<p dir="ltr">The production of aluminum components by laser powder bed fusion additive manufacturing (LPBF-AM) offers simultaneous weight reduction benefits through low material density and topology optimization. The primary limitation of the method – hot cracking in high-strength compositions – is addressed by the reactive additive manufacturing (RAM) process, which introduces ceramic-forming metallic particles to powder feedstock. <i>In situ</i> reactions subsequently inoculate equiaxed grains, prevent cracking, and strengthen the resulting alloy. The adoption of RAM alloys in aerospace applications requires the elimination of heterogeneous defects, requiring an understanding of laser processing effects and feedstock quality. To meet these needs, the collected work presents characterization methods based on x-ray tomography, seeking to establish novel descriptors for RAM feedstock and microstructures.</p><p dir="ltr">In the first two chapters, x-ray microscopy (XRM) is applied to produce multi-dimensional particle measurements for feedstock powder qualification. Evolving existing measure-and-classify processes, a method is described to characterize AA7050-RAM2 feedstock that is rapid, interpretable, and descriptive of the highly deformed particles observed. Applying the developed methodology to an analysis of recycled AA7050-RAM2 rationalizes decreasing particle sizes by identifying the selective removal of specific shape classes. Combined with quantitative electron microscopy of particle microstructures, sieving and heat effects are comprehensively reported, demonstrating a modernized powder analysis workflow.</p><p dir="ltr">In the second two chapters, the characteristic reactions seen in LPBF of AA7050-RAM2 are characterized. Correlative SEM/EDS and nanoindentation identified reactive phases and their mechanical properties and found a correlation between the extent of the Al-Ti reaction and the degree of particle remelting. Using 3D XRM measurements, the populations and distributions of low- and high-reaction particles were quantified, raising questions regarding homogenization mechanisms in laser-processed, particle-reinforced alloys. Thus, thin wall samples were produced and characterized to visualize convective and thermal history effects within symmetrical tracks. Novel observed mechanisms include thermal grain coarsening, keyhole-induced convection, and pore segregation by size. The accumulated microstructural quantification and novel perspective on pore movement provide a basis to improve contouring processes in RAM alloys and to better align fluid dynamics models of printing with experimental data.</p>

Liquid microdroplet resonators provide an excellent tool for optical studies due to their innate smoothness and high quality factors, but they can be difficult to control. By using 3D printed mounts to support the droplets, we can obtain precise control over the droplet geometries and positions. We here present our work with oil, water, and ice microdroplets, as well as tools required to enable their study. We first present methods for creating 3D printed mounts for oil microdroplet resonators. The mounts enable precise positioning of the droplets relative to a tapered optical fiber. The oil microdroplet resonators exhibited quality factors of over 4 × 10^5. Water microdroplet resonators are more difficult to create due to the evaporation of water. By supporting the droplet on a 3D printed structure that supplies water to the droplet, we can maintain a water microdroplet resonator in an ambient environment while also controlling its shape and size. The resulting resonators have high quality factors, with values measured as high as 6 × 10^8. Ice microdroplets may be useful as optical resonators; however, typically ice appears cloudy due to trapped air bubbles. We present a method for freezing clear ice microdroplets in both humid and dry environments, enabling the formation of a clear ice droplet without the risk of additional crystal growth. To facilitate the freezing of droplets in a low-humidity environment, we have developed an environmental control chamber capable of maintaining an arbitrary humidity level and controlling the temperature of a small sample. We here present instructions for its manufacture as well as validation of its function. Finally, we present an automated fabrication system for the creation of tapered and dimpled optical fibers. Tapered fibers have been essential in our work as tools for optical coupling to microdroplet resonators, and dimpled fibers allow for coupling to on-chip structures. The system we present allows for their fabrication with no user input and is able to produce fibers with efficiencies over 90% at a high yield.

Additive manufacturing (AM), also known as 3D-printing, has gained widespread adoption across various industries owing to advancements in manufacturing methods and printers. This technology offers users creative freedom, diverse manufacturing methods, and a wide range of material options. Consequently, many industries, including defense, are keen on integrating AM into their production processes. In the defense sector, AM facilitates rapid prototyping and the efficient blending of different materials, unlocking new possibilities that conventional methods cannot achieve. The ability to fabricate intricate geometries is another pivotal aspect driving the preference for AM. Thus, this study aims to explore the potential of lattice structures to impart unique material properties applicable in defense applications. Specifically, the investigation focuses on understanding the impact of discharge directions and lattice structures on radar properties for Material X. Analysis revealed that while discharge direction exhibited minimal influence on radar properties, different lattice structures could modify these properties by altering parameters such as unit cell size and panel thickness. Keywords: Additive manufacturing, 3D printing, lattice structures, discharge direction, radar properties, defense industry

The importance of the aura, the metaphysical element that gives art, artifacts, and other objects of cultural heritage their authenticity, has been heavily contemplated ever since the publication of Walter Benjamin's "The Work of Art in the Age of Mechanical Reproduction." This thesis strives to add to this conversation and expand upon it by delving into the emergence of additive manufacturing, or what is more commonly known as 3D printing, and its relation to museums and other institutions that comprise the public humanities. This technology challenges the auratic properties of an exhibit by first digitizing it onto a computer by scanning it and then uploading this data to a 3D printer, which then proceeds to replicate the scanned exhibit down to incredibly fine details. For museums the possibility that 3D printed replicas, increasingly able to be indistinguishable from the original and capable of being produced in great numbers at ease, replacing their auratic exhibits is a very real possibility to consider. This thesis argues that some museums are responding by despatializing their exhibitions in order to uphold their auratic exhibits, while others are offsetting the potential loss by turning their exhibitions into tactile, multisensory experiences. Either option, which are not mutually exclusive, transforms the traditional museum. This thesis ultimately concludes that it's possible to reconcile the auratic exhibit with the 3D printed replica should these institutions properly adapt. Doing so will allow them to continue fulfilling their mission statements to preserve and promote the auratic exhibits well into the future. / Master of Arts / The emergence of 3D printing in recent years has brought with it many implications for not just society, but also the museums and other institutions that comprise the public humanities. Along with printing out objects designed entirely within a computer, 3D imaging and printing technology can easily process scanned objects that have been digitized onto a computer and then reproduce that object while accurately mimicking the specific features that once made it unique. As they increasingly improve in their ability to print with more and more materials, distinguishing the original from its copies from sight alone brings with it an existential dilemma for museums that rely on the authenticity of the original to draw visitors. If everyone could potentially have their own life-size copy of David thanks to a 3D printer, what fate awaits the original David? This thesis will detail this possible development and how exhibitions are responding. Arguing that some museums are in fact utilizing 3D printers outside the halls of their institutions in order to uphold their original collections, while others are offsetting the potential loss by embracing the reproducibility 3D printers provide to allow visitors to touch and interact with 3D printed copies in multisensory exhibitions. Either option, which are not mutually exclusive, transforms the traditional museum going experience. This thesis ultimately concludes that it’s possible to reconcile the original with a perfectly mimicked copy should these institutions properly adapt, allowing them to fulfill their missions to preserve and promote the originals well into the future.

Yes / Three-dimensional printing (3DP) has the potential to cause a paradigm shift in the manufacture of pharmaceuticals, enabling personalised medicines to be produced on-demand. To facilitate integration into healthcare, non-destructive characterisation techniques are required to ensure final product quality. Here, the use of process analytical technologies (PAT), including near infrared spectroscopy (NIR) and Raman confocal microscopy, were evaluated on paracetamol-loaded 3D printed cylindrical tablets composed of an acrylic polymer (Eudragit L100-55). Using a portable NIR spectrometer, a calibration model was developed, which predicted successfully drug concentration across the range of 4–40% w/w. The model demonstrated excellent linearity (R2 = 0.996) and accuracy (RMSEP = 0.63%) and results were confirmed with conventional HPLC analysis. The model maintained high accuracy for tablets of a different geometry (torus shapes), a different formulation type (oral films) and when the polymer was changed from acrylic to cellulosic (hypromellose, HPMC). Raman confocal microscopy showed a homogenous drug distribution, with paracetamol predominantly present in the amorphous form as a solid dispersion. Overall, this article is the first to report the use of a rapid ‘point-and-shoot’ approach as a non-destructive quality control method, supporting the integration of 3DP for medicine production into clinical practice. / Open Access funded by Engineering and Physical Sciences Research Council United Kingdom (EPSRC), UK for their financial support (EP/L01646X).

Yes / Composites have clinical application for their ability to mimic the hierarchical structure of human tissues. In tissue engineering applications the use of degradable biopolymer matrices reinforced by bioactive ceramics is seen as a viable process to increase osteoconductivity and accelerate tissue regeneration, and technologies such as additive manufacturing provide the design freedom needed to create patient-specific implants with complex shapes and controlled porous structures. In this study a medical grade poly(l-lactide) (PLLA) was used as matrix while apatite-wollastonite (AW) was used as reinforcement (5 wt% loading). Premade rods of composite were pelletized and processed to create a filament with an average diameter of 1.6 mm, using a twin-screw extruder. The resultant filament was 3D printed into three types of porous woodpile samples: PLLA, PLLA reinforced with AW particles, and PLLA with short AW fibres. None of the samples degraded in phosphate buffered solution over a period of 8 weeks, and an average effective modulus of 0.8 GPa, 1 GPa and 1.5 GPa was obtained for the polymer, particle and fibre composites, respectively. Composite samples immersed in simulated body fluid exhibited bioactivity, producing a surface apatite layer. Furthermore, cell viability and differentiation were demonstrated for human mesenchymal stromal cells for all sample types, with mineralisation detected solely for biocomposites. It is concluded that both composites have potential for use in critical size bone defects, with the AW fibre composite showing greater levels of ion release, stimulating more rapid cell proliferation and greater levels of mineralisation. / The research was funded in part by the UK EPSRC Centre for Doctoral Training in Additive Manufacturing and 3D Printing (EP/L01534X/1), the UK EPSRC Centre for Innovative Manufacture in Medical Devices (EP/K029592/1), and Glass Technology Services Ltd., Sheffield, UK.

The first edition of a series holds value. It is a bookmark that holds a place in time that the artist can look back to and see the progress that led up to that point, as well as the continued progress that's been made after. Designing and creating a set of characters, bringing the main character through 3D modeling, and printing it has multiple uses in the industry. The techniques learned through this process have been used in toy design, stop-motion animation, museums, and medical applications. 3D printing is advancing and providing an opportunity to create high-definition models that can be reproduced quickly while maintaining their initial integrity. This paper will go through the model's design concept and how to execute it. It is also a culmination of all the traditional skills acquired from a fine art background combined with all the new skills learned in the digital media field. This project aims to create a cohesive set of 2D character concepts centered around the story By Command of the Prince Daniel (Nikolaevich, 1915). The main antagonist, Baba Yaga, was then brought through the 3D modeling process so she could be resin printed and turned into a collectible figurine. Descriptive character traits from her stories were reimagined while providing a unique approach to the design that still preserves the story's essence.

Preview image from Ariel Adam's Baba Yaga: Character Design and Collectible Figurine. / https://dc.etsu.edu/digitalmedia-culminating-experience-gallery/1000/thumbnail.jpg

Introduction: Integrating 3-dimensional (3D) printing with lipid-based formulation (LBF) is impacting pediatric pharmaceutical manufacturing by enabling personalized oral dosage forms tailored to children's specific needs. Serious challenges are created by manipulating conventional adult dosages to produce suitable dosages for the pediatric population. The study explores an emulsion gel with two model lipophilic drugs, Aprepitant and Irbesartan, using semi-solid extrusion (SSE) as a 3D printing method to produce patient-centered dosages. Method: The solubility of the two model drugs in the studied LBF type IIIA – MC was determined using the shake-flask method combined with High-Performance Liquid Chromatography with Ultraviolet Detection (HPLC-UV) analysis. Once determined, LBF was loaded with 90% of the soluble drug amount to later produce the emulsion by mixing the drug-loaded LBF with Milli-Q water. The emulsion gel was produced as the next step by adding three different polymers to the emulsion. The three polymers were Methylcellulose Methocel (A4C), Methylcellulose Methocel (A4M), and Sodium Crosscarmellose (AcDiSol). Lastly, tablets were 3D-printed using a BIO X 3D printer with a pneumatic printhead. The tablets were vacuum-dried and analyzed for mass and content uniformity, and disintegration time.  Results: The thermodynamic solubility of Aprepitant in LBF IIIA – MC was determined to be 11.30 mg/g while the solubility of Irbesartan was 4.08 mg/g. The produced tablets contained lower concentrations of the drugs compared to the traditional dosages available on the market. The 3D-printed tablets passed the European Pharmacopeia requirements for mass and content uniformity, and disintegration time.  Conclusion: The study showed justified results indicating the emulsion gel can be used to produce tablets loaded with different poorly water-soluble drugs. All characterization studies done on the 3D-printed tablets carried out according to the European Pharmacopeia guidelines showed correct mass and content uniformity together with reasonable disintegration time. This suggests that the emulsion gel has the potential to be used to produce tablets loaded with any other lipophilic drug, potentially multiple drugs loaded at the same time.

Additive manufacturing (AM) is a rapidly developing manufacturing method utilized in fields such as the aerospace industry. In-space AM is a technology of interest for the future of spaceflight, including on-orbit manufacturing. However, AM materials are subject to defects that may impact their performance in space-based applications. How these defects change the material’s reaction to the space environment, specifically atomic oxygen (AO), has only recently been explored. AO is a highly corrosive, dominant constituent in low Earth orbit that causes continuous erosion of spacecraft surfaces. The effect of AO on various AM materials is investigated in this thesis. Stainless steel, aluminum, ULTEM™, and titanium samples made using differing AM techniques were exposed to 24 hours of AO in order to calculate material susceptibility in the form of erosion yield. Additionally, reflectance spectra were collected to detect changes in material at the surface. Over 24 hours, samples were exposed to an average fluence of 9.10 × 1020 atoms cm−2, equating to about 200 times the naturally occurring AO flux at International Space Station altitudes. The statistical significance of effects from AO exposure were determined. Comparisons were drawn between the AM materials tested and conventionally manufactured materials. It was found that mass loss due to AO erosion was significant for ULTEM™, powder bed fusion titanium, and directed energy deposition titanium. The ULTEM™ tested in this thesis had significantly higher erosion yield when compared to ULTEM™ tested by NASA, while all other material comparisons had insufficient evidence to draw similar conclusions. Reflectance spectra did not reveal unexpected differences before and after exposure.