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Preventing extinction is one of the greatest challenges facing the global community. Nursery stock breeding is an effective means to restore endangered species, such as Horsfieldia hainanensis Merr., with difficulty in natural regeneration period. In this study, we investigated the optimum combination of irradiance and nitrogen for the cultivation of H. hainanensis seedlings by comparing twenty treatments with different combinations of irradiances (100, 67.5, 45.7, 15.6 % of full natural irradiance) and five levels of N supply (0, 1.8, 3.6, 5.4, 7.2 g plant-1). We found that the growth and photosynthetic efficiency of seedlings under full irradiance were significantly inhibited compared with shaded seedlings. Under full irradiance, a lack of N resulted in reduced chlorophyll (Chl) synthesis, causing lower photosynthetic efficiency and an imbalance in metabolism. Proper shading (67.5 and 45.7 % of natural irradiance) and N addition (1.8 - 5.4 g plant-1) promoted root development, increase Chl content and photosynthesis, and ultimately the accumulation of larger amount of biomass. The biomass of the shaded seedlings was mainly distributed to aboveground tissues, while seedlings exposed to stronger radiation accumulated greater root biomass. Therefore, the best seedling management for this species is a combination of 67.5 % of natural irradiance and moderate N supply (4.6 g plant-1). [ABSTRACT FROM AUTHOR]

In order to explore the effect of exogenous 24-epibrassinolide (EBR, 0.1 µM) application on photosynthetic parameters in response to different light intensities and CO2 concentrations in maize seedlings under NaCl stress (180 mM), this study investigated the light response curve, CO2 response curve, and diurnal variation of photosynthesis of maize seedlings under NaCl stress. Maize cv. Jinlai 318 was used as the material, and the leaves were sprayed with 0.1 µM EBR. Net photosynthetic rate (PN), stomatal conductance (gs), intercellular CO2 concentration (Ci), and transpiration rate (E) were determined. The results showed that the light response curve, CO2 response curve, and diurnal variation trend under the four treatments (180 mM NaCl, 0.1 µM EBR, 180 mM NaCl with 0.1 µM EBR, pure water) were similar. The light saturation point of the leaves under NaCl stress was the lowest (about 1 031 mol m-2 s-1), and that in the control group (without stress) was the highest (about 1 344 mol m-2 s-1). When the light saturation point was reached (1 030 -1 350 mol m-2 s-1), the maximum PN under NaCl stress was the lowest (about 15.15 µmol m-2 s-1), while that under EBR treatment, it was the highest (about 19.86 µmol m-2 s-1). NaCl stress significantly reduced chlorophyll a, chlorophyll b, and carotenoid content and chlorophyll a/b ratio, while chlorophyll content significantly increased after EBR treatment. These results showed that exogenous EBR could effectively alleviate the damage to maize seedlings under NaCl stress, delay the light saturation phenomenon, and improve the photosynthetic capacity of maize. [ABSTRACT FROM AUTHOR]

In order to solve the scheduling and path planning problems of multi-AGVs in an intelligent manufacturing workshop, it is necessary to consider loading, unloading, and transporting the workpiece of each AGV at the same time. A step task scheduling and path optimization mode of AGV is proposed. The process is as follows: Firstly, a mathematical model algorithm and a material transportation task allocation algorithm based on the urgency degree of workpiece processing were established for the optimization objective, and all workpiece transportation task sequences between shelves and processing equipment were assigned to the corresponding AGV to generate the initial feasible path of each AGV. Then, the AGV collision detection and anti-collision algorithm are designed to plan the global collision-free walking path of multi-AGVs in the workshop, and the path can be dynamically adjusted according to the delivery task. The model is solved by a heuristic algorithm ant colony algorithm and MATLAB coding. Finally, an example is given to verify the effectiveness of the method, which can effectively solve the task allocation of multi-AGVs and avoid collision path planning based on the transportation task sequence, and improve the work efficiency of AGV. This research can provide a theoretical basis and practical reference for realizing multi AGVs collaborative scheduling by using AGV automated material transport system in an intelligent production workshop. [ABSTRACT FROM AUTHOR]

The near-nozzle structure of several nonevaporating biodiesel-blend sprays has been studied using X-ray radiography. Radiography allows quantitative measurements of the fuel distribution in sprays to be made with high temporal and spatial resolution. Measurements have been made at different values of injection pressure, ambient density, and with two different nozzle geometries to understand the influences of these parameters on the spray structure of the biodiesel blend. These measurements have been compared with corresponding measurements of Viscor, a diesel calibration fluid, to demonstrate the fuel effects on the spray structure. Generally, the biodiesel-blend spray has a similar structure to the spray of Viscor. For the nonhydroground nozzle used in this study, the biodiesel-blend spray has a slightly slower penetration into the ambient gas than the Viscor spray. The cone angle of the biodiesel-blend spray is generally smaller than that of the Viscor spray, indicating that the biodiesel-blend spray is denser than the Viscor spray. For the hydroground nozzle, both fuels produce sprays with initially wide cone angles that transition to narrow sprays during the steady-state portion of the injection event. These variations in cone angle with time occur later for the biodiesel-blend spray than for the Viscor spray, indicating that the dynamics of the injector needle as it opens are somewhat different for the two fuels. [DOI: 10.1115/1.3094023]