The density dependence of the Hanle effect in the resonance line of atomic magnesium

1978 ◽  
Vol 56 (11) ◽  
pp. 1422-1425 ◽  
Author(s):  
F. M. Kelly ◽  
M. S. Mathur
Keyword(s):  
Density Dependence ◽  
Cross Section ◽  
Resonance Line ◽  
Neutral Atom ◽  
Ground Level ◽  
Hanle Effect ◽  
Wide Range

The Hanle width and hence the lifetime of the first excited 1P1 level of neutral magnesium have been measured over a wide range of densities. The natural lifetime of the 3s3p1P1 level is 2.00 ns. The depolarization cross section for collisions with the ground level neutral atom has been measured and [Formula: see text].

Hanle effect of the level of calcium and its density dependence

1982 ◽  
Vol 60 (9) ◽  
pp. 1237-1240 ◽  
Author(s):  
M. S. Mathur ◽  
F. M. Kelly
Keyword(s):  
Density Dependence ◽  
Cross Section ◽  
Ground Level ◽  
Neutral Atoms ◽  
Hanle Effect ◽  
Wide Range

The Hanle width and hence the lifetime of the [Formula: see text] level of neutral calcium has been measured over a wide range of densities. The natural lifetime of the [Formula: see text] level is 20.07 ns. The depolarization cross section for collision with the ground level neutral atoms has been measured and [Formula: see text].

The density dependence of the Hanle effect in the resonance line of atomic barium

1977 ◽  
Vol 55 (1) ◽  
pp. 83-91 ◽  
Author(s):  
F. M. Kelly ◽  
M. S. Mathur
Keyword(s):  
Cross Sections ◽  
Resonance Line ◽  
Excited Level ◽  
Ground Level ◽  
Multipole Moment ◽  
Low Density ◽  
Density Region ◽  
Hanle Effect ◽  
Wide Range ◽  
Theoretical Predictions

The change in the Hanle effect of the singlet resonance line of neutral barium has been studied over a wide range of density. The low density region has been used to confirm a lifetime of 8.37 ± 0.08 ns for the 6s6p1P1 level. We have determined the cross sections for the relaxation of the multipole moment of order 2 for collisions of the excited level with the ground level and with the metastable 6s5d1D2 level, and comparisons are made with the measured value of [Formula: see text] for the ground level with theoretical predictions.

Density dependence of the Hanle effect of the 4s4p1P1 level of neutral calcium

1980 ◽  
Vol 58 (7) ◽  
pp. 1004-1009 ◽  
Author(s):  
F. M. Kelly ◽  
M. S. Mathur
Keyword(s):  
Density Dependence ◽  
High Density ◽  
Low Density ◽  
Density Region ◽  
Hanle Effect ◽  
Wide Range ◽  
High Density Region

The Hanle effect in the 4s21S0–4s4p1P1 (4226.7 Å) transition in Ca I has been observed over a wide range of densities. The low density observations determine the lifetime of the 1P1 level to be 4.49 ns. Collision parameters are obtained from observations in the high density region.

Density dependence of the Hanle effect of the 3s4p1P10 level of neutral magnesium

1979 ◽  
Vol 57 (6) ◽  
pp. 838-840
Author(s):  
F. M. Kelly ◽  
M. S. Mathur
Keyword(s):  
Density Dependence ◽  
Excited Level ◽  
Lifetime Measurement ◽  
Oscillator Strengths ◽  
Low Density ◽  
Hanle Effect

The Hanle effect in the 3s2 1S0–3s4p1P1 (2026 Å) transition of Mg I has been studied over a range of densities. The low density observations lead to an accurate lifetime measurement of the 4p1P1 excited level. Related oscillator strengths are calculated.

MATHEMATICAL MODEL OF TWO-DIMENSIONAL LAYERED PRESSURE FLOW IN THE AUGER CHANNEL

2018 ◽  
Author(s):  
А.В. ГУКАСЯН ◽  
В.С. КОСАЧЕВ ◽  
Е.П. КОШЕВОЙ
Keyword(s):  
Mathematical Model ◽  
Analytical Solution ◽  
Cross Section ◽  
Dynamic Pressure ◽  
Two Dimensional ◽  
Flow Dynamic ◽  
Pressure Flow ◽  
Rectangular Channels ◽  
Wide Range ◽  
Pressure Characteristics

Получено аналитическое решение двумерного слоистого напорного течения в канале шнека, позволяющее моделировать расходно-напорные характеристики прямоугольных каналов шнековых прессов с учетом гидравлического сопротивления формующих устройств и рассчитывать расходно-напорные характеристики экструдеров в широком диапазоне геометрии витков как в поперечном сечении, так и по длине канала. Obtained the analytical solution of two-dimensional layered pressure flow in the screw channel, allow to simulate the flow-dynamic pressure characteristics of rectangular channels screw presses taking into account the hydraulic resistance of the forming device and calculate the mass flow-dynamic pressure characteristics of the extruders in a wide range of the geometry of the coils, as in its cross section and along the length of the channel.

Moderate Reynolds Number Mixing in a T-Channel

2010 ◽  
Author(s):  
Susan Thomas ◽  
Tim Ameel
Keyword(s):  
Reynolds Number ◽  
Cross Section ◽  
Rectangular Cross Section ◽  
Large Body ◽  
Experimental Studies ◽  
Numerical Work ◽  
Moderate Reynolds Number ◽  
Wide Range ◽  
Particle Imaging ◽  
Experimental Trials

An experimental investigation of water flow in a T-shaped channel with rectangular cross section (20 × 20 mm inlet ID and 20 × 40 mm outlet ID) has been conducted for a Reynolds number Re range of 56 to 422, based on inlet diameter. Dynamical conditions and the T-channel geometry of the current study are applicable to the microscale. This study supports a large body of numerical work, and resolution and the interrogation region are extended beyond previous experimental studies. Laser induced fluorescence (LIF) and particle imaging velocimetry (PIV) are used to characterize flow behaviors over the broad range of Re where realistic T-channels operate. Scalar structures previously unresolved in the literature are presented. Special attention is paid to the unsteady flow regimes that develop at moderate Re, which significantly impact mixing but are not yet well characterized or understood. An unsteady symmetric topology, which develops at higher Re and negatively impacts mixing, is presented, and mechanisms behind the wide range of mixing qualities predicted for this regime are explained. An optimal Re operating range is identified based on multiple experimental trials.

scholarly journals STABILITY OF AXIALLY LOADED TAPERED COLUMNS/CENTRIŠKAI GNIUŽDOMŲ TRAPECINIŲ KOLONŲ STABILUMAS

2000 ◽  
Vol 6 (3) ◽  
pp. 158-161 ◽  
Author(s):  
Vaidotas Špalas ◽  
Audronis Kazimieras Kvedaras
Keyword(s):  
Critical Load ◽  
Cross Section ◽  
Calculation Methods ◽  
Moments Of Inertia ◽  
Geometrical Characteristics ◽  
Wide Range ◽  
Axially Loaded ◽  
Tapered Columns ◽  
Loaded Column ◽  
Tapered Column

In this paper, theoretical analysis of tapered column's bearing capacity is presented. A slender axially loaded column loses stability, when it achieves critical load (1). Critical load for uniform column can be calculated using L. Euler's formula (3). But this formula is only for uniform members. When we have non-uniform member, column's moment of inertia about strong axis (Fig 3) chances according to law (4). A. N. Dinik [4] suggested a differential equation (6) for non-uniform axially loaded member. So the critical load of tapered column can be calculated as for uniform member with additional factor K using (7) formula. Factor Kdepends only on the moments of inertia ratio (5) of column ends. In this paper, critical load of tapered column was calculated using FE program COSMOS/M. A lot of simulation were carried out with a wide range of moments of inertia ratio. From these simulations factor K was calculated (Fig 4 and Table 1) for axially loaded pin-end column. By computer simulation it was determined that factor K for pin-end column can also be used for other types of column support. After determining critical load, column slenderness (10) can be calculated using column's smallest cross-section A 1. Tapered column must satisfy (12) condition. A couple of examples (Table 2) with various moments of inertia ratio was solved. Three calculation methods were used: the author's suggested (Fig 5 curve 1): using [1, 2] method as for uniform member with the smallest column's cross-section geometrical characteristics (Fig 5 curve 2); and using [1, 2] method as for uniform member with average column's cross-section geometrical characteristics (Fig 5 curve 3). From Fig 5 we see that calculation of tapered column using methods for uniform members with average cross-section geometrical characteristics is not safe.

scholarly journals Optimization of Geometrical Parameters of Hollow-core Slabs by Formwork-free Shaping for Construction in Seismic Areas

2020 ◽  
Vol 8 (6) ◽  
pp. 4973-4977
Keyword(s):  
Cross Section ◽  
High Strength ◽  
Geometrical Parameters ◽  
Hollow Core ◽  
Constructive Solution ◽  
Industrial Buildings ◽  
Operational Load ◽  
Wide Range ◽  
Hollow Core Slab ◽  
The Cross

The building norms and standards of Uzbekistan on the reinforced concrete structures do not regulate the design of hollow-core slabs of formwork-free shaping, reinforced with prestressed wire reinforcement. The manufacturing technology of such slabs allows creating a wide range of products that increase the possibility of their use in various structural systems in residential, civil and industrial buildings, but in non-seismic areas only. The aim of this work is to develop a constructive solution for the cross section of a prestressed hollow-core floor slab of bench formwork-free shaping, reinforced with high-strength wire reinforcement, in order to create a wide range of products intended for construction in seismic areas. To achieve the goal, the problem of determining the optimal combination of height and configuration parameters of the cross section of such a slab is solved, meeting the normalized operational requirements and limitations of earthquake-resistant building standards. The main variable parameters are the height and the void degree of the section, characterized by the size and shape of voids. In calculating the cross-section of a hollow-core slab when substantiating the theoretical basis for the calculation, the cross section is reduced to the equivalent I-section. As a result of research, a constructive solution was developed for the slab cross section of the maximum parameter values (the span, operational load) set by the customer. The parameters of the slab cross-section are: the height 190 mm, the hollowness 38%, the height of the upper thickened flange (compared with the height of the lower flange) of the given section is 0.27h, the height of the lower flange is 0.17h, the reduced (total) thickness of all ribs “b” is 0.32 of the width of the upper flange. The voids in the section along the height of the slab are arranged asymmetrically. A patent for a utility model has been received for the proposed constructive solution of the slab cross section.

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