Regional Integration in the Americas: State of Play, Lessons, and Ways Forward

The Americas have been a key driver of regional trade agreements (RTAs) since the 1990s. This study considers the effect of these agreements on trade liberalization, and the lessons that this offers for other parts of the world, notably Asia. It finds broad geographical coverage of RTAs in the Americas, and evidence that these agreements have broadened and deepened liberalization. It stresses the importance of looking beyond tariffs on goods, to consider liberalization of services and removal of non-tariff barriers, both for academics assessing the true extent of liberalization, and for policymakers looking to ensure well-functioning RTAs. It suggests that RTAs can encourage broader liberalization in Asia, but some sectors will be resistant to liberalization. Moreover, efforts must be made to harmonize the provisions of RTAs, to avoid costly multiplication of rules and to ensure a web of bilateral deals does not undermine multilateral trade.regional trade agreements; trade liberalization; liberalization of services; non-tariff barriers; multilateral trade agreements; bilateral trade agreements

Novel muon imaging techniques

Owing to the high penetrating power of high-energy cosmic ray muons, muon imaging techniques can be used to image large bulky objects, especially objects with heavy shielding. Muon imaging systems work just like CT scanners in the medical imaging field—that is, they can reveal information inside of a target. There are two forms of muon imaging techniques: muon absorption imaging and muon multiple scattering imaging. The former is based on the flux attenuation of muons, and the latter is based on the multiple scattering of muons in matter. The muon absorption imaging technique is capable of imaging very large objects such as volcanoes and large buildings, and also smaller objects like spent fuel casks; the muon multiple scattering imaging technique is best suited to inspect smaller objects such as nuclear waste containers. Muon imaging techniques can be applied in a broad variety of fields, i.e. from measuring the magma thickness of volcanoes to searching for secret cavities in pyramids, and from monitoring the borders of countries checking for special nuclear materials to monitoring the spent fuel casks for nuclear safeguards applications. In this paper, the principles of muon imaging are reviewed. Image reconstruction algorithms such as Filtered Back Projection and Maximum Likelihood Expectation Maximization are discussed. The capability of muon imaging techniques is demonstrated through a Geant4 simulation study for imaging a nuclear spent fuel cask

Controller Area Network Based Distributed Control for Autonomous Vehicles

The goal of this project was to evaluate the potential of a controller area network (CAN bus) to be used as the communication network for a distributed control system on an autonomous agricultural vehicle. The prototype system utilized microcontroller-driven nodes to act as control points along a CAN bus. Messages were transferred to the steering, transmission, and hitch control nodes via a task computer. The task computer utilized global positioning system data to generate appropriate control commands. Laboratory and field testing demonstrated that each of the control nodes could function simultaneously over the CAN bus. Results showed that the task computer adequately applied a feedback control model to the system and achieved guidance accuracy levels well within the desired range. Testing also demonstrated the system’s ability to complete normal field operations, such as headland turning and implement control

Proper Implementation of Precision Agricultural Technologies for Conducting On-Farm Research

Precision agricultural technologies have provided farmers, practitioners and researchers the ability to conduct on-farm or field scale research to refine farm management, improve long term crop production decisions, and implement site-specific management strategies. The limitations of these technologies must be understood by those using them to conduct field scale research to gain useful knowledge from such investigations. Therefore, this paper will address how several precision agriculture technologies can be successfully used to conduct research at a field scale level. Discussions will include yield monitors, variable-rate, auto-swath technologies, guidance systems and GPS/GNSS correction services along with proper setup of machinery equipped with these technologies. The importance of selection, calibration, maintenance, and management will be covered and how these can impact results and thereby decisions made from utilizing these technologies for research purposes. Users must understand the limitations of these technologies. Performance expectations that exceed systematic capabilities may produce research data that are dubious at best. Understanding the limitations of precision agriculture technologies will provide useful knowledge for proper setup and analyses of investigations

Field emission from single-, double-, and multi-walled carbon nanotubes chemically attached to silicon

The chemical attachment and field emission (FE) properties of single-walled carbon nanotubes (SWCNTs), double-walled carbon nanotubes (DWCNTs), and multi-walled carbon nanotubes (MWCNTs) chemically attached to a silicon substrate have been investigated. A high density of CNTs was revealed by atomic force microscopy imaging with orientation varying with CNT type. Raman spectroscopy was used to confirm the CNT type and diameter on the surfaces. The field emission properties of the surfaces were studied and both current-voltage and Fowler-Nordheim plots were obtained. The SWCNTs exhibited superior FE characteristics with a turn-on voltage (Eto) of 1.28 V μm−1 and electric field enhancement factor (β) of 5587. The DWCNT surface showed an Eto of 1.91 V μm−1 and a β of 4748, whereas the MWCNT surface exhibited an Eto of 2.79 V μm−1 and a β of 3069. The emission stability of each CNT type was investigated and it was found that SWCNTs produced the most stable emission. The differences between the FE characteristics and stability are explained in terms of the CNT diameter, vertical alignment, and crystallinity. The findings suggest that strength of substrate adhesion and CNT crystallinity play a major role in FE stability. Comparisons to other FE studies are made and the potential for device application is discussed

Rate Response Assessment from Various Granular VRT Applicators

Variable-rate technology (VRT) adds complexity to application equipment, thereby confounding the assessment of applicator performance. The intent of this investigation was to assess the rate response of various VRT granular applicators: two spinner spreaders (A and B), and two pneumatic applicators (C and D). Variable-rate (VR) tests were conducted to quantify the rate response characteristics (delay and transition times) for the applicators. A sigmoidal function was used to model the rate response for five of the six tests. Applicator A exhibited a linear response during decreasing rate changes. Results indicated that only applicator B demonstrated consistent delay and transition times, enabling the use of a single “look-ahead” time for rate response time correction. Contouring of prescription maps increased the transition times for applicator D by enlarging the adjustment area between management zones. Rate changes were quicker for the two newer VR control systems, signifying advancement in hydraulic control valve technology. This research illustrates the need for standard testing protocols for VRT systems to help guide VRT software developers, equipment manufacturers, and end users

Seed Tape Effects on Corn Emergence under Greenhouse Conditions

Seed tape has recently received attention as an alternative planting system for smallholder farmers in underdeveloped regions of South America, Africa, China, and India (Mateus, 2014). Seed companies are also developing seed-tape planting systems for germplasm evaluations (Deppermann et al., 2013). Although seed tape has been promoted as a method for ensuring uniform seed spacing and plant density of small-seeded flowers, herbs, and vegetables (Chancellor, 1969), little or no information is available on the use of seed tape for larger-seeded row crops and its effect on crop emergence. The objective of this study was to compare the emergence of corn seed embedded in tape to seeds planted by hand and to determine seed tape effects on rate of corn emergence

Source Mechanism of Small Long-Period Events at Mount St. Helens in July 2005 Using Template Matching, Phase-Weighted Stacking, and Full-Waveform Inversion

Long-period (LP, 0.5-5 Hz) seismicity, observed at volcanoes worldwide, is a recognized signature of unrest and eruption. Cyclic LP “drumbeating” was the characteristic seismicity accompanying the sustained dome-building phase of the 2004–2008 eruption of Mount St. Helens (MSH), WA. However, together with the LP drumbeating was a near-continuous, randomly occurring series of tiny LP seismic events (LP “subevents”), which may hold important additional information on the mechanism of seismogenesis at restless volcanoes. We employ template matching, phase-weighted stacking, and full-waveform inversion to image the source mechanism of one multiplet of these LP subevents at MSH in July 2005. The signal-to-noise ratios of the individual events are too low to produce reliable waveform inversion results, but the events are repetitive and can be stacked. We apply network-based template matching to 8 days of continuous velocity waveform data from 29 June to 7 July 2005 using a master event to detect 822 network triggers. We stack waveforms for 359 high-quality triggers at each station and component, using a combination of linear and phase-weighted stacking to produce clean stacks for use in waveform inversion. The derived source mechanism points to the volumetric oscillation (∼10 m3) of a subhorizontal crack located at shallow depth (∼30 m) in an area to the south of Crater Glacier in the southern portion of the breached MSH crater. A possible excitation mechanism is the sudden condensation of metastable steam from a shallow pressurized hydrothermal system as it encounters cool meteoric water in the outer parts of the edifice, perhaps supplied from snow melt