In this article, a method of high order, staggered grid, finite difference was used to model snapshots of seismic wave propagation and multi-azimuth surface seismic records in viscoelastic cracked monoclinic media. Th...In this article, a method of high order, staggered grid, finite difference was used to model snapshots of seismic wave propagation and multi-azimuth surface seismic records in viscoelastic cracked monoclinic media. The modeling results clearly show the anisotropy caused by the crack fill material and the viscoelastic wave field through the monoclinic media. Summarizing the regularity of seismic records for different azimuths, this study is a significant attempt to understand the wave fields propagated in real media and to propose a more rational theoretical model for the future.展开更多
Wetland environment of Assam is fast changing due to encroachments, dumping of solid and liquid wastes, excessive use of wetland water, over exploitation of wetland resources, overgrazing, over fishing, hunting, poach...Wetland environment of Assam is fast changing due to encroachments, dumping of solid and liquid wastes, excessive use of wetland water, over exploitation of wetland resources, overgrazing, over fishing, hunting, poaching, unscientific construction of engineering structures across and along the wetlands, unscientific land use in surrounding areas and various human interferences. On the other hand wetlands play an important role in charging ground water table, sinking of carbon, providing livelihood to thousands of people through fishing, collecting edible plants, agriculture, irrigation and commercial fisheries, besides enrich biodiversity and maintaining environmental quality of a region. The life of wetlands depends on the quantity and quality of water. Any change in water quality and quantity affect the biotic regime of the wetlands. Fish and other aquatic animals and plants found in all levels （floating, rooted, submergent and emergent etc.） are affected by the changes, which are taking place in wetland water. The present study concerns in understanding the environmental quality of the wetlands in Dimoria region of Kamrup （Metro） district, Assam based primarily on the water and soil quality of selected wetlands viz. Jiong, Parkhali, Bomani and Duani.展开更多
Isotopic tracers and water quality indicators （TDS （Total Dissolved Solid）, Cl^- and NO3^-contents） were used to characterize the recharge and control of the quality of groundwater in the alluvial aquifer beneath ...Isotopic tracers and water quality indicators （TDS （Total Dissolved Solid）, Cl^- and NO3^-contents） were used to characterize the recharge and control of the quality of groundwater in the alluvial aquifer beneath of the N＇djamena city. For this study, a total of 92 waters samples were taken and this included 67 wells, 21 pumps and 4 surface waters. Some groundwater has 6180 and 62H values close to those of the city of N＇djamena and/or the Chad river rains. However, all sampled points are below the Global Meteoric Water Line reflecting their evaporated characters. The interpretation of the isotopic tracers highlights that the recharge of the analyzed ground waters may result from two major mechanisms： （1） direct infiltration of local precipitation; （2） lateral inflow of river waters. The upper aquifer is the most vulnerable to pollution, especially during the recharge period. This pollution is due to the leaching of soils during the rainy season and the rise of the groundwater level which accompanies the overflowing of the Chad and causes the leaching of the polluted horizons of the unsaturated zone. In contrast, the lower aquifer has acceptable concentrations of solutes.展开更多
Risk quantification in grade is critical for mine design and planning.Grade uncertainty is assessed using multiple grade realizations,from geostatistical conditional simulations,which are effective to evaluate local o...Risk quantification in grade is critical for mine design and planning.Grade uncertainty is assessed using multiple grade realizations,from geostatistical conditional simulations,which are effective to evaluate local or global uncertainty by honouring spatial correlation structures.The sequential Gaussian conditional simulation was used to assess uncertainty of grade estimates and illustrate simulated models in Sivas gold deposit,Turkey.In situ variability and risk quantification of the gold grade were assessed by probabilistic approach based on the sequential Gaussian simulations to yield a series of conditional maps characterized by equally probable spatial distribution of the gold grade for the study area.The simulation results were validated by a number of tests such as descriptive statistics,histogram,variogram and contour map reproductions.The case study demonstrates the efficiency of the method in assessing risk associated with geological and engineering variable such as the gold grade variability and distribution.The simulated models can be incorporated into exploration,exploitation and scheduling of the gold deposit.展开更多
This paper deals with transformation procedures for observed GPS data from the world geodetic system WGS84 into the national geodetic grid datum SUTCN （system of united trigonometric cadaster network） and Baa（the B...This paper deals with transformation procedures for observed GPS data from the world geodetic system WGS84 into the national geodetic grid datum SUTCN （system of united trigonometric cadaster network） and Baa（the Baltic Sea after adjustment）.Transformation from WGS84 into SUTCN is performed most frequently by means of the 7element Helmert transformation with three identical points.Geodetic network was adjusted by two ways.展开更多
Fifteen turmeric genotypes from the germplasm held at National Root Crops Research Institute Umudike, Nigeria, were evaluated during the season of 2012-2013 at four locations-Jos （8.3833°N, 7.1833°E, 1,200 ...Fifteen turmeric genotypes from the germplasm held at National Root Crops Research Institute Umudike, Nigeria, were evaluated during the season of 2012-2013 at four locations-Jos （8.3833°N, 7.1833°E, 1,200 m a.s.l.）, Otobi （7.11667°N and 8.08333°E）, Umudike （5.4758°N, 7.5489°E） and Igbariam （6.4°N and 6.93333°E）-in order to select high yielding and stable turmeric cultivars with good quality for release in Nigeria. At each location, the experiment was laid out in randomized complete block design （RCBD） in three replications. Plot size was 9 m2. Data were collected on sprout count, plant height, number of tillers, number of leaves, main pseudo stem girth, rhizome number and weight. Analysis of variance was carried out on the combined data using GenStat Discovery Edition software. Results based on the combined data from four locations indicate that turmeric genotypes did not vary in percentage emergence and number of leaves. However, they varied in height, main pseudo stem girth, tillering, number and yield of fresh rhizomes. The effect of location on all attributes was significant （P 〈 0.05） with Jos location giving consistently the least values for all attributes thus suggesting that this location may not be suitable for the commercial production of turmeric. Genotype by environment interaction for most attributes was not significant indicating that the genotypes responded the same way across the locations. Ten genotypes, viz., UT39, UT44, UT46, UT58, UT50, UTI4, UT41, UT6, UT38 and UT35, are identified as promising and require further evaluation as pre-condition for nomination for official release to farmers.展开更多
Practically all physical, chemical, and biologi- cal processes can induce mass-dependent fractionation of mercury （Hg） isotopes. A few special processes such as photochemical reduction of Hg（Ⅱ） and photochemical ...Practically all physical, chemical, and biologi- cal processes can induce mass-dependent fractionation of mercury （Hg） isotopes. A few special processes such as photochemical reduction of Hg（Ⅱ） and photochemical degradation of methylmercury （MeHg） can produce mass- independent fractionation （MIF） of odd Hg isotopes （odd- MIF）, which had been largely reported in variable natural samples and laboratory experiments, and was thought to be caused by either nuclear volume effect or magnetic isotope effect. Recently, intriguing MIF of even Hg isotopes （even- MIF） had been determined in natural samples mainly related to the atmosphere. Though photo-oxidation in the tropopause （inter-layer between the stratosphere and the troposphere） and neutron capture in space were thought to be the possible processes causing even-MIF, the exact mechanism triggering significant even Hg isotope anomaly is still unclear. Even-MIF could provide useful information about the atmospheric chemistry and related climate changes, and the biogeochemical cycle of Hg.展开更多
文摘In this article, a method of high order, staggered grid, finite difference was used to model snapshots of seismic wave propagation and multi-azimuth surface seismic records in viscoelastic cracked monoclinic media. The modeling results clearly show the anisotropy caused by the crack fill material and the viscoelastic wave field through the monoclinic media. Summarizing the regularity of seismic records for different azimuths, this study is a significant attempt to understand the wave fields propagated in real media and to propose a more rational theoretical model for the future.
文摘Wetland environment of Assam is fast changing due to encroachments, dumping of solid and liquid wastes, excessive use of wetland water, over exploitation of wetland resources, overgrazing, over fishing, hunting, poaching, unscientific construction of engineering structures across and along the wetlands, unscientific land use in surrounding areas and various human interferences. On the other hand wetlands play an important role in charging ground water table, sinking of carbon, providing livelihood to thousands of people through fishing, collecting edible plants, agriculture, irrigation and commercial fisheries, besides enrich biodiversity and maintaining environmental quality of a region. The life of wetlands depends on the quantity and quality of water. Any change in water quality and quantity affect the biotic regime of the wetlands. Fish and other aquatic animals and plants found in all levels （floating, rooted, submergent and emergent etc.） are affected by the changes, which are taking place in wetland water. The present study concerns in understanding the environmental quality of the wetlands in Dimoria region of Kamrup （Metro） district, Assam based primarily on the water and soil quality of selected wetlands viz. Jiong, Parkhali, Bomani and Duani.
文摘Isotopic tracers and water quality indicators （TDS （Total Dissolved Solid）, Cl^- and NO3^-contents） were used to characterize the recharge and control of the quality of groundwater in the alluvial aquifer beneath of the N＇djamena city. For this study, a total of 92 waters samples were taken and this included 67 wells, 21 pumps and 4 surface waters. Some groundwater has 6180 and 62H values close to those of the city of N＇djamena and/or the Chad river rains. However, all sampled points are below the Global Meteoric Water Line reflecting their evaporated characters. The interpretation of the isotopic tracers highlights that the recharge of the analyzed ground waters may result from two major mechanisms： （1） direct infiltration of local precipitation; （2） lateral inflow of river waters. The upper aquifer is the most vulnerable to pollution, especially during the recharge period. This pollution is due to the leaching of soils during the rainy season and the rise of the groundwater level which accompanies the overflowing of the Chad and causes the leaching of the polluted horizons of the unsaturated zone. In contrast, the lower aquifer has acceptable concentrations of solutes.
文摘Risk quantification in grade is critical for mine design and planning.Grade uncertainty is assessed using multiple grade realizations,from geostatistical conditional simulations,which are effective to evaluate local or global uncertainty by honouring spatial correlation structures.The sequential Gaussian conditional simulation was used to assess uncertainty of grade estimates and illustrate simulated models in Sivas gold deposit,Turkey.In situ variability and risk quantification of the gold grade were assessed by probabilistic approach based on the sequential Gaussian simulations to yield a series of conditional maps characterized by equally probable spatial distribution of the gold grade for the study area.The simulation results were validated by a number of tests such as descriptive statistics,histogram,variogram and contour map reproductions.The case study demonstrates the efficiency of the method in assessing risk associated with geological and engineering variable such as the gold grade variability and distribution.The simulated models can be incorporated into exploration,exploitation and scheduling of the gold deposit.
文摘This paper deals with transformation procedures for observed GPS data from the world geodetic system WGS84 into the national geodetic grid datum SUTCN （system of united trigonometric cadaster network） and Baa（the Baltic Sea after adjustment）.Transformation from WGS84 into SUTCN is performed most frequently by means of the 7element Helmert transformation with three identical points.Geodetic network was adjusted by two ways.
文摘Fifteen turmeric genotypes from the germplasm held at National Root Crops Research Institute Umudike, Nigeria, were evaluated during the season of 2012-2013 at four locations-Jos （8.3833°N, 7.1833°E, 1,200 m a.s.l.）, Otobi （7.11667°N and 8.08333°E）, Umudike （5.4758°N, 7.5489°E） and Igbariam （6.4°N and 6.93333°E）-in order to select high yielding and stable turmeric cultivars with good quality for release in Nigeria. At each location, the experiment was laid out in randomized complete block design （RCBD） in three replications. Plot size was 9 m2. Data were collected on sprout count, plant height, number of tillers, number of leaves, main pseudo stem girth, rhizome number and weight. Analysis of variance was carried out on the combined data using GenStat Discovery Edition software. Results based on the combined data from four locations indicate that turmeric genotypes did not vary in percentage emergence and number of leaves. However, they varied in height, main pseudo stem girth, tillering, number and yield of fresh rhizomes. The effect of location on all attributes was significant （P 〈 0.05） with Jos location giving consistently the least values for all attributes thus suggesting that this location may not be suitable for the commercial production of turmeric. Genotype by environment interaction for most attributes was not significant indicating that the genotypes responded the same way across the locations. Ten genotypes, viz., UT39, UT44, UT46, UT58, UT50, UTI4, UT41, UT6, UT38 and UT35, are identified as promising and require further evaluation as pre-condition for nomination for official release to farmers.
基金supported by the Natural Science Foundation of China(41273023U1301231)+2 种基金the National Basic Research Program of China(2013CB430001)the Strategic Priority Research Program(XDB05030302)the‘‘Hundred Talent’’Project of Chinese Academy of Sciences and SKLEG
文摘Practically all physical, chemical, and biologi- cal processes can induce mass-dependent fractionation of mercury （Hg） isotopes. A few special processes such as photochemical reduction of Hg（Ⅱ） and photochemical degradation of methylmercury （MeHg） can produce mass- independent fractionation （MIF） of odd Hg isotopes （odd- MIF）, which had been largely reported in variable natural samples and laboratory experiments, and was thought to be caused by either nuclear volume effect or magnetic isotope effect. Recently, intriguing MIF of even Hg isotopes （even- MIF） had been determined in natural samples mainly related to the atmosphere. Though photo-oxidation in the tropopause （inter-layer between the stratosphere and the troposphere） and neutron capture in space were thought to be the possible processes causing even-MIF, the exact mechanism triggering significant even Hg isotope anomaly is still unclear. Even-MIF could provide useful information about the atmospheric chemistry and related climate changes, and the biogeochemical cycle of Hg.
