Design, Fabrication and Characterization of MEMS Micro-resistojet Thrusters

Small satellites require efficient propulsion systems for attitude and orbit control. This thesis focuses on the development and characterization of two distinct types of micro-resistojet thrusters, namely Vaporizing Liquid Micro-resistojet (VLM) and Low Pressure Micro-resistojet (LPM). Both concepts are developed at TU Delft and are designed to...

Design and Testing of a Controllable Hinge for a Flapping-wing Micro Air Vehicle

Flying drones have been a well-established field of engineering for many years now. With the wave of bio-inspired design came the idea of flapping wing micro air vehicles (FWMAVs). These drones use flapping wings instead of fixed or rotary wings to generate their lift, giving them the potential for agile movement and application in confined...

Galvanic Brain-Coupled Communication Among Freely Floating Micro-Scale Implants

This paper presents a new communication method between micro-scale freely floating brain implants based on galvanic coupling (GC), called "Brain-Coupled Communication" (BCC). Since the transmission efficiency based on GC is highly dependent on the system’s geometry and the electromagnetic properties of the tissue, finite element models in COMSOL...

Micro-scale effects of stylolite orientation on the motion of tensile failure: A study analyzing strain fields of stylolite limestones using Particle Image Velocimetry

Many laboratory tests of samples where the rock fractures are based on<br/>meso-scale (cm) characterization of effective ‘intact’ strength parameters neglecting the microstructure effects. Understanding fracturing processes at<br/>micro-scale (mm) will require models with microstructure data. However,<br/>data is lacking on micro-scale.<br/...

Trench Siltation near the ETM of a Well-mixed Estuary

To exploit its socio-economic functions, engineering measures are regularly applied in estuaries. Estuaries are, however, known to be very complex systems. Stemming from this complexity is the generation of a so-called estuarine turbidity maximum (ETM), which poses great siltation problems to the engineering measures. An engineering measure,...

Discrete lattice fracture modelling of hydrated cement paste under uniaxial compression at micro-scale

A combination of laboratory experiments and numerical simulations at multiple length scales can provide in-depth understanding of fracture behaviour of hydrated cement paste (HCP). To that end, the current work presents a numerical study on compressive failure of hydrated cement paste (HCP) at the micro-scale. Virtual specimens consisting of...

Micro-scale computational analysis of Fused Filament Fabricated Materials: Experimentally-validated Finite Element Analyses of Representative Volume Elements

This work aims at predicting the elasto-plastic and fracture behavior of ABS polymers obtained by Fused Filament Fabrication (FFF). The strategy adopted is to characterize the microstructure of Representative Volume Elements (RVEs) of the material, as well as the mechanical properties of the polymeric filament used in the FFF process and then...

Micro-Cantilever Testing Of Cementitious Materials Under Various Loading Conditions

Nanoindentation is usually used to investigate local elastic properties and hardness of materials. In this paper, the nanoindenter served as a loading tool to perform micro scale bending tests and measure the global response of micro-scale specimens. For testing, cement paste cantilever beams with a square cross-section of 300 μm × 300 μm were...

Bricks as Spatial Sound Modulators: Towards tuning the geometry

The current research is part of a trans-disciplinary discussion on the long-lasting impact of the acoustic environment on cognitive performance, literacy and auditory perception for preschool children, aiming to underlie the increasing necessity to perfectly tune every-day facilities such as schools and work spaces, rather...

Micro-scale cavities in the slip- and transition-flow regimes

highlight the fact that many micro-flows that have been considered are simple planar flows and typical classification systems are defined on such flows. We show that for complex flows, such as the driven cavity, non-equilibrium effects are more appreciable and their onset occurs at lower Knudsen numbers than expected.

A Continuum/Kinetic Hybrid Approach for Multi-Scale Flow Simulation

This paper describes a continuum/kinetic hybrid approach for simulating the continuum to free molecule, multi-scale flows. Domain decomposition strategy is adopted for coupling the continuum and kinetic approaches. A multi-scale computational domain is decomposed into the continuum regions and the kinetic regions. Instead of the direct...