The primary nucleation step in amyloid fibril formation can, depending on the nature of peptide sequence, occur in one step, straight from a dilute solution, or in multiple steps, via oligomers or disordered aggregates. The precise kinetic pathways of these processes are poorly understood. Employing forward flux sampling and a midresolution coarse-grained force field, we analyzed the reactive p...

Mechanisms for the formation of Type I (nitric acid-based) polar stratospheric louds (PSCs) are discussed. If the pre-existing sulfate aerosols are liquid prior to PSC formation, then nitric acid particles (Type Ib) form by HNO 3 dissolution in aqueous H2SO,• solution droplets. This process does not require a nucleation step for the formation of HNO3 aerosols, so most pre-existing aerosols grow...

Ice nucleation is the crucial step for ice formation in atmospheric clouds and therefore underlies climatologically relevant precipitation and radiative properties. Progress has been made in understanding the roles of temperature, supersaturation, and material properties, but an explanation for the efficient ice nucleation occurring when a particle contacts a supercooled water drop has been elu...

A numerical modeling study is presented concerning the role of total pressure in gas-phase nucleation. We consider a generic self-clustering mechanism for particle production in which the cluster transport properties are assumed to scale with monomer properties. A steady-state isothermal plug flow reactor model is considered in which axial diffusion of gas species is allowed. Species conservati...

Understanding and controlling nucleation is important for many crystallization applications. Calcium carbonate (CaCO3) is often used as a model system to investigate nucleation mechanisms. Despite its great importance in geology, biology, and many industrial applications, CaCO3 nucleation is still a topic of intense discussion, with new pathways for its growth from ions in solution proposed in ...

Most of the nanoparticle number emissions from diesel engines are found in the nucleation mode (Dp<∼ 30 nm). These nanoparticles are mainly formed by nucleation as diesel engine exhaust gas cools and dilutes in the atmosphere. Diesel nanoparticles have raised concerns because of their suspected human health effects. There are two main theories describing diesel nanoparticle nucleation: homogene...

Clathrate hydrates are solid crystalline structures most commonly formed from solutions that have nucleated to form a mixed solid composed of water and gas. Understanding the mechanism of clathrate hydrate nucleation is essential to grasp the fundamental chemistry of these complex structures and their applications. Molecular dynamics (MD) simulation is an ideal method to study nucleation at the...