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Rivers are important carriers of water transmission, water supply, and water nourishment, and the virtuous cycle of their ecosystems is directly related to the degree of completion of the construction of ecological civilization and the high-quality development of the national economy. From the perspective of symbiosis theory, this paper constructs a river health value assessment index system and analyzes the symbiotic synergistic effect of nine provinces in the Yellow River Basin in China from 2000 to 2020 by using a logistic symbiosis evolution model. Health values at the Yellow River Basin scale and the provincial administrative area scale were also analyzed, and it was found that (1) the Yellow River Basin experienced a period of sub-par river health in the past, but with the implementation of ecological protection and high-quality development strategy in recent years, the health of the river showed an trend of improvement during the period of 2017–2020; (2) at the provincial administrative scale, the Yellow River Basin has significant differences, which are manifested in the obvious differences between provinces in terms of the functional value of river health provision and the economic functional value. In order to reduce the regional differences, it is recommended that the provinces work together and give full play to their own characteristics and strengths in the management of the watershed, so as to make up for the weaknesses of regional development and realize the synergistic development of the watershed; and (3) in terms of symbiosis level, rivers in the Yellow River Basin generally show parasitic relationships, and most of them exhibit natural ecological diversity and competitiveness with socio-economics. Therefore, a more comprehensive consideration of the balanced development of each function is needed in river health management in the future to achieve integrated watershed health. These results suggest that the development of river ecological health in the Yellow River Basin requires the joint efforts of the whole of society as well as regional synergy and integrated management at the policy level to achieve more sustainable and balanced watershed development. [ABSTRACT FROM AUTHOR]

The shortage of water resources has seriously restricted the sustainable development of China's economy. Contracted water-saving management (WSMC) has emerged as an important measure to effectively alleviate this problem. However, the rationality and fairness of benefit allocation affect the stakeholders' enthusiasm for participating in the project. The lack of a water-saving benefit allocation scheme is one of the critical obstacles hindering the implementation and promotion of the project. This study identifies the core stakeholders in WSMC projects in Field-project in an irrigation district. Then, with comprehensive consideration of the importance, cost input, risk-taking, and effort of each participant, we examined the benefit allocation scheme in the WSMC projects of Field-project in an irrigation district by building a model based on Nash Equilibrium, Shapley value method, and modified Shapley value method. We found that the case in which the WUA E implements the WSMC project alone yields the lowest total revenue of the schemes considered, and each participant's benefit is also at the lowest. Nash Equilibrium can achieve the maximum expected return for both participants. With the Shapley value method, the WUA E earns the largest benefits, accounting for 57.5% of total revenue, followed by the WSSE D. Under the calculation principle of the modified Shapley value model, the WUA E's benefit decreases significantly, implying that the revenues previously earned by the WUA E are transferred to the WSSE D. This result is due to the below-average levels of importance, cost input risk-taking, and effort for WUA E in the project. It can be seen that the modified Shapley value method is more suitable for benefit allocation of the WSMC project of Field-project in an irrigation district. Finally, a typical case study in China on a shared WSMC project of Field-project in an irrigation district showed how the proposed method works. Then, we proposed policy implications for promoting project implementation from three perspectives: stakeholders, income distribution, and risk management, and identified the limitations of the research and outlined the future research directions. [ABSTRACT FROM AUTHOR]

To improve the efficiency of estimation of deriving OTLD parameters with higher accuracy and take full advantage of multi-GNSS data, we investigate the potential of using global ocean tide model predictions as prior constraint for GLONASS and combined GPS+GLONASS kinematic precise point positioning (PPP), analyzing one year of GPS and GLONASS data from 20 Crustal Movement Observation Network China (CMONC) sites distributed along China coast. Seven global ocean tide models predictions are employed as prior constraint in kinematic PPP. Compared with the results of GPS-only kinematic PPP with priori information constraint, the result shows that GPS+GLONASS and GLONASS can improve the accuracy of OTLD estimates more than 40% in three components over GPS. The comparison of the effect of OTLD estimates on long-period signals in position time series shows that the correction effect of the kinematic PPP with seven different priori information constraint estimates is all as same as the reference model in three components. [ABSTRACT FROM AUTHOR]

Sonodynamic therapy (SDT) induces reactive oxygen species (ROS) to kill tumor cells. Heme oxygenase-1 (HO-1), as an important antioxidant enzyme, resists killing by scavenging ROS. Zinc protoporphyrin (ZnPP) not only effectively inhibits HO-1 activity, but also becomes a potential sonosensitizer. However, its poor water solubility limits its applications. Herein, we developed an improved water-soluble method. It was proved that pegylated zinc protoporphyrin-mediated SDT (PEG-ZnPP-SDT) could significantly enhance ROS production by destroying the HO-1 antioxidant system in ovarian cancer. Increased ROS could cause mitochondrial membrane potential collapse, release cytochrome c from mitochondria to the cytoplasm, and trigger the mitochondrial–caspase apoptotic pathway. In conclusion, our results demonstrated that PEG-ZnPP-SDT, as a novel sonosensitizer, could improve the antitumor effects by destroying the HO-1 antioxidant system. It provided a new therapeutic strategy for SDT to treat cancers, especially those with higher HO-1 expression. [ABSTRACT FROM AUTHOR]

Brittleness is a crucial parameter for assessing the mechanical behavior of rocks, including fracturability, drillability, and rockburst tendency. The ubiquitiform geometry has been widely used to describe complex fine structures due to its advantages including the distribution of fragment size, energy dissipation patterns, and crack branching. In this study, a new method is proposed to evaluate the brittleness characteristics of rock from the perspective of fragmentation pattern using ubiquitiformal complexity. The uniaxial compression tests were conducted on tuff and slate samples with different L/D ratios (ranging from 0.3 to 1.5) at four strain rates (0.0005, 0.001, 0.005, and 0.008 s−1) to investigate the fragmentation pattern and brittleness behavior of rocks. The relationship between ubiquitiformal complexity and brittleness index is analyzed to evaluate the failure behavior of rock using the ubiquitiform theory. The results indicate that the criterion that considers the post-peak phase of the stress-strain curve is more accurate compared to others. The brittleness indexes B1 and B3 increase with the strain rate, whereas B2 decreases with the strain rate, leading to a decrease or increase in the ubiquitiformal complexity. The ubiquitiformal complexity of slate and tuff ranges from 1.77 to 1.90 and 1.76 to 1.86, respectively. A more comprehensive assessment of the rock can be obtained by analyzing the relationship between the size effect, strain rate, and brittleness index of the rock after damage. [ABSTRACT FROM AUTHOR]

The risk transmission mechanisms of urban river ecological management engineering projects are examined in this study. Using the Susceptible Exposed Infectious Recovered Susceptible (SEIRS) model for risk transmission, a model of risk propagation delay for urban river ecological management engineering projects on scale-free networks is developed, which takes into account the effects of risk propagation and delay. We conducted a steady-state analysis of the model and obtained the basic reproduction number R. When R > 1, the equilibrium point of risk outbreak is stable, and when R < 1, the equilibrium point of risk disappearance is stable. Numerical simulations of the model were conducted using the MATLAB2022b to reveal the dynamic propagation patterns of risk in urban river ecological management engineering projects. The research results show that the steady-state density of the infected nodes in the network increases with the increase in the effective propagation rate and the propagation delay time; the propagation delay reduces the risk propagation threshold in the network and accelerates the occurrence of the equilibrium state of risk outbreak. There is a correlation between the transmission rate of latent nodes and the transmission rate of infected nodes, and the effective transmission rate of latent nodes has a greater influence on risk propagation. The spread of risk in the network can be effectively controlled and mitigated with targeted immunity for susceptible nodes. This article, based on the theory of complex networks and the mean-field theory, takes into account the propagation delay and spreading of latent nodes. Building a D-SEIRS model for risk propagation broadens the research perspective on urban river ecological management risk propagation. [ABSTRACT FROM AUTHOR]

The evolution and transfer of risk elements of urban river ecological management projects are primarily responsible for the difficulty of risk management in these projects. In this paper, we identify 63 risk elements of urban river ecological management projects using in-depth literature reviews and brainstorming. The association among all the risk elements is constructed using an expert survey method, and the risk elements are utilized as network nodes. The relationships between these nodes are then used as network edges (i.e., paths) to construct a complex network model. By using the network visualization and analysis tool anaconda3, we analyze the overall and local characteristic parameters of the risk network. The risk transmission characteristics of the urban river ecological management project are analyzed according to the parameter characteristics to reveal the inner relationships of risk transmission inherent in the complex network. We use the Jinghe ecological management project in Jinghe New City to verify the effectiveness of the proposed model. The study demonstrates that the starting node risk needs to be controlled, and the conduction node that indirectly triggers risk propagation needs to be cut off to achieve risk prevention and control. Accordingly, the risk prevention strategy is proposed, namely, paying close attention to the starting nodes of schedule delay risk, construction cycle risk and cost overrun risk, as well as the conduction risk nodes of project complexity risk, quality assessment risk, construction accident risk and improper drawing design risk. Effective measures should be taken to control the transmission and occurrence of risks based on these two aspects. The study reveals the network evolution of risk factors, which enriches the theory of the risk factor network evolution and evaluation of urban river ecological management projects. [ABSTRACT FROM AUTHOR]

Under the background of global climate change and rapid development of urbanization, urban extreme occurs more frequently. In consideration of the existing problems in the emergency management decision-making of urban rainstorm and flood disasters in China, this study put forward the decision-making method of urban rainstorm and flood disaster emergency management based on similar cases analysis method. Based on the evolution process of urban waterlogging disaster, the problem attribute system of urban rainstorm and flood disasters was established. The case-based reasoning (CBR) method was used to calculate the global similarity to determine the best historical case. The case-based decision theory (CBDT) method was used to calculate the comprehensive utility value of alternative cases to determine the optimal alternative cases. The empirical analysis was took in Xi'an city, one of the national center cities of China. Results show that the CBR method was used to obtain the highest similarity of historical case P3, which is 0.481. The CBDT method was used to calculate the high similarity of historical cases P3 and P4 to form the similar case set, with the similarity of 0.820 and 0.851, respectively. Combined with the event development, the comprehensive utility values were calculated. When the decision-maker pays the same attention to the emergency effect and response cost, the comprehensive utility value of P3 and P4 is 0.922 and 0.900, respectively, and P3 is the best reference scheme. By comparison, the latter is more suitable. The results can provide scientific basis for emergency management of urban rainstorm and flood disasters. [ABSTRACT FROM AUTHOR]

Collusion is unethical and anti-competitive behavior, which has become a prominent issue in the construction industry. However, existing studies were unable to identify the degree of collusion suspected for each bidder, which has little significance to regulators. Therefore, we develop a bidder network for the supervision project in Shaanxi Province, China, and analyze the behavioral characteristics of bidders from three levels. The results indicate that the bidding network is low-density, scale-free, and small-world at the macro level. The possibility of potential collusion is extremely high among supervisory enterprises. At the meso level, the bidder network can be divided into multiple communities and subgraphs with a high degree of cohesion, and the level of conspiracy suspicion was divided into four categories. At the micro level, the number of co-bidding among the bidders with the highest suspicion was extremely high, with higher winning bid times and significantly abnormal regularity of the bidding price, which is typical of bid-winning rotation practice. These results provide an effective method for Chinese government regulators, which are conducive to the formation of a good collusion regulatory system worldwide. [ABSTRACT FROM AUTHOR]

State‐of‐health (SOH) estimation is essential for evaluating the aging process of lithium‐ion batteries, which can effectively guarantee the steady application of the battery system. Most existing prediction approaches apply a single model or a single feature to achieve SOH estimation based on the entire charging curve. In this paper, a multifeature‐based stacked ensemble learning framework is proposed for SOH prediction using partial charging curves. Firstly, combined with the range of state‐of‐charge (SOC) commonly used in the actual operation of vehicles, the charging segment is effectively intercepted through the mapping correlation between the SOC and the terminal voltage. Then, five relevant features characterizing the battery health status are extracted from multiple data, such as temperature, voltage, and incremental capacity profiles. Finally, a two‐level stacking ensemble framework is developed to fuse several individual estimation methods for higher SOH accuracy. To validate the performance of the proposed method, the Oxford University data set and the NASA data set are deployed for comparison experiments, and the results reveal the superior precision and robustness of the developed model in SOH estimation. [ABSTRACT FROM AUTHOR]

The use of insect-resistant transgenic crops producing Bacillus thuringiensis protein Cry toxins (Bt) to control caterpillars is wide-spread. Development of a mechanism to prevent Bt from reaching its target site in the digestive system could result in Bt resistance and resistance to other insecticides active per os. Increased feeding rates by increasing temperature in tobacco budworms, Chloridea virescens, and bollworms, Helicoverpa zea, decreased Bt Cry1Ac susceptibility and mortality. The same was found in C. virescens for Bollgard II plant extract containing Bt Cry1Ac and Cry2Ab2 toxins. Furthermore, H. zea from the same inbred laboratory colony that fed faster independent of temperature manipulation were less susceptible to Bt intoxication. A laboratory derived C. virescens Bt resistant strain demonstrated a higher feeding rate on non-Bt artificial diet than the parental, Bt susceptible strain. A laboratory-reared Bt resistant fall armyworm, Spodoptera frugiperda, strain also fed faster on non-Bt diet compared to Bt susceptible caterpillars of the same species, both originally collected from corn. The studies in toto and the literature reviewed support the hypothesis that increased feeding rate is a behavioral mechanism for reducing caterpillar susceptibility to Bt. Its possible role in resistance needs further study. [ABSTRACT FROM AUTHOR]

A magnet-rotating-type axial magnetic coupler (MAMC), namely, a novel axial magnetic coupler with rotatable monopole permanent magnets (PMs), is proposed. The speed of the MAMC can be adjusted by rotating the rotatable PMs mounted on the PM disk, or changing the axial air gap length between the PM disk and the conductor sheet (CS), or combining these methods. In order to analyze the torque performance, the magnetic circuit model of MAMC is established when the rotatable PMs are not parallel to the CS. Specifically, the influence of the induced eddy current is introduced into a new magnetic equivalent circuit (MEC) model. Combined with Kirchhoff’s law, the calculation formula of torque is derived. Moreover, according to Ampere’s law, the formula for calculating the induced eddy current is derived when the rotatable PMs after rotating are not parallel to the CS. Finally, the effectiveness of the proposed model is verified by the finite element method (FEM). The results obtained by the new MEC model proposed are consistent with those obtained by the FEM, and the formula derived is effective in the case of small rotational speed differences, small air gap lengths, and small thicknesses of the CS. [ABSTRACT FROM AUTHOR]

The utilization of regional climate methods (RCMs) to predict future climate is an important study under the changing environment. The primary objective of the paper is to correct the temperature and precipitation simulations for the period of 1980–2005 and 2026–2098 in the Wei River Basin (WRB), to evaluate the performance of RCMs for the period of 1980–2005, and further, to analyze the future changes of projected temperature and precipitation during 2026–2098. In this paper, the linear scaling method was used to correct the temperature simulations. Quantile mapping, local intensity scaling method, and hybrid method were used to correct the precipitation simulations. The future changes of projected temperature and precipitation for the near term (2026–2050), mid-term (2051–2075), and far term (2076–2098), relative to the period of 1980–2005, were investigated under RCP 2.6 and RCP 8.5. Results indicate that (1) the temperature biases were either warm or cold in the spatial scale, and the precipitation wet biases were detected. After correction, HadGEM2-ES driven by RegCM4-4 had the best temperature reproducibility, and NCC-NorESM1-M driven by RegCM4-4 had the best precipitation reproducibility. (2) Under RCP 2.6, the projected annual, winter, and spring temperature showed decreasing trends. The temperature was higher than that for the period of 1980–2005 except for the spring temperature decreases in the Beiluo River Basin. Under RCP 8.5, the temperature showed significantly increasing trends. The temperature for the near term was similar to that of the period of 1980–2005, while the temperature increased significantly for the mid-term and far term. (3) Under RCP 2.6, the precipitation had decreasing trends. Under RCP 8.5, precipitation trends were also spatially distributed. The relative deviation of winter precipitation was the largest. Relative to the period of 1980–2005, the light- and moderate-rain days showed little change for the period of 2026–2098, while the extreme-rain days showed significantly increasing trends. [ABSTRACT FROM AUTHOR]

Damping is a significant dynamic characteristic used to describe rock vibration failures and plays an important role in various seismic engineering applications, specifically for evaluating stability of rock masses under forced vibration loading. In this paper, cyclic loading tests were carried out on sandstone and granite samples to study their damping characteristics. The effect of the selected influential indicators (stress level, strain amplitude and loading frequency) on the damping ratio and damping coefficient was studied. The damping parameters of sandstone and granite were calculated and the variability in the damping parameters as a function of stress level, frequency and strain amplitude were determined. The linear relationship between damping ratio, damping coefficient and strain amplitude was investigated. The results suggest that the relationship between the damping parameters and the strain amplitude could be expressed as a linear function. The influential indicators to the damping parameter of granite were sorted as follows: stress level > strain amplitude > frequency. The influential indicators of sandstone were sorted as follows: strain amplitude > stress level > frequency. Under a fixed-amplitude stress path, the damping ratio of granite was approximately 80% that of the sandstone and the damping coefficient is approximately 200% of that of the sandstone. [ABSTRACT FROM AUTHOR]

Contracted water-saving management (CWSM) has emerged as a powerful model for water-saving actions. In a CWSM project, whether the benefit allocation among the stakeholders is fair and reasonable will affect the enthusiasm of stakeholders for participating in the project, as well as the stability of the project's operations. This study identifies core stakeholders in CWSM projects of colleges/universities. Then, a preliminary benefit allocation model is constructed through the Shapley value method, risks are identified, and a modified model is developed based on the COWA-gray fixed weight clustering method. Finally, a CWSM project launched by a Chinese university is studied to verify the applicability of the modified model. [ABSTRACT FROM AUTHOR]

Payments for Water-Related Ecosystem Services (PWES) are increasingly popular for promoting water ecological conservation, and their impact on development is of considerable interest. This study estimates the economic impact of PWES on protected areas using the synthetic control method. Taking the Middle Route of the South to North Water Diversion Project in China as a case study, we find that the per capita GDP in protected areas increased markedly relative to synthetic control regions, and PWES had a positive economic impact. Additionally, we conducted many placebo tests to verify the validity and robustness of the results. We believe that the main factor responsible for the positive effect lies in developing the ecological-economic industrial system. This study provides a baseline for synthetic control analysis of PWES to compare regions of interest with their counterfactuals. The case study findings provide reference for the economic development of protected areas. [ABSTRACT FROM AUTHOR]

Highlights: The radius of the plastic zone and the radial stress is introduces into the stress-intensity ratio. A new rockburst criterion is proposed to predict the rockburst classification. The certain relationship between the rockburst rating and the radius of the plastic zone and radial stress is studied. [ABSTRACT FROM AUTHOR]

Rock strength parameters are substantially impacted by porosity. This paper proposes a new model for presenting the relationship between porosity and the ratio of the unconfined compressive strength to the tensile strength of rock. The correlation between porosity and the constant mi of the Hoek–Brown (H–B) criterion is studied. To consider the effect of porosity on the rock strength ratio, the H–B criterion is modified by incorporating porosity instead of the H–B constants mi and s. A series of uniaxial, triaxial and Brazilian tests are conducted on various types of rocks (sedimentary, metamorphic and magmatic rocks) to study the effect of porosity on rock strength characteristics. The modified H–B criterion provides a good representation of the effect of porosity on the failure envelopes of rock. The modified criterion can be used to estimate the porosity and strength parameters of rock. [ABSTRACT FROM AUTHOR]

The prefabricated construction industry has entered a new stage of development with the support of national policies. In order to solve the optimal scheduling problem of transportation vehicles in urban multi-prefabricated component factories, in this study, the aggregation optimization algorithm is introduced, and a new hybrid optimization algorithm is designed and improved, that is, the improved hybrid difference firefly algorithm (IHDFA). On the basis of fully considering the transportation cost and road traffic impedance, the prefabricated component factory constructs a linear programming model with the shortest transportation path and the lowest comprehensive cost as the main goal to reasonably plan the driving arrangement of transportation vehicles. Finally, the IHDFA algorithm is applied to a specific example and compared with the genetic algorithm, firefly algorithm, differential evolution algorithm, particle swarm algorithm, and hybrid differential firefly algorithm. The results show that the IHDFA proposed in this study effectively reduces the comprehensive transportation cost of prefabricated components, which verifies the practicability and effectiveness of the optimization model and algorithm. [ABSTRACT FROM AUTHOR]

In this paper, we attempt to answer the following questions: Which factors determine college students' water-saving behaviors? The answer can enable colleges to take targeted water management measures to promote water-saving behaviors of students. Based on the theory of planned behavior and the combination of attitude-situation-behavior theory, this paper built a comprehensive theoretical model with sociodemographic characteristics, psychological characteristics as external dependent latent variables, situational factors as moderating variables, and water-saving behaviors as internal dependent latent variables. The research investigated 742 students in China colleges, and used corresponding methods to analyze the different types of the influencing factors of students' water-saving behaviors. The results show that the sociodemographic characteristics of college students have no significant impact on water-saving behaviors; the psychological characteristics have a significant impact on individual water-saving behaviors; the situational factors have a significant moderating effect on individual water-saving behaviors of students. [ABSTRACT FROM AUTHOR]

Yan, D.; Jiang, R.; Xie, J.; Zhu, J.; Liang, J., and Wang, Y., 2021. A multivariate and multistage streamflow prediction model based on signal decomposition techniques with deep learning. Journal of Coastal Research, 37(6), 1260–1270. Coconut Creek (Florida), ISSN 0749-0208. Accurate streamflow forecast plays an important role in the flood control operation of reservoir and water resource management, and how to build a prediction model with high accuracy is a research hotspot. In order to improve the prediction accuracy, this paper establishes a multivariate and multistage streamflow prediction model based on the combination of mode decomposition and deep learning models, including the variational mode decomposition (VMD), improved complete ensemble empirical mode decomposition with adaptive noise (ICEEMD), convolutional neural network (CNN), and long short-term memory (LSTM). Taking the Wei River Basin (WRB) of China as an example, streamflow in six hydrometric stations from the main stream of the WRB is used to validate the model. The results show that the proposed model have good prediction skills, and the prediction results of multistage models are better than single-stage models; however, the most complex models do not have the best results. The VMD also preformed better prediction skills than ICEEMD, and the optimal model was VCL (VMD-CNN-LSTM). The root-mean-square error, peak percentage of threshold statistic, and Nash-Sutcliffe efficiency coefficient of VCL at Huaxian station are 43.82 m3/s, 10.02%, and 0.94, respectively. The models proposed in this paper are suitable for streamflow forecasting, which provide reference for streamflow forecasting and sustainable watershed management. [ABSTRACT FROM AUTHOR]

Bidder collusion seriously undermines the fair competition of the construction project market, and effective identification of collusion behaviors is of vital importance to the implementation of proactive regulation and supervision. In this paper, the data of construction project bidders from 2011 to 2018 are selected in Shaanxi Province, China, and a bidder network of construction projects is constructed. The collusion suspicion of bidders is analyzed from the macro-, meso-, and microlevels. The results show that the bidder network has features as small world at macrolevels, and it is easy for bidders to involve in collusion. The network community formed by construction, supervision, and survey and design bidding enterprises is analyzed at the mesolevel, and the collusion of supervision enterprises is found to have the highest suspicion At the microlevel, the characteristic value judgment and community division are adopted to analyze the collusion suspicion, which is divided into high, medium, and low according to the possibility. Through a comparison with the actual data, it is found that the method proposed in this paper can effectively identify the collusion behavior of construction project bidders. This paper proposes red, yellow, and green warning mechanism and formulates hierarchical accurate management preparedness, which can provide some suggestions to help prevent bidders from colluding. [ABSTRACT FROM AUTHOR]

Bidder collusion seriously undermines the fair competition of the construction project market, and effective identification of collusion behaviors is of vital importance to the implementation of proactive regulation and supervision. In this paper, the data of construction project bidders from 2011 to 2018 are selected in Shaanxi Province, China, and a bidder network of construction projects is constructed. The collusion suspicion of bidders is analyzed from the macro-, meso-, and microlevels. The results show that the bidder network has features as small world at macrolevels, and it is easy for bidders to involve in collusion. The network community formed by construction, supervision, and survey and design bidding enterprises is analyzed at the mesolevel, and the collusion of supervision enterprises is found to have the highest suspicion At the microlevel, the characteristic value judgment and community division are adopted to analyze the collusion suspicion, which is divided into high, medium, and low according to the possibility. Through a comparison with the actual data, it is found that the method proposed in this paper can effectively identify the collusion behavior of construction project bidders. This paper proposes red, yellow, and green warning mechanism and formulates hierarchical accurate management preparedness, which can provide some suggestions to help prevent bidders from colluding. [ABSTRACT FROM AUTHOR]

Chicken feather keratin (CK), a biomaterial that contains a large amount of nitrogen is extracted from chicken feathers and has significant potential for use as a flame retardant. In this study, CK and 9,10‐dihydro‐9‐oxa‐10‐phosphenanthrene‐10‐oxide (DOPO) were added in different amounts to an epoxy resin (EP), and their flame retardancy and smoke suppression effects were studied. The results showed that CK exhibits a good flame‐retardancy effect and better smoke suppression characteristics than those of DOPO when added to EP. Furthermore, it greatly reduces the CO yield in smoke. While the EP samples with DOPO showed better flame‐retardancy properties than those of the samples with CK, they also produced more smoke, which had a higher CO content. Furthermore, when CK and DOPO were added to EP together, the flame‐retardancy characteristics of the samples varied with the CK/DOPO ratio. Then the pyrolysis of all samples was divided into two stages based on thermokinetics analysis and the activation energies of these samples in the two stages were investigated. Finally, the flame‐retardancy mechanism was discussed. When samples burn, the PO· free radicals derived from DOPO combine with H· and OH· to induce a quenching effect. In addition, the phosphate resulting from the decomposition of DOPO promotes the formation of the char layer. At the same time, the noncombustible gases generated during the pyrolysis of CK cause the char layer to expand and remove some of the heat. Thus, CK and DOPO synergistically improved the flame retardancy of EP. [ABSTRACT FROM AUTHOR]

In the present paper, the amplitude-frequency characteristics of torsional vibration are discussed theoretically and experimentally for automotive powertrain. A bending-torsional-lateral-rocking coupled dynamic model with time-dependent mesh stiffness, backlash, transmission error etc. is proposed by the lumped-mass method to analysis the amplitude-frequency characteristic of torsional vibration for practical purposes, and equations of motive are derived. The Runge–Kutta method is employed to conduct a sweep frequency response analysis numerically. Furthermore, a torsional experiment is performed and validates the feasibility of the theoretical model. As a result, some torsional characteristics of automotive powertrain are obtained. The first three-order nature torsional frequencies are predicted. Torsional behaviors only affect the vibration characteristics of a complete vehicle at low-speed condition and will be reinforced expectedly while increasing torque fluctuation. Gear mesh excitations have little effects on torsional responses for such components located before mesh point but a lot for ones behind it. In particular, it is noted that the torsional system has a stiffness-softening characteristic with respect to torque fluctuation. [ABSTRACT FROM AUTHOR]

This study is aimed at investigating the effects of intermediate support stiffness on nonlinear vibration response of transmission system. A coupled bending–torsional–lateral dynamic model with 14 degrees of freedom of transmission system is proposed comprehensively considering rubber dynamic stiffness, time-varying stiffness, static transmission error, and backlash. Meanwhile, a model of intermediate support with rubber nonlinear properties is developed to improve the accuracy of analysis. On the basis of the nonlinear differential equations derived by the lumped-parameter method, the dynamic responses of the key parts in the transmission system are obtained using the Runge–Kutta method and the effects of intermediate support stiffness on the dynamic characteristics are analyzed. Numerical results show that complicated interaction occurs and intermediate support stiffness has a great influence on the vibration of the coupled system. With the increase in the intermediate support stiffness, the vibration displacements in the three directions of the gear are progressively reduced and the nature frequencies are changed. The influence of the radial stiffness is greater than that of the axial stiffness. An experiment is performed subsequently to validate the effect of intermediate support stiffness on system, and the experimental results are consistent with numerical ones. [ABSTRACT FROM AUTHOR]

Wang, X.; Jiang, R.; Xie, J.; Zhao, Y.; Li, F., and Zhu, J., 2019. Multiscale variability of precipitation and their teleconnection with large-scale climate anomalies: A case study of Xi'an city, China. In: Guido-Aldana, P.A. and Mulahasan, S. (eds.), Advances in Water Resources and Exploration. Journal of Coastal Research, Special Issue No. 93, pp. 417–426. Coconut Creek (Florida), ISSN 0749-0208. The changes of precipitation affect the urban rainstorm waterlogging and water resources management, which have important influences on the sustainable development of society. The primary objective of the paper is to provide theoretical basis for local water resources management and disaster prevention and reduction by analyzing the multiscale variability of precipitation and their teleconnection with large-scale climate anomalies in Xi'an city of China. The change characteristics of precipitation and extreme precipitation indices were investigated using Mann-Kendall test, Spearman's rank correlation and wavelet analysis. The cross wavelet transform and wavelet coherence were used to explore the correlations between the precipitation and large-scale teleconnection indices such as Arctic Oscillation (AO), Southern Oscillation Index (SOI), El Niño-Southern Oscillation (ENSO) and sunspot. Results indicate that: the precipitation was mainly concentrated in summer, followed by autumn. The annual, seasonal and monthly precipitation except June and August had decreasing trends, and the magnitudes of precipitation decrease were more pronounced in spring, April and November. The change patterns varied for extreme precipitation indices. The temporal variation in extreme precipitation indices indicated that the extreme precipitation events had mainly increased during 1971-1990 and 1991-2017, and decreased during 1951-1970 and 1951-2017, especially, increased more pronounced during 1991-2017 and decreased more pronounced during 1951-1970. The precipitation exhibited a fluctuant change from increase to decrease, then increase to decrease and finally increase trends, and there was an abrupt change point in 1965. The annual precipitation had statistically significant cycles of 3-5 year and 7-10 year at 5% significance level. The large-scale teleconnection indices affected the precipitation in Xi'an city. The phase differences between precipitation and teleconnection indices including AO and SOI were in-phase dominated, and anti-phase dominated between precipitation and teleconnection indices including ENSO and sunspot, indicating that the AO and SOI exerted positive climate impacts on the precipitation and vice-versa for ENSO and sunspot. [ABSTRACT FROM AUTHOR]

Li, W.; Jiang, R.; Zhao, Y.; Xie, J.; Zhu, J., and Cao, R., 2019. Water ecological environment protection under changing environment: A systematic review and bibliometric analysis. In: Guido-Aldana, P.A. and Mulahasan, S. (eds.), Advances in Water Resources and Exploration. Journal of Coastal Research, Special Issue No. 93, pp. 9–15. Coconut Creek (Florida), ISSN 0749-0208. Systematic review is usually used to reveal the change characteristics of the quantity and law of the citations focus on one research theme. The paper investigated the research status, development trend and hotspots of water ecological environment protection using bibliometric analysis. Based on bibliometric, mathematics and statistics, articles related to the water ecological environment protection in Web of Science for the period of 2008-2019 were selected. CiteSpace software was used to conduct the annual frequency analysis of papers, countries and research institutions analysis, co-occurring keywords analysis, clustering analysis and research frontier. Results show that: (1) The number of published papers and cited papers have increased for the past 12 years. Especially, the number of published papers has increased sharply since 2015, indicating that the research on water ecological environment protection has been transferred from the exploration stage to rapid development stage, which needs to be analyzed from the aspects of national policy. (2) China has more publications than other countries. The research institutions are mainly concentrated on universities, the cooperation among them is not close. It shows the characteristics of small distribution and large concentration. Keywords such as "model" and "water quality" are research hotspots. (3) The results of clustering analysis show that water ecological environment quality assessment, water and soil conservation, ecosystem services and aquatic ecosystem are four main research directions of water ecological environment protection. (4) Using method of burst detection, nine keywords are obtained, which indicate that water ecological environment protection has rich research perspectives. The burst strength of land use is high, it will become the research hotspot of water ecological environment protection in future. The results should be beneficial to systematically understand research progress and future trends of water ecologic environment under changing environment, and therefore it promotes ecological civilization construction. [ABSTRACT FROM AUTHOR]

Ship target recognition has always been a hot issue in the field of ocean surveillance. Due to the serious shortage of samples in ship target recognition for synthetic aperture radar (SAR) images, the template-based method is still one of the most effective ways to solve the problem. In this letter, we put forward a novel ship recognition method based on the projection shape template (PST), aiming at increasing both the accuracy and the robustness of the recognition. The PST of each category is calculated by projecting the 3-D model obtained from the two-view images of the target to the 2-D slant-plane image according to the SAR imaging model. Then, we propose a contour extraction method to detect the profile of ships, which served as the feature. Finally, the identity of the query ship is obtained through contour matching. Experimental results indicate that the proposed method is effective even when the number of samples is extremely small, consequently providing a promising way for the automatic interpretation of ship targets in the SAR images. [ABSTRACT FROM PUBLISHER]

As one of the most popular vegetation indices to monitor terrestrial vegetation productivity, Normalized Difference Vegetation Index (NDVI) has been widely used to study the plant growth and vegetation productivity around the world, especially the dynamic response of vegetation to climate change in terms of precipitation and temperature. Alberta is the most important agricultural and forestry province and with the best climatic observation systems in Canada. However, few studies pertaining to climate change and vegetation productivity are found. The objectives of this paper therefore were to better understand impacts of climate change on vegetation productivity in Alberta using the NDVI and provide reference for policy makers and stakeholders. We investigated the following: (1) the variations of Alberta's smoothed NDVI (sNDVI, eliminated noise compared to NDVI) and two climatic variables (precipitation and temperature) using non-parametric Mann-Kendall monotonic test and Thiel-Sen's slope; (2) the relationships between sNDVI and climatic variables, and the potential predictability of sNDVI using climatic variables as predictors based on two predicted models; and (3) the use of a linear regression model and an artificial neural network calibrated by the genetic algorithm (ANN-GA) to estimate Alberta's sNDVI using precipitation and temperature as predictors. The results showed that (1) the monthly sNDVI has increased during the past 30 years and a lengthened growing season was detected; (2) vegetation productivity in northern Alberta was mainly temperature driven and the vegetation in southern Alberta was predominantly precipitation driven for the period of 1982-2011; and (3) better performances of the sNDVI-climate relationships were obtained by nonlinear model (ANN-GA) than using linear (regression) model. Similar results detected in both monthly and summer sNDVI prediction using climatic variables as predictors revealed the applicability of two models for different period of year ecologists might focus on. [ABSTRACT FROM AUTHOR]

Juvenile hormone (JH) controls the growth, development, metamorphosis, and reproduction of insects. For many years, the general assumption has been that JH regulates tick and other acarine development and reproduction the same as in insects. Although researchers have not been able to find the common insect JHs in hard and soft tick species and JH applications appear to have no effect on tick development, it is difficult to prove the negative or to determine whether precursors to JH are made in ticks. The tick synganglion contains regions which are homologous to the corpora allata, the biosynthetic source for JH in insects. Next-gen sequencing of the tick synganglion transcriptome was conducted separately in adults of the American dog tick, Dermacentor variabilis, the deer tick, Ixodes scapularis, and the relapsing fever tick, Ornithodoros turicata as a new approach to determine whether ticks can make JH or a JH precursor. All of the enzymes that make up the mevalonate pathway from acetyl-CoA to farnesyl diphosphate (acetoacetyl-CoA thiolase, HMG-S, HMG-R, mevalonate kinase, phosphomevalonate kinase, diphosphomevalonate decarboxylase, and farnesyl diphosphate synthase) were found in at least one of the ticks studied but most were found in all three species. Sequence analysis of the last enzyme in the mevalonate pathway, farnesyl diphosphate synthase, demonstrated conservation of the seven prenyltransferase regions and the aspartate rich motifs within those regions typical of this enzyme. In the JH branch from farnesyl diphosphate to JH III, we found a putative farnesol oxidase used for the conversion of farnesol to farnesal in the synganglion transcriptome of I. scapularis and D. variabilis. Methyltransferases (MTs) that add a methyl group to farnesoic acid to make methyl farnesoate were present in all of the ticks studied with similarities as high as 36% at the amino acid level to insect JH acid methyltransferase (JHAMT). However, when the tick MTs were compared to the known insect JHAMTs from several insect species at the amino acid level, the former lacked the farnesoic acid binding motif typical in insects. The P450s shown in insects to add the C10,11 epoxide to methyl farnesoate, are in the CYP15 family; this family was absent in our tick transcriptomes and in the I. scapularis genome, the only tick genome available. These data suggest that ticks do not synthesize JH III but have the mevalonate pathway and may produce a JH III precursor. [ABSTRACT FROM AUTHOR]

Wang, X.; Jiang, R.; Xie, J.; Zhao, Y.; Li, F., and Zhu, J., 2019. Multiscale variability of precipitation and their teleconnection with large-scale climate anomalies: A case study of Xi'an city, China. In: Guido-Aldana, P.A. and Mulahasan, S. (eds.), Advances in Water Resources and Exploration. Journal of Coastal Research, Special Issue No. 93, pp. 417–426. Coconut Creek (Florida), ISSN 0749-0208. The changes of precipitation affect the urban rainstorm waterlogging and water resources management, which have important influences on the sustainable development of society. The primary objective of the paper is to provide theoretical basis for local water resources management and disaster prevention and reduction by analyzing the multiscale variability of precipitation and their teleconnection with large-scale climate anomalies in Xi'an city of China. The change characteristics of precipitation and extreme precipitation indices were investigated using Mann-Kendall test, Spearman's rank correlation and wavelet analysis. The cross wavelet transform and wavelet coherence were used to explore the correlations between the precipitation and large-scale teleconnection indices such as Arctic Oscillation (AO), Southern Oscillation Index (SOI), El Niño-Southern Oscillation (ENSO) and sunspot. Results indicate that: the precipitation was mainly concentrated in summer, followed by autumn. The annual, seasonal and monthly precipitation except June and August had decreasing trends, and the magnitudes of precipitation decrease were more pronounced in spring, April and November. The change patterns varied for extreme precipitation indices. The temporal variation in extreme precipitation indices indicated that the extreme precipitation events had mainly increased during 1971-1990 and 1991-2017, and decreased during 1951-1970 and 1951-2017, especially, increased more pronounced during 1991-2017 and decreased more pronounced during 1951-1970. The precipitation exhibited a fluctuant change from increase to decrease, then increase to decrease and finally increase trends, and there was an abrupt change point in 1965. The annual precipitation had statistically significant cycles of 3-5 year and 7-10 year at 5% significance level. The large-scale teleconnection indices affected the precipitation in Xi'an city. The phase differences between precipitation and teleconnection indices including AO and SOI were in-phase dominated, and anti-phase dominated between precipitation and teleconnection indices including ENSO and sunspot, indicating that the AO and SOI exerted positive climate impacts on the precipitation and vice-versa for ENSO and sunspot. [ABSTRACT FROM AUTHOR]

Li, W.; Jiang, R.; Zhao, Y.; Xie, J.; Zhu, J., and Cao, R., 2019. Water ecological environment protection under changing environment: A systematic review and bibliometric analysis. In: Guido-Aldana, P.A. and Mulahasan, S. (eds.), Advances in Water Resources and Exploration. Journal of Coastal Research, Special Issue No. 93, pp. 9–15. Coconut Creek (Florida), ISSN 0749-0208. Systematic review is usually used to reveal the change characteristics of the quantity and law of the citations focus on one research theme. The paper investigated the research status, development trend and hotspots of water ecological environment protection using bibliometric analysis. Based on bibliometric, mathematics and statistics, articles related to the water ecological environment protection in Web of Science for the period of 2008-2019 were selected. CiteSpace software was used to conduct the annual frequency analysis of papers, countries and research institutions analysis, co-occurring keywords analysis, clustering analysis and research frontier. Results show that: (1) The number of published papers and cited papers have increased for the past 12 years. Especially, the number of published papers has increased sharply since 2015, indicating that the research on water ecological environment protection has been transferred from the exploration stage to rapid development stage, which needs to be analyzed from the aspects of national policy. (2) China has more publications than other countries. The research institutions are mainly concentrated on universities, the cooperation among them is not close. It shows the characteristics of small distribution and large concentration. Keywords such as "model" and "water quality" are research hotspots. (3) The results of clustering analysis show that water ecological environment quality assessment, water and soil conservation, ecosystem services and aquatic ecosystem are four main research directions of water ecological environment protection. (4) Using method of burst detection, nine keywords are obtained, which indicate that water ecological environment protection has rich research perspectives. The burst strength of land use is high, it will become the research hotspot of water ecological environment protection in future. The results should be beneficial to systematically understand research progress and future trends of water ecologic environment under changing environment, and therefore it promotes ecological civilization construction. [ABSTRACT FROM AUTHOR]

Drought severity was simulated with four drought indices to examine the impacts of climate change on drought conditions in Shaanxi province over the period 1951 to 2012. The drought metrics analyzed were based on the original Palmer drought severity index (orPDSI), self-calibrated PDSI (scPDSI), the standardized precipitation index (SPI) and the standardized precipitation evapotranspiration index (SPEI). Both Thornthwaite (Thor) and Penman-Monteith (PM) parameterizations were used to calculate potential evapotranspiration (PET), and the differences between two PET estimators were studied. Nonparametric Mann-Kendall monotonic test was used to examine the trends of hydroclimatic data. Series of drought indices were compared at five meteorological stations with different climate characteristics, located in the north, central and south parts of Shaanxi province, respectively. Effects of climate change in drought conditions were investigated with hypothetical progressive precipitation decrease (−15 %) and temperature increase (2 °C). The results showed that there was discrepancy between PET estimated using the Thor and PM parameterization estimators, while the SPEI calculated with the two PET estimators are found to be similar. The SPEI has the combined advantages over the scPDSI and the SPI, considering the effect of temperature variability on drought severity and its multi-scalar characteristic, while scPDSI has an inherent approximately 12-month time scale. The Pearson's correlation is used to compare the three pairs of drought indices combinations at different time scales. Under climate change conditions, the drought severity increases with the decline of precipitation and higher water demand as a result of the temperature increase based on the metrics of the scPDSI, the SPI and the SPEI. [ABSTRACT FROM AUTHOR]

Line curvature error greatly influences the quality of the diffraction wave fronts of machine-ruling gratings. To reduce the line curvature error, we propose a correction method that uses interferometric control. This method uses diffraction wave fronts of symmetrical orders to compute the mean line curvature error of the ruled grating, taking the mean line curvature error as the system line curvature error. To minimize the line curvature error of the grating, a dual-frequency laser interferometer is used as a real-time position feedback for the grating ruling stage, along with using a piezoelectric actuator to adjust the stage positioning to compensate the line curvature error. Our experiments show that the proposed method effectively reduced the peak-to-valley value of the line curvature error, improving the quality of the grating diffraction wave front. [ABSTRACT FROM AUTHOR]

With the continuous improvement of Synthetic Aperture Radar (SAR) resolution, interpreting the small targets like aircraft in SAR images becomes possible and turn out to be a hot spot in SAR application research. However, due to the complexity of SAR imaging mechanism, interpreting targets in SAR images is a tough problem. This paper presents a new aircraft interpretation method based on the joint time-frequency analysis and multi-dimensional contrasting of basic structures. Moreover, SAR data acquisition experiment is designed for interpreting the aircraft. Analyzing the experiment data with our method, the result shows that the proposed method largely makes use of the SAR data information. The reasonable results can provide some auxiliary support for the SAR images manual interpretation. [ABSTRACT FROM AUTHOR]

A new security test for the substitution boxes (S-boxes), high-order bit independence criterion (HOBIC) test, is presented. Different from the previous security tests for S-boxes, the HOBIC test can be used to measure the strength of an S-box against attacks that keep some of its input bits constant. Test results over the S-boxes of Data Encryption Standard (DES) and Advanced Encryption Standard (AES) are given and some possible applications of the HOBIC test are analyzed. Meanwhile, the source code for a basic version of the HOBIC test is also provided, the implement process of which shows that it is very fast and efficient for practical applications. [ABSTRACT FROM AUTHOR]

To achieve the sustainable development goals established by the United Nations in 2015, China has adopted a series of measures to promote the modernization of water conservancy. However, its construction in China is imbalanced across regions as the endowment of water resources and economic development are distinct. Consequently, it is important to assess the progress of and analyze the spatial heterogeneity of water conservancy modernization construction in China from the perspective of sustainable development goals (SDGs). In this study, 31 regions in China were selected, and data on water conservancy construction in these sampled regions (excluding Hong Kong, Macao, and Taiwan) were collected in 2018. The results show that there exists an imbalanced development in terms of the overall level and the index level. About 60% of the regions scored below the overall average score for China's current modernization of water conservancy. The eastern areas presented a high level of modernization, while the central, northeast, and western areas showed comparable modernization of water conservancy, all of which lag behind eastern areas of China. Furthermore, China's water conservancy modernization also presented a strong spatial autocorrelation, and there was at least one deficiency in 55% of the regions, with the rate of deficiencies emerging in the West being much higher than in other regions. In a nutshell, this study provides a novel framework that can be extended to evaluate the SDGs and the effectiveness of water governance in other countries. [ABSTRACT FROM AUTHOR]