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The Atmosphere over Mountainous Regions

Authors: --- --- --- --- et al.
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889450169 Year: Pages: 160 DOI: 10.3389/978-2-88945-016-9 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Geography
Added to DOAB on : 2018-02-27 16:16:44
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Abstract

Mountainous regions occupy a significant fraction of the Earth’s continents and are characterized by specific meteorological phenomena operating on a wide range of scales. Being a home to large human populations, the impact of mountains on weather and hydrology has significant practical consequences. Mountains modulate the climate and create micro-climates, induce different types of thermally and dynamically driven circulations, generate atmospheric waves of various scales (known as mountain waves), and affect the boundary layer characteristics and the dispersion of pollutants. At the local scale, strong downslope winds linked with mountain waves (such as the Foehn and Bora) can cause severe damage. Mountain wave breaking in the high atmosphere is a source of Clear Air Turbulence, and lee wave rotors are a major near-surface aviation hazard. Mountains also act to block strongly-stratified air layers, leading to the formation of valley cold-air pools (with implications for road safety, pollution, crop damage, etc.) and gap flows. Presently, neither the fine-scale structure of orographic precipitation nor the initiation of deep convection by mountainous terrain can be resolved adequately by regional-to global-scale models, requiring appropriate downscaling or parameterization. Additionally, the shortest mountain waves need to be parameterized in global weather and climate prediction models, because they exert a drag on the atmosphere. This drag not only decelerates the global atmospheric circulation, but also affects temperatures in the polar stratosphere, which control ozone depletion. It is likely that both mountain wave drag and orographic precipitation lead to non-trivial feedbacks in climate change scenarios. Measurement campaigns such as MAP, T-REX, Materhorn, COLPEX and i-Box provided a wealth of mountain meteorology field data, which is only starting to be explored. Recent advances in computing power allow numerical simulations of unprecedented resolution, e.g. LES modelling of rotors, mountain wave turbulence, and boundary layers in mountainous regions. This will lead to important advances in understanding these phenomena, as well as mixing and pollutant dispersion over complex terrain, or the onset and breakdown of cold-air pools. On the other hand, recent analyses of global circulation biases point towards missing drag, especially in the southern hemisphere, which may be due to processes currently neglected in parameterizations. A better understanding of flow over orography is also crucial for a better management of wind power and a more effective use of data assimilation over complex terrain. This Research Topic includes contributions that aim to shed light on a number of these issues, using theory, numerical modelling, field measurements, and laboratory experiments.

Processing-Structure-Property Relationships in Metals

Authors: ---
ISBN: 9783039217700 9783039217717 Year: Pages: 240 DOI: 10.3390/books978-3-03921-771-7 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Technology (General) --- General and Civil Engineering
Added to DOAB on : 2019-12-09 16:39:37
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In the industrial manufacturing of metals, the achievement of products featuring desired characteristics always requires the control of process parameters in order to obtain a suitable microstructure. The strict relationship among process parameters, microstructure, and mechanical properties is a matter of interest in different areas, such as foundry, plastic forming, sintering, welding, etc., and regards both well-established and innovative processes. Nowadays, circular economy and sustainable technological development are dominant paradigms and impose an optimized use of resources, a lower energetic impact of industrial processes and new tasks for materials and products. In this frame, this Special Issue covers a broad range of research works and contains research and review papers.

Keywords

titanium composites --- in situ secondary phases --- microstructure --- inductive hot pressing --- intermetallic --- bainite rail --- tempering --- retained austenite --- tensile property --- impact toughness --- cryorolling --- reduction --- ultrafine grain --- secondary recrystallization --- high strength --- microstructure inhomogeneity --- non-monotonic simple shear strains --- shear strain reversal --- severe plastic deformation --- texture inhomogeneity --- tensile properties --- Mg-10Y-6Gd-1.5Zn-0.5Zr --- ultra-fine grain --- aging treatment --- precipitation behavior --- mechanical property --- multimodal --- AZ91 alloy --- equal channel angular pressing --- aging --- high pressure die casting --- aluminum alloy --- prediction model --- process monitoring --- static mechanical behavior --- fracture surface --- microstructure. --- casting --- Al 6061 alloys --- shrinkage --- porosity --- steering knuckles --- Al alloys --- warm working --- mechanical properties --- dental materials --- metal posts --- computer-aided design (CAD) --- image analysis --- mechanical properties --- finite element analysis --- additive manufacturing --- Al alloys --- wear --- cavitation erosion --- SEM --- microstructure --- high speed steel --- nanostructured coatings --- thin films --- FEGSEM --- tribology --- Nb tube --- caliber-rolling --- grain boundaries --- texture --- electron backscatter diffraction --- damping --- aluminum film --- grain boundary --- anelasticity --- thin aluminum sheet --- alloys --- aeronautic applications --- mechanical properties --- corrosion resistance --- EBM --- SEBM --- macro-instrumented indentation test --- property-microstructure-process relationship --- mechanical properties --- indentation hardness --- indentation modulus --- tensile properties --- Ti-6Al-4V alloy --- ?-platelet thickness --- columnar microstructure --- n/a

Advances in Mechanical Problems of Functionally Graded Materials and Structures

Authors: --- --- ---
ISBN: 9783039216581 9783039216598 Year: Pages: 262 DOI: 10.3390/books978-3-03921-659-8 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Science (General) --- Mathematics
Added to DOAB on : 2019-12-09 11:49:16
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The book deals with novel aspects and perspectives in functionally graded materials (FGMs), which are advanced engineering materials designed for a specific performance or function with spatial gradation in structure and/or composition. The contributions mainly focus on numerical simulations of mechanical properties and the behavior of FGMs and FGM structures. Several advancements in numerical simulations that are particularly useful for investigations on FGMs have been proposed and demonstrated in this Special Issue. Such proposed approaches provide incisive methods to explore and predict the mechanical and structural characteristics of FGMs subjected to thermoelectromechanical loadings under various boundary and environmental conditions. The contributions have resulted in enhanced activity regarding the prediction of FGM properties and global structural responses, which are of great importance when considering the potential applications of FGM structures. Furthermore, the presented scientific scope is, in some way, an answer to the continuous demand for FGM structures, and opens new perspectives for their practical use.

Keywords

functionally graded beams --- different moduli in tension and compression --- bimodulus --- analytical solution --- neutral layer --- quadratic solid–shell elements --- finite elements --- functionally graded materials --- thin structures --- geometrically nonlinear analysis --- functionally graded piezoelectric materials --- circular plate --- combined mechanical loads --- electroelastic solution --- ANFIS --- fuzzy logic --- clustering --- neural networks --- robotics and contact wear --- evanescent wave --- polynomial approach --- functionally graded piezoelectric-piezomagnetic material --- dispersion --- attenuation --- functional graded saturated material --- inhomogeneity --- Love wave --- dispersion --- attenuation --- porous materials --- truncated conical sandwich shell --- metal foam core layer --- non-linear buckling analysis --- orthogonal stiffener --- elastic foundation --- functionally graded plate --- power-law distribution --- high order shear deformation theory --- elastic foundation --- stepped FG paraboloidal shell --- general edge conditions --- spring stiffness technique --- free vibration characteristics --- Lamb wave --- functionally graded viscoelastic material --- minimum module approximation method --- damping coefficient --- functionally graded materials --- finite element analysis --- graded finite elements --- functionally graded materials --- inhomogeneous composite materials --- material design --- stress concentration factor --- failure and damage --- elliptical hole --- finite element method --- hollow disc --- external pressure --- residual stress --- residual strain --- flow theory of plasticity --- functionally graded materials --- elastoplastic analysis --- pure bending --- residual stress --- large strain

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