A5054515877- Catalysis for Biomass Conversion
- Innovative Microfluidic and Catalytic Techniques Innovation
- Catalysis and Hydrodesulfurization Studies
- Enzyme Catalysis and Immobilization
- Microbial Metabolic Engineering and Bioproduction
- Terahertz technology and applications
- Biofuel production and bioconversion
- Catalytic Processes in Materials Science
- Biodiesel Production and Applications
- Superconducting and THz Device Technology
- Microwave and Dielectric Measurement Techniques
- Advanced SAR Imaging Techniques
- Surface Chemistry and Catalysis
- Nanomaterials for catalytic reactions
- Lattice Boltzmann Simulation Studies
- Spectroscopy and Quantum Chemical Studies
- Microwave Imaging and Scattering Analysis
- Process Optimization and Integration
- Heat and Mass Transfer in Porous Media
- Radar Systems and Signal Processing
- Lignin and Wood Chemistry
- Microencapsulation and Drying Processes
- Microwave Engineering and Waveguides
- Seed Germination and Physiology
- Advanced Condensed Matter Physics
University of Groningen
2016-2024
Fraunhofer Institute for High Frequency Physics and Radar Techniques
2008-2017
University of Bonn
2002-2003
Abstract Biomass as a renewable and abundantly available carbon source is promising alternative to fossil resources for the production of chemicals fuels. The development biobased chemistry, along with catalyst design, has received much research attention over recent years. However, dedicated reactor concepts conversion biomass its derivatives are relatively new field. Continuous flow microreactors tool process intensification, especially reactions in multiphase systems. In this work,...
The hydrogenation of levulinic acid (LA) to γ-valerolactone (GVL) was performed in perfluoroalkoxy alkane capillary microreactors packed with a carbon-supported ruthenium (Ru/C) catalyst an average particle diameter 0.3 or 0.45 mm. reaction executed under upstream gas–liquid slug flow 1,4-dioxane as the solvent and H2 hydrogen donor gas phase. Operating conditions (i.e., rate liquid ratio, pressure, temperature size) were varied microreactor determine influence mass transfer kinetic...
Lignin is a promising feedstock for the replacement of conventional carbon sources production chemicals and fuels. In this paper, results are reported depolymerization various residual lignins in absence catalyst by utilizing ozone. Reactions were performed microreactor setup ensuring high gas–liquid mass transfer rates, low inventory ozone, straightforward scale-up possibilities. The ozonation demonstrated using representative model compound (vanillin) (pyrolytic organosolv) dissolved...
Oxidation of 5-hydroxymethylfurfural (HMF) using air or pure oxygen was performed in polytetrafluoroethylene capillary microreactors under gas–liquid slug flow, with Co/Mn/Br as the homogeneous catalyst acetic acid solvent. The temperature varied from 90 to 165 °C at a pressure 1 5 bar. At atmospheric conditions (and °C), acetaldehyde further added co-oxidant accelerate reaction. 150 °C, bar and residence time 2.73 min, an HMF conversion 99.2% obtained, yields 2,5-diformylfuran (DFF),...
The enzymatic esterification of oleic acid and 1-butanol to butyl oleate was performed in an aqueous–organic system capillary microreactors with various inner diameters operated under slug flow. free Rhizomucor miehei lipase the aqueous phase used as a catalyst n-heptane organic solvent. A close 100% yield could be achieved microreactor made polytetrafluoroethylene within 30 min residence time at °C. reaction rate is well described by existing kinetic model based on Ping Pong Bi mechanism...
This paper describes a mobile broadband 57 GHz - 64 FMCW radar sensor system designed to improve the situational awareness of soldiers on peacemaking or peacekeeping missions by detecting projectiles in flight. In order obtain an instantaneous coverage azimuthal field view, frequency-scanning meander antenna is used. Thereby, sensors are provisioned employ scanning principle radiating waveforms with different frequencies into separate spatial directions.
Abstract Homogeneous Co/Mn/Br catalyzed aerobic oxidation of benzyl alcohol in acetic acid to benzaldehyde was performed polytetrafluoroethylene microreactors operated under slug flow at temperatures up 150°C and pressures 5 bar. Depending on the bubble velocity length, a wetted or dewetted observed, characterized typically by complete partially wetting liquid film around body. The latter suffered from limited interfacial area for mass transfer. Experiments ca. 90°C were kinetic control...
Abstract Packed bed microreactors offer a promising platform for intensifying heterogeneously catalyzed reactions. To understand hydrodynamics therein, N 2 or water flow was investigated experimentally through packed with glass beads in this work, corresponding to microreactor particle diameter ratio ( D / d ) of 1.29–25.12. The porosity single pellet string < 1.866) agrees the literature's theoretical equation. For larger ratios, an empirical correlation is proposed address dense packing...
Fatty acid butyl esters were synthesized from sunflower oil with 1-butanol using a homogeneous Rhizomucor miehei lipase in biphasic organic (triglyceride, 1-butanol, hexane)- water (with enzyme) system continuous setup consisting of cascade stirred tank reactor and centrifugal contactor separator (CCCS), the latter being used for integrated reaction liquid-liquid separation. A fatty ester yield up to 93% was obtained when operated once-through mode. The run 8 h without operational issues....
The following paper describes the development of an autonomous and compact millimeter wave scanning measurement system (SAMMI - Stand Alone Millimeter Imager) which works in W-Band (CW@78GHz). SAMMI <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">®</sup> was developed to demonstrate high potential usability region for material classification[1].
Abstract. While optical cameras or laser systems are widely used for mobile mapping low attention was payed radar systems. Due to new semiconductor technologies, compact and leight weight SAR based on the Frequency Modulated Continuous Wave (FMCW) principle in millimeter wave domain can serve cars. For of long stripes along roads close range a special strategy focusing images developed. Hereby local adapted planes processing considering IMU data sensor. An experimental system designed high...
The radar warning and information system for applications in disaster management (RAWIS) is being designed constructed a consortium comprising eight partners. It intended civil protection will support emergency teams engaged complex mission contexts. This paper gives an overview of the overall project addresses some aspects sub-projects.
The characterization of materials is one major task for systems which work e.g. in the field quality or production control. One factor to analyze material volume information permittivity. following paper describes a measurement method determine and gives an overview about system. In addition first results will be shown.
The characterization of materials in the millimeter wave frequency range offer many new applications for quality control and security applications. This paper shows results different with a real aperture scanning system between 75 GHz - 325 amplitude phase.
The Aim of this study was to monitor the chlorophyll and water content plants with THz-time-domain-spectroscopy. This technique provides ability gather frequency phase data within all dielectric molecular information needed recalculate concentration.
Millimeterwaves and terahertz sensors can cover a broad field of applications ranging from production control to security scanners. The outstanding features are the transparency many materials like textiles, paper plastics in this frequency region, good contrast any humid or dense dielectric material capability employ miniaturized RF systems small antenna apertures probes. A stand-alone-millimetre-wave-imager, SAMMY, was developed built, demonstrate part electromagnetic spectrum for inspection.