Characterization of Advanced Aluminum Titanate Ceramic Filter Having Hexagonal Cell Geometry

Aluminum titanate (AT)-based Diesel Particulate Filter (DPF) with hexagonal cell geometry has previously been presented as a promising media showing extremely lower pressure drop, coming from its specific hexagonal channels of DPF. In addition these AT characteristics, the investigation on an engine bench verified that AT filter with the hexagonal cell structure exhibited different combustion behavior from the one with the standard cell structure. To understand this behavior, direct observation inside the filter on its microscopic scale was carried out. It was found that the hexagonal channels induced multiple steps on particulate matter accumulation

Flow Analysis during Soot Trapping on Aluminum Titanate Ceramics Filter with Hexagonal Cell Geometry

The phenomena of soot trapping and oxidation in a hexagonal cell geometry DPF made of aluminum titanium oxide were investigated through microscopic visualization experiment and a simple analysis based on Darcy’s law through the wall and the deposited soot layer. There were two types of flow: one was a flow through a wall between inlet and outlet channels (inlet/outlet wall flow), and the other was a flow which was introduced into a wall between inlet and inlet channels, and was turned toward the direction parallel to the wall, and finally exited into the outlet channel (bypass flow). The flow rate of the bypass flow was increased with a thickness of soot layer deposited on the inlet/outlet wall. As a result, the soot was trapped even on the inlet/inlet wall surface. In the regeneration process, depending on the flow rate of the bypass flow, the maximum temperature for the hexagonal cell DPF became lower compared with that for the conventional DPF

Dental undergraduates' smoking status and social nicotine dependence in Japan and Taiwan - comparison between two dental schools

Objectives: Smoking behaviour persisted due to psychological and physical dependence. A questionnaire, "the Kano Test for Social Nicotine Dependence (KTSND)", has been developed to assess the persistence of tobacco use. This study aimed to investigate into the prevalence and factors of smoking in a sample of dental undergraduates in Japan and Taiwan. A special interest was to establish the association between gender, smoking status, relationship with smokers, as well as baseline and after-lecture KTSND scores. Methods: One hundred and thirty 4th year and forty-one 5th year dental undergraduates at the Aichi Gakuin University (AU, Japan; 85 males and 45 females; 21.7 ± 1.7 years) and the Kaohsiung Medical University (KU, Taiwan; 27 males and 14 females; 24.1 ± 2.1 years) were invited to participate, respectively. Each was assessed with a KTSND questionnaire before and after attending a tobacco-control educational programme. Results: Thirty-five smokers (20.5%, AU: 34, KU: 1), nine ex-smokers (5.2%, AU: 8, KU: 1) and 127 non-smokers (74.3%) were included. The prevalence of inhalation of second-hand smoke at home was 30.0% (39 students) and 18.2% (6 students) in Japan and Taiwan, separately. Japanese students showed a higher total KTSND score than Taiwanese (13.3 ± 6.4; 10.2 ± 4.9, P < 0.01). Attendance of the tobacco-control educational programme contributed to a decrease in the total KTSND score from 12.6 ± 6.2 to 7.7 ± 5.7. The total KTSND scores among smokers (17.4 ± 6.2) and ex-smokers (14.6 ± 4.5) were significantly higher than non-smokers' (11.1 ± 5.7) (P < 0.01). In Taiwan, male students demonstrated higher KTSND scores than their counterparts (11.3 ± 5.0; 8.1 ± 3.9, P < 0.05). Conclusion: The prevalence of smoking and the total KTSND scores among dental undergraduates were higher in Japan than in Taiwan. The total KTSND score was related to smoking status. Attendance of a tobacco-control educational programme decreased the total KTSND score. Future popularisation in the type of educational programme is indicated