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Working paper
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Extractivism and political instability in the Tunisian Gafsa mining basin
(2024-05-28)
•Im Bergbaugebiet von Gafsa in Tunesien spielte die Phosphatindustrie lange eine zentrale Rolle.
•Trotz wirtschaftlicher Bedeutung führte die Art der Ressourcenausbeutung zu sozialen Unruhen und Protesten gegen ungleiche Entwicklung.
•Die sozialen Bewegungen, insbesondere der Aufstand von 2008, spiegeln den Konflikt um Arbeitsplätze, wirtschaftliche Teilhabe und regionale Entwicklung wider.
•Die Auswirkungen dieser Unruhen zeigen, dass trotz kurzfristiger Maßnahmen das grundlegende Entwicklungsmodell im Bergbaugebiet ...
Aufsatz
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Simultaneous impact modified and chain extended glass fiber reinforced poly(lactic acid) composites: Mechanical, thermal, crystallization, and dynamic mechanical performance
(2021-02-05)
Herein, glass fiber (GF) reinforced binary, ternary, and quaternary poly(lactic acid) (PLA) composites were prepared. Toughening, and chain extension of PLA was achieved through the incorporation of impact modifier and chain extender and their concurrent effects on the spectroscopic, crystallization, mechanical, thermal, and thermomechanical properties of the composites were investigated. High mechanical properties of GF influenced the mechanical performance of the composites. However, GF alone could not restrict the ...
Aufsatz
Modification of self-reinforced composites (SRCs) via film stacking process
(2022-02-25)
This work presents the mechanical behavior of self-reinforced composites (SRCs) manufactured and modified via film stacking. For modification, interleaved films made of polypropylene (PP), a thermoplastic elastomer and a polyolefin engage were combined in different ways to induce the elastic modifier into the matrix material. The content of modifier was also varied in two ways. First, the films were produced out of a single material and second out of a compound. So, the same content of modifier was implemented in two ...
Aufsatz
Wood-Polypropylene Composites: Influence of Processing on the Particle Shape and Size in Correlation with the Mechanical Properties Using Dynamic Image Analysis
(2018-11-16)
The particle size and shape are of momentous significance for the mechanical properties of plastic composites. However, natural fillers, like wood, are not consistent in these attributes. In order to investigate the shared traits between these characteristics, WPCs were produced using polypropylene, hardwood and softwood fillers with different particle sizes and a coupling agent. Afterwards, specimens were processed using an injection molding machine. The filler sizes and shapes were measured using dynamic image ...
Aufsatz
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Characterization of wood-based multi-material systems under dynamic impact stress
(2018)
Due to its naturally grown properties, wood has played a rather subordinate role as a material for technical applications up to now. In this paper, multi-material systems based on veneers of beech (Fagus sylvatica) with different reinforcing variants were investigated. In addition to the influence of different adhesive systems (urea formaldehyde and polyurethane), the effect of reinforcing by aramid fiber fabric and stainless steel foil in different climates was examined. At the center of the investigations were ...
Aufsatz
Influences on the mechanical properties of SRCs in a combined compacting and back injecting process
(2022-03-03)
In this research paper, the effects of the combined compacting and back-injection process to produce back-injected self-reinforced composites on the mechanical properties of the self-reinforced composites (SRCs) are investigated. For this purpose, the parameters barrel temperature, time of injection and holding pressure were varied for the back injection. Tensile and bending tests were carried out on the SRCs. The results show that the mechanical properties depend to a large extent on the process parameters. The ...
Aufsatz
Cross-Linked Hydrophobic Starch Granules in Blends with PLA
(2018-04-17)
The majority of native starch is used in the food sector and in the paper industry. Only a small amount is used in polymer engineering. One reason for the reluctance of the plastics processing industry to use starch as a filling material in polymer blends is the unsatisfactory mechanical behavior of starch when combined with thermoplastics. Another reason is the hydrophilicity of starch. In order to make these materials capable of competing, an amelioration of the mechanical properties is compulsory. By means of ...
Konferenzveröffentlichung
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UV light irradiation of fibers in thermoplastic pultrusion for higher surface energy
(Society of Plastics Engineers, 2018)
Pultrusion is a common way to produce thermoplastic composites reinforced with different kinds of fibers. There are many different opportunities to improve the properties of a thermoplastic material. Different kind of fibers where pultruded in combination with different thermoplastic materials. The fiber content was set to 30wt% comparing the roving strain with the pultruded strain. UV-C light was used in the process to improve the fiber matrix adhesion. The pultruded strain was granulated and injection molded to ...
Working paper
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Institutional change in the context of a rentier economy: the Algerian case
(2024-06)
• Trotz der wirtschaftlichen Veränderungen auf globaler Ebene bleiben die institutionellen Konfigurationen des akkumulativen Rentierregimes in Algerien unverändert.
• Die Analyse dieses Rohstoffregimes macht deutlich, dass die Ursache für die Dominanz des Extraktivismus auf das Verhalten der Wirtschaftsakteure zurückgeführt werden kann.
• Jede wirtschaftliche Initiative des Staates scheint politisch von zwei wichtigen Imperativen geleitet zu werden: der Konsolidierung der Legitimität der politischen Macht und der ...
Aufsatz
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Circular bioeconomy: Actors and dynamics of knowledge co-production in Finland
(2022-09-01)
The circular bioeconomy is a highly scrutinized concept in Finland and internationally, with a high degree of polarization regarding forest utilization rates and distrust between certain actors. This offers an interesting case for an exploratory analysis of issues associated with knowledge co-production. Knowledge co-production entails the integration of different knowledge types and collaboration across multiple societal actors with potentially conflicting viewpoints and agendas. We interviewed key organizations ...