Time is up.

I only can hope at this piont

hope (third-person singular simple present hopes,

present participle hoping,

simple past and past participle hoped)

(intransitive, transitive) To want something to happen, with a sense of expectation that it might.

Who peed on the floor?

There seems to be a big ring mark left over...

The coffee ring effect occurs when a droplet of a suspension evaporates on a substrate; this process can separate suspended nanoparticles (NPs) by size as a result of geometric constraints at the contact line of the evaporating droplet.

Compared with atmospheric spray pyrolysis, low-pressure spray pyrolysis (LPSP) has a unique capability of producing nanoparticles from micron-sized droplets (Fisenko et al. 2006).

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In physics, a "coffee ring" is a pattern left by a puddle of particle-laden liquid after it evaporates. The phenomenon is named for the characteristic ring-like deposit along the perimeter of a spill of coffee. It is also commonly seen after spilling red wine. The mechanism behind the formation of these and similar rings is known as the coffee ring effect or in some instances, the coffee stain effect, or simply ring stain.

Convective deposition can control particle orientation, resulting in the formation of crystalline monolayer films from nonspherical particles such as hemispherical, dimer, and dumbbell shaped particles. Orientation is afforded by the system trying to reach a state of maximum packing of the particles in the thin meniscus layer over which evaporation occurs.

They showed that tuning the volume fraction of particles in solution will control the specific location along the varying meniscus thickness at which assembly occurs. Particles will align with their long axis in- or out-of-plane depending on whether or not their longer dimension of the particle was equal to the thickness of the wetting layer at the meniscus location.

Such thickness transitions were established with spherical particles as well. It was later shown that convective assembly could control particle orientation in assembling multi-layers, resulting in long-range 3D colloidal crystals from dumbbell shaped particles. These finds were attractive for the self-assembled of colloidal crystal films for applications such as photonics. Recent advances have increased the application of coffee-ring assembly from colloidal particles to organized patterns of inorganic crystals.