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Dissertations / Theses on the topic 'Angle Classification'
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1
Prasert, Sunyaruk. "Multi angle imaging with spectral remote sensing for scene classification." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2005. http://library.nps.navy.mil/uhtbin/hyperion/05Mar%5FPrasert.pdf.
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Thesis (M.S. in Information Technology Management)--Naval Postgraduate School, March 2005.Thesis Advisor(s): Richard C. Olsen. Includes bibliographical references (p. 95-97). Also available online.
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Dungan, Kerry Edward. "Feature-based Vehicle Classification in Wide-angle Synthetic Aperture Radar." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1274402314.
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HIRIART, JEAN. "Existe-t-il une typologie cranio-faciale correspondant a la classification d'angle." Paris 5, 1990. http://www.theses.fr/1990PA05M143.
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Liu, Yunan. "Intermediary System Using Image Classification for Online Shopping." BYU ScholarsArchive, 2016. https://scholarsarchive.byu.edu/etd/6015.
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Online shopping is becoming a popular option for consumers. Currently, the most common product searching method that online shopping websites provide is keyword search. Most shoppers have to carefully select relevant keywords to search for their favorite products. Finding desired products using a query image for online shopping is currently not available. Image has been used for searching similar images in the database but they are usually not well annotated. Research effort has been devoted to developing reliable image-based retrieval systems for applications such as medical image retrieval and trademark search. None of these developments focuses on improving online shopping experiences for consumers. This thesis reports the development of an image retrieval system to provide better online shopping experience for consumers. The system searches products with similar appearance such as shape and textures to the query images the user provides. Turn angle is a contour based shape descriptor. It has many unique properties that make it a perfect shape matching method for image retrieval. The best matching image has the shortest shape distance to the query shape. Turn angle, however, could fail with slightly stretched shapes. Dynamic programming is used to help turn angle match slightly deformed shapes. Another technique called centroid distance is also included as a restriction for shape matching in order to avoid retrieving irrelevant or disparate shapes. With a well-built database, the enhanced turn angle descriptor that includes dynamic programming and centroid distance is able to reach a high accuracy rate.Shape matching alone is usually not sufficient for a powerful retrieval system. Products with similar shape but very different textures will not be distinguished based solely on shape matching. Edge histogram is a robust shape descriptor for texture matching. It can be implemented to construct either global or local histogram for this purpose. Global edge histogram uses only 5 bins, which is simple but ignores detail texture information. Local and semi-global edge histograms are more complex but retains detail texture information. A hierarchical matching system is built to combine the shape and texture descriptors for better retrieval accuracy.Easy access to the shopping system is desired. An Android Application is developed to provide consumers a convenient and friendly tool to use the system. Grab cut is applied to the captured image to segment the object from the background. The segmentation provides the retrieval system the required contour information for shape matching. The Android Application submits the captured image along with the segmented contour to the server. After the retrieval process is completed, the server sends retrieved images of similar products back to the Android App for the user to consider. Using the retrieval system via a handheld device provides a user-friendly online shopping experience.
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Forrest, J. I. M. "Classification of microalgal cells in flow cytometry : The potential of multiple angle light scatter measurements." Thesis, University of Strathclyde, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.371972.
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Drechsel, Dieter. "The evolution seen from the angle of quantum physics." Dieter Drechsel, 2021. https://slub.qucosa.de/id/qucosa%3A73998.
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In previous publications [1,7] the author described the base rivalry in monotonous DNA sequences and their effect on the DNA repair mechanism.
According to this theory, many base building blocks compete for the occupancy of the newly released base site in the replication of monotonous DNA sequences in the elongation phase. This gives them more and more kinetic energy from replication position to next position. Thus, there is a probability that a tautomeric base pair is formed behind the end of the monotonic sequence because of the tunneling effect.
After its replication a different, irreparable base pair develops from the tautomeric base pair, when the rivalry - energy leads to a very strong hydrogen bond. This happens, however, by chance. In the following, we will describe the 3 phenomena: The tunnel probability (section 2), the probability for coming up of a high – energy – base building block (Elitist, section 3),and the combination of both phenomena (section 4). The result of these calculations is the equation (28). It is remarkable that follows from these calculations that the length of the monotonous sequences, and also the length of DNA increases itself in the course of evolution (section 5). (Read up all detailed computations in [7].) [... from introduction]
7
Kramberger, Christian. "Angle resolved dielectric response in carbon nanotubes." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2008. http://nbn-resolving.de/urn:nbn:de:bsz:14-ds-1215697970004-33212.
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The thesis "Anlre resolved dielectric response in carbon nanotubes" is dedicated to expounding the the anisotropy in the fundamental dielectric response of carbon nanotubes. While nanotubes are along their axis essentially planar graphene, the rolled up topology gives rise to entirely new features for perpendicular polarizations.
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Nawathe, Piyush. "Neural Network Trees and Simulation Databases: New Approaches for Signalized Intersection Crash Classification and Prediction." Master's thesis, University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4067.
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Intersection related crashes form a significant proportion of the crashes occurring on roadways. Many organizations such as the Federal Highway Administration (FHWA) and American Association of State Highway and Transportation Officials (AASHTO) are considering intersection safety improvement as one of their top priority areas. This study contributes to the area of safety of signalized intersections by identifying the traffic and geometric characteristics that affect the different types of crashes. The first phase of this thesis was to classify the crashes occurring at signalized intersections into rear-end, angle, turn and sideswipe crash types based on the traffic and geometric properties of the intersections and the conditions at the time of the crashes. This was achieved by using an innovative approach developed in this thesis "Neural Network Trees". The first neural network model built in the Neural Network tree classified the crashes either into rear end and sideswipe or into angle and turn crashes. The next models further classified the crashes into their individual types. Two different neural network methods (MLP and PNN) were used in classification, and the neural network with a better performance was selected for each model. For these models, the significant variables were identified using the forward sequential selection method. Then a large simulation database was built that contained all possible combinations of intersections subjected to various crash conditions. The collision type of crashes was predicted for this simulation database and the output obtained was plotted along with the input variables to obtain a relationship between the input and output variables. For example, the analysis showed that the number of rear end and sideswipe crashes increase relative to the angle and turn crashes when there is an increase in the major and minor roadways' AADT and speed limits, surface conditions, total left turning lanes, channelized right turning lanes for the major roadway and the protected left turning lanes for the minor roadway, but decrease when the light conditions are dark. The next phase in this study was to predict the frequency of different types of crashes at signalized intersections by using the geometric and traffic characteristics of the intersections. A high accuracy in predicting the crash frequencies was obtained by using another innovative method where the intersections were first classified into two different types named the "safe" and "unsafe" intersections based on the total number of lanes at the intersections and then the frequency of crashes was predicted for each type of intersections separately. This method consisted of identifying the best neural network for each step of the analysis, selecting significant variables, using a different simulation database that contained all possible combinations of intersections and then plotting each input variable with the average output to obtain the pattern in which the frequency of crashes will vary based on the changes in the geometric and traffic characteristics of the intersections. The patterns indicated that an increase in the number of lanes of the major roadway, lanes of the minor roadway and the AADT on the major roadway leads to an increased crashes of all types, whereas an increase in protected left turning lanes on the major road increases the rear end and sideswipe crashes but decreases the angle, turning and overall crash frequencies. The analyses performed in this thesis were possible due to a diligent data collection effort. Traffic and geometric characteristics were obtained from multiple sources for 1562 signalized intersections in Brevard, Hillsborough, Miami-Dade, Seminole and Orange counties and the city of Orlando in Florida. The crash database for these intersections contained 27,044 crashes. This research sheds a light on the characteristics of different types of crashes. The method used in classifying crashes into their respective collision types provides a deeper insight on the characteristics of each type of crash and can be helpful in mitigating a particular type of crash at an intersection. The second analysis carried out has a three fold advantage. First, it identifies if an intersection can be considered safe for different crash types. Second, it accurately predicts the frequencies of total, rear end, angle, sideswipe and turn crashes. Lastly, it identifies the traffic and geometric characteristics of signalized intersections that affect each of these crash types. Thus the models developed in this thesis can be used to identify the specific problems at an intersection, and identify the factors that should be changed to improve its safetyM.S.C.E.
Department of Civil and Environmental Engineering
Engineering and Computer Science
Civil Engineering
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Feldkamp, Jan Moritz. "Scanning Small-Angle X-Ray Scattering Tomography." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2009. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-24925.
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The techniques of small-angle x-ray scattering (SAXS) and grazing-incidence small-angle x-ray scattering (GISAXS) have successfully been used for many years in the analysis of nanostructures in non-crystalline samples, e.g., polymers, metallic alloys, ceramics, and glasses. In many specimens, however, the nanostructure is not distributed homogeneously, but instead varies as a function of position in the sample. Conventional SAXS or GISAXS measurements on such heterogeneous samples merely yield an averaged scattering pattern of all the different structures present along the x-ray beam path. In this thesis, scanning tomography is combined with SAXS and GISAXS, revealing the individual local scattering cross section at each position on a virtual section through the sample. The technique thereby offers unique analytical possibilities in heterogeneous specimens. A brief review of the physics of x rays and x-ray scattering is given, before the methods of tomographic SAXS and GISAXS are introduced. Experimental requirements and limitations of both methods are discussed, including aspects of sampling, local rotational invariance and x-ray beam coherence. Experiments performed at the beamline BW4 at HASYLAB at DESY, Hamburg, Germany are described, illustrating the capabilities of the method. Finally, an outlook on possible future developments in tomographic small-angle x-ray scattering is givenDie Methoden der Röntgenkleinwinkelstreuung (SAXS) und Röntgenkleinwinkelstreuung unter streifendem Einfall (GISAXS) werden seit vielen Jahren erfolgreich eingesetzt zur Analyse von Nanostrukturen in nicht-kristallinen Proben, z.B. Polymeren, metallischen Legierungen, Keramiken und Gläsern. In vielen Proben ist die Nanostruktur allerdings nicht homogen verteilt, sondern variiert als Funktion des Ortes in der Probe. Konventionelle SAXS- oder GISAXS-Messungen an solch heterogenen Proben liefern lediglich ein über alle unterschiedlichen Strukturen entlang des Röntgenstrahls gemitteltes Streubild. In dieser Arbeit wird Rastertomographie mit SAXS und GISAXS kombiniert und so der lokale Streuquerschnitt an jedem Ort auf einem virtuellen Schnitt durch die Probe gewonnen. Diese Technik bietet so einzigartige Analysemöglichkeiten von heterogenen Proben. Es wird zunächst ein kurzer Überblick über die Physik der Röntgenstrahlung und Röntgenstreuung gegeben, bevor die Methoden der SAXS- und GISAXS-Tomographie eingeführt werden. Die experimentellen Anforderungen und Grenzen beider Methoden werden besprochen, wobei Aspekte der Abtastung, der lokalen Rotationsinvarianz und der Kohärenz im Röntgenstrahl eine Rolle spielen. Experimente, die an der Messstrecke BW4 am HASYLAB bei DESY, Hamburg, durchgeführt wurden, werden beschrieben, um die Möglichkeiten der Methode zu illustrieren. Schließlich wird ein Ausblick auf mögliche zukünftige Entwicklungen der Kleinwinkelstreutomographie gegeben
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Lam-Médioni, Régina. "Etude de l'angle goniaque sur des teleradiographies de 151 cas de faces longues en classe ii et iii d'angle." Paris 7, 1988. http://www.theses.fr/1988PA071052.
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Gruber, Wolfgang, Oleksiy Starykov, Wilhelm Oppermann, and Harald Schmidt. "Growth of amorphous domains in precursor derived Si-C-N-Ceramics studied with small angle X-ray scattering." Diffusion fundamentals 8 (2008) 9, S. 1-7, 2008. https://ul.qucosa.de/id/qucosa%3A14155.
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Amorphous precursor derived ceramics with the composition Si26C41N33 were isothermally annealed at 1500 °C for 5 minutes up to 190 minutes. Two series of measurements were carried out: one at a nitrogen partial pressure of 1 bar and one at a nitrogen partial pressure of 1 mbar. Small angle X-ray scattering was used to determine the diameter of the amorphous domains. The Guinier radius was found to vary from 9.5 Å to 13 Å irrespective of the partial pressure of nitrogen. This finding is quite surprising since crystallization of this material strongly depends on the partial pressure of nitrogen.
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Veith, Susanne R., France M. Berruex, Eric Hughes, and Sotiris E. Pratsinis. "Modelling aroma release from silica Sol-Gel particles using self-diffusion data obtained under magic angle spinning conditions." Diffusion fundamentals 3 (2005) 27, S. 1-2, 2005. https://ul.qucosa.de/id/qucosa%3A14318.
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Lindsey, David H. "Orthodontists' and Parents' Perspective of Occlusion in Varying Anterior-Posterior Positions: A Comparative Study." VCU Scholars Compass, 2017. http://scholarscompass.vcu.edu/etd/4758.
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Objective: The purpose was to compare orthodontists’ and parents’ perception of orthodontic treatment outcomes in the anterior-posterior (AP) dimension. Assessment of treatment time and compliance were also investigated.
Material and Methods: Parallel surveys for orthodontists (n=1000) and parents (n=750) displayed occlusions from 3 mm Class III (Cl III:3) to 3 mm Class II. Participants rated occlusal relationships on a 100 mm VAS from least to most acceptable (0-100).
Results: 233 orthodontists (23%) and 243 parents (32%) responded. Orthodontists (mean=93.9, 25.9) and parents (mean=80.7, 40.9) rated Class I (Cl I) occlusion most and Cl III:3 least acceptable. No significant difference was found between outcomes at 18 months versus 24 months. For all cases, parents were willing to extend treatment duration longer than orthodontists.
Conclusions: Orthodontists and parents viewed treatment outcomes in the AP dimension differently, rating Cl I as most acceptable. Parents were willing to extend treatment longer than orthodontists.
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Gravier, Pierre. "Orthodontie en technique linguale : traitement d'une malocclusion de classe ii division 1 d'angle avec extractions." Lyon 1, 1992. http://www.theses.fr/1992LYO1D064.
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Pampel, André. "Pulsed field gradient NMR in combination with magic angle spinning - new possibilities for studying diffusion in lipid membranes and heterogeneous materials." Diffusion fundamentals 2 (2005) 128, S. 1-2, 2005. https://ul.qucosa.de/id/qucosa%3A14470.
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Viel, Stéphane, Grégory Excoffier, Guilhem Pagès, Fabio Ziarelli, Corinne Delaurent, and Stefano Caldarelli. "Combined use of pulsed gradient spin echo and high resolution magic angle spinning to investigate solutes diffusion in presence of a chromatographic stationary phase." Diffusion fundamentals 6 (2007) 7, S. 1-2, 2007. https://ul.qucosa.de/id/qucosa%3A14179.
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Inosov, Dmytro. "Angle-Resolved Photoelectron Spectroscopy Studies of the Many-Body Effects in the Electronic Structure of High-Tc Cuprates." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2008. http://nbn-resolving.de/urn:nbn:de:bsz:14-ds-1213956641791-80565.
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In spite of the failures to find an ultimate theory of unconventional superconductivity, after many years of research the scientific community possesses a considerable store of theoretical knowledge about the problem. Over time, the focus is gradually shifted from finding a theoretical description of an experimentally observed phenomenon to distinguishing between multiple models that offer comparably reasonable descriptions. From the point of view of an experimentalist, this means that any qualitative under-standing of an experimental observation would no longer suffice. Instead, the empha-sis in the experimental research should be shifted to accurate quantification of obser-vations, which becomes possible only if the results available from all the available ex-perimental methods are connected together by the theoretical glue. Among the meth-ods that are to be unified, ARPES plays a central role. The reason for this is that it gives access to the single-particle excitation spectrum of the material as a function of both momentum and energy with very high resolution. Other experimental techniques, such as inelastic neutron scattering (INS), Raman spectroscopy, or the newly estab-lished Fourier-transform scanning tunneling spectroscopy (FT-STS) probe more com-plicated two-particle spectra of the electrons and up to now can not achieve the mo-mentum resolution comparable with that of ARPES. Such reasoning serves as the mo-tivation for the present work, in which some steps are done towards understanding the anomalous effects observed in the single-particle excitation spectra of cuprates and relating the ARPES technique to other experimental methods. First, the electronic properties of BSCCO are considered — the superconducting cuprate most studied by surface-sensitive methods. The recent progress in un-derstanding the electronic structure of this material is reported, focusing mainly on the many-body effects (renormalization) and their manifestation in the ARPES spectra. The main result of this part of the work is a model of the Green’s function that is later used for calculating the two-particle excitation spectrum. Then, the matrix element effects in the photoemission spectra of cuprates are discussed. After a general introduction to the problem, the thesis focuses on the recently discovered anomalous behavior of the ARPES spectra that partially originates from the momentum-dependent photoemission matrix element. The momentum- and excitation energy dependence of the anomalous high-energy dispersion, termed “waterfalls”, is covered in full detail. Understanding the role of the matrix element effects in this phenomenon proves crucial, as they obstruct the view of the underlying excitation spectrum that is of indisputable interest. Finally, the work describes the relation of ARPES with other experimental methods, with the special focus on the INS spectroscopy. For the optimally doped bilayer Bi-based cuprate, the renormalized two-particle correlation function in the superconducting state is calculated from ARPES data within an itinerant model based on the random phase approximation (RPA). The results are compared with the experimental INS data on BSCCO and YBCO. The calculation is based on numerical models for the normal and anomalous Green’s functions fitted to the experimental single-particle spectra. The renormalization is taken into account both in the single-particle Green’s function by means of the self-energy, and in the two-particle correlation function by RPA. Additionally, two other applications of the same approach are briefly sketched: the relation of ARPES to FT-STS, and the nesting properties of Fermi surfaces in two-dimensional charge density wave systems.
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Asif, Rameez. "Design and Implementation of System Components for Radio Frequency Based Asset Tracking Devices to Enhance Location Based Services. Study of angle of arrival techniques, effects of mutual coupling, design of an angle of arrival algorithm, design of a novel miniature reconfigurable antenna optimised for wireless communication systems." Thesis, University of Bradford, 2017. http://hdl.handle.net/10454/17143.
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The angle of arrival estimation of multiple sources plays a vital role in the field of array signal
processing as MIMO systems can be employed at both the transmitter and the receiver end
and the system capacity, reliability and throughput can be significantly increased by using array
signal processing. Almost all applications require accurate direction of arrival (DOA) estimation
to localize the sources of the signals. Another important parameter of localization systems is
the array geometry and sensor design which can be application specific and is used to
estimate the DOA.
In this work, various array geometries and arrival estimation algorithms are studied and then a
new scheme for multiple source estimation is proposed and evaluated based on the
performance of subspace and non-subspace decomposition methods. The proposed scheme
has shown to outperform the conventional Multiple Signal Classification (MUSIC) estimation
and Bartlett estimation techniques. The new scheme has a better performance advantage at
low and high signal to noise ratio values (SNRs).
The research work also studies different array geometries for both single and multiple incident
sources and proposes a geometry which is cost effective and efficient for 3, 4, and 5 antenna
array elements. This research also considers the shape of the ground plane and its effects on
the angle of arrival estimation and in addition it shows how the mutual couplings between the
elements effect the overall estimation and how this error can be minimised by using a decoupling
matrix.
At the end, a novel miniaturised multi element reconfigurable antenna to represent the receiver
base station is designed and tested. The antenna radiation patterns in the azimuth angle are
almost omni-directional with linear polarisation. The antenna geometry is uniplanar printed logspiral
with striplines feeding network and biased components to improve the impedance
bandwidth. The antenna provides the benefit of small size, and re-configurability and is very
well suited for the asset tracking applications.
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Schulz, Bertram. "Hochgenaue Lagezuordnung von Mikrobauteilen durch greiferintegrierte Winkelfeinstellung." Doctoral thesis, Zwickau : Verlag Wissenschaftliche Scripten, 2007. https://monarch.qucosa.de/id/qucosa%3A19055.
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Für die hochgenaue Lagezuordnung von Mikrobauteilen in Mikromontageprozessen
fehlen bislang Lösungen für eine greifernahe oder greiferintegrierte Winkelfeinstellung.
In der vorliegenden Arbeit werden Einflussfaktoren und Auswirkungen lokaler Restfehler
auf die Lagezuordnung im Mikromontageprozess diskutiert und Strategien für eine Lagekorrektur
am Mikrobauteil unmittelbar im Montageprozess abgeleitet. Im Mittelpunkt steht die Herleitung
und Erforschung eines kinematischen Grundprinzips für eine greiferintegrierte Winkelfein-
stellung. Eine durch Simulation des Verformungsverhaltens optimierte räumliche Biegegelenk-
struktur gestattet das spielfreie Einstellen und Halten kleinster Winkellagen im Winkel-
sekundenbereich um einen auf dem gegriffenen Bauteil liegenden Drehpunkt. Das Funktions-
prinzip dieses Übertragungsgliedes bildet die Grundlage für einen neuartigen modular
aufgebauten Präzisionsgreifertyp. Die Wirksamkeit der greiferintegrierten Winkelfein-
stellung wird an einem Anlagendemonstrator zur hochgenauen Bestückung optischer Leiter-
platten mit elektrisch-optischen Sende- und Empfangsmodulen nachgewiesen. Mithilfe des
neu entwickelten modularen Präzisionsgreifers lassen sich Mikromontagestrategien mit
prozessintegrierter bauteilindividueller Lagekorrektur umsetzen. Montagegenauigkeiten
unter 5 µm können damit besser anlagentechnisch beherrscht werden, ohne dass ein
zusätzliches manuelles Feinausrichten notwendig ist.For state-of-the-art micro assembly processes with high precision alignment of micro components, solutions for a precise angle adjustment near by or integrated into a gripper are not provided yet. In this PhD thesis influencing factors and implications of local alignment failures are will be discussed and correction strategies directly in the assembling flow are will be deduced. In the central point of the PhD thesis the derivation and investigation of a novel kinematic principle for a gripper integrated angle adjustment are located. A flexure hinge structure could be designed that enables a free from backlash adjusting and fixing of angles in a size of less angular seconds whereas the center of rotation is located on the gripped part. The hinge structure was optimized by simulating the deformation behavior. The functional principle of this mechanism presents the base of a novel type of a modular precision gripper. The effectivity of the gripper integrated angle adjustment was verified at the application of high precision mounting of electric-optical circuit boards with light coupling transmitter and receiver modules. With the help of the new developed precision gripper micro assembly strategies could be realized basing on in-process alignment corrections of the individual gripped micro part. Assembly accuracies below 5 microns could be achieved plantspecific in a better way without additional manual steps for fine positioning.
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Wajino, Mishamo, A. D. Dhathathreyan, and S. V. K. V. Kanth. "Comparative Studies on Effect of Cationic and Anionic Finishing Agents on Surface Property of Finished Leather - 243." Verein für Gerberei-Chemie und -Technik e. V, 2019. https://slub.qucosa.de/id/qucosa%3A34412.
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The present work attempts to analyze the surface and physical properties of leathers finished with cationic and anionic finishing chemicals. The contact angles of liquid drops resting on the leather surface have been used to evaluate surface energy, acidity, basicity components of the surface energy, polarity and work of adhesion. Contact angle values have been measured for chrome tanned and conventionally retanned crust and finished leather made by varying pigment and binder combinations. The wettability of finished leather has been correlated with the contact angle values: the higher the contact angle value the lesser is the wetting observed. Complete wetting can be obtained when the contact angle value is zero i.e. the drop of liquid spreads spontaneously on the surface and partial wetting is obtained when the contact angle value is in between 0and 900. Acrylic binders with different film forming properties, protein, polyurethane and butadiene binders have been combined to prepare different finish formulations.The results have been correlated with wet and dry rub fastness, finish adhesion, vamp flexing value, water vapour permeability and water proofness. It has been observed that when the surface of leather is coated with acrylic binder the contact angle value due to polar solvents(water) , non polar solvents(hexadecane) and moderately polar (DMSO) and methyl iodide show that as the thickness of coating increases, the contact angle value decreases for the base coat and sharply increases when top coat is applied. Top coats have the ability to increase the contact angle and they improve the performance properties of leather such as water resistance, fastness, finish adhesion etc. Cationic and anionic finishing formulations have been compared to study their effect in modifying the surface of finished leather based on contact angle values, wet and dry fastness to circular rubbing and water resistance. It has been observed that leathers finished using anionic finishing technique shows better wet rub fastness and water resistance effect compared to cationic finishing technique.
Take-Away:
The effect of number of top coats on water contact angle value were determined ,and the experiment showed that the value were decreased gradually at the beginning of the coat because the top coats are water based so during the coating process the hydrophobic nature of the surface of chrome tanned leather have decreased.
The experimental result from contact angle value showed that coating with pigments and binders have increased the contact angle value compared to the control crust.
It has been observed that leathers finished using anionic finishing technique shows better wet rub fastness and water resistance effect compared to cationic finishing technique.
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Yasothai, Arjunan, G. C. Jayakumar, S. Angayarkanny, N. K. Peter, and V. K. Swarna. "Nano-Bio Aldehyde system for Leather Manufacture - 227." Verein für Gerberei-Chemie und -Technik e. V, 2019. https://slub.qucosa.de/id/qucosa%3A34260.
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Development of eco-friendly chemicals from natural renewable resources are widely explored owing to its eco-acceptable and sustainability. Exploring biopolymers is the need of an hour to combat the
sustainability in leather processing. Finishing is an imperative step that enhances the aesthetic appeal of the final leathers, in which, protein finishing system is known for its glazing properties. Commonly used cross-linkers as such formaldehyde and glutaraldehyde are restricted owing to biocompatibility issues. However, the use of crosslinker is inevitable for protein finish system. In the present research, nano-bio polyaldehyde (NBP) system is established through selective oxidation of starch; the size of the system is fine-tuned in the nano range for effective and efficient crosslinking through emulsion technique. The architectural design of NBP is ascertained as a good crosslinking agent for leather finishing chemicals from the characterization studies. A particle size of the NBP system found to be in the range of 80-110 nm. The surface properties of NBP treated leathers were characterized by the contact angle. The leather samples showed improved hydrophobicity nature with a contact angle of ~ 126º and also enhanced wet, rub fastness, color fastness, and adhesion strength. The study provides an insight on tunability of known biopolymers for developing sustainable technology.
Take-Away:
An insight on tunability of known biopolymers for developing sustainable technology
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Seyller, Thomas, Sarah Roscher, Felix Timmermann, Marcus V. Daniel, Florian Speck, Martina Wanke, Manfred Albrecht, and Susanne Wolff. "Quasi-Freestanding Graphene on SiC(0001) by Ar-Mediated Intercalation of Antimony: A Route Toward Intercalation of High-Vapor-Pressure Elements." Wiley-VCH Verlag, 2019. https://monarch.qucosa.de/id/qucosa%3A35599.
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A novel strategy for the intercalation of antimony (Sb) under the (6√3 × 6√3)R30° reconstruction, also known as buffer layer, on SiC(0001) is reported. Using X-ray photoelectron spectroscopy, low-energy electron diffraction, and angle-resolved photoelectron spectroscopy, it is demonstrated that, while the intercalation of the volatile Sb is not possible by annealing the Sb-coated buffer layer in ultrahigh vacuum, it can be achieved by annealing the sample in an atmosphere of Ar, which suppresses Sb desorption. The intercalation leads to a decoupling of the buffer layer from the SiC(0001) surface and the formation of quasi-freestanding graphene. The intercalation process paves the way for future studies of the formation of quasi-freestanding graphene by intercalation of high-vapor-pressure elements, which are not accessible by previously known intercalation techniques, and thus provides new avenues for the manipulation of epitaxial graphene on SiC.
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Schrage, Christian. "Nanoskalige Halbleiter und funktionalisierte Kohlenstoffmaterialien: Darstellung, Charakterisierung und Anwendung in Elektrolumineszenzbauteilen." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-61572.
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In dieser Arbeit werden zwei Schwerpunkte behandelt. Zum Einen soll der Einsatz nanoskaliger Materialien als Funktionskomponenten in Elektrolumineszenzbauteilen beschrieben werden. Dabei wird in einem ersten Aufbau ein transparenter Nanokompositfilm als emittierende Schicht in einem, den organischen Leuchtdioden, analogen Aufbau eingesetzt, während in einer zweiten Struktur eine transparente Elektrode, die auf nanoskaligen Kohlenstoffmaterialien (Kohlenstoffnanoröhren bzw. Graphenen) basiert, hinsichtlich ihrer Eignung als Alternative zu etablierten transparenten Elektroden untersucht werden soll. In weiterführenden Arbeiten werden die Erfahrungen aus der Graphensynthese auf die Generierung poröser, funktionalisierter Kohlenstoffmaterialien angewendet. Verbindend, wird die Röntgenkleinwinkelstreuung eingesetzt, um in vergleichenden Untersuchungen möglichst detailierte Informationen über die jeweiligen Systeme zu erhalten.
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Friedrich, Sven. "Lineares Vibrationsschweißen von Kunststoffen im industriellen Umfeld." Doctoral thesis, Universitätsbibliothek Chemnitz, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-148986.
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Aufgrund der stetig wachsenden Anforderungen hinsichtlich Gewichtsreduzierung und Funktionsintegration, besonders im Bereich des Automobilbaus, werden traditionell aus metallischen Werkstoffen gefertigte Komponenten immer häufiger durch Kunststoffbauteile substituiert. Dem entgegen steht derzeit die Tatsache, dass, trotz hohen Prozessverständnisses und des Wissens um die Prozess-Struktur-Eigenschafts-Beziehungen beim Vibrationsschweißen, die theoretisch erzielbaren Schweißnahtfestigkeiten, von 90 % bis 100 % des unverstärkten Grundmaterials, in der industriellen Serienfertigung bei weitem nicht erreicht werden. Die Komplexität eines industriell gefertigten Bauteils wird an Plattenprüfkörpern simuliert. Die Ergebnisse der Schweißversuche zeigen, dass unterschiedliche Wandstärken im Schweißnahtbereich, Bauteilverzug und unterschiedliche Schwingrichungen innerhalb einer Schweißnaht zu ungleichmäßigen lokalen Prozessbedingungen währenden des linearen Vibrationsschweißprozesses führen. Diese hinterlassen lokale Schwachstellen, welche das Gesamtbauteilversagen bestimmen. Durch alternative Prozessführungsstrategien, wie das Hochdruckanfahren und die IR-Vorwärmung, können diese Schwachstellen reduziert und die Gesamtbauteilfestigkeit angehoben werden. Dies wird am Beispiel des Bauteilverzugs veranschaulichtDue to the increasing demands for weight reduction and integration of function, especially in the field of automotive, components made of metallic materials are increasingly being substituted by components made of thermoplastic materials. In contrast to this there is currently the fact that, despite the high process understanding of the vibration welding and the knowledge of the process-structure-property relationships, the theoretically achievable weld strengths of 90 % to 100 % of the unreinforced base material strength are far to be achieved in industrial series production. The complexity of an industrially manufactured component is simulated by using plate test specimens. The results of the welding experiments show that different wall thicknesses in the weld area, component warpage and different friction angle within the weld leads to nonuniform local process conditions during linear vibration welding process. This results in local weak spots, which reduce the total component strength. These local weak spots can be reduced by using alternative process strategies, such as in-process pressure variation and IR preheating. So not only the local strengths but also the total component strength will be increased. This is shown on the example of component warpage
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Henze, Kirstin. "Sally in New York: Leben in einer anglo-hispanoamerikanischen Welt." Universität Leipzig, 1998. https://ul.qucosa.de/id/qucosa%3A33258.
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Haerting, Mandy, Karen Radzey, Stefan Großmann, and Christian Müller. "Angie vs. Dr. Merkel." Universitätsbibliothek Chemnitz, 2008. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-200801069.
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Immer wieder fallen im Verlauf von Wahlkämpfen Schlagworte wie Personalisierung, Negativismus und Sensationalismus. Während diese Eigenschaften auf modern geführte Wahl-Kampagnen in den USA durchaus zutreffen mögen, so bescheinigen Studien deutscher Wahlforschungsinstitute für die Bundesrepublik doch recht durchwachsene Befunde. Im Zuge der Bundestagswahl 2005 haben wir uns mittels einer Inhaltsanalyse mit der Kandidatendarstellung Angela Merkels in der deutschen Qualitätspresse beschäftigt. Dabei ging es uns besonders um die Feststellung eines Wandels in der Darstellung Angela Merkels, welcher die Wähler in ihrer Wahlentscheidung beeinflusst haben könnte und um erkennbare Indizien für einen generellen Trend zur PersonalisierungDuring electoral campaigns one can always hear key words like personalization, negativism and sensationalism. While these terms may represent the harsh reality of modern campaigns in the US, the results for Germany are rather ambiguous, according to prominent scientific studies. Following the chronology of the German 2005 election of the Bundestag, we tried to evaluate the presentation of candidate Angela Merkel, who ran for chancellor’s office, in the German quality press. Our main goal was the verification of a change in the way the papers presented Angela Merkel, hence possibly influencing the electorate. Furthermore, we tried to find proof of a general trend of personalization in Germany’s elections of 2005
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Marzinzik, Sonja. "Early Anglo-Saxon belt buckles (late fifth to early eighth centuries A.D.) : their classification and context." Thesis, University of Oxford, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365469.
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Wieling, Sönke. "Besetzte und unbesetzte elektronische Struktur von geordneten Dünnschichtverbindungen der Seltenen Erden Eu und Yb mit den Übergangsmetallen Pd und Ni." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2003. http://nbn-resolving.de/urn:nbn:de:swb:14-1064490965781-71077.
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The present thesis deals with the occupied and unoccupied electronic states of intermetallic compounds of the rare-earth metals (RE) Eu and Yb with the transition metals Pd and Ni. The compounds were prepared in-situ as epitaxial thin films on single-crystalline substrates. For comparison, the experiments were extended to a Ba/Pd compound, which was prepared in the same way. All samples were characterised by low-energy electron diffraction (LEED), photoelectron spectroscopy (PES) and inverse photoemission (IPE). For the IPE experiments an appropriate spectrometer was built. It consists of a combination of a toroidal-grating and a crystal monochromator and enables experiments with photon energies in the range of 10-25 eV and at 1486.6 eV. LEED experiments reveal the formation of a AuCu3 structure with a (111) surface orientation for RE/Pd systems, while the formation of a CaCu5-structure with (0001) surface orientation for the Ba/Pd and Eu/Ni compounds was found. The Eu compounds show a surface-valence transition from the trivalent to the divalent configuration. An ordered overstructure is formed at the surface despite an increase of the ionic volume of Eu by about 40 %. The measured electronic structure is in good accordance with results of local-density-approximation band-structure calculationsIn der vorliegenden Dissertation werden die besetzten und unbesetzten elektronischen Zustände intermetallischer Verbindungen der Seltenen Erden (SE) Eu und Yb mit den Übergangsmetallen Pd und Ni betrachtet. Die Verbindungen wurden als epitaktische Dünnschichten in-situ auf einkristallinen Substraten präpariert und mittels niederenergetischer Elektronenbeugung (LEED), Photoelektronenspektroskopie (PES) und inverser Photoemission (IPE) charakterisiert. Zu Vergleichszwecken wurde die Untersuchung zusätzlich auf eine auf gleiche Weise präparierte Ba/Pd-Verbindung ausgedehnt. Für die Durchführung der IPE-Experimente wurde ein entsprechendes Spektrometer aufgebaut. Die Kombination aus einem Toroidgitter- und einem Kristallmonochromator ermöglicht wahlweise Experimente im Photonenenergiebereich von 10-25 eV und bei 1486,6 eV. Die Analysen der LEED-Daten ergaben für die SE/Pd-Systeme die Bildung der AuCu3-Struktur mit einer (111)-Oberflächenorientierung, für die Ba/Pd- und die Eu/Ni-Verbindungen die der CaCu5-Struktur mit (0001)"=Oberflächenorientierung. Die Eu-Verbindungen zeigen dabei Oberflächenvalenzübergänge von der drei- zu der zweiwertigen Konfiguration mit Ausbildung geordneter Überstrukturen an der Oberfläche trotz einer 40 prozentigen Zunahme des Eu-Ionenvolumens. Die beobachtete elektronische Struktur stimmt gut mit den Ergebnissen von Bandstrukturrechnungen in der lokalen Dichtenäherung überein
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Doan, Thi Thu Loan. "Investigation on jute fibres and their composites based on polypropylene and epoxy matrices." Doctoral thesis, Technische Universität Dresden, 2005. https://tud.qucosa.de/id/qucosa%3A24708.
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- Matrix modification of jute/polypropylene composites with MAHgPP - Fibre surface modification for epoxy/jute composites, including: NaOH treatment, silane coupling agents, epoxy dispersion and their combinations - Investigation the influence of modification on the performance of jute fibre and jute compostites.Untersuchungen zum mechanischen und thermischen Verhalten sowie zur Benetzung von Jutefasern im Ausgangszustand, nach Entwachsen und nach Oberflächenmodifikation, mit dem Ziel einer Verwendung als Verstärkungsfasern in Verbundwerkstoffen. Untersuchungen zum mechanischen und thermischen Verhalten sowie zur hygrothermischen Alterung von Jute/Polypropylen (PP) Verbunden. Einfluss des PP-Typs, der Modifizierung der Matrix mit Maleinsäureanhydrid gepfropftem PP und des Faservolumengehalts.Untersuchung der Grenzschicht in Jute/Epoxidharz Verbunden in Hinblick auf die mechanischen Eigenschaften nach Alkalibehandlung und Oberflächenmodifikation der Jutefasern. Jutefasern haben gute spezifische mechanische Eigenschaften. Die Einzelfasereigenschaften unterliegen der bei Naturfasern üblichen Streuung der mechanischen Eigenschaften. Im Gegensatz zu konventionellen Verstärkungsfasern (Glas, Carbon) nimmt wachstumsbedingt mit zunehmendem Faserquerschnitt die Festigkeit tendenziell zu. Faseroberflächenbehandlungen verbessern die Benetzbarkeit, erhöhen die thermische Stabilität und reduzieren die Feuchteaufnahme sowie den Diffusionskoeffizient. Jute/Polypropylen-Verbunde Chemische und physikalische Wechselwirkungen zwischen Faser und MAHgPP nach optimierter Kopplerauswahl verbessern in Abhängigkeit vom PP-Typ die Grenzflächenscherfestigkeit und die mechanischen Eigenschaften. Durch Einbeziehen der Grenzflächeneigenschaften können mit einer modifizierten Mischungsregel die Zugfestigkeiten der Verbunde beschrieben werden. Jute/Epoxidharz-Verbunde Faseroberflächenbehandlungen mit Natronlauge, Organosilanen, Epoxiddispersionen und deren Kombinationen führen zu verbesserter Benetzung, reduzierter Wasseraufnahme und verbesserter Haftung sowie verbesserten mechanischen Eigenschaften in Jute/Epoxidharz-Verbunden.
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Ahner, Nicole. "Wetting Optimized Solutions for Plasma Etch Residue Removal for Application in Interconnect Systems of Integrated Circuits: Benetzungsoptimierte Reinigungslösungen für die Entfernung von Plasmaätzresiduen für die Anwendung im Verdrahtungssystem integrierter Schaltungen." Doctoral thesis, Universitätsverlag der Technischen Universität Chemnitz, 2011. https://monarch.qucosa.de/id/qucosa%3A19826.
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In multi-level Co/low-k based interconnect systems of ultralarge-scale integrated electronic devices the removal of plasma etch residues by common plasma cleaning processes has been shown to alter material properties like k-value and leakage current of the low-k dielectric. Besides the development of less damaging plasma processes their substitution by wet cleaning steps is in the focus of research and development. With further decreasing feature dimensions the development of wet cleaning processes has to include wetting issues like the non-wetting of small features due to the surface energy of the liquid or pattern collapse effects of low-k dielectric trenches due to high capillary forces This work at first focuses on the determination of the surface energetic character of common cleaning solutions for PERR and differently etched or ashed low-k dielectric surfaces by contact angle analysis, to outline which combinations of solid and liquid will be critical regarding their wetting behavior. Besides the determination of the wetting behavior the contact angle analysis turned out to be a fast and sensible analytic tool to understand the surface modifications introduced by different plasma processes and can help to understand the mechanisms of plasma damage of low-k dielectric surfaces. The analysis showed that especially polymerizing plasma etch processes produce a low-energetic low-k dielectric surface with a negligible polar energy contributions, which inhibits their wetting by high energetic water based cleaning solutions, which actually are favored by semiconductor manufacturers. The strategy to overcome these wetting issues followed in the present work is the reduction of the surface energy of the cleaning liquids by the application of surfactants. Several types of surfactants have been applied to the cleaning liquids and the compatibility of the surfactant solutions to BEOL materials like low-k dielectrics, copper and diffusion barriers as well as their dynamic behavior has been studied. The analysis showed that choosing the appropriate rinsing solution after the cleaning process is essential to ensure its compatibility to porous low-k dielectrics. Optical, electrical and structural data indicated that DIW rinse in most of the cases was not able to remove residual surfactant species within the material, while for an IPA rinse most of the residual surfactants have been removed. Considering the data received for compatibility to low-k materials, copper and barriers, the dynamic behavior of the surfactant solutions as well as influences of increased bath temperature and long term stability a general advice about surfactant selection and processing of surfactant aided solutions within BEOL is given.In mehrlagigen Kupfer/low-k basierten Metallisierungssystemen hochintegrierter elektronischer Bauelemente kann die Entfernung von Residuen nach der Plasmastrukturierung des Dielektrikums mittels herkömmlicher Plasmareinigungsprozesse zur Schädigung der Isolatorschicht und damit zum Ansteigen der relativen Dielektrizitätszahl sowie der Leckströme führen. Neben der Entwicklung schädigungsarmer Plasmaprozesse stellt der Ersatz dieser Prozesse durch Nassreinigungsschritte zur Ätzresiduenentfernung eine vielversprechende Alternative dar. Mit stetig abnehmenden Strukturabmaßen ist bei der Entwicklung dieser Nassreinigungsprozesse neben der Materialkompatibilität auch das Benetzungsverhalten der Reinigungsflüssigkeit von entscheidender Bedeutung, da die Oberflächenenergie der Reinigungslösung das Eindringen dieser in kleinste Strukturen verhindern und es durch hohe Kapillarkräfte zum Kollaps von Grabenstrukturen im Dielektrikum kommen kann. In der vorliegenden Arbeit wurde zunächst mittels Kontaktwinkelanalyse die Oberflächenenergie verschieden prozessierter low-k Dielektrikaschichten sowie herkömmlicher Lösungen zur Entfernung von Ätzresiduen untersucht, um hinsichtlich ihres Benetzungsverhaltens besonders kritische Materialkombinationen aufzuzeigen. Neben der Bestimmung des Benetzungsverhaltens hat sich die Kontaktwinkelanalyse zur Oberflächenenergieberechnung als schnelle und empfindliche Methode zur Analyse der Auswirkung von Plasmaprozessen auf die Oberfläche von low-k Dielektrika erwiesen. Die Untersuchungen haben gezeigt, dass besonders polymerisierende Plasmaprozesse eine niederenergetische Oberfläche erzeugen, welche von den derzeit in der Halbleiterfertigung bevorzugten hochenergetischen wasserbasierten Reinigungslösungen nur schlecht benetzt wird. Um diesem Effekt entgegenzuwirken wurde in der vorliegenden Arbeit die Senkung der Oberflächenenergie der Reinigungslösungen durch Zugabe von Tensiden untersucht. Es wurden mehrere Tenside unterschiedlichen Typs den Reinigungsflüssigkeiten zugemischt und die Kompatibilität dieser Lösungen mit low-k Dielektrika, Kupferschichten und Diffusionsbarrieren untersucht sowie ihr dynamisches Verhalten analysiert. Dabei hat sich gezeigt, dass die Auswahl der geeigneten Spüllösung nach dem eigentlichen Reinigungsprozess von entscheidender Bedeutung ist. Optische, elektrische sowie strukturelle Daten deuten darauf hin, dass bei Verwendung einer Spülung mit deionisiertem Wasser in den meisten Fällen Tensidrückstände im porösen Dielektrikum verbleiben. Eine Spülung mit Isopropanol war hingegen in der Lage, einen Großteil dieser Tensidrückstände zu entfernen. Unter Einbeziehung der Daten zur Materialkompatibilität und dem dynamischen Verhalten der Tensidlösungen bei Raumtemperatur und erhöhter Badtemperatur sowie ihrer Langzeitstabilität konnte schließlich eine Prozessempfehlung für die Verwendung der benetzungsoptimierten Reinigungslösungen in der BEOL-Prozessierung gefunden werden.
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Rein, Susanne, Elisabet Hagert, Wolfgang Schneiders, Armin Fieguth, and Hans Zwipp. "Histological Analysis of the Structural Composition of Ankle Ligaments." Sage, 2015. https://tud.qucosa.de/id/qucosa%3A35487.
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Background: Various ankle ligaments have different structural composition. The aim of this study was to analyze the morphological structure of ankle ligaments to further understand their function in ankle stability. Methods: One hundred forty ligaments from 10 fresh-frozen cadaver ankle joints were dissected: the calcaneofibular, anterior, and posterior talofibular ligaments; the inferior extensor retinaculum, the talocalcaneal oblique ligament, the canalis tarsi ligament; the deltoid ligament; and the anterior tibiofibular ligament. Hematoxylin-eosin and Elastica van Gieson stains were used for determination of tissue morphology. Results: Three different morphological compositions were identified: dense, mixed, and interlaced compositions. Densely packed ligaments, characterized by parallel bundles of collagen, were primarily seen in the lateral region, the canalis tarsi, and the anterior tibiofibular ligaments. Ligaments with mixed tight and loose parallel bundles of collagenous connective tissue were mainly found in the inferior extensor retinaculum and talocalcaneal oblique ligament. Densely packed and fiberrich interlacing collagen was primarily seen in the areas of ligament insertion into bone of the deltoid ligament. Conclusions: Ligaments of the lateral region, the canalis tarsi, and the anterior tibiofibular ligaments have tightly packed, parallel collagen bundles and thus can resist high tensile forces. The mixed tight and loose, parallel oriented collagenous connective tissue of the inferior extensor retinaculum and the talocalcaneal oblique ligament support the dynamic positioning of the foot on the ground. The interlacing collagen bundles seen at the insertion of the deltoid ligament suggest that these insertion areas are susceptible to tension in a multitude of directions. Clinical Relevance: The morphology and mechanical properties of ankle ligaments may provide an understanding of their response to the loads to which they are subjected.
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Raddatz, M., and H. J. Schönfeldt. "Ejection and impact angles of saltating particles measured with a high-speed camera." Universität Leipzig, 2010. https://ul.qucosa.de/id/qucosa%3A16374.
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3D and 2D trajectory data of sand grains saltating over a bed are presented from highspeed camera measurements. They were obtained at Zingst peninsula and in laboratory using a wind tunnel. Trajectories, calculated with a Runge-Kutta procedure, using values of the mean wind profile and the air flow were fitted to the measured ones. The trajectory with the lowest RMSE against the measured one was used to estimate the
grain diameter of the saltating grain. Also ejection and impact angle, ejection and impact speed of the grain were determined. The results confirm earlier findings that ejection angles decreases with increasing grain diameter. Ejection angles between 57° and 27° for fine (63-200 μm) and middle (200-630 μm) ejecta and between 38° and
20° for coarse grains (630-2000 μm) were found. The impact angle β increases with increasing grain diameter. Impact angles between 8° and 15° for fine impactors and between 12° and 36° for middle and coarse grains were found. Additionally the ratio between the mean ejection angle α and mean impact angle β, which decrease with
increasing grain diameter (Rice et al., 1995), could be confirmed. The ration between the ejection speed ue and impact speed ui was found nearly the same for all determined grain sizes, but the grains ejected from the bed had an average speed of one order of magnitude less than the impact speed.
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Mandosio, Jean-Marc. "La classification des sciences et des arts a la renaissance : ange politien, l'omniscient (panepistemon, 1492) : edition, traduction et commentaire." Paris, EPHE, 1998. http://www.theses.fr/1998EPHE4045.
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Le panepistemon d'ange politien, lecon inaugurale d'un cours sur aristote (prononcee en 1490 et publiee en 1492), presente, en soixante-cinq courts paragraphes, tous les arts et toutes les disciplines. Bien que cet opuscule complexe et enigmatique soit considere comme fondamental par les historiens de la renaissance, il n'a jamais fait l'objet d'une etude d'ensemble qui en etablisse clairement lecontenu et la portee. On montre ici que politien, proche des idees de jean pic de la mirandole, fait preuve d'une << omniscience >> de type philologique : son propos est de repertorier, dans une perspective eclectique de conciliation des diverses doctrines philosophiques, les termes principaux des arts et des sciences de l'antiquite, meme si en realite il s'inspire parfois de sources medievales ou contemporaines. Le panepistemon constitue a la fois un point d'aboutissement de la reflexion des humanistes italiens du xve siecle sur l'encyclopedisme, et le prototype des grandes tentatives de synthese encyclopedique du xvie siecle. La comparaison de la classification de politien avec celles de ses predecesseurs (notamment leon battista alberti, auquel un long chapitre est ici consacre) et de ses contemporains (jerome savonarole, giorgio valla, gregor reisch), ainsi que la reconstitution de la fortune du panepistemon (a travers un certain nombre de reprises et de plagiats), permettent de situer cet ouvrage dans l'histoire de la culture europeenne des temps modernes. Ce texte fait ici l'objet, pour la premiere fois, d'une edition critique, d'une traduction et d'un commentaire detaille, avec indication des sources.
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Kaiser, André. "Modellierung maximaler menschlicher Muskelmomente auf Basis digitaler Menschmodelle – am Beispiel der oberen Extremitäten." Universitätsverlag der Technischen Universität Chemnitz, 2017. https://monarch.qucosa.de/id/qucosa%3A20881.
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Als Werkzeuge der virtuellen Ergonomie dienen arbeitswissenschaftliche digitale Menschmodelle zur ergonomischen Gestaltung von Produkten und Arbeitsplätzen. Hohen Weiterentwicklungsbedarf bestimmen ihre Anwender vor allem für die integrierten Kraftanalysen. Eine Möglichkeit zur gelenkwinkel- und kraftrichtungsabhängigen Berechnung statischer Aktionskräfte ohne komplexe Muskelmodellierung basiert auf Muskelmomenten, welche in Maximalmomentkörpern modelliert werden.
Die Arbeit schildert und diskutiert detailliert die Berechnung solcher Maximalmomentkörper am rechten Oberarm. Zwei separate Studien ermöglichen die Erstellung und Evaluierung. Im Rahmen der ersten Studie werden maximale Muskelmomente der Hauptbewegungen von Ellenbogen und Schulter in Abhängigkeit der Gelenkwinkelstellungen erfasst und in Polynomen interpoliert. Durch diese gelenkwinkelabhängigen Momente können die Maximalmomentkörper modelliert werden. Im Rahmen der zweiten Studie werden wirkenden Muskelmomente mit den prognostizierten verglichen. Die Ergebnisse zeigen, dass die Maximalmomentkörper die wirkenden Muskelmomente bei maximalen Kraftaufbringungen im Mittel auf etwa 2 % genau vorhersagen, wobei einen Streubereich von etwa 50 % zu beachten ist. Der Streubereich ist dabei durch eine kritische Diskussion erklärbar und unter anderem den psychophysischen Verfahren einer Maximalkraftmessung zurechenbar.Digital human models as tools of virtual ergonomics serve for the design of products and workplaces. High demands for further development determine their users, for the integrated force analyzes. One way to calculate joint-angle- and force-direction-dependent static forces without complex muscle modeling is based on muscle torques, which are modeled in maximum torque bodies known as “M-Potatos”. This work describes and discusses the calculation of such maximum torque bodies for the right upper arm. Two separate studies allow the preparation and evaluation. The first study explore the maximum muscle torques within the main movement directions of the elbow and shoulder and interpolate them as polynomials of the joint angle position. With these polynomials, the maximum torque bodies can be modeled. The second study compared effective muscle torques with those predicted. The results show that the maximum torque bodies predict the effective muscle moments at maximum isometric force application on average at about 2%, with a range of about 50% to be considered. The range can be explained by a critical discussion and, among other things, attributable to the psychophysical method of a maximum force measurement.
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Bounds, Jordan. "On the quasi-isometric rigidity of a class of right-angled Coxeter groups." Bowling Green State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1561561078356503.
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Langer, Enrico. "Der Einfluß von Kristallfehlern auf Kossel- und Weitwinkel-Interferenzen." Doctoral thesis, Technische Universität Dresden, 2004. https://tud.qucosa.de/id/qucosa%3A24550.
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Die Arbeit beschäftigt sich mit zerstörungsfreien Untersuchungen von Kristalldefekten an kompakten Proben mittels röntgenographischer Kossel- u. Weitwinkel-Mikrobeugung im Rasterelektronenmikroskop. Das REM wurde durch ein neu entwickeltes Aufnahmeverfahren so erweitert, daß die äußerst intensitätsschwachen Kossel-Röntgeninterferenzen mittels Phosphorszintillator und hochauflösendem, extrem empfindlichen CCD-Flächendetektor registriert werden können. Das aufwendige Röntgenfilmverfahren wurde damit abgelöst. Die Aufnahme-Techniken wurden so kombiniert, daß die sich gegenseitig ergänzenden Methoden, v.a. die Kossel- u. Pseudo-Kossel-, aber auch die Rückstreu-Elektronen-Beugung, erstmals mit einem einzigen CCD-System im REM ausführbar sind. Die Aufnahme von Kikuchi-Bändern wurde so weit verbessert, daß diese erstmalig bei vertikaler Inzidenz des Elektronenstrahls auf der Probe beobachtet werden konnten. Durch Einsatz einer fokussierenden Polykapillarlinse in einem Röntgenfluoreszenzspektrometer konnte die Anregung von Kossel-Linien durch Bremsstrahlung und erheblich kürzere Belichtungszeiten sowie deutlich höhere laterale Auflösungen erzielt werden. Für die komplementären Mikrobeugungsmethoden wurde ein einheitliches Programm entwickelt, dessen neue Art der Simulation komplizierter Weitwinkel-Kurven 4. Ordnung die Lokalisierung von Gitterbaufehlern im kompakten Kristall ermöglichte. Entsprechende Simulationen und Verfeinerungen der Kanüle erlaubten in feinkörnigen Polykristallen, wie Bariumtitanat, eine Einzelkornanalyse mit der Weitwinkel-Beugung. Insbesondere wurden markante Erhöhungen der Versetzungsdichte nahe der Korngrenze einzelner Kristallite in FeAl festgestellt. An intermetallischen Fe-Al-Verbindungen wurden in Weitwinkel-Kurven Feinstrukturen gefunden, die sich durch Umweganregungen in Zusammenhang mit Überstrukturen erklären lassen. An zugverformten Ni-Kristallen wurden Kossel- u. Weitwinkel-Linienbreiten in Abhängigkeit des Azimuts im symmetrischen Bragg-Fall ausgewertet u. mit theoretischen Modellen verglichen. Anisotrope Linienverbreiterungen durch die Wirkung von Stufenversetzungen konnten quantitativ nachgewiesen werden. Erste Kossel- u. Weitwinkel-Untersuchungen an zyklisch verformten Ni-Einkristallen zeigten, daß beobachtete perlenkettenförmige Intensitätsanhäufungen an Weitwinkelreflexen die Konfiguration von Versetzungswänden aus Stufenversetzungsdipolen im Kristallvolumen widerspiegeln. Erstmals konnte der Einfluß von Stapelfehlern auf Weitwinkel-Linien, der sich durch linsenförmige Intensitätsaufspaltungen zeigte, experimentell nachgewiesen, theoretisch erklärt und quantitativ bestimmt werden.The thesis deals with the nondestructive investigation of crystal defects by X-ray Kossel and Pseudo Kossel microdiffraction on compact specimens in the scanning electron microscope. The SEM was extended by means of a newly developed detection method in such a way that X-ray Kossel interferences, which are extremely faint in intensity, can be observed by a phosphor scintillator as well as a high resolution and ultra-sensitive CCD area detector. The demanding X-ray film method was thus replaced. The observation techniques were combined so that the mutually complementary methods, above all the Kossel and Pseudo Kossel, but also the electron backscattered diffraction, are made possible for the first time by using just one CCD system in the SEM. The detection of Kikuchi bands was improved to such a degree that these could be recorded even at vertical incidence of the electron beam on the specimen for the first time. It was shown that the lateral resolution of the Kossel technique under polychromatic X-ray tube excitation could be enhanced considerably and the exposure times strongly reduced by using a polycapillary lens in an X-ray fluorescence spectrometer. For the complementary microdiffraction methods a homogeneous simulation program was developed, whose novel way of simulating the complicated Pseudo Kossel curves of the fourth order enable the lattice defect localization in compact crystals. The corresponding simulations and refinements of the target tube allowed a single grain analysis also in fine-grained polycrystals like barium titanate with Pseudo Kossel X-ray diffraction. Particularly, a marked increase of the dislocation density was ascertained near the grain boundary of individual crystallites in FeAl. At intermetallic Fe-Al compounds Pseudo Kossel curves fine structures were found, which can be explained by umweg (detour) excitations in relation to superstructures. Kossel and Pseudo Kossel line widths were analyzed in dependence on the azimuth and compared with theoretical models at tensile deformed Ni-crystals in the symmetrical Bragg case. Anisotropic line broadenings through the effect of edge dislocations could be proved quantitatively. Conclusions could be drawn from the initial Kossel and Pseudo Kossel investigations of cyclically deformed nickel crystals with respect to the observed pearl-necklace-like intensity thickening at Pseudo Kossel lines reflecting the strong local variations of the dislocation density and, thus, the configuration of dislocation walls of edge dislocation dipoles inside the crystalline volume. For the first time, the effect of stacking faults on Pseudo Kossel reflections appearing by lens-shaped intensity splittings could be proved experimentally, explained theoretically and determined quantitatively.
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Kaka, Joolam. "The prevalence of occlusal traits in a selected Western Cape population." University of the Western Cape, 1993. http://hdl.handle.net/11394/8388.
Full textAbstract:
Magister Chirurgiae Dentium (MChD)state funded programmes are essential to provide a treatment for the dentally handicapped. To address this need a study was undertaken under the auspices of the Orthodontic Department of the University of the Western Cape to assess the orthodontic needs of children in the Western Cape. The purpose of this study was to determine the occlusal traits of Indian children in the Western Cape and to compare them with samples internationally. The sample consisted of 355 children, 12-14 years old, from schools administered by the House of Delegates. They were examined and recorded according to the methods set out by Baume et al. (1973), and Angle's Classification (1899) with the Dewey- Anderson (1919 and 1960) and EI-Mangoury and Mustafa (1991) modifications The results of this study showed that bilateral molar relationships were: normal in 72.9%; mesial in 5.8% and distal in 15.5% of the children examined. The remaining had an asymmetrical molar relationship (5.8%). The upper incisal area was found to be the most crowded area in the mouth followed by the lower incisal area. Anterior crowding was present in 58.2% and spacing in 12.7% of the sample. The mean overjet was 2.7mm and the mean overbite 2 .1mm. In the posterior segments, open bites accounted for approximately 6.5% and crossbites for 8.3% On the basis of Angle's Classification it was found that 17.1% had a normal occlusion and 54.9% an Angles Class I malocclusion, 16.9% an Angle's Class II malocclusion and 5.5% an Angle's Class III malocclusion. 5.6% of the candidates had an asymmetrical molar relationship. In comparison to other population groups the results suggest that the incidence of some occlusal traits of this Western Cape sample was similar to that of other population groups while some traits were more prevalent. The pattern of the distribution of Angles Classification was also similar to that reported in studies done elsewhere.
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Desenfans, Philip. "Aerodynamics of the Maple Seed." Aircraft Design and Systems Group (AERO), Department of Automotive and Aeronautical Engineering, Hamburg University of Applied Sciences, 2019. http://d-nb.info/1204982848.
Full textAbstract:
Purpose - The paper presents a theoretical framework that describes the aerodynamics of a falling maple (Acer pseudoplatanus) seed. --- Methodology - A semi-empirical method is developed that provides a ratio stating how much longer a seed falls in air compared to freefall. The generated lift is calculated by evaluating the integral of two-dimensional airfoil elements using a preliminary falling speed. This allows for the calculation of the definitive falling speed using Blade Element Momentum Theory (BEMT); hereafter, the fall duration in air and in freefall are obtained. Furthermore, the input-variables of the calculation of lift are transformed to require only the length and width of the maple seed. Lastly, the method is applied to two calculation examples as a means of validation. --- Findings - The two example calculations gave percentual errors of 5.5% and 3.7% for the falling speed when compared to measured values. The averaged result is that a maple seed falls 9.9 times longer in air when released from 20 m; however, this result is highly dependent on geometrical parameters which can be accounted for using the constructed method. --- Research limitations - Firstly, the coefficient of lift is unknown for the shape of a maple seed. Secondly, the approximated transient state is yet to be verified by measurement. --- Originality / Value - The added value of this report lies in the reduction of simplifications compared to BEMT approaches. In this way a large amount of accuracy is achieved due to the inclusion of many geometrical parameters, even though simplicity is maintained. This has been accomplished through constructing a simple three-step method that is fundamental and essentially non-iterative.
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Brooks, D. A. "The theory and methodology of classifications of the fifth and sixth centuries A. D. in Anglo-Saxon England with reference to great square-headed brooches." Thesis, University College London (University of London), 1994. http://discovery.ucl.ac.uk/1317752/.
Full textAbstract:
This thesis seeks to establish how to set up chronologically reliable classifications of fifth- and sixth-century metalwork, using square-headed brooches as the principal example. The problem arises from the absence in this period of the usual, more reliable, dating tools such as documents, coins and pottery. As a primary dating tool metalwork is therefore unsupported, and it is crucial that classification is carried out with great rigour and objectivity. The first half of this thesis (chapters 2 to 7) discusses various requirements which need to be met if classification is to be rigorous and objective. The overall conclusions are that: - existing classifications, not just of square-headed brooches but of all fifth- and sixth-century metalwork, may be unreliable; - reliance on existing chronologies, not just of square-headed brooches but of all fifth- and sixth-century metalwork, should be suspended for the time being; - the entire system should be re-assessed from first principles. The first stages of such a re-assessment are attempted in the second half of the thesis. Chapter 8 attributes much of the faulty existing methodology to a misunderstanding of the method devised and practised by Montelius in the late nineteenth century, compounded by a false analogy with biological evolution; and in chapter 9 a revised version of Montelius' actual method is proposed as a sound basis for re-assessing early Anglo-Saxon metalwork classifications. Chapters 10 to 12 then exemplify various attempts to classify a corpus of 95 complete great square-headed brooches by rigorous, objective methods. In chapter 13, however, it is shown that further progress is likely to be limited, for the time being, to applying the suggested methods to other artefact-types, thus producing groups of various artefacts all free-floating and awaiting evidence that will tie them down chronologically. Finally, in chapter 14 it is recommended that classifications of early Anglo-Saxon metalwork currently in use should be re-examined and if necessary revised; that (except for tentative dates for the beginning and end of Salin's Style I) the attaching of even suggested dates to artefacts of this period and their find contexts should be suspended; and that archaeologists should make an urgent search for objective methods of demonstrating contemporeanity of objects in addition to decorative similarity, especially toolmark links.
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Heinemann, André. "Modelle für die Kleinwinkel-Streuung und Anwendungen." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2001. http://nbn-resolving.de/urn:nbn:de:swb:14-1004968857625-22272.
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This work contributes to the structure investigation on the basis of small-angle neutron scattering (SANS). A new analytical scattering function for polydispers precipitates with diffusion zones is presented and used in SANS experiments. For diluted and dense packed systems structure describing parameter values were obtained. These results lead to a deeper understanding of the process of nanocristallization of amorphous alloys. The investigation of SANS on Fe73.5Si15.5B7Cu1Nb3 shows that the Fe3Si type nanocrystals created in the amorphous matrix during annealing are covered by Nb-atoms. The accumulation of Nb-atoms or Nb-B-aggregates acting as inhibitors at the surface of the nanocrystals is assumed to be the basic mechanism controlling the evolution of the precipitates. For the first time this inhibitor-model is shown to be correct without doubts. In the Zr32Ti7.5Al10Cu20Ni8 amorphous alloy the formation of ultrafine nanocystals of about 2-3 nm in diameter was observed. The nanocrystallization starts after ordered clusters achieved particular sizes and a certain packing fraction. This leads to a new model for the microscopic formation procedure of ultrafine nanocrystals in this amorphous alloy. Theoretical models of fractal systems are applied to complicated polydisperse materials. Both the theory for an exact surface fractal of Hermann (1994)and the model for coupled volume and surface fractals in the formulation of Wong (1992) are shown to be applicable. The latter approach is applied to experimental data here for the first time. With computer simulations conditions for scattering experiments were optained therewith predictions about the quality and grade of fractality in real specimens become possibleDie vorliegende Arbeit ist ein Beitrag zur Strukturaufklärung mittels Neutronen-Kleinwinkel-Streuung (SANS). Es wird eine neu entwickelte analytische Streufunktion für polydisperse Ausscheidungen mit Diffusionszonen genutzt, um SANS Experimente auszuwerten. Sowohl für verdünnte, als auch für dicht gepackte Systeme werden auf diese Weise quantitative Strukturparameter gewonnen. Diese liefern einen Beitrag zum Verständnis des Nanokristallisationsverhaltens amorpher metallischer Gläser. Die Auswertung der Experimente an on Fe73.5Si15.5B7Cu1Nb3 zeigt, dass Fe3Si-artige Nanokristalle, die während der Temperaturbehandlung in der amorphen Matrix entstehen, von Nb-Atomen bedeckt werden. Diese Ansammlung von Nb-Atomen oder von entsprechenden Nb-B-Aggregaten auf der Oberfläche dieser Ausscheidungen hemmt das Größenwachstum der entstehenden Nanokristalle. Dieses Inhibitor-Modell wurde hier erstmals zweifelsfrei bestätigt. In Proben des amorphen metallischen Glases Zr32Ti7.5Al10Cu20Ni8 werden ultrafeine Ausscheidungen mit Durchmessern von 2-3 nm beobachtet. Diese entstehen verzögert nach der Ausprägung dicht gepackter Gebiete mit erhöhter Nahordnungsstruktur. Es wird ein Modell vorgeschlagen, das diesen Prozess erklären kann. Theoretisch diskutierte Modelle für fraktale Systeme werden auf komplizierte polydisperse Materialien angewendet. Sowohl die Formulierung von Hermann (1994) für ein exaktes Oberflächenfraktal, als auch der erstmals auf experimentelle Daten angewendete Ansatz von Wong (1992) für ein gekoppeltes Volumen- und Oberflächenfraktal erweisen sich als praktisch nutzbar. Mittels Computersimulationen wurden Bedingungen abgeleitet, die an Streuexperimente zu stellen sind, damit Aussagen über Qualität und Grad von Fraktalität in realen Proben getroffen werden können
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Usov, Denys. "Switching of surface composition and morphology of binary polymer brushes." Doctoral thesis, Technische Universität Dresden, 2003. https://tud.qucosa.de/id/qucosa%3A24340.
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Switching of surface composition and morphology of binary polymer brushes in response to changes in solvent selectivity, heating above glass transition temperatures, and contact with a rubbery stamp was studied. The binary brushes: polystyrene/poly(2-vinyl pyridine) (PS/P2VP), poly(styrene-co-2,3,4,5,6-pentafluorostyrene)/poly(methyl (meth)acrylate) (PSF/P(M)MA), and PS/PMMA were synthesized via two-step surface-initiated radical polymerization. Wetting experiments show that switching of brushes? surface composition upon exposure to solvents of various thermodynamic quality occurs faster than in 6 s. It takes longer time (5-10 min), if rate of solvent diffusion into the brush film is low. Discontinuous switching of surface composition of binary brushes is found upon exposure to binary solvents with gradually changed selectivity. X-ray Photoelectron Spectroscopy (XPS) shows quantitatively that the top brush layer (1) is dominated by respective favourite polymers after exposure to solvents of opposite selectivity and (2) comprises both brush constituents in almost symmetric ratio after exposure to non-selective solvents. Morphologies of binary brushes obtained after exposure to the solvents were studied with Atomic Force Microscopy (AFM). Local top layer composition was sensed with X-ray Photoemission Electron Microscopy (XPEEM). The morphologies are relevant to the particular solvents, reproducible, and independent on previous solvents. Phase segregation beneath the brush top layers was visualized with plasma etching. Qualitative agreement of the experimentally observed morphologies and predicted with self-consistent field theory is found. Enrichment of a binary brush top layer with the polymer providing lower surface energy takes place after annealing. Perpendicular segregation of binary brush constituents was sensed with XPEEM on perpendicular walls of imprinted elevations after wet microcontact printing.
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Kozlowska, Magdalena. "Winkelaufgelöste XPS: Optimierung der mathematischen Modellierung und deren experimentelle Überprüfung." Doctoral thesis, Technische Universität Dresden, 2004. https://tud.qucosa.de/id/qucosa%3A24564.
Full textAbstract:
Heutzutage ist die Entwicklung neuer Technologien stark auf die Miniaturisierung und die Herstellung von Materialien im Nanometer-Bereich und deren Charakterisierung ausgerichtet. Besonders interessant sind Informationen über hergestellte "sandwich" Strukturen betreffs Art und Anzahl der Schichten, Dicke der Schichten und deren chemische Zusammensetzung. Die chemischen Informationen von den Proben sind sowohl nahe der Oberfläche als auch in tiefer liegenden Schichten (vergrabene Schichten) von Interesse. Da die üblichen Tiefenprofilverfahren durch das Auftreten von ionenstrahlinduzierten Probenschädigungen hier versagen, sind zerstörungsfreie Untersuchungen der Probenstruktur von Bedeutung. Winkelaufgelöste Röntgenphotoemissionsspektroskopie (ARXPS) ist eines der Verfahren, die ohne Beschädigung der Schichtstruktur der untersuchten Materialen Informationen über dünne Gebiete der Probe liefert. Die Charakterisierung der Probe basiert auf der Analyse der austretenden Photoelektronen unter verschiedenen Austrittswinkeln, weil damit die effektive Informationstiefe durch Analyse von Photoelektronenstrom aus verschiedenen Tiefen verändert wird. Die Untersuchungstiefe bei diesem Verfahren ist maximal ~10 nm. Aus dem ARXPS-Verfahren ist nur eine indirekte Information zu erhalten. Deshalb braucht man ein Werkzeug, mit dem die untersuchten Proben mit Hilfe von mathematischen Modellen quantitativ beschrieben werden können. In der vorliegenden Doktorarbeit wird gezeigt, dass die ARXPS-Modellrechnung unter bestimmten Voraussetzungen eine sinnvolle Methode zur Analyse von dünnen Barriere-, Oxid- und Segregationsschichtsystemen ist. Die Quantifizierung der ARXPS-Daten ist nur dann erfolgreich, wenn nicht nur der Einfluss der Abklinglänge der Photoelektronen berücksichtigt wird, sondern auch der Einfluss der mittleren Atomvolumina der Matrix in geeigneter Schichten und der korrigierten Empfindlichkeitsfaktoren berücksichtigt wird. Die Anpassung zwischen experimentellen und berechneten Daten verläuft unter Verwendung bestimmter Rand- und Grenzbedingungen durch Anwendung mathematischer Methoden gleichzeitig für alle betrachtete Winkel. Das Verhalten der ARXPS-Modellrechnung wurde unter verschiedenen Bedingungen überprüft. Zu diesem Zweck wurde eine theoretische Struktur simuliert, deren Verhalten (berechnete Schichtdicken, Bedeckungsgrad der Oberfläche mit der Kontamination, chemische Zusammensetzung der Schichten) untersucht wurde hinsichtlich der Einflüsse von verschiedener Dicken, von Rauhigkeiten an der Probeoberfläche, der Art der Kontamination an der Oberfläche die aus der ex situ Präparation resultiert, und der "Qualität" der betrachteten Information während der Quantifizierung (Peak-Fit Prozeduren). Zur Demonstration der Möglichkeiten der Modellrechnung wurden zwei Systeme untersucht. Das erste Schichtsystem Co/Al2O3/Al enthält eine dünne vergrabene Aluminiumoxid-Barriere, die durch Plasma-Oxidation mit Electron Cyclotron Resonance (ECR) bei unterschiedlichen Oxidationszeiten hergestellt wurde. Die Modellierung der Proben mit der ARXPS-Modellrechnung ergibt unterschiedliche Dicken von Al2O3, die mit der Zeit der Oxidation korrelieren. Je größer die Oxidationszeit ist, desto dickere Aluminiumoxidschichten bilden sich. Die Untersuchung der Alterungsprozesse an den ECR-Proben ergibt, dass die Dicke der Aluminiumoxide nicht beeinflusst wurde. Das bestätigt, dass die Co-Schicht erfolgreich Al2O3 vor weiterer Oxidation schützt. Das zweite Beispiel betrifft eine S/Fe Struktur, die während der Wärmebehandlung durch Schwefel-Segregation auf einer Fe(100)-Oberfläche entstanden ist. Mit Hilfe der ARXPS-Modellrechnung kann der Bedeckungsgrad mit dem Schwefel der Fe- Oberfläche berechnet werden. Um die Ergebnisse der Modellierung zu verifizieren, wurden die ausgewählten Strukturen mit anderen Methoden (z.B.: TEM, EELS, XRR) untersucht.
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Reiche, geb Höde Nora. "Frühe postoperative Vollbelastung nach Sprunggelenksfraktur." Doctoral thesis, Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-189639.
Full textAbstract:
Frühe postoperative Vollbelastung nach Sprunggelenksfrakturen
Höde N, Ahrberg A, Josten C
Fragestellung:
Laut Leitlinien der DGU soll es nach einer operativ versorgten Sprunggelenksfraktur zur Frühmobilisation kommen. In Literatur und Lehrbüchern wird jedoch häufig eine p.o. Ruhigstellung im Gips oder Cast bis zu 6 Wochen empfohlen.
Bei den eigenen Patienten erfolgt nach Versorgung einer Malleolarfraktur (AO 44 B oder C) ab dem 1. p.o. Tag eine schmerzorientierte Vollbelastung mit AirCast®-Schiene. Kommt es unter dieser frühen Vollbelastung zu einer erhöhten Komplikationsrate wie Materialversagen? Oder überwiegen die Vorteile durch das Vermeiden immobilisationsbedingter Komplikationen wie Thrombosen?
Methodik
Im Rahmen einer retrospektiven Studie wurden 82 Patienten (w:m = 47:35, 20-84 Jahre, Median 51 Jahre) eingeschlossen. Der Nachuntersuchungszeitraum betrug 5 - 68 Monate (Median 34,5 Monate). Nach der AO-Klassifikation lagen 46 (56,1%) B1-Frakturen, 15 (18,3%) B2-Frakturen, 12 (14,6%) B3-Frakturen und 9 (11%) C-Frakturen vor. Ausschlusskriterien waren Einschränkungen der aktiven Mobilisation durch Vorerkrankungen oder weitere Verletzungen sowie die Versorgung mit einer Stellschraube. Die Patienten wurden klinisch anhand des AOFAS-Scores nachuntersucht, es erfolgte eine radiologische Kontrolle und die Erfassung peri- und postoperativer Komplikationen wie Thrombosen, Infekte, Materialversagen und verzögerte Frakturheilung/Pseudarthrosen.
Ergebnisse und Schlussfolgerung
Der durchschnittliche Punktwert für den AOFAS Score beträgt für alle Patienten 89,38 Punkte (35-100, Median 98) und für den Score nach Olerud und Molander 85,24 Punkte (15-100, Median 95). Insgesamt traten neun (10,98%) Komplikationen auf: vier (4,88%) oberflächliche Wundheilungsstörung, vier Wundinfektionen (4,88%), darunter zwei Schraubenlockerungen (2,44%) und eine Redislokation nach erneutem Distorsionstrauma (1,22%). Weiteres Materialversagen oder Thrombosen traten nicht auf.
Die frühe postoperative Vollbelastung führt nicht zu einer erhöhten Komplikationsrate, die beschriebenen Infekte sind mit der Vollbelastung zu assoziieren. Immobilisationsbedingte Komplikationen werden vermieden, der Patient kann schneller mobilisiert werden. Daher ist eine Ruhigstellung nach operativ versorgten Malleolarfrakturen nicht zu empfehlen.
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Viennet, Emmanuel, and Loïc Bouchardy. "Preliminary design and testing of a servo-hydraulic actuation system for an autonomous ankle exoskeleton." Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71229.
Full textAbstract:
The work presented in this paper aims at developing a hydraulic actuation system for an ankle exoskeleton that is able to deliver a peak power of 250 W, with a maximum torque of 90 N.m and maximum speed of 320 deg/s. After justifying the choice of a servo hydraulic actuator (SHA) over an electro hydrostatic actuator (EHA) for the targeted application, some test results of a first functional prototype are presented. The closed-loop unloaded displacement frequency response of the prototype shows a bandwidth ranging from 5 Hz to 8 Hz for displacement amplitudes between +/-5mm and +/- 20mm, thus demonstrating adequate dynamic performance for normal walking speed. Then, a detailed design is proposed as a combination of commercially available components (in particular a miniature servo valve and a membrane accumulator) and a custom aluminium manifold that incorporates the hydraulic cylinder. The actuator design achieves a total weight of 1.0 kg worn at the ankle.
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Fuhrland, Matthias. "Konzeption und Umsetzung neuer Technologien zur biaxialen Winkelmessung und elektrooptischen Pseudostreckenmessung." Doctoral thesis, München Beck, 2007. http://d-nb.info/988973138/04.
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Hartwich, Kathleen, Alejandro Lorente Gomez, Jaroslaw Pyrc, Radosław Gut, Stefan Rammelt, and René Grass. "Biomechanical Analysis of Stability of Posterior Antiglide Plating in Osteoporotic Pronation Abduction Ankle Fracture Model With Posterior Tibial Fragment." Sage, 2017. https://tud.qucosa.de/id/qucosa%3A35489.
Full textAbstract:
Background: We performed a biomechanical comparison of 2 methods for operative stabilization of pronation-abduction stage III ankle fractures; group 1: Anterior-posterior lag screws fixing the posterior tibial fragment and lateral fibula plating (LSLFP) versus group 2: locked plate fixation of the posterior tibial fragment and posterior antiglide plate fixation of the fibula (LPFP). Methods: Seven pairs of fresh-frozen osteoligamentous lower leg specimens (2 male, and 5 female donors) were used for the biomechanical testing. Bone mineral density (BMD) of each specimen was assessed by means of dual-energy x-ray absorptiometry. After open transection of the deltoid ligament, an osteotomy model of pronation abduction stage III ankle fracture was created. Specimens were systematically assigned to LSLFP (group 1, left ankles) or LPPFP (group 2, right ankles). After surgery, all specimens were evaluated via CT to verify reduction and fixation. Axial load was then applied onto each specimen using a servohydraulic testing machine starting from 0 N (Zwick/Roell, Ulm, Germany) at a speed of 10 N/s with the foot fixed in a 10 degrees pronation and 15 degrees dorsiflexion position. Construct stiffness, yield, and ultimate strength were measured and dislocation patterns were documented with a high-speed camera. The normal distribution of all data was analyzed using Shapiro-Wilk test. The group comparison was performed using paired Student t test. Statistical significance was assumed at a P value of .05. Results: All specimens had BMD values consistent with osteoporosis. BMD values did not differ between the left and right ankles of the same pair (P = .762). The mean BMD values between feet of men (0.603 g/cm²) and women (0.329 g/cm²) were statistically different (P = .005). The ultimate strength for LSLFP (group 1) with 1139 ± 669 N and LPPFP (group 2) with 2008 ± 943 N was statistically different (P = .036) as well as the yield in LSLFP (group 1) 812 ± 452 N and LPPFD (group 2) 1292 ± 625 N (P = .016). Construct stiffness trended to be higher in group 2 (179 ± 100 kNn) compared to group 1 (127 ± 73 kN/m) but this difference was not statistically significant (P = .120). BMD correlated with bone-construct failure. Conclusion: Fixation of the posterior tibial edge with a posterolateral locking plate resulted in higher biomechanical stability than anterior-posterior lag screw fixation in an osteoporotic pronation-abduction fracture model. Clinical Relevance: The clinical implication of this biomechanical study is that the posterior antiglide plating might be advantageous in patients with osteoporotic pronation abduction stage III ankle fracture.
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Gauci, Marc-Olivier. "Description et classification 3D des glènes arthrosiques pour une planification préopératoire 3D assistée par ordinateur : l'épaule digitale normale et arthrosique Patient-specific glenoid guides provide accuracy and reproducibility in total shoulder arthroplasty, in The Bone & Joint Journal 98-B(8), 2016 A modification to the Walch classification of the glenoid in primary glenohumeral osteoarthritis using three-dimensional imaging, in Journal of Shoulder and Elbow Surgery 25(10), October 2016 Automated three-dimensional measurement of glenoid version and inclination in arthritic shoulders, in the Journal of Bone & Joint Surgery 100(1), January 2018 Proper benefit of a three dimensional pre-operative planning software for glenoid component positioning in total shoulder arthroplasty, in International Orthopaedics 42, 2018 The reverse shoulder arthroplasty angle: a new measurement of glenoid inclination for reverse shoulder arthroplasty, in Journal of Shoulder and Elbow Surgery 28(7), July 2019." Thesis, Brest, 2019. http://www.theses.fr/2019BRES0091.
Full textAbstract:
La modélisation tridimensionnelle est devenue plus accessible et plus rapide en orthopédie et en particulier en chirurgie de l’épaule. L’analyse morphométrique qui en est issue est utilisée pour permettre une meilleure compréhension de l’omarthrose. L’objectif global de cette thèse était de valider l’application d’un logiciel de segmentation automatisée tridimensionnelle dans les étapes de prise en charge du patient. Huit études ont permis de valider les mesures automatiques calculées par le logiciel, d’améliorer la classification des omarthroses primaires puis de décrire la géométrie 3D normale et pathologique de l’épaule. Des seuils numériques précis ont pu être établis entre les différents types. Le logiciel a permis de développer et valider l’utilisation d’un angle (RSA-angle) permettant de mieux positionner l’implant glénoïdien dans les prothèses inversées d’épaule. L’utilisation des mobilités simulées en 3D démontrait l’intérêt du logiciel dans la compréhension des conflits osseux après prothèse et des faiblesses de design d’implant. Enfin, le positionnement de l’implant glénoïdien en peropératoire avec un guide patient-spécifique imprimé en 3D correspondait fidèlement à sa planification préopératoire, cependant, la planification à elle seule améliorait déjà considérablement ce positionnement. Ce travail de thèse a permis de valider les performances et l’utilisation d’un logiciel de segmentation tridimensionnel et de planification préopératoire. Son application se retrouve dans plusieurs étapes de la prise en charge d’un patient atteint d’omarthrose et devrait progressivement s’intégrer dans la pratique quotidienne des chirurgiensThree-dimensional modelling has become more accessible and faster in orthopedics and especially in shoulder surgery. The subsequent morphometric analysis is used to provide a better understanding of shoulder arthritis.The overall objective of this Thesis was to validate the use of a 3D-automated segmentation software in the various steps of patients management.Eight studies allowed validating the automatic measurements calculated by the software, improving the classification of primary shoulder arthritis and then describing the normal and pathological 3D geometry of the shoulder. Accurate numerical thresholds could be established between the different types. The software developed and validated the use of an angle (RSAangle) to better position the glenoid implant in reverse shoulder arthroplasty. The use of simulated range of motion in 3D demonstrated the software’s interest in understanding bone impingements after prosthesis and implant design weaknesses.Finally, the positioning of the glenoid implant intraoperatively with a patient specific guide printed in 3D corresponded faithfully to its preoperative planning. However, planning alone already greatly improved this positioning. This Thesis made it possible to validate the performance and use of a software of three-dimensional segmentation and pre-operative planning. Its application is found in several steps of the management of a patient with shoulder arthritis and should gradually be integrated into the daily practice of surgeons
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Danzenbächer, Steffen. "Untersuchung der elektronischen Struktur quasi-zweidimensionaler Einlagerungsverbindungen." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2001. http://nbn-resolving.de/urn:nbn:de:swb:14-1008071605796-72078.
Full textAbstract:
Thema der vorliegenden Arbeit ist die Untersuchung ausgewählter niederdimensionaler Schichtgittersysteme, wobei das Hauptinteresse in der Erforschung der elektronischen Struktur im Zusammenhang mit Interkalationsexperimenten liegt. Einkristalline Graphit-, TiSe2- und TaSe2-Proben wurden vor und nach der Interkalation mit winkelaufgelöster Photoemission, Fermi- und Isoenergieflächenmessungen und Elektronenbeugung (LEED) analysiert. Als Interkalationsmaterialien wurden U, Eu, Gd und Cs verwendet. Die experimentellen Daten wurden mit Ergebnissen von LDA-LCAO-Bandstrukturrechnungen und Simulationen im Rahmen eines Single-Impurity-Anderson-Modells verglichen. Neben dem Einfluß unterschiedlicher Valenzelektronen der interkalierten Atome auf den Einlagerungsprozeß werden Fragen zum Lokalisierungsverhalten von 4f- und 5f-Zuständen und zu den Veränderungen in der Dimensionalität der Verbindungen durch die Einlagerung diskutiert. Ein weiterer Schwerpunkt dieser Arbeit befaßt sich mit Untersuchungen zur temperaturabhängigen Ausbildung von Ladungsdichtewellen in 1T-TaSe2Subject of the present thesis are investigations of selected low-dimensional layered lattice systems, with the principal goal to study the electronic structure in relation to intercalation experiments. Single-crystalline graphite-, TiSe2 - and TaSe2- samples were analyzed by angle-resolved photoemission, Fermi- and isoenergy-surface measurements, and low energy electron diffraction experiments before and after intercalation. U, Eu, Gd, and Cs were used as materials for the intercalation process. The experimental results were compared with theoretical LDA-LCAO band-structure calculations and with simulations in the framework of a single-impurity Anderson model. In addition to the influence of different numbers of valence electrons from intercalated atoms, questions concerning the localization of 4f and 5f states and changes in the dimensionality of the compounds due to the intercalation process are discussed. Investigations of the temperature dependent formation of charge density waves in 1T-TaSe2 complete this work
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Simon, Peter. "Ein präventivmedizinisches Konzept zur Untersuchung der kardiovaskulären Gesundheit." Master's thesis, Dresden International University, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-230445.
Full textAbstract:
Kardiovaskuläre Erkrankungen spielen eine immer dominanter werdende Rolle als Ursachen von Morbidität und Mortalität. Endotheliale Dysfunktion, Arteriosklerose und ischämische Herzerkrankungen sind unangefochten die häufigsten Todesursachen in hochentwickelten Ländern. Die Krankheitslast kardiovaskulärer Erkrankungen wird durch die globale Zunahme von Risikofaktoren wie Übergewicht, metabolischem Syndrom und Diabetes mellitus Typ 2 in Zukunft wohl weiter steigen. Keines der in der heutigen Form existierenden Gesundheitssysteme ist den gesundheitlichen Folgen dieser bedenklichen epidemiologischen Entwicklung gewachsen, ohne dafür beträchtliche Einschnitte in Qualität oder Quantität hinnehmen zu müssen. Präventivmedizinische Strategien haben im Vergleich zur Akutmedizin bisher eine wesentlich geringere Aufmerksamkeit erfahren. Aufgrund der weiterhin steigenden Krankheitslast werden gerade präventivmedizinische Strategien immer wichtiger. Die Ermittlung der individuellen kardiovaskulären Gesundheit beinhalten neben einer Untersuchung wichtiger physiologsicher Kernsysteme, einen besonderen Fokus auf die Stärkung der gesundheitlichen Eigenverantwortung durch Vermittlung entsprechender medizinischer Zusammenhänge. Dies kann durch geeignete und prognostisch wertvolle Untersuchungsmethoden und laienverständliche Interpretationen der komplexen kardiovaskulären Zusammenhänge realisiert werden. Mithilfe eines besseren Verständnisses für die eigene kardiovaskuläre Gesundheit und gezielter konkreter Hilfestellungen von ärztlicher Seite, können grundlegende Strukturen für einen achtsameren Umgang mit der eigenen Gesundheit geschaffen werden. Alltägliche körperliche Aktivität, Körperzusammensetzung, Gefäßsteifigkeit und die maximale Leistungsfähigkeit bilden aktuellen Studien zufolge vier relativ einfach zu erhebend Hauptdeterminanten kardiovaskulärer Gesundheit mit großer prädiktiver Vorhersagekraft für kardiovaskulärer Ereignisse. Die Einordnung der Untersuchungsbefunde unter Berücksichtigung altersentsprechender Referenzdaten bietet zusätzlich die Möglichkeit, chronologisches und biologisches Alter zu differenzieren. Darüber hinaus könnte das hier vorgestellte Untersuchungskonzept ebenso dafür eingesetzt werden, die Effektivität von zuvor eingeleiteten therapeutischen Strategien zu überprüfen und eine Übermedikation zu vermeiden. Ein stärkerer Fokus auf nachhaltige kardiovaskuläre präventivmedizinische Strategien birgt das Potential Morbidität und Mortalität zu Reduzieren und die Lebensqualität und Selbstbestimmung der Klienten zu steigernNowadays endothelial dysfunction, arteriosclerosis and ischaemic heart disease depict major issues in most developed countries. Chronic diseases cause an increasing number of deaths worldwide. Responsible for approximately 30% of all deaths, this number is shocking despite the knowledge that these lives could be saved in a realistic point of view. However, disturbing global tendencies and the increase in epidemic overweight, obesity, glucose intolerance and diabetes mellitus type 2 seem to amplify cardiovascular diseases and deaths. No existing medical care system could ever sufficiently match these emergent burdens of global chronic diseases if these tendencies will continue to grow. Due to fatal epidemiological changes general practitioners will not only have to treat more diseases of elderly people, but also be the first contact person for enquiries about their health concerning the cardiovascular systems of younger and older generations. Strengthening prevention concerning cardiovascular diseases is probably the most efficient and only way to escape the vicious circle of pathophysiological processes. To implement cardiovascular prevention it is essential to focus on cardiovascular health rather than on cardiovascular disease. In order to master this challenge sufficiently a deliberate concept of preventive examinations for cardiovascular health is required to quantify cardiovascular wellness and sharpen the awareness of one’s health. Therefore, it is to establish precise, predictive and cost-efficient examination methods to quantify cardiovascular health and subclinical changes at early stages of a disease. Broader acceptance of the preventive potential and the use of modern technological advances could therefore be a powerful instrument to solve the growing global problem of chronic diseases. In this context the routine evaluation of daily physical activity, body composition, arterial stiffness and the maximum physical performance could be a starting point for a preventive diagnostic approach. They can serve as future parameters reflecting health, detecting subclinical diseases and encouraging people’s responsibility for their own health. Detailed information about the major cardiovascular parameters opens specific and efficient course of action to create multiple strategies for gaining or rehabilitating cardiovascular wellbeing
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Boszczyk, Andrzej, Sławomir Kwapisz, Martin Krümmel, Rene Grass, and Stefan Rammelt. "Correlation of Incisura Anatomy With Syndesmotic Malreduction." Sage, 2018. https://tud.qucosa.de/id/qucosa%3A35490.
Full textAbstract:
Background: The anatomy of the syndesmosis is variable, yet little is known on the correlation between differences in anatomy and syndesmosis reduction results. The aim of this study was to analyze the correlation between syndesmotic anatomy and the modes of syndesmotic malreduction. Methods: Bilateral postreduction ankle computed tomography (CT) scans of 72 patients treated for fractures with syndesmotic disruption were analyzed. Incisura depth, fibular engagement into the incisura, and incisura rotation were correlated with degree of syndesmotic malreduction in coronal and sagittal planes as well as rotational malreduction. Results: Clinically relevant malreduction in the coronal plane, sagittal plane, and rotation affected 8.3%, 27.8%, and 19.4% of syndesmoses, respectively. The syndesmoses with a deep incisura and the fibula not engaged into the tibial incisura were at risk of overcompression, anteverted incisuras at risk of anterior fibular translation, and retroverted incisuras at risk of posterior fibular translation. Conclusions: Certain morphologic configurations of the tibial incisura increased the risk of specific syndesmotic malreduction patterns. Level of Evidence: Level III, comparative study.