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Shockwaves are mechanical pressure pulses generated in liquids and gases. Based on the principles of acoustics, shockwavescan propagate through fluids such as water. At interfaces of materials with different acoustic impedances, mechanical energy is dissipated, and disintegration of biological tissue can be achieved. Physical properties as well as technical requirements for shockwave generation by electrohydraulic, electromagnetic or piezoelectric energy conversion have been reported in the literature. The use of electrohydraulic shockwaves for food treatment is an emerging food processing technology, where a lack of scientific and technical knowledge has limited further advancements in process and equipment design. In scientific literature, single aspects required for process description are available, e.g., in metallurgy, mining, air purification or particle accelerators, but their combination toward a combined model is required to characterize underlying mechanisms of action. In food, most of the studies have focused on shockwave technology for treatment of meat cuts with the purpose of reducing aging time, softening of tissue and improving its tenderness. Other applications of the shockwave technology could expand to biological inactivation, targeted texture modifications and improving extractive and refining processes in agriculture industries. Total processing costs are estimated in a range of a few Euros per ton of product. Despite being a promising alternative to existing processes used for these purposes, the application of shockwave in the food industry is limited to date to research on pilot-scale prototypes.
This chapter presents the mechanism of the enhancement of freezing by means of ultrasound (US). It has been demonstrated that the effects of US are a rather complex issue. In theory, ultrasound creates cavitation bubbles throughout the volume of the product, which promotes nucleation of the ice and crushes the crystals already present in food. They can also enhance convective heat transfer to the cooling media, thereby accelerating freezing. Moreover, it has been shown that ultrasound reduces the degree of supercooling before nucleation in frozen food. Additionally, numerous experimental studies indicate that ultrasound assisted freezing is a good method to achieve homogenous crystallizations, reduce the deteriorating effect of freezing on food, and thus improve quality after thawing.
Der Text behandelt die Bedeutung nachhaltiger Ernährung und die Herausforderungen bei der Integration von Nachhaltigkeitsaspekten in die berufliche Bildung, insbesondere in den Korn-handhabenden Berufen. Tägliche Ernährungsentscheidungen werden als maßgeblich für Umwelt, Gesellschaft und Gesundheit hervorgehoben. Die EAT-Lancet-Kommission schlägt eine Planetarische Gesundheitsdiät vor, die klimafreundlich und gesund ist. Die Förderung von Nachhaltigkeitskompetenzen in der beruflichen Bildung wird als Schlüssel für langfristige Veränderungen in Betrieben betont. Der Modellversuch Korn-Scout zielt darauf ab, Lehr-/Lernmaterialien zu entwickeln, die die Nachhaltigkeitsorientierung von Auszubildenden in Korn-handhabenden Berufen fördern. Dieser besteht aus vier Elementen: Status-quo-Analyse, Entwicklung von Lehr-/Lernmaterialien, Erprobung und Transfer in die Praxis. Kommunikation wird als Schlüsselfaktor für die systematische Integration von Bildung für nachhaltige Entwicklung in die Ausbildung betont. Die Evaluation der Materialien während der Covid-19-Pandemie führte zu sinnvollen Optimierungsvorschlägen.Erunterstreicht die Bedeutung von Kommunikationskompetenzen für nachhaltiges Handeln in den Korn-handhabenden Berufen. Effektive Kommunikation entlang der Wertschöpfungskette ist entscheidend, um Nachhaltigkeitsaspekte von der landwirtschaftlichen Produktion bis zum Verzehr zu integrieren. Neben der Kommunikationskompetenz werden auch andere Fähigkeiten wie die Suche, Verarbeitung und Integration von nachhaltigkeitsrelevanten Informationen betont. Der Modellversuch Korn-Scout identifizierte berufsübergreifende Nachhaltigkeitskompetenzen entlang der Korn-Food-Supply-Chain, wobei einige Berufe spezifische Kompetenzen aufweisen. Die systematische Weiterentwicklung dieser Kompetenzen ist entscheidend für die strukturelle Integration von Nachhaltigkeit in der beruflichen Praxis. Lehr-/Lernmaterialien aus dem Modellversuch werden durch Zusammenarbeit mit Praxispartnern in die Praxis übertragen. Der Ausblick betont die Notwendigkeit weiterer Projekte und Anpassungen in den Ausbildungsordnungen für eine umfassende Verankerung von Nachhaltigkeit in der beruflichen Ausbildung.
Dieses Kapitel behandelt Marktforschungsansätze zur Wirkungsanalyse unternehmerischer Nachhaltigkeitshandlungen auf Endverbrauchermärkten. Ziel ist ein Überblick über Methoden, die aufgrund moderater Budgetvoraussetzungen in KMU und der angewandten Wissenschaft eingesetzt werden können. Dabei werden Herausforderungen der Messung ökologischer, sozialer und ethischer Kaufeigenschaften besonders berücksichtigt.
Wasser
(2021)
The mineralization of soil organic nitrogen (N) and crop residues can significantly contribute to the N supply of vegetable crops. However, short-term mineralization dynamics are difficult to predict. On the other hand, fast-growing crops like spinach are highly sensitive to N shortage. Therefore, in situ soil columns have been tested to estimate the actual N supply via mineralization in field-grown spinach. In ten fertilization trials covered soil columns (20 cm in diameter) were driven into the soil to a depth of 30 cm at the start of the cultivation. Eight columns were repeated in three blocks within a total trial area of 0.10 to 0.25 ha. Net N mineralization was derived by subtracting the soil mineral N concentration (Nmin) in the upper 30 cm before installation from the concentration inside the columns at harvest. For comparison, a balance sheet was calculated for spinach plots receiving no N fertilization (zero plots) as well as fertilized plots and used as a proxy for net N mineralization. In this approach the initial Nmin concentration in the upper 30 cm of the soil, the N supply via irrigation, and fertilization as well as the total aboveground N uptake by spinach and the Nmin residue were considered. By using soil columns, N mineralization was determined with a mean coefficient of variation of 18%. A higher spatial variability of up to 43% was observed when spinach was grown as a second crop. The average net N mineralization rate ranged between 2 kg ha‑1 week‑1 (0-30 cm) in winter-grown spinach and 3-7 kg ha‑1 week‑1 (0-30 cm) in the other seasons. Nitrogen mineralization measured by the soil columns was qualitatively confirmed with the data obtained by the balance sheet. Soil columns enable repeated samplings during the spinach cultivation. In this way, top dressing rates can be adjusted to the actual N supply.
Spinach is a nitrogen (N)-demanding crop characterized by a shallow root architecture. Especially in the first weeks after sowing, significant N uptake is limited to the uppermost few centimetres of the soil. However, base fertilization is usually based on the soil mineral N (Nmin) concentration in the upper 30 cm. Therefore, the objective of this study was to examine whether the soil sample depth for calculating the base N fertilization can be reduced to the 0-15 cm layer. In seven field trials, conducted during spring, summer and autumn seasons, either a low or high base fertilization dose was applied at sowing. Until top dressing, soil samples were frequently taken in the upper 0-15 and 15-30 cm layers to determine the average Nmin concentration in each layer. Top dressing was applied when the first true leaves had unfurled. With this fertilizer application, the total N supply was aligned between both treatments based on the Nmin concentration in the upper 30 cm of the soil. Aboveground fresh and dry masses were determined after reaching a fresh mass yield of 15-20 t ha‑1 and related to the mean Nmin concentration in the first 3 to 4 weeks of cultivation between sowing and top dressing. It was shown that the Nmin concentration in the upper 0-15 cm of the soil highly reflects the base fertilization rate. By contrast, the Nmin concentration in the 15-30 cm layer remained unaffected. However, the Nmin concentration of both top soil layers can affect fresh and dry mass yield at harvest. Therefore, the entire 0-30 cm soil layer should be considered when calculating the base N fertilization rate in field-grown spinach. Measurements revealed that spinach fresh and dry masses were increased until the N availability of between 54 and 59 kg ha‑1 (0-30 cm) was reached at the seedlings stage, respectively.
Mobile Eye Tracking in Landscape Architecture: Discovering a New Application for Research on Site
(2018)
This chapter presents the process of establishing a laboratory for mobile eye tracking focussing
on real-world, open-space environments within the field of landscape architecture at
the Osnabrück University of Applied Sciences (D) as well as the latest results from the feasibility
study ‘Point de Vue’, which defines the basis for qualitative interaction analyses in
landscape architecture. Eye tracking is a tool that has been used extensively in the domains
of psychology, marketing, usability and user experience in remote and mobile applications,
but has rarely been used in real-world open spaces because of technical limitations. To
check the possibilities of mobile eye tracking as a new application in open spaces, several
exploratory tests and a feasibility study with long-term experiments have been carried out
in urban settings as well as in world famous parks such as ‘Grosser Garten’ in Hannover (D)
and ‘Stourhead’ in Wiltshire (GB). These experiments have shown extraordinary results that
enable us to use mobile eye tracking as a new tool in open space research to gain knowledge
about how people act, react and interact in open-space environments. Being able to see and
understand what catches one’s eye and the response to it will be a guide to better design.