22 research outputs found
Recommended from our members
Enhancing the Thermal Stability of Polyamide 6 in Powder Bed Fusion via Primary and Secondary Antioxidant Incorporation
Polyamide 6 (PA6) is a thermoplastic material widely used in manufacturing for its excellent mechanical
properties, such as high strength, stiffness, and toughness. However, its suitability for powder bed fusion (PBF)
is limited due to its susceptibility to thermo-oxidative aging, resulting in material degradation and mechanical
property deterioration over time. To address this issue, the efficacy of antioxidants in increasing the aging
resistance of PA6 in PBF was investigated. Process-adapted analysis was employed using a coupled rheometer
FTIR instrument to elucidate physical and chemical changes in the material. In addition, the viscosity number of
the virgin and processed powder, the yellow index, and the part performance were evaluated. Results revealed
that the addition of primary and secondary antioxidants significantly enhanced the aging resistance of PA6 in
PBF, thereby increasing its potential as a suitable material for additive manufacturing applications.Mechanical Engineerin
Recommended from our members
Analysis of Flow Additives in Laser-Based Powder Bed Fusion of Polymers: Implications for Flow Behavior, Processing, Temperature Profile, and Part Characteristics
Powder bed fusion of polymers requires the use of flow additives to ensure adequate flowability of the
feedstock material. However, information regarding flow additives and their load is limited, as is an
understanding of their impact on processing conditions. This study investigates the flow behavior using
static and dynamic measurements under process conditions, focusing on the influence of flow additives.
Subsequently, processing studies are conducted using thermography to analyze the laser-material interaction.
The characteristics of parts produced from Polypropylene and Polyamide 12 systems are also examined. The
findings of this research enhance the understanding of the impact of flow additives on the processing conditions
of laser-based powder bed fusion of polymers, potentially leading to optimized process parameters and
improved part quality and mechanical properties.Mechanical Engineerin
Exploring phase coherence in a 2D lattice of Bose-Einstein condensates
Bose-Einstein condensates of rubidium atoms are stored in a two-dimensional
periodic dipole force potential, formed by a pair of standing wave laser
fields. The resulting potential consists of a lattice of tightly confining
tubes, each filled with a 1D quantum gas. Tunnel-coupling between neighboring
tubes is controlled by the intensity of the laser fields. By observing the
interference pattern of atoms released from more than 3000 individual lattice
tubes the phase coherence of the coupled quantum gases is studied. The lifetime
of the condensate in the lattice and the dependence of the interference pattern
on the lattice configuration are investigated.Comment: 4 pages, 6 figure
Decoherence of Bose-Einstein condensates in traps at finite temperature
The phase diffusion of the order parameter of trapped Bose-Einstein
condensates at temperatures large compared to the mean trap frequency is
determined, which gives the fundamental limit of the line-width of an atom
laser. In addition a prediction of the correlation time of the number
fluctuations in the condensate is made and related to the phase diffusion via
the fluctuation-dissipation relation.Comment: 4 pages Revtex, revised version, to appear in Phys. Rev. Letter