A dataset of agro-meteorological disasteraffected area and grain loss in China(1949–2015)

As a big agricultural country,the People’s Republic of China has experienced a series of natural disasters since its founding,such as the 1959–1961 Great Famine,the 1998 floods and the 2008 snowstorm.Here we present a dataset summarizing four categories of meteorological disasteraffected area at provincial level in China from 1949 to 2015:mildly-affected area,moderately-affected area,heavily-affected area,and total affected area.Based on crop-planting data and natural disaster data,grain losses are also evaluated by using a grain loss assessment model.The dataset plays an important role in the future prediction,prevention,and reduction of agrometeorological disasters.

Typhoon events recorded in coastal lagoon deposits,southeastern Hainan Island

Coastal lagoon deposits provide evidence for the magnitude and frequency of past tropical cyclones prior to instrumental records and historical documentation.In the present study,we attempt to analyze the sedimentary records containing typhoon information for the northern South China Sea region.For this purpose,sediment cores were collected from two coastal lagoons in the southeastern Hainan Island,and were analyzed in laboratory to derive the data sets about grain size,organic and inorganic carbon contents,and deposition rates.The grain size and organic-inorganic carbon data were used to formulate the proxies of typhoon events.The deposition rates,as calculated using the CRS 210 Pb method,are around 0.5 mm/a for both lagoons,on the basis of which an age model is established.Within the cores,sedimentary layers associated with 35 typhoon events have been identified.On such a basis,a 350 year history of local typhoon activities is reconstructed by incorporating the 210 Pb dating results,typhoon-induced sedimentation patterns and the historical documents.A comparison of the frequency of typhoon occurrence with the regional climate records indicates that the observed changes in tropical cyclone activity patterns,as revealed by the lagoon sedimentary records,may be related to El Ni？o,Pacific Decadal Oscillation（PDO）,North Atlantic Oscillation（NAO）,sunspot,and other potential climate drivers that affect the tropical cyclone variability.This study demonstrates that the sedimentary record of storms can be analyzed in combination with historical documents,to provide meaningful information on past storm activities and their long-term variability.

Effect of the degree of milling on the microstructure and composition of japonica rice

The effect of the degree of milling(DM)on the distribution of the residual bran layer on the surface of rice grains and subsequent rice quality is essential for rice milling technology.This study used scanning electron microscopy(SEM)and energy dispersive spectroscopy(EDS)to examine the microstructure of japonica rice grains,the microstructural changes in different bran portions after milling,and the content and distribution changes of the elements and nutrients in rice after milling to identify the components that can quantify bran residue according to DM.The SEM results revealed that the thickness of the bran layer and the depth of the grooves in different parts of a rice grain varied,while the depth of the grooves differed between varieties.When DM was 12%,aleurone layer(Al)cells embedded in endosperm(En)remained in the dorsal area.It was speculated that this was the reason why there was no significant difference in bran degree when the DM estimated via grain weight loss increased from 10%to 14%(P>0.05).The EDS elemental mapping image showed the qualitative distribution of the elements,which was condensed in the bran and uniform in the En.The compositional changes revealed that milling caused the loss of rice nutrients,and the loss rate of DM at 0–10%was more serious than that of DM at 10%–14%.Higher DM(>10%)could remove marginal bran from the dorsal groove.Therefore,the crude protein,ash,crude fat,dietary fiber,vitamin B1(VB1),and vitamin B2(VB2)content did not change significantly(P>0.05),while the magnesium(Mg),kalium(K),and phosphorus(P)levels decreased substantially(P<0.05).The microstructural and compositional changes indicated that the DM estimated via the grain weight loss increased from 2%to 10%,with the bran decreasing progressively.The DM estimated via the grain weight loss increased from 10%to 14%,with minimal changes in the residual bran in the dorsal grooves of the rice grains,while the Mg,P,and K levels presented precise DM indices during the rice milling process.This result will provide a theoretical reference for the accurate evaluations of DM.

Review of grain threshing theory and technology

Threshing is the most important function of grain harvester.Grain loss and damage in harvesting are significantly related to threshing theory and technology.There are four kinds of threshing principles including impact,rubbing,combing and grinding.Four types of contact models between grain and threshing components have been constructed correspondently.Grain damage can be regarded as a function of peripheral velocity and contact pattern of impacting.Grain loss can be regarded as a function of contact pattern of rasp bars.Grain loss coming from cleaning and separation in the subsequent process of combing threshing was significantly decreased.Tangential and axial threshing technologies have been applied in grain threshing system widely.It showed that in the combined application,tangential rolls are used to accelerate grain flow,and axial rolls are used to increase threshing quality especially lower loss and damage.Conical concave may take the place of the traditional cylindrical one.With the development of sensor technology and communication technology,intelligent harvesting robot and automatic threshing system will be integrated together to improve grain quality and operation comfort.

Development of a monitoring system for grain loss of paddy rice based on a decision tree algorithm

China has the world’s largest planting area of paddy rice,but large quantities of paddy rice fall to the ground and are lost during harvesting with a combine harvester.Reducing grain loss is an effective way to increase production and revenue.In this study,a monitoring system was developed to monitor the grain loss of the paddy rice and this approach was tested on the test bench for verifying the precision.The development of the monitoring system for grain loss included two stages:the first stage was to collect impact signals using a piezoelectric film,extract the four features of Root Mean Square,Peak number,Frequency and Amplitude(fundamental component),and identify the kernel impact signals using the J48(C4.5)Decision Tree algorithm.In the second stage,the precision of the monitoring system was tested for the paddy rice at three different moisture contents(10.4%,19.6%,and 30.4%)and five different grain/impurity ratios(1/0.5,1/1,1/1.5,1/2,and 1/2.5).According to the results,the highest monitoring accuracy was 99.3%(moisture content 30.8%and grain/impurity ratio 1/2.5),the average accuracy of the monitoring tests was 92.6%,and monitoring of grain/impurity ratios between 1/1 and 1/1.5(>95.4%)had higher accuracy than monitoring the other grain/impurity ratios.Monitoring accuracy decreased as impurities increased.The lowest accuracy for grain loss monitoring was obtained when the grain/impurity ratio was 1/2.5,with monitoring accuracies of 88.2%,75.7%and 78.8%at moisture contents of 10.4%,19.6%and 30.4%.

Effect of niobium substitution on microstructures and thermal stability of TbCu7-type Sm-Fe-N magnets

This paper reports crystal structures, magnetic properties and thermal stability of TbCu7-type Sm（8.5）Fe（（85.8-x）Co（4.5）Zr（1.2）Nbx（x = 0-1.8） melt-spun compounds and their nitrides, investigated by means of X-ray diffraction, vibrating sample magnetometer, flux meter and transmission electron microscope. It is found that the lattice parameter ratio c/a of TbCu7-type crystal structure increases with Nb substitution, which indicates that the Nb can increase the stability of the metastable phase in the Sm-Fe ribbons. Nb substitution impedes the formation of magnetic soft phase a-Fe in which reversed domains initially form during the magnetization reversal process. Meanwhile, Nb substitution refines grains and leads to homogeneous micro structure with augmented grain boundaries. Thus the exchange coupling pining field is enhanced and irreversible domain wall propagation gets suppressed. As a result, the magnetic properties are improved and the irreversible flux loss of magnets is notably decreased. A maximum value 771.7 kA/m of the intrinsic coercivity H（cj） is achieved in the 1.2 at% substituted samples.The irreversible flux loss for 2 h exposure at 120 ℃ declines from 8.26% for Nb-free magnets to 6.32% for magnets with 1.2 at% Nb substitution.