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
    Investigation on fluid added mass effect in the modal response of a pump-turbine runner (2013)
    Institute of Physics (IOP)
    Details
    Publication Date: 2013-12-22
    Description: With the improvement of technology and manufacturing level of hydraulic turbine, there is a trend to increase the power concentration of the units. As a consequence, heads, fluid velocities and rotational speeds are higher which lead to larger hydraulic excitation forces on the structures. Accordingly, vibration and high stress levels will arise, which may cause fatigue damage. Therefore, how to predict the natural frequencies and mode shapes of the runner during the design stage is of paramount importance. In this paper, numerical simulation to analyze the influence of the surrounding water in a pump-turbine runner modal has been carried out by using finite element method. The modal behavior of the runner in air and in water has been calculated. In addition, the added mass effect by comparing the natural frequencies and mode shapes in both cases has been determined. The results show that, due to the added mass effect of the surrounding water, natural frequencies are considerabl...
    Print ISSN: 1757-8981
    Electronic ISSN: 1757-899X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Published by Institute of Physics (IOP)
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 2
    facet.materialart.
    Unknown
    Dryland Climate Change: Recent Progress and Challenges (2017)
    Wiley
    Details
    Publication Date: 2017-07-21
    Description: Drylands are home to more than 38% of the world's population and are one of the most sensitive areas to climate change and human activities. This review describes recent progress in dryland climate change research. Recent findings indicate that the long-term trend of the aridity index (AI) is mainly attributable to increased greenhouse gas emissions while anthropogenic aerosols exert small effects but alter its attributions. Atmosphere-land interactions determine the intensity of regional response. The largest warming during the last 100 years was observed over drylands and accounted for more than half of the continental warming. The global pattern and inter-decadal variability of aridity changes are modulated by oceanic oscillations. The different phases of those oceanic oscillations induce significant changes in land-sea and north-south thermal contrasts, which affect the intensity of the westerlies and planetary waves and the blocking frequency, thereby altering global changes in temperature and precipitation. During 1948-2008, the drylands in the Americas became wetter due to enhanced westerlies, whereas the drylands in the Eastern Hemisphere became drier because of the weakened East Asian summer monsoon. Drylands as defined by the AI have expanded over the last sixty years and are projected to expand in the 21 st century. The largest expansion of drylands has occurred in semi-arid regions since the early 1960s. Dryland expansion will lead to reduced carbon sequestration and enhanced regional warming. The increasing aridity, enhanced warming and rapidly growing population will exacerbate the risk of land degradation and desertification in the near future in developing countries.
    Print ISSN: 8755-1209
    Topics: Geosciences
    Published by Wiley on behalf of American Geophysical Union (AGU).
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 3
    facet.materialart.
    Unknown
    First results from the Cornell high Q cw full linac cryo- module (2015)
    Institute of Physics (IOP)
    Details
    Publication Date: 2015-12-19
    Description: Cornell University has finished building a 10 m long superconducting accelerator module as a prototype of the main linac of a proposed ERL facility. This module houses 6 superconducting cavities- operated at 1.8 K in continuous wave (CW) mode - with individual HOM absorbers and one magnet/ BPM section. In pushing the limits, a high quality factor of the cavities (2•10 10 ) and high beam currents (100 mA accelerated plus 100 mA decelerated) were targeted. The design of the cryomodule and the results of components tested before assembly will be presented in this paper.
    Print ISSN: 1757-8981
    Electronic ISSN: 1757-899X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Published by Institute of Physics (IOP)
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 4
    facet.materialart.
    Unknown
    Black carbon measurements in the Pearl River Delta region of China (2011)
    Wiley
    Details
    Publication Date: 2011-06-28
    Description: The Pearl River Delta (PRD) region in southeastern China is one of the most polluted industrial and metropolitan areas in the world. We report single-particle measurements of the refractory black carbon (rBC) component in ambient aerosol in the region, and we interpret the results to improve understanding of the importance of rBC for radiative forcing in this region and others like it. A Single-Particle Soot Photometer (SP2) provided rBC mass loadings, size distributions, and mixing state information. Average rBC loadings are approximately an order of magnitude higher than those measured near Houston, Texas, a major U.S. metropolitan area. The rBC in the PRD is also more often internally mixed with nonrefractory materials than is rBC around Houston. Localized atmospheric heating from rBC solar absorption reached an average rate of 0.4 K d−1. A one-dimensional discrete ordinates radiative transfer (DISORT) model coupled with the average measured rBC is used to illustrate the potential local contribution of rBC mass and associated scattering aerosol to the radiative forcing. Solar energy deposition rates in the atmosphere at the sampling site due to rBC absorption are estimated to have an average value of 17 W m−2 and be largest in the first 1 km above the ground. These results indicate that rBC has significant potential to influence local meteorology and climate parameters in the PRD region.
    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
  • 5
    facet.materialart.
    Unknown
    Influence of the angle between cold rolling direction and hot rolling direction on the texture evolution of non-oriented electrical steels (2015)
    Institute of Physics (IOP)
    Details
    Publication Date: 2015-04-26
    Description: In processing non-oriented electrical steel sheets using conventional rolling schemes, the most common texture components obtained after final annealing are the magnetically unfavourable //ND (?) and //RD (?) fibres. A lot of researches have been carried out trying to optimize the processes to produce the favourable //ND (?) fibre. However, since the final texture is formed through a series of texture evolution steps during the solidification, hot rolling, cold rolling and annealing processes, it is quite challenging to tailor the texture of the final product. In this study, a new rolling scheme was examined, in which the cold rolling direction (CRD) was inclined to the hot rolling direction (HRD) at an angle from 0? to 90? (with a 15? increment). This was intended to alter the texture commonly produced by cold rolling along the HRD, and to optimize the final recrystallization texture. The cold rolling and recrystallization textures of two non-ori...
    Print ISSN: 1757-8981
    Electronic ISSN: 1757-899X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Published by Institute of Physics (IOP)
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 6
    facet.materialart.
    Unknown
    The energy saving research of the flat tire vulcanization process (2015)
    Institute of Physics (IOP)
    Details
    Publication Date: 2015-07-17
    Description: Vulcanization was an important step in tire production process, directly determining the mechanical properties of the tire which was the most energy-intensive link. The traditional vulcanization process of a flat tire did not consider the post curing effect, which may result in a waste of energy. Early finite element simulation showed that the traditional process caused excessive vulcanization. In order to find ways to improve the curing process, in the paper effect of process parameters on the flat tire vulcanization had been studied. Curing parameters included heating temperature, curing time and preheating temperature. Corresponding to these three factors, the three-dimensional model was established by ABAQUS finite element software to carry out three groups of simulation. Result showed that heat source temperature on the maximum temperature was the largest, effect of preheating temperature was the lowest; heat source temperature on the curing degree was the largest, effect of...
    Print ISSN: 1757-8981
    Electronic ISSN: 1757-899X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Published by Institute of Physics (IOP)
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 7
    facet.materialart.
    Unknown
    Early Palaeozoic high-pressure granulites from the Dunhuang block, northeastern Tarim Craton: constraints on continental collision in the southern Central Asian Orogenic Belt (2012)
    Wiley
    Details
    Publication Date: 2012-07-14
    Description: The Central Asian Orogenic Belt (CAOB) is one of the largest accretionary collages in the world, and records a prolonged sequence of subduction-accretion and collision processes. The Tarim Craton is located at the southernmost margin of the CAOB. In this study, the discovery of early Palaeozoic high-pressure (HP) granulites from the Dunhuang block in the northeastern Tarim Craton is reported, and these rocks are characterized through detailed petrological and geochronological studies. The peak mineral assemblage of the HP mafic granulite is garnet + clinopyroxene + plagioclase + quartz + rutile, which is overprinted by amphibolite facies retrograde metamorphic assemblages. The calculated P–T conditions of the peak metamorphism are ∼1.4–1.7 GPa and ∼800 °C. The retrograde P–T conditions are ∼0.7 GPa and ∼700 °C. The metamorphic zircon grains from the HP mafic granulite show homogeneous CL-images, low Th/U ratios and flat HREE patterns and yield a weighted mean 206 Pb/ 238 U age of 444 ± 5 Ma. The metamorphic zircon grains from the associated kyanite-bearing garnet gneiss and garnet-mica schist show a similar 206 Pb/ 238 U age of 429 ± 3 and 435 ± 4 Ma, respectively. The c. 440–430 Ma age is interpreted to mark the timing of HP granulite facies metamorphism in the Dunhuang block. The results from this study suggest that the Dunhuang block experienced continental subduction prior to the early Palaeozoic collisional orogeny between the northeastern Tarim Craton and the southern CAOB, and the Dunhuang area could be considered as the southward extension of the CAOB. It is suggested that the continental collision in the eastern part involving the Dunhuang block of the southern CAOB may have occurred c. 120 Ma earlier than in the western part involving the Tianshan orogen.
    Print ISSN: 0263-4929
    Electronic ISSN: 1525-1314
    Topics: Geosciences
    Published by Wiley
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 8
    facet.materialart.
    Unknown
    Comparing satellite derived precipitation datasets using the Hillslope River Routing (HRR) model in the Congo River Basin (2011)
    Wiley
    Details
    Publication Date: 2011-02-10
    Description: In this paper, three satellite derived precipitation datasets (TRMM, CMORPH, PERSIANN) are used to drive the Hillslope River Routing (HRR) model in the Congo Basin. The precipitation data are compared spatially and temporally in two forms: (1) precipitation magnitudes and (2) resulting streamflow and water storages. Simulated streamflow is assessed using historical monthly discharge data from in-situ stream gauges and recent stage data based on water surface elevations derived from ENVISAT radar altimetry data. Simulated total water storage is assessed using monthly storage change values derived from GRACE data. The results show that the three precipitation datasets vary significantly in terms of magnitudes but generally produce a reasonable hydrograph throughout much of the basin, with the exception of the equatorial regions of the watershed. The satellite datasets provide unreasonably high values for specific periods (e.g., all three in Oct-Nov; only CMORPH and PERSIANN in Mar-Apr) in the equatorial regions. Overall, TRMM (3B42) provides the best spatial and temporal distributions and magnitudes or rainfall based on the assessment measures used here. Both CMORPH and PERSIANN tend to overestimate magnitudes, especially in the equatorial regions of the Basin. Copyright © 2011 John Wiley & Sons, Ltd.
    Print ISSN: 0885-6087
    Electronic ISSN: 1099-1085
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Published by Wiley
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 9
    facet.materialart.
    Unknown
    In Situ Measurement of the Toughness of the Interface Between a Thermal Barrier Coating and a Ni Alloy (2011)
    Wiley
    Details
    Publication Date: 2011-05-21
    Description: A flexural test for the in situ measurement of the delamination toughness of the interface between a thermally grown oxide and a bond coat in the presence of a thermal barrier coating (TBC) has been implemented. To accomplish the testing, a section of the substrate was removed by microelectro-discharge machining and a precrack introduced through the TBC by center point loading. This was followed by application of an asymmetric single-point load to extend a delamination along the interface. A displacement and strain mapping method was used to locate the delamination and to ascertain its extension. To relate the energy release rate and mode mixity to the crack extension and the loads, a finite-element method was implemented. The ensuing fracture resistance was found to vary along the interface with values in the range of 25–95 J/m 2 .
    Print ISSN: 0002-7820
    Electronic ISSN: 1551-2916
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Published by Wiley
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 10
    facet.materialart.
    Unknown
    Magnitudes and drivers of greenhouse gas fluxes in floodplain ponds during drawdown and inundation by the Three Gorges Reservoir (2019)
    Wiley
    Details
    Publication Date: 2019
    Description: Abstract Hydropower reservoirs are well‐known emitters of greenhouse gases to the atmosphere. This is due in part to seasonal water level fluctuations that transfer terrestrial C and N from floodplains to reservoirs. Partial pressures and fluxes of the greenhouse gases CH4, CO2, and N2O are also a function of in‐situ biological C and N cycling and overall ecosystem metabolism, which varies on a diel basis within inland waters. Thus, greenhouse gas emissions in hydropower reservoirs likely vary over seasonal and diel timescales with local hydrology and ecosystem metabolism. China's Three Gorges Reservoir is among the largest and newest in the world, with a floodplain that encompasses approximately one third of the reservoir area. We measured diel partial pressures and fluxes of greenhouse gases in ponds on the Three Gorges Floodplain. We repeated these measurements on the submerged floodplain following inundation by the Three Gorges Reservoir. During reservoir drawdown, CH4 ebullition comprised 60‐68% of emissions from floodplain ponds to the atmosphere. Using linear mixed effects modeling, we show that partial pressures of CH4 and CO2 and diffusive CO2 fluxes in floodplain ponds varied on a diel basis with in‐situ respiration. Floodplain inundation by the Three Gorges Reservoir significantly moderated areal CH4 diffusion and ebullition. Diel pCO2, pCH4, pN2O, and diffusive fluxes of CO2 on the submerged floodplain were also driven by in‐situ respiration. The drawdown/inundation cycle of the Three Gorges Reservoir therefore changes the magnitudes of aquatic greenhouse gas fluxes on its floodplain.
    Print ISSN: 2169-8953
    Electronic ISSN: 2169-8961
    Topics: Biology , Geosciences
    Published by Wiley on behalf of American Geophysical Union (AGU).
    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...