[en] Stable suspension of the nanoparticles in the base fluids is inevitable to have the nanofluids be operated properly. Here we report the theoretical model to find the critical size of aggregates in nanofluids for the first time. The concept of relaxation time r_τ is adopted, which reflects the probability of encountering the particles. The hydrodynamic diameter of the aggregates in nanofluids must be kept below the critical size to be stably suspended, which is in good agreement with the experimental results.

[en] Achieving periodicity and size uniformity of quantum dots is significant in improving the performance of quantum dot based devices. An efficient way to control the size and arrangement of quantum dots is to employ a patterned substrate in quantum dot growth. In this paper, the composition, position and shape transition of quantum dots are considered to obtain the minimum energy of the system. The least-energy principle is used here to estimate the critical size of the patterned substrate for single quantum dot growth. Numerical results are in good agreement with experiment, which can help one to control the arrangement of quantum dots by projection of the patterned substrate

[en] Published in summary form only

[en] It was shown that the thermoelastic martensite transformation B2 → B19 inside nanoparticles surrounded by amorphous matrix in Ni-Ti-Cu alloys as well as the non-thermoelastic one γ → α inside nanoparticles surrounded by amorphous matrix in Fe-Ni-B alloys occurred starting with the greatest size fraction. A critical size at which the martensite transformation was suppressed was found to exist on cooling. It was suggested that the essential difference between the critical size for Ni-Ti-Cu and Fe-Ni-B alloys is due to the different types of martensite transformation. The experimental results are in good agreement with theoretical predictions

[en] Work accomplished in support of nonweapons programs by LASL Group Q-14 is described. Included are efforts in basic critical measurements, nuclear criticality safety, a plasma core critical assembly, and reactivity coefficient measurements

No abstract available

[en] Highly accurate critical dimensions for slabs and spheres based on a fully-coupled two-group model are presented for several data sets, covering a wide range of critical sizes. The results were obtained through application of the F_N method, and verify earlier results computed from an analytical solution based on Case's method. These results should be quite useful to code developers in their own right, and this work opens the possibility of multi-group benchmark solutions in slabs, spheres, and cylinders

[en] We investigate the collective synchronization of cicada chirping. Using both experimental and phenomenological numerical techniques, here we show that the onset of a periodic two-state acoustic synchronous behavior in cicada chorus depends on a critical size of population N_c = 21, above which a typical chorus state appears periodically with a 30 second-silence state in between, and further clarify its possibility concerning a new class of phase transition, which is unusually driven by population. This work has relevance to acoustic synchronization and to general physics of phase transition. (general)

[en] Micromagnetic states are strongly related to sizes of nano-dots. The quasiuniform state becomes unstable and transforms to a new nonuniform state as the diameter of the permalloy circular dot exceeds some critical size. The magnetization curvature increases gradually as the diameter increases. Finally, when the diameter is larger than another critical size, the new nonuniform state becomes unstable and a vortex enters the particle. Hence the new nonuniform state plays an intermediate role in the evolution from the quasiuniform state to the vortex state as the diameter increases

[en] Despite recent advances in monitoring nucleation from a vapor at close-to-molecular resolution, the identity of the critical cluster, forming the bottleneck for the nucleation process, remains elusive. During past twenty years, the first nucleation theorem has been often used to extract the size of the critical cluster from nucleation rate measurements. However, derivations of the first nucleation theorem invoke certain questionable assumptions that may fail, e.g., in the case of atmospheric new particle formation, including absence of subcritical cluster losses and heterogeneous nucleation on pre-existing nanoparticles. Here we extend the kinetic derivation of the first nucleation theorem to give a general framework to include such processes, yielding sum rules connecting the size dependent particle formation and loss rates to the corresponding loss-free nucleation rate and the apparent critical size from a naïve application of the first nucleation theorem that neglects them