Mineral exploration is done by different methods. Geophysical and geochemical studies are two powerful tools in this field. In integrated studies, the results of each study are used to determine the location of the dr...Mineral exploration is done by different methods. Geophysical and geochemical studies are two powerful tools in this field. In integrated studies, the results of each study are used to determine the location of the drilling boreholes. The purpose of this study is to use field geophysics to calculate the depth of mineral reserve. The study area is located 38 km from Zarand city called Jalalabad iron mine. In this study, gravimetric data were measured and mineral depth was calculated using the Euler method. 1314 readings have been performed in this area. The rocks of the region include volcanic and sedimentary. The source of the mineralization in the area is hydrothermal processes. After gravity measuring in the region, the data were corrected, then various methods such as anomalous map remaining in levels one and two, upward expansion, first and second-degree vertical derivatives, analytical method, and analytical signal were drawn, and finally, the depth of the deposit was estimated by Euler method. As a result, the depth of the mineral deposit was calculated to be between 20 and 30 meters on average.展开更多
The main objective of this study is to improve the geoid by GPS/leveling data in Egypt.Comparisons of the gravimetric geoid with GPS/leveling data have been performed.On the basis of a gravimetric geoid fitted to GPS/...The main objective of this study is to improve the geoid by GPS/leveling data in Egypt.Comparisons of the gravimetric geoid with GPS/leveling data have been performed.On the basis of a gravimetric geoid fitted to GPS/leveling by the least square method,a smoothed geoid was obtained.A high_resolution geoid in Egypt was computed with a 2.5′×2.5′ grid by combining the data set of 2 600 original point gravity values,30″×30″ resolution Digital Terrain Model (DTM) grid and the spherical harmonic model EGM96.The method of computation involved the strict evaluation of the Stokes integral with 1D_FFT.The standard deviation of the difference between the gravimetric and the GPS/leveling geoid heights is ±0.47 m.The standard deviation after fitting of the gravimetric geoid to the GPS/leveling points is better than ±13 cm.In the future we will try to improve our geoid results in Egypt by increasing the density of gravimetric coverage.展开更多
We investigate sedimentological and tectonic processes at the central High Atlas, in order to understand their functioning and to build a geodynamic model that placed the area in its current geological frame.The analy...We investigate sedimentological and tectonic processes at the central High Atlas, in order to understand their functioning and to build a geodynamic model that placed the area in its current geological frame.The analysis used here is based on the numerical enhancement of a Landsat image where the main goal is to map surface sedimentary deposits throughout the central High Atlas in order to delimit the large geological structures. The sediment distribution throughout central High Atlas indicates that this one is a large tectonic subsiding basin, where the ongoing tectonic events and the geodynamical evolution remain to be explained by other prospecting techniques.3-D structure velocities obtained by local seismic tomography and enhancement techniques of gravimetric anomalies are used to explore and define deep structure beneath the central High Atlas. The goal is to establish the evolution of the deep structure related to the geodynamical processes. Modest crustal thickness variation beneath the central High Atlas(~20-~40 km) define by local tomography and gravimetric anomalies, confirms that, a major part of the lower crust is detached into the lithosphere by delamination. Gravimetric anomaly, local seismic tomography and vertical cross sections throughout the central High Atlas, suggest that the lower crust detached is related to the broken slab of remain northward subduction beneath High and Middle Atlas. Meanwhile, extrusions of heated Asthenosphere materials induce the rifting stage concomitant to tectonic subsidence of the basin.展开更多
<span style="font-family:Verdana;">The determination of geoid models with great precision (centimeter) was always at the center of interest in geodesy research [<a href="#ref1">1</a&...<span style="font-family:Verdana;">The determination of geoid models with great precision (centimeter) was always at the center of interest in geodesy research [<a href="#ref1">1</a>] [<a href="#ref2">2</a>]. One of the most used methods to calculate the geoid model is the method called Remove-Compute-Restore (R-C-R). This method applies the stokes’ integral formula by the use of short, medium and long wavelength information via the three main stages R-C-R. The GravSoft software implemented by [<a href="#ref3">3</a>] was used for this study. Geodetic heights, a digital terrain model (SRTM) and leveled GPS points were used as inputs. The geoid modeling was carried out on the North region of Tunisia (Grand Tunis and Bizerte) on an area of 83 × 83 km. The accuracy of the quasi-geoid provisional reached 3.1 cm.</span>展开更多
Airborne particulate matter (PM) filter sample processing is susceptible to error and can present issues associated with organizing samples, tracking data, and maintaining weighing conditions. While filter weighing fa...Airborne particulate matter (PM) filter sample processing is susceptible to error and can present issues associated with organizing samples, tracking data, and maintaining weighing conditions. While filter weighing facilities should implement robust quality assurance and control checks to ensure that data collection is accurate and filter storage is secure, mistakes and accidents can still occur that compromise valuable data. This paper presents a novel approach to PM filter sample processing that allows for data validation or data recovery while ensuring data integrity. The technique approximates the original, unused pre-sampling weight of polytetrafluoroethylene (PTFE) filters after PM collection to determine PM mass-deposition (MD). The method describes the extraction of PM loaded on PTFE filters via sonication in relatively non-toxic solvents, methanol and distilled water. The extraction method is compared to the standard gravimetric PM MD determination method for a set of 265 PTFE filters with mean post-sampling filter mass of 116 ± 3.6 mg, mean estimated PM MD using the standard method of 367 ± 589 μg, and mean estimated PM MD using the extraction method of 371 ± 589 μg. A Deming regression comparison of the two methods yields a slope of 0.9983 and a Pearson’s r of 0.999. A Bland-Altman assessment of the percent and absolute differences between the two methods shows the limits of agreement between 32.5% and 25.5% and -61.9 and 50.1 μg, respectively. The 99% confidence interval of the mean difference in mass deposition between the two methods is -5.8 ± 4.5 μg. These data demonstrate that estimating pre-sampling PTFE filter mass by extracting PM from sampled filters is a viable technique for gravimetric filter analysis. This method is of use in recovering pre-sampling filter weights that have been lost, incorrectly measured, or otherwise compromised.展开更多
We used the geological map and published rock density measurements to compile the digital rock density model for the Hong Kong territories.We then estimated the average density for the whole territory.According to our...We used the geological map and published rock density measurements to compile the digital rock density model for the Hong Kong territories.We then estimated the average density for the whole territory.According to our result,the rock density values in Hong Kong vary from 2101 to 2681 kg·m^(-3).These density values are typically smaller than the average density of 2670 kg·m^(-3),often adopted to represent the average density of the upper continental crust in physical geodesy and gravimetric geophysics applications.This finding reflects that the geological configuration in Hong Kong is mainly formed by light volcanic formations and lava flows with overlying sedimentary deposits at many locations,while the percentage of heavier metamorphic rocks is very low(less than 1%).This product will improve the accuracy of a detailed geoid model and orthometric heights.展开更多
Emerging as an outperformed class of metal-organic frameworks(MOFs),square-octahedron(soc)topology MOFs(soc-MOFs)feature superior properties of high porosity,large gas storage capacity,and excellent thermal/chemical s...Emerging as an outperformed class of metal-organic frameworks(MOFs),square-octahedron(soc)topology MOFs(soc-MOFs)feature superior properties of high porosity,large gas storage capacity,and excellent thermal/chemical stability.We report here an iron based soc-MOF,denoted as Fe-pbpta(H4pbpta=4,4',4'',4'''-(1,4-phenylenbis(pyridine-4,2-6-triyl))-tetrabenzoic acid)possessing a very high Brunauer,Emmett and Teller(BET)surface area of 4,937 m2/g and a large pore volume of 2.15 cm3/g.The MOF demonstrates by far the highest gravimetric uptake of 369 cm3(STP)/g under the DOE operational storage conditions(35 bar and 298 K)and a high volumetric deliverable capacity of 192 cc/cc at 298 K and 65 bar.Furthermore,Fe-pbpta exhibits high thermal and aqueous stability making it a promising candidate for on-board methane storage.展开更多
The soil-water characteristic curve(SWCC)is often used to estimate unsaturated soil properties(e.g.strength,permeability,volume change,solute and thermal diffusivity).The SWCC of soil samples is significantly affected...The soil-water characteristic curve(SWCC)is often used to estimate unsaturated soil properties(e.g.strength,permeability,volume change,solute and thermal diffusivity).The SWCC of soil samples is significantly affected by cyclic wetting-drying.To examine how water content and cyclic wetting-drying affect the SWCC of disintegrated carbonaceous mudstone(DCM),SWCC tests were implemented using a pressure-plate apparatus.In addition,SWCC models for DCM considering the initial gravimetric water content and cyclic wetting-drying were developed.The test results showed that the volumetric water content(θ)of the DCM first decreased rapidly and then became stable as matric suction(s)increased.The initial water content affected the SWCC by altering the pore structure of the DCM.For a given number of wetting-drying cycles,the higher the initial water content,the higher the stabilizedθ.At a given s value,θdecreased as the number of wetting-drying cycles increased,which suggests that cyclic wetting-drying reduces the water-holding capacity of DCM.The Gardner model for DCM was constructed considering initial water content and cyclic wetting-drying,and was effective at describing and predicting the SWCC model for DCM.展开更多
The properly-posedness of the nonlinear fixed gravimetric boundary value problem is shown with the help of nonlinear functional analysis and a new iterative method to solve the problem is also given, where each step o...The properly-posedness of the nonlinear fixed gravimetric boundary value problem is shown with the help of nonlinear functional analysis and a new iterative method to solve the problem is also given, where each step of the iterative program is reduced to solving one and the same kind of oblique derivative boundary value problem with the same type. Furthermore, the convergence of the iterative program is proved with Schauder estimate of elliptic differential equation.展开更多
The geodynamic hazards and risk assessment at the Karachaganak oil,gas,and condensate field(KOGCF)were explored on the northern board of the Pre-Caspian Basin to predict the consequences of the longterm exploitation o...The geodynamic hazards and risk assessment at the Karachaganak oil,gas,and condensate field(KOGCF)were explored on the northern board of the Pre-Caspian Basin to predict the consequences of the longterm exploitation of this field.We integrate multiple measurements,including repeated accurate leveling,Global Positioning System(GPS)measurements,and high precision gravimetric and seismological monitoring at the KOGCF.The results of geodynamic monitoring at the KOGCF for the first time made it possible to prove noticeable seismic deformation processes in the sedimentary cover under the influence of hydrocarbon production.The vertical displacements and horizontal movement along faults,changes in local gravity anomalies,and earthquake sources at depths comparable to hydrocarbon production intervals at the KOGCF have been identified.The maximum amplitudes of modern vertical movement of the earth’s surface and the minimum values of the differently oriented horizontal movement were revealed within the projection on the ground surface of the crest of the carbonate massif(Upper Devonian-Lower Permian age).The results suggest the expansion of uneven compression in the crest of the KOGCF while tension processes occur on its periphery.There is a decrease in gravity variations in relation to the slopes of this massif in areas with active hydrocarbon production.An extended zone of high-gradient steps of AGa anomalies,spatially coinciding with the position of fault zones,is mapped along the periphery of the contour of production wells.In the northeastern part of the KOGCF,seismic events were registered practically in the depth intervals of the productive horizons from which hydrocarbons are produced.A spatial relationship between the seismic events and the anomalous deformation activity in the northeast KOGCF has been revealed.Consequently,the field development has provoked both intense deformation of the earth’s surface and weak local seismicity.展开更多
The Global Navigation Satellite System(GNSS)positioning method has been significantly developed in geodetic surveying.However,the height obtained through GNSS observations is given in a geodetic height system that nee...The Global Navigation Satellite System(GNSS)positioning method has been significantly developed in geodetic surveying.However,the height obtained through GNSS observations is given in a geodetic height system that needs to be converted to orthometric height for engineering applications.Information on geoid height,which can be calculated using the global geopotential mode,is required to convert such GNSS observations into orthometric height.However,its accuracy is still insufficient for most engineering purposes.Therefore,a reliable geoid model is essential,especially in areas growing fast,e.g.,the central part of Java,Indonesia.In this study,we modeled the local geoid model in the central part of Java,Indonesia,using terrestrial-based gravity observations.The Stokes'formula with the second Helmert's condensation method under the Remove-Compute-Restore approach was implemented to model the geoid.The comparison between our best-performing geoid model and GNSS/leveling observations showed that the standard deviation of the geoid height differences was estimated to be 4.4 cm.This geoid result outperformed the commonly adopted global model of EGM2008 with the estimated standard deviation of geoid height differences of 10.7 cm.展开更多
Studies carried out in the Gontougo region aimed to describe the physical and petro-structural properties of the Tarkwaian formations of northeastern Côte d’Ivoire. The methodology developed is focused on the on...Studies carried out in the Gontougo region aimed to describe the physical and petro-structural properties of the Tarkwaian formations of northeastern Côte d’Ivoire. The methodology developed is focused on the one hand on the gravimetric geophysical method and on the other hand, on petro-structural studies. The geophysical results highlighted two gravimetric facies characterized respectively by high density (ΔBg > 121 mGal) and low density (ΔBg < 114 mGal) anomalies. From a lithological point of view, the denser domains are made up of intrusive rocks dominated by granodiorites and tonalites cutting low density facies composed of Tarkwaian formations (polygenic conglomerates and arkosic sandstones) and volcanics (tuffs and cinerites). Structurally, these different lithological groups are affected by brittle (fractures, faults, strike-slip) and ductile (folds, schistosities and mineral lineations) deformations. These structures are mainly oriented NNW-SSW, WNW-ESE and NE-SW. The description of the sulphide minerals reveals a style of gold mineralization of the Tarkwaian formations.展开更多
The combustion behavior of typical components of MSW was examined with a thermal gravimetric analyzer (TGA). The experiments were done over the temperature range of room temperature to 1000 篊 at a heating rate of 10 ...The combustion behavior of typical components of MSW was examined with a thermal gravimetric analyzer (TGA). The experiments were done over the temperature range of room temperature to 1000 篊 at a heating rate of 10 篊/min and in an oxidizing atmosphere. The results indicated that the entire weight loss process of each typical component of MSW consists of one to three distinct combustion stages. The combustion of typical components of MSW could be modeled by one to three independent reactions. The corresponding parameters of typical components of MSW such as activation energy, pre-exponential factor, and reaction order were determined. The calculated results using the comprehensive kinetic model composed of one to three independent and consecutive reactions, agreed well with experimental results.展开更多
Background:According to the traditional Chinese medicine theory,the common processing methods for Ruxiang(frankincense)include stir-frying processing and vinegar processing.Methods:With network pharmacology and therma...Background:According to the traditional Chinese medicine theory,the common processing methods for Ruxiang(frankincense)include stir-frying processing and vinegar processing.Methods:With network pharmacology and thermal analysis methods,we selected and identified the main and irritating ingredients,established the pyrolysis characteristic parameters for identifying frankincense quality,quantified the starting and optimum temperature limits for processing frankincense,and analyzed the influences of processing adjuvants(vinegar)on combustion pyrolysis characteristics of frankincense.By applying Fourier transformation infrared spectrometry,high performance liquid chromatography,gas chromatography and UV-visible spectrometry,we evaluated the processing technology developed in our study of frankincense and its processed products.Results:Based on network pharmacology,we can find that the classical compounds of essential oil are the main pharmacodynamics components of frankincense possessing the anti-inflammatory,analgesia,anti-tumor,anti-ulcer and ant-inflammatory bowel disease effects.The pyrolysis combustion rate peaks of frankincense at 285.27±7.05℃and 476.99±13.46℃were the characteristic peaks used to identify frankincense quality.The specific temperature of slow-fire processing,including the vinegar processing and stir-frying processing,was 148.72±5.09℃.Heating for 5.67±0.98 min after reaching processing temperature was needed for processing frankincense with vinegar.The kinetics analysis showed that both frankincense and its vinegar mixture exhibited good linear relationships.The feasibility and practicability for our processing technology were verified through the determination of medicinal compounds by Fourier transformation infrared spectrometry,high performance liquid chromatography,gas chromatography and UV.Conclusion:Frankincense essential oils were the main active components of frankincense,which also can be taken as the internal chemical control indexes to judge the quality control and to optimize the processing technology of frankincense.The pyrolysis combustion rate peaks of frankincense at 285.27±7.05℃and 476.99±13.46℃were the characteristic peaks that can be used to identify frankincense quality.The optimum processing conditions of vinegar-processed frankincense with were as follows:with vinegar,20%;heating temperature,148.72±5.09℃;and heating time,5.67±0.98 min.Under these conditions,frankincense essential oil could cause a moderate effect on combustion pyrolysis characteristics to exert its corresponding pharmacological effects.展开更多
The thermal stability and decomposition kinetics of polysuccinimide (PSI) were investigated using analyzer DTG-60 under high purity nitrogen atmosphere at different heating rates (3, 6, 9, 12 K/min). The thermal decom...The thermal stability and decomposition kinetics of polysuccinimide (PSI) were investigated using analyzer DTG-60 under high purity nitrogen atmosphere at different heating rates (3, 6, 9, 12 K/min). The thermal decomposition mechanism of PSI was determined by Coats-Redfern method. The kinetic parameters such as activation energy (E), pre-exponential factor (A) and reaction order (n) were calculated by Flynn-Wall-Ozawa and Kissinger methods. The results show that the thermal decomposition of PSI under nitrogen atmosphere mainly occurs in the temperature range of 619.15-693.15 K, the reaction order (n) was , the activation energy (E) and pre-exponential factor (A) were obtained to be 106.585 kJ/mol and 4.644 × 109 min-1, the integral and differential forms of the thermal decomposition mechanism of PSI were found to be and , respectively. The results play an important role in understanding the thermodynamic properties of polysuccinimide.展开更多
The diffusion coefficient of volatiles in polymer solutions is a crucial parameter to describe the mass transfer efficiency and ability of volatiles.In this research,polyolefin elastomer(POE)was used as a polymer,and ...The diffusion coefficient of volatiles in polymer solutions is a crucial parameter to describe the mass transfer efficiency and ability of volatiles.In this research,polyolefin elastomer(POE)was used as a polymer,and cyclohexane was used as a volatile.A gravimetric analysis was applied to measure the diffusion coefficient of cyclohexane in POE.The devolatilization rate of the POE-cyclohexane system under different conditions was measured.The effects of temperature,film sample thickness,and initial concentration of volatiles on the devolatilization rate were discussed.Based on the devolatilization rate data,the average diffusion coefficient of cyclohexane in POE was obtained by fitting with a mathematical model.The experimental results indicate that the devolatilization rate increased with increasing temperature and initial concentration of volatiles,but it decreased with increasing sample thickness.As the thickness increased,the overall diffusion resistance increased.As the temperature increased,the molecular movement increased,resulting in the increase of average diffusion coefficient.The relationship between the diffusion coefficient of the POE-cyclohexane system and temperature follows the Arrhenius law.The diffusion activation energy E=6201.73 J/mol,and the pre-exponential factor of the diffusion coefficient D0=2.64×10^(-10) m^(2)/s.This work can provide basic data for exploring the devolatilization of POE polymers and serves as a useful reference for enhancing the effect of devolatilization.展开更多
Corrosion inhibition characteristics of two biomass derived extracts from outer leaves of Brassica oleracea (BO) and Citrus paradise mesocarps (CPM) on pipeline steel were investigated using modified gravimetric metho...Corrosion inhibition characteristics of two biomass derived extracts from outer leaves of Brassica oleracea (BO) and Citrus paradise mesocarps (CPM) on pipeline steel were investigated using modified gravimetric method at ambient temperature (28 ± °C). Petroleum pipeline water was used to simulate a pseudo-anaerobic corrosion cell. The result obtained showed that corrosion was a continuous process in the closed system, while BO and CPM showed near equivalence corrosion inhibition efficiency of 91.45% and 89.44% respectively at the concentrations studied. The thermodynamic data suggests inhibition to be through molecular adsorption on metal surface.展开更多
The dose-response relationship for asbestos exposure in a chrysotile product factory was studied. The past gravimetric dust concentration values, obtained from different worksites, were converted into fiber concentrat...The dose-response relationship for asbestos exposure in a chrysotile product factory was studied. The past gravimetric dust concentration values, obtained from different worksites, were converted into fiber concentration values according to conversion factors that were worked out by simultaneous sampling in this study. The conversions were made so that exposure could be expressed in fiber-years (f-yr). Asbestosis was diagnosed on the basis of chest radiographs and occupational histories. Cumulative dust exposure (f-yr) was calculated up to the date of diagnosis for asbestosis patients, and up to September 1982 for the remaining workers. A dose-response relationship expressed as fiber-years exposed vs cumulative prevalence of asbestosis was established by the life table method on the basis of these data. Predicted 3 and 1% prevalence of asbestosis corresponded to 43 and 22 f-yr exposure, respectively. Considering that a worker can work for 35 years, these doses are commensurate with dust concentrations of 1.22 and 0.63 f/ml, respectively. It is recommended that 1 f/ml be taken as the maximum allowable concentration of airborne asbestos dust for the workplace with an anticipated prevalence of about 2% asbestosis after 35 years of exposure. 1990 Academic Press, Inc.展开更多
The single crystal of the complex [Sc（NO<sub>3</sub>）<sub>3</sub>（H<sub>2</sub>O）<sub>2</sub>]·（15C5） has been prepared in acetonitrile.Thenew complex has bee...The single crystal of the complex [Sc（NO<sub>3</sub>）<sub>3</sub>（H<sub>2</sub>O）<sub>2</sub>]·（15C5） has been prepared in acetonitrile.Thenew complex has been characterized by elemental analysis,IR spectra,solubility and molar conductancemeasurements.The structure of the complex is determined by single crystal X-ray diffraction analysis.展开更多
Using first-principles calculations based on density functional theory(DFT),we investigate the potential hydrogen storage capacity of the Na-decorated net-Y single layer nanosheet.For double-side Na decoration,the ave...Using first-principles calculations based on density functional theory(DFT),we investigate the potential hydrogen storage capacity of the Na-decorated net-Y single layer nanosheet.For double-side Na decoration,the average binding energy is 1.54 eV,which is much larger than the cohesive energy of 1.13 eV for bulk Na.A maximum of four H2 molecules can be adsorbed around each Na with average adsorption energies of 0.25–0.32 eV/H2.Also,H2 storage gravimetric of 8.85 wt%is obtained,and this meets the U.S.Department of Energy(DOE)ultimate target.These results are instrumental in seeking a promising hydrogen energy carrier.展开更多
文摘Mineral exploration is done by different methods. Geophysical and geochemical studies are two powerful tools in this field. In integrated studies, the results of each study are used to determine the location of the drilling boreholes. The purpose of this study is to use field geophysics to calculate the depth of mineral reserve. The study area is located 38 km from Zarand city called Jalalabad iron mine. In this study, gravimetric data were measured and mineral depth was calculated using the Euler method. 1314 readings have been performed in this area. The rocks of the region include volcanic and sedimentary. The source of the mineralization in the area is hydrothermal processes. After gravity measuring in the region, the data were corrected, then various methods such as anomalous map remaining in levels one and two, upward expansion, first and second-degree vertical derivatives, analytical method, and analytical signal were drawn, and finally, the depth of the deposit was estimated by Euler method. As a result, the depth of the mineral deposit was calculated to be between 20 and 30 meters on average.
文摘The main objective of this study is to improve the geoid by GPS/leveling data in Egypt.Comparisons of the gravimetric geoid with GPS/leveling data have been performed.On the basis of a gravimetric geoid fitted to GPS/leveling by the least square method,a smoothed geoid was obtained.A high_resolution geoid in Egypt was computed with a 2.5′×2.5′ grid by combining the data set of 2 600 original point gravity values,30″×30″ resolution Digital Terrain Model (DTM) grid and the spherical harmonic model EGM96.The method of computation involved the strict evaluation of the Stokes integral with 1D_FFT.The standard deviation of the difference between the gravimetric and the GPS/leveling geoid heights is ±0.47 m.The standard deviation after fitting of the gravimetric geoid to the GPS/leveling points is better than ±13 cm.In the future we will try to improve our geoid results in Egypt by increasing the density of gravimetric coverage.
基金supported by the Institut Scientifique, Rabat, Morocco
文摘We investigate sedimentological and tectonic processes at the central High Atlas, in order to understand their functioning and to build a geodynamic model that placed the area in its current geological frame.The analysis used here is based on the numerical enhancement of a Landsat image where the main goal is to map surface sedimentary deposits throughout the central High Atlas in order to delimit the large geological structures. The sediment distribution throughout central High Atlas indicates that this one is a large tectonic subsiding basin, where the ongoing tectonic events and the geodynamical evolution remain to be explained by other prospecting techniques.3-D structure velocities obtained by local seismic tomography and enhancement techniques of gravimetric anomalies are used to explore and define deep structure beneath the central High Atlas. The goal is to establish the evolution of the deep structure related to the geodynamical processes. Modest crustal thickness variation beneath the central High Atlas(~20-~40 km) define by local tomography and gravimetric anomalies, confirms that, a major part of the lower crust is detached into the lithosphere by delamination. Gravimetric anomaly, local seismic tomography and vertical cross sections throughout the central High Atlas, suggest that the lower crust detached is related to the broken slab of remain northward subduction beneath High and Middle Atlas. Meanwhile, extrusions of heated Asthenosphere materials induce the rifting stage concomitant to tectonic subsidence of the basin.
文摘<span style="font-family:Verdana;">The determination of geoid models with great precision (centimeter) was always at the center of interest in geodesy research [<a href="#ref1">1</a>] [<a href="#ref2">2</a>]. One of the most used methods to calculate the geoid model is the method called Remove-Compute-Restore (R-C-R). This method applies the stokes’ integral formula by the use of short, medium and long wavelength information via the three main stages R-C-R. The GravSoft software implemented by [<a href="#ref3">3</a>] was used for this study. Geodetic heights, a digital terrain model (SRTM) and leveled GPS points were used as inputs. The geoid modeling was carried out on the North region of Tunisia (Grand Tunis and Bizerte) on an area of 83 × 83 km. The accuracy of the quasi-geoid provisional reached 3.1 cm.</span>
文摘Airborne particulate matter (PM) filter sample processing is susceptible to error and can present issues associated with organizing samples, tracking data, and maintaining weighing conditions. While filter weighing facilities should implement robust quality assurance and control checks to ensure that data collection is accurate and filter storage is secure, mistakes and accidents can still occur that compromise valuable data. This paper presents a novel approach to PM filter sample processing that allows for data validation or data recovery while ensuring data integrity. The technique approximates the original, unused pre-sampling weight of polytetrafluoroethylene (PTFE) filters after PM collection to determine PM mass-deposition (MD). The method describes the extraction of PM loaded on PTFE filters via sonication in relatively non-toxic solvents, methanol and distilled water. The extraction method is compared to the standard gravimetric PM MD determination method for a set of 265 PTFE filters with mean post-sampling filter mass of 116 ± 3.6 mg, mean estimated PM MD using the standard method of 367 ± 589 μg, and mean estimated PM MD using the extraction method of 371 ± 589 μg. A Deming regression comparison of the two methods yields a slope of 0.9983 and a Pearson’s r of 0.999. A Bland-Altman assessment of the percent and absolute differences between the two methods shows the limits of agreement between 32.5% and 25.5% and -61.9 and 50.1 μg, respectively. The 99% confidence interval of the mean difference in mass deposition between the two methods is -5.8 ± 4.5 μg. These data demonstrate that estimating pre-sampling PTFE filter mass by extracting PM from sampled filters is a viable technique for gravimetric filter analysis. This method is of use in recovering pre-sampling filter weights that have been lost, incorrectly measured, or otherwise compromised.
基金supported by the Hong Kong GRF RGC project 15217222:“Modernization of the leveling network in the Hong Kong territories.”。
文摘We used the geological map and published rock density measurements to compile the digital rock density model for the Hong Kong territories.We then estimated the average density for the whole territory.According to our result,the rock density values in Hong Kong vary from 2101 to 2681 kg·m^(-3).These density values are typically smaller than the average density of 2670 kg·m^(-3),often adopted to represent the average density of the upper continental crust in physical geodesy and gravimetric geophysics applications.This finding reflects that the geological configuration in Hong Kong is mainly formed by light volcanic formations and lava flows with overlying sedimentary deposits at many locations,while the percentage of heavier metamorphic rocks is very low(less than 1%).This product will improve the accuracy of a detailed geoid model and orthometric heights.
基金the U.S.Department of Energy's Office of Energy Efficiency and Renewable Energy under the Hydrogen and Fuel Cell Technologies and Vehicle Technologies Offices under Award Number DE-EE0008812.S.K.acknowledges the financial support from the University Grants Commission(UGC),New Delhi,India(No.F 5-80/2014(IC)).ChemMatCARS Sector 15 is principally supported by the Divisions of Chemistry(CHE)and Materials Research(DMR),National Science Foundation,under Grant Number NSF/CHE-1346572.Use of the Advanced Photon Source,an Office of Science User Facility operated for the U.S.Department of Energy(DOE)Office of Science by Argonne National Laboratory,was supported by the U.S.DOE under Contract No.DE-AC02-06CH11357.G.V.would further like to acknowledge Jason Exley(Sales Engineer,Micromeritics USA)for help and support provided with the measurements and the HKUST reference data.
文摘Emerging as an outperformed class of metal-organic frameworks(MOFs),square-octahedron(soc)topology MOFs(soc-MOFs)feature superior properties of high porosity,large gas storage capacity,and excellent thermal/chemical stability.We report here an iron based soc-MOF,denoted as Fe-pbpta(H4pbpta=4,4',4'',4'''-(1,4-phenylenbis(pyridine-4,2-6-triyl))-tetrabenzoic acid)possessing a very high Brunauer,Emmett and Teller(BET)surface area of 4,937 m2/g and a large pore volume of 2.15 cm3/g.The MOF demonstrates by far the highest gravimetric uptake of 369 cm3(STP)/g under the DOE operational storage conditions(35 bar and 298 K)and a high volumetric deliverable capacity of 192 cc/cc at 298 K and 65 bar.Furthermore,Fe-pbpta exhibits high thermal and aqueous stability making it a promising candidate for on-board methane storage.
基金the financial support of the National Natural Science Foundation of China(Grant Nos 51838001,51878070,51578079,51678074,51908069 and 51908073)the Special Funds for the Construction of Innovative Provinces in Hunan,China(Grant No.2019SK2171)+1 种基金Changsha Outstanding Innovative Youth Training Program(Grant No.kq1905043)the Double First-Class Scientific Research International Cooperation Expansion Project at Changsha University of Science&Technology(Grant No.2019IC04).
文摘The soil-water characteristic curve(SWCC)is often used to estimate unsaturated soil properties(e.g.strength,permeability,volume change,solute and thermal diffusivity).The SWCC of soil samples is significantly affected by cyclic wetting-drying.To examine how water content and cyclic wetting-drying affect the SWCC of disintegrated carbonaceous mudstone(DCM),SWCC tests were implemented using a pressure-plate apparatus.In addition,SWCC models for DCM considering the initial gravimetric water content and cyclic wetting-drying were developed.The test results showed that the volumetric water content(θ)of the DCM first decreased rapidly and then became stable as matric suction(s)increased.The initial water content affected the SWCC by altering the pore structure of the DCM.For a given number of wetting-drying cycles,the higher the initial water content,the higher the stabilizedθ.At a given s value,θdecreased as the number of wetting-drying cycles increased,which suggests that cyclic wetting-drying reduces the water-holding capacity of DCM.The Gardner model for DCM was constructed considering initial water content and cyclic wetting-drying,and was effective at describing and predicting the SWCC model for DCM.
基金Project supported by the National Natural Science Foundaion of China.
文摘The properly-posedness of the nonlinear fixed gravimetric boundary value problem is shown with the help of nonlinear functional analysis and a new iterative method to solve the problem is also given, where each step of the iterative program is reduced to solving one and the same kind of oblique derivative boundary value problem with the same type. Furthermore, the convergence of the iterative program is proved with Schauder estimate of elliptic differential equation.
文摘The geodynamic hazards and risk assessment at the Karachaganak oil,gas,and condensate field(KOGCF)were explored on the northern board of the Pre-Caspian Basin to predict the consequences of the longterm exploitation of this field.We integrate multiple measurements,including repeated accurate leveling,Global Positioning System(GPS)measurements,and high precision gravimetric and seismological monitoring at the KOGCF.The results of geodynamic monitoring at the KOGCF for the first time made it possible to prove noticeable seismic deformation processes in the sedimentary cover under the influence of hydrocarbon production.The vertical displacements and horizontal movement along faults,changes in local gravity anomalies,and earthquake sources at depths comparable to hydrocarbon production intervals at the KOGCF have been identified.The maximum amplitudes of modern vertical movement of the earth’s surface and the minimum values of the differently oriented horizontal movement were revealed within the projection on the ground surface of the crest of the carbonate massif(Upper Devonian-Lower Permian age).The results suggest the expansion of uneven compression in the crest of the KOGCF while tension processes occur on its periphery.There is a decrease in gravity variations in relation to the slopes of this massif in areas with active hydrocarbon production.An extended zone of high-gradient steps of AGa anomalies,spatially coinciding with the position of fault zones,is mapped along the periphery of the contour of production wells.In the northeastern part of the KOGCF,seismic events were registered practically in the depth intervals of the productive horizons from which hydrocarbons are produced.A spatial relationship between the seismic events and the anomalous deformation activity in the northeast KOGCF has been revealed.Consequently,the field development has provoked both intense deformation of the earth’s surface and weak local seismicity.
文摘The Global Navigation Satellite System(GNSS)positioning method has been significantly developed in geodetic surveying.However,the height obtained through GNSS observations is given in a geodetic height system that needs to be converted to orthometric height for engineering applications.Information on geoid height,which can be calculated using the global geopotential mode,is required to convert such GNSS observations into orthometric height.However,its accuracy is still insufficient for most engineering purposes.Therefore,a reliable geoid model is essential,especially in areas growing fast,e.g.,the central part of Java,Indonesia.In this study,we modeled the local geoid model in the central part of Java,Indonesia,using terrestrial-based gravity observations.The Stokes'formula with the second Helmert's condensation method under the Remove-Compute-Restore approach was implemented to model the geoid.The comparison between our best-performing geoid model and GNSS/leveling observations showed that the standard deviation of the geoid height differences was estimated to be 4.4 cm.This geoid result outperformed the commonly adopted global model of EGM2008 with the estimated standard deviation of geoid height differences of 10.7 cm.
文摘Studies carried out in the Gontougo region aimed to describe the physical and petro-structural properties of the Tarkwaian formations of northeastern Côte d’Ivoire. The methodology developed is focused on the one hand on the gravimetric geophysical method and on the other hand, on petro-structural studies. The geophysical results highlighted two gravimetric facies characterized respectively by high density (ΔBg > 121 mGal) and low density (ΔBg < 114 mGal) anomalies. From a lithological point of view, the denser domains are made up of intrusive rocks dominated by granodiorites and tonalites cutting low density facies composed of Tarkwaian formations (polygenic conglomerates and arkosic sandstones) and volcanics (tuffs and cinerites). Structurally, these different lithological groups are affected by brittle (fractures, faults, strike-slip) and ductile (folds, schistosities and mineral lineations) deformations. These structures are mainly oriented NNW-SSW, WNW-ESE and NE-SW. The description of the sulphide minerals reveals a style of gold mineralization of the Tarkwaian formations.
文摘The combustion behavior of typical components of MSW was examined with a thermal gravimetric analyzer (TGA). The experiments were done over the temperature range of room temperature to 1000 篊 at a heating rate of 10 篊/min and in an oxidizing atmosphere. The results indicated that the entire weight loss process of each typical component of MSW consists of one to three distinct combustion stages. The combustion of typical components of MSW could be modeled by one to three independent reactions. The corresponding parameters of typical components of MSW such as activation energy, pre-exponential factor, and reaction order were determined. The calculated results using the comprehensive kinetic model composed of one to three independent and consecutive reactions, agreed well with experimental results.
基金funded by Natural Science Foundation of Shanxi Province,China(Grant No.2014ZD0302)Science and Technology Innovation Ability Cultivation Plan of Shanxi University of Chinese Medicine(2019PY-154)Research Project of Health Commission of Shanxi Province(2019092)。
文摘Background:According to the traditional Chinese medicine theory,the common processing methods for Ruxiang(frankincense)include stir-frying processing and vinegar processing.Methods:With network pharmacology and thermal analysis methods,we selected and identified the main and irritating ingredients,established the pyrolysis characteristic parameters for identifying frankincense quality,quantified the starting and optimum temperature limits for processing frankincense,and analyzed the influences of processing adjuvants(vinegar)on combustion pyrolysis characteristics of frankincense.By applying Fourier transformation infrared spectrometry,high performance liquid chromatography,gas chromatography and UV-visible spectrometry,we evaluated the processing technology developed in our study of frankincense and its processed products.Results:Based on network pharmacology,we can find that the classical compounds of essential oil are the main pharmacodynamics components of frankincense possessing the anti-inflammatory,analgesia,anti-tumor,anti-ulcer and ant-inflammatory bowel disease effects.The pyrolysis combustion rate peaks of frankincense at 285.27±7.05℃and 476.99±13.46℃were the characteristic peaks used to identify frankincense quality.The specific temperature of slow-fire processing,including the vinegar processing and stir-frying processing,was 148.72±5.09℃.Heating for 5.67±0.98 min after reaching processing temperature was needed for processing frankincense with vinegar.The kinetics analysis showed that both frankincense and its vinegar mixture exhibited good linear relationships.The feasibility and practicability for our processing technology were verified through the determination of medicinal compounds by Fourier transformation infrared spectrometry,high performance liquid chromatography,gas chromatography and UV.Conclusion:Frankincense essential oils were the main active components of frankincense,which also can be taken as the internal chemical control indexes to judge the quality control and to optimize the processing technology of frankincense.The pyrolysis combustion rate peaks of frankincense at 285.27±7.05℃and 476.99±13.46℃were the characteristic peaks that can be used to identify frankincense quality.The optimum processing conditions of vinegar-processed frankincense with were as follows:with vinegar,20%;heating temperature,148.72±5.09℃;and heating time,5.67±0.98 min.Under these conditions,frankincense essential oil could cause a moderate effect on combustion pyrolysis characteristics to exert its corresponding pharmacological effects.
文摘The thermal stability and decomposition kinetics of polysuccinimide (PSI) were investigated using analyzer DTG-60 under high purity nitrogen atmosphere at different heating rates (3, 6, 9, 12 K/min). The thermal decomposition mechanism of PSI was determined by Coats-Redfern method. The kinetic parameters such as activation energy (E), pre-exponential factor (A) and reaction order (n) were calculated by Flynn-Wall-Ozawa and Kissinger methods. The results show that the thermal decomposition of PSI under nitrogen atmosphere mainly occurs in the temperature range of 619.15-693.15 K, the reaction order (n) was , the activation energy (E) and pre-exponential factor (A) were obtained to be 106.585 kJ/mol and 4.644 × 109 min-1, the integral and differential forms of the thermal decomposition mechanism of PSI were found to be and , respectively. The results play an important role in understanding the thermodynamic properties of polysuccinimide.
基金The authors wish to express their thanks for the financial support from the Polyolefin Elastomer Technology Development project(2020B-2619).
文摘The diffusion coefficient of volatiles in polymer solutions is a crucial parameter to describe the mass transfer efficiency and ability of volatiles.In this research,polyolefin elastomer(POE)was used as a polymer,and cyclohexane was used as a volatile.A gravimetric analysis was applied to measure the diffusion coefficient of cyclohexane in POE.The devolatilization rate of the POE-cyclohexane system under different conditions was measured.The effects of temperature,film sample thickness,and initial concentration of volatiles on the devolatilization rate were discussed.Based on the devolatilization rate data,the average diffusion coefficient of cyclohexane in POE was obtained by fitting with a mathematical model.The experimental results indicate that the devolatilization rate increased with increasing temperature and initial concentration of volatiles,but it decreased with increasing sample thickness.As the thickness increased,the overall diffusion resistance increased.As the temperature increased,the molecular movement increased,resulting in the increase of average diffusion coefficient.The relationship between the diffusion coefficient of the POE-cyclohexane system and temperature follows the Arrhenius law.The diffusion activation energy E=6201.73 J/mol,and the pre-exponential factor of the diffusion coefficient D0=2.64×10^(-10) m^(2)/s.This work can provide basic data for exploring the devolatilization of POE polymers and serves as a useful reference for enhancing the effect of devolatilization.
文摘Corrosion inhibition characteristics of two biomass derived extracts from outer leaves of Brassica oleracea (BO) and Citrus paradise mesocarps (CPM) on pipeline steel were investigated using modified gravimetric method at ambient temperature (28 ± °C). Petroleum pipeline water was used to simulate a pseudo-anaerobic corrosion cell. The result obtained showed that corrosion was a continuous process in the closed system, while BO and CPM showed near equivalence corrosion inhibition efficiency of 91.45% and 89.44% respectively at the concentrations studied. The thermodynamic data suggests inhibition to be through molecular adsorption on metal surface.
文摘The dose-response relationship for asbestos exposure in a chrysotile product factory was studied. The past gravimetric dust concentration values, obtained from different worksites, were converted into fiber concentration values according to conversion factors that were worked out by simultaneous sampling in this study. The conversions were made so that exposure could be expressed in fiber-years (f-yr). Asbestosis was diagnosed on the basis of chest radiographs and occupational histories. Cumulative dust exposure (f-yr) was calculated up to the date of diagnosis for asbestosis patients, and up to September 1982 for the remaining workers. A dose-response relationship expressed as fiber-years exposed vs cumulative prevalence of asbestosis was established by the life table method on the basis of these data. Predicted 3 and 1% prevalence of asbestosis corresponded to 43 and 22 f-yr exposure, respectively. Considering that a worker can work for 35 years, these doses are commensurate with dust concentrations of 1.22 and 0.63 f/ml, respectively. It is recommended that 1 f/ml be taken as the maximum allowable concentration of airborne asbestos dust for the workplace with an anticipated prevalence of about 2% asbestosis after 35 years of exposure. 1990 Academic Press, Inc.
文摘The single crystal of the complex [Sc（NO<sub>3</sub>）<sub>3</sub>（H<sub>2</sub>O）<sub>2</sub>]·（15C5） has been prepared in acetonitrile.Thenew complex has been characterized by elemental analysis,IR spectra,solubility and molar conductancemeasurements.The structure of the complex is determined by single crystal X-ray diffraction analysis.
基金Project supported by the National Natural Science Foundation of China(Grant No.11804169)the Natural Science Foundation of Jiangsu Province of China(Grant No.BK20180741)
文摘Using first-principles calculations based on density functional theory(DFT),we investigate the potential hydrogen storage capacity of the Na-decorated net-Y single layer nanosheet.For double-side Na decoration,the average binding energy is 1.54 eV,which is much larger than the cohesive energy of 1.13 eV for bulk Na.A maximum of four H2 molecules can be adsorbed around each Na with average adsorption energies of 0.25–0.32 eV/H2.Also,H2 storage gravimetric of 8.85 wt%is obtained,and this meets the U.S.Department of Energy(DOE)ultimate target.These results are instrumental in seeking a promising hydrogen energy carrier.
