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    Microwave plasma discharges for biomass pretreatment: Degradation of a sodium carboxymethyl cellulose model
    (New York, NY : American Inst. of Physics, 2020) Honnorat, B.; Brüser, V.; Kolb, J.F.
    Biogas production is an important component of an environmentally benign renewable energy strategy. However, the cost-effectiveness of biogas production from biomass is limited by the presence of polymeric structures, which are recalcitrant to digestion by bacteria. Therefore, pretreatments must often be applied prior to anaerobic fermentation to increase yields of biogas. Many physico-chemical pretreatments have a high energy demand and are generally costly. An alternative could be the ignition of a plasma directly in the biomass substrate. The reactive species that are generated by plasma-liquid interactions, such as hydroxyl radicals and hydrogen peroxides, could contribute significantly to the disintegration of cell walls and the breakage of poorly digestible polymers. With respect to economic, processing, and other potential benefits, a microwave instigated and sustained plasma was investigated. A microwave circuit transmitted 2-kW pulses into a recirculated sodium carboxymethyl cellulose solution, which mimicked the rheological properties of biomass. Each microwave pulse had a duration of 12.5 ms and caused the ignition of a discharge after a vapor bubble had formed. Microwaves were absorbed in the process with an efficiency of ∼97%. Slow-motion imaging showed the development of the discharge. The plasma discharges provoked a decrease in the viscosity, probably caused by the shortening of polymer chains of the cellulose derivative. The decrease in viscosity by itself could reduce processing costs and promotes bacterial activity in actual biomass. The results demonstrate the potential of microwave in-liquid plasma discharges for the pretreatment of biomass. © 2020 Author(s).
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    Vibrational Spectroscopic Investigation of Blood Plasma and Serum by Drop Coating Deposition for Clinical Application
    (Basel : Molecular Diversity Preservation International (MDPI), 2021) Huang, Jing; Ali, Nairveen; Quansah, Elsie; Guo, Shuxia; Noutsias, Michel; Meyer-Zedler, Tobias; Bocklitz, Thomas; Popp, Jürgen; Neugebauer, Ute; Ramoji, Anuradha
    In recent decades, vibrational spectroscopic methods such as Raman and FT-IR spectroscopy are widely applied to investigate plasma and serum samples. These methods are combined with drop coating deposition techniques to pre-concentrate the biomolecules in the dried droplet to improve the detected vibrational signal. However, most often encountered challenge is the inhomogeneous redistribution of biomolecules due to the coffee-ring effect. In this study, the variation in biomolecule distribution within the dried-sample droplet has been investigated using Raman and FT-IR spectroscopy and fluorescence lifetime imaging method. The plasma-sample from healthy donors were investigated to show the spectral differences between the inner and outer-ring region of the dried-sample droplet. Further, the preferred location of deposition of the most abundant protein albumin in the blood during the drying process of the plasma has been illustrated by using deuterated albumin. Subsequently, two patients with different cardiac-related diseases were investigated exemplarily to illustrate the variation in the pattern of plasma and serum biomolecule distribution during the drying process and its impact on patient-stratification. The study shows that a uniform sampling position of the droplet, both at the inner and the outer ring, is necessary for thorough clinical characterization of the patient’s plasma and serum sample using vibrational spectroscopy.
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    Validation of Global EUV Wave MHD Simulations and Observational Techniques
    (London : Institute of Physics Publ., 2021) Downs, Cooper; Warmuth, Alexander; Long, David M.; Bloomfield, D. Shaun; Kwon, Ryun-Young; Veronig, Astrid M.; Vourlidas, Angelos; Vršnak, Bojan
    Global EUV waves remain a controversial phenomenon more than 20 yr after their discovery by SOHO/EIT. Although consensus is growing in the community that they are most likely large-amplitude waves or shocks, the wide variety of observations and techniques used to identify and analyze them have led to disagreements regarding their physical properties and interpretation. Here, we use a 3D magnetohydrodynamic (MHD) model of the solar corona to simulate an EUV wave event on 2009 February 13 to enable a detailed validation of the various commonly used detection and analysis techniques of global EUV waves. The simulated event exhibits comparable behavior to that of a real EUV wave event, with similar kinematic behavior and plasma parameter evolution. The kinematics of the wave are estimated via visual identification and profile analysis, with both approaches providing comparable results. We find that projection effects can affect the derived kinematics of the wave, due to the variation in fast-mode wave speed with height in the corona. Coronal seismology techniques typically used for estimates of the coronal magnetic field are also tested and found to estimate fast-mode speeds comparable to those of the model. Plasma density and temperature variations of the wave front are also derived using a regularized inversion approach and found to be consistent with observed wave events. These results indicate that global waves are best interpreted as large-amplitude waves and that they can be used to probe the coronal medium using welldefined analysis techniques.
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    Wachstumskern Centifluidic Technologies, Projekt 5.3: Auswahl der Materialien, Beschichtung, Modifikation von Oberflächen : Projekt-Schlussbericht : Berichtslaufzeit: 01.10.2012 bis 31.01.2014
    (Hannover : Technische Informationsbibliothek (TIB), 2015) Polak, Martin
    Das Ziel des Projektes war die plasma-gestützte Schichtabscheidung einerseits zur Erzeugung von superhydrophoben und superhydrophilen Oberflächeneigenschaften und andererseits um die Adhäsion von Proteinen zu verbessern. Um dieses Ziel zu erreichen, wurden Niederdruck- und Atmosphärendruckplasmen zum Einsatz gebracht. Bei den Atmosphärendruckplasmen wurde darüber hinaus Quellen zur lokalen und zur flächigen Oberflächenveredelung untersucht. Sowohl die Erzeugung der superhydrophilen und superhydrophoben Oberflächeneigenschaften als auch die verbesserte Anhaftung von Proteinen konnte im Projekt erfolgreich umgesetzt werden.
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    Wachstumskern Centifluidic Technologies, Projekt: Veredelung von Komponenten für centifluidische Systeme : Projekt-Schlussbericht : Berichtslaufzeit: 01.10.2012 bis 31.01.2014
    (Hannover : Technische Informationsbibliothek (TIB), 2015) Polak, Martin
    Im Teilprojekt gab es 4 wesentliche Aufgabenpakete. - Eine zytokompatible aber zellabweisende Beschichtung, die im Temperaturbereich von -190°C bis Raumtemperatur ihre Funktion erfüllt - Die Erzeugung einer antimikrobiellen Oberflächeneigenschaft auf komplex geformten Medizinprodukten - Der Aufbau einer Plasmapolieranlage - Die Erarbeitung einer Steuerung und Prozesskontrolle für diese Plasmapolieranlage Für die ersten beiden Punkte wurden plasmagestützte Schichtabscheidungsprozesse erarbeitet, die die Anforderungen im vollen Umfang erfüllten. Für Punkt 3 und 4 wurde eine Plasmapolieranlage aufgebaut und es wurde eine Steuerung entwickelt, mit der der Polierprozess vollautomatisch durchgeführt werden kann.
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    Cold atmospheric pressure plasma and low energy electron beam as alternative nonthermal decontamination technologies for dry food surfaces: A review
    (Amsterdam [u.a.] : Elsevier Science, 2018) Hertwig, Christian; Meneses, Nicolas; Mathys, Alexander
    Background: Dry food products are often highly contaminated, and dry stress-resistant microorganisms, such as certain types of Salmonella and bacterial spores, can be still viable and multiply if the product is incorporated into high moisture food products or rehydrated. Traditional technologies for the decontamination of these products have certain limitations and drawbacks, such as alterations of product quality, environmental impacts, carcinogenic potential and/or lower consumer acceptance. Cold atmospheric pressure plasma (CAPP) and low energy electron beam (LEEB) are two promising innovative technologies for microbial inactivation on dry food surfaces, which have shown potential to solve these certain limitations. Scope and approach: This review critically summarizes recent studies on the decontamination of dry food surfaces by CAPP and LEEB. Furthermore, proposed inactivation mechanisms, product-process interactions, current limitations and upscaling potential, as well as future trends and research needs for both emerging technologies, are discussed. Key findings and conclusions: CAPP and LEEB are nonthermal technologies with a high potential for the gentle decontamination of dry food surfaces. Both technologies have similarities in their inactivation mechanisms. Due to the limited penetration depth of both technologies, product-process interactions can be minimized by maintaining product quality. A first demonstrator with Technology Readiness Level (TRL) 7 for LEEB has already been introduced into the food industry for the decontamination of herbs and spices. Compared with LEEB, CAPP is at the advanced development stage with TRL 5, for which further work is essential to design systems that are scalable to industrial requirements. © 2018 The Authors
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    Degradation of glyphosate in water by the application of surface corona discharges
    (Bristol : IWA Publishing, 2021) Zocher, Katja; Gros, Peter; Werneburg, Matthias; Brüser, Volker; Kolb, Juergen F.; Leinweber, Peter
    Glyphosate (GLP) is one of the most widely applied herbicides, and is found ubiquitously in the environment. The removal of glyphosate from waste water and soil is challenging and can be achieved with chemical or biological methods, which, nevertheless, suffer from different disadvantages. The application of a physical plasma for the removal of GLP in water was examined by the application of surface corona discharges in a wire-to-cylinder setup filled with argon. The plasma was ignited at the liquid surface without any additives. By applying a photometric method, GLP was detected after derivatisation with fluorenyl methoxycarbonyl chloride, whereas phosphate was determined with ammonium molybdate. A GLP degradation rate of 90.8% could be achieved within a treatment time of 30 minutes with an estimated energy efficiency of 0.32 g/kWh.