4,839 research outputs found
Design of a horizontal neutron reflectometer for the European Spallation Source
A design study of a horizontal neutron reflectometer adapted to the general
baseline of the long pulse European Spallation Source (ESS) is presented. The
instrument layout comprises solutions for the neutron guide, high-resolution
pulse shaping and beam bending onto a sample surface being so far unique in the
field of reflectometry. The length of this instrument is roughly 55 m, enabling
resolutions from 0.5% to 10%. The incident beam is
focussed in horizontal plane to boost measurements of sample sizes of 1*1
cm{^2} and smaller with potential beam deflection in both downward and upward
direction. The range of neutron wavelengths untilized by the instrument is 2 to
7.1 (12.2, ...) {\AA}, if every (second, ...) neutron source ulse is used.
Angles of incidence can be set between 0{\deg} and 9{\deg} with a total
accessible q-range from 4*10^{-3} {\AA}^{-1} up to 1 {\AA}^{-1}. The instrument
operates both in {\theta}/{\theta} (free liquid surfaces) and
{\theta}/2{\theta} (solid/liquid, air/solid interfaces) geometry. The
experimental setup will in particular enable direct studies on ultrathin films
(d ~ 10 {\AA}) and buried monolayers to multilayered structures of up to 3000
{\AA} total thickness. The horizontal reflectometer will further foster
investigations of hierarchical systems from nanometer to micrometer length
scale, as well as their kinetics and dynamical properties, in particular under
load (shear, pressure, external fields). Polarization and polarization analysis
as well as the GISANS option are designed as potential modules to be
implemented separately in the generic instrument layout. The instrument is
highly flexible and offers a variety of different measurement modes. With
respect to its mechanical components the instrument is exclusively based on
current technology. Risks of failure for the chosen setup are minimum.Comment: Matched to the version submitted to Nuclear Instruments and Methods
An analysis method for time ordered data processing of Dark Matter experiments
The analysis of the time ordered data of Dark Matter experiments is becoming
more and more challenging with the increase of sensitivity in the ongoing and
forthcoming projects. Combined with the well-known level of background events,
this leads to a rather high level of pile-up in the data. Ionization,
scintillation as well as bolometric signals present common features in their
acquisition timeline: low frequency baselines, random gaussian noise, parasitic
noise and signal characterized by well-defined peaks. In particular, in the
case of long-lasting signals such as bolometric ones, the pile-up of events may
lead to an inaccurate reconstruction of the physical signal (misidentification
as well as fake events). We present a general method to detect and extract
signals in noisy data with a high pile-up rate and qe show that events from few
keV to hundreds of keV can be reconstructed in time ordered data presenting a
high pile-up rate. This method is based on an iterative detection and fitting
procedure combined with prior wavelet-based denoising of the data and baseline
subtraction. {We have tested this method on simulated data of the MACHe3
prototype experiment and shown that the iterative fitting procedure allows us
to recover the lowest energy events, of the order of a few keV, in the presence
of background signals from a few to hundreds of keV. Finally we applied this
method to the recent MACHe3 data to successfully measure the spectrum of
conversion electrons from Co57 source and also the spectrum of the background
cosmic muons
Reflexion M\"ossbauer analysis of the in situ oxidation products hydroxycarbonate green rust
The purpose of this study is to determine the nature of the oxidation
products of FeII-III hydroxycarbonate FeII4FeIII2(OH)12CO3~3H2O (green rust
GR(CO32-)) by using the miniaturised M\"ossbauer spectrometer MIMOS II. Two
M\"ossbauer measurements methods are used: method (i) with green rust pastes
coated with glycerol and spread into Plexiglas sample holders, and method (ii)
with green rust pastes in the same sample holders but introduced into a
gas-tight cell with a beryllium window under a continuous nitrogen flow. Method
(ii) allows us to follow the continuous deprotonation of GR(CO32-) into the
fully ferric deprotonated form FeIII6O4(OH)8CO3~3H2O by adding the correct
amount of H2O2, without any further oxidation or degradation of the samples
Embodied Artificial Intelligence through Distributed Adaptive Control: An Integrated Framework
In this paper, we argue that the future of Artificial Intelligence research
resides in two keywords: integration and embodiment. We support this claim by
analyzing the recent advances of the field. Regarding integration, we note that
the most impactful recent contributions have been made possible through the
integration of recent Machine Learning methods (based in particular on Deep
Learning and Recurrent Neural Networks) with more traditional ones (e.g.
Monte-Carlo tree search, goal babbling exploration or addressable memory
systems). Regarding embodiment, we note that the traditional benchmark tasks
(e.g. visual classification or board games) are becoming obsolete as
state-of-the-art learning algorithms approach or even surpass human performance
in most of them, having recently encouraged the development of first-person 3D
game platforms embedding realistic physics. Building upon this analysis, we
first propose an embodied cognitive architecture integrating heterogenous
sub-fields of Artificial Intelligence into a unified framework. We demonstrate
the utility of our approach by showing how major contributions of the field can
be expressed within the proposed framework. We then claim that benchmarking
environments need to reproduce ecologically-valid conditions for bootstrapping
the acquisition of increasingly complex cognitive skills through the concept of
a cognitive arms race between embodied agents.Comment: Updated version of the paper accepted to the ICDL-Epirob 2017
conference (Lisbon, Portugal
Economics of mixed farming under rotational grazing with low input system
Non-Peer ReviewedThis study was conducted at the Manitoba Zero Tillage Research Farm (MZTRA) located 17.6 kilometres north of Brandon, Manitoba. The objective was to evaluate new farming systems designed to improve economic return, sequester carbon, and reduce inputs, energy use, and greenhouse gas emissions of mixed production systems. Yield and net revenue varied across MZTRA landscapes due to spatial and temporal variability of soil fertility and biophysical properties. Relative to studies with conservation tillage in the Canadian Prairies, producers can expect to achieve higher crop yields with most crops under zero tillage. Compared to crop yields reported for conventional tillage (CT) in Thin Black soil zone of Saskatchewan, spring wheat was 11 to 32% higher, winter wheat 41 to 66% higher, pea 27% higher, and flax was comparable. There were no significant differences in total input cost among annual crop rotation. Our results indicated that small-scale mixed crop and livestock operations had higher operating costs, the success of which depended on animal and environmental conditions as well as management. Hay and grazing systems also had higher risk. Among annual crops, although net revenue was higher for canola and peas, risk was also higher due to higher net revenue variation for these two crops. The findings showed that the use of zero tillage with low inputs has the potential to save energy use and improve energy use efficiency. The use of zero tillage provided significant energy savings (compared to CT reported by Zentner et al. (2004)) in on-farm use of fuel and in machine operation and manufacture. The ratio of grain, oilseed and pea yield to emission of CO2 (kg yield per kg CO2 emitted) varied considerably between crops. This ratio was similar for winter wheat and spring wheat, but not for canola and flax. Canola ratios were higher than flax (2.03 compare to 1.92 kg of flax). Peas had a higher ratio (8.47 kg), due to low fertilizer rates. Alfalfa had the highest ratio (17.8 kg yield kg CO2, due to low inputs of fertilizer and pesticides. Overall the crops and rotations studied were highly energy efficient and reduced the calculated contribution of GHGs to the environment especially when legume and N-fixing crops were incorporated
Articulations between commercial banks and microfinance institutions in Sub-Saharan Africa: the case of Cameroon
In this article, we evaluate, from the point of view of banks, the potential of articulations between commercial banks and microfinance institutions (MFIs) in Cameroun in terms of financing of the rural and the micro, small and medium enterprises (MSMEs). Furthermore, we seek to define the best form of partnership between the two types of institutions. The results obtained suggest that the articulations between banks and MFIs can potentially be beneficial to all stakeholders (banks, MFIs but also recipients). This study also highlights the fact that these articulations can be even more beneficial if national commercial banks, under the Cameroonian law in our case, participate rather than branches of foreign banking groups. Indeed, our research reveals that through these partnerships, from their cultural proximity and their propensity to take more risks, national commercial banks will more likely offer either directly or indirectly (through MFIs) more adapted financial products and services to both the rural and the MSMEs’ segments. The question of knowing if a better form of partnership between commercial banks and MFIs exists, results suggest that there is no better form of partnership as such; that the best form depends on the MFI’s development stage and that in any case this partnership should privilege a national commercial bank rather than a branch of a foreign bank. Even if the foreign banks’ contest might be necessary at a given stage of the process, the results make it also possible to consider a new model of interactions implying Microfinance investment vehicles and national commercial banks. This model would have the advantage to help mitigate risks that those vehicles perceive when deciding to directly invest in MFIs.Banks, Microfinance institutions, Microfinance investment vehicles, Sub-Saharan Africa, Cameroon
Modelling soil dynamics and the effect of nitrogen levels on potato yield function
Non-Peer ReviewedCrop yield is maximized when optimal levels of nutrients, water, and other inputs are available to the crop and the influence of disease and weeds has been minimized. While each crop has differing responses to nutrient availability, modelling soil dynamics and the effect of nitrogen levels on potato yield is very important. The objective of this study was to model several environmental components of potato yield function including soil characteristics and organic matter content, soil nitrogen, temperature component, moisture component, solum and nitrogen mineralization, nitrogen fertilizer, and nitrogen sufficiency. The interaction of these components
with moisture availability and nitrogen sufficiency was shown to impact potato yield
Spatial and statistical variability of soil properties for fields in BMPs in the Steppler sub-watershed, South Tobacco Creek Watershed, research design and preliminary results
Non-Peer Reviewe
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