1,515 research outputs found
Water vapor mapping by fusing InSAR and GNSS remote sensing data and atmospheric simulations
Data fusion aims at integrating multiple data sources that can be redundant or complementary to produce complete, accurate information of the parameter of interest. In this work, data fusion of precipitable water vapor (PWV) estimated from remote sensing observations and data from the Weather Research and Forecasting (WRF) modeling system are applied to provide complete grids of PWV with high quality. Our goal is to correctly infer PWV at spatially continuous, highly resolved grids from heterogeneous data sets. This is done by a geostatistical data fusion approach based on the method of fixed-rank kriging. The first data set contains absolute maps of atmospheric PWV produced by combining observations from the Global Navigation Satellite Systems (GNSS) and Interferometric Synthetic Aperture Radar (InSAR). These PWV maps have a high spatial density and a millimeter accuracy; however, the data are missing in regions of low coherence (e.g., forests and vegetated areas). The PWV maps simulated by the WRF model represent the second data set. The model maps are available for wide areas, but they have a coarse spatial resolution and a still limited accuracy. The PWV maps inferred by the data fusion at any spatial resolution show better qualities than those inferred from single data sets. In addition, by using the fixed-rank kriging method, the computational burden is significantly lower than that for ordinary kriging. © 2015 Author(s)
Energy efficiency (EE) and cost-effective means to increase EE and to mitigate the climate change of pork and broiler meat production in five European countries
Production of pork and broiler meat in the European Union (EU) has increased by 7.8
and 16.1%, respectively, in the period of 2001 – 2011. At that time pork and broiler
meat produced, amounted together to over four times the cattle meat. Meat is an important
protein source in human diet, but on the other hand, livestock uses globally
30% of ice-free terrestrial land and produces 18% of global greenhouse gas (GHG)
emissions. This exceeds the global emissions of the transport sector. Furthermore,
energy ratio (output/input) for meat production is less than 1.0 in general and it is
much lower than that of plant production. This paper presents cost-effectiveness of
EE measures in pork and broiler meat production and it is based on the results of the
Agriculture and Energy Efficiency Project (www.AGREE.aua.gr).
The structure of the energy input appeared to be very similar in pork and broiler meat
production. Feed was found to be the major indirect energy input. Its contribution to
the total energy demand varied from 51% to 82% in pork production and from 55% to
94% in broiler meat production. The percentage of feed was the lowest in the Northern
European countries and the highest in the south. This difference was mainly attributable
to the demand for heating of animal houses during the winter period. Differences
could also be found in the absolute energy input of feed. It indicated that
there may be possibilities to improve feeding strategies or feed conversation rate of
animals. In pork production, the energy input of feed was 12.5 GJ t-1 (live weight) in
average and 8.6 GJ t-1 (live weight) in broiler production. The difference between pork
and broiler meat is a consequence of the higher feed conversation rate of broilers in
contrast to pigs. The category “Other energy use” was the second highest energy input and it consisted of energy input for ventilation, illumination, feeding, and heating
of animal houses. In pork production, the input of this category was 4.7 GJ t-1 (live
weight) in average (25% from the total energy input) and 2.4 GJ t-1 (live weight) in
broiler meat production (22% from the total energy input). The specific energy input
in pork production was the lowest in The Netherlands ( 14.5 GJ t-1) and that of broiler
meat production in Germany (9.8 GJ t-1).
Case studies analysed in five participating countries demonstrated EE measures capable
to reduce costs, to increase EE, and to cut GHG emissions at the same time.
Proposed EE measures were related to ventilation, heating, feeding, animal bedding,
energy generation from manure, and feed production. As an example, an airtight
grain storage met all three goals at the same time. Investment costs were lower than
those for a grain dryer, no energy was needed for drying, and no GHG emissions
were generated because no gas or oil was needed for drying. All suggested EE
measures were not as successful. They might appear negative for costs but positive
for EE and GHG reduction, resulting in a trade-off situation. An approach like this
helps to rank potential EE measures in terms of their cost-effectiveness and capability
to cut GHG emissions
Comparative Analysis of Energy Efficiency in Wheat Production in Different Climate Conditions of Europe
This paper presents results concerning energy efficiency of wheat production considered in the context of specific energy
input variation in different climatic conditions of Europe as well as case studies on implementation of selected energy saving
measures in practice. The source data collected from the six european union (EU) countries represent five agricultural regions of
continental Europe and three climates: continental, temperate and Mediterranean. The life cycle assessment (LCA) methodology was
applied to analyze the data excluding of pre-farm gate activities. The total primary energy consumption was decomposed into main
energy input streams and it was regressed to yield. In order to compare energy efficiency of wheat production across the geographical
areas, the data envelopment analysis (DEA) was applied. It was shown that the highest wheat yield (6.7 t/ha to 8.7 t/ha) at the lowest
specific energy input (2.08 GJ/t to 2.56 GJ/t) is unique for temperate climate conditions. The yield in continental and Mediterranean
climatic conditions is on average lower by 1.3 t/ha and 2.7 t/ha and energy efficiency lower by 14% and 38%, respectively. The case
studies have shown that the energy saving activities in wheat production may be universal for the climatic zones or specific for a
given geographical location. It was stated that trade-offs between energy, economic, and environmental effects, which are associated
with implementation of a given energy saving measure or a set of measures to a great extent depend on the current energy efficiency
status of the farm and opportunity for investment, which varies substantially across Europe
Про участь НАН України в розробці наукових основ сталого розвитку України
Наведено основні напрями наукових досліджень установ НАН України з проблеми збереження навколишнього середовища і сталого розвитку України, що виконувались наприкінці ХХ та на початку ХХІ століть в світлі рішень Конференції ООН з навколишнього середовища і розвитку у Ріо-де-Жанейро (червень 1992 р.) та Всесвітнього саміту зі сталого розвитку в Йоганнесбурзі (26 серпня — 4 вересня 2002 р.). На основі узагальнення результатів опитування установ НАН України в 2005 році проведено кількісний (наукометричний) аналіз їх участі у вирішенні зазначеної міждисциплінарної проблеми за п’ятирічний період за рядом показників (фінансове і кадрове забезпечення досліджень, використання їх результатів, патентно-ліцензійна та видавнича діяльність тощо) і сформульовано пропозиції щодо здійснення відповідних заходів з підвищення ефективності використання фінансових і матеріальних ресурсів при виконанні наукових досліджень з проблеми, підвищення їх координації та результативності.Приведены основные направления научных исследований учреждений НАН Украины по проблеме сохранения окружающей среды и стойкого развития Украины, которые выполнялись в конце ХХ и в начале XXI столетий в свете решений Конференции ООН по окружающей среде и развитию в Рио-де-Жанейро (июнь 1992 г.) и Всемирного саммита по устойчивому развитию в Иоганнесбурге (26 августа — 4 сентября 2002 г.). На основе обобщения результатов опроса учреждений НАН Украины в 2005 году проведен количественный (наукометрический) анализ их участия в решении указанной междисциплинарной проблемы за пятилетний период по ряду показателей (финансовое и кадровое обеспечение исследований, использование их результатов, патентно-лицензионная и издательская деятельность и др.) и сформулированы предложения о выполнении соответствующих мероприятий по повышению эффективности использования финансовых и материальных ресурсов при выполнении научных исследований по проблеме, повышению их координации и результативности.Main areas for research in institutes of the Ukrainian NAS are shown, devoted to environmental protection and sustained development in Ukraine, performed at the end of XX and the beginning of XXI centuries in light of the decision taken by the UN Conference in Rio de Janeiro (June 1992) and the World Summit on Sustained Development in Johannesburg (26 August – 4 September 2002). On the basis of results from a survey on institutes of the Ukrainian NAS, conducted in 2005, a scientometric analysis of their contributions in solving the above interdisciplinary problem is made, covering the 5-year period, by several indicators (research funding and personnel, applications of results, patenting, licensing, printing and publishing etc.), and measures are offered to enhance the efficiency of relevant research in terms of resource utilization, coordination and produced results
Energy efficiency in agriculture
One of the EU headline target indicators for Europe is “20% increase in energy efficiency” by 2020.
It is anticipated that in the following decades energy use will increase significantly and will have a widespread impact
on the economy, including the agricultural sector. Energy use reduction can be achieved by reduced energy input.
Improved energy efficiency, however, is only achieved, if energy input per unit yield is reduced. Therefore, improved
energy efficiency can be realized with either increased or decreased energy inputs depending on the input-output
relationship. In agricultural production the need for energy as an input can determine the profitability of farming which,
in turn, impacts heavily upon the farmers’ investment in improved farming systems.
This paper presents some of the results obtained in the WP2 of the KBBE.2011.4-04 project “Energy Efficiency in
Agriculture - AGREE” supported by the 7th Framework Program. It gives an overview into energy use and energy
efficiency of agriculture in various agro-climatic zones of Europe
Edge effects and vertical stratification of aerial insectivorous bats across the interface of primary-secondary Amazonian rainforest
Research ArticleEdge effects, abiotic and biotic changes associated with habitat boundaries, are key drivers
of community change in fragmented landscapes. Their influence is heavily modulated by
matrix composition. With over half of the world’s tropical forests predicted to become forest
edge by the end of the century, it is paramount that conservationists gain a better understanding
of how tropical biota is impacted by edge gradients. Bats comprise a large fraction
of tropical mammalian fauna and are demonstrably sensitive to habitat modification. Yet,
knowledge about how bat assemblages are affected by edge effects remains scarce. Capitalizing
on a whole-ecosystem manipulation in the Central Amazon, the aims of this study
were to i) assess the consequences of edge effects for twelve aerial insectivorous bat species
across the interface of primary and secondary forest, and ii) investigate if the activity
levels of these species differed between the understory and canopy and if they were modulated
by distance from the edge. Acoustic surveys were conducted along four 2-km transects,
each traversing equal parts of primary and ca. 30-year-old secondary forest. Five
models were used to assess the changes in the relative activity of forest specialists (three
species), flexible forest foragers (three species), and edge foragers (six species). Modelling
results revealed limited evidence of edge effects, except for forest specialists in the understory.
No significant differences in activity were found between the secondary or primary forest
but almost all species exhibited pronounced vertical stratification. Previously defined bat
guilds appear to hold here as our study highlights that forest bats are more edge-sensitive
than edge foraging bats. The absence of pronounced edge effects and the comparable
activity levels between primary and old secondary forests indicates that old secondary forest can help ameliorate the consequences of fragmentation on tropical aerial insectivorous
batsinfo:eu-repo/semantics/publishedVersio
Vibrational Properties of Nanoscale Materials: From Nanoparticles to Nanocrystalline Materials
The vibrational density of states (VDOS) of nanoclusters and nanocrystalline
materials are derived from molecular-dynamics simulations using empirical
tight-binding potentials. The results show that the VDOS inside nanoclusters
can be understood as that of the corresponding bulk system compressed by the
capillary pressure. At the surface of the nanoparticles the VDOS exhibits a
strong enhancement at low energies and shows structures similar to that found
near flat crystalline surfaces. For the nanocrystalline materials an increased
VDOS is found at high and low phonon energies, in agreement with experimental
findings. The individual VDOS contributions from the grain centers, grain
boundaries, and internal surfaces show that, in the nanocrystalline materials,
the VDOS enhancements are mainly caused by the grain-boundary contributions and
that surface atoms play only a minor role. Although capillary pressures are
also present inside the grains of nanocrystalline materials, their effect on
the VDOS is different than in the cluster case which is probably due to the
inter-grain coupling of the modes via the grain-boundaries.Comment: 10 pages, 7 figures, accepted for publication in Phys. Rev.
Effect of isotopic mass on the photoluminescence spectra of beta zinc sulfide
Zinc sulfide is a wide bandgap semiconductor which crystallizes in either the
wurtzite modification (a-ZnS), the zincblende modification (b-ZnS) or as one of
several similar tetrahedrally coordinated polytypes. In this work, we report a
photoluminescence study of different samples of isotopically pure b-ZnS
crystals, and crystals with the natural isotopic abundances, at 15 and 77 K.
The derivatives of the free and bound exciton energies on isotopic mass have
been obtained. They allow us to estimate the contribution of the zinc and
sulfur vibrations to the bandgap renormalization energy by electron-phonon
interaction. A two-oscillator model based on the zinc and sulfur
renormalization energies has been used to account for the temperature
dependence of the bandgap energy in ZnS. The results are compared with those
found for other tetrahedrally coordinated semiconductors.Comment: 19 pages, 4 Postscript figures, sent to Solid State Communication
Phase coherence phenomena in superconducting films
Superconducting films subject to an in-plane magnetic field exhibit a gapless
superconducting phase. We explore the quasi-particle spectral properties of the
gapless phase and comment on the transport properties. Of particular interest
is the sensitivity of the quantum interference phenomena in this phase to the
nature of the impurity scattering. We find that films subject to columnar
defects exhibit a `Berry-Robnik' symmetry which changes the fundamental
properties of the system. Furthermore, we explore the integrity of the gapped
phase. As in the magnetic impurity system, we show that optimal fluctuations of
the random impurity potential conspire with the in-plane magnetic field to
induce a band of localized sub-gap states. Finally, we investigate the
interplay of the proximity effect and gapless superconductivity in thin normal
metal-superconductor bi-layers.Comment: 13 pages, 8 figures include
- …