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Aufsatz
Performance comparison of a fixed-bed solar grain dryer with and without latent heat storage
(2024-04-21)
Latent heat storage has gained attention as an energy storage method for solar drying due to its high storage density. However, its overall impact in drying performance has not been sufficiently investigated. This study presents detailed, validated mathematical models necessary for the transient simulation of a solar dryer with latent heat storage with the aim of assessing the effect that such storage has on the deep bed drying of wheat. Computer simulations were run with weather data from Germany. A fixed bed dryer ...
Aufsatz
Boundary Work Tactics and Their Effects on Information and Communication Technology Use After Hours and Recovery
(2023-10-16)
With an increasing use of work-related technologies after hours and mobile working, boundaries between work and personal life domains blur more and more, impairing recovery. Qualitative studies have shown that individuals use various boundary work tactics to actively manage their work–nonwork boundaries. However, it remains largely unknown how the use of such tactics contributes to recovery. This research differentiates types of availability-related boundary work tactics and organizes them according to their underlying ...
Aufsatz
Development and Process Integration of an Alternative Demoulding System for High-Pressure Die Casting Using a Contoured Vacuum Mask
(2024-06-11)
This study presents the development and process integration of an alternative demoulding system for high-pressure die casting. The system is aimed at the removal of large structural castings, which are becoming increasingly popular in the industry under the terms mega- and gigacasting. The development differs from conventional systems in the fact that it completely avoids ejectors and realises the demoulding via the principle of vacuum suction cups. Preliminary tests were carried out in which various established ...
Aufsatz
Soil contribution to the cobalamin (vitamin B12) supply of terrestrial organisms
(2024-05-09)
Cobalamin (Vitamin B12) is a cofactor for many enzymes, including those in bacteria, archaea, algae, and mammals. In humans, cobalamin deficiency can lead to pernicious anaemia as well as gastrointestinal and neurological disorders. In contrast to marine ecosystems, there is a great paucity of information on the role of soils and terrestrial plants in the supply of cobalt and cobalamin to microorganisms and animals. The content of cobalt cations in most soils is usually sufficient to maintain growth, and the density ...
Aufsatz
Transformation and Leaching Simulation of 6:2 and 8:2 diPAP and Related Metabolites in Unsaturated Soil Column Studies with MACRO
(2023-10-14)
PFAS (perfluoroalkyl substances) are widespread in the environment and are found in almost every medium. Besides persistent PFAS, their transforming precursors gained attention since they may be a reservoir for persistent PFAS in soil. Only little information is available about the behavior of these precursors and the simultaneous leaching of their transformation products. However, this information is urgently needed to improve estimates of contamination levels. For this purpose, two precursors and their non-degradable ...
Aufsatz
Pectin forms polymeric pigments by complexing anthocyanins during red winemaking and ageing
(2024-05-05)
The long-term stability of red wine color depends on the formation of polymeric pigments from anthocyanins. Although there is still a lot of uncertainty about the specific structure of this diverse group of pigments, there is consensus that they are reaction products of anthocyanins and other polyphenols. Interactions between anthocyanins and pectic polysaccharides have been suggested to stabilize anthocyanins. This study explores the impact of such interactions by adding pectin during red winemaking. The results ...
Aufsatz
Galactosamine and mannosamine are integral parts of bacterial and fungal extracellular polymeric substances
(2024-03-22)
Extracellular polymeric substances (EPS) are produced by microorganisms and interact to form a complex matrix called biofilm. In soils, EPS are important contributors to the microbial necromass and, thus, to soil organic carbon (SOC). Amino sugars (AS) are used as indicators for microbial necromass in soil, although the origin of galactosamine and mannosamine is largely unknown. However, indications exist that they are part of EPS. In this study, two bacteria and two fungi were grown in starch medium either with or ...
Aufsatz
“Stop crying your heart out”: how failed founders can use emotional failure narratives
(2023-06-07)
Failed founders experience very intense emotions resulting from their entrepreneurial failure. Since many founders are not discouraged by failure and consider founding a subsequent startup, the need to deal with the stigma attached to failed founders. Applying an experimental research design, this study investigates how failed founders can use emotional failure narratives to approach potential co-founders for their subsequent venture project. We demonstrate that the use of failure narratives that contain both negative ...
Aufsatz
Machine learning parameter systems, Noether normalisations and quasi-stable positions
(2024-06-25)
We discuss the use of machine learning models for finding “good coordinates” for polynomial ideals. Our main goal is to put ideals into quasi-stable position, as this generic position shares most properties of the generic initial ideal, but can be deterministically reached and verified. Furthermore, it entails a Noether normalisation and provides us with a system of parameters. Traditional approaches use either random choices which typically destroy all sparsity or rather simple human heuristics which are only ...
Aufsatz
Investigations of lightweight concrete by in situ compression tests using high-resolution computed tomography (μ-CT)
(2024-02-24)
The fracture behaviour of concrete is studied in various micro- and macrodamage models. This is important for estimating serviceability and stability of concrete structures. However, a detailed understanding of the material behaviour under load is often not available. In order to better interpret the fracture behaviour and pattern, images of lightweight concrete were taken using a highresolution computed tomography (μ-CT) scanner. The samples were loaded between the taken images and the load was kept constant during ...