SPECIFICATIONS OF A PROTOTYPE SOFTWARE SYSTEM FOR DEVELOPING VARIABLE-RATE TREATMENT PRESCRIPTIONS FOR USE IN PRECISION AGRICULTURE

This paper discusses the process of developing variable-rate treatment prescriptions and gives specifications for a prototype software system for implementing that process. The process is based on statistical analysis of data from embedded field trials, and incorporates producer preferences in determining a treatment prescription. The system can be used by researchers in agricultural research stations for developing prescriptions for commercial agricultural producers. The specifications provided are general enough to be implemented using a variety of statistical and database packages that are available to researchers. In addition to these specifications we provide online access to source code for implementing the system in SAS. We use this system to develop treatment prescriptions for a commercial cotton farming operation in northeast Louisiana. The prescriptions are based on data from a precision agriculture experiment conducted in 2006. The objective of that study was to compare the effects of five nitrogen rates on cotton lint yield across several soil types for the purpose of developing a variable-rate nitrogen treatment prescription for future use on that farm. Several possible producer preferences were incorporated with the results of the field trial to produce optional treatment prescriptions for the producer

Developments in Performance Monitoring of Concrete Exposed to Extreme Environments.

The performance of the surface zone of concrete is acknowledged as a major factor governing the rate of deterioration of reinforced concrete structures because it provides the only barrier to the ingress of water containing dissolved ionic species such as chlorides, which ultimately initiate corrosion of the reinforcement. In situ monitoring of cover-zone concrete is therefore critical in attempting to make realistic predictions as to the in-service performance of the structure. To this end, this paper presents developments in a remote interrogation system to allow for continuous, real-time monitoring of the cover-zone concrete from an office setting. Use is made of a multi electrode array embedded within cover-zone concrete to acquire discretized electrical resistivity and temperature measurements, with both parameters monitored spatially and temporally. On-site instrumentation, which allows for the remote interrogation of concrete samples placed at a marine exposure site, is detailed together with data handling and processing procedures. Site measurements highlight the influence of temperature on electrical resistivity and an Arrhenius-based temperature correction protocol is developed using on-site measurements to standardize resistivity data to a reference temperature; this is an advancement over the use of laboratory-based procedures. The testing methodology and interrogation system represent a robust, low-cost, and high-value technique that could be deployed for intelligent monitoring of reinforced concrete structures

Investigating situated cultural practices through cross-sectoral digital collaborations: policies, processes, insights

The (Belfast) Good Friday Agreement represents a major milestone in Northern Ireland's recent political history, with complex conditions allowing for formation of a ‘cross-community’ system of government enabling power sharing between parties representing Protestant/loyalist and Catholic/nationalist constituencies. This article examines the apparent flourishing of community-focused digital practices over the subsequent ‘post-conflict’ decade, galvanised by Northern Irish and EU policy initiatives armed with consolidating the peace process. Numerous digital heritage and storytelling projects have been catalysed within programmes aiming to foster social processes, community cohesion and cross-community exchange. The article outlines two projects—‘digital memory boxes’ and ‘interactive galleon’—developed during 2007–2008 within practice-led PhD enquiry conducted in collaboration with the Nerve Centre, a third-sector media education organisation. The article goes on to critically examine the processes involved in practically realising, and creatively and theoretically reconciling, community-engaged digital production in a particular socio-political context of academic-community collaboration

Challenges and opportunities for assessing transport properties of high-performance concrete

In this paper, a review of techniques is given so that both, the challenges and opportunities for assessing transport properties of high-performance concrete, are highlighted. A knowledge of performance of structural concrete is required for design and compliance purposes. One driving force for the use of high performance concretes (HPC) is enhanced durability yet it would be wrong to assume that all HPCs can deliver the desired performance level. In situ characterisation of the permeation properties of concrete is the most viable means for assessing durability and has become increasingly important over the past 20 years. A variety of methods exist that provide a range of parameters, e.g. air permeability, water absorption rate, sorptivity and chloride migration coefficient

Antiferromagnetic real-space configuration probed by x-ray orbital angular momentum phase dichroism

X-ray beams with orbital angular momentum (OAM) are an up-and-coming tool for x-ray characterization techniques. Beams with OAM have an azimuthally varying phase that leads to a gradient of the light field. New material properties can be probed by utilizing the unique phase structure of an OAM beam. Here, we demonstrate a novel type of phase dichroism in resonant diffraction from an artificial antiferromagnet with a topological defect. The scattered OAM beam has circular dichroism whose sign is coupled to the phase of the beam, which reveals the real-space configuration of the antiferromagnetic ground state. Thermal cycling of the artificial antiferromagnet can change the ground state, as indicated by the changing phase dichroism. These results exemplify the potential of OAM beams to probe matter in a way that is inaccessible using typical x-ray techniques

Production of highly-polarized positrons using polarized electrons at MeV energies

The Polarized Electrons for Polarized Positrons experiment at the injector of the Continuous Electron Beam Accelerator Facility has demonstrated for the first time the efficient transfer of polarization from electrons to positrons produced by the polarized bremsstrahlung radiation induced by a polarized electron beam in a high-$Z$ target. Positron polarization up to 82\% have been measured for an initial electron beam momentum of 8.19~MeV/$c$, limited only by the electron beam polarization. This technique extends polarized positron capabilities from GeV to MeV electron beams, and opens access to polarized positron beam physics to a wide community.Comment: 5 pages, 4 figure