Aujourd’hui l’électronique fait partie intégrante de nos vies. En effet, de plus en plus d’objets intègrent de l’électronique permettant de les connecter, on appelle cela l’internet des objets (IoT). Tous ces dispositifs disposent d’une connectivité sans fil, rendant ainsi indispensable l’intégration d’une ou plusieurs antennes. De plus, l’électronique devant s’adapter à des objets de plus en plus petits et flexibles embarquant de plus en plus de capteurs tout en consommant de moins en moins d’énergie, il est intéressant de se pencher sur l’étude de nouveaux matériaux pour la réalisation d’antennes devant s’adapter à ces nouvelles contraintes. Dans ce cadre, nous nous sommes attachés dans ce travail de recherche, à la conception de structures antennaires à base de métaux liquides à température ambiante dans le but de réaliser des antennes conformables de formes complexes associant l’impression 3D, des antennes reconfigurables et des structures rayonnantes ayant la capacité de capteur. Dans ce manuscrit des prototypes d’antenne comportant ces caractéristiques ont été simulés, réalisés et mesurés. / Today, electronic is an integral part of our lives. Indeed, more and more objects integrate electronics to connect each other, this is the Internet of Things (IoT). All of these wireless devices need one or more antennas. Furthermore, It’s useful to develop new materials to realize new antennas that fit with new constraints: smaller and flexible objects, more and more sensors and less and less consuming.In this context, we have focused this research on antenna structures based on metals which are liquid at room temperature to realize conformable antennas of complex shapes combining 3D printing, reconfigurable antennas and radiant structures with the ability to sensor. In this manuscript, antenna prototypes with these characteristics have been simulated, realized and measured.

<p>Soft actuators and sensors are currently used in many industrial applications due to their capability to produce an accurate response. Researchers have studied dielectric electroactive polymers (DEAPs) because these types of structures can be utilized as actuators and as sensors being able to convert electrical energy into mechanical and vice versa. However, production of this kind of structures is complex and in general involve several steps that are time consuming. Customization of these types of structures will be ideal to enhance the performance of the devices based on the specific application. 3D printing technologies have emerged as innovative manufacturing processes that could improve fabrication speed, accuracy, and consistency with low cost. This additive manufacturing technique allows for the possibility of increased device complexity with high versatility. </p> <p>This research studied the potential of 3D printing technologies to produce DEAPs, soft actuators, and flexible sensors. The study presents novel designs of these composite flexible structures, utilizing the most flexible conductive and nonconductive materials available for fused deposition modeling, achieving versatility and high performance in the produced devices. <a>Produced DEAP actuators showed an actuation and electric resistivity higher than other electroactive structures like shape memory alloys and ferroelectric polymers.</a> In addition, this research describes the electromechanical characterization of a flexible thermoplastic polyurethane, (TPU), produced by additive manufacturing, including measurement of the dielectric constant, percentage radial elongation, tensile proprieties, pre-strain effects on actuation, surface topography, and measured actuation under high voltage. DEAP actuators were produced with two different printing paths, concentric circles and lines, showed an area expansion of 4.73% and 5.71% respectively. These structures showed high resistance to electric fields having a voltage breakdown of 4.67 kV and 5.73 kV respectively. <a>Those results are similar to the resistant of the most used dielectric material “VHB 4910”. </a></p> <p>The produced soft pneumatic actuators were successfully 3D printed in one continuous process without support material. The structures were totally sealed without the use of any sealing material or post process. Computational simulations were made to predict the response of the designed structures under different conditions. These results were compared with experimental results finding that the theoretical model is able to predict the response of the printed actuators with an error of less than 7%. This error is satisfactorily small for modeling 3D printed structures and can be further minimized by characterization of the elastomeric material. Besides that, two different grippers were designed based on the opening and closing movements of single bellows actuators. The functionality of both designs was simulated and tested, finding that both designs are capable lifting a heavier rigid structure. </p> <p>Finally, this study presents a computational simulation of a 3D printed flexible sensor, capable of producing an output signal based on the deformation caused by external forces. Two different sensors were designed and tested, working based on a capacitance and resistance change produced by structural deformation. Computational analysis indicate the capacitance sensor should undergo change of capacitance from 3 to 8.5 pF when is exposed to 30 kPa; and the resistance sensor should experience an increase from 101.8 to 103 kΩ when is exposed to 30 kPa. </p>

Background: Emerging technologies enables manufacturing companies the opportunity to stay competitive and at the same time focus on increasing their sustainability impact. One such technology is additive manufacturing which has the potential to change the way manufacturing is performed and impact entire supply chains of manufacturing companies. Multiple studies have been done in the twenty-first century regarding additive manufacturing’s sustainability impact on logistics, although there is little research that focus on impact of additive manufacturing on transportation from a sustainable perspective. Purpose: The purpose of this study is to explore the impact additive manufacturing has on the sustainability of inbound transportation. Method: A qualitative research strategy was used to explore the field of study through a multiple case study method. Through two cases, raw material providers and manufacturers within the additive manufacturing industry, data was gathered using semi-structed interviews. Conclusion: Findings from this study shows that additive manufacturing may have a sustainable impact on inbound transportation from an environmental, societal, and economic perspective. Additive manufacturing is more environmentally sustainable than conventional manufacturing for the inbound transportation leg from the raw material supplier to the manufacturing company since the technology requires lower volume of raw material to be transported, it leads to a higher transport efficiency, less frequent transportation need, and requires no return transportation. In economic impact it leads to fuel savings, less frequent transportation with less material, and a reduced inventory holding. Access to remote areas together with easier and safer material handling is the societal impact from using additive manufacturing instead of conventional manufacturing.

In this project, an additive manufacturing technique called Direct Ink Writing has been used to 3D print structures from polymer solutions containing cellulose acetate. Cellulose acetate is a synthetic compound derived from plants. The intended application involves protein separation filters for medical purposes. The printing has been performed in a lab environment with focus on high resolution, with less than 10 micrometers in fibre size. Glass capillaries with an inner diameter of 3-10 micrometers were used as nozzles. Three-dimensional structures with a height of 100 micrometers and a fibre thickness of 2 micrometers were made. The results indicates that cellulose acetate is a promising polymer for Direct Ink Writing in high resolution. Improvements are needed in the ink design and/or the technical construction of the printer to avoid clogging of the nozzle.

No description available.

<p>Two longstanding goals in subsurface science are to induce fractures with a desired geometry to adaptively control the interstitial geometry of existing fractures in response to changing subsurface conditions. Many energy and water-related engineering applications that use induced fractures to withdraw and inject fluids from subsurface reservoirs occur in some sedimentary rock.  Sedimentary rock such as shales often exhibit anisotropic mechanical properties because of bedding, layering and mineral texture.  These structural and textural features also affect fracture formation and in turn the resulting fracture geometry. Understanding the interplay between the microscopic mineral fabric and structure and how it effects fracture geometry is important for the prediction of the geometry of induced fractures and to the determination of the most ideal conditions for maximizing energy production and minimizing leaks from sequestration sites in the subsurface. </p> <p><br></p> <p>This Ph.D. thesis research focuses on the formation and geometry of fractures in anisotropic rock and the identification of geophysical signatures of fracture formation using additively manufactured gypsum rock analogs. Specifically, the work is grouped into three topics: (1) material controls on fracture geometry, toughness and roughness in additively manufactured rocks; (2) acoustic emissions (AE) during fracture formation in anisotropic additively manufactured rocks; and (3) determination of the effect of fluid-filled oriented voids in fractures on compressional to shear wave conversions. </p> <p><br></p> <p>For topic (1), unconfined compressive strength (UCS), Brazilian and 3-point bending (3PB) tests under pure and mixed mode mechanical tests were performed on cast and 3D printed gypsum samples that were characterized using 3D Xray microscopy, Xray Diffraction and SEM to examine the micro-structure of the samples. Research on topic 1 discovered microstructural controls on fracture surface roughness and the failure behavior of anisotropic rock and that the failure mode (tensile, mixed mode I and II, mixed mode I and III) affects the fracture propagation path and the surface roughness which is controls to the flow paths through a fracture. The results suggest that detailed mineralogical studies of mineral texture/fabric in laboratory or core samples is important to unravel failure strength, surface roughness, and how fractures propagate in layered geological media. </p> <p><br></p> <p>For topic (2), UCS tests were performed with concurrent measurements of acoustic emissions (AE) on cylindrical specimens: cast gypsum (CG) samples, and 3D printed (3DP) samples with five different orientations of bassanite layer and gypsum texture relative to the loading direction. Mechanical properties and induced fracture surface information were compared with the collected the AE signals to study if there is a way to tell the differences between the induced fracture surfaces with the AE signals patterns together with loading data. Examination of the AE signal amplitude from post-peak loading revealed that more ductile behavior was associated with more AE events that occurred over a longer period of time, and the resultant fracture surfaces were rougher than for narrow time distributions of events. </p> <p><br></p> <p>For topic (3), a detail study of fracture void orientation was performed using ultrasonic compressional, P, and shear, S, waves to determine how energy is partitioned when P-to-S or S-to-P conversions occur for waves normally incident on an air-filled or fluid-filled fracture. In this study, experiments and computer simulations were performed to demonstrate the link among cross-coupling stiffness, micro-crack orientation and energy partitioning into P, S, and P-S/S-P wave. The cross-coupling stiffness was created by 3D printing samples with linear arrays of micro-cracks oriented at  $0^o$, $\pm15^o$, $\pm30^o$, $\pm45^o$, $\pm60^o$, $\pm75^o$, and $90^o$. For $45^o$ orientation, measurements were made on air-filled and fluid-filled (silicon oil). For the air-filled fractures, the observed energy partitioning matched the simulated behavior obtained from discontinuous Galerkin simulations. Information on local fracture geometry is contained in the far-field waves. When filled with a viscous fluid, the P- and S- waves amplitude exhibited slight increases and decreases, respectively. The P-to-S converted mode amplitude decreased 30\% with an increase in fluid viscosity from 1–300kcSt. This suggests that P-S converted mode provides a potential method to remotely probe changes in fluid viscosity in fractures. </p> <p><br></p> <p>The work from the 3 research topics demonstrated that micro-scale structure impacts macroscale behavior and signals used for monitoring the condition of a rock. Additively manufactured samples enabled the exploration and determination of (1) the impact of mineral fabric orientation in layered media on failure load, fracture propagation path, and fracture surface roughness, (2) the sensitivity of P-to-S conversions to fluid viscosity, and (3) how oriented voids within a fracture effect energy partitioning. These research findings advances our current understanding of role microscopic properties and structure on the generation, propagation and geometry of induced fractures in anisotropic rock, and help to identify the best imaging modalities to use to identify the seismic signatures of the viscosity of fluids in fractures with oriented voids. These contributions will help unravel the complex behavior often observed in natural rock that is structurally and compositionally complex with features and heterogeneity.  </p> <p><br></p>

Vocal fold models are valuable for studying voice production. They provide an alternative method of studying the mechanics of the voice that does not require in vivo experimentation or the use of excised human or animal tissue. In this thesis, a new method of creating vocal fold models through additive manufacturing is described. The purpose of this research was to reduce model fabrication time, to decrease the number of model failures during manufacturing, and to lay the foundation for creating models with more lifelike geometric and material properties. This research was conducted in four stages. First, a suitable silicone additive manufacturing technique using a UV-curable silicone was chosen. The technique chosen was called freeform reversible embedding (FRE) and involved embedding liquid silicone material into a gel-like medium named organogel. The UV-curable silicone's material properties were identified to confirm its utility in vocal fold model design. Second, an open-source, fused deposition modeling slicing software was selected to create g-code for the printer. Applicable software settings were tuned through qualitative printing tests to find their optimal values for use in FRE printing. Third, 3D-printed cubes were used in tensile tests to characterize the material properties of FRE-printed, silicone material. The cubes were found to be anisotropic, exhibiting different modulus values corresponding to the layer orientation of the printed material. Fourth, vocal fold models were FRE-printed in two different layer orientations and were used in phonation tests to gather data for onset pressure, vibratory frequency, amplitude, and flow rate. The printed models self-oscillated and withstood the strains induced by phonation. These tests showed that layer direction affects the phonation properties of the models, demonstrating that models with layers in the coronal plane had slightly lower frequencies and onset pressures than models with layers in the sagittal plane. The models' onset pressures were higher than what is found in human vocal folds. However, their frequencies were within a comparable range. These tests showed the effectiveness of additive manufacturing in the application of vocal fold fabrication, reducing production effort by allowing researchers to go directly from model design to fabrication in a single manufacturing step. It is anticipated that this method will be modified to incorporate printing of multiple stiffnesses of silicone to better mimic the material properties of vocal fold tissue, and that the anisotropy of 3D-printed material will be leveraged to model the anisotropy of human vocal folds. This work also has potential application areas outside of voice research.

I det här examensarbetet undersöks möjligheterna med framtida storskaliga 3D-skrivare i byggindustrin. Mycket händer just nu på området och vi är på väg mot en ny revolution i byggnadskonsten där robotarna och 3D-skrivarna kommer att ha en allt mer betydande roll. Arbetet undersöker i detalj hur vi skulle kunna använda oss av tekniken. En villa har fått stå modell för olika typer av experiment och redovisar olika tankar och idéer kring ämnet. / This Master Thesis project examines the opportunities with future large scale 3D-printing in the construction industry. A lot is happening with new 3D-printers and materials and we are on our way towards a revolution in the art of construction. A future world where the robots and 3D-printers will play a big role. The project examines in detail how we can use this new technique. A villa have been a model for different types of experiments and shows different thoughts and ideas around the subject.

No description available.

Indiana University-Purdue University Indianapolis (IUPUI) / Introduction: Endodontic treatment in teeth with pulp canal obliteration (PCO) is challenging. Guided Endodontic Access (GEA) combines information from a cone-beam computed tomography (CBCT) scan with an intra-oral scan to create a stent that can be used as a guide to treat teeth with PCO. GEA stents designed with traditional palatal accesses were shown to be successful in accurately negotiating these 3D printed teeth with simulated PCO, however, the difference in accuracy between the traditional palatal access compared to a conservative incisal access is not yet known. Objective: This in vitro study compares GEA stents designed with an incisal access approach to GEA stents designed with a traditional palatal access approach. The effect on the overall degree of deviation of the designed access path from the prepared path is evaluated by measuring the degree of angle of deviation and amount of deviation in millimeters. Materials and Methods: A 3-D printed maxillary model of an anonymous patient was used. PCO was simulated in a 3D printed natural #8 using the coDiagnostiX software tooth at two levels: coronal and mid-root. A GEA stent that extended from tooth #3 to tooth #14 with a guide sleeve over the simulated tooth #8 was accessed with a dedicated 1.0 mm diameter and 20 mm length drill that is designed to fit the access sleeve. 15 GEA stents had guides utilized for the incisal access approach, and 15 GEA stents had guides utilized for the traditional palatal access approach. Results: Angle, mesio-distal (base), and mesio-distal (tip) deviations were significantly lower for the incisal access compared to the traditional access. Inciso-apical (base) deviation was significantly more negative for incisal access compared to the traditional access. Bucco-lingual (base) deviation was significantly more negative for traditional access compared to the incisal access, while incisal and traditional accesses were not significantly different for bucco-lingual (tip) deviation. Coronal 1/3 calcification groups had significantly more mesio-distal (base) deviation than the middle 1/3 and no PCO groups. The no PCO group had significantly more negative inciso--apical (base) deviation than the coronal 1/3 calcification and middle 1/3 calcification groups, and the coronal 1/3 calcification group was significantly more negative than the middle 1/3 calcification group. The coronal 1/3 calcification group had significantly more mesio-distal (tip) deviation than the no PCO group. PCO level did not have a significant effect on angle, bucco-lingual (base), or bucco-lingual (tip) deviations. Conclusion: The utilization GEA via incisal access resulted in less degree and amount of drill deviation compared to the traditional access at all levels of calcification, however, the level of PCO did not influence the degree and amount of drill deviation between the incisal and traditional access approaches. It can be concluded that the use of a GEA stent that utilizes an incisal access approach in teeth with PCO will result in a more predictable outcome.