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Komang Anggayana Basuki Rahmad H. H. Arie Naftali Agus Haris Widayat 《Journal of the Geological Society of India》2014,83(5):555-562
Samples of early Miocene Muara Wahau coal from three drill cores were investigated with respect to maceral composition. Huminite macerals are dominant in the coal, ranging from 73.3 to 88.0% (vol.) with an average value of 77.4% (vol.). Liptinite macerals account for lower amount, from 0.7 to 6.7 with an average value of 1.8% (vol.). Inertinite macerals vary from 4.3 to 34.0% (vol.), averaging at 15.3% (vol.). Some paleoenvironmental indices based on the maceral composition were determined. Groundwater index (GWI) and vegetation index (VI) were considered as indicators for hydrological regime and type of peat vegetation. Tissue preservation index (TPI) and gelification index (GI) were determined to indicate the degree of preservation and relative wetness of the peat forming conditions. The VI-GWI diagram suggest that the coal was developed from herbaceous plants in ombrotrophic type of peat. TPI-GI diagram shows that the preservation was low and the peat was relatively wet or limnic. However, ombrotrophic peat type have commonly been related to relatively drier or telmatic environments. It is therefore, interpreted that the limnic condition could occur in ombrotrophic peat type, as the water level was rising up during the development of a high moor peat. 相似文献
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Change detection of tooth surface loss in the cervical region of a tooth replica has been performed using a fixed-base stereoscopic camera, consisting of two SLR digital cameras with lenses of fixed focal length. Commercial digital photogrammetric and calibration software was used to perform a convergent multi-station calibration with an artefact comprising a transilluminated planar array and a tiered object exhibiting optical texture. Digital surface models of a tiered test object and a tooth surface containing a non-carious cervical lesion were generated from stereo-imagery. The accuracy of automatic mass point measurement of a planar surface was 4 ± 13 μm in Z. The sensitivity of change detection on mapped tooth replicas was 0·03 mm with change ranging from 0·03 to 0·07 mm per annum. Different rates of change were clearly evident in different areas at different times. The results of this investigation suggest that annual change detection studies will provide a clearer picture of the pattern of tooth surface loss and, in combination with other analytical techniques, a more detailed explanation of the natural history of these lesions. 相似文献
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正常而言,在印度尼西亚的苏门答腊和加里曼丹岛,即使在非厄尔尼诺年,每年6月或7月的旱季会出现烟雾问题。研究发现,近年来烟雾问题并不仅仅出现在旱季,雨季也有发生。进一步的观测和野外调研表明,这些烟雾来源于用火烧的方式进行油棕榈及其它林木种植前的土地整理,然而这种方式早已被完全禁止。结果,这两个省的绝大多数的水灾灾区位于这些植被被焚毁的地区。 相似文献
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Geoffrey D. Smith Robbert Wetselaar James J. Fox Robert H. M. van de Graaff Doeljachman Moeljohardjo Joko Sarwono Wiranto Sri Rahajoe Asj'ari Suharto Tjojudo Basuki 《Hydrogeology Journal》1999,7(6):576-589
The causes and nature of nitrate pollution of wells in a village within Kotagede, a subdistrict of the city of Yogyakarta,
Indonesia, were investigated in a detailed hydrological study. Nitrate concentrations in groundwater frequently exceeded the
WHO recommended limit of 50 mg L − 1. Groundwater nitrate concentrations were measured over a 19-month period in monitoring wells and in piezometers placed strategically
in relation to sewage tanks within the village. Results indicate that the tanks are major sources of nitrate in the groundwater
and that the input is markedly dependent on rainfall, resulting in a surge of nitrate into the groundwater at the beginning
of each wet season. That the tanks are a major source was confirmed by measuring nitrate in soil cores obtained by augering
close to selected tanks. Washrooms, where people wash themselves, are not significant sources of nitrate. Faecal coliform
counts in groundwater from a random selection of wells are very high. The results have implications for the siting of wells
and toilets within villages in Indonesia.
Received, January 1999/Revised, August 1999/Accepted, August 1999 相似文献
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Tyas Mutiara Basuki Andrew K. Skidmore Patrick E. van Laake Iris van Duren Yousif A. Hussin 《国际地球制图》2013,28(4):329-345
A main limitation of pixel-based vegetation indices or reflectance values for estimating above-ground biomass is that they do not consider the mixed spectral components on the earth's surface covered by a pixel. In this research, we decomposed mixed reflectance in each pixel before developing models to achieve higher accuracy in above-ground biomass estimation. Spectral mixture analysis was applied to decompose the mixed spectral components of Landsat-7 ETM+ imagery into fractional images. Afterwards, regression models were developed by integrating training data and fraction images. The results showed that the spectral mixture analysis improved the accuracy of biomass estimation of Dipterocarp forests. When applied to the independent validation data set, the model based on the vegetation fraction reduced 5–16% the root mean square error compared to the models using a single band 4 or 5, multiple bands 4, 5, 7 and all non-thermal bands of Landsat ETM+. 相似文献
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Commercial digital photogrammetric software has been applied to convergent stereoscopic photography of human tooth replicas prepared to exhibit optical texture resulting in successful generation of 3D coordinate data. Tooth replicas were imaged using a semi-metric 35 mm camera and f = 100 mm macro lens on extension bellows. Model precision was within acceptable limits of 12 μ m or better for manual target matching and 21 μ m or better for automatic image matching. Further improvement in optical texture is required to achieve automatic image matching precision comparable to that of manual target matching. Small errors in interior orientation parameters attributed to instability in the bellows as well as small errors in the relative orientation resulted in some systematic errors. The use of a fixed camera lens system is expected to reduce these errors. When combined with commercially available, moderately priced, digital SLR cameras this brings 3D model generation closer to everyday clinical dental practice. 相似文献
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