Inhomogeneity in the Network Order of Device Quality a-Si:H

1993 ◽  
Vol 297 ◽  
Author(s):  
G. Morell ◽  
R.S. Katiyar ◽  
S.Z. Weisz ◽  
M. Gomez ◽  
I. Balberg
Keyword(s):  
Free Surface ◽  
Dihedral Angle ◽  
Hydrogen Concentration ◽  
Angle Distribution ◽  
Length Scales ◽  
Bond Stretching ◽  
Degree Of Order

In this paper we show that the degree of order of the Si network in a-Si:H is increasing with two length scales from the surface into the bulk. The major manifestation of the disorder is the variation in the Si-Si bond-stretching rather than the variation in the width of the dihedral angle distribution. The results are interpreted in terms of the decrease of the hydrogen concentration from the free surface into the bulk.

Sequence Specific Dihedral Angle Distribution: Application in Protein Structure Prediction and Evaluation

1970 ◽  
Vol 19 (2) ◽  
pp. 217-226
Author(s):  
S. M. Minhaz Ud-Dean ◽  
Mahdi Muhammad Moosa
Keyword(s):  
Protein Structure ◽  
Dihedral Angle ◽  
Protein Structure Prediction ◽  
Structure Prediction ◽  
Protein Structures ◽  
Angle Distribution ◽  
Ramachandran Plot ◽  
Specific Data ◽  
Specific Distribution ◽  
Structure Evaluation

Protein structure prediction and evaluation is one of the major fields of computational biology. Estimation of dihedral angle can provide information about the acceptability of both theoretically predicted and experimentally determined structures. Here we report on the sequence specific dihedral angle distribution of high resolution protein structures available in PDB and have developed Sasichandran, a tool for sequence specific dihedral angle prediction and structure evaluation. This tool will allow evaluation of a protein structure in pdb format from the sequence specific distribution of Ramachandran angles. Additionally, it will allow retrieval of the most probable Ramachandran angles for a given sequence along with the sequence specific data. Key words: Torsion angle, φ-ψ distribution, sequence specific ramachandran plot, Ramasekharan, protein structure appraisal D.O.I. 10.3329/ptcb.v19i2.5439 Plant Tissue Cult. & Biotech. 19(2): 217-226, 2009 (December)

Characteristics of Swirl Angle in Pump Intake Flow Near the Minimum Inlet Submergence

2019 ◽  
Author(s):  
Tajul Ariffin Norizan ◽  
Zambri Harun ◽  
Wan Hanna Melini Wan Mohtar ◽  
Shahrir Abdullah
Keyword(s):  
Free Surface ◽  
Swirling Flow ◽  
Pump Efficiency ◽  
Angle Distribution ◽  
Pump Impeller ◽  
Load Imbalance ◽  
Swirl Angle ◽  
Free Surface Vortex ◽  
Pump Inlet ◽  
Intake Flow

Abstract Swirling flow in pump sump intake has been the subject of discussion for the past decades due to the detrimental effects brought about by its existence. Among the effects of swirling flow are reduced pump efficiency, cavitation, excessive vibration and load imbalance at the pump impeller which are caused by hydraulic problems associated to swirling flow such as swirls and vortices. One of the remedial measures for preventing such occasion is by keeping the pump inlet submerged above a defined value known as the minimum inlet submergence. It is the minimum submergence required to reduce the probability of the occurrence of free surface vortices. However, this requirement may not be fulfilled in some situations due to on site conditions or operational restrictions. In this paper, an experimental study was conducted to investigate the characteristics of swirl angle in the pump intake flow when the pump inlet is submerged near the value of minimum inlet submergence. The ratio of pump submergence to the minimum submergence was varied between 0.8 to 1.2 with constant inlet Froude Number which referred to as submergence ratio. The strength of the swirl in the intake flow was determined by measuring the swirl angle which was accomplished using a swirl meter attached in the suction pipe. Measurements using Acoustic Doppler Velocimeter (ADV) was performed to capture the velocity profile in the intake sump. The swirl angle distribution across the range of submergence ratios was dominated by a subsurface vortex formed at the sump floor. As soon as the submergence was reduced below the minimum submergence, a free surface vortex emerged near the pump inlet and brought a swirl retardation effect to the swirl meter rotation resulting in a bigger fluctuation of the swirl meter reading. An anti vortex device (AVD) called the floor splitter commonly used to reduce vorticity at pump inlet was installed and its effect on the reduction of swirls and vortices was evaluated.

scholarly journals Turbulence at Free Surface in Hydraulic Jumps

Volume 1 ◽  
2004 ◽  
Author(s):  
D. Mouaze ◽  
F. Murzyn ◽  
J. R. Chaplin
Keyword(s):  
Free Surface ◽  
Mixing Layer ◽  
Hydraulic Jumps ◽  
Similar Data ◽  
Two Phase ◽  
Length Scales ◽  
Phase Measurements ◽  
Void Fractions ◽  
Cross Correlation Analysis ◽  
Turbulence Length

In the context of recent work by Brocchini & Peregrine [1,2], this paper aims to document free surface profiles, and turbulence length scales in hydraulic jumps with Froude numbers between 1.98 and 4.82. Although information on bubble size, frequency and velocities in hydraulic jumps is available in the literature, there is not much data on the features of the free surface, or on mixing layer thickness. In the present case, measurements at the free surface have been realized with two miniature resistive wire gauges each comprising two parallel 50 micron diameter wires with a separation of 1mm. These instruments were calibrated dynamically over a range of frequencies up to 20 Hz. Furthermore optical probes were used to measure properties of the air phase within the jump, including void fractions (up to 98%). The present results extend the range of Froude numbers for which two-phase measurements in hydraulic jumps are available, and, in most respects, confirm earlier results obtained with different experimental techniques. Length scales at the free surface are deduced from cross-correlation analysis of wire gauge measurements, and are compared with similar data obtained from images of the surface.

Length scales and the energy balance for turbulence near a free surface

AIAA Journal ◽  
1993 ◽  
Vol 31 (11) ◽  
pp. 1998-2007 ◽  
Author(s):  
R. A. Handler ◽  
T. F. Swean ◽  
R. I. Leighton ◽  
J. D. Swearingen
Keyword(s):  
Free Surface ◽  
Energy Balance ◽  
Length Scales

INFLUENCE OF THE COLLISION ENERGY ON STEREODYNAMICS OF THE F + LiH (v = 0, j = 0) → LiF + H REACTION

2011 ◽  
Vol 10 (04) ◽  
pp. 401-410
Author(s):  
TAO WANG ◽  
XIANGYANG MIAO
Keyword(s):  
Angular Momentum ◽  
Angular Distribution ◽  
Potential Energy ◽  
Potential Energy Surface ◽  
Dihedral Angle ◽  
Collision Energy ◽  
Energy Surface ◽  
Classical Trajectory ◽  
Angle Distribution ◽  
Title Reaction

The stereodynamics of the title reaction based on the ground 2A′ potential energy surface (PES) has been investigated using the method of the quasi-classical trajectory (QCT) at different collision energies (23 kcal/mol, 35 kcal/mol and 46 kcal/mol). The vector properties of the angular momentum (described by the distribution of K - J′P(θr), the dihedral angle distribution of K - K′ - J′P(φr) and the angular distribution P(θr, ϕr)) and the four PDDCSs [(2π/σ)(dσ00/dωt), (2π/σ)(dσ20/dωt), (2π/σ)(dσ22+/dωt), (2π/σ)(dσ21-/dωt)] of the product LiF at each collision energy have been presented, respectively. Further, the collision energy effects on the behavior of the product LiF have been discussed and studied.

scholarly journals Free Surface Length Scale Estimation in Hydraulic Jumps

2005 ◽  
Vol 127 (6) ◽  
pp. 1191-1193 ◽  
Author(s):  
D. Mouaze ◽  
F. Murzyn ◽  
J. R. Chaplin
Keyword(s):  
Free Surface ◽  
Cross Correlation ◽  
Mixing Layer ◽  
Hydraulic Jumps ◽  
Similar Data ◽  
Two Phase ◽  
Length Scales ◽  
Phase Measurements ◽  
Cross Correlation Analysis ◽  
Surface Length

In the context of recent work by Brocchini and Peregrine [J. Fluid Mech., 449, pp. 225–254 (2001a); 449, pp. 255–290 (2001b)] in this paper we aim to document free surface elevations and free surface length scales in hydraulic jumps with Froude numbers between 1.98 and 4.82. Although information on bubble size, frequency, and velocities in hydraulic jumps is available in the literature, there is not much data on the features of the free surface, or on mixing layer thickness. In the present case, measurements at the free surface have been realized with two “homemade” miniature resistive wire gauges made of two parallel 50μm diameter wires 1mm apart. These instruments were calibrated dynamically over a range of frequencies up to 20Hz. The present results extend the range of Froude numbers for which two-phase measurements in hydraulic jumps are available. In most respects, it confirms earlier results obtained with different experimental techniques. Length scales at the free surface are deduced from a cross-correlation analysis of wire gauge measurements, and are compared with similar data obtained from images of the surface.

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