Development and analysis of microstructures for the transplantation of thermally sprayed coatings

Thermally sprayed coatings and tribological surfaces are a point of interest in many industrial sectors. They are used for better wear resistance of lightweight materials or for oil retention on surfaces. Lightweight materials are often used in the automotive industry as a weight-saving solution in the production of engine blocks. For this, it is necessary to coat the cylinder liners to ensure wear resistance. In most cases, the coating is sprayed directly onto the surface. Previous research has shown that it is possible to transfer these coatings inversely onto other surfaces. This was achieved with plasma sprayed coatings which were transplanted onto pressure-casted surfaces. These transplanted surfaces exhibited better adhesive strength, smoother surfaces, and lower form deviation compared to directly coated surfaces. Additionally, it was shown that even microstructures of a surface coated by plasma spraying can be transferred to pressure-casted surfaces. This paper presents the development and micromilling of different microstructures for transferring thermally sprayed coatings onto pressure-casted surfaces. In the development process, microstructures with different shapes and aspect ratios as well as thin tribological surfaces are designed in order to evaluate the advantages and limitations of the transplantation process. In subsequent experiments, the micromilling process and a simulation of the coating transplantation are presented and analyzed.DFG/Mo 881/9-1DFG/Bi 498/6-

Particle Based Alloying by Accumulative Roll Bonding in the System Al-Cu

The formation of alloys by particle reinforcement during accumulative roll bonding (ARB), and subsequent annealing, is introduced on the basis of the binary alloy system Al-Cu, where strength and electrical conductivity are examined in different microstructural states. An ultimate tensile strength (UTS) of 430 MPa for Al with 1.4 vol.% Cu was reached after three ARB cycles, which almost equals UTS of the commercially available Al-Cu alloy AA2017A with a similar copper content. Regarding electrical conductivity, the UFG structure had no significant influence. Alloying of aluminum with copper leads to a linear decrease in conductivity of 0.78 µΩ∙cm/at.% following the Nordheim rule. On the copper-rich side, alloying with aluminum leads to a slight strengthening, but drastically reduces conductivity. A linear decrease of electrical conductivity of 1.19 µΩ∙cm/at.% was obtained

Towards automated joining element design

Product variety and its induced manufacturing complexity remains to increase and therefore greatens challenges for design of joining elements. Historically, joining element design was a paper-based process with incomplete variety documentation and is digitalized only by replacing paper for 3D space. Currently, joining element design remains an ambiguous manual task with limited automation, resulting in long iterative, error prone development trajectories and costly reworks. Thus, processes in practice conflict with required capabilities. Artificial intelligence helps to solve such conflicts by taking over repetitive tasks, preventing human errors, optimizing designs and enabling designers to focus on their core competencies. This paper proposes a novel artificial intelligence method toolbox as a foundation to automate joining element design in manufacturing industries. The methodology aims to incorporate multiple lifecycle requirements including large product variety

Abschlussberichte Q-Tutorien HU Berlin, Wintersemester 2017/18 und Sommersemester 2018

Das bologna.lab der Humboldt-Universität zu Berlin fördert im Rahmen des Qualitätspakts Lehre (BMBF, 2012-2020) eine Reihe von Projekten mit dem Ziel, bereits ab dem Bachelorstudium Freiräume für forschendes Lernen zu schaffen und diese mit forschungsnahen Lehrangeboten zu füllen. Eines dieser Projekte sind die Q-Tutorien, deren Abschlussberichte in diesem Band versammelt sind. In diesen studentischen Veranstaltungen bearbeitet eine Gruppe Studierender ein selbst gewähltes Forschungsthema in eigenständiger, interdisziplinärer und möglichst innovativer Projektarbeit

Simple plant-based production and purification of the assembled human ferritin heavy chain as a nanocarrier for tumor-targeted drug delivery and bioimaging in cancer therapy

Nanoparticles are used as carriers for the delivery of drugs and imaging agents. Proteins are safer than synthetic nanocarriers due to their greater biocompatibility and the absence of toxic degradation products. In this context, ferritin has the additional benefit of inherently targeting the membrane receptor transferrin 1, which is overexpressed by most cancer cells. Furthermore, this self-assembling multimeric protein can be loaded with more than 2000 iron atoms, as well as drugs, contrast agents, and other cargos. However, recombinant ferritin currently costs ~3.5 million € g-1 , presumably because the limited number of producers cannot meet demand, making it generally unaffordable as a nanocarrier. Because plants can produce proteins at very-large-scale, we developed a simple, proof-of-concept process for the production of the human ferritin heavy chain by transient expression in Nicotiana benthamiana. We optimized the protein yields by screening different compartments and 5'-untranslated regions in PCPs, and selected the best-performing construct for production in differentiated plants. We then established a rapid and scalable purification protocol by combining pH and heat treatment before extraction, followed by an ultrafiltration/diafiltration size-based separation process. The optimized process achieved ferritin levels of ~40 mg kg-1 fresh biomass although depth filtration limited product recovery to ~7%. The purity of the recombinant product was >90% at costs ~3% of the current sales price. Our method therefore allows the production of affordable ferritin heavy chain as a carrier for therapeutic and diagnostic agents, which is suitable for further stability and functionality testing in vitro and in vivo