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In this study, feasibility of selected nutrient sequestration during hydrothermal carbonization (HTC) was tested for three different HTC temperatures (180, 230, and 300 °C). To study the nutrient sequestration in solid from liquid solution, sugar and salt solutions were chosen as HTC feedstock. Glucose was used as carbohydrate source and various salts e.g., ammonium hydrophosphate, potassium chloride, potassium sulfate, and anhydrous ferric chloride were used as source of nitrogen and phosphorus, potassium, and iron, respectively. Solid hydrochar was extensively characterized by means of elemental, ICP-OES, SEM-EDX, surface area, pore volume and size, and ATR-FTIR to determine nutrients’ sequestration as well as hydrochar quality variation with HTC temperatures. The spherical mesoporous hydrochars produced during HTC have low surface area in the range of 1.0–3.5 m2 g?1. Hydrochar yield was increased about 10% with the increase of temperature from 180 °C to 300 °C. Nutrient sequestration was also increased with HTC temperature. In fact, around 71, 31, and 23 wt% nitrogen, iron, and phosphorus were sequestered at 300 °C, respectively. Potassium sequestration was very low throughout the HTC and maximum 5.2% was observed in solid during HTC.

AbstractAlthough the road-map of the oxy-fuel process seems to be very advanced, there are still plenty of open questions. One of the significant ones is the corrosive behaviour of the heat exchanger surfaces. The Institute of Combustion and Power Plant Technology, University of Stuttgart, performs research on the fireside corrosion under oxy-fuel and conventional combustion conditions for the current and supercritical power plants considering the influence of combustion modus, gas atmosphere and fly ash deposits on the waterwall and superheater surfaces. Since the oxy-fuel-combustion atmosphere is composed of recirculated flue gases and pure oxygen, significantly higher concentrations of CO2, SO2 and H2O are present compared to the conventional combustion of coal with air as an oxidizer. In the here presented study the influence of an oxy-fuel combustion of a hard-coal on the surface of selected superheater materials is discussed and compared to the results obtained for lignite. Especially the interactions between the flue gas atmosphere, ash deposits and heat exchanger materials are studied in detail. The investigation encompassed in this paper has been focused on impacts of oxide-scale growth, carbon enrichment of the materials and sulphur-induced corrosion.Increased sulphur-induced corrosion has been observed in samples exposed to the oxy-combustion atmosphere. The noticed higher depth of corrosive attack of the oxy-fuel samples might be explained by a higher partial pressure of SO2 which is characteristic for oxy-fuel process. Moreover in certain cases the sulphur might be released by the deposits. Beside that, the oxy-fuel samples were exposed to much higher partial pressures of carbon dioxide comparing to the air-case leading apparently to rapid and massive internal carbon enrichment in the oxide scale. Moreover dependence between the chromium content and oxidation ability of the austenitic materials surfaces was noticed under oxy-fuel conditions.

This contribution provides the simulated data and surrogate models for the DTU 10 MW reference wind turbine in an onshore configuration simulated with FAST v8.16.00. The dimensions include mean wind speed, turbulence intensity, and power level, as well as the application of an individual blade control (IBC) loop. Down-regulation up to 50% is considered using two controller trajectories. The constTSR trajectory considers only pitching for down-regulation, maintaining a constant tip speed ratio, and the lin70 trajectory considers both pitch and rotational speed reduction to achieve down-regulation. Power boosting is performed up to 130% power level by following the optimal Cp trajectory until the requested power level is reached. The regression is done with two methods: a spline-based interpolation and a Gaussian Process Regression (GPR). The raw data, smoothened data, and the trained GPR models are provided along with scripts for generating the surrogate model's predictions with both methods. A short description of the simulation parameters and variables considered is given in the supplementary pdf file. The dataset is part of the doctoral thesis 'Wind Turbine Operational Optimization Considering Revenue and Fatigue Objectives' by Vasilis Pettas at the University of Stuttgart (http://dx.doi.org/10.18419/opus-13959) and the journal publication 'Surrogate Modeling and Aeroelastic Analysis of a Wind Turbine with Down-Regulation, Power Boosting, and IBC Capabilities' (https://doi.org/10.3390/en17061284). Detailed analysis of the controller design and validation of the surrogate models can be found in these publications. 

Pre-trained and fine-tuned ANI models using the Gaussian Moments Neural Network (GM-NN) approach. Code for GM-NN implemented within the Tensorflow framework, including the respective documentation and tutorials, can be found on GitLab. The data represents TensorFlow v2 checkpoints and stores the metadata for the checkpoint and parameters for the model. Checkpoints can be read by the source code provided on GitLab. A detailed description for reproducing the results and employing pre-trained and fine-tuned models during a simulation is provided in the GM-NN Documentation.

AbstractThe mutant M301A of the acetylcholinesterase B from Nippostrongylus brasiliensis (NbAChE) was produced in a high‐cell‐density fermentation of a recombinant methylotrophic yeast Pichia pastoris. Dissolved oxygen (DO) spikes were used as an indicator for feeding the carbon source. Wet cell weight (WCW) reached after 8 days a maximum value of 316 g/L and the OD600 at this time was 280. The acetylcholinesterase activity increased up to 6,600 U/mL corresponding to an expression rate of 2 g of NbAChE per liter supernatant. The specific activity of the mutant NbAChE was determined after purification as 3,300 U/mg. Active site titration with chlorpyrifos, a strong AChE inhibitor, yielded in a specific activity of 3,400 U/mg. The enzyme was secreted by Pichia pastoris. Therefore, it could be concentrated from culture broth by cross‐flow‐filtration (50 kDa cut‐off membrane). It was further purified in one‐step anion‐exchange chromatography, using a XK 50/20 column filled with 125 mL Q Sepharose HP. Mutant NbAChE was purified 1.9‐fold up to a purity of 97% and a yield of 87%. The isolated enzyme was nearly homogenous, as seen on the silver stained SDS–PAGE as well as by a single peak after gel filtration. This extraordinary high expression rate and the ease of purification is an important prerequisite for their practical application, for example in biosensors for the detection of neurotoxic insecticides. © 2005 Wiley Periodicals, Inc.

AbstractThis paper presents a numerical model, which quantitatively demonstrates that ablation and partial recondensation of the dopant precursor layer are some of the dominating physical processes in laser doping (LD) of crystalline silicon. Our pulsed LD process uses a line focused laser beam, enabling the creation of solar cell emitters without the generation of dislocations, if the width w of the short axis of the line focus is w < 10 μm. The concentration profiles of the dopant atoms strongly depend on the pulse energy density Ep, the pulse to pulse separation Δx and the number of laser scans Ns. By comparing measured with modeled concentration profiles, we are able to evaluate the ablation width as well as the amount of the ablated precursor layer. In case of a sputtered phosphorus precursor layer, the ablation width wa is wa = 6 μm, whereas the width of the molten silicon layer wm is wm = 5 μm. The model also explains the dependence of experimental dopant concentration profiles on the number of subsequent laser scans Ns and pulse to pulse separation Δx. Copyright © 2010 John Wiley & Sons, Ltd.

Die Stromerzeugung aus Windenergie hat in den vergangenen Jahren, insbesondere unterstützt durch das Erneuerbare-Energien-Gesetz (EEG), stark zugenommen und belief sich im Jahr 2006 auf einen Anteil von rund 4,8 % an der Bruttostromerzeugung. Aufgrund des fluktuierenden Charakters der Windstromerzeugung ist die Integration und Einspeisung dieses Anteils in das Netz der öffentlichen Versorgung bereits heute mit teilweise erheblichen Problemen verbunden. Diese werden sich in Zukunft weiter verstärken, wenn der geplante Einstieg in die Offshore-Windenergienutzung wie geplant stattfindet und in den kommenden Jahren einige GW Leistung Offshore installiert werden. Grundsätzlich bieten sich zwei Lösungsansätze für die angesprochene Problematik an, die sich gegenseitig ergänzen: Zum einen können durch exaktere Prognoseverfahren die zu erwartenden Windstrommengen besser vorhergesagt und damit zugleich die Fahrpläne der konventionellen (Schatten-)Kraftwerke genauer erstellt werden. Der Bedarf an Ausgleichsenergie wird durch dieses Verfahren minimiert. Im Fall von Windflauten muss jedoch die gesamte nachgefragte Leistung durch konventionelle Kraftwerke bereitgestellt werden. Zum anderen kann durch den Einsatz von Speicherkraftwerken eine zeitliche Entkopplung von Energieangebot und –bedarf realisiert werden, indem in Zeiten hohen Windenergieangebots ein Teil des Windstroms zwischengespeichert wird und umgekehrt in Windflauten das Speicherkraftwerk die Strombereitstellung übernimmt. Mit Hilfe dieses Verfahrens erfolgt dementsprechend eine Anpassung des Angebots an die Nachfrage. Die vorliegende Arbeit konzentriert sich auf den zweiten Ansatz und entwickelt ein Simulationsmodell, mit dessen Hilfe ein Windpark-Speicher-System abgebildet und eine Vergleichmäßigung des Windstroms durch Integration verschiedener Speichertechnologen (diabates/adiabates Druckluft-Speicherkraftwerk, Pumpspeicherkraftwerk) simuliert wird. Ziel der Vergleichmäßigung ist die kontinuierliche Bereitstellung einer garantierten Leistung. Die verbleibenden Fluktuationen werden durch einen Abgleich mit der Nachfrageseite in Form der Netzlast berücksichtigt. Für unterschiedliche Systemvarianten werden sowohl die Stromgestehungskosten als auch die spezifischen CO2-Emissionen berechnet, um auf dieser Basis einen Vergleich der einzelnen Systeme zu ermöglichen. Grundlegende Parameter wie beispielsweise die energetische Speicherkapazität, die spezifischen Investitionskosten der Windenergieanlagen und des Speicherkraftwerks oder auch die Bezugskosten für Ausgleichsenergie werden anschließend in Form von Sensitivitätsanalysen und Parametervariation detailliert untersucht. Auf diese Weise können die unter konstant gesetzten Parametern gewonnenen Ergebnisse bestätigt bzw. kritisch hinterfragt werden, wobei insbesondere der Einfluss der verschiedenen Eingangsgrößen auf die Stromgestehungskosten im Detail analysiert wird. In der Folge werden vielversprechende Systemkonfigurationen unter dem Zielkriterium möglichst geringer Stromgestehungskosten identifiziert. Zudem wird geprüft, welche Anforderungen an die Kostenentwicklung speziell von Druckluft-Speicherkraftwerken zu stellen sind, um mit einem konventionellen Vergleichssystem konkurrenzfähig zu werden. Power generation from wind energy has increased significantly in the past years reaching 4.8 % of the gross power generation. This development was especially promoted by the re-newable energy law (Erneuerbares-Energien-Gesetz). The integration and feed-in of this power into the grid is associated with considerable problems as the wind power generation is characterised by its fluctuating nature. These diffi-culties will grow and accelerate if the planned wind parks in the North or Baltic Sea with some GW power are realised in the following years. In principle there are two methods of resolution for this kind of problem which com-plement one another: On the one hand it’s possible to develop better forecasting models in order to forecast the wind power generation more accurately. By this means also the operation of the conventional power plants can be planned more accurately. In the consequence the de-mand for balancing power is minimized. Nevertheless it’s inevitable to provide the total sum of demanded power in times of wind calms by conventional power plants. Concerning the second method the operation of storage facilities is involved in the system in order to realise a temporal decoupling of energy supply and demand. In times with high wind power generation the storage unit is filled and vice versa in wind calms the storage facility is able to provide power. Thus the supply side is adapted to the demand side. The following thesis focuses on the second method. A tool is developed, simulating the operation of a windpark-storage system, in order to equalise the wind power generation by the help of different storage technologies (diabatic/adiabatic compressed air energy storage, pumped hydro). The equalisation aims at the continuous supply of a guaranteed power. Re-maining fluctuations of wind power are considered by a comparison of demand and supply side, whereas the demand side is represented by the system load. The costs of generating electricity as well as the specific CO2-emissions are calculated for different configurations resulting in a comparison of the different systems. Following fun-damental parameters as the energy storage capacity, the specific investment costs of the wind power plants and the storage facility or the price of balancing power are examined in detail by the help of a sensitivity analysis. In so doing it is possible to confirm or to question the results calculated with fixed parameters. In this context especially the influence of different parame-ters on the costs of generating electricity is analysed. Finally promising system configurations with the aim of reducing the costs of generat-ing electricity are identified. Moreover the requirements concerning the reduction of invest-ment costs especially of compressed air energy storage systems in order to achieve competi-tiveness with a conventional system are examined.

An investigation of the Schottky barrier formation between iridium, iridium oxide films, and n-Si, n-GaAs substrates and its implications for oxygen evolution from water is presented. Iridium and iridium oxide films of 20-nm thickness were sputtered on single-crystalline n-Si and n-GaAs substrates. Schottky barrier heights reached values of 0.9 eV (Si) and 1.1 eV (GaAs) as determined by impedance measurements. Forward currents were usually not limited by the thermal emission model (n>or=2). EBIC data are presented in order to demonstrate the homogeneity of the surface coating. IrO/sub 2/-coated electrodes were investigated as photoanodes for oxygen evolution from aqueous electrolytes. The stability is better with silicon as substrate and comparable to literature data. Since IrO/sub 2/ does not dissolve electrochemically, but peels off only at impurities at the solid-state interface, stability is expected to improve under purer deposition conditions for the IrO/sub 2/ coating. >