Departing from the classical Buckley-Leverett theory for two-phase immiscible flows in porous media, a reduced evolution equation for the water-oil displacement front is formulated and studied numerically. The reduced model successfully reproduces the basic features of the finger-forming dynamics observed in recent direct numerical simulations. PACS numbers: 47.20.Gv, 47.20.Ky, 47.20.Ma

The hydrostatic actuation system based on linear actuators improves the complex piston force and long transmission path of traditional electro-hydrostatic actuator (EHA). However, new nonlinear factors in direct-driven are introduced into system, which present challenges to modeling control. To improve accuracy performance prediction, this paper analyzed working characteristics an electromagnet...

In the last decade, displacement-based seismic design procedures have been recognised to be effective alternatives to force-based design (FBD) methods. Indeed, displacement based design (DBD) may allow the structural engineer to get more realistic predictions of local and global deformations of the structure, and hence damage, under design earthquakes. This facilitates the achievement of perfor...

This paper presents tracking control performances of a piezostack direct drive valve (PDDV) operating at various temperatures. As a first step, a spool valve and valve system are designed to be operated by the piezoactuator. In this study, the stacked piezoelectric actuator, which is lead–zirconate–titanate (PZT) ceramic is used for control of spool displacement. An aerogel is used for heat ins...

Enveloped virus release is driven by poorly understood proteins that are functional analogs of the coat protein assemblies that mediate intracellular vesicle trafficking. We used differential electron density mapping to detect membrane integration by membrane-bending proteins from five virus families. This demonstrates that virus matrix proteins replace an unexpectedly large portion of the lipi...

Significant research efforts have been devoted in recent years to the development of displacement-based seismic design methodologies, recognizing the shortcomings of traditional, code-specified force-based design procedures. Recent advances in direct displacement-based seismic design of columns rely on the estimates of yield curvature for the determination of seismic design forces to satisfy th...

Draga Pihler-Puzović1,†, Anne Juel1, Gunnar G. Peng2, John R. Lister2 and Matthias Heil3 1Manchester Centre for Nonlinear Dynamics and School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK 2Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA, UK 3School of Mathematics and Manchester Cent...

Reproductive isolation can evolve between species as a byproduct of adaptation to different niches, through reinforcement, and by direct selection on mating preferences. We investigated the potential role of direct selection in the reproductive isolation between sympatric species of threespine sticklebacks. Each sympatric pair consists of a small-bodied limnetic species and large-bodied benthic...

THE APPLICATION of physical principles to problems inherent in taking and recording ballistocardiograms has resulted, not only in greater understanding of the genesis of the record, but also in several important advances in other directions. Thus, under the impact of this analysis a new type of instrument, the ultra-low frequency ballistocardiograph, has been reintroduced and the older high-fre...