Nagoya Institute of Technology

About: Nagoya Institute of Technology is a education organization based out in Nagoya, Japan. It is known for research contribution in the topics: Thin film & Catalysis. The organization has 10766 authors who have published 19140 publications receiving 255696 citations. The organization is also known as: Nagoya Kōgyō Daigaku & Nitech.

Modeling of flame-generated turbulence based on direct numerical simulation databases

Abstract: Turbulent premixed flames propagating in homogeneous isotropic turbulent flows were simulated directly with a single-step irreversible reaction. Two cases were calculated, case H, with a high-density ratio of flame pu/pb=7.53, and case L, low-density ratio of flame pu/pb=2.50, while u′/uL was nearly equal to unity. We obtained databases of fully developed stationary turbulent flames. These databases were investigated by analyzing the transport equation for turbulent kinetic energy to study flame-generated turbulence and its models. We found that turbulent fluctuations of all components, especially the streamwise component, were amplified in the flame brush and that flame-generated turbulence increased for a larger density ratio of the flame. Analysis based on the Favre-averaged transport equation for turbulent kinetic energy showed that pressure-related terms produced kinetic energy in the flame brush, the mean pressure gradient term was most important in case H and the pressure work term was most important in case L. On the other hand, the diffusion and dissipation term and velocity gradient term decreased kinetic energy. Next, modeling of the important terms in the balance equations were discussed. The mean pressure gradient term, pressure dilatation term, and additional dissipation components were modeled and compared with the direct numerical simulation (DNS) results. The mean pressure gradient term was modeled with assumption on the density, and the model was in good agreement with DNS. The other two terms were also modeled by scaling and these models mimicked DNS well.

Defect imaging with guided waves in a pipe

Abstract: Guided wave techniques are expected to become an effective means for rapid, long-range inspection of pipes. Such techniques still have many practical difficulties in application, however, due to the complex characteristics of guided waves such as dispersion and their multimodal nature. A defect imaging technique is developed in this study to overcome the complexities of guided wave inspection. Received signals are separated into single-mode waveforms with a mode extraction technique and then spatial waveforms on the pipe surface at an arbitrary time are reconstructed. The predicted waveforms can provide a defect image at the moment when an incident wave arrives at a defect region, which is based on a time-reversal technique. This defect imaging technique is experimentally verified using eight signals detected at eight different circumferential positions. Images of artificial defects are obtained with one-hole and two-hole test pipes, and increasing the frequency of incident waves increases the resolution of the images. Holes and pipe ends are recognizable in the images, but the reconstructed images contain some errors in the area behind the defects where guided waves do not propagate or do not reflect back to the receiving transducers.

Catalytic Enantioselective Allylation of Ketimines by Using Palladium Pincer Complexes with Chiral Bis(imidazoline)s

Abstract: Get selective! Enantioselective allylation of ketimines derived from isatins by using chiral 1,3-bis(imidazolin-2-yl)benzene (Phebim)-Pd(II) complexes afforded products with good enantioselectivity (see scheme). The reaction was applied to a wide variety of ketimines. The obtained product can be converted to homoallylic amines and a spirocyclic amine without the loss of enantiopurity.