Abstract: Nanoscale thermites such as the composite mixture of
nano-sized aluminum and molybdenum trioxide powders possess
several technical advantages such as much higher reaction rate and
shorter ignition delay, when compared to the conventional energetic
formulations made of micron-sized metal and oxidizer particles. In this
study, the self-propagation of combustion wave in compacted pellets
of nanoscale thermite composites is modeled and computationally
investigated by utilizing the activation energy reduction of aluminum
particles due to nanoscale particle sizes. The present computational
model predicts the speed of combustion wave propagation which is
good agreement with the corresponding experiments of thermite
reaction. Also, several characteristics of thermite reaction in nanoscale
composites are discussed including the ignition delay and combustion
wave structures.
Abstract: Viscous heating becomes significant in the high speed
resin coating process of glass fibers for optical fiber manufacturing.
This study focuses on the coating resin flows inside the capillary
coating die of optical fiber coating applicator and they are numerically
simulated to examine the effects of viscous heating and subsequent
temperature increase in coating resin. Resin flows are driven by fast
moving glass fiber and the pressurization at the coating die inlet, while
the temperature dependent viscosity of liquid coating resin plays an
important role in the resin flow. It is found that the severe viscous
heating near the coating die wall profoundly alters the radial velocity
profiles and that the increase of final coating thickness by die
pressurization is amplified if viscous heating is present.
Abstract: R&D risk management has been suggested as one of
the management approaches for accomplishing the goals of public
R&D investment. The investment in basic science and core technology
development is the essential roles of government for securing the
social base needed for continuous economic growth. And, it is also an
important role of the science and technology policy sectors to generate
a positive environment in which the outcomes of public R&D can be
diffused in a stable fashion by controlling the uncertainties and risk
factors in advance that may arise during the application of such
achievements to society and industry. Various policies have already
been implemented to manage uncertainties and variables that may
have negative impact on accomplishing public R& investment goals.
But we may derive new policy measures for complementing the
existing policies and for exploring progress direction by analyzing
them in a policy package from the viewpoint of R&D risk
management.