Rapid Aging as a Key to Understand Deactivation of Ni/Al2O3 Catalysts Applied for the CO2 Methanation

Catalysis Letters - We developed a rapid aging method for Ni/Al2O3 methanation catalysts mimicking the real aging in the actual application. The method is based on hydrothermal deactivation of the...     

Experiencing CSCL: from motivation to the embodied experience and beyond

International Journal of Computer-Supported Collaborative Learning -     

Building community together: towards equitable CSCL practices and processes

International Journal of Computer-Supported Collaborative Learning -     

Beyond economics—understanding the decision-making of German small private landlords in terms of energy efficiency investment

The German government aims to achieve virtually climate-neutral building stock by 2050 to tackle climate change. To realise this goal, comprehensive policy packages based on neoclassical economic theory are in place to foster energy efficiency investment. However, in the building sector, there is increasingly a gap between this aspiration and the reality. It is claimed that one of the main reasons for this is that the existing policy framework fails to address the specific characteristics and needs of different groups of building owners. This is a particular challenge in Germany, where 80% of all dwellings are owned privately and 37% are rented out by small private landlords (SPL). Despite the significant numbers of SPL, they often follow black box decision-making processes when considering energy renovations. In this study, the author uses an explanatory model to understand the decision-making processes of SPL, combining theoretical aspects from different research disciplines. This model was applied to a low-demand housing market in a neighbourhood in the Ruhr area. Eighteen semi-structured interviews (each lasting between 37 and 115 min) were conducted, demonstrating that in addition to economic factors, the values, beliefs, norms and routines of SPL—as well as their personal capabilities and contextual factors—play an important role in their decision-making. Based on the findings, recommendations are made for enhancing the effectiveness of existing energy efficiency policies and other supporting instruments (e.g. tenancy law and social legislation), tailored to the specific needs of SPL.     

A flexible air separation process: 1. Design and steady-state optimizations

The flexible operation of energy-intensive processes, such as cryogenic air separation, has economic potential due to increasing fluctuations of the electricity markets. Multiproduct air separation processes with high ratios of liquid product are very promising for flexible operation due to storable products. We present a process design with an integrated liquefication cycle and liquid assist operation, that facilitates a high liquid product ratio and a flexible process operation. We use a mechanistic dynamic process model in steady-state process optimizations covering the wide operational range of the proposed process. The optimization results show that the power demand can be varied in a range from 3.5 to 28 MW without violating operational constraints by changing the nitrogen and oxygen production rates. Thus, the proposed process is a promising air separation candidate for flexible operation with respect to fluctuating electricity markets.     

Selective Delivery of Doxorubicin to EGFR+ Cancer Cells by Cetuximab–DNA Conjugates

Doxorubicin is a hydrophobic anticancer drug that has poor selectivity, due to the lack of active targeting capability. Here, learning lessons from the success of antibody–drug conjugates, we have designed a new doxorubicin delivery system without conjugating doxorubicin to antibody directly. In this setup, cetuximab, an antibody that targets the epidermal growth factor receptor (EGFR) in cancer cells, was conjugated to a single-stranded DNA with a carefully designed sequence in a site-selective manner by using the DNA-templated protein conjugation (DTPC) method. The DNA duplex in the conjugates serves as a carrier of doxorubicin through noncovalent intercalation, and cetuximab functions as the targeting agent; this could drastically decrease systemic toxicity and potentially avoid under- or overdosing. The size of conjugates loaded with doxorubicin was about 8.77 or 16.61 nm when characterized by dynamic light scattering and atomic force microscopy, respectively. In vitro cytotoxicity and selective cancer cell killing was investigated against two EGFR⁺ cell lines (KB and MDA-MB-231) and one EGFR⁻ cell line (NIH-3T3). Cytotoxicity and flow cytometry data showed that doxorubicin loaded in cetuximab–DNA conjugates was more potent in terms of cell cytotoxicity than free doxorubicin in EGFR-overexpressed cell lines, thus suggesting that the conjugates were more selectively and easily taken up into cells, followed by rapid release of doxorubicin from the system into the cytoplasm from endosomes.     

Hot corrosion of TBC-coated components upon combustion of low-sulfur fuels

Gas turbine reliability is a crucial requirement for passenger safety in aviation and a secure energy supply. Hence, corrosive degradation of combustor parts, vanes, and blades in gas turbines must be prevented. One of the most severe forms of corrosion is alkali-sulfate-induced hot corrosion, which is associated with internal sulfidation of components and is usually anticipated to fade in importance in the absence of sulfur. However, the literature suggests that hot corrosion might still occur in low-sulfur combustion gases. In this study, established thermodynamic modeling methods are used to analyze the low-sulfur hot corrosion regime. Liquid sodium chromate is found to be stable in these conditions. A comparison of calculation results and engine findings suggests that high alkali levels can negatively impact thermal barrier coating life even if sulfur is absent in the fuel. Laboratory tests are carried out to validate the chromate formation on MCrAlY-coated specimens. It is shown that molten sodium chromate can alter the oxidation behavior of MCrAlY, promoting the formation of voluminous spinel. This represents a new and different form of hot corrosion compared to type I hot corrosion.