In this study we measured the △P(initial speed of gas emission) index with different gas concentrations of carbon dioxide(pure CO2,90% CO2+10% CH4,67% CO2+33% CH4,50% CO2+50% CH4,30% CO2+10% CH4 and pure CH4) of coal...In this study we measured the △P(initial speed of gas emission) index with different gas concentrations of carbon dioxide(pure CO2,90% CO2+10% CH4,67% CO2+33% CH4,50% CO2+50% CH4,30% CO2+10% CH4 and pure CH4) of coal samples from the No.2 coal seam in the Yaojie Coal Mine,Gansu province,China.The effect of carbon dioxide concentration,gas composition,coal strength and particle size of coal samples on the △P index was investigated.The experimental results show that with gas of various compositions,the △P value of three samples were clearly different.The △P index of coal samples A,B and C(0.2～0.25 mm) were 4,6 and 7 with pure CH4 and 22,30 and 21 when pure CH4 was used.Carbon dioxide concentration affects the △P index markedly.The △P index increases with an increase in carbon dioxide concentration,especially for coal B.Hence,the △P index and K(another outburst index) values tested only with pure CH4 for prediction of the danger of outburst is not accurate.It is important to determine the initial speed of gas emission given the gas composition of the coal seam to be tested for exact outburst prediction.展开更多
Portable X-ray fluorescence(pXRF) spectrometers can be used to determine the elemental composition easily, rapidly, and without using chemical reagents, which is very important for tropical regions due to the lack of ...Portable X-ray fluorescence(pXRF) spectrometers can be used to determine the elemental composition easily, rapidly, and without using chemical reagents, which is very important for tropical regions due to the lack of detailed soil characterization data. Moreover,pXRF data can be used to predict the results of more expensive, time-consuming, and conventional laboratory analyses. This study sought to determine the elemental composition of various soil profiles using pXRF. Two operational modes(Trace Mode and General Mode) and two scanning time(30 and 60 s) were assessed to determine their effects on the correlation of pXRF dataset with respect to conventional inductively coupled plasma(ICP)-optical emission spectrometry analysis. This relationship has been reported in previous studies, however, few studies were performed on tropical soils, which are unique. Furthermore, such relationships establish the viability of developing prediction models directly from pXRF data. Linear regression was applied to develop calibration models for the prediction of ICP analysis results and exchangeable and available elemental contents based on pXRF data. High coefficients of determination(R^2) were obtained for Ca(0.87), Cu(0.90), Fe(0.95), Mn(0.85), Cr(0.95), V(0.72), and Ni(0.90), with adequate validation. Statistically significant results were not found for Al, K, Zn, Ti, and Zr. The models predicting the exchangeable Ca based on the total Ca from p XRF reached an R^2 of up to 0.85. Operational modes influenced the pXRF results. Our results illustrate that pXRF holds great promise for tropical soil characterization and the development of prediction models, justifying the need for larger-scale studies in tropical countries worldwide.展开更多
Since its first literature mention in conjunction with cast iron in 1931 by Esser and Lautenbusch,thermal analysis(TA)has journeyed a long way.Today it is an accepted and widely used tool for process control for all t...Since its first literature mention in conjunction with cast iron in 1931 by Esser and Lautenbusch,thermal analysis(TA)has journeyed a long way.Today it is an accepted and widely used tool for process control for all types of cast irons.This paper reviews the latest progress in the development of equipment and analysis methods that make TA successful in applications such as the estimation of chemical composition,graphitization potential,and the shape and number of graphite aggregates.The potential and limitations of the prediction of shrinkage defects propensity are analyzed in some details.Examples of attempts at prediction of mechanical properties and shrinkage propensity are also discussed.Several graphs showing the data scattering are presented to convey the reader a better sense of the accuracy of various predictions.展开更多
Web services run in a highly dynamic environment, as a result, the QoS of which will change relatively frequently. In order to make the composite service adapt to such dynamic property of Web services, we propose a se...Web services run in a highly dynamic environment, as a result, the QoS of which will change relatively frequently. In order to make the composite service adapt to such dynamic property of Web services, we propose a self-healing approach for web service composition. Such an approach is an integration of backing up in selection and reselecting in execution. In order to make the composite service heal itself as quickly as possible and minimize the number of reselections, a way of performance prediction is proposed in this paper. On this basis, the self-healing approach is presented including framework, the triggering algorithm of the reselection and the reliability model of the service. Experiments show that the proposed solutions have better performance in supporting the self-healing Web service composition.展开更多
Ancient glass relics are easily weathered by the influence of buried environment, and the internal elements exchange with the environmental elements in large quantities, resulting in changes in their composition ratio...Ancient glass relics are easily weathered by the influence of buried environment, and the internal elements exchange with the environmental elements in large quantities, resulting in changes in their composition ratio. Archaeological research can often detect the component content of glass relics after weathering, but it is difficult to obtain the corresponding component content before weathering. It is necessary to predict the chemical composition of glass relics before weathering in order to accurately identify the type of glass relics and repair them. To solve this problem, this paper proposes a distributed matching strategy, and studies the influence of weathering on the composition content of glass through compositional correlation analysis and linear regression statistical methods, so as to build a prediction model of the composition content of glass relics before weathering. The results show that the composition prediction model of glass cultural relics constructed by the distribution matching strategy has a good prediction ability, which is consistent with the change trend of the composition ratio of linear regression analysis. Moreover, the model is simple and easy to operate, which is convenient for popularization and application, and provides theoretical basis and reference value for further research on the composition and accurate classification of glass cultural relics.展开更多
The ratio of P- to S-wave velocities （Vp/Vs） is regarded as one of the most diagnostic properties of natural rocks. It has been used as a discriminant of composition for the continental crust and provides valuable c...The ratio of P- to S-wave velocities （Vp/Vs） is regarded as one of the most diagnostic properties of natural rocks. It has been used as a discriminant of composition for the continental crust and provides valuable constraints on its formation and evolution processes. Furthermore, the spatial and temporal changes in Vp/Vs before and after earthquakes are probably the most promising avenue to understanding the source mechanics and possibly predicting earthquakes. Here we calibrate the variations in Vp/Vs in dry, anisotropic crustal rocks and provide a set of basic information for the interpretation of future seismic data from the Wenchuan earthquake Fault zone Scientific Drilling （WFSD） project and other surveys. Vp/Vs is a constant （Ф0） for an isotropic rock. However, most of crustal rocks are anisotropic due to lattice-preferred orientations of anisotropic minerals （e.g., mica, amphibole, plagioclase and pyroxene） and cracks as well as thin compositional layering. The Vp/Vs ratio of an anisotropic rock measured along a selected pair of propagation-vibration directions is an apparent value （Фy） that is significantly different from the value for its isotropic counterpart （Ф0）. The usefulness of apparent Vp/Vs ratios as a diagnostic of crustal composition depends largely on rock seismic anisotropy. A 5% of P- and S-wave velocity anisotropy is sufficient to make it impossible to determine the crustal composition using the conventional criteria （Vp/Vs≤1.756 for felsic rocks, 1.756〈Vp/Vs≤1.809 for intermediate rocks, 1.809〈Vp/Vs≤1.944 for mafic rocks, and Vp/V2〉1.944 fluidfilled porous/fractured or partially molten rocks） if the information about the wave propagation-polarization directions with respect to the tectonic framework is unknown. However, the variations in Vp/Vs measured from borehole seismic experiments can be readily interpreted according to the orientations of the ray path and the polarization of the shear waves with respect to the present-day principal stress di展开更多
The objective of this study was to determine the accuracy and reliability of 2 optical chlorophyll meters:FieldScout CM 1,000 NDVI and Yara N-Tester, in predicting neutral detergent fibre(NDF), acid detergent fibre(AD...The objective of this study was to determine the accuracy and reliability of 2 optical chlorophyll meters:FieldScout CM 1,000 NDVI and Yara N-Tester, in predicting neutral detergent fibre(NDF), acid detergent fibre(ADF), acid detergent lignin(ADL), acid detergent insoluble nitrogen(ADIN) and in vitro ruminal organic matter degradability(IVOMD) of 3 tropical grasses. Optical chlorophyll measurements were taken at 3 stages(4, 8 and 12 weeks) of regrowth in Brachiaria hybrid, and Megathyrsus maximus and at 6 and 12 weeks of regrowth in Paspalum atratum(cv. Ubon). Optical chlorophyll measurements showed the highest correlation(r = 0.57 to 0.85) with NDF concentration. The FieldScout CM 1,000 NDVI was better than the Yara N-Tester in predicting NDF(R^2 = 0.70) and ADF(R^2 = 0.79) concentrations in Brachiaria hybrid and NDF(R^2 = 0.79) in M. maximus. Similarly, FieldScout CM 1,000 NDVI produced better estimates of 24 h IVOMD(IVOMD_(24 h)) in Brachiaria hybrid(R^2 = 0.81) and IVOMD_(48 h) in Brachiaria hybrid(R^2 = 0.65) and M. maximus(R^2 = 0.75). However, these prediction models had relatively low concordance correlation coefficients, i.e., CCC >0.90, but random errors were the main source of bias. It was,therefore, concluded that both optical chlorophyll meters were poor and unreliable predictors of ADIN and ADL concentrations. Overall, the FieldScout CM 1,000 NDVI shows potential to produce useful estimates of IVOMD_(24h) and ADF in Brachiaria hybrid and IVOMD_(48 h) and NDF concentrations in M. maximus.展开更多
基金supported by the Key Project of the Natural Science Foundation of China (Nos.70533050 and 50774084)
文摘In this study we measured the △P(initial speed of gas emission) index with different gas concentrations of carbon dioxide(pure CO2,90% CO2+10% CH4,67% CO2+33% CH4,50% CO2+50% CH4,30% CO2+10% CH4 and pure CH4) of coal samples from the No.2 coal seam in the Yaojie Coal Mine,Gansu province,China.The effect of carbon dioxide concentration,gas composition,coal strength and particle size of coal samples on the △P index was investigated.The experimental results show that with gas of various compositions,the △P value of three samples were clearly different.The △P index of coal samples A,B and C(0.2～0.25 mm) were 4,6 and 7 with pure CH4 and 22,30 and 21 when pure CH4 was used.Carbon dioxide concentration affects the △P index markedly.The △P index increases with an increase in carbon dioxide concentration,especially for coal B.Hence,the △P index and K(another outburst index) values tested only with pure CH4 for prediction of the danger of outburst is not accurate.It is important to determine the initial speed of gas emission given the gas composition of the coal seam to be tested for exact outburst prediction.
基金the Brazilian funding agenciesNational Council for Scientific and Technological Development(CNPq)+1 种基金Coordination of Superior Level Staff Improvement(CAPES)Foundation for Research of the State of Minas Gerais(FAPEMIG)
文摘Portable X-ray fluorescence(pXRF) spectrometers can be used to determine the elemental composition easily, rapidly, and without using chemical reagents, which is very important for tropical regions due to the lack of detailed soil characterization data. Moreover,pXRF data can be used to predict the results of more expensive, time-consuming, and conventional laboratory analyses. This study sought to determine the elemental composition of various soil profiles using pXRF. Two operational modes(Trace Mode and General Mode) and two scanning time(30 and 60 s) were assessed to determine their effects on the correlation of pXRF dataset with respect to conventional inductively coupled plasma(ICP)-optical emission spectrometry analysis. This relationship has been reported in previous studies, however, few studies were performed on tropical soils, which are unique. Furthermore, such relationships establish the viability of developing prediction models directly from pXRF data. Linear regression was applied to develop calibration models for the prediction of ICP analysis results and exchangeable and available elemental contents based on pXRF data. High coefficients of determination(R^2) were obtained for Ca(0.87), Cu(0.90), Fe(0.95), Mn(0.85), Cr(0.95), V(0.72), and Ni(0.90), with adequate validation. Statistically significant results were not found for Al, K, Zn, Ti, and Zr. The models predicting the exchangeable Ca based on the total Ca from p XRF reached an R^2 of up to 0.85. Operational modes influenced the pXRF results. Our results illustrate that pXRF holds great promise for tropical soil characterization and the development of prediction models, justifying the need for larger-scale studies in tropical countries worldwide.
文摘Since its first literature mention in conjunction with cast iron in 1931 by Esser and Lautenbusch,thermal analysis(TA)has journeyed a long way.Today it is an accepted and widely used tool for process control for all types of cast irons.This paper reviews the latest progress in the development of equipment and analysis methods that make TA successful in applications such as the estimation of chemical composition,graphitization potential,and the shape and number of graphite aggregates.The potential and limitations of the prediction of shrinkage defects propensity are analyzed in some details.Examples of attempts at prediction of mechanical properties and shrinkage propensity are also discussed.Several graphs showing the data scattering are presented to convey the reader a better sense of the accuracy of various predictions.
基金supported by the National Natural Science Foundation of China under Grant No. 60773218
文摘Web services run in a highly dynamic environment, as a result, the QoS of which will change relatively frequently. In order to make the composite service adapt to such dynamic property of Web services, we propose a self-healing approach for web service composition. Such an approach is an integration of backing up in selection and reselecting in execution. In order to make the composite service heal itself as quickly as possible and minimize the number of reselections, a way of performance prediction is proposed in this paper. On this basis, the self-healing approach is presented including framework, the triggering algorithm of the reselection and the reliability model of the service. Experiments show that the proposed solutions have better performance in supporting the self-healing Web service composition.
文摘Ancient glass relics are easily weathered by the influence of buried environment, and the internal elements exchange with the environmental elements in large quantities, resulting in changes in their composition ratio. Archaeological research can often detect the component content of glass relics after weathering, but it is difficult to obtain the corresponding component content before weathering. It is necessary to predict the chemical composition of glass relics before weathering in order to accurately identify the type of glass relics and repair them. To solve this problem, this paper proposes a distributed matching strategy, and studies the influence of weathering on the composition content of glass through compositional correlation analysis and linear regression statistical methods, so as to build a prediction model of the composition content of glass relics before weathering. The results show that the composition prediction model of glass cultural relics constructed by the distribution matching strategy has a good prediction ability, which is consistent with the change trend of the composition ratio of linear regression analysis. Moreover, the model is simple and easy to operate, which is convenient for popularization and application, and provides theoretical basis and reference value for further research on the composition and accurate classification of glass cultural relics.
基金funded by the Natural Sciences and Engineering Council of Canada and the Geological Survey of China
文摘The ratio of P- to S-wave velocities （Vp/Vs） is regarded as one of the most diagnostic properties of natural rocks. It has been used as a discriminant of composition for the continental crust and provides valuable constraints on its formation and evolution processes. Furthermore, the spatial and temporal changes in Vp/Vs before and after earthquakes are probably the most promising avenue to understanding the source mechanics and possibly predicting earthquakes. Here we calibrate the variations in Vp/Vs in dry, anisotropic crustal rocks and provide a set of basic information for the interpretation of future seismic data from the Wenchuan earthquake Fault zone Scientific Drilling （WFSD） project and other surveys. Vp/Vs is a constant （Ф0） for an isotropic rock. However, most of crustal rocks are anisotropic due to lattice-preferred orientations of anisotropic minerals （e.g., mica, amphibole, plagioclase and pyroxene） and cracks as well as thin compositional layering. The Vp/Vs ratio of an anisotropic rock measured along a selected pair of propagation-vibration directions is an apparent value （Фy） that is significantly different from the value for its isotropic counterpart （Ф0）. The usefulness of apparent Vp/Vs ratios as a diagnostic of crustal composition depends largely on rock seismic anisotropy. A 5% of P- and S-wave velocity anisotropy is sufficient to make it impossible to determine the crustal composition using the conventional criteria （Vp/Vs≤1.756 for felsic rocks, 1.756〈Vp/Vs≤1.809 for intermediate rocks, 1.809〈Vp/Vs≤1.944 for mafic rocks, and Vp/V2〉1.944 fluidfilled porous/fractured or partially molten rocks） if the information about the wave propagation-polarization directions with respect to the tectonic framework is unknown. However, the variations in Vp/Vs measured from borehole seismic experiments can be readily interpreted according to the orientations of the ray path and the polarization of the shear waves with respect to the present-day principal stress di
基金the University of the West Indies and the Jamaica Dairy Development Board for providing financial support to undertake this research
文摘The objective of this study was to determine the accuracy and reliability of 2 optical chlorophyll meters:FieldScout CM 1,000 NDVI and Yara N-Tester, in predicting neutral detergent fibre(NDF), acid detergent fibre(ADF), acid detergent lignin(ADL), acid detergent insoluble nitrogen(ADIN) and in vitro ruminal organic matter degradability(IVOMD) of 3 tropical grasses. Optical chlorophyll measurements were taken at 3 stages(4, 8 and 12 weeks) of regrowth in Brachiaria hybrid, and Megathyrsus maximus and at 6 and 12 weeks of regrowth in Paspalum atratum(cv. Ubon). Optical chlorophyll measurements showed the highest correlation(r = 0.57 to 0.85) with NDF concentration. The FieldScout CM 1,000 NDVI was better than the Yara N-Tester in predicting NDF(R^2 = 0.70) and ADF(R^2 = 0.79) concentrations in Brachiaria hybrid and NDF(R^2 = 0.79) in M. maximus. Similarly, FieldScout CM 1,000 NDVI produced better estimates of 24 h IVOMD(IVOMD_(24 h)) in Brachiaria hybrid(R^2 = 0.81) and IVOMD_(48 h) in Brachiaria hybrid(R^2 = 0.65) and M. maximus(R^2 = 0.75). However, these prediction models had relatively low concordance correlation coefficients, i.e., CCC >0.90, but random errors were the main source of bias. It was,therefore, concluded that both optical chlorophyll meters were poor and unreliable predictors of ADIN and ADL concentrations. Overall, the FieldScout CM 1,000 NDVI shows potential to produce useful estimates of IVOMD_(24h) and ADF in Brachiaria hybrid and IVOMD_(48 h) and NDF concentrations in M. maximus.
