A consecutive joint shear strength model considering the 3D roughness of real contact joint surface

A consecutive joint shear strength model for soft rock joints is proposed in this paper,which takes into account the degradation law of the actual contact three-dimensional(3D)roughness.The essence of the degradation of the maximum possible dilation angle is the degradation of the 3D average equivalent dip angle of the actual contact joint asperities.Firstly,models for calculating the maximum possible dilation angle at the initial and residual shear stress stages are proposed by analyzing the 3D joint morphology characteristics of the corresponding shear stages.Secondly,the variation law of the maximum possible dilation angle is quantified by studying the degradation law of the joint micro convex body.Based on the variation law of the maximum possible dilation angle,the maximum possible shear strength model is proposed.Furthermore,a method to calculate the shear stiffness degradation in the plastic stage is proposed.According to the maximum possible shear strength of rock joints,the shear stress-shear displacement prediction model of rock joints is obtained.The new model reveals that there is a close relationship between joint shear strength and actual contact joint roughness,and the degradation of shear strength after the peak is due to the degradation of actual contact joint roughness.

A rigid-flexible coupling finite element model of coupler for analyzing train instability behavior during collision

Rail vehicles generate huge longitudinal impact loads in collisions.If unreasonable matching exists between the compressive strength of the intermediate coupler and the structural strength of the car body,the risk of car body structure damage and train derailment will increase.Herein,a four-stage rigid-flexible coupling finite element model of the coupler is established considering the coupler buckling load.The influence of the coupler buckling load on the train longitudinal-vertical-hori-zontal buckling behavior was studied,and the mechanism of the train horizontal buckling instability in train collisions was revealed.Analysis results show that an intermediate coupler should be designed to ensure that the actual buckling load is less than the compressive load when the car body structure begins to deform plastically.The actual buckling load of the coupler and the asymmetry of the structural strength of the car body in the lateral direction are two important influencing factors for the lateral buckling of a train collision.If the strength of the two sides of the car body structure in the lateral direction is asymmetrical,the deformation on the weaker side will be larger,and the end of the car body will begin to deflect under the action of the coupler force,which in turn causes the train to undergo sawtooth buckling.

Changing the Air Parameters in the Cotton Pneumatic Transport Pipe

This scientific article examines the issue of changes in the density and speed of the airflow in the pipeline pneumatic conveying equipment used in ginneries, analyzes the causes of changes in the density and speed of air.

Evaluation of Actual Evapotranspiration and Crop Coefficient in Carrot by Remote Sensing Methodology Using Drainage and River Water to Overcome Reduced Water Availability

Searching for alternative methods for traditional irrigation is World trend at days due to a reduction in water and increased of drought due to climate changes therefore farmers need use modern methods of scheduling water and minimizing water losses while also increasing yield. To meet the future increasing demands water and food there is a need to utilize alternative methods to reduce evaporation, transpiration and deep percolation of water. Any countries use recycled water (drain and sewage) and desalination water from the sea or drains to irrigate crops plus computing actual crop evapotranspiration (ETc) so as to calculate the amount of water to apply to a crop. The paper aims to assess the actual evaporation and evaporation coefficient of carrots, by planting carrots in a field and the crop was exposed to several sources of water (DW and RW) and comparing ETc, Kc and production among plots of three sites (A, B and C). The study used two types of irrigation water (drain water (DW) and river water (RW)). The results were to monthly rate and accumulated actual evapotranspiration to C (irrigation by RW only) more than A (67% RW and 33% DW) and B (17% RW and 83% DW) via 7% and 58%, respectively. The yield to C more than A and B by 17% and 75%, respectively. In conclusion the use of DW can cause a reduction in crop consumptive of carrot crops also causes a reduction in yield, crop length, root length, root size, canopy of crop, number of leaves and biomass of the plant therefore, the drainage water needs to treated before irrigating crops And making use of it to irrigate the fields and fill the shortfall in the amount of water from the river. The drain water helped on filling the water shortage due to climate changes and giving production of carrot crop but less than river water.

Forestry ecological footprint in China during 1973–2003

The ecological footprint （EF） model has received much attention as an assessment indicator for sustainable development in recent years. Firstly, the temporal changes of domestic timber production, imports and exports in China were analyzed from 1973 to 2003, the analysis results showed an apparent fluctuation in timber production during 1973-1995 but a decreasing trend during 1995-2002, an increasing trend in timber imports since 1995 especially after the implementation of the Natural Forest Protection Project （NFPP）, an decreasing trend year by year in timber exports since 1995. Secondly, this paper presented a time series analysis of actual forest area demand in the sustainable yield and production approach in China from 1973 to 2003, which includes both import and export forest area demand. The results showed the actual forest area demand simulated from the sustainable yield approach was slightly higher than that from the production approach during 1978-1988 and a little lower during 1989-2003; however, the actual forest area demands simulated by these two model approaches were larger than calculations that expressed in conventional forest EF. Meanwhile, the results indicated the forestry development in China during 1978-1988 was unsustainable due to overexploitation of forest stocking volumes, and China＇s forestry moved toward sustainable development since 1989 because forest resources are exploited at lower rates than they are regenerated. However, compared to forestry developed countries, the forestry development capacity in China is still lower. Finally, based on the model results we analyzed the relationships between forestry EF and the key policies, including trade policy, economic policy and forest conservation programs. In addition, several suggestions about reducing forestry EF and enhancing sustainable forestry development in China are given.

The Actuality and Prospect of Meteorological Service Technology for Solar Greenhouse

The solar greenhouse's construction and its demand on meteorological service in the process of production management in China were analyzed,and the current situation of meteorological service on it was summarized.Combined with the trend of related technology,the future development of solar greenhouse meteorological service was prospected.

Evaluation of Tourist's Satisfaction Degree of Dongda Hot Spring Resort Area in Xi'an City

Tourist's satisfaction degree is one of the important indexes to evaluate the service quality of scenic spot.Taking Xi'an Dongda Hot Spring Resort Area for an example,with the expectation difference theory and customers' satisfaction evaluation model as the theoretical basis of the research,the overall satisfaction degree of tourists to hot spring resort area,and the actual sensation accomplishments and the expectation difference of each service index were analyzed by using regression analysis and paired sample t test method.The results showed:① The overall satisfaction degree of tourists to the resort area was higher.There were remarkable correlation among three variables:the sensation value,the overall satisfaction degree,and the tourist's loyalty degree;② Generally,the sensation actual accomplishments of 15 service appraisal factors were higher than the expectation value.According to the characteristics,these 15 service appraisal factors were divided into 5 groups.Some unsatisfactory aspects were found out,and the corrective measures were put forward.

Application of Farming Culture in the Construction of Eco-Park —A Case Study of Baiyunzhai Demonstration Eco-park in Chongqing City

Definitions and features of eco-park and theme park were introduced as well as their differences, it was proposed that by applying cultural themes suited to regional ecological resources in the construction of eco-park, the eco-park could achieve not only desired ecological benefits, but also social and economic benefits, and the optimal comprehensive benefits. Design of Baiyunzhai Demonstration Eco-park was taken for an example, integration of eco-park and farming culture was confirmed as the nature, principles of "adaptation to actual conditions, amended protection and construction of plant system" proposed, three functional areas of "Colorful Forest Belt, Yiyun Health Maintenance Zone, Lakefront Meditation Zone" are given on the basis of actual terrains, planning highlights and desired landscape effects expounded to promote the value of regional cultures in Chongqing by building Baiyunzhai Eco-park.

高考英语模拟练习(中)

第三部分:阅读理解(共20小题) 阅读下列短文,从每题所给的四个选项中,选出最佳选项。 A Fatigue(疲劳)can actually be considered akind of poisoning.When a muscle(肌肉)in ourbody works,it produces lactic acid(乳酸).If weremove the lactic acid from a tired muscle,it willbe able to start working again at once.

《英美文学选读》辅导(13)

Ⅰ.文学常识1.Calvinism (加尔文主义) -It is the theological system of John Calvin. Its key principle is that God, not man, is central and supreme. Hence scripture is the source of doctrine.2. original sin (原罪)-In Christian theology, it is the state of sinfulness in which all mankind

Integration system research and development for three-dimensional laser scanning information visualization in goaf

An integration processing system of three-dimensional laser scanning information visualization in goaf was developed. It is provided with multiple functions, such as laser scanning information management for goaf, cloud data de-noising optimization, construction, display and operation of three-dimensional model, model editing, profile generation, calculation of goaf volume and roof area, Boolean calculation among models and interaction with the third party soft ware. Concerning this system with a concise interface, plentiful data input/output interfaces, it is featured with high integration, simple and convenient operations of applications. According to practice, in addition to being well-adapted, this system is favorably reliable and stable.

四、六级难句攻关(46)

1.Is the belief that marriage is between a man and a woman—until recently common even in liberal circles—now presumed so bigoted as to deserve no consideration,even when the exercise of this belief does not actually keep gays from marrying？（Washington News,Feb.24,2014）翻译：婚姻是男女之间的结合,这种观念直到最近就算在思想开明的圈子里都很常见。即便这种观念并不妨碍同性恋者结婚,如今难道也被认为古板而不值得考虑吗？

考研翻译能力训练(85) 脱欧的悲剧

从难以想象到覆水难收,这一切的发展是多么迅速。一年前几乎没有人能想到,众多喜欢抱怨欧盟（规章制度愚蠢、预算庞大、充斥浮夸官僚主义）的英国人,竟然真的会投票退出这个购买其近一半出口物的国家俱乐部。然而,到了6月24日凌晨,选民们显然不顾经济学家、盟友和本国政府的警告,在作为欧盟成员40多年后，即将大胆迈入未卜的前程。

应对英语四级听力选择题的10大原则

对于非英语专业的大学生而言,大学英语四级考试的阅读和写作部分不难过关,能否顺利通过英语四级往往取决于听力是否及格。英语四级听力部分的分值占总分的35%,其中英语听力选择题所占比例为25%。下面笔者将从听前预读选项、听时把握重点和听后答题要点三个方面来介绍解答听力选择题的10大原则,希望对考生答题有所帮助。听前预读选项由于英语四级考试的命题人是在知道正确答案的基础上来编写其他干扰项的,所以这些干扰项或多或少会和正确答案有关联。因此,考生在听前预读选项时。

《电大英语》第三册模拟试题

Ⅲ.每道题下有A,B,C和D四个选项。根据句子的意思,其中只有一个是正确的。将正确的选项选出,并将答案写在答题纸的相应题号旁。

The Influence of Second-Language Self-Orientation on Learning Motivation of Medium Level EFL Proficiency

EFL motivation is a hot research field of second language learners.In recent years,many researchers have focused on Dornyei’s second language self-system as a theoretical framework.The purpose of this study is to examine the predictive power of self-orientation of college medium level English learners to EFL learners’motivation,and to find ways to enhance their motivation and EFL proficiency.The subject of this paper is a medium level students of an ordinary college.Using linear regression analysis to collect data through questionnaires,it is found that the self-orientation of the subjects can explain the predictive effect on the actu⁃al learning behavior is not ideal.Ideal L2 self and L2 self-confidence are insufficient,and corresponding learning strategies are lacking,which limits self-directed ability to predict L2 motivation.

Actual evapotranspiration of subalpine meadows in the Qilian Mountains, Northwest China

As a main component in water balance,evapotranspiration(ET)is of great importance for water saving,especially in arid and semi-arid areas.In this study,the FAO(Food and Agriculture Organization)Penman-Monteith model was used to estimate the magnitude and temporal dynamics of reference evapotranspiration(ET0)in 2014 in subalpine meadows of the Qilian Mountains,Northwest China.Meanwhile,actual ET(ETc)was also investigated by the eddy covariance(EC)system.Results indicated that ETc estimated by the EC System was 583 mm,lower than ET0(923 mm)estimated by the FAO Penman-Monteith model in 2014.Moreover,ET0 began to increase in March and reached the peak value in August and then declined in September,however,ETc began to increase from April and reached the peak value in July,and then declined in August.Total ETc and ET0 values during the growing season(from May to September)were 441 and 666 mm,respectively,which accounted for 75.73%of annual cumulative ETc and 72.34%of annual cumulative ET0,respectively.A crop coefficient(kc)was also estimated for calculating the ETc,and average value of kc during the growing season was 0.81(ranging from 0.45 to 1.16).Air temperature(Ta),wind speed(u),net radiation(Rn)and soil temperature(Ts)at the depth of 5 cm and aboveground biomass were critical factors for affecting kc,furthermore,a daily empirical kc equation including these main driving factors was developed.Our result demonstrated that the ETc value estimated by the data of kc and ET0 was validated and consistent with the growing season data in 2015 and 2016.

Comparison of pan evaporation and actual evaporation estimated by land surface model in Xinjiang from 1960 to 2005

Pan evaporation,an indictor of potential evaporation,has decreased during the last several decades in many parts of the world;the trend is contrary to the expectation that the increase of actual evaporation will accompany global warming,known as the pan evaporation paradox.What is the essential relationship between pan evaporation and actual evaporation? This is still an uncertain problem.In this paper,the trends of pan evaporation and actual evaporation are investigated using observational data and observation-constrained simulation results using NCAR Community Land Model(CLM) in Xinjiang from 1960 to 2005.Our analysis suggests that the decreasing trend of annual pan evaporation accompanies the increasing trend of annual actual evaporation,the tendencies of them both have statistical significance(at 99% level and at 95% level,respectively).We also find that there is the same turning point in precipitation,pan evaporation and actual evaporation of 1986,and either before the point or after,pan evaporation has inverse trend comparing with actual evaporation and precipitation.The above analysis indicates that pan evaporation and actual evaporation have complementary relationship.These results support the issue of evaporation paradox described by Brutsaert and Parlange(1998) and suggest that decrease of pan evaporation indicates an increase of actual evaporation in Xinjiang in the past half century.The correlation analysis shows that diurnal temperature range(DTR),wind speed,low cloud cover and precipitation are the most likely driving forces for the reduced pan evaporation and the ascending actual evaporation.

Status quo and development trend of lost foam casting technology

Lost foam casting(LFC)technology has been widely applied to cast iron and cast steel.However,the development of LFC for Al and Mg alloys was relatively slower than that for cast iron and cast steel.The application of LFC to Al and Mg alloys needs more effort,especially in China.In this paper,the development history of LFC is reviewed,and the application situations of LFC to Al and Mg alloys are mainly discussed.Meanwhile,the key problems of LFC for Al and Mg alloys are also pointed out.Finally,the prospects for LFC technology are discussed,and some special new LFC technologies are introduced for casting Al and Mg alloys.In future,the development trends of green LFC technology mainly focus on the special new LFC methods,metal material,coating,heat treatment,new foam materials as well as purification technology of tail gas,etc.

Estimation of water balance in the source region of the Yellow River based on GRACE satellite data

Water storage has important significance for understanding water cycles of global and local domains and for monitoring climate and environmental changes. As a key variable in hydrology, water storage change represents the sum of precipitation, evaporation, surface runoff, soil water and groundwater exchanges. Water storage change data during the period of 2003-2008 for the source region of the Yellow River were collected from Gravity Recovery and Climate Experiment （GRACE） satellite data. The monthly actual evaporation was estimated according to the water balance equation. The simulated actual evaporation was significantly consistent and correlative with not only the observed pan （20 cm） data, but also the simulated results of the version 2 of Simple Biosphere model. The average annual evaporation of the Tangnaihai Basin was 506.4 mm, where evaporation in spring, summer, autumn and winter was 130.9 mm, 275.2 mm, 74.3 mm and 26.1 mm, and accounted for 25.8%, 54.3%, 14.7% and 5.2% of the average annual evaporation, respectively, The precipitation increased slightly and the actual evaporation showed an obvious decrease. The water storage change of the source region of the Yellow River displayed an increase of 0.51 mm per month from 2003 to 2008, which indicated that the storage capacity has significantly increased, probably caused by the degradation of permafrost and the increase of the thickness of active layers. The decline of actual evaporation and the increase of water storage capacity resulted in the increase of river runoff.