Showing papers in "Geosystem Engineering in 2012"
TL;DR: In this paper, coal combustion by-products (CCPs) are defined and compared to other materials, such as sand, concrete, and sand filling, and coal slag is used as a glassy grit material for sand blasting.
Abstract: With the continued use of coal to generate electricity for the world's power needs, coal combustion by-products (CCPs) will be produced in greater quantities during the ensuing decades. About 130 million tons of CCPs are produced annually from the 600 coal-fired power plants currently operating in the USA, with estimates of 500 million tons produced worldwide. Five major types of CCPs exist: bottom ash; boiler slag; fly ash; fluidized bed ash; flue gas desulfurization ash. Bottom ash does not generally constitute a disposal problem because it is extensively used as aggregate fill material for construction projects, filler in construction materials (wall board and dry wall) and de-icing solids for roads. Boiler slag is used for similar purposes as bottom ash, but it can be used as a glassy grit material for sand blasting. Fly ashes constitute 70% of the by-products generated and these ashes are produced in several ways in a power plant depending on the boiler type and the emission control system employed a...
54 citations
TL;DR: In this paper, the feasibility of utilizing oil extracted from plant seed in the contaminated areas, the phytoremediation applicability of soils contaminated with heavy metals and its follow-up result in the production of biodiesel was investigated.
Abstract: In order to examine the feasibility of utilizing oil extracted from plant seed in the contaminated areas, the phytoremediation applicability of soils contaminated with heavy metals and its follow-up result in the production of biodiesel was investigated. Brassica napus was chosen as the main target plant because it is widely used for phytoremediation and is an advantage of biodiesel production. From the perspective of heavy metal concentrations in Brassica napus, plants grown in contaminated soil show significantly higher concentration than those in non-contaminated soil. From the results of sequential extraction analysis, it was also found that heavy metal concentrations in plant may be increased with the enhancement of phyto-available fraction of heavy metal in the soil. These results show the feasibility of oil production extracted from Brassica napus, which was grown in heavy metal-contaminated soil. The seed contains a low concentration of most kinds of heavy metals except Zn in soil, which is essent...
47 citations
TL;DR: In this paper, pressure leaching, electrogenerated chlorine leaching and concentrated sulfuric acid leaching were performed to investigate the leaching behavior of monazite concentrate with various temperature ranges.
Abstract: Pressure leaching, electrogenerated chlorine leaching and concentrated sulfuric acid leaching were performed to investigate the leaching behavior of monazite concentrate with various temperature ranges The pressure leaching was tested at 5 atm and 220°C and the concentrations of Ce and La increase with increasing sulfuric acid concentration from 001 mol/L to 1 mol/L and decreasing the particle size of monazite concentrate from − 200 mesh − +325 mesh to − 325 mesh In the electrogenerated chlorine leaching system, the concentration of La decreases with increasing temperature from 30°C to 70°C, which resulted from a decrease in solubility of chlorine with increasing temperature In the concentrated sulfuric acid leaching system, the leaching ratios of La and Nd increase to over 99% with increasing temperature to 220°C The higher metal concentration of Ce, La and Nd are obtained in the concentrated sulfuric acid leaching system than in the pressure leaching and the electrogenerated chlorine leaching syste
17 citations
TL;DR: In this paper, the authors introduce characteristics of coal mine drainage in Vietnam, the specific difficulties of coalmine drainage management and treatment, solutions that have been applied and their results, and the necessity of technology and management experiences that are needed in order to manage the resources of coal mines effectively and to contr...
Abstract: At present, Vietnam National Coal and Mineral Industries Holding Corporation Limited (VINACOMIN) controls 35 coal mines, including 10 underground mines and 25 open pits in Quang Ninh coal basin. The coal mining area in Quang Ninh has a very special characteristic that its coal seams are located near the coast of Ha Long Bay and many coal mines are situated close to the coast. Previously, mine water from the mines was not treated and discharged directly into the sea. Since 2009, VINACOMIN has constructed 29 mine water treatment stations. The management of mine water in coal mines in Quang Ninh coal basin is quite difficult due to tropical rains.This article introduces characteristics of coal mine drainage in Vietnam, the specific difficulties of coal mine drainage management and treatment, solutions that have been applied and their results. Also discussed is the necessity of technology and management experiences that are needed in order to manage the resources of coal mine drainage effectively and to contr...
14 citations
TL;DR: In this paper, a prospective process for treating a large volume of the waste, slag atomizing technology is developed, and the slag was atomized under air gas surrounding with the velocity of 75 m/second.
Abstract: Gold mine tailing, red mud and waste limestone cause very serious problems to the environment. Due to their abundant amount of waste as well as difficulties with disposal, an appropriate recycling technology of this waste is necessary to mine and smelting industries. As a prospective process for treating a large volume of the waste, slag atomizing technology is developed. Slag composition is the most important factor in manufacturing slag granules. The waste was mixed with the ratio of 26 wt% of tailing, 38 wt% of red mud and 36 wt% of waste limestone for a better melting operation regarding product property, viscosity and melting temperature. After pelletizing the above mixture, the pellets were dried in an oven for 2 days and were melted in an electric arc furnace at 1500(C for 2 hours. Separated slag was atomized under air gas surrounding with the velocity of 75 m/second. The final obtained precious slag balls might have good physical properties, such as highly spherical shape and narrow size distribut...
10 citations
TL;DR: In this paper, a new approach using decomposed time series of energy consumption is applied to investigate a decoupling issue on economic growth and energy consumption, which can help explain the coupling-decoupling controversies on energy and economic growth.
Abstract: To investigate a decoupling issue on economic growth and energy consumption, a new approach using decomposed time series of energy consumption is applied in this study. To capture the actual growth effect on energy consumption, an index decomposition analysis is performed first. From the decomposition results, the decomposed energy consumption data could be obtained. With those data, a causality analysis to figure out the relationship between economic growth and actual energy consumption is conducted. The results show that a bidirectional causal relationship was observed in the US, which could not be derived from the conventional approach. In other words, a hidden causal relationship between economic growth and actual energy consumption was revealed through the approach proposed in this paper. These efforts can help explain the coupling–decoupling controversies on energy and economic growth.
9 citations
TL;DR: In this article, a sensitive, rapid and reproducible analytical method for quantifying triclocarban (TCC) and triclosan (TCS) in biosolid and soil samples using pressurized liquid extraction (PLE) and ultraperformance liquid chromatography with triple quadrupole mass spectrometry (UPLC-MS-MS) is developed and presented.
Abstract: A sensitive, rapid and reproducible analytical method for quantifying triclocarban (TCC) and triclosan (TCS) in biosolid and soil samples using pressurized liquid extraction (PLE) and ultraperformance liquid chromatography with triple quadrupole mass spectrometry (UPLC-MS-MS) is developed and presented in this study. The analytes were ionized in a new combined ESI-APCI (ESCi) operating with negative ion mode. Recoveries of TCC and TCS from biosolids and soil samples ranged from 93% to 102%, and the method detection limits were both 0.05 ng/g (d.w.). The intra- and inter-day precision of the assay fell within acceptable ranges of 15%. The developed method was applied to evaluate the occurrence of these compounds at two wastewater treatment plants and five farms in Michigan. TCC and TCS analyzed were detected in three biosolids samples at high concentrations. TCC and TCS were found at a low or trace level of concentration in the five soil samples which had had biosolids applied to them. This indicates that ...
7 citations
TL;DR: In this paper, the Ho-nam coal mine passive treatment system, which consists of an oxidation pond, successive alkalinity producing system (SAPS) and aerobic wetland, was investigated to estimate the treatment efficiency of the entire system and each treatment step.
Abstract: The Ho-nam coal mine passive treatment system, which consists of an oxidation pond, successive alkalinity producing system (SAPS) and aerobic wetland, was investigated to estimate the treatment efficiency of the entire system and each treatment step. After the acid mine drainage of Ho-nam coal mine moves through the entire system, metal concentration and acidity decreases and alkalinity increases. Acid mine drainage has been treated successfully by the Ho-nam coal mine passive treatment system. However, iron ions were not removed sufficiently in the oxidation pond even though ferrous ions oxidized to ferric ions. Furthermore, in SAPS, Fe concentration decreased rapidly but sulfate reducing bacteria activity was not shown in the system. These results suggest that the objectives of each step were not achieved as designed, although the system was found to be successful.
7 citations
TL;DR: The mangrove oyster Crassostrea rhizophorae was harvested from clutches associated with mangroves in the Qua Iboe Estuary and adjoining creeks to determine the concentrations of total petroleum hydrocarbons (TPH) and trace metals (Fe, Ni, Pb, Cr, V, Cu and Zn) and to understand their bioaccumulation status as mentioned in this paper.
Abstract: The mangrove oyster Crassostrea rhizophorae was harvested from clutches associated with mangroves in the Qua Iboe Estuary and adjoining creeks to determine the concentrations of total petroleum hydrocarbons (TPH) and trace metals (Fe, Ni, Pb, Cr, V, Cu and Zn) and to understand their bioaccumulation status. The mean concentrations of trace metals in C. rhizophorae were 36.06 mg·kg− 1 for Fe, 0.58 mg·kg− 1 for Ni, 0.05 mg·kg− 1 for Pb, 0.66 mg·kg− 1 for Cr, 0.32 mg·kg− 1 for V, 6.70 mg·kg− 1 for Cu and 3.93 mg·kg− 1 for Zn. The oysters demonstrated relative affinity for accumulation of Fe, Cu and Zn and the relative status of the metals accumulated, in comparison with the background trace metal load, revealed bio-concentration factors of 0.024, 0.016, 0.004, 0.213, 0.037, 0.302 and 0.036 for Fe, Ni, Pb, Cr, V, Cu and Zn, respectively. The concentrations of TPH in the oyster were highly variable and ranged between 6.37 and 8.44 mg·kg− 1 dry weight of C. rhizophorae. Although the correlation between TPH leve...
7 citations
TL;DR: In this paper, the authors describe a pillar design methodology that was developed from a study of pillar performance in operating stone mines and a numerical model (FLAC3D) for the entire rock mass has been developed in order to analyze the stability of the entire underground opening.
Abstract: This paper describes a pillar design methodology that was developed from a study of pillar performance in operating stone mines. A number of methodologies have been developed to calculate full-scale mine pillar strengths based on laboratory scale strength obtained from specimens. Data were collected on rock mass quality, pillar conditions, mining dimensions and intact rock strength. Results showed that current mining practices have resulted in generally stable pillar layouts, without recent cases of extensive pillar collapses; however, failure of the pillars was found to be related to spalling of hard brittle rock, shearing along pre-existing angular discontinuities or progressive extrusion of soft infill material on bedding planes. A numerical model (FLAC3D) for the entire rock mass has been developed in order to analyze the stability of the entire underground opening. A preliminary monitoring phase has been realized, aimed at controlling abandoned rock structure movement at the most significant disconti...
6 citations
TL;DR: A zero-valent iron (ZVI) treatment system combined with pH adjustment, aeration, sedimentation and microfiltration processes was developed for the robust removal of nitrate from groundwater as discussed by the authors.
Abstract: A zero-valent iron (ZVI) treatment system combined with pH adjustment, aeration, sedimentation and microfiltration processes was developed for the robust removal of nitrate from groundwater. Powdered ZVI dosed at 10 g L− 1 removed nitrate by 166 mg L− 1, of which 80% were converted to ammonium ion for a given contact time of 125 h. By diffusing gaseous carbon dioxide (CO2) into the ZVI reactor, pH was desirably controlled in the range of 5.5–6.5, and concurrently < 0.5 mg L− 1 dissolved oxygen was consistently maintained during the longer-term of dissolved oxygen ZVI treatment system. The combination of ZVI treatment and CO2 gas bubbling reached up to 35% removal of nitrate and passivation on the surface of ZVI was prevented by diffusing CO2 gas. Soluble Fe (II) concentration of mixed liquor in the ZVI reactor ranged between 0.2 and 7.8 mg L− 1 and Fe (II) dissolved in the ZVI-treated water was almost completely removed by subsequent aeration. The overall result shows that the novel ZVI treatment system i...
TL;DR: Twenty days after the indigenous acidophilic bacteria were inoculated to a pyrite-leaching medium, the bacterial sample had a greater concentration of Fe and Zn than within the control sample.
Abstract: Indigenous acidophilic bacteria living in a hot acidic spring near Hatchobaru thermal electricity plant in Japan were incubated and used for the bioleaching experiment. The indigenous acidophilic bacteria grew properly in the leaching (sulfur-rich) solution and, over the course of incubation, the pH decreased and Eh increased. In relation to the bacterial growth-curve, the lag phase was hardly shown while the exponential phase was significantly fast. Following Gram staining of the bacteria, they were categorized into Gram-negative and Gram-positive. When the bacteria were inoculated to pyrite, rod-shaped bacteria and round-shaped microbes were well attached to the surface of the pyrite. The size of the rod-shaped bacteria ranged from 1.05–1.10 μm to 4.01–5.38 μm. Round-shaped microbes were more than 3.0 μm in diameter. Paired cells of rod-shaped bacteria were linearly attached to the surface of the pyrite. The round-shaped microbes showed strong organic attachment. Twenty days after the indigenous acidoph...
TL;DR: In this paper, the chemistry of acid mine drainage treatment, the mechanisms and the rates of oxidation of Fe(II) to produce Fe(III) oxides and strategies that can be used to manipulate the treatment chemistry in order to control the rate of oxidation and the quality of the residual Fe(3)-oxides.
Abstract: Fe(II) and acidity are the most commonly encountered contaminants in acid mine drainage (AMD). Passive treatment for AMD involves addition of alkalinity, aerobic processes that result in oxidation of Fe(II) to Fe(III) oxides, and anoxic treatments in which sulfate is reduced to sulfide with consequent precipitation of Fe(II) sulfides. Alkalinity is usually provided by dissolution of limestone in passive treatments or by addition of lime or caustic in active systems. This paper focuses on the chemistry of AMD treatment, the mechanisms and the rates of oxidation of Fe(II) to produce Fe(III) oxides and strategies that can be used to manipulate the treatment chemistry in order to control the rate of oxidation and the quality of the residual Fe(III) oxides.
TL;DR: In this paper, a method to manufacture cementitious materials with municipal solid waste incineration fly ash (MF) and water sludge (WS) sintered at temperatures ranging from 1000°C to 1300°C was proposed.
Abstract: This study proposes a method to manufacture cementitious materials with municipal solid waste incineration fly ash (MF) and water sludge (WS) sintered at temperatures ranging from 1000°C to 1300°C. The utilized wastes contain a variety of cement components, such as Ca, Al, Cl, Si and SO3. The mixing ratio of MF to WS was determined according to the stoichiometry molar ratio of Ca/Al of calcium chloroaluminate, Ca12Al14O32Cl2. When the mixture was sintered at sintering temperature between 1000oC and 1100oC, calcium chloroaluminate (Ca12Al14Cl2O32) and melilite (Ca4Al2MgSi3O14) were formed as cementitious materials, and calcium sulfoaluminate (Ca4Al6SO14) was formed accompanying the consumption of calcium chloroaluminate starting at a sintering temperature of 1200oC. In the hydration reaction, calcium chloroaluminate, melilite and calcium sulfoaluminate synthesized through the sintering process formed Ca4Al2Cl2O6·10(H2O), Ca5Al2(OH)4Si3O12 and ettringite (Ca6Al2(SO4)3(OH)12·26H2O), respectively, as hydrates...
TL;DR: In this paper, a seismic object detection method using supervised neural networks to combine seismic attributes and transform them into a single "object probability" attribute is described. But, the limitation that this approach has over other approaches is that it does not incorporate machine intelligence to validate attribute selection.
Abstract: This paper describes a seismic object detection method using supervised neural networks to combine seismic attributes and transform them into a single ‘object probability’ attribute. Unlike other widely used methods, the approach incorporates interpreter's knowledge into the well-known process of combination of multiple attributes. In fact, the interpreter decides the anomaly to be addressed and picks examples of anomalies for the neural networks. The approach completely relies on the interpreter to select the input attributes. However, the limitation that this approach has over other approaches is that it does not incorporate machine intelligence to validate attribute selection. Thus, the present study attempts to overcome this limitation and uses neural networks in the process. The integration of a neural network has played a key role in determining the type and number of attributes used in the prediction and, thus, gives the approach more reliability and confidence. Furthermore, with the help of the ne...
TL;DR: In this paper, a process to produce pure calcite-type calcium carbonate by the carbonation of air-cooled blast furnace slag, which is a waste material and which has been utilized in limited applications, is reported.
Abstract: A process to produce pure calcite-type calcium carbonate by the carbonation of air-cooled blast furnace slag (BFS), which is a waste material and which has been utilized in limited applications, is reported here. The process is composed of two reactions. First, calcium ions are extracted from an air-cooled BFS slurry under pressurized gaseous CO2 (1 to 5 MPa) at 273 K, at which the extracted calcium ions and calcium carbonate formed during the extraction process are dissolved in the solution due to the high solubility of the calcium carbonate under the high pressure of CO2. The second reaction is the precipitation of pure calcite-type calcium carbonate at atmospheric pressure at the same temperature after the removal of the solid residue remaining after the extraction process. Gaseous CO2 was fed at atmospheric pressure to increase the precipitation ratio of calcium carbonate by the carbonation of the unreacted calcium ions in the solution. In this study, the influences of the following parameters on the ...
TL;DR: In this article, the authors focused on the successful growth of the indigenous acidophilic bacteria living in Japanese acid hot springs in a growth medium containing elemental sulfur under moderate thermopile conditions.
Abstract: This study focused on the successful growth of the indigenous acidophilic bacteria living in Japanese acid hot springs in a growth medium containing elemental sulfur under moderate thermopile conditions. As the bacteria grew in the growth medium, its pH decreased and Eh increased. While the rod-shaped bacteria of about 1 μm grew into many populations at the medium length of 5 μm, a strain of above 9.8 μm grew only in a small minority. When the bacteria were stained with Gram, some bacteria 1 μm in length were proved Gram negative, and larger bacteria which were 5-6 times longer than those of 1 μm were proved Gram positive. The colonies of rod-shaped bacteria 1 μm in morphology and 1 μm in length were attached to the chalcopyrite surface and those with filament morphology ranging from 6 μm to 8.5 μm in length were attached singularly. When the indigenous acidophilic bacteria were inoculated on a chalcopyrite surface, the ion concentrations in Cu, Fe and Zn leached were two, four and six times higher than t...
TL;DR: In this paper, the authors used calcite twins in limestone distributed in South Korea to examine paleostress and tectonic implications, and calculated the maximum shortening axes from calcite twin.
Abstract: In order to examine paleostress and tectonic implications, calcite twins in limestone distributed in South Korea were used. The average twin thickness and intensity increase with increasing the total twin strain. Calcite twins in the study area as an indicator of deformation temperature might be produced at temperatures lower than 200°C approximately, being considered for the total twin strain, the average twin thickness and intensity and morphology of calcite. The maximum shortening axes calculated from calcite twins show the NE-SW or NEE-SWW, NW-SE or NWW-SEE and N-S or NNW-SSE directions. These maximum shortening directions are consistent with many fault directions developing in the study area, in particular with the NE-SW main tectonic direction in the Korean Peninsula. Paleostress results from present and other previous studies suggest that the NE-SW maximum shortening direction during the Late Permian to Early Triassic Songrim orogeny in the Korean Peninsula can be compatible with the Indosinian oro...
TL;DR: In this article, a two-step simulation with a full model and a submodel using FLAC3D was used to combine the influence of in situ stress, tunnel excavation, deposition hole drilling, confining pressure, and thermal loading all together.
Abstract: Korea participated in DECOVALEX-2011, which is an international cooperation project for enhancing the reliability of computer simulations under the conditions of radioactive waste repositories, and modeled the laboratory compression tests and the in situ Aspo pillar stability experiment (APSE). From the comparison of the results with foreign research teams, it was possible to enhance the reliability of the computer simulation of the complex thermo-mechanical (TM) coupling behavior of rock mass. It was found that the two-step simulation with a full model and a submodel using FLAC3D was effective to combine the influence of in situ stress, tunnel excavation, deposition hole drilling, confining pressure, and thermal loading all together. One of the important results was the estimation of spalling strength of Aspo granite as 120 MPa after comparing the notch depth, notch length, and breakout angle of the notch with actual observation.
TL;DR: In this paper, the authors estimate the vertical sweep efficiency of injected CO2 in an enhanced coal bed at the field scale by considering the aquifer position and strength, and they show that the viscosity flow effectively improves CO2 movement due to high permeability in the bottom layer.
Abstract: To estimate methane recovery from an enhanced coal bed at the field scale, it is important to understand CO2 movement. Since coal beds are generally connected with aquifers, CO2 movement is affected by aquifer position and strength. Under conditions of no aquifer, CO2 initially has a tendency to move to the top layer of the coal seam due to the buoyancy effect. However, the permeability of the upper layer is decreased due to the swelling effect. The viscosity flow effectively improves CO2 movement due to high permeability in the bottom layer. Because of the offsetting effects of viscosity and gravitational flow, the vertical sweep efficiency of injected CO2 is very effective. Thus, methane recovery is highly calculated. Under conditions of an upper aquifer, CO2 flow in the bottom layer decreased as the injected CO2 leaked to the aquifer. As the hydraulic connection between the overlying aquifer and the coal seam is strong, the vertical sweep efficiency is weakened due to the high gas leakage rate. Therefo...
TL;DR: In this article, the applicability of reductive immobilization of As(V) by Fe(0) [zero valent iron (ZVI)] to the contaminated soil was determined.
Abstract: The objective of this study was to determine the applicability of reductive immobilization of As(V) by Fe(0) [zero valent iron (ZVI)] to the As contaminated soil. The experiments comprised reactions between ZVI and As(V) absorbed onto goethite-coated sand (GCS) simulating heterogeneous soil environment, and reactions between ZVI and dissolved As(V) simulating homogeneous environment. Arsenic(III+V) removal ratio in the heterogeneous system was lower than in the homogeneous system, which was due to the incomplete reduction of As(V) adsorbed onto GCS. Incomplete reduction might be caused by difficulty of desorption of As(V) or lower accessibility of ZVI to As(V) adsorbed onto GCS to react. Almost half of As(V) adsorbed onto GCS was instantly desorbed. Arsenic(III) produced by reaction between As(V) and ZVI was quickly removed by iron hydroxide including As(III). Effect of air injection for As removal in the heterogeneous system was smaller than in the homogeneous system because of difficulty in the oxidatio...
TL;DR: The role of pH on metal ion adsorption by unmodified coir dust and its modified extract forms (namely carboxylated and sulphonated coir extract resins) was studied in a batch system as mentioned in this paper.
Abstract: The role of pH on metal ion adsorption by unmodified coir dust and its modified extract forms (namely carboxylated and sulphonated coir extract resins) was studied in a batch system. The zero point charge pH (pH pzc) of the adsorbents was determined and the results demonstrated that the amount of metal ions adsorbed by the adsorbents was dependent on pH(pzc). The adsorption of these metal ions by the adsorbent increased with increasing pH. The unmodified coir dust, being a lignocellulosic material, removed more metal ions than the modified coir extract resins derived from a tannin-polyhydroxy compound. Hydroxyl, carboxylic and sulphonic functional groups are responsible for the metal ion binding in these adsorbents, as revealed by infra-red spectroscopic analysis. Coir dust, carboxylated coir extract (CTR) and sulphonated coir extract resin (STR) are effective adsorbents for removal of metal ions from aqueous solution and industrial effluents/wastewater.
TL;DR: In this paper, a steam assisted gravity drainage (SAGD) process simulations described in this paper have been optimized to have the lowest cumulative steam:oil ratio (CSOR), highest recovery factor (RF) and highest calendar day oil rate (CDOR) in order to obtain optimal operation conditions.
Abstract: The steam-assisted gravity drainage (SAGD) process simulations described in this study have been optimized to have the lowest cumulative steam:oil ratio (CSOR), highest recovery factor (RF) and highest calendar day oil rate (CDOR) in order to obtain optimal operation conditions. In addition, net present value (NPV) calculations were performed for each simulation case to take the time factor into account. A simple thermal efficiency parameter (STEP), based on CSOR, CDOR and RF for the time corresponding to SOR = 4, was developed to evaluate the performance of a SAGD project under optimized conditions. A linear relationship was found to exist between STEP and NPV, with a correlation coefficient in excess of 0.96 for most of the cases studied. For each simulation case, highest values of NPV and STEP indicated optimum SAGD operating conditions.
TL;DR: The results indicated that the oxidation of As(III) by indigenous chemoautotrophic bacteria may influence the speciation of As in natural geological settings and showed the potential for application to the effective As remedial processes in As-contaminated aquifer and subsurface.
Abstract: In order to understand geomicrobial processes that mediate the mobility of As in natural settings, indigenous bacteria were isolated from As-laden geological materials under 10 mM As(III) condition without supply of carbon source. These geological materials were soil from the black shale in Dukpyung area and sediment in the Dukeum mine area. The isolated bacteria were inoculated to 5 mM As(III) solution, and variations in As species were monitored over time. The rate of microbial As(III) oxidation by the isolate from Dukpyung black shale soil was significantly slow, providing no clear distinction from chemical As(III) oxidation. In contrast, the rate of As(III) oxidation by the bacterium isolated from Dukeum mine sediment showed a remarkable increase when compared with chemical reaction. The results indicated that the oxidation of As(III) by indigenous chemoautotrophic bacteria may influence the speciation of As in natural geological settings and showed the potential for application to the effective As re...
TL;DR: In this article, the authors show that there are at least two solutions for waveform inversions in the Laplace domain: the true velocity model; the long-wavelength background velocity model.
Abstract: The non-uniqueness of the solution is one of the major obstacles for a successful full waveform inversion. This paper shows that there are at least two solutions for waveform inversions in the Laplace domain: the true velocity model; the long-wavelength background velocity model. The Laplace domain inversion can recover the true velocity model if provided with an accurate initial model, but it will instead result in a smooth long-wavelength velocity model if the initial model is inaccurate and smooth. In this case, the inverted long-wavelength velocity model can still be used for either migration or as an initial velocity model for frequency domain waveform inversion.
TL;DR: In this article, the 3D modeling results of seismic refraction surveys performed to calculate the earth volume of cut-slope were presented, which showed an accurate outline of the actual slope and p-wave velocity distribution.
Abstract: This paper presents 3-D modeling results of seismic refraction surveys performed to calculate the earth-volume of cut-slope. 3-D modeling was conducted for four p-wave profiles of seismic refraction data and analysis of physical properties (uniaxial compressive strength, rock core p-wave velocity) of the sampled rock cores was carried out to estimate the correlation between p-wave velocity and stiffness of rocks. As a result, p-wave velocities of rocks are decided for each status of rocks. The 3-D modeling results showed an accurate outline of the actual slope and p-wave velocity distribution. Based on a Kriging technique, p-wave velocity distribution was used to analyze the earth-volume and the total volume of rocks was calculated as 79,444 m3. This value was similar to the calculated total earth-volume used in civil engineering although the volume for each rock types was calculated differently. However, the calculation method traditionally used in civil engineering seemed to have some errors due to the ...
TL;DR: The improved SPH algorithm was applied to simulate 3D water discharge and the result shows that the algorithm satisfies Bernulli's theorem with acceptable degree of errors.
Abstract: Computational load and numerical instability are two of the most challenging problems in enlarging the scale of smoothed particle hydrodynamics (SPH) simulation and applying SPH to a 3D problem. In this work, a study on advanced algorithm is conducted for large-scale SPH simulation in 3D. To reduce computational cost, the concept of a grid-based, linked-list algorithm was adopted and tested by being applied to solve a rotating cylinder problem. The result shows that the size of the search grid should be above or equal to the size of the support domain to obtain a stable and accurate solution. A zero order filtering algorithm is applied for reduction of noise signal in density and pressure for every 50 steps. Consequently, noise signal in density and pressure is apparently decreased and potential instability of computation has decreased. The improved SPH algorithm was applied to simulate 3D water discharge and the result shows that the algorithm satisfies Bernulli's theorem with acceptable degree of errors.
TL;DR: In this article, an orientation biogeochemical exploration was applied in the vicinity of Ildong Fe-Pb-Zn skarn deposits in Korea, where a total of 12 rock, 64 soil and 320 plant samples (including three species such as Daimyo oak leaves/branches (Quercus dentata), Ash tree leaves and branches (Fraxinus rhynchophylla Hance) and Japanese red pine leaves (Pinus densiflora Siebold & Zucc.)) were collected and analysed.
Abstract: Orientation biogeochemical exploration was applied in the vicinity of Ildong Fe-Pb-Zn skarn deposits in Korea. Sampling was conducted along four traverse lines and control areas. A total of 12 rock, 64 soil and 320 plant samples (including three species such as Daimyo oak leaves/branches (Quercus dentata), Ash tree leaves/branches (Fraxinus rhynchophylla Hance) and Japanese red pine leaves (Pinus densiflora Siebold & Zucc.)) were collected and analysed. The content of Cu, Pb, Zn, Mn, Cd, As and Mo in soil from target areas (n = 56) were 2.0–4.5 times higher than those from control areas (n = 8). However, there were no specific contrasts of element content in plant samples (each n = 56) except both for Pb in Q. dentata leaves (0.45–54.93 mg/kg Pb) and branches (0.73–25.89 mg/kg Pb) and Cd in P. densiflora leaves (0.06–4.08 mg/kg Cd). The biological absorption coefficient for each plant sample was low, except for Cd and Mo, which shows 0.214 and 0.149 respectively in P. densiflora. Also, element content in ...
TL;DR: In this article, the authors evaluate the rate of conduction and convection and determine optimum conditions that maximize heat transfer and wettability alteration in the tight matrix of carbonate reservoirs.
Abstract: Carbonate reservoirs contain over 90% of oil within an extremely tight matrix and are usually oil-wet, which makes them unfavorable for oil production During water injection, water does not imbibe into the matrix, but flows preferentially through the fractures, resulting in very low oil recoveries It is proposed that steam or hot water is injected, inducing a wettability change and rendering the matrix water-wet Then, water can move into the matrix by capillary imbibition From this perspective, it is crucial to analyze the contributions of conductive and convective heat transfer during steam injectionThe mechanism of wettability changes is accounted for when steam is injected into carbonate reservoirs The effect of strong capillary pressure in a tight matrix on the oil recovery is also examined The purpose of this study is to evaluate the rate of conduction and convection and to determine optimum conditions that maximize heat transfer and wettability alteration in the tight matrix An analytical so
TL;DR: In this paper, waste dumping sites in Uyo metropolis, Nigeria were selected to assess waste generation and management and their effects on outdoor air quality using in situ portable digital monitors.
Abstract: Waste generation and management has emerged as one of the greatest challenges facing our environment in recent times. In this study, waste dumping sites in Uyo metropolis, Nigeria were selected to assess waste generation and management and their effects on outdoor air quality. Concentrations of gaseous pollutants such as CO, SO2, NO2, HCN, H2S, Cl, NH3 and suspended particulate matter (SPM), as well as heat, noise and radiation, were measured using in situ portable digital monitors. Concentrations of those pollutants varied with location, partly due to variation in the composition of waste dumped and partly due to predominant activities at each site. Results obtained from the study revealed that the concentration of NO2 was highest at SP5 (0.45 ± 0.07), while the concentration of ammonia was highest at SP3 (13.3 ± 0.71 ppm). Concentrations of SO2 at all the sampled locations varied between 0.15 ± 0.07 ppm and 0.45 ± 0.07 ppm. All the sites under study recorded high levels of CO, with a range of 13.5 ± 0.7...