Smarter irrigation scheduling in the sugarcane farming system using the Internet of Things

Better irrigation practices can lead to improved yields through less water stress and reduced water usage to deliver economic benefits for farmers. More and more sugarcane growers are transitioning to automated irrigation in the Burdekin and other regions. Automated irrigation systems can save farmers a significant amount of time by remotely turning on and off pumps and valves. However, the system could be improved if it could be integrated with tools that factor in the weather, crop growing conditions, water deficit, and crop stress, to improve irrigation use efficiency. IrrigWeb is a decision-support tool that is turned to as a solution to this problem. IrrigWeb uses CANEGRO to help farmers decide when to irrigate and how much to apply. Farmers can then use this information to plan their irrigation management. However, managing irrigation is a considerable time investment for Burdekin farmers. A tool is needed to integrate the auto-irrigation system (e.g., WiSA) and IrrigWeb to provide a smarter irrigation solution. An uplink program (WiSA to IrrigWeb) has been successfully developed and implemented as part of a pilot study. It saves farmers a significant amount of time by uploading irrigation and rainfall data automatically instead of the farmer having to input them manually. This paper focuses on developing a smarter irrigation-scheduling tool that connects IrrigWeb to WiSA. A downlink program was developed to download, calculate and apply irrigation schedules automatically. In this process, sugarcane irrigators will spend less time manually setting up irrigation schedules as it will happen automatically. The simulation results demonstrated that the downlink program could improve the scheduling by incorporating practical limitations, such as pumping capacity or pumping time constraints, that are found on the farm

Flux-rope twist in eruptive flares and CMEs : due to zipper and main-phase reconnection

Funding: UK Science and Technology Facilities CouncilThe nature of three-dimensional reconnection when a twisted flux tube erupts during an eruptive flare or coronal mass ejection is considered. The reconnection has two phases: first of all, 3D “zipper reconnection” propagates along the initial coronal arcade, parallel to the polarity inversion line (PIL); then subsequent quasi-2D “main phase reconnection” in the low corona around a flux rope during its eruption produces coronal loops and chromospheric ribbons that propagate away from the PIL in a direction normal to it. One scenario starts with a sheared arcade: the zipper reconnection creates a twisted flux rope of roughly one turn (2π radians of twist), and then main phase reconnection builds up the bulk of the erupting flux rope with a relatively uniform twist of a few turns. A second scenario starts with a pre-existing flux rope under the arcade. Here the zipper phase can create a core with many turns that depend on the ratio of the magnetic fluxes in the newly formed flare ribbons and the new flux rope. Main phase reconnection then adds a layer of roughly uniform twist to the twisted central core. Both phases and scenarios are modeled in a simple way that assumes the initial magnetic flux is fragmented along the PIL. The model uses conservation of magnetic helicity and flux, together with equipartition of magnetic helicity, to deduce the twist of the erupting flux rope in terms the geometry of the initial configuration. Interplanetary observations show some flux ropes have a fairly uniform twist, which could be produced when the zipper phase and any pre-existing flux rope possess small or moderate twist (up to one or two turns). Other interplanetary flux ropes have highly twisted cores (up to five turns), which could be produced when there is a pre-existing flux rope and an active zipper phase that creates substantial extra twist.PostprintPublisher PDFPeer reviewe

Focused ion beam and field-emission microscopy of metallic filaments in memory devices based on thin films of an ambipolar organic compound consisting of oxadiazole, carbazole and fluorene units

We report on the mechanism of operation of organic thin film resistive memory architectures based on an ambipolar compound consisting of oxadiazole, carbazole, and fluorene units. Cross-sections of the devices have been imaged by electron microscopy both before and after applying a voltage. The micrographs reveal the growth of filaments, with diameters of 50 nm–100 nm, on the metal cathode. We suggest that these are formed by the drift of aluminium ions from the anode and are responsible for the observed switching and negative differential resistance phenomena in the memory devices