While 3D printing technologies first appeared in the 1980s, prohibitive costs, limited materials, and the relatively small number of commercially available printers confined applications mainly to prototyping for manufacturing purposes. As technologies, printer cost, materials, and accessibility continue to improve, 3D printing has found widespread implementation in research and development in many disciplines due to ease-of-use and relatively fast design-to-object workflow. Several 3D printing techniques have been used to prepare devices such as milli- and microfluidic flow cells for analyses of cells and biomolecules as well as interfaces that enable bioanalytical measurements using cellphones. This review focuses on preparation and applications of 3D-printed bioanalytical devices.

Indiana University-Purdue University Indianapolis (IUPUI) / Extrusion-based 3D printing is one of the emerging additive manufacturing technologies used for printing a range of materials from metal to ceramics. In this process, the required material is extruded from the extruder in the form of a slurry. Zeolite and MOFs are mainly used for CO2 adsorption in the form of pellets and beads due to their good adsorptive property. Researchers are developing monoliths of Zeolite and MOFs and fabricate them using traditional extrusion and implement them in the gas adsorption applications as an option for beads and pellets by developing a monolithic structure. Previous research on Zeolite 13X and 5A have shown good structural and physical properties in monolith form. In this study, we developed slurry of two molecular sieve Zeolite 3A and 4A monoliths powders, mixing it with bentonite clay, methyl cellulose, and PVA as a binder. The slurry preparation was carried out at room temperature. Once the 3D printed samples are dried at room temperature, a sintering process was performed to increase mechanical strength. To be used in real-time applications, the 3D printed Zeolite sample need to have sufficient mechanical strength. The BET surface area test showed good results for Zeolite 13X compared to available literature. The surface area calculated for 3D printed Zeolite 13X was 767m2/g and available literature showed 498 m2/g for 3D printed Zeolite 13X. The microhardness values of 3D printed Zeolite samples were measured using a Vicker hardness tester. The hardness value of the 3D - printed Zeolite samples increased from 8.3 ± 2 to 12.5 ± 3 HV0.05 for Zeolite 13X, 3.3 ± 1 to 7.3 ± 1 HV0.05 for Zeolite 3A, 4.3 ± 2 to 7.5 ± 2 HV0.05 for Zeolite 4A, 7.4 ± 1 to 14.0 ± 0.5 HV0.05 for Zeolite 5A respectively. The SEM, EDS and XRD analysis was performed for 3D printed samples before and after sintering to evaluate their structural properties. The SEM analysis reveals that all 3D printed Zeolite samples retained their microstructure after slurry preparation and also after the sintering process. The porous nature of 3D printed Zeolite walls was retained after the sintering process. The EDS analysis showed that the composition of 3D printed Zeolite samples remained somewhat similar with minor variation for before and after sintering. The framework structure of Zeolite Type X for Zeolite 13X and Zeolite Type A for Zeolite 3A, 4A, 5A were in good shape after sintering as standard peak intensity points were retained. Zn-MOF74 was synthesized using solvothermal synthesis which is a well-established synthesis process used for the synthesis of MOFs. We also developed slurry for Zn-MOF-74 using bentonite clay and PVA as binders and printed small parts using hand printing.

Melt granulation is a versatile process that is underutilized in the pharmaceutical industry. Most pharmaceutical wet granulation and twin-screw extruders can be adapted for melt granulation. Twin-screw melt granulation (TSMG) is of interest since is a continuous process and allows for flexible process design and a high degree of control. TSMG can be used to produce formulations for oral immediate or sustained release. This research focuses on the use of TSMG to taste-mask APIs. Many APIs are bitter or unpleasant tasting. Taste-masking may be required, particularly for products intended for pediatric patients. Taste-masking has been achieved with many different techniques, but a simple, cost-effective method that can be applied to many different APIs is not currently available. A matrix encapsulation approach using continuous twin-screw melt granulation was attempted with three different APIs. The resulting granule properties, particularly particle size, are related to the granulation process parameters. Prediction of taste-masking based on in vitro assessments is challenging and generally clinical evaluation is required. A small-volume dissolution method was developed as a screening test the melt granules. It is not clear if this technique is predictive of clinical taste-masking performance, but it is expected to be an improvement over discrete sampling or typical quality control dissolution methods. The dissolution rate was estimated using the Noyes-Whitney equation and correlated to the mean granule particle size. From this, a simple model for time to a taste threshold could be used to define a design space around the granulation process. / Pharmaceutical Sciences

Laboratory-scale extrusion facilitated a parametric study of the metal extrusion process under controlled conditions. Hot extrusion experiments were performed on billets of both aluminum Al1100 as well as, magnesium alloys AZ61 and AM30. Tests were designed and executed with the purpose of recording load and temperature data to validate full-scale thermo-mechanical simulations performed with the commercial code HyperXtrude. Various aspects of flat die and conical die extrusion were observed, studied and modeled with the code. Conventional sine hyperbolic inverse material model was used in the simulations due to present limitations of HyperXtrude. Although this model showed a perfect viscoplastic response at constant temperature and strain rate, by proper changes in the material parameters the model captured the stress softening response characteristic of dynamic recrystallization in magnesium alloys, as shown for the case of AZ61. A framework is also presented for designing and understanding hot extrusion experiments and simulation boundary conditions.

Granulation is an important process for industries ranging from plastics to food and pharmaceutics. In the last decades, the twin-screw extruder has been more and more studied as a continuous method for granulation. But there are many questions remaining to be answered such as the functions of kneading block and the granulation behavior in this zone, the influence of the wetting method, and also the influence of the active pharmaceutical ingredient (API) properties on the granulation process. Therefore, in this project, a series of experiments were performed based on a new technique to the granulation field named ‘screw pullout’ for understanding the granulation process within the twin-screw extruder. In order to understand the specific function of an important screw element known as a kneading block, the physical particle motion reflecting progress of granulation was monitored along the screw. Different feed rate and formulations were studied; the residence time and pressure in kneading block were measured; and the granules along the screw were characterized for their porosity and size distribution. It was found that granule consolidation and breakup within the kneading block allowed the production of granules with consistent properties and excellent mechanical strength. However, the changes produced by a kneading block are dependent upon the formulation. For example, the kneading block demonstrates no observable function with formulations containing a significant content of microcrystalline cellulose. The most notable benefit of the kneading block to all tested materials appeared to be distribution of the interstitial binding liquid rather than to compact the powders. A new wetting method using a foam binder has been studied intensively in this work to assess its influence on the granulation process. A series of studies have been performed to compare the granule development along the screws as powder formulation and screw design were varied to test for the differences induced by the two wetting methods (foam delivery or liquid injection). The evolution of the granules along the screw was characterized by analyzing the particles size distribution, porosity, and fracture strength. It was found that the wetting method had minor impact on the particle size distribution due to the strong mechanical dispersion inherent to the extruder. The major finding for the pharmaceutical industry was that the foam method reduces the required amount of liquid to granulate, thereby dropping drying time after the process. The foamed binder was also found to be preferred when the formulation contains powder components with poor spreading properties. Finally, the influence of an API’s physical properties on granulation was studied by comparing formulations with varying API hydrophobicity. It was found that the API and binder distribution was not affected by the hydrophilicity of API, while the particle size distribution, porosity and fracture strength were strongly dependent on the properties of the API. / Thesis / Master of Applied Science (MASc)

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Oats are considered to be a highly nutritious breakfast food available to consumers. Heightened consumer interest in functional food products and advances in human nutrition have led to increased levels of interest in the development of new oat based products (Webster and Wood 2011). Developments in technology have led to manufacturing of instant oatmeal, making the product more convenient to consumers. Low moisture extrusion processing is one of the most widely used methods to produce ready to eat breakfast cereals; however, there has been little research carried out to determine if high moisture extrusion methods would be viable. This study evaluated the economic and technical feasibility to utilize high moisture extrusion processing to produce ready to eat oatmeal. A process economics evaluation included measuring the capital requirements to implement the system, process costing to estimate the weighted average unit cost, and net present value of high moisture extrusion production. The capital expense was significantly high. However, the unit cost is comparable to similar products in the market. The net present value of implementing the technology revealed a significant profit over the course of 20 years. Six different technical experiments were performed using a twin screw extruder, each experiment testing for the effect of different extrusion variables on finished product texture. Reference texture data was measured using a control product currently made in the industry using an alternative batch process. The processing parameters which seemed to have the biggest influence on product quality were high rates of water injection, low feed rate, high reaction zone temperature, reduction of particle size, and the use of functional ingredients in the formula. Technical hurdles such as low dwell times, steam plugging, and inconsistent feeding prevented complete starch gelatinization and the steady state of extrusion. Overall, the high moisture methodology did not yield product quality that was consistent and cannot be recommended for use.

<p>The field of superplasticity is reviewed, with particular reference to the mode of deformation and viability for industrial application. Superplastic and conventional Zn-Al eutectoid alloys are compared with regard to the pressures and time required and the problems associated with the production of shaped hollow components from billet material, using extrusion followed by pressure forming. A possible industrial process is suggested and economically assessed in a Supplement to the Dissertation. </p> / Thesis / Master of Engineering (ME)