives since November 1990, and progress made through December 1991. We discuss several new case studies involving new resin materials (and other materials) tested along with investment casting processing results. The most recent success, the processing of the highly complex C'' HOUSING design by the shell'' mold process in both aluminum and steel, will be discussed. This is considered a major breakthrough toward establishing this new technology as a viable approach to the rapid development of prototype investment castings, employing the most common aerospace (precision) cast process. Our future planning calls for expanding the study to help the investment casting industry in refining related processing techniques and to continue our evaluation of new resins suitable for the casting process. Present project planning calls for the completion of this study by the third quarter FY93 or sooner. We believe that with the continued excellent cooperation of our casting supplier study team and an accelerated effort by resin materials producers to further refine related materials, we can achieve all objectives during the planned time frame.

  10. Lost-Soap Aluminum Casting.

    ERIC Educational Resources Information Center

    Mihalow, Paula

    1980-01-01

    Lost-wax casting in sterling silver is a costly experience for the average high school student. However, this jewelry process can be learned at no cost if scrap aluminum is used instead of silver, and soap bars are used instead of wax. This lost-soap aluminum casting process is described. (Author/KC)

  11. Education and Caste in India

    ERIC Educational Resources Information Center

    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…

  12. The Influence of Cast Shadows on the Detection of Three-Dimensional Curved Contour Structure.

    PubMed

    Khuu, Sieu K; Honson, Vanessa J; Challinor, Kirsten L

    2016-04-01

    Cast shadows have been shown to provide an effective ordinal cue to the depth position of objects. In the present study, two experiments investigated the effectiveness of cast shadows in facilitating the detection of spatial contours embedded in a field of randomly placed elements. In Experiment 1, the separation between the cast shadow and the contour was systematically increased to effectively signal different contour depth positions (relative to background elements), and this was repeated for patterns in which the lighting direction was above and from below. Increasing the shadow separation improved contour detection performance, but the degree to which sensitivity changed was dependent on the lighting direction. Patterns in which the light was from above were better detected than patterns in which the lighting direction was from below. This finding is consistent with the visual system assuming a "light-from-above rule" when processing cast shadows. In Experiment 2, we examined the degree to which changing the shape of the cast shadow (by randomly jittering the position of local cast shadow elements) affected the ability of the visual system to rely on the cast shadow to cue the depth position of the contour. Consistent with a coarse scale analysis, we find that cast shadows remained an effective depth cue even at large degrees of element jitter. Our findings demonstrate that cast shadows provide an effective means of signaling depth, which aids the process of contour integration, and this process is largely tolerant of local variations in lighting direction.

  13. The Influence of Cast Shadows on the Detection of Three-Dimensional Curved Contour Structure.

    PubMed

    Khuu, Sieu K; Honson, Vanessa J; Challinor, Kirsten L

    2016-04-01

    Cast shadows have been shown to provide an effective ordinal cue to the depth position of objects. In the present study, two experiments investigated the effectiveness of cast shadows in facilitating the detection of spatial contours embedded in a field of randomly placed elements. In Experiment 1, the separation between the cast shadow and the contour was systematically increased to effectively signal different contour depth positions (relative to background elements), and this was repeated for patterns in which the lighting direction was above and from below. Increasing the shadow separation improved contour detection performance, but the degree to which sensitivity changed was dependent on the lighting direction. Patterns in which the light was from above were better detected than patterns in which the lighting direction was from below. This finding is consistent with the visual system assuming a "light-from-above rule" when processing cast shadows. In Experiment 2, we examined the degree to which changing the shape of the cast shadow (by randomly jittering the position of local cast shadow elements) affected the ability of the visual system to rely on the cast shadow to cue the depth position of the contour. Consistent with a coarse scale analysis, we find that cast shadows remained an effective depth cue even at large degrees of element jitter. Our findings demonstrate that cast shadows provide an effective means of signaling depth, which aids the process of contour integration, and this process is largely tolerant of local variations in lighting direction. PMID:27107019

  14. A chilling sensitive mutant of Arabidopsis with altered steryl-ester metabolism

    SciTech Connect

    Hugly, S.; McCourt, P.; Somerville, C. ); Browse, J. ); Patterson, G.W. )

    1990-07-01

    A chilling-sensitive mutant of Arabidopsis thaliana was isolated and subjected to genetic, physiological, and biochemical analysis. The chilling-sensitive nature of the mutant line is due to a single recessive nuclear mutation at a locus designated chs1. In contrast to wild-type plants, which are not adversely affected by low temperatures, the chs1 mutant is killed by several days of exposure to temperatures below 18{degree}C. Following exposure to chilling temperatures, the mutant displays two common symptoms of chilling injury - leaf chlorosis and electrolyte leakage. In these respects, the physiological response of the mutant to low temperatures mimics the response observed in some naturally occurring chilling sensitive species. The biochemical basis of chilling sensitivity was explored by examining the pattern of incorporation of {sup 14}CO{sub 2} into soluble metabolites and lipids in wild-type and mutant plants. The only difference observed between the mutant and wild type was that following low temperature treatment, the mutant accumulated 10-fold more radioactivity in a specific class of neutral lipids which were identified by a variety of criteria to be steryl-esters. The accumulation of radioactivity in the steryl-ester fraction occurs 24 hours before there is any visible evidence of chilling injury.

  15. Music chills: The eye pupil as a mirror to music's soul.

    PubMed

    Laeng, Bruno; Eidet, Lise Mette; Sulutvedt, Unni; Panksepp, Jaak

    2016-08-01

    This study evaluated whether music-induced aesthetic "chill" responses, which typically correspond to peak emotional experiences, can be objectively monitored by degree of pupillary dilation. Participants listened to self-chosen songs versus control songs chosen by other participants. The experiment included an active condition where participants made key presses to indicate when experiencing chills and a passive condition (without key presses). Chills were reported more frequently for self-selected songs than control songs. Pupil diameter was concurrently measured by an eye-tracker while participants listened to each of the songs. Pupil size was larger within specific time-windows around the chill events, as monitored by key responses, than in comparison to pupil size observed during 'passive' song listening. In addition, there was a clear relationship between pupil diameter within the chills-related time-windows during both active and passive conditions, thus ruling out the possibility that chills-related pupil dilations were an artifact of making a manual response. These findings strongly suggest that music chills can be visible in the moment-to-moment changes in the size of pupillary responses and that a neuromodulatory role of the central norepinephrine system is thereby implicated in this phenomenon. PMID:27500655

  16. Music chills: The eye pupil as a mirror to music's soul.

    PubMed

    Laeng, Bruno; Eidet, Lise Mette; Sulutvedt, Unni; Panksepp, Jaak

    2016-08-01

    This study evaluated whether music-induced aesthetic "chill" responses, which typically correspond to peak emotional experiences, can be objectively monitored by degree of pupillary dilation. Participants listened to self-chosen songs versus control songs chosen by other participants. The experiment included an active condition where participants made key presses to indicate when experiencing chills and a passive condition (without key presses). Chills were reported more frequently for self-selected songs than control songs. Pupil diameter was concurrently measured by an eye-tracker while participants listened to each of the songs. Pupil size was larger within specific time-windows around the chill events, as monitored by key responses, than in comparison to pupil size observed during 'passive' song listening. In addition, there was a clear relationship between pupil diameter within the chills-related time-windows during both active and passive conditions, thus ruling out the possibility that chills-related pupil dilations were an artifact of making a manual response. These findings strongly suggest that music chills can be visible in the moment-to-moment changes in the size of pupillary responses and that a neuromodulatory role of the central norepinephrine system is thereby implicated in this phenomenon.

  17. Development of hyperspectral imaging technique for the detection of chilling injury in cucumbers

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Chen, Yud-Ren; Wang, C. Y.; Chan, D. E.; Kim, Moon S.

    2004-11-01

    Hyperspectral images of cucumbers were acquired before and during cold storage treatments as well as during subsequent room temperature (RT) storage to explore the potential for the detection of chilling induced damage in whole cucumbers. Region of interest (ROI) spectral features of chilling injured areas, resulting from cold storage treatments at 0°C or 5°C, showed a reduction in reflectance intensity during multi-day post chilling periods of RT storage. Large spectral differences between good-smooth skins and chilling injured skins occurred in the 700-850 nm visible/NIR region. A number of data processing methods, including simple spectral band algorithms, second difference, and principal component analysis (PCA), were attempted to discriminate the ROI spectra of good cucumber skins from those of chilling injured skins. Results revealed that using either a dual-band ratio algorithm (Q811/756) or a PCA model from a narrow spectral region of 733-848 nm could detect chilling injured skins with a success rate of over 90%. Furthermore, the dual-band algorithm was applied to the analysis of images of cucumbers at different conditions, and the resultant images showed more correct identification of chilling injured spots than other processing methods.

  18. The mechanism by which NaCl treatment alleviates PSI photoinhibition under chilling-light treatment.

    PubMed

    Yang, Cheng; Zhang, Zi-shan; Gao, Hui-yuan; Fan, Xing-li; Liu, Mei-jun; Li, Xiang-dong

    2014-11-01

    The effects of chilling-light stress combined with additional stress on PSI and PSII photoinhibition and their interrelationship have not been known. To explore whether NaCl affects the PSI and PSII photoinhibition and their interrelationship under chilling-light treatment, the PSI and PSII activities were studied under chilling-light with or without NaCl treatment. The results showed that the extent of PSI and PSII photoinhibition both increased under chilling-light, while NaCl aggravated PSII photoinhibition and severely damaged cytochrome b₆/f complex but alleviated PSI photoinhibition. Moreover, DCMU had a similar effect as NaCl in this study, which indicates that NaCl alleviated PSI photoinhibition through reducing electrons transported to PSI. It was also showed that the increased damage to PSII by NaCl did not depend on the inhibition of PSII repair and PSI electron transportation. In conclusion, NaCl alleviated PSI photoinhibition by inhibiting electron transport from PSII under chilling-light conditions. In addition, PSII photoinhibition was not affected by PSI photoinhibition because of a full inhibition of PSII repair by chilling-light treatment. We also speculate that NaCl aggravates PSII photoinhibition by enhancing the damage instead of inhibiting the repair of it under chilling-light conditions.

  19. The effect of evaporative air chilling and storage temperature on quality and shelf life of fresh chicken carcasses.

    PubMed

    Mielnik, M B; Dainty, R H; Lundby, F; Mielnik, J

    1999-07-01

    The effect of evaporative air chilling on quality of fresh chicken carcasses was compared with air chilling as reference method. Cooling efficiency and total heat loss were significantly higher for evaporative air chilling. The chilling method was of great importance for weight loss. Chicken chilled in cold air lost considerably more weight than chicken cooled by evaporative air chilling; the difference was 1.8%. The chilling method also affected the skin color and the amount of moisture on skin surface. After evaporative air chilling, the chicken carcasses had a lighter color and more water on the back and under the wings. The moisture content in skin and meat, cooking loss, and pH were not affected by chilling method. Odor attributes of raw chicken and odor and flavor attributes of cooked chicken did not show any significant differences between the two chilling methods. The shelf life of chicken stored at 4 and -1 C were not affected significantly by chilling method. Storage time and temperature appeared to be the decisive factors for sensory and microbiological quality of fresh chicken carcasses.

  20. Physiological and Biochemical Mechanisms of Seed Priming-Induced Chilling Tolerance in Rice Cultivars

    PubMed Central

    Hussain, Saddam; Khan, Fahad; Hussain, Hafiz A.; Nie, Lixiao

    2016-01-01

    Rice belongs to tropical and subtropical environments and is extremely sensitive to chilling stress particularly during emergence and early stages of seedling development. Seed priming can be a good approach to enhance rice germination and stand establishment under chilling stress. The present study examined the role of different seed priming techniques viz., hydropriming, osmopriming, redox priming, chemical priming, and hormonal priming, in enhancing the chilling tolerance in rice. The most effective reagents and their pre-optimized concentrations based on preliminary experiments were used in this study. Two different rice cultivars were sown under chilling stress (18°C) and normal temperatures (28°C) in separate growth chambers. A non-primed control treatment was also maintained for comparison. Chilling stress caused erratic and delayed germination, poor seedling growth, reduced starch metabolism, and lower respiration rate, while higher lipid peroxidation and hydrogen peroxide accumulation in rice seedlings of both cultivars. Nevertheless, all the seed priming treatments effectively alleviated the negative effects of chilling stress. In addition, seed priming treatments triggered the activities of superoxide dismutase, peroxidase, and catalase, and enhanced the accumulations of glutathione and free proline in rice seedlings, which suggests that these measures help prevent the rice seedlings from chilling induced oxidative stress. Chemical priming with selenium and hormonal priming with salicylic acid remained more effective treatments for both rice cultivars under chilling stress than all other priming treatments. The better performance and greater tolerance of primed rice seedlings was associated with enhanced starch metabolism, high respiration rate, lower lipid peroxidation, and strong antioxidative defense system under chilling stress. PMID:26904078

  1. Physiological and Biochemical Mechanisms of Seed Priming-Induced Chilling Tolerance in Rice Cultivars.

    PubMed

    Hussain, Saddam; Khan, Fahad; Hussain, Hafiz A; Nie, Lixiao

    2016-01-01

    Rice belongs to tropical and subtropical environments and is extremely sensitive to chilling stress particularly during emergence and early stages of seedling development. Seed priming can be a good approach to enhance rice germination and stand establishment under chilling stress. The present study examined the role of different seed priming techniques viz., hydropriming, osmopriming, redox priming, chemical priming, and hormonal priming, in enhancing the chilling tolerance in rice. The most effective reagents and their pre-optimized concentrations based on preliminary experiments were used in this study. Two different rice cultivars were sown under chilling stress (18°C) and normal temperatures (28°C) in separate growth chambers. A non-primed control treatment was also maintained for comparison. Chilling stress caused erratic and delayed germination, poor seedling growth, reduced starch metabolism, and lower respiration rate, while higher lipid peroxidation and hydrogen peroxide accumulation in rice seedlings of both cultivars. Nevertheless, all the seed priming treatments effectively alleviated the negative effects of chilling stress. In addition, seed priming treatments triggered the activities of superoxide dismutase, peroxidase, and catalase, and enhanced the accumulations of glutathione and free proline in rice seedlings, which suggests that these measures help prevent the rice seedlings from chilling induced oxidative stress. Chemical priming with selenium and hormonal priming with salicylic acid remained more effective treatments for both rice cultivars under chilling stress than all other priming treatments. The better performance and greater tolerance of primed rice seedlings was associated with enhanced starch metabolism, high respiration rate, lower lipid peroxidation, and strong antioxidative defense system under chilling stress.

  2. Chilling and frost tolerance in Miscanthus and Saccharum genotypes bred for cool temperate climates

    PubMed Central

    Friesen, Patrick C.; Peixoto, Murilo M.; Busch, Florian A.; Johnson, Daniel C.; Sage, Rowan F.

    2014-01-01

    Miscanthus hybrids are leading candidates for bioenergy feedstocks in mid to high latitudes of North America and Eurasia, due to high productivity associated with the C4 photosynthetic pathway and their tolerance of cooler conditions. However, as C4 plants, they may lack tolerance of chilling conditions (0–10 °C) and frost, particularly when compared with candidate C3 crops at high latitudes. In higher latitudes, cold tolerance is particularly important if the feedstock is to utilize fully the long, early-season days of May and June. Here, leaf gas exchange and fluorescence are used to assess chilling tolerance of photosynthesis in five Miscanthus hybrids bred for cold tolerance, a complex Saccharum hybrid (energycane), and an upland sugarcane variety with some chilling tolerance. The chilling treatment consisted of transferring warm-grown plants (25/20 °C day/night growth temperatures) to chilling (12/5 °C) conditions for 1 week, followed by assessing recovery after return to warm temperatures. Chilling tolerance was also evaluated in outdoor, spring-grown Miscanthus genotypes before and after a cold front that was punctuated by a frost event. Miscanthus×giganteus was found to be the most chilling-tolerant genotype based on its ability to maintain a high net CO2 assimilation rate (A) during chilling, and recover A to a greater degree following a return to warm conditions. This was associated with increasing its capacity for short-term dark-reversible photoprotective processes (ΦREG) and the proportion of open photosystem II reaction centres (qL) while minimizing photoinactivation (ΦNF). Similarly, in the field, M.×giganteus exhibited a significantly greater A and pre-dawn F v/F m after the cold front compared with the other chilling-sensitive Miscanthus hybrids. PMID:24642848

  3. Monitoring and analysis of a chill storage system

    NASA Astrophysics Data System (ADS)

    Schaetzle, W. J.; Brett, C. E.

    1982-12-01

    Parisian, a major department store in University Mall, Tuscaloosa, Alabama, has a free cooling system installed to provide air conditioning. The system uses a cooling tower during cold weather, below 47 F Wet bulb temperature, to chill water to an average 43 F. The cold water is stored in an unconfined aquifer and recovered as required for air conditioning on an annual basis. This contract provides monitoring of this system to evaluate system performance. Instrumentation for monitoring has been selected and is being installed. Water temperatures and integrated flow entering and leaving the air conditioning cooling coils and the cooling tower are the prime measurements. Power input to all pumps and cooling tower is also measured. In addition, the temperatures leaving and entering the wells and near the bottom of the wells are measured at random intervals. The water levels in the wells are measured at similar times. Store and ambient data are also recorded.

  4. Quality and bacteriological consequences of beef carcass spray-chilling: Effects of spray duration and boxed beef storage temperature.

    PubMed

    Greer, G G; Jones, S D

    1997-01-01

    The effects of water spray-chilling on beef carcass traits and muscle quality, bacteriology and retail case life were determined in a research abattoir. Chilling treatments were compared using 10 crossbred steer carcasses (280 ± 4 kg) at each spray duration (4, 8, 12 and 16 h) and each vacuum storage temperature (1, 4, 8 and 12 °C). Control sides were air-chilled (1 °C, 24 h) while spray-chilled sides were sprayed with an intermittent water mist at 1 °C in four, 60 s cycles/h for the initial 4-16 h of chilling. The effects of storage temperature were evaluated using vacuum packaged longissimus thoracis (LT) muscle at post-chill intervals of 2, 16, 30 and 44 days. Chilling treatment effects were similar at all spray-chill durations and LT vacuum storage times and temperatures. Carcass spray-chilling did not effect pH, lean colour, % moisture, sarcomere length, shear value or weight loss during the vacuum storage of LT muscle. Carcass fat colour tended to brighten as spray duration was extended up to 12 h, but there was a grey discoloration of fat at spray durations beyond 12 h. Chilling treatment had only marginal effects on anaerobic bacteria during the vacuum storage of LT muscles, or aerobic bacteria during the retail display of rib-eye steaks, and the retail case life of steaks was largely unaffected by spray-chilling. A linear relationship between spray-chill duration and carcass weight loss was determined and carcass shrinkage was reduced by 0.08 g/100 g for every hour of spray-chilling. It was estimated that a major beef processing abattoir could utilize spray-chilling to save more than 2000 kg daily in carcass shrinkage, without compromising quality or increasing spoilage losses.

  5. Sixty Years of Casting Research

    NASA Astrophysics Data System (ADS)

    Campbell, John

    2015-11-01

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

  6. The CSU-CHILL REU: The Interdisciplinary challenge

    NASA Astrophysics Data System (ADS)

    Chandra, C. V.; Hardin, J. C.

    2014-12-01

    The CSU-CHILL Research Experience for Undergraduates program at Colorado State University has been around for a while, operating under the fundamental goal of providing Research Experiences in Atmospheric Technology and Science. During that period, while the science challenges have evolved, the technological advancements have been moving at breakneck speed. Therefore we have the constant challenge of providing cutting edge research experiences to undergraduate students, where the students may not have had exposure beyond their own discipline. The CSU-CHILL REU provides students experience in current research topics. Students publish in leading conferences every year, and produce high quality research. This paper will provide examples of how the interface between technology and science has evolved over years, where some cross training has become easy, while some other challenges still remain. This REU focuses on small groups, so that we can establish one-on-one connections between mentors and students, and instead of just involving students in cutting edge research, we have them actively create it. Students are not merely assigned a small part of a larger project, but often lead their own project. We consider mentors to be supporting their student's research, and not the other way around. This has led to some very interesting research projects that have contributed to science, and to society at large. In this presentation we will discuss some of the specific challenges that we have encountered when running an interdisciplinary REU program, as well as some of the secondary support activities that we do that extend far beyond the student's participation in the REU.

  7. Salicylate Accumulation Inhibits Growth at Chilling Temperature in Arabidopsis1

    PubMed Central

    Scott, Ian M.; Clarke, Shannon M.; Wood, Jacqueline E.; Mur, Luis A.J.

    2004-01-01

    The growth of Arabidopsis plants in chilling conditions could be related to their levels of salicylic acid (SA). Plants with the SA hydroxylase NahG transgene grew at similar rates to Col-0 wild types at 23°C, and growth of both genotypes was slowed by transfer to 5°C. However, at 5°C, NahG plants displayed relative growth rates about one-third greater than Col-0, so that by 2 months NahG plants were typically 2.7-fold larger. This resulted primarily from greater cell expansion in NahG rosette leaves. Specific leaf areas and leaf area ratios remained similar in both genotypes. Net assimilation rates were similar in both genotypes at 23°C, but higher in NahG at 5°C. Chlorophyll fluorescence measurements revealed no PSII photodamage in chilled leaves of either genotype. Col-0 shoots at 5°C accumulated SA, particularly in glucosylated form. SA in NahG shoots showed similar tendencies at 5°C, but at greatly depleted levels. Catechol was not detected as a metabolite of the NahG transgene product. We also examined growth and SA levels in SA signaling and metabolism mutants at 5°C. The partially SA-insensitive npr1 mutant displayed growth intermediate between NahG and Col-0, while the SA-deficient eds5 mutant behaved like NahG. In contrast, the cpr1 mutant at 5°C accumulated very high levels of SA and its growth was much more inhibited than wild type. At both temperatures, cpr1 was the only SA-responsive genotype in which oxidative damage (measured as thiobarbituric acid-reactive substances) was significantly different from wild type. PMID:15173571

  8. Biomimetic Materials by Freeze Casting

    NASA Astrophysics Data System (ADS)

    Porter, Michael M.; Mckittrick, Joanna; Meyers, Marc A.

    2013-06-01

    Natural materials, such as bone and abalone nacre, exhibit exceptional mechanical properties, a product of their intricate microstructural organization. Freeze casting is a relatively simple, inexpensive, and adaptable materials processing method to form porous ceramic scaffolds with controllable microstructural features. After infiltration of a second polymeric phase, hybrid ceramic-polymer composites can be fabricated that closely resemble the architecture and mechanical performance of natural bone and nacre. Inspired by the narwhal tusk, magnetic fields applied during freeze casting can be used to further control architectural alignment, resulting in freeze-cast materials with enhanced mechanical properties.

  9. Pressure Rig for Repetitive Casting

    NASA Technical Reports Server (NTRS)

    Vasquez, P.; Hutto, W. R.

    1986-01-01

    Equipment life increased by improved insulation. New design cuts time of preparation for casting from several days to about 1 hour. Savings due to elimination of lengthy heating and drying operations associated with preparation of ceramic mold. Quality of casting improved because moisture in cavity eliminated by use of insulating material, and more uniform pressure applied to process. Commercial blanket insulator protects components from heat, increasing life of pressure rig and enabling repeated use. Improved heat protection allows casting of brass and other alloys with higher melting temperatures in pressure rig.

  10. Automated multiple view inspection of metal castings

    NASA Astrophysics Data System (ADS)

    Mery, Domingo; Carrasco, Miguel

    2007-01-01

    Automated visual inspection of metal castings is defined as a quality control task that determines automatically if a casting deviates from a given set of specifications using visual data. Many research directions in this field have been exploited, some very different principles have been adopted and a wide variety of algorithms have been appeared in the literature. However, the developed approaches are tailored to the inspection task, i.e., there is no common approach applicable to all cases because the development is an ad hoc process. Additionally, detection accuracy should be improved, because there is a fundamental trade off between false alarms and miss detections. For these reasons, we proposed a novel methodology, called Automated Multiple View Inspection, that uses redundant views of the test object to perform the inspection task. The method is opening up new possibilities in inspection field by taking into account the useful information about the correspondence between the different views. It is very robust because in first step it identifies potential defects in each view and in second step it finds correspondences between potential defects, and only those that are matched in different views are detected as real defects. In this paper, we review the advances done in this field giving an overview of the multiple view inspection and showing experimental results obtained on metal castings.

  11. [Comparison of texture distribution of cold rolled DC and CC AA 5052 aluminum alloy at different positions through thickness direction by XRD].

    PubMed

    Chen, Ming-biao; Ma, Min; Yang, Qing-xiang; Wang, Shan; Liu, Wen-chang; Zhao, Ying-mei

    2013-09-01

    To provide gist of DC AA 5052 and CC AA 5052 aluminum alloy to industry production and application, the texture variation of cold rolled sheets through thickness direction was studied by X-ray diffraction method, and the difference in texture at surface, quarter and center layer was analyzed. The hot plates of direct chill cast (DC) AA 5052 and continuous cast (CC) AA 5052 aluminum alloy were annealed at 454 degrees C for 4 hours and then cold rolled to different reductions. The strength and volume fraction of the fiber in CC AA 5052 aluminum alloy is larger than in DC AA 5052 aluminum alloy after same rolling reduction The volume fraction of the recrystallization texture cube in the CC AA 5052 aluminum alloy is less than in the DC AA 5052 aluminum alloy, which result in that CC AA 5052 aluminum alloy needs less cold rolling reduction than DC AA 5052 aluminum alloy for generating the texture with same intensity and volume fraction at surface layer, quarter layer and center layer. The manufacturability and performance of CC AA 5052 aluminum alloy is superior to DC AA 5052 aluminum alloy for use in stamping.

  12. Infants' discrimination of shapes from shading and cast shadows.

    PubMed

    Sato, Kazuki; Kanazawa, So; Yamaguchi, Masami K

    2016-07-01

    Shadows are powerful cues in the perception of shapes. We can perceive shading and cast shadow implicitly. We investigated infants' ability to detect a single discrepant figure that was depicted by shading or cast shadow and examined the influence of the contrast polarity of shadows on this process. In Experiment 1, we manipulated the blur direction of a shadow to create stimuli that appeared either to be partially shaded or to cast a shadow and then used a preference to test whether this difference would allow 5- to 8-month-old infants to discriminate the figures that adults were able to perceive as different shapes. Only 7- to-8-month-old infants could differentiate one shading figure from cast shadow figures, and vice versa. In Experiment 2, we reversed the contrast polarity of the figure (dark object with a light shadow) and tested whether discrimination was affected. As has been found with adults, infants exposed to this condition were unable to discriminate the contrast-reversed shading and cast shadow figures. Our results suggested that an age of around 7 months is important for development of the ability to perceive shape differences from shading and cast shadows.

  13. Infants' discrimination of shapes from shading and cast shadows.

    PubMed

    Sato, Kazuki; Kanazawa, So; Yamaguchi, Masami K

    2016-07-01

    Shadows are powerful cues in the perception of shapes. We can perceive shading and cast shadow implicitly. We investigated infants' ability to detect a single discrepant figure that was depicted by shading or cast shadow and examined the influence of the contrast polarity of shadows on this process. In Experiment 1, we manipulated the blur direction of a shadow to create stimuli that appeared either to be partially shaded or to cast a shadow and then used a preference to test whether this difference would allow 5- to 8-month-old infants to discriminate the figures that adults were able to perceive as different shapes. Only 7- to-8-month-old infants could differentiate one shading figure from cast shadow figures, and vice versa. In Experiment 2, we reversed the contrast polarity of the figure (dark object with a light shadow) and tested whether discrimination was affected. As has been found with adults, infants exposed to this condition were unable to discriminate the contrast-reversed shading and cast shadow figures. Our results suggested that an age of around 7 months is important for development of the ability to perceive shape differences from shading and cast shadows. PMID:27150615

  14. 21 CFR 888.5940 - Cast component.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Cast component. 888.5940 Section 888.5940 Food and... ORTHOPEDIC DEVICES Surgical Devices § 888.5940 Cast component. (a) Identification. A cast component is a device intended for medical purposes to protect or support a cast. This generic type of device...

  15. 21 CFR 880.6185 - Cast cover.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Cast cover. 880.6185 Section 880.6185 Food and....6185 Cast cover. (a) Identification. A cast cover is a device intended for medical purposes that is made of waterproof material and placed over a cast to protect it from getting wet during a shower or...

  16. 21 CFR 880.6185 - Cast cover.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Cast cover. 880.6185 Section 880.6185 Food and....6185 Cast cover. (a) Identification. A cast cover is a device intended for medical purposes that is made of waterproof material and placed over a cast to protect it from getting wet during a shower or...

  17. 21 CFR 880.6185 - Cast cover.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Cast cover. 880.6185 Section 880.6185 Food and....6185 Cast cover. (a) Identification. A cast cover is a device intended for medical purposes that is made of waterproof material and placed over a cast to protect it from getting wet during a shower or...

  18. 21 CFR 888.5940 - Cast component.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Cast component. 888.5940 Section 888.5940 Food and... ORTHOPEDIC DEVICES Surgical Devices § 888.5940 Cast component. (a) Identification. A cast component is a device intended for medical purposes to protect or support a cast. This generic type of device...

  19. 21 CFR 888.5940 - Cast component.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Cast component. 888.5940 Section 888.5940 Food and... ORTHOPEDIC DEVICES Surgical Devices § 888.5940 Cast component. (a) Identification. A cast component is a device intended for medical purposes to protect or support a cast. This generic type of device...

  20. The Effects of Externally Solidified Product on Wave Celerity and Quality of Die Cast Products

    SciTech Connect

    Carroll Mobley; Yogeshwar Sahai; Jerry Brevick

    2003-10-10

    The cold chamber die casting process is used to produce essentially all the die cast aluminum products and about 50% of the die cast magnesium products made today. Modeling of the cold chamber die casting process and metallographic observations of cold chamber die cast products indicate that typically 5 to 20% of the shot weight is solidified in the shot sleeve before or during cavity filling. The protion of the resulting die casting which is solidified in the shot sleeve is referred to as externally solidified product, or, when identified as a casting defect, as cold flakes. This project was directed to extending the understanding of the effects of externally solidified product on the cold chamber die casting process and products to enable the production of defect-free die castings and reduce the energy associated with these products. The projected energy savings from controlling the fraction of externally solidified product in die cast components is 40 x 10 Btu through the year 2025.

  1. Thermal stratification of chilled-water slot flows into storage tanks

    SciTech Connect

    Stewart, W.E. Jr.; Cai, L.; Sohn, C.W.

    1994-12-31

    A numerical model was used to simulate the two dimensional flow of chilled water into a storage tank initially filled with warm water. The inlet flow is from a small slot in one vertical wall at the bottom of the tank. The numerical model employs a transient stream function-vorticity formulation to predict the streamline and temperature distributions in the tank as a function of time. Turbulence was modeled using the turbulent kinetic energy and turbulent length scale equations. The model results for a side-slot inlet to the tank reveal that the Archimedes number should be greater than 5 and the Reynolds number should be smaller than 1,000 to ensure thermal stratification of the hot and cold water. When stratification is achieved, the temperature distribution varies only in the vertical direction of the tank, where the water temperature is approximately uniform in the horizontal direction. The numerical results are in reasonably good agreement with some experimental data available in the literature.

  2. The Indeterminate Domain Protein ROC1 Regulates Chilling Tolerance via Activation of DREB1B/CBF1 in Rice

    PubMed Central

    Dou, Mingzhu; Cheng, Shuai; Zhao, Baotian; Xuan, Yuanhu; Shao, Minglong

    2016-01-01

    Abiotic stress, including salinity, drought and cold, severely affect diverse aspects of plant development and production. Rice is an important crop that does not acclimate to cold; therefore, it is relatively sensitive to low temperature stress. Dehydration-responsive element-binding protein 1s (DREB1s)/C-repeat binding factors (CBFs) are well known for their function in cold tolerance, but the transcriptional regulation of CBFs remains elusive, especially in rice. Here, we performed a yeast one-hybrid assay using the promoter of CBF1, a cold-induced gene, to isolate transcriptional regulators of CBF1. Among the seven candidates identified, an indeterminate domain (IDD) protein named ROC1 (a regulator of CBF1) was further analyzed. The ROC1 transcript was induced by exogenously-treated auxin, while it was not altered by cold or ABA stimuli. ROC1-GFP was localized at the nucleus, and ROC1 showed trans-activation activity in yeast. The electrophoretic mobility shift assay (EMSA) and ChIP analyses revealed that ROC1 directly bound to the promoter of CBF1. Furthermore, ROC1 mutants exhibited chilling-sensitive symptoms and inhibited cold-mediated induction of CBF1 and CBF3, indicating that ROC1 is a positive regulator of cold stress responses. Taken together, this study identified the CBF1 regulator, and the results are important for rice plant adaptation to chilling stress. PMID:26927068

  3. Investment casting design of experiment. Final report

    SciTech Connect

    Owens, R.

    1997-10-01

    Specific steps in the investment casting process were analyzed in a designed experiment. The casting`s sensitivity to changes in these process steps was experimentally determined Dimensional and radiographic inspection were used to judge the sensitivity of the casting. Thirty-six castings of different pedigrees were poured and measured. Some of the dimensional inspection was conducted during the processing. It was confirmed that wax fixturing, number of gates, gate location, pour and mold temperature, pour speed, and cooling profile all affected the radiographic quality of the casting. Gate and runner assembly techniques, number of gates, and mold temperature affect the dimensional quality of the casting.

  4. Strong and light plaster casts?

    PubMed

    Stewart, Todd; Cheong, Wen; Barr, Victoria; Tang, Daniel

    2009-08-01

    Three geometries of volar slab plaster cast for the stabilisation of wrist fractures were investigated. It was found that by moulding reinforcement ridges on the inferior surface of the slab the strength and stiffness could be doubled with only a 20% increase in weight. It was discovered that to provide the same increase in strength with a traditional cast the entire thickness of the cast would have to be doubled, with a 100% increase in weight that would be cumbersome to most users. Bending theory is presented in a simple manner to allow clinicians to understand how reinforcement mouldings can improve the strength and stiffness of plaster casts without adversely influencing weight, or cost.

  5. Casting Using A Polystyrene Pattern

    NASA Technical Reports Server (NTRS)

    Vasquez, Peter; Guenther, Bengamin; Vranas, Thomas; Veneris, Peter; Joyner, Michael

    1993-01-01

    New technique for making metal aircraft models saves significant amount of time and effort in comparison with conventional lost-wax method. Produces inexpensive, effective wind-tunnel models. Metal wind-tunnel model cast by use of polystyrene pattern.

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

    SciTech Connect

    Song, Hoon; Kim, Jong-Hwan; Kim, Ki-Hwan; Lee, Chan-Bock

    2013-07-01

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

  7. Aesthetic Chills: Knowledge-Acquisition, Meaning-Making, and Aesthetic Emotions.

    PubMed

    Schoeller, Felix; Perlovsky, Leonid

    2016-01-01

    This article addresses the relation between aesthetic emotions, knowledge-acquisition, and meaning-making. We briefly review theoretical foundations and present experimental data related to aesthetic chills. These results suggest that aesthetic chills are inhibited by exposing the subject to an incoherent prime prior to the chill-eliciting stimulation and that a meaningful prime makes the aesthetic experience more pleasurable than a neutral or an incoherent one. Aesthetic chills induced by narrative structures seem to be related to the pinnacle of the story, to have a significant calming effect and subjects describe a strong empathy for the characters. We discuss the relation between meaning-making and aesthetic emotions at the psychological, physiological, narratological, and mathematical levels and propose a series of hypotheses to be tested in future research. PMID:27540366

  8. Aesthetic Chills: Knowledge-Acquisition, Meaning-Making, and Aesthetic Emotions.

    PubMed

    Schoeller, Felix; Perlovsky, Leonid

    2016-01-01

    This article addresses the relation between aesthetic emotions, knowledge-acquisition, and meaning-making. We briefly review theoretical foundations and present experimental data related to aesthetic chills. These results suggest that aesthetic chills are inhibited by exposing the subject to an incoherent prime prior to the chill-eliciting stimulation and that a meaningful prime makes the aesthetic experience more pleasurable than a neutral or an incoherent one. Aesthetic chills induced by narrative structures seem to be related to the pinnacle of the story, to have a significant calming effect and subjects describe a strong empathy for the characters. We discuss the relation between meaning-making and aesthetic emotions at the psychological, physiological, narratological, and mathematical levels and propose a series of hypotheses to be tested in future research.

  9. Aesthetic Chills: Knowledge-Acquisition, Meaning-Making, and Aesthetic Emotions

    PubMed Central

    Schoeller, Felix; Perlovsky, Leonid

    2016-01-01

    This article addresses the relation between aesthetic emotions, knowledge-acquisition, and meaning-making. We briefly review theoretical foundations and present experimental data related to aesthetic chills. These results suggest that aesthetic chills are inhibited by exposing the subject to an incoherent prime prior to the chill-eliciting stimulation and that a meaningful prime makes the aesthetic experience more pleasurable than a neutral or an incoherent one. Aesthetic chills induced by narrative structures seem to be related to the pinnacle of the story, to have a significant calming effect and subjects describe a strong empathy for the characters. We discuss the relation between meaning-making and aesthetic emotions at the psychological, physiological, narratological, and mathematical levels and propose a series of hypotheses to be tested in future research. PMID:27540366

  10. Water Status Related Root-to-Shoot Communication Regulates the Chilling Tolerance of Shoot in Cucumber (Cucumis sativus L.) Plants

    PubMed Central

    Zhang, Zi-Shan; Liu, Mei-Jun; Gao, Hui-Yuan; Jin, Li-Qiao; Li, Yu-Ting; Li, Qing-Ming; Ai, Xi-Zhen

    2015-01-01

    Although root-to-shoot communication has been intensively investigated in plants under drought, few studies have examined root-to-shoot communication under chilling. Here we explored whether root-to-shoot communication contributes to the chilling-light tolerance of cucumber shoots and clarified the key signal involves in this communication. After leaf discs chilling-light treatment, the photoinhibitions of Photosystem I (PSI) and Photosystem II (PSII) were similar in leaf discs of two cucumber varieties (JY-3 and JC-4). When the whole plants, including roots, were chilled under light, the photosynthetic performances in JC-4 leaves decreased more seriously than that in JY-3 leaves. However, when the water status of leaves was maintained by warming roots or floating the attached leaves on water, the PSII activity and amount of PSI in the leaves of the two varieties were similar after chilling-light treatment. In addition, the differences of PSII activities and amount of PSI between the two varieties under whole plant chilling-light treatment were independent of ABA pretreatment. Above results indicate that (1) the better water status in leaves under chilling contributes to the higher chilling tolerance of JY-3; (2) the water status, rather than an ABA signal, dominates root-to-shoot communication under chilling and the chilling tolerance of cucumber shoot. PMID:26471979

  11. Water Status Related Root-to-Shoot Communication Regulates the Chilling Tolerance of Shoot in Cucumber (Cucumis sativus L.) Plants.

    PubMed

    Zhang, Zi-Shan; Liu, Mei-Jun; Gao, Hui-Yuan; Jin, Li-Qiao; Li, Yu-Ting; Li, Qing-Ming; Ai, Xi-Zhen

    2015-10-16

    Although root-to-shoot communication has been intensively investigated in plants under drought, few studies have examined root-to-shoot communication under chilling. Here we explored whether root-to-shoot communication contributes to the chilling-light tolerance of cucumber shoots and clarified the key signal involves in this communication. After leaf discs chilling-light treatment, the photoinhibitions of Photosystem I (PSI) and Photosystem II (PSII) were similar in leaf discs of two cucumber varieties (JY-3 and JC-4). When the whole plants, including roots, were chilled under light, the photosynthetic performances in JC-4 leaves decreased more seriously than that in JY-3 leaves. However, when the water status of leaves was maintained by warming roots or floating the attached leaves on water, the PSII activity and amount of PSI in the leaves of the two varieties were similar after chilling-light treatment. In addition, the differences of PSII activities and amount of PSI between the two varieties under whole plant chilling-light treatment were independent of ABA pretreatment. Above results indicate that (1) the better water status in leaves under chilling contributes to the higher chilling tolerance of JY-3; (2) the water status, rather than an ABA signal, dominates root-to-shoot communication under chilling and the chilling tolerance of cucumber shoot.

  12. Effect of heat shock on the chilling sensitivity of trichomes and petioles of African violet (Saintpaulia ionantha).

    PubMed

    Saltveit, Mikal E.; Hepler, Peter K.

    2004-05-01

    Chilling at 6 degrees C caused an immediate cessation of protoplasmic streaming in trichomes from African violets (Saintpaulia ionantha), and a slower aggregation of chloroplasts in the cells. Streaming slowly recovered upon warming to 20 degrees C, reaching fairly stable rates after 4, 15, 25 and 35 min for tissue chilled for 2 min and for 2, 14 and 24 h, respectively. The rate of ion leakage from excised petioles into an isotonic 0.2 M mannitol solution increased after 12 h of chilling and reached a maximum after 3 days of chilling. A heat shock at 45 degrees C for 6 min reduced chilling-induced rates of ion leakage from excised 1-cm petiole segments by over 50%, namely to levels near that from non-chilled control tissue. Heat-shock treatments themselves had no effect on the rate of ion leakage from non-chilled petiole segments. Protoplasmic streaming was stopped by 1 min of heat shock at 45 degrees C, but slowly recovered to normal levels after about 30 min Chloroplasts aggregation was prevented by a 1 or 2 min 45 degrees C heat-shock treatment administered 1.5 h before chilling, but heat-shock treatments up to 6 min only slightly delayed the reduction in protoplasmic streaming caused by chilling. Tradescantia virginiana did not exhibit symptoms associated with chilling injury in sensitive species (i.e. cessation of protoplasmic streaming in stamen hairs and increased ion leakage from leaf tissue). PMID:15086815

  13. Mapping quantitative trait loci associated with chilling requirement, heat requirement and bloom date in peach (Prunus persica).

    PubMed

    Fan, Shenghua; Bielenberg, Douglas G; Zhebentyayeva, Tetyana N; Reighard, Gregory L; Okie, William R; Holland, Doron; Abbott, Albert G

    2010-03-01

    *Chilling requirement, together with heat requirement, determines the bloom date, which has an impact on the climatic distribution of the genotypes of tree species. The molecular basis of floral bud chilling requirement is poorly understood, despite its importance to the adaptation and production of fruit trees. In addition, the genetic nature of heat requirement and the genetic interrelationships among chilling requirement, heat requirement and bloom date remain unclear. *A peach (Prunus persica) F(2) population of 378 genotypes developed from two genotypes with contrasting chilling requirements was used for linkage map construction and quantitative trait loci (QTL) mapping. The floral bud chilling and heat requirements of each genotype were evaluated over 2 yr and the bloom date was scored over 4 yr. *Twenty QTLs with additive effects were identified for three traits, including one major QTL for chilling requirement and two major QTLs for bloom date. The majority of QTLs colocalized with QTLs for other trait(s). In particular, one genomic region of 2 cM, pleiotropic for the three traits, overlapped with the sequenced peach EVG region. *This first report on the QTL mapping of floral bud chilling requirement will facilitate marker-assisted breeding for low chilling requirement cultivars and the map-based cloning of genes controlling chilling requirement. The extensive colocalization of QTLs suggests that there may be one unified temperature sensing and action system regulating chilling requirement, heat requirement and bloom date together.

  14. Water Status Related Root-to-Shoot Communication Regulates the Chilling Tolerance of Shoot in Cucumber (Cucumis sativus L.) Plants.

    PubMed

    Zhang, Zi-Shan; Liu, Mei-Jun; Gao, Hui-Yuan; Jin, Li-Qiao; Li, Yu-Ting; Li, Qing-Ming; Ai, Xi-Zhen

    2015-01-01

    Although root-to-shoot communication has been intensively investigated in plants under drought, few studies have examined root-to-shoot communication under chilling. Here we explored whether root-to-shoot communication contributes to the chilling-light tolerance of cucumber shoots and clarified the key signal involves in this communication. After leaf discs chilling-light treatment, the photoinhibitions of Photosystem I (PSI) and Photosystem II (PSII) were similar in leaf discs of two cucumber varieties (JY-3 and JC-4). When the whole plants, including roots, were chilled under light, the photosynthetic performances in JC-4 leaves decreased more seriously than that in JY-3 leaves. However, when the water status of leaves was maintained by warming roots or floating the attached leaves on water, the PSII activity and amount of PSI in the leaves of the two varieties were similar after chilling-light treatment. In addition, the differences of PSII activities and amount of PSI between the two varieties under whole plant chilling-light treatment were independent of ABA pretreatment. Above results indicate that (1) the better water status in leaves under chilling contributes to the higher chilling tolerance of JY-3; (2) the water status, rather than an ABA signal, dominates root-to-shoot communication under chilling and the chilling tolerance of cucumber shoot. PMID:26471979

  15. The expression patterns of bromelain and AcCYS1 correlate with blackheart resistance in pineapple fruits submitted to postharvest chilling stress.

    PubMed

    Raimbault, Astrid-Kim; Zuily-Fodil, Yasmine; Soler, Alain; Mora, Phillipe; Cruz de Carvalho, Maria H

    2013-11-01

    Blackheart is a physiological disorder induced by postharvest chilling storage during pineapple fruit export shipping. The aim of this study was to check the involvement of bromelain, the cysteine protease protein family abundantly present in pineapple fruits, and AcCYS1, an endogenous inhibitor of bromelain, in the development of blackheart. For this we checked the response to postharvest chilling treatment of two pineapple varieties (MD2 and Smooth Cayenne) differing in their resistance to blackheart. Quantitative RT-PCR analyses showed that postharvest chilling treatment induced a down-regulation of bromelain transcript accumulation in both varieties with the most dramatic drop in the resistant variety. Regarding AcCYS1 transcript accumulation, the varieties showed opposite trends with an up-regulation in the case of the resistant variety and a down-regulation in the susceptible one. Taken together our results suggest that the control of bromelain and AcCYS1 expression levels directly correlates to the resistance to blackheart development in pineapple fruits. PMID:23777839

  16. The expression patterns of bromelain and AcCYS1 correlate with blackheart resistance in pineapple fruits submitted to postharvest chilling stress.

    PubMed

    Raimbault, Astrid-Kim; Zuily-Fodil, Yasmine; Soler, Alain; Mora, Phillipe; Cruz de Carvalho, Maria H

    2013-11-01

    Blackheart is a physiological disorder induced by postharvest chilling storage during pineapple fruit export shipping. The aim of this study was to check the involvement of bromelain, the cysteine protease protein family abundantly present in pineapple fruits, and AcCYS1, an endogenous inhibitor of bromelain, in the development of blackheart. For this we checked the response to postharvest chilling treatment of two pineapple varieties (MD2 and Smooth Cayenne) differing in their resistance to blackheart. Quantitative RT-PCR analyses showed that postharvest chilling treatment induced a down-regulation of bromelain transcript accumulation in both varieties with the most dramatic drop in the resistant variety. Regarding AcCYS1 transcript accumulation, the varieties showed opposite trends with an up-regulation in the case of the resistant variety and a down-regulation in the susceptible one. Taken together our results suggest that the control of bromelain and AcCYS1 expression levels directly correlates to the resistance to blackheart development in pineapple fruits.

  17. Terral De Vicuna, a Foehnlike Wind in Semiarid Northern Chile: Meteorological Aspects and Implications for the Fulfillment of Chill Requirements in Deciduous Fruit Trees

    NASA Technical Reports Server (NTRS)

    Montes, Carlo; Rutllant, Jose A.; Aguirre, Anita; Bascunan-Godoy, Luisa; Julia, Cristobal

    2016-01-01

    The terral de Vicuña is a warm and dry wind that flows down the Elqui Valley in north-central Chile typically at dawn and early morning. Given that most terral episodes occur in austral winter when chill accumulation by deciduous fruit trees proceeds, negative effects on agriculture may be expected. During 11 (2004-14) winters a meteorological characterization of terral winds and the assessment of their impact on chill accumulation, by the modified Utah Model and the Dynamic Model, were performed. Within this period, 67 terral days (TD) were identified as those in which nighttime to early morning wind direction and speed, air temperature, and relative humidity reached defined thresholds on an hourly basis (terral hours). Most frequent TD featured 6-9 consecutive terral hours; duration is considered here as a proxy for their intensity. Synoptic-scale meteorological analysis shows that 65% of moderate and strong terral events develop as a cold, migratory anticyclone drifts poleward of the study area, coinciding with the onset of a midtropospheric ridge over central Chile, bringing southwest winds on top of the Andes (approximately 500-hPa level). The remaining 35% are either associated with 500-hPa easterlies (foehn like), with prefrontal conditions ahead of a trough driving northwest 500-hPa winds, or with transitional 500-hPa westerlies.Assessments of chill accumulation during TD show that, although present average and cold winter conditions do not represent a major TD hazard to local agriculture, lower chill accumulation associated with anomalously high nocturnal temperatures could be significantly more important during present and future warmer winters.

  18. Endogenous salicylic acid accumulation is required for chilling tolerance in cucumber (Cucumis sativus L.) seedlings.

    PubMed

    Dong, Chun-Juan; Li, Liang; Shang, Qing-Mao; Liu, Xin-Yan; Zhang, Zhi-Gang

    2014-10-01

    Salicylic acid (SA) is an important plant hormone, and its exogenous application can induce tolerance to multiple environmental stresses in plants. In this study, we examine the potential involvement of endogenous SA in response to chilling in cucumber (Cucumis sativus L.) seedlings. A low temperature of 8 °C induces a moderate increase in endogenous SA levels. Chilling stimulates the enzymatic activities and the expression of genes for phenylalanine ammonia-lyase (PAL) and benzoic acid-2-hydroxylase rather than isochorismate synthase. This indicates that the PAL enzymatic pathway contributes to chilling-induced SA production. Cucumber seedlings pretreated with SA biosynthesis inhibitors accumulate less endogenous SA and suffer more from chilling damage. The expression of cold-responsive genes is also repressed by SA inhibitors. The reduction in stress tolerance and in gene expression can be restored by the exogenous application of SA, confirming the critical roles of SA in chilling responses in cucumber seedlings. Furthermore, the inhibition of SA biosynthesis under chilling stress results in a prolonged and enhanced hydrogen peroxide (H2O2) accumulation. The application of exogenous SA and the chemical scavenger of H2O2 reduces the excess H2O2 and alleviates chilling injury. In contrast, the protective effects of SA are negated by foliar spraying with high concentrations of H2O2 and an inhibitor of the antioxidant enzyme. These results suggest that endogenous SA is required in response to chilling stress in cucumber seedlings, by modulating the expression of cold-responsive genes and the precise induction of cellular H2O2 levels.

  19. Optimization protocol for storage of goldfish (Carassius auratus) embryos in chilled state.

    PubMed

    Shaluei, F; Imanpoor, M R; Shabani, A; Nasr-Esfahani, M H

    2014-04-01

    A series of five experiments were conducted to explore suitable conditions for storing of goldfish embryos in a chilled state. The factors studied were embryo stage, storage temperature, physiological saline solutions and goldfish artificial coelomic fluid (GFACF) medium, antibiotics (penicillin and streptomycin), antioxidants (vitamin E, vitamin C), buffer (Hepes, Tris) and BSA (bovine serum albumin). First, goldfish embryos at eight developmental stages were incubated in aerated and dechlorinated tap water at 0 °C for 24 h. Result shows that early developmental stages were most sensitive to chilling. Heartbeat-stage goldfish embryos were chilled at 0, 4 or 8 °C for up to 72 h in water, and chilled storage was possible only for up to 18, 24 and 48 h at 0, 4 and 8 °C, respectively, without a decrease in viability. Chilling of goldfish embryos at 8 °C in GFACF medium and Dettlaff's solution instead of water and other physiological saline solutions prolonged their viability (p < 0.01). Nevertheless, viability of chilled embryos in GFACF medium was slightly, but non-significantly, higher than in Dettlaff's solution. Supplementation of the GFACF medium with antibiotics, Hepes or BSA increased the viability of chilled embryos, but the tested vitamin E analogue Trolox, vitamin C or Tris concentration had no effect on embryo viability. The outcome of this series of experiments shows that heartbeat-stage goldfish embryos could be chilled for 60 h in GFACF supplemented with 25 mm Hepes, 100 U/ml penicillin, 10 μg/l streptomycin and 1 g/l BSA in such a way that embryonic development does not proceed, and viability is not lost.

  20. Alternative schemes for production of chilled water and cogeneration of electricity at Ashley Plant

    SciTech Connect

    Not Available

    1989-01-01

    William Tao Associates, Inc. (TAO) evaluated alternative systems for the generation of Chilled Water at Ashley Plant. The generation of chilled water is necessary for several reason; initially as a source of revenue for St. Louis Thermal Energy Corporation (SLTEC), but more importantly as a necessary component of the Trash-to-Energy Plant proposed north of Ashley Plant. The chilled water system provides a base load for steam generated by the Trash-to-Energy Plant. The benefits include reduced tip-fees to the City of St. Louis, lower cost of energy to customers of both the district steam system and the proposed chilled water system, and will result in lower energy and operating costs for the system than if individual services are provided. This symbiotic relationship is main advantage of the Trash-to-Energy system. TAO provided preliminary engineering of the chilled water line route. The basic assumptions of an initial load of 10,000 tons with an ultimate load of 20,000 tons at a temperature difference of 16{degree}F remain. The findings of the pipeline study, although not incorporated into this document, remain valid. Assumptions include the following: An initial design load of 6000 tons which has the capability of growing to 20,000 tons; Incremental costs of steam generated by Ashley Plant and the Trash-to-Energy plant; The turbine room at Ashley Plant is suitable for gut rehab except for turbines No. 7 and No. 9 which should remain operational; and Daily chilled water flow and annual load profile. The paper describes the findings on 8 alternative chiller systems. Additional studies were performed on the following: chilled water storage; low-pressure absorption chiller for balancing plant steam loads; economizer cycle for chiller system; auxiliary equipment energy source; variable flow water pumps; and comparison to satellite chilled water plant study.

  1. The perception of three-dimensional cast-shadow structure is dependent on visual awareness.

    PubMed

    Khuu, Sieu K; Gordon, Jack; Balcomb, Kaleah; Kim, Juno

    2014-03-19

    In the present study we examined whether the perception of depth from cast shadows is dependent on visual awareness using continuous flash suppression (CFS). As a direct measure of how the visual system infers depth from cast shadows, we examined the cast-shadow motion illusion originally reported by Kersten, Knill, Mamassian, and Bulthoff (1996), in which a moving cast shadow induces illusory motion in depth in a physically stationary object. In Experiment 1, we used a disparity defined probe to determine the stereo motion speed required to match the cast-shadow motion illusion for different cast shadow speeds (0°/s-1.6°/s) and different lighting directions. We found that configurations implying light from above produce more compelling illusory effects. We also found that increasing shadow speed monotonically increased the stereo motion speed required to match the illusory motion, which suggests that quantitative depth can be derived from cast shadows when they are in motion. In Experiment 2, we used CFS to suppress the cast shadow from visual awareness. Visual suppression of the cast shadow from awareness greatly diminished the perception of illusory motion in depth. In Experiment 3 we confirmed that while CFS suppresses the cast-shadow motion from awareness, it continues to be processed by the visual system sufficient to generate a significant motion after effect. The results of the present study suggest that cast shadows can greatly contribute to the perception of scene depth structure, through a process that is dependent on the conscious awareness of the cast shadow.

  2. Influence of chilling and drought on water relations and abscisic acid accumulation in bean

    SciTech Connect

    Vernieri, P.; Pardossi, A.; Tognoni, F. )

    1991-01-01

    Intact bean seedlings were subjected to either chilling (4{degree}C) or drought stress. Leaf water relations and abscisic acid (ABA) content were monitored throughout a stress-recovery cycle. Chilling at low relative humidity (RH) and drought caused similar water deficits, as indicated by the decline in relative water content and water potentials, but they had different effects on ABA accumulation. There was a rapid increase in ABA levels in the leaves of water-deprived plants while only slight ABA accumulation was observed after 48 h of chilling (4{degree}C). After 24 h cold treatment there were large changes in turgor but no change in ABA content. Plants chilled for 24 h accumulated ABA only when transferred to recovery conditions (20{degree}C, 90-95% RH, in the dark) to an extent that was related to the rate of leaf rehydration. When the chilling treatment was performed in a water-saturated atmosphere, plants did not suffer any water stress and ABA levels did not increase over a period of 48 h. However, when the chilling treatment lasted for a longer period (72 h), a significant increase in ABA levels was found also in the absence of water deficit. Experiments performed with leaf discs incubated in a mannitol solution (osmotic potential {minus}1{center dot}6 MPa) at different temperatures indicated that low temperature markedly inhibits ABA synthesis and that water stress induces increases in ABA content only at non-limiting warm temperatures.

  3. Chilling temperature stimulates growth, gene over-expression and podophyllotoxin biosynthesis in Podophyllum hexandrum Royle.

    PubMed

    Yang, De Long; Sun, Ping; Li, Meng Fei

    2016-10-01

    Podophyllotoxin (PPT) and its derivatives, isolated from the rhizome of Podophyllum hexandrum Royle (P. hexandrum), are typically used in clinical settings for anti-cancer and anti-virus treatments. Empirical studies have verified that P. hexandrum had stronger tolerance to chilling, due to involving PPT accumulation in rhizome induced by cold stress. However, the cold-adaptive mechanism and its association with PPT accumulation at a molecular level in P. hexandrum are still limited. In this study, the morpho-physiological traits related to plant growth, PPT accumulation and key gene expressions controlling PPT biosynthesis were assessed by exposing P. hexandrum seedlings to different temperatures (4 °C and 10 °C as chilling stress and 22 °C as the control). The results showed that chilling significantly increased chlorophyll content, net photosynthetic rate, stomatal conductance, and plant biomass, whereas it greatly decreased transpiration rates and intercellular CO2 concentration. Compared to the control, the chilling treatments under 4 °C and 10 °C conditions induced a 5.00- and 3.33-fold increase in PPT contents, respectively. The mRNA expressions of six key genes were also up-regulated by chilling stresses. The findings are useful in understanding the molecular basis of P. hexandrum response to chilling.

  4. Chilling temperature stimulates growth, gene over-expression and podophyllotoxin biosynthesis in Podophyllum hexandrum Royle.

    PubMed

    Yang, De Long; Sun, Ping; Li, Meng Fei

    2016-10-01

    Podophyllotoxin (PPT) and its derivatives, isolated from the rhizome of Podophyllum hexandrum Royle (P. hexandrum), are typically used in clinical settings for anti-cancer and anti-virus treatments. Empirical studies have verified that P. hexandrum had stronger tolerance to chilling, due to involving PPT accumulation in rhizome induced by cold stress. However, the cold-adaptive mechanism and its association with PPT accumulation at a molecular level in P. hexandrum are still limited. In this study, the morpho-physiological traits related to plant growth, PPT accumulation and key gene expressions controlling PPT biosynthesis were assessed by exposing P. hexandrum seedlings to different temperatures (4 °C and 10 °C as chilling stress and 22 °C as the control). The results showed that chilling significantly increased chlorophyll content, net photosynthetic rate, stomatal conductance, and plant biomass, whereas it greatly decreased transpiration rates and intercellular CO2 concentration. Compared to the control, the chilling treatments under 4 °C and 10 °C conditions induced a 5.00- and 3.33-fold increase in PPT contents, respectively. The mRNA expressions of six key genes were also up-regulated by chilling stresses. The findings are useful in understanding the molecular basis of P. hexandrum response to chilling. PMID:27314513

  5. A missense mutation in CHS1, a TIR-NB protein, induces chilling sensitivity in Arabidopsis.

    PubMed

    Wang, Yuancong; Zhang, Yao; Wang, Zheng; Zhang, Xiaoyan; Yang, Shuhua

    2013-08-01

    Low temperature is an environmental factor that affects plant growth and development and plant-pathogen interactions. How temperature regulates plant defense responses is not well understood. In this study, we characterized chilling-sensitive mutant 1 (chs1), and functionally analyzed the role of the CHS1 gene in plant responses to chilling stress. The chs1 mutant displayed a chilling-sensitive phenotype, and also displayed defense-associated phenotypes, including extensive cell death, the accumulation of hydrogen peroxide and salicylic acid, and an increased expression of PR genes: these phenotypes indicated that the mutation in chs1 activates the defense responses under chilling stress. A map-based cloning analysis revealed that CHS1 encodes a TIR-NB-type protein. The chilling sensitivity of chs1 was fully rescued by pad4 and eds1, but not by ndr1. The overexpression of the TIR and NB domains can suppress the chs1-conferred phenotypes. Interestingly, the stability of the CHS1 protein was positively regulated by low temperatures independently of the 26S proteasome pathway. This study revealed the role of a TIR-NB-type gene in plant growth and cell death under chilling stress, and suggests that temperature modulates the stability of the TIR-NB protein in Arabidopsis.

  6. Effect of chilling, polyphosphate and bicarbonate on quality characteristics of broiler breast meat.

    PubMed

    Sen, A R; Naveena, B M; Muthukumar, M; Babji, Y; Murthy, T R K

    2005-08-01

    1. An experiment was conducted to assess the effect of tetrasodium pyrophosphate and sodium bicarbonate on colour and sensory attributes of pre- and post-chilled breast meat. 2. Three groups of 6 halves of breasts (pre-chill) immediately after slaughter were treated with 3% tetrasodium pyrophosphate, 3% sodium bicarbonate in 2% NaCl or 2% NaCl alone (control); the remaining 6 halves (post-chill) were stored overnight at 4 degrees C and then treated similarly. Both the pre- and post-chill samples were held at 4 degrees C for 24 h and pH, water holding capacity, cooking loss, CIE colour values and sensory attributes were recorded. 3. Chilling had few effects on the meat characteristics measured in this study. 4. Treatment with phosphate and bicarbonate increased pH in both the pre- and post-chill groups. Treated breasts exhibited lower L* and higher a* value (more red) than controls. 5. A sensory evaluation study revealed improvements in colour and other sensory attributes of cooked broiler breast meat in all treated samples compared to the control. 6. The findings suggest that tetrasodium pyrophosphate and sodium bicarbonate, when injected post mortem, will have beneficial effects on several physico-chemical (pH, colour, WHC %, cooking loss) and sensory attributes of broiler meat. However, phosphate had a smaller effect than bicarbonate.

  7. An evaluation of the wind chill factor: its development and applicability.

    PubMed

    Bluestein, M

    1998-04-01

    The wind chill factor has become a standard meteorologic term in cold climates. Meteorologic charts provide wind chill temperatures meant to represent the hypothetical air temperature that would, under conditions of no wind, effect the same heat loss from unclothed human skin as does the actual combination of air temperature and wind velocity. As this wind chill factor has social and economic significance, an investigation was conducted on the development of this factor and its applicability based on modern heat transfer principles. The currently used wind chill factor was found to be based on a primitive study conducted by the U.S. Antarctic Service over 50 years ago. The resultant equation for the wind chill temperature assumes an unrealistic constant skin temperature and utilizes heat transfer coefficients that differ markedly from those obtained from equations of modern convective heat transfer methods. The combined effect of these two factors is to overestimate the effect of a given wind velocity and to predict a wind chill temperature that is too low.

  8. Metabolism and energy supply below the critical thermal minimum of a chill-susceptible insect.

    PubMed

    Macmillan, Heath A; Williams, Caroline M; Staples, James F; Sinclair, Brent J

    2012-04-15

    When exposed to temperatures below their critical thermal minimum (CT(min)), insects enter chill-coma and accumulate chilling injuries. While the critical thermal limits of water-breathing marine animals may be caused by oxygen- and capacity-limitation of thermal tolerance (OCLT), the mechanisms are poorly understood in air-breathing terrestrial insects. We used thermolimit respirometry to characterize entry into chill-coma in a laboratory population of fall field crickets (Gryllus pennsylvanicus). To detect potential oxygen limitation, we quantified muscle ATP, lactate and alanine concentrations in crickets following prolonged exposure to 0°C (a temperature that causes chill-coma, chilling injury and eventual death). Although there was a sharp (44%) drop in the rate of CO(2) emission at the CT(min) and spiracular control was lost, there was a low, continuous rate of CO(2) release throughout chill-coma, indicating that the spiracles were open and gas exchange could occur through the tracheal system. Prolonged exposure to 0°C caused muscle ATP levels to increase marginally (rather than decrease as OCLT would predict), and there was no change in muscle lactate or alanine concentration. Thus, it appears that insects are not susceptible to OCLT at low temperatures but that the CT(min) may instead be set by temperature effects on whole-animal ion homeostasis. PMID:22442375

  9. Fillability of Thin-Wall Steel Castings

    SciTech Connect

    Robert C. Voigt; Joseph Bertoletti; Andrew Kaley; Sandi Ricotta; Travis Sunday

    2002-07-30

    The use of steel components is being challenged by lighter nonferrous or cast iron components. The development of techniques for enhancing and ensuring the filability of thin-wall mold cavities is most critical for thinner wall cast steel production. The purpose of this research was to develop thin-wall casting techniques that can be used to reliably produce thin-wall castings from traditional gravity poured sand casting processes. The focus of the research was to enhance the filling behavior to prevent misrunds. Experiments were conducted to investigate the influence of various foundry variables on the filling of thin section steel castings. These variables include casting design, heat transfer, gating design, and metal fluidity. Wall thickness and pouring temperature have the greatest effect on casting fill. As wall thickness increases the volume to surface area of the casting increases, which increases the solidification time, allowing the metal to flow further in thicker sect ions. Pouring time is another significant variable affecting casting fill. Increases or decreases of 20% in the pouring time were found to have a significant effect on the filling of thin-wall production castings. Gating variables, including venting, pouring head height, and mold tilting also significantly affected thin-wall casting fill. Filters offer less turbulent, steadier flow, which is appropriate for thicker castings, but they do not enhance thin-wall casting fill.

  10. Assessment of the effects of environmental radiation on wind chill equivalent temperatures.

    PubMed

    Shitzer, Avraham

    2008-09-01

    Combinations of wind-driven convection and environmental radiation in cold weather, make the environment "feel" colder. The relative contributions of these mechanisms, which form the basis for estimating wind chill equivalent temperatures (WCETs), are studied over a wide range of environmental conditions. Distinction is made between direct solar radiation and environmental radiation. Solar radiation, which is not included in the analysis, has beneficial effects, as it counters and offsets some of the effects due to wind and low air temperatures. Environmental radiation effects, which are included, have detrimental effects in enhancing heat loss from the human body, thus affecting the overall thermal sensation due to the environment. The analysis is performed by a simple, steady-state analytical model of human-environment thermal interaction using upper and lower bounds of environmental radiation heat exchange. It is shown that, over a wide range of relevant air temperatures and reported wind speeds, convection heat losses dominate over environmental radiation. At low wind speeds radiation contributes up to about 23% of the overall heat loss from exposed skin areas. Its relative contributions reduce considerably as the time of the exposure prolongs and exposed skin temperatures drop. At still higher wind speeds, environmental radiation effects become much smaller contributing about 5% of the total heat loss. These values fall well within the uncertainties associated with the parameter values assumed in the computation of WCETs. It is also shown that environmental radiation effects may be accommodated by adjusting reported wind speeds slightly above their reported values.

  11. Cast adrift: Gortex cast liners allow greater patient activity.

    PubMed

    Dubowitz, Gerald; Miller, Deborah M

    2003-01-01

    Extremity fractures are a common injury, with nearly 1.5 million cases reported in the United States in 1998. Treatment often involves lengthy periods of immobilization. This report outlines the use of a Gortex cast liner by a subject who was able to engage in swimming and scuba diving during the healing process. We report that a Gortex cast liner may be considered for an active patient who is keen to return to limited activities during fracture healing. Apparently because of a lack of knowledge of their existence, physicians currently are underutilizing this method of casting in active patients. The use of Gortex liners elsewhere has been reported to have higher patient and physician satisfaction in both use and performance, with no reported detrimental effects on outcome.

  12. Solvent-cast three-dimensional printing of multifunctional microsystems.

    PubMed

    Guo, Shuang-Zhuang; Gosselin, Frédérick; Guerin, Nicolas; Lanouette, Anne-Marie; Heuzey, Marie-Claude; Therriault, Daniel

    2013-12-20

    The solvent-cast direct-write fabrication of microstructures is shown using a thermoplastic polymer solution ink. The method employs the robotically controlled microextrusion of a filament combined with a rapid solvent evaporation. Upon drying, the increased rigidity of the extruded filament enables the creation of complex freeform 3D shapes.

  13. Use of methanol as cryoprotectant and its effect on sox genes and proteins in chilled zebrafish embryos.

    PubMed

    Desai, Kunjan; Spikings, Emma; Zhang, Tiantian

    2015-08-01

    Methanol is a widely used cryoprotectant (CPA) in cryopreservation of fish embryos, however little is known about its effect at the molecular level. This study investigated the effect of methanol on sox gene and protein expression in zebrafish embryos (50% epiboly) when they were chilled for 3 h and subsequently warmed and cultured to the hatching stages. Initial experiments were carried out to evaluate the chilling tolerance of 50% epiboly embryos which showed no significant differences in hatching rates for up to 6 h chilling in methanol (0.2-, 0.5- and 1 M). Subsequent experiments in embryos that had been chilled for 3 h in 1 M methanol and warmed and cultured up to the hatching stages found that sox2 and sox3 gene expression were increased significantly in hatched embryos that had been chilled compared to non-chilled controls. Sox19a gene expression also remained above control levels in the chilled embryos at all developmental stages tested. Whilst stable sox2 protein expression was observed between non-chilled controls and embryos chilled for 3 h with or without MeOH, a surge in sox19a protein expression was observed in embryos chilled for 3 h in the presence of 1 M MeOH compared to non-chilled controls and then returned to control levels by the hatching stage. The protective effect of MeOH was increased with increasing concentrations. Effect of methanol at molecular level during chilling was reported here first time which could add new parameter in selection of cryoprotectant while designing cryopreservation protocol.

  14. Geographic Variations in Chilled Margin Chemistry of Jurassic Dolerite Intrusions in the Dry Valley Region of South Victoria Land, Antarctica

    NASA Astrophysics Data System (ADS)

    Fleming, T. H.; Elliot, D. H.; Calhoun, A.

    2005-12-01

    stratigraphically higher sills in the eastern Quartermain Mtns have significantly more evolved chemical compositions that cluster around SiO2=57.5%, MgO=4.3%, TiO2=1.0%, Zr=165 ppm. A sequence of dikes in the southeastern Quartermain Mtns that cross cut sills in that region have compositions similar to the basement and peneplain sills in the Bull Pass region. The complete suite of compositions from both regions can be easily related by simple low-pressure gabbro fractionation. Existing correlations between the Taylor Valley and Bull Pass region requires extrapolation through the poorly exposed and largely ice covered Asgard Range (~15 km). Differences in the compositions of the basement and peneplain sills in each region hint at the possibility that they may be different intrusions. Alternatively, if the existing correlations are correct, our results document a trend of increasingly more evolved chilled margin compositions to the south in both the basement and peneplain sills. If the chilled margins of sills become more evolved away from their initial filling conduit as a result of differentiation processes operating during emplacement, the observed chemical trends would be consistent with a source located in the direction of the Bull Pass region as proposed by Marsh (2004). Marsh, B. (2004) A Magmatic Mush Column Rosetta Stone: the McMurdo Dry Valleys of Antarctica, EOS, 85(47) 497-508.

  15. Chilled disks in ultraluminous X-ray sources

    NASA Astrophysics Data System (ADS)

    Soria, Roberto; Kuncic, Zdenka; Gonçalves, Anabela C.

    2007-04-01

    The "soft-excess" component fitted to the X-ray spectra of many ultraluminous X-ray sources (ULXs) remains a controversial finding, which may reveal fundamental information either on the black hole (BH) mass or on the state of the accretion flow. In the simplest model, it was explained as thermal emission from a cool accretion disk around an intermediate-mass BH (about 1000 solar masses). We argue that this scenario is highly implausible, and discuss and compare the two most likely alternatives. 1) The soft-excess does come from a cool disk; however, the temperature is low not because of a high BH mass but because most of the accretion power is drained from the inner disk via magnetic torques, and channelled into jets and outflows ("chilled disk" scenario). Using a phenomenological model, we infer that ULXs contain BHs of about 50 solar masses accreting gas at about 10 times their Eddington rate. 2) The soft excess is in fact a soft deficit, if the power-law continuum is properly fitted. Such broad absorption features are caused by smeared absorption lines in fast, highly ionized outflows. This scenario has already been successfully applied to the soft excess in AGN. If so, this spectral feature reveals details of disk outflows,but is unrelated to the BH mass.

  16. Ultrasonic measurement of porosity in casts and welds

    NASA Technical Reports Server (NTRS)

    Adler, L.; Wang, S. W.

    1986-01-01

    The development of a quantitative nondestructive method which involves ultrasonic attenuation measurements in frequency domain to determine volume fraction of porosity in aluminum cast is discussed. The aluminum alloy A357 casting samples were produced at the Ohio State University Foundry with controlled porosity contents ranging from 0% to 6%. A computer controlled system was used to direct ultrasonic beam to a test sample to different places to conduct ultrasonic attenuation measurements. The plot of attenuation coefficients as a function of frequency was then evaluated based on existing theories to determine volume fraction of porosity and pore size.

  17. Economic analysis of air-conditioning systems with off-peak chilled-water storage. Master's thesis

    SciTech Connect

    McMullen, B.J.; Papaprokopiou, N.D.

    1981-09-01

    This thesis investigates current methods of chilled-water storage for air conditioning applications and the economics of chilled-water storage with time-of-use electric utility rates. Current methods of chilled-water storage are investigated by comparing costs of construction materials for storage tanks and effectiveness and costs of anti-blending systems. The economics of chilled-water storage are analyzed by computing total life cycle costs of alternative air conditioning systems for two different sized buildings. Computer simulation is used to determine electric consumption for the buildings. The simulation of each building contains three options: no chilled-water storage, chiller operated only at night, and a small chiller supplemented by stored chilled-water. A gunite or Styrofoam tank with a moving partition anti-blending system is the least expensive and most effective storage system. The economics of chilled-water storage are sensitive to the size of the building analyzed. Operating the small chiller with supplemental chilled-water is economical in the smaller building. No chilled-water storage is the most economical option in the larger building. Operation of the chiller only at night was never economical.

  18. Chilling requirements for hatching of a New Zealand isolate of Nematodirus filicollis.

    PubMed

    Oliver, A-M B; Pomroy, W E; Ganesh, S; Leathwick, D M

    2016-08-15

    The eggs of some species of the parasitic nematode Nematodirus require a period of chilling before they can hatch; N. filicollis is one such species. This study investigated this requirement for chilling in a New Zealand strain of this species. Eggs of N. filicollis were extracted from lamb's faeces and incubated at 20°C to allow development to the third stage larvae within the egg. These eggs were then placed into tissue culture plates and incubated at: 2.7°C (±0.99), 3.6°C (±0.90), 4.7°C (±0.35), 6.4°C (±0.37), 8.0°C (±1.54) or 9.9°C (±0.14) for up to 224 days. At 14day intervals until day 84, then every 28 days, one plate was removed from each temperature and placed at 13.1°C (±0.44) for 14 days. Eggs were then assessed for hatching. From this data, chill units were calculated by subtracting the culture temperature from a constant threshold of 11°C and multiplying by the number of days for which the sample was cultured; then the Gompertz model fitted. Even though hatching overall was low, a greater proportion of eggs hatched with chill accumulation. Maximum hatching of eggs required 800-1000 chill units. Consequently in the field, more than one season of chilling would be required before hatching. As such a generation time could take more than one year to complete. This is different to the hatching dynamics of N. spathiger, the other main species found in New Zealand sheep, which does not display this requirement for chilling and hatches immediately once the third stage larvae are developed. PMID:27514876

  19. Chilling requirements for hatching of a New Zealand isolate of Nematodirus filicollis.

    PubMed

    Oliver, A-M B; Pomroy, W E; Ganesh, S; Leathwick, D M

    2016-08-15

    The eggs of some species of the parasitic nematode Nematodirus require a period of chilling before they can hatch; N. filicollis is one such species. This study investigated this requirement for chilling in a New Zealand strain of this species. Eggs of N. filicollis were extracted from lamb's faeces and incubated at 20°C to allow development to the third stage larvae within the egg. These eggs were then placed into tissue culture plates and incubated at: 2.7°C (±0.99), 3.6°C (±0.90), 4.7°C (±0.35), 6.4°C (±0.37), 8.0°C (±1.54) or 9.9°C (±0.14) for up to 224 days. At 14day intervals until day 84, then every 28 days, one plate was removed from each temperature and placed at 13.1°C (±0.44) for 14 days. Eggs were then assessed for hatching. From this data, chill units were calculated by subtracting the culture temperature from a constant threshold of 11°C and multiplying by the number of days for which the sample was cultured; then the Gompertz model fitted. Even though hatching overall was low, a greater proportion of eggs hatched with chill accumulation. Maximum hatching of eggs required 800-1000 chill units. Consequently in the field, more than one season of chilling would be required before hatching. As such a generation time could take more than one year to complete. This is different to the hatching dynamics of N. spathiger, the other main species found in New Zealand sheep, which does not display this requirement for chilling and hatches immediately once the third stage larvae are developed.

  20. Morphological castes in a vertebrate.

    PubMed

    O'Riain, M J; Jarvis, J U; Alexander, R; Buffenstein, R; Peeters, C

    2000-11-21

    Morphological specialization for a specific role has, until now, been assumed to be restricted to social invertebrates. Herein we show that complete physical dimorphism has evolved between reproductives and helpers in the eusocial naked mole-rat. Dimorphism is a consequence of the lumbar vertebrae lengthening after the onset of reproduction in females. This is the only known example of morphological castes in a vertebrate and is distinct from continuous size variation between breeders and helpers in other species of cooperatively breeding vertebrates. The evolution of castes in a mammal and insects represents a striking example of convergent evolution for enhanced fecundity in societies characterized by high reproductive skew. Similarities in the selective environment between naked mole-rats and eusocial insect species highlight the selective conditions under which queen/worker castes are predicted to evolve in animal societies.

  1. Green Turning of FCD 700 Ductile Cast Iron Using Coated Carbide Tool

    NASA Astrophysics Data System (ADS)

    Rodzi, Mohd Nor Azmi Mohd; Ghani, Jaharah A.; Eghawail, A. M.; Othman, Kamal; Rahman, Mohd. Nizam Ab.; Haron, Che Hassan Che

    2010-10-01

    This paper presents the performance of carbide coated cutting insert in turning FCD700 ductile cast iron in various dry machining conditions (without air, using air and chilled air). The turning parameters studied were, cutting speed of 120 m/min., feed rate of 0.15 mm/rev-0.4 mm/rev, and depth of cut of 0.6 mm-1.0 mm. The results show that the tool life was significantly controlled by the type of air coolant used, whereas the cutting force and surface roughness were not influenced by these coolants. Chilled air was found to be significantly improved the tool life by about 30% and 40% respectively when compared with normal air and without air conditions. The wear mechanism was predominantly controlled by the flank and crater wears on the flank and rake faces respectively. Due to the low cutting speed used in the experiment, both flank and crater wears were uniformly formed along the cutting edge and no catastrophic failure was observed under the scanning electron microscope (SEM).

  2. CAST-10-2/DOA 2 Airfoil Studies Workshop Results

    NASA Technical Reports Server (NTRS)

    Ray, Edward J. (Compiler); Hill, Acquilla S. (Compiler)

    1989-01-01

    During the period of September 23 through 27, 1988, the Transonic Aerodynamics Division at the Langely Research Center hosted an International Workshop on CAST-10-2/DOA 2 Airfoil Studies. The CAST-10 studies were the outgrowth of several cooperative study agreements among the NASA, the NAE of Canada, the DLR of West Germany, and the ONERA of France. Both theoretical and experimental CAST-10 airfoil results that were obtained form an extensive series of tests and studies, were reviewed. These results provided an opportunity to make direct comparisons of adaptive wall test section (AWTS) results from the NASA 0.3-meter Transonic Cryogenic Tunnel and ONERA T-2 AWTS facilities with conventional ventilated wall wind tunnel results from the Canadian high Reynolds number two-dimensional test facility. Individual papers presented during the workshop are included.

  3. Robust and Rapid Air-Borne Odor Tracking without Casting.

    PubMed

    Bhattacharyya, Urvashi; Bhalla, Upinder Singh

    2015-01-01

    Casting behavior (zigzagging across an odor stream) is common in air/liquid-borne odor tracking in open fields; however, terrestrial odor localization often involves path selection in a familiar environment. To study this, we trained rats to run toward an odor source in a multi-choice olfactory arena with near-laminar airflow. We find that rather than casting, rats run directly toward an odor port, and if this is incorrect, they serially sample other sources. This behavior is consistent and accurate in the presence of perturbations, such as novel odors, background odor, unilateral nostril stitching, and turbulence. We developed a model that predicts that this run-and-scan tracking of air-borne odors is faster than casting, provided there are a small number of targets at known locations. Thus, the combination of best-guess target selection with fallback serial sampling provides a rapid and robust strategy for finding odor sources in familiar surroundings. PMID:26665165

  4. Robust and Rapid Air-Borne Odor Tracking without Casting.

    PubMed

    Bhattacharyya, Urvashi; Bhalla, Upinder Singh

    2015-01-01

    Casting behavior (zigzagging across an odor stream) is common in air/liquid-borne odor tracking in open fields; however, terrestrial odor localization often involves path selection in a familiar environment. To study this, we trained rats to run toward an odor source in a multi-choice olfactory arena with near-laminar airflow. We find that rather than casting, rats run directly toward an odor port, and if this is incorrect, they serially sample other sources. This behavior is consistent and accurate in the presence of perturbations, such as novel odors, background odor, unilateral nostril stitching, and turbulence. We developed a model that predicts that this run-and-scan tracking of air-borne odors is faster than casting, provided there are a small number of targets at known locations. Thus, the combination of best-guess target selection with fallback serial sampling provides a rapid and robust strategy for finding odor sources in familiar surroundings.

  5. Caste load and the evolution of reproductive skew.

    PubMed

    Holman, Luke

    2014-01-01

    Reproductive skew theory seeks to explain how reproduction is divided among group members in animal societies. Existing theory is framed almost entirely in terms of selection, though nonadaptive processes must also play some role in the evolution of reproductive skew. Here I propose that a genetic correlation between helper fecundity and breeder fecundity may frequently constrain the evolution of reproductive skew. This constraint is part of a wider phenomenon that I term "caste load," which is defined as the decline in mean fitness caused by caste-specific selection pressures, that is, differential selection on breeding and nonbreeding individuals. I elaborate the caste load hypothesis using quantitative and population genetic arguments and individual-based simulations. Although selection can sometimes erode genetic correlations and resolve caste load, this may be constrained when mutations have similar pleiotropic effects on breeder and helper traits. I document evidence for caste load, identify putative genomic adaptations to it, and suggest future research directions. The models highlight the value of considering adaptation within the boundaries imposed by genetic architecture and incidentally reaffirm that monogamy promotes the evolutionary transition to eusociality. PMID:24334738

  6. Energy Consumption of Die Casting Operations

    SciTech Connect

    Jerald Brevick; clark Mount-Campbell; Carroll Mobley

    2004-03-15

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

  7. Effects of Antimony and Wall Thickness on Graphite Morphology in Ductile Iron Castings

    NASA Astrophysics Data System (ADS)

    Glavas, Zoran; Strkalj, Anita; Maldini, Kresimir

    2016-08-01

    Effects of Sb additions on the graphite morphology of ductile iron castings in different wall thicknesses (3, 12, 25, 38, 50, 75, and 100 mm) were analyzed in this paper. In the wall thicknesses of 3, 12, and 25 mm, low contents of rare earth (RE) elements showed a beneficial effect on nodule count and nodularity. Nodularity >80 pct and a high nodule count were achieved without the addition of Sb. In the wall thicknesses of 38, 50, 75, and 100 mm, nodularity >80 pct was not achieved without the use of the chill or proper content of Sb. Excess of RE elements was neutralized with the addition of proper amount of Sb to the wall thickness. Addition of 0.01 wt pct Sb (ratio of RE/Sb = 0.34, ratio of RE/SE = 0.105) was sufficient to achieve nodularity >80 pct in the wall thicknesses of 38, 50, 75, and 100 mm.

  8. Casting propellant in rocket engine

    NASA Technical Reports Server (NTRS)

    Roach, J. E.; Froehling, S. C. (Inventor)

    1976-01-01

    A method is described for casting a solid propellant in the casing of a rocket engine having a continuous wall with a single opening which is formed by leaves of a material which melt at a temperature of the propellant and with curved edges concentric to the curvature of the spherical casing. The leaves are inserted into the spherical casing through the opening forming a core having a greater width than the width of the single opening and with curved peripheral edges. The cast propellant forms a solid mass and then heated to melt the leaves and provide a central opening with radial projecting flutes.

  9. Chilling rate effects on pork loin tenderness in commercial processing plants.

    PubMed

    Shackelford, S D; King, D A; Wheeler, T L

    2012-08-01

    The present experiment was conducted to provide a large-scale objective comparison of pork LM tenderness and other meat quality traits among packing plants that differ in stunning method and carcass chilling rate. For each of 2 replicates, pigs were sourced from a single barn of a commercial finishing operation that fed pigs from a single terminal crossbred line. On each day, 3 trucks were loaded, with each of those trucks delivering the pigs to a different plant. Plant A used CO(2) stunning and conventional spray chilling; Plant B used CO(2) stunning and blast chilling; and Plant C used electrical stunning and blast chilling. The boneless, vacuum-packaged loin was obtained from the left side of each carcass (n = 597; 100 · plant(-1) · replicate(-1)). As designed, HCW, LM depth, and LM intramuscular fat percentage did not differ among plants (P > 0.05). By 1.67 h postmortem (1 h after the carcasses exited the harvest floor), the average deep LM temperature was >10°C warmer for Plant A than Plants B and C (32.1°C, 21.6°C, and 19.3°C, for Plants A, B, and C, respectively) and deep LM temperature continued to be >10°C warmer for Plant A until 4.17 h or 6.33 h postmortem than for Plants C and B, respectively. Both plants that used blast chilling produced loins with greater LM slice shear force at 15 d postmortem than did the plant that used conventional spray chilling (P < 0.0001). The frequency of loins with excessively high (>25 kg) LM slice shear force values was greater for Plant B than Plant A (14.7% vs. 1%; P < 0.01). Among all the traits studied, including visual and instrumental evaluations of LM color, ultimate pH, marbling score, and lean color stability, the only other difference between Plants A and B was that purge loss during 13 d (from d 1 to 14) of vacuum-packaged storage was greater for Plant B (P < 0.05). That is, with this sample of pigs and CO(2) stunning, no loin quality advantages were detected for blast chilling. Regardless of chilling

  10. Osmoconditioning reduces physiological and biochemical damage induced by chilling in soybean seeds.

    PubMed

    Posmyk, Malgorzata Maria; Corbineau, Françoise; Vinel, Dominique; Bailly, Christophe; Côme, Daniel

    2001-04-01

    The aim of the present work was to investigate the effects of osmoconditioning on chilling injury in soybean (Glycine max (L.) Merr.) seeds during imbibition. Soybean seeds germinated readily over a large range of temperatures (10-35 degrees C), the thermal optimum being 25-30 degrees C. Low temperatures reduced the germination rate and no seed germinated at 1 degrees C. Pre-treatment of seeds at 1 degrees C reduced further germination at the optimal temperature (25 degrees C). This deleterious effect of chilling increased with duration of the treatment, and was maximal after 4 days. Osmoconditioning of seeds at 20 degrees C with a polyethylene glycol-8000 solution at -1.5 MPa for at least 24 h followed by drying back the seeds to their initial moisture content reduced their chilling sensitivity and even allowed germination at 1 degrees C. Chilling of control seeds resulted in a sharp decline in in vivo ACC-dependent ethylene production and in an increase in electrolyte leakage in the medium, which indicated deterioration of membrane properties. Osmoconditioned seeds placed at 1 degrees C did not show any reduction in their ability to convert ACC to ethylene nor any strong increase in electrolyte leakage. Imbibition of both control and osmoconditioned seeds at 1 degrees C resulted in a marked increase in ATP level (more than 50% of the total nucleotides) and energy charge; however, the latter cannot be considered as an indicator of chilling since it remained high (0.74-0.88) throughout the cold treatment. Chilling treatment longer than 6 days induced accumulation of malondialdehyde in the embryonic axis, which was more marked in control seeds than in osmoconditioned seeds, suggesting that chilling sensitivity was associated with lipid peroxidation. Imbibition of seeds at 1 degrees C resulted in an increase in superoxide dismutase, catalase and glutathione reductase activity, which was generally higher in osmoconditioned seeds than in control ones. This stimulation

  11. INTERIOR VIEW WITH CASTING MACHINE AND A 4' DUCTILE IRON ...

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

    INTERIOR VIEW WITH CASTING MACHINE AND A 4' DUCTILE IRON PIPE BEING CENTRIFUGALLY CAST, AS OPERATOR WATCHES TO ENSURE QUALITY. - McWane Cast Iron Pipe Company, Pipe Casting Area, 1201 Vanderbilt Road, Birmingham, Jefferson County, AL

  12. INTERIOR VIEW OF CASTING MACHINE WITH 4' DUCTILE IRON PIPE ...

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

    INTERIOR VIEW OF CASTING MACHINE WITH 4' DUCTILE IRON PIPE BEING WEIGHED ON SCALES AT CASTING MACHINE. - McWane Cast Iron Pipe Company, Pipe Casting Area, 1201 Vanderbilt Road, Birmingham, Jefferson County, AL

  13. INTERIOR VIEW WITH CASTING MACHINE AND A 4" DUCTILE IRON ...

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

    INTERIOR VIEW WITH CASTING MACHINE AND A 4" DUCTILE IRON PIPE BEING EXTRACTED FROM CASTING MACHINE - McWane Cast Iron Pipe Company, Pipe Casting Area, 1201 Vanderbilt Road, Birmingham, Jefferson County, AL

  14. INTERIOR VIEW WITH CASTING MACHINE COOLING A 20' IRON PIPE ...

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

    INTERIOR VIEW WITH CASTING MACHINE COOLING A 20' IRON PIPE PRIOR TO EXTRACTION FROM CASTING MACHINE. - McWane Cast Iron Pipe Company, Pipe Casting Area, 1201 Vanderbilt Road, Birmingham, Jefferson County, AL

  15. Sodium distribution predicts the chill tolerance of Drosophila melanogaster raised in different thermal conditions.

    PubMed

    MacMillan, Heath A; Andersen, Jonas L; Loeschcke, Volker; Overgaard, Johannes

    2015-05-15

    Many insects, including the model holometabolous insect Drosophila melanogaster, display remarkable plasticity in chill tolerance in response to the thermal environment experienced during development or as adults. At low temperatures, many insects lose the ability to regulate Na(+) balance, which is suggested to cause a secondary loss of hemolymph water to the tissues and gut lumen that concentrates the K(+) remaining in the hemolymph. The resultant increase in extracellular [K(+)] inhibits neuromuscular excitability and is proposed to cause cellular apoptosis and injury. The present study investigates whether and how variation in chill tolerance induced through developmental and adult cold acclimation is associated with changes in Na(+), water, and K(+) balance. Developmental and adult cold acclimation improved the chilling tolerance of D. melanogaster in an additive manner. In agreement with the proposed model, these effects were intimately related to differences in Na(+) distribution prior to cold exposure, such that chill-tolerant flies had low hemolymph [Na(+)], while intracellular [Na(+)] was similar among treatment groups. The low hemolymph Na(+) of cold-acclimated flies allowed them to maintain hemolymph volume, prevent hyperkalemia, and avoid injury following chronic cold exposure. These findings extend earlier observations of hemolymph volume disruption during cold exposure to the most ubiquitous model insect (D. melanogaster), highlight shared mechanisms of developmental and adult thermal plasticity and provide strong support for ionoregulatory failure as a central mechanism of insect chill susceptibility.

  16. Quantitative Phosphoproteomics Reveals Signaling Mechanisms Associated with Rapid Cold Hardening in a Chill-Tolerant Fly.

    PubMed

    Teets, Nicholas M; Denlinger, David L

    2016-08-01

    Rapid cold hardening (RCH) is a physiological adaptation in which brief chilling (minutes to hours) significantly enhances the cold tolerance of insects. RCH allows insects to cope with sudden cold snaps and diurnal variation in temperature, but the mechanistic basis of this rapid stress response is poorly understood. Here, we used phosphoproteomics to identify phosphorylation-mediated signaling events that are regulated by chilling that induces RCH. Phosphoproteomic changes were measured in both brain and fat bodies, two tissues that are essential for sensing cold and coordinating RCH at the organismal level. Tissues were chilled ex vivo, and changes in phosphoprotein abundance were measured using 2D electrophoresis coupled with Pro-Q diamond labeling of phosphoproteins followed by protein identification via LC-MS/MS. In both tissues, we observed an abundance of protein phosphorylation events in response to chilling. Some of the proteins regulated by RCH-inducing chilling include proteins involved in cytoskeletal reorganization, heat shock proteins, and proteins involved in the degradation of damaged cellular components via the proteasome and autophagosome. Our results suggest that phosphorylation-mediated signaling cascades are major drivers of RCH and enhance our mechanistic understanding of this complex phenotype.

  17. Identification of Clathrate Hydrates, Hexagonal Ice, Cubic Ice, and Liquid Water in Simulations: the CHILL+ Algorithm.

    PubMed

    Nguyen, Andrew H; Molinero, Valeria

    2015-07-23

    Clathrate hydrates and ice I are the most abundant crystals of water. The study of their nucleation, growth, and decomposition using molecular simulations requires an accurate and efficient algorithm that distinguishes water molecules that belong to each of these crystals and the liquid phase. Existing algorithms identify ice or clathrates, but not both. This poses a challenge for cases in which ice and hydrate coexist, such as in the synthesis of clathrates from ice and the formation of ice from clathrates during self-preservation of methane hydrates. Here we present an efficient algorithm for the identification of clathrate hydrates, hexagonal ice, cubic ice, and liquid water in molecular simulations. CHILL+ uses the number of staggered and eclipsed water-water bonds to identify water molecules in cubic ice, hexagonal ice, and clathrate hydrate. CHILL+ is an extension of CHILL (Moore et al. Phys. Chem. Chem. Phys. 2010, 12, 4124-4134), which identifies hexagonal and cubic ice but not clathrates. In addition to the identification of hydrates, CHILL+ significantly improves the detection of hexagonal ice up to its melting point. We validate the use of CHILL+ for the identification of stacking faults in ice and the nucleation and growth of clathrate hydrates. To our knowledge, this is the first algorithm that allows for the simultaneous identification of ice and clathrate hydrates, and it does so in a way that is competitive with respect to existing methods used to identify any of these crystals. PMID:25389702

  18. Understanding the mechanisms of chilling injury in bell pepper fruits using the proteomic approach.

    PubMed

    Sánchez-Bel, Paloma; Egea, Isabel; Sánchez-Ballesta, María Teresa; Martinez-Madrid, Concepción; Fernandez-Garcia, Nieves; Romojaro, Félix; Olmos, Enrique; Estrella, Emilio; Bolarín, Maria C; Flores, Francisco Borja

    2012-09-18

    In order to advance in the understanding of CI in pepper fruits, the cell ultrastructure alterations induced by CI and the physiological and metabolic changes have been studied along with the proteomic study. When stored at low temperatures bell pepper (Capsicum annuum) fruits exhibited visual CI symptoms and important alterations within the cell ultrastructure, since peroxisomes and starch grains were not detected and the structure of the chloroplast was seriously damaged in chilled tissues. Physiological and metabolic disorders were also observed in chilled fruits, such as higher ethylene production, increased MDA content, changes in sugar and organic acids and enzymatic activities. The comparative proteomic analysis between control and chilled fruits reveals that the main alterations induced by CI in bell pepper fruits are linked to redox homeostasis and carbohydrate metabolism. Thus, protein abundance in the ascorbate-glutathione cycle is altered and catalase is down-regulated. Key proteins from glycolysis, Calvin cycle and Krebs cycle are also inhibited in chilled fruits. Enolase and GAPDH are revealed as proteins that may play a key role in the development of chilling injury. This study also provides the first evidence at the protein level that cytosolic MDH is involved in abiotic stress.

  19. Quantitative Phosphoproteomics Reveals Signaling Mechanisms Associated with Rapid Cold Hardening in a Chill-Tolerant Fly.

    PubMed

    Teets, Nicholas M; Denlinger, David L

    2016-08-01

    Rapid cold hardening (RCH) is a physiological adaptation in which brief chilling (minutes to hours) significantly enhances the cold tolerance of insects. RCH allows insects to cope with sudden cold snaps and diurnal variation in temperature, but the mechanistic basis of this rapid stress response is poorly understood. Here, we used phosphoproteomics to identify phosphorylation-mediated signaling events that are regulated by chilling that induces RCH. Phosphoproteomic changes were measured in both brain and fat bodies, two tissues that are essential for sensing cold and coordinating RCH at the organismal level. Tissues were chilled ex vivo, and changes in phosphoprotein abundance were measured using 2D electrophoresis coupled with Pro-Q diamond labeling of phosphoproteins followed by protein identification via LC-MS/MS. In both tissues, we observed an abundance of protein phosphorylation events in response to chilling. Some of the proteins regulated by RCH-inducing chilling include proteins involved in cytoskeletal reorganization, heat shock proteins, and proteins involved in the degradation of damaged cellular components via the proteasome and autophagosome. Our results suggest that phosphorylation-mediated signaling cascades are major drivers of RCH and enhance our mechanistic understanding of this complex phenotype. PMID:27362561

  20. Effects of rapid chilling of carcasses and time of deboning on weight loss and technological quality of pork semimembranosus muscle.

    PubMed

    Tomović, Vladimir M; Petrović, Ljiljana S; Džinić, Natalija R

    2008-12-01

    The effect of rapid air chilling of carcasses in the first 3 h of chilling at -31°C (then at 2-4°C, till 24 h post-mortem) and the possibility of earlier deboning (8 h post-mortem) after rapid air chilling, compared to conventional air chilling (at 2-4°C, till 24 h post-mortem) on weight loss and technological quality (pH value, tenderness, drip loss, cooking loss and colour - L(∗)a(∗)b(∗) values) of pork M. semimembranosus was investigated. Under the rapid chilling conditions, weight loss was 0.8% at 8 h post-mortem and increased to 1.4% at 24 h post-mortem when weight loss was 2.0% under conventional chilling. Carcasses that were rapid chilled had significantly lower (P<0.001) internal temperature in the deep leg at 4 (25.7°C), 6 (13.0°C), 8 (6.2°C) and 24 h (3.8°C) post-mortem compared to conventional chill treatment (32.7, 24.2, 19.1 and 5.1°C, respectively). Rapid chilling reduced significantly (P<0.05) the rate of pH value decline at 8 h (6.02) post-mortem in M. semimembranosus compared to conventional chill treatment (5.88). Compared to conventional chilling, in M. semimembranosus deboned in different time post-mortem, rapid chilling had a positive significant effect on drip loss (P<0.05, muscles deboned 8 h post-mortem), cooking loss (P<0.001) and incidence of pale colour (L(∗) value). Rapid chilling i.e. rapid chilling and earlier deboning had neither positive nor negative significant effects (P>0.05) on other investigated technological quality parameters of M. semimembranosus (tenderness, a(∗) value and b(∗) value) compared to conventional chilling.

  1. Tomato expressing Arabidopsis glutaredoxin gene AtGRXS17 confers tolerance to chilling stress via modulating cold responsive components.

    PubMed

    Hu, Ying; Wu, Qingyu; Sprague, Stuart A; Park, Jungeun; Oh, Myungmin; Rajashekar, C B; Koiwa, Hisashi; Nakata, Paul A; Cheng, Ninghui; Hirschi, Kendal D; White, Frank F; Park, Sunghun

    2015-01-01

    Chilling stress is a production constraint of tomato, a tropical origin, chilling-sensitive horticultural crop. The development of chilling tolerant tomato thus has significant potential to impact tomato production. Glutaredoxins (GRXs) are ubiquitous oxidoreductases, which utilize the reducing power of glutathione to reduce disulfide bonds of substrate proteins and maintain cellular redox homeostasis. Here, we report that tomato expressing Arabidopsis GRX gene AtGRXS17 conferred tolerance to chilling stress without adverse effects on growth and development. AtGRXS17-expressing tomato plants displayed lower ion leakage, higher maximal photochemical efficiency of photosystem II (Fv/Fm) and increased accumulation of soluble sugar compared with wild-type plants after the chilling stress challenge. Furthermore, chilling tolerance was correlated with increased antioxidant enzyme activities and reduced H2O2 accumulation. At the same time, temporal expression patterns of the endogenous C-repeat/DRE-binding factor 1 (SlCBF1) and CBF mediated-cold regulated genes were not altered in AtGRXS17-expressing plants when compared with wild-type plants, and proline concentrations remained unchanged relative to wild-type plants under chilling stress. Green fluorescent protein -AtGRXS17 fusion proteins, which were initially localized in the cytoplasm, migrated into the nucleus during chilling stress, reflecting a possible role of AtGRXS17 in nuclear signaling of chilling stress responses. Together, our findings demonstrate that genetically engineered tomato plants expressing AtGRXS17 can enhance chilling tolerance and suggest a genetic engineering strategy to improve chilling tolerance without yield penalty across different crop species.

  2. Tomato expressing Arabidopsis glutaredoxin gene AtGRXS17 confers tolerance to chilling stress via modulating cold responsive components

    PubMed Central

    Hu, Ying; Wu, Qingyu; Sprague, Stuart A; Park, Jungeun; Oh, Myungmin; Rajashekar, C B; Koiwa, Hisashi; Nakata, Paul A; Cheng, Ninghui; Hirschi, Kendal D; White, Frank F; Park, Sunghun

    2015-01-01

    Chilling stress is a production constraint of tomato, a tropical origin, chilling-sensitive horticultural crop. The development of chilling tolerant tomato thus has significant potential to impact tomato production. Glutaredoxins (GRXs) are ubiquitous oxidoreductases, which utilize the reducing power of glutathione to reduce disulfide bonds of substrate proteins and maintain cellular redox homeostasis. Here, we report that tomato expressing Arabidopsis GRX gene AtGRXS17 conferred tolerance to chilling stress without adverse effects on growth and development. AtGRXS17-expressing tomato plants displayed lower ion leakage, higher maximal photochemical efficiency of photosystem II (Fv/Fm) and increased accumulation of soluble sugar compared with wild-type plants after the chilling stress challenge. Furthermore, chilling tolerance was correlated with increased antioxidant enzyme activities and reduced H2O2 accumulation. At the same time, temporal expression patterns of the endogenous C-repeat/DRE-binding factor 1 (SlCBF1) and CBF mediated-cold regulated genes were not altered in AtGRXS17-expressing plants when compared with wild-type plants, and proline concentrations remained unchanged relative to wild-type plants under chilling stress. Green fluorescent protein -AtGRXS17 fusion proteins, which were initially localized in the cytoplasm, migrated into the nucleus during chilling stress, reflecting a possible role of AtGRXS17 in nuclear signaling of chilling stress responses. Together, our findings demonstrate that genetically engineered tomato plants expressing AtGRXS17 can enhance chilling tolerance and suggest a genetic engineering strategy to improve chilling tolerance without yield penalty across different crop species. PMID:26623076

  3. Tomato expressing Arabidopsis glutaredoxin gene AtGRXS17 confers tolerance to chilling stress via modulating cold responsive components.

    PubMed

    Hu, Ying; Wu, Qingyu; Sprague, Stuart A; Park, Jungeun; Oh, Myungmin; Rajashekar, C B; Koiwa, Hisashi; Nakata, Paul A; Cheng, Ninghui; Hirschi, Kendal D; White, Frank F; Park, Sunghun

    2015-01-01

    Chilling stress is a production constraint of tomato, a tropical origin, chilling-sensitive horticultural crop. The development of chilling tolerant tomato thus has significant potential to impact tomato production. Glutaredoxins (GRXs) are ubiquitous oxidoreductases, which utilize the reducing power of glutathione to reduce disulfide bonds of substrate proteins and maintain cellular redox homeostasis. Here, we report that tomato expressing Arabidopsis GRX gene AtGRXS17 conferred tolerance to chilling stress without adverse effects on growth and development. AtGRXS17-expressing tomato plants displayed lower ion leakage, higher maximal photochemical efficiency of photosystem II (Fv/Fm) and increased accumulation of soluble sugar compared with wild-type plants after the chilling stress challenge. Furthermore, chilling tolerance was correlated with increased antioxidant enzyme activities and reduced H2O2 accumulation. At the same time, temporal expression patterns of the endogenous C-repeat/DRE-binding factor 1 (SlCBF1) and CBF mediated-cold regulated genes were not altered in AtGRXS17-expressing plants when compared with wild-type plants, and proline concentrations remained unchanged relative to wild-type plants under chilling stress. Green fluorescent protein -AtGRXS17 fusion proteins, which were initially localized in the cytoplasm, migrated into the nucleus during chilling stress, reflecting a possible role of AtGRXS17 in nuclear signaling of chilling stress responses. Together, our findings demonstrate that genetically engineered tomato plants expressing AtGRXS17 can enhance chilling tolerance and suggest a genetic engineering strategy to improve chilling tolerance without yield penalty across different crop species. PMID:26623076

  4. Climate Change Impact on Evapotranspiration, Heat Stress and Chill Requirements

    NASA Astrophysics Data System (ADS)

    Snyder, R. L.; Marras, S.; Spano, D.

    2013-12-01

    Carbon dioxide concentration scenarios project an increase in CO2 from 372 ppm to between 500 and 950 ppm by the year 2100, and the potential effect on temperature, humidity, and plant responses to environmental factors are complex and concerning. For 2100, mean daily temperature increase projections range from 1.2oC to 6.8oC depending on greenhouse gas emissions. On the bad side, higher temperatures are often associated with increases in evapotranspiration (ET), heat stress, and pest infestations. On the good side, increased temperature is commonly related to less frost damage, faster growth, and higher production in some cases. One misconception is that global warming will increase evapotranspiration and, hence, agricultural water demand. As the oceans and other water bodies warm, evaporation and humidity are likely to increase globally, but higher humidity tends to reduce plant transpiration and hence ET. Higher CO2 concentrations also tend to reduce ET, and, in the end, the increase in ET due to higher temperature is likely to be offset by a decrease in ET due to higher humidity and CO2. With a decrease in daytime evapotranspiration, the canopy temperature is likely to rise relative to the air temperature, and this implies that heat stress could be worse than predicted by increased air temperature. Daily minimum temperatures are generally increasing about twice as fast as maximum temperatures presumably because of the increasing dew point temperatures as more water vapor is added to the atmosphere. This could present a serious problem to meet the chill requirement for fruit and nut crops. Growing seasons, i.e., from the last spring to the first fall frost, are likely to increase, but the crop growth period is likely to shorten due to higher temperature. Thus, spring frost damage is unlikely to change but there should be fewer damaging fall frost events. In this paper, we will present some ideas on the possible impact of climate change on evapotranspiration and

  5. Advanced Lost Foam Casting Technology

    SciTech Connect

    Charles E. Bates; Harry E. Littleton; Don Askeland; Taras Molibog; Jason Hopper; Ben Vatankhah

    2000-11-30

    This report describes the research done under the six tasks to improve the process and make it more functional in an industrial environment. Task 1: Pattern Pyrolysis Products and Pattern Properties Task 2: Coating Quality Control Task 3: Fill and Solidification Code Task 4: Alternate Pattern Materials Task 5: Casting Distortion Task 6: Technology Transfer

  6. Casting Freedom, 1860-1862

    ERIC Educational Resources Information Center

    Social Education, 2005

    2005-01-01

    Thomas Crawford, an American Sculptor, created the full-size figure of Freedom in clay. Molds were made, from which a full-size positive plaster model was cast in five main sections. This model is on view today in the basement rotunda of the Russell Senate Office Building. Clark Mills was a self-taught American sculptor with experience in casting…

  7. Tape casting of magnesium oxide.

    SciTech Connect

    Ayala, Alicia; Corral, Erica L.; Loehman, Ronald E.; Bencoe, Denise Nora; Reiterer, Markus; Shah, Raja A.

    2008-02-01

    A tape casting procedure for fabricating ceramic magnesium oxide tapes has been developed as a method to produce flat sheets of sintered MgO that are thin and porous. Thickness of single layer tapes is in the range of 200-400 {micro}m with corresponding surface roughness values in the range of 10-20 {micro}m as measured by laser profilometry. Development of the tape casting technique required optimization of pretreatment for the starting magnesium oxide (MgO) powder as well as a detailed study of the casting slurry preparation and subsequent heat treatments for sintering and final tape flattening. Milling time of the ceramic powder, plasticizer, and binder mixture was identified as a primary factor affecting surface morphology of the tapes. In general, longer milling times resulted in green tapes with a noticeably smoother surface. This work demonstrates that meticulous control of the entire tape casting operation is necessary to obtain high-quality MgO tapes.

  8. Molding A Cast Metals Program

    ERIC Educational Resources Information Center

    Trumble, Dale E.

    1975-01-01

    The cast metals program, a two-year associate degree program, at Muskegon Community College, Musegon, Michigan operates in close cooperation with the local foundry industry to provide a background for entry-level technical jobs and for continued studies toward a four-year degree. (EA)

  9. Graphite Formation in Cast Iron

    NASA Technical Reports Server (NTRS)

    Stefanescu, D. M.

    1985-01-01

    In the first phase of the project it was proven that by changing the ratio between the thermal gradient and the growth rate for commercial cast iron samples solidifying in a Bridgman type furnace, it is possible to produce all types of graphite structures, from flake to spheroidal, and all types of matrices, from ferritic to white at a certain given level of cerium. KC-135 flight experiments have shown that in a low-gravity environment, no flotation occurs even in spheroidal graphite cast irons with carbon equivalent as high as 5%, while extensive graphite flotation occurred in both flake and spheroidal graphite cast irons, in high carbon samples solidified in a high gravity environment. This opens the way for production of iron-carbon composite materials, with high carbon content (e.g., 10%) in a low gravity environment. By using KC-135 flights, the influence of some basic elements on the solidification of cast iron will be studied. The mechanism of flake to spheroidal graphite transition will be studied, by using quenching experiments at both low and one gravity for different G/R ratios.

  10. Math: Objectives Guide. Project CAST.

    ERIC Educational Resources Information Center

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

    The guide lists math objectives needed for independent living by secondary special education students. One of a series of Project CAST (Community and School Together) life skills manuals, the guide outlines basic competencies in terms of goal statements, behavioral objectives, and specialized vocabulary for the following areas: money, making…

  11. Prediction of Microporosity in Shrouded Impeller Castings

    SciTech Connect

    Viswanathan, S. Nelson, C.D.

    1998-09-01

    The purpose of this Cooperative Research and Development Agreement (CRADA) between the Oak Ridge National Laboratory (ORNL) and Morris Bean and Company was to link computer models of heat and fluid flow with previously developed quality criteria for the prediction of microporosity in a Al-4.5% Cu alloy shrouded impeller casting. The results may be used to analyze the casting process design for the commercial production of 206 o alloy shrouded impeller castings. Test impeller castings were poured in the laboratory for the purpose of obtaining thermal data and porosity distributions. Also, a simulation of the test impeller casting was conducted and the results validated with porosity measurements on the test castings. A comparison of the predicted and measured microporosity distributions indicated an excellent correlation between experiments and prediction. The results of the experimental and modeling studies undertaken in this project indicate that the quality criteria developed for the prediction of microporosity in Al-4.5% Cu alloy castings can accurately predict regions of elevated microporosity even in complex castings such as the shrouded impeller casting. Accordingly, it should be possible to use quality criteria for porosity prediction in conjunction with computer models of heat and fluid flow to optimize the casting process for the production of shrouded impeller castings. Since high levels of microporosity may be expected to result in poor fatigue properties, casting designs that are optimized for low levels of microporosity should exhibit superior fatigue life.

  12. 14 CFR 27.621 - Casting factors.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 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...

  13. 14 CFR 27.621 - Casting factors.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 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...

  14. 14 CFR 29.621 - Casting factors.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 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...

  15. 14 CFR 27.621 - Casting factors.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 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...

  16. 14 CFR 29.621 - Casting factors.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 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...

  17. 14 CFR 29.621 - Casting factors.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 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...

  18. Chimerical categories: caste, race, and genetics.

    PubMed

    Sabir, Sharjeel

    2003-12-01

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

  19. Diabetic Neuropathy: What is a Total Contact Cast?

    MedlinePlus

    ... Web version Diabetic Neuropathy | What is a Total Contact Cast? What is a total contact cast? A total contact cast is a cast used to treat ulcers ( ... foot--that's why it is called a total contact cast. The cast helps to protect the skin ...

  20. Shallow water model for horizontal centrifugal casting

    NASA Astrophysics Data System (ADS)

    Boháček, J.; Kharicha, A.; Ludwig, A.; Wu, M.

    2012-07-01

    A numerical model was proposed to simulate the solidification process of an outer shell of work roll made by the horizontal centrifugal casting technique. Shallow water model was adopted to solve the 2D average flow dynamics of melt spreading and the average temperature distribution inside the centrifugal casting mould by considering the centrifugal force, Coriolis force, viscous force due to zero velocity on the mould wall, gravity, and energy transport by the flow. Additionally, a 1D sub-model was implemented to consider the heat transfer in the radial direction from the solidifying shell to the mould. The solidification front was tracked by fulfilling the Stefan condition. Radiative and convective heat losses were included from both, the free liquid surface and the outer wall of the mould. Several cases were simulated with the following assumed initial conditions: constant height of the liquid metal (10, 20, and 30 mm), uniform temperature of the free liquid surface (1755 K). The simulation results have shown that while the solidification front remained rather flat, the free surface was disturbed by waves. The amplitude of waves increased with the liquid height. Free surface waves diminished as the solidification proceeded.

  1. Prototype casting fabrication by stereolithography

    SciTech Connect

    Cromwell, W.E.

    1990-11-01

    A new product development technology is emerging which could have a major impact on the investment casting industry. It's identified by several names, the most common of which is STEREOLITHOGRAPHY.'' This technology involves a three-dimensional printing process which will yield plastic parts (polymer models) from solid, surface, or wireframe CAD files. The concept links a CAD database to a process which guides a laser beam to solidify liquid photo-curable polymer into a programmed shaped. The process can produce models in far less time and at far less cost than can be done by other known (conventional) model producing methods. Parts that would normally require weeks or months to prototype with conventional processes can be produced in a matter of hours by Stereolithography. The Allied-Signal Inc., Kansas City Division, is engaged in a development project (funded by the Department of Energy) which is aimed at establishing this process as a practical, expedient, and cost-effective method fabricating prototype investment castings. The early phases of the project include procurement of a special designed test unit for several companies (Service Centers) involved in fabrication of models. These models are produced in various materials and used in experimental casting programs being conducted with four casting suppliers (two ferrous and two non-ferrous). This presentation will cover the objectives of the project and the results obtained up to this time. We will also briefly review future plans for the continuation of the project, until this new technology has been proven as a viable process for rapid development of investment castings.

  2. Effect of Putrescine Treatment on Chilling Injury, Fatty Acid Composition and Antioxidant System in Kiwifruit.

    PubMed

    Yang, Qingzhen; Wang, Feng; Rao, Jingping

    2016-01-01

    We investigated the effects of different concentrations (0, 1, 2 and 4 mM) of putrescine on chilling injury, fruit quality, ethylene production rate, fatty acid composition and the antioxidant system of cold-stored kiwifruit (Actinidia chinensis Planch. var. chinensis 'Hongyang'). We achieved a significant decrease in ethylene production, maintained fruit quality and alleviated chilling injury during storage via treatment with 2 mM putrescine. Furthermore, putrescine treatment inhibited increases in superoxide anion production rate and H2O2 concentration, while maintaining higher membrane lipid unsaturation as well as increased activities of superoxide dismutase and catalase. In addition, putrescine treatment enhanced the activities of antioxidant enzymes related to the ascorbate-glutathione cycle while causing higher levels of ascorbic acid and reduced glutathione. Our results suggest that induced tolerance against chilling injury via putrescine treatment in cold-stored kiwifruit may be due to enhanced antioxidant activity, increased unsaturation of membrane lipids, and inhibited ethylene production. PMID:27607076

  3. [The use of "sous vide" technology in the packaging of chilled and ready to serve food].

    PubMed

    Zalewski, S

    1999-01-01

    As chilled precooked dishes show limited to 3-5 days shelf life several additional factors have to be applied to extend it up to 21 or even 42 days as is sometimes allowed for sous vide technology products. Those factors comprise high hygienic standards for raw materials and premises as well as technological steps and parameters that efficiently destroy microbial contamination, and do not allow for recontamination or bacterial growth. Such steps include precooking which also means pasteurisation in high vacuum or anaerobic atmosphere in sealed pouches, blast chilling, low temperature storage parameters as well as high temperature of reheating process and quick serving procedures. Paper specifies parameters for each technological steps and presents microbiological requirements for final products. Sous vide technology allows for good quality and high nutritional value in soups, meats in sauces and stewed vegetables. It is used for individual consumer in chilled "ready to eat" line dishes in supermarkets and supplies such dishes for catering units. PMID:10523935

  4. Optimum Temperature for Storage of Fruit and Vegetables with Reference to Chilling Injury

    NASA Astrophysics Data System (ADS)

    Murata, Takao

    Cold storage is an important technique for preserving fresh fruit and vegetables. Deterioration due to ripening, senescence and microbiological disease can be retarded by storage at optimum temperature being slightly above the freezing point of tissues of fruit and vegetables. However, some fruit and vegetables having their origins in tropical or subtropical regions of the world are subject to chilling injury during transportation, storage and wholesale distribution at low temperature above freezing point, because they are usually sensitive to low temperature in the range of 15&digC to 0°C. This review will focus on the recent informations regarding chilling injury of fruit and vegetables, and summarize the optimum temperature for transportation and storage of fruit and vegetables in relation to chilling injury.

  5. Chilling to zero degrees disrupts pollen formation but not meiotic microtubule arrays in Triticum aestivum L.

    PubMed

    Barton, Deborah A; Cantrill, Laurence C; Law, Andrew M K; Phillips, Collin G; Sutton, Bruce G; Overall, Robyn L

    2014-12-01

    Throughout the wheat-growing regions of Australia, chilling temperatures below 2 °C occur periodically on consecutive nights during the period of floral development in spring wheat (Triticum aestivum L.). In this study, wheat plants showed significant reductions in fertility when exposed to prolonged chilling temperatures in controlled environment experiments. Among the cultivars tested, the Australian cultivars Kite and Hartog had among the lowest levels of seed set due to chilling and their responses were investigated further. The developmental stage at exposure, the chilling temperature and length of exposure all influenced the level of sterility. The early period of booting, and specifically the +4 cm auricle distance class, was the most sensitive and corresponded to meiosis within the anthers. The response of microtubules to chilling during meiosis in Hartog was monitored, but there was little difference between chilled and control plants. Other abnormalities, such as plasmolysis and cytomixis increased in frequency, were associated with death of developing pollen cells, and could contribute to loss of fertility. The potential for an above-zero chilling sensitivity in Australian spring wheat varieties could have implications for exploring the tolerance of wheat flower development to chilling and freezing conditions in the field.

  6. Chilling to zero degrees disrupts pollen formation but not meiotic microtubule arrays in Triticum aestivum L.

    PubMed

    Barton, Deborah A; Cantrill, Laurence C; Law, Andrew M K; Phillips, Collin G; Sutton, Bruce G; Overall, Robyn L

    2014-12-01

    Throughout the wheat-growing regions of Australia, chilling temperatures below 2 °C occur periodically on consecutive nights during the period of floral development in spring wheat (Triticum aestivum L.). In this study, wheat plants showed significant reductions in fertility when exposed to prolonged chilling temperatures in controlled environment experiments. Among the cultivars tested, the Australian cultivars Kite and Hartog had among the lowest levels of seed set due to chilling and their responses were investigated further. The developmental stage at exposure, the chilling temperature and length of exposure all influenced the level of sterility. The early period of booting, and specifically the +4 cm auricle distance class, was the most sensitive and corresponded to meiosis within the anthers. The response of microtubules to chilling during meiosis in Hartog was monitored, but there was little difference between chilled and control plants. Other abnormalities, such as plasmolysis and cytomixis increased in frequency, were associated with death of developing pollen cells, and could contribute to loss of fertility. The potential for an above-zero chilling sensitivity in Australian spring wheat varieties could have implications for exploring the tolerance of wheat flower development to chilling and freezing conditions in the field. PMID:24762030

  7. RNA Expression and Post-Transcriptional Editing Analyses of Cucumber Plastids Reveals Genetic Differences Associated with Chilling Tolerance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tolerance to chilling injury in cucumber (Cucumis sativus L.) is associated with three plastomic single nucleotide polymorphisms (ptSNPs) at bp positions 4,813, 56,561, and 126,349 that are co-inherited. An understanding of the genetic expression of these ptSNPs as a response to chilling is critical...

  8. Prevalence of Salmonella Following Immersion Chilling for Matched Neck Skin, Whole Carcass Rinse, and Whole Carcass Enrichment Sampling Methodologies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella prevalence and the serogroups recovered following immersion chilling were determined for matched enriched neck skin, whole carcass rinse, and whole carcass samples. Commercially processed and eviscerated broiler carcasses were chilled in ice/tap water 40 min with or without 20 ppm free c...

  9. Cold-induced sudden reversible lowering of in vivo chlorophyll fluorescence after saturating light pulses : a sensitive marker for chilling susceptibility.

    PubMed

    Larcher, W; Neuner, G

    1989-03-01

    In chilling-sensitive plants (Glycine max, Saintpaulia ionantha, Saccharum officinarum) a sudden reversible drop in chlorophyll fluorescence occurs during photosynthetic induction immediately following saturating light pulses at low temperatures in the range 4 to 8 degrees C. A comparison of two soybean cultivars of different chilling sensitivities revealed that this phenomenon, termed lowwave, indicates specific thresholds of low temperature stress. Its occurrence under controlled chilling can be regarded as a quantitative marker for screening chilling susceptibility in angiosperms. PMID:16666615

  10. Transcriptome Analysis of Pepper (Capsicum annuum) Revealed a Role of 24-Epibrassinolide in Response to Chilling.

    PubMed

    Li, Jie; Yang, Ping; Kang, Jungen; Gan, Yantai; Yu, Jihua; Calderón-Urrea, Alejandro; Lyu, Jian; Zhang, Guobin; Feng, Zhi; Xie, Jianming

    2016-01-01

    Brassinosteroids (BRs) have positive effects on many processes during plant growth, development, and various abiotic stress responses. However, little information is available regarding the global gene expression of BRs in response to chilling stress in pepper. In this study, we used RNA sequencing to determine the molecular roles of 24-epibrassinolide (EBR) during a chilling stress response. There were 39,829 transcripts, and, among them, 656 were differently-expressed genes (DEGs) following EBR treatment (Chill+EBR) compared with the control (Chill only), including 335 up-regulated and 321 down-regulated DEGs. We selected 20 genes out of the 656 DEGs for RT-qPCR analysis to confirm the RNA-Seq. Based on GO enrich and KEGG pathway analysis, we found that photosynthesis was significantly up-enriched in biological processes, accompanied by significant increases in the net photosynthetic rate (Pn), Fv/Fm, and chlorophyll content. Furthermore, the results indicate that EBR enhanced endogenous levels of salicylic acid (SA) and jasmonic acid (JA) while suppressing the ethylene (ETH) biosynthesis pathway, suggesting that BRs function via a synergistic cross-talk with SA, JA, and ETH signaling pathways in response to chilling stress. In addition, EBR induced cellulose synthase-like protein and UDP-glycosyltransferase, suggesting a contribution to the formation of cell wall and hormone metabolism. EBR also triggered the calcium signaling transduction in cytoplasm, and activated the expression of cellular redox homeostasis related genes, such as GSTX1, PER72, and CAT2. This work, therefor, identified the specific genes showed different expression patterns in EBR-treated pepper and associated with the processes of hormone metabolism, redox, signaling, transcription, and defense. Our study provides the first evidence of the potent roles of BRs, at the transcription level, to induce the tolerance to chilling stress in pepper as a function of the combination of the

  11. Transcriptome Analysis of Pepper (Capsicum annuum) Revealed a Role of 24-Epibrassinolide in Response to Chilling

    PubMed Central

    Li, Jie; Yang, Ping; Kang, Jungen; Gan, Yantai; Yu, Jihua; Calderón-Urrea, Alejandro; Lyu, Jian; Zhang, Guobin; Feng, Zhi; Xie, Jianming

    2016-01-01

    Brassinosteroids (BRs) have positive effects on many processes during plant growth, development, and various abiotic stress responses. However, little information is available regarding the global gene expression of BRs in response to chilling stress in pepper. In this study, we used RNA sequencing to determine the molecular roles of 24-epibrassinolide (EBR) during a chilling stress response. There were 39,829 transcripts, and, among them, 656 were differently-expressed genes (DEGs) following EBR treatment (Chill+EBR) compared with the control (Chill only), including 335 up-regulated and 321 down-regulated DEGs. We selected 20 genes out of the 656 DEGs for RT-qPCR analysis to confirm the RNA-Seq. Based on GO enrich and KEGG pathway analysis, we found that photosynthesis was significantly up-enriched in biological processes, accompanied by significant increases in the net photosynthetic rate (Pn), Fv/Fm, and chlorophyll content. Furthermore, the results indicate that EBR enhanced endogenous levels of salicylic acid (SA) and jasmonic acid (JA) while suppressing the ethylene (ETH) biosynthesis pathway, suggesting that BRs function via a synergistic cross-talk with SA, JA, and ETH signaling pathways in response to chilling stress. In addition, EBR induced cellulose synthase-like protein and UDP-glycosyltransferase, suggesting a contribution to the formation of cell wall and hormone metabolism. EBR also triggered the calcium signaling transduction in cytoplasm, and activated the expression of cellular redox homeostasis related genes, such as GSTX1, PER72, and CAT2. This work, therefor, identified the specific genes showed different expression patterns in EBR-treated pepper and associated with the processes of hormone metabolism, redox, signaling, transcription, and defense. Our study provides the first evidence of the potent roles of BRs, at the transcription level, to induce the tolerance to chilling stress in pepper as a function of the combination of the

  12. The benefits of liposomes for chilling canine sperm for 4 days at 4°C.

    PubMed

    Belala, Redha; Delay, Juliette; Amirat, Lamia; Ropers, Marie-Hélène; Le Guillou, Jocya; Anton, Marc; Schmitt, Eric; Thorin, Chantal; Michaud, Sandrine; Kaidi, Rachid; Tainturier, Daniel; Bencharif, Djemil

    2016-05-01

    This study comprises 3 experiments exploring the possible benefits and mechanism of action of liposomes for chilling (4°C) canine sperm over a period of 4 days. In the first experiment, 20 ejaculates collected from 5 Beagle dogs were chilled in an extender containing 6% low density lipoproteins (LDL) (Control), or one of 7 extenders containing different concentrations (2, 4, 6, 8, 10, 15, 20%) of liposomes (LIPO). These ejaculates were chilled over 4 days and motility was assessed daily using a Hamilton Thorne analyzer (HTM-IVOS, 14.0). The 2% LIPO obtained the best results (p=0.038) after four days (72.55% motile spermatozoa and 31.4% progressive spermatozoa). In experiment 2, 10 ejaculates were collected from same 5 dogs and chilled in 6% LDL or 2% LIPO-based extenders. Sperm integrity characteristics were assessed prior to refrigeration and every 48h for four days (D0, D2, and D4). Acrosome integrity was assessed using the FITC-PSA test (Fluorescein IsoThiocyanate-Pisum Sativum Agglutinin), plasma membrane (PM) integrity using both the hypo-osmotic swelling test (HOSt) and SYBR14/Propidium Iodide test (SYBR14/PI), and DNA integrity using the Acridine-Orange test (AO). The 2% LIPO extender provided equivalent preservation of sperm integrity parameters to the reference extender (6% LDL). In experiment 3, a Langmuir-Blodgett trough was used to evaluate the mechanistic interactions between LDL, LIPO, prostatic fluid, and the canine spermatozoal membrane during chilling. Results indicate that LDL and LIPO interact differently with the biomimetic membrane. The most likely conclusion of these findings is that LDL and liposomes employ different protective mechanisms during the chilling (4°C) of canine spermatozoa.

  13. The benefits of liposomes for chilling canine sperm for 4 days at 4°C.

    PubMed

    Belala, Redha; Delay, Juliette; Amirat, Lamia; Ropers, Marie-Hélène; Le Guillou, Jocya; Anton, Marc; Schmitt, Eric; Thorin, Chantal; Michaud, Sandrine; Kaidi, Rachid; Tainturier, Daniel; Bencharif, Djemil

    2016-05-01

    This study comprises 3 experiments exploring the possible benefits and mechanism of action of liposomes for chilling (4°C) canine sperm over a period of 4 days. In the first experiment, 20 ejaculates collected from 5 Beagle dogs were chilled in an extender containing 6% low density lipoproteins (LDL) (Control), or one of 7 extenders containing different concentrations (2, 4, 6, 8, 10, 15, 20%) of liposomes (LIPO). These ejaculates were chilled over 4 days and motility was assessed daily using a Hamilton Thorne analyzer (HTM-IVOS, 14.0). The 2% LIPO obtained the best results (p=0.038) after four days (72.55% motile spermatozoa and 31.4% progressive spermatozoa). In experiment 2, 10 ejaculates were collected from same 5 dogs and chilled in 6% LDL or 2% LIPO-based extenders. Sperm integrity characteristics were assessed prior to refrigeration and every 48h for four days (D0, D2, and D4). Acrosome integrity was assessed using the FITC-PSA test (Fluorescein IsoThiocyanate-Pisum Sativum Agglutinin), plasma membrane (PM) integrity using both the hypo-osmotic swelling test (HOSt) and SYBR14/Propidium Iodide test (SYBR14/PI), and DNA integrity using the Acridine-Orange test (AO). The 2% LIPO extender provided equivalent preservation of sperm integrity parameters to the reference extender (6% LDL). In experiment 3, a Langmuir-Blodgett trough was used to evaluate the mechanistic interactions between LDL, LIPO, prostatic fluid, and the canine spermatozoal membrane during chilling. Results indicate that LDL and LIPO interact differently with the biomimetic membrane. The most likely conclusion of these findings is that LDL and liposomes employ different protective mechanisms during the chilling (4°C) of canine spermatozoa. PMID:26952759

  14. Overexpression of glycerol-3-phosphate acyltransferase gene improves chilling tolerance in tomato.

    PubMed

    Sui, Na; Li, Meng; Zhao, Shi-Jie; Li, Feng; Liang, Hui; Meng, Qing-Wei

    2007-10-01

    A tomato (Lycopersicon esculentum Mill.) glycerol-3-phosphate acyltransferase gene (LeGPAT) was isolated. The deduced amino acid sequence revealed that LeGPAT contained four acyltransferase domains, showing high identities with GPAT in other plant species. A GFP fusion protein of LeGPAT was targeted to chloroplast in cowpea mesophyll protoplast. RNA gel blot showed that the mRNA accumulation of LeGPAT in the wild type (WT) was induced by chilling temperature. Higher expression levels were observed when tomato leaves were exposed to 4 degrees C for 4 h. RNA gel and western blot analysis confirmed that the sense gene LeGPAT was transferred into the tomato genome and overexpressed under the control of 35S-CaMV. Although tomato is classified as a chilling-sensitive plant, LeGPAT exhibited selectivity to 18:1 over 16:0. Overexpression of LeGPAT increased total activity of LeGPAT and cis-unsaturated fatty acids in PG in thylakoid membrane. Chilling treatment induced less ion leakage from the transgenic plants than from the WT. The photosynthetic rate and the maximal photochemical efficiency of PS II (Fv/Fm) in transgenic plants decreased more slowly during chilling stress and recovered faster than in WT under optimal conditions. The oxidizable P700 in both WT and transgenic plants decreased obviously at chilling temperature under low irradiance, but the oxidizable P700 recovered faster in transgenic plants than in the WT. These results indicate that overexpression of LeGPAT increased the levels of PG cis-unsaturated fatty acids in thylakoid membrane, which was beneficial for the recovery of chilling-induced PS I photoinhibition in tomato.

  15. Transcriptome Analysis of Pepper (Capsicum annuum) Revealed a Role of 24-Epibrassinolide in Response to Chilling

    PubMed Central

    Li, Jie; Yang, Ping; Kang, Jungen; Gan, Yantai; Yu, Jihua; Calderón-Urrea, Alejandro; Lyu, Jian; Zhang, Guobin; Feng, Zhi; Xie, Jianming

    2016-01-01

    Brassinosteroids (BRs) have positive effects on many processes during plant growth, development, and various abiotic stress responses. However, little information is available regarding the global gene expression of BRs in response to chilling stress in pepper. In this study, we used RNA sequencing to determine the molecular roles of 24-epibrassinolide (EBR) during a chilling stress response. There were 39,829 transcripts, and, among them, 656 were differently-expressed genes (DEGs) following EBR treatment (Chill+EBR) compared with the control (Chill only), including 335 up-regulated and 321 down-regulated DEGs. We selected 20 genes out of the 656 DEGs for RT-qPCR analysis to confirm the RNA-Seq. Based on GO enrich and KEGG pathway analysis, we found that photosynthesis was significantly up-enriched in biological processes, accompanied by significant increases in the net photosynthetic rate (Pn), Fv/Fm, and chlorophyll content. Furthermore, the results indicate that EBR enhanced endogenous levels of salicylic acid (SA) and jasmonic acid (JA) while suppressing the ethylene (ETH) biosynthesis pathway, suggesting that BRs function via a synergistic cross-talk with SA, JA, and ETH signaling pathways in response to chilling stress. In addition, EBR induced cellulose synthase-like protein and UDP-glycosyltransferase, suggesting a contribution to the formation of cell wall and hormone metabolism. EBR also triggered the calcium signaling transduction in cytoplasm, and activated the expression of cellular redox homeostasis related genes, such as GSTX1, PER72, and CAT2. This work, therefor, identified the specific genes showed different expression patterns in EBR-treated pepper and associated with the processes of hormone metabolism, redox, signaling, transcription, and defense. Our study provides the first evidence of the potent roles of BRs, at the transcription level, to induce the tolerance to chilling stress in pepper as a function of the combination of the

  16. Hydrogen peroxide is involved in the cold acclimation-induced chilling tolerance of tomato plants.

    PubMed

    Zhou, Jie; Wang, Jian; Shi, Kai; Xia, Xiao Jian; Zhou, Yan Hong; Yu, Jing Quan

    2012-11-01

    Cold acclimation increases plant tolerance to a more-severe chilling and in this process an accumulation of H(2)O(2) in plants is often observed. To examine the role of H(2)O(2) in cold acclimation in plants, the accumulation of H(2)O(2), antioxidant metabolism, the glutathione redox state, gas exchange and chlorophyll fluorescence were analyzed after cold acclimation at 12/10 °C and during the subsequent chilling at 7/4 °C in tomato (Solanum lycopersicum) plants. Cold acclimation modestly elevated the levels of H(2)O(2), the gene expression of respiratory burst oxidase homolog 1 (Rboh1) and NADPH oxidase activity, leading to the up-regulation of the expression and activity of antioxidant enzymes. In non-acclimated plants chilling caused a continuous rise in the H(2)O(2) content, an increase in the malondialdehyde (MDA) content and in the oxidized redox state of glutathione, followed by reductions in the CO(2) assimilation rate and the maximum quantum yield of photosystem II (F(v)/F(m)). However, in cold-acclimated plants chilling-induced photoinhibition, membrane peroxidation and reductions in the CO(2) assimilation rate were significantly alleviated. Furthermore, a treatment with an NADPH oxidase inhibitor or H(2)O(2) scavenger before the plants subjected to the cold acclimation abolished the cold acclimation-induced beneficial effects on photosynthesis and antioxidant metabolism, leading to a loss of the cold acclimation-induced tolerance against chilling. These results strongly suggest that the H(2)O(2) generated by NADPH oxidase in the apoplast of plant cells plays a crucial role in cold acclimation-induced chilling tolerance.

  17. Salicylic acid and methyl jasmonate improve chilling tolerance in cold-stored lemon fruit (Citrus limon).

    PubMed

    Siboza, Xolani Irvin; Bertling, Isa; Odindo, Alfred Oduor

    2014-11-15

    Chilling injury (CI) is associated with the degradation of membrane integrity which can be aligned to phenolic oxidation activated by polyphenol oxidase (PPO) and peroxidase (POD), enzymes responsible for tissue browning. Phenylalanine ammonia-lyase (PAL) is a further enzyme prominent in the phenolic metabolism that is involved in acclimation against chilling stress. It was hypothesized that treatment with methyl jasmonate (MJ) and salicylic acid (SA) may enhance chilling tolerance in lemon fruit by increasing the synthesis of total phenolics and PAL by activating the key enzyme regulating the shikimic acid pathway whilst inhibiting the activity of POD and PPO. Lemon fruit were treated with 10μM MJ, 2mM SA or 10μM MJ plus 2mM SA, waxed, stored at -0.5, 2 or 4.5°C for up to 28 days plus 7 days at 23°C. Membrane integrity was studied by investigating membrane permeability and the degree of membrane lipid peroxidation in lemon flavedo following cold storage. The 10μM MJ plus 2mM SA treatment was most effective in enhancing chilling tolerance of lemon fruit, significantly reducing chilling-induced membrane permeability and membrane lipid peroxidation of lemon flavedo tissue. This treatment also increased total phenolics and PAL activity in such tissue while inhibiting POD activity, the latter possibly contributing to the delay of CI manifestation. PPO activity was found to be a poor biochemical marker of CI. Treatment with 10μM MJ plus 2mM SA resulted in an alteration of the phenolic metabolism, enhancing chilling tolerance, possibly through increased production of total phenolics and the activation of PAL and inhibition of POD.

  18. Cook-chill, cook-freeze, cook-hold, sous vide: risks for hospital patients?

    PubMed

    Wilkinson, P J; Dart, S P; Hadlington, C J

    1991-06-01

    Changes in eating habits and developments in food technology are occurring at the same time as an upward trend in foodborne infection in Britain. Vulnerable people such as the elderly and hospital patients are increasingly likely to consume food produced by new systems such as 'cook-chill' and 'cuisson sous vide'. The microbiological hazards of these systems are assessed as negligible, provided that production is controlled by appropriate methods such as the hazard analysis critical control point (HACCP) approach. The occurrence and control of bacterial contamination in a hospital cook-chill system is reviewed in this context. PMID:1679787

  19. Cook-chill, cook-freeze, cook-hold, sous vide: risks for hospital patients?

    PubMed

    Wilkinson, P J; Dart, S P; Hadlington, C J

    1991-06-01

    Changes in eating habits and developments in food technology are occurring at the same time as an upward trend in foodborne infection in Britain. Vulnerable people such as the elderly and hospital patients are increasingly likely to consume food produced by new systems such as 'cook-chill' and 'cuisson sous vide'. The microbiological hazards of these systems are assessed as negligible, provided that production is controlled by appropriate methods such as the hazard analysis critical control point (HACCP) approach. The occurrence and control of bacterial contamination in a hospital cook-chill system is reviewed in this context.

  20. Effect of irradiation and storage time on lipid oxidation of chilled pork

    NASA Astrophysics Data System (ADS)

    Cheng, Anwei; Wan, Fachun; Xu, Tongcheng; Du, Fangling; Wang, Wenliang; Zhu, Qingjun

    2011-03-01

    The effects of γ-irradiation with different doses (0, 2, 4, 6, 8 and 10 kGy) and storage time (0-30 days) on the lipid oxidation of chilled pork and the combined effect of irradiation and antioxidant on the lipid oxidative stability during storage at 4 °C were investigated. The results indicated that irradiation treatment increased lipid oxidation, measured as peroxide (PV) and thiobarbituric acid reactive substance (TBARS) values. Lipid oxidation was increased with the increase in storage time. The addition of tea polyphenol (TP) was effective in controlling the lipid oxidation of chilled pork after irradiation during cold storage.

  1. WTEC panel report on advanced casting technologies in Japan and Europe

    SciTech Connect

    Flemings, M.C.; Apelian, D.; Bertram, D.; Hayden, W.; Mikkola, P.H.; Piwonka, T.S.

    1997-03-01

    This report presents the results and conclusions from a study of the Japanese foundry industry conducted by a WTEC study team in January 1996. Results of that study were supplemented by additional visits later in the spring to foundries and foundry laboratories in Europe. During its week in Japan, subgroups of the team visited 22 facilities. Included in these were four metal mold foundries, five iron and steel (sand mold) foundries, four investment casting foundries, four industrial research laboratories, four universities, and one government office. In Chapter 2, Melting and Handling, Diran Apelian discusses what he considers the most critical components in the overall metal casting operation: the melting of the metal and the process of liquid metal handling. Chapter 3 written by H.W. Hayden, reports findings on active R and D efforts in the Japanese casting companies directed to the development of new cast alloys and materials, new ceramic and cermet materials for application by the foundry industry, and major new process/product developments such as amorphous metals and magnetohydrodynamic (MHD) effects on the continuous casting of steel rolling ingots. The next chapter, Metal Mold Casting by Diran Apelian, discusses casting technologies in which the mold cavity is made of a metallic material. The fifth chapter, Japanese and European New Cast Product Development by Paul H. Mikkola, reports findings on new cast products being developed in both Japan and Europe. In Chapter 6, Specialized Sand Casting Technologies, Thomas S. Piwonka assesses the current state of innovation in the field of sand casting in Japan and Europe. In Chapter 7, Current Investment Casting Technology, Thomas S. Piwonka looks at the US precision investment casting industry, which developed during the Second World War. Chapter 8 by Dennis Bertram, assesses the state of manufacturing in Japan: how the Japanese use foundry processes, specialized equipment, alloys, human resources, and the

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

    PubMed

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

    2012-01-01

    The aim of the present study was to evaluate the tensile strength, elongation, microhardness, microstructure and fracture pattern of various metal ceramic alloys cast under different casting conditions. Two Ni-Cr alloys, Co-Cr and Pd-Ag were used. The casting conditions were as follows: electromagnetic induction under argon atmosphere, vacuum, using blowtorch without atmosphere control. For each condition, 16 specimens, each measuring 25 mm long and 2.5 mm in diameter, were obtained. Ultimate tensile strength (UTS) and elongation (EL) tests were performed using a Kratos machine. Vickers Microhardness (VM), fracture mode and microstructure were analyzed by SEM. UTS, EL and VM data were statistically analyzed using ANOVA. For UTS, alloy composition had a direct influence on casting condition of alloys (Wiron 99 and Remanium CD), with higher values shown when cast with Flame/Air (p < 0.05). The factors 'alloy" and 'casting condition" influenced the EL and VM results, generally presenting opposite results, i.e., alloy with high elongation value had lower hardness (Wiron 99), and casting condition with the lowest EL values had the highest VM values (blowtorch). Both factors had significant influence on the properties evaluated, and prosthetic laboratories should select the appropriate casting method for each alloy composition to obtain the desired property. PMID:22641437

  3. Prediction of Part Distortion in Die Casting

    SciTech Connect

    R. Allen Miller

    2005-03-30

    The die casting process is one of the net shape manufacturing techniques and is widely used to produce high production castings with tight tolerances for many industries. An understanding of the stress distribution and the deformation pattern of parts produced by die casting will result in less deviation from the part design specification, a better die design and eventually more productivity and cost savings. This report presents methods that can be used to simulate the die casting process in order to predict the deformation and stresses in the produced part and assesses the degree to which distortion modeling is practical for die casting at the current time. A coupled thermal-mechanical finite elements model was used to simulate the die casting process. The simulation models the effect of thermal and mechanical interaction between the casting and the die. It also includes the temperature dependant material properties of the casting. Based on a designed experiment, a sensitivity analysis was conducted on the model to investigate the effect of key factors. These factors include the casting material model, material properties and thermal interaction between casting and dies. To verify the casting distortion predictions, it was compared against the measured dimensions of produced parts. The comparison included dimensions along and across the parting plane and the flatness of one surface.

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

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

    equations that characterize membrane formation. NASA's Parabolic Flight Research Aircraft provides a small window of low-g (approximately 25 s) that can be used to study macrovoid development in both wet- and dry-cast membranes if an appropriate casting apparatus is used. This casting apparatus should be able to cast the membrane in both low- and high-g in a manner so that essential one-dimensional mass transfer conditions are achieved to insure lateral uniformity in the membrane. The apparatus used in previous research on membrane casting in low-gravity was operated with the plunger driven mechanism. The spring-loaded plunger pushes the bottom block containing the polymer casting solution well directly under the absorbent chamber located in the upper stationary block. However, membranes made via this casting apparatus often displayed lateral nonuniformities that precluded obtaining quantitative information on the macrovoid growth process. Thus, it was necessary to determine the reason for these structural irregularities observed in the low-g casting apparatus. Both experimental as well as computer simulation studies of the low-g casting apparatus established that the impulsive action of the plunger caused the undesired structural nonuniformities. The simulation results showed that the width-to-depth aspect ratio of the shallow well that contains the casting solution in this apparatus was not an important factor in minimizing this problem. Even for a 40:1 (width : depth) aspect ratio, any convection induced by the horizontal motion of the interface of the casting solution will be damped out within 6.25x10(exp 4) seconds. However, the experimental studies revealed that the impulsive motion of the plunger caused a 'sloshing' of the casting solution that had to be eliminated. Therefore, the plungerdriven mechanism was changed to a cam-driven mechanism that did not cause any impulsive motion of the casting solution. Other refinements to this new membrane-casting apparatus

  5. Pressure rig for repetitive casting

    SciTech Connect

    Vasquez, P.; Hutto, W.R.; Philips, A.R.

    1989-09-12

    This patent describes a pressure rig for repetitive casting. It comprises: a hollow ceramic inner shell: an outer steel housing disposed around the outside of the ceramic inner shell. The housing having a pressure end at the lower end thereof and a mold end at the upper end thereof; a rubber diaphragm attached to the pressure end of the outer steel housing; a slideable transit plate located above the rubber diaphragm; a layer of blanket insulating material lining the remaining portion of the hollow ceramic inner shell, thereby defining an inner cavity wherein a casing material is located; a pressure means located at the lower end of the pressure rig for applying pressure to the lower end of the rubber diaphragm; whereby the casting material in the inner cavity is forced out of the pressure rig into a mold when pressure is applied to the lower end of the rubber diaphragm.

  6. Search for chameleons with CAST

    NASA Astrophysics Data System (ADS)

    Anastassopoulos, V.; Arik, M.; Aune, S.; Barth, K.; Belov, A.; Bräuninger, H.; Cantatore, G.; Carmona, J. M.; Cetin, S. A.; Christensen, F.; Collar, J. I.; Dafni, T.; Davenport, M.; Desch, K.; Dermenev, A.; Eleftheriadis, C.; Fanourakis, G.; Ferrer-Ribas, E.; Friedrich, P.; Galán, J.; García, J. A.; Gardikiotis, A.; Garza, J. G.; Gazis, E. N.; Geralis, T.; Giomataris, I.; Hailey, C.; Haug, F.; Hasinoff, M. D.; Hoffmann, D. H. H.; Iguaz, F. J.; Irastorza, I. G.; Jacoby, J.; Jakobsen, A.; Jakovčić, K.; Kaminski, J.; Karuza, M.; Kavuk, M.; Krčmar, M.; Krieger, C.; Krüger, A.; Lakić, B.; Laurent, J. M.; Liolios, A.; Ljubičić, A.; Luzón, G.; Neff, S.; Ortega, I.; Papaevangelou, T.; Pivovaroff, M. J.; Raffelt, G.; Riege, H.; Rosu, M.; Ruz, J.; Savvidis, I.; Solanki, S. K.; Vafeiadis, T.; Villar, J. A.; Vogel, J. K.; Yildiz, S. C.; Zioutas, K.; Brax, P.; Lavrentyev, I.; Upadhye, A.

    2015-10-01

    In this work we present a search for (solar) chameleons with the CERN Axion Solar Telescope (CAST). This novel experimental technique, in the field of dark energy research, exploits both the chameleon coupling to matter (βm) and to photons (βγ) via the Primakoff effect. By reducing the X-ray detection energy threshold used for axions from 1 keV to 400 eV CAST became sensitive to the converted solar chameleon spectrum which peaks around 600 eV. Even though we have not observed any excess above background, we can provide a 95% C.L. limit for the coupling strength of chameleons to photons of βγ ≲1011 for 1 <βm <106.

  7. Pressure rig for repetitive casting

    NASA Technical Reports Server (NTRS)

    Vasquez, Peter (Inventor); Hutto, William R. (Inventor); Philips, Albert R. (Inventor)

    1989-01-01

    The invention is a pressure rig for repetitive casting of metal. The pressure rig performs like a piston for feeding molten metal into a mold. Pressure is applied to an expandable rubber diaphragm which expands like a balloon to force the metal into the mold. A ceramic cavity which holds molten metal is lined with blanket-type insulating material, necessitating only a relining for subsequent use and eliminating the lengthy cavity preparation inherent in previous rigs. In addition, the expandable rubber diaphragm is protected by the insulating material thereby decreasing its vulnerability to heat damage. As a result of the improved design the life expectancy of the pressure rig contemplated by the present invention is more than doubled. Moreover, the improved heat protection has allowed the casting of brass and other alloys with higher melting temperatures than possible in the conventional pressure rigs.

  8. Focused rigidity casts: an overview.

    PubMed

    Dagg, A R; Chockalingam, N; Branthwaite, H

    2013-02-01

    Focused rigidity casts (FRCs) are a novel treatment made from polymer semi-flexible cast material, used in the management of plantar foot ulceration to offload the site of ulceration. Current anecdotal evidence suggests that use of FRCs helps achieve quicker healing time. While FRCs were first used in the treatment of fractures, previous reports suggest that the FRC may be effective in the treatment of plantar foot ulceration. Although there is a paucity of evidence to support the use of FRCs in the treatment of foot ulceration, current evidence demonstrates a decrease in both wound healing time and plantar pressure. The aim of the paper is to examine the importance of offloading plantar ulcerations and introduce FRCs.

  9. Development and optimization of novel sensors for inline measurement of sand filling and compaction stages in lost foam casting

    NASA Astrophysics Data System (ADS)

    Whelan, Matthew J.; Janoyan, Kerop D.

    2005-05-01

    The lost foam casting (LFC), or expendable pattern casting, process is employed worldwide in foundries as an efficient casting technology that offers the advantages of consolidation of components, reduced machining, and recirculation of casting mold material. Currently, many foundries develop a schedule of sand raining flow rates and flask excitation accelerations for each specific pattern through an often-lengthy trial and error procedure. During casting, a single flask acceleration measurement is typically the only measurement by which the sand compaction is monitored. The current research focuses on developing an array of measurement tools to be used in measuring parameters critical to the sand compaction stage of the lost foam casting process to aid in the development of filling and vibration schedules as well as to provide additional inline measurements during foundry operation. In particular, the study focuses on the use of minimally intrusive transducers placed inline to provide direct feedback that can be then used in both passive and active process control.

  10. Comparison of air and immersion chilling on meat quality and shelf life of marinated broiler breast fillets.

    PubMed

    Carroll, C D; Alvarado, C Z

    2008-02-01

    Marinated broiler breast fillets were evaluated using both air- and immersion-chilling treatments. Ninety fillets from air-chilled broiler carcasses and 90 fillets from immersion-chilled broiler carcasses were obtained from a processor to determine differences in meat quality, sensory, and shelf life. At 24 h postmortem, the fillets were vacuum-tumbled (25 in Hg, 30 min, 14 rpm, 4 degrees C) in 2 replications per treatment with a 20% solution (wt/wt) yielding 0.70% NaCl and 0.45% sodium tripolyphosphate in the final product. One-third of the fillets in each replication were packaged in a tray covered with plastic wrap and stored in retail cases to simulate retail shelf-life conditions. The remaining fillets were stored at 4 degrees C for 24 h until analysis for marinade retention, cook loss, consumer evaluation, and objective tenderness. The immersion-chilled fillets had a significantly lower pH (5.56) and were lighter (L* 54.73) when compared with the air-chilled fillets (5.64, L* 50.13, respectively). The air-chilled fillets had a significantly higher marinade pickup (15.51%) than the immersion-chilled (14.07%) fillets. However, there were no significant differences in cook loss percentage in either treatment (approximately 20.03). Shear value was significantly higher in the immersion-chilled fillets (4.14 N), indicating less tender meat than the air-chilled fillets (3.62 N). In the consumer analyses, the air-chilled fillets were significantly different. Of the respondents that noted differences, 19% indicated differences in texture, and 9.67% indicated taste differences. The air-chilled treatment had significantly lower aerobic plate count in postpackaging d 0, 3, and 9. Also, coliforms were significantly lower in the air-chilled treatment through d 6. Therefore, air chilling carcasses may improve color, marination yield, tenderness, and increase the shelf life of retail-packaged broiler breast fillets.

  11. Anisotropic constitutive model and FE simulation of the sintering process of slip cast traditional porcelain

    NASA Astrophysics Data System (ADS)

    Sarbandi, B.; Besson, J.; Boussuge, M.; Ryckelynck, D.

    2010-06-01

    Slip cast ceramic components undergo both sintering shrinkage and creep deformation caused by gravity during the firing cycle. In addition sintering may be anisotropic due to the development of preferential directions during slip casting. Both phenomena induce complex deformations of parts which make the design of casting molds difficult. To help solving this problem, anisotropic constitutive equations are proposed to represent the behavior of the ceramic compacts during sintering. The model parameters are identified using tests allowing to characterize both sintering and creep. The model was implemented in a finite element software and used to simulate the deformation of a traditional ceramic object during sintering.

  12. Anisotropic constitutive model and FE simulation of the sintering process of slip cast traditional porcelain

    SciTech Connect

    Sarbandi, B.; Besson, J.; Boussuge, M.; Ryckelynck, D.

    2010-06-15

    Slip cast ceramic components undergo both sintering shrinkage and creep deformation caused by gravity during the firing cycle. In addition sintering may be anisotropic due to the development of preferential directions during slip casting. Both phenomena induce complex deformations of parts which make the design of casting molds difficult. To help solving this problem, anisotropic constitutive equations are proposed to represent the behavior of the ceramic compacts during sintering. The model parameters are identified using tests allowing to characterize both sintering and creep. The model was implemented in a finite element software and used to simulate the deformation of a traditional ceramic object during sintering.

  13. Feasibility of producing cast-refractory metal-fiber superalloy composites

    NASA Technical Reports Server (NTRS)

    Mcintyre, R. D.

    1973-01-01

    A study was conducted to evaluate the feasibility of direct casting as a practical method for producing cast superalloy tungsten or columbium alloy fiber composites while retaining a high percentage of fiber strength. Fourteen nickel base, four cobalt, and three iron based matrices were surveyed for their degree of reaction with the metal fibers. Some stress-rupture results were obtained at temperatures of 760, 816, 871, and 1093 C for a few composite systems. The feasibility of producing acceptable composites of some cast nickel, cobalt, and iron matrix alloys with tungsten or columbium alloy fibers was demonstrated.

  14. "Chilled" pork--Part I: Sensory and physico-chemical quality.

    PubMed

    Ngapo, T M; Riendeau, L; Laberge, C; Leblanc, D; Fortin, J

    2012-12-01

    Chilled meat exportation comprises chilling within 48 h post-mortem to temperatures <0 °C without freezing and holding under these conditions for several weeks. The effects of this ageing on sensory quality of pork are unknown and hence the objective of this study was to compare the sensory quality of Canadian pork as found in an export (Japan) market and locally. Regardless that the Japanese market's quality criteria were met, pork sorted on-line differed (P<0.05) from that for the domestic market only for lightness, exudate and cooking loss; no differences in intramuscular fat content were observed. Overall, a trained panel scored weaker pork and meat flavours and odours in the export than the domestic pork as a result of either the quality by selection if roasted or the ageing (-1.7 °C, 43 days exported chilled or 3.1 °C, 5 days domestic) if grilled or shabu shabu. Grilled pork was also more tender, sweeter and had stronger caramel flavour with the chilled ageing. PMID:22633163

  15. 9 CFR 327.21 - Inspection procedures for chilled fresh and frozen boneless manufacturing meat.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... fresh and frozen boneless manufacturing meat. 327.21 Section 327.21 Animals and Animal Products FOOD....21 Inspection procedures for chilled fresh and frozen boneless manufacturing meat. (a) Definitions; sampling; standards. (1) Frozen boneless manufacturing meat is meat, frozen in the fresh state from...

  16. 9 CFR 327.21 - Inspection procedures for chilled fresh and frozen boneless manufacturing meat.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... fresh and frozen boneless manufacturing meat. 327.21 Section 327.21 Animals and Animal Products FOOD....21 Inspection procedures for chilled fresh and frozen boneless manufacturing meat. (a) Definitions; sampling; standards. (1) Frozen boneless manufacturing meat is meat, frozen in the fresh state from...

  17. 9 CFR 327.21 - Inspection procedures for chilled fresh and frozen boneless manufacturing meat.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... fresh and frozen boneless manufacturing meat. 327.21 Section 327.21 Animals and Animal Products FOOD....21 Inspection procedures for chilled fresh and frozen boneless manufacturing meat. (a) Definitions; sampling; standards. (1) Frozen boneless manufacturing meat is meat, frozen in the fresh state from...

  18. Optimizing the Design of Chilled Water Plants in Large Commercial Buildings

    NASA Astrophysics Data System (ADS)

    Freeland, Dante'E.

    The design of chilled water plants has a very large impact on building energy use and energy operating costs. This thesis proposes procedures and analysis techniques for energy efficiency design of chilled water plants. The approach that leads to optimal design variables can achieve a significant saving in cooling cost. The optimal variables include piping sizing, chilled water temperature difference, and chilled water supply temperature. The objective function is the total cooling energy cost. The proposed design method depends on detailed cooling load analysis, head and energy calculations, and an optimization solver. The pump head calculations including piping, all fittings, valves, and devices are achieved by using the Darcy-Weisbach Equation and given flow parameters. The energy calculations are done by using generic chiller, fan, and pump models. The method is tested on an existing four-story building located in Greensboro, NC, equipped with a packaged water-cooled chiller. A whole building energy simulation model is used to generate the hourly cooling loads and then the optimal design variables are found to minimize the total energy cost. The testing results show this approach will achieve better results than rules-of-thumb or traditional design procedures. The cooling energy saving could be up to 10% depending on particular projects.

  19. Umami and related components in "chilled" pork for the Japanese market.

    PubMed

    Ngapo, T M; Vachon, L

    2016-11-01

    The aim of this study was to evaluate umami-related components and their evolution in Canadian pork destined for the Japanese market. Export quality pork loins for Japan were subjectively selected on-line for marbling, colour and firmness; remaining loins were retained for the domestic market. At 48h post-mortem, samples were aged 5d at 4.0°C (fresh) or 13, 28, 43 or 58d at -1.7°C (chilled). Meat qualities differed only in pH (<0.1 pH unit; P<0.05). Generally, free amino acid concentrations increased and nucleotide concentrations decreased with longer ageing periods. The equivalent umami concentration (EUC) was highest in the pork aged 5d at 4.0°C and at 43d -1.7°C (P<0.05) which is estimated as the transportation time for Canadian chilled exports to Japan. A lack of differences in EUC between domestic and export pork and between fresh and 43d chilled ageing demonstrates that Canadian chilled pork in Japan has the EUC of its fresh 5d counterpart. PMID:27424307

  20. Can chilling tolerance of C4 photosynthesis in Miscanthus be transferred to sugarcane?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The goal of this study was to investigate if chilling tolerance of C4 photosynthesis in Miscanthus can be transferred to sugarcane. Net leaf CO2 uptake (Asat) and the maximum operating efficiency of photosystem II ('PSII) were measured in warm conditions (25 °C/20 °C), and then during and following ...