Dissertations / Theses on the topic 'Applications in physical sciences'
To see the other types of publications on this topic, follow the link: Applications in physical sciences.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Applications in physical sciences.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Rajotte, Matthew. "Stochastic Differential Equations and Numerical Applications." VCU Scholars Compass, 2014. http://scholarscompass.vcu.edu/etd/3383.
Full textAbstract:
We will explore the topic of stochastic differential equations (SDEs) first by developing a foundation in probability theory and It\^o calculus. Formulas are then derived to simulate these equations analytically as well as numerically. These formulas are then applied to a basic population model as well as a logistic model and the various methods are compared. Finally, we will study a model for low dose anthrax exposure which currently implements a stochastic probabilistic uptake in a deterministic differential equation, and analyze how replacing the probablistic uptake with an SDE alters the dynamics.
2
Yassin, Zakiya. "Characterization of OSTE-based polymers for acoustofluidic applications." Thesis, KTH, Tillämpad fysik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-209924.
Full text
3
Ninic, Svensson Carlo, and Berger Berg. "Characteristics and Applications of One Dimensional Single Photon LiDAR." Thesis, KTH, Skolan för teknikvetenskap (SCI), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-297814.
Full textAbstract:
A challenge when working with optics systems is identifying and locating errors and irregularities in an effective and non-time consuming manner. Getting a view of how light interacts with every individual component in a complex optical system would streamline this process. This report examines the 1D-LiDAR as a tool to use when troubleshooting optical systems. With a 1D-LiDAR setup, different scenarios of applications are investigated and possibilities as well as limitations are discussed. Experiments done on different optical setups show that alignment of optical elements play a key part of getting reliable information about optical systems. It is shown that the resolution of the LiDAR setup is nine millimeters but is dependent on the equipment used. Results show that with free access to a complex optical setup, it is possible to distinguish all elements in the system and their characteristics. Therefore it appears possible to diagnose defect optical elements. It is also shown that the LiDAR can be used to investigate temperature change in optical fibers.
4
Ninic, Svensson Carlo, and Viktor Berger. "Characteristics and Applications of One Dimensional Single Photon LiDAR." Thesis, KTH, Skolan för teknikvetenskap (SCI), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-297814.
Full textAbstract:
A challenge when working with optics systems is identifying and locating errors and irregularities in an effective and non-time consuming manner. Getting a view of how light interacts with every individual component in a complex optical system would streamline this process. This report examines the 1D-LiDAR as a tool to use when troubleshooting optical systems. With a 1D-LiDAR setup, different scenarios of applications are investigated and possibilities as well as limitations are discussed. Experiments done on different optical setups show that alignment of optical elements play a key part of getting reliable information about optical systems. It is shown that the resolution of the LiDAR setup is nine millimeters but is dependent on the equipment used. Results show that with free access to a complex optical setup, it is possible to distinguish all elements in the system and their characteristics. Therefore it appears possible to diagnose defect optical elements. It is also shown that the LiDAR can be used to investigate temperature change in optical fibers.
5
Johansson, Sara. "Evaluation of Commercial Radar Sensors for Proximity Fuze Applications." Thesis, Umeå universitet, Institutionen för fysik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-165309.
Full textAbstract:
Radar sensors has been known for their usage in military applications but during the last decade commercial radar sensors have been implemented for usage in for example advanced driver-assistance system. One common implementation for advanced driver-assistance system is the adaptive cruise control technology implemented in vehicles to help it adapt the velocity based on the distance to a detected vehicle in front. The development of the commercial radar sensors have made radar sensors cheaper and more accessible. The goal of this thesis is to investigate the civil market to see if there are any radar sensors available that could be of interest to use for applications in proximity fuzes. A proximity fuze can be used in projectiles to initiates its explosion when the projectile is positioned an optimal distance from the target where the distance can be estimated by using a radar system. Investigation of the civil market was made by performing a literature study by looking into articles about civil use applications for frequency modulated continuous wave radars and pulsed Doppler radars operating with a frequency in the GHz-area. In the literature study, five interesting frequencies were identified for the frequency modulated continuous wave radar: 24 GHz, 35 GHz, 77 GHz, 94 GHz and 122 GHz. For each article different properties regarding the sensors’ performance was investigated. Example of a few of the properties investigated was the sensor’s limitation of maximum range, angle and velocity. Based on the literature study’s result a 77 GHz radar sensor included in an evaluation kit was ordered and used to perform a proof-of-concept where the radar sensor’s performance was evaluated. The proof-of-concept was made by analyzing if the radar sensor could detect a drone at distances between 5 m and 20 m at rest or moving with a velocity of approximately 3 m/s. Two scenarios were tested for the drone and the sensor. In the first scenario, possible background clutter was eliminated while the second scenario included some background clutter. The sensor was able to detect the drone at all positions when moving or at rest, but for the second scenario there were some difficulties to get a clear detection of the target at 10 m and 20 m distance. Distance and angle measurements were performed on a metal plate having a larger radar cross section than the drone. The evaluation kit was able to detect the object at distances between 5 m and 20 m and when the object was placed 10 m away from the sensor in both x- and y-direction i.e. 45 ° from the sensor. From these results it could be concluded that radar sensors used for automotive applications has potential to be used for proximity fuze applications but further tests have to be made before a definitive conclusion can be made. The sensor has to be tested for higher velocities than 500 m/s and for larger distances to be able to determine if this type of sensor could be applied in proximity fuzes.Radarsensorer har länge använts inom militära applikationer men har på senare tid introducerats på den civila marknaden i form av exempelvis adaptiva farthållare i fordon. Radarsensorn hjälper fordonet att detektera avståndet till fordonet framför samt medför att den kan korrigera hastigheten för att hålla ett säkert avstånd och minska risken för olyckor. Utvecklingen inom den civila marknaden har lett till att radarsensorer idag är både billiga och lättillgängliga. Syftet med detta examensarbete har varit att undersöka den civila marknaden för att se om det finns någon tillgänglig radarsensor som skulle kunna användas för applikationer i zonrör. Marknaden genomsöktes genom att genomföra en litteraturstudie där artiklar innehållande information om frekvensmodulerade kontinuerlig våg radar och pulsad Doppler radar som opererar med en frekvens i GHz-området studerades. Faktorer och egenskaper som tillgänglighet, räckvidd och spridningsvinkel var några av de egenskaper som analyserades. I denna studie hittades fem intressanta frekvenser för frekvensmodulerad kontinuerlig våg radar som används inom olika applikationer på den civila marknaden, 24 GHz, 35 GHz, 77 GHz, 94 GHz och 122 GHz. Baserat på litteraturstudiens resultat beslutades att en 77 GHz radarsensor skulle utvärderas genom fysiska tester för att utvärdera radarsensorns prestanda. Först undersöktes om radarsensorn kunde detektera en drönare på avstånd upp till 20 m i en miljö med eller utan störningar i omgivningen. Tester genomfördes för drönaren när den befann sig i vila eller i rörelse med en hastighet på ungefär 3 m/s. Radarsensorn lyckades detektera testobjektet under samtliga avstånd, hastigheter och miljöer men hade vissa svårigheter att få en tydlig detektering av objektet i miljön innehållande bakgrundsstörningar. Tester genomfördes också på en metallplatta med större radarmålarea än drönaren. Radarsensorn lyckades detektera testobjektet på ett avstånd upp till 20 m och när objektet befann sig 10 m från sensorn i både x- och y-riktning d.v.s. 45 ° från utvärderingsmodulen. Utifrån dessa resultat framkom det att radarsensorer utformade för autonoma applikationer har potential att användas i zonrörs-tillämpningar men att vidare tester för längre avstånd och högre hastigheter måste genomföras innan en slutgiltig slutsats kan dras.
6
Vestberg, Robert. "Dendron decorated chromophores for optical power limiting applications." Doctoral thesis, Stockholm, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-78.
Full text
7
Myers, Jametta. "Applications of Operations Research in Domestic Electric Utilities." VCU Scholars Compass, 2008. http://scholarscompass.vcu.edu/etd/1658.
Full textAbstract:
Since its inception in the 1950s, operations research has been used in a number of industries, including the energy industry. Documentation of its use in exploration, production, gasoline blending, oil spill management, coal mining, coal handling, and coal mixing is extensive. However, considerably less documented research exists for one significant customer of many of these products: the electric utility. This work reviews refereed literature from United States operations research journals that document the use of operations research in United States electric utility operations. Applications that centered specifically on the areas of thermal energy generation, transmission, distribution, capacity planning, electric power service options, and other general operations-related activities were included. Applications solely related to plant siting, general energy policy, or work that focused on electricity as a commodity and primarily investigated the use of financial instruments, were not included.
8
Eaton, Chris. "Designing Mobile Applications Around Load-Balancing Principles to Improve Performance." Digital Commons @ East Tennessee State University, 2013. https://dc.etsu.edu/honors/142.
Full textAbstract:
Developers of mobile applications commonly delegate computations to networked resources, which have considerably more processing capacity than contemporary mobile devices. The work described here investigates an alternative approach to managing these computations, which uses a dynamic load-balancing algorithm to divide processing work between a mobile device and a back-end server.
9
Peters, Kyle C. "Sustainable Materials and Processes for Optoelectronic Applications." Case Western Reserve University School of Graduate Studies / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=case1554397264722736.
Full text
10
Crudden, D. J. "Alloys-by-design : applications to polycrystalline nickel superalloys for turbine disc applications." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:b60e1854-cae4-4dd3-8d6f-cec1351e4c17.
Full textAbstract:
The nickel-based superalloys have been a key enabler to the development of modern gas turbine engines. Since their introduction the chemical complexity of these alloys has increased significantly, with current generation nickel-based superalloys usually containing over 10 different elements. It is this combination of alloying additions that is responsible for the superior high temperature properties these alloys exhibit. Traditionally, alloy design has invoked considerable use of trial-and-error based approaches involving costly and exhaustive processing backed up by empirical property testing. In this work a computational materials design approach is developed. This method links physically-faithful composition-dependent models with thermodynamic calculations to understand material behaviour. By doing this it is possible to consider large compositional design spaces and isolate alloys expected to have optimal performance for specific applications. The scope of this research has been to apply the computational model to the design of a polycrystalline nickel-based superalloy for turbine disc applications in next generation jet engines. The design trade-offs encountered when developing the new alloy are highlighted. Alloy compositions which are predicted to be optimal for turbine disc applications are isolated. These alloys have been manufactured using a scaled down version of the commercial production method. The newly manufactured alloys have been characterised using microstructural evaluation, mechanical testing and corrosion testing. The experimental results have been compared with modelling predictions in order to determine the capability of the computational approach.
11
Wang, Haodong. "A privacy preserving framework for cyber-physical systems and its integration in real world applications." W&M ScholarWorks, 2009. https://scholarworks.wm.edu/etd/1539623552.
Full textAbstract:
A cyber-physical system (CPS) comprises of a network of processing and communication capable sensors and actuators that are pervasively embedded in the physical world. These intelligent computing elements achieve the tight combination and coordination between the logic processing and physical resources. It is envisioned that CPS will have great economic and societal impact, and alter the qualify of life like what Internet has done. This dissertation focuses on the privacy issues in current and future CPS applications. as thousands of the intelligent devices are deeply embedded in human societies, the system operations may potentially disclose the sensitive information if no privacy preserving mechanism is designed. This dissertation identifies data privacy and location privacy as the representatives to investigate the privacy problems in CPS. The data content privacy infringement occurs if the adversary can determine or partially determine the meaning of the transmitted data or the data stored in the storage. The location privacy, on the other hand, is the secrecy that a certain sensed object is associated to a specific location, the disclosure of which may endanger the sensed object. The location privacy may be compromised by the adversary through hop-by-hop traceback along the reverse direction of the message routing path. This dissertation proposes a public key based access control scheme to protect the data content privacy. Recent advances in efficient public key schemes, such as ECC, have already shown the feasibility to use public key schemes on low power devices including sensor motes. In this dissertation, an efficient public key security primitives, WM-ECC, has been implemented for TelosB and MICAz, the two major hardware platform in current sensor networks. WM-ECC achieves the best performance among the academic implementations. Based on WM-ECC, this dissertation has designed various security schemes, including pairwise key establishment, user access control and false data filtering mechanism, to protect the data content privacy. The experiments presented in this dissertation have shown that the proposed schemes are practical for real world applications. to protect the location privacy, this dissertation has considered two adversary models. For the first model in which an adversary has limited radio detection capability, the privacy-aware routing schemes are designed to slow down the adversary's traceback progress. Through theoretical analysis, this dissertation shows how to maximize the adversary's traceback time given a power consumption budget for message routing. Based on the theoretical results, this dissertation also proposes a simple and practical weighted random stride (WRS) routing scheme. The second model assumes a more powerful adversary that is able to monitor all radio communications in the network. This dissertation proposes a random schedule scheme in which each node transmits at a certain time slot in a period so that the adversary would not be able to profile the difference in communication patterns among all the nodes. Finally, this dissertation integrates the proposed privacy preserving framework into Snoogle, a sensor nodes based search engine for the physical world. Snoogle allows people to search for the physical objects in their vicinity. The previously proposed privacy preserving schemes are applied in the application to achieve the flexible and resilient privacy preserving capabilities. In addition to security and privacy, Snoogle also incorporates a number of energy saving and communication compression techniques that are carefully designed for systems composed of low-cost, low-power embedded devices. The evaluation study comprises of the real world experiments on a prototype Snoogle system and the scalability simulations.
12
Rittenhouse, Michelle L. "Properties and Recent Applications in Spectral Graph Theory." VCU Scholars Compass, 2008. http://scholarscompass.vcu.edu/etd/1126.
Full textAbstract:
There are numerous applications of mathematics, specifically spectral graph theory, within the sciences and many other fields. This paper is an exploration of recent applications of spectral graph theory, including the fields of chemistry, biology, and graph coloring. Topics such as the isomers of alkanes, the importance of eigenvalues in protein structures, and the aid that the spectra of a graph provides when coloring a graph are covered, as well as others.The key definitions and properties of graph theory are introduced. Important aspects of graphs, such as the walks and the adjacency matrix are explored. In addition, bipartite graphs are discussed along with properties that apply strictly to bipartite graphs. The main focus is on the characteristic polynomial and the eigenvalues that it produces, because most of the applications involve specific eigenvalues. For example, if isomers are organized according to their eigenvalues, a pattern comes to light. There is a parallel between the size of the eigenvalue (in comparison to the other eigenvalues) and the maximum degree of the graph. The maximum degree of the graph tells us the most carbon atoms attached to any given carbon atom within the structure. The Laplacian matrix and many of its properties are discussed at length, including the classical Matrix Tree Theorem and Cayley's Tree Theorem. Also, an alternative approach to defining the Laplacian is explored and compared to the traditional Laplacian.
13
Kannan, Balamurali. "Fabrication of surface amine gradients by controlled-rate infusion for chromatographic applications." VCU Scholars Compass, 2013. http://scholarscompass.vcu.edu/etd/533.
Full textAbstract:
Surface gradients are materials that exhibit a variation in properties such as chemical composition, topography etc., in a continuous and/or discrete fashion. They are broadly classified as chemical and physical gradients depending upon the properties that gradient exhibits. Among those, chemical gradients on various surfaces have been a great interest in materials research for the last two decades. This is due to the applications of gradients in various fields such as biological sciences, separation science, etc. There have been several different approaches developed for the preparation of chemical gradients. Silane-based approaches are among those that are widely used because of the straightforwardness of the chemistry involved and also the availability of silanes with various chemical functionalities. A few of these silane based approaches such as the vapor-diffusion method and liquid diffusion method have been used for various applications so far. Most of these methods were only able to prepare surface chemical gradients for a specific application mainly because of their limitations in terms of gradient-length scale and chemistry involved. Hence, there is a need to develop additional procedures for the preparation of chemical gradients that can be adaptable to different substrates and use them to form gradients at various length-scales such as few hundred microns to tens of centimeters. Using 3-aminopropyltriethoxysilane (APTEOS) as the precursor, a simple method was developed to prepare surface amine gradients termed ‘controlled-rate infusion (CRI). The CRI method involves the infusion of an organoalkoxysilane solution into a container with a substrate mounted vertically so that time-based exposure along the substrate forms a gradient in chemical functionality. The most important attribute of this method is that the local steepness of the gradient can be systematically controlled by simply changing the rate of infusion. The steepness of the gradient can also be changed at predefined positions along its length by programming the rate of infusion. The ability to manipulate the gradient profile is particularly important for applications that rely on mass transport and/or those that require spatial control of gradient properties. CRI can also be used to study the reactivity of aminoalkoxysilanes that contain mono, di and tri amino groups and also amines with various substitutions (secondary and tertiary amines). The gradient profiles in each case were different and correlated to their reactivity with surface silanols. Among those aminoalkoxysilanes, ethylenediamine and diethlenetriamine were found to be very good chelating agents to bind with metal ions. Thus, gradients prepared with diamine and triamine were used as ligand density gradients for the investigation of metal-amine complex formation using two different metal ions (Cu2+ and Zn2+). The above mentioned work formed the first part of this dissertation (up to Chapter 5). The latter part concentrates on fabrication and application of surface gradients for stationary phases for chromatographic separation. For the demonstration of proof-of-principle of the application of gradient stationary phases, the CRI approach was employed to prepare continuous stationary phase gradients on HP-TLC plates for planar chromatography. The SiOH groups on the activated HP-TLC plates were reacted with 3-aminopropyltriethoxysilane (APTEOS) in a time dependent fashion by using a programmable syringe pump to control the rate of APTEOS infusion into the deposition reservoir. The shape (profile) of the gradient was controlled by the rate of infusion and the gradients were visualized by utilizing a concentration-dependent color formation reaction between amine groups and ninhydrin. The advantages of such gradients in optimizing the retention and separation of various components in different mixtures was illustrated using mixtures of (i) four weak acids and bases and (ii) three widely-used over-the-counter drugs. Thus, the gradient stationary phase was successfully fabricated and applied as a planar chromatographic support. The next step of this research was to prepare continuous amine gradients on silica capillaries as these would be useful in open-tubular capillary electrochromatography for separation of complex mixtures and also to study the retention behavior of various components. This was achieved by carefully infusing micro-volumes of APTEOS solution into the activated silica capillaries. To characterize these gradients, a unique set-up was developed to measure streaming potential and zeta potential along the gradient capillary. Since surface amine groups exist as positively charged groups at acidic and neutral pHs, the measured zeta potential increased from the low amine end to the high amine end of the capillary. In summary, this dissertation work focuses mainly on the development of a simple, rapid and cost-effective method for the preparation of surface chemical gradients. CRI has incredible flexibility and adaptability, which was confirmed by extending it to different substrates such as silica TLC plates and capillary tubes for various applications. The CRI approach is not just helpful in preparing gradients for chromatographic separations; it can be a stable platform to study the reactivity of various precursors which could be a useful tool to develop high-throughput surface modification procedures.
14
Radwan, Farah. "SYNTHESIS, FUNCTIONALIZATION AND CHARACTERIZATION OF DUAL MODE NANOPARTICLES FOR BIOMEDICAL APPLICATIONS." VCU Scholars Compass, 2010. http://scholarscompass.vcu.edu/etd/2264.
Full textAbstract:
Three different approaches were used to prepare dual mode nanoparticles using a previously described reverse micelle technique. Superparamagnetic Fe@FeOx core shell nanoparticles were chosen to be the magnetic component for all three dual mode systems. In the first type of particles, 2- amino-1,3- propane diol (APD) was used as a functionalization ligand to stabilize the surface of the particles and its functional amino group also provided a binding site for the attachment of a fluorescent probe. The TEM analysis showed that the APD coated particles have a size range of 8-13 nm while XPS and MALDI measurements confirmed the presence of the APD ligand on the surface of the particles. The VSM data showed that the magnetization of the unfuntionalized particles was 60 emu/g and after functionalization the magnetization became 33 emu/g. The slight reduction magnetization was a result of the organic surface coating of APD. At this point, we realized that attaching a bulky organic fluorescent probe will cause the particles’ magnetization to further decrease. Therefore, our attention was directed towards inorganic semiconductors nanoparticles to be used as the optical component of the dual mode particles. The second approach included replacing the FeOx shell around the metallic iron core with a quantum dots shell (QDs). Thioglycerol was used to stabilize the surface of the synthesized CdS particles. The diffraction pattern of the produced particles was in agreement with the reference patterns of both alpha iron and CdS hexagonal crystal lattice, as illustrated by the XRD measurements. The TEM images of the coated particles revealed core shell morphology before the addition of thioglycerol and the particles were aggregated. After thioglycerol was added, the particles became more isolated with an approximate size of 14 nm. Optical measurements of the coated particles showed an emission peak at 670 nm using an absorbance peak of 335 nm. XPS scans verified the presence of CdS shell on the surface of the iron particles. The magnetization of the coated particles was 22 emu/ g, which is lower than that of the APD coated particles. Although, the optical properties of the dual mode system were enhanced, the magnetization was reduced. This leads to our third approach in preparing the dual mode system, we used organometallic Prussian blue compound as our optical probe. Similar to the XRD data of the CdS@Fe nanoparticles, the core consists of metallic iron for PB@Fe nanoparticles. The TEM images showed core shell morphology and approximate size of 11 nm. The attachment of PB ligand on the surface of the particles was verified using XPS and the magnetic data revealed that PB@Fe nanoparticles has the highest magnetization value of 80 emu/ g and it’s the highest in comparison to the previous two system. In conclusion, we have taken three approaches to develop magnetic and optical dual mode nanoparticles. Each system has its advantages and limitations. For instance, CdS nanoparticles have the most enhanced optical properties but the lowest magnetization. On the other hand PB@Fe has the highest magnetization saturation but not the optimal optical properties. Future work includes the improvement of both the magnetic and optical properties of these systems.
15
Hagelberg, Frank. "Electron Dynamics in Molecular Interactions: Principles and Applications." Digital Commons @ East Tennessee State University, 2014. http://amzn.com/1848164874.
Full textAbstract:
This volume provides a comprehensive introduction to the theory of electronic motion in molecular processes an increasingly relevant and rapidly expanding segment of molecular quantum dynamics. Emphasis is placed on describing and interpreting transitions between electronic states in molecules as they occur typically in cases of reactive scattering between molecules, photoexcitation or nonadiabatic coupling between electronic and nuclear degrees of freedom.
Electron Dynamics in Molecular Interactions aims at a synoptic presentation of some very recent theoretical efforts to solve the electronic problem in quantum molecular dynamics, contrasting them with more traditional schemes. The presented models are derived from their roots in basic quantum theory, their interrelations are discussed, and their characteristic applications to concrete chemical systems are outlined. This volume also includes an assessment of the present status of electron dynamics and a report on novel developments to meet the current challenges in the field.
Further, this monograph responds to a need for a systematic comparative treatise on nonadiabatic theories of quantum molecular dynamics, which are of considerably higher complexity than the more traditional adiabatic approaches and are steadily gaining in importance. This volume addresses a broad readership ranging from physics or chemistry graduate students to specialists in the field of theoretical quantum dynamics.https://dc.etsu.edu/etsu_books/1055/thumbnail.jpg
16
Oyola, Mayra I. "Implementation of a Global Dust Physical Sea Surface Temperature Retrieval For Numerical Weather Prediction Applications." Thesis, Howard University, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10188977.
Full textAbstract:
This works presents the results for the first study to ever attempt to analyze the full potential and limitations of incorporating aerosols within a truly physical SST retrieval for operational weather forecasting purposes. This is accomplished through the application of a satellite sea surface temperature (SST) physical retrieval for satellite split-window and hyperspectral infrared (IR) sensors that allows a better representation of the atmospheric state under aerosol-laden conditions. The new algorithm includes 1) accurate specification of the surface emissivity that characterizes the surface leaving radiance and 2) transmittance and physical characterization of the atmosphere by using the Community Radiative transfer model (CRTM). This project includes application of the NEMS-Global Forecasting System Aerosol Component (NGAC) fields, which corresponds to the first global interactive atmosphere-aerosol forecast system ever implemented at NOAA’s National Center for Environmental Prediction (NCEP).
A number of limiting factors were identified by analysing brightness temperatures and SST outputs biases as a function of latitude, zenith angle, wind and moisture for cases in January and November 2013. SST ouputs are validated against a bulk SST (Reynolds SST) and a parameterized SST derived from operational products and partly against observed measurements from the eastern Atlantic Ocean, which is dominated by Saharan dust throughout most of the year and that is also a genesis region for Atlantic tropical cyclones. These observations are obtained from the NOAA Aerosols and Ocean Science Expeditions (AEROSE). The improved physical SST methodology has the potential to allow for improved representation of the geophysical state under dust-laden conditions.
17
Tremblay, Louis-Bruno. "Modelling sea ice as a granular material, with applications to climate variability." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=34472.
Full textAbstract:
A new dynamic service model based on granular material rheology is presented. The service model is coupled to both a mixed-layer ocean model and a 1-layer thermodynamic atmospheric model which allows for an ice-albedo feedback. Land is represented by a 6-meter thick layer with a constant base temperature. A 10-year integration including both thermodynamic and dynamic effects and incorporating prescribed climatological wind stress and ocean current data was performed in order for the model to reach a stable periodic seasonal cycle. The commonly observed lead complexes, along which sliding and opening of adjacent ice floes occur in the Arctic sea-ice cover, are well reproduced in this simulation. In particular, shear lines extending from the western Canadian Archipelago toward the central Arctic, often observed in winter satellite images, are present. The ice edge is well positioned both in winter and summer using this thermodynamically coupled ocean-ice-atmosphere model. The results also yield a sea-ice circulation and thickness distribution over the Arctic which are in good agreement with observations. The model also produces an increase in ice formation associated with the dilatation of the ice medium along sliding lines. In this model, incident energy absorbed by the ocean melts ice laterally and warms the mixed layer, causing a smaller ice retreat in the summer. This cures a problem common to many existing thermodynamic-dynamic sea-ice models.The origin and space-time evolution of Beaufort Sea ice anomalies are studied using data and the sea-ice model described above. In particular, the influence of river runoff, atmospheric temperature and wind anomalies in creating anomalous sea ice condition in the Beaufort Sea is studied. The sea-ice model is then used to track the position of an ice anomaly as it is transported by the Beaufort Gyre and the Transpolar Drift Stream out of the Arctic Basin.
It can be inferred from driftwood data collected in the Canadian Arctic Archipelago that very different sea-ice drift patterns were present in the Arctic Ocean during the Holocene. In this study, the sea-ice model described above is used to examine the different modes of Arctic sea-ice circulation during this period, and also to infer characteristics of century-to-millennial scale changes in Arctic atmospheric circulation. (Abstract shortened by UMI.)
18
Bjürnsson, Halldór. "A coupled zonally averaged ocean sea ice atmosphere model with applications to quaternary climate variability /." Thesis, McGill University, 1997. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=34503.
Full textAbstract:
A zonally averaged coupled atmosphere-ocean model for climate studies is developed. The ocean component is the Wright and Stocker two-dimensional thermohaline circulation (THC) model, and the atmospheric component is a zonally averaged energy-moisture balance model for the atmosphere. Both single- and multi-basin configurations of the model are considered.The results obtained with this coupled model are compared with those from an ocean-only model that employs mixed boundary conditions. The differences in the steady states of the two models and their linear stability are examined over a wide range of parameters, for both one- and two-basin ocean models. The presence of additional feedbacks between the ocean circulation and the atmosphere and hydrological cycle in the coupled model produces significant differences between the latter and the ocean-only model. The two models generally have different (though similar) equilibria, but, more importantly for the issue of climate change, the variability in the models near similar steady states is quite different. These differences indicate that to perform relevant investigations of long-term climatic variability, a coupled model is necessary.
Next the coupled model with three-ocean basins is applied to last glacial maximum (LGM) conditions. It is found that to achieve realistic results, it is necessary to add a thermodynamic sea ice model into the coupled atmosphere-ocean model. The variability of the LGM conveyor circulation in the coupled ocean-sea ice-atmosphere model is then examined, and the model is subjected to a range of freshwater perturbation experiments. The conveyor state circulation is quite sensitive to the interbasin atmospheric transport of water vapour from the Atlantic to the Pacific. In particular, increasing this transport makes the conveyor state more robust. The LGM model circulation does not exhibit internal century-to-millennial scale variability, nor can the latter be excited by steady freshwater forcing. However, rapid climatic change on a timescale of decades can be generated through transient freshwater forcing of the northern North Atlantic. Perturbations in the ocean circulation are also found to propagate from the Atlantic Ocean to the Pacific Ocean in a few decades. Stochastic, white noise forcing of the model results in a mainly red noise response but also excites a natural mode of THC variability with a timescale of about 150 years.
19
Sønderby, Steffen. "Physical Vapor Deposition of Yttria-Stabilized Zirconia and Gadolinia-Doped Ceria Thin Films for Fuel Cell Applications." Licentiate thesis, Linköpings universitet, Tunnfilmsfysik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-84611.
Full textAbstract:
In this thesis, reactive sputter deposition of yttria-stabilized zirconia (YSZ) and cerium gadolinium oxide (CGO) thin films for solid oxide fuel cell (SOFC) applications have been studied. All films have been deposited under industrial conditions. YSZ films were deposited on silicon wafers as well as commercial NiO-YSZ fuel cell anodes. The texture, morphology, and composition of the deposited films were investigated with respect to deposition parameters such as bias voltage which was identified as a key parameter to tailor the texture of the film and promote less columnar coatings when depositing on Si. In contrast, films grown on NiO-YSZ fuel cell anodes were seen to be randomly orientated when deposited at low substrate bias voltages. When the bias voltage was increased the film took over the orientation of underlying substrate due to substrate template effects. The deposited coatings were found to be homogeneous large areas within the coating zone, which is highly important for industrial applications. The performance of sputtered CGO thin films as diffusion barriers for stopping Sr diffusion between SOFC cathodes and electrolytes was also studied. This was done by introducing the sputtered CGO films in a metal-based SOFC setup. The performance depended on the density of the barrier layer, signifying that Sr diffusion and SrZrO3 formation is an issue. Area specific resistances down to 0.27 Ωcm2, corresponding to a maximum power density up to 1.14 W cm−2 at 650 °C could be obtained with sputtered CGO barrier layers in combination with Sr-doped lanthanum cobalt oxide cathodes which is a significant improvement compared conventional ceramic SOFCs. The diffusion mechanism of Sr through sputtered CGO films was investigated. For this purpose, a model system simulating a SOFC was prepared by depositing CGO and YSZ on cathode material. This setup allowed observation of Sr diffusion by observing SrZrO3 formation using X-ray diffraction while annealing. Electron microscopy was subsequently performed to confirm the results. It was found that Sr diffused along column/grain boundaries in the CGO films but by modifying the film thickness and microstructure the breaking temperature of the barrier could be increased.
20
Scott, Daniel F. "DEVELOPMENT OF LUMINESCENT SENSING SYSTEMS WITH CLINICAL APPLICATIONS." UKnowledge, 2011. http://uknowledge.uky.edu/gradschool_diss/184.
Full textAbstract:
As the move towards the miniaturization of many diagnostic and detection systems continues, the need for increasingly versatile yet sensitive labels for use in these systems also grows. Luminescent reporters provide us with a solution to many of the issues at hand through their unique and favorable characteristics. Bioluminescent proteins offer detection at extremely low concentrations and no interference from physiological fluids leading to excellent detection limits, while the vast number of fluorescent proteins and molecules available allows the opportunity to select a tailored reporter for a specific task. Both provide relatively simply instrumentation requirements and have exhibited great promise with many of the miniaturized systems such as lab-on-a-chip and lab-on-a-CD designs. Herein, we describe the novel employment of luminescent reporters for four distinct purposes. First off, by combining both time and wavelength resolution we have expanded the multiplexing capabilities of the photoprotein aequorin beyond duel-analytes, demonstrating the ability to simultaneously detect three separate analytes. Three semi-synthetic aequorin proteins were genetically conjugated to three pro-inflammatory cytokines (interleukins 1, 6, and 8) resulting in aequorin labeled cytokines with differing emission maxima and half lives to allow for the simultaneous detection of all three in a single solution through the elevated physiological concentration range. Secondly a semi-synthetic aequorin variant has been genetically enhanced to serve as an immunolabel and exhibited the ability to sensitively detect the acute myeloid leukemia marker, CD33, down to the attomole level in addition to improving aequorin imaging capabilities. In the third example, the aequorin complex was rationally, genetically split into two parts and attached to the termini of the cAMP selective cAMP receptor protein (CRP) creating a genetically fused molecular switch. The conformational change experienced by CRP upon the binding of cAMP translates into a loss of bioluminescent signal from aequorin and has shown the ability to respond linearly to cAMP over several orders of magnitude. Lastly, through custom design, a reagentless, portable, fluorescent fiber optic detection system has been developed, capable of being integrated into the body through a heart catheter. The system was able to respond to changes in potassium concentration selectively, reproducibly and reversibly with a fast response time of one minute.
21
Nagler, Pamela Lynn. "Remote sensing applications: Environmental assessment of the Colorado River delta in Mexico." Diss., The University of Arizona, 2001. http://hdl.handle.net/10150/279882.
Full textAbstract:
The extent of revegetation in the Colorado River delta in Mexico is described, with emphasis on the return of native cottonwood (Populus fremontii ) and willow (Salix gooddingii) trees. Low-level aerial and satellite remote sensing methods were combined with ground surveys to census the vegetation in a 100 km reach of riparian corridor in Mexico. Although the invasive plant, saltcedar (Tamarix ramosissima), still dominates the riparian zone, native trees now account for 23% of the vegetation in the delta. Multi-band digital camera images obtained by aircraft were used to calculate the Normalized Difference Vegetation Index (NDVI) and scored for percent vegetation cover (NDVI:%C has r = 0.91***). A Thematic Mapper (TM) image taken concurrently with the aerial survey was similarly classified, and by comparing scenes on the TM and aerials, it was possible to calibrate NDVI with percent vegetation on the TM image. This information was used to conduct a change analysis relating flows in the Colorado River with summer vegetation patterns on TM images for the years 1992-1999. The results support the importance of pulse floods in restoring the ecological integrity of arid-zone rivers. This dissertation also compared transpiration rates of three Sonoran Desert riparian trees using sap flow and leaf temperature methods using constructed canopies (two of each species: Populus fremontii (cottonwood), Salix gooddingii (willow) and Tamarix ramosissima (saltcedar)) in an outdoor experiment in Tucson, Arizona. Canopies were measured over 11 days for both sap flow and canopy and air temperature differential (Tc-Ta) under non stressed and stressed conditions. Objective 1: to determine the strength of the relationship between transpiration (Et) and Tc-Ta to determine if Tc-Ta can be a useful remote sensing method to measure Et for these species. Objective 2: to compare Et rates among species, to determine if the invasive species, saltcedar, has higher Et rates or ecophysiological advantages over the native trees species. We conclude that the Tc-Ta method could be useful in estimating Et by remote sensing over riparian corridors, and that native trees are not at an ecophysiological disadvantage to saltcedar so long as sufficient non-saline soil moisture is available to support Et.
22
Parker, Lonnie Thomas. "Science-centric sampling approaches of geo-physical environments for realistic robot navigation." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/44813.
Full textAbstract:
The objective of this research effort is to provide a methodology for assessing the effectiveness of sampling techniques used to gather different types of geo-physical information by a robotic agent. We focus on assessing how well unique real-time sampling strategies acquire information that is, otherwise, too dangerous or costly to
collect by human scientists. Traditional sampling strategies and informed search tech-
niques provide the underlying structure for a navigating robotic surveyor whose goal is to collect samples that yield an accurate representation of the measured phenomena under realistic constraints. These sampling strategies are alternative improvements that provide greater information gain than current sampling technology allows. The contributions of this work include the following: 1) A method for estimating spa-
tially distributed phenomena, using a partial sample set of information, that shows improvement over that of a more traditional estimation method. 2) A method for sampling this phenomena in the form of a navigation scheme for a mobile robotic survey system. 3) A method of ranking and comparing different navigation algorithms relative to one another based on performance (reconstruction error) and resource (distance) constraints. We introduce a specific class of navigation algorithms as example sampling strategies to demonstrate how our methodology allows different robot navigation options to be contrasted and the most practical strategy selected.
23
Warren, Christopher. "Synthesis, Characterization, and Functionalization of Magnetic Iron Nanoparticles for Enhanced Biological Applications." VCU Scholars Compass, 2013. http://scholarscompass.vcu.edu/etd/3283.
Full textAbstract:
The transition metal ferrites of composition MFe2O4 where M is Fe, Co, or Ni are well established materials for various biological applications due to their interesting magnetic properties. Their elemental and stochiometric composition can be easily manipulated which allows further tuning of their ferrimagnetic properties. By changing the identity of M and by changing the crystallite size of the ferrites, nanocrystals with diverse magnetic properties can be systematically produced. Furthermore, ferrites are more stable in diverse chemical environments, as compared to metallic nanoparticles, which make ferrites particularly useful for a broad range of biomedical applications, especially in the field of magnetic resonance imaging and cell labeling. In this work, spinel ferrites of composition CoFe2O4, NiFe2O4, and Ni.5Co.5 Fe2O4 were synthesized by a polyol method utilizing ethylene glycol as the solvent, reducing agent, and surfactant. The nanoparticles produced were surface coated with 3-aminopropyltriethoxy silane to increase solubility as well as to serve as an anchor for further conjugation with targeting substrates such as peptides and antibodies. The first part of this dissertation was focused on using the polyol method to produce nanoparticles of various metallic compositions. In each case, the polyol method provided an easy one-pot method to produce metallic as well as metal oxide nanocrystals. Utilizing the polyol method, ferrites of CoFe2O4, NiFe2O4, and Ni.5Co.5 Fe2O4 were produced with size ranges between 20 nm and 50 nm depending on the reaction time in the polyol. The second part of this dissertation was concerned with the functionalization of the nanoparticles to serve as an anchor for further conjugation with targeting substrates in the immunoaffinity separation of food borne pathogens. These nanoparticles were functionalized using an anti-E. coli O157:H7 antibody, mixed with a food matrix, and then subsequently removed from the food matrix by an external magnet in order to be analyzed by Matrix Assisted Laser Desorption Ionization/Time of Flight (MALDI/TOF) Mass Spectrometry as a rapid identification method of bacterial pathogens. Furthermore, magnetic resonance imaging (MRI) was carried out on the polyol produced ferrites in order to measure the transverse relaxation time (T2) of the nanoparticles in order to investigate the size dependence and crystallite composition of the particles ability to affect the transverse relaxivity rarte (r2). Further understanding of how ferrite composition and crystallite size affect their magnetic properties and resulting MRI contrast abilities will provide insight into the best materials for the next generation of contrast agents. Lastly, the ability of nanoparticles to serve as a stationary phase material for reversed phase ultrahigh pressure liquid chromatography will be discussed as a novel separation technique.
24
Cheng, Cheng. "Semiconductor colloidal quantum dots for photovoltaic applications." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:07baccd0-2098-4306-8a9a-49160ec6a15a.
Full textAbstract:
This thesis studies lead suphide (PbS) colloidal quantum dots and their photovoltaic applications. Different sizes of PbS QDs were synthesised and characterised using absorption spectroscopy and transmission electron microscopes. PbS QD Schottky junction devices were fabricated with AM1.5 power conversion efficiency up to 1.8 %. The Schottky junction geometry limits the device performance. A semiconductor heterojunction using ZnO as an electron acceptor was built and the device efficiency increased to 3%. By studying the light absorption and charge extraction profile of the bilayer device, the absorber layer has a charge extraction dead zone which is beyond the reach of the built-in electric field. Therefore, strategies to create a QD bulk heterojunction were considered to address this issue by distributing the junction interface throughout the absorber layer. However, the charge separation mechanism of the QD heterojunction is not clearly understood: whether it operates as an excitonic or a depleted p-n junction, as the junction operating mechanism determines the scale of phase separation in the bulk morphology. This study shows a transitional behaviour of the PbS/ZnO heterojunction from excitonic to depletion by increasing the doping density of ZnO. To utilise the excitonic mechanism, a PbS/ZnO nanocrystal bulk heterojunction was created by blending the two nanocrystals in solution such that a large interface between the two materials could facilitate fast exciton dissociation. However, the devices show poor performance due to a coarse morphology and formation of germinate pairs. To create a bulk heterojunction where a built-in electric field could assist the charge separation, a TiO2 porous structure with the pore size matching with the depletion width was fabricated and successfully in-filled by PbS QDs. The porous device produces 5.7% power conversion efficiency, among one of the highest in literature. The enhancement comes from increased light absorption and suppression of charge recombination.
25
Walker, Ann L. (Ann Lee). "Strategic Planning Applications in Postsecondary Institutions with Accredited Physical Therapy Educational Programs." Thesis, University of North Texas, 1990. https://digital.library.unt.edu/ark:/67531/metadc331640/.
Full textAbstract:
Although strategic planning has been used successfully in most major business institutions, higher education has been slow to adopt this management technique. Involvement in planning is a critical issue for allied health educational programs, such as physical therapy, which are relatively new to the academic environment. These programs face a continual need to update their curricula and clinical education based on rapid changes in the health care delivery system and the profession. The problem of this study was to determine the extent to which the strategic planning process is currently applied in institutions in the United States which offer accredited physical therapy educational programs.
The population of this study was made up of the chief executive officers of the 115 public and independent institutions that offer physical therapy educational programs. Selected experts on strategic planning and chief executive officers were surveyed in two phases using a mailed questionnaire designed to measure the organization, characteristics, and impact of strategic planning in institutions that offer accredited physical therapy educational programs. Seventy-three percent of the chief executive officers responded, and 50.9 percent indicated their involvement with strategic planning by completing the questionnaire.
The findings indicate that, although there is general agreement between the experts and the chief executive officers concerning the characteristics of strategic planning, differences exist. Differences were also identified between academic health centers and other types of institutions, between public and independent institutions, and between institutions by type of physical therapy degree offered. It was concluded that, in the opinion of the chief executive officers, strategic planning processes are being practiced in institutions that offer physical therapy programs, that this process is compatible with academic collegiality, that changes are made in policies and programs but not in the mission, that although faculty members including those from physical therapy are involved, the role and the involvement of these individuals is unclear, and that information-gathering and evaluation methods could be refined.
26
Wray, John. "INVESTIGATING THE POTENTIAL APPLICATIONS OF A RAMAN TWEEZER SYSTEM." VCU Scholars Compass, 2013. http://scholarscompass.vcu.edu/etd/3135.
Full textAbstract:
This thesis describes the construction of an Optical Tweezer apparatus to be used in conjunction with a confocal Raman spectrometer. The tweezer utilizes an infrared (λ=1064 nm) laser directed into an inverted microscope with NA=1.4 oil immersion 100x objective lens that strongly focuses the laser light into a sample to function as a single-beam gradient force trap. The long term goal of this research program is to develop a single molecule Raman tweezers apparatus that allows one to control the position of a Raman nanoplasmonic amplifier. This thesis describes the construction of the Raman tweezer apparatus along with several Raman spectra obtained from optically trapped samples of polystyrene fluorescent orange, amine-modified latex beads. In addition, I explored the Raman spectra of bulk cytochrome c mixed with or injected onto Ag aggregates for SERs enhancement.
27
Jackson, Gregory M. "A Test Suite Generator For Struts Based Applications." UNF Digital Commons, 2004. http://digitalcommons.unf.edu/etd/294.
Full textAbstract:
Testing web-based enterprise applications requires the use of automated testing frameworks. The testing framework's ability to run suites of test cases through development ensures enhancements work as required and have not caused defects in previously developed sub systems. Open source testing frameworks like JUnit and Cactus have addressed the requirements to test web-based enterprise applications, however they do not address the generation of test cases based on direct analysis of the code under test.
This paper presents a tool to generate test cases for web-based enterprise applications. The generator focuses on creating test cases used to test applications built on the Struts MVC framework for the J2EE platform. Using the Struts configuration files, test cases are generated to test each request path and response. The created test cases take advantage of the StrutsTestCase library and run using the JUnit and Cactus frameworks. The generated test cases follow a consistent pattern for the test cases and reduce the time required build the automated testing for the application.
28
Gingell, Alexander David. "Applications of Coulomb crystals in cold chemistry." Thesis, University of Oxford, 2010. http://ora.ox.ac.uk/objects/uuid:3b93832d-b9eb-49e1-b4a4-1bb43d7c9c00.
Full textAbstract:
This thesis describes the study of a range of ion-molecule reactions at very low collision energies using a newly developed experimental technique which involves the reaction of velocity-selected beams of translationally cold neutral molecules with very low kinetic energy ion ensembles. These studies have been enabled by the construction of a new apparatus for trapping and laser-cooling gas phase atomic ions (40Ca⁺). The laser-cooling process results in the formation of ordered, low kinetic energy, lattice-like ion structures, also known as "Coulomb crystals". The properties of single and multicomponent Coulomb crystals (which may also involve molecular ions), and their manipulation via modulation of the applied fields, are explored experimentally and with the use of molecular dynamics simulations. Variations in the laser-cooling parameters are shown to result in different steady-state populations of the electronic states of 40Ca⁺ involved with the laser cooling cycle, and these are modelled within an appropriate theoretical framework. The imaging of 40Ca⁺ fluorescence as a function of time allows the study of various ion-molecule reactions at collision energies around 300 K, with single ion sensitivity. These reaction studies are extended to low-temperature (collision energies close to 1 K), by combination of the ion trap apparatus with a bent quadrupole guide velocity-selector. Ion-molecule collision energies are shown to be variable over a short range through a change in the quadrupole guide voltage, or the ion trapping parameters; the effect of these modulations on the rate constant is explored for Ca⁺ + CH₃F. Bimolecular rate constants for the reactions of 40Ca⁺ with CH₃F, CH₂F₂ and CH₃Cl have been determined for a range of 40Ca⁺ state populations, allowing resolution of the global rate contributions from the ground and combined excited states. These results are analysed in the context of capture theories and ab initio electronic structure calculations. In each case, suppression of the ground state rate constant is explained by the presence of either a submerged or real barrier on the ground state potential surface. Rates of reaction from the combined excited states are generally found to be in line with capture theories, and in some cases variation is found between the high and low collision energy regimes. Molecular product ions generated in these experiments have been shown to be sympathetically-cooled into the crystal structure, and subsequently identified through resonance-excitation mass spectrometry. Molecular ions were also produced by multiphoton laser ionisation of a thermal background gas of OCS molecules. An ion-molecule reaction involving a molecular ion, that of charge transfer between OCS⁺ and ND₃, has been studied at a collision energy near 1 K for the first time using sympathetically-cooled OCS⁺ and velocity-selected ND₃. These experiments illustrate the generality of the techniques described herein, and should lead to many possibilities for future studies.
29
Yates, Phillip. "An Inferential Framework for Network Hypothesis Tests: With Applications to Biological Networks." VCU Scholars Compass, 2010. http://scholarscompass.vcu.edu/etd/2200.
Full textAbstract:
The analysis of weighted co-expression gene sets is gaining momentum in systems biology. In addition to substantial research directed toward inferring co-expression networks on the basis of microarray/high-throughput sequencing data, inferential methods are being developed to compare gene networks across one or more phenotypes. Common gene set hypothesis testing procedures are mostly confined to comparing average gene/node transcription levels between one or more groups and make limited use of additional network features, e.g., edges induced by significant partial correlations. Ignoring the gene set architecture disregards relevant network topological comparisons and can result in familiar n
30
Stelljes, Scott. "Applications of Stochastic Calculus to Finance." UNF Digital Commons, 2004. http://digitalcommons.unf.edu/etd/267.
Full textAbstract:
Stochastic Calculus has been applied to the problem of pricing financial derivatives since 1973 when Black and Scholes published their famous paper "The Pricing of Options and Corporate Liabilities" in the Joumal of Political Economy. The purpose of this thesis is to show the mathematical principles underlying the methods applied to finance and to present a new model of the stock price process.
As part of this paper, we present proofs of Ito's Formula and Girsanov's Theorem which are frequently used in financial applications. We demonstrate the application of these theorems to calculating the fair price of a European call option. There are two methods that result in the same price: the risk neutral valuation and the Black-Scholes partial differential equation.
A new model of the stock price process is presented in Section 4. This model was inspired by the model of Cox and Ross published in 1976. We develop the model such that a martingale measure will exist for the present value of the stock price. We fit data to the traditional geometric Brownian motion model and the new model and compare the resulting prices. The data fit some stocks well, but in some cases the new model provided a better fit. The price of a European call is calculated for both models for several different stocks.
31
Samanta, Devleena. "UNCONVENTIONAL SUPERHALOGENS: DESIGN AND APPLICATIONS." VCU Scholars Compass, 2012. http://scholarscompass.vcu.edu/etd/2844.
Full textAbstract:
Electron affinity is one of the most important parameters that guide chemical reactivity. Halogens have the highest electron affinities among all elements. A class of molecules called superhalogens has electron affinities even greater than that of Cl, the element with the largest electron affinity (3.62 eV). Traditionally, these are metal-halogen complexes which need one electron to close their electronic shell. Superhalogens have been known to chemistry for the past 30 years and all superhalogens investigated in this period are either based on the 8-electron rule or the 18-electron rule. In this work, we have studied two classes of unconventional superhalogens: borane-based superhalogens designed using the Wade-Mingo’s rule that describes the stability of closo-boranes, and pseudohalogen based superhalogens. In addition, we have shown that superhalogens can be utilized to build hyperhalogens, which have electron affinities exceeding that of the constituent superhalogens, and also to stabilize unusually high oxidation states of metals.
32
Adams, Jonathan. "Database Auto Awesome: Enhancing Database-Centric Web Applications through Informed Code Generation." DigitalCommons@USU, 2017. https://digitalcommons.usu.edu/etd/6265.
Full textAbstract:
Database Auto Awesome is an approach to enhancing web applications comprised of forms used to interact with stored information. It was inspired by Google's Auto Awesome tool, which provides automatic enhancements for photos. Database Auto Awesome aims to automatically or semi-automatically provide improvements to an application by expanding the functionality of the application and improving the existing code.
This thesis describes a tool that gathers information from the application and provides details on how the parts of the application work together. This information provides the details necessary to generate new portions of an application.
These enhancements are directed by the web application administrator through specifying what they would like to have generated, in terms of functionality. Once the administrator has provided this direction, the new application code is generated and put in updated or new files. Using this approach, Database Auto Awesome provides a viable solution for semi-automatically generating enhancements to an existing web application.
33
Mawk, Russell Lynn. "A survey of applications of spline functions to statistics." [Johnson City, Tenn. : East Tennessee State University], 2001. http://etd-submit.etsu.edu/etd/theses/available/etd-0714101-104229/restricted/mawksr0809.pdf.
Full text
34
Ghanbarian-Alavijeh, Behzad. "Modeling Physical and Hydraulic Properties of Disordered Porous Media: Applications from Percolation Theory and Fractal Geometry." Wright State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=wright1401380554.
Full text
35
Denison, Michael Hunter. "Image Source Modeling of Time Reversal for Room Acoustics Applications." BYU ScholarsArchive, 2018. https://scholarsarchive.byu.edu/etd/7449.
Full textAbstract:
Time Reversal (TR) is a technique that may be used to focus an acoustic signal at a particular point in space. While many variables contribute to the quality of TR focusing of sound in a particular room, the most important have been shown to be the number of sound sources, signal bandwidth and absorption properties of the medium [Ribay et al., J. Acoust. Soc. Am. 117(5), 2866-2872 (2005)]. However, the effect of room size on TR focusing has not been explored. Using the image source method algorithm proposed by Allen and Berkley [J. Allen and D. A. Berkley, J. Acoust. Soc. Am. 65(4), 943-950 (1979)], TR focusing was simulated in a variety of rooms with different absorption and volume properties. Experiments are also conducted in a couple rooms to verify the simulations. The maximum focal amplitude, the temporal focus quality, and the spatial focus clarity are defined and calculated for each simulation. The results are used to determine the effects of absorption and room volume on TR. Less absorption increases the amplitude of the focusing and spatial clarity while decreasing temporal quality. Dissimilarly, larger volumes decrease focal amplitude and spatial clarity while increasing temporal quality. This thesis also explores the placement of individual transducers within a room. It also compares the layout of several source transducers used for a reciprocal time reversal process. Maximum focal amplitude and spatial clarity are found to increase when the focus location is dual coplanar to the source location while temporal quality is found to decrease in comparison to the case when source and focal location share only one plane. Maximum focal amplitude is found to be at a minimum when the focus location is at the critical distance and increases closer and farther away from the source, while temporal quality steadily decreases and spatial clarity steadily increases farther from the source. The maximum focal amplitude and the temporal quality are not greatly affected by the type of array layout, but a circular array is ideal for maximizing spatial clarity.
36
Wang, Jing. "Novel Carbon Nanotube Sol-Gel Composite for Sensing Applications." Digital Commons @ East Tennessee State University, 2006. https://dc.etsu.edu/etd/2241.
Full textAbstract:
Sol-Gel techniques depend on the hydrolysis and condensation reactions of organosilicon precursors in aqueous media and, thus, provide an inclusive environment with bioaffinity. On the other hand, carbon nanotubes (CNTs), which possess unique electric, thermal, mechanical, and chemical properties, including their high surface area:volume ratio, can be further surface-functionalized to address different material or sensing demands.
In this work we describe a new composite material that combines the unique sol-gel network with conductive CNTs. Hydrolysis and subsequent condensation of tetramethyloxysilane (TMOS) in the presence of CNTs result in the formation of a dense, homogeneous material. Properties of this composite material on electrode surfaces are discussed and novel sensing applications are described.
37
Jons, Mattias. "Doped 3C-SiC Towards Solar Cell Applications." Thesis, Linköpings universitet, Halvledarmaterial, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-148595.
Full textAbstract:
The market for renewable energy sources, and solar cells in particular is growing year by year, as a result there is a large interest in research on new materials and new technologies for solar power applications. In this thesis the photovoltaic properties of cubic silicon carbide (3C-SiC) has been investigated. The research includes material growth using the sublimation epitaxy method, both n-type and p-type SiC have been investigated. 3C-SiC pn junctions have been produced and their electrical properties have been characterized, this is the first time 3C-SiC pn junctions have been studied in the research group. Photoresponse has been demonstrated from a 3C-SiC pn junction with Al and N used as p- and ntype dopants. This is the first demonstrated solar cell performance using 3C-SiC, to our knowledge.
38
Barker, Jolene. "APPLICATIONS OF THE BIVARIATE GAMMA DISTRIBUTION IN NUTRITIONAL EPIDEMIOLOGY AND MEDICAL PHYSICS." VCU Scholars Compass, 2008. http://scholarscompass.vcu.edu/etd/1623.
Full textAbstract:
In this thesis the utility of a bivariate gamma distribution is explored. In the field of nutritional epidemiology a nutrition density transformation is used to reduce collinearity. This phenomenon will be shown to result due to the independent variables following a bivariate gamma model. In the field of radiation oncology paired comparison of variances is often performed. The bivariate gamma model is also appropriate for fitting correlated variances. A method for simulating bivariate gamma random variables is presented. This method is used to generate data from several bivariate gamma models and the asymptotic properties of a test statistic, suggested for the radiation oncology application, is studied.
39
Davis, Brian Lafayette. "Subword Spotting and Its Applications." BYU ScholarsArchive, 2018. https://scholarsarchive.byu.edu/etd/7058.
Full textAbstract:
We propose subword spotting, a generalization of word spotting where the search is for groups of characters within words. We present a method for performing subword spotting based on state-of-the-art word spotting techniques and evaluate its performance at three granularitires (unigrams, bigrams and trigrams) on two datasets. We demonstrate three applications of subword spotting, though others may exist. The first is assisting human transcribers identify unrecognized characters by locating them in other words. The second is searching for suffixes directly in word images (suffix spotting). And the third is computer assisted transcription (semi-automated transcription). We investigate several variations of computer assisted transcription using subword spotting, but none achieve transcription speeds above manual transcription. We investigate the causes.
40
Bauer, Thomas. "Thermophotovoltaic applications in the UK : critical aspects of system design." Thesis, Northumbria University, 2006. http://nrl.northumbria.ac.uk/82/.
Full textAbstract:
Almost 50 years of thermophotovoltaic (TPV) research from various sectors has resulted in a variety of potential applications and TPV technology options. In this work the potential of commercial TPV applications is assessed with specific reference to the UK. The assessment considers competing technologies for electricity generation, namely solar photovoltaics, external and internal heat engine generators, electro¬chemical cells and direct heat-to-electricity conversion devices. Electricity generation by TPV conversion from waste heat of industrial high-temperature processes is identified as one of the most suitable TPV applications. This market is examined in more detail using three specific high-temperature processes from the iron and steel and the glass sectors. Results are extrapolated to the entire UK high-temperature industry and include potential energy and CO2 savings. This work gathers knowledge from TPV and other literature sources and evaluates the technological options for the heat source, the radiator and the PV cell for a TPV system. The optical control in terms of the angular, spatial and in particular spectral radiation distributions in cavities is identified as a specific factor for TPV conversion and critical for a system design. The impact of simultaneous radiation suppression above and below the PV cell bandgap on an ultimate efficiency level is examined. This research focuses on fused silica (SiO2) in TPV cavities and examines the aspects of radiation guidance by total internal reflection and spectral control using coupled radiative and conductive heat transfer. Finite volume modelling and experimental work have examined the radiator-glass-air-PV cell arrangement up to a SiO2 thickness of 20 cm. Both show that the efficiency improves for an increased SiO2 thickness. Finally, the novel concept of a TPV cavity consisting of a solid dielectric medium is assessed.
41
Tonvall, Daniel. "Study of reflective and polarization properties of objects found in automotive LiDAR applications." Thesis, Umeå universitet, Institutionen för fysik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-173469.
Full textAbstract:
In the development of autonomous vehicles, replacing the driver and its perceptive abilities is one of many technical challenges. As a part in solving these challenges, Light Detection And Ranging (LiDAR) is a promising technology. In short, LiDAR works by using lasers to detect objects in its vicinity by detecting the light that reflects on them. With knowledge of the reflective properties of an object, a prediction can be made regarding whether a certain LiDAR unit will be able to detect the object or not. When making this prediction, the common description of reflectance is often insufficient. Instead, a more complete description is given by the Bidirectional Reflectance Distribution Function (BRDF) of a surface, which describes reflection on the surface while taking the incident and reflected direction into consideration. In this thesis, an experimental setup was built with the capabilities of measuring the BRDF while taking incident and reflected polarization into account. Program software was written in Python and integrated with the hardware, providing a user interface for simple control of the setup. The BRDF was measured on a total of 6 samples; 2 reference samples and 4 samples taken from the hood of 4 different cars. Conclusively, the setup provided useful information about the reflective and polarization properties of the samples. These measurements can help in predicting whether or not a surface can be detected by a given LiDAR unit, and can also be helpful when designing new LiDAR units by providing useful information about the surfaces they are required to detect.
42
Vilasur, Swaminathan Rohith. "Vortices in sinusoidal shear, with applications to Jupiter." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/104600.
Full textAbstract:
Thesis: S.M., Joint Program in Physical Oceanography (Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), 2016.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 97-99).
In this thesis, we have studied the existence of vortex steady states in a sinusoidal background shear flow in a 1.75 layer quasi-geostrophic model. Trying to find vortex structures by integrating the Hamiltonian system has the drawback that the vortices lose enstrophy by filamentation and numerical dissipation, while continuing to deform and wobble. Adopting the local optimization technique of Hamiltonian Dirac Simulated Annealing overcomes this drawback and allows us to obtain steady/quasi-steady vortices that have roughly the same area as that of the initial vortex. The steady states that we have generated range from elliptical with major axis aligned with the flow in the prograde shear region to triangular at the latitude where prograde and adverse shear meet and back to elliptical but with the major axis aligned perpendicular to the shear flow at the center of the adverse shear region. The steady states calculated by the above technique can be used for further analysis and as an initial condition to study the merger of vortices in background shear. This result is directly applicable to the kind of dynamics visible on planets like Jupiter, where vortices residing in zonal shear are a common occurrence.
by Rohith Vilasur Swaminathan.
S.M.
43
Walker, Richard James. "Quantum cascade laser spectroscopy : developments and applications." Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:5021ac50-c69d-4a1d-8071-e59ffed9fcb8.
Full textAbstract:
This thesis presents work examining the characteristics and applicability of quantum cascade lasers. An introduction is given explaining both the desire for a widely tunable, narrow bandwidth device working in the midinfrared, as well as detailing the ways in which quantum cascade lasers (QCLs) fulfill these requirements. The development and manufacture of QCLs are then discussed. The experimental section of this thesis is then split into three parts. Chapter 2 concerns the characterisation and application of several pulsed QCLs. The intrapulse mode of operation is employed and the effect of the resulting rapid frequency chirp upon molecular spectra is investigated in the form of rapid passage signals. The evolution of said rapid passage signals is then investigated as a function of chromophore pressure and identity, with different QCLs, chirp rates, and optical path lengths. The prospect of producing population transfer with chirped lasers is discussed. Chapters 3, 4, and 5 are then concerned with the application and characterisation of continuous wave QCLs. In these chapters a widely tunable commercially produced EC-QCL is utilised as well as two DFB QCLs, one of which is used in tandem with a home-made mount and temperature controller. In Chapter 3 a number of sensitive detection techniques are compared with the employment of wavelength modulation spectroscopy, long path cells and optical cavities, and the narrow bandwidth of QCLs utilised to determine a previously unknown spectral constant of DBr. Chapters 4 and 5 then utilise the high power of an external cavity quantum cascade laser in sub-Doppler Lamb-dip and polarisation spectroscopy measurements and then a pump-probe experiment. The laser linewidth is investigated on a millisecond timescale returning a current noise limited value of c.a. 2 MHz and the fundamental linewidth of the device investigated by altering the injection current. Chapter 5 is concerned with the pump-probe experiment, directly measuring the hot band absorption in a ladder like transition (R(6.5)$_\frac{1}{2}$ $v=1\leftarrow0$ and P(7.5)$_\frac{1}{2}$ $v=1\leftarrow0$). The Bennett peak in the hot band is observed with a DFB-QCL swept at $\sim 0.15$ MHz ns$^{-1}$ and is seen not just as a pump bandwidth limited lineshape, but as a highly velocity selected rapid passage signal. The effect of pressure, pump and probe scan rate and power upon this rapid passage signal is also studied. It is further noted that rapid thermalisation occurs within $v=1$ such that at pressures above c.a. 30 mTorr a broad NO doublet absorption is observed beneath the Bennett peak from which a total population transfer of c.a. $16 \%$ can be estimated. Finally an experiment is discussed in which this population transfer could be increased for use in secondary applications. Chapter 6 then presents initial measurements with two prototype pulsed 3.3 \si{\micro\metre} QCLs considering the prospects of such devices. A Fabry-P\'rot device is first studied using a Fourier transform spectrometer and temperature tuning used to produce a spectrum of the Q-branch of CH$_4$ around 3025 cm$^$. Experiments are then performed using a DFB QCL investigating the chirp rate of the system as an indicator of the rate of heat accumulation within the system. Heat management is of particular consideration when the sea-change is made from pulsed to continuous devices. For this device absorption spectra of two CH$_4$ transitions at 2971 cm$^$ are used to determine the chirp rate, which is found to be c.a. 1.8 GHz ns$^$, at least an order of magnitude higher than that of the longer wavelength pulsed devices considered in Chapter 2.
44
Sevy, Clément. "AI in Simulated 3D Environments : Application to Cyber-Physical systems." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-251318.
Full textAbstract:
Over the past several years, UAVs (unmanned aerial vehicles) and autonomous systems in general, have become hot topics, both in academia and in industry. Indeed, the opportunities for the application of such technologies are vast, with the military and the infrastructure industry being the two most eminent cases. Up until recently, autonomous systems showed quite little flexibility, their actions originating in well-defined programs that executed and replicated a given task, without much ability to adapt to new conditions in the surrounding environment. However, recent advances in AI and Machine Learning have made it possible to train computer algorithms with unprecedented effectiveness, which opened the door to having cyber-physical systems that can show intelligent behaviour and decision-making capabilities. Using simulated environments, one is now able to train such systems to exhibit decent performance in tasks whose complexity stumped state-of-the-art algorithms less than a decade ago. An approach that has proved extremely successful is Reinforcement Learning (RL). In this thesis, we used it (along with other AI techniques) to train a virtual flying drone to perform two different tasks. The first one consists in having the drone fly towards a predefined object, no matter where it is placed. The second one is to have it fly in a manner that would allow for the exploration of an unknown environment. We were able to combine both tasks: to find and head towards a specific target within an unknown environment, by using only the relative position of the drone to its taking off point and its camera, therefore without any environment specific information. After a process of trial and error, we developed a framework for exploration on a plane, excluding the movement on the yaw axis. In order to perform such tasks with a deep Q network model we had to retrieve a depth image, the relative position of the drone and a segmented image. The results presented herein demonstrate that a drone can be trained to be reasonably performant in the aforementioned tasks. It was achieved up to 81% accuracy on an unknown test environment for the first task while achieving 98% accuracy for the training environment on the same task. It holds the promise for doing the same with other cyber-physical systems and for more complex tasks.Under de senaste åren har obemannade flygplan och autonoma system i allmänhet blivit heta ämnen, både inom akademin och industrin. Faktum är att möjligheterna till tillämpning av sådan teknik är stora, med militär- och infrastrukturindustrin som de två mest framträdande fallen. Fram till nyligen medförde autonoma system föga flexibilitet då deras handlingar härrör från väldefinierade program som utför givna, väl specificerade uppgifter, utan större förmåga att anpassa sig till nya förhållanden i omgivningen. Nya framsteg inom AI och Machine Learning har däremot gjort det möjligt att träna datoralgoritmer med oöverträffad effektivitet, vilket öppnade dörren för att ha cyber-fysiska system som kan uppvisa intelligent beteenden och beslutsfattande förmågor. Med hjälp av simulerade miljöer kan man nu träna sådana system för att uppvisa acceptabel prestanda i uppgifter vars komplexitet förbryllade toppmoderna algoritmer för mindre än ett decennium sedan. Ett tillvägagångssätt som har visat sig vara mycket framgångsrikt är Reinforcement Learning (RL). I detta examensarbete använde vi denna metod (tillsammans med andra AI-tekniker) för att ”lära” en virtuell flygande drönare att utföra två olika uppgifter. Den första uppgiften bestod av att få drönaren att flyga mot ett fördefinierat objekt, oavsett var objektet är placerat. Den andra uppgiften innebar att få den att flyga på ett sätt som skulle möjliggöra utforskning av en okänd miljö. Vi kunde kombinera båda uppgifterna: att hitta och leda mot ett specifikt mål inom en okänd miljö, genom att bara använda drönarens relativa position i förhållande till dess startpunkt och dess kamera, därför utan någon miljöspecifik information. Efter en försöksprocess med ett flertal svårigheter utvecklade vi ett ramverk för prospektering på ett plan, med undantag av rörelsen på yaw-axeln. För att kunna utföra sådana uppgifter med en djup Q-nätverksmodell behövde vi hämta en djupbild, drönarens relativa position och en segmenterad bild. Resultaten som presenteras i denna rapport visar att en drönare kan utvecklas för att bli mer ”intelligent” avseende rimlig prestanda för att utföra de ovan nämnda uppgifterna. Vi uppnådde upp till 81% noggrannhet i en okänd testmiljö för en viss uppgift, samtidigt som vi uppnådde 98% noggrannhet för träningsmiljön på samma uppgift. Det ger hopp om att det i framtiden kommer vara möjligt att uppnå liknande fenomen med andra cyber-fysiska system och för mer komplexa uppgifter.
45
Naik, Sweta. "Design of control release drug delivery system (DDS) for imaging and therapeutic applications." VCU Scholars Compass, 2011. http://scholarscompass.vcu.edu/etd/2606.
Full textAbstract:
The main challenge in disease treatment is no more the discovery of new therapeutic drugs, but to provide targeted delivery of therapeutic drugs to specific sites without incurring systemic toxicity effects. An efficient way of reducing the toxicity is by encapsulating the drug with a biodegradable matrix that can provide controlled release of the drug along with local heating of the drug. Local heating can be obtained by incorporating magnetic iron oxide particles that heat upon exposure to AC electromagnetic fields. The magnetic iron oxide nanoparticles are also gaining much attention as MRI contrast agents. Thus it would be of potential benefit if a drug delivery system is designed to encapsulate the drug as well as the magnetic iron oxide nanoparticles within a biodegradable matrix, thereby providing a dual modal imaging and therapeutic delivery system. The key step in the design of a dual modal drug delivery system is the encapsulation of the magnetic iron oxide nanoparticles with polymer of choice. The magnetic iron oxide nanoparticles were encapsulated into a robust poly (styrene-co-vinylbenzylchloride-co-divinylbenzene) (PSVBDVB) to study these synthetic variations upon encapsulation with a polymer. The next step to the design of drug delivery system was to replace the PSVBDVB polymer by a biocompatible and biodegradable polymer- Poly (lactide-co-glycolide) (PLGA). The PLGA composites containing the Fe@FeOx core shell nanoparticles and the drug analog [Ru(bpy) dye] was prepared by oil-in water emulsion solvent evaporation technique. The local heating of the PLGA composites was also achieved by irradiating the Fe@FeOx nanoparticles with 2.45 GHz microwave radiations. Higher Ru(bpy) dye release from the composites by locally heating the sample with 2.45 GHz microwave pulse compared to externally heating the composite sample was achieved. The final step was the design of controlled release drug delivery system with dual modal imaging and therapeutic capabilities. To obtain narrow sized PLGA composites the Fe@FeOx nanoparticles were replaced by chloroform based ferrofluid. The ferrofluid was synthesized by novel thermolysis technique. The release of the dye from the PLGA composites when placed in the Rf induction coil was determined by fluorescence spectroscopy and a linear increase in the fluorescent intensity was observed with time. Also, the controlled release of the dye from the composites was achieved by a pulsed Rf treatment. Magnetic resonance imaging was also performed using the PLGA composites which showed enhancement in the T2-weighted image contrast and thus negligible reduction in the contrast capabilities of the iron oxide particles (R2 = 58.7 s-1mM-1). The PLGA composites containing the drug analog and the iron oxide nanoparticles thus constitute a controlled release drug delivery system with dual modal imaging and therapeutic capabilities.
46
Masilela, Mbonisi. "Supporting Data-Intensive Wireless Sensor Applications using Smart Data Fragmentation and Buffer Management." VCU Scholars Compass, 2007. http://scholarscompass.vcu.edu/etd/779.
Full textAbstract:
Recent advances in low power device technology have led to the development of smaller powerful sensors geared for use in Wireless Sensor Networks. Some of these sensors are capable of producing large data packets in a single reading. This becomes a challenging problem given the constraints imposed by current MAC and Transport Layer implementations since a single data packet can exceed the MTU of the protocol stack. Little has been done in the way of addressing this issue in Wireless Sensor Networks. This paper proposes a novel solution to this issue. Proposed is a Lightweight Data Transportation Protocol that uses smart data fragmentation and efficient pipelined transmission and buffer management schemes to solve this problem. The methodology outlined in this paper ensures that data is successfully transmitted from source to destination with minimal delay or packet loss.
47
Ramineni, Sri Ram. "Hidden History: A Mobile Application for Discovering Surrounding Landscapes." DigitalCommons@USU, 2016. https://digitalcommons.usu.edu/etd/4953.
Full textAbstract:
This thesis work describes the design, development and evaluation of a mobile application called Hidden History. This application lets users discover and explore three types of landscapes (Historic, Scenic and Cultural) using three different modes of discovery (Route, Explore and Tour).
Before designing Hidden History, the feature set of other applications that help users explore surrounding landscapes were identified and analyzed. Hidden History was then designed to implement the best features of these applications and offer several functionality improvements. Design began with iterative paper prototyping, following which a high fidelity, digital prototype was created. The high fidelity prototype was tested through two rounds of usability testing with target users. All the users found the application useful. User testing revealed many issues and areas of improvements for the application. By iteratively prototyping and testing the Hidden History application with users, researchers created a mobile application that better supports the discovery of landscape history. The thesis concludes with suggestions for future work to further improve the application.
48
Ordonez, Iván. "STA : Spatio-Temporal Aggregation of physical fields with applications to analysis of diffusion-reaction phenomena /." The Ohio State University, 1999. http://rave.ohiolink.edu/etdc/view?acc_num=osu1488192960171019.
Full text
49
Man, Gabriel Jen Shi. "Metal Oxide/Semiconductor Heterojunctions as Carrier-Selective Contacts for Photovoltaic Applications." Thesis, Princeton University, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10265452.
Full textAbstract:
Solar radiation is a vast, distributed, and renewable energy source which Humanity can utilize via the photovoltaic effect. The goal of photovoltaic technology is to minimize the true costs, while maximizing the power conversion efficiency and lifetime of the cell/module. Interface-related approaches to achieving this goal are explored here, for two technologically-important classes of light absorbers: crystalline-silicon (c-Si) and metal halide perovskite (MHP). The simplest solar cell consists of a light absorber, sandwiched between two metals with dissimilar work functions. Carrier-selective contacts (CSC’s), which are ubiquitous in modern solar cells, are added to improve the electrical performance. Solar cells require asymmetric carrier transport within the cell, which can be effected via electrostatic and/or effective fields, and CSC’s augment the asymmetry by selectively transporting holes to one contact, and electrons to the other contact.
The proper design and implementation of a CSC is crucial, as the performance, lifetime, and/or cost reduction of a solar cell can be hampered by a single interface or layer. A framework, consisting of eight core requirements, was developed from first-principles to evaluate the effectiveness of a given CSC. The framework includes some requirements which are well-recognized, such as the need for appropriate band offsets, and some requirements which are not well-recognized at the moment, such as the need for effective valence/conduction band density of states matching between the absorber and CSC.
The application of the framework to multiple silicon-based and MHP-based CSC’s revealed the difficulties of effectively designing and implementing a CSC. A poly(3-hexylthiophene)/c-Si heterojunction was found to be a near ideal hole-selective contact (HSC). Three metal oxide/c-Si heterojunctions initially expected to yield comparable electron-selective contacts (ESC’s), titanium dioxide/c-Si (TiO2/c-Si), zinc oxide/c-Si (ZnO/c-Si), and tin dioxide/c-Si (SnO2/c-Si), were instead discovered to be widely different. The TiO2/MHP heterojunction was found to be a moderately ideal ESC, and the nickel oxide/MHP (NiOX/MHP) heterojunction is expected to be a good HSC. If interfacial lead di-iodide (PbI2) is intentionally or unintentionally deposited at the interfaces of a MHP solar cell, it is expected to be detrimental to the operation of the NiOX/MHP HSC, but not to the TiO2/MHP ESC.
50
Tegfalk, Elin. "Application of machine learning techniques to perform base-calling in next-generation DNA sequencing." Thesis, KTH, Tillämpad fysik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-280487.
Full text