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Flaring of associated gas from oil exploitation has several consequences on the environment. This study explores the spatial
variability effects of gas flaring on the growth and development of cassava (Manihot esculenta), waterleaf (Talinum triangulare), and pepper (Piper spp.) crops commonly cultivated in the Niger Delta, Nigeria. Data was collected on soil and atmospheric temperature and moisture
at a 20-m interval, starting at 40 m from the flare point to a distance of 140 m. Lengths and widths of crop leaves, height
of crop plants and cassava yields were measured at the specified distances. The amino acid, ascorbic acid, starch, and sugar
constituents of the cassava yields were determined. The results suggest that a spatial gradient exists in the effects of gas
flares on crop development. Retardation in crop development manifests in decreased dimensions of leaf lengths and widths of
cassava and pepper crops closer to the gas flare point. Statistical analysis also confirms that cassava yields are higher
at locations further away from the flare point. In addition, the amount of starch and ascorbic acid in cassava decreased when
the plant is grown closer to the gas flare. High temperatures around the gas flare appear to be the most likely cause of this
retardation. The waterleaf crop, on the other hand, appears to thrive better around the gas flare point. 相似文献
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Resat Ulusay Ömer Aydan Melih Geniş Hisataka Tano 《Rock Mechanics and Rock Engineering》2013,46(6):1303-1321
The Cappadocia Region is one of the seven sites in Turkey included in the World Heritage List in 1985 by the United Nations Educational, Scientific and Cultural Organization (UNESCO) and includes structures carved into thick and soft tuffs that have survived and kept their integrity for a number of centuries. Besides existing ancient structures, new underground constructions have been undertaken. Considering the historical characteristics of the region, the construction of an underground structure was planned by the Municipality of Avanos Town to utilize a hill remnant from an abandoned quarry as an underground congress centre in the 1980s, but its construction has not yet been completed due to financial problems. In this study, integrated experimental, analytical and numerical analyses and an in situ monitoring program were undertaken to assess the stability conditions of the congress centre, which was carved into a soft tuff susceptible to long-term degradation processes. The experimental results indicate that the surrounding rock is quite vulnerable to cyclic freezing–thawing and wetting–drying processes. The strength of the rock is drastically reduced under saturated conditions, and the processes of freezing and thawing further accelerate the rock degradation under such conditions. Simple short-term stability analyses clearly show that some tensile cracking may take place and that the opening may suffer from some cracking problems 28–30 years after excavation. The analyses carried out for the long-term safety of the structure indicate that the most critical condition exists for the widest opening and that some supports at the middle of the widest opening may be necessary. Nevertheless, further studies on the long-term characteristics of this tuff are necessary to check this conclusion. The in situ monitoring clearly showed that some further crack propagation will occur, especially after rainy and freezing–thawing periods. 相似文献
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To model the cracking behaviour of brittle materials, different existing methods for treating the fracture zone can be used. The inner softening band (ISB) approach belongs to those methods which introduce a displacement discontinuity in which a constitutive relationship between opening displacements and tractions is assumed. This group of methods avoids difficulties in the localization zone caused by ambiguous definitions of strain measures and fracture zone widths. Whichever method is used, it is important that the proper amount of energy is dissipated. This is achieved automatically in ISB without the introduction of any extra material parameters other than the elastic constants and those describing the softening curve. Variations in mesh sizes and arrangements have shown no great influence on the total response, and the crack pattern is a part of the solution in contrast to most other methods in which it must be presumed. The concept is simple and inner softening bands have been successfully implemented within triangular three-node elements and preliminary within six-node triangular elements. The results obtained so far from various kinds of tests have shown very good performance and further development is planned. 相似文献
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Acoustic properties of deformed rocks in the Nobeoka thrust,in the Shimanto Belt,Kyushu, Southwest Japan 
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下载免费PDF全文 Yoshitaka Hashimoto Shogo Abe Hiroki Tano Gaku Kimura Asuka Yamaguchi Rina Fukuchi Jun Kameda Yohei Hamada Yujin Kitamura Koichiro Fujimoto Mio Eida 《Island Arc》2017,26(4)
Laboratory measurements for compressional and shear wave velocities (Vp and Vs, respectively) and porosity were conducted with core samples from the Nobeoka Thrust Drilling Project (NOBELL) under controlled effective pressure (5–65 MPa at 5 MPa intervals) and wet conditions. Samples were classified according to deformation texture as phyllite, foliated cataclasite, or non‐foliated cataclasite. Measured values of Vp, Vs, and porosity are within a range of 5.17–5.57 km/s, 2.60–2.71 km/s, and 2.75–3.10 %, respectively, for phyllite; 4.89–5.23 km/s, 2.46–2.57 km/s, and 3.58–4.53 %, respectively, for foliated cataclasite; and 4.90–5.32 km/s, 2.51–2.63 km/s, and 3.79–4.60 %, respectively, for non‐foliated cataclasite, which are all consistent with the previous laboratory experiments conducted with outcrop samples under dry conditions. However, our results also indicate higher Vp and Vs and lower porosity than those measured by the previous studies that adopted the wire‐line logging methods. The variations in Vp, Vs, and porosity are controlled by deformation structure and are greater for phyllite and foliated cataclasite than for non‐foliated cataclasite. 相似文献
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