scholarly journals EFFECT�OF�STRUCTURAL�ELEMENTS�ON�THE�KARST�WATER�RESOURCE�IN�THE�DEHDASHT�AREA

Author(s):  
Naser Ebadati
2017 ◽  
Vol 11 (1) ◽  
pp. 258-269 ◽  
Author(s):  
Xiaoqin Luo ◽  
Ganlu Wang ◽  
Yuliang Mou ◽  
Ruiying Liu ◽  
Hao Zhou ◽  
...  

Introduction: As an unconventional natural gas resource, shale gas is the current hot topic in the oil and gas industry. China is rich in shale gas resource, most of which lies in the Southwest Karst Area with its fragile ecological environment. Discussion: The following questions must be studied before exploration thereof: on one hand, shale gas mining requires a lot of water, on the other hand, if the karst region water resources can support shale gas mining over a large area, and if the consequent water/environmental pollution problems will bring more severe challenges to the sustainable development of society and the economy in the southwest karst area, there is a potential conflict requiring a research-based resolution. The water resource carrying capacity is an important measure of the potential sustainable development of a karst region, with its unique geological structure and fragile natural landscape. Therefore, the study of karst water resource carrying capacity is of great significance. Conclusion: This essay is based on Cenggong County, one of the five key shale gas exploration areas in Guizhou at the end of 2012. By calculating the water resource carrying capacity in the studied area with the help of the ecological footprint method, it is concluded that the existing water resources in the studied area can support shale gas exploration. However, shale gas mining will cause a change in the industrial structure within the region. In addition, it has significant effects on the bearing capacity of water resources in the ecological environment.


2021 ◽  
Author(s):  
Guillaume Cinkus ◽  
Naomi Mazzilli ◽  
Hervé Jourde

<p>10% of the world’s population is dependent on karst water resources for drinking water. Understanding the functioning of these complex and heterogeneous systems is therefore a major challenge for long term water resource management. Over the past century, different methods have been developed to analyse hydrological series, and subsequently characterize the functioning of karst systems. These methods can be considered as a preliminary step in the development and design of hydrological models of karst functioning for sustainable water resource management. Recent progress in analytical tools, as well as the emergence of data bases of discharge time series (e.g. the French SNO KARST database and the WoKaS database at global scale) allow reconsidering former typology of karst system hydrodynamic responses. Ten karst systems and associated spring discharge time series were considered for developing the typology. The systems are well-known with a high-quality monitoring and they cover a wide range of hydrological functioning, which ensure the relevance of the analyses. The methodology for the assessment and the development of the typology consisted in (i) the analysis of springs discharge time series according to four different methods, (ii) the selection or proposal of the most relevant indicators of karst systems hydrodynamics, and (iii) the interpretation of the information from these indicators based on principal component analysis and clustering techniques. A typology of karst systems accounting for 6 different classes is finally proposed, based on 3 aspects of functioning: the capacity of dynamic storage, the draining dynamic of the capacitive function and the variability of the hydrological functioning. The typology was applied to a wider dataset composed of spring discharge of 78 karst systems. The results show a relevant distribution of the systems among the different classes.</p>


Author(s):  
Jun Jiao

HREM studies of the carbonaceous material deposited on the cathode of a Huffman-Krätschmer arc reactor have shown a rich variety of multiple-walled nano-clusters of different shapes and forms. The preparation of the samples, as well as the variety of cluster shapes, including triangular, rhombohedral and pentagonal projections, are described elsewhere.The close registry imposed on the nanotubes, focuses attention on the cluster growth mechanism. The strict parallelism in the graphitic separation of the tube walls is maintained through changes of form and size, often leading to 180° turns, and accommodating neighboring clusters and defects. Iijima et. al. have proposed a growth scheme in terms of pentagonal and heptagonal defects and their combinations in a hexagonal graphitic matrix, the first bending the surface inward, and the second outward. We report here HREM observations that support Iijima’s suggestions, and add some new features that refine the interpretation of the growth mechanism. The structural elements of our observations are briefly summarized in the following four micrographs, taken in a Hitachi H-8100 TEM operating at an accelerating voltage of 200 kV and with a point-to-point resolution of 0.20 nm.


2003 ◽  
Vol 70 ◽  
pp. 201-212 ◽  
Author(s):  
Hideaki Nagase ◽  
Keith Brew

The tissue inhibitors of metalloproteinases (TIMPs) are endogenous inhibitors of the matrix metalloproteinases (MMPs), enzymes that play central roles in the degradation of extracellular matrix components. The balance between MMPs and TIMPs is important in the maintenance of tissues, and its disruption affects tissue homoeostasis. Four related TIMPs (TIMP-1 to TIMP-4) can each form a complex with MMPs in a 1:1 stoichiometry with high affinity, but their inhibitory activities towards different MMPs are not particularly selective. The three-dimensional structures of TIMP-MMP complexes reveal that TIMPs have an extended ridge structure that slots into the active site of MMPs. Mutation of three separate residues in the ridge, at positions 2, 4 and 68 in the amino acid sequence of the N-terminal inhibitory domain of TIMP-1 (N-TIMP-1), separately and in combination has produced N-TIMP-1 variants with higher binding affinity and specificity for individual MMPs. TIMP-3 is unique in that it inhibits not only MMPs, but also several ADAM (a disintegrin and metalloproteinase) and ADAMTS (ADAM with thrombospondin motifs) metalloproteinases. Inhibition of the latter groups of metalloproteinases, as exemplified with ADAMTS-4 (aggrecanase 1), requires additional structural elements in TIMP-3 that have not yet been identified. Knowledge of the structural basis of the inhibitory action of TIMPs will facilitate the design of selective TIMP variants for investigating the biological roles of specific MMPs and for developing therapeutic interventions for MMP-associated diseases.


2004 ◽  
Vol 171 (4S) ◽  
pp. 99-99
Author(s):  
Vincenzo Serretta ◽  
Vincenzo Altieri ◽  
Giuseppe Morgia ◽  
Rosalinda Allegro ◽  
Alessandra Di Lallo ◽  
...  

2011 ◽  
Author(s):  
Su Qingfu ◽  
Sha Shuang ◽  
Feng Di ◽  
Liu Lifeng

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