Econometric Testing of the Displacement Effect: the Saudi Experience

Abstract Recent surveys of the literature on climate change and migration emphasize the important diversity of outcomes and approaches of the empirical studies. In this paper, we conduct a meta-analysis in order to investigate the role of the methodological choices of these empirical studies in finding some particular results concerning the role of climatic factors as drivers of human mobility. We code 51 papers representative of the literature in terms of methodological approaches. This results in the coding of more than 85 variables capturing the methodology of the main dimensions of the analysis at the regression level. These dimensions include authors' reputation, type of mobility, measures of mobility, type of data, context of the study, econometric methods, and last but not least measures of the climatic factors. We look at the influence of these characteristics on the probability of finding any effect of climate change, a displacement effect, an increase in immobility, and evidence in favor of a direct vs. an indirect effect. Our results highlight the role of some important methodological choices, such as the frequency of the data on mobility, the level of development, the measures of human mobility and of the climatic factors as well as the econometric methodology.

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Experimental Study on the Displacement Performance of Heat-Resistant Polymer

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.675-677.1495 ◽

2014 ◽

Vol 675-677 ◽

pp. 1495-1499 ◽

Cited By ~ 1

Author(s):

Tao Ping Chen ◽

Biao Qiu

Keyword(s):

Polymer Flooding ◽

Displacement Efficiency ◽

Oil Viscosity ◽

Permeability Ratio ◽

Ratio Increase ◽

Displacement Effect ◽

Oil Displacement ◽

Heat Resistant ◽

Homogeneous Core ◽

Oil Displacement Efficiency

The displacement performance of heat-resistant polymer is evaluated with the artificial cores and natural cores under 95°C. The best concentration of BH heat-resistant polymer is 1500 mg/L, and the best slug is 0.6 PV on the condition of the average permeability is 600×10-3μm2 of the homogeneous core and the oil viscosity is 2.3mPa • s. Under the best concentration and the PV size, BH heat-resistant polymer solution has better displacement effect for the artificial double core whose permeability ratio is less than 4. When permeability ratio exceed 4, the displacement affect no longer increase. When the mobility ratio increase from 0.05 to 0.2, for the artificial cores, the recovery of polymer flooding reduce by 3.17%, and for the natural cores, the recovery of polymer flooding reduce by 2.26%. The recovery of BH polymer that is aged for 90 days after vacuumed is 32.29%. Comparing with the fresh BH polymer, it is lower by 6.56%. That is to say that the aged BH polymer still has good oil displacement efficiency.

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The viscous secondary flow ahead of an infinite cylinder in a uniform parallel shear flow

Journal of Fluid Mechanics ◽

10.1017/s0022112060000098 ◽

1960 ◽

Vol 7 (1) ◽

pp. 145-155 ◽

Cited By ~ 5

Author(s):

Alar Toomre

Keyword(s):

Shear Flow ◽

Lateral Displacement ◽

Reynolds Numbers ◽

Infinite Cylinder ◽

List Type ◽

Displacement Effect ◽

Simple Method ◽

Viscous Shear ◽

Parallel Shear Flow ◽

Viscous Shear Flow

A simple method is presented in this paper for calculating the secondary velocities, andthe lateral displacement of total pressure surfaces (i.e. the ‘displacement effect’) in the plane of symmetry ahead of an infinitely long cylinder situated normal to a steady, incompressible, slightly viscous shear flow; the cylinder is also perpendicular to the vorticity, which is assumed uniform but small. The method is based on lateral gradients of pressure, these being calculated from the primary flow alone. Profiles of the secondary velocities are obtained at several Reynolds numbers ahead of two specific cylindrical shapes: a circular cylinder, and a flat plate normal to the flow. The displacement effect is derived and, rathe surprisingly, is found to be virtually independent of the Reynolds number.

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Abstract MP018: Moderate-to-Vigorous Physical Activity: Evidence for a Displacement Effect on Sedentary Behaviour

Circulation ◽

10.1161/circ.125.suppl_10.amp018 ◽

2012 ◽

Vol 125 (suppl_10) ◽

Author(s):

Katya M Herman ◽

Gilles Paradis ◽

Marie-Eve Mathieu ◽

Jennifer O'Loughlin ◽

Angelo Tremblay ◽

...

Keyword(s):

Physical Activity ◽

Sedentary Behaviour ◽

Video Game ◽

Parental Education ◽

Vigorous Physical Activity ◽

Sports Participation ◽

Tanner Stage ◽

Healthy Weight ◽

Obese Children ◽

Displacement Effect

Background: Sedentary behaviour has detrimental health consequences, distinct from those of physical inactivity. An individual can be both highly active and highly sedentary: While the displacement hypothesis proposes that time spent active displaces time that would otherwise be spent sedentary, the compensation hypothesis suggests that increased physical activity (PA) may be associated with increased sedentary behaviour (SED) in non-active time. Objectives: The aim was to assess whether higher levels of childhood participation in moderate to vigorous PA (MVPA) are associated with higher levels of SED, or whether time spent in SED is displaced by higher levels of MVPA. Methods: Participants were 290 boys and 245 girls aged 8–10 years in the QUebec Adipose and Lifestyle InvesTigation in Youth (QUALITY) study. PA and SED were assessed by accelerometer over a 1-week period (SED ≤ 100 cpm, MVPA ≥ 2296 cpm), and quantified as mean time spent per day. Total PA was the sum of light PA + MVPA. Self-reported data included sports participation (number of teams), television viewing and computer/video game use (hours/day). Spearman correlations and multiple linear regression (adjusting for age, sex, body mass index, Tanner stage, parental education, accelerometer wear-time) were used to assess associations between PA and SED variables. Results: Higher MVPA and VPA were negatively correlated with SED (r=−0.44 and −0.35; p<0.001), and positively correlated with total PA (r=0.58 and 0.45; p<0.001). SED was negatively correlated with TPA (r=−0.65, p<0.001). Only weak correlations were found between MVPA and sports participation, the latter not associated with SED. MVPA and VPA were not significantly correlated with TV, computer/video or total screen time; objectively measured SED was only weakly associated with specific sedentary behaviours. On average, for each additional 10 minutes of MVPA, children spent 14 minutes less in SED, or for each additional 5 minutes of VPA, 10 minutes less in SED. Associations were stronger in overweight/obese children compared to healthy weight children. Conclusions: Higher levels of MVPA in children displace SED, and are also associated with higher total PA over and above the additional amount of MVPA. The SED displacement benefits of higher MVPA may be greatest in overweight/obese children. Public health strategies should focus on both increasing PA and decreasing SED as essential targets to improve overall PA in children.

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The Displacement Effect of Public Pensions on the Accumulation of Financial Assets*

Fiscal Studies ◽

10.1111/j.1475-5890.2012.00154.x ◽

2012 ◽

Vol 33 (1) ◽

pp. 107-128 ◽

Cited By ~ 27

Author(s):

Michael Hurd ◽

Pierre-Carl Michaud ◽

Susann Rohwedder

Keyword(s):

Public Pensions ◽

Financial Assets ◽

Displacement Effect

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Modified Svensson’s Formula for More Accurate Burst Pressure Predictions of Thin Cylindrical Shells With Small Shell Length to Diameter Ratios

Volume 3: Design and Analysis ◽

10.1115/pvp2015-45316 ◽

2015 ◽

Author(s):

Sang-Guk Kang ◽

Kuao-John Young

Keyword(s):

Shell Length ◽

Safety Management ◽

Cylindrical Shells ◽

Burst Pressure ◽

Process Safety ◽

Finite Element Analyses ◽

Improved Method ◽

Displacement Effect ◽

Study Results ◽

Small Shell

For process safety management purposes, it is often required in industries to perform burst pressure calculations for pressurized equipment subjected to internal deflagrations. In predictions of burst pressures of vessels with short cylindrical shell sections, the stiffening effects of heads are often overlooked, which may lead to underestimated results. In this paper, a new improved method is proposed for predictions of burst pressures of thin cylindrical shells with small shell length to diameter ratios (L/D) at ambient temperature. The idea is to use the Svensson’s formula, modified by a factor that accounts for the effects of small L/D ratios, head types, and materials for more accurate predictions. Tables of such factors are developed based on study results from a series of elastic-plastic Finite Element Analyses including large displacement effect for different L/D ratios, thicknesses, materials, and head types. Some example problems are presented to validate the method.

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