Are Farmers Willing to Pay for Centralized Mode Provision of Rural Domestic Sewage Treatment? A Large-Scale Assessment in North China

peer reviewedEvaluation of farmers’ willingness to participate (WTPP) and willingness to pay (WTP) for the centralized mode provision (CMP) of rural domestic sewage treatment (RDST) is imperative to improve the rural environment as well as to alleviate government financial pressures. This study adopted the contingent valuation method as well as face-to-face interview questionnaires to assess rural residents’ provision mode preferences, WTPP, and WTP for the CMP of RDST in China. Based on 761 samples collected from Shandong, Jilin, and Gansu provinces of China, we applied econometric models to estimate farmers’ WTPP and WTP for the CMP of RDST and explore the potential influencing factors, respectively. Results show that 1) 81.87% of the farmers would be willing to contribute to CMP of RDST; 2) farmers’ perceptions of the necessity of RDST, pollution of rural domestic sewage, and government propaganda significantly and positively affect their WTP; and 3) the expected WTP for CMP of RDST with the total respondents and the respondents with positive WTPP were estimated to be 7.59 USD/year and 10.10 USD/year (for a total of 20 years), accounting for 16.28 and 21.65% of construction costs, respectively. Based on these outcomes, it could be further estimated that the aggregate value was between 179.05 million USD/year and 238.26 million USD/year which implied that the farmers’ WTP may be a potentially non-negligible funding source for the CMP of RDST. The enhancement of environmental awareness of farmers and strengthening of propaganda should be the next priority of the Chinese government. Priority should also be assigned to villages closer to towns when the government formulates relevant strategies and policies. The results of this study provide references for policy formulation related to broadening the funding sources in RDST and exploring farmer payment mechanisms and implications for other developing countries

Software-Defined GPU-CPU Empowered Efficient Wireless Federated Learning With Embedding Communication Coding for Beyond 5G

Currently, with the widespread of the intelligent Internet of Things (IoT) in beyond 5G, wireless federated learning (WFL) has attracted a lot of attention to enable knowledge construction and sharing among a huge amount of distributed edge devices. However, under unstable wireless channel conditions, existing WFL schemes exist the following challenges: First, learning model parameters will be disturbed by bit errors because of interference and noise during wireless transmission, which will affect the training accuracy and the loss of the learning model. Second, traditional edge devices with CPU acceleration are inefficient due to the low throughout computation, especially in accelerating the encoding and decoding process during wireless transmission. Third, current hardware-level GPU acceleration methods cannot optimize complex operations, for instance, complex wireless coding in the WFL environment. To address the above challenges, we propose a software-defined GPU-CPU empowered efficient WFL architecture with embedding LDPC communication coding. Specifically, we embed wireless channel coding into the server weight aggregation and the client local training process respectively to resist interruptions in the learning process and design a GPU-CPU acceleration scheme for this architecture. The experimental results show its anti-interference ability and GPU-CPU acceleration ability during wireless transmission, which is 10 times the error control capability and 100 times faster than existing WFL schemes

Diploid mycelia of Ustilago esculenta fails to maintain sustainable proliferation in host plant

Smut fungi display a uniform life cycle including two phases: a saprophytic phase in vitro and a parasitic phase in host plants. Several apathogenic smut fungi are found, lacking suitable hosts in their habitat. Interestingly, MT-type Ustilago esculenta was found to maintain a parasitic life, lacking the saprophytic phase. Its long period of asexual proliferation in plant tissue results in severe defects in certain functions. In this study, the growth dynamics of U. esculenta in plant tissues were carefully observed. The mycelia of T- and MT-type U. esculenta exhibit rapid growth after karyogamy and aggregate between cells. While T-type U. esculenta successfully forms teliospores after aggregation, the aggregated mycelia of MT-type U. esculenta gradually disappeared after a short period of massive proliferation. It may be resulted by the lack of nutrition such as glucose and sucrose. After overwintering, infected Zizania latifolia plants no longer contained diploid mycelia resulting from karyogamy. This indicated that diploid mycelia failed to survive in plant tissues. It seems that diploid mycelium only serves to generate teliospores. Notably, MT-type U. esculenta keeps the normal function of karyogamy, though it is not necessary for its asexual life in plant tissue. Further investigations are required to uncover the underlying mechanism, which would improve our understanding of the life cycle of smut fungi and help the breeding of Z. latifolia

Dynamic Response and Failure Characteristics of Slope with Weak Interlayer under Action of Near-Fault Ground Motion

Investigations into the Wenchuan earthquake (2008, China) demonstrated that landslides were concentrated in the near-fault areas, and numerous large-scale landslides occurred in slopes with weak interlayers. A mathematical model was established based on the shear beam theory, while a numerical model was developed based on the discrete element method which perfectly matched layer boundary theory. Through a theoretical analysis and numerical simulation, the dynamic response and failure modes of the slope with a weak interlayer under the near-fault ground motion were studied. It was found that a combined effect took place between the near-fault ground motion and the weak interlayer, causing the slope near a fault to be destroyed more easily. The coupling between the near-fault ground motion and the weak interlayer leads to a maximum amplification effect of the slope. The existence of a weak interlayer induces nonconforming vibration between the upper and the lower rock masses of the interlayer. The variation in the amplification effect along the slope elevation is related to the ratio of the input seismic period to the natural slope period. Under horizontal ground motion, weak interlayers will be subjected to impacting and shearing action. The failure mode of the slope with a weak interlayer under near-fault ground motion can be expressed as a trailing edge tension crack, as well as weak interlayer impacting and shearing failure

Stability Enhancement Method of Standalone Modular Multilevel Converters Based on Impedance Reshaping

Modular multilevel converters (MMCs) are susceptible to subsynchronous oscillations (SSOs) caused by impedance interactions in the power line. Current research into the stability of MMCs focuses mainly on voltage feed-forward control, while the effect of current feed-forward control is neglected. This paper proposes a current feed-forward compensation method based on impedance reshaping for standalone MMCs. Initially, an impedance model was developed to identify the stability risks caused by the interaction between the MMC and power line impedance. The proposed method feeds the current compensation signal into the modulation circuit, thereby improving the control signal and suppressing the impedance interaction between the MMC and the power line. The analysis of the harmonic state space (HSS) method verifies that the proposed approach effectively reduces the negative damping region in the frequency band where the SSO is located. Additionally, the impedance frequency scanning method confirms the accuracy of impedance modeling. Using the MATLAB/Simulink platform and StarSim HIL hardware-in-the-loop experimental platform, the SSO phenomenon of the MMC is simulated, and the results show that the proposed method can effectively suppress harmonic currents during SSO, which verifies the accuracy of the stability analysis and the feasibility of the proposed method

Long-Term Dynamics of Chlorophyll-a Concentration and Its Response to Human and Natural Factors in Lake Taihu Based on MODIS Data

Chlorophyll-a plays an essential biochemical role in the eutrophication process, and is widely considered an important water quality indicator for assessing human activity’s effects on aquatic ecosystems. Herein, 20 years of moderate resolution imaging spectroradiometer (MODIS) data were applied to investigate the spatiotemporal patterns and trends of chlorophyll-a concentration (Chla) in the eutrophic Lake Taihu, based on a new empirical model. The validated results suggested that our developed model presented appreciable performance in estimating Chla, with a root mean square error (MAPE) of 12.95 μg/L and mean absolute percentage error (RMSE) of 29.98%. Long-term MODIS observations suggested that the Chla of Lake Taihu experienced an overall increasing trend and significant spatiotemporal heterogeneity during 2002–2021. A driving factor analysis indicated that precipitation and air temperature had a significant impact on the monthly dynamics of Chla, while chemical fertilizer consumption, municipal wastewater, industrial sewage, precipitation, and air temperature were important driving factors and together explained more than 81% of the long-term dynamics of Chla. This study provides a 20 year recorded dataset of Chla for inland waters, offering new insights for future precise eutrophication control and efficient water resource management

How Environmental Regulation Affects Rural Residents’ Willingness to Pay for Sustainable Domestic Sewage Treatment: Mediating and Interaction Effects

Exploring the construction of effective payment mechanisms for rural residents could break the dilemma of the value of a single investment by the government in environmental governance and promote the process of sustainable rural domestic sewage treatment (RDST). The effects of environmental regulations have been roughly approved; however, their influence mechanisms on rural residents’ willingness to pay (WTP) and payment level for sustainable RDST have not been fully revealed. Based on a database of 744 respondents, an integrated model was developed to verify the heterogeneous effects of three environmental regulations on rural residents’ WTP and further explore their interaction effects and impact mechanisms. In addition, there is an urgent necessity to explore the effectiveness of implementing different combinations of environmental regulations. Our results indicated that, firstly, the guiding regulation and incentive regulation promoted rural residents’ WTP and payment level, whereas the binding regulation had a limited impact on individuals. Secondly, rural residents’ cognition mediated the effect of the environmental regulations on their WTP and payment level. Lastly, the guiding and incentive regulations showed a substitution relationship, while both guiding and binding regulations as well as incentive and binding regulations revealed a complementary relationship. The implications of these results indicate the importance of strengthening the public attention on the environmental and health hazards of rural domestic sewage and effectively raising rural residents’ environmental cognition and environmental protection awareness, thereby increasing their WTP and payment level for sustainable RDST. This study provides credible references and recommendations for environmental regulations’ formulation and policy optimization for RDST, as well as for the construction of payment systems for rural residents, and inspiration for rural environment management in other developing countries