Header logo is


2019


The acoustic hologram and particle manipulation with structured acoustic fields
The acoustic hologram and particle manipulation with structured acoustic fields

Melde, K.

Karlsruher Institut für Technologie (KIT), May 2019 (phdthesis)

Abstract
This thesis presents holograms as a novel approach to create arbitrary ultrasound fields. It is shown how any wavefront can simply be encoded in the thickness profile of a phase plate. Contemporary 3D-printers enable fabrication of structured surfaces with feature sizes corresponding to wavelengths of ultrasound up to 7.5 MHz in water—covering the majority of medical and industrial applications. The whole workflow for designing and creating acoustic holograms has been developed and is presented in this thesis. To reconstruct the encoded fields a single transducer element is sufficient. Arbitrary fields are demonstrated in transmission and reflection configurations in water and air and validated by extensive hydrophone scans. To complement these time-consuming measurements a new approach, based on thermography, is presented, which enables volumetric sound field scans in just a few seconds. Several original experiments demonstrate the advantages of using acoustic holograms for particle manipulation. Most notably, directed parallel assembly of microparticles in the shape of a projected acoustic image has been shown and extended to a fabrication method by fusing the particles in a polymerization reaction. Further, seemingly dynamic propulsion from a static hologram is demonstrated by controlling the phase gradient along a projected track. The necessary complexity to create ultrasound fields with set amplitude and phase distributions is easily managed using acoustic holograms. The acoustic hologram is a simple and cost-effective tool for shaping ultrasound fields with high-fidelity. It is expected to have an impact in many applications where ultrasound is employed.

pf

link (url) DOI [BibTex]

2019



no image
Ferromagnetic colloids in liquid crystal solvents

Zarubin, G.

Universität Stuttgart, Stuttgart, 2019 (phdthesis)

icm

link (url) DOI [BibTex]

link (url) DOI [BibTex]


no image
Fluctuating interface with a pinning potential

Pranjić, Daniel

Universität Stuttgart, Stuttgart, 2019 (mastersthesis)

icm

[BibTex]

[BibTex]


no image
Controlling pattern formation in the confined Schnakenberg model

Beyer, David Bernhard

Universität Stuttgart, Stuttgart, 2019 (mastersthesis)

icm

[BibTex]

[BibTex]


Dynamics of self-propelled colloids and their application as active matter
Dynamics of self-propelled colloids and their application as active matter

Choudhury, U.

University of Groningen, Zernike Institute for Advanced Materials, 2019 (phdthesis)

Abstract
In this thesis, the behavior of active particles spanning from single particle dynamics to collective behavior of many particles is explored. Active colloids are out-of equilibrium systems that have been studied extensively over the past 15 years. This thesis addresses several phenomena that arise in the field of active colloids.

pf

link (url) [BibTex]

link (url) [BibTex]


no image
Interfaces in fluids of ionic liquid crystals

Bartsch, H.

Universität Stuttgart, Stuttgart, 2019 (phdthesis)

icm

link (url) DOI [BibTex]

link (url) DOI [BibTex]

2018


Nanoscale robotic agents in biological fluids and tissues
Nanoscale robotic agents in biological fluids and tissues

Palagi, S., Walker, D. Q. T., Fischer, P.

In The Encyclopedia of Medical Robotics, 2, pages: 19-42, 2, (Editors: Desai, J. P. and Ferreira, A.), World Scientific, October 2018 (inbook)

Abstract
Nanorobots are untethered structures of sub-micron size that can be controlled in a non-trivial way. Such nanoscale robotic agents are envisioned to revolutionize medicine by enabling minimally invasive diagnostic and therapeutic procedures. To be useful, nanorobots must be operated in complex biological fluids and tissues, which are often difficult to penetrate. In this chapter, we first discuss potential medical applications of motile nanorobots. We briefly present the challenges related to swimming at such small scales and we survey the rheological properties of some biological fluids and tissues. We then review recent experimental results in the development of nanorobots and in particular their design, fabrication, actuation, and propulsion in complex biological fluids and tissues. Recent work shows that their nanoscale dimension is a clear asset for operation in biological tissues, since many biological tissues consist of networks of macromolecules that prevent the passage of larger micron-scale structures, but contain dynamic pores through which nanorobots can move.

pf

link (url) DOI [BibTex]

2018


link (url) DOI [BibTex]


Colloidal Chemical Nanomotors
Colloidal Chemical Nanomotors

Alarcon-Correa, M.

Colloidal Chemical Nanomotors, pages: 150, Cuvillier Verlag, MPI-IS , June 2018 (phdthesis)

Abstract
Synthetic sophisticated nanostructures represent a fundamental building block for the development of nanotechnology. The fabrication of nanoparticles complex in structure and material composition is key to build nanomachines that can operate as man-made nanoscale motors, which autonomously convert external energy into motion. To achieve this, asymmetric nanoparticles were fabricated combining a physical vapor deposition technique known as NanoGLAD and wet chemical synthesis. This thesis primarily concerns three complex colloidal systems that have been developed: i)Hollow nanocup inclusion complexes that have a single Au nanoparticle in their pocket. The Au particle can be released with an external trigger. ii)The smallest self-propelling nanocolloids that have been made to date, which give rise to a local concentration gradient that causes enhanced diffusion of the particles. iii)Enzyme-powered pumps that have been assembled using bacteriophages as biological nanoscaffolds. This construct also can be used for enzyme recovery after heterogeneous catalysis.

pf

[BibTex]

[BibTex]


no image
Pattern forming systems under confinement

Maihöfer, Michael

Universität Stuttgart, Stuttgart, 2018 (mastersthesis)

icm

[BibTex]

[BibTex]


no image
Effective interactions between colloidal particles in critical solvents

Labbe-Laurent, M.

Universität Stuttgart, Stuttgart, 2018 (phdthesis)

icm

link (url) DOI [BibTex]

link (url) DOI [BibTex]


no image
Non-equilibrium dynamics of a binary solvent around heated colloidal particles

Wilke, Moritz

Universität Stuttgart, Stuttgart, 2018 (mastersthesis)

icm

[BibTex]

[BibTex]


no image
Monte Carlo study of colloidal structure formation at fluid interfaces

Meiler, Tim

Universität Stuttgart, Stuttgart, 2018 (mastersthesis)

icm

[BibTex]

[BibTex]


no image
Electrolyte solutions and simple fluids at curved walls

Reindl, A.

Universität Stuttgart, Stuttgart, 2018 (phdthesis)

icm

link (url) DOI [BibTex]

link (url) DOI [BibTex]


no image
Surface structure of liquid crystals

Sattler, Alexander

Universität Stuttgart, Stuttgart, 2018 (mastersthesis)

icm

[BibTex]

[BibTex]


no image
Dynamics of an active particle in confined viscous flows

Pöhnl, Ruben

Universität Stuttgart, Stuttgart, 2018 (mastersthesis)

icm

[BibTex]

[BibTex]


no image
Electrostatic interaction between colloids with constant surface potentials at fluid interfaces

Bebon, Rick

Universität Stuttgart, Stuttgart, 2018 (mastersthesis)

icm

[BibTex]

[BibTex]

2008


no image
Dynamic density functional theory (DDFT)

Rauscher, M.

In Encyclopedia of Microfluidics and Nanofluidics, pages: 428-433, Springer, New York, 2008 (incollection)

icm

[BibTex]

2008


[BibTex]


no image
Entropic Forces on Bio-Molecules

Hansen-Goos, H.

Universität Stuttgart, Stuttgart, 2008 (phdthesis)

icm

link (url) [BibTex]

link (url) [BibTex]


no image
Wetting of geometrically structured substrates

Marinescu, M.

Universität Stuttgart, Stuttgart, Germany, 2008 (mastersthesis)

icm

[BibTex]

[BibTex]


no image
Fluktuations- und Kapillarkräfte zwischen Kolloiden an fluiden Grenzflächen

Lehle, H.

Universität Stuttgart, Stuttgart, 2008 (phdthesis)

icm

link (url) [BibTex]

link (url) [BibTex]


no image
Microscopic calculation of line tensions

Merath, R.-J.

Universität Stuttgart, Stuttgart, 2008 (phdthesis)

icm

link (url) [BibTex]

link (url) [BibTex]


no image
Lattice model for fluid flow in narrow channels

Dotti, C.

Universität Stuttgart, Stuttgart, 2008 (phdthesis)

icm

[BibTex]

[BibTex]


no image
Critical Casimir forces

Mohry, T. F.

Universität Stuttgart, Stuttgart, 2008 (mastersthesis)

icm

[BibTex]

[BibTex]


no image
Adaptive stair-climbing behaviour with a hybrid legged-wheeled robot

Eich, M., Grimminger, F., Kirchner, F.

In Advances In Mobile Robotics, pages: 768-775, World Scientific, August 2008 (incollection)

am

DOI [BibTex]

DOI [BibTex]

2003


no image
Coexisting Phases in Binary Platelet Mixtures

Bier, M.

Universität Stuttgart, Stuttgart, 2003 (mastersthesis)

icm

[BibTex]

2003


[BibTex]


no image
Capillary forces between structured substrates

De Souza, E. J.

Universität Stuttgart, Stuttgart, 2003 (mastersthesis)

icm

[BibTex]

[BibTex]


no image
Statistical physics of stochastic geometries

Brodatzki, U.

Universität Wuppertal, Wuppertal, 2003 (phdthesis)

icm

[BibTex]

[BibTex]


no image
Colloidal Particles in Critical Fluids

Schlesener, F.

Universität Stuttgart, Stuttgart, 2003 (phdthesis)

icm

[BibTex]

[BibTex]


no image
Diffusion in quasicrystals

Mehrer, H., Galler, R., Frank, W., Blüher, R., Strohm, A.

In Quasicrystals - Structure and Physical Properties, pages: 312-337, Wiley-VCH, Weinheim, 2003 (incollection)

icm

[BibTex]

[BibTex]


no image
Structure and Solvation Forces in Binary Hard-Sphere Mixtures

Grodon, C.

Universität Stuttgart, Stuttgart, 2003 (mastersthesis)

icm

[BibTex]

[BibTex]

1999


no image
Nonparametric regression for learning nonlinear transformations

Schaal, S.

In Prerational Intelligence in Strategies, High-Level Processes and Collective Behavior, 2, pages: 595-621, (Editors: Ritter, H.;Cruse, H.;Dean, J.), Kluwer Academic Publishers, 1999, clmc (inbook)

Abstract
Information processing in animals and artificial movement systems consists of a series of transformations that map sensory signals to intermediate representations, and finally to motor commands. Given the physical and neuroanatomical differences between individuals and the need for plasticity during development, it is highly likely that such transformations are learned rather than pre-programmed by evolution. Such self-organizing processes, capable of discovering nonlinear dependencies between different groups of signals, are one essential part of prerational intelligence. While neural network algorithms seem to be the natural choice when searching for solutions for learning transformations, this paper will take a more careful look at which types of neural networks are actually suited for the requirements of an autonomous learning system. The approach that we will pursue is guided by recent developments in learning theory that have linked neural network learning to well established statistical theories. In particular, this new statistical understanding has given rise to the development of neural network systems that are directly based on statistical methods. One family of such methods stems from nonparametric regression. This paper will compare nonparametric learning with the more widely used parametric counterparts in a non technical fashion, and investigate how these two families differ in their properties and their applicabilities. We will argue that nonparametric neural networks offer a set of characteristics that make them a very promising candidate for on-line learning in autonomous system.

am

link (url) [BibTex]

1999


link (url) [BibTex]