Advances in numerical weather prediction represent a quiet revolution because they have resulted from a steady accumulation of scientific knowledge and technological advances over many years that, ...with only a few exceptions, have not been associated with the aura of fundamental physics breakthroughs. Nonetheless, the impact of numerical weather prediction is among the greatest of any area of physical science. As a computational problem, global weather prediction is comparable to the simulation of the human brain and of the evolution of the early Universe, and it is performed every day at major operational centres across the world.
Can models that are based on deep learning and trained on atmospheric data compete with weather and climate models that are based on physical principles and the basic equations of motion? This ...question has been asked often recently due to the boom in deep-learning techniques. The question is valid given the huge amount of data that are available, the computational efficiency of deep-learning techniques and the limitations of today's weather and climate models in particular with respect to resolution and complexity.In this paper, the question will be discussed in the context of global weather forecasts. A toy model for global weather predictions will be presented and used to identify challenges and fundamental design choices for a forecast system based on neural networks.
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•Closed Hollow Cathode PVD was applied for deposition TiAlCrYSi coatings on TiAl.•The growth mechanism and phase transformations in the coating are characterized.•The TiAlCrYSi ...coating provides excellent oxidation resistance at 850 °C.•Microstructural proof is provided for the Cr effect on the formation of α-Al2O3.•The segregation of yttrium to the grain boundaries of α-Al2O3 is evidenced.
The paper presents the application of Closed Hollow Cathode Physical Vapor Deposition (CHC-PVD) method for the depostion of Ti-Al-Cr-Y-Si coatings on γ-TiAl 48-2-2 alloy for high temperature oxidation protection. The study concerned the analysis of the coating’s growth mechanism, initial microstructure as well as phase transformations investigations using high resolution Scanning Transmission Electron Microscopy (STEM) and high temperature X-ray diffraction (HT-XRD). The coated alloy was subjected to high temperature oxidation test at 850 °C where a fivefold lower mass gain compared to bare 48-2-2 alloy was observed. Detailed microstructural investigations allowed to characterize the thermally grown oxide scale, which was found to be composed of nanometric layers of titania, equiaxed (Al,Cr)2O3 and columnar alumina. These investigations provided microstructural evidence for the Cr effect on the formation of Al2O3, which was postulated previously. Yttrium was found to segregate to the grain boundaries of alumina oxide scale during high temperature oxidation, indicating the occurence of the reactive element effect.
A stochastic energy aware routing framework is proposed for electric vehicles with the goal of enhancing the sustainability of future electrified transportation systems. A stochastic decision making ...framework is introduced to handle the random effects of environmental factors on transportation energy cost. The problem of optimal routing is formulated as a stochastic programming problem and risk control of the overall energy is applied to find the minimum energy route. The original discrete optimization problem is tackled using convex relaxation and transformation. The optimal path is constructed using a highly efficient primal-dual interior point algorithm for the relaxed problem with a subsequent reconstruction of the solution for the original discrete problem. Two electric drive limitations, i.e., battery capacity and drive line efficiency, are made an integral part of the decision making framework in order to obtain realistic results by incorporating actual vehicle data. Detailed simulations demonstrate the utility of the introduced approach and its superiority to existing, traditional routing engines.
A Leica RTC360 laser scanner was investigated using a linear horizontal comparator system with four targets of different reflectance. Several thousand panorama scans were conducted along the 30 m ...long comparator, basically in 40 mm steps. For a selected target, more detailed investigations were carried out with a 2 mm step width for a 2 m wide section. The absolute offset between the scanner and the relative interferometer measurements was determined with a calibrated total station. The investigations revealed several systematic effects like an offset in the distance measurement of about 1.3 mm. Furthermore, sections with stochastic behavior as well as sections with pseudo-cyclic parts were observed, depending on the reflectance of the target. The deterministic sections showed curved and striped patterns with some discontinuities of about 2 mm at 20 m, resulting in a saw-tooth like pattern along the distances. Within all the experiments, the distance deviations were below the manufacturer specifications of the 3D point accuracy. However, it was demonstrated that the distance measurements had clear systematic components. In using these new findings, the specification of the measurement “noise” in the data sheet has to be seen as critical.
•IMERG early and final are comprehensively evaluated across Mainland China.•All evaluated products perform better in humid areas than in arid areas.•Hydrological simulations are carried out over 300 ...catchments across Mainland China.•IMERG early provides comparable performance.•IMERG performs better than TRMM 3B42 as hydrological model forcing.
Accurate precipitation estimates are essential for reliable hydrological simulations of fluxes and states. Satellite precipitation products have been widely used for hydrological applications, especially for ungauged regions. The Global Precipitation Measurement (GPM) product is starting to provide a new generation of precipitation estimates. This work first evaluates several GPM Integrated Multi-satellite Retrievals (IMERG) against gauge-based precipitation over Mainland China for a two-year period (2016–2017), and then explores the feasibility of using GPM to force a lumped hydrological model over 300 catchments of varying size and climate.
The analysis indicates that IMERG Final run estimates (gauge-adjusted) agree well with gauge-based precipitation at daily scale, while IMERG Early run estimates (near-real time without gauge adjustments) are consistently lower than the rain gauge records. Nevertheless, both Final run and Early run estimates are slightly better than TRMM 3B42 estimates in terms of rainfall detection skill. Moreover, all three products show better skill over humid regions than over high elevation zones.
When used as hydrological model forcing, IMERG Final and Early estimates provide comparable performances to gauge-based precipitation. However, TRMM 3B42 performs relatively poor in terms of hydrological simulation. Moreover, models generally perform better in humid than in arid areas for all three products. The evaluation sheds light on how IMERG-driven hydrological predictions perform in different regions across China. The findings also indicate the potential of IMERG Early run for flood forecasting and Final run for climatological/hydrological modeling in ungauged or poorly gauged basins.
This paper introduces an adaptive multiresolution framework for electric vehicle (EV) energy consumption estimation with real-time capability. Three key parameters, namely powertrain efficiency, wind ...speed, and rolling resistance, are adaptively estimated using a two-step nonlinear iterative algorithm. Based on this algorithm, a multichannel framework for high-resolution powertrain efficiency estimation is introduced. Employing the "connected vehicles" concept, more reliable trip level energy estimates are achieved by sharing sensed environmental information. In addition, state-of-charge aware energy cost prediction methods of different accuracy and complexity are introduced to combat range anxiety and reduce computational complexity during times of high energy reserves. A variety of detailed simulations illustrate the introduced concept and its benefits for future EV systems.
Observation errors in all‐sky data assimilation Geer, Alan J.; Bauer, Peter
Quarterly journal of the Royal Meteorological Society,
October 2011 Part B, Letnik:
137, Številka:
661
Journal Article
The paper deals with high temperature oxidation behavior of EB-PVD TBCs on a 48–2–2 TiAl alloy with a TiAlCrYSi bond coating. The samples were subjected to the cyclic oxidation test at 900 °C in ...1-hour cycles up to 1000 cycles. Special focus was paid to STEM investigations of the interfacial phenomena occurring in the TBCs. The pre-oxidation treatment resulted in formation of a thermally grown oxide with outer Cr-rich γ-Al2O3 as well as nanometric TiO2, Y2O3 and Y3Al5O12 and inner α-Al2O3 that grew during the oxidation test at 900 °C. Yttrium segregation to α-Al2O3 grain boundaries was evidenced using STEM.
•Initial TGO consists of Cr-rich ɣ-Al2O3 with nanometric TiO2, Y3Al5O12 and Y2O3.•Internal zone of the TGO contains Cr-free α-Al2O3 at the scale/metal interface.•7YSZ top coating remains adherent up to 1000 1-hour cycles at 900 °C.•TiAlCrYSi bond coating provides 0.42 mg/cm2 of mass gain during 1000 cycles at 900 °C.•Yttrium segregation found at α-Al2O3 grain boundaries after the cyclic oxidation test.
Expansion of CAG trinucleotide repeat within the coding region of several genes results in the production of proteins with expanded polyglutamine (PolyQ) stretch. The expression of these pathogenic ...proteins leads to PolyQ diseases, such as Huntington's disease or several types of spinocerebellar ataxias. This family of neurodegenerative disorders is characterized by constant progression of the symptoms and molecularly, by the accumulation of mutant proteins inside neurons causing their dysfunction and eventually death. So far, no effective therapy actually preventing the physical and/or mental decline has been developed. Experimental therapeutic strategies either target the levels or processing of mutant proteins in an attempt to prevent cellular deterioration, or they are aimed at the downstream pathologic effects to reverse or ameliorate the caused damages. Certain pathomechanistic aspects of PolyQ disorders are discussed here. Relevance of disease models and recent knowledge of therapeutic possibilities is reviewed and updated.
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