Large-Eddy Simulation of Pollutant Removal from a Three-Dimensional Street Canyon   总被引：3，自引：3，他引：0  

Takenobu Michioka  Hiroshi Takimoto  Ayumu Sato 《Boundary-Layer Meteorology》2014,150(2):259-275

Large-eddy simulations were conducted to investigate the mechanism of pollutant removal from a three-dimensional street canyon. Five block configurations with aspect ratios (building height to length) of 1, 2, 4, 8 and $\infty $ were used to create an urban-like array. A pollutant was released from a ground-level line source at the centre of the target canyon floor. For smaller aspect ratios, the relative contribution of the turbulent mass flux to net mass flux at the roof level, which was spatially averaged along the roof-level ventilation area, was closer to unity, indicating that turbulent motions mainly affected pollutant removal from the top of the canyon. As aspect ratio increased, the relative contribution became smaller, owing to strong upwind motions. However, the relative contribution again reached near unity for the infinite aspect ratio (i.e. a two-dimensional street canyon) because of lowered lateral flow convergence. At least 75 % of total emissions from the three-dimensional street canyon were attributable to turbulent motions. Pollutant removal by turbulent motions was related to the coherent structures of low-momentum fluid above the canyons. Though the coherent structure size of the low-momentum fluid differed, the positions of low-momentum fluid largely corresponded to instantaneous high concentrations of pollutant above the target canyon, irrespective of canyon geometry.  相似文献   

Characteristics of Triassic epithermal Au mineralization at the Q prospect,Chatree mining area,Central Thailand     

Ladda Tangwattananukul  Daizo Ishiyama  Osamu Matsubaya  Toshio Mizuta  Punya Charusiri  Hinako Sato  Koichiro Sera 《Resource Geology》2014,64(2):167-181

The Chatree deposit is located in the Loei‐Phetchabun‐Nakhon Nayok volcanic belt that extends from Laos in the north through central and eastern Thailand into Cambodia. Gold‐bearing quartz veins at the Q prospect of the Chatree deposit are hosted within polymictic andesitic breccia and volcanic sedimentary breccia. The orebodies of the Chatree deposit consist of veins, veinlets and stockwork. Gold‐bearing quartz veins are composed mainly of quartz, calcite and illite with small amounts of adularia, chlorite and sulfide minerals. The gold‐bearing quartz veins were divided into five stages based on the cross‐cutting relationship and mineral assemblage. Intense gold mineralization occurred in Stages I and IV. The mineral assemblage of Stages I and IV is characterized by quartz–calcite–illite–laumontite–adularia–chlorite–sulfide minerals and electrum. Quartz textures of Stages I and IV are also characterized by microcrystalline and flamboyant textures, respectively. Coexistence of laumontite, illite and chlorite in the gold‐bearing quartz vein of Stage IV suggests that the gold‐bearing quartz veins were formed at approximately 200°C. The flamboyant and brecciated textures of the gold‐bearing quartz vein of Stage IV suggest that gold precipitated with silica minerals from a hydrothermal solution that was supersaturated by boiling. The δ¹⁸O values of quartz in Stages I to V range from +10.4 to +11.6‰ except for the δ¹⁸O value of quartz in Stage IV (+15.0‰). The increase in δ¹⁸O values of quartz at Stage IV is explained by boiling. P_H2O is estimated to be 16 bars at 200°C. The f_CO2 value is estimated to be 1 bar based on the presence of calcite in the mineral assemblage of Stage IV. The total pressure of the hydrothermal solution is approximately 20 bars at 200°C, suggesting that the gold‐bearing quartz veins of the Q prospect formed about 200 m below the paleosurface.  相似文献   

ISRM Suggested Method for the Needle Penetration Test   总被引：1，自引：0，他引：1  

Resat Ulusay  Ömer Aydan  Zeynal A. Erguler  Dominique J. M. Ngan-Tillard  Takafumi Seiki  Wim Verwaal  Yasuhito Sasaki  Akira Sato 《Rock Mechanics and Rock Engineering》2014,47(3):1073-1085

  相似文献   

A procedure for tidal analysis with a Bayesian information criterion   总被引：16，自引：0，他引：16  

Y. Tamura  T. Sato  M. Ooe  M. Ishiguro 《Geophysical Journal International》1991,104(3):507-516

  相似文献   

Infrared polarimetry of the stars in the inner galaxy     

Y. Kobayashi  J. Jugaku  H. Okuda  S. Sato  T. Nagata 《Astrophysics and Space Science》1986,119(1):135-139

  相似文献   

Global shearing modes of galactic disks     

Masanori Iye  Tatsuo Ueda  Masafumi Noguchi  Shinko Aoki 《Astrophysics and Space Science》1983,89(2):363-376

A new scheme has been devised to calculate discrete unstable global shearing spiral modes of gaseous disk models of galaxies. The scheme makes use of the Legendre expansion of eigen functions and the problem of stability analysis is reduced to an eigenvalue problem of an infinite matrix. The spiral patterns of these shearing wave solutions of linearized equations change their form in the course of time due to the differential rotation of the equilibrium disk. These shearing wave solutions are presumed to have intermediate characteristics between so-called density-waves and material arms. Comparison between these shearing modes and the non-shearing normal modes for a series of disk models is presented.  相似文献   

红外相机CASCAM光学设计   总被引：1，自引：1，他引：0  

季春宏  姚永强  长岛千惠  佐藤修二 《天文学报》2003,44(4):390-404

介绍紫金山天文台研制的光学-近红外相机CASCAM（Chinese Academy of Science，CAMera)的光学系统设计．CASCAM相机以红外列阵HAWAII-1和光学CCD为探测器，配备国家天文台兴隆观测站2．16米和1．26米望远镜进行0．4—2．5μm波长范围的成像和偏振成像观测．相机的光学系统由F／9→F／6缩焦系统和Offner反射成像系统构成．优化设计结果表明，光学设计方案已满足天文观测的要求．CASCAM相机在设计上实现了光学-近红外很宽波段的消色差变焦，并在楔形分柬片、常温滤光片轮和折射式焦面摆动技术等方面进行了新的尝试．  相似文献   

A dislocation model for the earthquake cycle at convergent plate boundaries   总被引：1，自引：0，他引：1  

Mitsuhiro Matsu'ura  Toshinori Sato 《Geophysical Journal International》1989,96(1):23-32

  相似文献   

Is the periodicity in the distribution of quasar redshifts evidence for the universe being multiply-connected ?     

Humitaka Sato 《Chinese Astronomy and Astrophysics》1984,8(2):148-150

If the cosmological space is a topolegically compactified manifold, e.g. a three-dimensional torus, then the periodicity in the distribution of quasar redshifts can be explained. The present scale of such a compactified space is estimated to be on the order of 600 Mpc.  相似文献   

Scale factor calibration of a superconducting gravimeter at Esashi Station, Japan, using absolute gravity measurements     

Y. Tamura  T. Sato  Y. Fukuda  T. Higashi 《Journal of Geodesy》2005,78(7-8):481-488

The scale factor of a superconducting gravimeter (SG) at the Esashi Earth Tides Station, Japan, was revised by repeating co-located absolute gravity measurements with an FG5 gravimeter. Although the calibration results from the absolute gravimeter (AG) show an apparent secular change in the scale factor of the SG (0.4% for the period 1993–2002), the relative scale factors, which are determined by tidal analysis with the response method, indicate that it has changed by no more than 0.01% during the above period. If the mean scale factor over the 10 years is adopted, a value of –56.082±0.029 Gal/V (1 Gal =10^–8 m s^–2) is obtained, which is about 0.4% smaller than that used in the global geodynamics project (GGP) database. Based on this newly determined scale factor, the tidal gravity factors at Esashi have been re-estimated. The observed tidal factors, corrected for the ocean tide effects with recent models, indicate that the theoretical gravity factors for an inelastic Earth model are more consistent with the observations than are those for an elastic model.  相似文献