The objective of this study is to seek solutions to reduce the impact of buildings on climate change and to promote the use of local bio-sourced or geo-sourced materials for sustainable construction. Different samples...The objective of this study is to seek solutions to reduce the impact of buildings on climate change and to promote the use of local bio-sourced or geo-sourced materials for sustainable construction. Different samples of raw earth from 3 sites were taken in the commune of Mlomp. Geotechnical tests showed that the raw earth samples from sites 2 and 3 have more clay fraction while site 1 contains more sand. The fact of integrating fibers from crushed palm leaves (Borassus aethiopum) (2%, 4% and 6%) into the 3 raw earth samples reduced the mechanical resistance to compression and traction of the 3 raw earths. The experimental results of thermal tests on samples of earth mixtures with crushed Palma leaf fibers show a decrease in thermal conductivity as well as thermal effusivity as the percentages increase (2%, 4% and 6%) of fibers in raw earth for the 3 sites. This shows that this renewable composite material can help improve the thermal insulation of building envelopes.展开更多
Geological maps encode vast amounts of data about rock types,ages,chemistry,orogenic architecture and deep-time history or different tectonic units,yet these are often difficult to extract because of the way different...Geological maps encode vast amounts of data about rock types,ages,chemistry,orogenic architecture and deep-time history or different tectonic units,yet these are often difficult to extract because of the way different geologists portray their results at various scales.To understand orogenesis in 4D,it is essential to uniformly integrate map data,together with geophysical data and deep geochemical mapping(Wang et al.,2023).展开更多
In-situ conversion presents a promising technique for exploiting continental oil shale formations,characterized by highly fractured organic-rich rock.A 3D in-situ conversion model,which incorporates a discrete fractur...In-situ conversion presents a promising technique for exploiting continental oil shale formations,characterized by highly fractured organic-rich rock.A 3D in-situ conversion model,which incorporates a discrete fracture network,is developed using a self-developed thermal-flow-chemical(TFC)simulator.Analysis of the model elucidates the in-situ conversion process in three stages and defines the transformation of fluids into three distinct outcomes according to their end stages.The findings indicate that kerogen decomposition increases fluid pressure,activating fractures and subsequently enhancing permeability.A comprehensive analysis of activated fracture permeability and heating power reveals four distinct production modes,highlighting that increasing heating power correlates with higher cumulative fluid production.Activated fractures,with heightened permeability,facilitate the mobility of heavy oil toward production wells but hinder its cracking,thereby limiting light hydrocarbon production.Additionally,energy efficiency research demonstrates the feasibility of the in-situ conversion in terms of energy utilization,especially when considering the surplus energy from high-fluctuation energy sources such as wind and solar power to provide heating.展开更多
The infrared radiation temperature(IRT)variation concerning stress and crack evolution of rocks is a critical focus in rock mechanics domain and engineering disaster warning.In this paper,a methodology to extract the ...The infrared radiation temperature(IRT)variation concerning stress and crack evolution of rocks is a critical focus in rock mechanics domain and engineering disaster warning.In this paper,a methodology to extract the key IRT features related to stress and crack evolution of loaded rocks is proposed.Specifically,the wavelet denoising and reconstruction in thermal image sequence(WDRTIS)method is employed to eliminate temporal noise in thermal image sequences.Subsequently,the adaptive partition temperature drift correction(APTDC)method is introduced to alleviate temperature drift.On this basis,the spatial noise correction method based on threshold segmentation and adaptive median filtering(OTSU-AMF)is proposed to extract the key IRT features associated with microcracks of loaded rocks.Following temperature drift correction,IRT provides an estimation of the thermoelastic factor in rocks,typically around 5.29×10^(-5) MPa^(-1) for sandstones.Results reveal that the high-temperature concentrated region in cumulative thermal images of crack evolution(TICE)can elucidate the spatiotemporal evolution of localized damage.Additionally,heat dissipation of crack evolution(HDCE)acquired from TICE quantifies the progressive failure process of rocks.The proposed methodology enhances the reliability of IRT monitoring results and provides an innovative approach for conducting research in rock mechanics and monitoring engineering disasters.展开更多
The use of gold as a tracer element for understanding the mode of emplacement of these formations requires a good knowledge of its dynamics. To this end, we have carried out experimental studies to investigate the evo...The use of gold as a tracer element for understanding the mode of emplacement of these formations requires a good knowledge of its dynamics. To this end, we have carried out experimental studies to investigate the evolution of contour states (regular, irregular), surface states (blunt, rough), shape (elongation) and dimension (size). The study of these criteria is carried out on SEM photos of particles, taken before and after the experiment, using Aphelion image processing software. Five experiments were carried out to study the influence of sediment granulometry and water dilution on particle morphological changes. The results of these experiments show that coarse sediments (>1 mm) are largely responsible for morphological changes in gold. They cause fragmentation and/or folding of the particle edges, depending on the magnitude of the impact forces. Strong impacts due to high water dilution cause staking on the particle surface. Fine sediments (<1 mm) slow down particle evolution as they cushion impacts and particles tend to flatten rather than fragment.展开更多
Standards and specifications are the premise of integrated reorganization of science specimen data, and data integration is the core of the reorganization. ETL [1] which is the abbreviation of extract, transform, and ...Standards and specifications are the premise of integrated reorganization of science specimen data, and data integration is the core of the reorganization. ETL [1] which is the abbreviation of extract, transform, and load [2], is very suitable for data integration. Kettle is a kind of ETL software. In this paper, it has been introduced into the integrated reorganization of science specimen data. Multi-source and heterogeneous specimen data are integrated using kettle, and good results have been achieved. It proved the effectiveness of kettle in the integrated reorganization of science specimen data. The application has practical significance, and the method can be referenced when reorganizing other resource data.展开更多
The correlation of the scaled energy,e = Es/ Mo, versus earthquake magnitude, Ms, is studied based on two models: (1) Model 1 based on the use of the time function of the average displacements, with a ω^-2 source ...The correlation of the scaled energy,e = Es/ Mo, versus earthquake magnitude, Ms, is studied based on two models: (1) Model 1 based on the use of the time function of the average displacements, with a ω^-2 source spectrum, across a fault plane; and (2) Model 2 based on the use of the time function of the average displacements, with a ω^-3 source spectrum, across a fault plane. For the second model, there are two cases: (a) As ζ= T, where r is the rise time and T the rupture time, lg(e) - -Ms; and (b) As ζ 〈〈 T, lg(e)- -(1/2)Ms. The second model leads to a negative value of e. This means that Model 2 cannot work for studying the present problem. The results obtained from Model 1 suggest that the source model is a factor, yet not a unique one, in controlling the correlation of e versus Ms.展开更多
Based on eight published plate motion models, we separately estimated the net area changes of tectonic plates and the area change of the solid Earth surface over geological time using the Euler vectors of plates with ...Based on eight published plate motion models, we separately estimated the net area changes of tectonic plates and the area change of the solid Earth surface over geological time using the Euler vectors of plates with determined boundaries. Then, under the context of a currently expanding Earth, we inferred the change rate of the Earth’s mean radius from the estimated net area changes. The results show that the total increases and decreases in the areas of different plates cannot be compensated. Specifically, the area of the Northern Hemisphere decreases while that of the Southern Hemisphere increases, but the net area of the solid Earth surface slightly increases in th computing period(0.01 Ma). For the latest NNRMORVEL56 plate motion model, the area of the Southern Hemisphere increases by 7802 km2 while the area of the Northern Hemisphere decreases by 7711 km^2. This indicates a net area increase of 91 km2 in the solid Earth surface corresponding to an expansion rate of 0.06 mm/a for the Earths mean radius.This result coincides with the slow rate of expansion derived from geodetic measurements and geophysical modeling.展开更多
The observed Earth’s polar motion on decadal time scales has long been conjectured to be excited by the exchange of equatorial angular momentum between the solid mantle and the fluid outer core,via the mechanism of e...The observed Earth’s polar motion on decadal time scales has long been conjectured to be excited by the exchange of equatorial angular momentum between the solid mantle and the fluid outer core,via the mechanism of electromagnetic(EM)core-mantle coupling.However,past estimations of the EM coupling torque from surface geomagnetic observations is too weak to account for the observed decadal polar motion.Our recent estimations from numerical geodynamo simulations have shown the opposite.In this paper,we re-examine in detail the EM coupling mechanism and the properties of the magnetic field in the electrically conducting lower mantle(characterized by a thin D '-layer at the base of the mantle).Our simulations find that the toroidal field in the D'-layer from the induction and convection of the toroidal field in the outer core could be potentially much stronger than that from the advection of the poloidal field in the outer core.The former,however,cannot be inferred from geomagnetic observations at the Earth’s surface,and is missing in previous EM torque estimated from geomagnetic observations.Our deduction suggests further that this field could make the actual EM coupling torque sufficiently strong,at approximately 5×1019 Nm,to excite,and hence explain,the decadal polar motion to magnitude of approximately 10 mas.展开更多
Variations in acceleration and excess pore water pressure during a seismic event are critical early-warning indicators of an impending dam collapse.To assess these variations,the seismic responses for three simplified...Variations in acceleration and excess pore water pressure during a seismic event are critical early-warning indicators of an impending dam collapse.To assess these variations,the seismic responses for three simplified model dams,based on cross-sections through a real earthen dam,were assessed with numerical simulations and centrifuge tests.A normalized root-mean-square error was utilized as a comparison index to assess the closeness between simulated and the recorded values.Assuming that the experimental records are reliable,the reliability of the numerical program was evaluated using this root-mean-square error estimation approach.Explanations for inconsistency between the two approaches are presented.The conclusions are drawn from the results of the three model dams.展开更多
1.Objective The Wenquan Group is one of the important medium-to low-grade metamorphic units within the Wenquan metamorphic complexes which distributes in Chinese segment of the Tianshan Belt,the southern part of the C...1.Objective The Wenquan Group is one of the important medium-to low-grade metamorphic units within the Wenquan metamorphic complexes which distributes in Chinese segment of the Tianshan Belt,the southern part of the Central Asian Orogenic Belt.It mainly consists of pre-Neoproterozoic metamorphosed volcanic and sedimentary rocks(Wang B et al.,2014).展开更多
This study examines the use of the geographic information systems (GIS) in structural geomorphology to build the model of the crust based on fractal analysis of relief. Fractal theory, developed by B. Mandelbrot, us...This study examines the use of the geographic information systems (GIS) in structural geomorphology to build the model of the crust based on fractal analysis of relief. Fractal theory, developed by B. Mandelbrot, used to determination morpho-bloc divisibility of the Earth's surface. There is the traceable statistically recurring relief structure indicate the appropriate tiered hierarchy of crustal blocks forming the tectonic and kinematic layers. This hypothesis tested on a digital elevation model (DEM) of the White Sea-Kuloi Plateau -- an area of tectonic and magmatic activity of the Paleozoic era. Found the correlation of position the kimberlite magmatic bodies with the tectonic blocks certain depth according to a flactal analysis.展开更多
In this paper, we report the assessment of the effect of the three-dimensional (3D) density heterogeneity in the mantle on Earth orientation parameters (EOP) (i.e., the polar motion, or PM, and the length of day,...In this paper, we report the assessment of the effect of the three-dimensional (3D) density heterogeneity in the mantle on Earth orientation parameters (EOP) (i.e., the polar motion, or PM, and the length of day, or LOD) in the tidal frequencies. The 3D mantle density model is estimated based upon a global S-wave velocity tomography model (S16U6LS) and the mineralogical knowledge derived from laboratory experiment. The lateral density variation is referenced against the preliminary reference earth model (PREM). Using this approach the effects of the heterogeneous manHe density variation in all three tidal frequencies (zonal long periods, tesseral diurnal, and sectorial semidiurnal) are estimated in both PM and LOD. When compared with mass or density perturbations originated on the Earth's surface such as the oceanic and barometric changes, the het- erogeneous mantle contributes less than 10% of the total variation in PM and LOD in tidal frequencies. However, this is the gap that has not been explained to close the gap of the observation and modeling in PM and LOD. By computing the PM and LOD caused by 3D heterogeneity of the mantle during the period of continuous space geodetic measure- ment campaigns (e.g., CONT94) and the contribution from ocean tides as predicted by tide models derived from satellite altimetry observations (e.g., TOPEX/Poseidon} in the same period, we got the lump-sum values of PM and LOD. The computed total effects and the observed PM and LOD are generally agree with each other. In another word, the difference of the observed PM and LOD and the model only considering ocean tides, at all tidal frequencies (long periods, diurnals, and semidiurnals) contains the contributions of the lateral density heterogeneity of the mantle. Study of the effect of mantle densityheterogeneity effect on torque-free Earth rotation may provide useful constraints to construct the reference earth model (REM), which is the next major objective in global geophysics research beyond PREM.展开更多
In South-Eastern forests of France,risks linked to the effects of tropospheric ozone(O_(3))are real;its annual impact has been observed specifically near the coastline and in high altitude mountains during the period ...In South-Eastern forests of France,risks linked to the effects of tropospheric ozone(O_(3))are real;its annual impact has been observed specifically near the coastline and in high altitude mountains during the period 2017-2019.In this study,the risk assessment of O_(3)pollutant was carried out using two approaches based on forest response indicators such as O_(3)specific foliar visible injury and by stomatal O_(3)flux.Phytotoxic O_(3)dose values(POD_(0))were obtained by the DO_(3)SE model.The model requires hourly O_(3)concentration for POD_(0)calculation.A modified approach that uses measurements from passive samplers(monthly average O_(3)concentration)was tested for the calculation of POD_(0)and test results showed good agreement with the POD_(0)calculated using hourly O_(3)data.In the model input file,the average O_(3)concentration is used for POD_(0),and this could be useful for POD_(0)calculation when the active monitor is limited.In this study,a flux-based assessment provided better correlation with O_(3)specific leaf injury,which is also species-specific.Foliar visible injury in response to O_(3)indicates that Pinus cembra and Pinus halepensis are more affected and therefore more sensitive than Pinus sylvestris.The POD_(0)and stomatal conductance(Gsto)seem to be induced by environmental factors,primarily rainfall and the soil water potential(fSWP).The correlation between the O_(3)flux metric and environmental variables with forest response indicators by Spearman rank test confirms P.cembra as one of the most sensitive species to O_(3).展开更多
Individual hydrocarbons identified to be macrocyclic alkanes in a torbanite from the Sydney Basin(Australia)were successfully isolated from its extracts using preparative gas chromatography and analyzed by NMR.Saturat...Individual hydrocarbons identified to be macrocyclic alkanes in a torbanite from the Sydney Basin(Australia)were successfully isolated from its extracts using preparative gas chromatography and analyzed by NMR.Saturated cyclic structures were confirmed by single peaks in the NMR~1H and~(13)C spectra indicating single forms of H and C atoms exist in these biomarker molecules.This is consistent with the methylene unit in a ring system assignment of the macrocyclic alkanes and accounts for a formula of(CH2)n.The unusual molecular structures of these compounds are consistent with those that were identified from previous GC retention index data and co-injection with a standard supports the previous research.The mass spectral fragmentation behaviors of representative cyclic alkanes were further investigated by comparing them with the mass spectra of isolated individual macrocyclic alkanes.The characteristic fragment ions in the macrocyclic alkanes of(M–28)+and base peaks of m/z 97,111,125,etc.,can be assigned as being generated by simple a-/i-cleavage and hydrogen rearrangement.These fragmentation pathways combined with retention indices should assist in differentiating these compounds from monounsaturated alkenes and alkylated monocyclics having similar mass spectral characteristics in other geological samples.展开更多
Our study focused on the valuation of Tchiky clays. This work aims to evaluate its properties to explore possible uses in pharmacy. Physico-chemical and mineralogical characterizations were carried out, as well as pha...Our study focused on the valuation of Tchiky clays. This work aims to evaluate its properties to explore possible uses in pharmacy. Physico-chemical and mineralogical characterizations were carried out, as well as pharmacopoeial tests and an evaluation of the antioxidant activity. Thus, chemical analysis by X-ray fluorescence spectrometry gave silicon (55.65%), iron (15.73%), aluminum (13.53%), potassium (6.05%), titanium (3.98%), magnesium (2.10%), and calcium (0.82%). X-ray diffraction showed the presence of kaolinite, quartz and illite. This study also revealed that the sample studied was essentially a plastic clay of hard consistency, with average flowability. The evaluation of the antioxidant activity gave a percentage inhibition of 62.97% for a concentration of 7.5 g/l with an IC50 of 5.5 g/l. These results should allow use as an excipient in pharmacy, particularly in liquid, semi-liquid and pasty formulations.展开更多
Based on petrological studies of the wall rocks, mineralizing rocks, ores and veins from the Laowangzhai gold deposit, it is discovered that along with the development of silication, carbonation and sulfidation, a kin...Based on petrological studies of the wall rocks, mineralizing rocks, ores and veins from the Laowangzhai gold deposit, it is discovered that along with the development of silication, carbonation and sulfidation, a kind of black opaque ultra-microlite material runs through the spaces between grains, fissures and cleavages. Under observations of the electron microprobe, scanning electronic microscopy and energy spectrum, this kind of ultra-microlite material is confirmed to consist of ultra microcrystalline quartz, silicate, sulfides and carbonates, as well as rutile, scheelite and specularite (magnetite), showing characters of liquation by the analyses of SEM and energy spectrum. The coexistence of immiscibility and precipitating co-crystallization strongly suggests that the mineralizing fluid changed from the melt to the hydrothermal fluid. Combined with the element geochemical researches, it is realized that the ultra-microlite aggregate is the direct relics of the mantle fluid behaving like a melt and supercritical fluid, which goes along with the mantle-derived magma and will escape from the magma body at a proper time. During the alteration process, the nature of the mantle fluid changed and it is mixed with the crustal fluid, which are favorable for mineralization in the Loawangzhai gold deposit.展开更多
文摘The objective of this study is to seek solutions to reduce the impact of buildings on climate change and to promote the use of local bio-sourced or geo-sourced materials for sustainable construction. Different samples of raw earth from 3 sites were taken in the commune of Mlomp. Geotechnical tests showed that the raw earth samples from sites 2 and 3 have more clay fraction while site 1 contains more sand. The fact of integrating fibers from crushed palm leaves (Borassus aethiopum) (2%, 4% and 6%) into the 3 raw earth samples reduced the mechanical resistance to compression and traction of the 3 raw earths. The experimental results of thermal tests on samples of earth mixtures with crushed Palma leaf fibers show a decrease in thermal conductivity as well as thermal effusivity as the percentages increase (2%, 4% and 6%) of fibers in raw earth for the 3 sites. This shows that this renewable composite material can help improve the thermal insulation of building envelopes.
基金supported by the National Natural Science Foundation of China(Grant Nos.41888101,41890834,91755213)the Most Special Fund(MSFGPMR02-3)from the State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences,Wuhana contribution to the IUGS International Lithosphere Program(2023-TF1)“Formation,Character,History and Behavior of Earth’s Oldest Lithospheres”。
文摘Geological maps encode vast amounts of data about rock types,ages,chemistry,orogenic architecture and deep-time history or different tectonic units,yet these are often difficult to extract because of the way different geologists portray their results at various scales.To understand orogenesis in 4D,it is essential to uniformly integrate map data,together with geophysical data and deep geochemical mapping(Wang et al.,2023).
基金supported by the National Natural Science Foundation of China (Grant No.42090023)the Alliance of International Science Organization (ANSO)Scholarship for Young Talents+3 种基金the Key Deployment Program of Chinese Academy of Sciences (YJKYYQ20190043,ZDBS-LY-DQC003,KFZD-SW-422,ZDRW-ZS-2021-3-1)the Scientific Research and Technology Development Project of China National Petroleum Corpo ration (2022DJ5503)the CAS Key Technology Talent ProgramSupercomputing Laboratory,IGGCAS。
文摘In-situ conversion presents a promising technique for exploiting continental oil shale formations,characterized by highly fractured organic-rich rock.A 3D in-situ conversion model,which incorporates a discrete fracture network,is developed using a self-developed thermal-flow-chemical(TFC)simulator.Analysis of the model elucidates the in-situ conversion process in three stages and defines the transformation of fluids into three distinct outcomes according to their end stages.The findings indicate that kerogen decomposition increases fluid pressure,activating fractures and subsequently enhancing permeability.A comprehensive analysis of activated fracture permeability and heating power reveals four distinct production modes,highlighting that increasing heating power correlates with higher cumulative fluid production.Activated fractures,with heightened permeability,facilitate the mobility of heavy oil toward production wells but hinder its cracking,thereby limiting light hydrocarbon production.Additionally,energy efficiency research demonstrates the feasibility of the in-situ conversion in terms of energy utilization,especially when considering the surplus energy from high-fluctuation energy sources such as wind and solar power to provide heating.
基金supported by the National Natural Science Foundation of China(No.51874280)the Fundamental Research Funds for the Central Universities(No.2021ZDPY0211)+2 种基金the Graduate Innovation Program of China University of Mining and Technology(No.2023WLKXJ046)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX23_2811)the Project of Liaoning Provincial Department of Education(No.JYTMS20231458).
文摘The infrared radiation temperature(IRT)variation concerning stress and crack evolution of rocks is a critical focus in rock mechanics domain and engineering disaster warning.In this paper,a methodology to extract the key IRT features related to stress and crack evolution of loaded rocks is proposed.Specifically,the wavelet denoising and reconstruction in thermal image sequence(WDRTIS)method is employed to eliminate temporal noise in thermal image sequences.Subsequently,the adaptive partition temperature drift correction(APTDC)method is introduced to alleviate temperature drift.On this basis,the spatial noise correction method based on threshold segmentation and adaptive median filtering(OTSU-AMF)is proposed to extract the key IRT features associated with microcracks of loaded rocks.Following temperature drift correction,IRT provides an estimation of the thermoelastic factor in rocks,typically around 5.29×10^(-5) MPa^(-1) for sandstones.Results reveal that the high-temperature concentrated region in cumulative thermal images of crack evolution(TICE)can elucidate the spatiotemporal evolution of localized damage.Additionally,heat dissipation of crack evolution(HDCE)acquired from TICE quantifies the progressive failure process of rocks.The proposed methodology enhances the reliability of IRT monitoring results and provides an innovative approach for conducting research in rock mechanics and monitoring engineering disasters.
文摘The use of gold as a tracer element for understanding the mode of emplacement of these formations requires a good knowledge of its dynamics. To this end, we have carried out experimental studies to investigate the evolution of contour states (regular, irregular), surface states (blunt, rough), shape (elongation) and dimension (size). The study of these criteria is carried out on SEM photos of particles, taken before and after the experiment, using Aphelion image processing software. Five experiments were carried out to study the influence of sediment granulometry and water dilution on particle morphological changes. The results of these experiments show that coarse sediments (>1 mm) are largely responsible for morphological changes in gold. They cause fragmentation and/or folding of the particle edges, depending on the magnitude of the impact forces. Strong impacts due to high water dilution cause staking on the particle surface. Fine sediments (<1 mm) slow down particle evolution as they cushion impacts and particles tend to flatten rather than fragment.
文摘Standards and specifications are the premise of integrated reorganization of science specimen data, and data integration is the core of the reorganization. ETL [1] which is the abbreviation of extract, transform, and load [2], is very suitable for data integration. Kettle is a kind of ETL software. In this paper, it has been introduced into the integrated reorganization of science specimen data. Multi-source and heterogeneous specimen data are integrated using kettle, and good results have been achieved. It proved the effectiveness of kettle in the integrated reorganization of science specimen data. The application has practical significance, and the method can be referenced when reorganizing other resource data.
基金sponsored by Academia Sinica and the National Science Council(under Grant No.NSC101-2119-M-001-01)
文摘The correlation of the scaled energy,e = Es/ Mo, versus earthquake magnitude, Ms, is studied based on two models: (1) Model 1 based on the use of the time function of the average displacements, with a ω^-2 source spectrum, across a fault plane; and (2) Model 2 based on the use of the time function of the average displacements, with a ω^-3 source spectrum, across a fault plane. For the second model, there are two cases: (a) As ζ= T, where r is the rise time and T the rupture time, lg(e) - -Ms; and (b) As ζ 〈〈 T, lg(e)- -(1/2)Ms. The second model leads to a negative value of e. This means that Model 2 cannot work for studying the present problem. The results obtained from Model 1 suggest that the source model is a factor, yet not a unique one, in controlling the correlation of e versus Ms.
基金supported by the National Natural Science Foundation of China(Grant No. 41474086 and 41704080)the Basic Research Project of Institute of Earthquake Forecasting of China Earthquake Administration (Grant No. 2018IES0402)supported by Academia Sinica
文摘Based on eight published plate motion models, we separately estimated the net area changes of tectonic plates and the area change of the solid Earth surface over geological time using the Euler vectors of plates with determined boundaries. Then, under the context of a currently expanding Earth, we inferred the change rate of the Earth’s mean radius from the estimated net area changes. The results show that the total increases and decreases in the areas of different plates cannot be compensated. Specifically, the area of the Northern Hemisphere decreases while that of the Southern Hemisphere increases, but the net area of the solid Earth surface slightly increases in th computing period(0.01 Ma). For the latest NNRMORVEL56 plate motion model, the area of the Southern Hemisphere increases by 7802 km2 while the area of the Northern Hemisphere decreases by 7711 km^2. This indicates a net area increase of 91 km2 in the solid Earth surface corresponding to an expansion rate of 0.06 mm/a for the Earths mean radius.This result coincides with the slow rate of expansion derived from geodetic measurements and geophysical modeling.
基金supported by NASA Earth Surface and Interior (ESI) Program (W.K.and J.C.)NASA Geomagnetic Infrastructure Fund+4 种基金NASA GSFC SEEC Fund (W.K.)NASA GRACE Project (J.C.)Taiwan Ministry of Science and Technology via grant 106-2116-M-001-013(B. F. Chao)NASA GSFC fellowship programIES of Academia Sinica for support of visiting tenure
文摘The observed Earth’s polar motion on decadal time scales has long been conjectured to be excited by the exchange of equatorial angular momentum between the solid mantle and the fluid outer core,via the mechanism of electromagnetic(EM)core-mantle coupling.However,past estimations of the EM coupling torque from surface geomagnetic observations is too weak to account for the observed decadal polar motion.Our recent estimations from numerical geodynamo simulations have shown the opposite.In this paper,we re-examine in detail the EM coupling mechanism and the properties of the magnetic field in the electrically conducting lower mantle(characterized by a thin D '-layer at the base of the mantle).Our simulations find that the toroidal field in the D'-layer from the induction and convection of the toroidal field in the outer core could be potentially much stronger than that from the advection of the poloidal field in the outer core.The former,however,cannot be inferred from geomagnetic observations at the Earth’s surface,and is missing in previous EM torque estimated from geomagnetic observations.Our deduction suggests further that this field could make the actual EM coupling torque sufficiently strong,at approximately 5×1019 Nm,to excite,and hence explain,the decadal polar motion to magnitude of approximately 10 mas.
基金Sponsored by the Taiwan Water Corporation under the Seismic Evaluation of JenYiTan Dam project,Academia Sinica (Taipei) and the National Sciences Council under Grant (NSC94-2119-M-001-016)
文摘Variations in acceleration and excess pore water pressure during a seismic event are critical early-warning indicators of an impending dam collapse.To assess these variations,the seismic responses for three simplified model dams,based on cross-sections through a real earthen dam,were assessed with numerical simulations and centrifuge tests.A normalized root-mean-square error was utilized as a comparison index to assess the closeness between simulated and the recorded values.Assuming that the experimental records are reliable,the reliability of the numerical program was evaluated using this root-mean-square error estimation approach.Explanations for inconsistency between the two approaches are presented.The conclusions are drawn from the results of the three model dams.
基金supported by the National Natural Science Foundation of China(41802093)the National Key R&D Program of China(2017YFC0601201 and 2018YFC0604002)+2 种基金the Project of Xinjiang Bureau of Geology and Mineral Resources(2011BAB06B03-3)the Project of China Geology Survey(DD20190405 and DD20190406)the Fundamental Research Funds for the Central Universities,Sun Yat-sen University(2021qntd23)。
文摘1.Objective The Wenquan Group is one of the important medium-to low-grade metamorphic units within the Wenquan metamorphic complexes which distributes in Chinese segment of the Tianshan Belt,the southern part of the Central Asian Orogenic Belt.It mainly consists of pre-Neoproterozoic metamorphosed volcanic and sedimentary rocks(Wang B et al.,2014).
文摘This study examines the use of the geographic information systems (GIS) in structural geomorphology to build the model of the crust based on fractal analysis of relief. Fractal theory, developed by B. Mandelbrot, used to determination morpho-bloc divisibility of the Earth's surface. There is the traceable statistically recurring relief structure indicate the appropriate tiered hierarchy of crustal blocks forming the tectonic and kinematic layers. This hypothesis tested on a digital elevation model (DEM) of the White Sea-Kuloi Plateau -- an area of tectonic and magmatic activity of the Paleozoic era. Found the correlation of position the kimberlite magmatic bodies with the tectonic blocks certain depth according to a flactal analysis.
基金supported by the NASA/ASEE Summer Faculty Fellowship while he visited the Branch of Space Geodesy,Goddard Space Flight Center to initiate this studythe support from the National Natural Science Foundation of China through grants No.41331066 and No.41474059partially supported by the CAS/CAFEA international partnership program for creative research teams (KZZD-EW-TZ-19)
文摘In this paper, we report the assessment of the effect of the three-dimensional (3D) density heterogeneity in the mantle on Earth orientation parameters (EOP) (i.e., the polar motion, or PM, and the length of day, or LOD) in the tidal frequencies. The 3D mantle density model is estimated based upon a global S-wave velocity tomography model (S16U6LS) and the mineralogical knowledge derived from laboratory experiment. The lateral density variation is referenced against the preliminary reference earth model (PREM). Using this approach the effects of the heterogeneous manHe density variation in all three tidal frequencies (zonal long periods, tesseral diurnal, and sectorial semidiurnal) are estimated in both PM and LOD. When compared with mass or density perturbations originated on the Earth's surface such as the oceanic and barometric changes, the het- erogeneous mantle contributes less than 10% of the total variation in PM and LOD in tidal frequencies. However, this is the gap that has not been explained to close the gap of the observation and modeling in PM and LOD. By computing the PM and LOD caused by 3D heterogeneity of the mantle during the period of continuous space geodetic measure- ment campaigns (e.g., CONT94) and the contribution from ocean tides as predicted by tide models derived from satellite altimetry observations (e.g., TOPEX/Poseidon} in the same period, we got the lump-sum values of PM and LOD. The computed total effects and the observed PM and LOD are generally agree with each other. In another word, the difference of the observed PM and LOD and the model only considering ocean tides, at all tidal frequencies (long periods, diurnals, and semidiurnals) contains the contributions of the lateral density heterogeneity of the mantle. Study of the effect of mantle densityheterogeneity effect on torque-free Earth rotation may provide useful constraints to construct the reference earth model (REM), which is the next major objective in global geophysics research beyond PREM.
基金funded by the Alcotra program MITIMPACT(Grand No.1671/1450109240)the Scientific Grant Agency of the Slovak Republic,VEGA(Project No.2/0093/2)。
文摘In South-Eastern forests of France,risks linked to the effects of tropospheric ozone(O_(3))are real;its annual impact has been observed specifically near the coastline and in high altitude mountains during the period 2017-2019.In this study,the risk assessment of O_(3)pollutant was carried out using two approaches based on forest response indicators such as O_(3)specific foliar visible injury and by stomatal O_(3)flux.Phytotoxic O_(3)dose values(POD_(0))were obtained by the DO_(3)SE model.The model requires hourly O_(3)concentration for POD_(0)calculation.A modified approach that uses measurements from passive samplers(monthly average O_(3)concentration)was tested for the calculation of POD_(0)and test results showed good agreement with the POD_(0)calculated using hourly O_(3)data.In the model input file,the average O_(3)concentration is used for POD_(0),and this could be useful for POD_(0)calculation when the active monitor is limited.In this study,a flux-based assessment provided better correlation with O_(3)specific leaf injury,which is also species-specific.Foliar visible injury in response to O_(3)indicates that Pinus cembra and Pinus halepensis are more affected and therefore more sensitive than Pinus sylvestris.The POD_(0)and stomatal conductance(Gsto)seem to be induced by environmental factors,primarily rainfall and the soil water potential(fSWP).The correlation between the O_(3)flux metric and environmental variables with forest response indicators by Spearman rank test confirms P.cembra as one of the most sensitive species to O_(3).
基金the financial support from The Strategic Priority Research Program of the Chinese Academy of Sciences(XDA14010102)Chinese National Science Foundation grants(4197306941673045)。
文摘Individual hydrocarbons identified to be macrocyclic alkanes in a torbanite from the Sydney Basin(Australia)were successfully isolated from its extracts using preparative gas chromatography and analyzed by NMR.Saturated cyclic structures were confirmed by single peaks in the NMR~1H and~(13)C spectra indicating single forms of H and C atoms exist in these biomarker molecules.This is consistent with the methylene unit in a ring system assignment of the macrocyclic alkanes and accounts for a formula of(CH2)n.The unusual molecular structures of these compounds are consistent with those that were identified from previous GC retention index data and co-injection with a standard supports the previous research.The mass spectral fragmentation behaviors of representative cyclic alkanes were further investigated by comparing them with the mass spectra of isolated individual macrocyclic alkanes.The characteristic fragment ions in the macrocyclic alkanes of(M–28)+and base peaks of m/z 97,111,125,etc.,can be assigned as being generated by simple a-/i-cleavage and hydrogen rearrangement.These fragmentation pathways combined with retention indices should assist in differentiating these compounds from monounsaturated alkenes and alkylated monocyclics having similar mass spectral characteristics in other geological samples.
文摘Our study focused on the valuation of Tchiky clays. This work aims to evaluate its properties to explore possible uses in pharmacy. Physico-chemical and mineralogical characterizations were carried out, as well as pharmacopoeial tests and an evaluation of the antioxidant activity. Thus, chemical analysis by X-ray fluorescence spectrometry gave silicon (55.65%), iron (15.73%), aluminum (13.53%), potassium (6.05%), titanium (3.98%), magnesium (2.10%), and calcium (0.82%). X-ray diffraction showed the presence of kaolinite, quartz and illite. This study also revealed that the sample studied was essentially a plastic clay of hard consistency, with average flowability. The evaluation of the antioxidant activity gave a percentage inhibition of 62.97% for a concentration of 7.5 g/l with an IC50 of 5.5 g/l. These results should allow use as an excipient in pharmacy, particularly in liquid, semi-liquid and pasty formulations.
基金supported by the National Natural Science Foundation of China (Grants No. 40473027 and 40773031)the Foundation of Doctoral Supported by the Ministry of Education (20105122110010 and 20115122110005)+1 种基金the Foundation of Open Subjects of State Key Laboratory for Mineral Deposits Research,Nanjing University (14-08-3)the Project of the State Key(Preparation Support) Disciplines of Mineralogy,Petrology and Mineral Deposit Geology of Sichuan Province (SZD0407)
文摘Based on petrological studies of the wall rocks, mineralizing rocks, ores and veins from the Laowangzhai gold deposit, it is discovered that along with the development of silication, carbonation and sulfidation, a kind of black opaque ultra-microlite material runs through the spaces between grains, fissures and cleavages. Under observations of the electron microprobe, scanning electronic microscopy and energy spectrum, this kind of ultra-microlite material is confirmed to consist of ultra microcrystalline quartz, silicate, sulfides and carbonates, as well as rutile, scheelite and specularite (magnetite), showing characters of liquation by the analyses of SEM and energy spectrum. The coexistence of immiscibility and precipitating co-crystallization strongly suggests that the mineralizing fluid changed from the melt to the hydrothermal fluid. Combined with the element geochemical researches, it is realized that the ultra-microlite aggregate is the direct relics of the mantle fluid behaving like a melt and supercritical fluid, which goes along with the mantle-derived magma and will escape from the magma body at a proper time. During the alteration process, the nature of the mantle fluid changed and it is mixed with the crustal fluid, which are favorable for mineralization in the Loawangzhai gold deposit.