The release of two compositionally different solutes from a composite gel composed of two different populations of microgel particles embedded in a single bulk gel matrix is described, showing the potential of the "plum-pudding gel" as a multifunctional platform for controlled surface release. One hydrophobic solute (pyrene) and one hydrophobic and charged solute (rhodamine 123) were chosen as the solutes to be released. Hydrophobic microgels composed of 50% N-isopropylacrylamide (NIPAM) and 50% N-tert-butylacrylamide (BAM) were loaded with pyrene, and anionic microgels composed of 30% acrylic acid (AAc), 20% NIPAM, and 50% BAM were loaded with rhodamine 123. The two solute-loaded microgel populations were incorporated into a single bulk gel network, from which the two solutes were released simultaneously and independently. Using this structural motif, solutes that are mutually incompatible can be incorporated into a single matrix with which they may also be incompatible. The electrostatically incorporated solute was released much more slowly than the hydrophobically attracted solute, indicating that the microgel composition can be tailored to the specific solute, and thus control its release rate. The choice of bulk matrix was also found to influence the release rate much more than expected, offering a further control element to the system.

We analyze heat and work fluctuations in the gravitational wave detector AURIGA, modeled as a macroscopic electromechanical oscillator in contact with a thermostat and cooled by an active feedback system. The oscillator is driven to a steady state by the feedback cooling, equivalent to a viscous force. The experimentally measured fluctuations are in agreement with our theoretical analysis based on a stochastically driven Langevin system. The asymmetry of the fluctuations of the absorbed heat characterizes the oscillator's nonequilibrium steady state and reveals the extent to which a feedback cooled system departs from equilibrium in a statistical mechanics perspective.

We study the onset of the bootstrap percolation transition as a model of generalized dynamical arrest. Our results apply to two dimensions, but there is no significant barrier to extending them to higher dimensionality. We develop a new importance-sampling procedure in simulation, based on rare events around "holes", that enables us to access bootstrap lengths beyond those previously studied. By framing a new theory in terms of paths or processes that lead to emptying of the lattice we are able to develop systematic corrections to the existing theory and compare them to simulations. Thereby, for the first time in the literature, it is possible to obtain credible comparisons between theory and simulation in the accessible density range.

We introduce an order parameter for dynamical arrest. Dynamically available volume (unoccupied space that is available to the motion of particles) is expressed as holes for the simple lattice models we study. Near the arrest transition the system is dilute in holes, so we expand dynamical quantities in a series of hole density. Unlike the situation when presented in particle density, all cases of simple models that we examine have a quadratic dependence of the diffusion constant on hole density. This observation implies that in certain regimes ideal dynamical arrest transitions may possess a hitherto unnoticed degree of universality.