@article{BaibolatovSpahn2012,
  author    = {Baibolatov, Yernur and Spahn, Frank},
  title     = {The role of adhesion for ensembles of mesoscopic particles},
  series = {Granular matter},
  volume    = {14},
  journal   = {Granular matter},
  number    = {2},
  publisher = {Springer},
  address   = {New York},
  issn      = {1434-5021},
  doi       = {10.1007/s10035-012-0325-4},
  pages     = {197 -- 202},
  year      = {2012},
  abstract  = {We present a toy-model for an ensemble of adhering mesoscopic constituents in order to estimate the effect of the granular temperature on the sizes of embedded aggregates. The major goal is to illustrate the relation between the mean aggregate size and the granular temperature in dense planetary rings. For sake of simplicity we describe the collective behavior of the ensemble by means of equilibrium statistical mechanics, motivated by the stationary temperature established by the balance between a Kepler-shear driven viscous heating and inelastic cooling in these cosmic granular disks. The ensemble consists of N' equal constituents which can form cluster(s) or move like a gas-or both phases may coexist-depending on the (granular) temperature of the system. We assume the binding energy levels of a cluster E-c = -N-c gamma a to be determined by a certain contact number N-c, given by the configuration of N constituents of the aggregate (energy per contact: -gamma a). By applying canonical and grand-canonical ensembles, we show that the granular temperature T of a gas of constituents (their mean kinetic energy) controls the size distribution of the aggregates. They are the smaller the higher the granular temperature T is. A mere gas of single constituents is sustained for T >> gamma a. In the case of large clusters (low temperatures T << gamma a) the size distribution becomes a Poissonian.},
  language  = {en}
}
@phdthesis{FernandesGuimaraes2012,
  author    = {Fernandes Guimar{\~a}es, Ana Helena},
  title     = {How does adhesion influence the small aggregates in Saturn's rings},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-61846},
  school      = {Universit{\"a}t Potsdam},
  year      = {2012},
  abstract  = {Particles in Saturn's main rings range in size from dust to even kilometer-sized objects. Their size distribution is thought to be a result of competing accretion and fragmentation processes. While growth is naturally limited in tidal environments, frequent collisions among these objects may contribute to both accretion and fragmentation. As ring particles are primarily made of water ice attractive surface forces like adhesion could significantly influence these processes, finally determining the resulting size distribution. Here, we derive analytic expressions for the specific self-energy Q and related specific break-up energy Q⋆ of aggregates. These expressions can be used for any aggregate type composed of monomeric constituents. We compare these expressions to numerical experiments where we create aggregates of various types including: regular packings like the face-centered cubic (fcc), Ballistic Particle Cluster Aggregates (BPCA), and modified BPCAs including e.g. different constituent size distributions. We show that accounting for attractive surface forces such as adhesion a simple approach is able to: a) generally account for the size dependence of the specific break-up energy for fragmentation to occur reported in the literature, namely the division into "strength" and "gravity" regimes, and b) estimate the maximum aggregate size in a collisional ensemble to be on the order of a few meters, consistent with the maximum aggregate size observed in Saturn's rings of about 10m.},
  language  = {en}
}