Qualitative Analysis of Magnetic Moment in BaxTiO3 - Ni xFe3- xO4 Nanocomposite Synthesized by Novel low Temperature Technique

A novel low temperature preparation technique (<500ºC) is employed for synthesizing nanoscale Barium Titanate -Nickel ferrite composites, where the particle size is controllable. Two different ratios of hard and soft site composites (BTO-NFO 80:20, BTO-NFO 70:30) are synthesized and characterized to study their unique structural, morphological and magnetic properties. The structural refinement studies using XRD data showed 43 % of hard phase (anorthic structure) and 57% of soft phase (Cubic Structure) for BTO-NFO 80:20 and similarly 76% of hard phase and 24% of soft phase in the BTO-NFO 70:30 composite respectively. The SEM and EDAX are used to identify smaller particles of 10 nm using histogram and their sample purity. The VSM analysis at room temperature shows superparamagnetic behavior within the soft ferro magnet with maximum retentivity 2.39 emu/g and saturation magnetization, 10.71 emu/g stating that the composites can be used for various biological applications like drug delivery, hyperthermia, MRI, etc. The ratio Mr/Ms is much less than 0.5, which states that multidomain grains or single domains are formed and the particle interaction is by magneto-static interaction confirming its superparamagnetic nature.

Design and Numerical Simulation of Biomimetic Structures to Capture Particles in a Microchannel

The study of separating different sizes of particles through a microchannel has been an interest in recent years and the primary attention of this study is to isolate the particles to the specific outlets. The present work highly focuses on the design and numerical analysis of a microchip and the microparticles capture using special structures like corrugated dragonfly wing structure and cilia walls. The special biomimetic structured corrugated wing is taken from the cross-sectional area of the dragonfly wing and cilia structure is obtained from the epithelium terminal bronchioles to the larynx from the human body. Parametric studies were conducted on different sizes of microchip scaled and tested up in the range between 2–6 mm and the thickness was assigned as 80 µm in both dragonfly wing structure and cilia walls. The microflow channel is a low Reynolds number regime and with the help of the special structures, the flow inside the microchannel is pinched and a sinusoidal waveform pattern is observed. The pinched flow with sinusoidal waveform carries the particles downstream and induces the particles trapped in desired outlets. Fluid particle interaction (FPI) with a time-dependent solver in COMSOL Multiphysics was used to carry out the numerical study. Two particle sizes of 5 µm and 20 µm were applied, the inlet velocity of 0.52 m/s with an inflow angle of 50° was used throughout the study and it suggested that: the microchannel length of 3 mm with corrugated dragonfly wing structure had the maximum particle capture rate of 20 µm at the mainstream outlet. 80% capture rate for the microchannel length of 3 mm with corrugated dragonfly wing structure and 98% capture rate for the microchannel length of 2 mm with cilia wall structure were observed. Numerical simulation results showed that the cilia walled microchip is superior to the corrugated wing structure as the mainstream outlet can conduct most of the 20 µm particles. At the same time, the secondary outlet can laterally capture most of the 5 µm particles. This biomimetic microchip design is expected to be implemented using the PDMS MEMS process in the future.

FEM ANALYSIS OF ENERGY LOSS DUE TO WAVE PROPAGATION FOR MICRO-PARTICLE IMPACTING SUBSTRATE WITH HIGH VELOCITIES

The impact between particles and material surface is a micro-scaled physical phenomenon found in various technological processes and in the study of the mechanical properties of materials. Design of materials with desired properties is a challenging issue for most industries. And especially in aviation one of the most important factors is mass. Recently with the innovations in 3D printing technologies, the importance of this phenomenon has increased. Numerical simulation of multi-particle systems is based on considering binary interactions; therefore, a simplified but as much accurate as possible particle interaction model is required for simulations. Particular cases of axisymmetric particle to substrate contact is modelled at select impact velocities and using different layer thicknesses. When modelling the particle impact at high contact velocity, a substrate thickness dependent change in the restitution coefficient was observed. This change happens is due to elastic waves and is important both to coating and 3D printing technologies when building layers of different properties materials.

Long-ranged order in a thermally driven system with temperature dependent interactions

Aggregation of macro-molecules under external drive is far from understood. An important driving situation is achieved by temperature difference. The inter-particle interaction in metallic nanoparticles with ligand capping is reported...

An experiment design for schools to demonstrate the Maxwell distribution

The article describes a new version of a demonstration experiment for the Maxwell distribution. In the first part students analyse the applicability of the Gaussian distribution to the projection of the particle velocities in the suggested experiment. Further, students observe two-dimensional distribution of particles by the modulus of velocity in a mechanical demonstration model and compare the results with theoretical provisions. Demonstration of the two-dimensional version of the Maxwell distribution for particle interaction allows students to independently derive formulas for the three-dimensional Maxwell distribution for particles in an ideal gas. The use of the suggested demonstration ensures active engagement in fundamentally important physical content.