Kunal Masania

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Masania

First Name

Kunal

ORCID

0000-0001-9498-1505

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Publications 1 - 10 of 31

3D Printed Scaffolds for Monolithic Aerogel Photocatalysts with Complex Geometries
Schreck, Murielle; Kleger, Nicole; Matter, Fabian; et al. (2021)
Small
Monolithic aerogels composed of crystalline nanoparticles enable photocatalysis in three dimensions, but they suffer from low mechanical stability and it is difficult to produce them with complex geometries. Here, an approach to control the geometry of the photocatalysts to optimize their photocatalytic performance by introducing carefully designed 3D printed polymeric scaffolds into the aerogel monoliths is reported. This allows to systematically study and improve fundamental parameters in gas phase photocatalysis, such as the gas flow through and the ultraviolet light penetration into the aerogel and to customize its geometric shape to a continuous gas flow reactor. Using photocatalytic methanol reforming as a model reaction, it is shown that the optimization of these parameters leads to an increase of the hydrogen production rate by a factor of three from 400 to 1200 µmol g−1 h−1. The rigid scaffolds also enhance the mechanical stability of the aerogels, lowering the number of rejects during synthesis and facilitating handling during operation. The combination of nanoparticle-based aerogels with 3D printed polymeric scaffolds opens up new opportunities to tailor the geometry of the photocatalysts for the photocatalytic reaction and for the reactor to maximize overall performance without necessarily changing the material composition.
Experimental characterisation of textile compaction response: A benchmark exercise
Yong, Ana X.H.; Aktas, Alper; May, D.; et al. (2021)
Composites Part A: Applied Science and Manufacturing
This paper reports the results of an international benchmark exercise on the measurement of fibre bed compaction behaviour. The aim was to identify aspects of the test method critical to obtain reliable results and to arrive at a recommended test procedure for fibre bed compaction measurements. A glass fibre 2/2 twill weave and a biaxial (±45°) glass fibre non-crimp fabric (NCF) were tested in dry and wet conditions. All participants used the same testing procedure but were allowed to use the testing frame, the fixture and sample geometry of their choice. The results showed a large scatter in the maximum compaction stress between participants at the given target thickness, with coefficients of variation ranging from 38% to 58%. Statistical analysis of data indicated that wetting of the specimen significantly affected the scatter in results for the woven fabric, but not for the NCF. This is related to the fibre mobility in the architectures in both fabrics. As isolating the effect of other test parameters on the results was not possible, no statistically significant effect of other test parameters could be proven. The high sensitivity of the recorded compaction pressure near the minimum specimen thickness to changes in specimen thickness suggests that small uncertainties in thickness can result in large variations in the maximum value of the compaction stress. Hence, it is suspected that the thickness measurement technique used may have an effect on the scatter. © 2020 Elsevier Ltd.
Effect of fabric architecture, compaction and permeability on through thickness thermoplastic melt impregnation
Studer, Julia; Dransfeld, Clemens; Cano, Jon J.; et al. (2019)
Composites Part A: Applied Science and Manufacturing
3D Printed Liquid Crystal Polymer Thermosiphon for Heat Transfer under Vacuum
Seshadri, Bharath; Hischier, Illias; Masania, Kunal; et al. (2023)
Advanced Materials Technologies
A novel approach is presented to 3D print vacuum-tight polymer components using liquid crystal polymers (LCPs). Vacuum-tight components are essential for gas storage and passive heat transfer, but traditional polymer 3D printing methods often suffer from poor interfaces between layers and high free volume, compromising vacuum integrity. By harnessing the unique properties of LCPs, including low free volume and low melt viscosity, highly ordered domains are achieved through nematic alignment of polymer chains. Critical gas-barrier properties are demonstrated, even in thin, single-print line-walled samples ranging from 0.8 to 1.6 mm. A 200 mm evacuated thermosiphon is successfully printed, which exhibits a thermal resistance of up to 2.18 K/W and an effective thermal conductivity of up to 28 W/mK at 60 degrees C. These values represent a significant increase compared to the base LCP material. Furthermore, the geometric freedom, enabled by 3D printing through the fabrication of complex-shaped thermosiphons, is showcased. The authors study highlights the potential of LCPs as high-performance materials for 3D printing vacuum-tight components with intricate geometries, opening new avenues for functional design. An application of integrating 3D printed thermosiphons as selective heat transfer components in building envelopes is presented, contributing to greenhouse gas emissions mitigation in the construction sector.
Light-Based Printing of Leachable Salt Molds for Facile Shaping of Complex Structures
Kleger, Nicole; Fehlmann, Simona; Lee, Seunghun S.; et al. (2022)
Advanced Materials
3D printing is a powerful manufacturing technology for shaping materials into complex structures. While the palette of printable materials continues to expand, the rheological and chemical requisites for printing are not always easy to fulfill. Here, a universal manufacturing platform is reported for shaping materials into intricate geometries without the need for their printability, but instead using light-based printed salt structures as leachable molds. The salt structures are printed using photocurable resins loaded with NaCl particles. The printing, debinding, and sintering steps involved in the process are systematically investigated to identify ink formulations enabling the preparation of crack-free salt templates. The experiments reveal that the formation of a load-bearing network of salt particles is essential to prevent cracking of the mold during the process. By infiltrating the sintered salt molds and leaching the template in water, complex-shaped architectures are created from diverse compositions such as biomedical silicone, chocolate, light metals, degradable elastomers, and fiber composites, thus demonstrating the universal, cost-effective, and sustainable nature of this new manufacturing platform.
Three-Dimensionally Printed Hierarchal Sand Structures for Space Heating Applications
Seshadri, Bharath; Shammas, Demetris; Hischier, Illias; et al. (2024)
3D Printing and Additive Manufacturing
In addition to the well-documented resource efficiency and geometrical freedom, Digital Fabrication (DFAB) revolutionizes architecture by integrating functionalities into building elements, unlocking untapped potential from the micro- to the macroscales. This study uses binder-jet printed sand for a DFAB prototype-Fireplace2-tailored for indoor heating. Named after its traditional counterpart, Fireplace2 showcases DFAB's prowess in crafting precise microclimates for heightened thermal comfort. Our research, tuning mechanical and thermal properties across micro and meso scales, illustrates DFAB's utility in architects' hands for crafting tailored microclimates. This approach manipulates the effective thermal conductivity and macroscale topology for stability against toppling (0.8 kN). A vertical infill porosity gradient establishes a surface temperature gradient, countering ventilation-induced thermal gradients. With a minimal operational temperature vertical gradient (+0.2 degrees C), complying with international comfort standards (Predicted Mean Vote -0.23, People Dissatisfied 6%), Fireplace2 stands testament to DFAB's microclimate-shaping capabilities despite challenges like foot-level ventilation. The study propels DFAB into a sustainable paradigm, aligning occupant comfort with environmental consciousness, thereby fostering more efficient and enjoyable indoor spaces.
Flow and heat transfer during compression resin transfer moulding of highly reactive epoxies
Keller, Andre; Dransfeld, Clemens; Masania, Kunal (2018)
Composites Part B: Engineering
Multimaterial Volumetric Printing of Silica-Based Glasses
Barbera, Lorenzo; Madrid-Wolff, Jorge; Emma, Roberto; et al. (2024)
Advanced Materials Technologies
Silicate glasses have played a major role as structural and functional materials in human civilization since ancient Egypt. Despite their widespread use and importance in modern society, silica glasses with complex geometries are only fabricated in automated processes using 3D printing. Here, the volumetric printing of silica-based glasses with tunable multimaterial and microstructural control is reported. Volumetric printing enables complex shaping of photo-reactive resins in a few seconds using illumination techniques analogous to those employed for medical imaging. Particle-filled and phase-separating resins are used as photo-reactive feedstock that is quickly printed in 3D and subsequently converted into silica glasses through conventional heat treatment. Using rheology and imaging techniques, it is shown that the design of the resin is crucial to print complex geometries with high shape fidelity. The capabilities of the printing platform are demonstrated by fabricating a silica-based filtration device combining dense and porous glass with tunable compositions in a unique 3D structure.
3D Printing of Salt as a Template for Magnesium with Structured Porosity
Kleger, Nicole; Cihova, Martina; Masania, Kunal; et al. (2019)
Advanced Materials
Quantifying the role of mineral bridges on the fracture resistance of nacre-like composites
Grossman, Madeleine; Bouville, Florian; Masania, Kunal; et al. (2018)
Proceedings of the National Academy of Sciences of the United States of America

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Kunal Masania

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