Design and engineering of low-cost centimeter-scale repeatable and accurate kinematic fixtures for nanomanufacturing equipment using magnetic preload and potting

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, February 2011.Cataloged from PDF version of thesis.Includes bibliographical references (p. 127-130).This paper introduces a low-cost, centimeter-scale kinematic coupling fixture for use in nanomanufacturing equipment. The fixture uses magnetic circuit design techniques to optimize the magnetic preload required to achieve repeatability on the order of 100 nanometers. The fixture achieves accuracy to within one micrometer via an adjustable interface composed of UV curing adhesive between the mating kinematic coupling components. The fixture is monitored by a micro-vision system and moved by a six-axis nanopositioner until proper alignment is achieved, at which point the fixture position is permanently set by UV light. This thesis presents design rules and insights for design of a general accurate and repeatable kinematic fixture and presents a case study of fixtures used for tool exchange on dip pen nanolithography machines. A prototype fixturing assembly was fabricated and tested for repeatability and stability in six degrees of freedom. The test results concluded that the fixture has a 1-o- 3-D translational repeatability of 87 nanometers and a 3-D stability of 344 nanometers over 48 hours. This is an order of magnitude improvement on past low-cost accurate and repeatable fixture designs. This optimized accurate and repeatable kinematic fixture will enable repeatable, accurate, quick, and elegant tool change, thus advancing the manufacturing capabilities of nanofabrication techniques.by Adrienne Watral.S.M

Advanced Instrumentation for Practical Applications of Terahertz Spectroscopy and Imaging

Dans le spectre électromagnétique, la bande des térahertz (THz) est située entre les microondes et l’infrarouge. Le système de spectroscopie térahertz dans le domaine du temps (THz-SDT) permet d’extraire directement le champ électrique multifréquentiel. Déjà, plusieurs applications avantageuses ont été trouvées pour l’imagerie et la spectroscopie THz, et ce dans divers domaines. Cependant, malgré le potentiel que recèle les THz, plusieurs défis doivent être relevés pour faciliter sa généralisation. Dans cette thèse, nous suggérons des solutions nouvelles à deux problèmes et nous présentons une implémentation d’un système d’imagerie THz 3D, connu sous le nom de tomographie assistée par ordinateur. Premièrement, la manipulation du faisceau THz est difficile. Afin de remédier à cela, nous explorons deux types de guides d’onde en mousse : la mousse de polystyrène et la mousse de soie. La mousse de polystyrène est utilisée comme gaine pour le guide d’onde THz à deux fils métalliques. Nous montrons que les pertes additionnelles dues à la gaine de mousse sont négligeables par rapport à l’avantage d’avoir une encapsulation robuste et hermétique du guide d’onde. Pour la mousse de soie, nous montrons que les pertes sont un ordre de grandeur inférieures à celles de la soie solide. La mousse de soie a l’avantage d’être biocompatible pour des applications biomédicales ou agroalimentaires. Deuxièmement, l’acquisition de l’impulsion THz prend beaucoup de temps. La composante la plus lente dans un système THz-SDT est la ligne à délai optique. Nous implémentons une ligne à délai rotative qui est capable de réduire significativement le temps d’acquisition total. De plus, nous présentons des applications nouvelles pour les THz. Ces applications étaient auparavant impossibles en raison, justement, du long temps d’acquisition. Spécifiquement,nous observons, en temps réel, les processus d’évaporation de liquides transparents, l’application et le séchage de la peinture aérosol opaque, ainsi que la détection et l’évaluation de l’épaisseur d’objets mobiles. Troisièmement, nous implémentons un système d’imagerie THz 3D de tomographie assistée par ordinateur. Le système THz-SDT permet d’imager sur plusieurs fréquences et d’extraire l’indice de réfraction complexe d’un échantillon. Cependant, lors de l’implémentation d’un système d’imagerie THz 3D de tomographie assistée par ordinateur, plusieurs défis s’imposent,le principal étant le long temps d’acquisition. Ici, nous présentons un début d’implémentation d’un tel système. Nous discutons de plusieurs problèmes et nous présentons des solutions pour certains.----------Abstract In the electromagnetic spectrum, the terahertz (THz) frequency band is located between the microwave and the infrared. The pulsed THz time-domain spectroscopy (THz-TDS) system allows direct access to the THz electric field and its multifrequency nature. Already, THz imaging and spectroscopy have been applied to many different fields. Despite all the interest and potential, there a still some hurdles impeding its generalized use. In this thesis, we suggest novel solutions to two issues and we present an implementation of a THz 3D Imaging modality known as computed tomography. First, the handling of the THz beam is difficult. To overcome this, we explore two kinds of foam waveguides : polystyrene foam and silk foam. We use the polystyrene foam as a cladding for the THz two-wire waveguide. We show that the additional losses are offset by the mechanically robust and hermetical foam encapsulation. As for the silk foam, we show that the losses are one order of magnitude lower than those of solid silk. Here, the silk foam has the advantage of being biocompatible for biomedical and agro-alimentary applications. Second, the acquisition of the THz pulse is time-consuming. The slowest component in a regular THz-TDS system is the linear optical delay line. We implement a fast rotary delay line that is able to significantly reduce the overall time acquisition. Additionally, we present novel applications for THz. These applications were not possible before, because of the long time acquisition. Specifically, we observe, in real time, the evaporation of transparent liquids, the spray painting process, as well as the detection and thickness evaluation of moving objects. Third, we implement a THz 3D computed tomography imaging system. The THz-TDS allows multifrequency imaging and direct extraction of the complex refractive index. However, when doing computed tomography imaging on a THz-TDS system, several challenges arise, the main one being the time acquisition. Here, we present an early implementation of such a system. We discuss several issues and we present solutions to some

Biomaterials Out of Thin Air: In Situ, On-Demand Printing of Advanced Biocomposites: A New Materials Design and Production Technique Using 3D-Printed Arrays of Bioengineered Cells

We have completed the proof of concept described in our Phase I proposal, a two-material array of nonstructural proteins. We created an implementation of each step in our technology concept and demonstrated its critical functionality. The biological chassis and printing hardware we created as part of this work can be re-used for future work by inserting a material coding region upstream of the fluorescent tag. Overall, we showed that our technology concept is sound. The mission benefit analyses, as described in our Phase I proposal, are complete and contained in this report. These calculations show that our technology can save hundreds of kilograms of upmass for a potential planetary human habit construction mission: the mass per habitat module can be reduced by approximately one third if the biomaterials are manufactured on Earth and included in the mission upmass, and the full 240 kg per module can be saved if the materials are derived entirely from in situ resources. Mass savings between these two extremes is expected for an actual mission, depending on the level of in situ resource extraction technology. We have shown that continued advancement of this technology concept for use in a space mission environment is justified. Our survey of future development pathways proved extremely informative in light of the lessons learned from our proof of concept work and mission scenario analyses. For example, we were able for the first time to distinguish between the levels of functionality provided by production of structural proteins, other polymers such as polysaccharides, and true organic-inorganic composites such as bone and mineralized shell. This new information represents a significant advance in formulating specific applications, and key enabling technologies, for our proposed concept. We surveyed potential collaborations with other projects and synergies with enabling technologies that are developing. We have received requests for collaboration from other institutions, including labs at Stanford University and Drexel University. We have also received visits from industry, including Organovo, a tissue engineering company, and Autodesk, a major 3D and materials design software company. Finally, we have been in touch with the team behind the 2013 NIAC Phase ll 'Super Ball Bot-Structures for Planetary Landing and Exploration' and are planning to develop our biomaterial printing technology with the goal of enabling tensegrity-based rovers such as theirs to use lighter, more robust materials. A smooth transition from TRL 2 to TRL 3 assumes that the implementations of the technology concept which demonstrate critical functionality are also pathways for future development; while this is the case for most hardware or software projects, the multidisciplinary nature of our project, particularly the biological aspect of it, means that this is not always true. For example, as part of this work we showed that although there are large number of known genetic parts that correspond to non-structural materials, this is not true for sequences for structural organic proteins, let alone biominerals. These realizations allowed us to further subdivide our concept into more detailed development areas, some of which are clearly established at TRL 3, others of which were newly identified sub-technologies moved from TRL 1 to TRL 2. Similarly, although a single feasibility /benefit analysis is sufficient for advancement from TRL 2 to TRL 3, not all potential benefits to a technology concept as broad in scope as ours are apparent at TRL 2. Both our future pathways survey and our proof of concept work highlighted that the true mass savings potential of our technology concept cannot be quantified without modification of existing materials modelling tools to take into account the possibility of positional materials properties customization. Therefore, we have simultaneously both advanced one potential set of applications of our technology concept from TRL 2 to TRL 3 and also identified a previously unknown set of applications and advanced it from TRL 1 to TRL 2. Overall, we have moved the original formulation of our concept forward from TRL 2 to TRL 3, and the expanded formulation of it presented in this document has been advanced from a combination of TRL 1 and early 1RL 2 to an overall late TRL 2. We have also identified the key areas necessary for both short-term and long-term advancement, and made recommendations for specific future work in the most promising directions. With future work on a 1-2 year timeframe to continue advancement to overall TRL 3, we will be well positioned to begin work on a specific space mission technology insertion path

X-Ray microcalorimeter detectors - Technology developments for high energy astrophysics space missions

Improvements in the design, fabrication, and performance of astronomical detectors has ushered in the so-called era of multi messenger astrophysics, in which several different signals (electromagnetic waves, gravitational waves, neutrinos, cosmic rays) are processed to obtain detailed descriptions of their sources. Soft x-ray instrumentation has been developed in the last decades and used on board numerous space missions. This has allowed a deep understanding of several physical phenomena taking place in astrophysical sources of different scales from normal stars to galaxy clusters and huge black holes. On the other hand, imaging and spectral capabilities in the the hard x-rays are still lagging behind with high potentials of discovery area. Modern cryogenic microcalorimeters have two orders of magnitude or more better energy resolution with respect to CCD detectors at the same energy in the whole X-ray band. This significant improvement will permit important progress in high energy astrophysics thanks to the data that will be provided by future missions adopting this detector technology such as the ESA L2 mission Athena, the JAXA/NASA mission XRISM, both under development, or the NASA LYNX mission presently under investigation. The JAXA/NASA mission Hitomi, launched in 2016 and failed before starting normal operation, has already given a hint of the high potential of such detectors. Due to their very high sensitivity, X-ray cryogenic microcalorimeters need to be shielded from out of band radiation by the use of efficient thin filters. These microcalorimeters work by measuring the temperature increase caused by a photon that hits an X-ray absorber. In neutron transmutation doped germanium (NTD Ge) devices the temperature increase in the absorber is measured by a semiconductor thermometer made of germanium doped by the neutron transmutation doping technique. They are characterized by relatively low specific heat and low sensitivity to external magnetic fields. These characteristics make them promising detectors for hard X-ray detectors for space and laboratory applications. Research groups of the the X-ray Astronomy Calibration and Testing (XACT) Laboratory of the Osservatorio Astronomico di Palermo – Istituto Nazionale di Astrofisica (INAF-OAPA), and of the Dipartimento di Fisica e Chimica “Emilio Segrè” (DiFC) of the Università di Palermo have already developed experience related to the design, fabrication and testing of NTD Ge microcalorimeters. Furthermore, the research group has participated for many years in the design and development of filters for x-ray detectors in different space missions. This thesis concerns the development of materials and technologies for high energy microcalorimeters. In particular its aim is to design and fabricate thick bismuth absorbers for NTD germanium microcalorimeter arrays to extend their detection band toward hard X-ray energies. Filters for shielding microcalorimeters from different background radiation arriving on the detectors were also studied. The design and fabrication of thick bismuth absorbers for hard x-rays detection (20 keV ≤ E ≤ 100 keV) is part of an ongoing effort to develop arrays of NTD Ge microcalorimeters by planar technologies for astrophysical applications. One potential application of such detectors is in the high spectral resolution (∆E ~ 50 eV) investigation of the hard X-ray emission from the solar corona, which is the goal of a stratospheric balloon borne experiment concept named MIcrocalorimeters STratospheric ExpeRiment for solar hard X rays (MISTERX) presently under study at INAF-OAPA. The characterization activity of filters for microcalorimeters in also related to the implementation of the European Space Agency high energy mission named Athena (Advanced Telescopes for High Energy Astrophysics). This thesis describes the design, fabrication, and characterization of the bismuth absorbers, as well as the characterization of filters for Athena. Chapter one summarizes the working principles of NTD Ge microcalorimeters and their applications. Chapter 2 describes the design of the bismuth absorber array on suitable substrates. Chapter 3 focuses on the electroplating process for the bismuth layer deposition, with details about the design and fabrication of the microlithographic mask for the array patterning, and about the development of the microlithographic process for the array fabrication on the chosen substrates. The fabrication of 4 x 4 absorber arrays is also described. Chapter 4 reports on the characterization activity of deposited bismuth layers by different techniques; their morphology was investigated by scanning electron microscopy. The electrochemical impedance spectroscopy technique was used to increase grown layer quality. Fabricated arrays were also characterized. Chapter 5 describes the characterization activity for different filter prototype samples developed for Athena. Mechanical robustness, radio frequency attenuation and radiation damage caused by protons were evaluated. Radiation damage effects at different doses were in particular investigated on silicon nitride filters by scanning electron microscopy (SEM), atomic force microscopy (AFM), UV-Vis-IR spectroscopy and x-ray attenuation measurements. Details on both technical detector requirements and different sensor types are given in the Appendix

Integrated Actuation And Energy Harvesting In Prestressed Piezoelectric Synthetic Jets

With the looming energy crisis compounded by the global economic downturn there is an urgent need to increase energy efficiency and to discover new energy sources. An approach to solve this problem is to improve the efficiency of aerodynamic vehicles by using active flow control tools such as synthetic jet actuators. These devices are able to reduce fuel consumption and streamlined vehicle design by reducing drag and weight, and increasing maneuverability. Hence, the main goal of this dissertation is to study factors that affect the efficiency of synthetic jets by incorporating energy harvesting into actuator design using prestressed piezoelectric composites. Four state-of-the-art piezoelectric composites were chosen as active diaphragms in synthetic jet actuators. These composites not only overcome the inherent brittle and fragile nature of piezoelectric materials but also enhance domain movement which in turn enhances intrinsic contributions. With these varying characteristics among different types of composites, the intricacies of the synthetic jet design and its implementation increases. In addition the electrical power requirements of piezoelectric materials make the new SJA system a coupled multiphysics problem involving electro–mechanical and structural–fluid interactions. Due to the nature of this system, a design of experiments approach, a method of combining experiments and statistics, is utilized. Geometric and electro-mechanical factors are investigated using a fractional factorial design with peak synthetic jet velocity as a response variable. Furthermore, energy generated by the system oscillations is harvested with a prestressed composite and a piezo-polymer. Using response surface methodology the process is optimized under different temperatures and pressures to simulate harsh environmental conditions. Results of the fractional factorial experimental design showed that cavity dimensions and type of signal used to drive the synthetic jet actuator were statistically significant factors when studying peak jet velocity. The Bimorph (~50m/s) and the prestressed metal composite (~45m/s) generated similar peak jet velocities but the later is the most robust of all tested actuators. In addition, an alternate input signal to the composite, a sawtooth waveform, leads to jets formed with larger peak velocities at frequencies above 15Hz. The optimized factor levels for the energy harvesting process were identified as 237.6kPa, 3.7Hz, 1MΩ and 12°C and the power density measured at these conditions was 24.27µW/mm3. Finally, the SJA is integrated with an energy harvesting system and the power generated is stored into a large capacitor and a rechargeable battery. After approximately six hours of operation 5V of generated voltage is stored in a 330µF capacitor with the prestressed metal composite as the harvester. It is then demonstrated that energy harvested from the inherent vibrations of a SJA can be stored for later use. Then, the system proposed in this dissertation not only improves on the efficiency of aerodynamic bodies, but also harvests energy that is otherwise wasted

Control for an optically powered firing set using miniature photovoltaic arrays

The optically powered firing set looks to revolutionize the design of future electrical firing sets. Optically powered devices have many features that make them attractive, such as immunity to noise problems from Electromagnetic Interference (EMI) and Electromagnetic Radiation (EMR). Also, optically powered devices provide additional safety to prevent unintended usage and are small in volume in comparison to their electrical equivalent. These advancements have led to the design of a prototype firing set developed at Sandia National Laboratories. The main components are comprised of a miniature photovoltaic array (MPA) that transforms light energy to electrical energy and a capacitive discharge unit (CDU) used to store and deliver the transformed electrical energy to a detonator. In order for this system to be further optimized for implementation into an actual firing set, the output voltage state needs to be controlled and the temperature of the MPA and illuminating source minimized. This thesis reports on the development of an optical firing set model that represents the electrical, optical, and thermal characteristics of the system. A closed loop feedback control system with a PI controller is then developed to control the output voltage state as well as minimizing the MPA and illuminating source temperature

Technology 2001: The Second National Technology Transfer Conference and Exposition, volume 1

Papers from the technical sessions of the Technology 2001 Conference and Exposition are presented. The technical sessions featured discussions of advanced manufacturing, artificial intelligence, biotechnology, computer graphics and simulation, communications, data and information management, electronics, electro-optics, environmental technology, life sciences, materials science, medical advances, robotics, software engineering, and test and measurement

Gallium-Based Room Temperature Liquid Metals and its Application to Single Channel Two-Liquid Hyperelastic Capacitive Strain Sensors

abstract: Gallium-based liquid metals are of interest for a variety of applications including flexible electronics, soft robotics, and biomedical devices. Still, nano- to microscale device fabrication with these materials is challenging because of their strong adhesion to a majority of substrates. This unusual high adhesion is attributed to the formation of a thin oxide shell; however, its role in the adhesion process has not yet been established. In the first part of the thesis, we described a multiscale study aiming at understanding the fundamental mechanisms governing wetting and adhesion of gallium-based liquid metals. In particular, macroscale dynamic contact angle measurements were coupled with Scanning Electron Microscope (SEM) imaging to relate macroscopic drop adhesion to morphology of the liquid metal-surface interface. In addition, room temperature liquid-metal microfluidic devices are also attractive systems for hyperelastic strain sensing. Currently two types of liquid metal-based strain sensors exist for inplane measurements: single-microchannel resistive and two-microchannel capacitive devices. However, with a winding serpentine channel geometry, these sensors typically have a footprint of about a square centimeter, limiting the number of sensors that can be embedded into. In the second part of the thesis, firstly, simulations and an experimental setup consisting of two GaInSn filled tubes submerged within a dielectric liquid bath are used to quantify the effects of the cylindrical electrode geometry including diameter, spacing, and meniscus shape as well as dielectric constant of the insulating liquid and the presence of tubing on the overall system's capacitance. Furthermore, a procedure for fabricating the two-liquid capacitor within a single straight polydiemethylsiloxane channel is developed. Lastly, capacitance and response of this compact device to strain and operational issues arising from complex hydrodynamics near liquid-liquid and liquid-elastomer interfaces are described.Dissertation/ThesisMasters Thesis Materials Science and Engineering 201

Piezoelectric microstructured fibers via drawing of multimaterial preforms

We demonstrate planar laminated piezoelectric generators and piezoelectric microstructured fibers based on BaTiO3-polyvinylidene and carbon-loaded-polyethylene materials combinations. The laminated piezoelectric generators were assembled by sandwiching the electrospun BaTiO3-polyvinylidene mat between two carbon-loaded-polyethylene films. The piezoelectric microstructured fiber was fabricated via drawing of the multilayer fiber preform, and features a swissroll geometry that have ~10 alternating piezoelectric and conductive layers. Both piezoelectric generators have excellent mechanical durability, and could retain their piezoelectric performance after 3 day's cyclic bend-release tests. Compared to the laminated generators, the piezoelectric fibers are advantageous as they could be directly woven into large-area commercial fabrics. Potential applications of the proposed piezoelectric fibers include micro-power-generation and remote sensing in wearable, automotive and aerospace industries

NASA Tech Briefs, February 1996

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