4,143 research outputs found
Control of heat pumps with CO2 emission intensity forecasts
An optimized heat pump control for building heating was developed for
minimizing CO2 emissions from related electrical power generation. The control
is using weather and CO2 emission forecasts as input to a Model Predictive
Control (MPC) - a multivariate control algorithm using a dynamic process model,
constraints and a cost function to be minimized. In a simulation study the
control was applied using weather and power grid conditions during a full year
period in 2017-2018 for the power bidding zone DK2 (East, Denmark). Two
scenarios were studied; one with a family house and one with an office
building. The buildings were dimensioned on the basis of standards and building
codes. The main results are measured as the CO2 emission savings relative to a
classical thermostatic control. Note that this only measures the gain achieved
using the MPC control, i.e. the energy flexibility, not the absolute savings.
The results show that around 16% savings could have been achieved during the
period in well insulated new buildings with floor heating.
Further, a sensitivity analysis was carried out to evaluate the effect of
various building properties, e.g. level of insulation and thermal capacity.
Danish building codes from 1977 and forward was used as benchmarks for
insulation levels. It was shown that both insulation and thermal mass influence
the achievable flexibility savings, especially for floor heating. Buildings
that comply with codes later than 1979 could provide flexibility emission
savings of around 10%, while buildings that comply with earlier codes provided
savings in the range of 0-5% depending on the heating system and thermal mass.Comment: 16 pages, 12 figures. Submitted to Energie
Late Cenozoic metamorphic evolution and exhumation of Taiwan
The Taiwan mountain belt is composed of a Cenozoic slate belt (Hsuehshan Range units, HR, and Backbone Slates, BS) and of accreted polymetamorphic basement rocks (Tananao Complex, TC). Ongoing crustal shortening has resulted from the collision between the Chinese continental margin and the Luzon volcanic arc, which initiated ~6.5 Ma ago. The grade and age of metamorphism and exhumation are a key record of the development of the orogenic wedge. Because the Taiwan mountain belt is mostly composed by accreted sediments lacking metamorphic index minerals, quantitative constraints on metamorphism are sparse. By contrast, these rocks are rich in carbonaceaous material (CM) and are therefore particularly appropriate for RSCM (Raman Spectroscopy of CM) thermometry. We apply this technique in addition to (U-Th)/He thermochronology on detrital zircons to assess peak metamorphic temperatures (T) and the late exhumational history respectively, along different transects in central and southern Taiwan. In the case of the HR units, we find evidence for high metamorphic T of at least 340°–350°C and locally up to 475°C, and for relative rapid exhumation with zircon (U-Th)/He ages in the range of 1.5–2 Ma. Farther east, the BS were only slightly metamorphosed (T < 330 °C), and zircons are not reset for (U-Th)/He. From the eastern BS to the inner TC schists, T gradually increases from ~350°C up to ~500°C following an inverted metamorphic gradient. Available geochronological constraints and the continuous thermal gradient from the BS to the basement rocks of the TC suggest that the high RSCM T of the TC were most probably acquired during the last orogeny, and were not inherited from a previous thermal event. Zircons yield (U-Th)/He ages of ~0.5–1.2 Ma. Peak metamorphic T and the timing of exhumation do not show along-strike variations over the TC in the studied area. In contrast, exhumation is laterally diachronous and decreases southward in the case of the HR units. In particular, our data imply that the HR units have been exhumed by a minimum of 15 km over the last few Ma. In the case of the BS, they show far less cumulated exhumation and much slower cooling rates. We propose that most of the deformation and exhumation of the Taiwan mountain belt is sustained through two underplating windows located beneath the Hsuehshan Range and the TC. Our data show significant departures from the predictions of the prevailing model in Taiwan, which assumes a homogeneous critical wedge with dominant frontal accretion. Our study sheds new light on how the mountain belt has grown as a possible result of underplating mostly
Social media and political communication in the 2014 elections to the European Parliament
Social media play an increasingly important part in the communication strategies of political campaigns by reflecting information about the policy preferences and opinions of political actors and their public followers. In addition, the content of the messages provides rich information about the political issues and the framing of those issues during elections, such as whether contested issues concern Europe or rather extend pre-existing national debates. In this study, we survey the European landscape of social media using tweets originating from and referring to political actors during the 2014 European Parliament election campaign. We describe the language and national distribution of the messages, the relative volume of different types of communications, and the factors that determine the adoption and use of social media by the candidates. We also analyze the dynamics of the volume and content of the communications over the duration of the campaign with reference to both the EU integration dimension of the debate and the prominence of the most visible list-leading candidates. Our findings indicate that the lead candidates and their televised debate had a prominent influence on the volume and content of communications, and that the content and emotional tone of communications more reflects preferences along the EU dimension of political contestation rather than classic national issues relating to left-right differences
Regulation of High Affinity Choline Uptake and Its Influence on Age-related Differences in Sensitivity to Organophosphorus Insecticides
Veterinary Biomedical Science
Observation of quantum depletion in a nonequilibrium exciton-polariton condensate
The property of superfluidity, first discovered in liquid 4He, is closely
related to Bose-Einstein condensation (BEC) of interacting bosons. However,
even at zero temperature, when one would expect the whole bosonic quantum
liquid to become condensed, a fraction of it is excited into higher momentum
states via interparticle interactions and quantum fluctuations -- the
phenomenon of quantum depletion. Quantum depletion of weakly interacting atomic
BECs in thermal equilibrium is well understood theoretically but is difficult
to measure. This is even more challenging in driven-dissipative systems such as
exciton-polariton condensates(photons coupled to electron-hole pairs in a
semiconductor), since their nonequilibrium nature is predicted to suppress
quantum depletion. Here, we observe quantum depletion of an optically trapped
high-density exciton-polariton condensate by directly detecting the spectral
branch of elementary excitations populated by this process. Analysis of the
population of this branch in momentum space shows that quantum depletion of an
exciton-polariton condensate can closely follow or strongly deviate from the
equilibrium Bogoliubov theory, depending on the fraction of matter (exciton) in
an exciton-polariton. Our results reveal the effects of exciton-polariton
interactions beyond the mean-field description and call for a deeper
understanding of the relationship between equilibrium and nonequilibrium BECs.Comment: 18 pages, 5 figures, with supplementary informatio
Zr and Hf microalloying in an Al-Y-Fe amorphous alloy. Relation between local structure and glass-forming ability
International audienceThe effects of the addition of small amounts of Zr and Hf (0.5 - 3 %) on the atomic structure of Al88Y7Fe5 metallic glass were examined from extended x-ray absorption fine structure (EXAFS) experiments to better understand the influence of these microadditions on the glass forming ability of this alloy. Measurements at the Zr K and Hf LIII absorption edges have allowed the local structures around Zr and Hf atoms to be determined. The same Al environment was found for the different concentrations, consisting of a small cluster extending up to 4.5 Ã… around the Zr atoms and up to 6 Ã… around the Hf ones. Although the clustering effect is smaller in the Zr neighbourhood, a drastic shortening of the nearest Zr-Al distance is shown, providing evidence for some covalent character to the bonding, in line with the increased glass-forming ability found in the alloys made with the Zr microaddition
Inhibition of mTORC1 Enhances the Translation of Chikungunya Proteins via the Activation of the MnK/eIF4E Pathway
International audienceChikungunya virus (CHIKV), the causative agent of a major epidemic spanning five continents, is a positive stranded mRNA virus that replicates using the cell's cap-dependent translation machinery. Despite viral infection inhibiting mTOR, a metabolic sensor controls cap-dependent translation, viral proteins are efficiently translated. Rapalog treatment, silencing of mtor or raptor genes, but not rictor, further enhanced CHIKV infection in culture cells. Using biochemical assays and real time imaging, we demonstrate that this effect is independent of autophagy or type I interferon production. Providing in vivo evidence for the relevance of our findings, mice treated with mTORC1 inhibitors exhibited increased lethality and showed a higher sensitivity to CHIKV. A systematic evaluation of the viral life cycle indicated that inhibition of mTORC1 has a specific positive effect on viral proteins, enhancing viral replication by increasing the translation of both structural and nonstructural proteins. Molecular analysis defined a role for phosphatidylinositol-3 kinase (PI3K) and MAP kinase-activated protein kinase (MnKs) activation, leading to the hyper-phosphorylation of eIF4E. Finally, we demonstrated that in the context of CHIKV inhibition of mTORC1, viral replication is prioritized over host translation via a similar mechanism. Our study reveals an unexpected bypass pathway by which CHIKV protein translation overcomes viral induced mTORC1 inhibition
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