Simple Electromagnetic Motor Model for Torsional Analysis of Variable Speed Drives with an Induction Motor

Torsional vibrations must be considered in the design of all high-power drive-trains including an induction motor. Electromagnetic (EM) field in the air gap of an induction motor generates additional magnetic stiffness and damping between the rotor and stator. The inclusion of these magnetic effects is limited by the availability of simple and portable motor models. The main aim of this paper is to introduce a motor model including the speed and torque variation. The presented model is based on the linearization of the common space-vector models of induction motors. The parameters of this model are identified for the rated operating condition. This motor model can be extended to include variable speed and torque operation. The numerical results demonstrate that this model describes accurately the magnetic effects over the large speed and torque range. In addition, the numerical results demonstrate the significance of magnetic stiffness and damping in variable speed motor-driven compressors with a soft coupling

Aivotoiminnan häiriöiden yhteydessä yleisesti koetut psykososiaaliset vaikeudet : PARADISE24-kyselyn tutkimusperusta

Ihmisen kokonaistilanne on tärkeä ottaa hoidossa ja kuntoutuksessa huomioon. Psychosocial Factors Relevant to Brain Disorders in Europa (PARADISE) -hanke toteutettiin kymmenen instituutin yhteistyössä professori Ciezan johdolla 2010–2013. Tavoitteena oli kehittää tutkimukseen perustuva menetelmä, jonka avulla voidaan kartoittaa psykososiaalisia vaikeuksia eri aivotoiminnan häiriöiden hoidossa, kuntoutuksessa ja tutkimisessa. Hankkeessa oli lähtökohtana oletus psykososiaalisten vaikeuksien horisontaalisesta epidemiologiasta. Hankkeessa tutkittiin yhdeksää aivotoiminnan häiriötä: dementiaa, depressiota, epilepsiaa, migreeniä, MS-tautia, Parkinsonin tautia, skitsofreniaa, aivoverenkiertohäiriötä ja päihderiippuvuutta. Kunkin häiriön osalta toteutettiin systemaattinen kirjallisuuskatsaus ja fokusryhmähaastattelu. Esiin nousseet psykososiaaliset vaikeudet luokiteltiin ja linkitettiin kansainväliseen toimintakykyluokitukseen (ICF). Eri häiriöille yhteisten 64 psykososiaalisen vaikeuden yleisyyttä ja intensiteettiä tutkittiin yksilöhaastatteluissa (n = 722). Tulosten pohjalta muodostettiin yleisiä psykososiaalisia vaikeuksia mahdollisimman laajasti kattava PARADISE24-kysely. Oletus eri häiriöiden yhteisistä psykososiaalisista ongelmista osoittautui todeksi. Kyselyyn valikoitui neljätoista kysymystä ICF:n osa-alueelta b Ruumiin/kehon toiminnot ja kymmenen kysymystä osa-alueelta d Suoritukset ja osallistuminen. Psykososiaalisten vaikeuksien intensiteetissä esiintyi kuitenkin häiriöiden välillä eroja siten, että psykiatristen tai päihdehäiriöiden takia haastatellut käyttivät laaja-alaisesti viisiportaista vastausvaihtoehtojen asteikkoa, mutta neurologisten häiriöiden yhteydessä kaksi- tai kolmeportainen asteikko vaikutti riittävältä. PARADISE24-kysely sisältää olennaiset kysymykset, mutta jatkotutkimusta tarvitaan erityisesti kyselyn toimivuudesta seurantakäytössä. Raportissa esitetään PARADISE24-kyselyn valmistamisen tutkimusperusta horisontaalisten tulosten sekä erikseen päihdehäiriöiden näkökulmasta.36,00 euro

Asymptotic Dirichlet Problem for A-Harmonic Functions on Manifolds with Pinched Curvature

We study the asymptotic Dirichlet problem for -harmonic functions on a Cartan-Hadamard manifold whose radial sectional curvatures outside a compact set satisfy an upper bound and a pointwise pinching condition for some constants epsilon > 0 and C (K) a 1, where P and are any 2-dimensional subspaces of T (x) M containing the (radial) vector acr(x) and r(x) = d(o, x) is the distance to a fixed point o a M. We solve the asymptotic Dirichlet problem with any continuous boundary data . The results apply also to the Laplacian and p-Laplacian, as special cases.Peer reviewe

System size dependence of nuclear modification and azimuthal anisotropy of jet quenching

We investigate the system size dependence of jet-quenching by analyzing transverse momentum spectra of neutral pions in Au+Au and Cu+Cu collisions at $\sqrt{s_{\textrm{NN}}}$ =200 GeV for different centralities. The fast partons are assumed to lose energy by radiating gluons as they traverse the plasma and undergo multiple collisions. The energy loss per collision, $\epsilon$, is taken as proportional to $E$(where $E$ is the energy of the parton), proportional to $\sqrt{E}$, or a constant depending on whether the formation time of the gluon is less than the mean path, greater than the mean free path but less than the path length, or greater than the path length of the partons, respectively. NLO pQCD is used to evaluate pion production by modifying the fragmentation function to account for the energy loss. We reproduce the nuclear modification factor $R_\textrm{AA}$ by treating $\epsilon$ as the only free parameter, depending on the centrality and the mechanism of energy loss. These values are seen to explain the nuclear modification of prompt photons, caused by the energy lost by final state quarks before they fragment into photons. These also reproduce the azimuthal asymmetry of transverse momentum distribution for pions within a factor of two and for prompt photons in a fair agreement with experimental data.Comment: 26 pages, 17 figures. One more figure added. Discussion expanded. Typographical corrections done, several references added. To appear in Journal of Physics

Nanoparticle formation by ozonolysis of inducible plant volatiles

International audienceWe present the first laboratory experiments of aerosol formation from oxidation of volatile organic species emitted by living plants, a process which for half a century has been known to take place in the atmosphere. We have treated white cabbage plants with methyl jasmonate in order to induce the production of monoterpenes and certain less-volatile sesqui- and homoterpenes. Ozone was introduced into the growth chamber in which the plants were placed, and the subsequent aerosol formation and growth of aerosols were monitored by measuring the particle size distributions continuously during the experiments. Our observations show similar particle formation rates as in the atmosphere but much higher growth rates. The results indicate that the concentrations of nonvolatile oxidation products of plant released precursors needed to induce the nucleation are roughly an order-of-magnitude higher than their concentrations during atmospheric nucleation events. Our results therefore suggest that if oxidized organics are involved in atmospheric nucleation events, their role is to participate in the growth of pre-existing molecular clusters rather than to form such clusters through homogeneous or ion-induced nucleation

Local behavior of p-harmonic Green's functions in metric spaces

We describe the behavior of p-harmonic Green's functions near a singularity in metric measure spaces equipped with a doubling measure and supporting a Poincar\'e inequality

Assessing Precision in Conventional Field Measurements of Individual Tree Attributes

Forest resource information has a hierarchical structure: individual tree attributes are summed at the plot level and then in turn, plot-level estimates are used to derive stand or large-area estimates of forest resources. Due to this hierarchy, it is imperative that individual tree attributes are measured with accuracy and precision. With the widespread use of different measurement tools, it is also important to understand the expected degree of precision associated with these measurements. The most prevalent tree attributes measured in the field are tree species, stem diameter-at-breast-height (dbh), and tree height. For dbh and height, the most commonly used measuring devices are calipers and clinometers, respectively. The aim of our study was to characterize the precision of individual tree dbh and height measurements in boreal forest conditions when using calipers and clinometers. The data consisted of 319 sample trees at a study area in Evo, southern Finland. The sample trees were measured independently by four trained mensurationists. The standard deviation in tree dbh and height measurements was 0.3 cm (1.5%) and 0.5 m (2.9%), respectively. Precision was also assessed by tree species and tree size classes; however, there were no statistically significant differences between the mensurationists for dbh or height measurements. Our study offers insights into the expected precision of tree dbh and height as measured with the most commonly used devices. These results are important when using sample plot data in forest inventory applications, especially now, at a time when new tree attribute measurement techniques based on remote sensing are being developed and compared to the conventional caliper and clinometer measurements.Peer reviewe

The genetic variant rs4073 A→T of the Interleukin-8 promoter region is associated with the earlier onset of exudative age-related macular degeneration

Peer reviewe