ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    facet.materialart.
    Unknown
    A fast feedback controlled magnetic drive for the ASDEX Upgrade fast-ion loss detectors (2016)
    American Institute of Physics (AIP)
    Details
    Publication Date: 2016-08-04
    Description: A magnetically driven fast-ion loss detector system for the ASDEX Upgrade tokamak has been designed and will be presented here. The device is feedback controlled to adapt the detector head position to the heat load and physics requirements. Dynamic simulations have been performed taking into account effects such as friction, coil self-induction, and eddy currents. A real time positioning control algorithm to maximize the detector operational window has been developed. This algorithm considers dynamical behavior and mechanical resistance as well as measured and predicted thermal loads. The mechanical design and real time predictive algorithm presented here may be used for other reciprocating systems.
    Print ISSN: 0034-6748
    Electronic ISSN: 1089-7623
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Published by American Institute of Physics (AIP)
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 2
    facet.materialart.
    Unknown
    Comparison of measured and modelled spectral UV irradiance at Izaña high mountain station: estimation of the underlying effective albedo (2015)
    Wiley
    Details
    Publication Date: 2015-04-28
    Description: ABSTRACT In this work, we have carried out a comparison study between measured and modelled direct and global ultraviolet (UV) (300–400 nm) spectral irradiances and the determination of the surface effective albedo at the high altitude Izaña Observatory [IZO; 2400 m above sea level (a.s.l.)] located in Tenerife (Canary Islands, Spain). The spectral measurements were performed with a Bentham spectroradiometer during the Quality Assurance of Solar Ultraviolet Spectral Irradiance Measurements (QASUME) comparison campaign in June 2005. The simulations were obtained with the LibRadtran radiative transfer model. The model input parameters, such as total ozone and aerosol optical depth (AOD), were measured at IZO. The comparison between measured and modelled direct solar radiation component was made at 0.5 nm spectral resolution, showing excellent agreement, with differences below 5% for solar zenith angle (SZA) 〈 60°. These differences were attributed to the effect of the underlying surface albedo due to the frequent existence of a sea of clouds below the station altitude. The underlying surface albedo was determined using different methods. In spite of the variability of this parameter through the day due to the strong influence and variable structure of these underlying clouds, the mean of this effective surface albedo in the UV region gives a value between 0.2 and 0.5 in the UV range, 10 times higher than the local surface albedo (0.02–0.05).
    Print ISSN: 0899-8418
    Electronic ISSN: 1097-0088
    Topics: Geosciences , Physics
    Published by Wiley
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 3
    facet.materialart.
    Unknown
    Understanding the dynamic magnetization process for the magnetoelectric effect in multiferroic composites (2016)
    American Institute of Physics (AIP)
    Details
    Publication Date: 2016-04-01
    Description: Based on a magnetic relaxation model, an approach that includes the spin dynamics is proposed and applied to describe the magnetoelectric (ME) effect frequency dependence for a 0–3 type composite at low temperatures. Our results show that the ME coefficient, in low temperatures, for PMN-PT/CFO ( ( 1 − x ) P b ( M g 1 / 3 N b 2 / 3 ) − x P b T i O 3 / C o F e 2 O 4 ) composite has a step-like behavior on the hysteresis loop for frequency of 1 kHz, contrasting with the results at low frequencies (10 Hz). This approach assumes that the ferromagnetic and ferroelectric phases are coupled through the interactions of the spins of the ferromagnetic phase with the composite phonons by spin/lattice relaxation.
    Print ISSN: 0021-8979
    Electronic ISSN: 1089-7550
    Topics: Physics
    Published by American Institute of Physics (AIP)
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 4
    facet.materialart.
    Unknown
    Endorheic‐exorheic transitions of the Rio Grande and East African rifts (2019)
    Wiley
    Details
    Publication Date: 2019
    Description: Abstract Tectonic extension of continental lithosphere creates accommodation space in which sediments are deposited. Climate‐driven processes provide the mechanism by which mass is detached from hillslopes and sediments are transported into this accommodation space. These two forcings, climate and tectonics, act together to create either endorheic (internally drained) or exorheic (externally drained) rift basins. Here we use a large‐scale dynamic landscape evolution‐tectonics model to understand the contribution of tectonic processes in endorheic‐exorheic transitions. In the model, extension results in opening of an asymmetric half‐graben along a listric normal fault. Rift opening occurs in the models in wet, temperate, or semi‐arid climates where runoff and evapotranspiration are varied. Our numerical experiments show that slow rift‐opening rates, a slowing‐down of rift opening, or increase of headwater topography (e.g., upstream epeirogenic uplift), are tectonic situations that can cause a transition from an endorheic to an exorheic drainage state in a rift basin. Our results also show that wet climate conditions lead to a permanent exorheism that persists regardless of rift opening rates. In semi‐arid climates, endorheic conditions are favored, and may last for the duration of rifting except for when rift opening is very slow. These results form an interpretive framework to study endorheic and exorheic drainage systems in natural continental rifts. In the slow‐opening Rio Grande rift, the endorheic‐exorheic transition may have occurred without dramatic climate changes. Lake‐level variations in East African rift basins are predicted by our models to result from variations in climate.
    Electronic ISSN: 1525-2027
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 5
    facet.materialart.
    Unknown
    Performance evaluation of two high shear impellers in an unbaffled stirred tank (2015)
    Wiley
    Details
    Publication Date: 2015-06-20
    Description: High shear impellers (HSIs) are mixers used in industrial stirred tanks to incorporate powders into liquid and break down particle agglomerates. In this work, a detail numerical study of two commercial ring-style HSIs of laboratory scale (Hockmeyer® Equipment Corp. D-Blade of two and four rings) was carried out at 50≤ Re ≤75, and their performance was compared with the Rushton Turbine (RT). It was found that power and pumping numbers or their ratio, cannot be simply connected for selecting properly an impeller in applications where highly localized viscous dissipation is desirable. The ratio of the average viscous dissipation in the impeller swept volume, , to the mean in the entire volume, , at two constant values of power input, P , was found to be lower for HSIs to that evaluated for RT. However, when P increases from 4.25 to 12.92 W , the dimensionless average viscous dissipation in the blade swept volume, at the higher P was found to be similar for the HSI of two rings and the RT, corroborating the high local viscous dissipation of this HSI when operated at higher speeds.
    Print ISSN: 0930-7516
    Electronic ISSN: 1521-4125
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Published by Wiley
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 6
    facet.materialart.
    Unknown
    Solar radiation measurements compared to simulations at the BSRN Izaña station. Mineral dust radiative forcing and efficiency study (2013)
    Wiley
    Details
    Publication Date: 2013-12-07
    Description: [1]  This paper presents a comparative study of shortwave downward radiation (SDR) measurements and simulations, obtained with the radiative transfer model (RTM) LibRadtran, at the Baseline Surface Radiation Network (BSRN) site of Izaña Atmospheric Observatory (IZA, Spain). The analysis is based on cloud-free days between March 2009 and August 2012 (386 days), including aerosol-free and Saharan mostly pure mineral dust conditions and comparing the day-to-day, annual and inter-annual variability.The observed agreement between simulations and measurements is excellent: the variance of daily measurements overall agrees within 99% with the variance of daily simulations and the mean bias (simulations - measurements) is -0.30 ± 0.24 MJm -2 (-1.1 ± 0.9%) for global, -0.16 ± 0.34 MJm -2 (-0.4 ± 0.9%) for direct and +0.02 ± 0.25 MJm -2 (+0.9 ± 9.2%) for diffuse SDR. Furthermore, the diurnally averaged aerosol radiative forcing ( Δ DF) and radiative forcing efficiency ( ΔDF eff ) due to Saharan mostly pure mineral dust events has been computed at Izaña Observatory. The mean Δ DF values are -7 ± 1, -96 ± 5 and 44 ± 2 Wm -2 for global, direct and diffuse BSRN SDR,respectively (mean aerosol optical depth, AOD, at 500 nm of 0.18 ± 0.01), while the mean ΔDF eff values are -59 ± 6, -495 ± 11 and 230 ± 8 Wm -2 per unit of AOD at 500 nm for global, direct and diffuse BSRN SDR, respectively. These values highlight the importance of scattering processes for mineral dust aerosols: the ratio between Δ DF and the corresponding SDR without aerosols is ~ 2.5% for diffuse SDR versus 0.2% for direct SDR. This illustrates the significant potential of mineral dust particles to cool the Earth-atmosphere system.
    Print ISSN: 0148-0227
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 7
    facet.materialart.
    Unknown
    Decoupled crust-mantle accommodation of Africa-Eurasia convergence in the NW Moroccan margin (2011)
    Wiley
    Details
    Publication Date: 2011-08-16
    Description: The extent of the area accommodating convergence between the African and Iberian plates, how this convergence is partitioned between crust and mantle, and the role of the plate boundary in accommodating deformation are not well-understood subjects. We calculate the structure of the lithosphere derived from its density distribution along a profile running from the Tagus Abyssal Plain to the Sahara Platform and crossing the Gorringe Bank, the NW Moroccan margin, and the Atlas Mountains. The model is based on the integration of gravity, geoid, elevation, and heat flow data and on the crustal structure across the NW Moroccan margin derived from reflection and wide-angle seismic data. The resulting mantle density anomalies suggest important variations of the lithosphere-asthenosphere boundary (LAB) topography, indicating prominent lithospheric mantle thickening beneath the margin (LAB 〉 200 km depth) followed by thinning beneath the Atlas Mountains (LAB ∼90 km depth). At crustal levels the Iberia-Africa convergence is sparsely accommodated in a ∼950 km wide area and localized in the Atlas and Gorringe regions, with an inferred shortening of ∼50 km. In contrast, mantle thickening accommodates a 400 km wide region, thus advocating for a decoupled crustal-mantle mechanical response. A combination of mantle underthrusting due to oblique convergence, together with a viscous dripping fed by lateral mantle dragging, can explain the imaged lithospheric structure. The model is consistent with crustal shortening estimates and with the accommodation of part of the Iberia-Africa convergence farther NW of the Gorringe Bank and/or off the strike of the profile.
    Print ISSN: 0148-0227
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 8
    facet.materialart.
    Unknown
    High strain in polycrystalline Ni48.8Mn31.4Ga19.8 Heusler alloys under overlapped static and oscillating magnetic fields (2014)
    American Institute of Physics (AIP)
    Details
    Publication Date: 2014-09-18
    Description: Martensitic polycrystalline Ni 48.8 Mn 31.4 Ga 19.8 Heusler alloys, with a stacking period of 14 atomic planes at room temperature, were innovatively processed by combining high-energy ball milling and powder metallurgy. Bulk samples were mechanically coupled to a piezoelectric material in a parallel configuration, and the mechanical deformation of the studied system due to the twin's variant motion was investigated under overlapped static and oscillating magnetic fields. A reversible and high mechanical deformation is observed when the frequency of the oscillating magnetic field is tuned with the natural vibration frequency of this system. In this condition, a linear deformation as a function of the static magnetic field amplitude occurs in the ±4 kOe range, and a mechanical deformation of 2% at 10 kOe is observed.
    Print ISSN: 0021-8979
    Electronic ISSN: 1089-7550
    Topics: Physics
    Published by American Institute of Physics (AIP)
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 9
    facet.materialart.
    Unknown
    Infinitesimal Legendre symmetry in the Geometrothermodynamics programme (2014)
    American Institute of Physics (AIP)
    Details
    Publication Date: 2014-08-14
    Description: The work within the Geometrothermodynamics programme rests upon the metric structure for the thermodynamic phase-space. Such structure exhibits discrete Legendre symmetry. In this work, we study the class of metrics which are invariant along the infinitesimal generators of Legendre transformations. We solve the Legendre-Killing equation for a K -contact general metric. We consider the case with two thermodynamic degrees of freedom, i.e., when the dimension of the thermodynamic phase-space is five. For the generic form of contact metrics, the solution of the Legendre-Killing system is unique, with the sole restriction that the only independent metric function – Ω – should be dragged along the orbits of the Legendre generator. We revisit the ideal gas in the light of this class of metrics. Imposing the vanishing of the scalar curvature for this system results in a further differential equation for the metric function Ω which is not compatible with the Legendre invariance constraint. This result does not allow us to use Quevedo's interpretation of the curvature scalar as a measure of thermodynamic interaction for this particular class.
    Print ISSN: 0022-2488
    Electronic ISSN: 1089-7658
    Topics: Mathematics , Physics
    Published by American Institute of Physics (AIP)
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 10
    facet.materialart.
    Unknown
    CFD study of the flow induced by a grooved high-shear impeller in an unbaffled tank (2017)
    Wiley
    Details
    Publication Date: 2017-12-16
    Description: A detailed hydrodynamic characterization in the transitional flow regime (20≤ Re ≤133) of two variants of the Norstone Polyblade® high-shear impeller (HSI), of industrial relevance, is presented. The study was carried out on a simulated Newtonian fluid using computational fluid dynamics (CFD). Measurements of power number were carried out in order to validate the simulation results. Hydrodynamic parameters considered of key importance in powder dispersion processes ( i.e. viscous dissipation and effective circulation), were used to assess the impellers’ performance. Furthermore, their performances were compared with reported data for two ring-style HSIs of two and four rings, and power number measurements of a sawtooth (Cowles type) impeller. The results show that both NR-type and Cowles impellers exhibit lower power number values, i.e. , they consume less power at a given Reynolds number than the two ring-style HSIs. In addition, it was found that at the same power input, the Norstone impellers induce higher maximum values of viscous dissipation than the two ring-style HSIs and suitable effective circulation, what in principle, makes them better suited for mixing dispersion processes.
    Print ISSN: 0930-7516
    Electronic ISSN: 1521-4125
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Published by Wiley
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...