A Free Gait Algorithm for Improved Mobility Control of Walking Machines

1995 ◽  
pp. 262-275
Author(s):  
Paul Alexandre ◽  
André Preumont
Keyword(s):  
Mobility Control ◽  
Walking Machines

scholarly journals Experimental investigation of the displacement flow mechanism and oil recovery in primary polymer flood operations

2021 ◽  
Vol 3 (5) ◽  
Author(s):  
Ruissein Mahon ◽  
Gbenga Oluyemi ◽  
Babs Oyeneyin ◽  
Yakubu Balogun
Keyword(s):  
Relative Permeability ◽  
Oil Recovery ◽  
Polymer Flooding ◽  
Mobility Control ◽  
List Type ◽  
Motor Oil ◽  
Flow Mechanism ◽  
Fractional Flow ◽  
Recovery Method ◽  
Polymer Flood

Abstract Polymer flooding is a mature chemical enhanced oil recovery method employed in oilfields at pilot testing and field scales. Although results from these applications empirically demonstrate the higher displacement efficiency of polymer flooding over waterflooding operations, the fact remains that not all the oil will be recovered. Thus, continued research attention is needed to further understand the displacement flow mechanism of the immiscible process and the rock–fluid interaction propagated by the multiphase flow during polymer flooding operations. In this study, displacement sequence experiments were conducted to investigate the viscosifying effect of polymer solutions on oil recovery in sandpack systems. The history matching technique was employed to estimate relative permeability, fractional flow and saturation profile through the implementation of a Corey-type function. Experimental results showed that in the case of the motor oil being the displaced fluid, the XG 2500 ppm polymer achieved a 47.0% increase in oil recovery compared with the waterflood case, while the XG 1000 ppm polymer achieved a 38.6% increase in oil recovery compared with the waterflood case. Testing with the motor oil being the displaced fluid, the viscosity ratio was 136 for the waterflood case, 18 for the polymer flood case with XG 1000 ppm polymer and 9 for the polymer flood case with XG 2500 ppm polymer. Findings also revealed that for the waterflood cases, the porous media exhibited oil-wet characteristics, while the polymer flood cases demonstrated water-wet characteristics. This paper provides theoretical support for the application of polymer to improve oil recovery by providing insights into the mechanism behind oil displacement. Graphic abstract Highlights The difference in shape of relative permeability curves are indicative of the effect of mobility control of each polymer concentration. The water-oil systems exhibited oil-wet characteristics, while the polymer-oil systems demonstrated water-wet characteristics. A large contrast in displacing and displaced fluid viscosities led to viscous fingering and early water breakthrough.

COVID-19 Certificates as a New Form of Mobility Control

2021 ◽  
pp. 1-8
Author(s):  
Jouni HÄKLI
Keyword(s):  
Air Traffic ◽  
Mobility Control ◽  
Border Crossings ◽  
Mobile Populations ◽  
Global Mobility ◽  
Travel Restrictions ◽  
Place Of Origin ◽  
New Form ◽  
International Border

The global volume of travel has grown steadily for decades and hence the border closures and travel restrictions in response to COVID-19 have created an unforeseen impact on the number of international border crossings. In air traffic alone the data show a striking 75.6% decrease in the number of scheduled international passengers. We might hasten to think that the strict travel restrictions due to the COVID-19 crisis have in principle treated mobile populations equally – for once we have all been banned from travelling. We could even consider the recent initiatives to introduce “vaccination certificates” as a fair and democratic way to reintroduce safe international travelling. In reality, the idea of a COVID-19 certificate is but a new layer in the broader landscape of highly uneven global mobility where travellers’ citizenship and place of origin truly matter. This article discusses some of the major inequalities embedded in the global mobility regime and argues that the idea of the COVID-19 certificate as an equaliser remains completely disconnected from these underlying realities. To conclude, the article discusses problems related to uneven access to digital travel documents, such as the proposed COVID-19 certificate.

Borders as penal transplants: Control of territory, mobility and illegality in West Africa

2021 ◽  
pp. 136248062199545
Author(s):  
Eva Magdalena Stambøl
Keyword(s):  
West Africa ◽  
Social Control ◽  
Crime Control ◽  
Border Studies ◽  
Border Security ◽  
Mobility Control ◽  
Spatial Awareness ◽  
Control Order ◽  
Political Technology ◽  
Geographical Scope

This article explores an increasingly significant trend in crime and mobility control that has received scant criminological attention: border externalization, specifically scrutinizing land border security-building by international actors in West Africa. Going beyond the usual focus on migration in border studies, it develops a criminologically grounded theorization of the border as a political technology of crime control and its relationship to the state. This is done by arguing that borders, theorized as ‘penal transplants’ embodying specific (western) visions of state, political power, social control/order and territoriality, are transformed and often distorted when performed in ‘heterarchical’ contexts in the global South. Further, empirically based concepts from ‘the periphery’ are suggested to enrich border criminology, broadening its geographical scope and spatial awareness.

CO2 EOR: Nanotechnology for Mobility Control Studied

2012 ◽  
Vol 64 (07) ◽  
pp. 28-31 ◽  
Author(s):  
Sinisha (Jay) Jikich
Keyword(s):  
Mobility Control ◽  
Co2 Eor
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