scholarly journals Equilibrium neck shapes for initial stages of solid-state sintering due to surface diffusion in a disk model of clays

2011 ◽  
Vol 43 (2) ◽  
pp. 133-143 ◽  
Author(s):  
I. Medved ◽  
J. Moravcíková
Keyword(s):  
Free Energy ◽  
Solid State ◽  
Surface Diffusion ◽  
Surface Free Energy ◽  
Anisotropy Parameter ◽  
Microscopic Model ◽  
Disk Model ◽  
Solid State Sintering ◽  
Uniform Disk ◽  
Simplified Form

We study equilibrium neck shapes corresponding to initial stages of solid-state sintering, using a microscopic model of clays in which particles have a uniform disk shape with a microscale diameter R and a nanoscale thickness ? = R/100. Particles are stacked on top of each other, forming vertical piles of various heights ranging from h = ? to h = 10?. Pores are formed in the spaces between any three touching piles of the same height. Assuming that surface diffusion is the dominant sintering mechanism and considering a simplified form of the neck configuration, we derive equilibrium neck shapes by minimizing a neck surface free energy when a neck volume V fixed. We allow for the anisotropy of the surface free energy, using a single anisotropy parameter q. We discuss the dependence of the obtained neck shapes on the neck volume V, pore height h, and anisotropy parameter q.

scholarly journals Viscosity and surface-free energy effects in thermal shrinking of solid-state nanopores

2012 ◽  
Vol 100 (23) ◽  
pp. 233107 ◽  
Author(s):  
Joseph A. Billo ◽  
Jared Jones ◽  
Waseem Asghar ◽  
Ronald L. Carter ◽  
Samir M. Iqbal
Keyword(s):  
Free Energy ◽  
Solid State ◽  
Surface Free Energy

scholarly journals Fabrication of Molecular Micro-NanoStructures by Surface-Tension-Driven Technique

2007 ◽  
Vol 1002 ◽  
Author(s):  
Ilenia Viola ◽  
Fabio Della Sala ◽  
Manuel Piacenza ◽  
Laura Favaretto ◽  
Massimo Gazzano ◽  
...  
Keyword(s):  
Surface Tension ◽  
Free Energy ◽  
Solid State ◽  
Surface Free Energy ◽  
Liquid Solution ◽  
Conformational Flexibility ◽  
Molecular Aggregation ◽  
Molecular Materials ◽  
Dewetting Process ◽  
Structural Arrangement

We present the fabrication of a pixels structure by a well-defined pattern replication of a micrometer template driven by a surface free-energy lithographic technique, realized by molecular aggregation in dewetting conditions and by confining the liquid solution with geometric boundaries. The organization in the solid-state of the selected thiophene-based molecular materials allows to realize a bicoloured, green and red-emitting pixels structure, by exploiting the molecular structural arrangement, induced during a dewetting process, and the great conformational flexibility of DTT7Me.

scholarly journals Impact of Hot-Melt-Extrusion on Solid-State Properties of Pharmaceutical Polymers and Classification Using Hierarchical Cluster Analysis

Processes ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. 1208
Author(s):  
Ioannis Partheniadis ◽  
Miltiadis Toskas ◽  
Filippos-Michail Stavras ◽  
Georgios Menexes ◽  
Ioannis Nikolakakis
Keyword(s):  
Cluster Analysis ◽  
Free Energy ◽  
Solid State ◽  
Surface Free Energy ◽  
Hierarchical Cluster Analysis ◽  
Hierarchical Cluster ◽  
Hot Melt Extrusion ◽  
Electrostatic Charge ◽  
Major Cluster ◽  
Hot Melt

The impact of hot-melt extrusion (HME) on the solid-state properties of four methacrylic (Eudragit® L100-55, Eudragit® EPO, Eudragit® RSPO, Eudragit® RLPO) and four polyvinyl (Kollidon® VA64, Kollicoat® IR, Kollidon® SR, and Soluplus®) polymers was studied. Overall, HME decreased Tg but increased electrostatic charge and surface free energy. Packing density decreased with electrostatic charge, whereas Carr’s and Hausner indices showed a peak curve dependency. Overall, HME reduced work of compaction (Wc), deformability (expressed as Heckel PY and Kawakita 1/b model parameters and as slope S′ of derivative force/displacement curve), and tablet strength (TS) but increased elastic recovery (ER). TS showed a better correlation with S′ than PY and 1/b. Principal component analysis (PCA) organized the data of neat and extruded polymers into three principal components explaining 72.45% of the variance. The first included Wc, S′ and TS with positive loadings expressing compaction, and ER with negative loading opposing compaction; the second included PY, 1/b, and surface free energy expressing interactivity with positive loadings opposing tap density or close packing. Hierarchical cluster analysis (HCA) assembled polymers of similar solid-state properties regardless of HME treatment into a major cluster with rescaled distance Cluster Combine Index (CCI) < 5 and several other weaker clusters. Polymers in the major cluster were: neat and extruded Eudragit® RSPO, Kollicoat® IR, Kollidon® SR, Soluplus®, and extruded Eudragit® L100-55. It is suggested that PCA may be used to distinguish variables having similar or dissimilar activity, whereas HCA can be used to cluster polymers based on solid-state properties and pick exchangeable ones (e.g., for sustain release or dissolution improvement) when the need arises.

Smectic A-Smectic B interface : faceting and surface free energy measurement

1989 ◽  
Vol 50 (24) ◽  
pp. 3527-3534 ◽  
Author(s):  
P. Oswald ◽  
F. Melo ◽  
C. Germain
Keyword(s):  
Free Energy ◽  
Surface Free Energy ◽  
Energy Measurement ◽  
Smectic A

Examination of the lubricant storing and releasing ability of thermally sprayed surfaces

2011 ◽  
Vol 2 (2) ◽  
pp. 101-105
Author(s):  
L. Fazekas ◽  
Z. S. Tiba ◽  
G. Kalácska
Keyword(s):  
Free Energy ◽  
Surface Energy ◽  
Surface Free Energy ◽  
Essential Role ◽  
Index Number ◽  
Adhesion Ability ◽  
Thermally Sprayed ◽  
Proper Operation

Abstract The lubricant storing and releasing ability of the thermally sprayed surfaces plays an essential role in the proper operation of the components. In the case of porous sprayed surfaces the lubricant storing and releasing ability depends mainly on porosity and the surface energy (adhesion susceptibility). The adhesion ability can also be expressed indirectly with an index number that is by determining the surface free energy.

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