Gewichtung von Einflussfaktoren auf die initiale Nassfestigkeit von Papier. Dissertation

Aus dem Inhalt: Die vorliegende Arbeit entstand im Zeitraum von Oktober 2010 bis Mai 2016 in Kooperation zwischen der Hochschule für angewandte Wissenschaften München, Fakultät 05 und der Universität Hamburg, Fakultät MIN, Fachbereich Biologie. Die Arbeiten erfolgten im Rahmen des Projektes "Initiale Nassfestigkeit", gefördert von der Bayrischen Forschungsstiftung (Förderkennzeichen AZ 1000-11).Enthält 4 Fachartikel aus dem Forschungsprojek

Weighing of different impact factors on wet web strength by full-factorial design of experiments

The wet web strength is one of the most important parameters for effective paper machine performance. A huge variety of parameters is known from many studies to have an impact on the wet web strength (WWS). In this study, a full factorial design of experiments (DOE) was used to determine the effect of different factors on the WWS. The goal was to use a DOE method within the field of paper strength research to acquire advanced information on the mechanisms of strength development at different dryness levels. The study was carried out with laboratory handsheets made of commercial unbleached softwood pulp, which was refined in a laboratory Hollander beater. The WWS was measured according to the German standard DIN 54514. The analysis of the data showed that weighing of the influencing factors on WWS is possible, which may lead to a better understanding of paper strength development mechanisms at low dryness levels. The applied method was proven to be reliable for the determination of the impact of various factors and will therefore be used in future work

Chemisch-physikalische Wechselwirkungen und deren Einfluss auf die initiale Nassfestigkeit. 3. Darmstädter Papierchemie-Kolloquium 09. Mai 2014; [Vortrag]

enth. Literaturverzeichni

Demonstration of Strength Development in Initial Wet Paper Web using Field Emission-Scanning Electron Microscopy (FE-SEM)

Various models exist that explain strength development in the wet web. Furthermore the scanning electron microscope (SEM) has been used in the paper industry to characterise cellulosic fibres and paper. The documentation of the initial wet web properties needs very specific requirements for sample preparation. An SEM image shows the sample´s surface, so the wet sample’s water film would cover all fine fibre structures. For this reason the samples must be dried prior to analysis. Freeze drying is a common method that is described to prepare samples for characterisation of single fibres before and after mechanical treatment. In this investigation the structure of the initial wet web was physically fixed by rapid freezing, followed by freeze drying. Afterwards, the samples were analyzed by Field Emission SEM (FE-SEM). The generated images support the hypothesis that fibrils partially extend themselves from the fibre and interact with adjacent fibres

Leimungswissen: Harzleim-AKD-ASA. Aus der Forschung für die Praxis ; Wet-End-Prozesse: Effizienter Einsatz chemischer Additive, Papiertechnische Stiftung, München. 17.03.2015

enth. Abstrac

Guided chroma reconstruction for screen content coding

In professional markets, there is a growing need to incorporate off-the-shelf consumer-level hardware to reduce costs and speed up development. Typically, these hardware components contain hardware-accelerated video encoders, which are limited to the more popular YUV4: 2: 0 profiles. For screen content coding (SCC) (e.g., desktop sharing, supervisory control and data acquisition applications, etc.), chroma subsampling can produce specific artifacts that are disturbing in high-quality professional applications. Current research on SCC focuses on developing specific screen content profiles and coding tools, which are not likely to be integrated in consumer electronics. In this paper, a method is explored to improve the chroma quality of SCC using YUV4: 2: 0 codecs. It is possible to recover parts of the chroma component based on the luma component and the subsampling filter that is used at the encoder device. A 1.63-dB peak signal-to-noise ratio-chroma improvement and 0.051 structural similarity-chroma improvement are measured on average for screen content sequences. The proposed method still provides improvements if compression is used