Seepage analysis in a zoned anisotropic medium by the boundary element method

A simple and effective extension to the boundary element method for solving Laplace'S equation (?²u = 0) for boundary value problems is presented to solve steady confined and (or) steady unconfined seepage problems in zoned anisotropic mediums. Sample problems indicating the accuracy of results are given.     

Inflationary solution in higher dimensions

In this Letter the five-dimensional Kaluza-Klein cosmological model is studied in the presence of a massless scalar field, whose potential has a flat part. By use of the polynomial relation between the two scale factors, inflationary solutions are obtained. The results show that the scale factor corresponding to the extra dimension is either constant or varies inversely as some power of the usual scale factor.     

Stability analysis of a jointed beam

A numerical step-by-step procedure, analogous to the ‘Initial Stress Method,’ is presented for the analysis of a single-layer jointed rock beam subjected to gravity loads and in-plane in situ formation pressure. The joints are permitted to open at locations where the flexural stresses exceed flexural strength. The material properties may be different for each rock block and joint. A detailed algorithm is given for the solution of the problem. The results of several analyses indicating the relative effects of initial formation pressure, transverse load, stiffness of the joint material, and joint spacing on the response of a jointed beam are presented. The convergence characteristics of the numerical procedure are included. The joint material is assumed to be ‘no-tension’ type. Both the geometric and material non-linear effects are considered.     

Do Stable Isotope Data from Calcrete Record Late Pleistocene Monsoonal Climate Variation in the Thar Desert of India?

Late Pleistocene terrestrial climate records in India may be preserved in oxygen and carbon stable isotopes in pedogenic calcrete. Petrography shows that calcrete nodules in Quaternary sediments of the Thar Desert in Rajasthan are pedogenic, with little evidence for postpedogenic alteration. The calcrete occurs in four laterally persistent and one nonpersistent eolian units, separated by colluvial gravel. Thermoluminescence and infrared- and green-light-stimulated luminescence of host quartz and feldspar grains gave age brackets for persistent eolian units I–IV of ca. 70,000–60,000, ca. 60,000–55,000, ca. 55,000–43,000, and ca. 43,000–25,000 yr, respectively. The youngest eolian unit (V) is <10,000 yr old and contains no calcrete. Stable oxygen isotope compositions of calcretes in most of eolian unit I, in the upper part of eolian unit IV, and in the nonpersistent eolian unit, range between −4.6 and −2.1‰ PDB. These values, up to 4.4‰ greater than values from eolian units II and III, are interpreted as representing nonmonsoonal¹⁸O-enriched “normal continental” waters during climatic phases when the monsoon weakened or failed. Conversely, 25,000–60,000-yr-old calcretes (eolian units II and III) probably formed under monsoonal conditions. The two periods of weakened monsoon are consistent with other paleoclimatic data from India and may represent widespread aridity on the Indian subcontinent during isotope stages 2 and 4. The total variation in δ¹³C is 1.7‰ (0.0–1.7‰), and δ¹³C covaries positively and linearly with δ¹⁸O. δ¹³C values are highest when δ¹⁸O values indicate the most arid climatic conditions. This is best explained by expansion of C₄grasses at the expense of C₃plants at low latitudes during glacial periods when atmosphericpCO₂was lowered. C₄dominance was overridingly influenced by global change in atmosphericpCO₂despite the lowered summer rainfall.     

Regional investment effectiveness and development levels in China

For centuries, it has been taken for granted that social and economic development in China has an east-west spread, or from the coast to the interior. Even though a tremendous effort was made by the socialist government for thirty years (1949-1978) on rectifying this unhealthy imbalance, most people hold the belief that the spatial patterns of China's development remain the same as they were forty years ago. This deep-rooted concept plays an important role in shaping China's present economic development strategies. Thus, an evaluation of the impact of the goverment's regional balance effort remains critical. Understanding the changes and patterns of China's regional development is central to formulating appropriate policies for future planning. In this paper an overview of regional development is presented from the perspective of history. Regression between the total fixed capital investment and the combined industrial and agricultural output is analyzed, and an effort is made to find out the spatial distribution of regional investment effectiveness. A factor analysis based on twenty socio-economic variables revealed that apart from the traditional E-W regional disparity, the modern socialist dispersal policy has also affected the regional development in China. Though the historical economic factors unbalanced the development from E to W, the economic pratice advocated by Socialist China has reversed the tendency to some extent. A cluster analysis of 21 provinces, five autonomous administrative regions, and three municipalities identified new spatial patterns, and the result strengthened the finding that the effort of regional balance in the period of 1949–1978 is still at work.     

Estimation of Sugar Beet Aboveground Biomass by Band Depth Optimization of Hyperspectral Canopy Reflectance

Aboveground biomass of sugar beet influences tuber growth and sugar accumulation. Thus, accurate, rapid, and non-destructive technique of biomass estimation is important to optimize the crop management practices to attain the required aboveground biomass to support high tuber yields and optimal sugar content. The current research aimed to evaluate the performance of hyperspectral indices and band depth analysis, to remotely assess the aboveground biomass in sugar beet. The biomass and hyperspectral reflectance were collected at different growth stages in experimental and farmers’ fields. The model development was based on sugar beet plants sampled at various times during the growing period subject to seven nitrogen rates. The results showed that accuracy of biomass estimation was greater when using vegetation indices involving red edge bands (680–740 nm) as compared to that using the red light-based indices. Four types of optimized band depth information (band depth, band depth ratio, normalized band depth index, and band depth normalized to band area) involving the red edge further increased the accuracy of biomass estimation. This study demonstrated as the sugar beet biomass increased towards later growing period, biomass estimation using red light-based vegetation indices were less accurate as compared to that using band depth analysis in the vicinity of the red edge.     

Application of geogrids in waste dump stability: a numerical modeling approach

Geosynthetic is widely used to reinforce the weak rock mass, mine waste dump, soil slopes road cut slopes, etc. The present paper discusses the effect of geogrids on the stability of mine waste dump. The stability of mine waste dump has been done by Fast Langrage Analysis of Continua (FLAC) slope software, which is based on finite difference method. Reinforcement by geogrids mainly depends on the tensile strength, aperture size of geogrids, and particle size distribution of dump rock mass. Different permutations and combinations of spacing between two geogrid sheets have been taken into consideration to study the stability of mine waste dump. The factor of safety is calculated to quantify the effect of geogrids on waste dump slope. It has been observed from numerical modeling that the maximum slope angle is 45° at a height of 10 m. The scope of increasing slope angle from 45 to 60° is evaluated using geogrids. It has been found from the study that the factor of safety increases as the spacing between geogrids decreases. Maximum strain is also plotted of each case to identify the slip circle. The positions of geogrids modify the probable slip circle or failure plane of mine waste dump. Using ten geogrids at a spacing of 1 m, the slope angle can be increased up to 60° with factor of safety of 1.4.     

Toward physical aspects affecting a possible leakage of geologically stored CO2 into the shallow subsurface

In geological formations, migration of CO₂ plume is very complex and irregular. To make CO₂ capture and storage technology feasible, it is important to quantify CO₂ amount associated with possible leakage through natural occurring faults and fractures in geologic medium. Present work examines the fracture aperture effect on CO₂ migration due to free convection. Numerical results reveal that fracture with larger-aperture intensify CO₂ leakage. Mathematical formulation and equations of state for the mixture are implemented within the object-oriented finite element code OpenGeoSys developed by the authors. The volume translated Peng–Robinson equation of state is used for material properties of CO₂ and water.