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The experimental study investigates the takeoff characteristics of lower jet trajectory from the dovetail-shaped flip bucket under different inlet conditions. The experiment analyzes the influences of velocity and water depth on lower takeoff characteristics, especially the variation of takeoff angle of lower jet trajectory. The following items are addressed: 1) relationship between takeoff angle of lower jet trajectory and inlet velocity as well as inlet water depth; 2) characteristics of the takeoff angle as a function of changes of inlet Fr0; 3) the empirical formulas for calculating takeoff angle of lower jet trajectory. The results indicate that the effects of inlet conditions are significant on lower takeoff characteristics. Additionally, with the established empirical formulas, the calculated values of horizontal distance of lower nappe profile are in good agreement with the experimental data. [ABSTRACT FROM AUTHOR]

High N fertilizer and flooding irrigation applied to rice in anthropogenic-alluvial soil often result in N leaching and low use efficiency of applied fertilizer N from the rice field in Ningxia irrigation region in the upper reaches of the Yellow River. Sound N management practices need to be established to improve N use efficiency while sustaining high grain yield levels and minimize fertilizer N loss to the environment. We investigated the effects of Nursery Box Total Fertilization technology (NBTF) on N leaching at different rice growing stages, N use efficiency and rice yield in 2010 and 2011. The four fertilizer N treatments were 300 kg N ha−1 (CU, Conventional treatment of urea at 300 kg N ha−1), 120 kg N ha−1 (NBTF120, NBTF treatment of controlled-release N fertilizer at 120 kg N ha−1), 80 kgN ha−1 (NBTF80, NBTF treatment of controlled-release N fertilizer at 80 kg N ha−1) and no N fertilizer application treatment (CK). The results showed that the NBTF120 treatment increased N use efficiency, maintained crop yields and substantially reduced N losses to the environment. Under the CU treatment, the rice yield was 9634 and 7098 kg ha−1, the N use efficiency was 31·6% and 34·8% and the leaching losses of TN were 44·51 and 39·89 kg ha−1; NH4+-N was 5·26 and 5·49 kg ha−1, and NO3−-N was 27·94 and 26·22 kg ha−1 during the rice whole growing period in 2010 and 2011, respectively. Compared with CU, NBTF120 significantly increased the N use efficiency and decreased the N losses from the paddy field. Under NBTF120, the N use efficiency was 56·3% and 51·4%, which was 24·7% and 16·6% higher than that of CU, and the conventional fertilizer application rate could be reduced by 60% without lowering the rice yield while decreasing the leaching losses of TN by 16·27 and 14·36 kg ha−1, NH4+-N by 0·90 and 1·84 kg ha−1, NO3−-N by 110·6 and 10·14 kg ha−1 in 2010 and 2011, respectively. Our results indicate that the CU treatment resulted in relatively high N leaching losses, and that alternative practice of NBTF which synchronized fertilizer application with crop demand substantially reduced these losses. We therefore suggest the NBTF120 be a fertilizer application alternative which leads to high food production but low environmental impact. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: Chemical N input is essential for high rice yields. However, low recovery efficiency of chemical fertilizer N with flooding irrigation in the anthropogenic-alluvial soil resulted in N lost from the rice field in Ningxia Irrigation Region in the upper reaches of the Yellow River. With the technique of stable isotope 15N-traced urea, we conducted two years experiment to estimate the recovery efficiency and loss of applied chemical fertilizer in a rice field. The three fertilizer N treatments included 300kgha−1 (N300, the conventional application rate), 240kgha−1 (the optimized N application amount, N240) and no N fertilizer application treatment (CK). We estimated the recovery of 15N-labelled urea in grain, straw and root of rice and residues in soil profile. The 15N not accounted for in the plant and soil was presumably lost. The results showed that more efficient use of N fertilizer could allow current N application rates to reduce by 20%. This would still maintain crop yields while substantially reducing N losses to the environment. The high N fertilizer application increased the N uptake by rice derived from fertilizer, and the amount of N rice taken up from soil reduced correspondingly, which resulted in the higher N surplus in soil. Under the conventional irrigation and fertilizer management level, the recovery rate of 15N-labelled urea in rice–soil system was about 48–49%. The 15N-labelled fertilizer recovery in rice plant (N dff ) was 26–30%. In the paddy soil profiles of 0–90cm, the residual of 15N-labelled fertilizer in soil (N dfs) were 54–70kgha−1, and N residual rate in soils were 18–23%. The annual N loss from the rice field in the Irrigation Region was 28,865tons. The distribution of 15N abundance variability in different soil profile indicated that fertilizer N leached into the deep soil layers along with irrigation water as a result of continuous yearly rice planting. Optimization of nitrogen fertilizer can significantly reduce the amount of N residuals and N loss from the paddy field. Compared with N300, optimized nitrogen fertilizer application could decrease the loss of fertilizer N by 22–34kgha−1, and reduce the amount of N surplus by 26–33kgha−1 while the dry matter of rice increased 8–15% and N uptake by rice increased 2–6%. Considering the high food production and the minimum environmental threat, we should fully take into account the optimization application by reducing fertilizer N inputs. However, the interaction between irrigation management and N application rate on N use efficiency in alkaline anthropogenic-alluvial soil needs to be further studied. [Copyright &y& Elsevier]

A high rate of elemental sulfur (S 0 ) accumulation from sulfide-containing wastewater has great significance in terms of resource recovery and pollution control. This experimental study used Thiobacillus denitrificans and denitrifying bacteria incorporated with signal molecules (C6 and OHHL) for simultaneous sulfide (S 2- ) and nitrate (NO 3 - ) removal in synthetic wastewater. Also, the effects on S 0 accumulation due to changes in organic matter composition and bacteria proportion through signal molecules were analyzed. The 99.0% of S 2- removal and 99.3% of NO 3 - was achieved with 66% of S 0 accumulation under the active S 2- removal group. The S 0 accumulation, S 2- and NO 3 - removal mainly occurred in 0-48 h. The S 0 accumulation in the active S 2- removal group was 2.0-6.3 times higher than the inactive S 2- removal groups. In addition, S 0 /SO 4 2- ratio exhibited that S 0 conversion almost linearly increased with reaction time under the active S 2- removal group. The proportion of Thiobacillus denitrificans and H + consumption showed a positive correlation with S 0 accumulation. However, a very high or low ratio of H + /S 0 is not suitable for S 0 accumulation. The signal molecules greatly increased the concentration of protein-I and protein-II, which resulted in the high proportion of Thiobacillus denitrificans . Therefore, high S 0 accumulation was achieved as Thiobacillus denitrificans regulated the H + consumption and electron transfer rate and provided suppressed oxygen environment. This technology is cost-effective and commercially applicable for recovering S 0 from wastewater.

Biochar application is considered an effective method of reducing nitrous oxide (N 2 O) emissions in soil. However, the mechanism and temporal effect of different doses of biochar on N 2 O emissions is still obscure. Here, we conducted a two-year field experiment to test the effects of different input amounts and frequencies of biochar on soil N 2 O emissions in North China. Biochar was applied in six different treatments in a winter wheat and summer maize rotation system: applications of 0 t/ha biochar (C0), 2.25 t/ha biochar (C1), 4.5 t/ha biochar (C2), 9 t/ha biochar (C3), and 13.5 t/ha biochar (C4) each year, and a single application of 13.5 t/ha biochar (CS) in the first year. The results showed that biochar could inhibit N 2 O emissions, reaching 20.6% to 60.1% in the wheat season and 18.1% to 39.4% in the maize season. The inhibitory effect of biochar on soil N 2 O emissions was dependent on amount and time. C3 had the best results in the wheat season, although its inhibitory effect in the maize season was not as good relative to C4 due to the lower biochar application. In addition, CS significantly reduced (27.7%) the cumulative N 2 O emissions in the first year, although the inhibitory effect disappeared in the second year. Biochar increased the nosZ gene copy numbers and promoted a reduction of N 2 O in the soil via the denitrification process. In conclusion, the inhibition of N 2 O emissions during denitrification is an important factor for reducing soil N 2 O emissions by biochar, and the inhibition of biochar is influenced by the input amount and time., Competing Interests: Declaration of competing interest Hongyuan liu: Conceptualization, Methodology, Writing-Original Draft, Formal analysis. Hongbo li: Data curation, Writing-Review & Editing. Aiping Zhang: Writing-Review & Editing, Supervision. Md Arifur Rahaman: Writing-Review & Editing. Zhengli Yang: Supervision, Project administration., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Allocation scheduling for daily surgical cases is a decision-making process tasked to anesthesiologists and nurse managers in the operating room (OR). This manuscript focuses on three major areas: the classification and principles of allocation scheduling on workdays in China, flexible strategies of operational decision-making given differences in planned versus actual OR allocations, and perioperative quality implications of anesthesia scheduling. Improved quality and optimal decision-making in daily surgical case scheduling is seen with shift supervisor-based scheduling of staff and cases when compared with staff and case scheduling managed by the departmental director or chief resident., Competing Interests: Conflict Interests Disclosure: The authors have no conflicting interests to disclose.

This paper analyzed the present status of China agricultural water and soil environment. It was indicated that the agricultural water environment in this country was more serious, with the affected area being approximately 20% of the total farmland, and 5% of it being severely affected. More attention should be paid to the pollution of agricultural chemicals in soil environment. The impacts of industrial wastes, urban sewage and garbage, agricultural chemicals, and soil erosion on agro-environment were discussed, with the impact degree of these factors analyzed. The major problems in China agricultural environment melioration were presented, related researches and major countermeasures in this country and developed countries were reviewed, and relevant measures and suggestions on improving the agricultural environment quality of China were put forward.