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The increased use cases for laser powder bed fusion (LPBF) in the research and commercial domains necessitate a better understanding of the inputs and the processing parameters. Porosity in parts manufactured by LPBF could lead to premature failure and increased cost. The powder bed, which is selectively laser melted, must be as densely packed as possible to ensure high-density parts. This paper aims to identify and qualify the variables that affect the packing density of the powder bed.

Six different independent variables that affect the packing density of the powder were identified and quantified. The chemical composition, true powder density, powder size distribution, powder circularity and convexity and powder morphology were studied. A powder bed density capsule was printed in place to determine the actual powder bed density in the LPBF unit.

Particle size destitution is the most critical aspect of the packing density in the LPBF unit. Powder with better circularity, convexity and higher powder density has proven to pack less densely than powder with many smaller particles. A more significant number of fine particles will ensure the voids between larger particles are filled, and a denser item, with less porosity, can be manufactured.

The independent variables quantified in this study to determine their effect on the packing densities are discussed. Adherence to the ASTM standard applicable to this industry is discussed, and the quantification method is evaluated. This work’s original contribution is identifying the effect of the ratio of D₉₀ to D₁₀ values based on particle diameter and its interaction within the LPBF unit to result in the highest possible packing density.

Many end users turn to Google Books and social tagging services to identify books of interest. How successful they are will depend on subject indexing applied in these services (among other factors). The study aimed to determine: (1) to what degree are Queerlit books identified as LGBTQ+ books in widely used information services, in particular Google Books, LibraryThing and Goodreads; and, (2) whether metadata in these information services could be considered of value for the Queerlit database and complement its highly extensive and highly specific indexing.

The study compared keywords (subject index terms, tags) assigned to works of Swedish LGBTQ+ fiction across three commercial services: Google Books, Goodreads and LibraryThing, against the curated database, Queerlit.

Of the 1320 LGBTQ+ works in Queerlit, only a small portion was found in the three web services: 8.26% on Google Books (n = 109), 13.26% on Goodreads (n = 175), while about half on LibraryThing (55.3%, n = 730). This underrepresentation of Swedish LGBTQ+ works in the three international commercial information services makes them hardly of value to the readers. This is exacerbated by the fact that only a minority of Queerlit books found in the three services are categorised as LGBTQ+. The Queerlit database might benefit from consulting social tagging services when indexing both LGBTQ+ specific and general themes.

No earlier study compared in a systematic manner four different information retrieval systems and identified challenges as well as potential benefits in relation to finding LGBTQ+ fiction.