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Aufsatz
Structural reorientation and compaction of porous MoS₂ coatings during wear testing
(2022-04-02)
Industrial upscaling frequently results in a different coating microstructure than the laboratory prototypes presented in the literature. Here, we investigate the wear behavior of physical vapor deposited (PVD) MoS2 coatings: A dense, nanocrystalline MoS2 coating, and a porous, prismatic-textured MoS2 coating. Transmission electron microscopy (TEM) investigations before and after wear testing evidence a crystallographic reorientation towards a basal texture in both samples. A basal texture is usually desirable due ...
Aufsatz
Microstructural Constituents and Mechanical Properties of Low-Density Fe-Cr-Ni-Mn-Al-C Stainless Steels
(2022-07-23)
Metallic material concepts associated with the sustainable and efficient use of resources are currently the subject of intensive research. Al addition to steel offers advantages in view of lightweight, durability, and efficient use of high-Fe scrap from the Al industry. In the present work, Al was added to Fe-12Cr-(9,12)Ni-3Mn-0.3C-xAl (x = 0.1–6) (wt.%) stainless steels to assess its influence on microstructure and mechanical properties. According to density measurements based on Archimedes’ principle, densities ...
Aufsatz
Microcantilever Fracture Tests of α-Cr Containing NiAl Bond Coats
(2022-01-08)
MCrAlY bond coats are widely used as oxidation-resistant coatings on superalloys. The major phase is the thermally stable intermetallic β-NiAl phase. The addition of Cr increases the oxidation and corrosion resistance but leads to the formation of α-Cr precipitates. Both phases are brittle and limit the fracture toughness of these coatings. To study the influence of thermal exposure and the resulting changing chemical composition on the fracture properties, the fracture toughness of both phases is measured by notched ...
Aufsatz
Agroecological transition in Southern Benin: What challenges for more efficient vegetable farming systems?
(2022-10-18)
In Benin, agroecological intensification and agroecological transition of vegetable farming systems is an undeniable necessity for achieving the objectives of food and nutrition security while preserving natural resources, human and animal health. The present study analyses vegetable farming systems in southern Benin, to highlight bottlenecks and challenges in the process of an agroecological transition and intensification of these systems. Data were collected with questionnaires and interview guides through individual ...
Working paper
¿Transformación o persistencia del modelo extractivista? Los desafíos del gobierno de Gabriel Boric
(2022-04)
• La transición energética influye en las decisiones políticas de Chile
• Presidente Boric busca transformar el sector minero y generar neutralidad climática
• Las materias primas de Chile son importantes para la industria europea y sus tecnologías sostenibles
• Tres posibles escenarios futuros del modelo extractivista esta analizado
Konferenzveröffentlichung
Unsymmetrische Beiträge zur Momentanreserve durch Erzeugung, Verbrauch und Speicher
(Conexio-PSE GmbH, 2022)
Im Zuge der Dekarbonisierung müssen Verbundsysteme auf wiederkehrende Situationen vorbereitet werden, während derer sie vor allem aus Wechselrichtern gespeist werden. Der stabilisierende Einfluss der durch Synchrongeneratoren direkt an das Netz gekoppelten Schwungmassen auf jede Frequenzveränderung ist heute unverzichtbar. Die inhärente Sofortreaktion von Synchronmaschinen auf Spannungswinkeländerungen und Frequenzbewegungen heißt Momentanreserve. Wenn sich Verbrauch oder Erzeugung dynamisch ändern, und besonders ...
Konferenzveröffentlichung
Asymmetric Contributions to Instantaneous Reserve by Generation, Loads, and Storage
(2022)
In the course of decarbonization, interconnected systems will have to be prepared for recurring situations during which they are fed by mostly inverter-based generation. Today, the stabilizing influence of the rotating masses directly coupled to the grid via synchronous generators on every frequency change is essential. The inherent immediate reaction of synchronous generators on voltage-angle changes and frequency variations is called instantaneous reserve. During dynamic situations such as load or generation changes ...
Dissertation
A Language Ecosystem for Modeling Microservice Architecture
(2022)
The ongoing digital transformation of our economy and society poses significant challenges towards modern software systems. Application areas like Smart Cities and Industry 4.0 set high requirements on software quality attributes like scalability and reliability. At the same time, IT companies face an ever-growing demand in flexibility and continuous improvements of delivery cycles. Microservice Architecture (MSA) is a novel approach to the realization of software architectures that aims to foster their scalability, ...
Working paper
Brazilian Development at a Standstill? Perspectives and Challenges for the New Lula Government.
(2022-12)
• Brazil has a standstill development syndrome as its development path swayed from extractivism to industrialization and back to extractivism.
• The prioritization of environmental protection and indigenous rights is the most significant novelty for Lula in 2022 compared to his previous governments.
• Lula's third mandate will not be a left-wing government due to the broadness of the coalition.
• Lula aims to improve people's livelihoods and reduce poverty by promoting industrialization. Therefore, international ...
Working paper
Colombia and the Coalition of the Pacto Histórico: From Extractivism to a Productive Economy?
(2022-07)
• The new Colombian president Gustavo Petro pushes for a transition from an extractivist to a productive economy.
• He needs to address the country’s enormous inequalities to achieve long-term peace.
• Agrarian reform and tax reform are urgent and part of the government’s plan.
• Mining will continue to be a strategic economic sector and a potential source of social conflicts that can weaken the action of
the new government if a dialogue with the affected groups is not established.
• With the new commodity boom ...