Dissertations / Theses on the topic 'Crystal development'
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Ashraf, Mujahid Al Islam. "Design and development of liquid crystal lenses." Australasian Digital Thesis Program, 2006. http://adt.lib.swin.edu.au/public/adt-VSWT20061117.145625.
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Thesis (MEng) - Swinburne University of Technology, Faculty of Engineering and Industrial Sciences, Centre for Micro-Photonics, 2006.A thesis submitted for the degree of Master of Engineering, Centre for Micro-Photonics, Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, 2006. Typescript. Includes bibliographical references (p. 74-77).
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Ashraf, Mujahid Al Islam, and n/a. "Design and development of liquid crystal lenses." Swinburne University of Technology. Faculty of Engineering and Industrial Sciences, 2006. http://adt.lib.swin.edu.au./public/adt-VSWT20061117.145625.
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The use of optics in the fields of nano-technology, telecommunication and
medicine has been growing exponentially in recent years. Application of liquid
crystals within optics has been a growing trend from flat screen displays to
variable focus lenses in a digital versatile discs.
One area of the recent developments within optics has been the development of
two-photon fluorescence microscopy and high-density three-dimensional optical
data storage. In such applications, where a light beam has to be focused deep
within the volume of bulk media, aberrations are introduced. The most dominant
aberration is spherical aberration which results from the mismatch in refractive
indices of the immersion and recording media. The aim of this thesis is to design a
liquid crystal lens for dynamic tube length compensation of the spherical
aberration.
Liquid crystal phase plates are used in everyday liquid crystal displays (LCDs)
such as mobile phones and calculators. The technologies required to manufacture
a liquid crystal phase plate are well understood. However, an application like
three-dimensional data storage requires different properties in the liquid crystal
phase plate, which are investigated in this thesis. To fabricate our liquid crystal
phase plate we used ZLI-5049-000 from MERCK as the liquid crystal medium,
with poly-vinyl alcohol (PVA) and Indium Tin Oxide (ITO) providing the
insulating and conducting layers, respectively. It has been demonstrated that
vacuum vapour deposition can be used to coat a glass substrate with ITO.
However, in order for the ITO coating to be conductive a method is developed
where the substrate is heated to 300oC before, during and after the coating.
Similarly, a method has been developed for producing a uniform 10 μm coating of
PVA on top of the ITO.
In order to produce a liquid crystal lens with the properties required to compensate
for spherical aberration an investigation into the properties of the liquid crystals is
first conducted. A liquid crystal phase plate described in chapter 3 is characterised
to determine the effect of the rubbing direction of the insulating layer and the
effective refractive index change with applied voltage. It has been demonstrated
that an effective change in refractive index of 0.11 can be achieved with 30 volts
applied across the ITO electrodes.
Based on the characterisation of the liquid crystal phase plate four different liquid
crystal lens designs have been proposed and tested. The lens designs are based
upon convergent and divergent lenses with different refractive index lens
substrates. It is determined that a liquid crystal lens with a divergent lens substrate
with a refractive index of 1.785 can be used to effectively compensate for
spherical aberration. This has been confirmed experimentally by using the liquid
crystal lens in a two-photon confocal microscope and measuring a increase in
detected intensity at a depth below the surface of a sample.
The research conducted in this thesis shows the ability to dynamically compensate
for spherical aberration introduced by a mismatch in the refractive indices
between the immersion and sample mediums. It has also been demonstrated that
new methods for fabricating the conductive and insulating layers are suitable for
producing a liquid crystal lens. A liquid crystal lens based on the research in this
thesis could be used in three-dimensional data storage or microscopy applications.
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Finnemeyer, Valerie A. "Development of Liquid Crystal Infrared Imaging Sensors." Kent State University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=kent1463139065.
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Kilby, Gregory Robert. "Infrared Methods Applied to Photonic Crystal Device Development." Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7156.
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Photonic crystal (PC) technology potentially offers lossless control of light propagation at a size scale near the order of the wavelength of light. The advantages and benefits of using such a technology in commercial devices are staggering. Yet, the commercial development of PC structures has been slow. Challenges associated with the repeatable fabrication and testing of structures has been identified as one cause of the slow development pace. To address these challenges, a development methodology that utilizes PC structures operating in the long-wavelength infrared is presented. One-dimensional PC structures, consisting of alternating regions of silicon and air are fabricated and characterized by measuring the transmittance or reflectance of the structure over the wavelength range from 5 쭠to 15 쭮 For the measurements, a model of the focused infrared beam is developed, tested and employed to characterize the structures. A novel measurement method, enabling the calculation of the single-angle plane-wave transmittances and reflectances from composite, multiple-angle transmittance and reflectance measurements, is formulated, tested and applied to PC structures. A new spectral characterization tool using a discretely tunable carbon-dioxide laser is presented and demonstrated. A measurement apparatus employing an FTIR microspectroscopy system is developed and measurements are recorded for the single-angle plane-wave characterization method. Single-angle plane-wave transmittances and reflectances calculated from composite multiple-angle measurements are shown to be in excellent agreement with theory. The results of this research are analyzed to identify the advantages and limitations of the long-wavelength infrared method.
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Ismail, Furrukh. "Photovoltaic Process Development and innovative Techniques." Thesis, Högskolan Dalarna, Elektroteknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:du-6453.
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Photovoltaic processing is one of the processes that have significance in semiconductor process line. It is complicated due to the no. of elements involved that directly or indirectly affect the processing and final yield. So mathematically or empirically we can’t say assertively about the results specially related with diffusion, antireflective coating and impurity poisoning. Here I have experimented and collected data on the mono-crystal silicon wafers with varying properties and outputs. Then by using neural network with available experimental data output required can be estimated which is further tested by the test data for authenticity. One can say that it’s a kind of process simulation with varying input of raw wafers to get desired yield of photovoltaic mono-crystal cells.
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Bahmann, Silvia. "Development of an evolutionary algorithm for crystal structure prediction." Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2014. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-141596.
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Die vorliegende Dissertation befasst sich mit der theoretischen Vorhersage neuer Materialien. Ein evolutionärer Algorithmus, der zur Lösung dieses globalen Optimierungsproblems Konzepte der natürlichen Evolution imitiert, wurde entwickelt und ist als Programmpaket EVO frei verfügbar. EVO findet zuverlässig sowohl bekannte als auch neuartige Kristallstrukturen. Beispielsweise wurden die Strukturen von Germaniumnitrofluorid, einer neue Borschicht und mit dem gekreuzten Graphen einer bisher unbekannte Kohlenstoffstruktur gefunden. Ferner wurde in der Arbeit gezeigt, dass das reine Auffinden solcher Strukturen der erste Teil einer erfolgreichen Vorhersage ist. Weitere aufwendige Berechnungen sind nötig, die Aufschluss über die Stabilität der hypothetischen Struktur geben und Aussagen über zu erwartende Materialeigenschaften liefern.
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Хайдер, А. М., and Ю. П. Мачехин. "Photonic crystal fibers technology development opprtunities in communications systems." Thesis, ХНУРЭ, 2016. http://openarchive.nure.ua/handle/document/8908.
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Drake, Philip. "The development of quartz crystal microbalance based chemical sensors." Thesis, University of Bath, 2000. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.323573.
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Bennett, Ian John. "Development and evaluation of alumina calcination." Thesis, University of Bath, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340929.
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This thesis focuses on a number of aspects governing the transformation of gibbsite, via intermediate phases, to a-alumina. These aspects include the size and morphology of the gibbsite grains, the influence of additions of foreign elements, the effect of a mechanical treatment of the gibbsite prior to calcination, and combinations of these factors. The materials were characterisedb y scanninge lectron microscopy, X-ray diffraction and surfacea rea measurementsF. or someo f the calcined materials an attempt was made to sinter the powders to a dense body to investigate if any of the treatments during calcination had an effect on this process. The literature review covers the current state of understanding of the production of bulk alumina powder by the Bayer process and the phase changes seen on calcination of precursors to the stable a-alumina phase. A detailed description of the phase changes is given and the various routes and conditions necessary for the transformations to occur are considered. The transformations are examined in relation to the morphology of the crystals and the variables controlling the phase transformation route are discussed. Calcination in air showed that the size of the gibbsite grain governs the calcination route taken to reach a-alumina. The standard gibbsites used in this work show a mixed calcination sequence transforming both via the boehmite phase, followed by the y, 8 and 0 phases, and via the x and K phases. The formation of boehmite is attributed to retention of water vapour within the grainDifferences in morphology of the starting materials showed that for the range of materials seen, the morphology of the grain is less important than its size. The super fine material confirmed that a small grain size transforms via the non-boehmite route only, with the other gibbsites taking intermediate routes as for the standard gibbsites. Of the additions made prior to calcination, aluminium fluoride was found to reduce the transformation temperature to a-alumina by approximately 300°C. Other additions had little effect on the transformation temperature although a reduction in grain size was seen with aluminium chloride. It was found that good mixing of the alumina fluoride was essential to obtain reliable and reproducible results. This is due to the small amounts of additive that are needed and the sensitivity of the process to concentration variations. Mineralisation of a range of gibbsites showed that the presence of sodium in the starting material was crucial in reducing the calcination temperature. This led to the conclusion that the sodium and fluoride react to form a liquid phase. The presence of a liquid phase increases the mobility of the aluminium and oxygen atoms resulting in a reduction of the transformation temperature. Fluoride additions to the gibbsites with different morphologies showed that the presence of sodium was the governing factor in reduction of the transformation temperature. Milling of the starting materials showed that there was a small reduction in the transformation temperature between some of the phases. The energy involved in milling leads to activation of the gibbsite. This activation takes the form of a reduction in the grain size and in a reduction of the crystallinity seen in the XRD patternFluoride additions during the calcination of sapphire with a standard gibbsite powder showed preferential grain growth. It was possible to initiate growth of small plate-like crystals on the polished surface of a piece of sapphire parallel to the basal plane. Crystal growth was also seen in scratches on a polished surface perpendicular to the basal plane
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Al-Dhafiri, Abdullah M. "CdS-CuₓS single crystal and thin film solar cells." Thesis, Durham University, 1988. http://etheses.dur.ac.uk/6617/.
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The work presented in this thesis is concerned with photovoltaic cells formed by plating CdS single crystals and thin films, and Cd(_y) Zn(1 _ y)S single crystals, with copper sulphide. An electroplating technique has been used to control the phase of copper sulphide by changing the electric field during its formation. Different phases of Cu(_x)S have been identified directly using Reflection High Energy Diffraction (RHEED), and indirectly from spectral response measurements. A dramatic change in the spectral response accompanying the reduction in the covellite response associated with an increase in that from chalcocite following argon heat treatment has been achieved. The change from the djurleite phase to that of chalcocite has also been obtained by using argon heat treatment for 5 minutes at 200 C. This effect was found to be reversible in that layers of chalcocite were converted to djurleite when air was used as the ambient for the heat treatment. C-V measurements have demonstrated that with increasing plating bias the donor concentration decreases at first before it assumes a constant value. This led to the effect of decreasing the junction capacitance as the width of the depletion region changed. The problem of the stability of the CdS-Cu(_2)S photovoltaic devices formed by wet plating" is addressed by studying the combined effects of the substrate onto which the CdS is deposited and the ambient used during annealing. Thin film cells have been prepared on both Ag/Cr and SnO substrates, and the device characteristics for each have been investigated as a function of annealing ambient. The results have shown that devices formed on Ag/Cr substrates were more stable following annealing in air than in argon, while the converse was true for cells fabricated on SnO(_x) substrates. The degradation effects of CdS-Cu(_2) S photovoltaic cells have been investigated. While devices stored in the dark showed little or no degradation, those maintained under illumination exhibited a significant deterioration in all operational parameters over a four week period. As far as the combined effect of temperature and ambient on the stability of cells are concerned, it was found that the ageing of devices in argon at room temperature in the dark was negligible, and moreover the fill factor was observed to improve marginally. When the devices were stored in the same ambient conditions at 50 C, they showed a significant improvement in the fill factor, but simultaneously exhibited a considerable reduction in the short circuit current. This process was reversible, since the sensitivity of degraded devices could be restored by annealing them in a hydrogen/nitrogen mixture. By comparing Electron Spectroscopy for Chemical Analysis (ESCA) studies with solar cell device characteristics, it has been shown that the formation of copper oxide on the Cu(_2)S surface plays a significant role in the degradation of CdS-Cu(_2) S devices. The extent of the cross-over between the dark and light J-V characteristics is a function of the period of etching used prior to junction formation. The variation of current and diode factor has been established as a function of the bias value. The dependence of forward current on the temperature at fixed forward voltage has also been investigated. Finally this work has shown that an increase in V(_oc) can be achieved when Cd(_0◦8)Zn(_0◦2)S is used as a base material for solar cells instead of CdS. Different traps were identified through a photocapacitance investigation. An important trap was found at 0.78eV below the conduction band. It has been demonstrated that the effect of this level was found to be diminished much more slowly when the annealing was carried out in argon rather than in air. This level may play an important role in the Cd(0◦8) Zn(0◦2)S-Cu(_2)S solar cell properties.
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Maclaren, Donald Angus. "Development of a single crystal mirror for scanning helium microscopy." Thesis, University of Cambridge, 2002. https://www.repository.cam.ac.uk/handle/1810/251834.
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Assefa, Solomon 1979. "The development of novel passive and active photonic-crystal devices." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/18053.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2004.Includes bibliographical references (p. 158-169).
Photonic crystals are anticipated to have impact on large-scale photonic integrated circuits by allowing the creation of compact and efficient devices such as waveguides, splitters, microcavity filters, light emitting diodes, and lasers. Previous experimental research has mainly focused on photonic crystals composed of a lattice of air holes etched into dielectric slabs. This thesis discusses the design, fabrication, and characterization of the "inverse" structure, a square lattice of dielectric-rods in air. Bandgap guiding of 1.5 lam light is experimentally demonstrated for a photonic-crystal waveguide created by introducing a line-defect of smaller-radii rods. To provide efficient optical coupling between input/output dielectric waveguides and the photonic-crystal waveguide, an adiabatic taper having two stages is employed. Furthermore, the thesis investigates novel photonic-crystal devices and fabrication schemes. An expose-develop-etch (EDE) method is utilized to fabricate rod-based photonic-crystal devices in III-V and SOI material systems. The thesis also presents an electrically-activated linear-waveguide photonic-crystal laser. A compact microcavity is created by introducing a defect inside a one-dimensional photonic crystal. Electrical-activation and edge-emission are achieved by patterning microcavity waveguides into p-i-n-doped epitaxial heterostructures. The compact photonic-crystal laser is anticipated to have impact on the integration of optical devices on the same chip.
Solomon Assefa.
Ph.D.
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Binns, Jack. "Development of high-pressure single-crystal neutron diffraction on KOALA." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/20416.
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This thesis project has focused on the development of high-pressure single-crystal diffraction experiments on the neutron Laue diffractometer KOALA at the OPAL reactor at ANSTO, Australia. Over the course of this project several candidate systems have been studied under conditions of high-pressure using X-ray diffraction with a view to their use in developmental experiments on KOALA. The results of two high-pressure KOALA experiments are presented as well as the notable results from X-ray diffraction on the candidate systems. The first experiment on hexamethylenetetramine provided valuable insights into how reduced crystallite size and reciprocal-space access affects data collected on KOALA. In addition, data treatment techniques were developed to deal with the unique and challenging high-pressure Laue data, including corrections for attenuation due to the cell body. The ability to collect data through the body of cell prompted a further experiment on the complex, low-symmetry structure of the amino acid l-arginine dihydrate. Despite the smaller crystal size and dominant parasitic scattering from the diamond-anvil cell, the data collected allow a full anisotropic refinement of hexamethylenetetramine with bond lengths and angles that agree with literature data within experimental error. This technique is highly suited to low-symmetry crystals, as shown by the successful refinement of data from a l-arginine dihydrate crystal. In such cases the transmission of diffracted beams results in higher completeness values than are possible with X-rays. The hydrogen-bonded ferroelectric rubidium hydrogensulfate was the subject of ambient-pressure experiments on KOALA investigating the nature of the ferroelectric transition. Further high-pressure X-ray diffraction studies were carried out to resolve the structures of phases at high-pressure and to investigate the ferroelectric transition under pressure. The potassium cobalt citrate metal-organic framework UTSA-16 has shown a wide variety of pressure-mediated framework-solvent interactions including negative linear compressibility, the ordering of potassium ions, and coordination changes which were investigated by high-pressure single-crystal and powder X-ray diffraction. These behaviors are rationalised by examination of the structural changes occurring in the framework under pressure. Two members of the widely studied alkylammonium tetrachlorometallate family, tetramethylammonium tetrachloroferrate(III) and tetramethylammonium tetrachlorogallate(III), display numerous phase transitions with temperature. The structures of these phases have been determined for the first time, and the contrast between the two materials explored with first-principles calculations.
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Yeldandi, Satish. "Development of fabrication processes for Si and GaN photonic crystal structures." Morgantown, W. Va. : [West Virginia University Libraries], 2008. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=5915.
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Thesis (M.S.)--West Virginia University, 2008.Title from document title page. Document formatted into pages; contains xi, 99 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 80-83).
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Alankar, Alankar. "Development of a 3D microstructure sensitive crystal plasticity model for aluminum." Pullman, Wash. : Washington State University, 2010. http://www.dissertations.wsu.edu/Dissertations/Spring2010/A_Alankar_020910.pdf.
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Bougas, Vassilis. "The development of a crystal modulator using a multipath reflection technique." Thesis, London Metropolitan University, 1993. http://repository.londonmet.ac.uk/3301/.
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An AOP lumped crystal transverse modulator has been developed, based upon a novel crystal cut, which operates at much lower driving voltages than presently available commercial state of the art modulators. With the latter, the modulation bandwidth is limited by the requirement for driving voltages in the range of 115V to 250V, which are difficult and expensive to produce using existing semiconductor technology. The reduction in driving voltage leads to an increased modulation bandwidth; low voltage wideband drivers are readily available. The modulator's novelty lies in a composite crystal scheme which allows a light beam to be reflected back and forth many times. The voltage requirement is reduced by a factor dependent on the number of times the light beam passes through the crystals. This modulator does not require a half wave plate and can therefore operate at any optical wavelength as is also the case with some of the existing designs. But in addition, unlike the existing designs, this novel modulator allows for multicolour multibeam operation. Using four AOP crystals (15.0mm length, 16.5mm width and 2.5mm thickness) a half wave voltage of 65V has been achieved after seven passes. The extinction ratios obtained were in the range of 50:1 to 100:1. A theory developed and supported by experimental results shows that the extinction ratio depends upon the angle of propagation of the light bean through the crystals. Improvements in this area are suggested. Finally, a technique for extending the operational bandwidth of any modulator is presented. The bandwidth of the multipath modulator was 70MHz.
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Plana, Ruiz Sergi. "Development & Implementation of an Electron Diffraction Approach for Crystal Structure Analysis." Doctoral thesis, Universitat de Barcelona, 2021. http://hdl.handle.net/10803/670887.
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The application of electron diffraction to crystallographically characterize all kinds of materials has experienced new developments that have attracted some attention in recent years. A large number of structural analyses from different compounds have been already carried out with the help of 3D electron diffraction data that were not possible with the available X-ray methods. The use of a transmission electron microscope as an electron nano-diffractometer has proved to be advantageous when diffraction data from single nanocrystals are required, for instance in phase mixtures. In this way, the individual phases do not have to be purely synthesized, which always involves the risk of structural changes. The work presented here includes the development and implementation of a novel and universal routine for the accurate and reliable acquisition of electron diffraction data. It contains the alignment of the transmission electron microscope in order to set a quasi-parallel and precessed beam suitable for the acquisition of this kind of data, and the description and comparison of the developed technique to the other methods already available. This novel acquisition method has been called fast and automated diffraction tomography (Fast-ADT) and it is based on two consecutive tilt scans of the goniometric stage of the microscope; one to image the crystal and generate a crystal tracking file, and a second one to acquire the diffraction patterns while the beam is automatically shifted to follow the crystal at the different tilt angles. Such technique has been implemented in different experimental setups to test different detectors as well as different samplings of the diffraction space to point out their advantages and hindrances. The potential of this new data collection strategy to solve various crystallographic problems is illustrated using three known materials: barite, an inorganic salt stable under the electron beam used to check the level of accuracy that can be obtained from electron diffraction, RUB-5, a layered silicate with disordered features to show the advantage of high frame-rate cameras, and the pi-ferrosilicide, a crystalline phase from a commercial alloy measured to demonstrate how electron diffraction can reliably determine absolute structures. In addition, two unknown crystal structures from commercial products are fully determined and refined. The first one is the dehydrated DRED1 molecular crystal, an inorganic dye used in textile applications, which has been solved ab initio revealing the 46 non-hydrogen atoms of the two independent molecules in P-1. Furthermore, the structure refinement based on intensities calculated according to the dynamical diffraction theory has proved the position of some of the hydrogens, confirming the square-like H-bond network initially found from a Rietveld refinement based on a X-ray powder diffractogram. Finally, the incommensurate modulated structure of one of the polymorphs of dicalcium silicate (belite), a major constituent of cement, has been comprehensively characterized only by means of electron diffraction. Such crystal structure has been known since 1971 but the observed modulation has never been fully studied. Here, the Fast-ADT technique is presented as a robust acquisition method to systematically identify and properly characterize different crystallographic phases and features of powder mixtures. In this particular case, the precise knowledge of the different crystal structures in cement clinkers, such as the alpha’H-C2S, enables the exact phase analysis of these industrial phase mixtures directly from the manufacturing process, and paves the way for its CO2 emissions reduction that, at the moment, adds up to 5% of the global anthropogenic emission. In this context, a novel technique for the collection of 3D electron diffraction datasets has been successfully developed and implemented to increase the range of reliable available tools for the characterization of atomic structures from different materials.L’aplicació de la difracció d’electrons per caracteritzar cristal·logràficament tot tipus de materials ha experimentat nous desenvolupaments que han cridat certa atenció durant aquests últims anys. Un gran nombre d’anàlisis estructurals en diferents compostos ja s’han dut a terme amb l’ajut de dades tridimensionals de difracció d’electrons que no eren possibles amb els habituals mètodes de raigs X. L’ús d'un microscopi electrònic de transmissió com a nano-difractòmetre d’electrons ha demostrat ser molt més beneficiós quan es requereixen dades de difracció de nanocristalls individuals, per exemple en mescles de fases cristal·logràfiques. D’aquesta manera, les fases individuals no s’han de sintetitzar en estat pur, fet que sempre comporta el risc de canvis estructurals. El treball presentat aquí inclou el desenvolupament i implementació d’una nova rutina universal per l’adquisició precisa i fiable de dades de difracció d’electrons. El potencial d’aquesta nova estratègia de recopilació de dades per resoldre diversos problemes cristal·logràfics s’il·lustra mitjançant tres materials coneguts. A més a més, dues estructures cristal·lines desconegudes de productes comercials han estat determinades i refinades completament; un colorant orgànic de baixa simetria i una estructura modulada incommensurada d’un component principal del ciment. En particular, el coneixement precís de les diferents estructures cristal·lines dels clinkers de ciment, com ara la alpha’H-C2S, permet l’anàlisi exacta de les fases d'aquestes mescles industrials extretes directament del procés de fabricació, i facilita el seu estudi per reduir les emissions de CO2.
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Begbie, Mark. "Experimental development of liquid crystal spatial light modulator based coherent optical correlators." Thesis, University of Edinburgh, 1999. http://hdl.handle.net/1842/10774.
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This work describes an experimentally based investigation into the use of spatial light modulators in coherent optical processing systems. The initial stages of the work revolve around designing a VanderLugt type optical correlator based upon two spatial light modulator devices. The spatial light modulators employed in the design are 256 x 256 pixel displays previously designed within the research group. We present the design specification and projected optical performance for a coherent optical correlator designed around these modulators. Alongside the development of the optical processing system, we present an investigation into possible processing algorithms and applications of the system. We investigate optical correlation and its application in morphological image processing. This, together with the use of stereo imagery and novel range analysis methods, provides the basis for an optical processing strategy to be implemented using the optical processor. Simulation results are presented showing the performance benefits provided by range analysis over direct correlation for target recognition, specifically for a group of targets similar to appearance to road signs. Initial optical correlator results are presented, showing significant shortcomings in the performance of the optical system. An experimental process of analysis reveals the primary source of signal degradation to be caused by poor performance of the spatial light modulators. This forces a change of track in the flow of the project towards a detailed investigation of the display device properties.
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Khac, Do Nguyen. "Situated cognition and Agile software development: A comparison of three methods." Thesis, Linköpings universitet, Institutionen för datavetenskap, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-62824.
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Agile programming methods have become popular in software development projects. These methods increase productivity and support teamwork processes. In this thesis, we have analyzed three well-known Agile methods - Scrum, Extreme Programming and Crystal Orange - from the perspective of situated cognition to investigate how well the methods support cognition. Specifically, we looked at how the methods aid memory and attention through the use of external representations. The study suggests that the methods support different aspects of situated cognition reasonably well. However, among the investigated methods, Scrum stands out due to aspects of task representation (progress charts), its approaches to externalize what-to-do (memory), and the means to focus on the important programming tasks for the day (attention).
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Park, Jinwoo. "Synthesis and Development of Helical Functional Polymers using Advanced Chiral Liquid Crystal Fields." 京都大学 (Kyoto University), 2015. http://hdl.handle.net/2433/199336.
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Meade, Shawn O. "Development of a DNA multiplexing system utilizing encoded porous silica photonic crystal particles." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2008. http://wwwlib.umi.com/cr/ucsd/fullcit?p3306682.
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Thesis (Ph. D.)--University of California, San Diego, 2008.Title from first page of PDF file (viewed June 12, 2008). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references.
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Zafiropoulos, Nicholas A. Lin Wenbin. "Development of new materials for applications in liquid crystal technologies and biofuel production." Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2008. http://dc.lib.unc.edu/u?/etd,1523.
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Thesis (Ph. D.)--University of North Carolina at Chapel Hill, 2008.Title from electronic title page (viewed Sep. 16, 2008). "... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Chemistry." Discipline: Chemistry; Department/School: Chemistry.
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Lane, Christopher John Leslie. "The development of a 2D ultrasonic array inspection for single crystal turbine blades." Thesis, University of Bristol, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.651312.
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The aim of this thesis is to design and evaluate a non-destructive evaluation (NDE) system for the inspection of single crystal turbine blades. Turbine blades are the components within jet-engines that convert the hot, high-pressure gas exiting the combustion stage into mechanical power. During operation, these components are highly stressed and are surrounded by extremely high gas temperatures. As such, there is the potential for defects to initiate in-service. One way to ensure the structural integrity of these engine components is by periodically inspecting them for defects. The ability of the inspection to be performed in situ is highly advantageous, as this eliminates the cost and time delay associated with removing the turbine blades from the engine prior to inspection. A 20 ultrasonic phased array system was chosen for this project, as these systems can perform rapid volumetric inspections whilst being portable enough to be used in situ. Modem turbine blades are manufactured from single crystal nickel-based superalloys for the excellent mechanical properties these materials exhibit at elevated temperatures. However, these materials are elastically anisotropic. The propagation of ultrasonic waves through anisotropic materials is far more complex than the isotropic case. This causes significant difficulties when inspecting anisotropic single crystal components with ultrasonic arrays. Therefore, analytical models are developed to predict the propagation of ultrasonic waves in anisotropic materials. These models are used to correct an ultrasonic imaging algorithm to account for the anisotropic behaviour. To implement the corrected algorithm effectively, the orientation of the crystal in the component under inspection must be known. Therefore, crystallographic orientation methods using 20 ultrasonic arrays are developed and evaluated. The corrected algorithms and crystallographic orientation methods are used to develop an in situ 20 ultrasonic array inspection for a specific high-pressure single crystal turbine blade. The inspection is designed to detect and size cracking in the root section of the turbine blade. The developed inspection system is fully evaluated in a quantitative manner for its defect detection sensitivity and sizing capability.
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Tran, Lucky. "Development of Full Surface Transient Thermochromic Liquid Crystal Technique for Internal Cooling Channels." Master's thesis, University of Central Florida, 2014. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/6371.
Full textAbstract:
Proper design of high performance industrial heat transfer equipment relies on accurate knowledge and prediction of the thermal boundary conditions. In order to enhance the overall gas turbine efficiency, advancements in cooling technology for gas turbines and related applications are continuously investigated to increase the turbine inlet temperature without compromising the durability of the materials used.
For detailed design, local distributions are needed in addition to bulk quantities. Detailed local distributions require advanced experimental techniques whereas they are readily available using numerical tools. Numerical predictions using a computational fluid dynamics approach with popular turbulence models are benchmarked against a semi-empirical correlation for the friction in a circular channel with repeated-rib roughness to demonstrate some shortcomings of the models used. Numerical predictions varied widely depending on the turbulence modelling approach used. The need for a compatible experimental dataset to accompany numerical simulations was discussed.
An exact, closed-form analytical solution to the enhanced lumped capacitance model is derived. The temperature evolution in a representative 2D turbulated surface is simulated using Fluent to validate the model and its exact solution. A case including an interface contact resistance was included as well as various rib sizes to test the validity of the model over a range of conditions. The analysis was extended to the inter-rib region to investigate the extent and magnitude of the influence of the metallic rib features on the apparent heat transfer coefficients in the inter-rib region. It was found that the thermal contamination is limited only to the regions closest to the base of the rib feature.
An experimental setup was developed, capable of measuring the local heat transfer distributions on all four channel walls of a rectangular channel (with aspect ratios between 1 and 5) at Reynolds numbers up to 150,000. The setup utilizes a transient thermochromic liquid crystals technique using narrow band crystals and a four camera setup. The setup is used to test a square channel with ribs applied to one wall. Using the transient thermochromic liquid crystals technique and applying it underneath high conductivity, metallic surface features, it is possible to calculate the heat transfer coefficient using a lumped heat capacitance approach. The enhanced lumped capacitance model is used to account for heat conduction into the substrate material. Rohacell and aluminum ribs adhered to the surface were used to tandem to validate the hybrid technique against the standard technique. Local data was also used to investigate the effect of thermal contamination. Thermal contamination observed empirically was more optimistic than numerical predictions.
Traditional transient thermochromic liquid crystals technique utilizes the time-to-arrival of the peak intensity of the green color signal. The technique has been extended to utilize both the red and green color signals, increasing the throughput by recovering unused data while also allowing for a reduction in the experimental uncertainty of the calculated heat transfer coefficient. The over-determined system was solved using an un-weighted least squares approach. Uncertainty analysis of the multi-color technique demonstrated its superior performance over the single-color technique. The multi-color technique has the advantage of improved experimental uncertainty while being easy to implement.M.S.M.E.
Masters
Mechanical and Aerospace Engineering
Engineering and Computer Science
Mechanical Engineering; Thermo-Fluids Track
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Chong, Samantha Yu-Ling. "Development of novel evolutionary algorithms for crystal structure determination from powder diffraction data." Thesis, University of Birmingham, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.434699.
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Shrauger, Vernon Eugene. "Development of a silicon VLSI optically addressed liquid crystal smart spatial light modulator." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/10517.
Full textAbstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1997.Includes bibliographical references (leaves 131-137).
by Vernon Eugene Shrauger.
Ph.D.
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Sangam, Ramyaa Ramesh. "Development of Polychromatic Laser Beacon Fiber Coupling System Based on Photonic Crystal Fibers." University of Dayton / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1386943018.
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Chung, David. "Development of system level integration of compact RF components on multilayer liquid crystal polymer (LCP)." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/42763.
Full textAbstract:
A system packaging level approach on liquid crystal polymer (LCP) was proposed for low cost, lightweight, and compact wireless communication systems. Via technology was explored for V-band W-band transitions and an active cooling system that are essential for compact multilayer integration. RF MEMS switches were fabricated and integrated at the component level to enable multi-functional devices with optimal performance. A pattern reconfigurable antenna for MIMO applications and 3D phase shifters for phased array antennas that use RF MEMS switches were presented. In addition, a lightweight expandable array was designed and measured with up to 256 elements on multilayer LCP integrated at the system level. Furthermore, a 60 GHz multilayer transceiver front end device with simultaneous transmit and receive was designed and measured for low cost 60 GHz applications. The wide variety of multilayer LCP applications integrated at the system level shows a promising future for the next generation low cost lightweight wireless communication systems.
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Joshi, Onkar D. "Development of a solvent free continuous co-crystallisation technique for carbamazepine ¿ saccharin." Thesis, University of Bradford, 2012. http://hdl.handle.net/10454/5697.
Full textAbstract:
Co-crystals are emerging as a potential area in the field of crystal designing as it
improves material¿s physicochemical properties. Many groups are working on the
development of newer techniques for the preparation of co-crystals, which can be scalable
and contribute to the green agenda. Being continuous and scalable technique, our own
developed twin screw extrusion mediated solvent free continuous co-crystallisation (SFCC)
technique has been used for the preparation of carbamazepine: saccharin co-crystal.
Carbamazepine has been used as a model drug since it shows challenges such as low
solubility (BCS class II), polymorphism and thermolabile nature whilst, saccharin was used
as a co-former.
Effect of extrusion processing parameters such as shear, temperature and screw speed on cocrystallisation
has been studied. In addition to this, effect of particle size of co-crystal
components, use of hydrated form of carbamazepine, addition of solvent and application of
reverse elements on the purity of co-crystal was understood. Use of carbamazepine dihydrate
as a starting component yields pure co-crystals. The addition of small amount of polar solvent
in anhydrous carbamazepine also yields pure co-crystals whereas particle size did not show
any significant effect. Result showed that selection of processing temperature near to eutectic,
moderate shear and increase in residence time of component mixture in mixing zone was
mainly responsible for co-crystallisation. The extrudates were mainly characterised by
XRPD, DSC and in-vitro dissolution tests. Pure co-crystals prepared by addition of highly
Development of a solvent free continuous co-crystallisation technique for carbamazepine-saccharin ii
polar solvent have been showed drug release identical to that of pure co-crystals prepared by
solvent crystallisation.
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Strasser, Patric. "The development of a fabrication process for passive photonic crystal devices in InP / InGaAsP /." Zürich : ETH, 2008. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=18062.
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Clarke, Colin. "Development of an automated identification system for nano-crystal encoded microspheres in flow cytometry." Thesis, Cranfield University, 2008. http://dspace.lib.cranfield.ac.uk/handle/1826/4036.
Full textAbstract:
Quantum dot encoded microspheres (QDEMs) offer much potential for bead based identification of a variety of biomolecules via flow cytometry (FCM). To date, QDEM subpopulation classification from FCM has required significant instrument modification or multiparameter gating. It is unclear whether or not current data analysis approaches can handle the increased multiplexed capacity offered by these novel encoding schemes. In this thesis the drawbacks of currently available data analysis techniques are demonstrated and novel classification methods proposed to overcome these limitations. A commercially available 20 code QDEM library with fluorescent emissions at 4 distinct wavelengths and 4 different intensity levels was analysed using flow cytometry. Multiparameter gating (MPG) a readily available classification method for subpopulations in FCM was evaluated. A support vector machine (SVM) and two types of artificial neural networks (ANNs), a multilayer perceptron (MLP) and probabilistic radial basis function (PRBF) were also considered. For the supervised models rigorous parameter selection using cross validation (CV) was used to construct the optimum models. Independent test set validation was also carried out. As a further test, external validation of the classifiers was performed using multiplexed QDEMs solutions. The performance of MPG was poor (average misclassification (MC) rate = 9.7%) was a time consuming process requiring fine adjustment of the gates, classifications made on the dataset were poor with multiple classifications on single events and as the multiplex capacity increases the performance is likely to decrease. The SVM had the best performance in independent test validation with 96.33% accuracy on the independent testing (MLP = 96.12%, PRBF = 94.38%). Furthermore the performance of the SVM was superior to both MPG and both ANNs for the external validation set with an average MC rate for MLP = 6.1% and PRBF = 7.5% whereas the SVM MC rate was 2.9%. Assuming that the external test solutions were homogenous the variance between classified results should be minimal hence, the variance of correct classifications (CCs) was used as an additional indicator of classifier performance. The SVM demonstrates the lowest variance for each of the external validation solutions (average σ 2 = 31479) some 50% lower than that of MPG. As a conclusion to the development of the classifier, a user friendly software system has been developed to allow construction and evaluation of multiclass SVMs for use by FCM practitioners in the laboratory. SVMs are a promising classifier for QDEMs that can be rapidly trained and classifications made in real time using standard FCM instrumentation. It is hoped that this work will advance SAT for bioanalytical applications.
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Habershon, Scott. "Development and optimization of computational techniques for crystal structure determination from powder diffraction data." Thesis, University of Birmingham, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.421732.
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Bell, Duncan. "Development of differential evolution algorithms applied to crystal structure solution from powder diffraction data." Thesis, University of Birmingham, 2012. http://etheses.bham.ac.uk//id/eprint/3942/.
Full textAbstract:
An understanding of the crystal structure can aid in the rationalisation of physicochemical properties exhibited by a crystalline material. Advances in the area of direct space crystal structure solution means that it is becoming easier to determine crystal structures from powder diffraction data. However, due to the number of structural models generated during structure solution calculations, direct space methods are computationally demanding. Work presented in this thesis reports the optimisation of a differential evolution (DE) algorithm and a cultural differential evolution (CDE) algorithm to reduce the computational demands of direct space methods. Characteristics particular to certain crystal structures are identified as having a significant effect on the efficiency and robustness of structure solution calculations by DE and CDE. The development of a new algorithm that closely mimics the natural evolution of a species is discussed. Results presented in this thesis demonstrate that this new algorithm is significantly more efficient than the DE algorithm. Despite the complexity of powder diffraction patterns recorded for biphasic crystalline materials, in this thesis, the successful development and application of a direct space method to the simultaneous structure solution of two crystals from a biphasic powder pattern is reported.
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Cheney, Miranda L. "The Role of Cocrystals in Solid-State Synthesis of Imides and the Development of Novel Crystalline Forms of Active Pharmaceutical Ingredients." Scholar Commons, 2009. http://scholarcommons.usf.edu/etd/3693.
Full textAbstract:
With a greater understanding of the fundamentals of crystal engineering lays the
potential for the development of a vast array of novel materials for a plethora of
applications. Addressed herein is the latent potential of the current knowledge base with
an emphasis upon cocrystallization and the desire for scientific exploration that will lead
to the development of a future generation of novel cocrystals. The focus of this
dissertation is to expand the cocrystallization knowledge base in two directions with the
utilization of cocrystals in the novel synthetic technique of cocrystal controlled solid-state
synthesis and in the development of active pharmaceutical ingredients.
Cocrystal controlled solid-state synthesis uses a cocrystal to align the reactive
moieties in such a way that the reaction occurs more quickly and in higher yield than the
typical solution methodology. The focus herein is upon cocrystal controlled solid-state
synthesis of imides where an anhydride and primary amine were the reactive moieties.
Forty-nine reactions were attempted and thirty-two resulted in successful imide
formation. In addition, the cocrystal was isolated as part of the reaction pathway in three
cases and is described in detail.
The impact of cocrystals upon active pharmaceutical ingredients is also addressed
with a focus upon generating novel crystal forms of lamotrigine and meloxicam.
Cocrystallization attempts of lamotrigine resulted in ten novel crystal forms including
three cocrystals, one cocrystal solvate, three salts, one solvated salt, a methanol solvate,
and an ethanol hydrate. Additionally, cocrystallization attempts of meloxicam afforded
seven novel cocrystals. Solubility and pharmacokinetic studies were conducted for a
selected set of lamotrigine and meloxicam crystal forms to determine the crystal form
with the most desirable properties. Properties between crystal form and cocrystal former
were also examined.
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Kingsley, Nickolas Dana. "Development of Miniature, Multilayer, Integrated, Reconfigurable RF MEMS Communication Module on Liquid Crystal Polymer (LCP) Substrate." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/14547.
Full textAbstract:
For this thesis, the use of Liquid Crystal Polymer (LCP) as a system-level substrate and packaging material is investigated. Early in the research, recipes for fabricating on LCP were developed. With this knowledge, RF components were able to be fabricated. These devices include filters, antennas, phase shifters, and RF MEMS switches.
To investigate the potential of using LCP as a system-level material, packaging properties and robustness were tested. This research demonstrated that LCP could be used to package something as small and delicate as an individual switch or as large as a 4-inch wafer. In addition, it was shown that MEMS switches could survive well over a hundred million cycles. This demonstrated that LCP could be used to create reliable, high performance systems.
The culmination of this research was used to create two variations of a communication module. The first device was fabricated on one layer and a multi-layer approach was taken for the other device. These modules needed to be low-cost, low-loss, flexible, and capable of beam steering. This technology can be used for communication, sensing, detection, and surveillance for a broad scope of applications. To this date, they are by far the most sophisticated SOP on LCP ever achieved. This technology can be further developed to include more functionality, smaller size, and even better performance.
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Taushanoff, Stefanie. "Development and Characterization of Blue Phases Made From Bent-Core Liquid Crystals." Kent State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=kent1298650764.
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Ma, Qingjun. "Crystal structure of wind, a PDI-related protein required for Drosophila melanogaster dorsal-ventral development." [S.l.] : [s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=970195044.
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Elsom, Jacqueline. "Development of a quartz crystal based biosensor for real-time monitoring of particulate cell interactions." Thesis, University of Brighton, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.412096.
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MOREIRA, MICHELE FIGUEIREDO. "DEVELOPMENT AND CHARACTERIZATION OF A CHOLESTERIC LIQUID CRYSTAL LASER SYSTEM COUPLED TO AN OPTICAL FIBER." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2004. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=5261@1.
Full textAbstract:
CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICONeste trabalho estudamos a viabilidade do desenvolvimento de um sistema laser de cristal líquido colestérico (CLC) acoplado a fibra óptica visando sua aplicação como um sensor de temperatura. Sensores laser de CLC acoplados a fibra óptica são atrativos devido às enormes vantagens que as fibras ópticas apresentam e à resposta de cristais líquidos a vários estímulos externos. A emissão laser de CLC ocorre na banda de menor energia da banda de reflexão, e corresponde a um comprimento de onda determinado pelo passo e pelo índice de refração extraordinário. Esses parâmetros podem ser alterados pela mudança da temperatura externa, proporcionando variações no comprimento de onda do laser de CLC. Essas variações no comprimento de onda do laser de CLC podem ser usadas para monitorar a temperatura. Obtivemos emissão laser estável num sistema laser CLC acoplado à fibra óptica quando bombeado pelo segundo harmônico de um laser de Nd:YAG e desenvolvemos uma técnica para ancorar o cristal líquido nas extremidades das fibras ópticas. A dependência da emissão laser com a temperatura foi investigada em duas situações, posicionando o laser de CLC entre fibras ópticas e em células de vidro. Diversos cristais líquidos foram estudados a fim de se otimizar a resposta do laser com a temperatura. Variações discretas na dependência do comprimento de onda da emissão laser foram observadas no sistema que utilizava as células de vidro. Associamos esse comportamento à dependência do ancoramento das moléculas do cristal líquido na superfície do vidro com a temperatura.
In this work, we have studied the viability of developing a cholesteric liquid crystal (CLC) laser system coupled into an optical fiber aiming its application as temperature sensor. Sensors made of CLC laser coupled to optical fibers are a very attractive proposition due to the enormous advantages of the optical fibers and the response of the liquid crystal to various external stimuli. The laser emission occurs at the low energy edge of the reflection band, and the corresponding wavelength is determined by the pitch and the extraordinary refractive index. These parameters can be altered by a change in the external temperature, leading to variations in the wavelength of the CLC laser emission, which can be used to monitor the external temperature. We obtained a stable laser emission in a CLC laser system coupled into an optical fiber when pumped by the second harmonic of a Nd:YAG laser. A technique to anchor the liquid crystal at the optical fibers ends was developed. The temperature dependence of the laser emission was investigated in two situations, placing the CLC laser between optical fibers and into the glass cells. Several liquid crystals were studied in order to optimize the laser response with temperature. Discrete variations in the temperature dependence of the laser emission wavelength were observed when the glass cell system was used. We associated this behavior to a temperature dependence of the surface anchoring of the liquid crystal molecules in the glass surface.
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Bonoan, Janpierre A. "Development and characterization of a novel drug dissolution test method using a quartz crystal microbalance." Scholarly Commons, 2015. https://scholarlycommons.pacific.edu/uop_etds/217.
Full textAbstract:
Current dissolution apparatuses require several hundred milligrams of sample per trial, measure dissolution rate indirectly via concentration sampling, and cannot maintain sink conditions throughout the duration of a test. This work describes a novel dissolution testing methodology developed using a commercial quartz crystal microbalance (QCM) system to measure dissolution rates of drugs while overcoming the limitations of current dissolution methods. The apparatus was characterized for a sample drug system of benzoic acid dissolved using a dissolution medium of deionized water at flow rates of 1000, 100, 50, and 10 &mgr;L/min. Using an analysis method that combines the responses of resonance frequency and resistance of the quartz crystal during dissolution, the dissolution rate of benzoic acid was found to be 4.029 ± 0.743, 2.026 ± 0.913, 1.565 ± 0.349, and 1.060 ± 0.103 % mass/s, for each flow rate, respectively. The QCM dissolution apparatus method can be used to measure drug dissolution directly by quantifying mass loss (rather than indirectly via concentration changes as with current methods), reduce sample sizes compared with current methods by three orders of magnitude onto the microgram scale, and maintain sink conditions throughout the duration of the test.
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Van, der Werff Matthew John. "Development of digital instrumentation for bond rupture detection : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Engineering at Massey University, Palmerston North, New Zealand." Massey University, 2009. http://hdl.handle.net/10179/857.
Full textAbstract:
In the medical world the precise identification of a disease can take longer than it is safe to wait to start treatment so there is a need for faster and more precise biosensors. Bond Rupture is a new sensor technique that maybe able to improve disease detection. It does this by inducing bonds to rupture from the surface, and also measuring the point at which this rupture occurs this enables the forces to be measured on the surface. Specifically, this project has focused on the application of Bond Rupture to detecting antigens when bound to a surface using their specific antibodies, and the idea that the rupture force of these antigens can also be measured. The sensor that this project is based around is the Quartz Crystal Microbalance (QCM), which oscillates horizontally when a voltage is applied, and can also be used to measure mass change on its surface via change in resonant frequency. The aim of this project was to investigate possible Bond Rupture detection methods and techniques and has involved the development of a high speed digital electronics system, for the purposes of inducing and detecting Bond Rupture. This has involved the development of a FPGA based high speed transceiver board which is controlled by a Digital Signal Processor (DSP), as well as the development of various graphical user interfaces for end user interaction. Bond rupture testing was carried out by rupturing beads from the surface of a QCM in an experiment taking as little as 20 seconds. The Bond Rupture effect has been observed via the high accuracy measurement of the frequency change while inducing Bond Rupture on the sensor, proving that the Bond Rupture effect indeed exists. The research performed is believed to be a world first in terms of the method used and accuracy acquired.
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黃玉欣 and Yuk-yan Wong. "Development of piezoelectric crystal detectors for sensing bacteria inwater and determining volatile organic compounds in air." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2000. http://hub.hku.hk/bib/B43894215.
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McMillan, Alex. "Development of an all-fibre source of heralded single photons." Thesis, University of Bath, 2012. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.557827.
Full textAbstract:
The preparation of single photons in a pure quantum state is a subject of great interest in physics, enabling the control of light at an unprecedented level. The ease with which certain degrees of freedom of photon states, such as polarisation, can be manipulated, along with the inherent resilience of photons to decoherence, makes them well suited for use as qubits. Recent rapid developments in the transmission and processing of quantum information, as well as the likely technological impact of potential real-world applications such as quantum cryptography and quantum computation, mean that the demand for high performance single photon sources is likely to increase in the near future. One approach to producing single photon states, which are known to be in a well-defined spatio-temporal mode without destructively measuring them, is to take advantage of nonlinear optics. Nonlinear processes can be used to realise frequency conversion by generating a single, correlated pair of photons from an intense pump laser source. The detection of one of the photons from a pair can then be used to indicate the presence of the other photon in the pair, a procedure known as heralding. This thesis describes the development of a source of heralded single photons at 1550 nm, generated directly in the core of a photonic crystal fibre (PCF). By taking advantage of low loss fibre components for the required spectral filtering of the generated photon state, a heralding fidelity of 52% was achieved. The source was designed to be used with a picosecond pulsed fibre laser, making it relatively low cost and maintenance free. With 148 mW of average pump power a heralded output photon rate of 6.4 × 104 s-1 was observed, demonstrating the brightness of the source. The purity of the generated single photons was established by measuring non-classical interference, with a visibility of 70%, between the photons output from this source and a source based on a PPLN waveguide. The fabrication of a series of birefringent PCFs for the generation of spectrally pure state photons at 1550 nm is also discussed. These PCFs will be useful for incorporation in the next generation of high performance, fibre-based photon sources.
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Bairavasubramanian, Ramanan. "Development of microwave/millimeter-wave antennas and passive components on multilayer liquid crystal polymer (LCP) technology." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/14546.
Full textAbstract:
The investigation of liquid crystal polymer (LCP) technology to function as a low-cost next-generation organic platform for designs up to millimeter-wave frequencies has been performed.
Prior to this research, the electrical performance of LCP had been characterized only with the implementation of standard transmission lines and resonators. In this research, a wide
variety of passive functions have been developed on LCP technology and characterized for the first time. Specifically, we present the development of patch antenna arrays for remote sensing applications, the performance of compact low-pass and band-pass filters up to millimeter-wave frequencies, and the integration of passive elements for X-band and V-band transceiver systems.
First, dual-frequency/dual-polarization antenna arrays have been developed on multilayer LCP technology and have been integrated with micro-electro-mechanical-system (MEMS) switches to achieve real-time polarization reconfigurability. These arrays are conformal, efficient and have all the features desirable for
applications that require space deployment.
Second, a wide variety of filters with different physical and functional characteristics have been implemented on both single and multilayer LCP technology. These filters can be classified
based on the filter type (low-pass/band-pass), the resonators used (single-mode/dual-mode), the response characteristics (symmetric/asymmetric), and the structure of the filter (modular/non-modular).
Last, examples of integrated modules for use in transceiver systems are presented. This part of the research involves the development of duplexers, radiating elements, as well as their
integration. The duplexers themselves are realized by integrating a set of band-pass filters and matching networks. The characterization of the individual components, and of the integrated system are included.
This research has resulted in a thorough understanding of LCP's electrical performance and its multilayer lamination capabilities pertaining to its functioning as a material platform for
integrated microwave systems. Novel passive prototypes that can take advantage of such multilayer capabilities have been developed.
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Mcnamara, Thomas. "Analysis and metric development for the study of viscoelastic thin films utilising a quartz crystal microbalance." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/analysis-and-metric-development-for-the-study-of-viscoelastic-thin-films-utilising-a-quartz-crystal-microbalance(b82fec4b-728d-43e6-842b-0941f21be200).html.
Full textAbstract:
The aim of this thesis is the creation of a set of tools for the quartz crystal microbalance (QCM-D) that aid in the measurement and quantification of soft viscoelastic thin films and experimental work demonstrating their use. The QCM-D is an acoustic technique that monitors structural changes occurring at the sensor's surface via changes in the sensor's resonance frequency and the rate of mechanical energy loss (dissipation). As a first approximation, the frequency shifts are used to measure mass changes on the sensor's surface, and dissipation shifts used to quantify changes in the rigidity of the film. Use of the QCM-D responses in this manner requires that the film is acoustically thin and rigid, limiting its application to soft films. To quantify mass and viscoelastic changes using the QCM-D, soft films either need to be approximated to a thin, rigid layer, or the frequency and dissipation responses modelled using a viscoelastic model. Such an approximation leads to the encompassment of all the viscoelastic properties into the single dissipation measurement in addition to potentially introducing errors in mass calculations. Existing commercial software allows for the deconvolution of film parameters such as the shear modulus and viscosity by fitting experimental data to a viscoelastic model. This analysis can only be done after the experimental data is collected however, and provides no guidance on future experiments, also commonly requiring an initial estimate of the parameter values under investigation. I have developed an experimental optimisation tool, termed the total parameter matrix sensitivity (TPM-sensitivity). It is defined as the Jacobian determinant of the QCM-D responses with respect to the parameters under investigation, e.g. the film's height, density, viscosity and shear modulus and the bulk fluid's density and viscosity. TPM-sensitivity is a measure of how readily resolvable and separable the film and bulk are when analysing the QCM-D responses. This enables the user to select the most mathematically important harmonics, and using this I was able to experimentally resolve the viscoelastic information of a soft film using frequency responses alone. I have also defined a classification system which categorises the QCM-D responses relative to a perfectly rigid and thin film. This provides guidance on the level of analysis required to gain information about the film parameters, with the limitations of commonly applied rules of thumb also demonstrated. Examples using these computational tools and metrics are also presented with data I obtained experimentally and from the literature. Of the experimental investigations, the curing process of a bulk elastomer is of particular importance due to the film being both soft and acoustically thick, demonstrating QCM-D use for a film not complying to either of thecommonly used film approximations.
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Fearon, Shelley Helen. "The Development of an African Horse Sickness Virus VP7 Quasi-Crystal Vaccine Candidate in N. benthamiana." Master's thesis, Faculty of Science, 2019. https://hdl.handle.net/11427/31671.
Full textAbstract:
African horse sickness (AHS) is a debilitating viral disease affecting equines and has resulted in many disastrous epizootics. To date, no successful therapeutic treatment exists for AHS and the commercially used live-attenuated vaccines (LAVs) have various side effects. Insoluble particulates have been shown to increase immunogenicity when compared to soluble subunit vaccines and previous studies demonstrated protection of BALB/c mice immunised with African horse sickness virus (AHSV) VP7 against a lethal challenge of AHSV-7 (Bailey 2016; Rutkowska et al. 2011; St Clair et al. 1999; Storni et al. 2005; Wade-Evans et al. 1997). This study investigates a safer monovalent vaccine alternative based on plant-produced quasicrystals of the serogroup-specific AHSV structural protein, VP7. AHSV serotype 5 (AHSV-5) VP7 was expressed in Nicotiana benthamiana by means of Agrobacterium-mediated infiltration of plant expression vector pRIC3.0 encoding VP7 and quasi-crystals purified by means of density gradient ultracentrifugation. The presence of AHSV VP7 quasi-crystals was confirmed by western immunoblotting with anti-AHSV VLP guinea-pig serum and characterized using transmission electron microscopy. After optimizing the purification protocol and achieving satisfactory concentrations, AHSV-5 VP7 quasi-crystals were used in guinea-pig immunogenicity studies where the experimental group (n=5) was inoculated with prime- and boostinoculations of between 10 and 50 µg of purified AHSV VP7 quasi-crystals, and the control group (n=5) inoculated with a control inoculum prepared in the identical manner as the vaccine but using a pRIC3.0 expression vector lacking VP7. Western immunoblot analysis of the humoral response showed stimulation of very high titres of anti-VP7 antibodies 28 days after the boost-inoculation. In addition, RNA-seq transcriptome profiling of guinea-pig spleen derived RNA was used to investigate the global immune response to AHSV-5 VP7 quasi-crystals. Thirty genes involved in innate and adaptive immunity were found to be significantly differentially expressed (q≤0.05) in experimental transcriptome data when compared to the control. Differential expression of genes involved in T-helper (Th)1, Th2 and Th17 cell differentiation and the T-cell receptor signalling pathway suggest a possible cell-mediated immune response to AHSV-5 VP7 quasi-crystals. Upregulation of several important cytokines and cytokine receptors were noted in response to VP7 quasi-crystals e.g. TNFSF14, CX3CR1, IFNLR1 and IL17RA. TNFSF14 and CX3CR1 play a role in T-cell proliferation and cytotoxic T-cell responses respectively. And IFNLR1 and IL17RA are key cytokines in antiviral defences. Upregulation of IL17RA suggests a Th17 response which has been reported as a key component in AHSV immunity. To the best of our knowledge, this study is the first to report the expression of plantproduced AHSV VP7 quasi-crystals and the first time that the cell-mediated immune response to these particles has been assessed. While further investigation is needed, these results suggest that AHSV-5 VP7 quasi-crystals produced in N. benthamiana are immunogenic, inducing both humoral and cell-mediated responses.
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Wahl, Helene. "Development of novel supramolecular framework materials based on organic salts." Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/95858.
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Thesis (PhD)--Stellenbosch University, 2014.ENGLISH ABSTRACT: The aim of the work presented in this thesis was to design ionic organic framework materials based on carboxylate salts with the intention of engineering interesting properties, such as porosity, into these framework materials. The first section focuses on the characterisation and porosity studies of an ionic framework material, 3,4-lutidinium pamoate hemihydrate, with THF-filled channels in the solid state. It was shown that this framework is able to exchange the THF in the channels for a wide variety of compounds, with many of these exchanges occurring in a single-crystal to single-crystal fashion. Competition experiments conducted with the framework, both by immersing crystals of the framework in solvent mixtures, as well as by exposing crystals of the framework to mixtures of solvent vapours, indicated that it is able to selectively exchange for one guest over another. The kinetics of exchange of this framework were studied, and it was possible to identify a kinetic model describing this process. A second novel framework-type material, 4-phenylpyridinium pamoate, was identified during the course of this study, as well as five isostructural frameworks containing different guest molecules. In this case the framework consists of discrete units that close-pack in such a way that guest molecules are included in constricted cavities in the solid state. Although this framework-type material is not porous, it is thermally quite stable and also highly selective. It is able to selectively encapsulate 1,4-dioxane when crystallised from various solvent combinations including 1,4-dioxane. In addition, eight novel structures with pamoic acid in combination with various pyridyl derivatives were obtained. A third novel framework material was obtained with N,N'-bis(glycinyl)pyromellitic diimide in which, due to the extended hydrogen-bonded network formed between the constituents of the framework, DMF molecules are aligned in channels. It was found that this framework material can also be formed by mechanochemical synthesis, and investigation of the thermal behaviour of this framework showed that it has the potential to be porous, since the framework appears to remain intact after desolvation. Furthermore, six novel structures with N,N'- bis(glycinyl)pyromellitic diimide in combination with various N-heterocycles were obtained. All structures obtained in this study were also further analysed to determine whether there are particular structural features that are required for framework formation. Insights gained from these investigations, in terms of degree of ionisation of the anion, packing arrangements and hydrogen bonding patterns as well as the molecular shape of the components are discussed.
AFRIKAANSE OPSOMMING: Die doel van die werk wat in hierdie tesis voorgelê word is om ioniese organiese raamwerkmateriale gebaseer op karboksilaatione te ontwerp, met die voorneme om interessante eienskappe in hierdie materiale te bewerkstellig. Die eerste afdeling fokus op die karakterisering en porositeit van ‘n ioniese organiese raamwerkmateriaal, 3,4-lutidiniumpamoaathemihidraat, wat kanale gevul met tetrahidrofuraan (THF) besit. Dit is aangetoon dat dit moontlik is vir hierdie raamwerkmateriaal om die THF in die kanale te verruil vir ‘n wye verskeidenheid stowwe, waarvan baie van hierdie uitruilings geskied as ‘n enkelkristal tot enkelkristal transformasie. Kompetisie-eksperimente is met hierdie raamwerkmateriaal uitgevoer deur die kristalle in mengsels van oplosmiddels te onderdompel, sowel as deur die kristalle aan mengsels van die oplosmiddeldampe bloot te stel. Die resultate het aangedui dat dit moontlik is vir hierdie raamwerkmateriaal om een gasstof selektief teenoor ‘n ander te verruil vir die THF in die kanale. Die kinetika van die uitruilingsproses van hierdie materiaal is ook bestudeer en dit was moontlik om ‘n kinetiese model te identifiseer wat die uitruilingsproses beskryf. ‘n Tweede nuwe raamwerk-tipe materiaal, 4-fenielpiridiniumpamoaat, is deur die loop van hierdie studie geïdentifiseer, sowel as vyf isostrukturele raamwerkmateriale waarvan net die gasstof verskil. In hierdie geval bestaan die raamwerk uit diskrete eenhede wat op so ‘n wyse saampak dat die gasstowwe in vernoude porieë ingesluit word. Alhoewel hierdie raamwerk-tipe materiaal nie poreus is nie, is dit termies stabiel en ook hoogs selektief. Die raamwerkmateriaal kan selektief 1,4-dioksaan enkapsuleer wanneer dit gekristalliseer word vanuit ‘n verskeidenheid oplosmiddel kombinasies met 1,4-dioksaan. Verder is agt nuwe strukture verkry met die pamoaat ioon in kombinasie met ‘n verskeidenheid piridien-derivate. ‘n Derde nuwe raamwerkmateriaal is verkry met N,N'-bis(glisiniel)piromellitiese diïmied waarin, danksy die uitgebreide waterstofgebinde netwerk tussen die komponente van die raamwerk, die DMF molekules in kanale aangetref word. Hierdie raamwerkmateriaal kan deur meganochemiese sintese berei word en verdere ondersoek na die termiese gedrag van hierdie raamwerkmateriaal dui aan dat dit die potensiaal het om porositeit te toon, aangesien die raamwerk behoue bly nadat die DMF molekules verwyder is. Ses nuwe strukture is ook met N,N'-bis(glisiniel)piromellitiese diïmied in kombinasie met ‘n wye verskeidenheid stikstof-bevattende heterosikliese verbindings verkry. Alle strukture wat tydens hierdie studie verkry is, is verder ondersoek om te bepaal of daar spesifieke strukturele kenmerke is wat benodig word vir die vorming van raamwerkmateriale. Insigte wat verkry is vanuit hierdie ondersoeke, in terme van die graad van ionisasie van die anioon, die rangskikking van molekules in die struktuur en waterstofbindingspatrone, sowel as die molekulêre vorm van die komponente, word bespreek.
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Wong, Yuk-yan. "Development of piezoelectric crystal detectors for sensing bacteria in water and determining volatile organic compounds in air." Hong Kong : University of Hong Kong, 2000. http://sunzi.lib.hku.hk/hkuto/record.jsp?B22330860.
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Ozcan, Orhan. "Medium Development For Production Of Bacillus Thuringiensis Based Biopesticides." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/3/12609285/index.pdf.
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The insect pathogen Bacillus thuringiensis (Bt) holds great promise as an effective and friendly way for management of the pests with safety for nontarget animals and humans. However, high capital investment due to high production and formulation cost of commercial Bt preparations has caused prohibitive effect on companies. The present study mainly aimed at developing a low cost medium that supports the growth of different Bt strains and their specific bioinsecticidal δ
-endotoxins (crystal proteins). A comparison was made between the representative members of three different subspecies of Bt to observe toxin yields in response to certain nutritional conditions. Three different Bt subspecies were Bt kurstaki (strain 81), Bt israelensis (strain HD500) and Bt tenebrionis (strain 3203), producing lepidoptera- and diptera-specific Cry1 and Cry2, diptera-specific Cry4Ba and Cry11Aa and coleoptera-specific Cry3Aa toxins, respectively. Studies were conducted to optimize glucose and inorganic phosphate concentrations in standard DSM medium for the production of these Bt-based biopesticides. General suppression of toxin yields in high glucose medium (10 g/L) thought the generality of carbon catabolite regulation for biosynthesis of different types of toxins. Inorganic phosphate (Pi) level was important for Cry4Ba, Cry11Aa and Cry3Aa biosynthesis while Cry1 and Cry2 production was not responsive to high Pi. Wastewater sludge, fruit residues and broiler litter were next tested as cheap raw materials for Bt-based biopesticide production in batch cultures. Broiler litter seemed to be a much better substrate among all since some degree of production of each toxin was observed at almost every stage of fermentation. The processing of broiler litter was found to significantly improve toxin yields. The medium prepared from processed broiler litter was successfully used to cultivate all Bt stains and obtain bioinsecticidal proteins in high yields which were comparable or higher than those that can be obtained on standard semi-synthetic media.
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Medendorp, Clare Aubrey. "ATOMIC FORCE MICROSCOPY METHOD DEVELOPMENT FOR SURFACE ENERGY ANALYSIS." UKnowledge, 2011. http://uknowledge.uky.edu/gradschool_diss/185.
Full textAbstract:
The vast majority of pharmaceutical drug products are developed, manufactured, and delivered in the solid-state where the active pharmaceutical ingredient (API) is crystalline. With the potential to exist as polymorphs, salts, hydrates, solvates, and cocrystals, each with their own unique associated physicochemical properties, crystals and their forms directly influence bioavailability and manufacturability of the final drug product. Understanding and controlling the crystalline form of the API throughout the drug development process is absolutely critical. Interfacial properties, such as surface energy, define the interactions between two materials in contact. For crystal growth, surface energy between crystal surfaces and liquid environments not only determines the growth kinetics and morphology, but also plays a substantial role in controlling the development of the internal structure. Surface energy also influences the macroscopic particle interactions and mechanical behaviors that govern particle flow, blending, compression, and compaction. While conventional methods for surface energy measurements, such as contact angle and inverse gas chromatography, are increasingly employed, their limitations have necessitated the exploration of alternative tools. For that reason, the first goal of this research was to serve as an analytical method development report for atomic force microscopy and determine its viability as an alternative approach to standard methods of analysis. The second goal of this research was to assess whether the physical and the mathematical models developed on the reference surfaces such as mica or graphite could be extended to organic crystal surfaces. This dissertation, while dependent upon the requisite number of mathematical assumptions, tightly controlled experiments, and environmental conditions, will nonetheless help to bridge the division between lab-bench theory and successful industrial implementation. In current practice, much of pharmaceutical formulation development relies on trial and error and/or duplication of historical methods. With a firm fundamental understanding of surface energetics, pharmaceutical scientists will be armed with the knowledge required to more effectively estimate, predict, and control the physical behaviors of their final drug products.