31 |
Clinical Trial Results with the MED-EL Fine Structure Processing Coding Strategy in Experienced Cochlear Implant UsersMüller, Joachim, Brill, Stefan, Hagen, Rudolf, Moeltner, Alexander, Brockmeier, Steffi-Johanna, Stark, Thomas, Helbig, Silke, Maurer, Jan, Zahnert, Thomas, Zierhofer, Clemens, Nopp, Peter, Anderson, Ilona 20 February 2014 (has links) (PDF)
Objectives: To assess the subjective and objective performance of the new fine structure processing strategy (FSP) compared to the previous generation coding strategies CIS+ and HDCIS. Methods: Forty-six adults with a minimum of 6 months of cochlear implant experience were included. CIS+, HDCIS and FSP were compared in speech perception tests in noise, pitch scaling and questionnaires. The randomized tests were performed acutely (interval 1) and again after 3 months of FSP experience (interval 3). The subjective evaluation included questionnaire 1 at intervals 1 and 3, and questionnaire 2 at interval 2, 1 month after interval 1. Results: Comparison between FSP and CIS+ showed that FSP performed at least as well as CIS+ in all speech perception tests, and outperformed CIS+ in vowel and monosyllabic word discrimination. Comparison between FSP and HDCIS showed that both performed equally well in all speech perception tests. Pitch scaling showed that FSP performed at least as well as HDCIS. With FSP, sound quality was at least as good and often better than with HDCIS. Conclusions: Results indicate that FSP performs better than CIS+ in vowel and monosyllabic word understanding. Subjective evaluation demonstrates strong user preferences for FSP when listening to speech and music. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
|
32 |
Prezentační věty v beletrii a odborném textu: aspekty syntakticko-sémantické, aktuálněčlenské a textové / Presentation sentences in fiction and academic prose: a syntactico-semantic, FSP and textual viewRohrauer, Leona January 2015 (has links)
The aim of the present thesis is to analyze syntactic realisations of the Presentation Scale (presentation sentences) as they are defined in the framework of Functional Sentence Perspective (FSP). Several aspects are examined: the semantic aspect is reflected in the observation of the semantic character of the presentation verb and in the semantic affinity it displays with its subject. From the syntactic viewpoint, the sentential architecture of presentation sentences is examined as well as the distribution of the syntactic realisations in text. The study also offers results as regards sentences implementing the Extended Presentation Scale, namely the syntactic realisation of the dynamic semantic function of Specification. The textual aspects concern the correlation between the type of presentation sentence, its location within a paragraph and its textual function. All the above-mentioned aspects are examined in sentences excerpted from texts of two different functional styles, viz. academic prose and fiction. The corpus on which the analysis is based comprises 1731 presentation sentences, 826 from texts of academic prose and 905 from texts of fiction. The theoretical part of the thesis aims both at presenting the FSP theory as it was developed by Jan Firbas and his followers and at a comprehensive...
|
33 |
Modificação microestrutural da liga de magnésio AZ31 por fricção e mistura a altas velocidades / Microstructure modification by high speed friction stir processing of magnesium AZ31 alloyValio, Gustavo Trindade 03 July 2015 (has links)
Submitted by Caroline Periotto (carol@ufscar.br) on 2016-09-26T15:05:24Z
No. of bitstreams: 1
DissGTV.pdf: 1872903 bytes, checksum: 8df6b2f211cfc4236fc723147c24d9bf (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-09-26T20:50:51Z (GMT) No. of bitstreams: 1
DissGTV.pdf: 1872903 bytes, checksum: 8df6b2f211cfc4236fc723147c24d9bf (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-09-26T20:50:56Z (GMT) No. of bitstreams: 1
DissGTV.pdf: 1872903 bytes, checksum: 8df6b2f211cfc4236fc723147c24d9bf (MD5) / Made available in DSpace on 2016-09-26T20:51:03Z (GMT). No. of bitstreams: 1
DissGTV.pdf: 1872903 bytes, checksum: 8df6b2f211cfc4236fc723147c24d9bf (MD5)
Previous issue date: 2015-07-03 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Due to the current growth in the fossil fuels consumption, there is a great concern about the increase in pollutant emissions. In order to reduce these emissions, research indicates that the decrease in vehicle weight can be one of the solutions to reduce these gas emissions. One possible way to reduce the car weight is the replacement of parts that uses high density metals by Magnesium alloys. The major problem with this replacement is the lack of ductility that this material has at room temperature, being necessary to heat the plates before the conformation. This heating process has a high production costs and it is unfeasible to use in the automotive industry today. In view of this problem, this work aims to study this lack of conformity to room temperature using a microstructure modification technique located in the regions of conformation. The technic used was Friction Stir Processing (FSP) at high speed. This processing is similar to Friction Stir Welding (FSW), but without joining materials. The FSP is just a localized microstructural modification. The analysis performed in this study after processing at 1, 7 and 10 m/min show that the microstructure and mechanical properties undergoes various changes at for every processing speed output different. The results showed that the material after processing improves the ductility at room temperature as grain size decreases. / Com o atual crescimento do consumo de combustíveis fosseis, existe uma grande preocupação com o aumento de emissões de gases poluente. Para redução dessas emissões, pesquisas apontam que a diminuição do peso de veículos pode ser uma das soluções para reduzir as emissões de gases poluentes pelo aumento da eficiência energética. Uma forma possível de diminuir o peso de automóveis é pela substituição de partes que utilizam metais com alta densidade por ligas de Magnésio. O grande problema desta substituição é a falta de dutilidade que este material possui a temperatura ambiente, sendo necessário aquecer as chapas antes da conformação. Atualmente este processo de aquecimento gera um alto custo de produção dificultando sua utilização na indústria automotiva. Tendo em vista este problema, o presente trabalho tem como objetivo entender esta dificuldade na conformação a temperatura ambiente e propor uma solução utilizando uma técnica de modificação microestrutural localizada nas regiões de conformação. Esta técnica é o Processamento por Fricção e Mistura (FSP – Friction Stir Processing) à altas velocidade. Este processamento é semelhante ao de Soldagem por Fricção e Mistura (FSW – Friction Stir Welding), mas sem a formação de uma região de união entre materiais. O FSP é apenas uma modificação microestrutural localizada. As análises realizadas neste estudo após o processamento à 1, 7 e 10m/min apontam que a microestrutura e as propriedades mecânicas sofrem variações diferentes a cada velocidade de processamento. Os resultados mostraram que o material obteve uma melhora na dutilidade à temperatura ambiente devido à diminuição do tamanho de grão.
|
34 |
Clinical Trial Results with the MED-EL Fine Structure Processing Coding Strategy in Experienced Cochlear Implant UsersMüller, Joachim, Brill, Stefan, Hagen, Rudolf, Moeltner, Alexander, Brockmeier, Steffi-Johanna, Stark, Thomas, Helbig, Silke, Maurer, Jan, Zahnert, Thomas, Zierhofer, Clemens, Nopp, Peter, Anderson, Ilona January 2012 (has links)
Objectives: To assess the subjective and objective performance of the new fine structure processing strategy (FSP) compared to the previous generation coding strategies CIS+ and HDCIS. Methods: Forty-six adults with a minimum of 6 months of cochlear implant experience were included. CIS+, HDCIS and FSP were compared in speech perception tests in noise, pitch scaling and questionnaires. The randomized tests were performed acutely (interval 1) and again after 3 months of FSP experience (interval 3). The subjective evaluation included questionnaire 1 at intervals 1 and 3, and questionnaire 2 at interval 2, 1 month after interval 1. Results: Comparison between FSP and CIS+ showed that FSP performed at least as well as CIS+ in all speech perception tests, and outperformed CIS+ in vowel and monosyllabic word discrimination. Comparison between FSP and HDCIS showed that both performed equally well in all speech perception tests. Pitch scaling showed that FSP performed at least as well as HDCIS. With FSP, sound quality was at least as good and often better than with HDCIS. Conclusions: Results indicate that FSP performs better than CIS+ in vowel and monosyllabic word understanding. Subjective evaluation demonstrates strong user preferences for FSP when listening to speech and music. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
|
35 |
Existenciální konstrukce there is/are a její české překladové ekvivalenty / Existential construction there is/are and its Czech translation counterpartsRumlová, Jana January 2021 (has links)
The Diploma thesis analyses the existential construction there is/are and its Czech translation equivalents. The existential construction is used to present a new phenomenon and is thus one of the basic forms of the presentation scale. Even though it is a commonly used construction in English, there is no direct equivalent in Czech. It was, therefore, assumed that the most common means of translating the existential sentences to Czech would be the verb být, the Czech equivalent of the verb be (as in There is a long way ahead of us. = Je před námi dlouhá cesta.), mít, the Czech equivalent of the verb have (as in There is a long way ahead of us = Máme před sebou dlouhou cestu) or other lexical verbs explicitly expressing existence of the given phenomenon, such as existovat (=exist), objevit se (=appear) and others. The theoretical part summarizes literature and previous work on the problematics of the presentation scale, presentation sentences and the construction there is/are. It also provides information about the functional sentence perspective, which is essential to the discussed topic. The final part of the theoretical section briefly discusses the previous work on the Czech translation equivalents of the existential construction. The aim of the empirical part was to gather 200 English...
|
36 |
Les difficultés des étudiants internationaux dans le système universitaire français : en quoi le Français sur Objectifs Universitaire (FOU) peut-il les aider à réussir leurs études ? / The difficulties of international students in the French university system : how can the French for university purpose help them to succeed in their studies?Corzo Zavaleta, Janet Ivonne 02 March 2018 (has links)
Ce travail s’inscrit dans le cadre de la didactique du Français sur Objectifs Universitaire. Il porte sur l’accueil des étudiants de nationalité étrangère en mobilité en France et les difficultés qu’ils rencontrent pour leur intégration dans le système universitaire français. L’objectif de ce travail est d’analyser les difficultés ressenties par d'étudiants en mobilité en France dans le cadre de leur parcours universitaire. Ces difficultés peuvent être liées aux dimensions linguistiques, culturelles et à l’organisation du système universitaire. Par ailleurs, ce travail cherche à donner des pistes et des alternatives pour améliorer l’intégration d'étudiants de nationalité étrangère en France ; donc nous avons essayé de proposer les bases pour l'élaboration d’un programme de Français sur Objectifs Universitaires (FOU) visant à préparer d'étudiants à l’acquisition de compétences langagières, disciplinaires et méthodologiques de la vie universitaire à partir de l’analyse de leurs besoins spécifiques. / This work is part of the pedagogy of “French as Foreign Language”, and more specifically French for university purpose. It focuses on the reception of foreign students who moved to France and are having difficulties relating to their integration into the French university system.The objective of this work was to analyze the difficulties felt by international students studying in France as part of their university career. The most difficulties were related to linguistic, cultural and organizational aspects of the university system..This work gives leads and alternatives to improve the integration of foreign students in French universities. There fore we propose basis for the development of a program for French university purpose aimed at preparing students to acquire linguistic, disciplinary and methodological skills for university life due to an analysis of their specific needs.
|
37 |
In-Situ Polymer Derived Nano Particle Metal Matrix Composites Developed by Friction Stir ProcessingKumar, Ajay January 2015 (has links) (PDF)
Ceramic metal matrix composites (CMMCs) are materials generally created by mixing of hard ceramic particles in a metal matrix. They were expected to combine the ductility and toughness of the metal with the high strength and elastic modulus of the ceramic. MMCs have potential applications in automotive, aeronautical and aerospace industries. Hence, a simple and economical method for fabricating MMCs is an area of intense research. In MMCs, damage evolution starts preferentially at particle matrix interface or at particle clusters in the matrix. This is due to the different physical and mechanical properties of the particle and matrix. Higher local particle volume content leads to higher stress triaxiality making it a preferential site for damage nucleation. Problems with lowering of ductility, fatigue, fracture and impact resistance, agglomeration of ceramic phase and issues related to the predictability of properties of MMCs have been the major issues that have limited their use. In order to overcome some of these shortcomings, the use of nano particles has been attracting increasing attention. The reason is their capability in improving the mechanical and physical properties of traditional MMCs. The dispersion of a nanoscale ceramic phase is needed in order to overcome the problems related to fatigue, fracture toughness, and creep behaviour at high temperatures. However, manufacturing costs, preparation of nano composites and environmental concerns have to be addressed.
Agglomeration of nano particles, when produced by the melt stir casting route, the primary route to produce MMCs, is a serious issue that limits the use of nano-particles to produce MMCs with good properties. To avoid agglomeration of the ceramic phase MMCs/nano MMCs have been produced through the powder metallurgy route. Agglomeration is avoided as this is a solid state process. Secondary processing, such as extrusion and rolling are often needed to fully consolidate materials produced in this manner. A high extrusion ratio is often required to get MMCs without porosity.
A new method of making nano-ceramic MMC using a polymer derived ceramics (PDC) has been reported. A polymer derived ceramic is a material that converts itself into a ceramic when heated above a particular temperature. In the PDC method a polymer precursor is dispersed in the metal and then converted in-situ to a ceramic phase. A feature of this process is that all the constituents of the ceramic phase are built into the organic molecules of the precursor (e.g., polysilazanes contain silicon, carbon, and nitrogen); therefore, a reaction between the polymer and the host metal or air is not required to produce the ceramic phase. The polymer can be introduced through casting or powder metallurgy route. In the casting route, the polymer powder is directly added to molten metal and pyrolyzed in-situ to create castings of metal-matrix composites. These composites have shown better properties at elevated temperatures but the problem of agglomeration of particles due to Van der Waal's forces and porosity still remains. In the powder method, the organic precursor was milled with copper powder and then plasma sprayed to produce a metal matrix composite. It is reported that these composites retains its mechanical strength close to the melting point of the copper. However, getting a nano sized distribution is difficult through this route as the plasma spray route is a melting and solidification method.
Solid state processing by powder metallurgy is possibly a better method to produce well dispersed nano-MMCs. However, powder metallurgy routes are much more expensive and only parts of limited sizes can be produced by this method.
Another solid state process Friction Stir Processing (FSP) has successfully evolved as an alternative technique to fabricating metal matrix composites. FSP is based on the principles of Friction Stir Welding (FSW). In FSW, a rotating tool with a pin and a shoulder is inserted into the material to be joined, and traversed along the line of the joint. The friction between the tool and the work piece result in localized heating that softens and plasticizes the material. During production of MMCs using FSP method, the material undergoes intense plastic deformation resulting in mixing of ceramic particles and the metal. FSP also results in significant grain refinement of the metal and has also been used to homogenize the microstructure. FSP technology has also been used to fabricate surface/bulk composites of Al-SiC, friction stir surfacing of cast aluminum silicon alloy with boron carbide and molybdenum disulphide powders and to produce ultra-fine grained Cu-SiC composites.
A major problem in the FSP of MMCs is severe tool wear that results from abrasion with hard ceramic particles. The progressive wear of the tool has been reported to increase the likelihood of void or defect development. This change in geometry has been reported in the friction stir welding of several MMCs. The problems concerning the tool life has become a serious issue in the application of FSP for producing MMCs.
In the present work the advantages of the PDC method and FSP have been combined to produce polymer derived nano ceramic MMCs. This method mainly consists of three steps. In the first step, a polymer, which pyrolysis to form a PDC at temperatures lower than the melting point of the metal, is dispersed in the metal by FSP. This step is different from the melt route where the PDC forms at temperatures above the melting point of the metal. In the second step, external pyrolysis of the polymer dispersed material is carried out. Since this is a solid state process at stresses much higher than the shear or fracture of the polymer is expected to get evenly and finely distribution in the metal. This is done by heating the polymer dispersed material to a temperature above the pyrolysation temperature of the ceramic but lower than the melting point of the metal matrix. It should be mentioned that some pyrolysis of the polymer is possible during the FSP process itself. In the third step FSP is carried out on the pyrolised material for removing porosity that would form due to gas evolution during pyrolysis and to get a more uniform dispersion of polymer derived ceramic particles in the matrix. This method will produce nano-scale metal matrix composites with a relatively high volume fraction of the ceramic phase. This method can be extended to big sheets or a particular region in a sheet with no or low wear of tools.
The material selected for the present study were pure Copper (99.9%) and Nickel Aluminum Bronze (NAB) copper alloy. The polymer precursor was poly (urea methyl vinyl) silazane, which is available commercially as CERASET. The polymer consists of silicon, carbon, nitrogen, oxygen and hydrogen atoms. The liquid precursor was thermally cross-linked into a rigid polymer, which was milled into a powder. This powder, having angular shaped particles of an average size of 10 µm, was used as the reinforcement. The polysilazanes convert into a highly refractory and amorphous ceramic upon pyrolysis and is known as polymer-derived silicon carbonitride which consists principally of silicon, carbon and nitrogen. The in-situ process is feasible because copper melts above the temperature at which the organic phase begins to pyrolise. The polysilazanes pyrolise in the temperature range of 973 to 1273 K, which lie below the melting temperature of copper, 1356K.The precursor has a density of approximately 1 gcm-3 in the organic phase and approximately 2 gcm-3 in the ceramic state. In the present work, we seek to introduce approximately 20 vol% of the ceramic phase into copper. The microstructure and mechanical properties of the developed copper-based in-situ polymer derived nano MMCs have been characterized in detail to understand the distribution of particles.
The microstructure of the as received, processed as well as the FSP composite material was characterized using Optical Microscope (OM), Scanning Electron Microscope (SEM), Electron Probe Micro Analyzer (EPMA) and Transmission Electron Microscope (TEM). OM and SEM microstructural observations show that PDC particles are distributed uniformly with a bimodal (submicron+micron) distribution. In addition, TEM micrographs reveal the formation of very fine PDC particles of diameter 10-30 nm. X-ray diffraction and Thermo-gravimetric analysis confirms the presence of ceramic phase (Si3N4/SiC) in the matrix.
Significant improvement in mechanical properties of the FSP PD-MMCs has been observed. This in-situ formed Cu/PDC composites show five times increase in micro-hardness (260Hv - 2.5GPa) compared to processed copper base metal and in-situ NAB/PDC composite shows two times increase in micro-hardness (325Hv- 3.2GPa) compared to NAB matrix. The Cu-PDC composites exhibited better tensile strength at room temperature. In-situ formed Cu-PDC composite’s yield strength increased from 110MPa to 235MPa as compared to processed base metal, where as ultimate tensile strength increases from 246MPa to 312MPa compared to processed base metal at room temperature. This strengthening could be attributed to the presence of in-situ formed hard phases and the concomitant changes in the microstructure of the matrix material such as reduction in grain size and contribution from Orowan strengthening.
In the present work, we have observed tool wear by observing tool after each FSP pass and apart from producing a significantly harder material with higher elastic modulus, possibly for the first time, the issue of tool wear has been overcome. This is due to the fact that the composite is made by the polymer route and that the ceramic fractures easily till it reaches the nano-size.
Wear studies of this composite was carried out in a pin-on-disc machine by sliding a pin made from the composite against an alumina disc. The wear rate of the FSP PD-MMC composites increased from 1.63×10-5 to 5.72×10-6 mm3/Nm. Improved wear resistance could be attributed to the presence of the in-situ formed hard nano-phase.
|
Page generated in 0.0308 seconds