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Small villages and their sanitary infrastructure—an unnoticed influence on water quantity and a threat to water quality in headwater catchments
(2023-11-16)
In rural catchments, villages often feature their own, separate urban water infrastructure, including combined sewer overflows (CSOs) or wastewater treatment plants (WWTPs). These point sources affect the water quantity and quality of the receiving low order streams. However, the extent of this impact is rarely monitored. We installed discharge and water quality measurements at the outlet of two small, neighbouring headwater catchments, one that includes a village, a WWTP, and two CSOs, while the other is predominantly ...
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FTIR spectroscopy and multivariate discriminant analysis for classifying bituminous mastics: Exploring aging states and mastic composition
(2024-07-02)
This study aimed to differentiate among various bituminous mastics through the analysis of FTIR spectroscopy data. The mastics, incorporating three filler types, a 50/70 penetration index binder, and foamed bitumen, underwent chemical examination via FTIR spectroscopy after exposure to various aging cycles. Employing different multivariate discriminant analysis approaches, the investigation identified an optimal method, i.e., PLSR-LDA, which achieved a prediction precision of 100 % in distinguishing between various ...
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Seasonal variation in heavy metal intake and excretion by dairy cattle in an Indian megacity
(2024-06-10)
Milk consumption plays a pivotal role in human nutrition, especially for children, due to its high protein, calcium, and vitamin contents that aid cognitive development. Nonetheless, potential hazards from heavy metal presence in milk, due to environmental exposure and intake through feed, have gained global attention. Given paucity of data we investigated the seasonal variation in the quantitative intake of heavy metals (cadmium: Cd, chromium: Cr, lead: Pb) by dairy cows in the South Indian megacity of Bengaluru, ...
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Fluorescence microscopic investigation of PCE superplasticiser adsorption in calcined clay blended cement
(2024-03-31)
Global efforts to minimise carbon dioxide emissions are also leading to attempts to use calcined clays (CC) as a partial substitute for cement in concrete. While the hydration mechanism of such CC blended cements is now well understood, the range of effective admixtures like polycarboxylate ethers (PCE) is limited. There are PCE types that promise relatively high effectiveness, but the mechanisms of action are not yet sufficiently understood. For a detailed understanding of the adsorption of such PCEs, spatially ...
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Water quality footprint of agricultural emissions of nitrogen, phosphorus and glyphosate associated with German bioeconomy
(2023-11-02)
Fertiliser and pesticide application can cause extensive environmental damage. We use the water quality footprint to express nitrogen, phosphorus and glyphosate emissions from agriculture in volumes of water needed to virtually dilute pollution and apply the approach to agricultural imports for the German bioeconomy in 1995 and 2020. In total, the virtual German water quality footprint corresponds to 90 times the volume of Lake Constance. If water pollution had to be eliminated by dilution in export countries supplying ...
Aufsatz
Optimization of the bicinchoninic acid assay for quantifying carbohydrates of soil extracellular polymeric substances
(2023-12-23)
Background and aims
The bicinchoninic acid (BCA) method was not yet applied on soil extracts of extracellular polymeric substances (EPS) to quantify polysaccharides, although this might be possible by introducing a cleavage step to produce monosaccharides. A pre-extraction with CaCl₂ to remove interfering substances is usually performed before extracting EPS. The main objective of this study was to optimize the BCA assay for total carbohydrates quantification by applying a hydrolysis step to the EPS extracts, while ...
Aufsatz
Correlation between the activation energy of PLA respectively PLA/starch composites and mechanical properties with regard to differ accelerated aging conditions
(2024-02-22)
Within this research semi-crystalline polylactide and composites with 50 wt.% native potato starch were compounded and injection molded. The material was mechanically characterized by tensile, three-point bending, and Charpy impact tests. These tests were carried out in the freshly molded state and after 332 and 792 h of storage at accelerated temperature or humidity. The respective activation energy was calculated by applying the Flynn-Wall-Ozawa method. The focus of the study was to investigate the correlation ...
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Modelling competitive adsorption of organic micropollutants onto powdered activated carbon in continuous stirred tank reactors for advanced wastewater treatment
(2024-05-21)
This work investigates the validation and application of a competitive model approach for full-scale wastewater treatment plants (WWTP) with external recirculation of partially loaded powdered activated carbon (PAC) for removal of organic micropollutants (OMP). It is based on the ideal adsorbed solution theory (IAST) for multisolute mixtures combined with calibration of fictive organic components and correction of single-solute model parameters for OMP by use of the tracer model (TRM). Adsorption kinetics are represented ...
Aufsatz
Validation of cognitive load during inquiry-based learning with multimedia scaffolds using subjective measurement and eye movements
(2021-08-31)
Subject-method barriers and cognitive load (CL) of students have a particular importance in the complex learning process of scientific inquiry. In this work, we investigate the valid measurement of CL as well as different scaffolds to reduce it during experimentation. Specifically, we examine the validity of a subjective measurement instrument to assess CL [in extraneous cognitive load (ECL), intrinsic cognitive load, and germane cognitive load (GCL)] during the use of multimedia scaffolds in the planning phase of ...
Aufsatz
The Effect of Pre-Drying Treatment and Drying Conditions on Quality and Energy Consumption of Hot Air-Dried Celeriac Slices: Optimisation
(2021-07-29)
Celeriac is a good source of fibre, trace minerals, and phenolic compounds; it has a pleasant aroma but is a perishable material, prone to discolouration. This research investigated the optimisation of the quality and energy demand in hot-air dried celeriac slices. The experiment utilised the I-optimal design of response surface methodology with 30 experiment runs. Pre-drying treatments (blanching at 85 °C, three minutes; dipping in 1% citric acid solution, three minutes; no pre-drying treatment), drying temperatures ...