Dysphagia is a serious eating disorder currently affecting around 100 thousand people in Sweden and it’s estimated that 1 in 10 people will develop some form of dysphagia during their lifetime around the world. The condition occurs mainly in elders and people who’ve suffered a stroke. The disorder prohibits proper swallowing of food, impairing the ability to close airways and let food enter the proper pathways. Patients with dysphagia have to eat grounded food in order to not suffer from malnutrition. The food is usually served in timbales which are sometimes decorated but might not look as appealing or realistic as one might think. The repetitive and unrealistic food creates further appetite loss which may lead to malnutrition. This is the case amongst many elderly in home care and the complications maybe very serious indeed, leading to organ dysfunction, hospitalization and eventually death. The current timbales made at the kitchens for elderly care in Helsingborg are punched with a tool in rectangular, circular shapes and often decorated. A solution would be to increase the aesthetics of the served timbales and make them realistically looking. 3D printing offers numerous new opportunities for food production and may very well set a standard in the future for producing aesthetically pleasing food. Silicone molds may also provide the same, if not better results at the time being at a fraction of the price, sufficing to revert any negative impacts of the current timbale appearance. In the hopes of proving both concepts the work will initially be focused on preparing a broccoli but also applying one of the concepts on a cinnamon bun providing additional application. This report presents the progress of designing a realistic 3D broccoli model, product development of a realistic broccoli food mold, 3D scanning, 3D food printing and a literature study. The designed model could not be printed due to the printing gel’s incapability of supporting complex structures. Instead master shapes created for shaping the food mold were scanned, sliced and printed. The same masters were used as means for a second food mold. Both food molds did manage to cast realistic shapes with a broccoli puré and of a soft gelatine suspension. Material alternatives were evaluated as well as manufacturing possibilities. The designed broccoli and a refined scanned broccoli were both offered for free as means for further research and development.

<div>Additively manufactured (AM) metals have been increasingly fabricated for structural applications. However, a major hurdle preventing their extensive application is lack of understanding of their mechanical properties. To address this issue, the objective of this research is to develop a computational model to simulate the creep behavior of nickel alloy 718 manufactured using the laser powder bed fusion (L-PBF) additive manufacturing process. A finite element (FE) model with a subroutine is created for simulating the creep mechanism for 3D printed nickel alloy 718 components.</div><div><br></div><div>A continuum damage mechanics (CDM) approach is employed by implementing a user defined subroutine formulated to accurately capture the creep mechanisms. Using a calibration code, the material constants are determined. The secondary creep and damage constants are derived using the parameter fitting on the experimental data found in literature. The developed FE model is capable to predict the creep deformation, damage evolution, and creep-rupture life. Creep damage and rupture is simulated as defined by the CDM theory.</div><div>The predicted results from the CDM model compare well with experimental data, which are collected from literature for L-PBF manufactured nickel alloy 718 of creep deformation and creep rupture, at different levels of temperature and stress. </div><div><br></div><div>Using the multi-regime Liu-Murakami (L-M) and Kachanov-Rabotnov (K-R) isotropic creep damage formulation, creep deformation and rupture tests of both the secondary and tertiary creep behaviors are modeled.</div><div>A single element FE model is used to validate the model constants. The model shows good agreement with the traditionally wrought manufactured 316 stainless steel and nickel alloy 718 experimental data collected from the literature. Moreover, a full-scale axisymmetric FE model is used to simulate the creep test and the capacity of the model to predict necking, creep damage, and creep-rupture life for L-PBF manufactured nickel alloy 718. The model predictions are then compared to the experimental creep data, with satisfactory agreement.</div><div><br></div><div>In summary, the model developed in this work can reliably predict the creep behavior for 3D printed metals under uniaxial tensile and high temperature conditions.</div>

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This work investigates the feasibility of producing small scale, low aerodynamic loading wind tunnel models, using FDM 3D printing methods, that are both structurally and aerodynamically representative in the wind tunnel. To verify the applicability of this approach, a 2.07% scale model of the NASA CRM was produced, whose wings were manufacturing using a Finite Deposition Modeling 3D printer. Experimental data was compared to numerical simulations to determine percent difference in wake distribution and wingtip deflection for multiple configurations. Numerical simulation data taken in the form of CFD and FEA was used to validate data taken in the wind tunnel experiments. The experiment utilized a wake rake to measure 3 different spanwise locations of the wing for aerodynamic data, and a videogrammetry method was used to measure the deflection of the wingtips for structural data. Both numerical simulations and experiments were evaluated at Reynolds numbers of 258,000 and 362,000 at 0 degrees angle of attack, and 258,000 at 5 degrees angle of attack. Results indicate that the wing wake minimum in the wind tunnel test had shifted approximately 8.8mm at the wingtip for the Nylon 910 wing at 258,000 Reynolds number for 0 degrees angle of attack when compared to CFD. Videogrammetry results indicate that the wing deflected 5.9mm, and has an 18.6% difference from observed deflection in FEA. This reveals the potential for small scale wind tunnel models to be more representative of true flight behavior for low loading scenarios.

Yes / Three-dimensional printing (3DP) has demonstrated great potential for multi-material fabrication because of its capability for printing bespoke and spatially separated material conformations. Such a concept could revolutionise the pharmaceutical industry, enabling the production of personalised, multi-layered drug products on demand. Here, we developed a novel stereolithographic (SLA) 3D printing method that, for the first time, can be used to fabricate multi-layer constructs (polypills) with variable drug content and/or shape. Using this technique, six drugs, including paracetamol, cffeine, naproxen, chloramphenicol, prednisolone and aspirin, were printed with dfferent geometries and material compositions. Drug distribution was visualised using Raman microscopy, which showed that whilst separate layers were successfully printed, several of the drugs diffused across the layers depending on their amorphous or crystalline phase. The printed constructs demonstrated excellent physical properties and the different material inclusions enabled distinct drug release profiles of the six actives within dissolution tests. For the first time, this paper demonstrates the feasibility of SLA printing as an innovative platform for multi-drug therapy production, facilitating a new era of personalised polypills.

With the rise of high frequency communication systems such as 5G, new types of antennas has to be developed in order to meet the new requirements. In recent years, lens antennas made of periodic structures has been shown to have desirable performance when increasing operational frequency without increasing the size of the antennas. One way of manufacturing the lenses for the antennas are with 3D printers loaded with dielectrics with specified permittivity. This project group studied the process of designing and manufacturing a flat Maxwell fish eye lens at 5 GHz with a bandwidth of 3.5 GHz to 6 GHz. The resulting design is a lens based on a periodic configuration of cuboid unit cells made from dielectrics which consisted of a hole. By choosing the ratio of dielectric and holes in the unit cells, each part of the lens could be tuned to achieve a specific effective refractive index required for realising the Maxwell fish eye lens.

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The concept of plasma flow control is a relatively new idea based on using atmospheric plasma placed near the edge of an air foil to reduce boundary layer losses. As with any new concept, it is important to be able to quantify theoretical assumptions with known experimental results for validation. Currently there are a variety of experiments being done to better understand plasma flow control, but one particular experiment is through the use of multi-physics modeling of dielectric barrier discharge actuators. The research in this thesis uses optical measurement techniques to validate computational models of flow control actuators being done concurrently at Virginia Tech. The primary focus of this work is to design, build and test plasma actuators in order to determine the plasma characteristics relating to electron temperatures and densities. Using optical measurement techniques such as plasma spectroscopy, measured electron temperatures and densities to compare with theoretical calculations of plasma flow control under a variety of flow conditions. This thesis covers a background of plasma physics, optical measurement techniques, and the designing of the plasma actuator setups used in measuring atmospheric plasmas. / Master of Science

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