Economics of autonomous equipment for arable farms

By collecting more data at a higher resolution and by creating the capacity to implement detailed crop management, autonomous crop equipment has the potential to revolutionise precision agriculture (PA), but unless farmers find autonomous equipment profitable it is unlikely to be widely adopted. The objective of this study was to identify the potential economic implications of autonomous crop equipment for arable agriculture using a grain-oilseed farm in the United Kingdom as an example. The study is possible because the Hands Free Hectare (HFH) demonstration project at Harper Adams University has produced grain with autonomous equipment since 2017. That practical experience showed the technical feasibility of autonomous grain production and provides parameters for farm-level linear programming (LP) to estimate farm management opportunities when autonomous equipment is available. The study shows that arable crop production with autonomous equipment is technically and economically feasible, allowing medium size farms to approach minimum per unit production cost levels. The ability to achieve minimum production costs at relatively modest farm size means that the pressure to “get big or get out” will diminish. Costs of production that are internationally competitive will mean reduced need for government subsidies and greater independence for farmers. The ability of autonomous equipment to achieve minimum production costs even on small, irregularly shaped fields will improve environmental performance of crop agriculture by reducing pressure to remove hedges, fell infield trees and enlarge fields

The impact of swarm robotics on arable farm size and structure in the UK

Swarm robotics has the potential to radically change the economies of size in agriculture and this will impact farm size and structure in the UK. This study uses a systematic review of the economics of agricultural robotics literature, data from the Hands Free Hectare (HFH) demonstration project which showed the technical feasibility of robotic grain production, and farm-level linear programming (LP) to estimate changes in the average cost curve for wheat and oilseed rape from swarm robotics. The study shows that robotic grain production is technically and economically feasible. A preliminary analysis suggests that robotic production allows medium size farms to approach minimum per unit production cost levels and that the UK costs of production can compete with imported grain. The ability to achieve minimum production costs at relatively small farm size means that the pressure to “get big or get out” will diminish. Costs of production that are internationally competitive will mean reduced need for government subsidies and greater independence for farmers. The ability of swarm robotics to achieve minimum production costs even on small, irregularly shaped fields will reduce pressure to tear out hedges, cut infield trees and enlarge fields

AGB yields and Galactic Chemical Evolution : last updated

We study the s-process abundances at the epoch of the Solar-system formation as the outcome of nucleosynthesis occurring in AGB stars of various masses and metallicities. The calculations have been performed with the Galactic chemical evolution (GCE) model presented by [1, 2]. With respect to previous works, we used updated solar meteoritic abundances, a neutron capture cross section network that includes the most recent measurements, and we implemented the s-process yields with an extended range of AGB initial masses. The new set of AGB yields includes a new evaluation of the $^{22}$Ne(α, n)$^{25}$Mg rate, which takes into account the most recent experimental information

An economic appraisal of the effect of tire inflation pressure for alternative tillage systems on a silty clay loam soil

Compacting soil has an adverse effect on soil properties, decreases crop productivity, and subsequently reduces farm income. Low tire inflation pressure (LTP) help in managing soil compaction and protecting the soil environment; however, there is scant economic data available on LTP in US Midwest farming systems. Hence, a 3-year study investigated the effects of LTP, compared to tires inflated to the standard tire inflation pressure systems, on crop yield and farm economy for a typical maize/soybean rotation. The effect of the two tire inflation pressure systems was factorialized with three tillage systems: deep tillage (DT, 450 mm), shallow tillage (ST, 100 mm), and no-till systems. The results showed that LTP systems increased maize (Zea mays) yield by 4.51% (2017) and 2.70% (2018) and soybean (Glycine max) by 3.70% in 2018. Annual earnings for both 200- and 800-ha farms increased for all tillage systems with LTP tires based on a partial budget analysis. The payback periods for LTP tires were very short, ranging from 0.32 years for DT on an 800-ha farm to 1.18 years for ST on a 200-ha farm. The net present value of the higher returns with LTP tires was substantial, especially for the DT system. This study shows a strong economic benefit from investments in LTP tires on silty clay loam soils in the US Midwest

Low energy scattering cross section ratios of N 14 (p,p) N 14

Background: The slowest reaction in the first CNO cycle is N14(p,γ)O15, therefore its rate determines the overall energy production efficiency of the entire cycle. The cross section presents several strong resonance contributions, especially for the ground-state transition. Some of the properties of the corresponding levels in the O15 compound nucleus remain uncertain, which affects the uncertainty in extrapolating the capture cross section to the low energy range of astrophysical interest. Purpose: The N14(p,γ)O15 cross section can be described by using the phenomenological R matrix. Over the energy range of interest, only the proton and γ-ray channels are open. Since resonance capture makes significant contributions to the N14(p,γ)O15 cross section, resonant proton scattering data can be used to provide additional constraints on the R-matrix fit of the capture data. Methods: A 4 MV KN Van de Graaff accelerator was used to bombard protons onto a windowless gas target containing enriched N14 gas over the proton energy range from Ep=1.0 to 3.0 MeV. Scattered protons were detected at θlab=90, 120°, 135°, 150°, and 160° using ruggedized silicon detectors. In addition, a 10 MV FN Tandem Van de Graaff accelerator was used to accelerate protons onto a solid Adenine (C5H5N5) target, of natural isotopic abundance, evaporated onto a thin self-supporting carbon backing, over the energy range from Ep=1.8 to 4.0 MeV. Scattered protons were detected at 28 angles between θlab=30.4° and 167.7° by using silicon photodiode detectors. Results: Relative cross sections were extracted from both measurements. While the relative cross sections do not provide as much constraint as absolute measurements, they greatly reduce the dependence of the data on otherwise significant systematic uncertainties, which are more difficult to quantify. The data are fit simultaneously using an R-matrix analysis and level energies and proton widths are extracted. Even with relative measurements, the statistics and large angular coverage of the measurements result in more confident values for the energies and proton widths of several levels; in particular, the broad resonance at Ec.m.=2.21 MeV, which corresponds to the 3/2+ level at Ex=9.51 MeV in O15. In particular, the s- and d-wave angular-momentum channels are separated. Conclusion: The relative cross sections provide a consistent set of data that can be used to better constrain a full multichannel R-matrix extrapolation of the capture data. It has been demonstrated how the scattering data reduce the uncertainty through a preliminary Monte Carlo uncertainty analysis, but several other issues remain that make large contributions to the uncertainty, which must be addressed by further capture and lifetime measurements

First direct measurement of 12C (12C,n) 23Mg at stellar energies

© 2016 Owned by the authors, published by EDP Sciences. Neutrons produced by the carbon fusion reaction12C(12C,n)23Mg play an important role in stellar nucleosynthesis. Past studies have shown large discrepancies between experimental data and theory, leading to an uncertain cross section extrapolation at astrophysical energies. We present the first direct measurement which extends deep into the astrophysical energy range along with a new and improved extrapolation technique based on experimental data from the mirror reaction12C(12C,p)23Na. The new reaction rate has been determined with a well-defined uncertainty which exceeds the precision required by astrophysics models. Using our constrained rate, we find that12C(12C,n)23Mg is crucial to the production of Na and Al in Pop-III Pair Instability Supernovae

Experimental investigation of the 12C+12C fusion at very low energies by direct and indirect methods

The 12C+12C fusion reaction plays a crucial role during stellar evolution. The astrophysically important energy range spans from 1 MeV to 3 MeV. However, its cross section has not been determined with enough precision, despite numerous studies, due to the extremely low reaction cross sections and the large experimental background. To allow measurements of the 12C+12C fusion at astrophysical energies, we developed an efficient thick-target method using large-area silicon strip detectors. Further measurements at even lower energies will be performed using coincidences between a silicon-detector and a Ge-detector array, at the high-current accelerator under construction at the University of Notre Dame. Since the coincidence method does not allow obtaining information about the channels without gamma-ray emission, a solenoid spectrometer has been constructed for complementary measurements. Meanwhile, we are also investigating the 24Mg(α, α') reaction using the Grand Raiden Spectrometer at RCNP to search for potential resonances in the 12C+12C fusion reaction. Preliminary results from these measurements will be presented

Cross section of the reaction 18O(p,γ)19F at astrophysical energies: The 90 keV resonance and the direct capture component

The observation of oxygen isotopes in giant stars sheds light on mixing processes operating in their interiors. Due to the very strong correlation between nuclear burning and mixing processes it is very important to reduce the uncertainty on the cross sections of the nuclear reactions that are involved. In this paper we focus our attention on the reaction 18O(p, γ)19F. While the 18O(p, α)15Nchannel is thought to be dominant, the (p,γ) channel can still be an important component in stellar burning in giants, depending on the low energy cross section. So far only extrapolations from higher-energ