Fluidic gates simulated with lattice Boltzmann method under different Reynolds numbers

© 2018 Elsevier B.V. Fluidic devices use fluid as a medium for information transfer and computation. Boolean values are represented by the presence of fluid jets in the input and output channels. Velocity of a fluid is one of the parameters determining Reynolds number of the flow. Reynolds number is a parameter that characterizes the behaviour of the flow: laminar, transient or turbulent. Using lattice Boltzmann method we study the behaviour of fluidic gates for various Reynolds numbers. On the designs of AND and OR gates we show the fluidic gates remain functional even for low Reynolds numbers, like 100. The gates designed can be cascaded into functional logical circuits

Microfluidics and Nanofluidics Handbook

The Microfluidics and Nanofluidics Handbook: Two-Volume Set comprehensively captures the cross-disciplinary breadth of the fields of micro- and nanofluidics, which encompass the biological sciences, chemistry, physics and engineering applications. To fill the knowledge gap between engineering and the basic sciences, the editors pulled together key individuals, well known in their respective areas, to author chapters that help graduate students, scientists, and practicing engineers understand the overall area of microfluidics and nanofluidics. Topics covered include Finite Volume Method for Numerical Simulation Lattice Boltzmann Method and Its Applications in Microfluidics Microparticle and Nanoparticle Manipulation Methane Solubility Enhancement in Water Confined to Nanoscale Pores Volume Two: Fabrication, Implementation, and Applications focuses on topics related to experimental and numerical methods. It also covers fabrication and applications in a variety of areas, from aerospace to biological systems. Reflecting the inherent nature of microfluidics and nanofluidics, the book includes as much interdisciplinary knowledge as possible. It provides the fundamental science background for newcomers and advanced techniques and concepts for experienced researchers and professionals

Bipolar electrochemistry for enrichment, separations, and membraneless electrochemically mediated desalination

Developments in bipolar electrochemistry for the simultaneous separation and enrichment of charged species and membraneless electrochemically mediated desalination (EMD) are presented. Each of these techniques requires an electrochemically generated local electric field within a microchannel and control over bulk fluid flow. In addition to bipolar electrochemical studies, investigations of ion depletion zone formation and EMD in a two-electrode microelectrochemical cell are presented. The dual-channel bipolar electrode (BPE) configuration is employed for the simultaneous enrichment and separation of anions and cations within a single microchannel at an ion depletion zone generated by buffer neutralization. Moreover, this experimental design is also used to generate an ion depletion zone and associated electric field gradient by Cl⁻ oxidation, where we demonstrate partial seawater desalination without the need for a physical membrane. Expanding upon the fundamentals of BPE focusing, we demonstrate proof-of-concept biomolecule separation and enrichment. Moreover, without the need for a direct external electrical connection, one hundred BPEs are operated simultaneously in parallel to enrich multiple analyte bands. Metal deposition at a BPE is used to mediate BPE focusing. Ion depletion zones arising from Cl⁻ oxidation are investigated by making axial electric field measurements while varying key experimental parameters affecting ion depletion zone formation, location, and strength. We investigate the capabilities of EMD by modifying the electrode design to increase the local electric field strength in an effort to increase the percentage of salt rejection. We also examine the possibility to lower, or even eliminate the electrical energy requirements of EMD by driving Cl⁻ oxidation photoelectrochemically. Lastly, on-line capacitively coupled contactless conductivity measurements are presented to rapidly and reliably quantify ion separation for EMD.Chemistr

Ein Kumulanten-Lattice-Boltzmann-Methode für LES von Dispersionsmikrosystemen

The production of nano-particles from larger aggregates is an important industrial process, especially for life-science products. In this thesis a micro-machined disperser developed by the DFG Research Group FOR 856 mikroPART is studied numerically by the cumulant lattice Boltzmann method. The aggregates are modeled as tracer particles with mass and drag coefficient. They record the history of the stresses and the relative velocity of the aggregates with respect to the fluid. For the evaluation of the velocities and stresses a compact second-order interpolation scheme is utilized. The tracer particles are implemented in a massively parallel multi-resolution lattice Boltzmann framework. The simulation of the disperser is validated against PIV and flow rate measurements from collaborators in the mikroPART Research Group. The drag coefficients of the aggregates are obtained by detailed simulations of synthetic aggregates in simple shear flow, elongational flow, and rotational flow. An empirical relation between the drag coefficient and the number of primary particles in the aggregate and its fractal dimensions is found and used in the tracer simulation of the disperser. Different measures of load on the aggregates are obtained by the simulation, for example maximal strain, exposure time to a certain strain, and relative velocity of the particles with respect to the surrounding fluid. It is assumed that ceramic aggregates break-up when they suffer a threshold strain rate. The distribution of the maximum strain rate seen by an aggregate can be condensed into a simple exponential cumulative probability distribution. Combined with a given threshold for the particle break-up this condensed model can also be used to determine the probability for aggregate breakage after n passages of the device. It is found that aggregates with realistic geometry (fractal number 1.85) usually have Stokes numbers smaller than one such that the load on these aggregates is dominated by the strain in the surrounding fluid. This is in contrast to spherical particles (fractal number 3) that have Stokes numbers in excess of one such that the load from their relative velocity with respect to the surrounding fluid is not negligible.Die Erzeugung von Nanopartikeln aus größeren Aggregaten ist ein wichtiger industrieller Prozess insbesondere in den Lebenswissenschaften. In dieser Dissertation wird ein von der DFG-Forschergruppe FOR 856 mikroPART entwickelter Dispergierkanal mit Hilfe der Kumulanten-Lattice-Boltzmann-Methode numerisch untersucht. Die Aggregate werden als Partikel mit Masse und Strömungswiderstandsbeiwert modelliert. Sie zeichnen den Verlauf der Spannungen und den der Relativgeschwindigkeit zwischen Partikel und Fluid über die Zeit auf. Die Geschwindigkeiten und Spannungen werden mit Hilfe eines kompakten Interpolationsschemas zweiter Ordnung berechnet. Die Partikelsimulation wird in ein massiv-paralleles Mehrskalen-Lattice-Boltzmann-Framework eingebettet. Zur Validierung wird die Simulation des Dispergierkanals mit PIV- und Flussratenmessungen verglichen, die von Projektpartnern innerhalb der mikroPART-Forschergruppe durchgeführt wurden. Die Strömungswiderstandsbeiwerte der Aggregate werden durch umfangreiche Simulationen synthetischer Aggregate in einfachen Scherströmungen, Dehnströmungen und Rotationsströmungen ermittelt. Es wird ein empirischer Zusammenhang zwischen dem Strömungswiderstandsbeiwert und der Anzahl der Partikel im Aggregat sowie dessen fraktaler Dimension aufgestellt. Dieser wird in der Partikelsimulation des Dispergierkanals verwendet. Die Simulation liefert verschiedene Masse für die Belastung der Aggregate, unter anderem die maximale Dehnung, die Einwirkzeit einer gegebenen Mindestdehnung und die Relativgeschwindigkeit der Partikel zu dem umgebenden Fluid. Es wird angenommen, dass keramische Aggregate brechen, wenn eine bestimmte Schwellendehnungsrate überschritten wird. Die Verteilung der maximalen von einem Aggregat erfahrene Dehnungsrate kann durch eine einfache exponentielle kumulative Wahrscheinlichkeitsverteilung ausgedrückt werden. In Verbindung mit dem Schwellenwert kann dieses reduzierte Modell zur Abschätzung der Wahrscheinlichkeit des Aggregatbruches nach n Durchquerungen des Dispergierkanals verwendet werden. Es wird festgestellt, dass bei realistischen Aggregatsgeometrien (fraktale Dimension 1.85) typischerweise Stokeszahlen kleiner als eins auftreten, so dass der dominierende Lastmechanismus die Dehnung durch das umgebende Fluid ist. Im Gegensatz dazu treten bei kugelförmigen Partikeln (fraktale Dimension 3) Stokeszahlen größer als eins auf. Daher ist die Last aus der Relativgeschwindigkeit zu dem umgebenden Fluid nicht vernachlässigbar

Optofluidic device for cytometric measurements and study of inertial focusing conditions in asymmetric serpentines

Presentem un dispositiu optofluídic amb capacitat per realitzar mesures citométriques. El dispositiu està compost dues zones de mesura en les que el senyal de fluorescència de cèl·lules tenyides s'obté mitjançant el bombeig òptic amb llum de 473 nm. Abans de ser mesurades, les cèl·lules són focalitzades mitjançant focalització hidrodinàmica. El senyal rebut és analitzat amb un algoritme propi per realitzar mesures de correlació dels senyals de cadascuna de les zones de mesura. Gràcies a aquests mètode, el dispositiu és capaç de distingir dos tipus de línies cel·lulars amb especificitat per a un determinat anticos. També presentem un estudi sobre el comportament de partícules esfèriques i rígides sota la influència d'efectes inercials en serpentins asimètrics. Aquests estudis, amb l'ajuda de simulacions, serveixen per revelar el comportament del fluid i de la partícula quan aquesta es troba focalitzada. Els resultats també revelen la predilecció per part de la partícula de moure's a través dels centres dels fluxos vorticials. La finalitat d'aquests resultats es la d'obtenir citómetres que, funcionant a través d'aquests mecanismes, siguin més eficients y fiables en les seves mesures.Presentamos un dispositivo optofluídico capaz de realizar medidas citométricas. El dispositivo contiene dos zonas de medida en las que la señal de fluorescencia de células teñidas se obtiene mediante el bombeo óptico con luz de 473 nm. Antes de su medida, las células son focalizadas mediante focalización hidrodinámica. La señal recibida es analizada con un algoritmo propio para realizar medidas de correlación de las señales de cada una de las zonas de medida. Gracias a este método, el dispositivo es capaz de distinguir dos tipos de líneas celulares con especificidad para un determinado anticuerpo. También presentamos un estudio acerca de el comportamiento de partículas esféricas y rígidas bajo la influencia de efectos inerciales en serpentines asimétricos. Estos estudios, con la ayuda de simulaciones, sirven para desengranar el comportamiento del fluido y de la particula cuando esta se encuentra focalizada. Los resultados también revelan la predilección por parte de las partículas de desplazarse a través de los centros de flujos vorticiales. La finalidad de estos resultados es la de obtener citómetros que, funcionando a través de estos mecanismos, sean más eficientes y fiables en sus medidas.An optofluidic device with cytometric capabilities is presented. The device consists of two interrogation regions from which the characteristic fluorescence signature of cell surface-labeled markers is obtained by means of 473 nm pumping. Prior to being measured, the cells are focused employing an hydrodynamical focusing scheme. The signal is treated with a custom algorithm to perform a correlation analysis between the signals from each interrogation region. With this method, the device is able o distinguish between two different cell line populations with antibody specificity. Additionally, studies regarding the behavior of rigid spherical particles under inertial focusing conditions in an asymmetric serpentine are presented. The dynamics of the flow field and the particle under focusing conditions is described employing simulation results. These studies also reveal the predilection of particles to move through the centerlines of the developed vortices. These results can be used to design more efficient and reliable cytometric devices that take advantage of inertial effects in conjunction with transverse flows

Advances in Optofluidics

Optofluidics a niche research field that integrates optics with microfluidics. It started with elegant demonstrations of the passive interaction of light and liquid media such as liquid waveguides and liquid tunable lenses. Recently, the optofluidics continues the advance in liquid-based optical devices/systems. In addition, it has expanded rapidly into many other fields that involve lightwave (or photon) and liquid media. This Special Issue invites review articles (only review articles) that update the latest progress of the optofluidics in various aspects, such as new functional devices, new integrated systems, new fabrication techniques, new applications, etc. It covers, but is not limited to, topics such as micro-optics in liquid media, optofluidic sensors, integrated micro-optical systems, displays, optofluidics-on-fibers, optofluidic manipulation, energy and environmental applciations, and so on

Quantum information dynamics

Presented is a study of quantum entanglement from the perspective of the theory of quantum information dynamics. We consider pairwise entanglement and present an analytical development using joint ladder operators, the sum of two single-particle fermionic ladder operators. This approach allows us to write down analytical representations of quantum algorithms and to explore quantum entanglement as it is manifested in a system of qubits.;We present a topological representation of quantum logic that views entangled qubit spacetime histories (or qubit world lines) as a generalized braid, referred to as a super-braid. The crossing of world lines may be either classical or quantum mechanical in nature, and in the latter case most conveniently expressed with our analytical expressions for entangling quantum gates. at a quantum mechanical crossing, independent world lines can become entangled. We present quantum skein relations that allow complicated superbraids to be recursively reduced to alternate classical histories. If the superbraid is closed, then one can decompose the resulting superlink into an entangled superposition of classical links. Also, one can compute a superlink invariant, for example the Jones polynomial for the square root of a knot.;We present measurement-based quantum computing based on our joint number operators. We take expectation values of the joint number operators to determine kinetic-level variables describing the quantum information dynamics in the qubit system at the mesoscopic scale. We explore the issue of reversibility in quantum maps at this scale using a quantum Boltzmann equation. We then present an example of quantum information processing using a qubit system comprised of nuclear spins. We also discuss quantum propositions cast in terms of joint number operators.;We review the well known dynamical equations governing superfluidity, with a focus on self-consistent dynamics supporting quantum vortices in a Bose-Einstein condensate (BEC). Furthermore, we review the mutual vortex-vortex interaction and the consequent Kelvin wave instability. We derive an effective equation of motion for a Fermi condensate that is the basis of our qubit representation of superfluidity.;We then present our quantum lattice gas representation of a superfluid. We explore aspects of our model with two qubits per point, referred to as a Q2 model, particularly its usefulness for carrying out practical quantum fluid simulations. We find that it is perhaps the simplest yet most comprehensive model of superfluid dynamics. as a prime application of Q2, we explore the power-law regions in the energy spectrum of a condensate in the low-temperature limit. We achieved the largest quantum simulations to date of a BEC and, for the first time, Kolmogorov scaling in superfluids, a flow regime heretofore only obtainably by classical turbulence models.;Finally, we address the subject of turbulence regarding information conservation on the small scales (both mesoscopic and microscopic) underlying the flow dynamics on the large hydrodynamic (macroscopic) scale. We present a hydrodynamic-level momentum equation, in the form of a Navier-Stokes equation, as the basis for the energy spectrum of quantum turbulence at large scales. Quantum turbulence, in particular the representation of fluid eddies in terms of a coherent structure of polarized quantum vortices, offers a unique window into the heretofore intractable subject of energy cascades

Advances in Hydraulics and Hydroinformatics Volume 2

This Special Issue reports on recent research trends in hydraulics, hydrodynamics, and hydroinformatics, and their novel applications in practical engineering. The Issue covers a wide range of topics, including open channel flows, sediment transport dynamics, two-phase flows, flow-induced vibration and water quality. The collected papers provide insight into new developments in physical, mathematical, and numerical modelling of important problems in hydraulics and hydroinformatics, and include demonstrations of the application of such models in water resources engineering

Manipulation of the Electrical Double Layer for Control and Sensing in a Solid State Nanopore

Nanopores have been explored with the goal of achieving non-functionalized, sub-molecular sensors, primarily with the purpose of producing fast, low-cost DNA sequencers. Because of the nanoscale volume within the nanopore structure, it is possible to isolate individual molecular and sub-molecular analytes. Nanopore DNA sequencing has remained elusive due to high noise levels and the challenge of obtaining single-nucleotide resolution. However, the complete electrical double layer within the nanopore is a key feature of fluid-nanopore interaction and has been neglected in previous studies. By exploring interactions with the electrical double layer in various nanopore systems, we characterize the material, electrical, and solution dependent properties of this structure and develop a new sensing technique. The overall goals of this project are development of a theoretically complete and useful model of the electrical double layer in a nanopore, development of a nanopore device capable of detecting and manipulating the electrical double layer, characterization of active nanofluidic control, and detection of molecular and double layer properties. By considering extensive numerical models along with experimental evaluation of the nanopore devices, we characterize the fluidic and sensor properties of the electrical double layer in a nanopore. The ability to interact with the electrochemical and structural properties of the fluid within a nanopore offers new avenues for molecular detection and manipulation. We find that the energetic balance between the nanopore surface potential and the distribution of charged species within the electrical double layer is the key relationship governing the operation of this type of device. A method of active control of the ionic conductance through the nanopore was developed, with complete gating and on-state modulation. A molecular sensing technique was developed by correlating changes to the electrochemical potential of the solution to the physical properties of molecular analytes. The theoretical and practical limits of the nanopore sensor were tested by implementing a new type of nanopore DNA sequencer. High accuracy DNA sequences were produced by combining the double layer potential and ionic current channels in parallel, along with extensive application of signal theory, digital signal processing, and machine learning techniques