In this study, an improvement method for double-fed asynchronous motor-generators (DFAMG) design with open slots is proposed to reduce the capacity demand of rotor converter for the first time. The ...proposed method is achieved by decreasing the air-gap length (AGL) and applying conductive and magnetic rotor slot wedges. The design method of magnetic slot wedges and AGL in large DFAMG is presented. The mechanical analysis of a large DFAMG prototype reveals the necessity of using metal rotor wedges. To precisely investigate the influence of magnetic wedges in DFAMG, a two-dimensional field-circuit coupled model is proposed to consider the effects of rotor converter. Several wedge configurations of commercially available products are designed and analysed. The relationships between the electromagnetic properties of rotor wedges and prototype performance are investigated. The feasibility and advantage of the proposed method in DFAMG design are verified. A guidance for applying the proposed method in design improvement of large DFAMG is developed.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
In protein microcrystallography, radiation damage often hampers complete and high‐resolution data collection from a single crystal, even under cryogenic conditions. One promising solution is to ...collect small wedges of data (5–10°) separately from multiple crystals. The data from these crystals can then be merged into a complete reflection‐intensity set. However, data processing of multiple small‐wedge data sets is challenging. Here, a new open‐source data‐processing pipeline, KAMO, which utilizes existing programs, including the XDS and CCP4 packages, has been developed to automate whole data‐processing tasks in the case of multiple small‐wedge data sets. Firstly, KAMO processes individual data sets and collates those indexed with equivalent unit‐cell parameters. The space group is then chosen and any indexing ambiguity is resolved. Finally, clustering is performed, followed by merging with outlier rejections, and a report is subsequently created. Using synthetic and several real‐world data sets collected from hundreds of crystals, it was demonstrated that merged structure‐factor amplitudes can be obtained in a largely automated manner using KAMO, which greatly facilitated the structure analyses of challenging targets that only produced microcrystals.
An automated data‐processing pipeline for protein microcrystals is presented. The processing of multiple small‐wedge data sets was made dramatically easier by this pipeline.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
•New petrologic-geochemical data on granitoïds of the Songpan Ganze terrane (E Tibet).•Magmatism and tectonics of the Songpan Ganze orogenic wedge.•A geodynamic model for concomitant high-K and ...peraluminous magmatism during orogeny.•Paleotethys closure, tectonic accretion, slab retreat and asthenospheric upwelling.•Slab retreat, tear faulting, and magmatism along the Yangtze former passive margin.
The eastern Songpan Ganze accretionary-orogenic wedge (northern Tibetan plateau) is characterized by extensive magmatism coeval with Middle to Upper Triassic closure of the Paleotethys Ocean along a double subduction system, traced by the Kunlun-Anyemaqen suture to the north and the Jinsha-Litang suture to the south. New field, petrographic and geochemical data on Mesozoic plutons intrusive into Triassic metasediments of the eastern Songpan Ganze wedge are presented and integrated in a review of available data for the region. Three types of granitoids are distinguished: (i) high-K calc-alkaline granite to granodiorite (Yanggon, Maoergai, Markam, Sheng Meng, Xue Sheng, Taiyanghe, Menggu, Manai, Dusong Xian, Tagong and Jiulong plutons), (ii) high-K alkaline granite (Nyanbaoyeche and Rilong plutons and the Niuxingou shoshonitic syenite), and (iii) peraluminous S-type granite (Markam and Manai leucogranites). Elemental and isotopic signatures of these granitoids are consistent with the implication of both crustal (Yangtze craton, and Songpan Ganze metasediments) and mantle (asthenospheric mantle and metasomatised lithospheric mantle) sources. Based on (i) the ages of the plutons that are concomitant with the end of the northern and southern subductions of the Paleo-Tethys, (ii) the position of the plutons intrusive in the crustal tectonically accreted units decoupled from the downgoing plate of this double subduction system, (iii) the diversity of their petrological and geochemical signatures, we propose that magma emplaced in the Songpan Ganze accretionary-orogenic wedge were generated at the end of the Paleotethys closure in a context of slab retreat, accommodated by a tear fault along the passive margin of the South China block. Indeed, we argue that this context is the most favourable to trigger synchronous partial melting of (i) the suprasubduction enriched mantle wedge owing to lowering of the mantle solidus by metasomatism, (ii) the upwelled undepleted asthenospheric mantle into the tear fault owing to decompression, (iii) the metasomatized lithospheric continental mantle of the Yangtze craton owing to the temperature increase associated to the asthenospheric upwelling and (iv) the rocks of the Songpan Ganze accretionary wedge composed of metasediments and Yangtze continental margin basement owing to the combined effects of increased radioactive heat production and mantle heat flux. We propose that the concentration of plutons along the eastern margin of the Songpan Ganze results from focussed migration and emplacement of the granitic magmas guided by the development of a tear fault along the former passive eastern margin of the Yangtze craton as a consequence of the Paleotethys slab retreat.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The present study investigates dipolarization signatures in the inner magnetosphere using sharp geosynchronous dipolarizations as a reference. The results are summarized as follows: (1) The region of ...sharp and structured dipolarizations expands earthward while dipolarizations are sustained at geosynchronous orbit; (2) within 5 RE from Earth, dipolarization signatures are often smooth and gradual, resembling midlatitude positive bays, and they start simultaneously with substorm onsets; (3) off the equator (>0.5 RE), sharp dipolarizations often take place before geosynchronous dipolarizations. These results can be explained by a model current system with R1‐sense and R2‐sense current wedges (R1CW and R2CW) if (a) the R1CW, which is located outside, is more intense than the R2CW in total current, (b) the R1CW stays outside of geosynchronous orbit, and (c) the R2CW moves earthward. The model suggests that the region of sharp dipolarizations is confined between the two current wedges, and it expands earthward as the R2CW moves earthward (Result 1). Sufficiently earthward of the R2CW, the remote effect of the R1CW dominates that of the R2CW, and accordingly, magnetic disturbances resemble midlatitude positive bays (Result 2). Since the timing of sharp dipolarizations is determined by the passage of the R2CW, they take place earlier for outer flux tubes. Away from the magnetic equator, sharp dipolarizations can precede geosynchronous dipolarizations especially if the magnetic configuration is stretched (Result 3). Thus, this double‐current wedge model explains the variability of dipolarization signatures at different distances, and it may be regarded as a generalized substorm current wedge model.
Key Points
The region of sharp dipolarizations expands earthward in the inner magnetosphere while geosynchronous dipolarizations are sustained
Dipolarizations at r < 5 Re are often smooth and gradual resembling midlatitude positive bays, and start simultaneously with substorm onsets
In the inner magnetosphere, sharp dipolarizations start earlier off the equator, often before geosynchronous dipolarizations
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The mechanics and dynamics of thin‐skinned compressible thrust wedges with prescribed offsets in the backstop, i.e., transfer zones, are investigated using a three‐dimensional finite difference ...numerical model with a visco‐brittle/plastic rheology. The main questions addressed are as follows: (i) What is the influence of the initial length of the backstop offset and (ii) what is the effect of the frictional strength of the main décollement on the structural evolution of the brittle wedges along such transfer zones? Results show that the shorter the backstop offset, the earlier these two thrust planes connect, forming a curved frontal thrust along the entire width of the model. Younger, in‐sequence thrusts are formed parallel to this curved shape. Long backstop offsets produce strongly curved thrust faults around the indenting corner. Simulations with a weak basal friction evolve toward almost linear frontal thrusts orthogonal to the bulk shortening direction. Increased basal drag in models with a strong décollement favors propagation of the backstop offset into a transfer zone up to the frontal thrust. These simulations revealed that surface tapers of the wedge in front of the backstop promontory are larger than what the critical wedge theory predicts, whereas the tapers on the other side of the transfer zone are smaller than analytical values. This difference is amplified with increasing length of the backstop offset and/or strength of the décollement. Modeled surface elevation schemes reproduce well the topographic patterns of natural orogenic systems such as the topographic low along the Minab‐Zendan transform/transfer fault between the Zagros and Makran.
Key Points
High‐resolution numerical modelling of thin‐skinned wedgesStructural evolution of critical wedges along a transfer zoneComparison to the Zagros‐Makran transition zone
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This paper presents a deep learning algorithm for tomographic reconstruction (GANrec). The algorithm uses a generative adversarial network (GAN) to solve the inverse of the Radon transform directly. ...It works for independent sinograms without additional training steps. The GAN has been developed to fit the input sinogram with the model sinogram generated from the predicted reconstruction. Good quality reconstructions can be obtained during the minimization of the fitting errors. The reconstruction is a self‐training procedure based on the physics model, instead of on training data. The algorithm showed significant improvements in the reconstruction accuracy, especially for missing‐wedge tomography acquired at less than 180° rotational range. It was also validated by reconstructing a missing‐wedge X‐ray ptychographic tomography (PXCT) data set of a macroporous zeolite particle, for which only 51 projections over 70° could be collected. The GANrec recovered the 3D pore structure with reasonable quality for further analysis. This reconstruction concept can work universally for most of the ill‐posed inverse problems if the forward model is well defined, such as phase retrieval of in‐line phase‐contrast imaging.
A generative adversarial network (GAN) is used to reconstruct the missing‐wedge tomographic data of an in situ ptychographic measurement.
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•Unsteady Falkner-Skan flow of Carraeu nanofluid over a wedge is modeled.•Melting heat transfer is considered.•Brownian motion and thermophoresis are accounted.•Heat generation/absorption is ...incorporated.•Zero nanoparticle mass flux condition is implemented.
This article focuses on the numerical investigation of the melting and heat generation/absorption phenomena in unsteady Falkner-Skan wedge flow of Carreau nanofluid. A zero nanoparticle mass flux condition at the boundary is implemented. Flow is induced due to stretched surface in the presence of the Brownian motion and thermophoresis effects. Suitable transformations are utilized to attain non-linear ordinary differential equations. The resulting non-linear ordinary differential equations are then solved numerically through bvp4c Matlab package. Effects of several emerging parameters on the temperature and nanoparticles concentration profiles are explored and discussed. The reduced Nusselt number is also calculated and examined. A comparison is presented between the current results and available data and found to be in outstanding agreement. Our study predicts that the temperature and nanoparticles concentration profiles depreciate by enhancing values of the melting parameter both for shear thinning and shear thickening fluids.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Tapered elastic wedges can be used to control flexural vibrations and this article explores a method of enhancing the performance of such terminations using multiple wedges. A system design where a ...uniform beam is terminated by multiple quadratically tapered wedges of different lengths is proposed, aiming to enhance the absorption of flexural vibrations. An analytical method based on the exact solution of the non-uniform one-dimensional Euler–Bernoulli beam is used to analyse this system, with the additional assumptions that the moments and forces at the junction from the side of the beam are balanced by the sums of the moments and forces of the wedges. The analytical model is compared with Finite Element simulations and its range of validity is discussed. Differences arise between the analytical and numerical results due to torsional effects, however, it is shown that a trident-shaped configuration can be used to suppress the effect of torsion. Simulations using the analytical model show that for the proposed multiple-wedge termination, more frequency bands of very low reflection, and thus very high absorption, appear compared to single-wedge terminations. Such bands of low reflection also occur at lower frequencies, where the absorptive capability of a single wedge is limited. An analysis of the zeros of the reflection coefficient in the complex-frequency plane is used to investigate the enhanced absorption through the concept of critical coupling. This analysis shows that the multiple-wedge termination leads to richer modal content due to the modal coupling between the wedges of different lengths, and that for appropriate length combinations very little damping can give very high absorption at certain frequencies. The proposed design thus provides significant enhancement of absorptive behaviour compared to a single-wedge termination.
•Multiple-wedge terminations to a beam provide a new mechanism for enhanced absorption.•More bands of low reflection appear, also at lower frequencies.•Tuning the wedge lengths and damping can give low reflection at desired frequencies.•Zero reflection at certain frequencies is possible with very little damping.•Analysis of complex-frequency zeros of the reflection coefficient facilitates design.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Polygenetic soils developed in extraglacial areas.•Deep sediment decalcification during the Eemian Interglacial.•Resumption of the pedological clock in the Vistulian.•Sand-wedge casts play the role ...of geochemical corridors.
Three soil profiles at the Koczery site (E Poland), studied through soil and sediment evaluation, reveal a polygenetic development of soils in areas unglaciated during the Weichselian glaciation (MIS 2) period. Pedogenesis had developed on glacial till (till) in period from the Saalian glaciation (MIS 6) to the Holocene (MIS 1). Wide-spectrum analyses demonstrate that the profiles represent a Planosol. Four stages (I–IV) of soil formation were distinguished in the study area. Stage I, comprising of a nutrient- and element-rich material, correlates to the accumulation of Saalian glacial till (MIS 6). Stage II, that took place during the Eemian Interglacial (MIS 5e), corresponds to the initial development of Cambisol as a result of carbonate leaching process. This was followed by the development of a Luvisol through the processes of illuviation of clay minerals and iron components. Stage III bears evidence of intensive frost weathering processes along with a development of sand-wedge cast that occurred under permafrost conditions of Weichselian glaciation (MIS 2). Further, the formation of an aeolian pavement along with erosion and removal of upper portions of the Eemian soil took place. An accumulation of coeval-age coversand led to a restart of the pedological clock, which resulted in the development of cryogenically-altered soils. Stage IV ushered the Holocene (MIS 1) delivering a progressive development of pedogenesis together with plant-succession modifications under temperate-climate conditions. Brunic or luvic horizons are formed within the coversand deposits. Pseudogleyic conditions developed along the lithological discontinuities. Of note, sand-wedge casts (SWCs) occupy specific locations in the profiles that provide the vertical migration of water, base components and iron. Reducing conditions that occurred along the bottom of ice-wedge casts favour the formation of gleyic horizon. SWCs that have been ultimately modified into ice-wedge and acted as sand-wedge-affiliated geochemical corridors (SWGC) for shallow groundwater forming natural tile drains.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
We perform a growth accounting exercise using the whole neoclassical growth model for the u.s. economy during 1954–2017. Our growth accounting exercise reveals that the u.s. extraordinary economic ...growth in the 1960s has been mainly driven by the increase of the labor efficiency, whereas the growth slowdowns in the 1970s and the first decade of 21st century were mainly driven by the decline in the capital efficiency. However, the reduction of the distortions on the labor supply driven the subsequent recoveries in the 1980s and after the Great Recession.
•Factor efficiency drove the U.S. evolution of productivity and factor shares.•Economic growth in the Long Boom was driven by the increase of labor efficiency.•Decline in capital efficiency drove the U.S. growth slowdowns.•Reduction of distortions in the labor supply drove the U.S. economic recoveries.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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