Rapid Growth of Dense and Long Carbon Nanotube Arrays and Its Application in Spinning Thread

Carbon nanotubes (CNTs), a dependable allotrope of carbon, are foreseen to lead technology further to its reach. Also, the most researched carbon allotrope in its form. Drawable CNTs have recently unraveled numerous possible applications utilizing vertically aligned CNTs also termed as “CNT forest.” In recent years, the rapid growth of dense and long carbon nanotube arrays has succeeded in surpassing its challenges by synthesizing dense and long CNT arrays. Length, density, and drawability tuning in the synthesis of CNT arrays have always been a complex issue lately. However, numerous research techniques emerged focusing on length and density control. Hence, this book chapter aids in unveiling the current achievements in the growth of dense and long CNT arrays and their application in spinning threads or CNT yarns with numerous other possible applications

Using FPGA Block-RAM for fast white light interferometry

White light interferometry is a time consuming operation even on modern architectures. To overcome the high power consumption and size of traditional desktop computers an embedded approach containing the hybrid architecture Zynq will be presented. This architecture contains a dual core ARM and programmable logic provided by an FPGA. FPGAs offer massively parallel logic gates and DSP-slices to parallelise certain tasks. Another important part is the internal memory BRAM. The presented approach aims to speedup calculation time of the ARM processor by utilization of this BRAM. It is well known that memory transfers consume a lot of time. To speed the transfers up, the bottlenecks have to be identified. In this paper it will be illustrated how to easily access an FPGA BRAM from a running operating system and the possible speedup will be analysed and estimated

PtyNAMi: ptychographic nano-analytical microscope

Ptychographic X-ray imaging at the highest spatial resolution requires an optimal experimental environment, providing a high coherent flux, excellent mechanical stability and a low background in the measured data. This requires, for example, a stable performance of all optical components along the entire beam path, high temperature stability, a robust sample and optics tracking system, and a scatter-free environment. This contribution summarizes the efforts along these lines to transform the nanoprobe station on beamline P06 (PETRA III) into the ptychographic nano-analytical microscope (PtyNAMi

Filled Carbon Nanotubes as Anode Materials for Lithium-Ion Batteries

Downsizing well-established materials to the nanoscale is a key route to novel functionalities, in particular if different functionalities are merged in hybrid nanomaterials. Hybrid carbon-based hierarchical nanostructures are particularly promising for electrochemical energy storage since they combine benefits of nanosize effects, enhanced electrical conductivity and integrity of bulk materials. We show that endohedral multiwalled carbon nanotubes (CNT) encapsulating high-capacity (here: conversion and alloying) electrode materials have a high potential for use in anode materials for lithium-ion batteries (LIB). There are two essential characteristics of filled CNT relevant for application in electrochemical energy storage: (1) rigid hollow cavities of the CNT provide upper limits for nanoparticles in their inner cavities which are both separated from the fillings of other CNT and protected against degradation. In particular, the CNT shells resist strong volume changes of encapsulates in response to electrochemical cycling, which in conventional conversion and alloying materials hinders application in energy storage devices. (2) Carbon mantles ensure electrical contact to the active material as they are unaffected by potential cracks of the encapsulate and form a stable conductive network in the electrode compound. Our studies confirm that encapsulates are electrochemically active and can achieve full theoretical reversible capacity. The results imply that encapsulating nanostructures inside CNT can provide a route to new high-performance nanocomposite anode materials for LIB.Comment: Invite

Dynamik als Leitprinzip zur Revitalisierung des Leipziger Auensystems

10 Thesen zur Revitalisierung der Leipziger Aue, eine Vision, ein konkreter Maßnahmenkatalog mit Karte zu Dynamisierungsoptionen und ein Ausblick mit Realisierungsvorschläge

Nanofocusing with aberration-corrected rotationally parabolic refractive X-ray lenses

Wavefront errors of rotationally parabolic refractive X-ray lenses made of beryllium (Be CRLs) have been recovered for various lens sets and X-ray beam configurations. Due to manufacturing via an embossing process, aberrations of individual lenses within the investigated ensemble are very similar. By deriving a mean single-lens deformation for the ensemble, aberrations of any arbitrary lens stack can be predicted from the ensemble with \bar{\sigma} = 0.034λ. Using these findings the expected focusing performance of current Be CRLs are modeled for relevant X-ray energies and bandwidths and it is shown that a correction of aberrations can be realised without prior lens characterization but simply based on the derived lens deformation. The performance of aberration-corrected Be CRLs is discussed and the applicability of aberration-correction demonstrated over wide X-ray energy ranges

The tidal effects in the Finite-volumE Sea ice–Ocean Model (FESOM2.1): a comparison between parameterised tidal mixing and explicit tidal forcing

Tides are proved to have a significant effect on the ocean and climate. Previous modelling research either adds a tidal mixing parameterisation or an explicit tidal forcing to the ocean models. However, no research compares the two approaches in the same framework. Here we implement both schemes in a general ocean circulation model and assess both methods by comparing the results. The aspects for comparison involve hydrography, sea ice, meridional overturning circulation (MOC), vertical diffusivity, barotropic streamfunction and energy diagnostics. We conclude that although the mesh resolution is poor in resolving internal tides in most mid-latitude and shelf-break areas, explicit tidal forcing still shows stronger tidal mixing at the Kuril–Aleutian Ridge and the Indonesian Archipelago than the tidal mixing parameterisation. Beyond that, the explicit tidal forcing method leads to a stronger upper cell of the Atlantic MOC by enhancing the Pacific MOC and the Indonesian Throughflow. Meanwhile, the tidal mixing parameterisation leads to a stronger lower cell of the Atlantic MOC due to the tidal mixing in deep oceans. Both methods maintain the Antarctic Circumpolar Current at a higher level than the control run by increasing the meridional density gradient. We also show several phenomena that are not considered in the tidal mixing parameterisation, for example, the changing of energy budgets in the ocean system, the bottom drag induced mixing on the continental shelves and the sea ice transport by tidal motions. Due to the limit of computational capacity, an internal-tide-resolving simulation is not feasible for climate studies. However, a high-resolution short-term tidal simulation is still required to improve parameters and parameterisation schemes in climate studies