abstract: The American Diabetes Association reports that diabetes costs $322 billion annually and affects 29.1 million Americans. The high out-of-pocket cost of managing diabetes can lead to noncompliance causing serious and expensive complications. There is a large market potential for a more cost-effective alternative to the current market standard of screen-printed self-monitoring blood glucose (SMBG) strips. Additive manufacturing, specifically 3D printing, is a developing field that is growing in popularity and functionality. 3D printers are now being used in a variety of applications from consumer goods to medical devices. Healthcare delivery will change as the availability of 3D printers expands into patient homes, which will create alternative and more cost-effective methods of monitoring and managing diseases, such as diabetes. 3D printing technology could transform this expensive industry. A 3D printed sensor was designed to have similar dimensions and features to the SMBG strips to comply with current manufacturing standards. To make the sensor electrically active, various conductive filaments were tested and the conductive graphene filament was determined to be the best material for the sensor. Experiments were conducted to determine the optimal print settings for printing this filament onto a mylar substrate, the industry standard. The reagents used include a mixture of a ferricyanide redox mediator and flavin adenine dinucleotide dependent glucose dehydrogenase. With these materials, each sensor only costs $0.40 to print and use. Before testing the 3D printed sensor, a suitable design, voltage range, and redox probe concentration were determined. Experiments demonstrated that this novel 3D printed sensor can accurately correlate current output to glucose concentration. It was verified that the sensor can accurately detect glucose levels from 25 mg/dL to 400 mg/dL, with an R2 correlation value as high as 0.97, which was critical as it covered hypoglycemic to hyperglycemic levels. This demonstrated that a 3D-printed sensor was created that had characteristics that are suitable for clinical use. This will allow diabetics to print their own test strips at home at a much lower cost compared to SMBG strips, which will reduce noncompliance due to the high cost of testing. In the future, this technology could be applied to additional biomarkers to measure and monitor other diseases. / Dissertation/Thesis / Masters Thesis Bioengineering 2017

<div>In this thesis, the design of the robotic cannula for minimally invasive robotic lumbar discectomy is presented. Lumbar discectomy is the surgery to remove the herniated disc material that is pressing on a nerve root or spinal cord. </div><div><br></div><div>Recently, a robotic approach to performing this procedure has been proposed that utilizes multiple teleoperated articulated instruments inserted into the surgical workspace using a single cannula. In this paper, a new robotic cannula system to work in conjunction with this new procedure is presented. It allows for the independent teleoperated control of the axial position and rotation of up to three surgical instruments at the same time. The mechanical design, modeling, controller design, and the performance of the prototype of the new system are presented in this paper demonstrating a fully functioning device for this application. A novel worm gear and rack system allow for the instrument translation while and embedded gear trains produce the rotational movement. Steady-state errors of less than 10 microns for translation and less than 0.5 degree for rotation motion are achieved in position tracking; steady-state errors of less than 100 micron per second of translation and less than 0.5 degree per second for rotation motion are obtained in speed tracking. </div>

This thesis presents a novel method of modulating silicon photonic circuits using 3D printed microfluidic devices. The fluids that pass through the microfluidic device interact directly with the silicon waveguides. This method changes the refractive index of the waveguide cladding, thus changing the effective index of the system. Through using this technique we demonstrate the shift in resonant wavelength by a full free spectral range (FSR) by increasing the concentration of the salt water in the microfluidic device from 0% to 10%. On a 60 μm microring resonator, this equals a resonant wavelength shift of 1.514 nm when the index of the cladding changes by 0.017 refractive index units (RIU), or at a rate of 89.05 nm/RIU. These results are confirmed by simulations that use both analytical and numerical methods. This thesis also outlines the development of a process that uses two-photon absorption(TPA) in silicon to produce a photoelectrochemical (PEC) etching effect. TPA induces free carriers in silicon that then interact with the Hydroflouric Acid (HF) solution that the wafer is submerged in. This interaction removes silicon away from the wafer, which is the etching observed in our experiments. Non-line-of-sight PEC etching is demonstrated. The optical assemblies used in these experiments are presented, as are several of the results of the etching experiments.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第21765号 / 工博第4582号 / 新制||工||1714(附属図書館) / 京都大学大学院工学研究科材料工学専攻 / (主査)教授 河合 潤, 教授 神野 郁夫, 准教授 奥田 浩司 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

Additively manufactured fuels are becoming more common in the area of hybrid rockets due to the enhanced possibilities provided by computer aided design and improved additive material technology. When integrated with a highly compliant yet energetic paraffin wax, the additive manufactured material can help support the paraffin wax during the burn, and improve overall performance. This study investigates thin-walled acrylonitrile butadiene styrene structures that separate paraffin wax into azimuthally partitioned cells. The fuel grains are tested using a vertical test stand, custom nitrous system, and data acquisition system. The computer program Chemical Equilibrium with Applications is used to compare common hybrid fuels such as sorbitol, polybutadiene acrylic acid acrylonitrile, and poly(methyl methacrylate) along with the manufactured fuel. The experimental results indicate the promise of higher performance using paraffin. The analyses, however, show that refinements in grain design are necessary to fully realize the advantages of paraffin.

The development of 5G and 6G entails new demandson antennas. This includes fast and reliable connections to a largenumber of devices. A wider area of coverage, and thus moreantennas are also expected, which is problematic for the expensiveantennas used today. To meet those demands, a geodesic lensantenna has been proposed. The antenna utilises several feedingports for beam forming. It is designed to operate at a frequencyof 8 to 12 GHz and is optimised to have an even coverage in thefar-field. The design is modulated with one fold to reduce theheight of the antenna. A prototype of the antenna is 3D printedwith PLA and coated with aluminium tape. The design has asimulated realised gain of 13.5 dBi and beam width of around30°. The 3D printed antenna could not be tested due to technicalproblems with the testing facilities, but is expected to have similarresults. / Med utvecklingen av 5G och 6G kommer stora krav på antenner. Flera enheter skall kunna vara uppkopplade och samtidigt krävs högre hastigheter med stabil uppkoppling. Utöver det ställs det även krav på en bred täckning vilket innebär att fler antenner behöver kopplas upp, vilka har höga kostnader idag. För att möta dessa krav har en design för en geodetisk linsantenn lagts fram. Antennen använder flera ingångar för att skapa en riktbar stråle. Den är designad för att operera inom frekvenserna 8 till 12 GHz och är optimerad för att få en jämn täckning i fjärrfältet. Designen nyttjar en vikning för att minska antennens höjd. En prototyp av antennen tillverkas med hjälp av 3D printad plast som beläggs med aluminiumtejp. Designen har en simulerad förstärking av 13.5 dBi och en strålbredd runt 30°. Den 3D printade antennen kunde inte testas på grund av tekniska problem med testutrustningen men förväntas ha liknande resultat som den simulerade. / Kandidatexjobb i elektroteknik 2022, KTH, Stockholm

Microfluidics is a continually growing field covering a wide range of applications, such as cellular analysis, biomarker quantification, and drug discovery; but in spite of this, the field of microfluidics remains predominately academic. New materials are pivotal in providing tailored properties to improve device integration and decrease prototype turnaround times. In biosensing, nonspecific adsorption in microfluidic systems can deplete target molecules in solution and prevent analytes, especially those at low concentrations, from reaching the detector. Polyethylene glycol diacrylate (PEGDA) mixed with photoinitiator forms, on exposure to ultraviolet (UV) radiation, a polymer with inherent resistance to nonspecific adsorption. Optimization of the polymerized PEGDA (poly-PEGDA) formula imbues this material with some of the same properties, including optical clarity, water stability, and low background fluorescence, that makes polydimethylsiloxane (PDMS) a widely used material for microfluidics. Poly-PEGDA demonstrates less nonspecific adsorption than PDMS over a range of concentrations of flowing fluorescently tagged bovine serum albumin solutions, and poly-PEGDA has greater resistance to permeation by small hydrophobic molecules than PDMS. Poly-PEGDA also exhibits long-term (hour scale) resistance to nonspecific adsorption compared to PDMS when exposed to a low (1 μg/mL) concentration of a model adsorptive protein. Electrophoretic separations of amino acids and proteins resulted in symmetrical peaks and theoretical plate counts as high as 4 × 105/m. Pneumatically actuated, non-elastomeric membrane valves fabricated from poly-PEGDA have been characterized for temporal response, valve closure, and long-term durability. A ∼100 ms valve opening time and a ∼20 ms closure time offer valve operation as fast as 8 Hz with potential for further improvement. Comparison of circular and rectangular valve geometries indicates that the surface area for membrane interaction in the valve region is important for valve performance. After initial fabrication, the fluid pressure required to open a closed circular valve is ∼50 kPa higher than the control pressure holding the valve closed. However, after ∼1000 actuations to reconfigure polymer chains and increase elasticity in the membrane, the fluid pressure required to open a valve becomes the same as the control pressure holding the valve closed. After these initial conditioning actuations, poly-PEGDA valves show considerable robustness with no change in effective operation after 115,000 actuations.Often, localized areas of surface functionalization are desired in biosensing, necessitating site-specific derivatization. Integration of poly-PEGDA with different substrates, such as glass, silicon, or electrode-patterned materials, allows for broad application in biosensing and microfluidic devices. Deposition of 3-(trimethoxysilyl) propyl methacrylate or (3-acryloxypropyl) dimethylmethoxysilane onto these substrates makes bonding to poly-PEGDA possible under UV exposure. Primary deposition of (3-acryloxypropyl) dimethylmethoxysilane, followed by photolithographic patterning, allows for silane removal through HF surface etching in the exposed areas and subsequent deposition of 3 aminopropyldiisopropylethoxysilane on the etched regions. Fluorescent probes are used to evaluate surface attachment methods. Primary attachment via reaction of Alexa Fluor 488 TFP ester to the patterned aminosilane demonstrates excellent fluorescent signal. Initial results with glutaraldehyde were demonstrated but require more optimization before this method for secondary attachment is viable. Fabrication of 3D printed microfluidic devices with integrated membrane-based valves is performed with a low-cost, commercially available stereolithographic 3D printer and a custom PEGDA resin formulation tailored for low non-specific protein adsorption. Horizontal microfluidic channels with designed rectangular cross sectional dimensions as small as 350 µm wide and 250 µm tall are printed with 100% yield, as are cylindrical vertical microfluidic channels with 350 µm designed (210 µm actual) diameters. Valves are fabricated with a membrane consisting of a single build layer. The fluid pressure required to open a closed valve is the same as the control pressure holding the valve closed. 3D printed valves are successfully demonstrated for up to 800 actuations. Poly-PEGDA is a versatile material for microfluidic applications ranging from electrophoretic separations, valve implementation, and heterogeneous material integration. Further improvements in PEGDA resin formulation, in combination with a UV source 3D printer, will provide poly-PEGDA devices that are not only rapidly fabricated (<40 min per device), but that also include pumps and valves and are usable with a variety of detection methods, such as laser-induced fluorescence and immunoassays, for broad application in biosensing.

Current high-throughput screening (HTS) tools (i.e., single-use 96-well filter plate) are limited to the few membrane types that are sold commercially, restricting the ability to screen membrane materials for targeted applications. In this thesis, a multi-well device capable of screening any flat-sheet membrane was designed, where multiple devices can be stacked for extensive HTS (>32 experiments). Confocal imaging of a Natrix Q cross-section – a membrane type not sold in a commercial filter plate – was carried out after 24 h in contact with green fluorescent protein to visually confirm protein-membrane interactions. The static binding capacity (SBC) of bovine serum albumin (BSA) and Herring testes DNA was found for specific parameters: membrane type (Mustang Q, Sartobind Q, Natrix Q, Durapore), salt concentration (0, 50, 100 mM NaCl), and contact time (1 min, 4 h, 8 h, 24 h). Considering solution conditions, the highest BSA SBC was observed with Natrix Q at 0 M NaCl with a contact time of 24 h. The DNA and BSA SBC values for Natrix Q were the highest among the membrane types evaluated, demonstrating consistency with literature trends. These findings suggest that SBC experiments can predict promising membrane materials for scaled-up applications. Finally, the chromatography process was replicated in this multi-well device (Natrix Q), showing 50% BSA elution from the membrane. The results of this thesis confirmed this ability to accommodate any membrane adsorber, simultaneously compare different membrane materials, and extract the membrane for post-experimental analysis. This work’s significance was emphasized in its future potential to aid with membrane material selection, particularly with exploring the properties of next-generation membrane materials (e.g., 3D-printed membranes). Three future areas for optimization with this multi-well device were highlighted: biotherapeutic purification, sequencing of membrane materials within a process, and applying it as a tool to understand ion selectivity. / Thesis / Master of Applied Science (MASc) / Membranes are used in many industries, such as water treatment, environmental remediation, and biopharmaceuticals. In the biopharmaceutical industry, high-throughput screening (HTS) tools (e.g., filter plates), which allow for miniaturized experiments, are used to perform extensive experimental analysis to determine optimal solution conditions (e.g., pH) for biomolecule binding. Unfortunately, commercial filter plates are limited in customizability for HTS of membrane materials. To address these limitations, this thesis focuses on designing and validating a multi-well device capable of incorporating any membrane adsorber. Different biomolecules (proteins, DNA), solution conditions, and membrane materials were evaluated. The results of this thesis confirmed this ability to accommodate any membrane adsorber, simultaneously compare different membrane materials, and extract the membrane for post-experimental analysis. This work also discussed using this device for future rapid membrane material selection in multiple industries (e.g., biotherapeutics, ion extraction).

OBJECTIVES: The objective was to investigate the accuracy, storage stability, and mechanical properties of 3D-printed polymeric dental materials. MATERIALS AND METHODS: Three completely dentate models, two maxillary and one mandibular each with their respective die, and three implant models were designed using dental CAD software (3SHAPE DENTAL SYSTEM). A horseshoe-shaped solid base with a posterior horizontal bar was utilized. The models were printed based on the manufacturer's instructions for four weeks using six printers with the corresponding recommended resin materials: Carbon M2 (DPR10), HeyGears A2D4K (Model HP UV2.0), Stratasys J5 (MED610), Stratasys Origin One (DM200), Envision One (E-Model LightDLP), and Asiga Pro4K (VeriModel) with a standard layer thickness of 50 μm (N=72). The models were scanned after printing using Sirona inEOS X5 scanner, while the implant models were scanned using a CT scanner (GE Phoenix V|tome|x metrology edition). The full arch models were randomly assigned to three groups of storage conditions: cold environment (LT, 4 ± 1°C), hot and dry environment (HT, 50 ± 2°C), and room temperature (RT , 25 ± 2°C, serving as the control). Each group was kept under the designated conditions and scanned at 1, 2, 3, 4, and 8 weeks. The generated STL files were imported into a 3D inspection software for comparison with the original STL files. Four sets of reference points (central fossa of first premolars and central fossae of second molars) were selected to determine six distances of inter-arch segments, from which the inter-arch distance trueness and precision deviation were measured. For the second part of the study, maxillary Lucitone Digital Print denture base (DB) (N=5), maxillary Lucitone IPN 3D Premium anterior and posterior teeth (N=6), and maxillary Keystone Keysplint Soft Clear occlusal splint (N=5) were printed using two printers (Carbon M2, Asiga Max UV) with a standard layer thickness of 50 μm for denture base and teeth, and 100 μm for the occlusal splint. The tolerance threshold was set to 50 μm for Lucitone IPN and 100 μm for Lucitone DB and Keysplint Soft. In-tolerance percentage and deviation RMS were obtained and analyzed with multivariate least square mean linear regression using JMP Pro 17 (SAS, Cary, NC) to identify significant effects (α=0.05). The third part investigated the mechanical properties of Lucitone DB and IPN using 2 printers (Carbon M2, Asiga Max UV) as follows: flexural strength (N=10) using a threepoint bend test, fracture toughness (N=10), creep (N=5), Vickers hardness test (N=15), surface roughness (N=15), while Shore A hardness (N=15) and tensile strength (N=10) were performed for Keysplint Soft Clear. Data were analyzed using one-way and multivariate least square mean linear regression followed by Tukey’s HSD test using JMP Pro 17 (SAS, Cary, NC) to identify significant effects (α=0.05). RESULTS: The in-tolerance percentage varied significantly among printers, with Carbon M2 (CAB) showing the highest values. Stratasys (J5) displayed the highest accuracy in term of precision, while HeyGears A2D4K (HGS), Carbon M2 (CAB), and Stratasys (J5) exhibited the highest accuracy in term of trueness. The inter-molar segment showed the highest deviation. No significant difference was observed in in-tolerance percentage across different print weeks except for week 2 in one printer (Stratasys Origin1). CAB exhibited a higher in-tolerance percentage for the DB than Asiga Max UV (ASG), with the fitting surface having the highest in-tolerance percentage. IPN anterior teeth had a higher intolerance percentage than posterior teeth, with ASG showing a higher value than CAB. No statistically significant difference was found in the in-tolerance percentage of Keysplint Soft Clear between ASG and CAB. Resin printed using ASG demonstrated higher flexural strength, Vickers hardness, and creep, while resin printer using CAB exhibited higher fracture toughness, with no significant difference in surface roughness between the two printers. Lucitone IPN had higher flexural strength and Vickers hardness, surface roughness , and lower creep and fracture toughness than Lucitone DB. CAB Keysplint Soft had higher tensile strength than ASG, with no statistically significant difference in Shore A hardness between the two printers. CONCLUSION: Model dimension deviations were impacted by storage conditions and the specific printer utilized, with high-temperature storage exhibiting the least stability. However, no significant difference was noted between low and room temperature storage conditions. Carbon M2 exhibited the highest level of accuracy. The of 3D-printed denture bases and denture teeth varied across different printers. Conversely, no significant difference in accuracy was observed for a soft occlusal splint between two printers. Materials printed using different printers showed statistically significant different mechanical properties.

In this work, we sought to provide a deeper understanding of the energy-absorbing capabilities of cast lattice structures. These structures absorb large amounts of energy via plastic deformation, but their most attractive characteristic from a structural standpoint is the favorable energy absorption-to-weight ratio. Conventional machining techniques are not well suited for manufacturing such complex features; therefore, we combined additive manufacturing (AM) with a well-known understanding of the metalcasting process. We used AM to produce sand molds in different sizes and with additional features for various applications — these molds were then filled with molten metal. Current literature suggests that this when appropriately applied, this methodology results in complex geometries castings comparable properties to parts made with traditionally produced sand molds. We chose to study periodic lattice structures for their repeatability and subsequent ease of making predictions via computer simulations. We first produced lightweight cast metal-ceramic composite panels of 225 x 225 x 60 mm. Our AM molds included provisions to install ceramic or hard metal tiles before pouring the molten metal. The tiles were encapsulated in the final casting to yield a composite structure. The initial material selection consisted of an aluminum A356-T6 alloy matrix with silicon carbide tiles. The composite lattice structures were tested against high-velocity projectiles — 0.30 caliber armor-piercing (AP M2) and NATO 7.62 mm ball rounds. We anticipated that the metal matrix alone would not be able to defeat these threats. However, the panels did reduce the striking velocity by approximately 20%. The thickness of the ceramic tiles varied from 4 mm to 8 mm at 2 mm increments. As expected, the hard ceramic tiles proved effective at improving the penetration resistance of the composite lattice structures — the impacts on regions with 4 mm thick tiles resulted in the reduction of striking velocity up to 49%; moreover, as the thickness was increased to 8 mm, the panels defeated the projectiles. We used these results to produce and validate a finite element (FE) model capable of replicating the experimental data within 5%. This model was later used to study how the ceramic material interacts with the lattice to absorb large amounts of kinetic energy from incident projectiles. Following, we manufactured smaller versions of these panels—50 x 50 x 90 mm test specimens for uniaxial compression testing for this instance. Once again, we relied on the capabilities of the FE method to replicate the test results within 10% for peak load and maximum displacement. We utilized computer simulations to optimize the design of the lattice structure. Its energy-absorbing capabilities were improved significantly — in this case, a 30% increase in the specific internal energy (internal energy per unit mass) as the evaluating criteria. The FE model was also used to study the performance of several other truss topologies. Lastly, we used computer simulations to evaluate the feasibility of making these cast lattice structures with ferrous alloys. We chose to work with Fe30Mn4Al0.9C due to its lower density and higher toughness than other steel grades. The first challenge was the lack of thermophysical property data in the literature for this alloy system. Hence, we used the CALPHAD method to calculate all the datasets needed to perform the mold filling and solidification simulation. Several of these calculations were validated experimentally. The location and severity of porosity between the model and the casting were in good agreement. / Doctor of Philosophy / The advent of additive manufacturing (AM), commonly known as 3D printing is a group of different digital-era technologies that has facilitated the production of complex designs that are not feasible to manufacture using conventional techniques. In the realm of metallic components one such technique involves the use of a laser beam to consolidate metallic powders via a layer-by-layer deposition process. Despite its advantages, this process has unique challenges, such as limited material selection and relatively small part volume. In this work, we have employed a hybrid approach that combines the use of AM with expertise in metalcasting to produce lightweight components with complex geometries. We used 3D printed sand molds that are then filled with molten metal of different alloy systems such as aluminum and steel. At first, we incorporate hard ceramic materials to increase the performance of the final parts under ballistics testing. Our aim is to upscale the size of current designs such that these devices can be used in various applications that require high absorption of kinetic energy, and that are lightweight and easy to replace.