High-Accuracy Generalized Average Model of Dual Active Bridge Converters

This article presents a detailed procedure for deriving the generalized average model (GAM) of a dual active bridge converter. The proposed model incorporates higher orders of harmonic components to increase accuracy. Moreover, the turn ratio of the high-frequency transformer (N_t) is considered for realistic modeling, which removes the...

Additive manufacturing of functionally graded inconel 718: Effect of heat treatment and building orientation on microstructure and fatigue behaviour

This paper addresses the effect of the post-process heat treatments on the microstructure and fatigue crack growth behaviour of the functionally graded (FG) laser powder bed fusion (L-PBF) Inconel 718 (IN718) superalloy. Sets of samples were additively manufactured (AM) altering the process parameters, namely the laser power, the laser...

Monitoring Intracellular Metabolite Dynamics in Saccharomyces cerevisiae during Industrially Relevant Famine Stimuli

Carbon limitation is a common feeding strategy in bioprocesses to enable an efficient microbiological conversion of a substrate to a product. However, industrial settings inherently promote mixing insufficiencies, creating zones of famine conditions. Cells frequently traveling through such regions repeatedly experience substrate shortages and...

Effect of microstructure induced anisotropy on fatigue behaviour of functionally graded Inconel 718 fabricated by additive manufacturing

In this paper, the effect of microstructural anisotropy on the fatigue crack growth behaviour of the functionally graded Inconel 718 fabricated through laser powder bed fusion (L-PBF) is investigated. Different manufacturing parameters, including low and high laser powers, were used to produce a variety of non-graded (NG) and functionally...

Nanoelectromechanical resonators from high-T _c superconducting crystals of Bi ₂ Sr ₂ Ca ₁ Cu ₂ O<IMG ALIGN=MIDDLE ALT=-8+δ

In this report, we present nanoelectromechanical resonators fabricated with thin exfoliated crystals of a high-T _c cuprate superconductor Bi ₂ Sr ₂ Ca ₁ Cu ₂ O. The mechanical readout is performed by capacitively coupling their motion to a coplanar waveguide microwave cavity fabricated...

Comparative performance of different scale-down simulators of substrate gradients in Penicillium chrysogenum cultures: the need of a biological systems response analysis

In a 54 m³ large-scale penicillin fermentor, the cells experience substrate gradient cycles at the timescales of global mixing time about 20–40 s. Here, we used an intermittent feeding regime (IFR) and a two-compartment reactor (TCR) to mimic these substrate gradients at laboratory-scale continuous cultures. The IFR was applied to...

Computational fluid dynamics simulation of an industrial P. chrysogenum fermentation with a coupled 9-pool metabolic model: Towards rational scale-down and design optimization

We assess the effect of substrate heterogeneity on the metabolic response of P. chrysogenum in industrial bioreactors via the coupling of a 9-pool metabolic model with Euler-Lagrange CFD simulations. In this work, we outline how this coupled hydrodynamic-metabolic modeling can be utilized in 5 steps. (1) A model response study with a fixed...

Euler-Lagrange analysis towards representative down-scaling of a 22 m3 aerobic S. cerevisiae fermentation

With reaction timescales equal to or shorter than the circulation time, the ideal mixing assumption typically does not hold for large scale bioreactors. As a consequence large scale gradients in extra-cellular conditions such as the substrate concentration exist, which may significantly impact the metabolism of micro-organisms and thereby the...

Euler-Lagrange computational fluid dynamics for (bio)reactor scale down: An analysis of organism lifelines

The trajectories, referred to as lifelines, of individual microorganisms in an industrial scale fermentor under substrate limiting conditions were studied using an Euler-Lagrange computational fluid dynamics approach. The metabolic response to substrate concentration variations along these lifelines provides deep insight in the dynamic...