Magnetic Particle Handling In Microfluidic Systems

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In this work, we extend our previous studies (Singh et al 2023, Nucl. Fusion 63, 086029; Singh et al 2024, Nucl. Fusion 64, 106005) by performing global δf electromagnetic gyrokinetic simulations including collisions using the ORB5 particle-in-cell (PIC) code, spanning the plasma from magnetic axis to separatrix. The analysis focuses on ion temperature gradient (ITG) and trapped electron mode (TEM) turbulence in both linear and nonlinear regimes for experimentally relevant profiles and parameters of the ADI

Since the discovery of two-dimensional magnetic materials in 2017, an uncharted territory has opened within the field of spintronics, drawing intense interest from both experimental and computational research. From a computational perspective, studying magnetic materials requires addressing several challenges: achieving accurate simulations of localized electrons, identifying the ground state magnetic ordering, determining the parameters of effective Hamiltonians, such as Hubbard parameters or exchange inte

Electrodeposition has been widely used to develop micro-mechanical devices because it offers high dimensional accuracy, flexibility, and relatively low cost. In devices such as mechanical watches, micro-components are required to be made from non-magnetic, hard, and wear-resistant materials. Copper is a common non-magnetic material used in the electrodeposition process, but its intrinsic low strength and soft mechanical behavior limit its use in such applications. These limitations can be overcome by devel

During this semester’s project, an alternative process for manufacturing microfluidic channels was tested. Silicon wafers were processed to determine whether silicon-tosilicon bonding could be used to reduce the number of steps in the production process. To achieve this, different combinations of surface treatment and bonding temperature were tested to observe their effect on the process. Some wafers underwent HF cleaning prior to bonding, while others did not. Bonding temperatures ranging from 300°C to 450

This study investigates the maximum achievable received power for an implantable receiver deeply implanted in the human body, considering both electric dipole and magnetic loop sources with millimeter-scale dimensions. The analysis incorporates safety constraints related to the specific absorption rate. A full-wave simulation approach is employed for the case study. The results demonstrate that the proposed method can be applied to high-frequency simulations, where a received power of 0.16 W is achievable a

Common metal additive manufacturing technologies require intensive energy sources such as lasers to achieve the melting and bonding of a metallic feedstock. This leads to a sizeable carbon footprint especially for reflective materials such as aluminium. Moreover, it induces complex and turbulent melt pool dynamics leading to stochastic defect formation mechanisms that are hence difficult to suppress. We aim to propose an alternative approach similar to what is now practised on a large scale with thermoplast

Research into mesoscopic magnetic systems, which incorporate magnetic elements with dimensions ranging from a few nm up to a few 10s of micrometer, has been spurred on by the developments in their fabrication, characterisation, and control. Electron beam and optical lithography are key methods for their fabrication because they can be used to create tailor- made planar arrangements of elements or more complex layered structures. These can be further transformed into high quality three-dimensional mesoscale

We present magnetization and Se-77 Nuclear Magnetic Resonance (NMR) measurements in single crystals of the magnetoelectric compound Cu2OSeO3. The temperature and field dependence of the magnetization suggest a ferrimagnetic ordering at T-c similar or equal to 60 K in a 3up-1down configuration. The easy axis of the magnetization is along the [100] crystallographic direction. The Se-77 NMR line shape data collected at 14.09 T are consistent with the symmetries imposed by the cubic P2(1)3 space group in the te

In this contribution we present our work on filtration of plasma from whole blood in a polymer-based microfluidic system. The absorption of pathogens was found to be low; therefore our system is valid for clinical trials. The blood filtration element is capable of extracting 8–15μL volume of plasma from 100μL of whole blood in 7 minutes.

The existence of a critical pressure gradient needed to drive the interchange instability is experimentally demonstrated in the simple magnetized torus TORoidal Plasma EXperiment [A. Fasoli et al., Phys. Plasmas 13, 055902 (2006)]. This gradient is reached during a scan in the neutral gas pressure pn. Around a critical value for pn, depending on the magnetic configuration and on the injected rf power, a small increase in the neutral gas pressure triggers a transition in the plasma behavior. The pressure pro

Measuring the nuclear magnetic resonance spectra of low-gamma heteronuclei such as N-15 constitutes an important analytical tool for the characterization of molecular structure and dynamics. The reduced resonance frequencies and magnetic moments of these heteronuclei, however, make the sensitivity of this kind of spectroscopy inherently lower than that of comparable H-1 NMR observations. A well-known solution to this sensitivity problem is indirect detection: a 2D NMR technique capable of enhancing the sens

There has been a recent trend towards the miniaturization of analytical tools, but what are the advantages of microfluidic devices and when is their use appropriate? Recent advances in the field of micro-analytical systems can be classified according to instrument performance (which refers here to the desired property of the analytical tool of interest) and two important features specifically related to miniaturisation, namely reduction of the sample volume and the time-to-result. Here we discuss the contri

The ring cyclotron of the Paul Scherrer Institute (PSI) accelerates an intense proton beam from 72MeV up to 590MeV. This happens in four cavities of very high quality factor, oscillating in the fundamental mode. The beam can excite parasitic oscillation modes (HOMs), because of its time structure. Measurements showed that their field can leak out into the vacuum chamber. Until now, there is no tool available to predict the potentially harmful effect of these HOMs onto the beam operation of the cyclotron. It

We propose an approach for magnetic microbead transport in microfluidic channels over long-range distances using an array of simple planar coils. The latter are placed in a uniform static magnetic field, the role of which is to impose a permanent magnetic moment to the microbeads. The very small magnetic field gradient of a simple planar coil is then sufficient to displace the microbeads. The long-range displacement is assured by arranging adjacent coils in the array with spatial overlap in a three-phase ac

The quasi-1D S = 1/2 antiferromagnet CuGeO3 undergoes a spin-Peierls transition to a dimerised singlet quantum ground state, with S = 1 carrying pairs of domain walls as elementary excitations. Applying a large magnetic field, the domain walls-solitons-can be condensed into the ground state, forming a static incommensurate soliton lattice, which has been investigated by neutron scattering. The static soliton structure was found to be in good accordance to field theoretical and numerical calculations, while

A set of new technologies to fabricate microchannels using photosensitive polymer materials is presented. They are based on the use of polymers, hereafter called photopolymers, that are cured with UV light under a mask exposure. The basic material is ail epoxy-based photopolymer which can be patterned in thick layers with high aspect ratio.-Several process variations for making multilayered channel network are described and discussed. a) a process based on the refill of channels with a non-sensitive polymer

The correlation between Si-29 chemical shifts and Si-O-Si bond angles in SiO2 is determined within density-functional theory for the full range of angles present in vitreous silica. This relation closely reproduces measured shifts of crystalline polymorphs. The knowledge of the correlation allows us to reliably extract from the experimental NMR spectrum the mean (151 degrees) and the standard deviation (11 degrees) of the Si-O-Si angular distribution of vitreous silica. In particular, we show that the Mozzi

We consider a single-band approximation to the random Schr6dinger operator in an external magnetic field. The random potential consists of delta functions of random strengths situated on the sites of a regular two-dimensional lattice. We characterize the entire spectrum of this Hamiltonian when the magnetic field is sufficiently high. We show that the whole spectrum is pure point, the energy coinciding with the first Landau level in the absence of a random potential being infinitely degenerate, while the ei

Magnetic Particle Handling In Microfluidic Systems

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Electromagnetic gyrokinetic simulation of drift wave turbulence in ADITYA-U with collisions

Two-dimensional magnetic materials from first principles

Electrochemical deposition of composite materials: unravelling the process-structure-property nexus

Fabrication of microfluidic channels using Si-Si bonding

A Suitable Metric for Maximum Received Power of Deep-Tissue Implantable Devices

Magnetic Field-Assisted Direct Liquid Metal Deposition

Mesoscopic magnetic systems: From fundamental properties to devices

Magnetic properties of the magnetoelectric compound Cu2OSeO3: Magnetization and Se-77 NMR study

Clinical Validation of a Blood Filtration Element for Plasma Separation at the Point of Care

Observation of a critical pressure gradient for the stabilization of interchange modes in simple magnetized toroidal plasmas

Sensitivity Enhancement in 1D Heteronuclear NMR Spectroscopy via Single-Scan Inverse Experiments

Why the move to microfluidics for protein analysis?

Beam-cavity interactions in high power cyclotrons

Long-range transport of magnetic microbeads using simple planar coils placed in a uniform magnetostatic field

The field-induced soliton phase of CuGeO3

Photo-polymer microchannel technologies and applications

Si-O-Si bond-angle distribution in vitreous silica from first-principles Si-29 NMR analysis

The nature of the spectrum for a Landau hamiltonian with delta impurities