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1,091 results on '"Gerlach, Gerald"'

52. Erratum to: Potentials and challenges of deep-learning-assisted porosity prediction based on thermographic in-situ monitoring in laser powder bed fusion.

Author

Oster, Simon, Scheuschner, Nils, Chand, Keerthana, Altenburg, Simon J., and Gerlach, Gerald

Subjects
POROSITY, COMPUTED tomography
Abstract

This erratum corrects an error in a previously published study on deep-learning-assisted porosity prediction in laser powder bed fusion. The error was related to the registration of datasets, which led to misalignment of cluster positions. The authors re-performed sample pre-processing and model optimization, resulting in an increased prediction performance. The dataset size increased, and the model architecture was adjusted. The updated model showed slightly lower scores but improved mapping between thermogram feature data and porosity data. The corrections and changes do not substantially affect the conclusions of the study. [Extracted from the article]

Published
2024
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56. Biochemical piezoresistive sensors based on pH- and glucose-sensitive hydrogels for medical applications

Author

Schmidt Ulrike, Guenther Margarita, and Gerlach Gerald

Subjects
biochemical sensor, glucose-sensitive, hydrogel, medical applications, ph-sensitive, piezoresistive, Medicine
Abstract

Many conventional analysis techniques to detect chemical or biological species are able to achieve a high detection sensitivity, however, they are equipment- or time-expensive due to a multi-step procedure. In this work we describe sensor concepts using piezoresistive pressure sensor chips with integrated analyte-sensitive hydrogels, that enable inexpensive and robust biochemical sensors which are miniaturizable and in-line capable. Biocompatible hydrogels were developed and tested for pH- and glucose-monitoring during the chemical and biochemical processes. For that, monomer mixtures based on hydroxypropyl methacrylate HPMA, 2-(dimethylamino)ethyl methacrylate DMAEMA, tetraethylene glycol dimethacrylate TEGDMA and ethylene glycol EG were photo-polymerized. By means of carbodiimide chemistry, glucose oxidase was bound to the pH-sensitive HPMA/DMAEMA/TEGDMA/EG hydrogel squares causing the glucose-sensitivity. The crosslinked hydrogels were integrated in piezoresistive pressure sensors of different designs. pH- and glucose-depending reversible gel swelling processes were observed by means of the output voltage of dip sensors and of a novel implantable flexible sensor set-up. Due to its biocompatible components, the latter could be used inside the human body monitoring physiological blood values, for example glucose.

Published
2016
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64. The size-of-source effect in thermography

Author

Budzier, Helmut and Gerlach, Gerald

Subjects
Technology
Abstract

In thermometry, the displayed temperature value of an object depends on the size of the object. This behaviour, also known as the size-of-source effect (SSE), might be a major cause of measurement uncertainty in a thermoscene. The SSE is caused by diffraction, scattering, reflection, aberration and digitization in the optoelectronic propagation path. The influence of diffraction and digitization (sampling and pixelization) can be described advantageously with the modulation transfer function MTF. The system MTF of an uncooled camera is determined by the diffraction in the lens (optical MTF) and the averaging of the radiation over the pixel area (pixel MTF). If the system MTF is known, the contrast reduction and, thus, the SSE can be calculated. Especially with very small objects, e.g. hotspots creating an image covering less than 4 pixel × 4 pixel on the focal plane, the displayed temperatures are much too low. When imaging large objects, such as area blackbodies, not only the edge areas are affected, but also the entire image. Finally, the contrast reduction by the MTF is explained by means of a complex scene (Siemens star).

Published
2021

71. Impedimetrischer Inline-Biofilmsensor

Author

Delan, Annekatrin, primary, Becker, Michael, additional, Boer, Michael, additional, Liefeith, Klaus, additional, Frant, Marion, additional, Rost, Jürgen, additional, Schirmer, Uwe, additional, Pietsch, Christian, additional, Glöß, Daniel, additional, Günther, Margarita, additional, and Gerlach, Gerald, additional

Published
2022
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91. Morphological characterization and porosity profiles of tantalum glancing-angle-deposited thin films

Author

Ott, Tobias and Gerlach, Gerald

Subjects
lcsh:T, lcsh:Technology
Abstract

Glancing angle deposition (GLAD) is a physical vapor deposition (PVD) process using a substrate that rotates tilted at an angle to the evaporation source. Depending on the deposition conditions, it provides the controlled formation of regular nanostructures during the PVD process. As a result, a wide variety of shapes, such as spirals or vertical columns, can be easily fabricated in the nanometer range. For this reason, GLAD has already been proven reliable in the production of optical coatings with very low reflectance in a broad spectral range. This paper examines the morphology of tantalum nanostructures deposited on planar silicon substrates by electron beam evaporation. The prepared samples are characterized by scanning electron microscope (SEM) images at a breaking edge with respect to the layer structure and by focused ion beam (FIB) SEM images of the cross-sectional areas with respect to the porosity. The porosity can be used to model the optical properties of the thin film with the effective medium theory (EMT). Our work studies the relationship between the evaporation parameters (growth pitch and deposition angle) and thin film morphology of tantalum so that in future work the optical properties can be linked to the deposition parameters, which in turn can be chosen to achieve highly absorbent infrared radiation layers, e.g., for infrared sensors. It was shown that the porosity across the film thickness of both columnar and screw-like thin films is nearly constant, whereas the porosity profiles of spiral structures show a periodic pattern, the period of which seems to depend on the growth pitch.

Published
2020

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