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The changes of wetting and microstructure of loess under unloading from macroscopic and microscopic viewpoints was investigated. The wet subsidence test was conducted on the loess in Tongchuan area, and the wet subsidence coefficients of constant pressure and unloading were measured at different burial depths, and the differences between constant pressure and unloading and wet subsidence coefficients were compared, and the microstructural changes of wet subsided loess were analyzed by combining SEM( scanning electron microscope) and PCAS( particles and cracks analysis system) observations, and the characteristics of changes in microscopic parameters such as pore area percentage, probability entropy and average shape coefficient were obtained at different burial depths and unloading. The results show these as follows. Unloading will effectively increase the initial pressure of wet sink and reduce the occurrence of wet sink, and change the pore area, particle distribution and arrangement of wet sink loess compared with the constant pressure condition; the microstructure is mainly lamellar and honeycomb structure, with the increase of burial depth and unloading amount, the pore space increases from sparse to dense, and the percentage of fine pore space increases; the probability entropy gradually increases, the particle arrangement becomes chaotic and poorly oriented, and the degree of homogenization. There is a strong correlation between the wetting coefficient, burial depth and unloading volume of loess under the unloading effect. [ABSTRACT FROM AUTHOR]

Copyright of Packaging & Food Machinery is the property of Packaging & Food Machinery Magazine 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 investigate the effect of intermediate principal stress on the progressive damage and permeability characteristics of unloading sandstone, the unloading test was carried out under different intermediate principal stress conditions based on a multifunctional true triaxial fluid-solid coupling test system with gas-bearing sandstone as the research object; the exponential permeability model related to the cracked volume strain and damage variable were obtained. The results show that the crack closure stress, crack initiation stress and damage stress increase with the increase of intermediate principal stress, and the percentage of elastic section and microcrack extension stage in the pre-peak strain increases. The deformation in the direction of the intermediate principal stress is restrained in the microcrack extension stage, and the compression effect on the direction of the minimum principal stress is enhanced with the increase of the intermediate principal stress; in the macroscopic crack extension stage, the damage stress is closer to the peak stress, and the damage of the specimen is brittle in character. With the increase of the intermediate principal stress, the initial permeability reduction shows a decreasing trend and the point of elevated permeability shifts backward.

In this paper, true triaxial loading and unloading tests under different principal stress conditions were conducted to study the mechanical properties, failure characteristics, and energy evolution laws of coal bodies that are prone to ejection under different loading and unloading paths, aiming to reveal the ejection mechanism of the surrounding rock of roadway that is prone to ejection after excavation and unloading. The results are as follows. Firstly, the damage of coal samples that are prone to ejection was more severe under high stress single-sided unloading than under loading; when the axial pressure is 90% of the peak value, a large shear crack appeared on the surface of the coal samples, the axial strain rate is high, its own damage degree is large, and the ejection phenomenon was obvious; when the axial pressure was 80% and 70% of the peak value, respectively, the coal samples did not undergo overall macroscopic damage, the axial strain rate is low, and the degree of damage is small, only generated tensile cracks on the free face, and the ejection phenomenon was not obvious. Secondly, the increase of the second principal stress had a reinforcing effect on coal samples that are prone to ejection within a certain range, the internal composite cracks of coal samples that are prone to ejection first increase and then decreased, and the failure mode changed from shear failure to tension-shear composite failure, and finally developed into splitting failure; the intensity of ejection first increased and then decreased. Thirdly, in the process of high stress unloading failure, elastic energy was converted into dissipated energy and released instantly, and the proportion of elastic energy increased sharply, causing the fragments being ejected from the mother body with energy; there were obvious cross mesh cracks in the free face, and the ejection phenomenon was obvious. Fourthly, for coal samples that are prone to ejection under high stress after unloading, the tension-shear cracks rapidly expanded and connected, resulting in tension-shear composite failure, and the ejection phenomenon was obvious; Fifth, tension-shear cracks appear in ejectable coal samples of after unloading, RA increased sharply and AF decreased continuously, AE showing the characteristics of high energy, high meter, high amplitude and high frequency. The study results can provide reference for the on trol of micro impact phenomena in unloading surrounding rock during excavation of similar underground engineering.

Copyright of Modern Food Science & Technology is the property of Editorial Office of Modern Food 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 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 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.)

The intermediate principal stress and unloading have an important influence on the shear failure characteristics of rock. Based on the multifunctional true triaxial fluid-structure interaction test system, the loading and unloading failure tests of sandstone under different intermediate principal stress conditions were carried out. The deformation characteristics and strength characteristics were analyzed, and the influence of the two on the angle of shear deformation zone was studied by establishing the constitutive relationship and the shear deformation zone angle prediction model. The test results show that with the increase of intermediate principal stress, the deflected shear stress at the peak of the rock sample increases, and the increase under unloading conditions is small. The maximum compression point of the rock sample shows a trend of increasing first and then stabilizing, and after reaching the maximum compression point, the volume strain of the rock sample gradually changes from expansion to compression under loading conditions, while the expansion trend occurs under unloading conditions. With the increase of intermediate principal stress, the deflection shear strain of the rock sample increases sharply, and the steep increase under unloading conditions occurs early. At the peak, the stress and strain Lode angles under the unloading condition are larger than those under the loading condition, and the difference between the two types of Lode angles under the two conditions increases with the increase of the intermediate principal stress. The intermediate principal stress and unloading can reflect the yield characteristics of the rock through the stress Lode angle, and reflect the internal fracture evolution direction of the rock through the strain Lode angle. The equivalent plastic strain was used to characterize the internal friction angle and dilatancy angle, and to establish a hardening intrinsic relationship consisting of three stress invariants. Comparing the experimental values, it was found that the model predicted well. With the increase of the intermediate principal stress, the angle of the deformation zone first decreases and then stabilizes. The unloading effect will reduce the angle of the deformation zone, and the angle decrease level is reduced under the influence of the intermediate principal stress.

Dynamic unloading is instantaneous, and the transient unloading effect has important influence on deep rock blasting excavation. In order to study the deformation law and failure mechanism of surrounding rock under dynamic excavation with unloading condition. And tunderstand further dynamic characteristics and the dynamic effects of transient unloading in rock mass excavation. There used a self-developed simulation test device for simulating the process of dynamic excavation in confining pressure loading. The experimental model was made similar material, and used the test device to impact it. It focus on monitoring the unloading effect in real time with the help of strain gauge, high-speed camera and fiber grating sensor. These devices that monitored effective strain-time curves, crack propagation image and the tensile state or compressive state of rock mass after excavation. The test results show that surrounding rock stress of model have experienced five stages that were called initial stress stage, dynamic loading stage, dynamic unloading stage, initial stress unloading stage and creep stage respectively. After model was impacted, each monitoring point occured different strain variation, and some occured compressive strrain, others occured tensile strain. The whole model in compressived state. The model showed creep phenonmen after excavation. Through observing crack propagation image, crack propagation process shown clearly. Firstly, radial cracks were rapidly generated during dynamic excavation. Then, with the free face increase constantly, the stored energy of surrounding rock of model was rapidly released toward the free face, resulting in annular crack occured. Annular crack belongs to tensile faiure, which was generated in vertical radial crack direction and propagated along the adjacent radial crack. Finally, annular crack was parallelled with the free face. The simulation test device system monitored the unloading effect of rock-like marterial well in whole time. Unloading strain value varied with distance, the rock mass model can be divided into near unloading area, middle unloading area and far unloading area after excavation.

Raw materials are usually stored in the form of particles in silos, such as the food, chemical, and pharmaceutical field. The motion of granular materials can vary greatly in the flow of gases and liquids, due to their discrete particle aggregates. It is difficult to accurately explain using traditional theories, such as solid or fluid mechanics, and condensed matter physics. Particularly, the silo can serve as one of the most important carriers to store the particulate matter. It is still lacking in a comprehensive unified theory for the silo subjected to complex forces. Among them, the irregularity of rice seeds has a significant impact on the unloading in the silo, due to the nature of loose particles. Therefore, it is of great significance to clarify the impact of rice seed discharge flow in the silo. Auxiliary devices can also be added to transform the central into the overall flow bin. Simple and effective fluid modification can be used to adjust the structure of silos for the better particle flow. This study aims to explore the impact mechanism of different fluid modifications on the flow of rice seed particles during discharge in the silo. The transformation of the population flow pattern was achieved from the central to the overall flow for better population flow. The discrete element method (DEM) was selected to construct the traditional silo, vertical disturbance, and horizontal disturbance silo models. Rice seed particle models were established for the discharge simulation. The flow pattern was compared with the actual discharge experiment in the silo. A series of experiments was also conducted to verify the accuracy of the discrete element model and numerical simulation. The mass flow index (MFI) and z-axis particle velocity indicated that the particle velocity in the central region of traditional and vertically disturbed silos decreased with the increase of particle stacking height, whereas, the particle velocity increased in the sidewall region. There was a decrease in the particle velocity in the sidewall area of the horizontally disturbed silo, as the particle stacking height increased, whereas, the particle velocity increased in the central area. Traditionally, the conversion heights of the flow pattern were 130, 118, and 130 mm, respectively, in the vertically and horizontally disturbed silos. There was a variation in the vertical, horizontal, and angular velocity in the different areas of the silo. Specifically, the vertical velocity of the population decreased by 34.82% and 83.46%, respectively, compared with the traditional flow area of the silo under the action of the vertical and horizontal fluid. The fluctuation of population horizontal velocity increased, as the height of particle accumulation decreased in the silo population. The standard deviations of particle horizontal velocity were 0.027 3, 0.018 7, and 0.010 3, respectively, in the traditional silos, vertical and horizontal disturbance silos. There were similar changes in the particle angular velocity in the center and sidewall areas of traditional and vertical disturbance silos. The peak angular velocity was smaller in the center area of vertical disturbance silos, compared with the traditional silos. The variation of particle angular velocity was similar to the traditional silo in the flow area of a horizontal disturbance. But there was a small variation of particle angular velocity in a horizontal disturbance silo. The finding can provide the theoretical reference for the fluid design standards, structural and positional parameters, particularly for the high available area of the silo. [ABSTRACT FROM AUTHOR]

Considering the stress paths of kilometer-deep granite during mining， the triaxial loading and unloading experiments are performed on granite under three stress paths: ascending axial pressure and fixed confining pressure， ascending axial pressure and unloading confining pressure， and fixed axial pressure and unloading confining pressure. The aim is to obtain the deformation and failure characteristics and energy evolution law of rock under mining and unloading conditions. The research results show that under the high confining pressure levels， rock stores more energy before reaching peak failure， and the deformation energy released during failure has a more significant impact on the rock structure， leading to brittle failure of the rock sample. The unloading effect weakens the radial restraint of the confining pressure on the rock sample， causing an increase in radial expansion， and failure occurs at a lower stress level. Furthermore， the rock deformation modulus and generalized Poisson’s ratio reach the extreme point faster， determined by the expansion point， the turning point at which the proportion of elastic energy of the rock sample changes from increasing to decreasing. Compared with the ascending axial pressure and fixed confining pressure test， the ratio of elastic energy to dissipated energy is higher under the unloading conditions， resulting in more severe in rock damage. [ABSTRACT FROM AUTHOR]

Objective To investigate the highlights of establishing a rat model of mimicking left venticular assist device （LVAD） by unloading rat infarcted hearts. Methods 29 adult Lewis rats were ligated the left anterior discending arteries to shut the blood supply of myocardium to establish the infarcted heart failure rat models. Electrocardiogram （ECG） was performed to screen the rat models with heart failure. 24 heart failure rats were randomly divided into the unloading group （n = 14） and heart failure group （n = 10）. Heart transplantation was not performed in the heart failure group. In the unloading group, the hearts of heart failure rats were prepared for heterotopic cardiac transplantation into the inferior vena cava and abdominal aorta of the recipient rats to establish the left ventricular unloading models. In the blank control group （n = 8）, the rats were intervened with open surgery alone. The remaining interventions were similar to those in the other two groups. At 2 weeks after cardiac transplantation, the left ventricular end-diastolic pressure （LVEDP）, maximum left ventricular pressure rising/falling rate （±dp/dtmax） and left ventricular systolic pressure （LVSP） were measured. Histological changes of the rat hearts were observed. Results The success rate of heart failure rat models after ischemic cardiomyopathy was 82.76% （24/29）. The survival rate of heart failure rats after cardiac unloading was 71.43% （10/14）. Compared with the heart failure group, the left ventricular developed pressure （LVDP） was significantly elevated （47.85±0.94 vs. 35.94±0.95,F = 250.993, P < 0.05） and the ±dp/dtmax was significantly increased （1177.85±61.03 vs. 841.64±40.26,F = 942.304,P < 0.05） in the unloading group. Conclusion The rat models with heart failure can be established by myocardial infarction and subsequently receive heterotopic heart transplantation, which offers an economical and reproducible model of ventricular unloading.

Copyright of Advanced Engineering Science / Gongcheng Kexue Yu Jishu is the property of Advanced Engineering Science 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 Guangdong Architecture Civil Engineering is the property of Guangdong Architecture Civil Engineering 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.)

On the basis of the elastic, first elastic-plastic, second elastic-plastic and plastic deformation states of asperity, and considering the influence of friction factors, we established a fractal theoretical model of contact area and contact load of a single asperity during loading and unloading at each deformation stage. Parameters were introduced: distribution density function correction coefficients Ce, Cep1, and Cep2, and contact load correction coefficients De, Dep1 and Dep2, of the joint interface at each deformation stage, and then the actual contact area and contact load fractal theoretical models of the loading and unloading process of the joint interface at each deformation stage under the consideration of friction factors were deduced. According to the models, the actual contact area and contact load of the joint interface in the loading-unloading process are related to the friction correction factor, yield limit, equivalent elastic modulus, contour parameter, fractal dimension, and frequency parameter of rough surface, while those in the unloading process are also related to the maximum deformation and residual deformation after unloading.

Copyright of Guangdong Architecture Civil Engineering is the property of Guangdong Architecture Civil Engineering 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.)

To explore the dynamic fracture regularities of coal body under abrupt unloading with consideration of roof subsidence, the discretized virtual internal bond method was used to simulate the dynamic fracture process of the rock-coal-rock body under unloading condition. It was found that the dynamic fracture exhibited three-stage characteristics, namely the initial, the stable and the accelerated failure stage. With consideration of the roof subsidence, a quantitative fracture evolution function was drawn. With the initial in-situ stress increasing, the dynamic fracture in the initial and the accelerated failure stages was more violent, and the duration of the stable failure stage became shorter. The roof subsidence rate had little effect on the initial failure stage. With the roof subsidence rate increasing, the dynamic fracture in the stable and the accelerated failure stages was more violent. With the surrounding rock stiffness increasing, the duration of stable failure became longer. These findings provided valuable reference for the prediction of coal burst. [ABSTRACT FROM AUTHOR]

Copyright of Guangdong Architecture Civil Engineering is the property of Guangdong Architecture Civil Engineering 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 Guangdong Architecture Civil Engineering is the property of Guangdong Architecture Civil Engineering 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 solve problems of large labor intensity and low efficiency existed in durability test process of internal injection type single prop with manual loading and unloading method, a set of automatic loading device of durability test of internal injection type single prop was developed. The device uses measurement and control software for industrial personal computer to control servo motor and speed reducer to drive load tooling rotate, realizes operation of lifting and falling prop of internal injection type single prop by the servo motor driver, and automatically control loading process of the prop; uses the servo motor to drive unloading handle to achieve operation of unloading and falling prop. The device can also realize precise control of load speed, torque, position of the motor to prevent overload and locked-rotor of loading mechanism. The test results show that the control device has high control accuracy, fast loading speed, stable and reliable performance, which improves automation level of durability test of the internal injection type single prop.

Principles and shortcomings of balance jack control of hydraulic support by use of compensation valve, high pressure internal overflow valve, floating two-way lock and automatic balance valve respectively were analyzed, and an optimal design scheme of the balance jack control loop of hydraulic support was proposed according to pressure characteristics of the balance jack cavity. Automatic fluid replacement and unloading of the balance jack cavity are realized by reasonably disposing components such as hydraulic pressure controlled reversing valve and low pressure unloading valve, so as to solve problem of safety valve frequently opening under non-emergency situation. The simulation and test results verify effectiveness of the optimal design scheme.

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute 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 Tunnel Construction / Suidao Jianshe (Zhong-Yingwen Ban) is the property of Tunnel Construction 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 Guangdong Architecture Civil Engineering is the property of Guangdong Architecture Civil Engineering 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 study the process of large-scale overlying strata collapse under the influence of mining in a certain mining area on the basis of the study of macroscopic rock mechanics parameters, the dynamic development process of large-scale overlying rock collapse and caving under the condition of continuous excavation and unloading in different middle sections is analyzed by using the discrete element method program 2D-Block. The simulation results show that with the continuous mining of the deep orebody, the overlying rock mass cave and collapse scope increases gradually, the collapse of overburden strata has a certain hysteresis. The maximum collapse range of overburden strata are respectively 25 m, 42 m and 42 m after 13, 14 and 15 middle sections are mined; the maximum collapse range of overlying rock are respectively 76 m, 97 m and 110 m after 16, 17 and 18 middle sections are mined. [ABSTRACT FROM AUTHOR]

Copyright of Tunnel Construction / Suidao Jianshe (Zhong-Yingwen Ban) is the property of Tunnel Construction 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 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 Journal of Henan University of Technology Natural Science Edition is the property of Henan University of Technology Journal 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.)

In order to thoroughly explore the internal response characteristics and the catastrophic behaviors of rock mass caused by unloading in deep excavation process, the self-developed triaxial acoustic emission acquisition system is used to conduct the triaxial unloading tests of sandstone with different unloading rates and different confining pressures. Seismic statistics method is used to analyze the parameters such as absolute energy E and waiting time δ. The results show that: (1) the probability density function of absolute energy released in the unloading follows a power law distribution well in the range of 101 a J to 104 a J. (2) With the decrease of unloading rate, the possibility of small energy events occurrence is increasing. There is a similar trend with the increase of confining pressure in the same unloading rate. (3) The "after-shock"of acoustic emission events meets the same linear relationship under different confiningpressures and unloading rates, and it is not affected by the fluctuation of the "main shock" events energies. (4) In a short time interval range( less than 0.1 s), the power exponent is not affected by confining pressure and unloading rate. For a long interval range( greater than 0.1 s), the power exponent fluctuates in the range of 1.3 to 1.9. The distributions of waiting time for different energy thresholds show universality well. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Mine Automation is the property of Industry & Mine Automation 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 Journal of Mine Automation is the property of Industry & Mine Automation 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.)

The test machine MTS 815 was applied to carry out cyclic loading-unloading experiments for coal-rock combined body.The axial crack recovery effect was analyzed and the axial crack closure stress (strain) and recovery stress (strain) were obtained.The results show that the axial crack closure stress (strain) and axial crack closure recovery stress (strain) increase with increasing cyclic times.Due to the increase of stress level,new cracks are generated,and the axial crack closure strain difference,axial crack recovery strain difference and axial crack stress difference increase with increasing cyclic times.Based on natural strain and engineering strain,the axial crack recovery model is proposed and verified by experimental data.The good agreement between theoretical data and test data shows the model is reasonable.Also,the proposed model can describe the axial crack recovery effect during unloading process well. [ABSTRACT FROM AUTHOR]

The characteristics of shipping liquefied natural gas (LNG) as well as the difference between LNG and general merchandise measurement in trade, and the necessity of energy calculation, are introduced in this paper. Analysis and introduction of the method and step of a series of detection methods, such as the calculation of tank capacity, liquid density, unloading energy and mass, and unit heating value, provide a practical reference for the detection of liquefied natural gas. [ABSTRACT FROM AUTHOR]

In order to overcome the deficiency in the design of horizontal frozen wall，an elastic mechanical model was established for understanding the interaction between circular horizontal frozen wall and surrounding rock，with the consideration of the excavation unloading effect of rock and soil inside frozen wall. At the same time the analytical solutions of stress and displacement were obtained. The stress on the inner edge of frozen wall was analyzed emphatically and the formula for calculating frozen wall thickness was put forward based on different yield criteria.The influence of various factors was also discussed. The analysis shows that the frozen wall thickness can decrease significantly with the consideration of the interaction. The frozen wall becomes thinner with stronger interaction and larger lateral pressure coefficient and becomes thicker with the increase of its buried depth. However，the influence of Poisson's ratio on the thickness can be neglected.In addition，the Mohr-Coulomb yielding criterion is suggested to calculate the thickness as frozen soil belongs to geomaterial. [ABSTRACT FROM AUTHOR]

Aiming at the problem of the defect and inefficient of the binder clips automated assembly system assembly loading and unloading process, a new loading and unloading synchronization device which was two-stage intermittent push plate was proposed. This synchronization device was used to realize the function of unassembled clip body loading and assembled binder clip unloading. Using the Siemens S7-200 series PLC controller to roundly control loading and unloading device, transport device and assembly device, the automatic assembly machine were implemented. Based on the loading and unloading cylinder dynamics simulation with the Simulink simulation tool of Matlab, each parameter value in the process of pneumatic launch was determined, and the optimal value of working pressure and the platform assembly efficiency were worked out. The experimental results indicate that the loading and unloading synchronization device has highest work efficiency and the lower fault rate,which can effectively replace manual loading unloading,while the cylinder pressure is 0.2MPa and the loading and unloading time is 0.693s. [ABSTRACT FROM AUTHOR]

Open stockyard is widely adopted as coal temporary storage on traditional coal terminal, which leads to the environment pollution. This paper describes the design and realization of the coal silo storage technology application on coal terminal phase-3 project of Huanghua Port. The new technology brings advantages on environmental protection, energy saving and efficiency increasing by downsizing staff. It can provide references for similar projects. [ABSTRACT FROM AUTHOR]

On the basis of macro unloading test and the micro structure analysis,the unloading soft soil damage variables is defined. By using fractal theory, unloading micro structure evolution law (fine) view of structural soft soil is described quantitatively. The results show that the soil excavation unloading is actually a gradual process associated with damage, and the damage evolution can use fractal dimension D to quantitatively describe; Soft soil unloading process has the trend of fractal dimension decreasing as a whole, reflecting the increasing trend of soft soil damage. In soft soil unloading process, with the increase of unloading level, fractal dimensions of transverse profile of particle size distribution and pore size distribution in the soft soil become smaller, while the change speed in pore position is significantly lower than that in cross-sectional profile. Therefore, particle size distribution fractal dimension and pore size distribution fractal dimension can be used as quantitative description of soft soil unloading damage index. [ABSTRACT FROM AUTHOR]

Goal rock is naturally comprised of a large number of randomly-distributed discontinuities such as joints/ cracks and weak interlayers. The geometry, size, distribution, contact and infillings of the discontinuities essentially govern the physical/mechanical properties and failure mechanism of coal rock. It is intractable to theoretically and accurately characterize the discontinuities and the governing influences on the deformation and failure of coal rock. This paper presented a 3D finite element model of fractured coal rock representing the irregular geometry, complex contact, intersection, and network features of interior joints and cracks by means of high-resolution GT techniques and 3D reconstruction methods. The birth-death clement algorithm was employed to characterize and visualize the stress field distribution, spatial distribution of failed areas, energy dissipation and release during the deformation and failure of fractured coal rock when subjected to the varied unloaded conditions. The analysis discloses the determinative influences of the unloading paths and the properties of joints and cracks on the macro mechanical behavior and the failure mechanism of fractured coal rock. The paper presents a promising way to identify and characterize the governing effect of unloading due to deep excavation on real fractured coal rock. [ABSTRACT FROM AUTHOR]

Based on three typical mining models (non-pillar mining, top-coal caving and protected coal seam mining), a series of triaxial tests which keeping confining pressure at the same unloading rate and axial pressure in different loading rates were carried out on the limestone samples through MTS-815 electrohydraulic servo Rock Test System. Based on experimental results, the relationship between stress path and surrounding rock under different mining conditions was investigated in detail. The complete stress-strain curves and macro-damaged characteristics were studied and compared. The experimental results indicate that the failure mode is mainly related to the confining pressure near peak strength rather than the axial loading rate under unloading condition. The top-coal caving can lead to more bigger deformation and plastic deformation than non-pillar mining and protected coal seam mining. The axial loading rate transform the rock property between brittle and ductile, when the confining pressure is bigger, the conversion of brittle-ductile property will be more obviously. [ABSTRACT FROM AUTHOR]

A new type of structure, called U-shaped steel-concrete composite vierendeel floor where the steel was connected by bolts, was applied in the design of the gymnasium in Heilongjiang University of Chinese Medicine. For this new type of large-span floor, it is necessary to ensure the safety of the structure during unloading process. This paper tested the structural behavior of the U-shaped steel-concrete composite vierendeel floor during unloading formwork support system of the structure. According to the characteristics of the floor grid, a new unloading technique, called traveling quincuncial piles method, was adopted in the unloading project. The deflection of the floor and the stress of the U-shaped steel were mainly monitored during each unloading step. The experimental results show the stress and the deflection of the structure can meet the requirements of code, and the U-shaped steels connected by bolt can not move relatively. The theoretical analysis and design of the structure and the unloading procedure are verified to be effective and reliable. [ABSTRACT FROM AUTHOR]

The differential viscoelastic plasticity constitutive equation with the creational rheological elements in humidity field of rock which considers the influence of humidity was finished based on the Nishihara theological model. The model equation considering humidity effect of creep, unloading and relaxation were deduced. When the stress is less than yield stress, the model is a stable creep model; and the unloading curve contains instantaneous elasticity, elastic after-effect and viscosity flow induced by humidity. When the stress is greater than yield stress, the model is an unstable creep :and the curve of unloading includes instantaneous elasticity, elastic after-effect and the viscosity flow induces by the stress and humidity. The multiaxial creep equation was also established according to equivalent effective strain and stress theory. This model reflects the rheological properties of rock, and can be used for analysis of stability of rocks. [ABSTRACT FROM AUTHOR]