Aims A field experiment was conducted to investigate the effect of biochar on maize yield and greenhouse gases (GHGs) in a calcareous loamy soil poor in organic carbon from Henan, central great ...plain, China. Methods Biochar was applied at rates of 0, 20 and 40 tha−1 with or without N fertilization. With N fertilization, urea was applied at 300 kg N ha−1, of which 60% was applied as basal fertilizer and 40% as supplementary fertilizer during crop growth. Soil emissions of CO2, CH4 and N2O were monitored using closed chambers at 7 days intervals throughout the whole maize growing season (WMGS). Results Biochar amendments significantly increased maize production but decreased GHGs. Maize yield was increased by 15.8% and 7.3% without N fertilization, and by 8.8% and 12.1% with N fertilization under biochar amendment at 20 tha−1 and 40 tha−1, respectively. Total N2O emission was decreased by 10.7% and by 41.8% under biochar amendment at 20 tha−1 and 40 tha−1 compared to no biochar amendment with N fertilization. The high rate of biochar (40 tha−1) increased the total CO2 emission by 12% without N fertilization. Overall, biochar amendments of 20 tha−1 and 40 tha−1 decreased the total global warming potential (GWP) of CH4 and N2O by 9.8% and by 41.5% without N fertilization, and by 23.8% and 47.6% with N fertilization, respectively. Biochar amendments also decreased soil bulk density and increased soil total N contents but had no effect on soil mineral N. Conclusions These results suggest that application of biochar to calcareous and infertile dry croplands poor in soil organic carbon will enhance crop productivity and reduce GHGs emissions.
One of the limitations of TiO2 based perovskite solar cells is the poor electron mobility of TiO2. Here, perovskite oxide BaSnO3 is used as a replacement. It has a higher electron mobility and the ...same perovskite structure as the light harvesting materials. After optimization, devices based on BaSnO3 showed the best performance of 12.3% vs. 11.1% for TiO2.
•A non-linear piecewise state function is designed to describe maintenance states.•A high-level maintenance planning model for high-speed trains is formulated.•The original model is linearized using ...a big M method.•Develop a simulated annealing algorithm to solve the relaxation model.•Conduct a real-world case study with 124 trains from the China Shanghai Railroad.
For safety reasons, a high-speed train needs to carry out the preventive maintenance when its accumulated running mileage or time reaches a predefined threshold. This paper formulates the train high-level preventive maintenance planning problem as a 0-1 programming model. A novel state function is designed to describe whether a train is under maintenance or not. By using this function, the constraint for restricting the total number of trains under maintenance can be formulated reasonably well. A linearization technique is also employed to refine the original non-linear state function into a linear one. To handle large-scale instances, a simulated annealing algorithm is proposed for solving the problem and is applied to a real-world case study from Shanghai Railway Bureau (SRB), a regional railway operator under China Railway. The optimized results yield a total cost of 3,619,200 standard train-km in terms of remaining mileage. In addition, sensitivity analyses based on the real-world case study reveal some interesting insights. We have delivered the results to SRB as a useful and efficient decision support tool for their high-level maintenance planning work.
This paper aims to investigate the economic risk contagion among major economies in the world by utilizing an innovative spillover analysis method accompanied with data from economic policy ...uncertainty (EPU) indices. To obtain more robust conclusions, the risk spillover effects are detected in both time and frequency domains. The empirical results show that, first of all, in terms of time-domain framework, the top six largest economies has strong connectedness in economic risk (uncertainty) and US seems to be both the major risk spillover contributor and receiver among these major economies. While regarding to frequency-domain analysis, most risk spillover effects are observed only in short-term frequency at 1 to 3 months. Secondly, the static net EPU spillover effects indicates that US, in average, is the key spillover transmitter and UK as well as China are the major spillover receivers. Finally, the dynamic rolling-window results confirm that with time-varying domestic and global economic situations, no country is identified as a successive net EPU spillover contributor or receiver across both time and various frequency domains. China, however, is presenting its upward economic strength and outside impacts in global economy system since about 2017.
•Economic risk contagion is analyzed in both time and frequency domains.•EPU indices of six major economies are employed as proxies of economic risk.•Both static and time-varying spillover effects are calculated.•US are the major risk spillover contributor and receiver.•Economic risk spillovers are mainly observed in short-term frequency.
Review on single-phase driven ultrasonic motors DongMei, Xu; BingJie, Zhang; SiMiao, Yu ...
Journal of Intelligent Material Systems and Structures,
03/2023, Letnik:
34, Številka:
5
Book Review, Journal Article
Recenzirano
In recent decades, various single-phase drive ultrasonic motors have emerged, and only a single excitation signal is used in their working states. Single-phase driven ultrasonic motors have the ...benefits of most ultrasonic motors, as well as the advantages of a simple driving circuit construction, low cost, high design flexibility, and high reliability, among others. According to the working principles, they are divided into three types: the vibration mode alternating type, the vibration mode coupling type, the vibration mode converting type. This paper summarizes various types of single-phase ultrasonic motors. The three types of the working principles and its representative structures are explained; output performances of the single-phase ultrasonic motors are described; then, practical and potential applications of the single-phase ultrasonic motors are introduced; finally, the research of single-phase ultrasonic motors are reviewed, and its development prospect is prospected. This review is helpful for a comprehensive understanding of single-phase drive ultrasonic motors. This paper offers the groundwork for the development of a novel single-phase driven ultrasonic motor with improved mechanical output.
To further investigate the effect of pyrolysis temperature on bioavailable Cd, Pb and As, as well as the bacterial community structure in multi-metal(loid) contaminated paddy soil, six types of ...biochar derived from wood sawdust and peanut shell at 300 °C, 500 °C and 700 °C were prepared and incubated with Cd, Pb and As contaminated paddy soil for 45 days. The results showed that adding biochar decreased bioavailable Cd by 31.3%− 42.9%, Pb by 0.61–56.1%, while bioavailable As changed from 9.68 mg kg−1 to 9.55–10.84 mg kg−1. We found that pyrolysis temperature of biochar had no significant effect on Cd bioavailability while Pb bioavailability decreased obviously with pyrolysis temperature raising. Biochar reduced the proportion of soluble and exchangeable Cd from 45.0% to 11.2–15.4% in comparison with the control, while no significant effect on the speciation of Pb and As. Wood sawdust biochar (WSBs) had more potential in decreasing bioavailable Cd and Pb than peanut shell biochar (PSBs). Although high-temperature biochar resulted a larger increase in bacterial species than low-and mid- temperature biochar, feedstock played a more important role in altering soil bacterial diversity and community composition than pyrolysis temperature. PSBs increased the diversity of soil bacteria through elevating soil dissolved carbon (DOC). Biochar altered soil bacterial community structure mainly by altering the level of soil electricity conductivity, DOC and bioavailable Cd. In addition, applying high-temperature PSBs increased the genus of bacteria that relevant to nitrogen cycling, such as Nitrospira, Nitrosotaleaceae and Candidatus_Nitrosotalea.
Display omitted
•Pyrolysis temperature of biochar affected bioavailability of Pb in soil obviously.•Biochar was more efficient in promoting Cd speciation transformation of Cd than Pb.•Biochar changed the bacterial community by altering soil DOC, EC and available Cd.•Feedstock type of biochar played key role in regulate bacterial diversity.•WSBs prepared at 700 °C was benefit to nitrogen cycle in soil.
OECD countries are at the forefront of sustainable development and working in several domains, including energy efficiency, environmental taxes, and the development of green technology. On this ...premise, the study’s main objective is to examine the impact of green technology , environmental taxes and natural resources on energy efficiency. The study used three dimensions of energy measurement: (i) energy efficiency, (ii) energy productivity, and (iii) energy intensity for OECD. An important feature of the study is the use of the “Rule of Law” to implement tax reforms and green technology. Malmquist–Luenberger and the super SBM-DEA are used to measure energy efficiency and productivity. France, Greece, Italy, Luxemburg, Sweden, Lithuania, Colombia, and Turkey’s energy efficiency range is between 1–1.5. Switzerland’s energy efficiency ranges from 1.5–2.0. The United States of America, Japan, the UK, Australia, Germany, Canada, and South Korea’s energy efficiency ranges are between 0.5–1.0. Beyond that, the higher energy-intensive countries are Canada, Estonia, South Korea, Finland, the USA, the Czech Republic, Australia, and the Slovak Republic. Regression analysis highlighted that the environmental tax and green technology are important drivers for improving energy efficiency and productivity and lowering energy intensity. The impact strength of environmental tax is higher than green technology to boost energy efficiency and limit energy intensity. Increasing rent on natural resources can raise the energy intensity and affects environmental sustainability. The study found that “the rule of law” is important for putting green technologies and tax reform into practice. Due to “the rule of law”, industries must abide by the green principle and pay attention to growth and the environment.
•Super SBM-DEA & Malmquist–Luenberger use for energy efficiency and productivity.•Two additional features are the inclusion of natural resources and energy intensity.•Examine the role of green technology and environmental taxes on energy efficiency.•Incorporated “the rule of law”, which is acknowledgeable to implement the policies.•“The rule of law” is important to implement tax reforms and green technology.
Studies on the association between estimated cardiorespiratory fitness (CRF) and changes in metabolic risk in the Chinese population are limited. This study aims to examine the associations between ...CRF and changes in metabolic risk.
We included 4,862 and 2,700 participants recruited from 28 provinces in the China Health and Retirement Longitudinal Study (CHARLS) in the baseline (Wave 1) and follow-up (Wave 4) analyses, respectively. CRF was calculated using sex-specific longitudinal non-exercise equations. Metabolic indicators included systolic blood pressure (SBP), diastolic blood pressure (DBP), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), and fasting plasma glucose (FPG) levels. The metabolic score was calculated as the number of changes in the above metabolic indicators above the 75th percentile of the distribution of changes (equal to or below the 25th percentile for HDL-C).
In the baseline analysis, CRF was negatively associated with SBP, DBP, TG, and FPG, and positively correlated with HDL-C after adjusting for age, smoking status, and drinking status (all P < 0.0001) in both males and females. In the follow-up analysis, higher baseline CRF was significantly related to a decrease in SBP, DBP, TG, FPG, and metabolic score (all P < 0.0005), and increased HDL-C (P < 0.0001) after further adjustment for corresponding baseline metabolic indicators. The associations remained significant after stratification by sex, except for the changes in HDL-C levels in females. Furthermore, improved CRF was associated with favorable changes in DBP, TG, HDL-C, FPG, and metabolic scores in all populations and males. Significant associations between changes in CRF and DBP, TG, and FPG levels were found in females.
Higher baseline CRF and improved CRF were associated with favorable changes in metabolic indicators.
To reveal the nonlinear mechanism of the tri-stable piezoelectric vibration energy harvester based on composite shape beam (TPEH-C) and its influence on the system response, the nonlinear restoring ...force and the nonlinear magnetic force are discussed and analyzed in this paper. The nonlinear magnetic model is acquired by using equivalent magnetizing current theory, and the nonlinear resilience model is obtained by fitting experimental data. The corresponding distributed parameter model based on generalized Hamiltonian variation principle has been established. Frequency response functions for the TPEH-C are derived according to harmonic balance expansion, and the influence of different magnet distances and different excitation accelerations on the response amplitude and bandwidth of the TPEH-C are investigated. More importantly, the correctness of the theoretical analysis is verified by experiments. The results reveal that the spectrum of composite beam shows hard characteristic and the depth of potential well is changed, which provides a new way to ameliorate the potential well of the TPEH-C. A suitable magnet distance enables the TPEH-C to improve the response amplitude and the effective frequency range. The results in this paper have a theoretical guiding significance for the optimal design and engineering application of the TPEH-C.
PDF
