bluuebunny/crossref_metadata_2025_split huggingface dataset:
An investigation of planetary nebulae accompanying PG 1159 central stars, based on Gaia DR2 measurements
Authors: Ali Alaa , Alharbi Wedad R. 
Published: August 2021

Abstract
This article discusses the physical and kinematical characteristics of planetary nebulae accompanying PG 1159 central stars. The study is based on the parallax and proper motion measurements recently offered by the Gaia space mission. Two approaches were used to investigate the kinematical properties of the sample. The results revealed that most of the studied nebulae arise from progenitor stars in the mass range 0.9–1.75 M
⊙. Furthermore, they tend to live within the Galactic thick disk and move with an average peculiar velocity of 61.7 ± 19.2 km s−1 at a mean vertical height of 469 ± 79 pc. The locations of the PG 1159 stars on the H-R diagram indicate that they have an average final stellar mass and evolutionary age of 0.58 ± 0.08 M
⊙ and 25.5 ± 5.3 × 103 yr, respectively. We found a good agreement between the mean evolutionary age of the PG 1159 stars and the mean dynamical age of their companion planetary nebulae (28.0 ± 6.4 × 103 yr).
Errors and uncertainties associated with the use of unconventional activity data for estimating CO2 emissions: the case for traffic emissions in Japan
Authors: Oda Tomohiro , Haga Chihiro , Hosomi Kotaro , Matsui Takanori , Bun Rostyslav 
Published: August 2021

Abstract
CO2 emissions from fossil fuel combustion (FFCO2) are conventionally estimated from fuel used (as activity data (AD)) and CO2 emissions factor. Recent traffic emission changes under the impact of the COVID-19 pandemic have been estimated using emerging non-fuel consumption data, such as human mobility data that tech companies reported as AD, due to the unavailability of timely fuel statistics. The use of such unconventional activity data (UAD) might allow us to provide emission estimates in near-real time; however, the errors and uncertainties associated with such estimates are expected to be larger than those of common FFCO2 inventory estimates, and thus should be provided along with a thorough evaluation/validation of the methodology and the resulting estimates. Here, we show the impact of COVID-19 on traffic CO2 emissions over the first six months of 2020 in Japan. We calculated CO2 monthly emissions using fuel consumption data and assessed the emission changes relative to 2019. Regardless of Japan’s soft approach to COVID-19, traffic emissions significantly declined by 23.8% during the state of emergency in Japan (April–May). We also compared relative emission changes among different estimates available. Our analysis suggests that UAD-based emission estimates during April and May could be biased by −19.6% to 12.6%. We also used traffic count data for examining the performance of UAD as a proxy for traffic and/or CO2 emissions. We found the assumed proportional relationship between traffic changes and CO2 emissions was not enough for estimating emissions with accuracy, and moreover, the traffic-based approach failed to capture emission seasonality. Our study highlighted the challenges and difficulties in repurposing data, especially ones with limited traceability/reproducibility, for modeling human activities and assessing the impact on the environment, and the importance of a thorough error and uncertainty assessment before using these data in policy applications.
Time to better integrate paleoecological research infrastructures with neoecology to improve understanding of biodiversity long-term dynamics and to inform future conservation
Authors: Nieto-Lugilde Diego , Blois Jessica L , Bonet-García Francisco J , Giesecke Thomas , Gil-Romera Graciela , Seddon Alistair 
Published: August 2021

Abstract
Anthropogenic pressures are causing a global decline in biodiversity. Successful attempts at biodiversity conservation requires an understanding of biodiversity patterns as well as the drivers and processes that determine those patterns. To deepen this knowledge, neoecologists have focused on studying present-day or recent historical data, while paleoecologists usually study long-term data through the composition of various biological proxies and environmental indicators. By establishing standard protocols or gathering databases, research infrastructures (RIs) have been instrumental to foster exchange and collaboration among scientists within neoecology (e.g. Global Information Biodiversity Facility or National Ecological Observatory Network) and paleoecology (e.g. Paleobiology Database, Neotoma Paleoecology Database or European Pollen Database). However, these two subdisciplines (and their RIs) have traditionally remained segregated although both provide valuable information that combined can improve our understanding of biodiversity drivers and underlying processes, as well as our predictions of biodiversity responses in the future. For instance, integrative studies between paleo- and neoecology have addressed the global challenge of biodiversity loss by validating climate and ecological models, estimating species fundamental niches, understanding ecological changes and trajectories, or establishing baseline conditions for restoration. Supporting and contributing to research infrastructures from both paleo- and neoecology, as well as their further integration, could boost the amount and improve the quality of such integrative studies. We argue this will enable improved capabilities to anticipate the impacts of global change and biodiversity losses. To boost such integration and illustrate our arguments, we (1) review studies integrating paleo- and neoecology to advance in the light of global changes challenge, (2) describe RIs developed in paleoecology, and (3) discuss opportunities for further integration of RIs from both disciplines (i.e. paleo- and neoecology).
The Exploratory Research on Reform and Innovation of Project Management in Grid Enterprises under the Changing Circumstances
Authors: Xu Haiqing , Yan Huaguang , Deng Chunyu , Kang Jiandong , Li Junhui , Han Xiao 
Published: August 2021

Abstract
At present, the management systems and enterprises demand have already changed because of the environments-changing, which puts new requirements and directions for grid enterprises. This research comprehensively analyzes the current situation and problems of the project management, and then explores the profound impact of the new situation to the project management system in power grid enterprises. After that, this research also summarizes the reforms and innovation experiences of the power grid enterprises in the project management, and extracts the project management characteristics of the grid enterprises under the new situation. At the same time, based on the project management practices, we provide a new method and implementation path for grid enterprises. This method and path provide theoretical and methodological support for relevant grid enterprises to improve their management efficiency and improve organizational performance.
Application of Thermoelectric Technology in Direct Air Cooling System of Thermal Power Plant
Authors: Zhang Xuhui , Zhang Xinwang 
Published: August 2021

Abstract
In recent years, with the improvement of the coefficient of merit of thermoelectric materials, the research of thermoelectric power generation has entered a new climax. The developed countries have listed the development of thermoelectric power generation technology into the medium and long-term energy development technology. The research on thermoelectric power generation in China started relatively late, mainly focusing on the theory and preparation of thermoelectric materials. At present, the field of semiconductor thermoelectric power generation is just introduced, and its practical application is still blank. Thermal power generation technology is used to recover waste heat from direct air cooling system of thermal power plant. Power supply of wireless temperature sensor can be realized through energy storage components or integrated power management system, which can reduce energy waste and environmental pollution. It is of great significance for industrial waste heat recovery and clean energy development.
Research on Construction Methods of Transient Security Region of AC/DC Hybrid Power Grid
Authors: Zongze Yu , Zishuo Li , Fengchang Sun , Changhai Miao 
Published: August 2021

Abstract
In order to study the AC/DC hybrid system transient stability assessment methods, this article is based on the New England 10 machine 39 node communication system after modification of AC/DC mixed system, the use of PSD - BPA software, to pure AC system and AC/DC hybrid system of AC busbar three-phase short-circuit fault transient stability of the numerical simulation analysis, and uses Matlab to solve its active power injection space transient security region.
Research on the activity level of key diesel trucks in Tianjin based on the access control system
Authors: Xiaoqing You , Jiguang Wang , Su Li , Zhiwen Yang , Zhenkai Xie , Jinchao Chen 
Published: August 2021

Abstract
Through the installation of an access control system for key vehicle enterprises in Tianjin, the real-time monitoring of heavy-duty diesel vehicles in use by key enterprises in Tianjin is carried out, and the information of heavy-duty diesel vehicles in Tianjin is counted, and the activity level is analyzed. The results show that the proportion of heavy-duty diesel vehicles used by key enterprises in Tianjin is about 10%; foreign vehicles accounted for 50%, of which Hebei accounted for 71%, most of which came from Tangshan City and Cangzhou City, accounting for 32% and 14% respectively; the change cycle of traffic flow is M-shaped, the peak of traffic flow is 9:00 and 16:00, and it is relatively stable at night; during the Spring Festival and the heavy pollution supervision period, the traffic volume decreased significantly by 50% and 30% respectively. The research of activity level can get the structure and use status of heavy-duty diesel vehicles in Tianjin, and provide effective data for emission inventory simulation and pollution control research.
The SWOT Analysis and Countermeasure Research on the Development of Wind Power Industry in China
Authors: Liu Yundan , Wang Jin 
Published: August 2021

Abstract
Under the dual pressures of conventional energy emergency and deterioration of the ecological environment, wind energy as a renewable clean energy is valued. Wind power has developed rapidly, and economic advantages have gradually become prominent. This paper analyses the development status of wind power industry in China, and the internal and external factors that affect the development of wind power industry are analyzed by using SWOT model. Research shows that the development of wind power industry is facing the bottleneck of independent research and development, technical barriers, benchmarking difficulties. This paper puts forward four strategies to get rid of the current dilemma and promote the healthy development of this industry, which is SO strategy— intensify the development, ST strategy— optimize the adjustment, WO strategy— handle the solutions to the toughest problems, WT strategy— strengthen the industrial development.
Research and application of old well evaluation technology in underground gas storage
Authors: Yi Zhang , Gaofeng Li , Weiyi Xie , Wei Rong , Jun Li , Dong Yang , Shufen Ma , Yuting Guo 
Published: August 2021

Abstract
Gas storage has high requirements for new drilling well structure, cementing quality and wellbore quality. In order to ensure the sealing of the wellbore, cement is returned to the surface and special casing is used to ensure the sealing of the wellbore. Production Wells of crude oil reservoirs generally cannot meet these conditions for the gas storage converted from depleted oil and gas reservoirs. Therefore, production Wells will not be used in principle after the reconstruction of the gas storage. In order to improve the comprehensive economic benefit and reduce the construction cost, these production Wells are generally used as monitoring Wells, observation Wells and gas production Wells after quality review and evaluation. This paper introduces the research and application of quality review, detection technology and evaluation technology of old Wells in underground gas storage.
Research on the adjustment boundary of well pattern injection-production structure in the eastern area of South Second District
Authors: Ning Ma 
Published: August 2021

Abstract
Since the “Eighth Five-Year Plan”, the practice of extracting fluid from low-water-cut wells and controlling fluid from high-water-cut wells has controlled the increase in water cut and the growth rate of fluid production, and achieved the goal of stabilizing oil and water. At present, the water cut of each well pattern is basically close, and the potential for structural adjustment is small. The effect of continuing to adhere to the previous adjustment of injection-production structure is not obvious. It is necessary to revise the injection-production structure adjustment policy to achieve balanced production of various oil layers and control production decline.
Permeability variation of sandstone under different water pressures after unidirectional heating
Authors: Xin Lin , Han Limin , Feng Mingze , Li Kaixuan , Wu Jing , Li Jiaze 
Published: August 2021

Abstract
In the process of Underground Coal Gasification (UCG), the permeability of rock around coal seam will change after high temperature. In order to investigate the influence of UCG and groundwater level change on groundwater seepage, an experimental study on permeability change of sandstone under unidirectional heating under different water pressures was carried out. Taking unidirectional heating sandstone as the research object, confining pressure, axial pressure and different water pressure are set to simulate different water pressure environment, and permeability changes are obtained through experiments. The results show that: water pressure has an effect on the permeability of S01, but the permeability does not increase with the increase of water pressure. Under certain stress conditions, there is such a region in S01. When the water pressure is in the region, it has little or even negative effect on the improvement of rock permeability. When the water pressure is not in the region, it has significant effect on the improvement of rock permeability. Through the fitting of permeability and water pressure, it is concluded that the permeability of S07 increases linearly with water pressure, and the permeability of S05 increases nonlinearly with water pressure.
Simulation of creep deformation of faced rockfill dam based on secondary development of ABAQUS
Authors: Chen Hui , Zhang Yanyi 
Published: August 2021

Abstract
The creep deformation of concrete face rockfill dam is one of the key factors affecting the safety and performance of a concrete faced rockfill dam. In this paper, creep deformation process was carried out by secondary development based on ABAQUS software. A concrete faced rockfill dam in Laos is the research object of long-term deformation inversion. The calculated results are in good agreement with the measured analysis results. The proposed method can provide reference for the long-term deformation of earth-rockfill dam.
Research on the Evaluation Method of the Deviation of the Horizontal Tail Cathedral Angles and the Engine Installation Angles in the Leveling and Measurement of Civil Aircraft
Authors: Xian Hui , Cong Ding , Juan Cao 
Published: August 2021

Abstract
The leveling and measurement of the aircraft is performed after the final assembly is completed. Measurements are used to check the accuracy of the geometric relationships within and between the various components of the aircraft and checks whether the aircraft assembly meets the overall design requirements. It is performed on the datum marks of the level measurement. During the leveling and measurement of a certain type of aircraft, the horizontal tail cathedral angles, and the engine installation angles of many aircraft have been found to have different degrees of deviation. These deviations have impact on aerodynamic characteristics, stability performance, and on-site production schedule of the aircraft. This paper has carried out special research on this deviation of the horizontal tail cathedral angles and the engine installation angles, by using empirical formulas and other methods to evaluate the deviation of the leveling and measurement, to provide a basis for the deviation evaluation of the leveling and measurement, improve the evaluation efficiency, and ensure the aircraft mass production. In addition, this paper also summarizes the root causes of the deviation, and provides an improvement direction for the aircraft’s configuration control, fuel consumption reduction and carbon dioxide emission reduction.
Sustainable Agriculture and Food Production in Qinghai: Analysis based on grey correlation model
Authors: Meili Jiang 
Published: August 2021

Abstract
The sustainable development of agriculture requires continuous improvement of comprehensive agricultural capabilities on the one hand, and continuous improvement of land productivity on the other hand to ensure a sustainable increase in food production capacity. At present, China is facing the “tight balance” situation of supply and demand for food security in the medium and long term. The land productivity of agriculture in Qinghai is low, and the grain production capacity is difficult to guarantee the security of food supply in Qinghai Province. Based on the relevant theories of sustainable agricultural development, this article analyzes the factors affecting land productivity in Qinghai Province, and uses grey correlation analysis to analyze the correlation effects of sustainable agricultural development factors on land productivity. If only the sustainable development of agriculture is pursued, land productivity cannot be improved, which will lead to low grain production capacity and unsustainable development of supply level and quality. In the conclusion, this article puts forward relevant suggestions for improving food security in Qinghai Province.
Research on the spatial perception evaluation of settlement streets based on the concept of sustainability
Authors: Zhou Qianlan 
Published: August 2021

Abstract
Nowadays, the perception of the street space environment in urban residential areas is receiving more and more attention, and a sick urban space environment can make environmental participants feel their safety is threatened. By redesigning the street space environment, the safety of the street and the perception of the environment can be improved. Taking Guitang Road as a typical residential street in Yuhua District of Changsha City, we use Depthmap software to analyze the degree of connectivity, integration and selection of street axes, and apply the reliability validity test, principal component analysis and multiple linear regression analysis in SPSS software based on the statistical results of the questionnaire to quantitatively study the statistical data and explore the main physical Environmental factors. Based on the six categories of spatial elements in CPTED theory, we propose a design strategy to reduce the fear of victimization in residential street space, so as to improve the street space environment and sustainable development. The aim is to promote urban planning and environmental sustainability to carry each other, in order to make urban planning diverse and stable through rational planning and construction of new environmental elements.
Assessment of water footprint for crop production: a case study in North China
Authors: Wang Chunxiao , Zhao Jing , Tian Baochuan 
Published: August 2021

Abstract
In this study, green water footprint (GWF), blue water footprint (BWF) and total water footprint (WF) of five crops (i.e., wheat, maize, cotton, groundnut and beans) for ten subareas in North China are calculated. The spatial distribution of GWF, BWF and WF are analysed and results that different crop in different subareas have different GWF, BWF and WF. Due to the uneven precipitation, the contribution of GWF to WF is lower than BWF in winter and higher than BWF in summer. Moreover, cotton has the highest average value of WF (5.3579 m3/kg), then beans (1.4266 m3/kg), groundnut (1.069 m3/kg), wheat (0.7499 m3/kg). Maize has the lowest average value of WF (0.5695 m3/kg). It is suggested that the cultivated area of maize with the lowest WF should be expanded and the cultivated area of cotton with highest WF should be reduced. The results can help reduce water footprint of crops to ensure food security and alleviate water shortages.
Numerical Simulation of Wind Waves and calculation of planning wave factors in the East Taihu Lake, Jiangsu Province, China
Authors: Jun Chen , Fan Zhu , Xiang Lin 
Published: August 2021

Abstract
Taihu Lake is a large shallow lake in the lower Yangtze River Delta. The wave action in Taihu Lake plays an important role in coastal port construction. In this paper, based on the 10 min average wind speed at 10 m above the water surface recorded hourly from August 14 to August 17, 2014, the SWAN wave model is used to simulate the wind waves of the Taihu Lake in the corresponding period. Due to the lack of long-time series of wave observation data in the project area, the relationship between design wind speed and wind wave is used to calculate wave elements in different return periods. The results show that the strong wind direction and strong wave direction of the East Taihu Lake are NNW. The waves in the proposed Qidu harbor are mainly from the waves outside the permeable breakwater. Under the action of the most unfavorable wave direction NE, the effective wave height of most waters in the harbor is below 0.4m, which can meet the requirements of avoiding waves for fishing boats.
Short-term forecast of Yangtze River water level based on Long Short-Term Memory neural network
Authors: Chen Shinan , Qiao Yunkai 
Published: August 2021

Abstract
The water level fluctuation forecast of Yangtze River plays an important role in the navigation planning and other areas. This study used LSTM neural network to make short term forecast of the water level of Nanjing navigable river, focusing on the 2 days, 3 days and 5 days-forecast from the past 14 days. The error of mean square reached 0.064, 0.121 and 0.195, showing a rather accurate prediction. The model was also suitable for longer time series prediction. This study optimized the model by adjusting the hyper-parameters using qualitative and quantitative analysis and further decided that the batch size equals to 90 and the epoch equals to 250 in the case of 5 days-forecast from the past 14 days. The prediction accuracy increased by 21% with a good prediction performance, and the error of mean square was reduced to 0.153. It provided a reference for the selection of hyper-parameters for the prediction of water level in Nanjing station by LSTM neural network.
Temporal and Spatial Variation of water quality in the Yongding River Basin
Authors: Xie Ying , Jinjin Ge , Guo Yue , Peng Wenqi , Wang Liming 
Published: August 2021

Abstract
For exploring the water quality and macroinvertebrate community characteristics of the Yongding River Basin, investigation of water environment and macroinvertebrates was conducted in 34 sampling sites in August 2016 and April 2017. Furthermore, Water Quality Index (WQI) and biological index (BI) were used to assess the water quality of studied rivers. According to the water quality evaluation results of the WQI and the BI method, the water quality of most sites in non-flood season were equal to or better than those in flood season, and these sites were mostly located in urban area. The dominant land use and non-point source pollution was the primary contributor to water quality degradation in rural areas. There are both similarities and differences between BI index and water quality identification index. From the evaluation results of Sanggan River, Yanghe River and Yongding River, the water quality of Yanghe River is better than that of Sanggan River and Yongding River.