8,246 research outputs found
Effect of Heating Rates and Composition on the Thermal Decomposition of Nitrate Based Molten Salts
AbstractA detailed analysis on the thermal degradation of nitrate based molten salts evaluating the influence of different impurities and heating rates in their maximum working temperature is presented. Determining the maximum operating temperature is of interest when searching for new heat transfer fluids (HTF) for high temperature solar thermal applications as it limits the thermodynamic efficiency of the power block. Thermogravimetric analysis is performed on potassium nitrate, sodium nitrate, sodium nitrite, the binary system Solar Salt, and the ternary Hitec. The kinetics of the thermal decomposition reactions are investigated through iso-conversional analysis. The effect of adding some common impurities such us NaCl and Na2CO3 on the multi-component nitrate salts is evaluated. It was found that impurities such as Na2CO3 can enhance the thermal stability of Hitec salt, leading to higher thermal decomposition temperatures. For solar salt, impurities such as NaCl can enhance the thermal stability of solar salt at 10K·min-1, while adding Na2CO3 can have the opposite effect. For nitrate based molten salts used in TES and HTF systems in CSP a reduction on the purity required for the materials can present some operational advantages besides cost reduction
Parasitic plants--A CuRe for what ails thee
Parasitic plants cause dramatic changes in ecosystems and represent a serious risk to agriculture by attacking crops of high economic importance. A highly conserved part of plant immune systems is the recognition of microbe-associated molecular patterns (MAMPs) by plasma membrane-localized pattern recognition receptors (PRRs) that initiate an effective immune response upon activation (1). Whether parasitic plants are also sensed as foes by these receptors was until now unknown. On page 478 of this issue, Hegenauer et al. report the identification of a canonical PRR that is required for responsiveness to a MAMP-like molecule from the parasitic plant Cuscuta reflexa and protects plants against parasitic attack (2). This finding opens the possibility of biotechnological applications for sustainable crop protection against these devastating parasites
Topological Hunds rules and the electronic properties of a triple lateral quantum dot molecule
We analyze theoretically and experimentally the electronic structure and
charging diagram of three coupled lateral quantum dots filled with electrons.
Using the Hubbard model and real-space exact diagonalization techniques we show
that the electronic properties of this artificial molecule can be understood
using a set of topological Hunds rules. These rules relate the multi-electron
energy levels to spin and the inter-dot tunneling , and control charging
energies. We map out the charging diagram for up to N=6 electrons and predict a
spin-polarized phase for two holes. The theoretical charging diagram is
compared with the measured charging diagram of the gated triple-dot device.Comment: 31 pages, 7 figures, accepted to March 15, 2007 issue of Phys. Rev.
B, vol. 7
Cancer du sein, mécanismes de défense et psychose
International audienceSome severe diseases as cancer provoke into patients important defensive strategies. This work explores the specificity of defenses implemented in the case of two female psychotic patients suffering of breast cancer – a pranoiac and a schizophrenic – as well as the effetc produced on a hallucinatory and delusion constructions.Certaines maladies somatiques graves, comme le cancer, provoquent des stratégies défensives importantes chez les patients. Ce travail explore la spécificité des mécanismes de défense mis en oeuvre dans le cas de deux patientes psychotiques atteintes d'un cancer du sein - une paranoïaque et une schizophrène - ainsi que l'effet produit sur les constructions délirantes et hallucinatoires
L'utilisation du processus de clivage chez une patiente cas-limite: RĂ©flexion diagnostique et psychopathologique
International audienceFrom a clinical case concerning an ambulatory pathological non-selfcare without associated clinical signs and with a notably good social and professional fitting, authors present a psychopathological discussion. They discuss differntial diagnosis between obsessional neurosis, psychosis and borderliner case.A partir d'un cas clinique concernant une incurie à domicile sans signes cliniques associés, et avec notamment une bonne adaptation socio-professionnelle, les auteurs développent une discussion psychopathologique. Après l'étude du diagnostic différentiel, entre névrose obsessionnelle, psychose et état-limite, les auteurs soutiennent l'utilisation de mécanismes de défense tels que le clivage massif, chez un sujet cas-limite
A review of aceclofenac: Analgesic and anti-inflammatory effects on musculoskeletal disorders
Aceclofenac is an oral non-steroidal anti-inflammatory drug (NSAID) with antiinflammatory and analgesic properties. Although there are some differences in the authorized indications between countries, aceclofenac is mainly recommended for the treatment of inflammatory and painful processes, such as low back pain (LBP), scapulohumeral periarthritis, extraarticular rheumatism, odontalgia, and osteoarthritis (OA), rheumatoid arthritis (RA), and ankylosing spondylitis (AS). The analgesic properties and tolerability profile of aceclofenac in musculoskeletal disorders are reviewed, focusing on relevant and recent studies. The efficacy and safety comparison of aceclofenac with other analgesics and anti-inflammatory agents in OA, AS, RA, and LBP is described. Relevant studies were identified following a literature search of PubMed using the terms “aceclofenac” and “clinical trials” published from 1 Jan 1992 to 1 Jan 2020. Aceclofenac is at least as effective as other NSAIDs in reducing pain and/or improving functional capacity in chronic pain conditions (OA, AS, RA, and LBP). It is generally well tolerated and appears to have a more favorable GI profile than other NSAIDs. Thus, current evidence indicates that aceclofenac is a useful option for the management of pain and inflammation across a wide range of painful conditions
K^0-\bar{K}^0 mixing in the Standard Model from Nf=2+1+1 Twisted Mass Lattice QCD
We present preliminary results at {\beta} = 1.95 (a = 0.077 fm) on the first
unquenched N_f=2+1+1 lattice computation of the B_K parameter which controls
the neutral kaon oscillations in the Standard Model. Using N_f=2+1+1 maximally
twisted sea quarks and Osterwalder-Seiler valence quarks we achieve O(a)
improvement and a continuum-like renormalization pattern for the four-fermion
operator. Our results are extrapolated/interpolated to the physical
light/strange quark mass but not yet to the continuum limit. The computation of
the relevant renormalization constants is performed non perturbatively in the
RI'-MOM scheme using dedicated simulations with N_f=4 degenerate sea quark
flavours produced by the ETM collaboration.
We get B_K^{RGI} (a = 0.077) = 0.747(18), which when compared to our previous
unquenched N_f=2 determination and most of the existing results, suggests a
rather weak B_K^{RGI} dependence on the number of dynamical flavours. We are at
the moment analysing lattice data at two additional {\beta} values which will
allow us to perform an extrapolation to the continuum limit.Comment: 7 pages, 8 figures, Proceedings of Lattice 2011, XXIX International
Symposium on Lattice Field Theory, Squaw Valley, Lake Tahoe, Californi
K^0-\bar{K}^0 Mixing Beyond the SM from Nf=2 tmQCD
We present preliminary results on the of neutral kaon oscillations in
extensions of the Standard Model. Using Nf=2 maximally twisted sea quarks and
Osterwalder-Seiler valence quarks, we achieve both O(a)-improvement and
continuum-like renormalization pattern for the relevant four-fermion operators.
We perform simulations at three values of the lattice spacing and
extrapolate/interpolate our results to the continuum limit and physical
light/strange quark mass. The calculation of the renormalization constants of
the complete operator basis is performed non- perturbatively in the RI-MOM
scheme.Comment: 7 pages, 2 figures; presented at the XXVIII International Symposium
on Lattice Field Theory Villasimius, Sardinia, Ital
Kaon oscillations in the Standard Model and Beyond using Nf=2 dynamical quarks
We compute non-perturbatively the B-parameters of the complete basis of
four-fermion operators needed to study the Kaon oscillations in the SM and in
its supersymmetric extension. We perform numerical simulations with two
dynamical maximally twisted sea quarks at three values of the lattice spacing
on configurations generated by the ETMC. Unwanted operator mixings and O(a)
discretization effects are removed by discretizing the valence quarks with a
suitable Osterwalder-Seiler variant of the Twisted Mass action. Operators are
renormalized non-perturbatively in the RI/MOM scheme. Our preliminary result
for BK(RGI) is 0.73(3)(3).Comment: 7 pages, 3 figures, 1 table, proceedings of the XXVII Int'l Symposyum
on Lattice Field Theory (LAT2009), July 26-31 2009, Peking University,
Beijing (China
Quark and Gluon Propagators in Covariant Gauges
We present data for the gluon and quark propagators computed in the standard
lattice Landau's gauge and for three values of the covariant gauge-fixing
parameter lambda=0,8,16. Our results are obtained using the SU(3) Wilson action
in the quenched approximation at beta=6.0 and volume=16^3x32.Comment: Lattice2001(theorydevelop
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