We present a new method, the analytical rebridging scheme, for Monte Carlo simulation of proline-containing, cyclic peptides. The cis/trans isomerization is accommodated by allowing for two states of the amide bond. We apply our method to five peptides that have previously been characterized by NMR methods. Our simulations achieve effective equilibration and agree well with experimental data in all cases. We discuss the importance of effective equilibration as well as the role of bond flexibility and solvent effects in the prediction of equilibrium properties.Submitted to J. Chem. Phys.

A biased Monte Carlo scheme for zeolite structure solutionAn atomic-scale model for silicate solutions is introduced for investigation of the nucleation process during zeolite synthesis in the absence of a structure directing agent. Monte Carlo schemes are developed to determine the equilibrium distribution of silicate cluster sizes within the context of this model. How the nucleation barrier and critical cluster size change with Si monomer concentration is discussed. Distance and angle histograms as well as ring size distributions are calculated and compared with known zeolite structures. The free energies of critical clusters are compared with those for small clusters of ␣-quartz.

We present a new, biased Monte Carlo scheme for simulating complex, cyclic peptides. Backbone atoms are equilibrated with a biased rebridging scheme, and side-chain atoms are equilibrated with a look-ahead configurational bias Monte Carlo. Parallel tempering is shown to be an important ingredient in the construction of an efficient approach.

A Human-In-The-Loop air traffic control simulation investigated the impact of uncertainties in trajectory predictions on NextGen Trajectory-Based Operations concepts, seeking to understand when the automation would become unacceptable to controllers or when performance targets could no longer be met. Retired air traffic controllers staffed two en route transition sectors, delivering arrival traffic to the northwest corner-post of Atlanta approach control under time-based metering operations. Using trajectory-based decisionsupport tools, the participants worked the traffic under varying levels of wind forecast error and aircraft performance model error, impacting the ground automation's ability to make accurate predictions. Results suggest that the controllers were able to maintain high levels of performance, despite even the highest levels of trajectory prediction errors.

The synthesis, structure solution, and characterization of the high-silica zeolite SSZ-55 are described. SSZ-55 was synthesized under hydrothermal conditions using a [(1-(3-fluorophenyl)cyclopentyl)methyl]trimethylammonium cation as the structure-directing agent. The framework topology and symmetry of SSZ-55 were determined by the Monte Carlo method ZEFSAII. Rietveld refinement of the X-ray powder diffraction data confirms the space group assignment of Cmc2 1 . Transmission electron microscopy confirms the unit cell parameters and the topology of the structure. SSZ-55 contains one-dimensional pores circumscribed by 12 T-atom rings. The topology of SSZ-55 is that of the ATS framework, previously described for AlPO-based molecular sieves.