Refine
Year of publication
- 2024 (28) (remove)
Document Type
- Conference Proceeding (19)
- Article (7)
- Book (1)
- Master's Thesis (1)
Keywords
- Quality Management (2)
- Stadtbäume (2)
- Agri-Food Chain (1)
- Ausbreitung (1)
- Beta-blocker therapy (1)
- Betrieb (1)
- Cardiovascular (1)
- Electrocatalysis (1)
- Handwerkliche Herstellung (1)
- Klassifizierungssysteme (1)
Institute
- Fakultät AuL (28) (remove)
Water retention properties of wood fiber based growing media and their impact on irrigation strategy
(2024)
Distribution of water and air in growing media during ebb-and-flow irrigation depends on water storage properties (water retention curve) and water transport properties (hydraulic conductivity) of the materials. Growing media with their high number of coarse pores are known to exhibit strong hysteresis, i.e., differences in the water retention properties during drying and wetting cycles. To account for potential ecological disadvantages of peat, wood fibers are commonly used as substitutes for peat in growing media. However, the wood fibers generally have higher air capacities and hydraulic conductivities and lower water capacities compared to peat which may results in necessary adaptions of the irrigation strategy. Tools to optimize irrigation systems are physically based water transport models, such as HYDRUS-1D, which is commonly used to describe water transport in soils, but not often for growing media. In this study, white peat and pure wood fibers were used to describe differences in their water retention behavior. Water retention curves (drying cycles) and hydraulic conductivities were measured with standard analytical procedures. Hysteresis of the water retention curves was analytically determined based on their capillary rise properties. The results were used with a modified HYDRUS-1D model to test model quality against measured water contents during ebb-and-flow irrigation cycles and to optimize the irrigation strategy for the different materials. The results showed that the model quality was sufficiently good only if the strong hysteresis of the water retention curves was considered during the simulation process. Different strategies were tested to modify ebb-and-flow irrigation (irrigation frequency, irrigation duration and irrigation height) in that way that the water suction in the root zone was similar to that of the peat material. Simulation results showed that significant improvements could only be reached by increasing the flooding depth in ebb-and-flow systems to ensure an optimum water supply of plants in the wood fiber based growing media.
The development of base metal electrodes that can act as active and stable oxygen generating electrodes in water electrolysis systems, especially at low pH levels, remains a challenge. The use of suspensions as electrolytes for water splitting has until recently been limited to photoelectrocatalytic approaches. A high current density (j=30 mA/cm2) for water electrolysis has been achieved at a very low oxygen evolution reaction (OER) potential (E=1.36 V vs. RHE) using a SnO2/H2SO4 suspension-based electrolyte in combination with a steel anode. More importantly, the high charge-to-oxygen conversion rate (Faraday efficiency of 88% for OER at j=10 mA/cm2 current density). Since cyclic voltammetry (CV) experiments show that oxygen evolution starts at a low, but not exceptionally low, potential, the reason for the low potential in chronoamperometry (CP) tests is an increase in the active electrode area, which has been confirmed by various experiments. For the first time, the addition of a relatively small amount of solids to a clear electrolyte has been shown to significantly reduce the overpotential of the OER in water electrolysis down to the 100 mV region, resulting in a remarkable reduction in anode wear while maintaining a high current density.
Test von Schnellverfahren zur Bestimmung der Benetzungseigenschaften von Kultursubstraten (Abstract)
(2024)
Durch die Auswirkungen des Klimawandels – besonders durch Hitze – geraten viele indigene Baumarten innerhalb der nächsten 75 Jahre voraussichtlich an den Rand ihrer Existenz. Der Stadtstandort stellt eine zusätzliche Herausforderung dar, der durch menschliche Aktivitäten negativ, aber auch positiv beeinflusst werden kann. Besonders die Wasserverfügbarkeit kann durch geeignete vegetationstechnische Maßnahmen und intelligente Profilierung von Oberflächen befördert werden. Die Vegetation wird sich verändern. Mit gebietseinheimischen Genotypen und natürlicher Migration hitzeverträglicher Arten alleine lassen sich unsere Probleme nicht lösen. Wir brauchen Bäume in der Stadt, die beschatten und verdunsten.
Lösungsansätze sind die vielfältige Anpflanzung hitzeresistenter Genotypen indigener Arten, neuer, submediterraner Arten aus Süd- und Südosteuropa (assisted migration) sowie klimatoleranter Arten anderer Kontinente. Es ist allerdings davon auszugehen, dass sich diese Arten dann bei uns auch etablieren werden. Und das ist bei der durch die Eiszeiten verarmten Gehölzflora Mitteleuropas und für lebenswerte Städte auch gut so!
Response of petunia to wood fibre amended peat substrate under ebb-and-flow irrigation (Abstract)
(2024)
The objective of this article is to prepare for the initial certification according to IFS Global Markets Food V3 at the Landshuter Brauhaus AG private brewery at the Ellermühle site, which is expected in August 2025, and to create the basis for a potential follow-up certification according to IFS Food. The IFS Global Markets Food Program V3 is a standardized, voluntary and non-accredited assessment program for food companies, both for retail and manufacturer brand products (IFS 2023, p. 10 f.). It is based on the specifications of the Global Markets Program developed in 2008 (GFSI 2023a; VDOE 2020, p. 620).
The methodology of the target/actual analysis was used to work on the topic in order to be able to carry out a conformity check with regard to the requirements of IFS Global Markets Food V3 (see Appendix 3; IFS 2023). Observations, document analyses and employee surveys were carried out to obtain the most meaningful information possible. These have been recorded and evaluated within the target-performance analysis. A total of 65 deviations (equivalent to 53.7%) were identified at the basic level, and 60 deviations (equivalent to 82.2%) at the intermediate level. These were either processed as directly implemented corrective actions or formulated as recommendations for continuous improvement in the form of an action plan (see Appendix 15). The presentation of the action plan shows the deviations, the resulting measures, the associated responsibilities, the time period with the starting point and end point of the measures, and the current status. In addition a subdivision into "Basic" and "+Intermediate" was made for a better overview in the subsequent processing by the brewery.
A review as well as assessment of relevant requirements with regard to processes and significant violations after completion of the new building and commissioning at the Ellermühle site with regard to correlation with a potential "major" rating is recommended on the part of the operations manager or brewmaster (IFS 2023, p. 30).