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Physically based mechanical metaphors in architectural space planningArvin, Scott Anthony 30 September 2004 (has links)
Physically based space planning is a means for automating the conceptual design process by applying the physics of motion to space plan elements. This methodology provides for a responsive design process, allowing a designer to easily make decisions whose consequences propagate throughout the design. It combines the speed of automated design methods with the flexibility of manual design methods, while adding a highly interactive quality and a sense of collaboration with the design. The primary assumption is that a digital design tool based on a physics paradigm can facilitate the architectural space planning process. The hypotheses are that Newtonian dynamics can be used 1) to define mechanical metaphors to represent the elements in an architectural space plan, 2) to compute architectural space planning solutions, and 3) to interact with architectural space plans. I show that space plan elements can be represented as physical masses, that design objectives can be represented using mechanical metaphors such as springs, repulsion fields, and screw clamps, that a layout solution can be computed by using these elements in a dynamical simulation, and that the user can interact with that solution by applying forces that are also models of the same mechanical objects. I present a prototype software application that successfully implements this approach. A subjective evaluation of this prototype reveals that it demonstrates a feasible process for producing space plans, and that it can potentially improve the design process because of the quality of the manipulation and the enhanced opportunities for design exploration it provides to the designer. I found that an important characteristic of this approach is that representation, computation, and interaction are all defined using the same paradigm. This contrasts with most approaches to automated space planning, where these three characteristics are usually defined in completely different ways. Also emerging from this work is a new cognitive theory of design titled 'dynamical design imagery,' which proposes that the elements in a designer's mental imagery during the act of design are dynamic in nature and act as a dynamical system, rather than as static images that are modified in a piecewise algorithmic manner.
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Development and application of novel genetic transformation technologies in maize (Zea mays L.)Ahmad Abadi, Mohammad January 2007 (has links)
Plant genetic engineering approaches are of pivotal importance to both basic and applied research. However, rapid commercialization of genetically engineered crops, especially maize, raises several ecological and environmental concerns largely related to transgene flow via pollination. In most crops, the plastid genome is inherited uniparentally in a maternal manner. Consequently, a trait introduced into the plastid genome would not be transferred to the sexually compatible relatives of the crops via pollination. Thus, beside its several other advantages, plastid transformation provides transgene containment, and therefore, is an environmentally friendly approach for genetic engineering of crop plants. Reliable in vitro regeneration systems allowing repeated rounds of regeneration are of utmost importance to development of plastid transformation technologies in higher plants. While being the world’s major food crops, cereals are among the most difficult-to-handle plants in tissue culture which severely limits genetic engineering approaches. In maize, immature zygotic embryos provide the predominantly used material for establishing regeneration-competent cell or callus cultures for genetic transformation experiments. The procedures involved are demanding, laborious and time consuming and depend on greenhouse facilities. In one part of this work, a novel tissue culture and plant regeneration system was developed that uses maize leaf tissue and thus is independent of zygotic embryos and greenhouse facilities. Also, protocols were established for (i) the efficient induction of regeneration-competent callus from maize leaves in the dark, (ii) inducing highly regenerable callus in the light, and (iii) the use of leaf-derived callus for the generation of stably transformed maize plants. Furthermore, several selection methods were tested for developing a plastid transformation system in maize. However, stable plastid transformed maize plants could not be yet recovered. Possible explanations as well as suggestions for future attempts towards developing plastid transformation in maize are discussed. Nevertheless, these results represent a first essential step towards developing chloroplast transformation technology for maize, a method that requires multiple rounds of plant regeneration and selection to obtain genetically stable transgenic plants.
In order to apply the newly developed transformation system towards metabolic engineering of carotenoid biosynthesis, the daffodil phytoene synthase (PSY) gene was integrated into the maize genome. The results illustrate that expression of a recombinant PSY significantly increases carotenoid levels in leaves. The beta-carotene (pro-vitamin A) amounts in leaves of transgenic plants were increased by ~21% in comparison to the wild-type. These results represent evidence for maize to have significant potential to accumulate higher amounts of carotenoids, especially beta-carotene, through transgenic expression of phytoene synthases.
Finally, progresses were made towards developing transformation technologies in Peperomia (Piperaceae) by establishing an efficient leaf-based regeneration system. Also, factors determining plastid size and number in Peperomia, whose species display great interspecific variation in chloroplast size and number per cell, were investigated. The results suggest that organelle size and number are regulated in a tissue-specific manner rather than in dependency on the plastid type. Investigating plastid morphology in Peperomia species with giant chloroplasts, plasmatic connections between chloroplasts (stromules) were observed under the light microscope and in the absence of tissue fixation or GFP overexpression demonstrating the relevance of these structures in vivo. Furthermore, bacteria-like microorganisms were discovered within Peperomia cells, suggesting that this genus provides an interesting model not only for studying plastid biology but also for investigating plant-microbe interactions. / Pflanzliche Gentechnik spielt sowohl in der Grundlagenforschung als auch der Biotechnologie eine große Rolle. Allerdings bringt die landwirtschaftliche Nutzung gentechnisch veränderter Pflanzen (GM) ökologische Umweltrisiken mit sich, wie z.B. die Kreuzung GM Pflanzen mit sexuell kompatiblen Verwandten durch Fremdbestäubung. Gegenüber den Kerntransformanden haben Plastidtransformanden für die biotechnologische Nutzung große Vorteile, unter anderem da die Vererbung des Plastidgenoms bei höheren Angiospermen ausschließlich maternal geschieht. Somit kann ein Gentransfer transplastomischer Pflanzen über Pollen ausgeschlossen werden.
Zuverlässige in-vitro-Regenerationssysteme, die wiederholte Regenerationsrunden erlauben, sind von großem Wert für die Etablierung der Plastidentransformationstechnologie. Trotz Sein die Hauptgetreidenahrungsmittel der Welt, Zerealie Pflanzen gehören zu schwierigsten in der Gewebekultur zu handeln, die Annäherungen der genetischen Technik streng begrenzt. Im Mais werden hauptsächlich junge zygotische Embryonen für die Herstellung der Regenerations-kompetenten Kalluskulturen benutzt. Der Arbeitsaufwand dafür ist hoch und die Prozedur schwierig und von den Gewächshausbedingungen abhängig.
Im Rahmen dieser Arbeit wurden neue Gewebekultursysteme für Mais etabliert, welches junge Blattgewebe nutzt und somit unabhängig von Embryonen und Gewächshaus ist. Weiterhin wurden die aus Blättern gebildeten Kalluskulturen für die Generierung der genetisch veränderten Maispflanzen benutzt. Ebenso wurden verschiedene Selektionsmethoden für die Entwicklung eines Plastidentransformationssystems in Mais getestet. Jedoch konnten keine transplastomischen Maispflanzen erhalten werden. Sowohl die möglichen Ursachen als auch Vorschläge für weiterführende Versuche diesbezüglich werden im Rahmen dieser Arbeit diskutiert. Dennoch stellt diese Arbeit den ersten wesentlichen Schritt für die Entwicklung eines Plastidentransformationssystems in Mais vor.
In einem zweiten Teil dieses Projekts wird die erfolgreiche Integration der Narzissen Phytoene Synthase in das Maisgenom durch das neu entwickelte nukleäre Transformationssystem gezeigt. Dadurch konnte eine signifikante Steigerung um 17% des Gesamtcarotinoid- und 21% des Beta-Carotengehalts in Maisblättern beobachtet werden. Schließlich wurden Fortschritte für die Entwicklung eines Transformationssystems für Peperomia (Piperaceae) durch die Etablierung eines Regenerationssystems aus Blättern gemacht. Außerdem wurden Faktoren, die die Plastidengröße und –zahl bestimmen, untersucht. Diese Ergebnisse geben Hinweise darauf, dass die Organellengröße und –zahl eher gewebespezifisch als in Abhängigkeit vom Plastidentyp reguliert wird.
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Novel Microsystem Techniques for Liquid Manipulation and Pressure SensingMelin, Jessica January 2004 (has links)
Scaling down operations and functions into the fascinating micro world not only improve performance, lower costs, and enable easier integration, but also opens the door to new functionalities. This truly multidisciplinary thesis presents novel solutions to current and relevant challenges in the areas of 1) on-chip liquid manipulation which has applications in micro total analysis systems, medical diagnostics, and drug discovery and 2) pressure sensing which has an established market in the automotive and industrial processes industry. Especially in the area of liquid manipulation, the aim was to take advantage of forces and properties dominating on the micro scale whenever possible, rather than compensating for these effects, and to create solutions with universal appeal and application areas. In the area of liquid manipulation, this thesis discusses a novel method of passively synchronizing liquid movement on-chip based on liquid surface tension and device geometry. This technique has potential applications in timing independent processes, liquid-liquid interactions, and digitizing liquid movement. A fast and passive discrete sample micromixer is also presented based on the same principles. A unique way of direct access, bubble tolerant sample interfacing with flow-through microfluidics using a closed-open-closed channel is also introduced. This method can be used to regulate flow on-chip without the need for any moving parts or electrical contact. Moreover, work is presented on two types of out-of-plane electrospray ionization mass spectrometry (ESI-MS) emitter tips which mimic ideal mass spectrometry tips. Fabrication of these tips is uncomplicated and results in robust structures with good performance. In the field of pressure sensing, this thesis investigates a form based resonating principle. The Q factor of the sensor is improved by low pressure encapsulation and structure design. A novel technique for excitation and detection of resonant microsensors using 'burst' technology is also demonstrated. This method involves temporally separating excitation and detection, thereby eliminating crosstalk and the need for electrical feedthroughs. It also allows high voltages to be used with sensitive circuitry and a single electrode to be used for both excitation and detection.
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Controlled manipulation of microparticles utilizing magnetic and dielectrophoretic forcesJohansson, LarsErik January 2010 (has links)
This thesis presents some experimental work in the area of manipulation of microparticles. Manipulation of both magnetic and non magnetic beads as well as microorganisms are addressed. The work on magnetic bead manipulation is focused on controlled transport and release, on a micrometer level, of proteins bound to the bead surface. Experimental results for protein transport and release using a method based on magnetization/demagnetization of micron-sized magnetic elements patterned on a modified chip-surface are presented. Special attention has been placed on minimizing bead-surface interactions since sticking problems have shown to be of major importance when protein-coated beads are used. The work with non-magnetic microparticles is focused on the dielectrophoretic manipulation of microorganisms. Preliminary experimental results for trapping and spatial separation of bacteria, yeast and non-magnetic beads are presented. The overall goal was to investigate the use of dielectrophoresis for the separation of sub-populations of bacteria differing in, for example, protein content. This was, however, not possible to demonstrate using our methods.Within the non-magnetic microparticle work, a method for determining the conductivity of bacteria in bulk was also developed. The method is based on the continuous lowering of medium conductivity of a bacterialsuspension while monitoring the medium and suspension conductivities.
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En bild ljuger aldrig? : En studie om digitaliseringens inverkan på trovärdigheten i fotografier / A photograph never lies? : A study about the effects of digitalization in the truthworthiness in photographiesMuurman, Eeva-Leena, Svensson, Maria January 2005 (has links)
The concept of the photographic truth has had a special status for almost 200 years. Yet with the emerge of digital technology and especially digital photography there has been a loss of the particular connection photography has had in reference to reality. The aim of this study is to see in what ways digitalization has affected the credibility of photography from the perspective of professionals in the field of photography. The digital technology that has enabled the large-scale manipulation of photographies is not, however, the main reason for the decreased credibility of photography. The ongoing discussion about the available possibilities concerning digital imagery and manipulation has had a far more powerful effect on the concept of the photographic truth. Along with these possibilities a post-photographic photograph has seen the light of day. We discuss further some credibility problems caused by this new phenomenon; i.e. the post-photographic photographies can’t be considered to have the same status as the traditional photographies when it comes to presenting reality truthfully. We approached the subject through theory studies and methodically through personal interviews. Key words: credibility, digitalization, manipulation, remediation, reality, noeme, and the post-photographic era.
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Synthesis and Electric Field-Manipulation of High Aspect Ratio Barium TitanateLi, Junjia 2011 May 1900 (has links)
The objective of this thesis is to develop high dielectric constant nanoparticle dispersion for switchable aircraft antenna systems. Two steps were designed to achieve the objective. First, obtain high dielectric, high aspect ratio nanoparticles and disperse them in dielectric oil medium. Second, manipulate the particle-oil dispersion using an external alternating current (AC) electric field to increase the effective dielectric constant.
In order to obtain high dielectric dispersions, different sizes and shapes of titanium dioxide (TiO2) and barium titanate (BaTiO3) nanoparticles were purchased and measured. However, after a number of experiments detailed in the thesis, it was found that none of the commercially available nanoparticles could satisfy our requirements for a minimum effective dielectric constant. Thus, to achieve the goals above, we synthesized high aspect ratio BaTiO3 nanowires with BaC2O4 and TiO2 powders as precursors using a molten salt method. The as-synthesized BaTiO3 nanowires were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive spectroscopy (EDS) mapping. The nanowires have a diameter ranging from 100 nm to 300 nm, and their lengths range from 1.5 micrometers to 5 micrometers. Mechanical stirring and bath sonication were used to obtain even colloidal dispersions. Different concentrations of BaTiO3 nanoparticles well dispersed in the oil medium were successfully manipulated using AC electric field. To monitor the change in microstructure of BaTiO3 nanoparticles, optical microscopy was used to observe the alignment of particles in the sample under the applied electric field. Various parameters including the magnitude, frequency, and duration of the electric field, and the concentration of BaTiO3 nanoparticles were investigated to achieve the optimal alignment of nanoparticles. The experimental results were validated by theoretical analysis using Maxwell-Garnett mixing rule. It was demonstrated that the effective dielectric constant of the colloidal dispersions would increase with the increase of the magnitude, frequency and duration of applied electric field. Synthesized BaTiO3 nanowire-based dispersions exhibit significant enhancement of the effective dielectric constant compared to other colloidal materials. The effective dielectric constant of 5 wt percent BaTiO3-oil dispersions could reach up to 10 when aligned at 1000 V/mm electric field at 1 kHz frequency for 1 hour.
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Fitting Objects Into Holes : On the Development of Spatial Cognition SkillsÖrnkloo, Helena January 2007 (has links)
Children’s ability to manipulate objects is the end-point of several important developments. To imagine objects in different positions greatly improves children’s action capabilities. They can relate objects to each other successfully, and plan actions involving more than one object. We know that one-year-olds can insert an object into an aperture. Earlier research has focused on the start and goal of such actions, but ignored the way in between. This thesis shows that children are unable to fit an object into an aperture unless they can imagine the different projections of the object and rotate it in advance. The problem of how to proceed with an object-aperture matching was studied in 14- to 40-month-old children with a box, different holes and a set of fitting wooden blocks. Study I focused on how to orient a single object to make it fit. Studies II and III added a second object or aperture, introducing choice. In Study I there was a huge difference between 18 and 22 months in solving the fitting problem. Successful insertion was related to appropriate pre-adjustments. The older children pre-adjusted the object orientation before arriving at the aperture(s). The younger used a feedback strategy and that did not work for this task. To choose was more difficult than expected; one must not only choose one alternative, but also inhibit the other. Fifteen-month-olds were unable to choose between sizes and shapes, 20-month-olds could choose between sizes, 30-month-olds could choose between sizes and shapes, but not even 40-month-olds could choose between objects with different triangular cross-sections. Finally, the relationships between an object and an aperture, supporting surface or form were investigated. When comparing tasks requiring relationships between an object’s positive and an aperture’s negative form, between a 3D and a 2D, and between two 3D-forms, we found that the main difficulties is relating positive and negative form.
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Plasmonic Manipulation of Light for Sensing and Photovoltaic ApplicationsJanuary 2012 (has links)
Plasmonics is a successful new field of science and technology that exploits the exclusive optical properties of metallic nanostructures to manipulate and concentrate light at nano-meter length scales. When light hits the surface of gold or silver nanoparticles it can excite collective oscillations of the conduction electrons called surface plasmons. This surface plasmon undergoes two damping processes; it can decay into photon and reemit the plasmon energy as scattered energy or decay into electron-hole pair with the excitation energy equal to the energy of the plasmon resonance, known as absorption. This high energy electron subsequently undergoes into the carrier multiplication and eventually scatters into the electrons with lower energy. We used Finite-Difference Time-Domain (FDTD) and Finite-Element Method (Comsol) to design nanoscale structures to act as nanoantenna for light harvesting and consequently manipulating radiative and absorption properties of them for Sensing and Photovoltaic applications. To manipulate near and far field we designed our structures in a way that the bright and dark plasmon modes overlap and couple to each other. This process is called Fano resonance and introduces a transparency window in the far-field spectra. At the same time it increases the near-field enhancement. We applied the changes in near-field and far-field to SERS (Surface Enhanced Raman Spectroscopy) and LSPR (Localized Surface plasmon Resonance) shift for sensing purposes. We modeled Fano resonances with classical harmonic oscillator and reproduced the same feature with a simple equation of motion. We used this model to replicate scattering spectra from different geometries and explain the cathodoluminescence results obtained from nanoscale gold clusters structure. All of these nanoantenna optical properties and applications are due to the reemission ability of the plasmon energy to the vacuum and confining optical field, but the plasmon energy can decay into a high energy carrier rather than radiation. Photons coupled into metallic nanoantenna excite resonant plasmons, which can decay into energetic, hot electrons injected over a potential barrier at the nanoantenna-semiconductor interface, resulting in a photocurrent. We design a device which the range of its potential applications is extremely diverse. As silicon based detector capable of detecting sub-band gap photons, this device could be used in photovoltaic devices to harvest solar energy. Plasmon generated hot electrons can be used in photocatalytic dissociation of H2 molecules at the room temperature as well. The hot electrons in their higher energy states can populate the antibonding orbital of H2 molecules adsorbed on the metal surface and thus trigger the H2 molecule dissociation. The goal is to demonstrate the high efficiency of metallic photocatalytic systems by detecting the formation of HD molecules from the individual dissociation of two isotopes, H2 and D2. At the end we introduce lightning rod effect in metallic nanostructures and investigated the relation between the geometry properties of micrometer rod antennas and the electromagnetic field enhancement induced due to the lightning rod effect. At long wavelength, metals behave like perfect equipotential conductors and all the field enhancement results from the drop of potentials across the junctions between individual nanoparticles. This phenomenon is called lightning rod effect. By designing proper geometry we were able to utilize this effect to obtain enough electromagnetic enhancements in MIR region of spectrum to observe SEIRA signals from few hemoglobin molecules. Our simulation shows that the field enhancement obtained from this antenna does not depend sensitively on wavelength which is another advantage for SEIRA spectroscopy. We offered an analytical model to explore the coupling between the hemoglobin molecules and the Efield. We used this model to study the location effect of the molecule on the reflection signal. This technique allows us to detect the vibrational mode of molecules such as Hemoglobin in the real time and study their changes when the molecules are exposed to different environmental circumstances.
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Mobile manipulation in unstructured environments with haptic sensing and compliant jointsJain, Advait 22 August 2012 (has links)
We make two main contributions in this thesis. First, we present our approach to robot manipulation, which emphasizes the benefits of making contact with the world across all the surfaces of a manipulator with whole-arm tactile sensing and compliant actuation at the joints. In contrast, many current approaches to mobile manipulation assume most contact is a failure of the system, restrict contact to only occur at well modeled end effectors, and use stiff, precise control to avoid contact.
We develop a controller that enables robots with whole-arm tactile sensing and compliant actuation at the joints to reach to locations in high clutter while regulating contact forces. We assume
that low contact forces are benign and our controller does not place any penalty on contact forces below a threshold. Our controller only requires haptic sensing, handles multiple contacts across the surface of the manipulator, and does not need an explicit model of the environment prior to contact. It uses model predictive control with a time horizon of length one, and a linear quasi-static mechanical model that it constructs at each time step.
We show that our controller enables both a real and simulated robots to reach goal locations in high clutter with low contact forces. While doing so, the robots bend, compress, slide, and pivot around objects. To enable experiments on real robots, we also developed an inexpensive, flexible, and stretchable tactile sensor and covered large surfaces of two robot arms with these sensors. With an informal experiment, we show that our controller and sensor have the potential to enable robots to manipulate in close proximity to, and in contact with humans while keeping the contact forces low.
Second, we present an approach to give robots common sense about everyday forces in the form of probabilistic data-driven object-centric models of haptic interactions. These models can be shared by different robots for improved manipulation performance. We use pulling open doors, an important task for service robots, as an example to demonstrate our approach.
Specifically, we capture and model the statistics of forces while pulling open doors and drawers. Using a portable custom force and motion capture system, we create a database of forces as human operators pull open doors and drawers in six homes and one office. We then build data-driven
models of the expected forces while opening a mechanism, given knowledge of either its class (e.g, refrigerator) or the mechanism identity (e.g, a particular cabinet in Advait's kitchen). We demonstrate that these models can enable robots to detect anomalous conditions such as a locked door, or collisions between the door and the environment faster and with lower excess force applied to the door compared to methods that do not use a database of forces.
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Comanipulation Série Dextre pour la chirurgie Mini InvasiveHassan Zahraee, Ali 04 January 2012 (has links) (PDF)
Une chirurgie minimalement invasive (CMI), qui implique généralement une caméra endoscopique et des instruments de laparoscopie, peut sembler être la procédure chirurgicale idéale pour ses avantages apparents. Toutefois, en comparaison à la chirurgie ouverte, les limites spatiales et outils mécaniques posés sur les chirurgiens sont si élevés que, souvent, la CMI est abandonné pour des cas complexes et même quand elle est possible, la procédure nécessite une grande dextérité, calibre et expérience du chirurgien. Cette recherche a été motivée par la nécessité d'habiles instruments chirurgicaux qui offrent un contrôle intuitif et une interface ergonomique, avec l'objectif final de développer un instrument robotisé adapté aux interventions par laparoscopie. La recherche a été basée sur l'évaluation comparative des différentes interfaces, modes de contrôle et cinématiques, en utilisant un simulateur de réalité virtuelle, développée spécialement à cet effet. Les résultats montrent que: 1. l'interface optimale a un mode de contrôle WYSIWYD (ce que vous voyez est ce que vous faites) et est exploité par les doigt. 2. les mobilités distales motorisées de l'effecteur doivent produire deux degrés de liberté (DDL) indépendants pour la flexion et la rotation de l'effecteur. Ce qui est suffisant pour des gestes SIG complexes. 3. ajouter une libre articulation à la poignée de l'instrument permet au chirurgien d'avoir une posture ergonomique. 4. un trocart actif permettrait la rotation de l'arbre de l'instrument avec un joint libre. Cette recherche a également permis le développement d'un prototype de validation de concept. Le prototype a été testé avec succès, in vitro et in vivo sur un modèle porcin.
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