195 research outputs found
Guaranteed state estimation using a bundle of interval observers with adaptive gains applied to the induction machine
he scope of this paper is the design of an interval observer bundle for the guaranteed state estimation of an uncertain induction machine with linear, time-varying dynamics. These guarantees are of particular interest in the case of safety-critical systems. In many cases, interval observers provide large intervals for which the usability becomes impractical. Hence, based on a reduced-order hybrid interval observer structure, the guaranteed enclosure within intervals of the magnetizing currentâs estimates is improved using a bundle of interval observers. One advantage of such an interval observer bundle is the possibility to reinitialize the interval observers at specified timesteps during runtime with smaller initial intervals, based on previously observed system states, resulting in decreasing interval widths. Thus, unstable observer dynamics are considered so as to take advantage of their transient behavior, whereby the overall stability of the interval estimation is maintained. An algorithm is presented to determine the parametrization of reduced-order interval observers. To this, an adaptive observer gain is introduced with which the system states are observed optimally by considering a minimal interval width at variable operating points. Furthermore, real-time capability and validation of the proposed methods are shown. The results are discussed with simulations as well as experimental data obtained with a test bench
High photon flux table-top coherent extreme ultraviolet source
High harmonic generation (HHG) enables extreme ultraviolet radiation with
table-top setups. Its exceptional properties, such as coherence and
(sub)-femtosecond pulse durations, have led to a diversity of applications.
Some of these require a high photon flux and megahertz repetition rates, e.g.
to avoid space charge effects in photoelectron spectroscopy. To date this has
only been achieved with enhancement cavities. Here, we establish a novel route
towards powerful HHG sources. By achieving phase-matched HHG of a megahertz
fibre laser we generate a broad plateau (25 eV - 40 eV) of strong harmonics,
each containing more than photons/s, which constitutes an increase by
more than one order of magnitude in that wavelength range. The strongest
harmonic (H25, 30 eV) has an average power of 143 W (
photons/s). This concept will greatly advance and facilitate applications in
photoelectron or coincidence spectroscopy, coherent diffractive imaging or
(multidimensional) surface science
Nuclear binding near a quantum phase transition
How do protons and neutrons bind to form nuclei? This is the central question
of ab initio nuclear structure theory. While the answer may seem as simple as
the fact that nuclear forces are attractive, the full story is more complex and
interesting. In this work we present numerical evidence from ab initio lattice
simulations showing that nature is near a quantum phase transition, a
zero-temperature transition driven by quantum fluctuations. Using lattice
effective field theory, we perform Monte Carlo simulations for systems with up
to twenty nucleons. For even and equal numbers of protons and neutrons, we
discover a first-order transition at zero temperature from a Bose-condensed gas
of alpha particles (4He nuclei) to a nuclear liquid. Whether one has an
alpha-particle gas or nuclear liquid is determined by the strength of the
alpha-alpha interactions, and we show that the alpha-alpha interactions depend
on the strength and locality of the nucleon-nucleon interactions. This insight
should be useful in improving calculations of nuclear structure and important
astrophysical reactions involving alpha capture on nuclei. Our findings also
provide a tool to probe the structure of alpha cluster states such as the Hoyle
state responsible for the production of carbon in red giant stars and point to
a connection between nuclear states and the universal physics of bosons at
large scattering length.Comment: Published version to appear in Physical Review Letters. Main: 5
pages, 3 figures. Supplemental material: 13 pages, 6 figure
Iron absorption from two milk formulas fortified with iron sulfate stabilized with maltodextrin and citric acid
ABSTRACT: Fortification of milk formulas with iron is a strategy widely used, but the absorption of non-heme iron is low. The purpose of this study was to measure the bioavailability of two iron fortified milk formulas designed to cover toddlersâ nutritional needs. These milks were fortified with iron sulfate stabilized with maltodextrin and citric acid. Methods: 15 women (33â47 years old) participated in study. They received on different days, after an overnight fast, 200 mL of Formula A; 200 mL of Formula B; 30 mL of a solution of iron and ascorbic acid as reference dose and 200 mL of full fat cowâs milk fortified with iron as ferrous sulfate. Milk formulas and reference dose were labeled with radioisotopes 59Fe or 55Fe, and the absorption of iron measured by erythrocyte incorporation of radioactive Fe. Results: The geometric mean iron absorption corrected to 40% of the reference dose was 20.6% for Formula A and 20.7% for Formula B, versus 7.5% of iron fortified cowâs milk (p < 0.001). The post hoc SheffĂ© indeed differences between the milk formulas and the cowâs milk (p < 0.001). Conclusion: Formulas A and B contain highly bioavailable iron, which contributes to covering toddlersâ requirements of this micronutrient
Impact of Nanocomposite Combustion Aerosols on A549 Cells and a 3D Airway Model
The use of nanomaterials incorporated into plastic products is increasing steadily. By using nano-scaled filling materials, thermoplastics, such as polyethylene (PE), take advantage of the unique properties of nanomaterials (NM). The life cycle of these so-called nanocomposites (NC) usually ends with energetic recovery. However, the toxicity of these aerosols, which may consist of released NM as well as combustion-generated volatile compounds, is not fully understood. Within this study, model nanocomposites consisting of a PE matrix and nano-scaled filling material (TiO, CuO, carbon nano tubes (CNT)) were produced and subsequently incinerated using a lab-scale model burner. The combustion-generated aerosols were characterized with regard to particle release as well as compound composition. Subsequently, A549 cells and a reconstituted 3D lung cell culture model (MucilAirâą, Epithelix) were exposed for 4 h to the respective aerosols. This approach enabled the parallel application of a complete aerosol, an aerosol under conditions of enhanced particle deposition using high voltage, and a filtered aerosol resulting in the sole gaseous phase. After 20 h post-incubation, cytotoxicity, inflammatory response (IL-8), transcriptional toxicity profiling, and genotoxicity were determined. Only the exposure toward combustion aerosols originated from PE-based materials induced cytotoxicity, genotoxicity, and transcriptional alterations in both cell models. In contrast, an inflammatory response in A549 cells was more evident after exposure toward aerosols of nano-scaled filler combustion, whereas the thermal decomposition of PE-based materials revealed an impaired IL-8 secretion. MucilAirâą tissue showed a pronounced inflammatory response after exposure to either combustion aerosols, except for nanocomposite combustion. In conclusion, this study supports the present knowledge on the release of nanomaterials after incineration of nano-enabled thermoplastics. Since in the case of PE-based combustion aerosols no major differences were evident between exposure to the complete aerosol and to the gaseous phase, adverse cellular effects could be deduced to the volatile organic compounds that are generated during incomplete combustion of NC
Dietary Intake, Nutritional Adequacy and Food Sources of Total Fat and Fatty Acids, and Relationships with Personal and Family Factors in Spanish Children Aged One to <10 Years: Results of the EsNuPI Study
We aimed to determine the usual intake of total fat, fatty acids (FAs), and their main food
sources in a representative cohort of the Spanish pediatric population aged 1 to <10 years (n = 707)
who consumed all types of milk and an age-matched cohort who consumed adapted milk over the last
year (including follow-on formula, toddlerâs milk, growing-up milk, and fortified and enriched milks)
(n = 741) who were participants in the EsNuPI study (in English, Nutritional Study in the Spanish
Pediatric Population). Dietary intake, measured through two 24 h dietary recalls, was compared to
the European Food Safety Authority (EFSA) and the Food and Agriculture Organization of the United Nations (UN-FAO) recommendations. Both cohorts showed a high intake of saturated fatty acids
(SFAs), according to FAO recommendations, as there are no numerical recommendations for SFAs at
EFSA. Also, low intake of essential fatty acids (EFAs; linoleic acid (LA) and -linolenic acid (ALA))
and long-chain polyunsaturated fatty acids (LC-PUFA) of the n-3 series, mainly docosahexaenoic
acid (DHA) were observed according to EFSA and FAO recommendations. The three main sources of
total fat and di erent FAs were milk and dairy products, oils and fats, and meat and meat products.
The consumption of adapted milk was one of the main factors associated with better adherence to
the nutritional recommendations of total fat, SFAs, EFAs, PUFAs; and resulted as the main factor
associated with better adherence to n-3 fatty acids intake recommendations. Knowledge of the dietary
intake and food sources of total fat and FAs in children could help in designing and promoting
e ective and practical age-targeted guidelines to promote the consumption of EFA- and n-3 PUFA-rich
foods in this stage of life.Instituto Puleva de Nutricion (IPN) - dairy company Lactali
Effects of salt compensation on the climate model response in simulations of large changes of the Atlantic meridional overturning circulation
© 2007 American Meteorological Society (https://www.ametsoc.org/ams/index.cfm/publications/ethical-guidelines-and-ams-policies/ams-copyright-policy/
Subklinische Hypothyreose: Risiken, aktuelle Empfehlungen und randomisierte Studie in der Schweiz
Quintessenz:
⹠Die subklinische Hypothyreose ist definiert durch erhöhte TSH und normwertige ThyroxinSpiegel;
sie kommt bei Ă€lteren Patienten hĂ€ufig vor (10â15%).
⹠Daten aus Beobachtungsstudien zeigen einen möglichen Zusammenhang zwischen der subklinischen Hypothyreose und verschiedenen Krankheitsbildern wie kardiovaskulÀren Erkrankungen, Muskelbeschwerden sowie depressiven oder kognitiven Störungen.
âą Die Indikation zur Thyroxin Substitution bei subklinischer Hypothyreose ist derzeit noch nicht klar, was sich in grossen Unterschieden bezĂŒglich Therapie zwischen verschiedenen LĂ€ndern niederschlĂ€gt. Es zeigt sich jedoch eine Zunahme der ThyroxinVerschreibungen.
âą Die Teilnahme an der randomisierten TRUST Studie ist die derzeit beste «Behandlungsoption» fĂŒr Ă€ltere Patienten mit subklinischer Hypothyreose
- âŠ