bluuebunny/crossref_metadata_2025 huggingface dataset:
Inkjet-Printed Flexible Temperature Sensor using Hybrid Reduced Graphene Oxide – Silver Nanoparticles(rGO/AgNPs) Conductive Ink and Silver Nanoparticles Ink
Authors: Liew Q.J , Abdul Rashid N. , Lee H.W , Hawari H.F. , Md Khir M.H.
Published: June 2021

This paper presents a new temperature sensor, inkjet-printed with the in-house developed hybrid rGO/Ag nanoparticles ink (rGO/AgNPs ink). Its performance is studied, and the results indicate that its sensitivity is better than the commercial sensor. The meander—shaped electrodes were fabricated using drop-on-demand inkjet printer (Fujifilm Dimatix 2850 printer) on polyethylene terephthalate (PET) substrate. Compared to the sensitivity 0.0543 ?/oc of the sensor developed with commercial ink, the in-house developed sensor shows higher sensitivity 0.1086 ?/oc. Besides, the printed sensors exhibit its resistance increasing linearly with temperature from 30°C to 100°C. The bending tests results also prove that the characteristics of the sensors do not vary significantly, indicating excellent mechanical stability and flexibility. Therefore, the flexible inkjet-printed temperature sensor with the in-house hybrid rGO/AgNPs ink is recommended for the large-scale productions and implementations.
Real-time Dynamic Traffic Light ControlSystem with Emergency Vehicle Priority
Authors: Ariffin Wan Nur Suryani Firuz Wan , Keat Cheah Seng , Suriyan Terrance Prasath A/Ludhaya , Nore Nurfadzilah Aqilah Mohamad , MohamadIrfanSyaaramiMohdLazim  , HasneezaLizaZakaria  , Hashim Nur Baya Mohd , Zain Aini Syuhada Md
Published: June 2021

Traffic light control systems are widely used to monitor and control vehicles’ flow to provide a smooth and orderly flow of traffic by controlling which lane should be granted to pass through the intersection point without compromising on safety standards. However, a conventional traffic light system handles neither dynamic traffic flow nor the prioritization of emergency vehicles (EVs). Consequently leads to congestion as the conventional traffic light grants underutilized road lanes to have the equal cycle length as a congested lane and possibly causes an accident and delay when multiple EVs are approaching the intersection. This paper proposes an intelligent system that dynamically adjusts the cycle length for each of the lanes at an intersection based on the vehicular density and grants the different types of EVs to pass through the intersection point by assigning different priorities. The system consists of three modules, the traffic light control module, the emergency Radio-frequency identification (RFID) moduleandtheinternetmodule. Thetrafficlightcontrolmoduledetectsvehiculardensityusing ultrasonicsensorsandassignsadynamicsetofcyclelengthbasedontheindividuallanedensity condition. TheemergencyRFIDsareinstalledon differenttypesofEVsbasedonthepreset priority weights. The internet module allows the dynamic traffic light system to be controlled by authorized personnel in a real-time application.
Evaluating the Effectiveness of Course Assessments Method in Determining Student’s Competency Level in Programming
Authors: Salleh Faridah Hani Mohamed , Drus Sulfeeza Md , Gunasekaran Saraswathy Shamini , Dewi Deshinta Arrova
Published: June 2021

Students who choose to study in Computer Science in Malaysia at the Degree level, basically have a diverse background of academic achievement at the final level of their secondary school. Although there are minimum requirements set for admission to Computer Science courses, students tend to demonstrate different achievements after being at university. It is possible that the method of evaluation of educational institutions is not in line with the actual skills mastered by the students. Therefore, this study takes all the test data that has been collected before and assesses which type of test is actually most effective to determine the level of student’s competency in programming. This study proves that compared to other type of assessments, students’ achievement in the final examination, additional lab assessment with challenging questions and test correlated positively with the student’s programming competency. Our experiments also prove that if the final exam score is less than 60%, it is very likely that the student should be classified as incompetent. This suggests the final exam marks should carry significant weightage so that students do not just rely on carried marks to get a high grade.
A Blind Recognition Algorithm of Scrambler after Convolutional Encoder
Authors: Wang Zhongfang , Zhai Liuqun , Fu Jingwen
Published: June 2021

In a wireless communication system, the data is usually scrambled after channel encoding. However, existing research on blind recognition often ignores the pseudo-random scrambling of channel encoding data, which is not in line with the actual situation. To solve this problem, this paper proposes an algorithm to recognize the scrambler parameters with convolutional codes. First, we transform this problem into a cognition problem of cancelling scrambling sequence by using the properties of the polynomial of scrambler. Then, we put forward a fast judgment method after the cancellation of scrambling. The proposed method is based on the conditional entropy and can effectively identify the scrambler after the convolutional encoder. The method has a better performance of resisting error comparing to the traditional method and saves computing resources. Simulation results show that the parameters of the scrambler can still be determined effectively when the bit error rate is 6% in the case of sufficient data.
Data Augmentation Using DCGAN for Improved Fault Detection of High Voltage Shunt Reactor
Authors: Zhu Ming , Zhang Zongxi , Mei Jie , Zhou Kejian , Chen Pengan , Qi Yongka , Huang Qinqing
Published: June 2021

High voltage shunt reactor is an important equipment of power transmission systems. The accurate assessment of their operating status and the timely and correct diagnosis of faults and defects concern the operation safety of the entire grid. Health assessment of high voltage shunt reactors based on vibration signal, which can be used to characterize the hidden troubles of it, is a topic widely studied in deep learning and fault diagnosis. A large number of samples are needed to train the deep learning model, but it is not easy to acquire enough fault samples in the actual scene. In this paper, we utilize a Deep Convolutional Generative Adversarial Networks (DCGAN) to generate synthetic fault samples and enlarge the fault dataset to train the Convolution Neural Network (CNN) fault detection model. Results reveal that the performance through the CNN model can be improved by 3% with the synthetic samples generated by DCGAN, which is better than that of traditional Synthetic Minority Oversampling Technique (SMOTE) algorithm.
Design of Face QR Code Recognition System based on PCA
Authors: Tan Linglong , Wu Fengzhi , Wang Qing
Published: June 2021

This article discusses the face two-dimensional code recognition technology, using the PCA algorithm to study the dimensionality reduction processing process of the face image. Based on the analysis of QR encoding and decoding methods, the generation of face two-dimensional codes is realized. Choose 140 pictures in ORL face database as the experimental data set, study the face two-dimensional code recognition system, and realize a process of face recognition. The experimental results show that the face image data has a large dimension, and the principal component analysis method can be used to obtain the key data. Through the experiment, PCA can be used to reduce the dimensionality to obtain the effective information of the face, and to encode and decode the two-dimensional code. The ZXing two-dimensional code open source library called by the experiment has high experimental efficiency, which is beneficial to improve the operating efficiency of face two-dimensional code recognition and facilitate the machine to complete the simulation.
Image Compression and Reconstruction Based on PCA
Authors: Tan Linglong , Wu Fengzhi , Li Weilong
Published: June 2021

In view of the disadvantages of large image space, high dimension of feature representation and large storage, this paper uses principal component analysis to compress the data, which can effectively reduce the loss of information, reduce the dimension of data and extract features in all aspects of image compression. In this paper, based on the analysis of PCA algorithm dimension reduction, reconstruction, feature extraction principle, the PCA algorithm is applied to image compression and reconstruction. Through the principal component analysis of sample variables, the feature vector of sample variance is calculated, and its principal component is extracted, and the contribution rate is calculated to realize image PCA compression. By extracting different eigenvalues from the original image and calculating its compression ratio and contribution rate, we can see that the clarity of the image is positively correlated with the value of the eigenvalue, and the larger the value of the eigenvalue, the higher the contribution rate. PCA based image processing technology is simple to use, high compression rate and high quality of image reconstruction, which is unmatched by many other methods.
Research on Mathematical Model of Strip Slip during Speed Increase of the Bridle Roll of SPM
Authors: Wang Yong-Qiang , Li Yang-Long , Wen Jie , Yu Meng , Li Gong-Yin
Published: June 2021

When the strip slip occurs during the speed-up process of SPM, there is the relative slippage between the strip and the bridle roll. It will cause the fluctuation of rolling force, elongation and tension of SPM, which are harmful to the strip surface quality and stable operation. For the sake of researching the mechanism of relative slipping happens between the bridle roll and strip when the speed of the skin pass mill (SPM) is increased, a mathematical model for relative sliding between the strip steel and the bridle roll was built. At the same time, a quantitative parameter named “the strip slip risk ratio” was proposed. On the basis of this model, a lot of factors that affect the slip were analyzed, such as friction coefficient, front and rear tension, velocity, acceleration, coiling angle and etc. The results show that increasing friction coefficient, decreasing tension difference, decreasing velocity and acceleration will reduce the slip risk of sliding strip. According to the calculation results, the controllable influencing factors for strip slipping were optimized. The roughness of bridle roll was increased from 4 to 5 microns. The tension difference of bridle assembly at the outlet of SPM was decreased by 50% and the strip acceleration of SPM was reduced from 0.6 to 0.5 m/s2. After application of measures, the monthly incidence of strip slipping is obviously reduced. The incidence of strip slipping per month is reduced from about 3.33% to 0.17%, which prevents the slip between strip and the bridle roll during the speeding process of SPM.
Adaptive Probabilistic Broadcasting for Floating Content
Authors: Shuai X Y , Zhang B , Yin Y X
Published: June 2021

Floating Content (FC) is emerged by bounded geographical zone in a mobile ad hoc network (MANET) to live in the anchor zone (AZ) for special applications such as emergency messages and traffic information for some time. To improve the availability, accessibility and reduce the number of FC duplication, the adaptive probabilistic broadcasting for FC (APFC) based on the number of neighbours and the informed node location is proposed. When a node without FC enters the transmission radius of informed node that is with FC. By exchanged message with the new node, the informed node obtains the information of the new node and its own neighbours. The informed node calculates the transmission probability p based on the collected neighbour information. Then the node automatically selects whether to use APFC or broadcast the FC according to the current position. The algorithm is simulated in different randomly networks. The results show that this algorithm outperforms other broadcasting algorithms in FC duplication.
Virtual Technology in New Media
Authors: Wu Qixiang , He Lin
Published: June 2021

Virtual technology and new media blend with each other and continue to collide, adding different fun to our lives. The interactive design in virtual technology allows people to see the world in the eyes of new media more realistically, making art closer to life and making the picture more vivid and vivid. The new media environment also makes virtual technology useful. It is no longer a tall thing in the eyes of ordinary people, so that ordinary people can also feel the changes that this technology brings to life. With the impact of the digital information age, people can quickly meet their needs for information and accelerate their pace of life; and in the process of impact, art and data blend with each other to form a new art form of new media art. This article focuses on the application of virtual technology in the field of new media. By establishing a new media database model and combining the interactive functions of virtual technology, the necessity of integration of virtual technology and new media is proposed. The data shows that 300 packets are sent per second, each packet size is 600bites (these can be set in the configuration file), the bandwidth of the transmitted data is 0.81Mb / s, and the upper crosshead model is obtained. The results show that many functions of virtual technology are applied in the field of new media.
Shrub growth in the Alps diverges from air temperature since the 1990s
Authors: Francon Loïc , Corona Christophe , Till-Bottraud Irène , Choler Philippe , Roussel Erwan , Carlson Bradley Z , Morin Samuel , Girard Brigitte , Stoffel Markus
Published: June 2021

In the European Alps, air temperature has increased almost twice as much as the global average over the last century and, as a corollary, snow cover duration has decreased substantially. In the Arctic, dendroecological studies have evidenced that shrub growth is highly sensitive to temperature—this phenomenon has often been linked to shrub expansion and ecosystem greening. Yet, the impacts of climate change on mountain shrub radial growth have not been studied with a comparable level of detail so far. Moreover, dendroecological studies performed in mountain environments did not account for the potential modulation and/or buffering of global warming impacts by topography, despite its possible crucial role in complex alpine environments. To fill this gap, we analyzed a network of eight sites dominated by the dwarf shrub Rhododendron ferrugineum. The sites selected for analysis represent the diversity of continentality, elevation and slope aspect that can be found across the French Alps. We quantified annual radial increment growth for 119 individuals, assembled meteorological reanalyzes specifically accounting for topographic effects (elevation, slope and aspect) and assessed climate-growth relations using a mixed modeling approach. In agreement with a vast majority of dendroecological work conducted in alpine and arctic environments, we find that the number of growing degree days during the snow-free period snow-free growing degree days (SFGDDs) is a strong and consistent driver of R. ferrugineum growth across all sites since 1960 until the late 1980s. We also document a marked loss of sensitivity of radial growth to increasing SFGDD since the 1990s, with this decoupling being more pronounced at the driest sites. Our observations of the spatial and temporal variability of shrub sensitivity to limiting factors can be compared to the ‘divergence’ problem observed in tree-ring series from circumpolar and alpine regions and, accordingly, sheds light on possible future trajectories of alpine shrub growth in response to ongoing climate change.
Holistic energy efficient design approach to sustainable building using monitored energy management system
Authors: Buzatu R , Muntean D , Ungureanu V , Ciutina A , Gireadă M , Vitan D
Published: June 2021

Building sector focuses on surpassing challenges linked to energy efficiency and mitigation measures related to greenhouse gas emissions, in consequence, it needs to improve building performance in the interest of decreasing impact over environment. Buildings with reduced long-term operating cost, environmental-friendly and moderate construction costs can be achieved only by multi-object optimization and cross-disciplinary analysis, embodying a holistic approach. Following the main principles of the holistic sustainable design approach, the paper presents a sustainable experimental modular laboratory involving various strategy in regard with sustainable building, as resource, cost and material efficiency, health and well-being, environmentally conscious design, life cycle design, modular design, reusable/recyclable element, environment-friendly demolition method, safety design, consideration of life cycle cost, materials cost and waste disposal cost. Besides the installation of renewable energy sources and conservation of energy, the holistic construction of laboratory included also an integrated design with consideration for technology, operation and maintenance, which involved the implementation of a monitored energy management system. The system provides an accurate overview of the building’s performance during operational phase. Although the monitoring is still in an incipient phase, recordings showed promising results regarding the behaviour of recycled-PET thermal wadding used for insulation and indoor comfort conditions.
Review of an innovative thermal and economic model of a thermal solar source
Authors: Dragne H , Iordache F
Published: June 2021

This paper presents an innovative calculation method that simplifies the present calculation in the existing Romanian solar methodology, but also brings a new approach to the problem of determining the actual efficiency of a heating system using solar panels during the actual hours of sunshine. This new method will also make better economical estimations by including a new calculation method that is adapted strictly to solar panels applications. Both proposed methods, include a new approach of determining the thermal and economic indicators faster or more precise. The results shown in this article, validate the new calculation method and offer new perspectives on real-time hourly solar system performance evaluation. Those results show that although the actual hourly efficiency of the solar panels increases over a small period of time, daily system efficiency that includes the consumer’s heating needs, decreases due to the limitation of the required thermal energy over a longer period of time that exceeds those sunshine hours. This paper provides a new vision regarding the way solar systems are treated and suggests some adjustments that need to be made in calculating the solar systems. Thus, due to a considerably higher heat input over a given period of the day, it is concluded that these systems work much better in the case of extra storage of this energy (larger storage tank) or by adjusting the indoor temperatures (through automation) during this solar charging regime.
The influence of characteristics of aggregates on performance of asphalt mixtures
Authors: Ene N M , Răcănel C
Published: June 2021

Under the current conditions of road traffic growth, importance should be given to the use of construction products whose technical characteristics have to be tested and to comply with the regulations in force. In our country at present there is the European standard EN 13043:2003 regarding the conditions that natural and artificial aggregates must meet in order to be used in asphalt mixtures. As is well known, these conditions are presented in the form of categories of values to be set by the designer to result in an asphalt mix with certain characteristics. However, this standard does not contain a national annex with specifications on the aggregate categories depending on the type of asphalt mix correlated with the technical class / road / street technical category. The majority of beneficiaries that use aggregates in the production of asphalt mixtures have problems on the national market because there is no correlation between this standard and the national provisions in force, namely the AND 605/2016 (version in force on this date). This paper analyzes the conditions that the natural aggregates for the bituminous mixtures must have and correlates the performance of the aggregates with the performance of the asphalt mix.
Shared energy storage market operation mechanism to promote new energy consumption
Authors: Zhang Xinlin , Zhang Yanchi , Zhao Yuzhuo , Chen Dong , Li He , Xie Da
Published: June 2021

The configuration of energy storage helps to promote renewable energy consumption, but the high cost of energy storage becomes a major factor limiting its development. Through shared energy storage, the utilization rate of energy storage can be improved and the recovery of energy storage investment costs can be accelerated. This paper first introduces the application scenarios of the proposed shared energy storage, then analyzes the characteristics of shared energy storage. Furthermore, the transaction process between new energy and shared energy storage is put forward, and the clearing model of shared energy storage market is established. To minimize the consumption cost of new energy generators by coordinating the sharing of idle energy storage capacity. Finally, the proposed method is verified through examples to analyze the benefits of shared energy storage for investors and new energy generators, as well as the changes in new energy consumption.
System simulation of air-cooling single effect LiBr absorption refrigerating system driven by solar heat source
Authors: Zhou Yu , Yan Guihuan , Wang Xu , Hui Xiaoyang , Xu Chongqing , Han Tao
Published: June 2021

Air-cooling single-effect absorption refrigeration system has the characteristics of water saving, space saving and maintenance cost compared with water-cooling. In order to study the characteristics of air-cooled system, this paper uses Aspen Plus to build an air-cooled single-effect LiBr absorption refrigeration system with a cooling capacity of 23kW and adiabatic evaporation and adiabatic absorption, and the influence of temperature on the system at different condensing temperatures is studied. The results show that with the increase of generating temperature, the load increase of solution heat exchanger gradually slows down and then becomes faster, while the load increase of other equipment gradually slows down. After the system COP value rises to a certain value, it basically remains unchanged.
Optimization Analysis of AVC Adjustment Strategy for Power System with Large-scale Wind Power
Authors: Liu Jin , Li Tong , Xu Mingyu , Chen Xiaoguang , Hu Yuanting , Mu Xinghua , Liu Zhiyang
Published: June 2021

As a kind of economical and clean renewable energy, wind power generation is more and more widely used. Wind power plants are far away from the load center and the output power is highly random. Therefore, the control of reactive power, voltage and network loss at public connection points are more difficult. The automatic voltage control system uses the real-time operating data of the power grid to select the best reactive voltage control scheme from the perspective of the entire system. It takes the voltage safety and quality as the conditional limit, takes the economy of the system as the goal, and optimizes the voltage in real-time control. This article gives a control strategy for the problem of inability to smooth transition and repeated oscillations in the signal processing of the abnormal state of the AVC system. The upper and lower limit planes of voltage and reactive power are divided into 27 areas, and each area corresponds to different control strategies. This method can be used to achieve smooth transition of control strategy, real-time voltage optimization control.
Research on Risk Assessment Techniques of Offshore Wind Power Projects during Operation Period
Authors: Liu Baozhan , Jin Weiwei , Zhao Jianping , Zhang Qinfan , An Wei
Published: June 2021

In light of the complex operating environment and high maintenance cost of offshore wind power projects, a risk evaluation system is established in accordance with the risk’s features and sources during the operation period of offshore wind power projects. On grounds of the risk evaluation system, a risk assessment method for offshore wind power projects during the operation period is put forward based on the multi-level fuzzy comprehensive evaluation method, and a specific project in the South China Sea is evaluated with the assessment model. The results showed that the risk probability is moderate to low, the consequences of the hazards are moderate, and the comprehensive risk rating is moderate for the assessed project during the operation period. It is necessary to follow the ALARP (As Low As Reasonably Practicable) principle to mitigate the risk. The risk level of offshore wind farms during the operation period can be judged using the evaluation method to provide technical support for prevention and emergency response of the accidents related to the offshore wind power projects.
Experimental study on pressure fluctuation characteristics of model pump in Huangjinxia hydro-junction
Authors: Dong Peng
Published: June 2021

In this study, the pressure pulsation characteristics of different position in the model pump unit are studied by experiments in combination with the Huangjinxia hydro-junction. The pressure pulsation of the inlet pipe, the volute outlet and the area between impeller and guide vane under different operating conditions were measured and analyzed. The results show that the maximum pressure pulsation amplitude of the pump is less than the guaranteed values by comparing the test results with the value requirement of the pump, which ensures the safe and stable operation of the pump. FFT transform is used to analyze the main frequency and amplitude of pressure pulsation. The main frequency and secondary frequency at the impeller inlet are respectively 15.29 and 7.65 times of the rotating frequency, which are 2 and 1 times of the blade frequency. The amplitude of main frequency at each monitoring point increases with the increase of head. The test results of pressure pulsation value meet the requirements of the contract in the whole pump operation rang.
Numerical Analysis of Wind Wake Superposition and Boundary Layer Interaction
Authors: Barasa Maulidi , Li Xuemin , Zhang Yi , Xu Weiming
Published: June 2021

Understanding the wake impacts to a wind farm is critical for layout planning and turbine design. Wind Wake Models estimates wake development through a single turbine which is then aggregated with a wake variety of methods to calculate the combined wake profile for a wind farm. This study considered downstream wake interactions, and the energy content in the wake profile as the wake developed for three rows and five downstream turbines. This study also looks at the influence of different atmospheric stratifications to wind farm wake superposition. Our findings for the wake and boundary superimposition model determine that the streamwise velocity component range from 8.8 to 9.0 m s-1 (98 to 100 %) for the stable ABL ranges and 8.92 to 9.0 m s-1 (99 to 100 %) for the unstable ABL ranges. This study further determines that the minimum streamwise velocity for the stable and unstable ABL are 8.97 and 8.96 m s-1, and the mean normalized velocity deficit for the stable and unstable ABL are 0.972 and 0.975. The wake deficit for the superimposition of a coupled wake boundary model in the stable case surpasses that of the unstable case due to lower turbulence.
Safety analysis and forecast of new energy vehicle fire accident
Authors: Xiaoggang Wang , Futang Xing , Guixin Shi , Yue Huang
Published: June 2021

In recent years, due to the aggravation of air pollution and the exhaustion of coal and oil resources, new energy vehicles have achieved rapid development. However, new energy vehicles have many hidden dangers. Spontaneous combustion, explosion and other accidents often occur all over the world, which restrict the development of new energy vehicles. In this paper, the fault tree analysis method is used to qualitatively analyse the new energy vehicle, the accident diagram is obtained, the importance of each basic event is analysed, and the fuzzy decision method is used to predict the fire accident of new energy vehicle.
Application techniques for micro capsules on energy security: A case study on Class B fire
Authors: Dong Yan , Zhao Chen Yu , Lv Xiao Zhe , Zhang Tian Wei , Zhang Cun Wei
Published: June 2021

At present, with the rapid development of the national economy, China’s demand for energy is becoming stronger. It is particularly important to develop an efficient and environmentally friendly fire extinguishing agent to ensure energy security. As a new type of environmentally friendly fire extinguishing agent, dry water has the advantages of both water mist and dry powder fire extinguishing agent. The core-shell structure of dry water fire extinguishing agent makes it have fluidity and dispersibility similar to powder fire extinguishing agent, while maintaining extremely high-water content, making it of great application value in the field of fire extinguishing agents. In this paper, the preparation, physical and chemical properties of dry water extinguishing agents and the fire extinguishing performance of Class B fires are studied, based on the existing fire extinguishing theories and experimental results, the fire extinguishing mechanism of dry water extinguishing agents is discussed.
Research and Practice of Passive Low Energy Residential Design in Rural Areas of Semi-Urbanized Regions in Hot-summer and Cold-winter Zone
Authors: Qin Yuanyuan , Zhou Tiejun
Published: June 2021

The applicability of urban building energy-saving ideas and technologies to rural house deserves reflection. It requires to clarify the key points for rural house energy-saving in theory and practical exploration. Principles of Rural Passive Low Energy Residence should be: passive technology preferred and make full use of local conditions, cope with specific comfort standards and moderately enhance envelope performance, optimize energy supply structure and technical benefits should be obvious with reasonable costs. This paper takes the rural house case study design in Yongsheng Village as an example to carry out the research. Based on the principle of “passive priority and active optimization”, the residential design makes full use of the potential of local microclimate, plane meets the living needs of winter and summer moderately improves the performance of envelope, takes wind tunnel as auxiliary temperature regulation system, and adopts distributed photovoltaic power generation system to provide domestic energy. The practice has achieved good operation results and obvious economic benefits. It provides an engineering example for the implementation of passive low energy technology in rural.
Comprehensive Measuring the Development Level of Water Resources Circular Economy in Beijing-Tianjin-Hebei Urban Agglomeration
Authors: Yang Jing , Jing Ping , Gao Die
Published: June 2021

With the rapid increasing population and rapid economic development, water shortages and water environmental pollution problems have become increasingly prominent. In this paper, based on the concept of circular economy, starting from the four dimensions of water supply, water use, drainage, and regeneration, the comprehensive evaluation index system was established for Beijing-Tianjin-Hebei about water resource circular economy, the entropy weight method is used to determine the index weight, and the weighted comprehensive index method is used to comprehensively evaluate the development level of water resources circular economy. The results show that the development level of water resources circular economy has spatial heterogeneity in 13 cities of Beijing-Tianjin-Hebei from 2012 to 2016, which is in a state of unbalanced development. The utilization of water resources in Beijing and Tianjin is significantly better than that of other cities in Hebei Province. Only Chengde and Qinhuangdao have better water resources recycle in Hebei Province.
Particle Parameters of Asphalt Pavement Milling Recycling Material
Authors: Jing Jing , Fan Liang , Zhou Shengjie , Zhang Chi , Gao WenChen , Zhan Wang
Published: June 2021

Based on laboratory data and literature data, this paper has carried out a study on the particle parameters of asphalt pavement milling recycled materials. From the two indicators of the characteristic particle size and uniformity of the aggregate, the difference between the particle characteristics of the new aggregate and the recycled material, the changes in the composition of the macroscopic particles after the recycled material are extracted in advance and the attenuation law of the asphalt mixture gradation during the service time of the road surface was studied in this paper. The results show that based on the RRS equation, the particle distribution simulation of aggregates, RAP materials and mixtures can be simulated, and two characterization parameters of characteristic particle size and uniformity coefficient can be obtained. Under the condition of the same particle size range, the characteristic particle size of RAP material is smaller than that of the new aggregate, the uniformity improved, and the particle size distribution range becomes narrow. There is a good mathematical relationship between the characteristic particle size and uniformity coefficient of the RAP material after extraction. The characteristic particle size of the RAP material after extraction reduces, while the uniformity coefficient gets further reduced. With the extension of the age, the characteristic particle size and uniformity coefficient of the mixture have shown a significant linear attenuation. In order to ensure the quality stability of recycled mixtures, the classification and management of RAP materials should be strengthened in the actual recycling design and application process.
Study on the Application of Green Environmental Protection Building Materials in Engineering
Authors: Jialei Wang , Hongmin Li , Weiqiong Liu
Published: June 2021

This paper briefly introduces the significance of applying green environmental protection building materials under the background of serious energy consumption and environmental pollution and the current development situation in China. According to the relevant literature and survey data, three restrictive factors in application of green environmental protection building materials are summarized, and some suggestions are put forward.
Study on technical standard of small complete domestic sewage treatment plant
Authors: Jin Huang , Xiaoxin Zhang , Youfeng Sun , Xia Huang , Guanjun Wang
Published: June 2021

This paper expounds the industry and policy background of small complete domestic sewage treatment plant in China, and discusses the basic principles and basic investigation of the development of technical standard for small complete domestic sewage treatment plant, the key technical contents of standard for small complete domestic sewage treatment plant are expounded. Through the development and implementation of this technical standard, it will provide standardized technical support for standardizing and improving the manufacturing level of small complete domestic sewage treatment plants in China.
Research on the Coordinated Development of Resources, Environment, and Economy in the Yellow River Basin
Authors: Zhao Jinhui , Wang Yufeng , Liu Tao , Dong Yiran , Cao Xinyu , Zhang Ting , Zhang Yu , Zhang Lijun
Published: June 2021

The high-quality development in the Yellow River Basin has to be fostered by the coordination of resources, environment, and economy. Therefore, conducting an analysis on the coupling level of resources, environment, and economy in the Yellow River Basin is of major significance to the research on its high-quality development path. The current study focuses on the coupling coordination in the Yellow River Basin. Based on the data of the nine provinces in the Yellow River Basin from 2004 to 2017, a coupling development model is constructed for an analysis of the coupling level in this area and a modeling prediction. A comprehensive evaluation of the development level of resources-environment-economy system and the subsystems in the Yellow River Basin is performed by combining the range change method and entropy weight method. The result shows that despite the rising coupling level of resources, environment, and economy in the Yellow River Basin, the comprehensive evaluation value of the environment subsystem is low, which was merely 0.109 in 2017 and has remained unchanged between 2009 and 2017, resulting in a low coupling coordination degree of resources, environment, and economy. In 2017, the coupling coordination degree only exceeded 0.4. The development was on the verge of imbalance and the high-quality coordinated development of the Yellow River Basin has been restricted.
Influence of refrigerant circuitry arrangement of three-row finned tube evaporator on heat transfer performance under uniform wind speed distribution
Authors: Wang Xue , Wang Ruoyu , Zhang Yu
Published: June 2021

The EVAP-COND software was used to simulate 8 different refrigerant circuitry of the three-row tube heat exchanger under different superheat and outlet saturation temperature conditions. The influence of different refrigerant circuitry on the heat transfer performance of the evaporator was explored. And the influence of superheat and outlet saturation temperature on the evaporator and its changing law were analyzed and discussed. The results show that: Cross arrangement facilitated heat transfer. The dual-flow solution was better than the single-flow solution. And countercurrent arrangement was conducive to heat exchange. The best solution was g, and the worst solution was a. Under the conditions of this study, the heat transfer of curve g was 44.78% and 36.20% higher than curve a, respectively.
Evaluation System of Ningbo’s Water-saving Society Construction under the Digital Economy
Authors: Zhang Yubin , Zhu Huomei , Huang Danxia , Yu Rui
Published: June 2021

In response to the difficulties and problems in the construction of a water-saving society and the construction of a water-saving society in Ningbo in recent years, with rivers as the main canal, the digital economy water-saving society management model was innovatively proposed, and the evaluation index system for social construction was built in the water-saving society, combined with the connotation of the digital economy, a water-saving society evaluation method was put in Ningbo, and suggestions and countermeasures also referred.
Analysis on Improvement Effect of Water Distribution Parameters on River Water Quality
Authors: Lei Hua , Heqin Shang , Qiannan Jin
Published: June 2021

The parameters, such as hydrological condition of the river, location, distributed approach, quantity and quality of water distribution, cann’t be ignored in improving water qualiy of the river. With Liudu River in Yiwu City as a case study, 1-D water hydrodynamic and water quality model was generated to analyze the effect of water distribution parameters on river water quality. The results showed that, the location and distributed approach of water distribution had little influence on the water quality of the river behind the distribution point. Otherwise, concentrated distribution approach was better than dispersive approach, and upstream distribution was better than downstream distribution. The hydrological condition of the river should be considered in the assessment. With the increase of distribution quantity, the improvement effect of the river water quality was increased gradually, but the effect brought by the unit quantity was obviously decreased, the effect brought by the improvement of water quality standed out increasingly.
Multi-Objective Optimization of Efficiency and Pressure Fluctuation for Vertical Inline Pump
Authors: Chen J W , Wang W J , Pei J
Published: June 2021

Vertical inline pump is a single-stage single-suction centrifugal pump. In order to save the installation space, there is a bent pipe before the impeller. In this paper, to achieve efficient and stable operation of the pump, a multi-objective optimization of efficiency and pressure fluctuation on the inlet pipe of vertical inline pump was proposed based on Latin Hypercube Sampling. The geometric shape of an inlet pipe is controlled by the mid curve and the shape of cross section. The fifth-order Bezier curve was adopted to fit the mid curve and a round cross section was set. Totally 7 design parameters of the inlet pipe were selected as design variables, and the pump efficiency and the pressure fluctuation amplitude at the tongue were set as the optimization objectives. 36 groups of sample points were obtained from Latin hypercube sampling (LHS). The results showed that at design flow rate, the efficiency increased from 77.60% to 79.33%. Comparing with prototype, the pressure fluctuation amplitudes of main frequency at two monitoring points were decreased by 0.89% and 9.15%. It was observed that the profile of inlet pipe has an obvious influence on the pump performance and unsteady flow characteristics. Therefore, the profile of inlet pipe will be the key component for the optimization of vertical inline pump, and this study can provide theoretical guidance for researching the hydraulic efficiency and unsteady pressure fluctuation.
Numerical Analysis of reactor coolant pump performance under reverse conditions
Authors: Ran Hongjuan , Qian Xinru , Shi Tianjiao , Wang Dezhong
Published: June 2021

Since no anti-reverse device is equipped in the system of the third generation AP 1000 of nuclear power plant, the reactor coolant pump (RCP) might operate in the reverse condition. However, it is hard to carry out the experiments of RCP in reverse condition due to its high temperature and special thrust bearing (their thrust bearing may not afford the reverse condition either). Hence, CFX with unsteady RANS turbulence model is employed to thoroughly study the characteristics of the reactor coolant pump in reverse pump mode as well as the normal pump condition. Their different flow patterns between the normal case and the reverse case are compared. It is found that a beat frequency captured in the impeller in the reverse case is suggested to be the diagnostic signal of the generation of reverse condition.
Theoretical Turbine Model with Hydraulic Losses
Authors: Svingen B , Reines A F , Nielsen T K , Storli P T
Published: June 2021

When doing transient and dynamic analysis of powerplants, a mathematical representation of the turbine is needed. These models can be fully based on empirical data, or they can be based on a first principles approach. A first principles approach is practical in many circumstances because any known and unknown turbine can be modelled, and the model can easily be simplified and linearized without losing generality or physical correctness. The model can be used for general transient studies, also where the turbines are not yet specified, or when doing control system analysis and analysis of the grid.

Using the Euler turbine equations together with the definition of the turbine opening degree, one obtains a model that is geometrically and physically correct. The development of this model started several years ago, and this paper presents the current development. The model shows good agreement of the efficiency as a function of speed, as part of the Euler turbine equation. However, the efficiency as a function of flow is over predicted because hydraulic loss phenomenon such as turbulence and dissipation are not inherently included. There are several ways to include the hydraulic losses. This can be done in a simplified manner, or more elaborate, which also could involve empirical relations for exact fit with a measured turbine. This paper discusses these possibilities, along with some examples.
Hydraulic Design Challenges of High Head 880 MW Gouvães Pumped-Storage Power Plant
Authors: Nicolet C , Landry C , Richter W , Vera Rodriguez J C , De la Torre Abietar L , Zenz G
Published: June 2021

The 880 MW pumped-storage power plant of Gouvães, which is part of the Alto Tâmega hydro power scheme from Iberdrola is currently under construction in the north of Portugal. The power plant is equipped with 4 reversible Francis pump-turbines with a gross head of 660 m. The power plant features several challenges with respect to the hydraulic design such as: i) ultra-high-head single stage reversible Francis pump-turbine of very low specific speed leading to severe hydraulic transients, ii) a long high-pressure penstock, iii) an headrace differential surge tank linked to a 4700 meters long headrace tunnel and iv) a complex tailrace differential surge tank linked to a 700 meters long tailrace tunnel. To perform the hydraulic design of the pumped-storage power plant, a stepwise approach presented in the paper was undertaken by Iberdrola. A detailed 1D hydraulic transient analysis was performed to optimize the headrace and tailrace surge tank dimensions. Then a combined CFD and reduced scale physical transient tests of both surge tanks was conducted. This enabled to address the complex 3D flow physics that develop in surge tanks but are not captured by 1D transient simulations such as free surface, upsurges against walls, verification of throttle singular head losses and effects not captured by 3D CFD such as air-water mixture and detection of air entrainment risk.
Application of a General Discrete Adjoint Method for Draft Tube Optimization
Authors: Fleischli B , Del Rio A , Casartelli E , Mangani L , Mullins B F , Devals C , Melot M
Published: June 2021

Automatic optimization is becoming increasingly important in turbomachinery design to improve the performance of machine components and Evolutionary Algorithms (EAs) play a very important role in this task. The main drawback of EAs is the large number of evaluations that are required to obtain an “optimal” result. Consequently, in order to keep the computational time in an affordable frame for design purposes, either the mesh size has to be limited, thus reducing the resolution of the flow phenomena, or the number of free parameters must be kept small. Adjoint optimization does not suffer from these restrictions, i.e. the optimization time is not affected by the number of parameters. The computational effort for the adjoint method scales only with the grid size and is usually in the range of two times the CFD simulation alone. In this paper, a discrete adjoint method based on a coupled pressure based RANS solver is presented and applied to draft tube optimization. The adjoint solver is general and can therefore deal with any turbulence model supported by the CFD solver as well as any boundary condition, including mixing planes and mesh interfaces needed for multi-stage simulations. Furthermore, there is no restriction on the choice of objective function. The adjoint method is first applied to a baseline draft tube geometry and then again to its EA optimized geometry where the objective function was the minimization of losses in the draft tube. To reduce the complexity for this proof of concept but still including multiple operating points in the optimization, only peak efficiency and full-load were optimized simultaneously. The adjoint optimization can significantly improve the draft tube performance in both cases (baseline and EA optimization). The interplay between local and global optimization seems to be a promising strategy to find optimal geometries for multi-operating point/multi-objective optimization and will be further investigated in subsequent research.