Large-scale model testing of high-pressure grouting reinforcement for bedding slope with rapid-setting polyurethane

Bedding slope is a typical heterogeneous slope consisting of different soil/rock layers and is likely to slide along the weakest interface.Conventional slope protection methods for bedding slopes,such as retaining walls,stabilizing piles,and anchors,are time-consuming and labor-and energy-intensive.This study proposes an innovative polymer grout method to improve the bearing capacity and reduce the displacement of bedding slopes.A series of large-scale model tests were carried out to verify the effectiveness of polymer grout in protecting bedding slopes.Specifically,load-displacement relationships and failure patterns were analyzed for different testing slopes with various dosages of polymer.Results show the great potential of polymer grout in improving bearing capacity,reducing settlement,and protecting slopes from being crushed under shearing.The polymer-treated slopes remained structurally intact,while the untreated slope exhibited considerable damage when subjected to loads surpassing the bearing capacity.It is also found that polymer-cemented soils concentrate around the injection pipe,forming a fan-shaped sheet-like structure.This study proves the improvement of polymer grouting for bedding slope treatment and will contribute to the development of a fast method to protect bedding slopes from landslides.

Mechanical anisotropy associated with beddings in shale under Brazilian test conditions:Insights from acoustic emission statistics

A comprehensive understanding of shale’s bedding anisotropy is crucial for shale-related engineering activities,such as hydraulic fracturing,drilling and underground excavation.In this study,seven Brazilian tests were conducted on shale samples at different bedding orientations with respect to the loading direction(0°,45°and 90°)and the disc end face(0°,45°and 90°).An acoustic emission(AE)system was employed to capture the evolution of damage and the temporal-spatial distribution of microcracks under splitting-tensile stress.The results show that the Brazilian tensile strength decreases with increasing bedding inclination with respect to the disc end face,while it increases with the angle between bedding and loading directions.Increasing the bedding inclination with respect to the end face facilitates the reduction in b value and enhances the shale’s resistance to microcrack growth during the loading process.Misalignment between the bedding orientation and the end face suppresses the growth of mixed tensile-shear microcracks,while reducing the bedding angle relative to the loading direction is beneficial for creating mixed tensile-shear and tensile cracks.The observed microscopic failure characteristics are attributed to the competing effects of bedding activation and breakage of shale matrix at different bedding inclinations.The temporal-spatial distribution of microcracks,characterized by AE statistics including the correlation dimension and spatial correlation length,illustrates that the fractal evolution of microcracks is independent of bedding anisotropy,whereas the spatial distribution shows a stronger correlation.The evolution features of correlation dimension and spatial correlation length could be potentially used as precursors for shale splitting failure.These findings may be useful for predicting rock mass instability and analyzing the causes of catastrophic rupture.

REST API自动化测试综述

REST API已经成为访问和使用云服务、Web、移动应用程序的重要途径,如何对这些API进行自动化测试以保证服务的安全性和可靠性是亟待解决的问题。目前虽然关于REST API自动化测试的研究成果众多,但仍缺少对测试技术全面的分析和总结。梳理了该领域近10年的代表性成果,首先总结了REST API自动化测试的发展历程;然后结合REST API自动化测试特征,提炼了测试的通用流程;接着分别从预处理、测试用例生成、测试用例执行与监测、结果分析四个环节阐述现有成果的技术特征,对比分析其优缺点;最后论述当前研究存在的不足,讨论可能的解决思路,展望了下一步研究方向。

Influence of unsupported sleepers on the dynamic stability of ballasted bed based on wheelset impact tests

The unsupported sleeper can change the load characteristics of ballast particles and thus affect the dynamic stability of a ballasted bed.In this work,a laboratory test was constructed on a ballasted track containing unsupported sleepers.The ballasted track was excited by a wheelset,and the influence of unsupported sleepers on the dynamic stability of a ballasted bed was studied.The results show that the main frequency of the sleeper vibration appeared at 670 Hz,and the first-order rigid vibration mode at the frequency of 101 Hz had a significant effect on the condition without the unsupported sleeper.When the sleepers were continuously unsupported,the vibration damping effect of ballasted bed within the frequency range of 0–450 Hz was better than that at higher frequencies.Within the frequency range of 70–250 Hz,the vibration damping effect of the ballasted bed with unsupported sleepers was better than that without the unsupported sleeper.Owing to the excitation from the wheelset impact,the lateral resistance of the ballasted bed with unsupported sleepers whose hanging heights were 30,60,and 90 mm increased by 37.43%,12.25%,and 18.23%,respectively,while the lateral resistance of the ballasted bed without the unsupported sleeper remained basically unchanged.The unsupported sleeper could increase the difference in the quality of the ballasted bed between two adjacent sleepers.In addition,test results show that the hanging height of the unsupported sleeper had little effect on the lateral resistance of a ballasted bed without external excitation,but had an obvious effect on the rate of change of the lateral resistance of a ballasted bed and the acceleration amplitude of the sleeper vibration under the wheelset impact.

基于RESTful架构的气象数据检验接口设计与实现

气象数据质量评价是整个数据链条中的关键一环。为解决目前气象数据检验业务分散滞后、资源不集约及服务效率不高的问题,实现统一服务,基于现代Web应用流行框架RESTful,首次将检验作为Web服务,基于共性检验需求设计并实现RESTful架构风格的气象数据检验接口。统一接口服务将业务资源进行集中,提高物理资源利用率的同时释放人力资源。接口服务以及基于接口开发的检验系统,可实现检验结果秒级在线查询,大大提高检验效率,丰富的接口和可视化系统给用户带来良好体验。

Stability of bedded rock slopes subjected to hydro-fluctuation and associated strength deterioration

Reservoir-induced earthquakes(RIEs)occur frequently in the Three Gorges Reservoir Area(TGRA)and the rock mass strength of the hydro-fluctuation belt(HFB)deteriorates severely due to the reservoirinduced seismic loads.Three models of typical bedded rock slopes(BRSs),i.e.gently(GIS),moderately(MIS),and steeply(SIS)inclined slopes,were proposed according to field investigations.The dynamic response mechanism and stability of the BRSs,affected by the rock mass deterioration of the HFB,were investigated by the shaking table test and the universal distinct element code(UDEC)simulation.Specifically,the amplification coefficient of the peak ground acceleration(PGA)of the slope was gradually attenuated under multiple seismic loads,and the acceleration response showed obvious“surface effect”and“elevation effect”in the horizontal and vertical directions,respectively.The“S-type”cubic function and“steep-rise type”exponential function were used to characterize the cumulative damage evolution of the slope caused by microseismic waves(low seismic waves)and high seismic waves,respectively.According to the dynamic responses of the acceleration,cumulative displacement,rock pressure,pore water pressure,damping ratio,natural frequency,stability coefficient,and sliding velocity of the slope,the typical evolution processes of the dynamic cumulative damage and instability failure of the slope were generalized,and the numerical and experimental results were compared.Considering the dynamic effects of the slope height(SH),slope angle(SA),bedding plane thickness(BPT),dip angle of the bedding plane(DABP),dynamic load amplitude(DLA),dynamic load frequency(DLF),height of water level of the hydro-fluctuation belt(HWLHFB),degradation range of the hydro-fluctuation belt(DRHFB),and degradation shape of the hydro-fluctuation belt(DSHFB),the sensitivity of factors influencing the slope dynamic stability using the orthogonal analysis method(OAM)was DLA>DRHFB>SA>SH>DLF>HWLHFB>DSHFB>DABP>BPT.

Physical model test and application of 3D printing rock-like specimens to laminated rock tunnels

Weak structural plane deformation is responsible for the non-uniform large deformation disasters in layered rock tunnels,resulting in steel arch distortion and secondary lining cracking.In this study,a servo biaxial testing system was employed to conduct physical modeling tests on layered rock tunnels with bedding planes of varying dip angles.The influence of structural anisotropy in layered rocks on the micro displacement and strain field of surrounding rocks was analyzed using digital image correlation(DIC)technology.The spatiotemporal evolution of non-uniform deformation of surrounding rocks was investigated,and numerical simulation was performed to verify the experimental results.The findings indicate that the displacement and strain field of the surrounding layered rocks are all maximized at the horizontal bedding planes and decrease linearly with the increasing dip angle.The failure of the layered surrounding rock with different dip angles occurs and extends along the bedding planes.Compressive strain failure occurs after excavation under high horizontal stress.This study provides significant theoretical support for the analysis,prediction,and control of non-uniform deformation of tunnel surrounding rocks.

I MWth Test Facilities for Circulating Fluidized Bed Combustion

This paper presents the technical parameters and features of 1 MWth test facilities for circulating fluidized bed combustion (CFBC) at Thermal Power Research Institute (TPRI) of State Power Corporation (SP), introduces the test items that can be proceeded and trial combustion projects completed. The development status of CFBC technologies abroad and the level of China in this field are also introduced in the paper.

ISOLATION DESIGN AND SIMULATIONAL EXPERIMENT OF NANOMETER MICRO MOVEMENT TEST-BED

The relation of mass, stiffness and rate of damping is obtained by using the mechanical analysis of the obstructive vibration system of two dimensions for the design of the obstructive vibration system of more freedom and the micro vibration test bed. The result of stimulational experiment indicates that the isolation of vibration of this system is satisfactory. The design method of vibration can be used as the reference to ultra precision machine tool, super micro orientation machanism and so on.

LDRA TestBed在CTCS2-200C扩展单元软件测试中的应用

介绍了LDRA Test Bed软件测试工具和CTCS2-200C扩展单元,以CTCS2-200C为例,通过对软件进行静态和动态测试,参照EN 50128:2011标准,提高了整个软件开发生命周期中的各项验证和确认活动效率,降低了软件的风险。

Anti-oxidation actions of curcumin in two forms of bed rest:oxidative stress serum and salivary markers

Objective:To determine the preventive effects of curcumin on peroxidative damage under two bed rest conditions.Methods:20 healthy male(10 with curcumin and 10 without curcumin ) volunteers were selected.They were studied before,during,and just on bed rest conditions at -6°head-down-tilt(HDT) bed rest and bed rest position(BD) for 10 days.We measured the salivary and serum oxidative markers such as Malonaldehyde,8-hydroxydeoxyguanosine, vitamin C and E just before HDT & BD.during HDT & BD experiment,and in course time of recovery with curcumin and without curcumin groups.Results:The values of serum and salivary vitamin C & E showed statistically significant decrease in both bed rest conditions as compared to those of the conditions before and during the recovery stage.However,these levels were not significantly lowered in curcumin groups in contrast to the groups without curcumin (P】0.05).MDA and 8-OHdG levels showed significant increase in simulating microgravity and zero gravity conditions as compared to those before and in the recovery stage.However,these levels were lower in curcumin groups in contrast to the groups without curcumin(P【0.05).Serum and salivary correlation analysis revealed a strong and highly significant correlation for MDA. vitamin C & E and 8 dihydro-2 deoxyguanosine(8-OHdG) in the conditions before,during and in the recovery periods in both bed rest conditions.Since saliva collection is easy and noninvasive, measurements of salivary marker levels may prove to be useful in the space research. Conclusions:Curcumin prevents peroxidative damage in both bed rest conditions.Further study is required on antioxidation actions of curcumin in space microgravity conditions.

Model test and numerical simulation on the dynamic stability of the bedding rock slope under frequent microseisms

Shake table testing was performed to investigate the dynamic stability of a mid-dip bedding rock slope under frequent earthquakes. Then, numerical modelling was established to further study the slope dynamic stability under purely microseisms and the influence of five factors, including seismic amplitude, slope height, slope angle, strata inclination and strata thickness, were considered. The experimental results show that the natural frequency of the slope decreases and damping ratio increases as the earthquake loading times increase. The dynamic strength reduction method is adopted for the stability evaluation of the bedding rock slope in numerical simulation, and the slope stability decreases with the increase of seismic amplitude, increase of slope height, reduction of strata thickness and increase of slope angle. The failure mode of a mid-dip bedding rock slope in the shaking table test is integral slipping along the bedding surface with dipping tensile cracks at the slope rear edge going through the bedding surfaces. In the numerical simulation, the long-term stability of a mid-dip bedding slope is worst under frequent microseisms and the slope is at risk of integral sliding instability, whereas the slope rock mass is more broken than shown in the shaking table test. The research results are of practical significance to better understand the formation mechanism of reservoir landslides and prevent future landslide disasters.

Safety study of Folfox-HAIC in relieving bed restriction

Objective:To investigate the safety of relieving bed restriction in hepatic arterial infusion chemotherapy(HAIC)and its effects on patient comfort.Methods:A prospective study was conducted.Patients with malignant liver tumors,who met the enrollment criteria,were randomly divided into experimental and control groups.During HAIC treatment,the patients in the experimental group,who were not confined to bed and could get out of bed,used electronic injection pumps to infuse chemotherapy drugs.The patients in the control group,who were strictly confined to bed and prohibited from getting out of bed,used infusion pumps to infuse chemotherapy drugs.The complications of the two groups were observed.The Christenson standard improved method was used to evaluate the bleeding and hematoma of limbs on the operation side.The Kolcaba General Comfort Questionnaire(GCQ)and Barthel Index(BI)were used to evaluate the two groups.Results:Ninety patients with malignant liver tumors were enrolled,including 53 with primary liver cancer and 37 with colorectal liver metastasis.There were 70 males and 20 females,aged 41-81 years old,with an average age of 61.6±9.248 years old.There were 60 patients in the experimental group and 30 patients in the control group.All patients underwent HAIC.The study showed that,during the treatment period,there were 3 cases of postoperative puncture point hematoma formation in the two groups,including 2 cases in the experimental group(2/60,3.3%)and 1 case in the control group(1/30,3.3%).The difference was not statistically significant(p>0.05).There were 5 cases of postoperative puncture point bleeding,including 4 cases in the experimental group(4/60,6.7%)and 1 case in the control group(1/30,3.3%),and the difference was not statistically significant(p>0.05).A total of 23 cases,with 6 cases in the experimental group(6/60,10%)and 17 cases in the control group(17/30,56.7%),complained of back pain after the operation,and the difference was statistically significant(p<0.05).Twenty-one cases complained of poor defecation after the operation,including 10 cases in the experimental group(10/60,16.7%)and 11 cases in the control group(11/30,36.7%).The difference was statistically significant(p<0.05).During the period of infusion chemotherapy,the two groups of patients had there was a significant difference between the two groups in terms of comfort status(GCQ)(88.78±6.705,78.47±9.519,p<0.001)and self-care ability(BI)(74.25±9.152,66.83±6.628,p<0.001).Conclusion:During HAIC treatment,getting out of bed is safe and reliable and can increase the patients’comfort and self-care ability.Hence,it merits clinical application.

Model test of the stability degradation of a prestressed anchored rock slope system in a corrosive environment

The long-term stability of a prestressed anchored slope might be influenced by the durability of the anchorage structure.To understand long-term stability of anchored rock slopes,the research presented herein evaluated the performance evolution of a prestressed anchored bedding slope system in a corrosive environment by model test.The corrosion process in a prestressed anchor bar was monitored in terms of its open-circuit potential(OCP),corrosion current density(CCD),and electrochemical impedance spectroscopy(EIS).The stability of the prestressed anchored slope was evaluated by monitoring changes in anchorage force and displacements.The experimental results show that prestress and oxygen could reduce the corrosion resistance of the anchor bar,and anchor bars in a chloride-rich environment are very susceptible to corrosion.Prestressed tendons in a corrosive environment suffer a loss of anchorage force,the prestress decreases rapidly after locking,and the rate thereof decreases until stabilising;in the later stage,corrosion leads to the reduction of the cross-sectional area of the steel bar which may cause the reduction in anchorage force again.Anchorage force controls the deformation and stability of the anchored slope,the prestress loss caused by later corrosion may lead to an increased rate of displacement and stability degradation of the prestressed anchored rock slope.

Thermal-Hydraulic System Study of the Helium Cooled Pebble Bed (HCPB) Test Blanket Module (TBM) for ITER Using System Code RELAP5

The HCPB concept has been a European DEMO reference concept for nearly one decade. Detailed thermal-hydraulic study on the control behavior of the whole system is one of the important parts of this development. The thermal-hydraulic effect of the TBM-combined cooling circuit during a cyclic operation in ITER has been studied using the system code RELAP5. The RELAP5 is based on an one-dimensional, transient two-fluid model for the flow of a two-phase steam-water mixture that can contain noncondensable components like Helium. The RELAP5models are modified to take the cyclic operation of the circulator, heat, exchanger, bypass, valves etc in to account. A sequence of operational phases is investigated, starting from the cold state through the heating phase that brings the system to a stand-by condition, followed by typical power cycles applied in ITER. The results show that the implemented control mechanisms keep the inlet temperature to the TBM and the total mass flow rate at the required values through all phases.

Feasibility of incorporating a bed-rest exercise program during a twin pregnancy: Case reports

Considering the maternal risk for both short- and long-term disability imposed by activity restriction, it is of great concern that the antepartum symptoms of bed rest are still evident in the postpartum period. The benefits of bed-rest-exercise may alleviate or even prevent physiological distresses or deconditioning associated with activity restriction, thus, eliminating or stabilizing, factors that may augment existing complications. This is the first study to investigate the feasibility of incorporating a bed-rest exercise program in a specific hospitalized twin pregnancy case. The maternal physiological responses of heart rate, blood pressure and uterine contractions to a four week bed-rest resistance program were measured in a woman hospitalized due to complications during her twin pregnancy. A second participant (same diagnoses) was included as a control. The bed-rest-exercise reduced the degree of swelling in the lower extremities, promoted more energy during the day and a better night’s sleep. There were no significant differences in uterine contractions pre vs. post protocol and all babies were born healthy.

Development of a Drilling and Coring Test-bed for Lunar Subsurface Exploration and Preliminary Experiments

Drill sampling has been widely employed as an effective way to acquire deep samples in extraterrestrial exploration. A novel sampling method, namely, flexible-tube coring, was adopted for the Chang＇e mission to acquire drilling cores without damaging stratification information. Since the extraterrestrial environment is uncertain and different from the terrestrial environment, automated drill sampling missions are at risk of failure. The principles of drilling and coring for the lunar subsurface should be fully tested and verified on earth before launch. This paper proposes a test-bed for conducting the aforementioned experiments on earth. The test-bed comprises a rotary-percussive drilling mechanism, penetrating mechanism, drilling medium container, and signal acquisition and control system. For granular soil, coring experiments indicate that the sampling method has a high coring rate greater than 80%. For hard rock, drilling experiments indicate that the percussive frequency greatly affects the drilling efficiency. A multi-layered simulant composed of granular soil and hard rock is built to test the adaptability of drilling and coring. To tackle complex drilling media, an intelligent drilling strategy based on online recognition is proposed to improve the adaptability of the sampling drill. The primary features of this research are the proposal of a scheme for drilling and coring a test-bed for validation on earth and the execution of drilling experiments in complex media.

Design and Test of the Semi-Automatic Test-Bed with Inclined Belt of Garlic Transplanting Machine

In order to verify the feasibility of semi-automatic garlic planter with inclined belt program and determine its reasonable operating parameters, the semi-automatic test-bed with inclined belt of garlic transplanting machine was designed, and the garlic box experiments were conducted. The angle of inclined belt on the test-bed and its running speed were adjustable. Single factor test results showed that the program of the semi-automatic garlic planter with inclined belt was feasible, and the angle of inclined belt and the test bed running speed affected the indicators. Orthogonal experiment results showed that the angle of inclined belt was the main factor affecting the test indicators. It is also found that the best angle was 30 degrees, while the most reasonable running speed was 0.75 Km/h.

基于依赖模型的REST接口测试用例生成方法研究

REST接口中普遍存在依赖关系,导致生成合理的接口调用序列与输入参数变得十分困难。现有的大多数方法只考虑了其中一种依赖关系,并需要人工执行繁杂的前置操作,生成的测试用例有效性仍然较低。针对以上问题,文中提出了一种基于依赖模型的测试用例生成方法。通过解析OpenAPI文档,该方法提取了接口内的操作间依赖关系与参数间依赖关系,并据此建立了两种依赖模型,从模型生成测试用例,最后从3方面确定测试预言。实验结果表明,该方法的输入度量覆盖率达到了100%,状态码类别、状态码、响应资源类型的覆盖率分别达到了100%,91.67%,83.33%,并能在限定时间内检出接口内部缺陷;与RESTler和RESTest相比,该方法的输出度量覆盖率最大提高了36%,触发了最多次的异常响应状态码,检测到接口异常响应的比例最大提高了10%。该方法为REST接口的测试用例生成问题提供了有价值的参考。

Study of the Effects of Lower Limb Muscle Strengthening Exercises on Hospitalized Pregnant Women on Bed Rest for Prevention of Miscarriage

Objective: Against a background of the two-child policy in China, the objective is to explore the effects of lower limb strengthening exercises on hospitalized pregnant women put on bed rest for prevention of miscarriage. Method: Sixty cases of pregnant women admitted to the Department of Obstetrics in one of the highest ranking hospitals in Guangzhou, China, during the period from November 2018 to December 2019 for the purpose of preventing miscarriage were selected. They were divided into an experimental group and a control group of 30 cases each. The control group was put under routine care while the intervention group conducted lower limb muscle strengthening exercise on top of the routine care. After the intervention, the conditions of lower limbs, the psychological states and the results of pregnancy for the two groups were compared. Results: After the intervention, the scores of the experimental group in anxiety, depression and postpartum depression were lower and leg circumferences were smaller compared to the control group. The difference is statistically significant (P < 0.05). The experimental group had longer gestation than the control group and was able to get out of bed earlier than the control group after delivery, with statistically significant difference (P < 0.05). Conclusion: Lower limb muscle strengthening exercises can effectively improve the physiological and psychological states of pregnant women hospitalized for prevention of miscarriage and promote their postpartum recovery.