We have analyzed a displacement of lung tissues induced by aspiration and expressed it by a phenomenologically derived ellipsoidal harmonics for time course of craniocaudal displacement for a cycle of aspiration. A fitting of the equation to 4DCT images for a pair of lung of five individuals was used for the analysis of the displacement. The observed data were fitted well to the phenomenological equation. The positional dependence of the fitting parameters was reasonably explained. It is suggested that the parameter that denotes the width of the expiration phase could be used to evaluate the validation of the respiratory-gated imaging technique in irradiation therapy for each patient.
A photoreactive fluid is fascinating in a wide range of technological applications because of holding the promise of contactless flow control. The drag-reducing (DR) effects of photorheological fluids composed of nonionic surfactant [oleyldimethylamineoxide (ODMAO)] and photoreactive additives [ortho-methoxycinnamic acid (OMCA)] were investigated by measuring the pressure drop and flow rate in pipe flows. The concentration of ODMAO solution was 500 ppm by weight, the solution temperature was 20 ºC, and the molar ratio of trans-OMCA to ODMAO was varied from 0.2 to 1.0. The time variation of DR effects of photorheological fluids due to the UV irradiation was most obviously observed at the molar ratio of 0.8, which might be caused by the photoisomerization from trans-OMCA to cis-OMCA and corresponded to the variation of the shear viscosity.
Poiseuille's law predicts the stationary flows of fluids between two solid surfaces. Here we use an approximate treatment to predict the velocity fields at the flow front when a fluid is introduced to the space between solid surfaces. Our theory predicts that the velocity of fluids in the flowing direction decreases, while the velocity in the perpendicular direction increases, as one moves from the bulk to the free surface. This theory predicts an analytical expression of the traveling time, destination, and trajectory of fluid particles that flow through the flow front region and these may be accessible by quantitative measurements. Our theory may be useful to treat the dynamics of soft matters that fill the space between solid surfaces.
Although not frequently discussed, the orientational cross-correlation (OCC) has a non-negligible contribution to the stress relaxation of entangled polymers. The origin of OCC has been conjectured to be a coupling in the chain dynamics through the excluded volume interactions, but it has not been revealed yet. In this study, the OCC contribution was measured in the primitive chain network simulations in which the excluded volume interaction is not explicitly implemented, but the density fluctuation of the system is controlled via the phenomenological osmotic force. It was found that the OCC contribution increases with increasing the intensity of osmotic force. This result suggests the significance of the dynamical constraint among the chains due to incompressibility.