Excimerlaserstrahlbiegen dünner metallischer Folien mit homogener Lichtlinie

Thanks to laser technology, forming using thermally induced tensions has found Entrance into micro technology, initially starting from flame straightening in shipbuilding. To realize bendings the Temperature-Gradient-Mechanism can be used. Therefore the compressive stresses induced need to be limited to·surface-near areas of the work piece. Thus, the excimer laser allows the bending of thin metallic foils without the use of any exterior forces. The work illustrates excimer laser beam bending using a homogeneous light line, discusses various analytic models·and describes appearing phenomena, when irradiating at fluences above ablation threshold, within a newly developed descriptive model.Das Umformen mittels thermisch induzierter Spannungen hat, ausgehend vom Flammrichten im Schiffsbau, durch den Einsatz der Lasertechnologie auch Einzug in die Mikrotechnik gehalten. Um·Biegungen zu realisieren, macht man vom Temperaturgradienten-Mechanismus (T M) Gebrauch. Die dabei mittels Laser zunächst induzierten thermischen Druckspannungen lassen sich so auf' oberflächennahe Bauteilbereiche begrenzen und können hier eine plastische Deformation unter Druck bewirken. Als Folge der Kontraktion während des Abkühlens·entstehen an der bestrahlten Oberfläche Zugeigenspannungen, die zu·einer bleibenden Gestaltänderung führen. Der Excimerlaser ist eine geeignete Strahlquelle für das berührungslose Biegen dünner metallischer Folien. Die Arbeit beleuchtet umfassend das Excimerlaserstrahlbiegen mit homogener Lichtlinie, diskutiert verschiedene analytische Prozessmodelle und beschreibt auftretende Phänomene beim Biegen mittels Energiedichten oberhalb der Abtragsschwelle in einem neu entwickelten qualitativen Modell

Critical Review of Processing and Classification Techniques for Images and Spectra in Microplastic Research

Microplastic research is a rapidly developing field, with urgent needs for high throughput and automated analysis techniques. We conducted a review covering image analysis from optical microscopy, scanning electron microscopy, fluorescence microscopy, and spectral analysis from Fourier transform infrared (FT-IR) spectroscopy, Raman spectroscopy, pyrolysis gas–chromatography mass–spectrometry, and energy dispersive X-ray spectroscopy. These techniques were commonly used to collect, process, and interpret data from microplastic samples. This review outlined and critiques current approaches for analysis steps in image processing (color, thresholding, particle quantification), spectral processing (background and baseline subtraction, smoothing and noise reduction, data transformation), image classification (reference libraries, morphology, color, and fluorescence intensity), and spectral classification (reference libraries, matching procedures, and best practices for developing in-house reference tools). We highlighted opportunities to advance microplastic data analysis and interpretation by (i) quantifying colors, shapes, sizes, and surface topologies with image analysis software, (ii) identifying threshold values of particle characteristics in images that distinguish plastic particles from other particles, (iii) advancing spectral processing and classification routines, (iv) creating and sharing robust spectral libraries, (v) conducting double blind and negative controls, (vi) sharing raw data and analysis code, and (vii) leveraging readily available data to develop machine learning classification models. We identified analytical needs that we could fill and developed supplementary information for a reference library of plastic images and spectra, a tutorial for basic image analysis, and a code to download images from peer reviewed literature. Our major findings were that research on microplastics was progressing toward the use of multiple analytical methods and increasingly incorporating chemical classification. We suggest that new and repurposed methods need to be developed for high throughput screening using a diversity of approaches and highlight machine learning as one potential avenue toward this capability

Critical Assessment of Analytical Methods for the Harmonized and Cost-Efficient Analysis of Microplastics

Microplastics are of major concerns for society and is currently in the focus of legislators and administrations. A small number of measures to reduce or remove primary sources of microplastics to the environment are currently coming into effect. At the moment, they have not yet tackled important topics such as food safety. However, recent developments such as the 2018 bill in California are requesting the analysis of microplastics in drinking water by standardized operational protocols. Administrations and analytical labs are facing an emerging field of methods for sampling, extraction, and analysis of microplastics, which complicate the establishment of standardized operational protocols. In this review, the state of the currently applied identification and quantification tools for microplastics are evaluated providing a harmonized guideline for future standardized operational protocols to cover these types of bills. The main focus is on the naked eye detection, general optical microscopy, the application of dye staining, flow cytometry, Fourier transform infrared spectroscopy (FT-Ir) and microscopy, Raman spectroscopy and microscopy, thermal degradation by pyrolysis–gas chromatography–mass spectrometry (py-GC-MS) as well as thermo-extraction and desorption gas chromatography–mass spectrometry (TED-GC-MS). Additional techniques are highlighted as well as the combined application of the analytical techniques suggested. An outlook is given on the emerging aspect of nanoplastic analysis. In all cases, the methods were screened for limitations, field work abilities and, if possible, estimated costs and summarized into a recommendation for a workflow covering the demands of society, legislation, and administration in cost efficient but still detailed manner

Combined Gas and Steam Cycle for a Gas-Cooled Solar Tower Power Plant

In gas-cooled solar power plants the radiant energy of the sun is transferred to the cycle fluid in a cavity type solar receiver and converted into electric energy by means of a combined gas and steam turbine cycle incorporating a waste heat steam generator. The design and optimization of the energy conversion system in accordance with solar-specific considerations are described with particular regard to the gas turbine. In designing the energy conversion system several variants on the combined cycle with waste heat steam generator are investigated and special measures for the improvement of the cycle efficiency, such as the refinement of the steam process through the addition of pressure stages are introduced. It is demonstrated that the solar power plant meets the requirements both for straight solar and constant load operation with fossil fuel substitution. In order to establish the possibilities of attaining high part-load efficiencies in straight solar operation, two modes, variable and constant speed of the gas turbine, are compared with one another.</jats:p

Specific immuno-modulation and therapy by means of high pressure treated allergens.

A high-pressure treatment (&gt; 100 MPa) can change the quarternary, tertiary, and secondary structures of proteins. Experiments have shown the prospects of high-pressure treatment for the development of viral and tumour vaccines, for the inactivation of resected infection- and tumour-bearing bone segments and for the decrease of food allergenicity. Allergic patients had minor or no allergy symptoms against high pressure treated foods, which were birch pollen allergy related (hazelnut, carrot, cherry, peach, celery, and apple). Three patients with a heavy allergy against apple could be hyposensitized by means of a specific immuno-therapy with high pressure treated apple

Combined Gas and Steam Cycle for a Gas-Cooled Solar Tower Power Plant

In gas-cooled solar power plants the radiant energy of the sun is transferred to the cycle fluid in a cavity type solar receiver and converted into electric energy by means of a combined gas and steam turbine cycle incorporating a waste heat steam generator. The design and optimization of the energy conversion system in accordance with solar-specific considerations are described with particular regard to the gas turbine. In designing the energy conversion system several variants on the combined cycle with waste heat steam generator are investigated and special measures for the improvement of the cycle efficiency, such as the refinement of the steam process through the addition of pressure stages are introduced. It is demonstrated that the solar power plant meets the requirements both for straight solar and constant load operation with fossil fuel substitution. In order to establish the possibilities of attaining high part-load efficiencies in straight solar operation, two modes, variable and constant speed of the gas turbine, are compared with one another.</jats:p