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- ItemMetasurface design for determination of protein concentration in enzymatic reaction mixture(2023) Kuznetsova, Kateryna; Eremenko, Zoya; Pashynska, Vlada; Martynov, Artur; Kulish , Serhii; Voloshyn , YuliiaIn the paper a standard multiwell plate structure was utilized to determine the concentration of human serum albumin in water solutions and enzymatic reaction mixtures. This study marks the first application of the multiwell plate structure as a resonant metasurface unit cell through numerical simulation using the COMSOL Multiphysics software. By adjusting the operating parameters of the proposed multiwell plate (MWP) metasurface, resonance phenomena within the microwave range could be observed. The complex permittivity (CP) values of the tested solutions, obtained experimentally using the microwave dielectrometry method, were employed for the MWP metasurface modelling. The correspondence between the resonance frequency shifts of the MWP metasurface and the changes in CP values of the tested solutions was demonstrated. For the convenience of the protein concentration determination, the concentration calibration graph was proposed. Our approach enables the detection of protein concentration in the reaction mixture after 60 minutes duration of the enzymatic reaction course. The study demonstrated the customization of metasurface dimensions to enable interaction with electromagnetic waves at specific frequencies. The availability of standard multiwell plates in different sizes allows for testing solutions across various frequency ranges.
- ItemDeep Geothermal Energy for Lower Saxony (North Germany) – Combined Investigations of Geothermal Reservoir Characteristics(Amsterdam [u.a.] : Elsevier, 2014) Hahne, Barbara; Thomas, Rüdiger; Bruckman, Viktor J.; Hangx, Suzanne; Ask, MariaFor the economic success of a geothermal project the hydraulic properties and temperature of the geothermal reservoir are crucial. New methodologies in seismics, geoelectrics and reservoir geology are tested within the frame of the collaborative research programme “Geothermal Energy and High-Performance Drilling” (gebo). Within nine geoscientific projects, tools were developed that help in the evaluation and interpretation of acquired data. Special emphasis is placed on the investigation of rock properties, on the development of early reservoir assessment even during drilling, and on the interaction between the drilling devices and the reservoir formation. The propagation of fractures and the transport of fluid and heat within the regional stress field are investigated using different approaches (field studies, seismic monitoring, multi-parameter modelling). Geologic structural models have been created for simulation of the local stress field and hydromechanical processes. Furthermore, a comprehensive dataset of hydrogeochemical environments was collected allowing characterisation and hydrogeochemical modelling of the reservoir.
- ItemOn the Differential Capacitance and Potential of Zero Charge of Au(111) in Some Aprotic Solvents(Weinheim : Wiley-VCH, 2021) Shatla, Ahmed S.; Landstorfer, Manuel; Baltruschat, HelmutVoltammetric and Gouy-Chapman capacitance minimum measurements were conducted on Au(111) and roughened Au(111) electrodes in aprotic electrolytes in the absence and presence of specifically adsorbed ions for concentrations ranging from 0.001 to 0.5 M. Negative of the point of zero charge (pzc), the capacitance maximum increases in the order Ca2+
- ItemDrivers and patterns of land biosphere carbon balance reversal(Bristol : IOP Publishing, 2016) Müller, Christoph; Stehfest, Elke; van Minnen, Jelle G; Strengers, Bart; von Bloh, Werner; Beusen, Arthur H W; Schaphoff, Sibyll; Kram, Tom; Lucht, WolfgangThe carbon balance of the land biosphere is the result of complex interactions between land, atmosphere and oceans, including climatic change, carbon dioxide fertilization and land-use change. While the land biosphere currently absorbs carbon dioxide from the atmosphere, this carbon balance might be reversed under climate and land-use change ('carbon balance reversal'). A carbon balance reversal would render climate mitigation much more difficult, as net negative emissions would be needed to even stabilize atmospheric carbon dioxide concentrations. We investigate the robustness of the land biosphere carbon sink under different socio-economic pathways by systematically varying climate sensitivity, spatial patterns of climate change and resulting land-use changes. For this, we employ a modelling framework designed to account for all relevant feedback mechanisms by coupling the integrated assessment model IMAGE with the process-based dynamic vegetation, hydrology and crop growth model LPJmL. We find that carbon balance reversal can occur under a broad range of forcings and is connected to changes in tree cover and soil carbon mainly in northern latitudes. These changes are largely a consequence of vegetation responses to varying climate and only partially of land-use change and the rate of climate change. Spatial patterns of climate change as deduced from different climate models, substantially determine how much pressure in terms of global warming and land-use change the land biosphere will tolerate before the carbon balance is reversed. A reversal of the land biosphere carbon balance can occur as early as 2030, although at very low probability, and should be considered in the design of so-called peak-and-decline strategies.
- ItemNumerical analysis of the effect of nitrogen and oxygen admixtures on the chemistry of an argon plasma jet operating at atmospheric pressure([London] : IOP, 2015) Van Gaens, W.; Iseni, S.; Schmidt-Bleker, A.; Weltmann, K.-D.; Reuter, S.; Bogaerts, A.In this paper we study the cold atmospheric pressure plasma jet, called kinpen, operating in Ar with different admixture fractions up to 1% pure ${{{\rm N}}_{2}}$, ${{{\rm O}}_{2}}$ and ${{{\rm N}}_{2}}$ + ${{{\rm O}}_{2}}$. Moreover, the device is operating with a gas curtain of dry air. The absolute net production rates of the biologically active ozone (${{{\rm O}}_{3}}$) and nitrogen dioxide (${\rm N}{{{\rm O}}_{2}}$) species are measured in the far effluent by quantum cascade laser absorption spectroscopy in the mid-infrared. Additionally, a zero-dimensional semi-empirical reaction kinetics model is used to calculate the net production rates of these reactive molecules, which are compared to the experimental data. The latter model is applied throughout the entire plasma jet, starting already within the device itself. Very good qualitative and even quantitative agreement between the calculated and measured data is demonstrated. The numerical model thus yields very useful information about the chemical pathways of both the ${{{\rm O}}_{3}}$ and the ${\rm N}{{{\rm O}}_{2}}$ generation. It is shown that the production of these species can be manipulated by up to one order of magnitude by varying the amount of admixture or the admixture type, since this affects the electron kinetics significantly at these low concentration levels.