Dump slope stability analysis – A case study

In opencast mining operation, the stability of waste materials stands at high priority from the safety and economic perspective. Poor management of overburden (OB) dump results the instability of slope in an opencast mine. The present paper deals with the stability analysis of dump material of an opencast coal mine at Talcher coal field, Angul district, Odisha, by means of different geotechnical parameters and mineralogical composition affecting the dump slope. The prolonged rainfall in the mining area causes dump failure and loss of valuable life and property. A recent dump failure that occurred in 2013 at Basundhara mines of Mahanadi Coalfields Limited (MCL), Odisha, took 14 lives, and created problems for the mining industry. Most of the dump failure that occurs in the study area are mainly due to increase in pore water pressure as a result of rainfall infiltration. The stability of the waste dump was investigated using the limit equilibrium analysis to suggest an economical, sustainable and safe disposal of the dump in the study area.     

The Impact of Hurricane Katrina on the Coastal Vegetation of the Weeks Bay Reserve,Alabama from NDVI Data

Normalized Difference Vegetation Index (NDVI) data were used to investigate vegetation changes after Hurricane Katrina (2005) for the Weeks Bay Reserve and surrounding area of coastal AL. Landsat 5 satellite images were acquired before landfall (March 24, 2005), after landfall (September 16, 2005), and 8 months after landfall (April 28, 2006). The March 2005 to September 2005 image comparison showed that average NDVI values decreased by 49% after landfall. Continuing into the next year, average NDVI values were −44% lower in April 2006 than they were in March 2005. Among habitat types, the estuarine emergent wetland experienced the largest average NDVI value decrease (−64%). The estuarine emergent wetland NDVI values continued to decrease by −27% from September 2005 to April 2006, whereas other habitats increased in NDVI. This continued suppression of NDVI values was attributed to increased salinity from the storm surge and to regional drought conditions that occurred after landfall. These results provide insight into the sensitivity of coastal vegetation from the interactions of both tropical cyclones and long-term environmental conditions.     

Experimental Study on Acoustoelastic Character of Rock Under Uniaxial Compression

This paper made a research about the change rule of elastic wave velocity with stress applied on rock from theoretical and experimental aspect. Firstly, a mathematical model of P-wave velocity and confining pressure of rock was set up from the point of acoustoelastic character. Effect of axial stress on P-wave velocity in granite and sandstone during uniaxial compression process was studied experimentally by using GAW-2000 rock mechanical testing system and RSM-SY5 ultrasonic wave testing system, and the relation curves of axial stress with P-wave velocity were obtained. Based on test data, acoustoelastic theoretical formulas of granite and sandstone were established and the best empirical formulas were fitted by using regression method. Meanwhile, a comparative analysis of the empirical and theoretical calculated values was carried out. Finally, the reliability of applying acoustoelastic theoretical formula in hard rock range was further verified based on the experimental data of granitic gneiss. The results show that the P-wave velocity experiences a rapid increase, gentle increase and then a sharp fall during the uniaxial compression process. The B-value in acoustoelastic theoretical formula (proportion coefficient determined by elastic modulus and third-order elastic constant) decreases exponentially with axial stress. The acoustoelastic theoretical formula can effectively reflect the relationship between rock acoustic velocity and stress within the allowable error, which can be the theoretical foundation of acoustoelastic geo-stress measurement of subsurface rock mass.     

Assessment of effectiveness of nature reserves on the Tibetan Plateau based on net primary production and the large sample comparison method

Twenty-one typical coupled large samples were chosen from areas within and surrounding nature reserves on the Tibetan Plateau using the large sample comparison method (LSCM). To evaluate the effectiveness of the nature reserves in protecting the ecological environment, the alpine grassland net primary production (NPP) of these coupled samples were compared and the differences between them before and after their establishment as protected areas were analyzed. The results showed that: (1) With respect to the alpine grassland NPP, the ecological and environmental conditions of most nature reserves were more fragile than those of the surrounding areas and also lower than the average values for the Tibetan Plateau. (2) Of the 11 typical nature reserves selected, the positive trend in the NPP for Manzetang was the most significant, whereas there was no obvious trend in Taxkorgan. With the exception of Selincuo, the annual NPP growth rate in the nature reserves covered by alpine meadow and wetland was higher than that in nature reserves consisting of alpine steppe and alpine desert. (3) There were notable findings in 21 typical coupled samples: (a) After the establishment of the nature reserves, the annual rate of increase in the NPP in 76% of samples inside nature reserves and 82% of samples inside national nature reserves was higher than that of the corresponding samples outside nature reserves. (b) The effectiveness of ecological protection of the Mid-Kunlun, Changshagongma, Zoige and Selincuo (Selin Co) nature reserves was significant; the effectiveness of protection was relatively significant in most parts of the Sanjiangyuan and Qiangtang nature reserves, whereas in south-east Manzetang and north Taxkorgan the protection effectiveness was not obvious. (c) The ecological protection effectiveness was significant in nature reserves consisting of alpine meadow, but was weak in nature reserves covered by alpine steppe. This study also shows that the advantage of large sample comparison method in evaluating regional ecology change. Careful design of the samples used, to ensure comparability between the samples, is crucial to the success of this LSCM.     

中国东北地区林地面积变化的动态模拟

There is plenty of forests in Northeast China which contributes a lot to the conservation of water and land resources, produces timber products, and provides habitats for a huge number of wild animals and plants. With changes of socio-economic factors as well as the geophysical conditions, there are dramatic changes on the spatial patterns of forest area. In this sense, it is of great significance to shed light on the dynamics of forest area changes to find the underlining reasons for shaping the changing patterns of forest area in Northeast China. To explore the dynamics of forest area change in Northeast China, an econometric model is developed which is composed of three equations identifying forestry production, conversion from open forest to closed forest and conversion from other land uses to closed forest so as to explore the impacts on the forest area changes from demographic, social, economic, location and geophysical factors. On this basis, we employ the Dynamics of Land System (DLS) model to simulate land-use conversions between forest area and non-forest cover and the land-use conversions within the sub-classes of forest area for the period 2000–2020 under business as usual scenario, environmental protection scenario and economic growth scenario. The simulation results show that forest area will expand continuously and there exist various kinds of changing patterns for the sub-classes of forest area, for example, closed forest will expand continuously and open forest and shrub will decrease a little bit, while area of other forest will keep intact. The research results provide meaningful decision-making information for conserving and exploiting the forest resources and making out the planning for forestry production in the Northeast China region.     

Heavy metals in sediments and their bioaccumulation in <Emphasis Type="Italic">Phragmites australis</Emphasis> in the Anzali wetland of Iran

Accumulation of metals in both sediments and Phragmites australis organs was studied. Samples were collected from seven stations located in Anzali wetland, Iran. The samples were analyzed by inductively coupled plasma mass spectrometry (ICP-MS). The results showed that concentration of the studied metals (except As and Cd) were higher in sediments than in P. australis organs. Metal accumulation was found to be significantly (P <0.05) higher in roots than in above-ground organs of P. australis. The bioaccumulation factor (BAF) and the transfer factor (TF) also verified the highest rate of metal accumulation in roots and their reduced mobility from roots to the above-ground organs. Pearson correlation coefficient showed significant relationships between metal concentrations in sediments and those in plant organs. It should be pointed out that sediment and plant samples exhibited higher metal concentrations in eastern and central parts than in western and southern parts of the wetland. The mean concentrations of all studied elements (except for Fe, V and Al) were higher in these sediment samples than in the Earth’s crust and shale. High accumulation of metals in P. australis organs (roots and shoots) is indicative of their high bioavailability in sediments of the wetland. The correlation between metal concentrations in sediments and in P. australis indicates that plant organs are good bioindicators of metal pollution in sediments of Anzali wetland.     

Livelihood changes and evolution of upland ethnic communities driven by tourism: a case study in Guizhou Province,southwest China

As an effective livelihood approach to alleviate poverty without rural population migration, ethnic tourism has become the primary choice of economic development in ethnic areas worldwide in addition to traditional livelihood approaches. This article applies the theories of livelihood to study the community evolution driven by tourism livelihood and examine three mountainous tourism communities in different stages of tourist area life cycle. Drawing on the methods of GIS spatial analysis, semi-structured interviews and questionnaires, this article proposes a sustainable livelihood framework for ethnic tourism to explore the evolution of ethnic tourism communities by identifying changes in livelihood assets (natural, financial, social, cultural and human capitals) in the process of tourism development. The results show that the development of ethnic tourism has led to changes in the increase of building land, and the diversification of land use functions with a trend of shifting from meeting local villagers' living needs to satisfying tourists, income composition and uneven distribution of tourism income spatially. Ethnic tourism also led to the deterioration of traditional social management structure, collapse of neighboring relationship, the over- commercialization and staged authenticity of ethnic culture, as well as the gradual vanish of agricultural knowledge with a trend of increasing modern business knowledge and higher education. In addition, these changes, involving livelihood assets from natural, economic, human, social and cultural aspects are interrelated and interactive, which form new evolution characters of ethnic community. This study reveals the conflicts over livelihood approaches which have formed new vulnerabilities to impact on sustainable evolution of ethnic communities. This research provides implications for achieving the sustainable development of ethnic communities with the driving force of tourism livelihood.     

Assimilation of ASAR data with a hydrologic and semi-empirical backscattering coupled model to estimate soil moisture

The most promising approach for studying soil moisture is the assimilation of observation data and computational modeling.However,there is much uncertainty in the assimilation process,which affects the assimilation results.This research developed a one-dimensional soil moisture assimilation scheme based on the Ensemble Kalman Filter(EnKF)and Genetic Algorithm(GA).A two-dimensional hydrologic model-Distributed Hydrology-Soil-Vegetation Model(DHSVM)was coupled with a semi-empirical backscattering model(Oh).The Advanced Synthetic Apertture Radar(ASAR)data were assimilated with this coupled model and the field observation data were used to validate this scheme in the soil moisture assimilation experiment.In order to improve the assimilation results,a cost function was set up based on the distance between the simulated backscattering coefficient from the coupled model and the observed backscattering coefficient from ASAR.The EnKF and GA were used to re-initialize and re-parameterize the simulation process,respectively.The assimilation results were compared with the free-run simulations from hydrologic model and the field observation data.The results obtained indicate that this assimilation scheme is practical and it can improve the accuracy of soil moisture estimation significantly.     

Minority women’s microenterprises in rural areas of the United States of America: African American,Hispanic American and Native American case studies

Women in many rural areas of the US often engage in small-scale businesses as one of several avenues for contributing to household incomes. In those geographical areas that contain a significant minority population, many of the women's businesses display the cultural diversity of the regions in which they live. Likewise, women's roles as economic providers as well as wives and mothers are reflected in the manner in which they operate their businesses. Candida Brush suggests that women's strategies for operating their businesses are highly integrative because women's business decisions are intertwined with familial responsibilities, household economic demands and desires to contribute to their communities. Hispanic and Native American women in the Four Corners region of southwestern US and African American women in central Virginia participated in interviews in which they responded to numerous short answer and open-ended questions about their businesses and decision-making strategies. From these interviews an image emerges of rural minority business women who are operating their businesses at the nexus of family obligations, economic necessities, cultural ties and with a commitment for serving their communities. This revised version was published online in July 2006 with corrections to the Cover Date.     

Experiment study on RC frame retrofitted by the external structure

A new retrofitting method is proposed herein for reinforced concrete (RC) structures through attachment of an external structure. The external structure consists of a fiber concrete encased steel frame, connection slab and transverse beams. The external structure is connected to the existing structure through a connection slab and transverse beams. Pseudostatic experiments were carried out on one unretrofitted specimen and three retrofitted frame specimens. The characteristics, including failure mode, crack pattern, hysteresis loops behavior, relationship of strain and displacement of the concrete slab, are demonstrated. The results show that the load carrying capacity is obviously increased, and the extension length of the slab and the number of columns within the external frame are important influence factors on the working performance of the existing structure. In addition, the displacement difference between the existing structure and the outer structure was caused mainly by three factors: shear deformation of the slab, extraction of transverse beams, and drift of the conjunction part between the slab and the existing frame. Furthermore, the total deformation determined by the first two factors accounted for approximately 80% of the damage, therefore these factors should be carefully considered in engineering practice to enhance the effects of this new retrofitting method.