scholarly journals Observations of the Small-Scale Variability of Precipitation Using an Imaging Radar

2005 ◽  
Vol 22 (8) ◽  
pp. 1122-1137 ◽  
Author(s):  
Robert D. Palmer ◽  
Boon Leng Cheong ◽  
Michael W. Hoffman ◽  
Stephen J. Frasier ◽  
F. J. López-Dekker
Keyword(s):  
Three Dimensional ◽  
Time History ◽  
Field Of View ◽  
Dimensional Structure ◽  
Small Scale ◽  
Destructive Effect ◽  
Advantages And Disadvantages ◽  
Imaging Radar ◽  
Boundary Layer Turbulence ◽  
Turbulent Eddy Profiler

Abstract For many years, spatial and temporal inhomogeneities in precipitation fields have been studied using scanning radars, cloud radars, and disdrometers, for example. Each measurement technique has its own advantages and disadvantages. Conventional profiling radars point vertically and collect data while the atmosphere advects across the field of view. Invoking Taylor’s frozen turbulence hypothesis, it is possible to construct time-history data, which are used to study the structure and dynamics of the atmosphere. In the present work, coherent radar imaging is used to estimate the true three-dimensional structure of the atmosphere within the field of view of the radar. The 915-MHz turbulent eddy profiler radar is well suited for imaging studies and was used in June 2003 to investigate the effects of turbulence on the formation of rain. The Capon adaptive algorithm was implemented for imaging and clutter rejection purposes. In the past several years, work by the authors and others has proven the Capon method to be effective in this regard and to possess minimal computational burden. A simple but robust filtering procedure is presented whereby echoes from precipitation and clear-air turbulence can be separated, facilitating the study of their interaction. By exploiting the three-dimensional views provided by this imaging radar, it is shown that boundary layer turbulence can have either a constructive or destructive effect on the formation of precipitation. Evidence is also provided that shows that this effect can be enhanced by updrafts in the wind field.

Atmospheric Factors Governing Banded Orographic Convection

2005 ◽  
Vol 62 (10) ◽  
pp. 3758-3774 ◽  
Author(s):  
Daniel J. Kirshbaum ◽  
Dale R. Durran
Keyword(s):  
Three Dimensional ◽  
Heavy Precipitation ◽  
Thermal Fluctuations ◽  
Dominant Mode ◽  
Vertical Shear ◽  
Dimensional Structure ◽  
Small Scale ◽  
Atmospheric Structure ◽  
Orographic Convection ◽  
Orographic Cloud

Abstract The three-dimensional structure of shallow orographic convection is investigated through simulations performed with a cloud-resolving numerical model. In moist flows that overcome a given topographic barrier to form statically unstable cap clouds, the organization of the convection depends on both the atmospheric structure and the mechanism by which the convection is initiated. Convection initiated by background thermal fluctuations embedded in the flow over a smooth mountain (without any small-scale topographic features) tends to be cellular and disorganized except that shear-parallel bands may form in flows with strong unidirectional vertical shear. The development of well-organized bands is favored when there is weak static instability inside the cloud and when the dry air surrounding the cloud is strongly stable. These bands move with the flow and distribute their cumulative precipitation evenly over the mountain upslope. Similar shear-parallel bands also develop in flows where convection is initiated by small-scale topographic noise superimposed onto the main mountain profile, but in this case stronger circulations are also triggered that create stationary rainbands parallel to the low-level flow. This second dominant mode, which is less sensitive to the atmospheric structure and the strength of forcing, is triggered by lee waves that form over small-scale topographic bumps near the upstream edge of the main orographic cloud. Due to their stationarity, these flow-parallel bands can produce locally heavy precipitation amounts.

scholarly journals The methods used for the diagnosis and evaluation of scoliosis

2016 ◽  
Vol 9 (17) ◽  
pp. 36-41 ◽  
Author(s):  
Ana-Maria Vutan ◽  
Erwin-Christian Lovasz ◽  
Mihaela Amarandei ◽  
Valentin Ciupe
Keyword(s):  
Three Dimensional ◽  
Growth Period ◽  
Small Scale ◽  
X Rays ◽  
Hematopoietic Tissue ◽  
X Ray ◽  
Advantages And Disadvantages ◽  
Non Invasive ◽  
Three Dimensional Mapping ◽  
Clinical Control

Abstract In recent years there multiple studies have been carried out on early diagnosis of scoliosis on school and preschool children. The diagnosis and evaluation of scoliosis is done by carrying out X-rays. A protocol is implemented for tracking the evolution of a scoliosis which involves both clinical control and imaging (X-ray) every 6 months, until the end of the growth period of the child. Because investigations such as X-ray and CT, can have harmful effects on the child's growing body (recent studies have shown that X-ray affects the skin, eyes, hematopoietic tissue, gonads and may cause cancer), new methods for diagnosing and tracking the evolution in time were researched. The present paper tries to present the current methods used in the diagnosis and assessment of scoliosis evolution in time, pointing out the main advantages and disadvantages of each method. There are a few methods developed in recent years in Germany by Zebris Medical Gmbh (using mapping with ultrasonic digital equipment), in Canada by InSpeck (using three-dimensional mapping through digital image acquisition) but used on a small scale. The newly developed methods have the advantage of being non-invasive, painless, non-irradiating and they can be used regardless of health status or gender. Although medical technology has developed very rapidly in recent years, radiology remains the most common method of investigation used for scoliosis. Certainly, in the near future the methods presented in this paper could be used more widely, for the benefits arising from their use.

Crystallization

2015 ◽  
Author(s):  
Roger G. Harrison ◽  
Paul W. Todd ◽  
Scott R. Rudge ◽  
Demetri P. Petrides
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Crystal Form ◽  
Solid Particles ◽  
Dimensional Structure ◽  
Internal Quality ◽  
Small Scale ◽  
X Ray Diffraction ◽  
Production Scale ◽  
Homogeneous Phase

Crystallization is the process of producing crystals from a homogeneous phase. For biochemicals, the homogeneous phase from which crystals are obtained is always a solution. Crystallization is similar to precipitation in that solid particles are obtained from a solution. However, precipitates have poorly defined morphology, while in crystals the constituent molecules are arranged in three-dimensional arrays called space lattices. In comparison to crystallization, precipitation occurs at much higher levels of supersaturation and rates of nucleation but lower solubilities. These and other differences between crystallization and precipitation are highlighted in Table 9.1. Because of these differences and because the theory of crystallization that has been developed is different from that for precipitation, crystallization is considered separately from precipitation. Crystallization is capable of producing bioproducts at very high purity (say, 99.9%) and is considered to be both a polishing step and a purification step. Polishing refers to a process needed to put the bioproduct in its final form for use. For some bioproducts, such as antibiotics, this final form must be crystalline, and sometimes it is even necessary that a specific crystal form be obtained. In some instances, the purification that can be achieved by crystallization is so significant that other more expensive purification steps such as chromatography can be avoided. There are actually two very different applications of crystallization in biotechnology and bioproduct engineering: crystallization for polishing and purification, and crystallization for crystallography. In the latter case, the goal is a small number of crystals with good size (0.2–0.9 mm) and internal quality. Although it has become common to crystallize proteins for characterization of their three-dimensional structure by x-ray diffraction, this is performed only at small scale in the laboratory, and the knowledge about how to crystallize proteins at large scale in a production process is less developed. However, many antibiotics and other small biomolecules are routinely crystallized in production scale processes. This chapter is oriented toward the use of crystallization in processes that can be scaled up.

Topology models of anion exchanger 1 that incorporate the anti-parallel V-shaped motifs found in the EM structureThis paper is one of a selection of papers published in a Special Issue entitled CSBMCB 53rd Annual Meeting — Membrane Proteins in Health and Disease, and has undergone the Journal’s usual peer review process.

2011 ◽  
Vol 89 (2) ◽  
pp. 148-156 ◽  
Author(s):  
Teruhisa Hirai ◽  
Naotaka Hamasaki ◽  
Tomohiro Yamaguchi ◽  
Yohei Ikeda
Keyword(s):  
Anion Exchanger ◽  
Peer Review Process ◽  
Three Dimensional ◽  
Structural Similarity ◽  
Dimensional Structure ◽  
Membrane Bilayer ◽  
Anion Exchanger 1 ◽  
Advantages And Disadvantages ◽  
Health And Disease ◽  
Selection Of

We recently published the three-dimensional structure of the membrane domain of human erythrocyte anion exchanger 1 (AE1) at 7.5 Å resolution, solved by electron crystallography. The structure exhibited distinctive anti-parallel V-shaped motifs, which protrude from the membrane bilayer on both sides. Similar motifs exist in the previously reported structure of a bacterial chloride channel (ClC)-type protein. Here, we propose two topology models of AE1 that reflect the anti-parallel V-shaped structural motifs. One is assumed to have structural similarity with the ClC protein and the other is only assumed to have internal repeats, as is often the case with transporters. Both models are consistent with most topological results reported thus far for AE1, each having advantages and disadvantages.

scholarly journals Generation of gravity waves from thermal tides in the Venus atmosphere

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Norihiko Sugimoto ◽  
Yukiko Fujisawa ◽  
Hiroki Kashimura ◽  
Katsuyuki Noguchi ◽  
Takeshi Kuroda ◽  
...  
Keyword(s):  
Gravity Waves ◽  
General Circulation ◽  
Three Dimensional ◽  
Circulation Model ◽  
Cloud Layer ◽  
Dimensional Structure ◽  
Wave Radiation ◽  
Small Scale ◽  
Thermal Tides ◽  
Venus Atmosphere

AbstractGravity waves play essential roles in the terrestrial atmosphere because they propagate far from source regions and transport momentum and energy globally. Gravity waves are also observed in the Venus atmosphere, but their characteristics have been poorly understood. Here we demonstrate activities of small-scale gravity waves using a high-resolution Venus general circulation model with less than 20 and 0.25 km in the horizontal and vertical grid intervals, respectively. We find spontaneous gravity wave radiation from nearly balanced flows. In the upper cloud layer (~70 km), the thermal tides in the super-rotation are primary sources of small-scale gravity waves in the low-latitudes. Baroclinic/barotropic waves are also essential sources in the mid- and high-latitudes. The small-scale gravity waves affect the three-dimensional structure of the super-rotation and contribute to material mixing through their breaking processes. They propagate vertically and transport momentum globally, which decelerates the super-rotation in the upper cloud layer (~70 km) and accelerates it above ~80 km.

scholarly journals Horizontal Vortex Tubes near a Simulated Tornado: Three-Dimensional Structure and Kinematics

Atmosphere ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 716 ◽  
Author(s):  
Oliveira ◽  
Xue ◽  
Roberts ◽  
Wicker ◽  
Yussouf
Keyword(s):  
Wide Spectrum ◽  
Surface Wind ◽  
3D Structure ◽  
Three Dimensional ◽  
Surface Friction ◽  
Radar Data ◽  
Dimensional Structure ◽  
Small Scale ◽  
Near Surface ◽  
Vortex Tubes

Supercell thunderstorms can produce a wide spectrum of vortical structures, ranging from midlevel mesocyclones to small-scale suction vortices within tornadoes. A less documented class of vortices are horizontally-oriented vortex tubes near and/or wrapping about tornadoes, that are observed either visually or in high-resolution Doppler radar data. In this study, an idealized numerical simulation of a tornadic supercell at 100 m grid spacing is used to analyze the three-dimensional (3D) structure and kinematics of horizontal vortices (HVs) that interact with a simulated tornado. Visualizations based on direct volume rendering aided by visual observations of HVs in a real tornado reveal the existence of a complex distribution of 3D vortex tubes surrounding the tornadic flow throughout the simulation. A distinct class of HVs originates in two key regions at the surface: around the base of the tornado and in the rear-flank downdraft (RFD) outflow and are believed to have been generated via surface friction in regions of strong horizontal near-surface wind. HVs around the tornado are produced in the tornado outer circulation and rise abruptly in its periphery, assuming a variety of complex shapes, while HVs to the south-southeast of the tornado, within the RFD outflow, ascend gradually in the updraft.

OSIRIS observations of a tongue of NOx in the lower stratosphere at the Antarctic vortex edge: comparison with a high-resolution simulation from the Global Environmental Multiscale (GEM) model

2007 ◽  
Vol 85 (11) ◽  
pp. 1195-1207 ◽  
Author(s):  
C E Sioris ◽  
S Chabrillat ◽  
C A McLinden ◽  
C S Haley ◽  
Y J Rochon ◽  
...  
Keyword(s):  
Lower Stratosphere ◽  
Three Dimensional ◽  
Multiscale Model ◽  
Dimensional Structure ◽  
Small Scale ◽  
Breaking Wave ◽  
Austral Spring ◽  
Global Environmental ◽  
The Antarctic ◽  
Global Environmental Multiscale

Selected NOx profiles of the Antarctic lower stratosphere inferred from OSIRIS NO2 observations are presented from the austral spring of 2003. These observations show a tongue of NOx at 100 hPa, with a concentration typical of the middle stratosphere. Simulations with the Global Environmental Multiscale model show that this small-scale tongue of NOx-rich air descended into the lower stratosphere. The tongue was formed as a result of a Rossby wave breaking days earlier, transporting NOx from the pole, where larger concentrations had recently appeared, to the edge of the vortex. The three-dimensional structure of the breaking wave is illustrated in detail. PACS Nos.: 92.60.hf, 92.60.Xg, 93.30.Ca

scholarly journals The role of lignin in wood working processes using elevated temperatures: an abbreviated literature survey

2020 ◽  
Author(s):  
Zoltán Börcsök ◽  
Zoltán Pásztory
Keyword(s):  
Cell Walls ◽  
Elevated Temperatures ◽  
Three Dimensional ◽  
Solid Wood ◽  
Literature Survey ◽  
Industrial Processes ◽  
Dimensional Structure ◽  
Advantages And Disadvantages ◽  
Surface Densification

AbstractThe lignin, cellulose and hemicelluloses in wood are polymers that behave similarly to the artificial polymers and are bonded together in wood. Lignin differs from the other two substances by its highly branched, amorphous, three-dimensional structure. Under appropriate conditions, the moist lignin incorporated in the wood softens at about 100 °C and allows the molecules of it to deform in the cell walls. There are many advantages and disadvantages to this phenomenon. If we know this process accurately and the industrial areas where it matters, we may be able to improve these industrial processes. This article provides a brief theoretical summary of lignin softening and the woodworking processes where it plays a role: wood welding, pellet manufacturing, manufacturing binderless boards, solid wood bending, veneer manufacturing, and solid wood surface densification.

scholarly journals Recent progress in astrophysical plasma turbulence from solar wind observations

2016 ◽  
Vol 82 (6) ◽  
Author(s):  
C. H. K. Chen
Keyword(s):  
Solar Wind ◽  
Recent Progress ◽  
Three Dimensional ◽  
Turbulent Energy ◽  
Plasma Turbulence ◽  
Residual Energy ◽  
Dimensional Structure ◽  
Small Scale ◽  
Astrophysical Plasma ◽  
Cascade Models

This paper summarises some of the recent progress that has been made in understanding astrophysical plasma turbulence in the solar wind, fromin situspacecraft observations. At large scales, where the turbulence is predominantly Alfvénic, measurements of critical balance, residual energy and three-dimensional structure are discussed, along with comparison to recent models of strong Alfvénic turbulence. At these scales, a few per cent of the energy is also in compressive fluctuations, and their nature, anisotropy and relation to the Alfvénic component is described. In the small-scale kinetic range, below the ion gyroscale, the turbulence becomes predominantly kinetic Alfvén in nature, and measurements of the spectra, anisotropy and intermittency of this turbulence are discussed with respect to recent cascade models. One of the major remaining questions is how the turbulent energy is dissipated, and some recent work on this question, in addition to future space missions which will help to answer it, are briefly discussed.

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