Separation of suspended particles by arrays of obstacles in microfluidic devices

The stochastic transport of suspended particles through a periodic pattern of obstacles in microfluidic devices is investigated by means of the Fokker-Planck equation. Asymmetric arrays of obstacles have been shown to induce the continuous separation of DNA molecules of different length. The analysis presented here of the asymptotic distribution of particles in a unit cell of these systems shows that separation is only possible in the presence of a driving force with a non-vanishing normal component at the surface of the solid obstacles. In addition, vector separation, in which different species move, in average, in different directions within the device, is driven by differences on the force acting on the various particles and not by differences in the diffusion coefficient. Monte-Carlo simulations performed for different particles and force fields agree with the numerical solutions of the Fokker-Planck equation in the periodic system

Determination of the zeta potential for highly charged colloidal suspensions

We compute the electrostatic potential at the surface, or zeta potential $\zeta$, of a charged particle embedded in a colloidal suspension using a hybrid mesoscopic model. We show that for weakly perturbing electric fields, the value of $\zeta$ obtained at steady state during electrophoresis is statistically indistinguishable from $\zeta$ in thermodynamic equilibrium. We quantify the effect of counterions concentration on $\zeta$. We also evaluate the relevance of the lattice resolution for the calculation of $\zeta$ and discuss how to identify the effective electrostatic radius.Comment: 8 pages, 3 figures with 2 panel

Natural Succession in Planted Conifer Forests in Eastern New York

During the summer of 1954 the author was privileged to conduct floristic and ecological studies on the Edmund Niles Huyck Preserve, located near Rensselaerville, in Albany County, New York. This Preserve is about 470 acres in size and centers about two bodies of water. The larger is called Lake Myosotis, after the wild forget-me-not, Myosotis laxa Lehm, which is abundant along its margin. The Preserve was established in 1931, in memory of Edmund Niles Huyck, by his widow and friends, and the majority of it has been under strict and complete protection from disturbance since that time. Parts of the Preserve have been without disturbances (principally logging and grazing) since the latter part of the 19th century

McClellan\u27s War

The Controversial Commander Little Mac, Lincoln, and the Army of the Potomac Bashers beware! Your days of unbridled freedom have come to an end; you can no longer say anything, use the sources carelessly, or announce irrational conclusions. White knights are not rescuing the ...

The Sword of Lincoln:The Army of the Potomac

Comprehensive combat history Wert takes a stab with single volume If an award is available to persons who undertake historical tasks of extraordinary difficulty, Jeff Wert should have it. His one-volume history of the Army of the Potomac, in the face of the daunting amount of ma...

Alien Registration- Murphy, Russel H. (Enfield, Penobscot County)

https://digitalmaine.com/alien_docs/10148/thumbnail.jp

Evaluation of Dimethyl Anthranilate as a Nontoxic Starling Repellent for Feedlot Settings

Few objective estimates are available, but starling (Sturnus uulgaris) and, sometimes, blackbird (e.g., Agelaius phoeniceus) depredations at feedlots are considered serious economic problems (Besser et al. 1967, 1968; Feare 1975, 1980; Stickley 1979; Twedt and Glahn 1982). Losses may result either from feed contamination and disease transmission or, more likely, from feed consumption (Besser et al. 1968; Russell 1975; Twedt and Glahn 1982). These problems are exacerbated by the use of complete diets (Rickaby 1978) which are presented in open troughs to which starlings have access. Feare and Wadsworth (1981) have shown that these birds can take up to 9% of the high protein fraction of the diet, thus depriving cattle of their high energy source and altering the composition of the entire ration. Efforts to control problem birds at feedlots have focused mainly on attempts to trap or kill birds with mechanical devices or chemical agents (Besser et al. 1967; Bogadich 1968; Levingston 1967; Westetal.1967; Feareetal.1981). These approaches, however, fail to create a suboptimal environment for avian feeding activity, and birds rapidly reinfest feedlots when control measures are relaxed (Twedt and Glahn 1982). Additional problems arise when lethal chemicals; such as Starlicide (1% C-chloro-p-toludine hydrochloride on poultry pellets) are used, including: (1) potential primary and secondary hazards to nontarget animals (e.g., Cunningham, 1979), (2) bait aversion by target birds, (3) expense and labor in prebaiting, baiting and monitoring (Glahn 1981) and (5) rather short-term effectivenses when large numbers of birds are in the area (Feare et al. 1981)

Velocity fluctuations and hydrodynamic diffusion in sedimentation

We study non-equilibrium velocity fluctuations in a model for the sedimentation of non-Brownian particles experiencing long-range hydrodynamic interactions. The complex behavior of these fluctuations, the outcome of the collective dynamics of the particles, exhibits many of the features observed in sedimentation experiments. In addition, our model predicts a final relaxation to an anisotropic (hydrodynamic) diffusive state that could be observed in experiments performed over longer time ranges.Comment: 7 pages, 5 EPS figures, EPL styl

ELAN as flexible annotation framework for sound and image processing detectors

Annotation of digital recordings in humanities research still is, to a largeextend, a process that is performed manually. This paper describes the firstpattern recognition based software components developed in the AVATecH projectand their integration in the annotation tool ELAN. AVATecH (AdvancingVideo/Audio Technology in Humanities Research) is a project that involves twoMax Planck Institutes (Max Planck Institute for Psycholinguistics, Nijmegen,Max Planck Institute for Social Anthropology, Halle) and two FraunhoferInstitutes (Fraunhofer-Institut für Intelligente Analyse- undInformationssysteme IAIS, Sankt Augustin, Fraunhofer Heinrich-Hertz-Institute,Berlin) and that aims to develop and implement audio and video technology forsemi-automatic annotation of heterogeneous media collections as they occur inmultimedia based research. The highly diverse nature of the digital recordingsstored in the archives of both Max Planck Institutes, poses a huge challenge tomost of the existing pattern recognition solutions and is a motivation to makesuch technology available to researchers in the humanities

Correlated dynamics of inclusions in a supported membrane

The hydrodynamic theory of heterogeneous fluid membranes is extended to the case of a membrane adjacent to a solid substrate. We derive the coupling diffusion coefficients of pairs of membrane inclusions in the limit of large separation compared to the inclusion size. Two-dimensional compressive stresses in the membrane make the coupling coefficients decay asymptotically as $1/r^2$ with interparticle distance $r$. For the common case, where the distance to the substrate is of sub-micron scale, we present expressions for the coupling between distant disklike inclusions, which are valid for arbitrary inclusion size. We calculate the effect of inclusions on the response of the membrane and the associated corrections to the coupling diffusion coefficients to leading order in the concentration of inclusions. While at short distances the response is modified as if the membrane were a two-dimensional suspension, the large-distance response is not renormalized by the inclusions.Comment: 15 page