Dissertations / Theses on the topic 'Additivity of the Effects'
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Oicherman, Boris. "Effects of colorimetric additivity failure and of observer metamerism on cross-media colour matching." Thesis, University of Leeds, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.441230.
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Chiu, Hsiang-Chih. "Demostration of non-additivity ans asymmetry in the lateral Casimir force." Diss., UC access only, 2009. http://proquest.umi.com/pqdweb?index=41&did=1905738741&SrchMode=1&sid=2&Fmt=7&retrieveGroup=0&VType=PQD&VInst=PROD&RQT=309&VName=PQD&TS=1270142776&clientId=48051.
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Thesis (Ph. D.)--University of California, Riverside, 2009.Includes abstract. Includes bibliographical references (leaves 146-154). Issued in print and online. Available via ProQuest Digital Dissertations.
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Rasch, Dieter, Thomas Rusch, Marie Simeckova, Klaus D. Kubinger, Karl Moder, and Petr Simecek. "Tests of additivity in mixed and fixed effect two-way ANOVA models with single sub-class numbers." Springer, 2009. http://dx.doi.org/10.1070/s00362-009-0254-4.
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In variety testing as well as in psychological assessment, the situation occurs that in a
two-way ANOVA-type model with only one replication per cell, analysis is done under
the assumption of no interaction between the two factors. Tests for this situation are
known only for fixed factors and normally distributed outcomes. In the following we will
present five additivity tests and apply them to fixed and mixed models and to quantitative
as well as to Bernoulli distributed data. We consider their performance via simulation
studies with respect to the type-I-risk and power. Furthermore, two new approaches
will be presented, one being a modification of Tukey's test and the other being a new
experimental design to test for interactions.
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Bogen, Daniel J. "Effects of Manufacturing Defects on the Corrosion of Additively Manufactured AlSi10Mg." Youngstown State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1596641889374996.
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Whatcott, Tyler Blaine. "Effects of Conformal Cooling Channels on Additively Manufactured Injection Molding Tooling." BYU ScholarsArchive, 2020. https://scholarsarchive.byu.edu/etd/8727.
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This study focuses on the cycle-averaged mold temperature of additively manufactured injection molding tooling and how it is affected by conformal cooling channels. This was done by producing a benchmark mold out of Digital ABS produced by Stratasys, an acrylic based photopolymer, which was then used to produce injection molded parts until tool failure. Another, more cost-effective material, High Temp Resin produced by Formlabs, another acrylic based photopolymer, was also tested but yielded very little success. Then the mold design was altered by adding conformal cooling channels and again tested by producing injection molded parts while tracking the mold temperature. This experimentation was then compared to an injection molding cooling channel model in order to validate the model for use with additively manufactured tooling with conformal cooling channels for use in injection molding. The benchmark Digital ABS mold was able to produce 66 shots in the injection molding machine before complete mold failure. The Digital ABS mold had a cycle-averaged mold temperature of about 155°F. The High Temp Resin mold was able to produce 3 shots before complete mold failure. The High Temp Resin material is much more brittle, and the mold design did not take into account how brittle the material was. The Digital ABS mold with conformal cooling channels had a cycle-averaged mold temperature of 111°F. This is significantly lower than without cooling channels and has a high potential for improving tooling life. The cooling channel model predicted the cycle-averaged mold temperature to be 116°F. This proved to be a very good model and can be used as a design tool when choosing cooling channel geometry and position in additively manufactured tooling. This research shows the potential that conformal cooling channels have to help improve additively manufactured tooling life for injection molding. As shown in other research done, the ability to maintain the mold below 120°F significantly improves the life of additively manufactured tooling. The results of this study demonstrate the effectiveness of conformal cooling channels in controlling mold temperature. It should be researched further, but the use of conformal cooling channels has the potential to produce more production or prototype parts with additively manufactured tooling for injection molding.
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Booysen, Theo-Neal. "Microstructural effects on properties of additively manufactured Inconel 625 and 718." Thesis, Cape Peninsula University of Technology, 2019. http://hdl.handle.net/20.500.11838/3043.
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Thesis (MEng (Mechanical Engineering))--Cape Peninsula University of Technology, 2019Three Dimensional(3D) printing is known as additive manufacturing: it is a method of manufacturing parts or components form sheet, wire or powder in a manufacturing process. This method differs from traditional manufacturing techniques such as casting, moulding or subtracting materials which already exist. The type of material characterization is also very important in the development and improve or manufacturing of new materials for higher strength and various application. Selective Laser Melting(SLM) an additive manufacturing powder-based process has been adopted by automotive and aerospace industries. The reason for this is that it has many potential benefits, such as 3D designs of complex components in a shortened time frame, which offers financial savings. SLM process use metallic powders with different chemical composition to manufacture complex structures, which is an innovative material processing technology. In this research SLM, a typical additive manufacture process method, was used to manufacture additively manufactured Inconel 625 and 718. These sample specimens were investigated to determine their microstructural features and mechanical properties. The microstructural features were characterized using two different experimental surface microscopy methods: scanning electron microscope(SEM) and light optical microscope (LOM). The mechanical properties were determined by studying deformation and hardness characteristics using three-point bending and hardness tests. The relationship between processing, microstructure, grain sizes and mechanical properties was established. The understanding of SLM additive manufacturing of alloys is important as well for the adoption of the technology, and the possibility of replacing commercially produced cast and wrought alloys in the near future.
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Yamanaka, Hajime. "The Effects of Weld Thermal Cycles on Additively Manufactured 316L Stainless Steel." DigitalCommons@CalPoly, 2019. https://digitalcommons.calpoly.edu/theses/2029.
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To address the size limitation of the powder bed fusion system in additive manufacturing, the welding properties of 316L stainless steel manufactured by SLM 125HL are investigated by conducting hot ductility test and nil strength temperature (NST) test with a physical thermal mechanical simulator, Gleeble. In this study, the print orientations (Zdirection and XY-direction) and the laser patterns (stripe and checker board) are studied. In NST test, the orientation showed a statistical significance in NST: Z-direction was 1384°C and XY-direction was 1400°C. In hot ductility test, all of ductility curves show similar behaviors: hardening region, recrystallization region, and liquation region. The additively manufactured 316L shows poor ductility compared to wrought 316L stainless steel. Also, there is a noticeable difference in ductility between laser pattern. Finally, ductility after the thermal cycle shows higher than that before the thermal cycle. For the future recommendation, investigation on the interelayer temperatures and sigma phase determination should be conducted to confirm the hypotheses to explain the phenomena observed in this study.
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Yegyan, Kumar Ashwath. "Effects of Hot Isostatic Pressing on Copper Parts Additively Manufactured via Binder Jetting." Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/82833.
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Copper is a material of interest to Additive Manufacturing (AM) owing to its outstanding material properties, which finds use in enhanced heat transfer and electronics applications. Its high thermal conductivity and reflectivity cause challenges in the use of Powder Bed Fusion AM systems that involve supplying high-energy lasers or electron beams. This makes Binder Jetting a better alternative as it separates part creation (binding together of powders) from energy supply (post-process sintering). However, it is challenging to fabricate parts of high density using this method due to low packing density of powder while printing. This work aims to investigate the effects of Hot Isostatic Pressing (HIP) as a secondary post-processing step on the densification of Binder Jet copper parts. By understanding the effects of HIP, the author attempts to create parts of near-full density, and subsequently to quantify the effects of the developed process chain on the material properties of resultant copper parts. The goal is to be able to print parts of desired properties suited to particular applications through control of the processing conditions, and hence the porosity. First, 99.47% dense copper was fabricated using optimized powder configurations and process parameters. Further, the HIP of parts sintered to three densities using different powder configurations was shown to result in an improvement in strength and ductility with porosity in spite of grain coarsening. The strength, ductility, thermal and electrical conductivity were then compared to various physical and empirical models in the literature to develop an understanding of the process-property-performance relationship.Master of Science
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Dunn, Martin A. "A numerical & experimental investigation into size effects within loaded additively manufactured cellular solids." Thesis, University of Strathclyde, 2018. http://digitool.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=30531.
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The behaviour of heterogeneous materials when loaded cannot be adequately described by classical elasticity as it doesn’t account for the presence of internal length-scales. Higher order theories such as micropolar elasticity may be more appropriate, though the additional elastic constants required to fully describe such materials are hard to identify experimentally. In micropolar theory a size effect is predicted in bending and torsion which is revealed as an increase in relative stiffness with decreasing size at scales approaching the cellular microstructure. Thus, at the microstructural level, size and scale becomes an important consideration. Hence, materials which appear homogeneous at a large scale may be heterogeneous at smaller scales when overall size approaches that of the cellular structure. Addressing this issue requires aclear understanding of how scale influences the material’s mechanical properties. Here, the mechanical response of periodic, cellular lattices has been explored within the context of micropolar theory by conducting discrete numerical simulations and experimental tests. It will be shown that the size effects displayed in bending and torsion are strongly dependent on the cellular volume fraction and sample section second moment of area associated with the distribution of the matrix material within the cells comprising the section. Crucially however, these effects may be masked by surface texture and localised loading conditions. Despite the inherent difficulties associated with experimental testing, the size effects which are predicted by micropolar theory are identified experimentally in an additively manufactured cellular material. The observed size effects showed reasonable agreement to numerical simulations performed in ANSYS. Demonstrating that the behaviour of structured cellular materials with deterministic properties, fabricated by additive manufacturing, can be described by more generalised deformation theories is important as it enables the design and development of new and novel materials to be explored and exploited in lightweight structural applications.
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Forsberg, Simon. "Complex Trait Genetics : Beyond Additivity." Doctoral thesis, Uppsala universitet, Institutionen för medicinsk biokemi och mikrobiologi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-307837.
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The link between the genotype and the phenotype of an organism is immensely complex. Despite this it can, to a great extent, be captured using models that assume that gene variants combine their effects in an additive manner. This thesis explores aspects of genetics that cannot be fully captured using such additive models. Using experimental data from three different model organisms, I study two phenomena that fall outside of the additive paradigm: genetic interactions and genetic variance heterogeneity. Using the model plant Arabidopsis thaliana, we show how important biological insights can be reached by exploring loci that display genetic variance heterogeneity. In the first study, this approach identified alleles in the gene CMT2 associated with the climate at sampling locations, suggesting a role in climate adaption. These alleles affected the genome wide methylation pattern, and a complete knock down of this gene increased the plants heat tolerance. In the second study, we demonstrate how the observed genetic variance heterogeneity was the result of the partial linkage of many functional alleles near the gene MOT1, all contributing to Molybdenum levels in the leaves. Further, we explore genetic interactions using data from dogs and budding yeast (Saccharomyces cerevisiae). In the dog population, two interacting loci were associated with fructosamine levels, a biomarker used to monitor blood glucose. One of the loci displayed the pattern of a selective sweep in some of the studied breeds, suggesting that the interaction is important for the phenotypic breed-differences. In a cross between two strains of yeast, with the advantage of large population size and nearly equal allele frequencies, we identified large epistatic networks. The networks were largely centered on a number of hub-loci and altogether involved hundreds of genetic interactions. Most network hubs had the ability to either suppress or uncover the phenotypic effects of other loci. Many multi-locus allele combinations resulted in phenotypes that deviated significantly from the expectations, had the loci acted in an additive manner. Critically, this thesis demonstrates that non-additive genetic mechanisms often need to be considered in order to fully understand the genetics of complex traits.
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Ngo, Austin. "Effects of Build Orientation and Post Processing on the Mechanical Properties of Additively Manufactured AlSi10Mg." Case Western Reserve University School of Graduate Studies / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=case1588623582368507.
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Merkley, Stephen L. "Effects of Radiation Heating on Additively Printed Hybrid Fuel Grain Oxidizer-to-fuel Ratio Shift." DigitalCommons@USU, 2016. https://digitalcommons.usu.edu/etd/5230.
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This thesis examined the hypothesis that radiative heat transfer in small-scale printed-fuel hybrid rocket motors is responsible for the observed decreasing oxidizer-to-fuel (O/F) ratio shift. The magnitude of the radiation term was negligible for the motor sizes and types of propellants that have been previously tested, but was reintroduced in this study. To prove this hypothesis, a detailed enthalpy balance model was developed and tested using experimental fuel regression rate data obtained from a variety of motor scales using additively-manufactured acrylonitrile butadiene styrene (ABS) fuel grains.
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Farjam, Nazanin. "Effects of Size and Geometry on the Thermomechanical Properties of Additively-Manufactured NiTi Shape Memory Alloys." University of Toledo / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=toledo153333222254631.
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Fukuda, Motohisa. "Additivity conjectures in quantum information theory." Thesis, University of Cambridge, 2007. https://www.repository.cam.ac.uk/handle/1810/252051.
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Cencelj, Matija. "Localised equivariant cohomology and Milnor's additivity." Thesis, University of Warwick, 1992. http://wrap.warwick.ac.uk/110582/.
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Borel equivariant cohomology, H τ (X:R), for spaces with circle action is a module over R[u], where u has degree 2. Localised equivariant cohomology u -1 H τ (X:R), provides certain information about H τ (X:R) but as a cohomology theory it has a deficiency in that it does not satisfy Milnor's additivity axiom. In this thesis an equivariant cohomology theory, h τ, is constructed which agrees with u-1 H τ on nice finite-dimensional spaces with circle action and satisfies Milnor's additivity axiom. This has already been done by J.D.S. Jones and S.B. Petrack for the smooth case, where a different method was used which cannot be extended to the general case. We show that h τ satisfies a fixed point theorem similar to the one for u-1 H τ on finite dimensional spaces. Finally, cellular versions of H τ (X:Z), and u -1 H τ (X:Z), are constructed.
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Magee, Kenneth Howard. "The application of the additivity principle to recrystallization." Thesis, University of British Columbia, 1986. http://hdl.handle.net/2429/26311.
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This research is part of an ongoing program at the University of British Columbia to mathematically model industrial annealing processes. To enable one to predict the final mechanical properties of a cold rolled steel sheet after being subjected to an industrial annealing cycle, the progress of recrystallization must be predicted with temperature increase during annealing. This is accomplished by applying the additivity principle to isothermal recrystallization kinetic data.
To determine whether additivity is applicable to recrystallization, isothermal recrystallization kinetic data for a low carbon, rimmed, cold rolled steel sheet, was determined over a temperature range of 440°C-560°C, using molten salt annealing and diamond pyramid microhardness evaluation methods. The data was characterized using the Avrami equation. Continuous heating recrystallization trials were carried out using resistance heated strip specimens. The progress of recrystallization was monitored using an x-ray procedure based on examining the increased Ka doublet peak resolution of the {211} plane, experienced during the formation of recrystallized material. Diamond pyramid microhardness evaluation was also applied to the continuously heated specimens.
Applying the Additivity principle to the isothermal kinetic data resulted in computer predictions which displayed reasonably good agreement with the kinetics obtained experimentally. The difference between the predicted and the experimental recrystallization behaviour was related to recovery effects. The degree of recovery, which is thermal history dependent, determines the amount of stored strain energy available for recrystallization. Once the recovery effect was eliminated by applying suitable heat treatments prior to the continuous heating cycle, the computer predictions displayed excellent correlation with the experimentally obtained continuous heating recrystallization kinetics.
The x-ray procedure used to monitor recrystallization was found to be effective. However, modifications to the procedure will be necessary to enable it's use for the insitu monitoring of specimens subjected to the high heating rates typical of continuous annealing conditions.Applied Science, Faculty of
Materials Engineering, Department of
Graduate
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Thiele, Sonja. "The additivity of the two-dimensional Miller ideal." [S.l.] : [s.n.], 2005. http://e-diss.uni-kiel.de/diss_1591/d1591.pdf.
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Danilevich, Anatoly [Verfasser], and Klaus [Akademischer Betreuer] Mecke. "Gaussian Model and Additivity / Anatoly Danilevich. Gutachter: Klaus Mecke." Erlangen : Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 2014. http://d-nb.info/1075743389/34.
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Kamat, Rajeev Gurunath. "The principle of additivity and the proeutectoid ferrite transformation." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/30682.
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This study critically examines the additivity of the proeutectoid ferrite transformation. The study has been carried out in two parts with the first part involving experimental verification of the additivity of the proeutectoid ferrite transformation and the second part a theoretical assessment of the additive nature of the ferrite transformation with the aid of mathematical models.
Austenite-to-proeutectoid ferrite transformation kinetics were measured under a number of isothermal, stepped-isothermal and continuous-cooling conditions for three plain-carbon hypo-eutectoid steel grades (AISI 1010,1020 and 1040) using a dilatometer and a Gleeble 1500 thermomechanical simulator. Isothermal transformation kinetics were characterized using the Avrami equation. The stepped-isothermal transformation tests were designed to experimentally assess the additive nature of the austenite to proeutectoid ferrite transformation by measuring transformation kinetics partially at one temperature and after a rapid temperature change to another temperature. Results on the 1010 and 1040 steels showed that the proeutectoid ferrite transformation with polygonal morphology is additive under changing temperature in that the ferrite transformation kinetics at the second temperature are quite similar to the isothermal kinetics at that temperature.
Stepped-isothermal transformation measurements were made on the 1020 steel with the resulting ferrite morphology either remaining Widmanstatten at both temperatures or changing from allotriomorph to predominantly Widmanstatten at the two temperatures. In both cases the results showed additive behavior. However, the stepped-isothermal test in which the proeutectoid ferrite was transformed to an equilibrium amount and equilibrated at the first temperature and then rapidly changed to the second temperature was not additive.
Characterizing the isothermal formation of proeutectoid ferrite in the three steels using the Avrami equation resulted in a reasonably constant value of n and the b parameter increasing with increasing transformation temperature. Early site saturation was evident in a number of test specimens.
In the second part of the study, two mathematical models with planar and spherical interface geometries were developed to theoretically assess the additivity of the proeutectoid ferrite transformation. A finite-difference numerical technique was employed to describe the austenite to ferrite diffusion controlled moving-interface problem for a system having finite boundaries. A test of additivity of the proeutectoid ferrite transformation was made by predicting the ferrite growth kinetics and the associated carbon gradients under stepped-isothermal conditions. The predictions were consistent with the observed experimental additivity of the proeutectoid ferrite transformation in the 1010 steel. The spherical model predicted isothermal ferrite growth kinetics compared more favorably with the experimentally measured kinetics of the 1010 steel than the planar model.
An unusual phase was detected in the 1020 steel. A number of tests were performed to measure the isothermal transformation kinetics of the new phase. Scanning electron microscopy (SEM) and scanning-transmission electron microscopy (STEM) were used to further investigate the structural details in this new phase. The results indicated that the new phase is a type of bainite but having some of the characteristics attributable to massive transformation products.Applied Science, Faculty of
Materials Engineering, Department of
Graduate
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Muller, Kimberly O. "Exhaustivity, continuity, and strong additivity in topological Riesz spaces." Thesis, University of North Texas, 2004. https://digital.library.unt.edu/ark:/67531/metadc4455/.
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In this paper, exhaustivity, continuity, and strong additivity are studied in the setting of topological Riesz spaces. Of particular interest is the link between strong additivity and exhaustive elements of Dedekind s-complete Banach lattices. There is a strong connection between the Diestel-Faires Theorem and the Meyer-Nieberg Lemma in this setting. Also, embedding properties of Banach lattices are linked to the notion of strong additivity. The Meyer-Nieberg Lemma is extended to the setting of topological Riesz spaces and uniform absolute continuity and uniformly exhaustive elements are studied in this setting. Counterexamples are provided to show that the Vitali-Hahn-Saks Theorem and the Brooks-Jewett Theorem cannot be extended to submeasures or to the setting of Banach lattices.
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Huff, Cheryl Rae. "Countable Additivity, Exhaustivity, and the Structure of Certain Banach Lattices." Thesis, University of North Texas, 1999. https://digital.library.unt.edu/ark:/67531/metadc278330/.
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The notion of uniform countable additivity or uniform absolute continuity is present implicitly in the Lebesgue Dominated Convergence Theorem and explicitly in the Vitali-Hahn-Saks and Nikodym Theorems, respectively. V. M. Dubrovsky studied the connection between uniform countable additivity and uniform absolute continuity in a series of papers, and Bartle, Dunford, and Schwartz established a close relationship between uniform countable additivity in ca(Σ) and operator theory for the classical continuous function spaces C(K). Numerous authors have worked extensively on extending and generalizing the theorems of the preceding authors. Specifically, we mention Bilyeu and Lewis as well as Brooks and Drewnowski, whose efforts molded the direction and focus of this paper. This paper is a study of the techniques used by Bell, Bilyeu, and Lewis in their paper on uniform exhaustivity and Banach lattices to present a Banach lattice version of two important and powerful results in measure theory by Brooks and Drewnowski. In showing that the notions of exhaustivity and continuity take on familiar forms in certain Banach lattices of measures they show that these important measure theory results follow as corollaries of the generalized Banach lattice versions. This work uses their template to generalize results established by Bator, Bilyeu, and Lewis.
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Lowe, Brian D. "Modelling the additivity of perceived exertion in symmetric, mid-sagittal lifting." Thesis, This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-06112009-063305/.
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Subasic, Mustafa. "The effect of preload on the fatigue strength of additively manufactured 316L stainless steel." Thesis, KTH, Hållfasthetslära, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-285818.
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In this thesis an investigation of the effect of preload on the fatigue behaviour of additively manufactured (AM) 316L stainless steel parts with less than 5 % porosity, for both horizontal and vertical build direction, is presented. The specimens used were manufactured by selective laser melting (SLM) and cut by EDM. Preloads at two different magnitudes were used, below and above the yield strength of the material, and fatigue tests were performed on the specimens with and without the preloads. In addition, microstructural analysis was carried out in order to illustrate/quantify the defects and to realize the corresponding effect of the preload by use of white light interferometry (WLI), SEM and FEM modeling. It was found that the fatigue life and the fatigue limit clearly increase with increasing the preloads in both build directions, although the preload significance might be varied for different directions. This was attributed to the imposed compressive residual stresses and blunting of sharp defects after preloading.I detta examensarbete presenteras en undersökning på effekten av förbelastning på utmattningsbeteendet hos additivt tillverkade (AM) komponenter av 316L rostfritt stål med mindre än 5 % porositet, för både horisontell och vertikal byggriktning. Provstavarana tillverkades genom selektiv lasersmältning (SLM) och skars ut med trådgnist (EDM). Förspänningar i två olika storlekar användes, under och över materialets sträckgräns, och utmattningstester utfördes på provstavarna med och utan förspänningarna. Dessutom genomfördes mikrostrukturella analyser för att illustrera / kvantifiera defekterna och effekten av förspänningen med användning av vitt ljusinterferometri (WLI), SEM och FEM-modellering. Det visade sig att utmattningslivslängden och utmattningsgränsen tydligt ökar med ökad förspänning i båda byggriktningarna, även om förspänningens betydelse kan variera för olika riktningar. Denna positiva effekt på utmattningen kommer från de kompressiva restspänningarna och avstumpningen av skarpa defekter som uppstår efter förbelastningen.
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Dawson, Kathryn S. "Statistical Methods for Detecting and Characterizing Departures from Additivity in Multi-Dimensional Drug/Chemical Mixtures." VCU Scholars Compass, 1995. http://scholarscompass.vcu.edu/etd/4507.
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In studies of the effects of multiple drug or chemical combinations, one goal may be to detect and characterize the interactions between the agents. The techniques currently applied to this problem have limitations when the experiments involve more than 2 agents. Certain response-surface techniques require an unrealistic number of observations for studies involving a large number of agents. Current graphical methods are impossible to use in studies of 3 or more agents. In this research two statistical techniques are described that can be applied to studies with an unlimited number of agents. In the first approach, dose combinations are collected along rays or at fixed ratios. Using properties of this experimental design, an additive model is derived. Comparing the fitted dose-response curve along each ray to the curve predicted under additivity, synergistic and antagonistic interactions between the agents can be detected. Statistical testing procedures are given to determine if these are significant interactions, not due to random fluctuations in the data. Graphical techniques that enhance the interpretation of the results are described. The second approach developed in this research is a point-wise test which determines if the agents interact in an nonadditive manner. This test can be applied to each dose combination of interest After applying a multiple comparison adjustment to the resulting p-values, departures from additivity can then be characterized. These approaches are likely to be more economical than current techniques, implying that a larger number of agents can be studied in combination for the same experimental effort.
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Whip, Bo Ryan. "Effect of Process Parameters on the Surface Roughness and Mechanical Performance of Additively Manufactured Alloy 718." Wright State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=wright1526993831680976.
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Lee, Matthew Colin John. "Correlations between MO Eigenvectors and the Thermochemistry of Simple Organic Molecules, Related to Empirical Bond Additivity Schemes." The University of Waikato, 2008. http://hdl.handle.net/10289/2623.
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A bondingness term is further developed to aid in heat of formation (ΔfHº) calculations for C, N, O and S containing molecules. Bondingness originated from qualitative investigations into the antibonding effect in the occupied MOs of ethane. Previous work used a single parameter for bondingness to calculate ΔfHº in an alkane homologous series using an additivity scheme. This work modifies the bondingness algorithm and uses the term to parameterise a test group of 345 molecules consisting of 17 subgroups that include alkanes, alkenes, alkynes, alcohols, ethers, aldehydes, ketones, carboxylic acids, esters, amines, amides, diazenes, nitriles, nitroalkanes, nitrates, thiols and benzenoids. Comparing experimental with calculated ΔfHº values, a standard deviation for the residuals of 6.3 kJ mol 1 can be achieved using bondingness with a simple steric repulsion term (SSR) in a bond additivity scheme, and a standard deviation of 5.2 kJ mol 1 can be achieved using a Lennard-Jones potential. The method is compared with the group method of Pedley, which for a slightly smaller set of 338 molecules, a subset of the test set of 345 molecules, gives a standard deviation of 7.0 kJ mol 1. Bondingness, along with SSR or a Lennard-Jones potential, is parameterised in the lowest level of ab initio (HF-SCF) or semiempirical quantum chemical calculations. It therefore may be useful in determining the ΔfHº values for the largest molecules that are amenable to quantum chemical calculation. As part of our analysis we calculated the difference between the lowest energy conformer and the average energy of a mixture populated with higher energy conformers. This is the difference between the experimental ΔfHº value and the ΔfHº calculated for a single conformer. Example calculations which we have followed are given by Dale and Eliel et al.. Dale calculates the energy difference for molecules as large as hexane using relative energies based on the number of 1,4 gauche interactions. We have updated these values with constant increments ascertained by Klauda et al. as well as ab initio MP2 cc-pVDZ relative energies and have included calculations for heptane and octane.
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Calabrò, Gaetano. "Accelerating molecular simulations : implication for rational drug design." Thesis, University of Edinburgh, 2015. http://hdl.handle.net/1842/16439.
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The development and approval of new drugs is an expensive process. The total cost for the approval of a new compound is on average 1.0 - 1.2 billion dollars and the entire process lasts about 12 - 15 years. The main difficulties are related to poor pharmacokinetics, lack of efficacy and unwanted side effects. These problems have naturally led to the question if new and alternative methodologies can be developed to find reliable and low cost alternatives to existing practices. Nowadays, computer-assisted tools are used to support the decision process along the early stages of the drug discovery path leading from the identification of a suitable biomolecular target to the design/optimization of drug-like molecules. This process includes assessments about target druggability, screening of molecular libraries and the optimization of lead compounds where new drug-like molecules able to bind with sufficiently affinity and specificity to a disease-involved protein are designed. Existing computational methods used by the pharmaceutical industry are usually focused on the screening of library compounds such as docking, chemoinformatics and other ligand-based methods to predict and improve binding affinities, but their reliable application requires improvements in accuracy. New quantitative methods based on molecular simulations of drug binding to a protein could greatly improve prospects for the reliable in-silico design of new potent drug candidates. A common parameter used by medicinal chemists to quantify the affinity between candidate ligands and a target protein is represented by the free energy of binding. However, despite the increased amount of structural information, predicting binding free energy is still a challenge and this technique has found limited use beyond academia. A major reason for limited adoption in the industry is that reliable computer models of drug binding to a protein must reproduce the change in molecular conformations of the drug and protein upon complex formation and this includes the correct modelling of weak non-covalent interactions such as hydrogen bonds, burials of hydrophobic surface areas, Van der Waals interactions, fixations of molecular degrees of freedom solvation/desolvation of polar groups and different entropy contributions related to the solvent and protein interactions. For several classes of proteins these phenomena are not easy to model and often require extremely computationally intensive simulations. The main goal of the thesis was to explore efficient ways of computing binding affinities by using molecular simulations. With this aim, novel software to compute relative binding free energies has been developed. The implementation is based on alchemical transformations and it extended a preexisted piece of software Sire, a molecular modeling framework, by using the OpenMM APIs to run fast molecular dynamics simulations on the latest GPGPU technology. This new piece of software has equipped the scientific community with a flexible and fast tool, not only to predict relative binding affinities, but also a starting point to develop new sampling methods for instance hybrid molecular dynamics and Monte Carlo. The implementation has been validated on the prediction of relative hydration free energy of small molecules, showing good agreement with experimental data. In addition, non-additive effects to binding affinities in series of congeneric Thrombin inhibitors were investigated. Although excellent agreement between predicted and experimental relative binding affinities was achieved, it was not possible to accurately predict the non-additivity levels in most of the examined inhibitors, thus suggesting that improved force fields are required to further advance the state-of-the art of the field.
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Anjolaiya, Olanrewaju. "Sorption behaviour of metal contaminants in clay minerals, soils and matrices : understanding the influence of organic matter, pH, ionic strength and mineralogy." Thesis, Loughborough University, 2015. https://dspace.lboro.ac.uk/2134/17523.
Full textAbstract:
Many chemical and physical factors govern the mobility of metal contaminants in soils and clay systems; some of these chemical factors include mineralogical composition, cation exchange capacity, organic matter content, pH and the ionic strength of soil water. This makes understanding and therefore predicting the fate of metal contaminants in soils a complex undertaking. There were two broad objectives in this study. The first was to investigate binary and ternary sorption systems, with the aim to understand the effects that factors such as pH, ionic strength, organic matter and metal concentrations, have on sorption of simple clay minerals (bentonite and kaolinite) with metals (cadmium, caesium, nickel and strontium). The second was to investigate the retention of heavy metals and radionuclides by well characterised organic-rich and organic-poor clay soils, breaking them down to their individual components to help understand the effects of each component separately, the study also tested to see if the additivity principle holds for these heavy metals and radionuclides, the additivity principle presumes that the overall sorption behaviour of a complex mixture is a summation of the weighted individual sorption behaviours of its constituents. The study also determined the relationship between the natural organic matter (NOM) content and cation exchange capacity (CEC) of the soils and how these affect the mobility of the metals, while also considering the relative importance of the speciation of the metals. Two British clay soils (Mercia Mudstone and London Clay) and two Nigerian soils (an organic-rich Ikeja Loam and the other organic-poor Magodo Laterite) were characterised by X-ray diffraction (XRD) analysis. Batch techniques were employed for the sorption studies, and radiometric techniques, ICP-OES and ICP-MS were used to quantify metal distribution between phases. The sorption of dissolved organic matter to clay minerals is very dependent on pH; this dependence is greater with increasing concentration of organic matter. The formation of metal-humate complexes is dependent on the nature of the metal and pH. Caesium exhibits no discernible sorption to humic acid, cadmium sorption is enhanced by increasing alkalinity but this enhancement is slightly reduced in higher concentrations of humic acid, nickel sorption is mostly unaffected by pH except in higher concentrations of humic acid and enhanced only under very low concentrations of humic acid, while strontium sorption to humic acid is reduced with increasing alkalinity. The nature and preference of humic acid sorption for these metals are vital to understanding the role played by humic acid in the ternary sorption studies of metals, humic acid and clay minerals. Strongly acidic conditions dominate other factors affecting sorption such as ionic strength in sorption of metals to clay minerals. Caesium sorption to bentonite at pH 4 is poor and almost unaffected by ionic strength of the electrolyte solution; saturation of sorption sites is reached with low amounts of adsorbed caesium. Strontium also binds poorly to bentonite at pH 4, more so than caesium, but an ionic strength effect on sorption still exists and is discernible even under these conditions. Increasing alkalinity has the expected effect of increasing sorption capacity of bentonite for both metals. Bentonite has poor sorption properties, having low affinity for caesium and strontium, but has greater affinity for caesium than strontium. The presence of humic acid can enhance or suppresses sorption, this varies from metal to metal and from solid to solid, the degree of enhancement or suppression also depends on humic acid concentration. Kaolinite has better sorption properties than bentonie. Cadmium has greater sorption affinity for kaolinite in the absence of humic acid, but nickel sorption is more enhanced in the presence of humic acid. Although the presence of humic acid enhances cadmium and nickel sorption to kaolinite, low humic acid concentration provides the best conditions for maximum sorption of both metals. High concentrations of humic acid lead to colloid formation which block access of metals with larger hydration radii to sorption sites while also encouraging the formation of humic acid-metal complexes. As with bentonite, caesium and strontium are both poorly sorbed by kaolinite. Unlike with cadmium and nickel however, the enhancement of strontium sorption is supported by higher concentrations of humic acid, these confirm a greater preference for the formation of S-HA-Sr ternary and lower preference for the formation HA-Sr binary complexes. The presence of humic acid inhibits caesium binding, and retention but this reduces with increasing alkalinity, while the reverse is the case with strontium whose retention is very poor and improved in the presence of humic acid and increasing alkalinity. Both caesium and strontium are poorly sorbed and retained by kaolinite but their retention improves with increasing humic acid concentration and pH. Cadmium and nickel also exhibit poor retention to kaolinite but their retentions are more improved under alkaline conditions and higher humic acid concentrations, nickel more so than cadmium. Similar sorption affinities were exhibited by the British (London Clay and Mercia Mudstone) and Nigerian soils (Magodo Laterite and Ikeja Loam) for the metals studied, showing the significance of soil constituent contribution to sorption behaviour. Both British clay matrices have affinity for the metals in the order Cs >> Cd ≈ Ni >> Sr, London Clay has the greater sorption capacity for all the metals, the clay mineral content of Mercia Mudstone is almost entirely made up of Illite while London Clay contains a mixture of smectite, illite and kaolinite with smectite being the most prevalent clay mineral phase. These confirm that smectite-rich clay systems will exhibit better sorption and retention capacities for metal contaminants. Both Nigerian soils showed the same order of affinity for all the metals Cd >> Ni >> Cs >> Sr, cadmium s preferential sorption to kaolinite was observed in its greater sorption and retention by the Nigerian soils which are kaolinite-rich. This preferential sorption of cadmium by kaolinite is confirmed by the Standard Addition experiment where its contribution to cadmium sorption is clearly evident, a trend not replicated with nickel as the sorbing metal. The presence of organic matter in soils or clay systems improves their metal sorption capacity significantly, especially true for insoluble organic matter, however its significance is reduced as pH increases. The contribution of organic matter also depends on the sorption affinity of the metal for organic matter; metals such like strontium are more affected by organic matter presence. The overall sorption behaviour of complex systems such as soils is difficult to attribute to their individual constituents. The laterite soils can be considered a relatively simple soil system containing only four constituents in significant quantities, yet it is difficult to replicate its sorption behaviour using a replicate proportioned mixture of its constituent phases. The additively calculated sorption profiles for the synthetic laterite were different from those obtained experimentally, the reason for this is that the existence of significant particle size differences between the natural and synthetic soils give rise to differences in the availability of sorption sites which is evident from the different CEC values measured for both systems.
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Sanvido, Cibelle de Souza. "Estudo teorico do mecanismo de eliminação interna de xantatos usando o metodo aditivo de energia atraves de ONIOM com pseudopotencial." [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/248944.
Full textAbstract:
Orientador: Nelson Henrique MorgonDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica
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Mestrado
Físico-Química
Mestre em Química
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Russell, Matthew B. "Modeling the biomass partitioning of loblolly pine grown in a miniature-scale plantation." Thesis, Virginia Tech, 2008. http://hdl.handle.net/10919/31176.
Full textAbstract:
Stand conditions influence the partitioning of biomass to stem, foliage, branch, and root components. Using data from 4 to 6-year old loblolly pine (Pinus taeda L.) trees grown in a miniature-scale spacing trial, this study determined the effect of initial planting density on the biomass partitioning of loblolly pine. An analysis of covariance concluded that density did not have a significant effect on the relative amount of biomass in aboveground components.Some measures of partitioning tradeoffs (such as root: shoot ratio) showed a significant positive slope when regressed against trees per hectare. Systems of linear equations were developed based on tree measurements and age, and additivity was specified. By taking into account contemporaneous correlations among tree components, seemingly unrelated regression (SUR) methodologies led to efficient parameter estimates. When compared to studies with mature trees at operational scales, results from the miniature-scale trees showed similar trends. Stem and woody roots were 70 and 14% of total mass, respectively. Since these miniature-scale trees were physiologically young at time of harvest, allocation of mass to foliage continued to be a priority, occupying 10% of total mass.Master of Science
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PROSPERI, EMILIANO. "Effect of the rejuvenators on the mechanical and performance characteristics of Hot Recycled Mix Asphalt." Doctoral thesis, Università Politecnica delle Marche, 2022. http://hdl.handle.net/11566/295281.
Full textAbstract:
Una delle principali sfide da fronteggiare ai giorni nostri è sicuramente quella di garantire un’economia quanto più possibile circolare. Per questo motivo, in ambito stradale, molteplici benefici economico-ambientali incoraggiano l’uso di fresato (RAP), proveniente dalla demolizione di vecchie pavimentazioni stradali, da introdurre nella produzione di nuovo conglomerato bituminoso a caldo. Tale materiale permette, insieme ad una netta riduzione dei costi di produzione e dei problemi di smaltimento, anche un notevole risparmio delle risorse naturali, grazie allo sfruttamento di entrambi i materiali con cui il RAP è composto (aggregati e bitume). A fronte dei tali vantaggi nell’utilizzare il fresato nella tecnica a caldo, ci sono anche alcune problematiche da fronteggiare, come la sua disomogeneità (sia dal punto di vista della granulometria che del contenuto di bitume), la difficoltà nel garantire e definire un corretto riscaldamento del RAP, sia dal punto di vista logistico (con la necessità di adeguare gli impianti esistenti) che tecnico (occorre limitare l’invecchiamento del bitume vergine e di quello presente nel RAP) che ambientale (con problematiche di emissione di fumi). Inoltre, il bitume contenuto nel fresato risulta essere invecchiato e quindi rigido-fragile, con la conseguente necessità di dover impiegare additivi rigeneranti. Tale invecchiamento del bitume provoca ovviamente una riduzione sia della lavorabilità che delle prestazioni del conglomerato bituminoso di recupero. Tutto ciò fa sì che in Italia e nel mondo ci siano tutt’ora delle limitazioni sulla percentuale di RAP utilizzabile nel riciclaggio a caldo. Negli ultimi anni la ricerca si sta muovendo cercando di studiare queste problematiche, trovando delle soluzioni per arrivare a poter riutilizzare il 100% di fresato anche con la tecnica a caldo garantendo quindi un riciclo continuo e circolare.
In questo contesto, l’attività di dottorato ha come scopo principale quello di studiare ed analizzare le proprietà reologiche, meccaniche e prestazionali del conglomerato bituminoso riciclato a caldo al variare della tipologia di additivo rigenerante, del processo produttivo del bitume vergine, della temperatura di produzione della miscela ed infine del tempo di permanenza in forno della miscela sfusa dopo la fase di miscelazione.
Sulla base delle evidenze sperimentali ottenute si può affermare che l’impiego di un elevato contenuto di RAP (pari al 50%) è possibile, senza l’insorgenza di effetti dannosi sulla miscela finale se la tecnica di produzione e compattazione, la provenienza e le proprietà del RAP, del bitume vergine e dell’additivo rigenerante sono selezionate e scelte opportunamente. In particolare, usare una ragionevolmente bassa temperatura di miscelazione (sufficiente da rendere il bitume lavorabile) ed un buon bitume primario comporta la produzione di un conglomerato bituminoso riciclato a caldo con ottime proprietà reologiche e meccaniche tali da essere duraturo nel tempo senza soffrire di problemi fessurativi. Inoltre, l’analisi degli effetti del successivo invecchiamento del bitume rigenerato ha portato a concludere che tale re-invecchiamento produce un bitume aventi caratteristiche reologiche pressoché comparabili a quelle di un bitume vergine invecchiato per la prima volta, confermando così la possibilità di riutilizzare il bitume rigenerato per la produzione di nuove pavimentazioni stradali.Nowadays, one of the main challenges to face up is the development of a circular economy. For this purpose, in the road sector, many economic and environmental benefits encourage the use of the Reclaimed Asphalt Pavement (RAP) to produce new Hot Mix Asphalt (HMA). Such material, together with an important cost and landfill issues reduction, leads to a considerable saving of natural resources, thanks to the re-use of both materials contained into it (aggregates and bitumen). Despite several benefits in using RAP with the Hot-Recycling technique, many issues also arise. Some of the main problems are its isogeneity (both from aggregate gradation and bitumen content) and the difficulties in defining and ensuring the correct heating of the recycled material from a logistical (needing to adapt existing plants) technical (necessity to limit the aging of both virgin and recycled bitumen) and environmental point of view (CO2 emission). Moreover, the aged and brittle bitumen contained into RAP leads to the reduction of the workability and the performance of the Hot Recycled Mix Asphalt (HRMA) with the consequent and inevitable need to add additives called rejuvenators. All these issues explain why in Italy and all around the world, there are still many limitations on the percentage of RAP that can be re-used in hot recycling techniques. Recently, research has been moving on trying to develop solutions to allow the 100% reuse of RAP even with the hot technique, thus guaranteeing the continuous and circular recycling. In this context, the main purpose of this PhD research activity is to study and analyse the rheological, mechanical and performance characteristics of HRMA changing the type of rejuvenator, the distillation process of the virgin bitumen, the pre-heating and mixing temperature and the loose mixture time spent in the oven after the mixing process. Based on the experimental findings, it can be stated that the use of a high RAP content (equal to 50%), without compromising the properties of the HRMA is possible if the production and compaction process, the origin and the properties of the RAP material, the virgin bitumen and the rejuvenator are properly selected. In particular, it was found out that using a reasonably low mixing temperature (enough to make the bitumen workable) and a good straight-run virgin bitumen plays a fundamental role in the production of an HRMA that achieves optimal rheological and mechanical characteristics and is therefore durable over time without suffering from cracking issues. Moreover, the analysis of the effects of a second aging of the rejuvenated bitumen led to the conclusion that the re-aging induces a bitumen having rheological characteristics almost comparable to those of a virgin bitumen first time aged. Thus, the possibility to reuse the rejuvenated bitumen for the production of new asphalt pavements is achieved.
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AL, Nuwairan Muneerah. "SU(2)-Irreducibly Covariant Quantum Channels and Some Applications." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/32123.
Full textAbstract:
In this thesis, we introduce EPOSIC channels, a class of SU(2) -covariant quantum channels. For each of them, we give a Stinespring representation, a Kraus representation, its Choi matrix, a complementary channel, and its dual map. We show that these channels are the extreme points of all SU(2) -irreducibly covariant channels. As an application of these channels to the theory of quantum information, we study the minimal output entropy of EPOSIC channels, and show that a large class of these channels is a potential example of violating the well-known problem, the additivity problem. We determine the cases where their minimal output entropy is not zero, and obtain some partial results on the fulfillment of their entanglement breaking property. We find a bound of the minimal output entropy of the tensor product of two SU(2) -irreducibly covariant channels. We also get an example of a positive map that is not completely positive.
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Mendes, Leandro Raffhael da Silva 1990. "Structure of states saturating the bounded strong sub-additivity and quantum channels = Estrutura de estados que saturam a subaditividade forte limitada e canais quânticos." [s.n.], 2016. http://repositorio.unicamp.br/jspui/handle/REPOSIP/305753.
Full textAbstract:
Orientadores: Marcos César de Oliveira, José Antonio RoversiDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin
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Resumo: Estudamos a estrutura de estados que saturam a desigualdade de subaditividade forte da entropia de von Neumann. Isto foi feito rearranjando a forma das medidas apresentadas na desigualdade, de tal maneira que o teorema de Petz pudesse ser utilizado. Após a aplicação de um mapa de recuperação, vemos que os estados resultantes requerem que o emaranhamento de formação para um estado tripartido e para um estado bipartido sejam iguais, ou em outras palavras, exige a existência de monogamia do emaranhamento de formação. Também foram analisadas as implicações da relação de subaditividade na desigualdade de processamento de dados quântica. Nós vemos que o limitante existente na relação anterior é estendido à desigualdade de processamento de dados, mas com uma forma diferente. Manipulando o limitante nós conseguimos escreve-lo como sendo a diferença entre o fluxo resultante de informação localmente inacessível na primeira fase do processamento de dados e o fluxo resultante no segundo estágio do processo. Isto mostra que a diferença entre a informação coerente em relação a duas partes que estão processando um estado é limitada inferiormente pela diferença desses dois fluxos
Abstract: We studied the structure of states that saturate the bounded strong subbaditivity of von Neumann entropy. This was done by rearranging the form of the measures presented in the inequality, in such a way that the Petz theorem could be used. After the application of a recovery map we see that the resulting states require the entanglement of formation for a tripartite and bipartite case to be equal, or in other words, it requires monogamy of the entanglement of formation. We also analyzed the implications of the bounded relation into the quantum data processing inequality. It is seen that a bound is extended from the strong subbaditivity to the data processing inequality, but with different terms, with further manipulations we show that the bound can be expressed in terms of the net flow of locally inaccessible information in the first stage and the net flow on the second stage. Were the difference between the coherent information relative to two parties in the process of transmitting a state is lower bounded by the difference on the net flows
Mestrado
Física
Mestre em Física
1247649/2013
CAPES
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Oulton, David. "Selected papers on colorimetric theory and colour modeling." Thesis, University of Manchester, 2010. https://www.research.manchester.ac.uk/portal/en/theses/selected-papers-on-colorimetric-theory-and-colour-modeling(e4f13600-5d8e-45a8-afce-846647130dfb).html.
Full textAbstract:
The annotated papers that are submitted as part of this thesis consider the phenomenon of colour at the fundamental, technical, and application levels, and they were written and published by Oulton between 1990 and 2009. The papers disclose significant insights by the author into colorimetric modeling theory and report aspects of the author's work that have led to commercially successful practical applications. The academic significance of these papers is evident in their citation record; their practical value is shown by a number of successful industrial collaboration programmes, and through the award of national prizes for innovation by the Worshipful Company of Dyers, and the Society of Dyers and Colorists. The published research primarily concerns digital devices that either capture or reproduce coloured images. For example, the research problem of how to calibrate the colour on computer CRT screens, which was thought at the time to be intractable, was reported by Oulton in paper 1 to be solved at the two to three significant figure level of colorimetric accuracy. This world leading level of accuracy was subsequently confirmed using a comprehensive data set in paper 7, and has been exploited internationally in commercial computer aided design and colour communication systems by Textile Computer Systems Ltd and Datacolor Inc. Further research problems resolved by Oulton in the presented papers include how to predict the colorimetric sensitivity of dye recipes; how to design, test, and fine-tune the spectral response of digital cameras; and how the individual customers in a shop can be tracked automatically to reveal their buying behavior, using coloured CCTV images.The challenge to the standard CIE colorimetric model posed by the results of Dr W.A. Thornton was analyzed and satisfactorily explained by Oulton in papers 2, 3 and 4. It is also shown that Thornton's results do not in any way compromise either the practice of colorimetry based on the CIE Standard Observer, or the validity of its quantifying data sets. It is also additionally shown under the annotation of paper 4 presented here, that the success of the CIE colorimetric model has a clearly demonstrable theoretical basis.In all but one of the presented papers the convention is maintained that the standard CIE XYZ co-ordinate model should be used as the reference basis, when modeling the properties of colour and quantifying its uses. The final paper to be published (and presented here as paper 4) challenges this convention and demonstrates that a context free and formally defined alternative reference basis may be used in colorimetric modeling with significant advantage. It is also shown in paper 4 that under the specified axioms, any cross dependency that is potentially non linear can in principle be resolved into its component scalar and additive relationships, and that the causes of scalar non linearity may be characterized independently from the causes of linearly additive cross dependency. The result is a widely applicable analytical and experimental design method for resolving complex cross dependent relationships in general and in particular, for resolving those between the spectral visual stimuli and the psychophysical response to them.
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Hanni, M. (Matti). "Static and dynamic NMR properties of gas-phase xenon." Doctoral thesis, University of Oulu, 2011. http://urn.fi/urn:isbn:9789514294570.
Full textAbstract:
Abstract
This thesis presents computational studies of both the static and dynamic parameters
of the nuclear magnetic resonance (NMR) spectroscopy of gaseous xenon.
First, state-of-the-art static magnetic resonance parameters are computed in small
xenon clusters by using methods of quantum chemistry, and second, time-dependent
relaxation phenomena are investigated via molecular dynamics simulations
at different experimental conditions. Based on the underlying quantum and
classical mechanics concepts, computational methods represent a procedure complementary
to experiments for investigating the properties of atoms, molecules,
clusters and solids.
Static NMR spectral parameters, chemical shift, shielding anisotropy and asymmetry
parameter, nuclear quadrupole coupling, and spin-rotation coupling, are
calculated using different electronic structure methods ranging from the uncorrelated
Hartree-Fock method to correlated second-order Møller-Plesset many-body
perturbation, complete/restricted active space multiconfiguration self-consistent
field, and to coupled-cluster approaches. The bond length dependence of these
properties is investigated in the xenon dimer (Xe2). A well-characterized property
in experimental NMR, the second virial coefficient of nuclear shielding, is
theoretically calculated by a variety of methods and convincingly verified against
experimental findings. Here, it is mandatory to include effects from special relativity
as well as electron correlation. As a side result, a purely theoretical potential
energy curve for Xe2, comparable to best experimental ones, is calculated.
A pairwise additive scheme is established to approximate the NMR properties in
differently coordinated sites of xenon clusters Xen (n = 2 - 12). Especially the
pairwise additive chemical shift values are found to be in close agreement with
quantum-chemical results and only a small scaling factor close to unity is needed
for the correct behavior. Finally, a dynamical magnetic resonance property, the
experimental nuclear spin-lattice relaxation rate R1 of monoatomic Xe gas due to
the chemical shift anisotropy (CSA) mechanism is validated from first principles.
This approach is based on molecular dynamics simulations over a large range of
temperatures and densities, combined with the pairwise additive approximation
for the shielding tensor. Therein, the shielding time correlation function is seen
to reflect the characteristic time scales related to both interatomic collisions and
cluster formation. For the first time, the physics of gaseous xenon is detailed in
full in the context of CSA relaxation.
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Estruch-Sánchez, Yolanda. "TAKK, för spanskan! Tecken som Alternativ och Kompletterande Kommunikation i spanskundervisningen." Thesis, Malmö universitet, Fakulteten för lärande och samhälle (LS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-28651.
Full textAbstract:
Syftet med detta examensarbete var att undersöka potentialen av TAKK (Tecken Som Alternativ och Kompletterande Kommunikation) i undervisningen av främmande språk i den svenska skolan. Genom en kvasiexperimentell utvärdering tillämpades TAKK under en lektion i spanska där 18 elever skulle lära sig 24 nya ord om mat. Eleverna gick i åk 6 och studerade nybörjarspanska. Orden lärdes ut på ett traditionellt sätt genom att säga och skriva dem men orden 1-12 ackompanjerades dessutom av ett TAKK tecken som eleverna uppmanades att härma. Eleverna förhördes skriftligt vid tre tillfällen på en period av två veckor; glosförhör 1 bestod av 24 ord utan bilder på tecknen, glosförhör 2 bestod av 24 ord och bilder på tecknen för orden 1-12. Glosförhör 3 bestod av endast 12 bilder på tecknen för ord 1-12. Orden skulle översättas till svenska förutom vid tredje tillfället där det skulle skrivas på spanska. I ljuset av Paivios (1971) Dual Coding Theory och The Additivity Hypothesis visade resultatet på glosförhören en positiv inverkan av gesterna/tecknen på inlärningen av orden. Alla elever fick ett högre antal rätt översatta ord vid glosförhör 2. Man kan försiktigt dra slutsatsen att tecknen från TAKK bidrog till en förbättrad memorering av orden då de lagrades i vårt multimodala minne där de lämnade två interrelaterade minnesspår.
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Ciccone, Vanessa. "The Effectiveness of Special Effects: Practical Effects vs. Digital Effects." Thesis, University of Oregon, 2016. http://hdl.handle.net/1794/20500.
Full textAbstract:
For centuries films have given filmmakers the ability to affect their audiences visually and emotionally. Special effects and digital effects make a fictional scene appear more realistic. In the film An American Werewolf in London, make-up artist Rick Baker revolutionized the use of practical effects when transforming David Naughton’s character into a werewolf. In 1997 when An American Werewolf in Paris was released, director Anthony Waller utilized digital effects, instead of practical effects, when transforming various characters into werewolves. These transformation scenes were not met with as much praise as its predecessor. If we were to have a better understanding of how individuals perceive practical effects and digital effects it would allow us to determine which one better conveys an emotional reaction. This thesis will demonstrate which type of special effect, practical effects or digital effects, is more effective at relaying an emotional response in a viewer.
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Kelly, Vincent. "β–alanine: performance effects, usage and side effects." Thesis, University of Queensland, 2017. https://eprints.qut.edu.au/180848/1/43068631.pdf.
Full textAbstract:
β-alanine is a relatively new ergogenic aid and a number of questions relating to its effectiveness in enhancing high intensity exercise performance remain to be addressed. The five studies described in this thesis examined the influence of β-alanine supplementation and high intensity training on exercise capacity and considered factors that potentiallyinfluence dosage compliance and side effects – factors that may impact on the ergogenic value of β-alanine supplementation.Study 1 examined the efficacy of β-alanine supplementation in conjunction with repeated sprint and sprint interval training (and combined with a pre-exercise dose of sodium bicarbonate), on repeated-sprint ability and high intensity cycling capacity (time to fatigue at 110% of maximum power output). β-alaninesupplementation, when combined with sprint and interval training, improved repeated sprint ability but did not influence high intensity cycle capacity. Furthermore, acute sodium bicarbonate ingestion improved high intensity cycle capacity before training but had no influence on either repeated sprint ability or exercise capacity after training. It is likely that intramuscular buffer capacity increased as a result of training and that this may have outweighed the potential ergogenic buffering effects of β-alanine and sodium bicarbonate(i.e., both alone and in combination). Study 2 investigatedβ-alanine supplementation use and level of knowledge amongstprofessional rugby union (n = 87), rugby league (n = 180) and Australian Rules Football (n = 303) players. Over half the professional footballers surveyed used β-alanine, yet mostsupplemented in a manner inconsistent with recommendations. A better understanding of the environment and culture within professional football codes is required before supplement use aligns with evidence-based β-alanine supplementation recommendations. In light of these findings, Study 3 examined compliance levels to β-alanine supplementation in an applied setting. Compliance over a 28 day period was 59% (± 24%) which was significantly lower than the mean compliance rate reported by others (96%) (p < 0.0001). It was concluded that the determinants of β-alanine (non-) compliance in athletes needed to be further investigated.Study 4examined potential relationships between different β-alanine dosages and side effects. Healthy male participants were divided into low (< 75 kg) and high (> 85kg) body mass groups and completed three supplementation treatments: 1. a placebo, 2. β-alanine as a relative dose of 0.02 g·kgBM-1 and 3. β-alanine as an absolute dose of 1.6 g. For 90 min following supplementation in each condition, participants completed a questionnaire that sought responses to side effects. It was found that lighter individuals experienced fewer side effects when they supplemented with β-alanine as a dose relative to body mass; heavier individuals experienced fewer side effects when they consumed an absolute dose of 1.6 g. It was concluded that individualising the supplementation of β-alanine is likely to reduce side effects and in turn improve compliance. Finally, Study 5assessed whether the paraesthesia experienced following acute β-alanine supplementation was related to high intensity exercise performance. There was no relationship between the level of paraesthesia experienced by participants and exercise capacity. However, individual differences in side effects were found after repeated doses of β-alanine and some participants experienced side effects after consuming the slow release β-alanine formula. The findings of Study 5 highlight the need to further understand the underlying mechanismof side effects and impress the need to monitor and report side effects in future studies – particularly in β-alanine supplementation studies where participant blinding is required. Collectively, the studies described in the present thesis extend knowledge relating to β-alanine supplementation; specifically how supplementation practices can be individualised to improve compliance by practitioners and sport scientists in applied settings.
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Leber, Kyle W. "PARK EFFECTS." Bowling Green State University / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1149720032.
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Taylor, Tamsen E. "Strategic effects in naming, effects of the time criterion." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape15/PQDD_0001/MQ32516.pdf.
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Jackson, Eric D. "Cortisol Effects on Emotional Memory: Independent of Stress Effects." Diss., The University of Arizona, 2007. http://hdl.handle.net/10150/196155.
Full textAbstract:
The primary aim of this dissertation is to clarify how stressful experiences impact the formation of emotional memory. The first portion reviews historical evidence that numerous emotional memory phenomena, as well as conceptualizations thereof, span multiple cultural traditions and extend to ancient art and literature. Emotional memory phenomena involving stress-induced amnesia, such as psychogenic amnesia and recovered memories of trauma, is found to be less ubiquitous. The review of historical conceptualizations of emotional memory is followed by a review of modern research and theory, much of which is informed by animal models and cognitive neuroscience. These reviews provide a variety of testable hypotheses that are addressed by the three original experiments reported here. The first involved inducing stress in human subjects before they encoded emotional or neutral material, then assessing long-term memory and its relationship with salivary cortisol concentrations. The second involved administering different doses of cortisol to human subjects immediately before they encoded emotional or neutral material, then assessing long-term memory and its relationship with salivary cortisol concentrations. The third involved inducing stress in human subjects while presenting a combined memory encoding and fear conditioning task. Long-term episodic and fear memory were tested and compared with salivary cortisol concentrations. The experimental results indicated that mildly emotional stimuli formed stronger memories than indifferent stimuli, but that emotionally stressful experiences partially impeded the formation of memories about the experience, even while facilitating emotional learning (fear conditioning) during the experience. The results also indicated that the stress hormone cortisol was likely not responsible for the stress-induced memory alterations, disaffirming some popular theories and animal models. Rather, cortisol appeared to produce independent effects that dose-dependently promoted the storage of particular aspects of memory. The neurobiological underpinnings of these results and how the findings fit with historical and modern conceptualizations of emotional memory is discussed.
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Jaafar, A. Aziz. "Accounting harmonisation in Europe : country effects and sector effects." Thesis, Bangor University, 2004. https://research.bangor.ac.uk/portal/en/theses/accounting-harmonisation-in-europe--country-effects-and-sector-effects(1c582a11-9d1c-4ca1-9ffc-6240975802c6).html.
Full textAbstract:
In measuring harmonisation, prior research has focused almost exclusively on the country of domicile of the firm in quantifying differences in financial reporting practices. However, this approach offers little by way of explanation of the impact of the harmonisation process, particularly as different financial reporting treatments may be attributable to the specific characteristics of the firms that are selected for analysis. The main aim of the present study is to address this issue and to measure de facto accounting harmonisation by taking into account firms' operating circumstances. Specifically, it seeks to assess the combined effects of each firm's country of domicile and sector of operations on its choice of accounting methods, together with the firm's size and international exposure, and any changes in these factors through time. In addition, it assesses the impact of sector diversifications on accounting policy choice. This research sets out the results of a statistical analysis of financial reporting harmonisation, obtained by employing a logistic regression to predict the odds of using alternative accounting methods. The policies studied concern inventory, depreciation and goodwill. The empirical results suggest that country of domicile and sector of operations are each significant determinants of the choice of accounting method across the European Union. However, country differences still appear to be greater than sector differences, even allowing for differences between countries in industrial structure, which is inconsistent with harmonized accounting. In addition, international listing and firm size appear to be significant variables. Indeed, there has been little significant change in policy choices through time amongst European firms. This leads to the conclusion that, rather than a process of convergence, a combination of structural factors at the finn level that demand different accounting treatments and barriers to han-nonisation at the country level that restrict choice are the likely causes of persistent international differences in accounting. Prior research that attempts to measure harnionisation on the basis of convergence towards uniformity without allowing for the use of different accounting methods in different circumstances is entirely misinformed. Indeed, comparability between financial statements requires that the reported results reflect the different circumstances in which firms operate, and the harmonisation metric must take this into account.
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Sandström, Paul A. "The neural effects of palytoxinThe neural effects of palytoxin." Thesis, Queensland University of Technology, 2000. https://eprints.qut.edu.au/36765/1/36765_Digitised%20Thesis.pdf.
Full textAbstract:
Palytoxin, the most potent known marine toxin, has been demonstrated to produce acute neurological disturbances in several animal species and, possibly, even in humans. However, the effects of palytoxin on excitable membranes have not been well characterised or explained.
Palytoxin occurs within the same ecosystem in which other seafood toxins such as ciguatoxin, saxitoxin and brevetoxins are found. Also, several reports suggest that, occasionally, palytoxin may contribute to the ciguatera syndrome. As these other toxins are known to affect the sodium ion channel, either by activation or inactivation, evidence that palytoxin may also affect this structure was sought.
The studies performed on the ventral coccygeal nerve of the rat tail, subsequent to an intraperitoneal injection of palytoxin, demonstrated a significant slowing of mixed nerve and motor conduction velocities and a reduction in the amplitude of the mixed nerve and motor action potentials. However, palytoxin exerted no effect on the latency of the shortest F-wave response. In the palytoxin-treated group, the absolute and relative refractory periods were prolonged. Palytoxin also appeared to induce a significant prolongation of the supernormal period of nerve excitability. The response of the palytoxin-treated ventral coccygeal nerve to repetitive stimulation demonstrated no consistent abnormality.
These studies lend indirect support to the proposition that at least one action of palytoxin is that of an alteration in the excitability of neural tissue by inducing persistent sodium ion channel activation.
Lignocaine, administered via the intraperitoneal route, was demonstrated to reverse many of the electrophysiological disturbances and, particularly, the prolonged supernormal period, in palytoxin-treated rats. These results suggest that prior activation of sodium ion channels by palytoxin may be blocked by lignocaine.
Ethanol, administered via the intraperitoneal route, was observed to reverse many of the electrophysiological disturbances recorded in the palytoxin-treated rats, however, the supernormal period remained prolonged, yet not particularly enhanced or diminished in magnitude.
Ouabain, administered via the intraperitoneal route, also reversed many of the electrophysiological disturbances induced in palytoxin-treated rats. However, in these animals, the palytoxin-induced supernormal period remained prolonged, yet not exaggerated or diminished in magnitude. These results suggest that membrane excitability may occur independently of, or with, the (Na+,K+)A TPase mechanism.
The effect of palytoxin on mammalian nerve tissue appeared to be modified at a lower temperature. Mixed nerve and motor conduction, F-wave responses, absolute and relative refractory period and supernormal period studies were performed on palytoxin-treated animals at 25°C. The only significant abnormalities were a prolongation of the relative refractory period and of the supernormal period. This study suggests that, at least, in mammalian nerve tissue, this toxin is less active at a lower ambient temperature.
In terms of central studies, in palytoxin-treated rats the brainstem auditory evoked response was not significantly altered although there was significant prolongation of the corticospinal evoked response. This finding suggests that palytoxin is capable of crossing the blood-brain barrier and, then, exerting an effect on central nerve membranes.
These results are similar to those induced by ciguatoxin in the ventral coccygeal nerve of the rat. Both toxins produce slowing of the mixed nerve and motor conduction velocities, a reduction in the amplitude of the mixed nerve and motor action potentials and a prolongation of the refractory period and supernormal period. Lignocaine abolishes the supernormal period induced by both toxins. At a temperature of 25°C, both toxins produce reduced electrophysiological effects, in comparison with those produced at 37°C.
Ciguatoxin is known to bind to and to activate or open sodium ion channels. These studies suggest that at least one action of palytoxin may be that of a similar activation of sodium ion channels.
With reference to these studies and to the fact that both toxins occur within the same ecosystem, palytoxin could potentially contribute, on occasions, to the ciguatera syndrome.
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Aktan, Mikael. "Dynamic hair effects." Thesis, University of Gävle, Department of Mathematics, Natural and Computer Sciences, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-187.
Full textAbstract:
Creating three dimensional hair is still one of the hardest elements when creating characters. Problems occur because of the constant changes in the software every few years. A major goal is to create as realistic hair as possible in Autodesk Maya and to supply this detailed information on to other 3D artist. Techniques are researched and reviewed on how different hair systems are created, as well as how dynamic effects react on the moving hair.
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Gibbs, Stephen R. "Information-generated effects." Thesis, Monterey, California. Naval Postgraduate School, 2010. http://hdl.handle.net/10945/4991.
Full textAbstract:
Approved for public release; distribution is unlimitedThis thesis researches three types of information-generated effects that are often observed in police operations: 1) anticipatory effects, 2) diffusion effects, and 3) residual effects. These information generated effects depict the fact that criminal activity often decreases before a new police operation starts, decreases outside the geographical areas where the police operations are occurring, and regularly remains lower for an extended period of time after an operation has concluded. These disruptions in criminal activity are thought to occur because of an increase in the perceptions of risk and uncertainty in response to information about changes in enforcement presence and activities. The purpose of this research is to propose that anticipatory effects, diffusion effects, and residual effects can be planned into counterinsurgency operations to increase their effectiveness. These effects might be achieved through the oscillatory use of information operations that target an insurgent's perceptions of risk and uncertainty about security force operations occurring in circumscribed areas.
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Sanchez, Alejandro Gonzalez. "Cosmological alignment effects." Thesis, University of Sussex, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.385966.
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Quaas, Johannes, Yi Ming, Surabi Menon, Toshihiko Takemura, M. Wang, Joyce E. Penner, Andrew Gettelman, et al. "Aerosol indirect effects." Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-186329.
Full textAbstract:
Aerosol indirect effects continue to constitute one of the most important uncertainties for anthropogenic climate perturbations. Within the international AEROCOM initiative, the representation of aerosol-cloud-radiation interactions in ten different general circulation models (GCMs)
is evaluated using three satellite datasets. The focus is on stratiform liquid water clouds since most GCMs do not include ice nucleation effects, and none of the model explicitly parameterises aerosol effects on convective clouds. We compute statistical relationships between aerosol optical depth (tau a) and various cloud and radiation quantities in a manner that is consistent between the models and the satellite data. cloud droplet number concentration (N d) compares relatively well to the satellite data at least over the ocean. The relationship between (tau a) and liquid water path is simulated much too strongly by the models. This suggests that the implementation of the second aerosol indirect effect mainly in terms of an autoconversion parameterisation has to be revisited in the GCMs. A positive relationship between total cloud fraction (fcld) and tau a as found in the satellite data is simulated by the majority of the models, albeit less strongly than that in the satellite data in most of them. In a discussion of the hypotheses proposed in the literature to explain the satellite-derived strong fcld–tau a relationship, our results indicate that none can be identified as a unique explanation. Relationships similar
to the ones found in satellite data between tau a and cloud top
temperature or outgoing long-wave radiation (OLR) are simulated
by only a few GCMs. The GCMs that simulate a negative OLR - tau a relationship show a strong positive correlation between tau a and fcld. The short-wave total aerosol radiative forcing as simulated by the GCMs is strongly influenced by the simulated anthropogenic fraction of tau a, and parameterisation assumptions such as a lower bound on Nd. Nevertheless, the strengths of the statistical relationships are good
predictors for the aerosol forcings in the models. An estimate of the total short-wave aerosol forcing inferred from the combination of these predictors for the modelled forcings with the satellite-derived statistical relationships yields a global annual mean value of −1.5±0.5Wm−2. In an alternative approach, the radiative flux perturbation due to anthropogenic
aerosols can be broken down into a component over the cloud-free portion of the globe (approximately the aerosol direct effect) and a component over the cloudy portion of the globe (approximately the aerosol indirect effect). An estimate obtained by scaling these simulated clearand cloudy-sky forcings with estimates of anthropogenic tau a
and satellite-retrieved Nd–tau a regression slopes, respectively, yields a global, annual-mean aerosol direct effect estimate of −0.4±0.2Wm−2 and a cloudy-sky (aerosol indirect effect) estimate of −0.7±0.5Wm−2, with a total estimate of −1.2±0.4Wm−2.
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Quaas, Johannes, Yi Ming, Surabi Menon, Toshihiko Takemura, M. Wang, Joyce E. Penner, Andrew Gettelman, et al. "Aerosol indirect effects." Atmospheric chemistry and physics (2009) 9, S. 8697-8717, 2009. https://ul.qucosa.de/id/qucosa%3A13849.
Full textAbstract:
Aerosol indirect effects continue to constitute one of the most important uncertainties for anthropogenic climate perturbations. Within the international AEROCOM initiative, the representation of aerosol-cloud-radiation interactions in ten different general circulation models (GCMs)
is evaluated using three satellite datasets. The focus is on stratiform liquid water clouds since most GCMs do not include ice nucleation effects, and none of the model explicitly parameterises aerosol effects on convective clouds. We compute statistical relationships between aerosol optical depth (tau a) and various cloud and radiation quantities in a manner that is consistent between the models and the satellite data. cloud droplet number concentration (N d) compares relatively well to the satellite data at least over the ocean. The relationship between (tau a) and liquid water path is simulated much too strongly by the models. This suggests that the implementation of the second aerosol indirect effect mainly in terms of an autoconversion parameterisation has to be revisited in the GCMs. A positive relationship between total cloud fraction (fcld) and tau a as found in the satellite data is simulated by the majority of the models, albeit less strongly than that in the satellite data in most of them. In a discussion of the hypotheses proposed in the literature to explain the satellite-derived strong fcld–tau a relationship, our results indicate that none can be identified as a unique explanation. Relationships similar
to the ones found in satellite data between tau a and cloud top
temperature or outgoing long-wave radiation (OLR) are simulated
by only a few GCMs. The GCMs that simulate a negative OLR - tau a relationship show a strong positive correlation between tau a and fcld. The short-wave total aerosol radiative forcing as simulated by the GCMs is strongly influenced by the simulated anthropogenic fraction of tau a, and parameterisation assumptions such as a lower bound on Nd. Nevertheless, the strengths of the statistical relationships are good
predictors for the aerosol forcings in the models. An estimate of the total short-wave aerosol forcing inferred from the combination of these predictors for the modelled forcings with the satellite-derived statistical relationships yields a global annual mean value of −1.5±0.5Wm−2. In an alternative approach, the radiative flux perturbation due to anthropogenic
aerosols can be broken down into a component over the cloud-free portion of the globe (approximately the aerosol direct effect) and a component over the cloudy portion of the globe (approximately the aerosol indirect effect). An estimate obtained by scaling these simulated clearand cloudy-sky forcings with estimates of anthropogenic tau a
and satellite-retrieved Nd–tau a regression slopes, respectively, yields a global, annual-mean aerosol direct effect estimate of −0.4±0.2Wm−2 and a cloudy-sky (aerosol indirect effect) estimate of −0.7±0.5Wm−2, with a total estimate of −1.2±0.4Wm−2.
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Janiszewski, Marcin Józef. "Audio effects unit." Master's thesis, Universidade de Aveiro, 2011. http://hdl.handle.net/10773/6237.
Full textAbstract:
Mestrado em Engenharia Electrónica e TelecomunicaçõesO objectivo principal da presente tese de mestrado centrou-se no desenho e construção de uma unidade de efeitos de áudio (Audio Effects Unit -AEU), cuja função consiste em processar sinais áudio em tempo real. O propósito central foi desenvolver uma unidade de processamento áudio genérica, cuja função de processamento, implementada no domínio digital, pode ser facilmente especificada pelo utilizador via uma aplicação de software implementada num computador. A primeira etapa deste projecto consistiu na implementação completa do hardware que constitui o AEU. É importante acrescentar que esta concepção teve em conta a inclusão desse hardware numa caixa apropriada. Este método de projecto e implementação constituiu uma experiência muito interessante e útil. A próxima etapa consistiu no desenvolvimento de algoritmos matemáticos a ser implementados no microcontrolador do AEU e que geram os efeitos sonoros desejados por processamento dos sinais áudio originais. Estes algoritmos foram inicialmente testados através do Matlab. Para controlar os efeitos sonoros produzidos foi ainda criada uma aplicação de computador que permite a intervenção, de forma muito simples, do utilizador. A referida aplicação assegura a comunicação entre o microcontrolador do AEU e o computador através de uma ligação USB. O dispositivo, na sua versão final, foi testado em laboratório e através do Matlab. Cada bloco do dispositivo, e o dispositivo completo, foi testado individualmente. Com base nessa avaliação foram desenhadas as respectivas características na frequência e analisada a qualidade do dispositivo de áudio. Para além da experiência adquirida em concepção de hardware, este projecto permitiu-me alargar o meu conhecimento em programação de microcontroladores e na optimização de código, um requisito do processamento de sinal em tempo real. Também me deu a oportunidade de utilizar a ferramenta comercial MPLAB para programação de microcontroladores.
The main aim of this master thesis was to design and build an Audio Effects Unit (AEU), whose function is to process, a particular audio signal in real time. The objective was to develop a general purpose audio processing unit where the processing function, implemented in the digital domain, can be easily specified by the user by means of a software application running on a computer. The first stage of this project consisted on the full design and implementation of the hardware that constitutes the AEU. It is worth adding that such design also considered that the layout could be placed in an enclosure. Such way of designing was a great new experience. The next stage was to prepare the mathematical algorithms to be implemented in the AEU microcontroller which create the sound effects by processing the original audio signal. These algorithms were first tested in MatLab. To control the produced sound effects a computer program was created which allows the user intervention in a straightforward way. This program ensures communication between the AEU microcontroller and PC software using an USB connection. The completed device was tested in laboratory and with Matlab. The individual blocks of the AEU, and the whole device, were tested. On the basis of these tests frequency characteristics were drawn and the quality of the audio device was analyzed. Besides acquiring expertise in hardware design, this project has broadened my knowledge on microcontroller programming and code optimization, a requirement for real time signal processing. It also gave me the opportunity to use the commercial MPLAB programming environment.
Głównym celem tej pracy magisterskiej było zaprojektowanie i zbudowanie układu do generowania efektów dźwiękowych (Audio Effects Unit - AEU) służącego do przetwarzania sygnału dźwiękowego w czasie rzeczywistym. Zadaniem autora było skonstruowanie ogólnego zastosowania układu przetwarzającego sygnał dźwiękowy, w którym funkcja przetwarzania, zaimplementowana w sposób cyfrowy, może być łatwo określona przez użytkownika poprzez zastosowanie odpowiedniego oprogramowania komputerowego. Pierwszy etap projektu polegał na szczegółowym zaprojektowaniu i zbudowaniu warstwy sprzętowej tworzącej AEU. W projekcie przewidziano tez możliwość umieszczenia układu w obudowie, co było dla autora nowym doświadczeniem projektowym. Kolejnym etapem było opracowanie algorytmów matematycznych, zaimplementowanych w mikrokontrolerze AEU, które tworzą efekty dźwiękowe poprzez przetwarzanie oryginalnego sygnału dźwiękowego. Te algorytmy zostały najpierw przetestowane w programie MatLab. Do kontrolowania wytworzonych efektów dźwiękowych, został napisany program komputerowy, który pozwala na prostą interakcje z użytkownikiem. Ten program zapewnia komunikację między mikrokontrolerem AEU i oprogramowaniem komputerowym poprzez złącze USB. Gotowe urządzenie zostało zbadane w laboratorium oraz za pomocą programu Matlab. Poszczególne bloki AEU jak i całe urządzenie zostały przetestowane, co pozwoliło na wykreślenie charakterystyk częstotliwościowych i umożliwiło analizę jakości wykonanego urządzenia audio. Oprócz zdobywania doświadczenia w projektowaniu sprzętu, udział w projekcie poszerzył moją wiedzę o programowaniu mikrokontrolerów i optymalizacji kodu, potrzebną dla przetwarzania sygnału w czasie rzeczywistym. Ponadto miałem możliwość zapoznania się z komercyjnym środowiskiem programistycznym MPLAB.
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Ahman, Danel. "Fibred computational effects." Thesis, University of Edinburgh, 2017. http://hdl.handle.net/1842/28788.
Full textAbstract:
We study the interplay between dependent types and computational effects, two important areas of modern programming language research. On the one hand, dependent types underlie proof assistants such as Coq and functional programming languages such as Agda, Idris, and F*, providing programmers a means for encoding detailed specifications of program behaviour using types. On the other hand, computational effects, such as exceptions, nondeterminism, state, I/O, probability, etc., are integral to all widely-used programming languages, ranging from imperative languages, such as C, to functional languages, such as ML and Haskell. Separately, dependent types and computational effects both come with rigorous mathematical foundations, dependent types in the effect-free setting and computational effects in the simply typed setting. Their combination, however, has received much less attention and no similarly exhaustive theory has been developed. In this thesis we address this shortcoming by providing a comprehensive treatment of the combination of these two fields, and demonstrating that they admit a mathematically elegant and natural combination. Specifically, we develop a core effectful dependently typed language, eMLTT, based on Martin-L¨of’s intensional type theory and a clear separation between (effect-free) values and (possibly effectful) computations familiar from simply typed languages such as Levy’s Call-By-Push-Value and Egger et al.’s Enriched Effect Calculus. A novel feature of our language is the computational S-type, which we use to give a uniform treatment of type-dependency in sequential composition. In addition, we define and study a class of category-theoretic models, called fibred adjunction models, that are suitable for defining a sound and complete interpretation of eMLTT. Specifically, fibred adjunction models naturally combine standard category-theoretic models of dependent types (split closed comprehension categories) with those of computational effects (adjunctions). We discuss and study various examples of these models, including a domain-theoretic model so as to extend eMLTT with general recursion. We also investigate a dependently typed generalisation of the algebraic treatment of computational effects by showing how to extend eMLTT with fibred algebraic effects and their handlers. In particular, we specify fibred algebraic effects using a dependently typed generalisation of Plotkin and Pretnar’s effect theories, enabling us to capture precise notions of computation such as state with location-dependent store types and dependently typed update monads. For handlers, we observe that their conventional term-level definition leads to unsound program equivalences becoming derivable in languages that include a notion of homomorphism, such as eMLTT. To solve this problem, we propose a novel type-based treatment of handlers via a new computation type, the user-defined algebra type, which pairs a value type (the carrier) with a family of value terms (the operations). This type internalises Plotkin and Pretnar’s insight that handlers denote algebras for a given equational theory of computational effects. We demonstrate the generality of our type-based treatment of handlers by showing that their conventional term-level presentation can be routinely derived, and this treatment provides a useful mechanism for reasoning about effectful computations. Finally, we show that these extensions of eMLTT can be soundly interpreted in a fibred adjunction model based on the families of sets fibration and models of Lawvere theories.