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A high-precision mechanized seeding can greatly contribute to the vegetable production at present. In this study, a spotting glue-paper tape precision seeder was designed for the small seed vegetables, particularly combining the seed rope and printing seeding. Three components were also divided in the seeder, including the peristaltic pump glue, ratchet spotting glue, and seed metering device. Among them, the glue was a mixture of pregelatinized starch and water. Specifically, the glue volume and viscosity were the main factors affecting the number of adhered seeds. The glue point volume depended mainly on the rotation angle of the peristaltic pump during the movement. A pretest of seed adhesion was carried out to preliminarily determine the mass ratio of pregelatinized starch to water (less than 1:5), representing the glue viscosity. Furthermore, the frequency of pump and dispensing were analyzed to clarify the relationship between the peristaltic pump and ratchet speed, where the number of ratchet teeth was determined to be 4. As such, the matching was realized between the peristaltic pump and ratchet spotting glue. The ratchet profile was also designed, according to the spotting glue motion. A theoretical analysis was made on the movement of seeds in the seed guiding tube. It was found that the aggregation effect of seeds on the paper tape relied on the length and cross-sectional angle of the seed guiding tube, as well as the rotation speed of the socket wheel. The seed guiding tube was then optimized for the optimal structural parameters. A Box_Behnken test was also carried out, where the length and cross-sectional angle of the seed guiding tube, while the rotation speed of the socket wheel was taken as the test factors, whereas, the percentage of seeds in the effective area on the paper tape was taken as the test index. The results showed that the percentage of seeds in the effective area on the paper tape was 57.23%, when the length of the seed guiding tube was 56 mm, the section angle was 35°, and the rotation speed of the seed metering wheel was 30 r/min. An adhesion test was also performed on the Shanghai Qing 605 seeds with a diameter of 1.5-2.0 mm. The test factors were then selected as the roller angle of the peristaltic pump and the mass ratio of pregelatinized starch to water. An optimal combination of parameters was achieved, including the size of the glue point, and the mass ratio of pregelatinized starch to water. Once the roller rotation angle was 10° and the mass ratio of pre-gelatinized starch to water was 1:6, the single seed rate of glue point adhesion to seeds reached 97.4%. The adaptability test was also carried out on the whole machine on the working performance of different varieties of small seed vegetables. It was found that the single seed rates of Shanghai Qing 605 and Siji Chinese cabbage seeds were greater than 95% under the working speed of 0.5-1.5 m/s, whereas, the coefficient of variation of plant spacing was less than 10%, fully meeting the requirements of precision sowing indicators that specified in the standard NY/T1143-2006. Therefore, the single seed rate and the working efficiency of the improved seeder increased by 3.53%, and 50% than before. [ABSTRACT FROM AUTHOR]

Soil water characteristic curve (SWCC) can show the soil water holding capacity, and is the relationship between the soil matric potential and saturation. The expansive soil has the characteristics of strong swell-shrink, developing fissures and over consolidation, especially under drying-wetting cycles. Its water holding capacity, which has an important impact on the soil properties, is totally different from the capacity of full soil. Therefore, how to exactly obtain the matric suction of expansive soil under drying-wetting cycles is very important to analyze the characteristics of mechanics and deformation of expansive soil. In order to analyze the change rule of matric suction of expansive soil under drying-wetting cycles, the artificial rainfall and evaporation was applied in drying-wetting tests of expansive soil. The specimens sized at 102 mm × 40 mm (diameter × height) were made by compaction apparatus and the initial dry density was 1.68 g/cm3. All the specimens were saturated after compaction and undergoing drying-wetting cycles in constant temperature (22 ℃) environment. The small electric fans were adopted to increase the rate of evaporation until the mass of specimens was kept constant under the condition of drying. Then the water vapours were sprayed to the surface of specimens by humidifiers until the process of infiltration stopped under the condition of wetting. That is one drying-wetting cycle so far. In this paper, 4 set of experiments under drying-wetting cycles were carried out and the cycle times were 1, 2, 3 and 4 respectively. Then 11 specimens sampled by cutting rings (61.8 mm × 20 mm (diameter × height)) in different volumetric water content were obtained in each process of drying and wetting respectively. The matric suction of each specimen was measured with filter paper of Whatman No. 42 and then the SWCCs were obtained under drying-wetting cycles. The corresponding air-entry values and residual values in different drying-wetting cycle times were calculated from SWCC. Ulteriorly, the different SWCCs obtained in different drying-wetting cycle times were fitted by the Fredlund SWCC model. Based on the above analysis, an SWCC model of expansive soil considering drying-wetting cycle effect was established finally. The results showed that: 1) With the increase of drying-wetting cycle time, the air-entry value of expansive soil was evidently reduced. Compared with the air-entry value (134.5 kPa) of expansive soil undergoing one drying-wetting cycle, the air-entry value was 58.5 kPa and reduced by 56.5% undergoing 4 drying-wetting cycles. The most effect of drying-wetting cycles on air-entry value occurred in the first cycle. 2) With the increase of drying-wetting cycle time, the residual value of expansive soil was also reduced. Compared with the residual value (1040.5 kPa) of expansive soil undergoing one drying-wetting cycle, the residual value was 528.5 kPa and reduced by 49.2% undergoing 4 drying-wetting cycles. Moreover, the residual value is reduced evidently after undergoing one drying-wetting cycle and it cannot yet be stabilized with the increase of drying-wetting cycle time. That means the effect of drying-wetting cycles on ari-entry value is much greater than on residual value. 3) The fitted parameters in the SWCC model of expansive soil considering the effect of drying-wetting cycle have a good linear correlation with the drying-wetting cycle time. With the increase of drying-wetting cycle time, the soil air-entry value and change rate of water content reduce while the residual value increases gradually. The results can provide a reference for the further analysis on soil matric suction and its application in engineering. [ABSTRACT FROM AUTHOR]

A photoelectric detection method based on paper-based microfluidic chip in pesticide residues is proposed because the existing equipment has the problems of high cost, low degree of automation and large amount of reagent consumables. We design a kind of simple, portable, inexpensive paper-based microfluidic chip, whose bridge composite structure can enhance the uniformity of the color reaction of microfluidic enzyme, and also design the light path and circuit structure suitable for optical absorption reflection detection. The signal amplifying circuit and filter circuit are built to eliminate the interference of clutter and noise in photoelectric detection. Finally, a portable detection system of pesticide residue is established, which is an integrated test platform of the chemical reaction, the reflection effect in light absorption and the control of environment parameters. We observe and optimize the light source, chip placement angle, temperature and other process parameters of test platform in Jiangsu University in 2016. The reflection absorption effect of red LEDs (light-emitting diodes) is tested to be the best among the LEDs with different colors through detecting the paper-based chip color area. The response effect of the system is better when the angle is 10 according to the chip placement angle and reflected voltage data of photoelectric detection during the reaction. It is concluded that light absorption is the most under 35 ℃ and the chemical reaction is the most sufficient via comparing the color effect of the biochemical reaction of enzyme inhibition under different temperatures. We design different concentrations of pesticides, which are used for biochemical reactions of enzyme inhibition in different paper-based microfluidic chips. The resulting product displays blue color region in the paper-based chip, which can be characterized by the color of the different concentrations of pesticides. We use the photoelectric detection device to detect the color zone of the chip; the reflected voltage data can be obtained with this method, which correspond to different concentrations. Based on the experimental data, the model is established by the reflected voltage and the concentration of pesticide. The pesticide residues of test samples can be analyzed quantitatively based on the detection model. It can be concluded from the experimental results that with the method of photoelectric detection, the minimum detection limit of pesticide residues (trichlorfon and parathion) can reach 0.05 mg/L, meeting the national standard, and the resolution can reach 0.002 mg/L, much higher than that with the traditional method. Within the concentration range of pesticide residues, compared with the pesticide residues detector and the rapid detection card, the detection limit for the photoelectric detection is equivalent, but the consumable items are respectively 5.21% and 41.7% of the former 2 methods, and the reduction of time is respectively 23% and 33%. We propose a kind of pesticide residues detection system, which combines the photoelectric detection system and the paper-based microfluidic chip, and possesses the advantages of easy integration and low consumption. The research provides the theoretical basis and realistic foundation for making the pesticide residues detection develop to be portable and universal. [ABSTRACT FROM AUTHOR]

This study aims to improve the utilization rate of abandoned corn bracts, while decreasing the production cost of the bag of fruit cultivating in sustainable agriculture. Five representative bags of fruit cultivating were collected in the market as the controlled samples, including the plastic film bag A, special bag B for grape, one-, two- and three-layered bag C, D, and E. The basic structural characteristics of controlled samples were firstly analyzed. Then, alkali cooking was used to degum the corn bracts for the extraction of fibers. Subsequently, the corn bract fibers were cut into (5±0.5) mm long, thereby mixing evenly with the waste paper scraps in a ratio of 1.5:1. The wet mesh forming was adopted to prepare the fruit-cultivating bag material F. The mechanical properties of material F were tested after fabrication. The experimental results showed that the prepared material F behaved a strong tensile resistance, where the tensile loads for the dry and wet material F were up to 20.02 N and 13.79 N, respectively. Moreover, the retention rate reached 68.9% for the tensile load of wet material F. Furthermore, an excellent extension performance was achieved for the high requirements of mechanical properties in the fruit bagging. A scanning electronic microscopy (SEM) was adopted to observe the microstructure of the prepared materials F and the controlled samples in the market, further to analyze the distribution of holes in the matrix. The bagging properties were also measured, including air permeability, heat-insulating property, shading property, and water management ability. The experimental data demonstrated that the fruit-cultivating bag material F presented an excellent air permeability. Specifically, the air-flow rate and permeability of material were 73.5 mm/s and 173.7 L/m2 •s, respectively. In contrast to the controlled samples, the maximum air-flow rate and permeability were only 2.5 mm/s and 0.3 L/m2 •s, respectively. In addition, the heat loss of boiling water was about 265 kJ, when the prepared material was used to keep the boiling water for 60 min. The transmittance of the material F was about 0.4 % in the visible light range, and 0.09 % in the ultraviolet light range. The shielding properties showed that the prepared material ensured the photosynthesis of fruits during the growth process. Meanwhile, material F was expected to protect the fruit from ultraviolet light burning. Excellent ability of water conductivity was also achieved, where the core suction height reached 31 mm within 30 min. As such, the water in the fruit-cultivating bag during rainy days discharged quickly to enhance the quality of fruit products. Low wet evaporation indicated that the water retention performance was obviously better than that of the special bag B for the grape in the market. Most significantly, the thermal insulation performance of the new fabricated material was better than that of the controlled samples in the market. [ABSTRACT FROM AUTHOR]

Most of the articles about the degradation performance of biodegradable nursery pots were focused on degradation morphology, strength of pot body, changes of soil, effect of raising seedings and so on. However, it rarely study on degradation rate, molecular structure of degradation process and changes of crystallinity. In order to study the degradation performance of biodegradable nursery pots, three types containing paper pot, undecomposed straw pot and decomposed straw pot were used to carry out the experiment in this paper. The degradation rate, molecular structure and crystallinity were evaluated and analyzed through the experiments of degradation test in soil, Fourier infrared scanning and x-ray diffraction. It is necessary to have a further research on degradation performance of biodegradable nursery containers and mechanism of degradation. The results showed that the degradation rate of paper pot with the best degradation property was growing at a rate of about 2 times. The maximum degradation rate was up to 85%. The undecomposed straw pot has always maintained a stable and increasing degradation rate. The undecomposed straw pot with degradation rate of 78% in the eighth week was higher than that of decomposed straw pot. The changes of mass loss and degradation rate were likely to be affect by a variety of microbial community structure. On the one hand, due to partial degradation of cellulose and semicellulose, the remaining part kept stable performance. On the other hand, the changes of microbial structure and activity affected the degradation performance. By comparison, FTIR absorption strength of the biodegradable nursery pots was decreased in different degree due to the changes of molecular structure during biodegradation. The absorption strength of paper pot decreased in the location of 3340 cm-1 and 2920 cm-1 indicated that the degradation of cellulose and hemicellulose. In addition, the relative peak of 1640 cm-1 and 1460 cm-1 decreased with the further degradation, showing that lignin was degraded in the biological reaction. The peak strength of CH stretch band was enhanced obviously at 892 cm-1. It showed that the substitution reaction of aromatic ring was an important part of the degradation process of lignin. The main group structure of undecomposed straw pot and decomposed straw pot were basically the same. The absorption peaks strength decreased at 3340 cm-1 and 1010 cm-1 might be due to the oxidative decomposition of benzene methanol unit. The peak strength of CH stretch band decreased at 2920 cm-1 probably because of the decomposition of carbohydrates and the fracture of partial fatty chain. The degradation of lignin resulted in the decrease of peak strength of 1650 cm-1. The x-ray diffraction peak intensity of paper pot with the best degradation property decreased obviously after 8 weeks test. The diffraction peak disappeared at 2 θ=15.6°. At the same time, The intensity of diffraction peak decreased at 2 θ=22.5°. In addition, it appeared new diffraction peaks at 2 θ=27° of undecomposed straw pot and decomposed straw pot. This might be due to the changes of crystalline which caused by the degradation of straw. The biodegradable nursery containers with excellent degradation property could improve the problem of environmental pollution effectively. [ABSTRACT FROM AUTHOR]

Compared with other methods of cultivating corn seedlings, seedlings growing in paper tube have the advantage of high efficiency in transplanting. To solve the problems of labor intensity, low efficiency and high cost of conventional transplanting, a transplanter for corn seedlings growing in paper tube was designed in the paper. The critical part of the transplanter is the transplanting disc, which affects the operation performance of the whole machine. To determine the structural and working parameters of the transplanting disc, the physical parameters of paper tube seedlings were measured, the motion process and velocities of paper tube seedlings in the transplanting disc were analyzed. The trajectory equation of paper tube seedlings was designed, and the effects of the structural and working parameters on the motion trajectory of paper tube seedlings were simulated using MATLAB. The optimal parameters were determined, i.e., the rotary speed of the transplanting disc (w) is 7 rad/s, the distance between the center of seedling tube and transplanting disc (L) is 275 mm and the angle that the seedling tube rotating with the transplanting disc (α) is 80°. Field experiments were conducted in a research field at Gu'an county, Hebei province. The working speed of the transplanter was maintained at 5 km/h and the theoretical seedling spacing was set as 200 mm. The experiments were repeated three times. 100 seedlings in the middle of 200 seedlings which were transplanted one time were taken as samples. The upright degree, seedling depth and seedling spacing were measured and their qualified indices were calculated to evaluate the working performance of the transplanter. The results showed that the percentage of upright seedlings is 91%, the qualified index of seedling spacing is 92.6%, and the qualified index of transplanting depth is 79.3%. All the indices are better than standard values and the performance of the new transplanter is better than that of conventional transplanting machines. The coefficient of variation of transplanting depth is 7.4%, which means the transplanter has good uniformity of transplanting depth. The percentage of upright seedlings indicates that the theoretical analysis method for determining the structural and working parameters of the transplanting disc used in this research is feasible. The transplanting depth of seedlings was influenced by soil condition. To obtain desired transplanting depth, the depth of loose soil layer must be deeper than the transplanting depth when preparing field. Although the qualified index of seedling spacing is more than 90%, the coefficient of variation of seedling spacing is as high as 21%. The main reason is that the distances between seedlings were changed in seedling delivery system before them coming into the transplanting disc. So the seedling delivery system should be optimized in further study. The data revealed that the transplanter for paper tube corn seedlings performed well in actual operation and the transplanting efficiency can meet the needs of Chinese peasants properly. The new design and the theoretical analysis method in this research can provide a reference for design and application of transplanters. [ABSTRACT FROM AUTHOR]

Seedling transplanting technologies can greatly improve crop yield, in order to further improve the seedling planting quality of transplanting machine, the working parameters of disc type planting apparatus of corn transplanter were analyzed, the influence law of working parameters on the plant quality was studied through soil-bin test. The orthogonal rotation combination test was conducted, which took location of furrow opener, the depth into the soil of furrow opener and backfill shovel inclined angle as input variables, and took upright degree and coefficient of variation of row spacing as response. By using Design-expert regression analysis method and response surface method, the effects of three factors on test indexes were analyzed. The results indicated that with the parameters of furrow opener position was 50 mm, backfill shovel inclined angle was 40°and the depth into the soil of furrow opener was 115 mm, the percent of pass of upright degree was higher than 93%, the coefficient of spacing deviation was less than 12%. The optimized parameters can meet the need of corn transplanting mechanical performance and provide basis for further research. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)