bluuebunny/crossref_metadata_2025 huggingface dataset:
Combined Effect of Load and Water Environment on Creep Behaviours of Red Sandstone
Authors: Yu Chaoyun , Tang Chunan
Published: June 2019

Creep experiment was conducted on specimens submerged in water to know the combined effect of load and water on mechanical behaviour of red sandstone. Compared with saturated and dry specimen with the sealed surface, results show that the steady-state creep strain rate of submerged specimen is the highest, whereas, the corresponding long-term strength is the smallest. Creep cracks initiation and propagation make it possible for water in the environment to migrate into the tip of new cracks, which intensifies the stress corrosion effect of water. This is the effect mechanism of a combined action of load and water on the creep behaviour of red sandstone. The presented experimental results are beneficial for monitoring and assessing the long-term stability and safety of rock engineering.
Experimental Study of Pervious Concrete Using Recycled Coarse Aggregate
Authors: Zhang Weidong , Gao Yanan
Published: June 2019

The project aims at study the effect of water-cement ratio and the replacement ratio of recycled coarse aggregate (RCA) on the physical and mechanical properties of pervious concrete and the correlation between these properties. The research methodology is to replace natural coarse aggregate (NCA) with RCA at four replacement levels of 10, 20, 30 and 40 % and adjust water-cement ratios of 0.25 and 0.30. The total void content, effective void content, cubic compressive strength, splitting tensile strength, water permeability, and abrasion resistance of pervious concrete were tested. The results show that with the increasing of w/c ratio or replacement ratio of RCA, void content and permeability coefficient of pervious concrete increase in a certain degree, but cubic compressive strength, splitting tensile strength and abrasion resistance decrease. Data analysis shows that there are good correlations between relevant performance indicators.
An Improved Damage Mechanics Method for Solving Three Dimensional Crack Problems of Concrete
Authors: Yun Kumchol , Wang Zhenqing
Published: June 2019

In this paper, a damage mechanical model is improved to simulate the three-dimensional (3D) mixed mode cracking process of quasi-brittle material such as concrete. The cracking and crack propagating in an element is reflected in the model by controlling the degraded stiffness matrix and the dissipated energy. The local tracking algorithm (LTA) is employed to preselect the element that will belong to the crack path to be damaged. The local tracking algorithm is extended to 3D by analyzing and overcoming defects in the previous 3D LTAs. The present LTA has very low computational cost and this fact is proved by comparison with well-known global tracking algorithm. The numerical results from the novel damage model added 3D local tracking algorithm show good agreement with the results of the previous researches, demonstrating the superior performance of the approach in predicting crack propagation and fracture strength.
Experimental Measurement of Volume Changes on Cement Concrete Depending on the Subsoil
Authors: Kropacek M. , Cajka R.
Published: June 2019

The paper describes experimental measurement of volume changes of cement concrete elements depending on the subsoil. Volume changes of cement concrete (including shrinkage and swelling) are theoretically known and at present there are many calculation models to determine the final shrinkage at the time of the design of the concrete or construction. The subsoil beneath the concrete structure has a significant effect on the volume changes of the concrete, and this behaviour must be considered when designing. However, the calculation models do not consider the influence of the subsoil and friction effects. The experiment described in the article includes the behaviour of different concretes on differently defined subsoils. At the defined input conditions, volume changes have been measured over the long term in different climatic conditions. The result of the experiment is the values of volume changes, depending on the concrete-subsoil interaction.
Breaking of Key Layers and Surface Subsidence in the Loess Mountainous Areas
Authors: Lv Ke , Wang Jinan
Published: June 2019

During the process of mining subsidence, the thick loess layer will have certain cohesion, tensile strength and flexural strength. Therefore, the thick loess layer may have a significant impact on the overburden load of the mining area, which further affects the fracture and surface subsidence of the overlying strata on the working surface. The calculation model was constructed based on the mining geological conditions of the loess mountainous area in Jinhe Coal Mine of Gansu Province. The mining surface and process were simulated by FLAC3D, and the load effect of loess layer thickness on its lower strata and its key layers was analyzed. The results show that the surface loess layer is mainly caused by tensile failure, and the other rock layers are mostly shear failure. The key layer has obvious control effect on surface settlement, and its fracture can lead to significant settlement on the surface. Under the condition of thick loess layer, the initial breaking distance of the key layer is larger than that of the critical mining length. The results show that the equivalent load coefficient of the loess layer is obtained and applied to the calculation of the fracture distance, which can obtain more realistic parameters.
Numerical Simulation Parametric Studies on Concrete-Filled Steel Tubular Columns
Authors: Zhao Lidong , Cao Wanlin , Ye Taopin
Published: June 2019

The finite element(FE) software is used to simulate concrete-filled steel tubular(CFST) columns. Based on the existing experimental data, the model is verified. The parameters studied include axial load ratio and shear span ratio, and the difference of seismic performance between circular CFST column and square CFST column under the condition of equal steel ratio is compared. The results show that with the decrease of axial load ratio, the hysteretic curve is plumper and the seismic performance is more stable. With the decrease of shear span ratio, the horizontal bearing capacity of the specimen increased significantly, but the cumulative damage effect was more significant. The simulation results also show that when the steel ratio is identical for circular and square CFST columns, the circular CFST column has superior seismic performance.
Design and Implementation of 3D Urban Underground Pipe Network System
Authors: Pang Liyang , Lan Guiwen , Tao Yanyu
Published: June 2019

For the sophisticated spatial relationships of the urban underground pipeline networks, 3D visualization technology has become widely used for management and maintenance purposes of these types of underground utilities. With the increasing number of pipeline incidents, there is an urgent need for effective solutions for improving the management of urban underground pipe networks. In this paper, through a thorough analysis of the pipeline network management, a 3D urban underground pipe network system (3D UUPNS) was designed and implemented by using SuperMap.Net. The 3D models of the pipeline network and ground buildings are rendered by using SuperMap RealSpace Library, with 3D models of ground buildings being cached into OSGB format. Some analysis functions such as excavation analysis and section analysis, have been developed to support the management and operations of underground pipelines.
Influence of Mineral Admixture in CSA Cement on Chloride Binding Capacity
Authors: Jiang Xuelei , Zhong Zhenhao , Liu Wei
Published: June 2019

Increasing chloride binding capacity of hardened cement paste is an effective method in reducing corrosion risk of reinforcement in concrete structures exposed to marine environment and guarantee its designed service life. Compared with traditional Portland Cement, Calcium Sulfoaluminate Cement (CSA) has been proved for its better chloride binding capacity in practice. However, in order to save cement consumption and reduce environmental pollution, it is important to investigate the influence of mineral admixture on the Cl− binding capacity of CSA cement. Based on this background, authors of this paper studied influence of key parameters within CSA-Cl− mix proportion, i.e. mixtures like Calcium carbonate (C), Slag (S), Fly ash (F) and Metakaolin (M) and use of gypsum and studied its effect on the chloride binding capacity. Meanwhile, the Cl− binding mechanism was also explored by means of XRD and TG. From the results obtained, it can be concluded that the use of gypsum led to an increase in ettringite, which caused a severe drop in chloride binding capacity; the addition of mixtures led to an increase in chloride binding capacity.
Experimental Study on Mechanical Properties and Water Permeability about 107 Glue for Slag Permeable Brick
Authors: Chen Xiaoxia , Fan Qingxian
Published: June 2019

The main materials of the slag permeable brick were blast furnace slag, the waste generated in metallurgical industry, cement, and 107 glue as well, which were used in architecture as main cementitious material. The influence of 107 glue on the mechanical properties and water permeability of slag permeable brick were analyzed, and the formula and technological parameters of permeable brick were optimized by the method of contrast experiment. The permeability coefficient was the best when the compressive strength was satisfied, and the optimal mix ratio was also determined.
On Dynamic Constitutive Model of Granite Under Impact Loading: Effect of Damage on Dynamic Strength
Authors: Liang Shufeng , Ling Tianlong , Liu Dianshu , Li Shenglin
Published: June 2019

Dynamic mechanical properties of granite were tested by a split Hopkinson pressure bar system at constant strain rates. The experimental results show that granite behaves linearly elastic at the initial loading stage, followed by a significant plastic deformation after yielding, and yield strength, ultimate strength and elastic modulus are all rate dependent. On this basis, the simplified Zhu-Wang-Tang (ZWT) constitutive model is applied in this paper, assuming elastic and high frequency viscoelastic elements only. The damage evaluation equation is introduced to the simplified ZWT model to investigate the effect of damage on the dynamic strength of granite due to impact load. Finally, the proposed model is applied to fit the experimental data. It is known that the fitted stress-strain curves at different strain rates are in agreement with the experimental ones. Compared with experimental data, the error of yield stress, peak stress and corresponding strain obtained by fitting method are all not larger than 10%. This demonstrates that the proposed dynamic constitutive model can accurately describe the dynamic mechanical properties of granite under impact loading.
Fine Tailings Heap High Levels of Radiation Seepage Drainage Wells Application
Authors: Zeng Kaihua , Dai Hongtao , Yao Hui
Published: June 2019

Jiangxi Xingan Xinheng mining tailings, the tailings discharge chute fracture accident, backfilling materials caused by leakage. After emergency measures for drainage tunnel mouth sealed, to make the library lost only drainage channels, the backfilling is fine drainage is poor, saturation line rising, pose a safety hazard. In this paper, Xinheng mining tailings as an example, put forward the suitable level of tailings backfilling fine particle size, small permeability coefficient e radiation well engineering measures and construction technology, let the radiation well drainage and horizontal tube drainage measures etc, for drainage effect comparison and analysis, the results show that, using the radiation well drainage measures more outstanding. Short construction time limit for a project, drainage effect is good, can provide the basis for other similar tailings e measures adopted and the reference.
Elastic Modulus Reduction Method Based Ultimate Bearing Capacity Analysis of CFST Truss Arch
Authors: Zheng Jian , Wang Jianjun , Yang Lufeng , Xie Weiwei , Zhao Yufeng
Published: June 2019

In order to evaluate the application of elastic modulus reduction method on the ultimate bearing capacity analysis of CFST truss arch, the elastic modulus reduction method was compared with the test data and the increment nonlinear finite element method. Firstly, the element bearing ratio was defined according to the homogeneous generalized yield function, and the principle of deformation energy conservation was adopted to derive the elastic modulus adjustment strategy, based on which the modulus reduction method was developed for the ultimate bearing capacity analysis of CFST structures. Then, combined with the incorporated strength capacity technique, the section strength was modified to consider the structural constant load effect. Finally, the ultimate bearing capacity of a CFST truss girder and 136m span truss arch was obtained on the basis of the proposed method, and the results were compared with the test data and the incremental nonlinear finite element method. The results show that the elastic modulus reduction method can achieve high calculation accuracy and wide application for the ultimate bearing capacity analysis of CFST truss arch.
Calculation Method of Flexural Capacity of Composite Beam in Negative Moment Area after Corrosion of Interfacial Bolt
Authors: Xu Bo , Zhu Weiqing , Shang Yang
Published: June 2019

In order to quantitatively calculate the stud shear bearing capacity after corrosion, this paper used the stud shear bearing capacity factor after corrosion to represent the stud corrosion degradation effects, and based on the analysis of the reasons for its reduction, the product between stud effective section area after corrosion and stud tensile strength was proposed to calculate the shear capacity coefficient. At the same time, based on the assumption of plasticity theory, the simplified calculation formula of the composite beam flexural capacity under hogging moment was derived by simplifying the sum of the flexural capacity of the steel beam, the longitudinal reinforcement in the concrete plate and the stud. The effect of interface stud corrosion for the flexural bearing capacity of steel-composite composite beam was considered by multiplying the stud Shear capacity coefficient after its corrosion, and the experimental data of 11 beams were combined to verify. The results showed that the calculated results of this method were highly consistent with the experimental results in the literature. The calculated results were on average less than 2% of the experimental results, and the coefficient of variation was only 0.01. The calculated results of the formula were consistent with the results of theoretical analysis in the literature, and the calculation method was simple and convenient. It can be evaluated for the composite beam flexural capacity under hogging moment with corroded shear studs
Contrastive Analysis of Indoor Model Test and Numerical Test on Pull-Out Failure of Fully-Embedded Anti-Slide Pile
Authors: Qiu Peng
Published: June 2019

In this paper, the strain of steel bar, concrete of pile body, displacement of pile top and earth pressure around piles are monitored under pull-out failure mode of fully-embedded anti-slide piles, and the stress mechanism of fully-embedded anti-slide piles is studied by numerical simulation. The results show that when the anchorage depth of anti-slide piles is insufficient, the rigid rotation of piles is dominant, and the strain change of pile body is not obvious. Through the analysis of the working parameters of the anti-slide pile, it is concluded that both sides of the loading point of the anti-slide pile are subjected to an upward pulling force, which makes the anti-slide pile tend to pull out. Through the simulation analysis of the model test, it can be concluded that with the increase of load, the sliding up-welling zone behind the pile tends to expand, and the pile body is subjected to a “pull-out” effect of the surrounding sand.
Study on the Parameters of Roadside Support after the Cantilever Beam of the Basic Roof with Height of Fracture Zone Cut by Deep-Hole Blasting
Authors: Hu Tao , Hou Gongyu , Li Zhuhe , Chen Jianpeng
Published: June 2019

In order to determine the reasonable parameters of roadside support, based on the analysis of the law of surrounding rock activity in gob-side retaining roadway, it is proposed that the relationship between different parameters of roadside support wall and its supporting resistance is calculated and analyzed by using the improved mechanical model after deep-hole blasting roof cutting and improving the external mechanical environment of surrounding rock then. The mechanical equation for calculating the width and strength of supporting wall near roadway is derived. The analytical solution of width and strength value of roadside support under roof cutting condition is obtained, and field application is carried out in 3207 working face of Nanyang Coal Mine. The results show that it is feasible to set the height of the upper-side fissure zone of the goaf beside the roadway as the height of the cutting roof; it is reasonable to calculate the height of the cut roof as the height of the static block; the formula of the width with a certain strength of the roadway support wall obtained in this paper and the redundant safety factor of the parameters of the roadway support wall tried to be adopted are effective. Finally, after improving the external mechanical environment of retained roadway surrounding rock, reasonable parameters of roadside support are the guarantee to ensure the stability and integrity of retained roadway structure along goaf.
An Improved Seismic Damage Assessment Model for Buildings Based on Parallel Algorithms
Authors: Feng Biao , Lan Riqing , Yu Shizhuo
Published: June 2019

The efficiency of post-quake emergency management depends heavily on the speed of seismic damage assessment software, which depends on the evaluation algorithm essentially. Traditional seismic damage assessment models based on sequence algorithms usually need tens of minutes to get visualized results. More efficient computing models for seismic damage assessment are demanded urgently. General parallel evaluation algorithm based on GPU computing framework was investigated by the authors, and an improved seismic damage assessment model for buildings was proposed in this paper. We designed a three-level parallel scheme to accelerate the computing and visualization. At the top level, the earthquake area is divided into smaller regions, such as cities or counties. At the middle level, fundamental geographic data for each region is split into layers by features. At the bottom level, buildings are grouped into several types, which can be processed by GPU cores simultaneously. The developed model can estimate and analyze the seismic damage of buildings and the spatial distribution of victims in earthquake region more rapidly than traditional models.
The Analysis of Interface Normal Stress of Short Column of Square Concrete-Filled Steel Tube with Axial Compression
Authors: Zhang Zhengqi , Liu Yongjian , Zhang Zhiheng , Cheng Gao
Published: June 2019

The interface normal stress reflects the interaction between the steel tube and the concrete in the tube, which is helpful to distinguish the time and size that begin to appear confinement effect of the concrete filled steel tube. The typical CFST members in engineering applications may be loaded such as loading through the whole cross section, loading through steel alone and loading through concrete alone, etc. Establishing nonlinear finite element model to analyse the interface normal stress between steel and concrete along the section width, short column height and with the change of axial compressive load, the results show that the different loading mode of CFST column interface normal stress along the width of the cross section showed a “trough” distribution, but the value is different, sorted by size in descending order is loading through concrete alone, loading through the whole cross section, loading through concrete alone. When steel tube and concrete are subjected to loads, the effective length of steel tube confined concrete is about 0.55 times the width of the section, and the normal stress of the interface is almost 0 in the unconstrained area after 0.5 times of the ultimate load.
Construction Monitoring and Numerical Simulation Analysis of the Yangwujian Soft Rock Tunnel
Authors: Zeng Kaihua , Yu Jia , Li Xuejun
Published: June 2019

Tunnel construction monitoring plays a key role in excavation construction of soft surrounding rock tunnel, it can be accurately judged stability of surrounding rock, its provide more priority information to design and construction. This paper adopts to construction of New Austrian Tunnel-ling Method (NATM), by strengthening the supporting and actual measurement on the spot, obtained displacement curve above vault settlement and clearance convergence. Selection parameter of supporting structure property by using Midas-GTS finite element analysis software, as well it has obtained both upper guide and down guide clearance convergence displacement-excavation step curve and valut settlement-excavation step curve. It’s found that: the faster stage of changing velocity is the first 10 days; the optimal execution time of the secondary lining is that the tunnel was excavated 30 days. It’s almost anastomosis both numerical simulation analysis and actual monitoring, it is better confirmed correctnass to establish the tunnel model, which provide reference for design and construction.
Numerical Calculation of Instability of Tunnel Surrounding Rock Based on Elastic Hole Theory
Authors: Yang Haobo
Published: June 2019

The instability and unloading of surrounding rock structure in tunnel under TBM construction condition can easily induce large-scale rock caving in heading face, which seriously restricts safe and efficient tunneling. Aiming at the instability problem of surrounding rock structure of tunnel constructed by TBM, four types of slope induced by excavation disturbance are summarized systematically based on elastic hole theory, and the instability mechanism of roof structure and surrounding rock of tunnel is analyzed; the instability mechanism and catastrophic characteristics of surrounding rock structure of tunnel are analyzed by FLAC3D finite element numerical calculation software, and the roof transportation of tunnel after supporting is carried out. The amount of movement is greatly reduced and the overall failure degree of overlying strata is slowed down. The results show that the roof is prone to structural instability under the influence of tunneling disturbance. Tunnel support can effectively hinder the movement of overlying rock roof and floor, alleviate the probability of rock mass catastrophe, effectively control the dynamic disasters, and achieve safe tunneling.
Simulation Analysis of Frame Structure Acceleration Response in Subway Buried Blasting
Authors: Guo Weina , Bi Weiguo , Ren Sijian
Published: June 2019

In order to analyze the response of the acceleration peak in different directions of frame structure to the variation of blasting distance and layer height in the shallow blasting. Based on the shallow blasting of subway, this paper uses ANSYS/LS-DYNA finite element analysis software to construct the framework structure calculation model and simulate the acceleration peak. The results show that the acceleration peak of the frame structure appears between the vertical three-layer and four-floor, and the longitudinal acceleration peak is one order of magnitude larger than the lateral direction. The acceleration peak and the blasting distance are negatively correlated, which is positively correlated with the layer height. Therefore, before the blasting construction, the seismic strengthening of the thin layer of the intermediate layer of the multi-layer frame which is close to the source of the explosion must be carried out.
Comparative Analysis of Performance of Porous Asphalt Pavement and SMA Pavement Based on Deck Pavement Structure
Authors: Yang Zhihao , Xu Bin , Cao Dongwei
Published: June 2019

Viaducts are more and more widely used in China. How to ensure the safety of the bridge deck has become a hot issue of concern? Based on the above problems, the application of porous asphalt pavement in bridge deck pavement is also increasing. Based on the porous asphalt pavement project of Shijiazhuang City Ring Road (West Second Ring of Heping West Road), the performance differences between porous asphalt pavement and stone matrix asphalt pavement were studied. By comparing the gradation characteristics and performance of porous asphalt mixture and stone matrix asphalt mixture, the advantages and disadvantages of the two mixtures in road performance were analyzed. At the same time, we carried out on-site braking test, noise test and long-term temperature monitoring on two types of pavement. By comparing the test results, we thought that porous asphalt pavement could reduce the braking distance by up to 7 m in mid-to heavy rain weather, and porous asphalt pavement could reduce 2-6 dB noise, Porous asphalt pavement has better cooling effect than stone matrix asphalt pavement, and the higher the external temperature was, the better the cooling effect of porous asphalt pavement was, and it could reduce 6-8°C in summer. Through the test comparison, we draw the conclusion that the pavement performance of porous asphalt pavement is better than that of stone asphalt pavement.
Research on the Quality Control Technology of Dam Shoulder Groove Project of Wudongde Hydropower Station
Authors: Ming Ming , Liu Yang
Published: June 2019

The shoulder groove project of Wudongde dam is a key program of the entire Wudongde Hydropower Project. The slope of the dam project is centered on the dam shoulder groove, where the upstream is the upstream shoulder and the power station intake, and the downstream is the downstream shoulder, plunge pool, second dam and downstream revetment. Therein, the excavation quality of the dam shoulder groove directly affects the long-term safety of the dam operation. The dam shoulder groove excavation elevation is 988m-718m, with the excavation height of about 270m, the excavation width of 18.32-51.42m, and excavation slope ratio of 1:0.21-1:9.2. The slope changes from steepness to slow, and there is no horse track set in the middle. Since the excavation quality directly affects the long-term safety of the dam operation, this paper deeply analyzes the influence factors of the relevant quality control requirements such as over-under-excavation, flatness, half-hole rate and blasting depth of the dam shoulder groove project of Wudongde Hydropower Station through integration and modularization of its key processes. This paper has a certain practical significance for the formation of the theoretical system and practical foundation of quality control technology for abutment trough of high slope dam of large hydropower station.
Sustainability-Based Construction of the Restoration Projects for the Guguan Hydropower Station
Authors: Liu Taiyi , Chen Pohan , Chou Nelson N.S.
Published: June 2019

In Taiwan, the Dajia River is one of the most important rivers that provides hydroelectric energy. A couple of well-operated hydropower stations have been placed in different sections of this river for several decades. The 921 earthquake that hit central Taiwan in 2000 and Typhoon Toraji that attacked this area in 2001 caused severe damage to almost all hydropower stations. To continue to provide sufficient power for the public, the restoration of these power stations is necessary. Taiwan Power Company (Taipower) was responsible for the restoration projects. The Guguan hydropower station, which could provide 212.8 MW power, is one of the most damaged power stations. The Guguan power station restoration project, executed by the New Asia Construction and Development Corporation (NA Corp.), was started in April 2002. During the project, a series of typhoons and heavy storms attacked central Taiwan between 2004 and 2007 (especially Typhoon Mindulle in 2004). Consequently, the restoration work was greatly hindered; in particular, there was massive groundwater leakage from all external walls of the tunnel and powerhouse structures. The maximum leakage of groundwater was up to 84 tons/min. This situation not only caused extreme difficulty that interrupted the restoration work but also made the construction site a dangerous environment to continue restoration or future operation. In addition, the construction facilities were damaged, resulting in suspension of the restoration work. For safety construction of the restoration work, a series of temporary protection structures/platforms and a large quantity of grouting work had been performed. This power station was well restored and engaged in commercial operation in October 2008. In this paper, the detailed working procedures of the safety construction methods are presented.
Time Delay Estimation via Correlation in the Non-Synchronous Sensor Network by the Internet of Things
Authors: Chen Ziyang , Xue Songtao , Xie Liyu
Published: June 2019

This paper is concerned with the elimination of time delay among data from different channels sampled by the sensor network from the Internet of things (IoT), especially the wireless sensor network (WSN) in Structural Health Monitoring (SHM). In this paper, a technique using correlation has been proposed and moving window plays an important role in this algorithm. Obtaining the correlation coefficient at each point, use interpolation function to fit a curve so that the sub-sampling-interval part of time delay can be calculated, which is enlightened by sub-pixel deformation algorithm from Digital Image Correlation (DIC). The length of each segmentation and the choice of interpolation function will affect the computational efficiency and the quality of result, so they should be carefully confirmed. Finally, a numerical experiment has been conducted to verify this method and analysis the error of this method, and gives out a satisfactory consequence.
Repairs and Construction Technique of Neoteric Buildings in China: A Case Study of the Building of College of Engineering in Wuhan University
Authors: Chen Yiwen , Zeng Qing , Cai Huiwang , Liu Zhi
Published: June 2019

Based on the principles of protection and repair of cultural relic buildings, this paper takes the repair project of the Building of College of Engineering in Wuhan University as an example, analyzes the architectural characteristics and construction difficulties, lays stress on scientific analysis methods, and determines the repair method combining modern technology with traditional technology. In the process of rehabilitation and construction, the principles of “not changing the original state of cultural relics” and “minimal intervention” are followed, and the requirements of facilities and functions are improved appropriately, so as to prolong the life span of the building and give full play to its use value.
Study on Promoting General Contracting Construction in China Referencing IPD Principles
Authors: Zhang Yinglong , Hu Hao , Xu Feng , Tian Yu
Published: June 2019

Integration Project Delivery (IPD) brings innovation to the project management process with the concept of “integration”, and forms a relatively rich IPD principles system, which can provide reference for the development of General Contracting construction. In this paper, IOS Management System theory was used to analyze the key issues in the management Idea/Ideology, Operation/Organization, and Stratagem/Strategy of the General Contracting construction. It was concluded that the rights and responsibilities of the project general contractor should be emphasized, the contract organization mode of the parties involved in the General Contracting project should be well constructed, and highlights for signing the project general contract should be proposed. Focusing on the above three aspects, the authors sorted out and analyzed the related IPD principles, then put forward specific proposals to promote the development of the General Contracting construction in China under the guidance of “management and technology integration”, “organization integration” and “contract integration”.
Numerical Simulation of Dynamic Analysis of Glacier Under Seismic Loading Based on Combined Finite-Discrete Method
Authors: Su Y. , Liu E.l.
Published: June 2019

The dynamic analysis of the Laohugou No.12 Glacier of Qilian Mountain under given seismic loading effect is analyzed by using combined finite-discrete element method (FDEM). The necessary ice parameters for FDEM simulation are calibrated by using numerical experiments of biaxial compression corresponding to the physico-mechanical parameters. The results indicated that the stress-strain curves are strain softening, and the peak value of deviatoric stress is consistent with the laboratory experiments. Under the dynamic load effect, the glacier slip along the slope direction, and the whipping effect of the speed is obvious. The feasibility of using FDEM method to study discontinuous problems such as ice avalanche is discussed.
Statistical Linearization Method for the Piecewise Nonlinear Systems
Authors: Li L. Y. , Huang B. Y.
Published: June 2019

The Monte-Carlo numerical simulation method is applied to obtain the approximate probability distributions of the response of the piecewise nonlinear systems to random excitation. The expression of the equivalent linearization parameters for the piecewise nonlinear system is derived by the proposed statistical linearization method. To illustrate the accuracy of the linearization method, the present paper has compared the statistical characteristic value obtained by both the Monte Carlo numerical simulation method and the Statistical linearization method, while the time history analysis also shows a good agreement. Linearization of piecewise stiffness nonlinear model is displayed.
Analysis on the Incentive Policy of Vertical Greening in China: a Case Study of Shenzhen City
Authors: Li Yun , Hu Yali , Zhong Jinghua
Published: June 2019

Through the comparison of the current vertical greening policies at home and abroad, the paper analyzes the overall value orientation and policy characteristics of the domestic vertical greening incentive policy based on the type of vertical greening practice, the matching analysis of the incentive policies related to vertical greening in Shenzhen; analyze the existing system, type, relevant departmental responsibilities and implementation effects of Shenzhen’s vertical greening policy, and deeply discuss the shortcomings of China’s current vertical greening incentive policy and propose optimization suggestions.
Corrosion Rate of Low Carbon Steel for Construction Materials in Various NaCl Concentrations
Authors: Ali N. , Putra T.E. , Husaini  , Iskandar V. Z. , Thalib S.
Published: June 2019

Corrosion rate data of metal materials for construction; particularly carbon steel used in wet environments containingNaCl, is very important due to safety reasons. It is, therefore, necessary to investigate the corrosion rate of construction steel in variousNaClconcentrations. The objective of this work is to study the corrosion rate of low carbon steel by varying the concentration ofNaClin distilled water, using a loss of weight method. To carry out this research, 25 low carbon steel samples, of 80x24x3 mm sized coupons, were made. Samples were divided into 7 treatment groups, and weight loss measurements were carried out for 240, 480, 720, 960, 1200, 1440 and 1750 hours, respectively. Experimental data was obtained by totally exposing the samples toNaClsolutions of 2%, 3%, 4% and 5%, and one treatment in distilled water only. The results show thatNaClconcentration significantly influenced the corrosion rate for all solution variations. The most obvious effect was observed in the first 240 hours of exposure time for all concentrations ofNaCl;which then gradually decreased until an exposure time of 1750 hours was reached. The average corrosion rate value was0.2427 μm/year.
Genetic Associations with Indoor Tanning Addiction among non-Hispanic White Young Adult Women
Authors: Mays Darren , Ahn Jaeil , Zhang Bingsong , Atkins Michael B , Goerlitz David , Tercyak Kenneth P
Published: June 2019

Background

Some young people may become addicted to indoor tanning in a manner similar to other forms of addiction, but research on genetic associations with indoor tanning addiction remains limited.

Purpose

To examine if liabilities in genetic addiction reward pathways and psychiatric comorbidity influence the risk of indoor tanning addiction.

Methods

This was a cross-sectional study with a community sample of 292 non-Hispanic white young adult women aged 18–30 years who reported indoor tanning in the past year. Self-report measures included indoor tanning frequency, appearance orientation, depressive symptoms, and two screeners of tanning addiction. DNA samples were analyzed for 34 single nucleotide polymorphisms (SNPs) in candidate genes in addiction reward pathways.

Results

No SNPs were significantly associated with tanning addiction in univariate analyses after multiplicity adjustment. In multivariable analyses adjusting for indoor tanning frequency, appearance orientation, and depressive symptoms, variant genotypes (CC or CT) in two DRD2 dopamine receptor gene SNPs were associated with increased odds of indoor tanning addiction (rs4436578, odds ratio [OR]: 2.30, 95% confidence interval [CI]: 1.11–4.77; rs4648318, OR: 1.95, 95% CI: 1.02–3.72). Variant SNP genotypes interacted with depressive symptoms to increase the risk of indoor tanning addiction: OR: 10.79, 95% CI: 3.25, 35.80, OR: 13.60, 95% CI: 4.13, 44.78, respectively.

Conclusions

This study provides preliminary evidence that DRD2 dopamine receptor gene SNPs are associated with indoor tanning addiction and young women with variant genotypes and elevated depressive symptoms may be at higher risk. These preliminary results support a reward-based model for indoor tanning addiction and warrant further investigation.
Assessing the invasive risk of bark beetles (Curculionidae: Scolytinae and Platypodinae)
Authors: Yu Yanxue , Chi Zhihao , Zhang Junhua , Sun Peishan , Wang Cong , Pan Xubin
Published: June 2019

Bark beetles have been recognized as the main insects that threaten forests worldwide. Several years of research related to evaluating the potential establishment of beetles have yielded widespread recognition of the usefulness of cluster analysis or species distribution models (SDMs) in predicting which species present a high risk of invasion. It is necessary to integrate current practices to quantitatively estimate the risk of establishment. This article analyzes global occurrence data of bark beetles using ‘SOM (self-organizing mapping) + MaxEnt’ to generate the list of high-risk species based on an SOM index and ranges of suitable distribution. All selected countries were clustered into nine clusters to discover which countries have similar bark beetles assemblages. A list of species considering potential threats that were absent from some countries was generated, and Hylurgus ligniperda and Scolytus multistriatus have a relatively high risk of establishment in China. Moreover, MaxEnt were used to analyze the potential geographic areas that species may be invaded. The results indicated that suitable regions of H. ligniperda are distributed in North America, Europe, the Middle East, Central Asia, and the southwest part of China. In addition, S. multistriatus has limited distribution on the Chinese mainland. The integration of SOM and MaxEnt provides a valuable reference for identifying potentially threatening invaders, and assessing the establishment risk for biological invasion, which provide the basis for forest management measures.
Development of a predictive model for drug-associated QT prolongation in the inpatient setting using electronic health record data
Authors: Hincapie-Castillo Juan M , Staley Benjamin , Henriksen Carl , Saidi Arwa , Lipori Gloria Pflugfelder , Winterstein Almut G
Published: June 2019

Purpose

We aimed to construct a dynamic model for predicting severe QT interval prolongation in hospitalized patients using inpatient electronic health record (EHR) data.

Methods

A retrospective cohort consisting of all adults admitted to 2 large hospitals from January 2012 through October 2013 was established. Thirty-five risk factors for severe QT prolongation (defined as a Bazett’s formula—corrected QT interval [QTc] of ≥500 msec or a QTc increase of ≥60 msec from baseline) were operationalized for automated EHR retrieval; upon univariate analyses, 26 factors were retained in models for predicting the 24-hour risk of QT events on hospital day 1 (the Day 1 model) and on hospital days 2–5 (the Days 2–5 model).

Results

A total of 1,672 QT prolongation events occurred over 165,847 days of risk exposure during the study period. C statistics were 0.828 for the Day 1 model and 0.813 for the Days 2–5 model. Patients in the upper 50th percentile of calculated risk scores experienced 755 of 799 QT events (94%) allocated in the Day 1 model and 804 of 873 QT events (92%) allocated in the Days 2–5 model. Among patients in the 90th percentile, the Day 1 and Days 2–5 models captured 351 of 799 (44%) and 362 of 873 (41%) QT events, respectively.

Conclusion

The risk models derived from EHR data for all admitted patients had good predictive validity. All risk factors were operationalized from discrete EHR fields to allow full automation for real-time identification of high-risk patients. Further research to test the models in other health systems and evaluate their effectiveness on outcomes and patient care in clinical practice is recommended.
Multicenter Efficacy Trial of a Percutaneous Radiofrequency System for the Reduction of Glabellar Lines
Authors: Newman James , Chan James , Lorenc Z Paul , Stridde Braden C , Russell David James
Published: June 2019

Background

Bipolar percutaneous radiofrequency (RF) is an established method for ablation of distal peripheral branches of the facial nerve to produce weakness of the corrugator muscle. Recent developments to the Serene RF system (Serene Medical, Inc., Pleasanton, CA) allowing for safer and more predictable results highlighted a need for prospective clinical data.

Objectives

The authors sought to assess the ability of percutaneous RF to safely improve the appearance of dynamic glabellar lines for a minimum of 3 months and up to 1 year.

Methods

This prospective study enrolled 78 patients across 5 centers in the United States. The most distal branches of the medial and lateral facial nerve innervation to the brow depressor/corrugator complex were treated. Follow-up was at 3 days by telephone and in-office at 7 days and 3, 6, 9, and 12 months posttreatment. Patients were evaluated employing the Merz scale for dynamic glabellar lines.

Results

At 3 months, 93.6% of patients had a ≥1-point Merz scale improvement in dynamic glabellar lines based on independent, blinded review. Sustained ≥2-point improvement was present in 60% and 20% of patients at 3 and 12 months, respectively. Overall satisfaction remained >60% through 6 months and >50% at 12 months. All device- or procedure-related adverse events were mild (90%) or moderate (10%) and resolved without medical intervention.

Conclusions

Bipolar percutaneous RF may be adopted in conjunction with surgery or as an office-based procedure where it can serve as a minimally invasive alternative to, or in concert with, Botulinum Toxin A therapy.

Level of Evidence: 4
Seasonal survival and migratory connectivity of the Eurasian Oystercatcher revealed by citizen science
Authors: Allen Andrew M , Ens Bruno J , Van de Pol Martijn , Van der Jeugd Henk , Frauendorf Magali , Oosterbeek Kees , Jongejans Eelke
Published: June 2019

Migratory connectivity describes linkages between breeding and non-breeding areas. An ongoing challenge is tracking avian species between breeding and non-breeding areas and hence estimating migratory connectivity and seasonal survival. Collaborative color-ringing projects between researchers and citizen scientists provide opportunities for tracking the annual movements of avian species. Our study describes seasonal survival and migratory connectivity using data from more than 4,600 individuals with over 51,000 observations, predominantly collected by citizen scientists. Our study focuses on the Eurasian Oystercatcher (Haematopus ostralegus), a species that has experienced a substantial and ongoing decline in recent decades. Multiple threats have been described, and given that these threats vary in space and time, there is an urgent need to estimate demographic rates at the appropriate spatio-temporal scale. We performed a seasonal multi-state (5 geographical areas within The Netherlands) live- and dead-recoveries analysis under varying model structures to account for biological and data complexity. Coastal breeding populations were largely sedentary, while inland breeding populations were migratory and the direction of migration varied among areas, which has not been described previously. Our results indicated that survival was lower during winter than summer and that survival was lower in inland areas compared with coastal areas. A concerning result was that seasonal survival of individuals over-wintering in the Wadden Sea, an internationally important site for over-wintering shorebirds, appeared to decline during the study period. We discuss the outcomes of our study, and how citizen science was integral for conducting this study. Our findings identify how the demographic rates of the oystercatcher vary in space and time, knowledge that is vital for generating hypotheses and prioritizing future research into the causes of decline.
DNA metabarcoding reveals the broad and flexible diet of a declining aerial insectivore
Authors: McClenaghan Beverly , Nol Erica , Kerr Kevin C R
Published: June 2019

Aerial insectivores are highly mobile predators that feed on diverse prey items that have highly variable distributions. As such, investigating the diet, prey selection and prey availability of aerial insectivores can be challenging. In this study, we used an integrated DNA barcoding method to investigate the diet and food supply of Barn Swallows, an aerial insectivore whose North American population has declined over the past 40 yr. We tested the hypotheses that Barn Swallows are generalist insectivores when provisioning their young and select prey based on size. We predicted that the diets of nestlings would contain a range of insect taxa but would be biased towards large prey items and that the diet of nestlings would change as prey availability changed. We collected insects using Malaise traps at 10 breeding sites and identified specimens using standard DNA barcoding. The sequences from these insect specimens were used to create a custom reference database of prey species and their relative sizes for our study area. We identified insect prey items from nestling fecal samples by using high-throughput DNA sequencing and comparing the sequences to our custom reference database. Barn Swallows fed nestlings prey items from 130 families representing 13 orders but showed selection for larger prey items that were predominantly from 7 dipteran families. Nestling diet varied both within and between breeding seasons as well as between breeding sites. This dietary flexibility suggests that Barn Swallows are able to adjust their provisioning to changing prey availability on the breeding grounds when feeding their nestlings. Our study demonstrates the utility of custom reference databases for linking the abundance and size of insect prey in the habitat with prey consumed when employing molecular methods for dietary analysis.