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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
471

Entwurfsmethoden und Leistungsgrenzen elektromechanischer Schallquellen für Ultraschallanwendungen in Gasen im Frequenzbereich um 100 kHz / Design and Power Limits of Electro-mechanical Sound Sources for Air-borne Ultrasonic Transducers in the Frequency Range around 100 kHz

Leschka, Stephan 21 November 2005 (has links) (PDF)
Air-borne ultrasonic transducers are optimised to achieve a maximal sound pressure in a frequency range around 100 kHz. Moreover, the radiation of a high acoustic power is desired, which requires a large transducer area. Within this dissertation the ultrasonic transducers are, therefore, optimised to operate in the resonance mode. Using this operating point the maximal force is fed into the transducer while it is charged with the lowest loss possible. Many applications of air-borne ultrasound need a sufficient bandwidth in addition to a high sound pressure, that s why the swinging mass of the transducer has to be minimised. For these reasons, air-borne capacitive and piezoelectric film transducers take centre stage of these examinations. New network models of the stripe membrane and the pre-stressed stripe plate are derived to optimise these ultrasonic transducers. Besides its mechanical tension and its bending stiffness, the new network model of the pre-stressed and pressure loaded stripe plate takes also the stiffness caused by the shape of the plate into account. The examined transducers achive a maximal piston velocity around 1 m/s. / Ultraschallwandler für Anwendungen in Luft werden zur Bereitstellung eines maximalen Schalldrucks im Frequenzbereich um 100 kHz optimiert. Sie sollen außerdem die Abstrahlung einer großen Schallleistung zulassen, was eine große Wandlerfläche voraussetzt. Deshalb werden in dieser Arbeit die Ultraschallsender für den Resonanzbetrieb optimiert, wo man die maximale Krafteinspeisung bei minimalen Verlusten einstellt. Viele Anwendungen von Ultraschall in Luft benötigen neben einem hohen Schalldruckpegel auch eine ausreichende Bandbreite, wozu die schwingende Masse der Wandler zu minimieren ist. Deshalb stehen kapazitive und piezoelektrische Folienwandler im Resonanzbetrieb im Vordergrund der Untersuchungen. Zur Optimierung dieser Ultraschallsender werden die Netzwerkmodelle der Streifenmembran und der gespannten Streifenplatte abgeleitet. Neben der mechanischen Spannung und der Biegesteifigkeit berücksichtigt das Netzwerkmodell der gespannten und statisch druckbelasteten Streifenplatte die Formversteifung. Die untersuchten Wandler erreichen eine maximale Kolbenschnelle um 1 m/s.
472

Fysiologiska tester som motivator? : en studie som visar förändring av fysisk kapacitet hos äldre som genomgått fysiologiska tester

Sandlund, Moa, Ryhed, Anna January 2013 (has links)
Syfte och frågeställningar. Syftet med studien var att hos äldre studera förändring av fysisk kapacitet, i början och i slutet av en tvåmånadersperiod utan ledarledd träning eller rådgivning. Frågeställningarna ser ut som följande: Ses någon förändring av olika kroppsmått och fysiologiska testresultat (kondition, styrka, rörlighet och balans) i början jämfört med i slutet av en åttaveckorsperiod utan ledarledd träning? Hur skiljer sig förändringen mellan för- och eftertester för personer som fått ledarledd träning och rådgivning jämfört med en grupp som inte fått det men genomfört samma fysiologiska tester under motsvarande tidsomfång? Metod. I Testgruppen fullföljde 18 personer (7 män och 11 kvinnor) med en medelålder på 71 (66-78) år. Motsvarande siffror för Träningsgruppen, deltagare i hälsoprojekt vårterminen 2013, var 37 (16 män och 21 kvinnor), 70 (64-84) år. För att kunna mäta och jämföra eventuella förändringar utförde deltagarna två standardiserade förtest innan projektets start och åtta veckor senare ett eftertest varpå det kunde noteras eventuella förändringar utan att deltagarna påverkats mellan testerna med varken fysisk aktivitet, rådgivning eller kosthållning. Dessa resultat kunde sedan jämföras med deltagarna som fått ledarledd träning och rådgivning mellan testerna. Resultat. Både Testgruppen och Träningsgruppen visade en signifikant, om än liten, minskning i midjemått, höftmått och bukhöjd mellan andra förtestet och eftertest, som dock var något mer utpräglad för Träningsgruppen. Styrketester såsom Axelpress, Ryggtest och Buk/höftböjtest påvisade signifikanta förbättringar för Testgruppen, men inte vid benstyrketestet Uppresningar från stol. Träningsgruppen visade signifikanta förbättringar, vanligtvis i liknande omfattning, i alla dessa tester för uthållighetsstyrka, förutom i Buk/höftböjtestet. Konditionstesterna med cykelergometer och pyramidtestet samt balans- och rörlighetstester förbättrades signifikant enbart för Träningsgruppen, men inte för Testgruppen. Procentuella förändringar för de båda grupperna presenteras i arbetet. Slutsats. Slutligen kan konstateras att vissa förbättringar i fysisk kapacitet kan ske genom enbart fysiologiska tester som följs upp efter en tvåmånadersperiod med förnyade mätningar för motiverade relativt friska äldre deltagare. Flera av testerna för styrka, 6-minuters-gångtest samt buk- och höftmått gav förbättrat resultat vid eftertestet jämfört med förtest hos Testgruppen. Testgruppen visade inga anmärkningsvärda förbättringar vid konditionstesterna. Möjligen kan det vara så att ledarledd träning krävs för att konditionsförbättringar ska ske, medan det måhända kan vara lättare att öka sin styrka på egen hand om regelbundna fysiologiska tester sker.
473

Διερεύνηση των τεχνικών παραμέτρων για την μεγιστοποίηση της ποιότητας των παρεχομένων υπηρεσιών στα συστήματα MIMO

Φραγκιαδάκης, Αλέξανδρος 01 February 2013 (has links)
Στην παρούσα διπλωματική εργασία μελετάμε τα πλεονεκτήματα που επιφέρει η χρήση πολλαπλών κεραιών στον πομπό και στον δέκτη, κατά την μετάδοση, με στόχο την βελτίωση των παρεχομένων υπηρεσιών στο χρήστη. Στο Κεφάλαιο 1, γίνεται μια ιστορική αναδρομή των ασύρματων επικοινωνιών καθώς των σύγχρονων ασύρματων τεχνολογιών και κεραιών που χρησιμοποιούνται. Στη συνέχεια γίνεται μια αναφορά στις έννοιες του διαφορισμού, του κέρδους διάταξης και της χωρικής πολυπλεξίας οι οποίες συνδέονται άρρηκτα με τα συστήματα MIMO. Στο Κεφάλαιο 2, αναφερόμαστε σε όλα εκείνα τα χαρακτηριστικά που περιγράφουν το ασύρματο κανάλι και εξάγουμε την γραμμική σχέση εισόδου-εξόδου του ασύρματου καναλιού. Στην συνέχεια γίνεται μια ανάλυση των στοχαστικών μοντέλων περιγραφής του ασύρματου διαύλου διαλείψεων και πιο συγκεκριμένα των μοντέλων Rayleigh και Rice. Στο Κεφάλαιο 3 εξετάζουμε την αξιοπιστία διαφόρων τύπων κεραιοσυστημάτων, ως προς τον ρυθμό των ρυθμό των λανθασμένων συμβόλων στον δέκτη. Πιο συγκεκριμένα εξετάζεται η τεχνική Maximal Ratio Combining για τα συστήματα SIMO καθώς και του σχήματος Alamouti για τα συστήματα ΜISO. Συνεχίζοντας στα MIMO συστήματα αναλύουμε τις μεθόδους ισοστάθμισης για την ανάκτηση των δεδομένων, και πιο συγκεκριμένα τις τεχνικές Zero Forcing, Minimum Mean Square Error,V-Blast και καθώς και την βέλτιστη τεχνική Maximum Likelihood. Στο τελευταίο μέρος της εργασίας αναλύουμε τα πλεονεκτήματα των MIMO συστημάτων, ως προς την χωρητικότητα που προσφέρουν, σε στοχαστικά κανάλια διαλείψεων.Στη συνέχεια, γίνεται αναφορά στην μέθοδο SVD και στην αναπαράσταση του MIMO καναλιού από έναν αριθμό ανεξάρτητων SISO διαύλων. Κλείνοντας αναφέρουμε την μέθοδο βέλτιστης κατανομής ισχύος στις κεραίες του πομπού Water-filling, και στην περαιτέρω αύξηση της χωρητικότητας του διαύλου που προσφέρει. / In this diploma thesis we are investigating the benefits of using Multiple Input and Multiple Output antennas in information transmission, with final goal to improve Quality of Service. The first Chapter, includes a historical background of the wireless communications but also is a reference to the modern wireless and antenna technologies. Moreover, we introduce the definition of new concepts, such as diversity and array gain and also spatial multiplexing, which are closely connected with MIMO technology. In the second chapter, we introduce the characteristics which they are describe the wireless channel, while simultaneously we mention the linear input-output relationship of the wireless channel. Additionally, we analyze the stochastic wireless channel models, namely the Rayleigh and the Rician fading models. In the third chapter, we investigate the reliability of different types of antenna topologies, regarding the pace of the invalid symbols in the transmitter. More specifically, we examine the Maximal Ratio Combining and Alamouti technique, for SIMO and MISO systems respectively. The next step is to analyze the equalization methods, which are used in MIMO antennas, and more specifically are, Zero Forcing, Minimum Mean Square Error and V-Blast receivers, but also the optimal Maximum Likelihood equalizer. In the last part of this Thesis, we investigate the benefits of MIMO systems regarding the Capacity, in random channels. Also, a reference to the SVD method has been made,which we use to analyze the MIMO channel, in a number of parallel SISO channels. Lastly, we use the water-filling method to allocate, with the optimal way, the given power in the transmit antennas, a fact that leads to even greater Capacity gain.
474

Équation de diffusion généralisée pour un modèle de croissance et de dispersion d'une population incluant des comportements individuels à la frontière des divers habitats / Generalized diffusion equation for a growth and dispersion model of a population including individual behaviors on the boundary of the different habitats

Thorel, Alexandre 24 May 2018 (has links)
Le but de ce travail est l'étude d'un problème de transmission en dynamique de population entre deux habitats juxtaposés. Dans chacun des habitats, on considère une équation aux dérivées partielles, modélisant la dispersion généralisée, formée par une combinaison linéaire du laplacien et du bilaplacien. On commence d'abord par étudier et résoudre la même équation avec diverses conditions aux limites posée dans un seul habitat. Cette étude est effectuée grâce à une formulation opérationnelle du problème: on réécrit cette EDP sous forme d'équation différentielle, posée dans un espace de Banach construit sur les espaces Lp avec 1 < p < +∞, où les coefficients sont des opérateurs linéaires non bornés. Grâce au calcul fonctionnel, à la théorie des semi-groupes analytiques et à la théorie de l'interpolation, on obtient des résultats optimaux d'existence, d'unicité et de régularité maximale de la solution classique si et seulement si les données sont dans certains espaces d'interpolation. / The aim of this work is the study of a transmission problem in population dynamics between two juxtaposed habitats. In each habitat, we consider a partial differential equation, modeling the generalized dispersion, made up of a linear combination of Laplacian and Bilaplacian operators. We begin by studying and solving the same equation with various boundary conditions in a single habitat. This study is carried out using an operational formulation of the problem: we rewrite this PDE as a differential equation, set in a Banach space built on the spaces Lp with 1 < p < +∞, where the coefficients are unbounded linear operators. Thanks to functional calculus, analytic semigroup theory and interpolation theory, we obtain optimal results of existence, uniqueness and maximum regularity of the classical solution if and only if the data are in some interpolation spaces.
475

For?a muscular respirat?ria, qualidade de vida e modula??o auton?mica da frequ?ncia card?aca na distrofia miot?nica

Ara?jo, Thaise Lucena 22 July 2009 (has links)
Made available in DSpace on 2014-12-17T15:16:06Z (GMT). No. of bitstreams: 1 ThaiseLA.pdf: 779453 bytes, checksum: fe87c118f2c753bc8ffd4a32cb6a1146 (MD5) Previous issue date: 2009-07-22 / Background: The myotonic dystrophy (MD) is a multisystem neuromuscular disease that can affect the respiratory muscles and heart function, and cause impairment in quality of life. Objectives: Investigate the changes in respiratory muscle strength, health-related quality of life (HRQoL) and autonomic modulation heart rate (HR) in patients with MD. Methods: Twenty-three patients performed assessment of pulmonary function, sniff nasal inspiratory pressure (SNIP), the maximal inspiratory (MIP) and expiratory (MEP) pressure, and of HRQoL (SF-36 questionnaire). Of these patients, 17 underwent assessment of heart rate variability (HRV) at rest, in the supine and seated positions. Results: The values of respiratory muscle strength were 64, 70 and 80% of predicted for MEP, MIP, and SNIP, respectively. Significant differences were found in the SF-36 domains of physical functioning (58.7 ? 31,4 vs. 84.5 ? 23, p<0.01) and physical problems (43.4 ? 35.2 vs. 81.2 ? 34, p<0.001) when patients were compared with the reference values. Single linear regression analysis demonstrated that MIP explains 29% of the variance in physical functioning, 18% of physical problems and 20% of vitality. The HRV showed that from supine position to seated, HF decreased (0.43 x 0.30), and LF (0.57 x 0.70) and the LF/HF ratio (1.28 x 2.22) increased (p< 0.05). Compared to healthy persons, LF was lower in both male patients (2.68 x 2.99) and women (2.31 x 2.79) (p< 0.05). LF / HF ratio and LF were higher in men (5.52 x 1.5 and 0.8 x 0.6, p <0.05) and AF in women (0.43 x 0.21) (p< 0.05). There was positive correlation between the time of diagnosis and LF / HF ratio (r = 0.7, p <0.01). Conclusions: The expiratory muscle strength was reduced. The HRQoL was more impaired on the physical aspects and partly influenced by changes in inspiratory muscle strength. The HRV showed that may be sympathetic dysfunction in autonomic modulation of HR, although with normal adjustment of autonomic modulation during the change of posture. The parasympathetic modulation is higher in female patients and sympathetic tends to increase in patients with longer diagnosis / Introdu??o: A distrofia miot?nica (DM) ? uma doen?a neuromuscular multissist?mica que pode afetar a musculatura respirat?ria e a fun??o card?aca, e ocasionar preju?zos na qualidade de vida. Objetivos: Investigar as altera??es na for?a muscular respirat?ria, qualidade de vida relacionada ? sa?de (QVRS), e modula??o auton?mica da freq??ncia card?aca (FC) em pacientes com DM. M?todos: Foram avaliados 23 pacientes quanto ? fun??o pulmonar, press?o inspirat?ria nasal sniff (SNIP), press?es respirat?rias m?ximas (PIm?x e PEm?x), e QVRS (question?rio SF-36). Destes, 17 realizaram avalia??o da variabilidade da frequ?ncia card?aca (VFC) em repouso, nas posturas supina e sentada. Resultados: Os valores da for?a muscular respirat?ria foram de 64, 70 e 80%predito para PEm?x, PIm?x, e SNIP, respectivamente. Foi encontrada diminui??o significativa nos dom?nios do SF-36 capacidade funcional (58.7 ? 31,4 vs. 84.5 ? 23, p<0.01) e disfun??o f?sica (43.4 ? 35.2 vs. 81.2 ? 34, p<0.001) comparado a valores de refer?ncia. A an?lise de regress?o linear mostrou que a PIm?x explica 29% da vari?ncia na capacidade funcional, 18% na disfun??o f?sica e 20% na vitalidade. A VFC mostrou que, da postura supina para a sentada, o espectro AF diminuiu (0.43 x 0.30) e o espectro BF (0.57 x 0.70) e a raz?o BF/AF (1.28 x 2.22) aumentaram, com p<0.05. Comparado a valores de refer?ncia, BF foi inferior (p<0.05) tanto nos pacientes homens (2.68 x 2.99), como nas mulheres (2.31 x 2.79). A raz?o BF/AF e o espectro BF foram maiores nos homens (5.52 x 1.5 e 0.8 x 0.6), e o espectro AF, nas mulheres (0.43 x 0.21), com p<0.05. Houve correla??o significativa positiva entre tempo de diagn?stico e raz?o BF/AF (r= 0.7, p< 0.01). Conclus?es: Indiv?duos com DM t?m for?a muscular expirat?ria diminu?da. A QVRS mostrou-se mais prejudicada em rela??o a aspectos f?sicos e parcialmente influenciada por varia??es na for?a muscular inspirat?ria. Pode haver disfun??o simp?tica na modula??o auton?mica da FC, com ajuste normal da postura supina para a sentada. A modula??o parassimp?tica ? superior em pacientes mulheres e a modula??o simp?tica tende a aumentar nos pacientes com maior tempo de diagn?stico
476

Conformal spectra, moduli spaces and the Friedlander-Nadirahvili invariants

Medvedev, Vladimir 08 1900 (has links)
Dans cette thèse, nous étudions le spectre conforme d'une surface fermée et le spectre de Steklov conforme d'une surface compacte à bord et leur application à la géométrie conforme et à la topologie. Soit (Σ, c) une surface fermée munie d'une classe conforme c. Alors la k-ième valeur propre conforme est définie comme Λ_k(Σ,c)=sup{λ_k(g) Aire(Σ,g)| g ∈ c), où λ_k(g) est la k-ième valeur propre de l'operateur de Laplace-Beltrami de la métrique g sur Σ. Notons que nous commeçons par λ_0(g) = 0. En prennant le supremum sur toutes les classes conformes C sur Σ on obtient l'invariant topologique suivant de Σ: Λ_k(Σ)=sup{Λ_k(Σ,c)| c ∈ C}. D'après l'article [65], les quantités Λ_k(Σ, c) et Λ_k(Σ) sont bien définies. Si une métrique g sur Σ satisfait λ_k(g) Aire(Σ, g) = Λ_k(Σ), alors on dit que g est maximale pour la fonctionnelle λ_k(g) Aire(Σ, g). Dans l'article [73], il a été montré que les métriques maximales pour λ_1(g) Aire(Σ, g) peuvent au pire avoir des singularités coniques. Dans cette thèse nous montrons que les métriques maximales pour les fonctionnelles λ_1(g) Aire(T^2, g) et λ_1(g) Aire(KL, g), où T^2 et KL dénotent le 2-tore et la bouteille de Klein, ne peuvent pas avoir de singularités coniques. Ce résultat découle d'un théorème de classification de classes conformes par des métriques induites d'une immersion minimale ramifiée dans une sphère ronde aussi montré dans cette thèse. Un autre invariant que nous étudions dans cette thèse est le k-ième invariant de Friedlander-Nadirashvili défini comme: I_k(Σ) = inf{Λ_k(Σ, c)| c ∈ C}. L'invariant I_1(Σ) a été introduit dans l'article [34]. Dans cette thèse nous montrons que pour toute surface orientable et pour toute surface non-orientable de genre impaire I_k(Σ)=I_k(S^2) et pour toute surface non-orientable de genre paire I_k(RP^2) ≥ I_k(Σ)>I_k(S^2). Ici S^2 et RP^2 dénotent la 2-sphère et le plan projectif. Nous conjecturons que I_k(Σ) sont des invariants des cobordismes des surfaces fermées. Le spectre de Steklov conforme est défini de manière similaire. Soit (Σ, c) une surface compacte à bord non vide ∂Σ, alors les k-ièmes valeurs propres de Steklov conformes sont définies comme: σ*_k(Σ, c)=sup{σ_k(g) Longueur(∂Σ, g)| g ∈ c}, où σ_k(g) est la k-ième valeur propre de Steklov de la métrique g sur Σ. Ici nous supposons que σ_0(g) = 0. De façon similaire au problème fermé, on peut définir les quantités suivantes: σ*_k(Σ)=sup{σ*_k(Σ, c)| c ∈ C} et I^σ_k(Σ)=inf{σ*_k(Σ, c)| c ∈ C}. Les résultats de l'article [16] impliquent que toutes ces quantités sont bien définies. Dans cette thèse on obtient une formule pour la limite de σ*_k(Σ, c_n) lorsque la suite des classes conformes c_n dégénère. Cette formule implique que pour toute surface à bord I^σ_k(Σ)= I^σ_k(D^2), où D^2 dénote le 2-disque. On remarque aussi que les quantités I^σ_k(Σ) sont des invariants des cobordismes de surfaces à bord. De plus, on obtient une borne supérieure pour la fonctionnelle σ^k(g) Longueur(∂Σ, g), où Σ est non-orientable, en terme de son genre et le nombre de composants de bord. / In this thesis, we study the conformal spectrum of a closed surface and the conformal Steklov spectrum of a compact surface with boundary and their application to conformal geometry and topology. Let (Σ,c) be a closed surface endowed with a conformal class c then the k-th conformal eigenvalue is defined as Λ_k(Σ,c)=sup{λ_k(g) Aire(Σ,g)| g ∈ c), where λ_k(g) is the k-th Laplace-Beltrami eigenvalue of the metric g on Σ. Note that we start with λ_0(g) = 0 Taking the supremum over all conformal classes C on Σ one gets the following topological invariant of Σ: Λ_k(Σ)=sup{Λ_k(Σ,c)| c ∈ C}. It follows from the paper [65] that the quantities Λ_k(Σ, c) and Λ_k(Σ) are well-defined. Suppose that for a metric g on Σ the following identity holds λ_k(g) Aire(Σ, g) = Λ_k(Σ). Then one says that the metric g is maximal for the functional λ_k(g) Aire(Σ, g). In the paper [73] it was shown that the maximal metrics for the functional λ_1(g) Aire(Σ, g) at worst can have conical singularities. In this thesis we show that the maximal metrics for the functionals λ_1(g) Aire(T^2, g) and λ_1(g) Aire(KL, g), where T^2 and KL stand for the 2-torus and the Klein bottle respectively, cannot have conical singularities. This result is a corollary of a conformal class classification theorem by metrics induced from a branched minimal immersion into a round sphere that we also prove in the thesis. Another invariant that we study in this thesis is the k-th Friedlander-Nadirashvili invariant defined as: I_k(Σ) = inf{Λ_k(Σ, c)| c ∈ C}. The invariant I_1(Σ) was introduced in the paper [34]. In this thesis we prove that for any orientable surface and any non-orientable surface of odd genus I_k(Σ)=I_k(S^2) and for any non-orientable surface of even genus I_k(RP^2) ≥ I_k(Σ)>I_k(S^2). Here S^2 and RP^2 denote the 2-sphere and the projective plane respectively. We also conjecture that I_k(Σ) are invariants of cobordisms of closed manifolds. The conformal Steklov spectrum is defined in a similar way. Let (Σ, c) be a compact surface with non-empty boundary ∂Σ then the k-th conformal Steklov eigenvalues is defined by the formula: σ*_k(Σ, c)=sup{σ_k(g) Longueur(∂Σ, g)| g ∈ c}, where σ_k(g) is the k-th Steklov eigenvalue of the metric g on Σ. Here we suppose that σ_0(g) = 0. Similarly to the closed problem one can define the following quantities: σ*_k(Σ)=sup{σ*_k(Σ, c)| c ∈ C} and I^σ_k(Σ)=inf{σ*_k(Σ, c)| c ∈ C}. The results of the paper [16] imply that all these quantities are well-defined. In this thesis we obtain a formula for the limit of the k-th conformal Steklov eigenvalue when the sequence of conformal classes degenerates. Using this formula we show that for any surface with boundary I^σ_k(Σ)= I^σ_k(D^2), where D^2 stands for the 2-disc. We also notice that I^σ_k(Σ) are invariants of cobordisms of surfaces with boundary. Moreover, we obtain an upper bound for the functional σ^k(g) Longueur(∂Σ, g), where Σ is non-orientable, in terms of its genus and the number of boundary components.
477

Entwurfsmethoden und Leistungsgrenzen elektromechanischer Schallquellen für Ultraschallanwendungen in Gasen im Frequenzbereich um 100 kHz

Leschka, Stephan 23 July 2004 (has links)
Air-borne ultrasonic transducers are optimised to achieve a maximal sound pressure in a frequency range around 100 kHz. Moreover, the radiation of a high acoustic power is desired, which requires a large transducer area. Within this dissertation the ultrasonic transducers are, therefore, optimised to operate in the resonance mode. Using this operating point the maximal force is fed into the transducer while it is charged with the lowest loss possible. Many applications of air-borne ultrasound need a sufficient bandwidth in addition to a high sound pressure, that s why the swinging mass of the transducer has to be minimised. For these reasons, air-borne capacitive and piezoelectric film transducers take centre stage of these examinations. New network models of the stripe membrane and the pre-stressed stripe plate are derived to optimise these ultrasonic transducers. Besides its mechanical tension and its bending stiffness, the new network model of the pre-stressed and pressure loaded stripe plate takes also the stiffness caused by the shape of the plate into account. The examined transducers achive a maximal piston velocity around 1 m/s. / Ultraschallwandler für Anwendungen in Luft werden zur Bereitstellung eines maximalen Schalldrucks im Frequenzbereich um 100 kHz optimiert. Sie sollen außerdem die Abstrahlung einer großen Schallleistung zulassen, was eine große Wandlerfläche voraussetzt. Deshalb werden in dieser Arbeit die Ultraschallsender für den Resonanzbetrieb optimiert, wo man die maximale Krafteinspeisung bei minimalen Verlusten einstellt. Viele Anwendungen von Ultraschall in Luft benötigen neben einem hohen Schalldruckpegel auch eine ausreichende Bandbreite, wozu die schwingende Masse der Wandler zu minimieren ist. Deshalb stehen kapazitive und piezoelektrische Folienwandler im Resonanzbetrieb im Vordergrund der Untersuchungen. Zur Optimierung dieser Ultraschallsender werden die Netzwerkmodelle der Streifenmembran und der gespannten Streifenplatte abgeleitet. Neben der mechanischen Spannung und der Biegesteifigkeit berücksichtigt das Netzwerkmodell der gespannten und statisch druckbelasteten Streifenplatte die Formversteifung. Die untersuchten Wandler erreichen eine maximale Kolbenschnelle um 1 m/s.
478

Zobrazování medicínských dat v reálném čase / Medical Data Rendering in Real-Time

Lengyel, Kristián January 2010 (has links)
This thesis deals with design and implementation of an application for medical data imaging in real-time. The first part of project is focused on methods for obtaining data in medical practice and visualization of large volume data on computer using familiar rendering approaches. Similar applications are used outside of medicine in other fields, such as chemistry to display molecular structures or microorganisms. Another part of project will focus on benefits of visualization of volumetric data using programmable hardware and new methods of parallelization of algorithms on graphics card using CUDA technology, and OpenCL. The resulting application will display the volume of medical data based on selected method accelerated by programmable shaders, and time-consuming operations will be paralleled on graphics card.
479

Analýza nejvyššího a nejlepšího využití objektu v bývalém skladovacím areálu v Brně / Analysis of the highest and best use of a former warehouse area in Brno

Bíza, Petr January 2016 (has links)
This diploma thesis focuses on the highest and best use analysis (HABU) of property. In first chapters there is mention about current legislation, theoretical terms and methods of property valuation in Czech republic. The next chapter describes a methodology for the highest and best use analysis. The analysis itself was applied to real case, specifically to a former storage area of the construction company, which is located in Brno - Maloměřice. For this area were designed scenarios of possible use and four of them were chosen using tests of HABU analysis. In the end, one of them was chosen which is being considered the highest and best use for this property.
480

Vad visar den plan som säger mer än tusen ord? : Illustrationsplanens betydelse utifrån tydlighetskravet i Plan- och Bygglagen

Söder, Tove, Eliasson, Erika January 2021 (has links)
Studien syftar till att undersöka illustrationsplaners betydelse som ett förtydligande dokument till detaljplanen, samt i vilken utsträckning illustrationsplaner uppfyller tydlighetskravet i 4 kap 32 och 33 § § Plan- och bygglagen (PBL). Studien har framtagits med avsikt att uppmärksamma en problematik vars effekter kan påverka det faktiska medborgarinflytandet. En brist på forskning har observerats inom ämnet och studien avser därför bidra till att fylla den kunskapsluckan i samhällsplaneringen.  Tydlighetskravet innebär att detaljplanens regleringar tydligt ska redovisas för att säkerställa medborgarnas förståelse för planens innebörd och konsekvenser. I avsikt att uppnå tydlighetskravet används ofta illustrationsplaner som kommunikationsverktyg för att förmedla detaljplanens syfte och planbestämmelser till allmänheten. Detta beror på att detaljplanen ofta kan upplevas svårtydd eftersom detaljplankartans utformning tydligt skiljer sig från hur kartor brukar illustreras i andra sammanhang. Genom kvalitativ innehållsanalys ämnar undersökningen besvara i vilken utsträckning illustrationsplaner uppfyller tydlighetskravet i PBL. Vid undersökningen jämfördes detaljplanekarta och planbestämmelser med tillhörande illustrationsplan för att gradera hur tydliga illustrationsplaner är. Detta genomfördes genom ett antal uppställda påståenden som illustrationsplanen kunde svara mot. Påståendena baseras bland annat på tidigare domslut kring illustrationer samt semiotikens syn på hur bilder kan tolkas. Undersökningen kompletterades med ett antal intervjuer från branschkunniga personer, detta för att få en mer kvalitativ och djupgående förståelse för resultatet samt illustrationsplaners betydelse som kommunikativt verktyg. Undersökningens resultat visar på en bristfällighet hos de undersökta illustrationsplanerna vad gäller tydlighet. Svårtolkade illustrationsplaner försvårar medborgarens möjligheter att uppfatta detaljplanens konsekvenser och deras möjlighet att lämna relevanta synpunkter under planprocessen minskar därmed ytterligare. Denna syn på illustrationsplanens potentiella konsekvenser delades med de personer som intervjuades i samband med studien.  Med undersökningen och intervjuerna som grund har ett antal ställningstaganden och förslag sammanställts som anses inneha praktisk relevans för samhällsplaneringen. Ett exempel på detta är att en mer gedigen vägledning bör tas fram, till förmån för en nationellt enhetligare användning av illustrationer. Vägledningen hade kunnat utformas på olika sätt, bland annat genom att bristfälliga planer sammanställs för att påvisa vilka konsekvenser som kan följa av en otydlig illustrationsplan. Därtill har även annan typ av vägledning samt andra förslag lyfts fram i studiens slutsatser.

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