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Copyright of Railway Standard Design is the property of Railway Standard Design Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objectives: Latest release of international terrestrial reference frame has been generated with an enhanced modeling of nonlinear station motions, while more investigations on the strategies applied for the terrestrial reference frame modeling nonlinear station motions still needed. Methods: A global GPS (global positioning system) network has been reprocessed, using the latest GNSS (global navigation satellite system) data processing models and an integrated strategy, and then accurate and consistent input data are obtained; the post-seismic deformation models of 13 CMONOC (crustal movement observation network of China) stations are established and used as the input data, and FREQ2016 based on the function model, and GFZ2016 and EOST2016 considering the environmental loading correction are realized; these GPS terrestrial reference frames with different models are compared in terms of the goodness for fit, velocities and seasonal signals, and then the optimal model is explored. Results: The results show that the weighted root mean square averages of the postfit residuals of FREQ2016 are smaller than those of GFZ2016 and of EOST2016; FREQ2016 shows more significant seasonal signals, especially for semi-annual signals; the horizontal velocity field differences of these three are almost negligible (<0.08 mm/a), and the large vertical velocity differences, for some stations, reach 1.3 mm/a; the reduction of FREQ2016 horizontal velocity formal errors is about 10%. Conclusions: This paper suggests that the strategy based on the function model is better than that of considering the environmental loading correction. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Geodesy & Geodynamics (1671-5942) is the property of Editorial Board Journal of Geodesy & Geodynamics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

At present, the problems of energy depletion and environmental pollution caused by non renewable energy such as oil and coal have seriously hindered the sustainable development of our society. Biomass energy is a reliable low-carbon alternative energy with renewable, clean and other characteristics. Therefore, the energy transformation to renewable energy is crucial to China's development. Research shows that China has rich biomass resources. For example, agricultural wastes can be used to produce biogas by anaerobic fermentation of agricultural wastes straw, which can reduce a lot of carbon emissions. Therefore, it is of great significance for China's development to make full and reasonable use of this resource. This paper discusses two types of biogas power generation technologies using straw as raw material, namely, traditional biogas direct combustion power generation technology and biogas fuel cell power generation technology. Based on life cycle assessment (LCA) and time value dynamic analysis method, the feasibility of two types of biogas power generation technologies is comprehensively evaluated from both environmental and economic aspects. The feasibility of this technology is compared with that of coal-fired power generation technology, and the feasibility of straw biogas power generation technology in both economic and environmental aspects is discussed. In the feasibility analysis of environmental benefits, three potential values of environmental impact categories are considered: global warming (GWP), environmental acidification (AP) and human toxicity (HTP). The environmental impact potential of the three power generation technologies is calculated according to the equivalence factor of each environmental category. After the environmental impact potentials are standardized, the total environmental impact loads of different environmental categories are obtained. The analysis of the total environmental impact is consistent with the judgment of the environmental benefits of the three power generation technologies. The economic feasibility analysis adopts the dynamic analysis method of time value, and selects the dynamic investment payback period, internal rate of return and net present value as the analysis indicators. According to literature review, find representative power plants, and calculate dynamic payback period, net present value and internal rate of return by referring to capital input and output data of power plants. According to the calculation results, the economic feasibility of different power generation technologies is comprehensively analyzed. The results show that the biogas fuel cell power generation technology is the best in terms of total environmental impact, and the total environmental impact load is 8.55×10-4, followed by biogas direct combustion power generation technology, with a total environmental impact load of 2.15×10-2。 Compared with coal-fired power generation technology (2.97×10-1), the emission reduction rate reached 99.71% and 92.76% respectively. In terms of economic benefits, when the dynamic payback period and NPV are taken as indicators, the payback period of the straw biogas direct fired power generation project is the shortest (12.03 years), the NPV in the operation period can reach 1 361 246 Yuan/MW, and the economic benefits are the best; The second is coal-fired power generation project (14.5 years), with a net present value of 423 933 Yuan/MW; The dynamic payback period of biogas fuel cell power generation project is more than 20 years, and there is no surplus during operation. Therefore, compared with biogas fuel cell power generation technology, biogas direct combustion power generation technology has more significant economic benefits. This shows that biogas direct fired power generation technology will remain one of the best power generation technologies to replace coal-fired power generation in the future. [ABSTRACT FROM AUTHOR]

Copyright of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Based on the comprehensive calculation of CORS network, this paper uses the load field removal‐ recovery technology to study the crustal vertical deformation and ground gravity spatio ‐ temporal changes caused by environmental load in Wenzhou ‐Lishui region and compares it with GRACE gravity satellite results. Some conclusions are drown as follows: ① The effects of environmental load on the vertical deformation and gravity change of crust are up to the centimeter and ten micro ‐gauge levels, respectively, and the seasonal variation characteristics are significant. ② The vertical deformation and gravity change in winter show a decreasing and increasing trend from west to east, respectively. ③ Compared with GRACE results, in addition to local region differences, the overall trend of spatiotemporal changes has a higher consistency. ④ The CORS network can monitor the spatiotemporal changes of crustal vertical deformation and gravity field caused by total surface environmental load. The research methods and results of this paper can provide an important reference for environmental dynamics research and geological disaster monitoring and early warning. [ABSTRACT FROM AUTHOR]

To understand the agricultural production dynamics and sustainability in the hilly areas of southeast China, this paper took Dehua county, a typical mountainous area in Fujian province, as an example to quantitatively analyze the changes of input, output, environmental load and sustainability of farmland-livestock systems from 2007 to 2016, and constructed the indicators of waste emergy ratio and environmental pollution emergy negative output. The results showed that the input of the farmland- livestock system in the study area was mainly based on the purchasing emergy, accounting for 68%-79% of the total emergy input, and the emergy of water resources accounted for 21%-31%. The emergy output of livestock systems accounted for more than 72% of the total output. And the emergy density fluctuated between 2.68×1012 and 3.33×1012 sej·m-2, and emergy per person increased from 1.23×1016 sej to 1.72× 1016 sej. The net emergy yield ratio decreased by 40%, and the environmental load increased significantly, which could have been maintained since 2015. The emergy sustainability index fell rapidly from 1.14 to 0.42 after a brief rise in 2007-2010. From the indicators of construction, the proportion of system waste emergy decreased, and environmental pollution emergy output decreased by about 22%. In terms of comprehensive economic benefits and waste utilization, the sustainable development of Dehua county has gradually improved in recent years. Dehua county is currently adjusting its output structure of farmland- livestock system. It should increase the amount of feedback emergy in the system, control fertilizer and feed input, and improve waste utilization to achieve sustainable development. [ABSTRACT FROM AUTHOR]

Copyright of Engineering Mechanics / Gongcheng Lixue is the property of Engineering Mechanics Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The environmental loads such as wind, wave, flow onto drilling rig and mooring system of the HaiYangShiYou 981 are analyzed according to the actual working condition in South China Sea. The Haiyang Shiyou 981 drilling rig is chosen as the research object for mooring positioning system. The 3D model of the platform is established first by using the AQWA software to simulate and analyze the motion response of the drilling device under the action of wave load. As the deep water drilling rig is fixed in the sea with twelve anchors which are symmetrical distribution, the influence of top pretension angle on dynamic response of mooring system and motion response of drilling rig under different environmental load is analyzed by changing the inclination angle of the pretension at the top of the drilling rig.

Large-diameter steel casing is widely used as pile-foundation during design and construction of open sea bridges, and its wave force problem is one of hot issues in ocean engineering. Most of the existing results are based on numerical simulations and model tests, however results on in-situ monitoring are fewer. Relying on" One Belt One Road" landmark project China-Maldives Bridge, we installed multiple sets of pressure sensors on No.20 pier column of main bridge, and carried out field monitoring of environmental loads. The methods of Fast Fourier Transform and filtering are adopted to analyze measured data, separate the different frequency components, convince the period of tide and extract wave pressure which the maximum wave pressure is about 4 kPa. The according conclusion is of great significance for the design of temporary structures. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Agro-Environment Science is the property of Journal of Agro-Environment Science Editorial Board and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Hebei University of Science & Technology is the property of Hebei University of Science & Technology, Journal of Hebei University of Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Submarine pipelines are regarded as the lifeline of sub-sea oil and gas transmission, and natural frequency of free span is a key factor for evaluating its dynamic response condition. Soil property which is used to establish analytical model of free span pipeline can be simulated by means of altering dynamic stiffness of soil spring. Based on the proposed model, the fundamental vibration characteristics are studied. The effects of various factors, such as soil property, external environmental load, axial force and span length on natural frequencies are discussed in detail. The results show that span length has the largest effect on natural frequencies and the frequencies have different features corresponding to different factors. [ABSTRACT FROM AUTHOR]