scholarly journals Optimal Growth in Inertia–Gravity Wave Packets: Energetics, Long-Term Development, and Three-Dimensional Structure

2006 ◽  
Vol 63 (2) ◽  
pp. 414-434 ◽  
Author(s):  
Ulrich Achatz ◽  
Gerhard Schmitz
Keyword(s):  
Gravity Wave ◽  
Normal Mode Analysis ◽  
Three Dimensional ◽  
Optimal Growth ◽  
Static Stability ◽  
Mode Analysis ◽  
Dimensional Structure ◽  
Linear Wave ◽  
Invariant Structure ◽  
Three Dimensional Structure

Abstract Using a hierarchy of three models of increasing realism and complexity, and expanding on a previous study, optimal perturbations of inertia–gravity wave (IGW) packets are studied with respect to several aspects. It is shown that normal modes are comparatively less able to extract energy from the IGW over finite time due to their time-invariant structure, while singular vectors (SVs) can adjust their dynamical fields flexibly so as to optimize the statically enhanced roll and Orr mechanisms by which they grow. On longer time scales, where the time dependence of the IGW packet precludes a normal-mode analysis, optimal growth is found to further amplify suitable perturbations. The propagation characteristics of these exhibit critical layer interactions for horizontal propagation directions transverse with respect to the IGW, preventing significant vertical propagation, while parallel and obliquely propagating perturbations of sufficiently long horizontal scales are found to radiate gravity waves into altitudes not directly affected by the IGW. The SVs with shorter wavelengths, as found for short optimization times, stay confined via a linear wave duct near the altitude of least static stability where they are excited. At optimization times of the order of the IGW period the leading SVs, with an energy growth by about three orders of magnitude, propagate obliquely, possibly in correspondence to previous results by others from simulations of nonlinear IGW breakdown. The three-dimensional structure of SVs shows an amplitude modulation strictly confining the perturbations also to the horizontal location of least static stability, suggesting a picture of turbulence onset in IGW packets where local patches of growing perturbations initially dominate.

The Three-Dimensional Structure of Swirl-Stabilized Flames in a Lean Premixed Multinozzle Can Combustor

2015 ◽  
Vol 138 (3) ◽  
Author(s):  
Janith Samarasinghe ◽  
Stephen J. Peluso ◽  
Bryan D. Quay ◽  
Domenic A. Santavicca
Keyword(s):  
Gas Turbine ◽  
Tomographic Reconstruction ◽  
Flame Structure ◽  
Combustion Process ◽  
Three Dimensional ◽  
Static Stability ◽  
Dimensional Structure ◽  
Reconstruction Technique ◽  
Three Dimensional Structure ◽  
The Relationship

Flame structure can have a significant effect on a combustor's static stability (resistance to blowoff) and dynamic stability (combustion instability) and therefore is an important aspect of the combustion process that must be taken into account in the design of gas turbine combustors. While the relationship between flame structure and flame stability has been studied extensively in single-nozzle combustors, relatively few studies have been conducted in multinozzle combustor configurations typical of actual gas turbine combustion systems. In this paper, a chemiluminescence-based tomographic reconstruction technique is used to obtain three-dimensional images of the flame structure in a laboratory-scale five-nozzle can combustor. Analysis of the 3D images reveals features of the complex, three-dimensional structure of this multinozzle flame. Effects of interacting swirling flows, flame–flame interactions, and flame–wall interactions on the flame structure are also discussed.

The Three-dimensional structure of frozen-hydrated nudaurelia capensis β virus

1987 ◽  
Vol 45 ◽  
pp. 650-651
Author(s):  
N. H. Olson ◽  
T. S. Baker ◽  
Wu Bo Mu ◽  
J. E. Johnson ◽  
D. A. Hendry
Keyword(s):  
South African ◽  
Rna Virus ◽  
Carbon Film ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Electron Dose ◽  
Total Electron ◽  
Three Dimensional Structure ◽  
Negative Stain ◽  
Dimensional Reconstruction

Nudaurelia capensis β virus (NβV) is an RNA virus of the South African Pine Emperor moth, Nudaurelia cytherea capensis (Lepidoptera: Saturniidae). The NβV capsid is a T = 4 icosahedron that contains 60T = 240 subunits of the coat protein (Mr = 61,000). A three-dimensional reconstruction of the NβV capsid was previously computed from visions embedded in negative stain suspended over holes in a carbon film. We have re-examined the three-dimensional structure of NβV, using cryo-microscopy to examine the native, unstained structure of the virion and to provide a initial phasing model for high-resolution x-ray crystallographic studiesNβV was purified and prepared for cryo-microscopy as described. Micrographs were recorded ∼1 - 2 μm underfocus at a magnification of 49,000X with a total electron dose of about 1800 e-/nm2.

Three Dimensional structure and organization of diploid chromosomes by optical section microscopy

1987 ◽  
Vol 45 ◽  
pp. 633-635
Author(s):  
David A. Agard ◽  
Yasushi Hiraoka ◽  
John W. Sedat
Keyword(s):  
Dimensional Space ◽  
Three Dimensional ◽  
Developmental State ◽  
Mitotic Cell ◽  
Biological Properties ◽  
Dimensional Structure ◽  
Specific Gene ◽  
Three Dimensional Structure ◽  
Complementary Techniques ◽  
Dynamic Structures

In an effort to understand the complex relationship between structure and biological function within the nucleus, we have embarked on a program to examine the three-dimensional structure and organization of Drosophila melanogaster embryonic chromosomes. Our overall goal is to determine how DNA and proteins are organized into complex and highly dynamic structures (chromosomes) and how these chromosomes are arranged in three dimensional space within the cell nucleus. Futher, we hope to be able to correlate structual data with such fundamental biological properties as stage in the mitotic cell cycle, developmental state and transcription at specific gene loci.Towards this end, we have been developing methodologies for the three-dimensional analysis of non-crystalline biological specimens using optical and electron microscopy. We feel that the combination of these two complementary techniques allows an unprecedented look at the structural organization of cellular components ranging in size from 100A to 100 microns.

Three-Dimensional Structure of Cloned T3 Connector Protein at 1.6nm Resolution

1990 ◽  
Vol 48 (1) ◽  
pp. 282-283
Author(s):  
José L. Carrascosa ◽  
José M. Valpuesta ◽  
Hisao Fujisawa
Keyword(s):  
Dna Sequences ◽  
Expression Vector ◽  
Three Dimensional ◽  
Deae Cellulose ◽  
Dna Packaging ◽  
Dimensional Structure ◽  
Two Dimensional ◽  
Freezing And Thawing ◽  
Three Dimensional Structure ◽  
Dimensional Reconstruction

The head to tail connector of bacteriophages plays a fundamental role in the assembly of viral heads and DNA packaging. In spite of the absence of sequence homology, the structure of connectors from different viruses (T4, Ø29, T3, P22, etc) share common morphological features, that are most clearly revealed in their three-dimensional structure. We have studied the three-dimensional reconstruction of the connector protein from phage T3 (gp 8) from tilted view of two dimensional crystals obtained from this protein after cloning and purification.DNA sequences including gene 8 from phage T3 were cloned, into Bam Hl-Eco Rl sites down stream of lambda promotor PL, in the expression vector pNT45 under the control of cI857. E R204 (pNT89) cells were incubated at 42°C for 2h, harvested and resuspended in 20 mM Tris HC1 (pH 7.4), 7mM 2 mercaptoethanol, ImM EDTA. The cells were lysed by freezing and thawing in the presence of lysozyme (lmg/ml) and ligthly sonicated. The low speed supernatant was precipitated by ammonium sulfate (60% saturated) and dissolved in the original buffer to be subjected to gel nitration through Sepharose 6B, followed by phosphocellulose colum (Pll) and DEAE cellulose colum (DE52). Purified gp8 appeared at 0.3M NaCl and formed crystals when its concentration increased above 1.5 mg/ml.

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