Diffusion layer formation drives zone migration in travelling wave electrophoresis.

We integrated a portable, disposable, simple to fabricate, and highly effective polymeric microfluidic viral sample concentration device to the Interferometric Reflectance Imaging Sensor (IRIS) to increase infectious disease diagnostic speed and sensitivity at the point-of-care.

Radiation Belt Storm Probes: A New Mission for Space Weather Forecasting

Mass transport of different species plays a crucial role in electrochemical conversion of CO2 due to the solubility limit of CO2 in aqueous electrolytes. In this study, we investigate the transport of CO2 and other ionic species through the electrolyte and the membrane, and its impact on the scale-up process of HCOO−/HCOOH formation. The mass transport of ions to the electrode and the membrane is modelled at constant current density. The mass transport limitations of CO2 on the formation of HCOO−/HCOOH is investigated at different pressures ranges from 5–40 bar. The maximum achievable partial current density of formate/formic acid is increased with increasing CO2 pressure. We use an ion exchange membrane model to understand the ion transport behaviour for both the monopolar and bipolar membranes. The cation exchange (CEM) and anion exchange membrane (AEM) model show that ion transport is limited by the electrolyte salt concentrations. For 0.1 M KHCO3, the AEM reaches the limiting current density more quickly than the CEM. For the BPM model, ion transport across the diffusion layer on either side of the BPM is also included to understand the concentration polarization across the BPM. The model revealed that the polarization losses across the bipolar membrane depend on the pH of the electrolyte used for the CO2 reduction reaction (CO2RR). The polarization loss on the anolyte side decreases with an increasing pH, while, on the cathode side, it increases with increasing catholyte pH. With this combined model for the electrode reactions and the membrane transport, we are able to account for the various factors influencing the polarization losses in the CO2 electrolyzer. To complete the analysis, we simulated the full cell polarization curve and fitted with the experimental data.

Direct force measurements between negatively charged silica particles in the presence of a like-charged strong polyelectrolyte were carried out with an atomic force microscope. The force profiles can be quantitatively interpreted as a superposition of depletion and double-layer forces. The depletion forces are modeled with a damped oscillatory profile, while the double-layer forces with the mean-field Poisson-Boltzmann theory for a strongly asymmetric electrolyte, whereby an effective valence must be assigned to the polyelectrolyte. This effective valence is substantially smaller than the bare valence due to ion condensation effects. The unusual aspect of the electrical double layer in these systems is the exclusion of the like-charged polyelectrolyte from the vicinity of the surface, leading to a strongly nonexponential diffuse ionic layer that is dominated by counterions and has a well-defined thickness. As the oscillatory depletion force sets in right after this layer, this condition can be used to predict the phase of the oscillatory depletion force.

This textbook is written for use in any university course related to the physics of waves, wave theory, and electromagnetic waves in departments such as Physics, Electrical Engineering, Mechanical Engineering, Civil Engineering, and Mathematics. The only prerequisite knowledge is a course in calculus. This textbook provides a unified treatment of waves that either occur naturally or can be excited and propagated in various media. This includes both longitudinal and transverse waves. The book covers both mechanical and electrical waves, which are normally covered separately due to their differences in physical phenomena. This text focuses more on the similarities of all waves, mechanical orelectromagnetic, and therefore allows the reader to formulate a unified understanding of wave phenomena in its totality. This second edition contains extensive updates and advances in the understanding of wave phenomena since the publication of the first edition (1985). Numerous additional problems are now present and several chapters have been rewritten and combined. This is the first book in the Mario Boella Series on Electromagnetism in Information and Communication. Key features include: A unified treatment of wave phenomena; Numerical techniques using MATLAB; Both mechanical and electrical waves are described; Necessary mathematics required to understand the material summarized within; Only prerequisite is an introductory course in calculus.

DNA generates a longitudinal wave that propagates in the direction of the magnetic field vector. Computed frequencies from the structure of DNA agree with those of the predicted biophoton radiation. The optimization of efficiency by minimizing the conduction losses leads to the double-helix structure of DNA. The vortex model of the magnetic scalar wave not only covers many observed structures within the nucleus perfectly, but also explains the hyperboloid channels in the matrix when two cells communicate with each other. Potential vortexes are an essential component of a scalar waves, as discovered in 1990. The basic approach for an extended field theory was confirmed in 2009 with the discovery of magnetic monopoles. For the first time, this provides the opportunity to explain the physical basis of life not only from the biological discipline. Nature covers the whole spectrum of known scientific fields of research, and interdisciplinary understanding is required to explain its complex relationships. The characteristics of the potential vortex are significant. With its concentration effect, it provides for miniaturization down to a few nanometers, which allows enormously high information density in the nucleus. With this first introduction of the magnetic scalar wave, it becomes clear that such a wave is suitable to use genetic code chemically stored in the base pairs of the genes and electrically modulate them, so as to "piggyback" information from the cell nucleus to another cell. At the receiving end, the reverse process takes place and the transported information is converted back into a chemical structure. The necessary energy required to power the chemical process is provided by the magnetic scalar wave itself.

In the frame of this contribution, two electrochemical flow cells developed for scanning electrochemical microscopy (SECM) are presented. Forced convection was generated by a flow of the mediator solution through the flow cells. A description of the mandatory design aspects of the experimental flow cell setups is included. Using a macroscopic working electrode as a substrate electrode, forced convection leads to the formation of a stable diffusion layer during amperometric experiments in contrast to a growing diffusion layer in quiescent solution. To characterize the effects of forced convection, the diffusion layer around a platinum substrate electrode integrated into the cells was investigated utilizing chronoamperometric measurements and hydrodynamic SECM imaging in amperometric substrate generation-tip collection (SG/TC) mode. Both methods proved the stability and the time-independency of the diffusion layer. Mathematical simulations using COMSOL Multiphysics were computed to investigate the flow profile generated by the flowing mediator solution in the relevant region close to the substrate electrode. In summary, two different electrochemical flow cells for SECM were developed and characterized. Both cell designs enabled steady-state diffusion layer characteristics at a macroscopic substrate electrode offering interesting possibilities such as time-independent measurements in the context of the SG/TC mode.

Insights into the microstructure, property, and metallurgy mechanism of 93WNiFe/steel diffusion bonding joint utilizing a NiFeW solid solution interlayer

The collective interactions in a four-component mixture of charged particles, the ions whose dissociation generates the charge of the particles, and the ions of a binary electrolyte are described by a symmetrized Poisson–Boltzmann (SPB) equation. The ion excesses in the diffuse layer are considered to be bound to the particles. The computations show that the binding numbers in the SPB approximation can differ considerably from those obtained on the basis of the conventional Poisson–Boltzmann equation. The structure of the mixture described by the SPB equations is examined and it is found that there are conditions under which the collective interactions generate and effective attraction among particles.

The Interplay of Diffusional and Electrophoretic Transport Mechanisms of Charged Solutes in the Liquid Film Surrounding Charged Nonporous Adsorbent Particles Employed in Finite Bath Adsorption Systems

A conceptual description of material transport through a liquid phase diffusion layer during pulse and reverse pulse current plating is provided. The formation of a dual diffusion layer, with an inner pulsating diffusion layer and an outer, unaffected diffusion layer is described. The quantification of these two layers using limiting current experiments and theoretical analysis is discussed. Based on these material transfer phenomena, the basis of selection of pulse parameters is shown. The step by step approach to use these mass transfer equations as a set of design rules, and their subsequent use in a graph to select pulse and reverse pulse parameters is described.

The interfacial interaction between Cr thin films and multi-component oxide glasses has been observed by means of high spatial resolution electron energy loss spectroscopy. Besides a partially oxidized Cr thin layer, a ∼5nm wide Cr diffusion layer is seen. Chromium oxidation at the interface results from the difference between the heats of oxide formation. Ion exchange between Cr2+ and alkaline earth ions then causes the formation of the diffusion layer. The electronic states of the Cr in this diffusion layer are different from that in the oxidized layer. Strong interaction between Cr and O in the diffusion layer suggests that such a layer could be responsible for the formation of a strong Cr/glass interface

In a magnetic single component development system of electrophotography, toner particles are formed into a thin layer by a contact blade, which also makes toner particles charged. This particle layer is important for quality of output images. However, the particle layer is sometimes not formed properly by some reasons, such as, condensed particles which stay in the nip between the blade and a sleeve. In an extreme case, toner particles are not provided normally and the shortage of the toner in the development area makes the output image quality poor. To clarify a mechanism of the particle layer formation in the development system, Distinct Element Method is applied and an roll of a blade pressure in layer formation is analyzed. The simulation result suggests that too low blade pressure does not make an uniform layer and there is a proper pressure range for the uniform layer formation.

Models and microfluidic experiments are presented of an electrophoretic separation technique in which charged particles whose mobilities exceed a tunable threshold are trapped between the crests of a longitudinal electric wave traveling through a stationary viscous fluid. The wave is created by applying periodic potentials to electrode arrays above and below a microchannel. Predicted average velocities agree with experiments and feature chaotic attractors for intermediate mobilities.

We show that ~1 Hz magnetic compressional waves observed in Mercury's inner magnetosphere could be interpreted as ion‐Bernstein waves in a moderate proton beta ~0.1 plasma. An observation of a proton distribution with a large planetary loss cone is presented, and we show that this type of distribution is highly unstable to the generation of ion‐Bernstein waves with low magnetic compression. Ray tracing shows that as these waves propagate back and forth about the magnetic equator; they cycle between a state of low and high magnetic compression. The group velocity decreases during the high‐compression state leading to a pileup of compressional wave energy, which could explain the observed dominance of the highly compressional waves. This bimodal nature is due to the complexity of the index of refraction surface in a warm plasma whose upper branch has high growth rate with low compression, and its lower branch has low growth/damping rate with strong compression. Two different cycles are found: one where the compression maximum occurs at the magnetic equator and one where the compression maximum straddles the magnetic equator. The later cycle could explain observations where the maximum in compression straddles the equator. Ray tracing shows that this mode is confined within ±12° magnetic latitude which can account for the bulk of the observations. We show that the Doppler shift can account for the difference between the observed and model wave frequency, if the wave vector direction is in opposition to the plasma flow direction. We note that the Wentzel‐Kramers‐Brillouin approximation breaks down during the pileup of compressional energy and that a study involving full wave solutions is required.