An automatic machine able to perform variable rate application of flame weeding: design and assembly

This paper describes the design and development of an automatic machine able to perform Variable Rate Application of cross flaming in maize fields. The VRA flaming machine was designed to remove weeds mechanically from the inter-row area and perform selective and targeted cross flaming along the crop rows. The mechanical treatment will be performed in a continuous way, even without weed presence. On the contrary, cross flaming on the maize rows is applied selective and automatically only if weeds are presence. Flame weeding is applied by means of prismatic burners fed by Liquefied Petroleum Gas, able to treat 25 cm wide strips of soil surface including crop rows. Flaming can be used selectively in maize, which can tolerate the heat released from the burners. Mechanism of morphological tolerance is the presence of many layers of the outer leaf tissue protecting the inner growing point. A low or a high LPG dose can be chosen automatically according to the weed cover percentage detected by a weed detection system. The ignition system of the VRA flaming machine is almost instantaneous and the complete flame in the burner is obtained in 0.4 s. The machine is provided with an automatic steering system in order to avoid damaging the maize plants with the rigid tools used for mechanical weed removal. The VRA flaming machine is a new technology for precision agriculture and was designed and built within the “Robot fleets for Highly Effective Agriculture and forestry management” (RHEA) Project, funded by EU, aimed to develop a fleet of heterogeneous autonomous robot units in order to perform site-specific treatments related to crop protection in different agricultural scenarios

An autonomous ground mobile unit for the precision physical weed control.

In this paper the design, the main characteristics and the automation systems of innovative autonomous ground mobile units (GMU) for physical weed control (PWC) in maize are described. The machine will be created within the activities of the European Project RHEA (Robot fleets for Highly Effective Agriculture and forestry management), that aims to produce different prototypes of autonomous terrestrial and aerial robot able to perform several activities related to the general crop protection in different agricultural scenarios. The first autonomous ground unit machine was designed in order to perform a mechanical and thermal treatment removing weeds from the inter-row crop space and applying in-row selective and precision flaming by means of two crossed LPG rod burners. By means of some modifications of the tools it will be possible to realize also an autonomous unit for the precision broadcast flaming application. In this case the design involves a replacement of the mechanical tools working in the inter-row space with 50 cm wide burners able to perform flaming at different intensities according to weed cover detected by the perception system of the robot. The working width of both the PWC machines will be of 4.5 m, thus covering five entire maize inter-row spaces of 0.75 m each and 2 half inter-row space of 0.375 m each. The correct position of the tools (mechanical and thermal) will be guaranteed by an automatic precision guidance system connected and supervised to an image based row detection system. Each working elements will be provided by two crossed 0.25 m wide rod burners, hitting one side of each crop row. The flame should hit the weeds growing in the “inrow” space (a 0.25 m wide strip of soil with the maize plant in the middle). Regarding the control of the weed emerged in the “inter-row” space each working unit of the will be provided with rigid tools (one central foot-goose and two side “L” shaped sweeps). The mechanical treatment will be performed, independently from the weed presence, as hoeing is a very important agronomical practice. On the contrary, broadcast flaming in the inter-row space will be performed after weed detection, using three different LPG pressures and doses according to weed cover (no weed cover-no treatment, weed cover between 0 and 25%-flaming at 0.3 MPa, weed cover higher than 25%-flaming at 0.4 MPa). This very innovative application of precision PWC in maize could represent not only a good opportunity for farmers in term of herbicide use reduction, but also an environmental friendly and energy saving application of flaming in organic farming

The Organizational Client: Attorney-Client Privilege and the No-Contract Rule

A basic issue in the law governing lawyers is the identification of an attorney\u27s client. Various duties, obligations, and rights arise from the attorney-client relationship. In the case of the individual who is a client, the answer is relatively easy. But in the case of the organizational client, the issue becomes more complex and the answers still are evolving. Indeed, the answer may differ depending on the legal context in which the question is asked and on the individual values being served

Fleets of robots for environmentally-safe pest control in agriculture

Feeding the growing global population requires an annual increase in food production. This requirement suggests an increase in the use of pesticides, which represents an unsustainable chemical load for the environment. To reduce pesticide input and preserve the environment while maintaining the necessary level of food production, the efficiency of relevant processes must be drastically improved. Within this context, this research strived to design, develop, test and assess a new generation of automatic and robotic systems for effective weed and pest control aimed at diminishing the use of agricultural chemical inputs, increasing crop quality and improving the health and safety of production operators. To achieve this overall objective, a fleet of heterogeneous ground and aerial robots was developed and equipped with innovative sensors, enhanced end-effectors and improved decision control algorithms to cover a large variety of agricultural situations. This article describes the scientific and technical objectives, challenges and outcomes achieved in three common crops

Experimental studies of turbulent flames at gas turbine relevant burners and operating conditions

With the increasing demand of using alternative and renewable fuels, it becomes of vital importance to consider the fuel flexibility when designing a new burner for gas turbines. Hydrogen-enriched fuel and ammonia are two of these potential fuels, and they can significantly change the operability range of the gas turbines. Thus, it is necessary to enhance both the fundamental understanding on turbulent combustion of these fuels and their combustion performance in practical combustors. Due to its advantages of in-situ measurement, non-intrusiveness and high spatial and temporal resolution, laser-based diagnostics technology has been regarded as one of the best measurement methods for researching combustion processes and phenomena. In this thesis work, experimental studies have been conducted to investigate the turbulent flames of different fuels at various gas turbine related burners, employing laser diagnostics measurement. The measurement methods include planar laser-induced fluorescence (PLIF) for various species, particle image velocimetry (PIV), laser doppler anemometry (LDA), etc.A newly designed gas turbine model combustor had been developed at the Swedish National Centre of Combustion and Technology, so it was named the CECOST burner. One of the main objectives of this thesis is to improve the premixing effect of the CECOST burner by changing part of its internal configuration and investigate its fuel flexibility by using natural gas and hydrogen-enriched methane mixtures as fuels. The experiment was conducted at an atmospheric rig, and high-speed OH* chemiluminescence imaging, simultaneous OH-/CH2O PLIF, and PIV were employed. The operability range and flame structures were investigated for different fuels at various Reynolds numbers (Re). The operability range was found to be highly sensitive to Re, as well as the fuel. For natural gas/air flames, the lean blowout (LBO) limit was approximately independent of Re, while flashback showed obvious dependence on Re and no flashback was observed for higher Re. For hydrogen-enriched methane/air flames, a comparison of combustion characteristics between pure methane and hydrogen-enriched methane with two mixing ratios, 25% and 50% in volume, was investigated. It was found that the flame stabilized in an M shape for all pure methane/air flames, whereas the flame shape transits to a П shape at a specific equivalence ratio ("ϕ" ) for hydrogen-enriched methane flames. Besides, the flashback events with two different mechanisms, combustion-induced vortex breakdown (CIVB) and boundary-layer flashback, were observed. By statistical analysis, we can get that the CIVB flashback took place only for pure methane flames with M shape, while the boundary-layer flashback happened for all hydrogen-enriched flames with П shape.Aiming to achieve stable combustion in lean conditions, a plasma-assisted flame control system is a potential way to help stabilize the flame. An industrial gas turbine combustor, known as Siemens dry low emission (DLE) burner, was modified to place a high-voltage electrode in the rich-pilot-lean (RPL) section and was used for investigation of a rotating gliding arc (RGA) discharge effect on swirl flames stabilized in the gas turbine combustor. In the unmodified DLE burner configuration, fuel and air are injected into the RPL to hold a premixed flame which can help stabilizing the main flame, but in the modified configuration, only air/O2 was injected into the RPL. The flame emissions were measured by a gas sampling probe and emission analyzer. The CO emission results were used to identify the improvement of the LBO limit with plasma assistance. NOx emissions were slightly increased by the RGA plasma, but still, less than the same main flame with RPL flame assisted. Flame emission spectra were also measured. Ammonia combustion is recently one of the hot research topics due to its promising future of carbon-free emission. To deepen our knowledge on turbulent ammonia flames, a jet burner with a large scale was constructed and used to investigate the flame structure of premixed ammonia/air flames, by employing simultaneous OH-/NH-PLIF and LDA measurements. Most of the studied flames are located in the regime of the distributed reaction zone (DRZ), determined by their Karlovitz numbers that are larger than 100. Results of simultaneous OH-/NH-PLIF show that the NH and OH layer can coexist in a thin boundary and the NH signal appears evolving to the reactants side. In addition, the practical gas turbine combustors are all operated at elevated pressure conditions, but it is not easy to perform an experiment at elevated pressure in the lab. A co-axial jet burner was installed and studied in the high-pressure combustion rig (HPCR) at Lund University to investigate the characteristics of methane/air inverse diffusion flames (IDF) at elevated pressure (up to 5 bar). The flame structure and its lift-off height influenced by pressure increasing were discussed. More wrinkles and larger curvature of the flame front were found in the inner flame structure at higher pressure