154 research outputs found
Mass-Market Receiver for Static Positioning: Tests and Statistical Analyses
Nowadays, there are several low cost GPS receivers able to provide both pseudorange and carrier phase measurements in the L1band, that allow to have good realtime performances in outdoor condition. The present paper describes a set of dedicated tests in order to evaluate the positioning accuracy in static conditions. The quality of the pseudorange and the carrier phase measurements let hope for interesting results. The use of such kind of receiver could be extended to a large number of professional applications, like engineering fields: survey, georeferencing, monitoring, cadastral mapping and cadastral road. In this work, the receivers performance is verified considering a single frequency solution trying to fix the phase ambiguity, when possible. Different solutions are defined: code, float and fix solutions. In order to solve the phase ambiguities different methods are considered. Each test performed is statistically analyzed, highlighting the effects of different factors on precision and accurac
89Y NMR Probe of Zn Induced Local Magnetism in YBa2(Cu(1-y)Zn(y))3O(6+x)
We present detailed data and analysis of the effects of Zn substitution on
the planar Cu site in YBaCuO (YBCO) as evidenced from
our Y NMR measurements on oriented powders. For we find
additional NMR lines which are associated with the Zn substitution. From our
data on the intensities and temperature dependence of the shift, width, and
spin-lattice relaxation rate of these resonances, we conclude that the spinless
Zn 3 state induces local moments on the near-neighbour () Cu
atoms. Additionally, we conjecture that the local moments actually extend to
the farther Cu atoms with the magnetization alternating in sign at subsequent
sites. We show that this analysis is compatible with ESR data taken on
dilute Gd doped (on the Y site) and on neutron scattering data reported
recently on Zn substituted YBCO. For optimally doped compounds
Y resonances are not detected, but a large % -dependent
contribution to the Y NMR linewidth is evidenced and is also attributed
to the occurence of a weak induced local moment near the Zn. These results are
compatible with macroscopic magnetic measurements performed on YBCO
samples prepared specifically in order to minimize the content of impurity
phases. We find significant differences between the present results on the
underdoped YBCO samples and Al NMR data taken on Al
substituted on the Cu site in optimally doped LaCuO. Further
experimental work is needed to clarify the detailed evolution of the impurity
induced magnetism with hole content in the cuprates.Comment: To be published in EPJB 15 pages of text and figures in eps forma
Pesticide application horticultural and floricultural farms of Liguria Region: Current situation and results of one year of sprayer inspections
contribution to session 2 Member States may apply different timetables and inspection intervals with exceptions following a risk assessment and exempt handheld pesticide application equipment or knapsack sprayers (according article 8/3
The evaluation of sprayers inspection procedure in Italy
contribution to session 6
Defining criteria for rejecting pesticide application equipment, authorization and monitoring of worksho
A Comparative Sensitivity Analysis of GPS Receivers
GNSS technologies are progressively becoming one
of the key elements in most of innovative wireless
applications. Most location-based services and
systems are in fact employing standalone GPS,
GPS+EGNOS (or WAAS), Assisted-GPS and
Differential GPS as core technologies and therefore
more and more companies have been integrating
GNSS receivers into their consumer products. By
considering the large number of available GPS
receivers on the market and the lack of standard
specifications on the performance, a general
evaluation of low cost GPS chipset is very
interesting. The present paper describes the
performance tests of a set of GPS receivers by
different manufacturers in different environmental
conditions (outdoor, light indoor, temporary
blockage of the signal). The results of the tests are
compared with the claimed performance reported on
the data sheets.
The comparative study on the performance is
performed according to different figures of merit:
acquisition sensitivity, Time To First Fix (TTFF)
and the accuracy.
Performance of the different receivers were tested
by means of a hardware platform and a software tool
called Sat-Surf and Sat-Surfer respectively
Doppler measurement integration for kinematic real-time GPS positioning
The present paper discusses the advantages of the
use of Doppler shift measurements in a Kalman filter
estimator in order to improve the kinematic stand-alone
global positioning system positioning performance. Tests
conducted in an urban environment using a single-frequency
receiver demonstrate the real advantages of the proposed real-
time computation technique
Normal State Magnetic Properties of Ni and Zn Substituted in YBa_{2}Cu_{3} O_{6+x}: Hole-Doping Dependence
We present SQUID susceptibility data on Zn and Ni substituted
YBa_{2}Cu_{3}O_{6+x}. Cross-checks with NMR yield an unprecedented accuracy in
the estimate of the magnetic susceptibility associated with the substituants,
from the underdoped to the lightly overdoped case. This allows us to determine
the Weiss temperature \theta for YBCO: its value is very small for all hole
dopings n_h. Since in conventional metals, the Kondo temperature,
, magnetic screening effects would not be expected for ; in contrast, increasing n_h produces a reduction of the small moment
induced by Zn^{2+} and a nearly constant effective moment for Ni^{2+}
corresponding to a spin 1/2 rather than to a spin 1.Comment: 4 pages, 5 figures, to be published in Europhysics Letter
Cu NMR evidence for enhanced antiferromagnetic correlations around Zn impurities in YBa2Cu3O6.7
Doping the high-Tc superconductor YBa2Cu3O6.7 with 1.5 % of non-magnetic Zn
impurities in CuO2 planes is shown to produce a considerable broadening of 63Cu
NMR spectra, as well as an increase of low-energy magnetic fluctuations
detected in 63Cu spin-lattice relaxation measurements. A model-independent
analysis demonstrates that these effects are due to the development of
staggered magnetic moments on many Cu sites around each Zn and that the
Zn-induced moment in the bulk susceptibility might be explained by this
staggered magnetization. Several implications of these enhanced
antiferromagnetic correlations are discussed.Comment: 4 pages including 2 figure
The necessity of a harmonized procedure for sprayers inspectors training: the Italian activity
European Directive on Sustainable Use of Pesticides requires that the people making inspections of sprayers in use have an official license, recognized at national level, released by the competent Authority. In Italy, Authorities responsible of training and upgrading of sprayers inspectors are Regional and Provincial administrations. They make this job in collaboration with research institutes that provide qualified teachers.With the aim to homogenize in the whole country the activity of training and licensing of sprayers inspectors the rules for training courses and the criteria for releasing licenses have been defined by ENAMA. Training courses shall have a duration of at least 40 hours subdivided between theory (60% of total time) and practical (40% of total time).Topics treated during courses are: criteria to apply pesticides, main sprayer types used in agriculture and relative components, test methods and equipment used to carry out the inspections of sprayers in use and to adjust them. The exam to get the inspector license shall consist in: a) filling of a questionnaire with multiple answers (at least 80% of answers have to be correct); the questions are selected among a database approved by ENAMA Working Group; b) oral test; c) practical exam consisting in the complete inspection of one sprayer.In order to guarantee the same quality level of sprayers inspections in the different European countries and to guarantee the mutual recognition of inspections made it is considered necessary to reach in short terms an agreement to harmonize the activity of training, licensing and upgrading of sprayers inspectors across Europe
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