1,605 research outputs found
Energy and economic analysis of a residential Solar Organic Rankine plant
To answer the actual energy, water, economic, social and environmental challenges, renewable, distributed power plants need to
be developed. Among renewables, solar tri-generative power plants can be a solution where there is big low temperature
heating/cooling demand and small electricity demand, like many residential and industrial utilities. In this case, solar thermal
plants can produce thermal energy with low cost and high efficiency. The higher temperature heat not needed by the user can be
exploited via Organic Rankine Cycle to produce electrical energy and desalinized water via reverse osmosis. The present paper
analyses, via TRNSYS simulation, a system composed of 50 m2
of CPC solar thermal collectors, 3 m3
of thermal storage, a
synthetic heat transfer fluid, 3 kWe ORC, 8 kWth absorber, 200 l/h direct reverse osmosis desalination device. The system is able
to produce power, heating/cooling and fresh water needs for a residential house. Although system’s components are well known
technologies, the integration to a efficient and economic working system is still a challenge. Global energy and economic
analyses have been performed. Low temperature heating/cooling terminals allow to increase not only the use of thermal energy
but also the ORCand absorber efficiency. ORC-Absorber configuration and relative fluids and temperatures are central.
Government support and/or cost reduction of 30% are necessary to have positive NPV and acceptable PBT and IR
Optical Response of SrRuO Reveals Universal Fermi-liquid Scaling and Quasiparticles Beyond Landau Theory
We report optical measurements demonstrating that the low-energy relaxation
rate () of the conduction electrons in SrRuO obeys scaling
relations for its frequency () and temperature () dependence in
accordance with Fermi-liquid theory. In the thermal relaxation regime,
1/\tau\propto (\hbar\omega)^2 + (p\pi\kB T)^2 with , and
scaling applies. Many-body electronic structure calculations using dynamical
mean-field theory confirm the low-energy Fermi-liquid scaling, and provide
quantitative understanding of the deviations from Fermi-liquid behavior at
higher energy and temperature. The excess optical spectral weight in this
regime provides evidence for strongly dispersing "resilient" quasiparticle
excitations above the Fermi energy
Chiral spin currents and spectroscopically accessible single merons in quantum dots
We provide unambiguous theoretical evidence for the formation of
correlation-induced isolated merons in rotationally-symmetric quantum dots. Our
calculations rely on neither the lowest-Landau-level approximation, nor on the
maximum-density-droplet approximation, nor on the existence of a spin-polarized
state. For experimentally accessible system parameters, unbound merons condense
in the ground state at magnetic fields as low as T and for as few
as N = 3 confined fermions. The four-fold degenerate ground-state at
corresponds to four orthogonal merons characterized by their
topological chirality and charge . This degeneracy is lifted by the
Rashba and Dresselhaus spin-orbit interaction, which we include perturbatively,
yielding spectroscopic accessibility to individual merons. We further derive a
closed-form expression for the topological chirality in the form of a chiral
spin current and use it to both characterize our states and predict the
existence of other topological textures in other regions of phase space, for
example, at N=5. Finally, we compare the spin textures of our numerically exact
meron states to ansatz wave-functions of merons in quantum Hall droplets and
find that the ansatz qualitatively describes the meron states.Comment: 4 pages, 5 figures; minor title change, typos fixe
Effect of water deficit and severe shoot trimming on the composition of Vitis vinifera L. Merlot grapes and wines
The role of evidence in nutrition policymaking in Ethiopia: institutional structures and issue framing
Malnutrition is the single greatest contributor to the global burden of morbidity and mortality, with most cases arising in low‐ and middle‐income countries. However, the multi‐sectoral nature of nutrition policy‐making adds considerable complexity to the implementation of effective programmes. This raises questions about why or how relevant policy change can come about within different country settings. This article examines multi‐sectoral nutrition policy‐making from the health sector perspective, specifically focusing on different sectoral perspectives and the role and use of evidence within this. Ethiopia provides a unique example of the challenging nature of multi‐sectoral nutrition policy‐making, even with a strong co‐ordinating infrastructure. In December 2014 we undertook 23 in‐depth semi‐structured interviews with stakeholders from key health sector organizations, along with a related documentary analysis. Participants represented a diverse range of perspectives, including government representatives, policy stakeholders, aid providers from multi‐lateral organizations and academic researchers. Our respondents described how nutrition framing in Ethiopia is changing, with greater consideration of overweight, obesity and non‐communicable diseases, as well as undernutrition and micronutrient deficiencies. However, overweight‐ and obesity‐related concerns are still less evident in key documents. Some health actors described the challenge of enacting structural policy changes when doing so requires engagement from the agriculture sector. While multi‐sectoral plans and infrastructure to address malnutrition are in place, respondents suggested that the mandate for addressing nutrition resting with the health sector was reinforced by the nature of evidence collected. This study of nutrition policy‐making in Ethiopia highlights the complex interaction of evidence within different conceptualisations of policy problems and responses. Despite Ethiopia's strategic framework and its progress in achieving terms of nutrition targets, it shares the challenge of countries elsewhere in addressing nutrition as a multi‐sectoral issue
Stacking order dynamic in the quasi-two-dimensional dichalcogenide 1T-TaS probed with MeV ultrafast electron diffraction
Transitions between different charge density wave (CDW) states in
quasi-two-dimensional materials may be accompanied also by changes in the
inter-layer stacking of the CDW. Using MeV ultrafast electron diffraction, the
out-of-plane stacking order dynamics in the quasi-two-dimensional
dichalcogenide 1T-TaS is investigated for the first time. From the
intensity of the CDW satellites aligned around the commensurate = 1/6
characteristic stacking order, it is found out that this phase disappears with
a 0.5 ps time constant. Simultaneously, in the same experiment, the emergence
of the incommensurate phase, with a slightly slower 2.0 ps time constant, is
determined from the intensity of the CDW satellites aligned around the
incommensurate = 1/3 characteristic stacking order. These results might be
of relevance in understanding the metallic character of the laser-induced
metastable "hidden" state recently discovered in this compound
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