266 research outputs found
Concentrations of CO₂ from composting under different treatments
Received: January 28th, 2021 ; Accepted: July 7th, 2021 ; Published: July 21st, 2021 ; Correspondence: [email protected] aim of this study was to analyse the production of CO2 concentrations in relation
to the composting technology used. Three loose piles of bio-waste (V1, V2, V3) were created
with the same volume. V1 reference pile was without any treatment. The biological preparation
containing probiotic bacteria was added to the pile V2. The pile V3 was treated once a week by
turning and watering. The degassing shafts were installed in each pile and the Multigas Monitor
1312 gas analyser with the Multipoint Sampler 1309 were used to measure of gas concentrations
during the degradation process. Continuous 24-hour measurements of carbon dioxide
concentrations from each pile were performed in the first, fourth, and seventh week of the
degradation process to compare the amount of concentrations between piles in those weeks. At
the beginning of the process, there were no significant differences in the production of CO2
concentrations from the monitored piles V1, V2 and V3. In the fourth week, significantly higher
values of CO2 concentrations were recorded from the pile V3 (P < 0.05), which was turned and
irrigated, than from V1 and V2. At week 7, significant differences were found between all
treatments at the significance level (P < 0.05), with the highest values from the V3 pile. It has
been shown that turning and humidifying results in the highest release of CO2 into the air, but in
a more rapid decomposition of the microorganisms, that reducing the time required to achieve a
stable compost product and increasing the efficiency of the composting plant
Anisotropic dielectric function in polar nano-regions of relaxor ferroelectrics
The paper suggests to treat the infrared reflectivity spectra of single
crystal perovskite relaxors as fine-grained ferroelectric ceramics: locally
frozen polarization makes the dielectric function strongly anisotropic in the
phonon frequency range and the random orientation of the polarization at
nano-scopic scale requires to take into account the inhomogeneous
depolarization field. Employing a simple effective medium approximation
(Bruggeman symmetrical formula) to dielectric function describing the polar
optic modes as damped harmonic oscillators turns out to be sufficient for
reproducing all principal features of room temperature reflectivity of PMN. One
of the reflectivity bands is identified as a geometrical resonance entirely
related to the nanoscale polarization inhomogeneity. The approach provides a
general guide for systematic determination of the polar mode frequencies split
by the inhomogeneous polarization at nanometer scale.Comment: 5 pages, 2 figure
Recommended from our members
Identifying causal gateways and mediators in complex spatio-temporal systems
Comment on "On the -Anomaly in Betaine Calcium Chloride Dihydrate"
Recently, Hlinka and Ishibashi [J. Phys. Soc. Jpn. 67, 495 (1998)] discussed
the -anomaly in betaine calcium chloride dihydrate (BCCD) in a Landau-type
approach. We comment on the shortcomings of this approach and discuss the
-anomaly in the framework of a microscopical pseudo spin model based on a
realistic description of BCCD in terms of symmetry-adapted local modes.Comment: 2 pages, RevTex, submitted to J. Phys. Soc. Jp
Regional and inter-regional effects in evolving climate networks
Peer reviewedPublisher PD
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Regional and inter-regional effects in evolving climate networks
Complicated systems composed of many interacting subsystems are frequently studied as complex networks. In the simplest approach, a given real-world system is represented by an undirected graph composed of nodes standing for the subsystems and non-oriented unweighted edges for interactions present among the nodes; the characteristic properties of the graph are subsequently studied and related to the system's behaviour. More detailed graph models may include edge weights, orientations or multiple types of links; potential time-dependency of edges is conveniently captured in so-called evolving networks. Recently, it has been shown that an evolving climate network can be used to disentangle different types of El Niño episodes described in the literature. The time evolution of several graph characteristics has been compared with the intervals of El Niño and La Niña episodes. In this study we identify the sources of the evolving network characteristics by considering a reduced-dimensionality description of the climate system using network nodes given by rotated principal component analysis. The time evolution of structures in local intra-component networks is studied and compared to evolving inter-component connectivity
Magnetodielectric coupling and phonon properties of compressively strained EuTiO3 thin films deposited on LSAT
Compressively strained epitaxial (001) EuTiO3 thin films of tetragonal
symmetry have been deposited on (001) (LaAlO3)_0.29-(SrAl_{1/2}Ta_{1/2}O3)_0.71
(LSAT) substrates by reactive molecular-beam epitaxy. Enhancement of the Neel
temperature by 1 K with 0.9% compressive strain was revealed. The polar phonons
ofthe films have been investigated as a function of temperature and magnetic
field by means of infrared reflectance spectroscopy. All three infrared active
phonons show strongly stiffened frequencies compared to bulk EuTiO3 in
accordance with first principles calculations. The phonon frequencies exhibit
gradual softening on cooling leading to an increase in static permittivity. A
new polar phonon with frequency near the TO1 soft mode was detected below 150
K. The new mode coupled with the TO1 mode was assigned as the optical phonon
from the Brillouin zone edge, which is activated in infrared spectra due to an
antiferrodistortive phase transition and due to simultaneous presence of polar
and/or magnetic nanoclusters. In the antiferromagnetic phase we have observed a
remarkable softening of the lowest-frequency polar phonon under an applied
magnetic field, which qualitatively agrees with first principles calculations.
This demonstrates the strong spin-phonon coupling in EuTiO3, which is
responsible for the pronounced dependence of its static permittivity on
magnetic field in the antiferromagnetic phase.Comment: Submitted to Phys. Rev.
Interaction of Gold Nanoparticles in Barium Titanate Thin Films
A novel approach to control the grain size of oxide thin film materials has
been investigated. Perovskite BaTiO3 shows interesting grain structures when
deposited on gold predeposited, (111)-oriented, singlecrystal SrTiO3
substrates. Solid oxide films grow epitaxially on patterned seed layers and
show variations in grain size relative to the films deposited on SrTiO3
directly.Comment: 14 pages, 4 figure
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