Search

Shengli Oilfield has abundant oil and gas resources， with multiple types of reservoirs， and logging evaluation plays an essential role in exploration and development. The development history and the characteristics of logging evaluation technologies for reservoirs were systematically reviewed to celebrate the institute's 60th birthday. Summarizing experience and predicting the future have positive significance for the development and application in the professional logging field. A series of mature evaluation technologies formed in three types of reservoirs， including conventional sandstone reservoirs， complex reservoirs， and unconventional shale reservoirs， were systematically summarized according to the characteristics and evaluation difficulties of reservoirs. For conventional sandstone reservoirs， a highly applicable identification technology for oil layers was systematically developed， and an innovative method for establishing electrical standards constrained by the lower limits of lithology and oil potential was developed under multi-layer joint testing conditions. In addition， a pioneering logging modeling technology was proposed based on different diagenetic zones. Various technologies were developed for complex reservoirs， including logging identification of sandstone lithology in steep slope zones， effectiveness evaluation of low-permeability sandstone reservoirs， and identification and evaluation of oil layers with low resistivity. For unconventional shale reservoirs， a logging evaluation technology of reservoir parameters was preliminarily developed to evaluate the storage properties and oil potential mainly based on two-dimensional nuclear magnetic resonance experiments. These logging evaluation technologies for different types of reservoirs reflected the combination of wellbore data and geological understanding， as well as the integration of rock physics and logging models， and they demonstrated the ability of logging to serve geology and reservoirs and achieved good application results. In the future， the remaining resources will mainly be distributed in hidden oil and gas reservoirs and deep layers. In order to meet the needs of exploration and development， it is necessary to strengthen the analysis of experimental data， gas logging， and testing production data， combine logging evaluation and geology， intensify the application of new logging technologies such as logging while drilling， imaging， and nuclear magnetic resonance， carry out comprehensive research and evaluation， and expand the evaluation and prediction of production capacity of oil layers from the perspective of evaluation objectives. Moreover， it is necessary to fully rely on expert experience to select samples and deepen the application of big data/artificial intelligence on the basis of conventional technologies， which will definitely achieve good results.

Discrete element simulation of triaxial compression test was carried out to study the effects of confining pressure and saturation on the macro and meso mechanical properties of gas hydrate bearing coal (GHBC). Firstly, the numerical models of three kinds of GHBC with different saturations were established by particle flow program PFC3D, with the cementation of hydrate simulated by parallel bonding model. Then, the meso mechanical parameters were calibrated by using the results of the physical triaxial test. The stress-strain curves of the physical tests agree with the simulated results, with the failure strength and strength parameter error rate within 10%, which verifies the reliability of the established numerical model. Furthermore, the triaxial tests of GHBC were performed under different confining pressures to analyze the macro and meso-mechanical characteristics such as the stress-strain curve, velocity field, contact force chain, coordination number and porosity. The results show that the discrete element simulation results agree well with the indoor test results, especially simulating the strain hardening characteristics of the sample. The velocity field reveals a higher dilatancy degree under low saturation and a higher contraction degree under the high confining pressure of the samples. There is no obvious difference in the main chain transfer direction at the failure strength under different saturations and confining pressures. The contact force, the number of contact force chains, as well as the coordination number increase with the increase of confining pressure and saturation, while the porosity tends to decrease, which enhances the strength of the samples. The friction is an important factor to maintain the stability of the meso mechanical system of the samples. The influence mechanism of saturation and confining pressure on the strength deformation and failure of GHBC is revealed from the microscale, which provides a theoretical reference for the discrete element simulation of GHBC triaxial test and for the prevention of coal and gas outburst by hydrate technology.

Copyright of Petroleum Geology & Recovery Efficiency is the property of Petroleum Geology & Recovery Efficiency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to study the influence of bimodal pore structure on the mechanical properties of unsaturated soil, two typical bimodal pore structure clays in Nanning and Guilin in Guangxi were selected as target materials and the shear strength characteristics under different saturation conditions were analyzed. The effect mechanism of pore water distribution status on the strength of two kinds of soils with bimodal pore structure was explored by filter paper method and nuclear magnetic resonance (NMR) technique. The results show that the T2 distribution curves of the two samples have bimodal structure under saturated condition. Moreover, on the whole, the water retention characteristics of soil samples show bimodal soil-water characteristic curve. The stress-displacement relationship of the two kinds of soil is similar and the shear strength is closely related to saturation. The change trend of soil sample cohesion changes when the saturation is 40%, while the internal friction angle reaches the minimum at a saturation of 80%. [ABSTRACT FROM AUTHOR]

The attitude tracking control problem of an overdriven quadrotor aircraft experimental platform is studied. The platform has unknown input disturbances and angular velocity cannot be measured, and the motor also has dead zone and saturation nonlinear characteristics. First, a linear perturbed double-integral model of the platform is established. Afterwards, an attitude-tracking robust controller including a proportional-integral-derivative nominal controller and an adaptive extended state observer (AESO) is designed. Among them, the nominal controller is used to ensure the asymptotic stability of the nominal closed-loop system, and AESO is used to estimate the angular velocity and disturbance information of the experimental platform to solve the problem of no velocity measurement and disturbance suppression. Moreover, the overdrive control allocation problem is solved by using the pseudo-inverse matrix method. In addition, an auxiliary system is constructed to weaken the influence of the motor’s dead zone and saturated nonlinear characteristics. Finally, the simulation and experiments verify that the proposed control strategy can effectively solve the problems caused by the dead zone and saturation characteristics of the motor, and can simultaneously take into account the transient overshoot and steady-state error performance of the closed-loop system.

Copyright of Aero Weaponry is the property of Aero Weaponry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Water content is one of the critical factors affecting frost damage to rock masses in alpine regions. A dynamic disturbance load further complicates the issue. In this study, the effects of saturation and impact loading on the dynamic behavior of the frozen red sandstone were investigated using a low-temperature split Hopkinson pressure bar (LT-SHPB) experimental system. By combining low-field nuclear magnetic resonance (NMR) and scanning electron microscopy (SEM), the dynamic evolution of the microstructure of the frozen sandstone due to changes in saturation was investigated. The experimental results show that the increase in saturation reshapes the pore structure of the frozen sandstone and promotes the expansion of pores of different sizes during freezing, while the frozen samples at complete saturation are mainly developed with mesopore and macropore. The dynamic strength, elastic modulus and brittleness index of the frozen sandstone under impact loading, which are limited by the critical saturation Src, tend to increase and then decrease with saturation increase. In contrast, the ultimate deformation capacity of the frozen sandstone showed an opposite trend with saturation. With increasing impact loading, the dynamic strength, elastic modulus, and peak strain of the frozen sandstone gradually increase, showing an obvious strain-rate enhancement effect; while the brittleness index decreases by 8.1% at full saturation when the impact velocity increases from 4 m/s to 6 m/s, indicating that the dynamic damage mode develops from brittle to ductile. Moreover, the frozen samples changed from tensile damage to composite damage with increasing saturation and impact loading; the distribution of crushing masses remained closely related to their dynamic strength. Based on the experimental results, the mechanism of the effects of saturation variation on the dynamic mechanical behavior of frozen sandstone is discussed.

The liquid channel characteristics of coalescing filter material directly affect the filtration performance of coalescing filter elements for natural gas purification. Herein, the channel saturation and pressure drop of two kinds of industrial oleophobic filter materials were tested by a filter material experimental device. Then, an investigation was conducted within the filtration gas velocity of 0.1-0.7 m/s and the dynamic liquid viscosity of 46-320 mPa·s to explore their comprehensive influence on the characteristics of liquid channel inside the coalescing filter material. The results show that the channel saturation and pressure drop inside the coalescing filter material decrease exponentially with the increase of the filtration gas velocity under the same dynamic liquid viscosity, and increase linearly with the increase of liquid viscosity under the same filtration gas velocity. Based on these rules, a prediction model of liquid channel characteristics was established, and the relevant results could be used to quantitatively characterize the interaction between liquid channel characteristics and the parameters, such as the filter material structure, liquid viscosity and filtration velocity.

In order to investigate the salt migration rule in one-dimensional saturated media under density-driven conditions, a density driven test of NaCl solution released from the top of soil column and a concentration dispersion test of NaCl solution released from the bottom of soil column were carried out respectively. Among them, the density driven test included two parts: the dynamic test of high concentration salt migration under density driven conditions and the salt migration characteristic test of different concentrations. The salt dispersion test included two parts: the dynamic process test of high concentration gradient dispersion and the dispersion characteristic test under different concentration gradients. The test device with a column made of perspex in a height of 115 cm and an inner diameter of 11 cm was established. The water inlet and outlet were respectively arranged at the bottom and top of the column, and the water isolation bottom plate was arranged at a position of 5 cm above the bottom. Holes were drilled every 10 cm from bottom to top on the side wall of the column and soil solution extractors were placed to extract soil solutions. The filling medium of the glass column was cleaned and air-dried quartz sand (0.5-1.0 mm). After filling, deionized water was used to saturate the soil column from bottom to top. The results showed that the effect of density-driven on salt migration was much greater than that of concentration dispersion during the test period. Driven by density, the salt released from the top quickly migrated downward, and the salt concentration in the upper layer was greater than that at the bottom within 5-120 min. After 330 min, the concentration increased with the increase of depth, and the salt gradually accumulated towards the bottom. The bottom concentration reached the maximum after 720 min. In addition, during the whole migration process, the peak of salt concentration moved downward with the increase of time, the peak value decreased from 54.3 g/L at the beginning of the experiment (after 5 min) to 24.2 g/L at the end of 21 600 min. However, the change of salt concentration by dispersion was slow, and only the concentration at the within 20 cm of the bottom of the soil column changed significantly within 30 days. The law of salt migration was different for different concentrations of salt solutions. The higher the concentration released from the top, the more obvious the density driving effect was, and the salt content in the depth range of 70-100 cm at the bottom of soil column was higher. After 15 days, the proportion of salt content at the bottom of 150, 100, 60, 40, 12 and 6 g/L decreased successively, and were 47.1%, 40.2%, 40.0%, 38.0%, 36.7% and 33.3%, respectively. The higher the concentration of salt released from the bottom, the greater the upward diffusion flux, but the effect on the redistribution of concentration was not obvious. After 15 days of testing, the salt released at concentrations of 100, 60, and 40 g/L was mainly distributed at depths of 80-100 cm, and the salt concentration at other depths was low, while the salt concentration at concentrations of 6 g/L gradually decreased with depth decreasing, which was similar to the distribution rule driven by positive density. The salt content at the within 20 cm of soil column of NaCl solution with concentrations of 100, 60, 40 and 6 g/L decreased successively, were 82.7%, 72.7%, 62.4% and 37.5%, respectively. Based on four sets of laboratory onedimensional saturated soil column tests, this study quantified the density driven salt migration rule and the dispersion dynamic rule under different concentration gradients of salt solutions, which can provide theoretical basis for salt balance research in arid irrigation area. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Engineering Geology / Gongcheng Dizhi Xuebao is the property of Journal of Engineering Geology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Petroleum Geology & Recovery Efficiency is the property of Petroleum Geology & Recovery Efficiency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The conventional triaxial loading tests were conducted under different saturation(50%, 80%) and confining pressures (12 MPa, 16 MPa, 20 MPa) to explore the applicability of Mohr-Coulomb(M-C) criterion, Hoek-Brown (H-B) criterion as well as Generalized Hoek-Brown(GH-B) criterion to gas hydrate-containing coal under high confining pressure condition. The stress-strain curves were analyzed, and the variation of the main principal stress with the confining pressure was fitted by using the formulas of three strength criteria. Meanwhile, the root mean square deviation RMSE and correlation coefficient were introduced to evaluate the applicability of different strength criteria for gas hydrate-containing coal. The results show that the stress-strain curves exhibit strain hardening characteristics under the condition of high confining pressure. The higher the confining pressure and saturation, the higher the peak strength. The confining pressure has a significant effect on the peak strength. M-C and GH-B criteria are proved to have good fitting effect on the test data, with higher correlation coefficient and lower RMSE value than H-B criterion. The linear fitting line between the predicted value and the test value is very close to the 1∶1 gradient line, indicating that the two criteria have good applicability to gas hydrate-containing coal. The correlation coefficient of H-B criterion is lower than M-C and GH-B criterion. The RMSE value is larger, and the applicability of H-B criterion to gas hydrate-containing coal is slightly lower than M-C criterion and GH-B criterion.

Since gas hydrate exists in three different forms at the same time such as pore filling, particle support and separate stratification, the calculation method of hydrate saturation using traditional shaly sand formation interpretation models is equivalent to considering only the simple case that hydrate exists as pore filling, and does not consider other complex states. Based on the analysis of hydrate resistivity experimental data and the general form of the resistivity-oil (gas) saturation relationship, the best simplified formula of hydrate saturation calculation is derived, then the physical meaning of the three items are clarified: they respectively represent the resistivity index-saturation relationship when hydrate particles are completely distributed in the pores of formation rocks, supported in the form of particles, and exist in layers, corresponding quantitative evaluation method of hydrate saturation is built. The field application shows that the hydrate saturation calculated by this method is closer to that obtained by sampling analysis. At the same time, it also provides a logging analysis basis for the effective development after hydrate exploration.

Water has an obvious degrading effect on the mechanical parameters of rock and soil.In this paper, triaxial tests of landslide deposits under different water content conditions were carried out, and empirical equations between saturation and mechanical parameters were established. Besides, secondary development on the established empirical equation was also carried out. Based the coupling of saturation and mechanical parameters, the influence of sliding body mechanical parameter changes on the landslide stability can then be considered in the process of real-time changes in reservoir water level.By comparing the simulation results of the Dahua landslide in Lanping County, Yunnan Province during the rise of the reservoir water level with the field monitoring data, the rationality of considering the water-induced deterioration effect of the mechanical parameters of the sliding body was verified.In the end, the engineering application of the deformation evolution law of the Dahua landslide considering water-induced deterioration was carried out.

To investigate the effect of freeze-thaw cycles on the moisture susceptibility of asphalt mixtures, the changes of adhesion work and exfoliated work between asphalt aggregate interface under different freeze-thaw cycles were analyzed based on the surface free energy theory, and the moisture stability of asphalt mixture was evaluated. The effects of water saturation and freeze-thaw on the water stability of asphalt mixture were further explored by splitting test and Logistic model. The results show that with the increasing of freeze-thaw times, the surface energy and cohesive work of asphalt are decreased with decreased adhesion work between asphalt and aggregate, while the exfoliated work is increased with decreased moisture susceptibility of asphalt mixture. The void fraction of asphalt mixture is increased with the increasing of freeze-thaw times, while the splitting strength is decreased. The greater the saturation of asphalt mixture during freeze-thaw is, the greater the damage degree and damage rate are. When the saturation of asphalt mixture is greater than 50.00%, the effect of freeze-thaw on the performance of asphalt mixture becomes more obvious. Therefore, it is recommended that the freeze-thaw splitting test of asphalt mixture should be carried out under the condition of saturation higher than 50.00%. [ABSTRACT FROM AUTHOR]

Copyright of Petroleum Geology & Oilfield Development in Daqing is the property of Editorial Department of Petroleum Geology & Oilfield Development in Daqing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The frequent fluctuation of gas flow during the storage and transportation can easily lead to the failure of filter cartridge and the shortening of its service life. Thus, an experimental device for the filtration performance of coalescence filter cartridge was established according to the relevant test standards. On this basis, the effects of apparent gas velocity and its dynamic change on the saturation of oleophobic coalescence filter cartridge, the liquid distribution and the state of downstream droplets were analyzed, and a new method of setting baffle inside the filter cartridge was proposed. In addition, the optimal baffle height that could greatly improve the performance of filter cartridge was explored. The results show that the saturation of the first layer, especially the lower part, of the filter cartridge decreases with the increase of apparent gas velocity. The dynamic change of apparent gas velocity has a great influence on the saturation of the first and last layers of filter cartridge. Increasing the apparent gas velocity appropriately within the acceptable range of experiment can accelerate the migration of liquid. However, the adhesion of fiber to droplets is relatively weakened when the apparent gas velocity reaches 0.5 m/s, and thus the droplets are easy to detach from the fiber, leading to the re-entrainment and further reducing the filtration efficiency. The baffle structure inside the filter cartridge can effectively avoid the re-entrainment of droplets at high apparent gas velocity. The filtration performance of the filter cartridge is improved most significantly at the baffle height of 15 cm, and the number concentration of downstream droplets is also decreased by 97.3% compared with the structure without baffle. Conclusively, the research results could provide important guidance to the development of efficient coalescence filter cartridge and the optimization of storage and transportation process of natural gas.

Copyright of Journal of Ground Improvement is the property of Journal of Ground Improvement Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Soil erodibility parameter and critical shear stress are important indicators to evaluate the degree of soil erosion sensitivity and the resistance to the shear deformation of water flow. To date, the change of soil erodibility parameter and critical shear stress is unclear in the rill erosion process of saturated loess soil slope. In this study, the maximum rill detachment rates of saturated loess soil slope were determined by a series of soil scouring experiments in the laboratory under different slopes (5°, 10°, 15°, and 20°) and flow rates (2, 4, and 8 L/min). Then, the numerical, modified numerical, and analytical approaches were utilized to calculate the soil erodibility parameters and critical shear stresses. The results showed that the maximum rill detachment rates calculated by the three methods increased with the increase of slope and flow rate over saturated loess soil slope, and the maximum rill detachment rates calculated by the modified numerical method were similar with those calculated by the analytical method. The soil erodibility parameters were 0.470, 0.278, and 0.256 s/m, respectively, and the critical shear stresses were 1.502, 1.306, and 1.367 N/m², respectively. The modified numerical method improved the calculation accuracy, thus the modified numerical calculation was close to the theoretical value calculated by the analytical method. The soil erodibility parameters of saturated loess soil slope decreased by 16.83%, and the critical shear stresses decreased by 66.97%, compared with those of non-saturated loess soil slope in the same study area. Soil saturation had no significant effect on the soil erodibility parameters, while greatly reducing soil critical shear stress, and then leading to serious soil erosion on loess soil slope. Besides, the critical shear stresses of the saturated loess soil slope were 6.38% larger than those of the saturated purple soil slope, and the soil erodibility parameters of the saturated loess soil slope were 2.26 times those of the saturated purple soil slope. These results indicated that the soil saturation had similar effects on the critical shear stress of the two soils, while the saturated loess soil was more sensitivity on soil erosion than the saturated purple soil. These findings can provide some references to optimize the rill erosion model parameters in different soil slopes under the condition of saturations. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Guangdong University of Technology is the property of Journal of Guangdong University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Sciencepaper is the property of China Sciencepaper and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Natural Gas Geoscience is the property of Natural Gas Geoscience and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of China Medical University is the property of Journal of China Medical University Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to determine the spontaneous combustion and thermal characteristics of hydrated coal during saturation to air drying, the combined experimental method of TG-DSC was adopted to research the thermodynamic parameters, activation energy and spontaneous combustion phase of coal samples with different moisture contents during air-drying of hydrated coal. The results show that the oxidation kinetic parameters of the hydrated coal during air-drying generally have a tendency of decreasing-increasing-decreasing at low temperature, but the influence of air-drying degree after reaching high temperature is not significant; the particle size of hydrated coal decreases, oxygen uptake and heat release increase, characteristic temperature and activation energy decrease, and spontaneous combustion period is shortened; in the process of drainage, spontaneous combustion period reduced to a smaller value and then increased, and the minimum value of spontaneous combustion period exists in the water content of 13.01%-14.87%. In the process of safety drainage of coal mine goaf, the degree of drainage should be reasonably determined according to the actual fire prevention arrangement and mining situation, so as to ensure that the residual coal will not develop into spontaneous fire due to excessive water drying.

The sandy clayey purple soil is widely distributed in the middle and upper reaches of the Yangtze River, serving as one of the main soil resources in the mountainous areas of southwest China. Intense physical weathering, loose structure, and low erosion resistance are the main characteristics of sandy clayey purple soil. Therefore, environmental disturbance, such as the water fluctuation near reservoirs, heavy rainfall, and groundwater, often induces soil erosion, landslide, settlement, and soil-water disasters of purple soil. A serious threat has been posed on the village buildings and roads, even the agricultural production. The properties of water immersion disintegration with the sandy clayey purple soil can also be an important reason for water and soil disasters in the southwest mountainous areas. It is necessary to clarify the disintegration characteristics and reinforcement for the water-soil disasters prevention and control. In this study, a disintegration test was performed on the purple soil samples with different initial dry densities, water content, and grain gradation using a self-developed instrument. Meanwhile, the disintegration and evolution of sandy clayey purple soil were also analyzed from the perspective of unsaturated effective stress. Bacillus megaterium was selected to reinforce the soil samples with the Microbial Induced Calcite Precipitation (MICP), as the more suitable as Sporosarcina pasteurii in the sandy clayey purple soil areas. A Scanning Electron Microscope (SEM) was then utilized to characterize the morphologies of the soil sample, thereby determining the MICP improvement on the disintegration characteristics of sandy clayey purple soil. The results show that: 1) Four stages were divided in the whole process of immersion and disintegration of sandy clayey purple soil, including the air-water conversion, equilibrium, disintegration development, and disintegration residual stage. 2) The initial dry density, water content, and grain gradation obviously affected the disintegration characteristics of sandy clayey purple soil. Specifically, the disintegration rate and the average disintegration velocity decreased, with the increase of initial dry density and water content. In addition, the average disintegration velocity of soil increased by the content of fine particles. 3) The evolution of water and air was ranging from the pore water closed, double connected, and pore air closed morphology, with the increasing of the initial saturation. Water was rapidly absorbed into the pores under the matric suction, where the pore pressure was changed significantly. Subsequently, the effective stress of unsaturated soil rapidly reduced to the negative, leading to an interparticle compressive stress (the negative tensile stress). Once the tensile stress reached the value of effective cohesion, the unsaturated strength of purple soil was lost completely. Finally, the soil sample was then destroyed under disintegration. The more severe disintegration was also obtained with the decrease in the initial saturation of a soil sample. The decay process of the unsaturated effective stress depended greatly on the initial saturation after the purple soil was immersed in water. Specifically, the average disintegration velocity attenuated exponentially with the increase of the initial saturation. 4) The disintegration rate and the average disintegration velocity of the MICP treated soil samples decreased by 73 to 97 percentage points and 84%-99%, respectively, compared with the untreated soil. Calcium carbonate crystals formed by solidification and deposition greatly reduced the micro-cracks and large pores in the soil structure. As such, a denser pore structure was achieved to enhance the strength of intergranular cementation for the higher resistance to the disintegration of the soil. Consequently, the MICP technology can serve as an effective measure to prevent the water and soil disasters of the sandy clayey purple soil in southwest mountainous areas. [ABSTRACT FROM AUTHOR]

Copyright of Bulletin of the Chinese Ceramic Society is the property of Bulletin of the Chinese Ceramic Society Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Electric Machines & Control / Dianji Yu Kongzhi Xuebao is the property of Electric Machines & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of CT Theory & Applications is the property of Editorial Department of CT Theory & Applications and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Advances in New & Renewable Energy is the property of Editorial Office of Advances in New & Renewable Energy and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order Lo solve the problem that the detection result of apple color by machine vision is easily affected by the brightness of the picture, an algorithm of apple skin color rate detection based on H - S histogram is proposed in this study. The algorithm use a small number of samples of red, green and yellow colors to generate different H - S histograms. When detecting the coloring rate, the hue value and saturation value of each pixel in the image are extracted, and the H - S histogram is used to analyze the proportion of the red area on the surface of the apple to obtain the coloring rate of the apple surface. The test results prove that this method can effectively detect the coloring rate of the apple surface. The detection results obtained are basically consistent with those observed by human eyes. The average error is less than 8. 3%, and the detection results are not easily affected by the brightness of the picture. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Heilongjiang University of Science & Technology is the property of Journal of Heilongjiang University of Science & Technology Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Advances in New & Renewable Energy is the property of Editorial Office of Advances in New & Renewable Energy and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Harbin University of Science & Technology is the property of Journal of Harbin University of Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Natural Gas Industry is the property of Natural Gas Industry Journal Agency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Industrial Minerals & Processing / Huagong Kuangwu yu Jiagong is the property of Industrial Minerals & Processing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The humification coefficient of input organic material（h）and decomposition rate（k）of soil organic carbon（SOC）are two key parameters that control the SOC turnover processes. Many previous studies have investigated how elements such as water and temperature can affect these processes, but how the SOC content can affect its own turnover processes is seldom concerned. We developed computer models to test the effect of the SOC content on the SOC turnover processes and its underlying mechanisms. The results showed that however h and k changed the SOC content, it also changed asymptotically with time, and eventually reached equilibrium; When assuming that these two parameters were constant with the SOC content, the SOC content would linearly increase without being limited by the C input level; The SOC content would increase asymptotically with the C input level when assuming that h decreased with the SOC content and k increased simultaneously; An asymptotic relationship between the SOC content and C input level would occur. The changes in h and k with the SOC content were termed as negative feedback to SOC turnover. Further study on the mechanisms underlying the negative feedback supported the asymptotic relationship between the SOC content and C input level. We suggest that the negative feedback of SOC turnover is reasonable, and it is necessary and possible to consider this effect in model development. [ABSTRACT FROM AUTHOR]

The single image haze removal algorithm based on dark channel priori is currently the most efficient image defogging technology. However, when the image does not fully satisfy the dark channel priori, many artifacts and color distortion will appear in the processed image, so that the method should be modified according to the image situation. This paper proposed the hypothesis that the brighter the scene, the less credible the dark channel priori would be; the lower the scene saturation, the less credible the dark channel priori would be. Based on this assumption, this paper designed an image's dark channel confidence to limit the dark channel value when the scene didn't fully satisfy the dark channel prior. Furthermore, the image was post-enhanced to improve the visual effect. It selected three typical fog weather images to verify the effectiveness of the proposed method. The experimental results show that the proposed algorithm performs better in preserving color and removing artifacts comparing to some current related defogging algorithms. A new dark channel confidence calculation method is designed to overcome the problem that the estimation of dark channel value will be too large when the image scene does not fully satisfy the dark channel priori. The proposed method improves the adaptability of the dark channel priori defogging model to different foggy scenes. [ABSTRACT FROM AUTHOR]

Copyright of Electronic Components & Materials is the property of Electronic Components & Materials and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of East China University of Science & Technology is the property of Journal of East China University of Science & Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Chongqing University of Posts & Telecommunications (Natural Science Edition) is the property of Chongqing University of Posts & Telecommunications and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Special Oil & Gas Reservoirs is the property of Special Oil & Gas Reservoirs Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of CT Theory & Applications is the property of Editorial Department of CT Theory & Applications and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

For the purpose of investigating the influence of saturation effect on the estimation of regional sensible heat flux by using large aperture scintillometer (LAS), a field test was conducted from August to September, 2014. The dual-optical-path BLS900 scintillometer, which possesses saturation resistance, was set as a reference, and the ZZLAS type scintillometer with aperture size of 0.075 m (LAS1) and 0.15 m (LAS2) was selected as research object. In this field test, the LAS1 was set as easily as possible to be saturated. The saturation correction coefficients calculated based on the optical propagation theory, and the real-time saturation correction coefficient calculated by BLS900 were also displayed, and the air structure parameters, heat fluxes measured from scintillometer were corrected with the coefficients in this study. Variables from LAS1 and LAS2 and that from BLS900 were compared and analyzed with fitted line, as well as root mean square error before and after correction, and F-test was also used in the test of sensible heat flux. The saturation of scintillometer is often caused by the turbulence, and the scale of turbulence is thought to the main reason. Based on the optical propagation theory, inner scale of turbulence was also taken into consideration and the saturation correction coefficient of ZZLAS scintillometer was calculated. The results from the observation were corrected, and comparisons and analysis were also made. Here are the findings. Saturation correction coefficients of LAS1 and LAS2 are 1.034 and 1.019 respectively. The real-time correction coefficients given by BLS900 range from 0.70 to 1.15 depending on the developing of turbulence. The calculated coefficient of BLS900 during 10:00-12:30 shows smaller difference with the real-time coefficients, and it is thought to be more suitable for this period. During the observation, the saturation rate of the LAS1 is 24.58% and the effective saturation correction rate is 12.87%. After correction, root mean square error of air refraction index changes from 1.003×10-13to 9.74×10-14 m-2/3, while there is no change occurring in R2. There is no obvious change of the air structure parameters between LAS2 and BLS900 due to that the saturation rate of LAS2 is much less than LAS1. Sensible heat fluxes from ZZLAS type scintillometer are compared to the results from BLS900, and the root mean square error of LAS1 is 25.67 W/m2. By contrast, the saturation rate of LAS2 is 2.04% and the saturation correction rate is only 0.32%, and there is no significant difference for LAS2 before and after correction. It indicates that, the more pronounced the saturation phenomenon, the more pronounced the effect of saturation correction; this is consistent with the opinion that there is no need to do corrections when the saturation data are less than 5%. Sensible heat fluxes measured from LAS1 exceed 50 W/m2, the corrected fluxes are more close to the reference, and the system error decreases. Sensible heat fluxes from BLS900 and LAS1 are analyzed with F-test and the P value obtained is 0.15, which means there is much difference between the 2 datasets. The P value becomes to 0.004 when the saturation data are corrected with the calculated coefficient, while the P value changes to 0.06 when saturation data are corrected with the real-time coefficients. After correcting the saturation correction coefficient obtained by experiment, the error range of sensible heat flux with reference standard is 1.28-53.42 W/m2, which is closer to the reference standard than that before correction. The results of the observation over the farmland and plantation are also verified by the saturation correction method in the paper. Results also showed that the sensible heat flux observed by the scintillometer after saturation correction is closer to that of the BLS900. When saturation data of the ZZLAS type scintillometer exceed 20%, there is significant improvement on sensible heat flux after the correction with the correction coefficient calculated by the optical propagation theory. [ABSTRACT FROM AUTHOR]

The permeability of soil is an important index to evaluate its antifreeze performance. Under the conditions of freeze-thaw cycles, the change in soil structure and pore characteristics can lead to varied permeability. In order to study the permeability evolution law of unsaturated clay affected by freeze-thaw, several permeability tests were conducted on clay samples with different saturation and different compactness under freezing and thawing cycle. The results show that the permeability coefficient of clay grows quickly then steadily by the end as the number of freezing-thawing rises; what’s more the tendency is proven to be influenced by saturation and density. The higher the saturation is, the greater the osmotic coefficient increment and the growth rate are. The higher the density is, the smaller the effect of freeze-thaw on permeability is and the faster the permeability coefficient reaches steady state during freezing and thawing process. Based on the above experimental results, an osmotic coefficient evolution model including freeze-thaw frequency, saturation and compactness is proposed. [ABSTRACT FROM AUTHOR]

Copyright of Computer Measurement & Control is the property of Magazine Agency of Computer Measurement & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Remote Sensing is the property of Editorial Office of Journal of Remote Sensing & Science Publishing Co. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Natural Gas Industry is the property of Natural Gas Industry Journal Agency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Natural Gas Industry is the property of Natural Gas Industry Journal Agency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Natural Gas Industry is the property of Natural Gas Industry Journal Agency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)