Transactions of the Chinese Society of Agricultural Engineering, the 1st in Agricultural Engineering, is supervised by China Association for Science and Technology, and sponsored by Chinese Society of Agricultural Engineering. It aims to introduce the latest scientific achievements and developing trends of Agricultural Engineering and provides the academic developments abroad and domestic of the discipline. The scope covers agricultural water-soil engineering, agricultural information and electrical technology, agricultural products processing engineering.
The journal is included in EI, JST, Pж(AJ), CA and CSCD.
Editor-in-Chief Zhu Ming
Deputy Editor-in-Chief Wei Xiuju Zhang Ruihong Xi Weimin Wang Liu Wang Yingkuan Li Pingping Ying Yibin Tong Jin Yun Wenju Zhao Chunjiang Kang Shaozhong
Superfine grinding technology is a type of food processing used to produce powders with outstanding propertiessuch as high solubility, dispersion, adsorption, chemical reactivity and fluidity. In order to expand the application of the superfine grinding technology in food additive and pharmaceutical industries, the physicochemical properties of mulberry leaf micro-powders were investigated. Four types of mulberry leaf micronized powders were prepared by pulverizing its coarse through superfine grinding for different periods of time (2, 4, 6 and 8 h). The physicochemical properties of the micronized powders and the coarse powder were then compared and investigated. The results showed that superfine grinding could effectively pulverize coarse powder to different micro-sizes. With increased superfine grinding time, the particle size significantly decreased (
P<0.05). Furthermore, with narrowed particle size distribution, the specific surface area and bulk density significantly increased (
P<0.05); the angles of repose and slide and swelling capacity significantly decreased (
P<0.05); and the water and oil holding capacities, protein and polysaccharide solubilities and water solubility index improved to different extents. These indexes were tightly dependent on the particle size with absolute coefficients beyond 0.615 6. However, no significant difference was observed in flavonoid content among mulberry leaf particles (
P>0.05). The scanning electron micrography observations revealed the shape morphology of the fragmented mulberry granules. The physicochemical properties of micro-powder D milled at 8 h were more satisfying than micro-powders A, B, and C (milled at 2, 4 and 6 h, respectively). These results suggested that superfine grinding could improve some physicochemical properties of mulberry leaf powder, thereby enabling its applications as a functional food additive and food product, as well as a material for the pharmaceutical industry.
To reduce the costs and complexity of solar tracking system, a simple solar tracking control system and T-L type orientation detector are developed by analog circuit and photoelectric conversion principle. The tracking system is composed of bridge circuits and amplification circuits; it has the functions of manually adjusted tracking accuracy and manually working. It is used to drive 12 V DC gear motor, and it can be used for single-axis tracking, can also be used for dual-axis tracking. The tracking system only requires six common types of electronic components, which costs no more than CNY 10. In order to reduce external environment impact on tracking performance of the system, a T-L type orientation detector was designed for the tracking system. The L-type shading plate of the orientation detector was fixed to the L-type clapboard, therefore, the cross-section the shading plate and the clapboard showed a T-shape. Then, the clapboard was fixed to the substrate, and two sides of the clapboard were installed respectively with four light dependent resistors. Two were used to control the movement of east-west direction; the other two were used to control the movement of north-south direction. In addition, the back of the substrate was installed with two light dependent resistors. Also, it was paralleled respectively with the two light dependent resistors which were used to control the movement of east-west direction. One of the light dependent resistors was used for controlling the energy concentrator return orient in a next day; one of the light dependent resistor was used for balance another light dependent resistor behind the substrate. When using the system, the orientation detector was installed on a plane which paralleled to energy concentrator so that the orientation detector always synchronized to movement and energy concentrator. To test the performance of the tracking system, in this paper, the tracking performance of the system was analyzed by light spot detection experiments. The method of the experiment was that an inverted paper cup was attached to a piece of paper. A hole was drilled at the geometric center of bottom of the paper cup, and then the concentric circles with 2 mm interval were drawn on the paper. Then, the paper cup and the orientation detector were fixed to the bracket of the dual-axis tracking device. Thereby, observation was made on the light spot which was generated by a small hole in the bottom of the paper cup in the sunshine that was located on the first of several concentric circles on the paper. The observation time was the summer solstice at 09:00–16:00 in 2015, 10 min recorded once every spot position on concentric circles. Intervals of 10 min recorded a position of the light spot on concentric circles. The recorded dates of the light spot, the distance between the hole and the paper were used for a simple calculation, thus, the angle between the incident light of the sunlight and the normal direction of the paper was calculated. If the calculated angle was larger, the tracking error was greater and vice versa. After the analysis, we discovered that the angle error of the system increased as the time increased. The value of the angle error decreased first, and then increased. At about 13:00, the error angle has a minimum value of 0.14°; at 09:00 and 16:00, there was a maximum angle error, and its value was 5° and 2.9°, respectively. Theoretically, the angle between the normal direction of the paper and the incident light of sunlight should always be consistent, and the angle error does not change with time, but, the results of our experiments were different. After analyzing solar radiation, we discovered that the solar radiation along with time increased, the amount of radiation increased first, and then decreased. At about 13:00, the solar radiation had a maximum value of 972.9 W/m
2; at 09:00, there was a minimum, and its value was 443.6 W/m
2. The results showed that the tracking accuracy of the system was related to solar radiation, the higher solar radiation intensity was, the higher tracking accuracy would be. Its minimum tracking precision can reach 0.14° in one day. This tracking system is suitable for the situation for lower tracking accuracy and cost. It will establish the foundation for the popularization of solar tracking control system.
The improvement in the efficiency (running time) of the assimilation of spectral information into the crop growth model is an important researching aspect of applying the assimilation method at the regional scale. In this study, for reducing the running time while maintaining the performance, the temporal scale optimization of the assimilation was carried out by setting different step sizes of time phases at which the remote sensing observed values were assimilated into the coupling model of crop growth model WOFOST (world food studies) and radiative transfer model PROSPECT + SAIL. Based on the growth cycle of rice in Changchun, Jilin Province, China, four equidistant temporal scales (the step sizes of them were 5, 10, 20 and 30 days, respectively) and a crucial temporal scale (corresponding to the crucial growth period of rice) were set for assimilation. The time phases of crucial temporal scale were selected by taking the derivative of the time series curve of the leaf area index (LAI). The time phases corresponded to the extreme points and inflection points of LAI or LAI growth rate curves were also selected, which were the crucial periods of the growth process or the demarcation points of different growth stages. Then, the vegetation indices)—modified chlorophyll absorption ratio indices (MCARI1) were calculated from the spectral information on the corresponding time phases of each temporal scale, and then assimilated into the coupling model WOFOST + PROSPECT + SAIL to optimize the input parameters day of transplanting (IDTR) and temperature sum from sowing to transplanting (TSUMST) by using the assimilation algorithm- particle swarm optimization (PSO). Finally, the assimilation temporal scale was optimized by comparing the assimilation efficiency and the simulated accuracy of crop parameters, i.e., LAI, total above ground production (TAGP) and dry weight of storage organs (WSO), at the five different temporal scales. The results showed that the assimilation efficiency was raised and the accuracy gradually decreased as the step size of equidistant temporal scales increased. Although the number of the assimilation time phases at crucial temporal scale was greatly reduced compared with that at equidistant temporal scale with the step size of 10 days, the assimilation efficiency at the crucial temporal scale was promoted and the assimilation accuracy at the crucial temporal scale was close to it. Compared with the equidistant temporal scale with the step size of 20 days, the increasing rate of the assimilation efficiency at the crucial temporal scale was faster than the decreasing rate of the assimilation accuracy at the crucial temporal scale. On the premise of balancing the assimilation efficiency and accuracy, the temporal scale with the step size ranging from 10 days to 20 days and the crucial temporal scale were regarded as the reasonable temporal scales of assimilating the spectral information into the crop growth model for the growth simulation of rice. In this study, we proposed a novel method of selecting the time phases for assimilation by setting the equidistant temporal scales or extracting the crucial periods of crop growth process. It provided a reference for improving the application effect of the assimilation method at the regional scale by optimizing the assimilation temporal scale.
In order to study the effect on the performance of a single-cylinder diesel generator fueled with biodiesel using exhaust gas recirculation (EGR), the experiment was carried out with a single-cylinder air-cooled four-stroke diesel generator fueled with diesel and biodiesel under the EGR rates of 0, 16% and 28%, respectively, and the economy, the oxynitride (NO
x), hydrocarbon (HC) and carbon monoxide (CO) emission characteristics and the light absorption coefficient of exhaust were tested and analyzed. The secondary fuel tank was added on the diesel engine, and the fuel supply and test system as well as the EGR pipe were refitted. In the tests, diesel was the commercially available No. 0 diesel, and biodiesel was produced by Yunnan Ying-Ding Bioenergy Company from waste oil. The results showed that the appropriate EGR rate may slightly reduce diesel fuel consumption, for small load corresponded to a smaller EGR rate and high load corresponded to a larger EGR rate. The biodiesel fuel consumption was higher than diesel, and the average biodiesel fuel consumption in volume was about 9%, 10% and 17% higher than that of diesel, respectively, when using 0, 16% and 28% EGR rates. With the increase in EGR rate, the NO
x emission reduced. The NO
x emission could be reduced by about 17% and 35% when fueled with diesel, and could be reduced by about 10% and 24% when fueled with biodiesel under the 16% and 28% EGR rates respectively compared with that under the zero EGR rate. Moreover, the biodiesel NO
x emissions were about 6.5% and 17% higher than diesel under the 16% and 28% EGR rates respectively. With the increase in EGR rate, the HC emission increased obviously when fueled with diesel. The HC emission when using biodiesel was decreased by about 6% on average than that using diesel under the 16% EGR rate, and by about 28.5% under the 28% EGR rate. The CO emission was higher at no load, the lowest at middle–high load, and the highest at full load. The CO emission decreased gradually from no load to middle–high load, and increased significantly form middle–high load to full load. With the increase in EGR rate, the CO emission increased obviously when fueled with diesel and increased slightly when fueled with biodiesel. The biodiesel CO emission was slightly lower than diesel from low load to middle–high load under the 0 and 16% EGR rates, and obviously lower than diesel at every load under the 28% EGR rate. Moreover, the CO emission of biodiesel was about 24% lower than that of diesel on average under the 28% EGR rate. The light absorption coefficient of exhaust was lower at no load and middle–high load. The light absorption coefficient firstly increased obviously from no load to low-middle load, then decreased gradually to middle–high load, and then increased significantly to full load. With the increase in EGR rate, the light absorption coefficient increased when fueled with biodiesel; however, the trend was not obvious when fueled with diesel. The light absorption coefficient of biodiesel was higher than that of diesel at small and medium engine load. Compared with the vehicle diesel engine, diesel generator’s rotation speed was more stable, and the scope and frequency of load changes were lower. Therefore, biodiesel is more readily available in the practical application of diesel generators.
Inner Mongolia and its surrounding areas in the west are developing an intensive and large-scale sheep farming operation, in which sheep are bred with planting forage and placed in captive facilities. However, the breeding pattern of such operation needs a high level of animal welfare management. Considering that sheep makes different vocalization in different emergent situations, ewes’ vocalization can be used as an important indicator for ewes’ health monitoring and breeding welfare evaluation. In this study, the vocalization signals were evenly collected from 80 adult ewes of Small Tail Han sheep under three stress behaviors including searching lamb, hunger, and scare via a wireless audio surveillance device. Then, these continuous vocal signals of ewes were split into 1 200 single call signals using Audacity Acoustic Edit software. The band-pass filter and wavelet denoising methods were applied to preprocess those single sound signals. Six hundred of those sound signals, which were comprised of random selected 200 signals under each of the three stress behaviors, were analyzed to extract ewes’ acoustic characteristic parameters using auto-regressive (AR) power spectrum estimation and formant extraction methods. Therefore, six representative frequency characteristic parameters from AR power spectrum estimation method were extracted: the power spectrum density mean, the geometric mean, the median value, the trimmed mean, the mean absolute deviation, and inter quartile range, and characteristics parameters of the first, second, and third formant were extracted. Moreover, typical time-domain characteristic parameters such as signal maximum value, duration value, and interval value were taken as well. Then, these characteristic parameters were used to train the back propagation (BP) neural network model of ewes’ vocalization recognition, and the rest 600 vocal signals were used to test the effects of the recognition mode. The results demonstrated that the characteristic parameters of ewes’ vocal signals were obviously different under different stress behaviors. Furthermore, if BP recognition network was trained by formant parameters, the average correct recognition rate of ewes’ vocal signal was 85.3%, higher than the AR power spectrum estimation parameters of 81.0%. When BP network was trained by a combination of above two kinds of characteristic parameters, the average correct recognition rate was 93.8%, which meant that the performance of the combination parameters was better than another two methods. However, the average false positive rate still reached 6.2% because the ewes’ vocal signals under the same stress behavior had a certain degree of difference due to the different age and weight as well as sound volume strength. The results of this study also indicated that analysis of vocalization could be an indicator of different physiological conditions in sheep and may be an important role for understanding communications in ewes.
