Liquid marbles (non-stick droplets) containing crude petroleum are reported. Liquid marbles were ob- tained by use of fluorinated decyl polyhedral oligomeric silsequioxane (FD-POSS) powder. Marbles containing crud...Liquid marbles (non-stick droplets) containing crude petroleum are reported. Liquid marbles were ob- tained by use of fluorinated decyl polyhedral oligomeric silsequioxane (FD-POSS) powder. Marbles containing crude petroleum remained stable on a broad diversity of solid and liquid supports. The effective surface tension of marbles filled with petroleum was established. The mechanism of friction of the marbles is discussed. Actuation of liquid marbles containing crude petroleum with an electric field is presented.展开更多
Ruby-bearing marbles of the Southern Ural Mountains are developed in the metamorphic perimeter of granites-gneisses domes where high grade metamorphic granitization and diaphthoresis have occurred.Geological research ...Ruby-bearing marbles of the Southern Ural Mountains are developed in the metamorphic perimeter of granites-gneisses domes where high grade metamorphic granitization and diaphthoresis have occurred.Geological research into the development and occurrence of ruby-bearing marbles indicate that they formed as a result of repeated transformation.Their substrate consisted of an organogenous marine limestone containing Visean faunal remains.Intensive Mg metasomatism of limestone during early progressive stages of metamorphism resulted in a substrate of dolomite composition containing faunal remains with a calcite composition.Increased temperature and pressure resulted in metamorphism of early Mg metasomatites,turning them into fine-grained marble containing Visean faunal remains.Tensional stresses near the intrusive domes resulted in dedolomitization of early Mg metasomatites,giving rise to light,coarse-grained calcite marbles having polygonal-grained structure.Such carbonaceous marbles became metamorphosed around the perimeter of granite-gneiss massifs.Their rheological properties allowed for plastic flow in these marbles into areas of tectonic neutrality,forming bodies of rheomorphic marbles,sometimes even among marbled limestone.Relict bodies of Mg metasomatites underwent boudinage and rotation.Flow cleavage occurred in axial blocks of inter-dome structures and in their steep walls.Therefore platy jointing(banding,pseudo-lamination)formed in the marbles.Thickness of the plates is from several millimeters to 2-3m.Calcite underwent recrystallization with extension of grain size in the central parts of plates,sometimes amounting to 15-25cm in cross-section.Ruby-bearing marbles consist of Mg-calcite.The rock is coarse-grained,with a panidiomorphic texture.Schistosity is often observed in the plane of cleavage.Mg-calcite marble occurs among and grades into background calcite marbles,which are controlled by cleavage of flowing.It is supposed that the ruby-bearing Mg-calcite marbles bodies are elongated in the direction of dip.Their formation is caused by recrystallization under the action of rising metamorphogenic fluids at high temperatures and higher pressures(amphibolitic and epidote-amphibolitic facies).Ruby-bearing marbles formed at the end of the prograde stage of metamorphism.The early retrograde stage of metamorphism is defined by a new wave of Mg metasomatism and formation of calcite-dolomitic marbles with a poikiloblastic texture from calcite or Mg-calcite marbles.Usually the boundaries of the bodies are clear,planar,and controlled by cleavage.Studies of small bodies have shown that they are elongated in the direction of dip.Usually they contain pink corundum and/or pink spinel;red corundum is replaced by red spinel.Thus the initial marine limestones were transformed into various marbles and completely lost their primary composition and bedding as a result of metamorphism,deformation,and metasomatic transformation.Ruby-spinel mineralization in marbles is controlled by cleavage.展开更多
Eclogite lenses in marbles from the Dabie-Sulu ultrahigh-pressure (UHP) terrane are deeply subducted meta-sedimentary rocks. Zircons in these rocks have been used to constrain the ages of prograde and UHP metamorphi...Eclogite lenses in marbles from the Dabie-Sulu ultrahigh-pressure (UHP) terrane are deeply subducted meta-sedimentary rocks. Zircons in these rocks have been used to constrain the ages of prograde and UHP metamorphism during subduction, and later retrograde metamorphism during exhumation. Inherited (detrital) and metamorphic zircons were distinguished on the basis of transmitted light microscopy, cathodoluminescence (CL) imaging, trace element contents and mineral inclusions. The distribution of mineral inclusions combined with CL imaging of the metamorphic zircon make it possible to relate zircon zones (domains) to different metamorphic stages. Domain 1 consists of rounded, oblong and spindly cores with dark-luminescent images, and contains quartz eclogite facies mineral inclusion assemblages, indicating formation under high-pressure (HP) metamorphic conditions of T = 571-668℃ and P =1.7-2.02 GPa. Domain 2 always surrounds domain 1 or occurs as rounded and spindly cores with white-luminescent images. It contains coesite eclogite facies mineral inclusion assemblages, indicating formation under UHP metamorphic conditions of T = 782-849℃ and P 〉 5.5 GPa. Domain 3, with gray-luminescent images, always surrounds domain 2 and occurs as the outermost zircon rim. It is characterized by low-pressure mineral inclusion assemblages, which are related to regional amphibolite facies retrograde metamorphism of T = 600- 710℃ and P = 0.7-1.2 GPa. The three metamorphic zircon domains have distinct ages; sample H1 from the Dabie terrane yielded SHRIMP ages of 245 ± 4 Ma for domain 1, 235 ± 3 Ma for domain 2 and 215± 6 Ma for domain 3, whereas sample H2 from the Sulu terrane yielded similar ages of 244 ± 4 Ma, 233 ± 4 Ma and 214 ± 5 Ma for Domains 1, 2 and 3, respectively. The mean ages of these zones suggest that subduction to UHP depths took place over 10-11 Ma and exhumation of the rocks occurred over a period of 19-20 Ma. Thus, subduction from - 55 km to 〉 160 km deep mantle depth took place at rates of approximately 9.5-10.5 km/Ma and exhumation from depths 〉160 km to the base of the crust at -30 km occurred at approximately 6.5 km/Ma. We propose a model for these rocks involving deep subduction of continental margin lithosphere followed by ultrafast exhumation driven by buoyancy forces after break-off of the UHP slab deep within the mantle.展开更多
Determining the contents of F,S(total),and Cl in the studied samples of the limestone and marbles with high calcite contents was carried out by the nondestructive method of WDXRFS(Wavelength Dispersive X-ray Fluoresce...Determining the contents of F,S(total),and Cl in the studied samples of the limestone and marbles with high calcite contents was carried out by the nondestructive method of WDXRFS(Wavelength Dispersive X-ray Fluorescence Spectrometry).All measurements were performed in a vacuum condition using a WDXRF spectrometer S8 TIGER(Bruker AXS,Germany).The studied samples have wide ranges of F,S(total),and Cl contents,and high concentration of calcite(89.5%-99%).Main objective of this research is to develop WDXRF(WD X-ray fluorescence)technique for the determination of F,S(total),and Cl.The calculated values of the ILD(instrumental limit of the detection)were within the interval from 3 for S(total)to 37 for F mg/kg.The repeatability was found to be satisfactory with the relative standard deviations lower than 7%.展开更多
The radioactivity of 15 kinds of different granites collected in Tunisia was determined by gamma-ray spectrometry using hyper-pure germanium (HPGe) detector. The average activity concentrations for primordial radionuc...The radioactivity of 15 kinds of different granites collected in Tunisia was determined by gamma-ray spectrometry using hyper-pure germanium (HPGe) detector. The average activity concentrations for primordial radionuclides 238U, 232Th and 40K were respectively 33.24, 8.01 and 116.98 Bq/kg. The activity concentrations ranged from 3.59 to 87.37 Bq/kg for 238U, from 0.45 to 25.34 Bq/kg for 232Th and from 24.06 to 380.23 Bq/kg for 40K. The measured activity concentrations were used to assess of the radium equivalent activity ranged from 22.2 to 995.8 Bq/kg, the absorbed dose rate in air from 7 to 1209 nGy/h and the internal (0.1 to 2.8) and external (0.1 to 2.7) hazard indices. The data obtained in this study may be useful for natural radioactivity mapping.展开更多
Dilatancy is a fundamental volumetric growth behavior observed during loading and serves as a key index to comprehending the intricate nonlinear behavior and constitutive equation structure of rock.This study focuses ...Dilatancy is a fundamental volumetric growth behavior observed during loading and serves as a key index to comprehending the intricate nonlinear behavior and constitutive equation structure of rock.This study focuses on Jinping marble obtained from the Jinping Underground Laboratory in China at a depth of 2400 m.Various uniaxial and triaxial tests at different strain rates,along with constant confining pressure tests and reduced confining pressure tests under different confining pressures were conducted to analyze the mechanical response and dilatancy characteristics of the marble under four stress paths.Subsequently,a new empirical dilatancy coefficient is proposed based on the energy dissipation method.The results show that brittle failure characteristics of marble under uniaxial compression are more obvious with the strain rate increasing,and plastic failure characteristics of marble under triaxial compression are gradually strengthened.Furthermore,compared to the constant confining pressure,the volume expansion is relatively lower under unloading condition.The energy dissipation is closely linked to the process of dilatancy,with a rapid increase of dissipated energy coinciding with the beginning of dilatancy.A new empirical dilatancy coefficient is defined according to the change trend of energy dissipation rate curve,of which change trend is consistent with the actual dilatancy response in marble under different stress paths.The existing empirical and theoretical dilatancy models are analyzed,which shows that the empirical dilatancy coefficient based on the energy background is more universal.展开更多
It was during the Great Depression(2) in a small village. Food and money were still in very short supply and trading goods for other goods was very common.Mr. Miller sold some fresh produce on the roadside. I used to ...It was during the Great Depression(2) in a small village. Food and money were still in very short supply and trading goods for other goods was very common.Mr. Miller sold some fresh produce on the roadside. I used to trade things with him.One day when I paid for my potatoes.展开更多
Investigations on the oxygen and carbon isotope compositions from the ultrahigh-pressure (UHP)-metamorphosed Shuanghe marbles, that occur as a member of a UHP slab, show that the δ18 O values range from +11.1% to+20....Investigations on the oxygen and carbon isotope compositions from the ultrahigh-pressure (UHP)-metamorphosed Shuanghe marbles, that occur as a member of a UHP slab, show that the δ18 O values range from +11.1% to+20.5% SMOW, and δ13 C from+1.0% to+5.7% PDB, respectively. The variations in isotope compositions show a centimeter scale of homogeneity and a heterogeneity of regional scale larger than 1 meter.In contrast to the eclogite marbles from Norway, the Shuanghe marbles have inherited the carbon isotope compositions from their sedimentary precursor. The δ13C shows positive correlation to the content of dolomite. The depletion in18O, compared with the pmtolithic carbonate strata, might result from three possible geological processes: 1) exchanging oxygen isotope with meteoric water before the UHP metamorphism, 2) decarbonation during the UHP metamorphism, and 3) exchanging oxygen isotope with country gneiss at local scale during retrograde metamorphism.It seems that the advection of fluid in the orogenic belt was very limited during subduction and exhumation of UHP rocks.展开更多
Bubbles and foams are ubiquitous in daily life and industrial processes.Studying their dynamic behaviors is of key importance for foam manufacturing processes in food packaging,cosmetics and pharmaceuticals.Bare bubbl...Bubbles and foams are ubiquitous in daily life and industrial processes.Studying their dynamic behaviors is of key importance for foam manufacturing processes in food packaging,cosmetics and pharmaceuticals.Bare bubbles are inherently fragile and transient;enhancing their robustness and shelf lives is an ongoing challenge.Their rupture can be attributed to liquid evaporation,thin film drainage and the nuclei of environmental dust.Inspired by particle-stabilized interfaces in Pickering emulsions,armored bubbles and liquid marble,bubbles are protected by an enclosed particle-entrapping liquid thin film,and the resultant soft object is termed gas marble.The gas marble exhibits mechanical strength orders of magnitude higher than that of soap bubbles when subjected to overpressure and underpressure,owing to the compact particle monolayer straddling the surface liquid film.By using a water-absorbent glycerol solution,the resulting gas marble can persist for 465 d in normal atmospheric settings.This particle-stabilizing approach not only has practical implications for foam manufacturing processes but also can inspire the new design and fabrication of functional biomaterials and biomedicines.展开更多
Cellulose microspheres were fabricated on the basis of sol-gel transition using NaOH/urea/H_(2)O as the solvent system.These microspheres had an average diameter of about 30μm.Upon modification with Fe_(3)O_(4) and p...Cellulose microspheres were fabricated on the basis of sol-gel transition using NaOH/urea/H_(2)O as the solvent system.These microspheres had an average diameter of about 30μm.Upon modification with Fe_(3)O_(4) and poly(DOPAm-co-PFOEA),superhydrophobic magnetic cellulose microspheres were generated,which were analyzed by FTIR,TG,XRD,XPS and water contact angle tests.Magnetic cellulose microspheres contained approximately 15 wt%of Fe_(3)O_(4).Poly(DOPAm-co-PFOEA)/Fe_(3)O_(4)/cellulose microspheres and had a low surface energy and a high water-repellency.These superhydrophobic microspheres were also converted into liquid marbles via an easily scalable process.展开更多
This is a report of carbon isotope anomaly in marbles associated with the UHP eclogites from the Dabie Mountains. The results place constraints on the degree of crust_mantle interaction during the UHP metamorphism.
Over the past few decades,genetic selection and refined nutritional management have extensively been used to increase the growth rate and lean meat production of livestock.However,the rapid growth rates of modern bree...Over the past few decades,genetic selection and refined nutritional management have extensively been used to increase the growth rate and lean meat production of livestock.However,the rapid growth rates of modern breeds are often accompanied by a reduction in intramuscular fat deposition and increased occurrences of muscle abnor‑malities,impairing meat quality and processing functionality.Early stages of animal development set the long‑term growth trajectory of offspring.However,due to the seasonal reproductive cycles of ruminant livestock,gestational nutrient deficiencies caused by seasonal variations,frequent droughts,and unfavorable geological locations nega‑tively affect fetal development and their subsequent production efficiency and meat quality.Therefore,enrolling live‑stock in nutritional intervention strategies during gestation is effective for improving the body composition and meat quality of the offspring at harvest.These crucial early developmental stages include embryonic,fetal,and postnatal stages,which have stage‑specific effects on subsequent offspring development,body composition,and meat quality.This review summarizes contemporary research in the embryonic,fetal,and neonatal development,and the impacts of maternal nutrition on the early development and programming effects on the long‑term growth performance of livestock.Understanding the developmental and metabolic characteristics of skeletal muscle,adipose,and fibrotic tissues will facilitate the development of stage‑specific nutritional management strategies to optimize production efficiency and meat quality.展开更多
Marble is widely used in construction industry mainly in interior & exterior design of buildings due to its resilient physical, chemical & mechanical properties. The diverse geology of Gilgit Baltistan has nat...Marble is widely used in construction industry mainly in interior & exterior design of buildings due to its resilient physical, chemical & mechanical properties. The diverse geology of Gilgit Baltistan has naturally endowed this region with different varieties of marble deposits. These marble deposits need proper characterization to ensure their proper use in the construction industry. This research aims to conduct a preliminary study for the characterization of the Nasir Abad Hunza marble deposit. Samples from said deposit were subjected to different tests to study its chemical, physical and mechanical properties. Results of XRF analysis reveal that the deposit under study is dolomitic. The comparison of different physical properties of deposits with standard values confirms its originality. However, high variation in the strength of core samples was observed, which could result from incomplete crystallization by metamorphism. This variation in the strength of samples suggests strength-based definitions of deposit domains to propose the use of each domain separately.展开更多
Marble is a metamorphic rock, which is one of the 3 basic rock types (magmatic, sedimentary, metamorphic) forming the earth’s crust. The major characteristic sought after in a rock mass in the field for it to be expo...Marble is a metamorphic rock, which is one of the 3 basic rock types (magmatic, sedimentary, metamorphic) forming the earth’s crust. The major characteristic sought after in a rock mass in the field for it to be exportable and usable as marble is its suitability to be cut in blocks. In the process of producing marble slabs from marble blocks, the blocks are expected not to contain potentially problematic hard or weak zones and their geomechanical and chemical properties should conform to the relevant standards. Ignoring of the geological properties of the rock in the process of deciding for marble production at a marble site and determination of production location, direction and method is the most important parameter that would increase production loss. In order to reduce losses by determination of geological properties of marble, many academic studies have been conducted on the effects of water saturation, temperature, freezing and thawing on its mechanical and fracture properties. There are further studies on crack propagation in marble under stress. However, even those marble blocks that are obtained based on geological parameters may suffer serious cracks or fractures due to stresses caused by their weight and geometry. Therefore, cutting direction is of critical importance in order to minimize marble waste in the process of cutting a marble block which is brought to the inventory or processing site with cracks, cavities or fractures. Certain studies exist within such context, where the geometry of the discontinuity within a block is determined using non-destructive methods, such as ultrasonic testing, in order to determine the appropriate cutting direction. Such studies made use of ultrasonic waves to determine the physical and chemical structures of magmatic and sedimentary rocks by measuring the progress velocity of sonic waves in the rock. Said studies, however, mostly worked on sedimentary and magmatic rock specimens, focusing less on metamorphic rocks such as marble due to their anisotropic properties. Understanding the academic literature studies on marble would provide significant contribution to the reduction of production losses during the processing marble blocks in processing plants and the achievement of production efficiency levels that are within economic limits. Within such scope, this study has reviewed the past academic studies on marble, classified them under 6 categories, and comprehensively analyzed each category based on materials, testing setups, test specimens, test parameters and research techniques.展开更多
Strainburst is one type of rockburst that generally occurs in deep tunnel.In this study,the strainburst behaviors of marble specimens were investigated under tunnel-excavation-induced stress condition,and two stress p...Strainburst is one type of rockburst that generally occurs in deep tunnel.In this study,the strainburst behaviors of marble specimens were investigated under tunnel-excavation-induced stress condition,and two stress paths were designed,a commonly used stress path in true triaxial unloading rockburst tests and a new test path in which the intermediate principal stress was varied.During the tests,a high-speed camera was used to record the strainburst process,and an acoustic emission(AE)monitoring system was used to monitor the AE characteristics of failure.In these two stress paths,all the marble specimens exhibited strainbursts;however,when the intermediate principal stress was varied,the rockburst became more violent.The obtained results indicate that the intermediate principal stress has a significant effect on rockburst behavior of marble.Under a higher intermediate principal stress before the unloading,more elastic strain energy was accumulated in the specimen,and the cumulative AE energy was higher in the rockburst-induced failure,i.e.,more elastic strain energy was released during the failure.Therefore,more violent failure was observed:more rock fragments with a higher mass and larger size were ejected outward.展开更多
基金made to the Donors of the American Chemical Society Petroleum Research Fund for support of this research(Grant 52043-UR5)
文摘Liquid marbles (non-stick droplets) containing crude petroleum are reported. Liquid marbles were ob- tained by use of fluorinated decyl polyhedral oligomeric silsequioxane (FD-POSS) powder. Marbles containing crude petroleum remained stable on a broad diversity of solid and liquid supports. The effective surface tension of marbles filled with petroleum was established. The mechanism of friction of the marbles is discussed. Actuation of liquid marbles containing crude petroleum with an electric field is presented.
文摘Ruby-bearing marbles of the Southern Ural Mountains are developed in the metamorphic perimeter of granites-gneisses domes where high grade metamorphic granitization and diaphthoresis have occurred.Geological research into the development and occurrence of ruby-bearing marbles indicate that they formed as a result of repeated transformation.Their substrate consisted of an organogenous marine limestone containing Visean faunal remains.Intensive Mg metasomatism of limestone during early progressive stages of metamorphism resulted in a substrate of dolomite composition containing faunal remains with a calcite composition.Increased temperature and pressure resulted in metamorphism of early Mg metasomatites,turning them into fine-grained marble containing Visean faunal remains.Tensional stresses near the intrusive domes resulted in dedolomitization of early Mg metasomatites,giving rise to light,coarse-grained calcite marbles having polygonal-grained structure.Such carbonaceous marbles became metamorphosed around the perimeter of granite-gneiss massifs.Their rheological properties allowed for plastic flow in these marbles into areas of tectonic neutrality,forming bodies of rheomorphic marbles,sometimes even among marbled limestone.Relict bodies of Mg metasomatites underwent boudinage and rotation.Flow cleavage occurred in axial blocks of inter-dome structures and in their steep walls.Therefore platy jointing(banding,pseudo-lamination)formed in the marbles.Thickness of the plates is from several millimeters to 2-3m.Calcite underwent recrystallization with extension of grain size in the central parts of plates,sometimes amounting to 15-25cm in cross-section.Ruby-bearing marbles consist of Mg-calcite.The rock is coarse-grained,with a panidiomorphic texture.Schistosity is often observed in the plane of cleavage.Mg-calcite marble occurs among and grades into background calcite marbles,which are controlled by cleavage of flowing.It is supposed that the ruby-bearing Mg-calcite marbles bodies are elongated in the direction of dip.Their formation is caused by recrystallization under the action of rising metamorphogenic fluids at high temperatures and higher pressures(amphibolitic and epidote-amphibolitic facies).Ruby-bearing marbles formed at the end of the prograde stage of metamorphism.The early retrograde stage of metamorphism is defined by a new wave of Mg metasomatism and formation of calcite-dolomitic marbles with a poikiloblastic texture from calcite or Mg-calcite marbles.Usually the boundaries of the bodies are clear,planar,and controlled by cleavage.Studies of small bodies have shown that they are elongated in the direction of dip.Usually they contain pink corundum and/or pink spinel;red corundum is replaced by red spinel.Thus the initial marine limestones were transformed into various marbles and completely lost their primary composition and bedding as a result of metamorphism,deformation,and metasomatic transformation.Ruby-spinel mineralization in marbles is controlled by cleavage.
基金the National 973 Project of Chinese Ministry of Science and Technology (Grant No. 2003CB716502) the Natural Science Foundation of China (Grant No. 40399143) +1 种基金 the German Science Foundation (DFG grant No. GE 1152/2-2 , WE2850/3- 1).
文摘Eclogite lenses in marbles from the Dabie-Sulu ultrahigh-pressure (UHP) terrane are deeply subducted meta-sedimentary rocks. Zircons in these rocks have been used to constrain the ages of prograde and UHP metamorphism during subduction, and later retrograde metamorphism during exhumation. Inherited (detrital) and metamorphic zircons were distinguished on the basis of transmitted light microscopy, cathodoluminescence (CL) imaging, trace element contents and mineral inclusions. The distribution of mineral inclusions combined with CL imaging of the metamorphic zircon make it possible to relate zircon zones (domains) to different metamorphic stages. Domain 1 consists of rounded, oblong and spindly cores with dark-luminescent images, and contains quartz eclogite facies mineral inclusion assemblages, indicating formation under high-pressure (HP) metamorphic conditions of T = 571-668℃ and P =1.7-2.02 GPa. Domain 2 always surrounds domain 1 or occurs as rounded and spindly cores with white-luminescent images. It contains coesite eclogite facies mineral inclusion assemblages, indicating formation under UHP metamorphic conditions of T = 782-849℃ and P 〉 5.5 GPa. Domain 3, with gray-luminescent images, always surrounds domain 2 and occurs as the outermost zircon rim. It is characterized by low-pressure mineral inclusion assemblages, which are related to regional amphibolite facies retrograde metamorphism of T = 600- 710℃ and P = 0.7-1.2 GPa. The three metamorphic zircon domains have distinct ages; sample H1 from the Dabie terrane yielded SHRIMP ages of 245 ± 4 Ma for domain 1, 235 ± 3 Ma for domain 2 and 215± 6 Ma for domain 3, whereas sample H2 from the Sulu terrane yielded similar ages of 244 ± 4 Ma, 233 ± 4 Ma and 214 ± 5 Ma for Domains 1, 2 and 3, respectively. The mean ages of these zones suggest that subduction to UHP depths took place over 10-11 Ma and exhumation of the rocks occurred over a period of 19-20 Ma. Thus, subduction from - 55 km to 〉 160 km deep mantle depth took place at rates of approximately 9.5-10.5 km/Ma and exhumation from depths 〉160 km to the base of the crust at -30 km occurred at approximately 6.5 km/Ma. We propose a model for these rocks involving deep subduction of continental margin lithosphere followed by ultrafast exhumation driven by buoyancy forces after break-off of the UHP slab deep within the mantle.
文摘Determining the contents of F,S(total),and Cl in the studied samples of the limestone and marbles with high calcite contents was carried out by the nondestructive method of WDXRFS(Wavelength Dispersive X-ray Fluorescence Spectrometry).All measurements were performed in a vacuum condition using a WDXRF spectrometer S8 TIGER(Bruker AXS,Germany).The studied samples have wide ranges of F,S(total),and Cl contents,and high concentration of calcite(89.5%-99%).Main objective of this research is to develop WDXRF(WD X-ray fluorescence)technique for the determination of F,S(total),and Cl.The calculated values of the ILD(instrumental limit of the detection)were within the interval from 3 for S(total)to 37 for F mg/kg.The repeatability was found to be satisfactory with the relative standard deviations lower than 7%.
文摘The radioactivity of 15 kinds of different granites collected in Tunisia was determined by gamma-ray spectrometry using hyper-pure germanium (HPGe) detector. The average activity concentrations for primordial radionuclides 238U, 232Th and 40K were respectively 33.24, 8.01 and 116.98 Bq/kg. The activity concentrations ranged from 3.59 to 87.37 Bq/kg for 238U, from 0.45 to 25.34 Bq/kg for 232Th and from 24.06 to 380.23 Bq/kg for 40K. The measured activity concentrations were used to assess of the radium equivalent activity ranged from 22.2 to 995.8 Bq/kg, the absorbed dose rate in air from 7 to 1209 nGy/h and the internal (0.1 to 2.8) and external (0.1 to 2.7) hazard indices. The data obtained in this study may be useful for natural radioactivity mapping.
基金Project(2022NSFSC0279)supported by the General Project of Sichuan Natural Science Foundation,ChinaProject(Z17113)supported by the Key Scientific Research Fund of Xihua University,ChinaProject(SR21A04)supported by the Research Center for Social Development and Social Risk Control of Sichuan Province,Key Research Base of Philosophy and Social Sciences,Sichuan University,China。
文摘Dilatancy is a fundamental volumetric growth behavior observed during loading and serves as a key index to comprehending the intricate nonlinear behavior and constitutive equation structure of rock.This study focuses on Jinping marble obtained from the Jinping Underground Laboratory in China at a depth of 2400 m.Various uniaxial and triaxial tests at different strain rates,along with constant confining pressure tests and reduced confining pressure tests under different confining pressures were conducted to analyze the mechanical response and dilatancy characteristics of the marble under four stress paths.Subsequently,a new empirical dilatancy coefficient is proposed based on the energy dissipation method.The results show that brittle failure characteristics of marble under uniaxial compression are more obvious with the strain rate increasing,and plastic failure characteristics of marble under triaxial compression are gradually strengthened.Furthermore,compared to the constant confining pressure,the volume expansion is relatively lower under unloading condition.The energy dissipation is closely linked to the process of dilatancy,with a rapid increase of dissipated energy coinciding with the beginning of dilatancy.A new empirical dilatancy coefficient is defined according to the change trend of energy dissipation rate curve,of which change trend is consistent with the actual dilatancy response in marble under different stress paths.The existing empirical and theoretical dilatancy models are analyzed,which shows that the empirical dilatancy coefficient based on the energy background is more universal.
文摘It was during the Great Depression(2) in a small village. Food and money were still in very short supply and trading goods for other goods was very common.Mr. Miller sold some fresh produce on the roadside. I used to trade things with him.One day when I paid for my potatoes.
基金Project supported by a U. S.-China cooperative project led by ProfCong Bolin of the Institute of Geology, Chinese Academy of Sciences+1 种基金Prof. J. G. Liou of the Department of Geological and Environmental SciencesStanford University by the Nationa
文摘Investigations on the oxygen and carbon isotope compositions from the ultrahigh-pressure (UHP)-metamorphosed Shuanghe marbles, that occur as a member of a UHP slab, show that the δ18 O values range from +11.1% to+20.5% SMOW, and δ13 C from+1.0% to+5.7% PDB, respectively. The variations in isotope compositions show a centimeter scale of homogeneity and a heterogeneity of regional scale larger than 1 meter.In contrast to the eclogite marbles from Norway, the Shuanghe marbles have inherited the carbon isotope compositions from their sedimentary precursor. The δ13C shows positive correlation to the content of dolomite. The depletion in18O, compared with the pmtolithic carbonate strata, might result from three possible geological processes: 1) exchanging oxygen isotope with meteoric water before the UHP metamorphism, 2) decarbonation during the UHP metamorphism, and 3) exchanging oxygen isotope with country gneiss at local scale during retrograde metamorphism.It seems that the advection of fluid in the orogenic belt was very limited during subduction and exhumation of UHP rocks.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.22078197 and 52172283)the Natural Science Foundation of Guangdong Province(Grant No.2021A1515012506).
文摘Bubbles and foams are ubiquitous in daily life and industrial processes.Studying their dynamic behaviors is of key importance for foam manufacturing processes in food packaging,cosmetics and pharmaceuticals.Bare bubbles are inherently fragile and transient;enhancing their robustness and shelf lives is an ongoing challenge.Their rupture can be attributed to liquid evaporation,thin film drainage and the nuclei of environmental dust.Inspired by particle-stabilized interfaces in Pickering emulsions,armored bubbles and liquid marble,bubbles are protected by an enclosed particle-entrapping liquid thin film,and the resultant soft object is termed gas marble.The gas marble exhibits mechanical strength orders of magnitude higher than that of soap bubbles when subjected to overpressure and underpressure,owing to the compact particle monolayer straddling the surface liquid film.By using a water-absorbent glycerol solution,the resulting gas marble can persist for 465 d in normal atmospheric settings.This particle-stabilizing approach not only has practical implications for foam manufacturing processes but also can inspire the new design and fabrication of functional biomaterials and biomedicines.
文摘Cellulose microspheres were fabricated on the basis of sol-gel transition using NaOH/urea/H_(2)O as the solvent system.These microspheres had an average diameter of about 30μm.Upon modification with Fe_(3)O_(4) and poly(DOPAm-co-PFOEA),superhydrophobic magnetic cellulose microspheres were generated,which were analyzed by FTIR,TG,XRD,XPS and water contact angle tests.Magnetic cellulose microspheres contained approximately 15 wt%of Fe_(3)O_(4).Poly(DOPAm-co-PFOEA)/Fe_(3)O_(4)/cellulose microspheres and had a low surface energy and a high water-repellency.These superhydrophobic microspheres were also converted into liquid marbles via an easily scalable process.
文摘This is a report of carbon isotope anomaly in marbles associated with the UHP eclogites from the Dabie Mountains. The results place constraints on the degree of crust_mantle interaction during the UHP metamorphism.
基金supported by the Agriculture and Food Research Initiative Competitive Grants(No.2015-67015-23219 and 2016-68006-24634)from the USDA National Institute of Food and Agriculture.
文摘Over the past few decades,genetic selection and refined nutritional management have extensively been used to increase the growth rate and lean meat production of livestock.However,the rapid growth rates of modern breeds are often accompanied by a reduction in intramuscular fat deposition and increased occurrences of muscle abnor‑malities,impairing meat quality and processing functionality.Early stages of animal development set the long‑term growth trajectory of offspring.However,due to the seasonal reproductive cycles of ruminant livestock,gestational nutrient deficiencies caused by seasonal variations,frequent droughts,and unfavorable geological locations nega‑tively affect fetal development and their subsequent production efficiency and meat quality.Therefore,enrolling live‑stock in nutritional intervention strategies during gestation is effective for improving the body composition and meat quality of the offspring at harvest.These crucial early developmental stages include embryonic,fetal,and postnatal stages,which have stage‑specific effects on subsequent offspring development,body composition,and meat quality.This review summarizes contemporary research in the embryonic,fetal,and neonatal development,and the impacts of maternal nutrition on the early development and programming effects on the long‑term growth performance of livestock.Understanding the developmental and metabolic characteristics of skeletal muscle,adipose,and fibrotic tissues will facilitate the development of stage‑specific nutritional management strategies to optimize production efficiency and meat quality.
文摘Marble is widely used in construction industry mainly in interior & exterior design of buildings due to its resilient physical, chemical & mechanical properties. The diverse geology of Gilgit Baltistan has naturally endowed this region with different varieties of marble deposits. These marble deposits need proper characterization to ensure their proper use in the construction industry. This research aims to conduct a preliminary study for the characterization of the Nasir Abad Hunza marble deposit. Samples from said deposit were subjected to different tests to study its chemical, physical and mechanical properties. Results of XRF analysis reveal that the deposit under study is dolomitic. The comparison of different physical properties of deposits with standard values confirms its originality. However, high variation in the strength of core samples was observed, which could result from incomplete crystallization by metamorphism. This variation in the strength of samples suggests strength-based definitions of deposit domains to propose the use of each domain separately.
文摘Marble is a metamorphic rock, which is one of the 3 basic rock types (magmatic, sedimentary, metamorphic) forming the earth’s crust. The major characteristic sought after in a rock mass in the field for it to be exportable and usable as marble is its suitability to be cut in blocks. In the process of producing marble slabs from marble blocks, the blocks are expected not to contain potentially problematic hard or weak zones and their geomechanical and chemical properties should conform to the relevant standards. Ignoring of the geological properties of the rock in the process of deciding for marble production at a marble site and determination of production location, direction and method is the most important parameter that would increase production loss. In order to reduce losses by determination of geological properties of marble, many academic studies have been conducted on the effects of water saturation, temperature, freezing and thawing on its mechanical and fracture properties. There are further studies on crack propagation in marble under stress. However, even those marble blocks that are obtained based on geological parameters may suffer serious cracks or fractures due to stresses caused by their weight and geometry. Therefore, cutting direction is of critical importance in order to minimize marble waste in the process of cutting a marble block which is brought to the inventory or processing site with cracks, cavities or fractures. Certain studies exist within such context, where the geometry of the discontinuity within a block is determined using non-destructive methods, such as ultrasonic testing, in order to determine the appropriate cutting direction. Such studies made use of ultrasonic waves to determine the physical and chemical structures of magmatic and sedimentary rocks by measuring the progress velocity of sonic waves in the rock. Said studies, however, mostly worked on sedimentary and magmatic rock specimens, focusing less on metamorphic rocks such as marble due to their anisotropic properties. Understanding the academic literature studies on marble would provide significant contribution to the reduction of production losses during the processing marble blocks in processing plants and the achievement of production efficiency levels that are within economic limits. Within such scope, this study has reviewed the past academic studies on marble, classified them under 6 categories, and comprehensively analyzed each category based on materials, testing setups, test specimens, test parameters and research techniques.
基金Project(2016YFC0801403) supported by the National Key Research and Development Program of ChinaProject(2017RCJJ012) supported by the Scientific Research Foundation of Shandong University of Science and Technology for Recruited Talents,China+1 种基金Project(ZR2018MEE009) supported by the Shandong Provincial Natural Science Foundation,ChinaProject(MDPC2017ZR04) supported by the Open Project Fund for State Key Laboratory of Mining Disaster Prevention and Control Co-founded by Shandong Province and the Ministry of Science and Technology of China
文摘Strainburst is one type of rockburst that generally occurs in deep tunnel.In this study,the strainburst behaviors of marble specimens were investigated under tunnel-excavation-induced stress condition,and two stress paths were designed,a commonly used stress path in true triaxial unloading rockburst tests and a new test path in which the intermediate principal stress was varied.During the tests,a high-speed camera was used to record the strainburst process,and an acoustic emission(AE)monitoring system was used to monitor the AE characteristics of failure.In these two stress paths,all the marble specimens exhibited strainbursts;however,when the intermediate principal stress was varied,the rockburst became more violent.The obtained results indicate that the intermediate principal stress has a significant effect on rockburst behavior of marble.Under a higher intermediate principal stress before the unloading,more elastic strain energy was accumulated in the specimen,and the cumulative AE energy was higher in the rockburst-induced failure,i.e.,more elastic strain energy was released during the failure.Therefore,more violent failure was observed:more rock fragments with a higher mass and larger size were ejected outward.