Solar 3D printing of lunar regolith

Volcanic ashes are pyroclastic materials commonly found in many regions of the world. Many deposits of volcanic ashes are unexploited, despite their potential interest for several engineering applications. The mineralogy and chemical composition of volcanic ashes depend on the type of magma from which they originate. The two common pyroclastic materials of interest for engineering applications are scoria and pumice. These pyroclastic materials are rich natural aluminosilicate geo-resources and their valorization can be of environmental and economic benefit. The current review summarizes the main interesting research outcomes on volcanic ashes in the fields of cements and concretes, geopolymers, ceramics, low grade refractory materials, lunar soil simulants and adsorbents. Factors affecting their suitability for specific applications are screened and possible areas of interest for future research suggested.

Review on the use of volcanic ashes for engineering applications

Effects of cellulose, hemicellulose, and lignin on the morphology and mechanical properties of metakaolin-based geopolymer

Purpose: The aim of this paper is to evaluate existing scenarios for 3D Printing in order to identify the “white space” where future opportunities have not been proposed or developed to date. Based around aspects of order penetration points, geographical scope and type of manufacturing, these gaps are identified. Design/methodology/approach: A structured literature review has been carried out on both academic and trade publications. As of the end of May 2016, this identified 128 relevant articles containing 201 future scenarios. Coding these against aspects of existing manufacturing and supply chain theory has led to the development of a framework for identify “white space” in existing thinking. Findings: The coding shows that existing future scenarios are particularly concentrated on job shop applications and pull based supply chain processes, although there are fewer constraints on geographical scope. Five distinct areas of “white space” are proposed, reflecting various opportunities for future 3DP supply chain development. Research limitations: Being a structured literature review, there are potentially articles not identified through the search criteria used. The nature of the findings is also dependent upon the coding criteria selected. However, these are theoretically derived and reflect important aspect of strategic supply chain management. Practical implications: Practitioners may wish to explore the development of business models within the “white space” areas. Originality/value: Currently, existing future 3DP scenarios are scattered over a wide, multi-disciplinary literature base. By providing a consolidated view of these scenarios, it is possible to identify gaps in current thinking. These gaps are multidisciplinary in nature and represent opportunities for both academics and practitioners to exploit.

/pdf/3d-printing-the-future-scenarios-for-supply-chains-reviewed-36047k7wbw.pdf

3D printing the future: scenarios for supply chains reviewed

Extraterrestrial construction materials

Evaluation of lunar regolith geopolymer binder as a radioactive shielding material for space exploration applications

Preparation of lunar regolith based geopolymer cement under heat and vacuum

We test the standard model for the length contraction of a bundle of strings under twist, and find deviation that is significantly greater than typically appreciated and that has a different nature at medium and large twist angles. By including volume conservation, we achieve better fits to data for single-, double-, and triple-stranded bundles of nylon monofilament as an ideal test case. This gives a well-defined procedure for extracting an effective twist radius that characterizes contraction behavior. While our approach accounts for the observed faster-than-expected contraction up to medium twist angles, we also find that the contraction is nevertheless slower than expected at large twist angles for both nylon monofilament bundles and several other string types. The size of this effect varies with the individual-string braid structure and with the number of strings in the bundle. We speculate that it may be related to elastic deformation within the material. However, our first modeling attempt does not fully capture the observed behavior.

/pdf/twist-and-measure-characterizing-the-effective-radius-of-3d20gkxt.pdf

Gabrielle Davis

Papers

Evaluation of lunar regolith geopolymer binder as a radioactive shielding material for space exploration applications

Preparation of lunar regolith based geopolymer cement under heat and vacuum

Twist and measure: characterizing the effective radius of strings and bundles under twisting contraction.