bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of settlement monitoring of underground excavation station vault based on inverted rule method
Authors: Xu Yiteng , Wang Rongli , Deng Peirong , Zou Hao , Yu Zhifa , Li Lixin , Xu Feng , Li Bin
Published: April 2020

In the urban rail transit engineering, there is a great risk in the underground excavation construction of the existing railway station, and the monitoring accuracy of the underground excavation construction is very high. Taking station A of a project as the research object, combined with the construction situation and the structural characteristics of the station, this paper discusses the influencing factors of the vault settlement monitoring in the undercut section of the existing metro station, and formulates the vault settlement monitoring scheme in the undercut section. The feasibility of the method is verified by setting up two sets of independent elevation system and adopting the method of setting up a single station to measure the inverted ruler, and then the error control measures are given. The results show that the method can meet the accuracy requirements of the vault settlement monitoring in the underground excavation section of metro station. This method can provide some technical reference for the similar monitoring project of underground subway station.
Study on quick consolidation method of strong drainage combined with compaction
Authors: Chen Yuntao , Fu Jinbao , Li Feifei , Wang Guijun
Published: April 2020

In this paper, a quick consolidation technique for silt and silty clay foundation with strong drainage combined with compaction is developed through field test. The whole construction period is only 70 days. A strong drainage system is put forward. The whole reinforcement process only needs two inserts and pulls. During the tamping process, the strong drainage system works continuously and saves much time. After consolidation, the bearing capacity of the foundation meets the requirements, and the soil properties are greatly enhanced. The influence depth of consolidation is at least 10 m.
Research on Passenger 3D View Focus of Attention at Airport Terminal Based on Massmotion
Authors: Ma Zhichao , Xiao Yiqiang , Chen Xiong
Published: April 2020

With the development of computer technology, it is possible to simulate pedestrian 3D view focus of attention which affects passengers’ behaviour a lot. The position of passenger 3D view focus of attention is one of the factors that designers should take into consideration. Therefore, there is a necessity to simulate the passenger 3D view focus of attention of the airport terminal. This paper modeled Chaoshan international airport terminal in Jieyang city in Massmotion to simulate passenger 3D vision time on walls. In the vision time map simulated by Massmotion, pedestrian view focus of attention was shown in it. Finally, we proposed a method about simulating the view focus of attention which provides guidance for terminal space design.
Hydrological Variability of Water Level of Dianchi Lake and Its Application
Authors: Wen Deng , Jin Chen , Shixiang Gu , Gang Chen , Jinming Chen , Mi Zhou
Published: April 2020

The water level is an important indicator for lake operation management, and the variability of lake water level will have an important impact on the ecological suitability of aquatic vegetation. The ecological water level of lakes is the minimum water level for maintaining the structural and functional integrity and biodiversity of lake ecosystems. Therefore, it is very important to determine the ecological water level of lakes is for maintaining the harmony and stability of lake ecosystems. This paper analyzed the characteristics of water level, the lowest and suitable ecological water levels and the guarantee degree, by using the monthly water level data of Dianchi Lake from 1961 to 2016. The main conclusions are as follows: (1) The water level of Dianchi Lake mainly had a change period of about 15 years; (2) The abrupt change point of water level of Dianchi Lake occurred in 1994; (3) The lowest and suitable ecological water levels of Dianchi Lake and its actual water level had a typical unimodal distribution. The ecological water level in spring and winter was high, while that in summer and autumn was low. Thereinto, the lowest and suitable ecological water levels in May were lowest, 1885.86m and 1886.04m respectively, while those in November were highest, 1886.60m and 1886.78m respectively. (4) The guarantee degree of the lowest ecological water level of Dianchi Lake was as high as 93%∼95% within the year, while the guarantee degree of the suitable ecological water level could only reach 46%∼50%. The guarantee rate of the ecological water level during the low water level period was higher than that during the high water level period, and the guarantee degree of the interannual ecological water level varied greatly over the years. The lowest guarantee degree occurred in 1988 and 1989 with 0%, followed by the guarantee degrees of 50% and 8% in 1993, and they had reached 100% since 1994.
Vegetation dynamics based on NDVI in Yangtze River Basin (China) during 1982-2015
Authors: Cui Lifang , Wang Zhaoduo , Deng Lihuan
Published: April 2020

Knowledge of vegetation dynamics is important for the sustainability of natural resources and understanding the changes in ecosystems and its impact to earth’s environment. We have carried out analysis of GIMMS (Global inventory modelling and mapping studies) NDVI3g (third generation normalized difference vegetation data for the period 1982-2015. Based on the Linear Regression (LR) analysis, the Mann-Kendall (MK) test with Sen’s slope estimator and Kriging interpolation method, we have investigated the spatiotemporal variations of vegetation NDVI in the Yangtze River Basin (YRB). The results show pronounced increase in the annual mean NDVI at the rate of 0.01/10yr during 1982-2015, with significant turning point (TP) around 1994. The spatial distribution of the annual mean NDVI reasonably increased in the northern, eastern and south-western YRB, while decreased in the Yangtze River Delta (YRD) and parts of the southern YRB during 1982-2015. Pronounced change in NDVI trend is found in different seasons, for example, the increasing trend during spring (0.02/10yr) and in autumn (0.02/10yr) was higher compared to winter (0.006/10yr) and summer (0.002/10yr) seasons.
Sea level variations of Zhejiang province, China
Authors: Zhu Hanjie , Subrahmanyam M.V. , Ji Qiyan
Published: April 2020

This paper shows the sea level variations (SL) over zhejiang province, china. Using Sea surface height data which obtained from the European Centre for Medium-Range Weather Forecasting (ECMWF) and Sea surface temperature (SST) data to validate the correlation of them. Monthly, seasonal, annual and decadal variations of SL over ZJ and its subareas are presented and discussed in this research. SL shows an increasing trend on the whole. However, there is a decreasing trend between the years of 1975 and 1987, then SL shows increase. Over the ZJ province, the rising rate of SL is 0.343cm/a from the year of 1958 to 1975 and the rising rate of SL is 0.238cm/a after the year of 1987. The overall rising rate of SL in the ZJ province is 0.172cm/a from the year of 1958 to 2015, then we can also find that the dropping rate is 0.264cm/a from the year of 1975 to 1987. The Maximum SL height of ZJ province is in 2012. Further SL variations have been done over the ZJ province which includes Hangzhou Bay (HZB), Ningbo (NB), Zhoushan (ZS), Shengsi (SS) and Wenzhou (WZ) areas. We have checked the steric effect with SST on SL. It was found that there was a positive correlation (CC = 0.77) between SL and sea surface temperature (SST), and the same correlation was observed in other areas of Zhejiang Province.
Study on the treatment of livestock farm wastewater by falling water aeration constructed wetland
Authors: Wang Yuelei , Han Yancheng , Zhou Xinyue , Liang Mengyuan , Chu Pingping
Published: April 2020

The livestock farms produce wastewater with high concentration of nitrogen and phosphorus through water rinsing, which is treated by building constructed wetlands. In order to improve the removal efficiency of nitrogen, the author set up a water tank, through falling water aeration to obtain a higher concentration of oxygen to promote nitrification and denitrification reaction. Experiments showed that the removal rates of BOD, NH3-N, TN and TP were 88%, 79.9%, 90.8% and 91.1% respectively. The results show that the experimental removal effect is good, and the results have practical significance for the treatment of aquaculture wastewater.
Research on calculation and optimal allocation of groundwater resources in Rizhao coastal area
Authors: Bengu Yang , Peng Yang , Wei Zhu , Hui Zhang , Benli Guo , Xiaodong Li
Published: April 2020

In this paper, the calculation and optimization of groundwater resources in Rizhao coastal area are realized by means of ground investigation, geophysical prospecting, pumping test, water level measurement and sampling test, groundwater recharge, diameter, drainage and other factors. According to the calculation and analysis of groundwater resources in the investigation area, the hydrochemical types in the investigation area can be divided into eight categories Cl, HCO3, HCO3⋅Cl, HCO3⋅SO4, HCO3⋅NO3, NO3Cl, SO4, and NO3. The mineralization degree is mostly above 0.3g/l. The groundwater recharge in the investigation area is 8638.40×104m3/a, and the groundwater consumption is 6017.12×104m3/a. Furthermore, on the basis of calculation and analysis of groundwater resources, this paper delimits the prohibition and restriction zones of the investigation area by groundwater resources exploitation and hydrochemical properties, and puts forward reasonable exploitation opinions, such as building underground seepage interception dams and constructing groundwater reservoirs, so as to realize the optimization of groundwater resources in the investigation area. This not only guarantees the groundwater resources demand of Rizhao City, but also has certain reference and application value for the rational utilization evaluation of groundwater resources in other regions.
Experimental Study on Acoustic Attenuation of Bubble Wake
Authors: Han Jing , Lv Shuai , Wu Zhongpeng , Zhang Mingwei , Bai Jin
Published: April 2020

When ship sails on the water surface, it will form a wake containing a large number of bubbles for different scales. The existence of bubbles will cause the attenuation of sound waves. In this paper, bubbles with different sizes are generated in the pool by using ceramic tube array. An experimental study on the acoustic attenuation characteristics of sound waves in bubbles was carried out for still water, small bubbles, medium-sized bubbles and large bubbles. Through experimental research, it is found that the existence of bubbles makes the acoustic signal decay obviously. At different frequencies, bubbles decay more than 10dB relative to still water. Large bubbles have the strongest attenuation effect on acoustic signals, averaging over 20dB. The medium and small bubbles are similar to the attenuation of the acoustic signal. The acoustic signal intensity in static water and different scale bubbles is basically the same as the frequency.
Traffic sign change detection based on grayscale adaptive SVM
Authors: Luo Dean , Pan Xingnan , Huang He
Published: April 2020

The use of vehicle image detection to detect traffic information along roads is a key technology for high-precision navigation map updating. At present, China’s roads are developing rapidly. Traffic signs along the roads are constantly updated as the roads change. An accurate and efficient method for detecting traffic signs along the roads is yet to be proposed. Aiming at this problem, this paper proposes a road traffic signage change detection method based on Grayscale Adaptive SVM (Support Vector Machine). First extract the traffic signs in the two-stage image, rotate and interpolate the operation, automatically rotate the guide card to the horizontal, and zoom to the uniform size, grayscale the image pair and extract the changed part using the SVM model, and finally use the morphological operator. Process images to remove the effects of “salt and pepper” noise. Through experimental verification, this method can detect changing areas accurately and efficiently, eliminate the influence of parallax, and have a higher degree of automation.
Study on the functional mechanism of enterprise internationalization strategy adjustment in the digital era
Authors: Shen Zhifeng , Wang Peng , Xu Guize , Jiang Hongbing
Published: April 2020

This article is based on the following research background, ①the transformation necessity of the internationalization strategy philosophy under the trade war; ②the importance of enterprises entering the international market in all countries; ③postmodern consumption and production practices paying more and more attention to the project sharing; ④the innovation mode advocating cooperation and openness in resource sharing;⑤the urgency of study on new concepts such as the digital institutional environment and project sharing and the transformation of international strategy philosophy; ⑥the interaction complexity of all these concepts. First, this paper proposes and defines the concepts of digital institution environment and project sharing, then it studies the innovation mode suitable for digital system environment and the internationalization strategy philosophy, and it studies the logical relationship among digital institution environment, project sharing, enterprise innovation mode and enterprise internationalization strategy adjustment. Second, this paper constructs a conceptual model that how the digital institutional environment influence the internationalization strategy, and it studies the similarities and differences in the context of project sharing and enterprise innovation mode. Finally, combined with the enterprise innovation model, this paper puts forward the construction methods, construction procedures and value realization methods for various sharing platforms. It proposes suggestions for enterprise internationalization strategy actions, and in particular it gives a scientific judgment on the current development trend of internationalization strategy.
Suggestions on Wuhan Humanities Greenway Planning
Authors: Lin Xin , Du Zhehua
Published: April 2020

It can be seen that the humanity greenway is one of the important directions of greenway construction. Wuhan City plans to build a national central city, so the article suggests that Wuhan Humanities Greenway should be positioned as a world-class humanity greenway with unique humanistic connotations. Through analysis, the location of Wuhan Humanities Greenway and the humanistic connotation of Wuhan humanities greenway are proposed. Finally, the article proposes plans and recommendations. In this program, the 5,000-year history is divided into nine sections of history. The greenway is also divided into nine sections, presenting the cultural characteristics of each dynasty.
Dynamic risk assessment method of urban drought based on water balance and optimal allocation analysis
Authors: Sun Keke , Xu Jijun , Yao Liqiang , Yuan Zhe , Pan Deng , Qu Yanping , Miao Henglu
Published: April 2020

Based on the analysis of driving factors of urban drought, this paper adopts different methods of water balance and drought identification for different water supply sources, such as local water storage and transit runoff. By calculating the city water shortage rate and frequency under different water supply conditions and combining with the benefit analysis model of water supply for each water using sectors, the relationship curve between water loss and water shortage rate for each major industry in cities and towns is established. Based on the dynamic optimal distribution of water shortage for each industry and the forecast results of precipitation and runoff, the dynamic loss and risk assessment method for urban drought with different water supply sources is put forward. Taking Qidong County and the towns of Hengyang City along the Xiangjiang River as examples, the model method is validated. The results show that there is a power function relationship between the urban drought loss and the water shortage during the drought period, the models may provide theoretical reference for optimizing urban water allocation management and making urban drought resistance plan.
A Study on Determinants that affect Klang Valley (Malaysia) consumer preference in airline industry
Authors: Veeramani Sugan , Rou Yi Wong , Yoong Ho Min , Mahmud Bahri
Published: April 2020

This study aims to determine the effects that Klang Valley (Malaysia) consumer preferences in airline industry. The primary data were collected through survey questionnaire for this research purposes. Descriptive research design and convenient sampling is sued to conduct the survey. The obtained data were evaluated for descriptive analysis, reliability analysis, normality test, correlation analysis and regression analysis. Major findings of this research project were discussed in order to understand the affects that Klang Valley (Malaysia) consumer preferences in airline industry. The finding of this study shows that the independent variables such as airline reputation, service quality, environmental concern and especially flight fares have most significant relationship toward the consumer preference of airline transport in Klang valley.
Implementation of Green Supply Chain Management in Ready-made Garment (RMG) Sector of Bangladesh
Authors: Gomes Dony , Daud Dazmin
Published: April 2020

In Bangladesh, ready-made garment (RMG) is one of the biggest industries which are facing many challenging issues recently. The study aimed to analyse material, manufacturing, distribution system and recovery procedures of RMG sector to apply green (sustainable) supply chain management. The study used primary data source. The interviewees are selected based on some specific standards. Interviewees are selected according to their position in management and job experience in RMG sector, transport companies engage with garment sector and third party companies such as Buying House. The sample sizes are four respondents which selected from executive level. Three respondents had more than 10 years experiences in RMG sector and a respondent had eight years experiences in transportation company engage with RMG sector. The garments had encouraged to find green designing of raw materials by using eco-friendly elements which not affect the environment. Moreover, the garments had proper use of the raw materials in their production process to minimize the waste of resources due to limited of natural resource.
The optimal pricing for a trade-in program in remanufacturing supply chain
Authors: Huang Fuling , He Juan , Huang Fuyou , Chen YanRu
Published: April 2020

We develop a model to investigate the optimal pricing for a trade-in program in remanufacturing supply chain. Customer choice behavior is introduced, and the generalized Nash bargaining framework is adopted to model the sale agent’s trade-in program in the business-to-business (B2B) market. Moreover, we analyze the impacts of bargaining power of customers on equilibrium decisions and firm profits.
Research on Decision Optimization Method of Avoiding Collision of Inland Ships Based on Intelligent Calculation
Authors: Tang Yuheng , Zhang Ruijia , Mao Yuankang , Shi Te , Fan Cunlong
Published: April 2020

Shipping is one of the main modes of transportation, and the safety of ship operation is very important. The navigation conditions of the inland river are complex. The width of the river, the density of the ships and the height of the bridge all affect the navigation of the ships to a certain extent. Based on this, this paper proposes a decision-making optimization method for collision avoidance of inland ships based on intelligent calculation. By analyzing the process of ship collision, the genetic algorithm in intelligent calculation is used to avoid collision. The simulation results show that the best collision avoidance effect is achieved in the collision avoidance of the two ships and the collision avoidance of the ship and the bridge, which reduces the risk to the lowest level.
A Preliminary Study on Promoting the Use of Solar Energy Roof in Residential Building in Jinan
Authors: li Yanwei
Published: April 2020

The excessive development and utilization of traditional energy makes the energy fuel (oil, coal, etc.) on the earth tend to be exhausted. At the same time, the pollutants discharged in the process of use have caused serious harm to our living environment, resulting in increasingly acute environmental problems such as climate warming and air pollution. Solar energy is inexhaustible clean energy. At present, the use of solar energy in Jinan residential buildings mainly focuses on the installation of solar water heating system in the south facade of the building, while the use of roof of residential buildings is very little. There are two ways to use solar energy on the roof of residential buildings: photovoltaic power generation and light heat conversion. Through these two ways, solar energy is converted into electric energy and thermal energy. There are many favorable factors to promote the use of solar roof in Jinan residential building. First of all, Jinan has a long sunshine time. Secondly, the usable area of Jinan residential building roof is large. In addition, the solar energy roof of Jinan residential building has a double energy-saving effect. Finally, the solar energy roof has little adverse effect on the appearance of the residential building in Jinan.
Research on VFM quantitative evaluation of PPP project based on fuzzy real option method
Authors: Chen Ya , Nie Chunlong , Liu Xueyang
Published: April 2020

Value-for-money evaluation can provide decision-making basis for the selection of public project implementation mode. As far as the current situation is concerned, there is a great controversy in the quantitative evaluation of value for money. This paper attempts to explore the option value ignored in the evaluation process of PPP projects by using the concept of triangular fuzzy number in real option B-S model and combining with the traditional quantitative evaluation model. Taking a tourism creative park project as an example, the uncertainty value range is calculated without completely deviating from the existing evaluation system, so as to provide a more comprehensive perspective for the quantitative evaluation of value for money.
Analysis of Public Cognition on Traditional Village Landscape Environmental Planning and Design—Taking Hetian area as an example
Authors: Wang Xiaodong , Chen Gang , Cui Muyang , Liu Dongdong
Published: April 2020

Traditional villages are a typical representative of the regional human settlements in Xinjiang. In order to clearly understand the general public’s basic understanding of the landscape environment of Nanjiang villages. The author strives to collect individual cognition into group cognition, and conduct data statistics in different categories to form a scientific basis. Therefore, the article takes the traditional villages of oasis in the Tarim Basin (commonly referred to as the southern Xinjiang) as the research base, and uses field visits, questionnaire surveys, and photo shoots. It mainly uses big data survey and analysis software and field surveying and mapping as specific implementation methods. The three independent variables include who was interviewed, the province where the mobile phone IP belongs, and the occupation. The three dependent variables include the recognition of the status quo of the traditional village landscape environment, whether the village residential planning and design should have regional cultural characteristics, and its effect on rural rejuvenation and long-term stability. The two types of variables are comprehensively analyzed by combining them individually and crosswise. The comprehensive results show that the interviewees in this study have wide coverage, reasonable composition and accurate data. From the perspective of data quantification, it is enough to prove that the achievements of rural planning and construction in Xinjiang in China are obvious to all and won the hearts of the people. At the same time, it provides important intellectual support for the planning and improvement of the landscape environment of traditional villages in southern Xinjiang.
AHP_FCE-based high-rise building construction risk assessment
Authors: Li Qingfu , Wang Saisai , Zhang Zhanfeng , Qian Huajie , Pei Junjie
Published: April 2020

There are many uncertain factors in the construction of high-rise buildings. By identifying the risk factors existing in the construction of high-rise buildings, this paper establishes a comprehensive evaluation index system for construction risks of high-rise buildings; and the method of combining analytic hierarchy process and fuzzy comprehensive evaluation is adopted, and the respective advantages are used to establish a construction risk evaluation model; The analytic hierarchy process was used to calculate the weights of the indicators at all levels with the help of MALAB software. The fuzzy comprehensive evaluation method was used to construct the risk evaluation matrix, and the Zadeh operator was used to calculate the evaluation indicators at various levels. The risk factors in the construction process of high-rise buildings are evaluated at the second level and passed. An example verifies the practicability of the above method.
A Changing Process-from climate change to country’s fragility
Authors: Kong Weikaixin , Chu Dantong , Lou Yameng
Published: April 2020

We analyze the impact of climate change to different extent of country’s fragility, using Central African Republic and Mexico as an example of top ten most fragile country and a moderate fragile country respectively. Through our dynamic model, a strong intervention of government is proved to have a significant effect on alleviating the fragility of country. The strengths and weaknesses of our models are discussed and we also propose solution for the fragility of the country. In this paper, we conclude the relationship between climate change and country’s fragility together with the effect of interventions based on our models, which may also give an inspiration for the later dynamic prediction.
Selection of landslide affecting factors based on strong association analysis
Authors: Li Luyao , Liu Rui , Yang Xin , Yang Mei , Yang Yuantao
Published: April 2020

The performance of models in landslide susceptibility mapping largely depends on the selection and combination of affecting factors. The Apriori algorithm proposed in this paper is a factor selection method of strong association analysis, which can select the factors that are most likely to induce landslides from 15 affecting factors. Then combine the origin and optimized factors to build the prediction model of landslide susceptibility by support vector machine (SVM) in machine learning. Afterwards, we verifying the landslide points in the dataset to measure the accuracy of the model. Ultimately, ROC curve was adopted to evaluate the prediction results of the two models. The result reveals that the model based on the combination of optimized factors (AUC 1=0.930) is superior to that based on 15 affecting factors (AUC 2=0.898).
A study on the Evolution of Morphological Vitality of Ancient City along the Silk Road Based on Space Syntax—Taking Zhangye as an example
Authors: Zhang Xiaojuan , Yang Zhiwei
Published: April 2020

Zhangye is one of the Chinese historical and cultural cities announced by the State Council in 1986. It is not only the historical junction of the “Ancient Juyan Road” and the “Ancient Silk Road”, but also an important economic and cultural town and the key position of introduction of Buddhist culture into China.On the basis of morphological evolution, this paper analyzes the changes of the space structure of zhangye ancient city and its status and function as a core in the overall urban space structure through space syntax. At the same time, this paper discusses the public space, road network structure and space elements of zhangye historical area. Especially the internal connection between traditional architecture, landscape, commerce, etc. On this basis, the specific strategies for promoting the vitality and attractiveness of the historical space of Zhangye are proposed, which provides a research foundation for the protection and sustainable development of the historical city in the future.
Effect of frequencies on the change of electrical impedance in sand dunes of Ouargla region
Authors: Remita N. , Chihi S. , Mechri ML.
Published: April 2020

In this paper, we put the accent on the measurement of real and imaginary parts of electrical impedance and effective loss tangent respectively z′, z″ and tgδ in sand dunes of Ouargla region at a range of frequency intervals between 4,6849×10−2 Hz and 1,8593×10+6 Hz with AC voltage of 1.000 V using the impedance spectroscopy. The experimental results revealed that the real and imaginary parts of electrical impedance and effective loss tangent have strong frequency dependence. In the frequencies range (4,6849×10−2 – 4,9385×10−1) Hz z′ < 0 and z″ change between (4,8118×10+2 × 5,0422×10+1) Ω, in the frequencies range (5,4877×10+1 – 2,3426×10+4) Hz z′change between 146,04 Ω and 4,8193 Ω and z″<0. In high frequencies range (1,2599×10+5 – 1,8593× 10+6) Hz z′ change between 4,5359 Ω and 5,0567 Ω. The effective loss tangent values increase until they reach a peak, in frequencies range between 4,6849×10−2 Hz and 2,5197×10−1 Hz, but then the remaining frequency the values decrease until they become constant. The nature of impedance electric variation indicated a possibility to knowledge the polarization of sand dunes of Ouargla region and acquaintance the frequencies when the material is passive devices or active devices. It is also possible to know the quality of equivalent electrical circuit, whether it is induction or capacitance.
Crystal structure: How to use data quality Indicators to select a high resolution cutoff
Authors: Mouha M.AIT , Tlamsamani D. , Yamni K.
Published: April 2020

To get a good quality crystal structure, we should first do the initial analysis of the diffraction data. There are many global indicators of the quality of the diffraction data. Accentuated in this paper are the dmin, deff, C, Rmerge
and Rr.i.m
. Based on the results obtained, this paper will overview in our understanding of how to use these indicators to select a high resolution cutoff that leads to the best crystal structure, using practical examples.
Infrared active modes in double walled CBN nanotube: theoretical study
Authors: Nassir A. M. , Boutahir M. , Fergani F. , Fakrach B. , Rahmani AH. , Chadli H. , Rahmani A.
Published: April 2020

This work focuses on a hybrid system consist of single-wall carbon nanotube inside single-wall boron nitride nanotube (CBN nanotube). The intertube interactions between the outer boron–nitride nanotube and inner carbon nanotube are described using a van der Waals interaction. The infrared spectra of CBN nanotubes are calculated in the framework of spectral moments method. The evolution of the infrared spectra of CBN nanotube as a function of their diameters and lengths are discussed. The obtained results are useful for the interpretation of the experimental infrared spectra of CBN nanotube.
Theoretical study of electronic properties of nitrogen doped carbon nanotubes
Authors: Allali Fatimaezzahrae , Chadli Hassane , Rahmani Abdelali
Published: April 2020

In this work, we have studied the effects of nitrogen (N) substitutional doping on the electronical properties of single wall carbon nanotube (SWCNT). The electronic density of states (eDOS) of these nanosystems has been calculated in the framework of tight-binding calculations method. The obtained results show that the semiconducting SWCNT could be a quasi-metallic one after N-substitution. We conclude that electronic properties of the N-doped nanotubes (SWCNNT) are sensitive not only to the concentration of nitrogen atoms but also to their distribution on the nanotube surface. Our main results are discussed in the light of the experimental data.
Thermal Lattice Boltzmann Method for micro-Poiseuille gas flow
Authors: Elguennouni Youssef , Hssikou Mohamed , Baliti Jamal , Alaoui Mohammed
Published: April 2020

In this paper, the thermal Lattice Boltzmann Method (TLBM) is used to simulate a gas microflow. The simulated gas is confined within an inlet/outlet microchannel and driven by a constant inlet velocity Uin
. The bottom wall temperature is taken to be equal zero while the top wall temperature is decreasing from 1 to 0. For consistent results velocity slip and temperature jump boundary conditions at the walls are used. The rarefaction effects given by the Knudsen number, on the velocity and temperature profile are investigated. The results obtained from the TLBM are compared with those obtained using the Finite Difference Method (FDM). In addition to the good agreement observed between the two methods, the results show an interesting sensitivity of velocity and temperature profiles with the gas rarefaction degree.
Computational Effective Thermal Conductivity of Polyurethane Mixed Cell Foams
Authors: Hermama Chaïmaâ , Elmaliki Anas , Lahbabi Salma
Published: April 2020

The objective of this paper was to calculate effective thermal conductivity of polyurethane foam used in thermal insulation of buildings with a new modeling approach. The proposed approach was more realistic as it simulated the real fraction of closed cells and open cells in the foam and it modeled the real physical phenomena that happen when both types of cells are present. This study was investigated for polyurethane foam with 70 % of closed cells and 30 % of open cells, by using finite element method and numerical homogenization. The result showed that there was a systematic change in thermal conductivity when the type of cell (closed, open and mixed cell) varied at fixed volume fraction. Also the effective thermal conductivity of mixed cell of this PU foam was about λm= 0.07 W.m-1.K-1. Simulation proved the interest of this approach. Indeed, it brought new factor that influence the effective parameters which was fraction of closed cells and open cells. They suggested new method for computing thermal conductivity as a function of thermal conductivity of closed and open cell foam.
Effect of temperature variations on interfacial debonding of FRP-plated beams: A coupled mix-mode cohesive zone modeling
Authors: Wilson Julian , Gao Wan-Yang , Yang Jian
Published: April 2020

The use of fiber-reinforced polymer (FRP) plates for the strengthening of structural members involves their exposure to service temperature variations (i.e., thermal loadings). Such temperature variations may lead to thermal stress and the interfacial debonding of the FRP-plated beam as a result of the thermal mismatch between the FRP plate and the substrate beam. There is lacking research related to the effect of temperature variations on the interfacial debonding of FRP-plated beams. This paper presents the first-ever analytical study on the behavior of the FRP-plated beam under combined thermal and mechanical loadings. The interfacial stress and slip evolutions as well as the debonding process of the FRP-plated beam are estimated based on a coupled mix-mode cohesive zone modeling. In addition, a finite element (FE) approach is proposed to verify the analytical solution in which the analytical results are compared with the FE model predictions, indicating that a good agreement was achieved between the analytical and FE results.
Molecular dynamics simulations the effect of temperature on the plastic deformation mechanism in aluminum single crystal
Authors: Wang Zhao , Li Yalin , Hu Ting , Cai Jun
Published: April 2020

Molecular dynamics simulations are performed to investigate the effect of temperature on the plastic deformation mechanism in aluminum single crystal. It is found that as temperature increases the Yield strength and Young’s modulus of the aluminum under compressive and tensile strain will reduce. Moreover, it is found that the higher temperature is, the easier the dislocation emission is. Under compressive strain, the proportion of 1/6<112> Shockley type of dislocations to total dislocations is found to increase with the temperature increasing. It is also found that only a large amount of dislocation occurring incipiently the strength of the material can be yield.
Stress intensity factor of circumferential periodic cracks on tube with stiffened plates under tension
Authors: Yuan W J , Xie Y J
Published: April 2020

Fracture is one of the most common failure of engineering structure and the stress intensity factor is the key parameter used to decide whether the structure will crack or not. This essay is based on the concept of conservation law and the tension theory in mechanics of material. It analyzes the stress intensity factor of circumferential periodic cracks on tube with stiffened plates, it obtains the specific expression of stress intensity factor of circumferential periodic cracks on tube with stiffened plates under tension. Finite element method is used for checking the stress intensity factor of cracks and proving the accuracy of expression’s results. The method which proposed in this essay is easy to calculate and can get the closed solution.
Additional bending moment of thick-walled elliptical tube under internal pressure
Authors: Chen Gang , Chu Guan-Nan , Lin Cai-Yuan
Published: April 2020

With the development of industry, the elliptic-sectional tube is widely used in some special situation. In this paper, a theoretical model is developed to calculate the additional bending moment of thick-walled elliptical tube under the internal pressure, based on the structural static force method. The effects of internal pressure and ellipticity on the additional moment were discussed. At last, finite element analyses were conducted and the results were compared with the theoretical results to verify the correctness of this theoretical model. This model can provide a guideline for determining the maximum additional bending moment of elliptic, and help in estimating the failure of the elliptical tube under the internal pressure.
Predictive modeling of surface roughness in the inner thread grinding considering the effects elastic deformation
Authors: Fang Cui , Zhao Yongsheng , Yang Congbin , Liu Zhifeng
Published: April 2020

Surface roughness is an important factor to consider in the field of precision manufacturing. In this study, a model of the surface roughness in inner thread grinding that takes into account the thread helix angle and effect of elastic deflection between the wheel and the workpiece is presented. The surface roughness is analyzed under different spindle speeds, workpiece speeds, grinding depths, and thread helix angles. The proposed model provides a theoretical basis for the optimization of high-precision inner thread grinding.
Projection Intensity Adjustment Method Based on Multi-threshold for Fringe Projection Technology
Authors: Yu Changzhi , Ji Fang , Li Fang
Published: April 2020

Three dimension measurement based on fringe projection technology is widely used in precision manufacturing. However, when measuring objects with reflective surfaces, the measurement accuracy is reduced due to image saturation. This paper presents a projection intensity adjustment method based on multi-threshold. The reflectivity information of fringe pixels and scale factor are used to calculate the multi- threshold. According to the multi-threshold, the optimal projection intensities are obtained, which reduces the image saturation and improves the measurement accuracy. The experimental results show that this method can improve the measurement accuracy effectively.
Study on the envelope process of the flexspline of harmonic reducer based on the angle of wave generator
Authors: Zhang Tao , Liu Zhifeng , Yang Congbin , Hu Qiushi
Published: April 2020

Harmonic reducer is the core part of robot joint, its tooth shape design theory and meshing characteristics will directly affect the motion control accuracy and vibration characteristics of robot. This paper studies the meshing process of the circular spline and flexsplines of the harmonic reducer based on the double arc profile and the elliptical wave generator. The main innovation of this research is to take the input angle of the wave generator as an independent variable, which more clearly represents the enveloping process and meshing interval distribution of the tooth profile. The results show that the secondary meshing process of the double circular arc tooth profile exists on both sides of the long axis of the wave generator. But the second conjugate contact interval is small, so the optimization of tooth shape should focus on the first conjugate interval. This study provides a theoretical basis for the design of tooth profile parameters of harmonic reducer.
Research of electric heating control based on model predictive control algorithm
Authors: Zhang Chao , Liu Bo
Published: April 2020

In order to improve the heating efficiency and control precision of electric heater, the method that applying the model predictive control algorithm to electric heating control was proposed. According to the analysis of electric heating characteristics, it was proposed that taking PID controller and the electric heater as the generalized object of the control to improve the dynamic response and the linearity. For realizing model predictive control, the system framework of this algorithm and the operating steps of controller were designed. The result of simulation and experiment proved this method effective and superior over the traditional control. Finally, the analysis on some parameters of controller provides a reference for others who interested in this study.
Research on Calibration Technology of Five-Degrees-of-Freedom Tandem Robots
Authors: Li Zhe , Zhang Zhijing , Yao He
Published: April 2020

In the robot feedback control system of visual feedback, the calibration of the hand-eye system is very important, because it directly affects the accuracy of the robot. Aiming at the small operating space and compact structure of the micro-assembly robot system, a fixed-vision hand-eye calibration method is proposed. The method first obtains the coordinates of 15 spatial points in the robot base coordinate system, and then uses the camera pose measurement principle to obtain the coordinates of the corresponding spatial points in the camera coordinate system, and then establishes the calibration equations. Based on the least squares method, the coordinate transformation matrix between the hand-eye systems is calibrated. The experimental results show that the constructed hand-eye system coordinate transformation matrix is effective and reliable. The calibration accuracy and effectiveness of the method are verified by relevant grabbing experiments.
Target Detection and Tracking System Based on FPGA
Authors: Yu Xiuli , Li Bingqi , Dong Mingshuai , Yin Weimin
Published: April 2020

The parallel processing mode of Field Programmable Gate Array (FPGA) and the ability to perform multiple tasks repeatedly meet the real-time and flexible requirements of target detection and tracking. The FPGA of Cyclone IV of ALTERA company is adopted as the hardware processor for the system platform to filter and preprocess color conversion of the collected image. The edge detection method of Sobel operator is adopted to realize the convolution and binarization processing of the third-order matrix of pixel points and the operator template, and the inter-frame difference algorithm is applied to the moving target. At the same time, the tracking algorithm based on centroid feature matching can realize the real-time tracking of target position. The system uses the characteristics of high real-time, low power consumption, parallel processing and strong expansibility of the FPGA, transplants machine vision algorithm into the FPGA, reduces the delay of image processing, and completes the hardware implementation of the target detection and tracking algorithm. Finally, the experiment verifies the real-time performance and effectiveness of the algorithm.
Research on Fault Diagnosis Method of Gearbox Based on SA and BP-AdaBoost
Authors: Zhang Yangyang , Jia Yunxian , Wu Weiyi , Su Xiaobo , Liang Dong
Published: April 2020

In order to solve the problems of difficult selection of state feature parameters and poor accuracy of single BP Neural Network in gearbox fault diagnosis, a gearbox fault diagnosis method based on SA and BP-AdaBoost is proposed. Taking the typical fault of a gearbox as the research object, the vibration signal of the typical working state of the gearbox is collected through the preset fault experiment. The time domain statistical parameters with high sensitivity is selected as the feature vectors by the Sensitivity Analysis method. Then these state feature vectors are input into BP-AdaBoost model for training and testing, and their results are compared with those of BPNN model. The results show that the proposed method can quickly and effectively diagnose the fault of gearboxe, and is better than BPNN model.
Analysis of water jetting happened in volute manhole of the hydropower plants
Authors: Li Wenbo , Liu Lanlan , Feng Xiang , Xiao Jian , Qi Fei , Zhou Hengyi , Zhang Jun
Published: April 2020

The water injection in the volute manhole of a hydropower plant was investigated and analyzed. The analysis results showed that the main reasons for the cracking and water jetting happened in the volute manhole were that, firstly, the opening of the volute manhole was not reasonable, the reinforcement structure was damaged, and the reinforcement strength was insufficient. Secondly, the welding quality was poor, which caused the weld defect to become a cracking source and expand into a crack.
Research on Ecological Driving Strategy of Urban Road Vehicles under Vehicle-road Collaborative Environment
Authors: Su Dan , Cong Wanjuan , Jiang Kun
Published: April 2020

With the increase of motor vehicles, the energy resources available for vehicles have become scarce. In view of the harmfulness of traffic emissions, energy conservation and emission reduction have become strategic goals for the development of the transportation industry. Guiding students to realize ecological driving and reducing vehicle fuel energy consumption and emissions have increasingly attracted the attention of researchers. We are supposed to do a research on signalized intersections at important nodes of urban transportation, use ecological driving to simulate the operation of bicycles and vehicle queues, establish an ecological driving model, and control energy conservation and emission reduction goals from multiple perspectives. This paper combines the ecological driving technology and micro fuel consumption calculation model under the vehicle-road collaborative environment to study the fleets within the signalized intersection. At the same time this paper proposes street signs, models, and case applications that can effectively reduce the average fuel consumption and parking times of the vehicles passing the signalized intersection to ensure the smoothness of operation at signalized intersections has been reduced, and rapid acceleration and deceleration operations have been performed. After verification, the establishment of the fleet’s eco-driving model has great effectiveness.