Printability, microstructure, and flow dynamics of phase-separated edible 3D inks

Personalizing the nutrition and sensorial attributes of 3D printed foods primarily requires various multiscale properties to be individually tailored. Herein, multiscale inks are produced by segregative phase separation, a candidate for further 3D inks texture control, of gellan gum (GG), and whey protein isolate (WPI). The inks microstructure, rheological properties, flow dynamics, their impact on printability, and properties-variables interactions are analyzed using experimental design and clustering. The gels are a GG matrix structured with WPI beads or fibers ranging from 100??m in diameter. A straightforward, six-step printability test determines that high-quality prints require increasing viscosity, which is obtained by reducing the size and length of the WPI beads. Also, flow dynamics and rheology models predict the shear stress and extrusion force, according to the print settings and food-inks fluid properties. The phase-separated inks enable printing at high speed (>25/50?mm/s) upon low extrusion forces (<50?N) and low shear stresses (<500?Pa), according to the calculations and model validation. These printability evaluation methodologies and fabrication of phase-separated inks are particularly interesting for 3D food printing, bioprinting, or biomaterials applications.Nanotechnology-based functional solutions project, funded by ERDF and CCDR-N, under the call Norte2020 (Ref. NORTE-01-0145-FEDER-000019) and Enhance Microalgae (High added-value industrial opportunities for microalgae in the Atlantic Area), funded by ERDF, under the Call Interreg Atlantic Area 2014–2020 (Ref. EAPA_338/2016)info:eu-repo/semantics/publishedVersio

A virtual framework for simulation of complex viscoelastic flows

A framework is presented and demonstrated in which extrusion and laydown of viscoelastic fluids can be simulated. Examples include application of seam sealing and adhesive material, and additive manufacturing processes. A state of the art fluid flow solver is used to solve the flow equations and various rheological constitutive models are supported, such as shear thinning viscosity models or more complex viscoelastic stress models. With connection to robot path planning software the framework can be used in the product preparation phase to improve quality, reduce material consumption and commissioning time

Electrochemical Passivation Properties of Valve Transition Metal Carbides

Transition metal carbides have the potential to be employed as corrosion protective coating for a variety of applications such as e.g. steel based bipolar plates, porous transport layers or as catalyst support in polymer electrolyte membrane fuel cells and water electrolyzers. Yet, little is known of their fundamental, intrinsic corrosion and passivation properties. Herein, we conducted a detailed electrochemical passivation study of various valve transition metal carbides such as titanium carbide, tantalum carbide or tungsten carbide. Via flow cell measurements coupled to an inductively coupled plasma mass spectrometer, the in situ transition metal dissolution was monitored, and the faradaic dissolution efficiency was calculated. Together with the determination of the grown oxide layer via X-ray photoelectron spectroscopy, a thorough evaluation of the passivation efficiency was conducted. Moreover, it was shown that a beneficial stabilization effect can be achieved through alloying of different carbides which paves the way towards tailor-made coatings or catalyst support materials