Suche
Anzeige der Dokumente 221-229 von 229
Aufsatz
A Novel Thermo-Mechanical Processing Route Exploiting Abnormal Grain Growth in Heusler-Type Co–Ni–Ga Shape Memory Alloys
(2022-10-04)
Heusler-type Co–Ni–Ga shape memory alloys attracted significant scientific attention owing to excellent superelasticity in single-crystalline state. However, due to pronounced anisotropy, polycrystalline Co–Ni–Ga suffers from transformation-induced constraints at grain boundaries and, thus, premature failure upon thermo-mechanical loading. The present study reports on a novel thermo-mechanical processing route. Hot rolling followed by solution-annealing promotes abnormal grain growth, eventually leading to high-performance ...
Aufsatz
Cooling rate as a process parameter in advanced roll forming to tailor microstructure,mechanical and corrosion properties of EN AW 7075 tubes
(2022-12-14)
The effects of solution heat treatment parameters and quench media as a processing tool for tailoring microstructure, mechanical and corrosion properties in roll forming of EN AW 7075 alloy were studied. The highest yield stress and ultimate tensile strength were obtained for the specimens quenched in water, while the air-cooled specimens exhibited inferior mechanical properties. Microstructural analysis of specimens showed that except water-quenched specimens, the parts cooled/quenched in oil, in direct contact with ...
Aufsatz
Impact of Pea necrotic yellow dwarf virus (PNYDV) on nodulation, N₂ fixation and yield in faba bean (Vicia faba, L.)
(2022-08-09)
Pea necrotic yellow dwarf virus (PNYDV) is a novel nanovirus in Europe, affecting various grain legumes. The impact of PNYDV on nodulation, symbiotic N₂ fixation and yield parameters in faba bean (Vicia faba L.) was investigated at controlled conditions in the greenhouse (2017), on-farm in natural infection foci (2018, 2019) and in a small-scale field experiment (2020). In the latter, the standard variety ‘Fuego’ was compared with the variety ‘GL Sunrise’ in early and late infections. In addition, the analogous effects ...
Aufsatz
Receding-Horizon Control of Constrained Switched Systems with Neural Networks as Parametric Function Approximators
(2022-11-21)
This work studies receding-horizon control of discrete-time switched linear systems subject to polytopic constraints for the continuous states and inputs. The objective is to approximate the optimal receding-horizon control strategy for cases in which the online computation is intractable due to the necessity of solving mixed-integer quadratic programs in each discrete time instant. The proposed approach builds upon an approximated optimal finite-horizon control law in closed-loop form with guaranteed constraint ...
Aufsatz
Peanut monoculture-induced decline in fertility of Andosols in Nicaragua
(2022-08-23)
Background: Andosols are generally characterized by strong resilience to degradation and high soil fertility. This may decline during long-term peanut (Arachis hypogea) monoculture, as indicated by soil chemical and biological properties. Aims: The study investigated the monoculture-induced changes in soil chemical environment as driver for the decline in soil fertility. Methods: In this on-farm study, soils from seven sites cropped with peanut monoculture for different periods between 1 and 20 years were analyzed ...
Aufsatz
Showcasing the multifaceted aspects of agricultural transformation: The example of mountain oases in Oman
(2022-11-11)
In the Anthropocene the consequences of land-use transformation on ecosystem services are of growing concern, particularly in fragile areas of mountain agriculture that often represent high nature-value farmland. This study uses a decadal repeated survey approach to analyse the effects of modernisation on oasis systems in the Jabal Al Akhdar region of northern Oman. This rugged mountain region at the north-eastern tip of the Arabian Peninsula experiences a growing influx of regional and international tourists since ...
Aufsatz
Designing a Co-creation System for the Development of Work-process-related Learning Material in Manufacturing
(2022-01-12)
The increasing digitalization and automatization in the manufacturing industry as well as the need to learn on the job has reinforced the need for much more granular learning, which has not yet impacted the design of learning materials. In this regard, granular learning concepts require situated learning materials to support self-directed learning in the workplace in a targeted manner. Co-creation approaches offer promising opportunities to support employees in the independent design of such situated learning materials. ...
Aufsatz
Bedeutende Städte jenseits der Metropolen? Regiopolen und ihre Rolle im deutschen Städtesystem
(2022-11-10)
Regiopolen und Regiopolregionen erfahren eine bisher kaum dagewesene Aufmerksamkeit in der deutschen Raumordnungspolitik. Neben der Förderung des deutschen RegioPole-Netzwerks durch den Bund sind Regiopolen und Regiopolregionen bereits in mehreren Raumordnungsplänen ausgewiesen. Im wissenschaftlichen Diskurs werden Regiopolen hingegen kaum aufgegriffen. Das zeigt sich insbesondere daran, dass zwar mit Dimensionen wie Stadtgröße (mehr als 100.000 Einwohner) und räumlicher Lage (außerhalb der Metropolregionen) operiert ...