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Asta Nurmela

Bio: Asta Nurmela is an academic researcher from VTT Technical Research Centre of Finland. The author has contributed to research in topics: Creep & Superalloy. The author has an hindex of 3, co-authored 9 publications receiving 227 citations.

Papers
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TL;DR: In this article, the applicability of extrusion-based 3D printing technology for food pastes made of protein, starch and fiber-rich materials was assessed, as a starting point in the development of healthy, customized snack products.

355 citations

Journal ArticleDOI
TL;DR: In this article, new creep models have been established for predicting creep strain and rupture of 316L and316L(N), using the Wilshire equations and logistic creep strain modelling for improved accuracy.

20 citations

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TL;DR: In this article, the authors studied the properties of thermoplastic cellulose-based composites and their properties using injection molding and 3D printing of granules, aiming to maximize the cellulose content in composites.
Abstract: The increasing environmental awareness is driving towards novel sustainable high-performance materials applicable for future manufacturing technologies like additive manufacturing (AM). Cellulose is abundantly available renewable and sustainable raw material. This work focused on studying the properties of thermoplastic cellulose-based composites and their properties using injection molding and 3D printing of granules. The aim was to maximize the cellulose content in composites. Different compounds were prepared using cellulose acetate propionate (CAP) and commercial cellulose acetate propionate with plasticizer (CP) as polymer matrices, microcellulose (mc) and novel cellulose-ester additives; cellulose octanoate (C8) and cellulose palmitate (C16). The performance of compounds was compared to a commercial poly(lactic acid)-based cellulose fiber containing composite. As a result, CP-based compounds had tensile and Charpy impact strength properties comparable to commercial reference, but lower modulus. CP-compounds showed glass transition temperature (Tg) over 58% and heat distortion temperature (HDT) 12% higher compared to reference. CAP with C16 had HDT 82.1 °C. All the compounds were 3D printable using granular printing, but CAP compounds had challenges with printed layer adhesion. This study shows the potential to tailor thermoplastic cellulose-based composite materials, although more research is needed before obtaining all-cellulose 3D printable composite material with high-performance.

7 citations

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TL;DR: The first successful application of the high precision pneumatic loading system for advanced material testing was developed at VTT in 1995 as mentioned in this paper, which is capable of operating in a range of extreme conditions such as high temperature, pressurised water or steam, Super Critical Water (SCW) and irradiation environments.

3 citations


Cited by
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Journal ArticleDOI
TL;DR: In this article, a gel model system composed of carrageenan-xanthan-starch was prepared for an extrusion-based 3D food printer, and the 3D printing process was divided into three stages and the corresponding rheological properties of inks for each stage were determined, namely extrusion stage (yield stress, viscosity and shear-thinning behaviour), recovery stage (shear recovery and temperature recovery properties) and self-supporting stage (complex modulus G* and yield stress at room temperature).

256 citations

Journal ArticleDOI
TL;DR: A good overview of existing additive manufacturing techniques can be found in this paper, with more focus on the extrusion-based technologies (fused deposition modeling and direct ink writing) due to their scalability, cost efficiency and wider range of material processability.

233 citations

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TL;DR: This paper reviews the state-of-the-art in terms of 3D printing technology using natural-derived feedstocks, including lignocellulose, starch, algae, and chitosan-based biopolymers, and proposes a strategical development roadmap with identified material property requirements, key challenges, as well as possible solutions.

231 citations

Journal ArticleDOI
TL;DR: The benefits and limitations of 3D food printing were critically reviewed from a different perspective while providing ample mechanisms to overcome those barriers.
Abstract: Background Digitalizing food using 3-Dimensional (3D) printing is an incipient sector that has a great potential of producing customized food with complex geometries, tailored texture and nutritional content. Yet, its application is still limited and the process utility is under the investigation of many researchers. Scope and approach The main objective of this review was to analyze and compare published articles pertaining 3D food printing to ensure how to reach compatibility between the huge varieties of food ingredients and their corresponding best printing parameters. Different from previously published reviews in the same journal by Lipton et al. (2015) and Liu et al. (2017), this review focuses in depth on optimizing extrusion based food printing which supports the widest array of food and maintains numerous shapes and textures. The benefits and limitations of 3D food printing were critically reviewed from a different perspective while providing ample mechanisms to overcome those barriers. Key findings and conclusions Four main obstacles hamper the printing process: ordinance and guidelines, food shelf life, ingredients restrictions and post processing. Unity and integrity between material properties and process parameters is the key for a best end product. For each group, specific criteria should be monitored: rheological, textural, physiochemical and sensorial properties of the material its self in accordance with the process parameters of nozzle diameter, nozzle height, printing speeds and temperature of printing. It is hoped that this paper will unlock further research on investigating a wider range of food printing ingredients and their influence on customer acceptability.

230 citations