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• The grain size of multidirectional rotary forged (MRF) Al7075 sheets after T6 heat treatment exhibited near-parabolic evolution. • The abnormal grain growth mechanism in MRF20 %+T6 condition and fine grain inheriting mechanism in MRF70 %+T6 condition are investigated. • The strength-plasticity collaborative improvement is achieved of multidirectional rotary forged Al7075 sheets during T6 heat treatment. • The strength-plasticity collaborative improvement mechanism is discussed based on experimental data and crystal plasticity simulation. Al7075 sheets are widely used in aerospace industry and their higher strength-plasticity collaborative improvement requirement is urgent. In this study, the microstructure inheriting the evolution and mechanical properties of Al7075 sheets during multidirectional rotary forging (MRF) and T6 heat treatment are analyzed. The results show that the average grain size exhibits near-parabolic evolution with increasing MRF deformation amount. MRF20 %+T6 (20 % MRF deformation amount+T6) condition possesses the largest grain size of 72.6 μm, and its abnormal grain growth mechanism is that the medium deformation energy and high deformation heterogeneity in MRF20 % deformed grains could cause asynchronous recrystallization behavior during T6 heat treatment, and the grains with comparatively higher deformation energy get recrystallized firstly and devour adjacent grains along preferred 〈011〉 or 〈223〉 misorientation axis. MRF70 %+T6 condition possesses the finest grain size of 14.2 μm, and its fine grain inheriting mechanism is that the uniformly high deformation energy in MRF70 % deformed grains causes uniformly rapid recrystallization, and rapidly recrystallized grains effectively suppress grain boundary motion from adjacent grains. With increasing MRF deformation amount, tensile strength and elongation values both exhibit near-antiparabolic evolution. MRF70 %+T6 condition possesses the largest tensile strength (563 MPa) and elongation (17.73 %), which increases by 8.27 % and 80.55 % compared to as-annealed+T6 (MRF0 %+T6) condition (tensile strength is 520 MPa and elongation is 9.82 %), respectively. The strength-plasticity collaborative improvement is mainly because the combination of effectively inherited fine grains, refined inclusion particles, and uniformly distributed fine η' particles after T6 heat treatment could promote smooth dislocation movement and coordinated slip behavior in most matrix grains, which contributes to the delay of stress localization and strength-plasticity collaborative improvement. [ABSTRACT FROM AUTHOR]

Soil salinization is threatening sustainable crop production in coastal saline regions. An integrated approach with combined tillage and mulching may be more successful than sole management practice (e.g., rotary tillage) for reducing soil salinity and improving crop productivity in coastal saline zones. We conducted a 3‐yr field experiment in maize (Zea maysL.) in the Yellow River Delta. We used four treatments: (a) rotary tillage to 15 cm (RT) (local farmers’ practice), (b) deep tillage to 25‐to‐30‐cm depth followed by RT (DT), (c) flat planting with the application of plastic mulch after DT (DM), and (d) ridge‐furrow planting together with plastic mulching after DT (DMF). These treatments were intended to improve soil properties and maize productivity, while increasing net returns. Grain yields were significantly increased by 18.5–20.9% under DMF and DM, nitrogen partial factor productivity (PFPN) by 18.5–20.8%, and net returns by US$103–124 ha–1, compared with RT. Grain yields with DMF and DM were also improved by 12.7–15.0%, PFPNby 12.8–15.0%, and net returns by $ 39–60 ha–1, compared with DT. Compared with RT, soil electrical conductivity (EC) and Na+concentration with DMF and DM were reduced by 16.2–75.4% and 19.0–78.2%; EC and Na+concentration were also reduced by 6.41–64.4% and 11.1–53.7%, compared with DT. These results demonstrate that combined tillage and mulching is an efficient integrated management approach for improving soil properties, promoting maize productivity, and increasing financial benefits in coastal saline zones. Ridge‐furrow with plastic mulch alleviated salt stress compared with rotary tillage.Ridge‐furrow with plastic mulch increased maize grain yield due to high ear number and biomass.Despite its high cost, higher yield with ridge‐furrow with plastic mulch improved net return.

The microstructural evolution law and the α variant selection relationship, as well as the deformation mechanism of the HIPed Ti–6Al–4V alloy, were investigated under the conditions of thermal compression and subsequent heat treatment. The results showed that lamellar α phase bending/kinking and fragmentation were the main spheroidizing mechanisms in the α+β phase region (850 °C and 920 °C), DDRX occurred as the restoration mechanism in the near-β region (940 °C), and the heterogeneous microstructure originated from the temperature gradient distribution. The strain rate clearly affected the dynamically recrystallized grain fraction and diameter, e.g … Both the fraction and diameter increased at a lower strain rate. The acicular α precipitated from β phase at 940 °C obeyed the Burgers relationship with β, and their misorientation angle intensified at approximately 60°. GBα formed by reducing the adjacent lamellar α misorientation angle; therefore, the GBα nucleation energy was lowest. The microhardness variation was relatively stable along the X direction at α+β phase region deformation, while oscillation appeared at near-β deformation, which can be explained by microstructure heterogeneity after thermal compression. For heat treatment, the trimodal microstructure appeared at 940 °C/0.001 s−1/60% thermal compression and subsequent 950 °C/1 h/WQ heat treatment, and the result might guide practical production to optimize mechanical properties.

Although efficient N fertilization has become widely accepted for sustaining or improving N use efficiency (NUE), many existing N fertilizer recommendations seldom consider N sources during implementation. To investigate the effect of N rates and sources on maize (Zea maysL.) production efficiency, soil quality, and economic benefits, a field experiment was conducted in the coastal saline area of China. The optimal N rate (ONR) treatment based on in‐season root‐zone N management reduced N application amount by 44% without grain yield losses and decreased the apparent N losses by 144 kg N ha–1compared with the local N management practice of farmers. Furthermore, the ONR treatment with ammonium sulfate (ONR‐AS) or calcium ammonium nitrate (ONR‐CAN) had higher maize grain yield and NUE than the ONR with urea (ONR‐urea) treatment. Compared with ONR‐urea, treatment with ONR‐AS or ONR‐CAN increased Ca2+content, decreased soil pH and Na+content, and thus imporved maize yield and NUE. Among the ONR treatments, the ONR‐AS treatment increased economic gains compared with the ONR‐urea treatment. This study suggests that an integrated N management can increase maize yield, NUE, and economic benefits and improve soil quality in the coastal saline soils.

Sustainable agricultural intensification to ensure global food security requires increases in both crop yields and nitrogen (N) productivity. Together, these requirements represent a considerable challenge, especially in saline regions where the high soil sodium (Na+) content limits crop growth. An integrated soil and crop management system (ISCM) may be more successful than procedures aimed at improving only soil quality (ISM) or crop management (ICM), or current local farmers’ practice for achieving sustainable intensification in coastal saline zones. In this study, we tested different management alternatives for their ability to improve soil quality, agronomic feasibility, and affordability over four harvests in a 2‐yr wheat (Triticum aestivumL.)–maize (Zea maysL.) rotation system in China. The ISM treatment with added cow manure and flue gas desulfurization gypsum reduced both Na+content and pH in the subsoil, thereby improving grain yields and N productivity. The ICM treatment (i.e., optimized plant density and N fertilizer management) also increased crop yields and N productivity. The ISCM treatment integrated procedures of the ICM and ISM treatments to achieve the best agronomic benefit by increasing yields of wheat and maize by 25.3 and 30.8%, respectively, and N productivity by 109 and 97.6%, respectively, while simultaneously improving soil quality by increasing both calcium ion (Ca2+) and soil organic carbon content, and decreasing Na+and pH in the subsoil. All three management alternatives increased economic benefits, and the ICM treatment was most valuable over the short term.

The major bottlenecks in an anaerobic digestion system are process instability and inactive microbes. The comparison of sodium lignosulfonate (SL) and its derived biochar (BC) additions for influencing the anaerobic process of glucose was extensively investigated at 37 ± 1 °C in a batch test. SL addition markedly reduced methane (CH4) yield (MY), resulting in 100 mL/g glucose, whereas the MY with SL-derived BC obviously increased, giving 415 mL/g glucose. SL could inhibit microbial activity versus BC. The modified Gompertz model reliably showed the relationship between SL or BC concentration and CH4production with a high correlation coefficient. SL could encapsulate microbes, causing a significant decrease in the total probabilities for microbial contacts. Some groups on the surface of SL, like sulfonyl and phenolic hydroxyl groups, were toxic to these anaerobes. However, the BC without sulfonyl group provided considerable pores for microbial immobilization, promoting direct interspecies electron transfer in the CH4bioevolution process.

Mixing of the upper ocean by the wind field associated with tropical cyclones (TCs) creates observable cold wakes in sea surface temperature and may potentially influence ocean heat uptake. The relationship between cold wake size and storm size, however, has yet to be explored. Here we apply two objective methods to observed daily sea surface temperature data to quantify the size of TC‐induced cold wakes. The obtained cold wake sizes agree well with the TC sizes estimated from the QuikSCAT‐R wind field database with a correlation coefficient of 0.51 and 0.59, respectively. Furthermore, our new estimate of the total cooling that incorporates the variations in the cold wake size provides improved estimates of TC power dissipation and TC‐induced ocean heat uptake. This study thus highlights the importance of cold wake size in evaluating the climatological effects of TCs. The wind field of a tropical cyclone can mix warm water downward, leaving a cold wake at the surface. This effect may influence ocean heat uptake within the climate system. We derive a novel oceanic metric of tropical cyclone size based on its induced cold wake using sea surface temperature data for a period from 2002 to 2011. The cold wake size agrees well with the wind field size determined from QuikSCAT surface winds. Furthermore, with the cold wake size incorporated, total cooling provides better quantifications of tropical cyclone power dissipation and cyclone‐induced ocean heat uptake. More reliable estimates of cyclone power dissipation and sea surface cooling may be useful for both understanding and forecasting impacts of tropical cyclones on the climate system. The size of the tropical cyclone wind field correlates reasonably well with the size of its mixing‐induced cold wakeWith the cold wake size incorporated, TC‐induced sea surface total cooling has a better correspondence with TC power dissipationCompared to sea surface cooling with a fixed cold wake area, the total cooling provides an improved estimate of TC‐induced ocean heat uptake

This study investigated the roles of calcium lignosulfonate (CL) and its derived biochar (BC) in biohydrogen production. CL was pyrolyzed at 250 °C to produce BC, and the main characteristics of the two materials were compared. A series of anaerobic processes were carried out at 54 ± 1 °C, and the results suggested that CL remarkably lowered the H2yield compared with that obtained with CL-derived BC. The highest H2yield (262 mL/g glucose) was obtained at 20 g/L, corresponding to an increase of 50.9%, whereas the lowest H2yield (110 mL/g glucose) occurred at 20 g/L and was 36.4% lower than that in the control group (173 mL/g glucose, without CL and BC). The CL-derived BC exhibited more pore structures than CL, providing more attachment sites for anaerobes. In addition, the high potassium, calcium, and magnesium contents and low sulfur dosage enhanced the microbial activity and process stability.

Tropical cyclones (TCs) are an important source of turbulent mixing for the upper ocean at low latitudes, causing sea surface cooling and subsurface warming. A new estimate of annually accumulated sea surface cooling and upper ocean diapycnal diffusivity induced by TCs is obtained by using quantified cold wake sizes, which were largely ignored by previous studies. Both the annually accumulated tropical cyclone‐induced sea surface cooling and upper ocean diffusivity on a global scale show a significant decreasing trend over the period of 1982–2016, at a rate of −0.09 ± 0.03 °C/decade and −0.03 ± 0.01 cm2/s/decade respectively. The strengthening of ocean stratification with global warming contributes to the decrease of sea surface cooling and mixing, while the changes of tropical cyclone characteristics (such as translation speed, intensity, number, lifetime and size) contribute differently in various ocean basins. The strong winds of tropical cyclones (TCs) greatly enhance upper ocean mixing. Cold water is mixed upwards, leaving cold wakes at the sea surface. Previous studies used cooling of the ocean surface induced by TCs to infer the upper ocean mixing, but some of their assumptions could lead to biases. In this study, based on quantified cold wakes, a new estimate of the sea surface cooling and upper ocean mixing induced by TCs is proposed. Based on observations, for the first time, we noted that the accumulated sea surface cooling and upper ocean mixing induced by global TCs have a significant decreasing trend over 1982–2016. This is primarily related to a more stable upper ocean and the decrease of tropical cyclone cold wake sizes with global warming. With quantified cold wake size, a new estimate of sea surface cooling and upper ocean mixing induced by tropical cyclones is providedGlobal tropical cyclone‐induced annually accumulated ocean cooling and mixing have been decreasing in recent decadesThe increased ocean stratification and the decreased cold wake sizes contribute to the decrease of accumulated ocean cooling and mixing With quantified cold wake size, a new estimate of sea surface cooling and upper ocean mixing induced by tropical cyclones is provided Global tropical cyclone‐induced annually accumulated ocean cooling and mixing have been decreasing in recent decades The increased ocean stratification and the decreased cold wake sizes contribute to the decrease of accumulated ocean cooling and mixing

The hot flow behavior, spheroidization, dynamic recrystallization (DRX) and fusing of lamellar ɑ phase for hot isostatic pressed Ti–6Al–4V titanium alloy was investigated at 950°C-900°C–850 °C with the total deformation amount of 70% during multi-pass deformation. The results show that all the flow stress value presented a peak value, followed by different flow softening extent. The flow stress is very susceptible to deformation parameters such as strain, strain rate and deformation temperature, and also the peak value decreased as the increase of temperature and the decrease of strain rate. The main softening mechanisms for different deformation pass are the DRX of β phase for one-pass deformation, spheroidization of lamellar α phase for two-pass deformation and DRX of α phase for three-pass deformation, respectively. The lamellar α spheroidization deformed in two-pass at 900 °C increased with decreased strain rate or the increased strain, and the maximum spheroidization fraction of lamellar α phase was 43% at 0.01s−1. The spheroidized mechanism of lamellar α phase is major give rise to the combined action of kinking deformation and element diffusion. Nevertheless, in the three-pass deformation process, the spheroidization degree did not significantly increase as increased strain, which principal give rise to the fusion of the same orientation of lamellar α phase. The fusion mechanism is the result of the joint action of the orientation of lamellar α phase and dislocation slip. And, the fraction of DRX of α phase is obviously higher than that of spheroidization in three-pass deformation, which is the main softening mechanisms.

Firstly, the hydrological and meteorological features of the upper reaches of the Yellow River above Tangnag are analyzed based on observation data, and effects of EI Nino and La Nina events on the high and low flow in the upper Yellow River are discussed. The results show El Nino and La Nina events possess consanguineous relationship with runoff in the upper Yellow River. As a whole, the probability of low flow occurrence in the upper Yellow River is relatively great along with the occurrence of El Nino event. Moreover, the flood in the upper Yellow River occurs frequently with the occurrence of La Nina event. Besides, the results also show dissimilarity of El Nino event occurring time exerts greater impact on high flow and low flow in the upper Yellow River, that is, the probability of drought will be greater in the same year if El Nino event occurs in spring, the high-flow may happen in this year if El Nino occurs in summer or autumn; the longer the continuous period of El Nino is, the lower the runoff in the upper Yellow River is.

A recent study noted reduced rainfall and cloud fraction over cold wakes induced by tropical cyclones, but a quantification of top‐of‐atmosphere (TOA) radiation change due to these cold wakes has not been attempted. Based on global TOA radiative flux observations, we show that TOA shortwave and longwave radiations increase by 0.76 W m−2(0.2%) and 0.74 W m−2(0.3%) over the cold wake area relative to local climatology, respectively. Due to the cancelation between the shortwave and longwave components, daily average TOA net radiation is only marginally modulated by cold wakes, but stands out in the day and night time average. In addition, the seasonal basin‐wide regulation of TOA net radiation by cold wakes can be up to 1.0 W m−2, locally comparable to the magnitude of radiative forcing due to man‐made aerosols. The regional impact of cold wakes on TOA radiations is therefore highly relevant and potentially important. The upper ocean stirred by tropical cyclones leaves a cold wake at the surface. Though the impact of cold wakes on ocean heat pumping, heat transport, and storm intensity were extensively explored for years, only recently have their modulation effects on rainfall and clouds been demonstrated. A further question is whether cold wakes significantly modify the local and seasonal basin‐wide energy budget. Here, we show that in observations, the top‐of‐atmosphere (TOA) shortwave and longwave radiations can be modified over cold wakes by ∼0.7 W m−2, while the daily‐averaged net radiation is unremarkable due to the cancelation between the shortwave and longwave components. However, the modulation effect of cold wakes on the local net radiation in the daytime and nighttime is much larger than the daily‐averaged radiation. Moreover, the basin‐wide radiative effect is one order larger than the local effect. The regulation of TOA radiation by cold wakes, particularly for the regional impacts and diurnal cycles, is therefore highly suggested for future assessment of Earth's energy budget. Local average top‐of‐atmosphere (TOA) longwave and shortwave radiations can be modulated by tropical cyclone cold wakes by ∼0.7 W m−2TOA net radiation change over cold wakes is small due to the cancelation between longwave and shortwave radiationsImpact of cold wakes on TOA net radiation differs over different basins due to different climatological mean radiations Local average top‐of‐atmosphere (TOA) longwave and shortwave radiations can be modulated by tropical cyclone cold wakes by ∼0.7 W m−2 TOA net radiation change over cold wakes is small due to the cancelation between longwave and shortwave radiations Impact of cold wakes on TOA net radiation differs over different basins due to different climatological mean radiations

Conductive materials play a vital role in electron transfer during the hydrogen (H2) fermentation process. In this work, a novel nitrogen-doped biochar (NDBC) was produced from corncob to improve biohydrogen production at 37 °C. Material analysis revealed that the nitrogen-rich biochar (BC) had a specific surface area of 831.13 m2/g, which was slightly lower than that of the corncob-derived BC (944.09 m2/g), while the electrical conductivity of the former was 13.91 times higher than that of the latter. The highest H2yield of 230 mL/g glucose was obtained at 600 mg/L NDBC, which was higher than the corncob-derived BC (159 mL/g glucose) and control (without any BC) (140 mL/g glucose) group yields. The microbial community structure illustrated that NDBC greatly reduced the abundance of Dysgonomonas(9.2%) and increased the abundance of Clostridium butyricum(10.9%). The NDBC and corncob-derived BC materials played obviously different roles: the former enriched the dominant bacteria and acted as an electron conduit promoting electron transfer, while the latter mainly provided favorable sites for microbial colonization. The results also indicated that cleaner energy production with a high H2yield was attained with the nitrogen-doped BC material.