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Fusarium wilt caused by Fusarium oxysporum f. sp. lycopersici (Fol) has severely decreased global tomato production. Organic amendments are widely applied to suppress Fol all over the world. However, the ways in which different amendments alter soil bulk microflora and thereby induce the suppression of Fol remain unclear. In this study, the effects of three organic amendments on the suppression of Fol in soil and the underlying mechanisms of those effects were studied. The organic amendments included in this study are rice straw, chicken manure compost, and vermicompost. High-throughput HiSeq sequencing and Real-Time PCR were used to determine the effect of the soil microbiota on the abundance of Fol. The abundance of Fol increased significantly with the duration of tomato cultivation. Vermicompost was the most effective organic fertilizer to suppress Fol in long-term continuous tomato cropping soil. Partial Least Squares Path Modeling revealed a strong positive relationship between the relative abundance of bacterial groups (including the genera Nocardioides, Ilumatobacter and Gaiella) and Fol inhibition. Soil chemical properties (pH, NH4+-N, soil organic matter and dissolved organic carbon) were positively associated with the genera Nocardioides, Ilumatobacter and Gaiella. Compared with chemical fertilizer and rice straw, vermicompost addition significantly increased soil pH, NH4+-N, soil organic matter and dissolved organic carbon concentrations in the soil with 20 years of tomato cultivation. Most importantly, the genera Nocardioides, Ilumatobacter and Gaiella were enriched in vermicompost, which may contribute to the propagation of these bacteria in the soil when vermicompost is added. This study provides a mechanistic framework that permits the exploration of specific functions at lower taxonomic levels. This may represent a novel approach in the management of crop pathogens via promotion of beneficial organisms.

Mechanically robust superhydrophobic coatings have been extensively reported using chemically susceptible inorganic fillers like SiO2, TiO2, ZnO, etc. for constructing micro-nano structures. Organic particles are good candidates for improving chemical resistance, whereas the synthesis of organic particles with well-defined and stable micro-nano structures remains exclusive. Here, an all-organic, cross-linked superhydrophobic coating comprising raspberry-like fluorinated micro particles (RLFMP) and fluorinated polyurethane (FPU) was prepared via thiol-click reaction. Benefiting from the robust micro-nano structure of RLFMP and the excellent flexibility of FPU, the coating could maintain superhydrophobic after severe alkali corrosion or mechanical damage, while the superhydrophobicity could be repaired readily by the fast recovery of micro-nano roughness and migration of branched fluoroalkyl chains to the coating surface. Our design strategy is expected to provide a good application of thiol-click chemistry. This article is protected by copyright. All rights reserved.

In order to obtain high tomato production, chemical fertilizers have been intensively applied in solar greenhouse in Northern China. This unreasonable use of chemical fertilizers always leads to so...

A greenhouse pot test was conducted to study the impacts of replacing mineral fertilizer with organic fertilizers for one full growing period on soil fertility, tomato yield and quality using soils with different tomato planting history. Four types of fertilization regimes were compared: (1) conventional fertilizer with urea, (2) chicken manure compost, (3) vermicompost, and (4) no fertilizer. The effects on plant growth, yield and fruit quality and soil properties (including microbial biomass carbon and nitrogen, [Formula: see text]-N, [Formula: see text]-N, soil water-soluble organic carbon, soil pH and electrical conductivity) were investigated in samples collected from the experimental soils at different tomato growth stages. The main results showed that: (1) vermicompost and chicken manure compost more effectively promoted plant growth, including stem diameter and plant height compared with other fertilizer treatments, in all three types of soil; (2) vermicompost improved fruit quality in each type of soil, and increased the sugar/acid ratio, and decreased nitrate concentration in fresh fruit compared with the CK treatment; (3) vermicompost led to greater improvements in fruit yield (74%), vitamin C (47%), and soluble sugar (71%) in soils with no tomato planting history compared with those in soils with long tomato planting history; and (4) vermicompost led to greater improvements in soil quality than chicken manure compost, including higher pH (averaged 7.37 vs. averaged 7.23) and lower soil electrical conductivity (averaged 204.1 vs. averaged 234.6 μS/cm) at the end of experiment in each type of soil. We conclude that vermicompost can be recommended as a fertilizer to improve tomato fruit quality and yield and soil quality, particularly for soils with no tomato planting history.

The problem of perimeter detection and monitoring has a variety of applications. In this paper, a hybrid system of finite states is proposed for multiple autonomous robotic agents with the purpose of hazardous spill perimeter detection and tracking. In the system, each robotic agent is assumed to be in one of three states: searching, pursuing, and tracking. The agents are prioritized based on their states, and a potential field is constructed for agents in each state. For an agent in the tracking state, the agent's location and velocity as well as those of its closest leading and trailing agents are utilized to control its movement. The convergence of the tracking algorithm is analyzed for multiple spills under certain conditions. Simulation and experiment results show that with the proposed method, the agents can successfully detect and track the spills of various shapes, sizes, and movements.

The photodegradation of aqueous methyl orange on MnTiO3 powder was studied in this work. The effects of initial pH and H2O2 on the photodegradation of aqueous methyl orange were studied. Single-phase MnTiO3 powder was synthesized by a sol–gel method. X-ray diffraction analysis shows powders have a particle size of 43.7 nm and rhombohedral pyrophanite structure. The photocatalysis experiments revealed that the efficiency of decolorization of the aqueous methyl orange (1 × 10−5 M) on the MnTiO3 powder is very fast in sunlight. The rate of decolorization appears larger at initial pH 5 and 9 than at pH 7. H2O2 (2%) can remarkably accelerate the decolorization at low initial pH.

This paper presents an information potential method for integrated path planning and control. The method is applicable to unicycle robotic sensors deployed to classify multiple targets in an obstacle-populated environment. A new navigation function, referred to as information potential, is generated from the target conditional mutual information, and used to design a closed-loop stable switched control law. The information potential is shown to obey the properties of potential navigation functions and to enable measurements that maximize the information value over time. The information potential is also used to construct a local roadmap for escaping local minima. The properties and computational complexity of the local roadmap algorithm are analyzed. Numerical simulation results show that the method outperforms other strategies, such as rapidly exploring random trees and classical potential field methods. © 2014 IEEE.

MSP430-based portable recorder could use in various occasion outside laboratory. Researchers no more need PC and other not portable instrument for measure and record the data about solar radiation, PV output and domestic hot water. Use DS12887 as real time clock, DS18B20 as the environment thermometer, has LED display and key for field use, 8-channel 4~20mA common standard signals sampling. All the sampling data were saved in SD card as CSV format. The device powered by rechargeable battery and could charge with solar cell, could long term record in the field.

Triple-junction solar cell achieved the highest efficiency. But the systems require concentration and accurate tracking to maintain the focus of the light on the solar cells as the sun move throughout the day. The tracking system was build with two-axis driven by motor with angle sensor feedback. The two angles were determined by solar positions which calculate from solar geometric algorithm. The driving system was closed-loop with PID control to reduce errors of the angle output. During the simulation and test, the tracker has been validated by the test data sets. The control system could meet the demand of the Fresnel concentration. With this tracking system could obviously improve the efficiency of the triple-junction solar cell.

The problem of perimeter detection and monitoring has a variety of applications. In this paper, a hybrid system with finite states strategy is proposed for multiple autonomous robotic agents with the purpose of hazardous spill perimeter detection and tracking. In the system, each robotic agent is assumed to be in one of the following states: searching, pursuing, and tracking. The agents are prioritized based on their states, and a potential field is constructed for agents in each state. The location and velocity of an agent in the tracking state as well as those of its closest leading and trailing agents are utilized to control its movement. The convergence of the tracking algorithm is analyzed for multiple spills under certain conditions. Simulation results show that with the proposed method, the agents can successfully detect and track the spills of various sizes and movements.Copyright © 2010 by ASME

Perimeter detection and surveillance by a distributed swarm of autonomous agents offers a solution in multiple cases where human safety or environmental protection is of concern. An algorithmic method is developed for detection and surveillance of one or more dynamic perimeters via distributed control under local-area sensing and communication. Local graphs among neighbors are formed based on proximity, at which point communication among graph members becomes possible. Hardware-in-the-loop mixed-simulation experiments validate the method utilizing iRobot Create® ground robots and a NaturalPoint OptiTrack vision system.Copyright © 2010 by ASME

In this paper, a novel artificial potential function is proposed for planning the path of a robotic sensor in a partially observed environment containing multiple obstacles and multiple targets. The sensor planning problem considered in this paper consists of planning the motion of a robot with an on-board sensor that is deployed in order to support a sensing objective, such as, target detection and classification, by gathering sensor measurements over time. An adaptive potential function approach is presented such that the sensor path accounts for prior information on the target geometry and information profit, by traveling a minimum distance.

The robot can navigate counterweights, clamps and some kinds of towers autonomously. The locomotion principle of counterweight-navigation is presented. Because of the deformation of the wire, the posture of the robot during navigation will be affected greatly. So a posture control strategy is proposed. Virtual prototyping technique is used to validate the strategy. It proves that the proper movement of the electric-box can adjust the robot centroid distribution efficiently. Driven torque and the power consumption of the whole system both decrease a lot. And the robot works more safely. Experimental results demonstrate that the robot can be applied to execute the navigation and inspection tasks. Also, the posture control strategy is proved again.

In this paper, the design of a controller is proposed for a multi-robot target search and retrieval system. Inspired by research in insect foraging and swarm robotics, we developed a transition mechanism for the multi-robot system. Environmental information and task performance obtained by the robot system are used to adjust individual robot’s parameters and guide environment exploration. The proposed control system is applicable in the solution of multi-target problem also where several robots may be needed to cooperate together to retrieve a large target. Simulations show that the task performance improves significantly with the proposed method by sharing information in parameter learning and environment exploration.Copyright © 2008 by ASME

Laser welding has a quite high demand on trajectory accuracy of articulated robot. To improve dynamic trajectory accuracy of articulated robots for laser welding, a novel 3D seam tracking method is proposed based on stereo visual feedback control. The method constructs a visual feedback control system with two convergent cameras mounted at the end of industrial robot. A tool coordinate system is constructed to transfer the end-link displacement of robot to that of the tool. A proposed GPI transform method, binocular vision technologies and a modified algorithm of line-line matching are utilized to calculate the positions of laser focus and weld seam, which makes the dynamic trajectory error between laser focus and weld seam can be calculated. The robot is finally commanded to move and decrease the trajectory error as soon as possible based on robot kinematics. Experimental results show that the method can effectively improve the trajectory accuracy of industrial robot for laser welding

The kinematic and dynamic behaviours of a robot manipulator on an elastic catenary cable were investigated. The dynamic equations of the robot and the cable were derived based on the Newton-Euler principle and Hamilton principle respectively. The recursive formulations describing the nonlinear and coupling dynamics relationship between the robot and the cable were presented. Based on the rigid-flexible coupling model proposed in this paper, a dynamic compensation technique with complementary control strategy was discussed which was implemented to adjust the posture of the robot and restrain the vibration that arise the flexible characteristics of the cable. The simulation and experiment results shown in this paper validate the effectiveness of the dynamic compensation.