Follow-on Research Activities for the Rensselaer Isothermal Dendritic Growth Experiment View Homepage


Ontology type: schema:MonetaryGrant     


Grant Info

YEARS

2000-2004

FUNDING AMOUNT

N/A

ABSTRACT

Kinetics of Melting in Microgravity The kinetics of melting pivalic acid (PVA) dendrites was observed under convection-free conditions on STS-87 as part of the United States Microgravity Payload Mission (USMP-4) flown on Columbia in 1997. Analysis of video data show that PVA dendrites melt without relative motion with respect to the quiescent melt phase. Dendritic fragments display shrinking to extinction, with fragmentation occurring at higher initial supercoolings. The microgravity melting kinetics against which the experimental observations are compared is based on conduction-limited quasi-static melting under shape-preserving conditions. Agreement between analytic theory and our experiments is found when the melting process occurs under shape-preserving conditions as measured using the C/A ratio of individual needle-like crystal fragments. Video data from USMP-4 have been analyzed to establish the rate of melting of individual crystallites in the dendritic mushy zone. The analysis uses potential theoretic methods to calculate analytic descriptions of the thermal field surrounding a prolate spheroidal crystal of PVA subject to melting. The new analysis (Glicksman et al., 2003) is the first that describes quasi-static melting under convection-free conditions. Direct comparison between the video data and the analytical predictions shows excellent correspondence. The IDGE data provided a unique opportunity to observe melting of dendrites without the complications of sedimentation or buoyancy-induced convection. Mushy Zones Evolution We analyzed two PVA crystals melting in microgravity, each formed originally as dendrite created in separate IDGE growth cycles. These dendrites grew from pure molten pivalic acid that was supercooled. The mushy zones consisted of approximately 4\% solid when melting was initiated. The time needed to melt this mushy zone completely was approximately 12 minutes. The last large fragments to melt were selected for quantitative analysis. These fragments had initial lengths of C0=0.760cm and 0.695cm, respectively. To calculate the melting kinetics of these fragments one requires the C/A ratio, the thermal diffusivity of the melt, and the Stefan number imposed by the melting cycle. The thermistors arranged within the IDGE thermostat were optimized for measuring the supercooling prior to dendritic growth quite precisely (±0.002K). The subsequent temperature history within the growth chamber, especially during the melting portion of an experimental growth cycle, is, unfortunately, less certain, because temperature uncertainties arose from the lack of synchronization between the video clock and the mission clock. In view of this situation, one may instead adopt a self-consistent method of estimating the Stefan number in the melt during each melting sequence. The basis of the value of the self-consistent Stefan number is found from the C/A ratio (which equaled 12 for the entire melt cycle), the inital length, C0=0.760, and the length C(t) at a later time t where the fragment has decreased due to melting. In this instance the process of melting was followed to extinction, so (t)=0, and t*=40s. The crystal melting data were fit in their entirety using the self-consistent Stefan number, which corresponds to the melt being superheated 0.63K above its equilibrium melting point, Tm=35.97K. The melting kinetics predicted over the entire the lifetime of this dendrite fragment using potential theory approach is in good agreement with experiment. The IDGE video data show only small disparities from the theoretical predictions. The second crystal analyzed, initially formed at a supercooling of 0.421K, did not melt with a constant C/A ratio. These melting data were “sectorized” into 5 sequential melting periods of 10 seconds each, except for the last sector, which was 4 seconds long. Sectorization allowed calculation of the C/A ratio, which was changing in this case. The same process of selecting a Stefan number was used, except each sector of melting was independently calculated using the initial and final lengths for that sector. Tip–shape analysis for PVA The analyses of USMP-4 data conducted to date indicate that the regression techniques, already used successfully to extract radius of curvature and shape of the tip of SCN dendrites, fail for pivalic acid dendrite tips recorded on USMP-4. In short, it has been found that 4th-order polynomials do not properly describe PVA tip shapes, and cannot provide consistent and reliable radii of curvature at the tip. The robustness of such methods is then judged by the invariance achieved in the radii values computed, versus the size of the interfacial sampling region in the measurement. Current efforts to obtain radii data to characterize a dendrite tip now use an older, one-parameter method of fitting the dendritic profile over various interface ranges to a perfect parabola. The canonical value for R is found by extrapolating the derived shape information back to the tip itself. Although all dendrites share strong similarities, and possess tips that appear to be parabolic—at least to first order—there nevertheless seems to be numerous ways to characterize them. At present, it is certainly far from clear as to how many parameters are required to describe the tip shape of PVA dendrites. This shortcoming remains where we desire to characterize a dendrite over its entire smooth, branchless region, rather than at the exact tip itself. It is clear that robust methods to extract crucial tip–radii values and tip–shape characteristics are both much needed yet lacking for anisotropic materials like pivalic acid. PVA continues to be one of the most experimentally well studied dendrite–forming systems, and one of only two systems where pure diffusion data is available from microgravity. Thus, it seems important to explore this issue more fully and characterize properly the interfacial shape of PVA dendrites grown under diffusion control. IDGE video data Perhaps the most exciting hardware modification to the IDGE was the addition of video storage for USMP-4, capable of on–board recording dendritic growth as 256–level grayscale video, 640x480 pixels, at 30 electronic frames per second. This hardware modification was planned primarily for demonstration purposes and technology advancement. None of the so–called “primary IDGE science” involved the acquisition of video data, although much was learned, particularly about the dynamics of dendritic growth and the kinetics of conduction-limited melting of mushy zones. RIDGE scientists have examined PVA video data and searched for subtle dynamic features such as the presence of dominant eigenfrequencies appearing in the dendrite growth velocity—a phenomenon never observed in terrestrial dendritic data. Similar measurements would entail searching for perturbation frequencies at fixed distances from the tip (as first observed by Dougherty and Gollub in terrestrial solution growth of ammonium bromide dendrites). Discussions held this year with scientists at ETH, Zürich, Switzerland, who study noble gas dendrites (xenon, krypton, etc.), proved to them using RIDGE data that noble gas dendrites are much more anisotropic than though previously. Also, recent estimates of surface tension anisotropy, computed by ab initio methods at Sandia-Livermore National Laboratory (J. Hoyt, et al.) show convincingly that hard-sphere fluids (such as the noble gases) have large ca. 3% anisotropies, precisely as verified for PVA dendrites in the IDGE/RIDGE program. Thus the scientific impact of the research conducted under RIDGE continues to assist others in the technical community.It is the purpose of RIDGE to explore topics beyond those considered as the primary science of the IDGE series. Specifically, we have 1) Developed new analysis tools for data extraction from the large number of available USMP-4 video tapes, focusing on transient dendritic growth behavior. 2) Converted selected video sequences from these studies to digital images on CD ROMS for public distribution and use. 3) Continued numerical studies based on the Green’s function method to assess the influence of the side–branch region on the steady–state features. 4) Determined in greater detail the influence of neighboring dendrites through thermal boundary layer interactions. 5) Analyzed IDGE data to determine the behavior of dendrites, including the average side–branch envelope. 6) Developed methods to observe tip dynamics using video methods, especially concerning the possible presence of eigenfrequencies. 7) Established the best procedures for analyzing the shape of PVA dendrites, the profiles for which do not conform to parabolas. 8) Continued the collaborative activities with other groups pursuing modeling efforts associated with dendritic solidification, and assisted by access to IDGE data. 9) Analyzed melting sequences from USMP-4 to establish kinetic laws for the melting of prolate spheroids.After completing three scheduled microgravity missions, the IDGE made significant contributions to our understanding of dendritic growth. In the time remaining prior to the termination of the IDGE, we expected to publish several new results that will be of interest to the scientific community that deals with dendritic growth and solidification issues. However, at its scheduled termination date August 31, 1999, we anticipated that a very large backlog of data analysis and reporting would remain uncompleted. These were issues not anticipated a decade earlier in the original IDGE science proposal. Although the IDGE project team accomplished more than was originally expected, or required, a great deal more still remains to be done. The significance of this project is to provide a follow–on to an ongoing MRD flight program, to frame the case that continuing ground–based data reduction and analysis will greatly enhance the understanding of existing or potential flight experiments in material science. During the second year of RIDGE, the major area within the IDGE database given major attention: 1) Tip radii and tip speed data were extracted in steady-state PVA dendrites; 2) Side branch spacings in PVA have also been measured from USMP-4 films; 3) Down-linked video data were partially analyzed as displacement-time plots to extract the power spectrum of the moving interface using Lomb periodigrams. RIDGE-supported scientists have shown the presence of dominant eigenfrequencies along the solid-liquid interface near the dendrite tip. These data, augmented by measurements of side-branch coherency, provide support for the trapped-wave hypothesis suggested by J.J. Xu. This is a novel description of the dendritic growth mechanism, which was not supported by experiment until the RIDGE analysis. Sidebranch Envelope To characterize the shape of the sidebranch envelope, the position of the sidebranch tips from the dendrite tip (x coordinate) were linearly regressed in the power law form shown in Equation 1, where the y coordinate is the coordinate normal to the growth axis, or the amplitude of the branches. alpha is the pre-exponential term, and beta is the exponential term. (SEE The annual/final report in .pdf format to view these formula. Added by editor.) . (1) The values of alpha and beta were averaged for each growth and plotted versus supercooling as shown in Figures 3 and 4. It appears that these values are independent of supercooling. Writing these values in the form of Equations 2 and 3: , (2) and . (3) The t-test indicated the convection-free and diffuso-convective environments produced significantly different alpha and beta values (probability of 0.0036 for alpha and 0.00068 for beta). These differences are clear based on the uncertainty measurements alone with out reference to the student t-test. Fig. 3 Pre-exponential term (alpha) for the sidebranch envelope as a function of supercooling for convection-free and diffuso-convective data. alpha appears relatively constant over this range of supercoolings and there is significant statistical difference between the convection and convection-free averages. Fig.4 . Exponential term (beta) for the sidebranch envelope as a function of supercooling for convection-free and diffuso-convective data. beta appears to be relatively constant over this range of supercoolings and there is significant statistical difference between the convection and convection-free averages. The sidebranch envelope could be fitted to a power law equation, where the pre-exponential and exponential terms calculated were found to be significantly different for the convection-free and diffuso-convective results. Convection also appeared to affect the sidebranch envelope in SCN dendrites. These results seem to indicate convection affects the thermal conditions near the solid-liquid interface, which alters the amplitude rather than the spacing of the sidebranches. Task Termination RIDGE was scheduled to end November, 30th, 2003 and it was extended until May 30th, 2004. Both IDGE and RIDGE contributed essentially to the understanding of dendritic solidification with direct implication for castings and ingots. We now have some knowledge of the evolution of the mushy zones, and we would like to explore more on future microgravity experiments to be performed on ISS. More... »

URL

https://taskbook.nasaprs.com/Publication/index.cfm?action=public_query_taskbook_content&TASKID=5211

Related SciGraph Publications

JSON-LD is the canonical representation for SciGraph data.

TIP: You can open this SciGraph record using an external JSON-LD service: JSON-LD Playground Google SDTT

[
  {
    "@context": "https://springernature.github.io/scigraph/jsonld/sgcontext.json", 
    "about": [
      {
        "id": "http://purl.org/au-research/vocabulary/anzsrc-for/2008/08", 
        "inDefinedTermSet": "http://purl.org/au-research/vocabulary/anzsrc-for/2008/", 
        "type": "DefinedTerm"
      }
    ], 
    "description": "Kinetics of Melting in Microgravity  The  kinetics of melting pivalic acid (PVA) dendrites was observed under convection-free conditions on STS-87 as part of the United States Microgravity Payload Mission (USMP-4) flown on Columbia in 1997. Analysis of video data show that PVA dendrites melt without relative motion with respect to the quiescent melt phase. Dendritic fragments display shrinking to extinction, with fragmentation occurring at higher initial supercoolings. The microgravity melting kinetics against which the experimental observations are compared is based on conduction-limited quasi-static melting under shape-preserving conditions. Agreement between analytic theory and our experiments is found when the melting process occurs under shape-preserving conditions as measured using the C/A ratio of individual needle-like crystal fragments.   Video data from USMP-4 have been analyzed to establish the rate of melting of individual crystallites in the dendritic mushy zone. The analysis uses potential theoretic methods to calculate analytic descriptions of the thermal field surrounding a prolate spheroidal crystal of PVA subject to melting. The new analysis (Glicksman et al., 2003) is the first that describes quasi-static melting under convection-free conditions. Direct comparison between the video data and the analytical predictions shows excellent correspondence. The IDGE data provided a unique opportunity to observe melting of dendrites without the complications of sedimentation or buoyancy-induced convection.   Mushy Zones Evolution  We analyzed two PVA crystals melting in microgravity, each formed originally as dendrite created in separate IDGE growth cycles. These dendrites grew from pure molten pivalic acid that was supercooled. The mushy zones consisted of approximately 4\\% solid when melting was initiated. The time needed to melt this mushy zone completely was approximately 12 minutes. The last large fragments to melt were selected for quantitative analysis. These fragments had initial lengths of C0=0.760cm and 0.695cm, respectively.   To calculate the melting kinetics of these fragments one requires the C/A ratio, the thermal diffusivity of the melt, and the Stefan number imposed by the melting cycle. The thermistors arranged within the IDGE thermostat were optimized for measuring the supercooling prior to dendritic growth quite precisely (\u00b10.002K). The subsequent temperature history within the growth chamber, especially during the melting portion of an experimental growth cycle, is, unfortunately, less certain, because temperature uncertainties arose from the lack of synchronization between the video clock and the mission clock. In view of this situation, one may instead adopt a self-consistent method of estimating the Stefan number in the melt during each melting sequence. The basis of the value of the self-consistent Stefan number is found from the C/A ratio (which equaled 12 for the entire melt cycle), the inital length, C0=0.760, and the length C(t) at a later time t where the fragment has decreased due to melting. In this instance the process of melting was followed to extinction, so (t)=0, and t*=40s.  The crystal melting data were fit in their entirety using the self-consistent Stefan number, which corresponds to the melt being superheated 0.63K above its equilibrium melting point, Tm=35.97K. The melting kinetics predicted over the entire the lifetime of this dendrite fragment using potential theory approach is in good agreement with experiment. The IDGE video data show only small disparities from the theoretical predictions. The second crystal analyzed, initially formed at a supercooling of 0.421K, did not melt with a constant C/A ratio. These melting data were \u201csectorized\u201d into 5 sequential melting periods of 10 seconds each, except for the last sector, which was 4 seconds long. Sectorization allowed calculation of the C/A ratio, which was changing in this case. The same process of selecting a Stefan number was used, except each sector of melting was independently calculated using the initial and final lengths for that sector.   Tip\u2013shape analysis for PVA  The analyses of USMP-4 data conducted to date indicate that the regression techniques, already used successfully to extract radius of curvature and shape of the tip of SCN dendrites, fail for pivalic acid dendrite tips recorded on USMP-4. In short, it has been found that 4th-order polynomials do not properly describe PVA tip shapes, and cannot provide consistent and reliable radii of curvature at the tip. The robustness of such methods is then judged by the invariance achieved in the radii values computed, versus the size of the interfacial sampling region in the measurement. Current efforts to obtain radii data to characterize a dendrite tip now use an older, one-parameter method of fitting the dendritic profile over various interface ranges to a perfect parabola. The canonical value for R is found by extrapolating the derived shape information back to the tip itself.   Although all dendrites share strong similarities, and possess tips that appear to be parabolic\u2014at least to first order\u2014there nevertheless seems to be numerous ways to characterize them. At present, it is certainly far from clear as to how many parameters are required to describe the tip shape of PVA dendrites. This shortcoming remains where we desire to characterize a dendrite over its entire smooth, branchless region, rather than at the exact tip itself. It is clear that robust methods to extract crucial tip\u2013radii values and tip\u2013shape characteristics are both much needed yet lacking for anisotropic materials like pivalic acid. PVA continues to be one of the most experimentally well studied dendrite\u2013forming systems, and one of only two systems where pure diffusion data is available from microgravity. Thus, it seems important to explore this issue more fully and characterize properly the interfacial shape of PVA dendrites grown under diffusion control.   IDGE video data  Perhaps the most exciting hardware modification to the IDGE was the addition of video storage for USMP-4, capable of on\u2013board recording dendritic growth as 256\u2013level grayscale video, 640x480 pixels, at 30 electronic frames per second. This hardware modification was planned primarily for demonstration purposes and technology advancement. None of the so\u2013called \u201cprimary IDGE science\u201d involved the acquisition of video data, although much was learned, particularly about the dynamics of dendritic growth and the kinetics of conduction-limited melting of mushy zones.   RIDGE scientists have examined PVA video data and searched for subtle dynamic features such as the presence of dominant eigenfrequencies appearing in the dendrite growth velocity\u2014a phenomenon never observed in terrestrial dendritic data. Similar measurements would entail searching for perturbation frequencies at fixed distances from the tip (as first observed by Dougherty and Gollub in terrestrial solution growth of ammonium bromide dendrites). Discussions held this year with scientists at ETH, Z\u00fcrich, Switzerland, who study noble gas dendrites (xenon, krypton, etc.), proved to them using RIDGE data that noble gas dendrites are much more anisotropic than though previously. Also, recent estimates of surface tension anisotropy, computed by ab initio methods at Sandia-Livermore National Laboratory (J. Hoyt, et al.) show convincingly that hard-sphere fluids (such as the noble gases) have large ca. 3% anisotropies, precisely as verified for PVA dendrites in the IDGE/RIDGE program. Thus the scientific impact of the research conducted under RIDGE continues to assist others in the technical community.It is the purpose of RIDGE to explore topics beyond those considered as the primary science of the IDGE series. Specifically, we have 1) Developed new analysis tools for data extraction from the large number of available USMP-4 video tapes, focusing on transient dendritic growth behavior. 2) Converted selected video sequences from these studies to digital images on CD ROMS for public distribution and use. 3) Continued numerical studies based on the Green\u2019s function method to assess the influence of the side\u2013branch region on the steady\u2013state features. 4) Determined in greater detail the influence of neighboring dendrites through thermal boundary layer interactions. 5) Analyzed IDGE data to determine the behavior of dendrites, including the average side\u2013branch envelope. 6) Developed methods to observe tip dynamics using video methods, especially concerning the possible presence of eigenfrequencies. 7) Established the best procedures for analyzing the shape of PVA dendrites, the profiles for which do not conform to parabolas. 8) Continued the collaborative activities with other groups pursuing modeling efforts associated with dendritic solidification, and assisted by access to IDGE data. 9) Analyzed melting sequences from USMP-4 to establish kinetic laws for the melting of prolate spheroids.After completing three scheduled microgravity missions, the IDGE made significant contributions to our understanding of dendritic growth. In the time remaining prior to the termination of the IDGE, we expected to publish several new results that will be of interest to the scientific community that deals with dendritic growth and solidification issues. However, at its scheduled termination date August 31, 1999, we anticipated that a very large backlog of data analysis and reporting would remain uncompleted. These were issues not anticipated a decade earlier in the original IDGE science proposal. Although the IDGE project team accomplished more than was originally expected, or required, a great deal more still remains to be done. The significance of this project is to provide a follow\u2013on to an ongoing MRD flight program, to frame the case that continuing ground\u2013based data reduction and analysis will greatly enhance the understanding of existing or potential flight experiments in material science.\n\nDuring the second year of RIDGE, the major area within the IDGE database given major attention: 1) Tip radii and tip speed data were extracted in steady-state PVA dendrites; 2) Side branch spacings in PVA have also been measured from USMP-4 films; 3) Down-linked video data were partially analyzed as displacement-time plots to extract the power spectrum of the moving interface using Lomb periodigrams. RIDGE-supported scientists have shown the presence of dominant eigenfrequencies along the solid-liquid interface near the dendrite tip. These data, augmented by measurements of side-branch coherency, provide support for the trapped-wave hypothesis suggested by J.J. Xu. This is a novel description of the dendritic growth mechanism, which was not supported by experiment until the RIDGE analysis.    Sidebranch Envelope  To characterize the shape of the sidebranch envelope, the position of the sidebranch tips from the dendrite tip (x coordinate) were linearly regressed in the power law form shown in Equation 1, where the y coordinate is the coordinate normal to the growth axis, or the amplitude of the branches.  alpha is the pre-exponential term, and beta is the exponential term.  (SEE The annual/final report in .pdf format to view these formula. Added by editor.)     .   (1)  The values of alpha and beta were averaged for each growth and plotted versus supercooling as shown in Figures 3 and 4.  It appears that these values are independent of supercooling.  Writing these values in the form of Equations 2 and 3:       ,  (2) and      .  (3)  The t-test indicated the convection-free and diffuso-convective environments produced significantly different alpha and beta values (probability of 0.0036 for alpha and 0.00068 for beta).  These differences are clear based on the uncertainty measurements alone with out reference to the student t-test.    Fig. 3 Pre-exponential term (alpha) for the sidebranch envelope as a function of supercooling for convection-free and diffuso-convective data.  alpha appears relatively constant over this range of supercoolings and there is significant statistical difference between the convection and convection-free averages.      Fig.4 . Exponential term (beta) for the sidebranch envelope as a function of supercooling for convection-free and diffuso-convective data.  beta appears to be relatively constant over this range of supercoolings and there is significant statistical difference between the convection and convection-free averages.   The sidebranch envelope could be fitted to a power law equation, where the pre-exponential and exponential terms calculated were found to be significantly different for the convection-free and diffuso-convective results.  Convection also appeared to affect the sidebranch envelope in SCN dendrites. These results seem to indicate convection affects the thermal conditions near the solid-liquid interface, which alters the amplitude rather than the spacing of the sidebranches.   Task Termination  RIDGE was scheduled to end November, 30th, 2003 and it was extended until May 30th, 2004. Both IDGE and RIDGE contributed essentially to the understanding of dendritic solidification with direct implication for castings and ingots. We now have some knowledge of the evolution of the mushy zones, and we would like to explore more on future microgravity experiments to be performed on ISS.", 
    "endDate": "2004-05-30", 
    "funder": {
      "id": "http://www.grid.ac/institutes/grid.238252.c", 
      "type": "Organization"
    }, 
    "id": "sg:grant.8747082", 
    "identifier": [
      {
        "name": "dimensions_id", 
        "type": "PropertyValue", 
        "value": [
          "grant.8747082"
        ]
      }, 
      {
        "name": "nasa_id", 
        "type": "PropertyValue", 
        "value": [
          "NAG8-1696"
        ]
      }
    ], 
    "keywords": [
      "Stefan number", 
      "mushy zone", 
      "solid-liquid interface", 
      "range of supercooling", 
      "dendritic solidification", 
      "dominant eigenfrequencies", 
      "mushy zone evolution", 
      "displacement\u2013time plots", 
      "dendrite tip", 
      "buoyancy-induced convection", 
      "boundary layer interaction", 
      "behavior of dendrites", 
      "tip shape", 
      "future microgravity experiments", 
      "dendritic growth behavior", 
      "hardware modifications", 
      "convection-free conditions", 
      "dendritic growth", 
      "dendrite growth velocity", 
      "solidification issues", 
      "Isothermal Dendritic Growth Experiment", 
      "thermal diffusivity", 
      "thermal field", 
      "dendritic mushy zone", 
      "layer interaction", 
      "process of melting", 
      "United States Microgravity Payload Mission", 
      "rate of melting", 
      "power law equation", 
      "dendrite fragments", 
      "payload missions", 
      "microgravity experiments", 
      "interfacial shape", 
      "anisotropic materials", 
      "kinetics of melting", 
      "surface tension anisotropy", 
      "numerical study", 
      "temperature history", 
      "radius of curvature", 
      "tip radius", 
      "flight experiments", 
      "melting cycles", 
      "melting process", 
      "growth behavior", 
      "analytical predictions", 
      "convection", 
      "function method", 
      "temperature uncertainty", 
      "speed data", 
      "pre-exponential term", 
      "diffusion control", 
      "self-consistent method", 
      "perturbation frequency", 
      "one-parameter method", 
      "melting sequence", 
      "growth mechanism", 
      "thermal conditions", 
      "potential theory approach", 
      "relative motion", 
      "law equation", 
      "materials science", 
      "steady-state features", 
      "demonstration purposes", 
      "solidification", 
      "tip dynamics", 
      "perfect parabola", 
      "kinetic law", 
      "melting point", 
      "flight program", 
      "tension anisotropy", 
      "National Laboratory", 
      "melting period", 
      "interface", 
      "eigenfrequencies", 
      "experimental observations", 
      "good agreement", 
      "spheroidal crystals", 
      "zone evolution", 
      "ridge analysis", 
      "dendritic growth mechanism", 
      "supercooling", 
      "Green's function method", 
      "power-law form", 
      "modeling efforts", 
      "PVA crystals", 
      "melting", 
      "individual crystallites", 
      "technology advancement", 
      "prolate spheroid", 
      "melt", 
      "initial supercooling", 
      "order polynomial", 
      "excellent correspondence", 
      "melt phase", 
      "theoretical predictions", 
      "initial length", 
      "tip", 
      "microgravity", 
      "law form", 
      "technical community", 
      "spacing", 
      "new analysis tools", 
      "diffusion data", 
      "shape", 
      "power spectrum", 
      "exponential terms", 
      "ingots", 
      "casting", 
      "measurements", 
      "branch spacing", 
      "kinetics", 
      "STS-87", 
      "zone", 
      "radius values", 
      "radius", 
      "dynamic features", 
      "films", 
      "anisotropy", 
      "thermistors", 
      "robust method", 
      "ratio", 
      "similar measurements", 
      "diffusivity", 
      "conditions", 
      "envelope", 
      "uncertainty measurement", 
      "experiments", 
      "method", 
      "amplitude", 
      "same process", 
      "process", 
      "analysis tools", 
      "velocity", 
      "crystals", 
      "lack of synchronization", 
      "analytic theory", 
      "curvature", 
      "cycle", 
      "prediction", 
      "mission", 
      "behavior", 
      "major attention", 
      "growth experiments", 
      "first order", 
      "crystallites", 
      "research activities", 
      "growth axis", 
      "Equation 2", 
      "grayscale video", 
      "agreement", 
      "range", 
      "digital images", 
      "materials", 
      "ROMS", 
      "influence", 
      "tape", 
      "hard-sphere fluid", 
      "growth velocity", 
      "analytic description", 
      "equation 1", 
      "y coordinates", 
      "system", 
      "parabola", 
      "motion", 
      "robustness", 
      "thermostat", 
      "large Ca", 
      "seconds", 
      "such methods", 
      "Figure 3", 
      "length", 
      "time t", 
      "equilibrium melting point", 
      "storage", 
      "results", 
      "coherency", 
      "parabolic", 
      "values", 
      "later time t", 
      "reliable radii", 
      "fluid", 
      "chamber", 
      "dynamics", 
      "equations", 
      "direct comparison", 
      "parameters", 
      "terms", 
      "dendritic fragments", 
      "dendrites", 
      "radius data", 
      "lifetime", 
      "phase", 
      "extraction", 
      "modification", 
      "potential theoretic methods", 
      "data reduction", 
      "pixels", 
      "uncertainty", 
      "ridge", 
      "coordinates", 
      "significant contribution", 
      "field", 
      "analysis", 
      "characteristics", 
      "profile", 
      "calculations", 
      "technique", 
      "time", 
      "shape information", 
      "last sector", 
      "board", 
      "evolution", 
      "clock", 
      "frequency", 
      "canonical value", 
      "new results", 
      "phenomenon", 
      "video data", 
      "size", 
      "large number", 
      "great deal", 
      "greater detail", 
      "final length", 
      "order", 
      "region", 
      "detail", 
      "sedimentation", 
      "sectorization", 
      "distribution", 
      "frame", 
      "growth", 
      "issues", 
      "regression techniques", 
      "synchronization", 
      "reduction", 
      "novel description", 
      "quantitative analysis", 
      "features", 
      "ridge data", 
      "description", 
      "current efforts", 
      "law", 
      "advancement", 
      "pivalic acid", 
      "images", 
      "number", 
      "sidebranches", 
      "video tape", 
      "shortcomings", 
      "comparison", 
      "video sequences", 
      "distance", 
      "data", 
      "sector", 
      "environment", 
      "beta values", 
      "presence", 
      "scientific community", 
      "point", 
      "reference", 
      "purpose", 
      "respect", 
      "control", 
      "laboratory", 
      "new analysis", 
      "addition", 
      "approach", 
      "ISS", 
      "project team", 
      "neighboring dendrites", 
      "spectra", 
      "area", 
      "rate", 
      "sampling regions", 
      "deal", 
      "major areas", 
      "function", 
      "position", 
      "axis", 
      "possible presence", 
      "video method", 
      "procedure", 
      "spheroids", 
      "tool", 
      "use", 
      "project", 
      "best procedure", 
      "cases", 
      "observations", 
      "mechanism", 
      "form", 
      "study", 
      "efforts", 
      "plots", 
      "series", 
      "part", 
      "theory", 
      "ETH", 
      "theoretic methods", 
      "growth cycle", 
      "impact", 
      "estimates", 
      "unique opportunity", 
      "crystal fragments", 
      "portion", 
      "direct implications", 
      "Ca", 
      "interest", 
      "contribution", 
      "video storage", 
      "interaction", 
      "strong similarities", 
      "way", 
      "numerous ways", 
      "acid", 
      "understanding", 
      "attention", 
      "large backlog", 
      "average", 
      "basis", 
      "present", 
      "Z\u00fcrich", 
      "polynomials", 
      "second crystal", 
      "situation", 
      "research", 
      "acquisition", 
      "data analysis", 
      "proposal", 
      "ab initio methods", 
      "values of alpha", 
      "differences", 
      "public distribution", 
      "recent estimates", 
      "branches", 
      "theory approach", 
      "information", 
      "correspondence", 
      "science", 
      "scientists", 
      "termination", 
      "minutes", 
      "decades", 
      "view", 
      "growth chamber", 
      "Xu", 
      "instances", 
      "backlog", 
      "program", 
      "large fragments", 
      "opportunities", 
      "initio methods", 
      "support", 
      "SCN", 
      "topic", 
      "extinction", 
      "sequence", 
      "video", 
      "invariance", 
      "discussion", 
      "entirety", 
      "period", 
      "fragmentation", 
      "Switzerland", 
      "significance", 
      "knowledge", 
      "lack", 
      "small disparities", 
      "activity", 
      "science proposals", 
      "years", 
      "Columbia", 
      "date", 
      "access", 
      "team", 
      "CD-ROMS", 
      "fragments", 
      "scientific impact", 
      "similarity", 
      "statistical difference", 
      "significant statistical difference", 
      "database", 
      "task termination", 
      "history", 
      "community", 
      "implications", 
      "Student's t-test", 
      "data extraction", 
      "t-test", 
      "hypothesis", 
      "second year", 
      "group", 
      "subjects", 
      "disparities", 
      "primary science", 
      "beta", 
      "collaborative activities", 
      "reporting", 
      "complications", 
      "alpha", 
      "different alpha", 
      "dendritic profiles", 
      "shape-preserving conditions"
    ], 
    "name": "Follow-on Research Activities for the Rensselaer Isothermal Dendritic Growth Experiment", 
    "recipient": [
      {
        "id": "http://www.grid.ac/institutes/grid.33647.35", 
        "type": "Organization"
      }, 
      {
        "id": "http://www.grid.ac/institutes/grid.254514.3", 
        "type": "Organization"
      }, 
      {
        "affiliation": {
          "id": "http://www.grid.ac/institutes/None", 
          "name": "Rensselaer Polytechnic Institute", 
          "type": "Organization"
        }, 
        "familyName": "Glicksman", 
        "givenName": "Martin", 
        "id": "sg:person.010720014261.43", 
        "type": "Person"
      }, 
      {
        "member": "sg:person.010720014261.43", 
        "roleName": "PI", 
        "type": "Role"
      }, 
      {
        "affiliation": {
          "id": "http://www.grid.ac/institutes/None", 
          "name": "College of the Holy Cross", 
          "type": "Organization"
        }, 
        "familyName": "Koss", 
        "givenName": "M.", 
        "id": "sg:person.013371002302.98", 
        "type": "Person"
      }, 
      {
        "member": "sg:person.013371002302.98", 
        "roleName": "Co-PI", 
        "type": "Role"
      }
    ], 
    "sameAs": [
      "https://app.dimensions.ai/details/grant/grant.8747082"
    ], 
    "sdDataset": "grants", 
    "sdDatePublished": "2022-08-04T17:24", 
    "sdLicense": "https://scigraph.springernature.com/explorer/license/", 
    "sdPublisher": {
      "name": "Springer Nature - SN SciGraph project", 
      "type": "Organization"
    }, 
    "sdSource": "s3://com-springernature-scigraph/baseset/20220804/entities/gbq_results/grant/grant_63.jsonl", 
    "startDate": "2000-05-01", 
    "type": "MonetaryGrant", 
    "url": "https://taskbook.nasaprs.com/Publication/index.cfm?action=public_query_taskbook_content&TASKID=5211"
  }
]
 

Download the RDF metadata as:  json-ld nt turtle xml License info

HOW TO GET THIS DATA PROGRAMMATICALLY:

JSON-LD is a popular format for linked data which is fully compatible with JSON.

curl -H 'Accept: application/ld+json' 'https://scigraph.springernature.com/grant.8747082'

N-Triples is a line-based linked data format ideal for batch operations.

curl -H 'Accept: application/n-triples' 'https://scigraph.springernature.com/grant.8747082'

Turtle is a human-readable linked data format.

curl -H 'Accept: text/turtle' 'https://scigraph.springernature.com/grant.8747082'

RDF/XML is a standard XML format for linked data.

curl -H 'Accept: application/rdf+xml' 'https://scigraph.springernature.com/grant.8747082'


 

This table displays all metadata directly associated to this object as RDF triples.

455 TRIPLES      17 PREDICATES      426 URIs      416 LITERALS      5 BLANK NODES

Subject Predicate Object
1 sg:grant.8747082 schema:about anzsrc-for:08
2 schema:description Kinetics of Melting in Microgravity The kinetics of melting pivalic acid (PVA) dendrites was observed under convection-free conditions on STS-87 as part of the United States Microgravity Payload Mission (USMP-4) flown on Columbia in 1997. Analysis of video data show that PVA dendrites melt without relative motion with respect to the quiescent melt phase. Dendritic fragments display shrinking to extinction, with fragmentation occurring at higher initial supercoolings. The microgravity melting kinetics against which the experimental observations are compared is based on conduction-limited quasi-static melting under shape-preserving conditions. Agreement between analytic theory and our experiments is found when the melting process occurs under shape-preserving conditions as measured using the C/A ratio of individual needle-like crystal fragments. Video data from USMP-4 have been analyzed to establish the rate of melting of individual crystallites in the dendritic mushy zone. The analysis uses potential theoretic methods to calculate analytic descriptions of the thermal field surrounding a prolate spheroidal crystal of PVA subject to melting. The new analysis (Glicksman et al., 2003) is the first that describes quasi-static melting under convection-free conditions. Direct comparison between the video data and the analytical predictions shows excellent correspondence. The IDGE data provided a unique opportunity to observe melting of dendrites without the complications of sedimentation or buoyancy-induced convection. Mushy Zones Evolution We analyzed two PVA crystals melting in microgravity, each formed originally as dendrite created in separate IDGE growth cycles. These dendrites grew from pure molten pivalic acid that was supercooled. The mushy zones consisted of approximately 4\% solid when melting was initiated. The time needed to melt this mushy zone completely was approximately 12 minutes. The last large fragments to melt were selected for quantitative analysis. These fragments had initial lengths of C0=0.760cm and 0.695cm, respectively. To calculate the melting kinetics of these fragments one requires the C/A ratio, the thermal diffusivity of the melt, and the Stefan number imposed by the melting cycle. The thermistors arranged within the IDGE thermostat were optimized for measuring the supercooling prior to dendritic growth quite precisely (±0.002K). The subsequent temperature history within the growth chamber, especially during the melting portion of an experimental growth cycle, is, unfortunately, less certain, because temperature uncertainties arose from the lack of synchronization between the video clock and the mission clock. In view of this situation, one may instead adopt a self-consistent method of estimating the Stefan number in the melt during each melting sequence. The basis of the value of the self-consistent Stefan number is found from the C/A ratio (which equaled 12 for the entire melt cycle), the inital length, C0=0.760, and the length C(t) at a later time t where the fragment has decreased due to melting. In this instance the process of melting was followed to extinction, so (t)=0, and t*=40s. The crystal melting data were fit in their entirety using the self-consistent Stefan number, which corresponds to the melt being superheated 0.63K above its equilibrium melting point, Tm=35.97K. The melting kinetics predicted over the entire the lifetime of this dendrite fragment using potential theory approach is in good agreement with experiment. The IDGE video data show only small disparities from the theoretical predictions. The second crystal analyzed, initially formed at a supercooling of 0.421K, did not melt with a constant C/A ratio. These melting data were “sectorized” into 5 sequential melting periods of 10 seconds each, except for the last sector, which was 4 seconds long. Sectorization allowed calculation of the C/A ratio, which was changing in this case. The same process of selecting a Stefan number was used, except each sector of melting was independently calculated using the initial and final lengths for that sector. Tip–shape analysis for PVA The analyses of USMP-4 data conducted to date indicate that the regression techniques, already used successfully to extract radius of curvature and shape of the tip of SCN dendrites, fail for pivalic acid dendrite tips recorded on USMP-4. In short, it has been found that 4th-order polynomials do not properly describe PVA tip shapes, and cannot provide consistent and reliable radii of curvature at the tip. The robustness of such methods is then judged by the invariance achieved in the radii values computed, versus the size of the interfacial sampling region in the measurement. Current efforts to obtain radii data to characterize a dendrite tip now use an older, one-parameter method of fitting the dendritic profile over various interface ranges to a perfect parabola. The canonical value for R is found by extrapolating the derived shape information back to the tip itself. Although all dendrites share strong similarities, and possess tips that appear to be parabolic—at least to first order—there nevertheless seems to be numerous ways to characterize them. At present, it is certainly far from clear as to how many parameters are required to describe the tip shape of PVA dendrites. This shortcoming remains where we desire to characterize a dendrite over its entire smooth, branchless region, rather than at the exact tip itself. It is clear that robust methods to extract crucial tip–radii values and tip–shape characteristics are both much needed yet lacking for anisotropic materials like pivalic acid. PVA continues to be one of the most experimentally well studied dendrite–forming systems, and one of only two systems where pure diffusion data is available from microgravity. Thus, it seems important to explore this issue more fully and characterize properly the interfacial shape of PVA dendrites grown under diffusion control. IDGE video data Perhaps the most exciting hardware modification to the IDGE was the addition of video storage for USMP-4, capable of on–board recording dendritic growth as 256–level grayscale video, 640x480 pixels, at 30 electronic frames per second. This hardware modification was planned primarily for demonstration purposes and technology advancement. None of the so–called “primary IDGE science” involved the acquisition of video data, although much was learned, particularly about the dynamics of dendritic growth and the kinetics of conduction-limited melting of mushy zones. RIDGE scientists have examined PVA video data and searched for subtle dynamic features such as the presence of dominant eigenfrequencies appearing in the dendrite growth velocity—a phenomenon never observed in terrestrial dendritic data. Similar measurements would entail searching for perturbation frequencies at fixed distances from the tip (as first observed by Dougherty and Gollub in terrestrial solution growth of ammonium bromide dendrites). Discussions held this year with scientists at ETH, Zürich, Switzerland, who study noble gas dendrites (xenon, krypton, etc.), proved to them using RIDGE data that noble gas dendrites are much more anisotropic than though previously. Also, recent estimates of surface tension anisotropy, computed by ab initio methods at Sandia-Livermore National Laboratory (J. Hoyt, et al.) show convincingly that hard-sphere fluids (such as the noble gases) have large ca. 3% anisotropies, precisely as verified for PVA dendrites in the IDGE/RIDGE program. Thus the scientific impact of the research conducted under RIDGE continues to assist others in the technical community.It is the purpose of RIDGE to explore topics beyond those considered as the primary science of the IDGE series. Specifically, we have 1) Developed new analysis tools for data extraction from the large number of available USMP-4 video tapes, focusing on transient dendritic growth behavior. 2) Converted selected video sequences from these studies to digital images on CD ROMS for public distribution and use. 3) Continued numerical studies based on the Green’s function method to assess the influence of the side–branch region on the steady–state features. 4) Determined in greater detail the influence of neighboring dendrites through thermal boundary layer interactions. 5) Analyzed IDGE data to determine the behavior of dendrites, including the average side–branch envelope. 6) Developed methods to observe tip dynamics using video methods, especially concerning the possible presence of eigenfrequencies. 7) Established the best procedures for analyzing the shape of PVA dendrites, the profiles for which do not conform to parabolas. 8) Continued the collaborative activities with other groups pursuing modeling efforts associated with dendritic solidification, and assisted by access to IDGE data. 9) Analyzed melting sequences from USMP-4 to establish kinetic laws for the melting of prolate spheroids.After completing three scheduled microgravity missions, the IDGE made significant contributions to our understanding of dendritic growth. In the time remaining prior to the termination of the IDGE, we expected to publish several new results that will be of interest to the scientific community that deals with dendritic growth and solidification issues. However, at its scheduled termination date August 31, 1999, we anticipated that a very large backlog of data analysis and reporting would remain uncompleted. These were issues not anticipated a decade earlier in the original IDGE science proposal. Although the IDGE project team accomplished more than was originally expected, or required, a great deal more still remains to be done. The significance of this project is to provide a follow–on to an ongoing MRD flight program, to frame the case that continuing ground–based data reduction and analysis will greatly enhance the understanding of existing or potential flight experiments in material science. During the second year of RIDGE, the major area within the IDGE database given major attention: 1) Tip radii and tip speed data were extracted in steady-state PVA dendrites; 2) Side branch spacings in PVA have also been measured from USMP-4 films; 3) Down-linked video data were partially analyzed as displacement-time plots to extract the power spectrum of the moving interface using Lomb periodigrams. RIDGE-supported scientists have shown the presence of dominant eigenfrequencies along the solid-liquid interface near the dendrite tip. These data, augmented by measurements of side-branch coherency, provide support for the trapped-wave hypothesis suggested by J.J. Xu. This is a novel description of the dendritic growth mechanism, which was not supported by experiment until the RIDGE analysis. Sidebranch Envelope To characterize the shape of the sidebranch envelope, the position of the sidebranch tips from the dendrite tip (x coordinate) were linearly regressed in the power law form shown in Equation 1, where the y coordinate is the coordinate normal to the growth axis, or the amplitude of the branches. alpha is the pre-exponential term, and beta is the exponential term. (SEE The annual/final report in .pdf format to view these formula. Added by editor.) . (1) The values of alpha and beta were averaged for each growth and plotted versus supercooling as shown in Figures 3 and 4. It appears that these values are independent of supercooling. Writing these values in the form of Equations 2 and 3: , (2) and . (3) The t-test indicated the convection-free and diffuso-convective environments produced significantly different alpha and beta values (probability of 0.0036 for alpha and 0.00068 for beta). These differences are clear based on the uncertainty measurements alone with out reference to the student t-test. Fig. 3 Pre-exponential term (alpha) for the sidebranch envelope as a function of supercooling for convection-free and diffuso-convective data. alpha appears relatively constant over this range of supercoolings and there is significant statistical difference between the convection and convection-free averages. Fig.4 . Exponential term (beta) for the sidebranch envelope as a function of supercooling for convection-free and diffuso-convective data. beta appears to be relatively constant over this range of supercoolings and there is significant statistical difference between the convection and convection-free averages. The sidebranch envelope could be fitted to a power law equation, where the pre-exponential and exponential terms calculated were found to be significantly different for the convection-free and diffuso-convective results. Convection also appeared to affect the sidebranch envelope in SCN dendrites. These results seem to indicate convection affects the thermal conditions near the solid-liquid interface, which alters the amplitude rather than the spacing of the sidebranches. Task Termination RIDGE was scheduled to end November, 30th, 2003 and it was extended until May 30th, 2004. Both IDGE and RIDGE contributed essentially to the understanding of dendritic solidification with direct implication for castings and ingots. We now have some knowledge of the evolution of the mushy zones, and we would like to explore more on future microgravity experiments to be performed on ISS.
3 schema:endDate 2004-05-30
4 schema:funder grid-institutes:grid.238252.c
5 schema:identifier N50498cf675294571a896554a9a069ca5
6 N90270004f0d24c0cb4d51c72a41af97c
7 schema:keywords CD-ROMS
8 Ca
9 Columbia
10 ETH
11 Equation 2
12 Figure 3
13 Green's function method
14 ISS
15 Isothermal Dendritic Growth Experiment
16 National Laboratory
17 PVA crystals
18 ROMS
19 SCN
20 STS-87
21 Stefan number
22 Student's t-test
23 Switzerland
24 United States Microgravity Payload Mission
25 Xu
26 Zürich
27 ab initio methods
28 access
29 acid
30 acquisition
31 activity
32 addition
33 advancement
34 agreement
35 alpha
36 amplitude
37 analysis
38 analysis tools
39 analytic description
40 analytic theory
41 analytical predictions
42 anisotropic materials
43 anisotropy
44 approach
45 area
46 attention
47 average
48 axis
49 backlog
50 basis
51 behavior
52 behavior of dendrites
53 best procedure
54 beta
55 beta values
56 board
57 boundary layer interaction
58 branch spacing
59 branches
60 buoyancy-induced convection
61 calculations
62 canonical value
63 cases
64 casting
65 chamber
66 characteristics
67 clock
68 coherency
69 collaborative activities
70 community
71 comparison
72 complications
73 conditions
74 contribution
75 control
76 convection
77 convection-free conditions
78 coordinates
79 correspondence
80 crystal fragments
81 crystallites
82 crystals
83 current efforts
84 curvature
85 cycle
86 data
87 data analysis
88 data extraction
89 data reduction
90 database
91 date
92 deal
93 decades
94 demonstration purposes
95 dendrite fragments
96 dendrite growth velocity
97 dendrite tip
98 dendrites
99 dendritic fragments
100 dendritic growth
101 dendritic growth behavior
102 dendritic growth mechanism
103 dendritic mushy zone
104 dendritic profiles
105 dendritic solidification
106 description
107 detail
108 differences
109 different alpha
110 diffusion control
111 diffusion data
112 diffusivity
113 digital images
114 direct comparison
115 direct implications
116 discussion
117 disparities
118 displacement–time plots
119 distance
120 distribution
121 dominant eigenfrequencies
122 dynamic features
123 dynamics
124 efforts
125 eigenfrequencies
126 entirety
127 envelope
128 environment
129 equation 1
130 equations
131 equilibrium melting point
132 estimates
133 evolution
134 excellent correspondence
135 experimental observations
136 experiments
137 exponential terms
138 extinction
139 extraction
140 features
141 field
142 films
143 final length
144 first order
145 flight experiments
146 flight program
147 fluid
148 form
149 fragmentation
150 fragments
151 frame
152 frequency
153 function
154 function method
155 future microgravity experiments
156 good agreement
157 grayscale video
158 great deal
159 greater detail
160 group
161 growth
162 growth axis
163 growth behavior
164 growth chamber
165 growth cycle
166 growth experiments
167 growth mechanism
168 growth velocity
169 hard-sphere fluid
170 hardware modifications
171 history
172 hypothesis
173 images
174 impact
175 implications
176 individual crystallites
177 influence
178 information
179 ingots
180 initial length
181 initial supercooling
182 initio methods
183 instances
184 interaction
185 interest
186 interface
187 interfacial shape
188 invariance
189 issues
190 kinetic law
191 kinetics
192 kinetics of melting
193 knowledge
194 laboratory
195 lack
196 lack of synchronization
197 large Ca
198 large backlog
199 large fragments
200 large number
201 last sector
202 later time t
203 law
204 law equation
205 law form
206 layer interaction
207 length
208 lifetime
209 major areas
210 major attention
211 materials
212 materials science
213 measurements
214 mechanism
215 melt
216 melt phase
217 melting
218 melting cycles
219 melting period
220 melting point
221 melting process
222 melting sequence
223 method
224 microgravity
225 microgravity experiments
226 minutes
227 mission
228 modeling efforts
229 modification
230 motion
231 mushy zone
232 mushy zone evolution
233 neighboring dendrites
234 new analysis
235 new analysis tools
236 new results
237 novel description
238 number
239 numerical study
240 numerous ways
241 observations
242 one-parameter method
243 opportunities
244 order
245 order polynomial
246 parabola
247 parabolic
248 parameters
249 part
250 payload missions
251 perfect parabola
252 period
253 perturbation frequency
254 phase
255 phenomenon
256 pivalic acid
257 pixels
258 plots
259 point
260 polynomials
261 portion
262 position
263 possible presence
264 potential theoretic methods
265 potential theory approach
266 power law equation
267 power spectrum
268 power-law form
269 pre-exponential term
270 prediction
271 presence
272 present
273 primary science
274 procedure
275 process
276 process of melting
277 profile
278 program
279 project
280 project team
281 prolate spheroid
282 proposal
283 public distribution
284 purpose
285 quantitative analysis
286 radius
287 radius data
288 radius of curvature
289 radius values
290 range
291 range of supercooling
292 rate
293 rate of melting
294 ratio
295 recent estimates
296 reduction
297 reference
298 region
299 regression techniques
300 relative motion
301 reliable radii
302 reporting
303 research
304 research activities
305 respect
306 results
307 ridge
308 ridge analysis
309 ridge data
310 robust method
311 robustness
312 same process
313 sampling regions
314 science
315 science proposals
316 scientific community
317 scientific impact
318 scientists
319 second crystal
320 second year
321 seconds
322 sector
323 sectorization
324 sedimentation
325 self-consistent method
326 sequence
327 series
328 shape
329 shape information
330 shape-preserving conditions
331 shortcomings
332 sidebranches
333 significance
334 significant contribution
335 significant statistical difference
336 similar measurements
337 similarity
338 situation
339 size
340 small disparities
341 solid-liquid interface
342 solidification
343 solidification issues
344 spacing
345 spectra
346 speed data
347 spheroidal crystals
348 spheroids
349 statistical difference
350 steady-state features
351 storage
352 strong similarities
353 study
354 subjects
355 such methods
356 supercooling
357 support
358 surface tension anisotropy
359 synchronization
360 system
361 t-test
362 tape
363 task termination
364 team
365 technical community
366 technique
367 technology advancement
368 temperature history
369 temperature uncertainty
370 tension anisotropy
371 termination
372 terms
373 theoretic methods
374 theoretical predictions
375 theory
376 theory approach
377 thermal conditions
378 thermal diffusivity
379 thermal field
380 thermistors
381 thermostat
382 time
383 time t
384 tip
385 tip dynamics
386 tip radius
387 tip shape
388 tool
389 topic
390 uncertainty
391 uncertainty measurement
392 understanding
393 unique opportunity
394 use
395 values
396 values of alpha
397 velocity
398 video
399 video data
400 video method
401 video sequences
402 video storage
403 video tape
404 view
405 way
406 y coordinates
407 years
408 zone
409 zone evolution
410 schema:name Follow-on Research Activities for the Rensselaer Isothermal Dendritic Growth Experiment
411 schema:recipient N4ba1ef8907c6429b8b1618181c95ade2
412 Nce5d29b09e8f44b2aac8d82c670abcbb
413 sg:person.010720014261.43
414 sg:person.013371002302.98
415 grid-institutes:grid.254514.3
416 grid-institutes:grid.33647.35
417 schema:sameAs https://app.dimensions.ai/details/grant/grant.8747082
418 schema:sdDatePublished 2022-08-04T17:24
419 schema:sdLicense https://scigraph.springernature.com/explorer/license/
420 schema:sdPublisher N68ce03f11791417da4f6a5fb12e25cb3
421 schema:startDate 2000-05-01
422 schema:url https://taskbook.nasaprs.com/Publication/index.cfm?action=public_query_taskbook_content&TASKID=5211
423 sgo:license sg:explorer/license/
424 sgo:sdDataset grants
425 rdf:type schema:MonetaryGrant
426 N4ba1ef8907c6429b8b1618181c95ade2 schema:member sg:person.013371002302.98
427 schema:roleName Co-PI
428 rdf:type schema:Role
429 N50498cf675294571a896554a9a069ca5 schema:name dimensions_id
430 schema:value grant.8747082
431 rdf:type schema:PropertyValue
432 N68ce03f11791417da4f6a5fb12e25cb3 schema:name Springer Nature - SN SciGraph project
433 rdf:type schema:Organization
434 N90270004f0d24c0cb4d51c72a41af97c schema:name nasa_id
435 schema:value NAG8-1696
436 rdf:type schema:PropertyValue
437 Nce5d29b09e8f44b2aac8d82c670abcbb schema:member sg:person.010720014261.43
438 schema:roleName PI
439 rdf:type schema:Role
440 anzsrc-for:08 schema:inDefinedTermSet anzsrc-for:
441 rdf:type schema:DefinedTerm
442 sg:person.010720014261.43 schema:affiliation grid-institutes:None
443 schema:familyName Glicksman
444 schema:givenName Martin
445 rdf:type schema:Person
446 sg:person.013371002302.98 schema:affiliation grid-institutes:None
447 schema:familyName Koss
448 schema:givenName M.
449 rdf:type schema:Person
450 grid-institutes:None schema:name College of the Holy Cross
451 Rensselaer Polytechnic Institute
452 rdf:type schema:Organization
453 grid-institutes:grid.238252.c schema:Organization
454 grid-institutes:grid.254514.3 schema:Organization
455 grid-institutes:grid.33647.35 schema:Organization
 




Preview window. Press ESC to close (or click here)


...