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Zur Optimierung der Flugzeugkabine in den Bereichen Passagierkomfort und Sicherheit sind Untersuchungen einer Vielzahl neuartiger Kabinenkonzepte notwendig, die angesichts der bestehenden Wechselwirkungen zwischen den grundlegend unterschiedlichen physikalischen Phänomenen eine multidisziplinäre Bewertung erfordern. Die vorliegende Bachelorarbeit beschäftigt sich in diesem Kontext mit der Entwicklung einer Methode zur numerischen Simulation multiphysikalischer, thermisch-strukturakustisch gekoppelter Analysen an unterschiedlich komplexen Modellen der Kabinenseitenwand. Mit Hilfe dieser entwickelten Methoden wird der Einfluss physikalischer Effekte (u.a. Konduktion, Konvektion, durch den Kabinendruck hervorgerufene Belastung des Rumpfes) sowie die Auswirkung konstruktiver Merkmale (ein- bzw. zweischalige Bauweise der Kabinenseitenwand, Einbau von zusätzlichen Dämmmaterialien) auf die Temperaturverteilung und das akustische Transmissionsverhalten im stationären Flugfall untersucht. Die hierbei auftretenden Belastungen, die sich durch eine Druck- bzw. Temperaturdifferenz zwischen Kabine und Atmosphäre ergeben, verursachen jeweils eine Vorspannung im Bauteil. Die unterschiedlichen Vorspannungszustände werden in vorgelagerten statischen Analysen ermittelt, die bei Berücksichtigung thermischer Randbedingungen auch Temperaturfeldberechnungen umfassen. Nachfolgend durchgeführte Modal- und harmonische Analysen liefern die Daten zur Beurteilung des akustischen Transmissionsverhaltens. Aus den Ergebnissen der Simulation geht hervor, dass sowohl die thermische Last als auch die Druckbelastung eine Versteifung des Systems verursachen. Bei gekoppelter Betrachtung der Lasten zeigt sich eine Verstärkung des Versteifungseffekts, der maßgeblich von der thermischen Last dominiert wird. Die Versteifung führt dabei insbesondere im tieffrequenten Bereich bis ungefähr 400Hz bzw. 500Hz zu einer Reduktion der Schalltransmission. Über diesen Frequenzbereich hinaus ist dagegen eine neutrale bzw. negative Auswirkung der Versteifung auf das Transmissionsverhalten zu erkennen. Die Erkenntnisse aus dieser Arbeit zeigen die Komplexität der Interaktionen verschiedener physikalischer Disziplinen und somit die hohe Relevanz und Diversität von multiphysikalischen Analysen für den Flugzeugentwurf.

Günümüzde inşa edilen yüksek katlı yapılardan dolayı, komşu hacimlerin birbirine gürültü iletimi üst seviyeye ulaşmıştır. Özellikle katı doğuşlu gürültü sorununa, inşa bittikten sonra müdahale etmek çok zordur. Bu sebepten dolayı henüz inşa aşamasındayken bina akustiği ölçümleri, bina içinde yaşayan insanların konforlu yaşamları için önemli bir hale gelmiştir. Bu ölçümlerin devlet denetiminde yapılabilmesi için Çevre ve Şehircilik Bakanlığı tarafından "Binaların Gürültüye Karşı Korunması Hakkında Yönetmelik" yayınlanmıştır. Yönetmelikte bahsi geçen ölçümlerin yapılabilmesi için farklı türde bina akustiği ölçüm ekipmanları kullanılmaktadır. Bu çalışmada, bina akustiği ölçümlerinde kullanılan cihaz tiplerinden biri olan, darbe gürültüsü oluşturan cihazın tasarımı gerçekleştirilmiştir. Gerçekleştirilen tasarımda, cihazın, tanımlandığı uluslararası ISO 140140-3 standarta uygun olarak, portatif bir cihaz olması hedeflenmiştir. Bu bağlamda gerçekleştirilen tasarım için kritik tasarım parametreleri belirlenmiş olup, cihazın çalışması esnasında cihaz bileşenlerinde oluşacak kuvvetler sonucunda ortaya çıkacak gerilmelere uygun malzemelerin seçimi yapılmıştır. Malzeme seçimlerinin doğru şekilde yapılabilmesi için üç boyutlu CAD modeli olarak hazırlanan tasarım sonlu elemanlar analizleri ANSYS yardımı ile incelenmiş ve tasarımda optimum şartlar belirlenmiştir. Böylelikle ülkemizde üretimi olmayan bu cihazın temininde, farklı ülkelere olan bağlılığını azaltmasına ön ayak olması amaç edinilmiştir., Today, due to the high-rise buildings constructed, the noise transmission of neighboring volumes to each other has reached a high level. It is very difficult to intervene especially after the construction of the structure-borne noise problem is finished. For this reason, building acoustics measurements during the construction phase have become important for the comfortable lives of the people living in the building. In order for these measurements to be carried out under state supervision, the Ministry issued a regulation. Different types of building acoustics measurement equipment are used for the measurements mentioned in the regulation. In this study, one of the types of devices used in building acoustics measurements, the design of the device that generates impact noise was realized. In the designed design, the device is intended to be a portable device in accordance with the international ISO 140140-3 standard in which it is defined. In this context, critical design parameters have been determined for the design and the materials suitable for the stresses that will occur as a result of the forces that will occur in the device components during the operation of the device have been selected. In order to make the material selection correctly, the design prepared as a three-dimensional CAD model was examined with finite element analysis and the optimum conditions were determined in the design. Thus, the aim of this device, which is not produced in our country, is to pave the way for reducing its loyalty to different countries.

Rezensiert: James A. Steintrager, Rey Chow (Hg.): Sound Objects, Durham, London (Duke University Press) 2019; Britta Herrmann, Lars Korten (Hg.): Diskurse des Sonalen, Berlin (Vorwerk 8) 2019; Kerstin Ergenzinger: Navigating Noise, hg. v. Nathanja van Dijk, Kerstin Ergenzinger, Christian Kassung, Sebastian Schwesinger, Berlin (Verlag der Buchhandlung Walther König)

Problemstellung Die Herausforderungen, vor denen das Messewesen aktuell steht, sind einerseits die Zunahme an Fachbereichen, andererseits der stetige Besucherzahlenrückgang. Die Atmosphäre ist ein relevanter Faktor, um eine größere Besucherzufriedenheit, höhere Wiederbesuchsraten und eine häufigere Weiterempfehlung zu generieren. Daher ist die verstärkte Auseinandersetzung mit dem Stimmungs- und Atmosphärenmanagement bei Messen notwendig. Methode Zur Beantwortung der Forschungsfragen wurde eine Literaturrecherche durchgeführt. Dabei wurde vorwiegend auf Studien der AUMA, Besucherbefragungen und Journals zurückgegriffen. Es wurde sowohl deutsche als auch englische Literatur verwendet, wobei besonders auf die Aktualität der Werke geachtet wurde. Ergebnis Studien zu Folge sind Farben, Beleuchtung, Akustik und Gerüche die wichtigsten Elemente, um eine angenehme Atmosphäre zu schaffen. Besonders relevant ist zudem die multisensorische Ansprache, um möglichst alle Sinne zu stimulieren. Gelingen die Umsetzung und die Ansprache aller Sinne, ist eine angenehme Stimmung, längere Aufenthalte und eine vermehrte Interaktion zwischen den Anwesenden das Ergebnis. Besonders warme Farbtöne, warme indirekte Lichtquellen, Instrumentalmusik und stimulierende Gerüche beeinflussen das Ambiente positiv. Zusammenfassung Die Atmosphäre spielt eine bedeutende Rolle, um den aktuellen Veränderungen entgegenzuwirken. Dem Stimmungsmanagement soll daher mehr Bedeutung zukommen. Dies legt nahe, dass der stimmige Einsatz von Licht, Akustik, Farben und Geruch innerhalb einer Messeveranstaltung notwendig ist. Dabei ist vor allem auf die spezifischen Wirkungen der einzelnen Elemente zu achten und auf die jeweiligen Anforderungen abzustimmen. Problem statement The challenges the trade fair industry is facing are, on the one hand, the increase in the number of specialist areas on offer and, on the other, the steady decline in the number of visitors. According to studies, atmosphere is a relevant factor in generating greater visitor satisfaction, higher revisit rates and more frequent referrals. Therefore, there is a need for increased attention to mood and atmosphere management at trade fairs. Method In order to answer the research questions, a literature research was carried out. The work is mainly based on AUMA studies, visitor surveys and journals. German and English literature was used, with attention paid to the topicality of the sources. Findings According to current studies colors, lighting, acoustics and smell are the most important elements to create a pleasant atmosphere. The multisensory approach is also particularly relevant in order to stimulate as many senses as possible. Therefore, the design concept should include several, coordinated design elements. If the realization and the addressing of all the senses succeed, a pleasant atmosphere, longer stays and an increased interaction between the present is the result. Particularly warm hues, warm indirect light sources, instrumental music and stimulating smells are intended to change the ambience significantly positively. Conclusion The atmosphere plays an important role in the assessment, revisiting and recommendation of a trade fair. The creation of a pleasant ambience should therefore be given more importance. This suggests that the harmonious use of light, acoustics, colors and odors within a trade fair event is necessary. In doing so, the specific effects of the individual elements must be considered and adapted to the respective requirements. eingereicht von: Alice Danglmaier Bachelorarbeit Bad Gleichenberg, Fachhochschule Joanneum 2020

Investigating aeroacoustic sound generation in a measurement is challenging since the flow field needs to be highly resolved in the temporal and spatial domain. Thus, complex aeroacoustic phenomena like the mechanisms of the human voice are still not fully captured scientifically. Recent advances in optical technologies have pushed the limits of measurement resolution and accuracy, making aeroacoustic investigations potentially accessible. Therefore, as a first part of this thesis, a measurement technique is implemented that applies a hybrid acoustic PIV (HAcouPIV) approach. State-of-the-art measurement technology is combined with most recent numerical strategies in the field of acoustics. High-speed PIV is applied to determine the flow velocity, and a numerical approach computes the pressure field based on the measurement data. Then, a perturbation approach is applied to separate the sound pressure from the fluid-mechanical pressure fluctuations. In the second part of the thesis, the HAcouPIV technique is employed to investigate the sound-generating mechanisms and its radiation during human phonation. Thereby, for the first time, the acoustic source field is extracted based on a combination of experimental measurements and numerical simulations. A highly modulated source field that reaches into the supraglottal region was found as the most significant sound-generating mechanism of the phonatory process. This was shown for both broadband and harmonic content. The analysis of the vibroacoustic behavior of the vocal fold oscillation based on laser-vibrometry data revealed strong harmonic content in the glottal region of the superior vocal fold surface. Hence, it potentially contributes to a strong fluid-structure-acoustic interaction especially for the harmonic content. In conclusion, the hybrid approach of laser-based measurement techniques and numerical evaluation procedures was successfully applied. It substantiates the fundamental mechanisms that form the basis of sound generation during phonation. These results suggest to focus on the modulation of the glottal jet and its entire spatial expansion as the main component for sound generation during voiced speech. Die Entstehung von aeroakustisch erzeugtem Schall ist messtechnisch nur eingeschränkt zu erfassen, da eine hohe räumliche und zeitliche Auflösung des gesamten Strömungsfeldes nötig ist. Daher konnten komplexe Schallentstehungsmechanismen - wie bei der menschlichen Stimme - bis jetzt noch nicht vollständig wissenschaftlich erfasst werden. Neue Fortschritte auf dem Gebiet der optischen Technologien hat die Auflösungs- und Genauigkeitsgrenzen in der Messtechnik verschoben, sodass aeroakustische Untersuchungen möglich werden. Auf diesen neuesten Entwicklungen basierend wurde im ersten Teil dieser Arbeit das Verfahren der hybriden Akustik-PIV (HAcouPIV) entwickelt. Aktuellste Messtechnik wird hier mit neuartigen numerischen Verfahren aus dem Gebiet der Akustik kombiniert. Mittels Hochgeschwindigkeits-PIV wird die Strömungsgeschwindigkeit gemessen und mittels eines numerischen Ansatzes daraus das Druckfeld berechnet. Durch einen Störansatz wird dann der Schalldruck von den strömungsmechanischen Druckschwankungen getrennt. Im zweiten Teil dieser Arbeit wird dieser HAcouPIV-Ansatz angewandt, um Schallentstehung und –abstrahlung bei der menschlichen Phonation zu untersuchen. Dabei wird erstmalig das akustische Quellfeld auf Basis eines kombinierten Ansatzes aus experimenteller Messung und numerischer Simulation bestimmt. Ein stark moduliertes Quellfeld, das weit in den supraglottalen Bereich reicht, wurde für normale Phonation festgestellt. Dies wurde sowohl für Breitband-, als auch für harmonische Anteile festgestellt. Die Analyse der vibroakustischen Eigenschaften der Stimmlippenschwingung auf Basis von Laservibrometerdaten offenbarte stark ausgeprägte harmonische Anteile auf der Stimmlippenoberfläche im Bereich der Glottis. Diese haben möglicherweise einen hohen Einfluss auf die Stimmgebung im Rahmen einer Fluid-Struktur-Akustik Interaktion. Ein hybrider Ansatz aus laserbasierten Messmethoden und numerischen Auswerteverfahren wurde in dieser Arbeit erfolgreich entwickelt und angewandt. Grundlegende Mechanismen der Schallentstehung bei der menschlichen Phonation wurden aufgezeigt und neu beleuchtet. Diese Ergebnisse legen die stimmlippeninduzierte Modulation des glottalen Jets und dessen gesamte Ausdehnung als Hauptkomponente im Strömungsfeld für die Schallerzeugung nahe.

Dünya üzerindeki hızlı nüfus artışıyla birlikte giderek artan ve yeni ortaya çıkan birçok problem vardır. Günlük yaşantımızda insanların yaşam kalitelerinin yükselmesi ile birlikte tekstil endüstrisinde akustik konfor önemli bir özellik haline gelmiştir. İnsanların konfor alanlarındaki beklentilerini karşılayabilmek için tekstil üreticilerinin müşteri ürün kalite beklentilerinden taviz vermeden pazardaki zorlu rekabet şartlarında ayakta kalabilmek için ürünlere işlevsellik kazandırması bir gereklilik olmuştur. Bu işlevsellikleri tekstil ürünlerine kazandıracak malzemelerin, süreçlerin araştırılması ve geliştirilmesi kaçınılmazdır. Tekstil sektörünün üzerinde çalıştığı problemlerden biri; sokakta, evde, iş yerinde kısacası günlük yaşantımızın pek çok yerinde karşımıza çıkan gürültü sorunudur. Gürültü, hem zihinsel hem de fiziksel açıdan birçok sağlık sorununu beraberinde getirmektedir. Bunun yanında gürültü kontrolünde kullanılan malzemeler gürültü düzeyinin etkisini azaltmak için yeterli olmamaktadır. Tekstil sektöründe akustik çalışmalarda kullanılan kumaşlar, ağırlıkları ve yüksek maliyetlerine göre yeterli performansı gösterememektedir. Bundan dolayı akustik tekstil ürünleri günlük yaşamda kullanılamamaktadır. Bu tez çalışmasında, literatürdeki gürültü kontrol ve yapı akustiği çalışmalarında kullanılan öz nitelikler analiz edilmiş ve tekstil malzemelerinin sahip olduğu akustik performansı iyileştirecek ürün tasarlanmış, üretilmiş ve test edilmiştir. Akustik malzemenin performansına etki edebilecek farklı malzeme örnekleri kullanılarak optimum değerler yakalanmıştır. Gürültü kontrolüne etki eden farklı akustik parametreleri vardır. Parametrelerin ve tasarlanan üç boyutlu yapının farklı değerlerde göstermiş olduğu akustik performansların doğrulanabilmesi amacıyla akustik ölçüm yöntemleri uygulanmıştır. Çalışma özelinde yapılan ölçümlerde hem ilgili standartlara göre empedans tüpü hem de çalışmada farklı gürültü türleri için malzemenin akustik performansının belirlenmesinde tasarlanan düzenek kullanılmıştır. Düzenekte ölçülen değerlerin doğrulanması empedans tüpü ile gerçekleştirilmiştir. Çalışmalar neticesinde elde edilen tüm numunelerin ölçümünden elde edilen sonuçlar ses dalgalarındaki enerji kayıpları hesaplanarak akustik parametreler iyileştirilmiştir. Çalışmada yapılan frekans ve ses gücü analizlerinde MATLAB sayısal hesaplama programlama dili ve kütüphaneleri kullanılmıştır. There are many ever-increasing and newly emerging problems with rapid population growth in the world. With the increase of people's quality of life in our daily life, acoustic comforthas become an important feature in the textile industry. In order to meet all these expectations in people's comfort areas and survive in challenging competitive conditions in the market without compromising the customer product quality expectations of textile manufacturers, it has become a necessity to bring functionality to the products. It is inevitable to research and develop materials and processes that will bring these functionalities to textile products. The noise we encounter almost everywhere in our daily life, in the street, at home and work, is one of the problems on which textile industry is working on. It brings with it many health problems both mentally and physically. Therefore, noise control studies become more of an issue. Besides, materials used in noise control are not sufficient to reduce the effect of the noise level. The fabrics used in acoustic studies in the textile industry do not show sufficient performance according to their weight and high cost. Thus, acoustic textile products can not be used in daily life. In the thesis study, the attributions used in the noise control and building acoustics studies in the literature were analyzed and the product with the highest damping value that a textile material will have was designed, manufactured and tested. Optimum values were obtained by using different material samples that may affect the performance of the acoustic material. Acoustic measurement methods should be applied to verify the acoustic performances shown by the parameters and the designed three-dimensional structure at different values. In the measurements made in the study, the device designed for determining the acoustic performance of the material for both the impedance tube according to the relevant standards and the different noise types in the study was used. In addition, sound records of noise types encountered in daily life are taken and applied to the acoustic absorbent fabric with the aid of the device, and the results are examined. MATLAB numerical computing programming language and libraries were used in the frequency and sound power analyses made in the study. Harput Tekstil Sanayi ve Ticaret A.Ş

Bakgrund: Lungcancer är en av de cancerformer med sämst prognos, vilket delvis förklaras av sen diagnos. Potentiellt kan cirkulerande extracellulära vesiklar, som diagnoskälla och screeningverktyg, möjliggöra tidigare diagnostik och därmed förbättra den annars dåliga prognosen. Syfte: Syftet var att undersöka om det är möjligt att, genom kvantifiering av extracellulära vesiklar, urskilja malign från benign lungsjukdom samt lungsjuka från friska. Vesiklarna isolerades med akustik för att bedöma dess användbarhet som framtida diagnostiskt verktyg. Metoder: Plasmaprover togs från forskningspersoner med malign (n =5) respektive benign (n=5) lungsjukdom samt frisk kontrollgrupp (n = 10). Grupperna med malign och benign lungsjukdom matchades utifrån kön, ålder (åldersspann ± 1 år) och rökstatus (fyra av fem par matchade). Vesiklarna isolerades genom akustik med AcouTrap och analyserades därefter med Nanoparticle Trackning Analysis (NTA). Resultat: Repeterbarheten uttryckt i variationskoefficienten (CV) vid isolering med AcouTrap hade medelvärdet 18,3% gällande koncentration och 3,7% gällande storlek medan NTA-analys hade medelvärdet 12,9% gällande koncentration och 3,2% gällande storlek. Mediankoncentrationen hos lungsjuka var 4,7x1013 partiklar/ml jämfört med 5,1x1012 partiklar/ml hos friska individer (p=0,005). Medianstorleken vid malign lungsjukdom var 74,4 nm jämfört med 68,0 nm vid benign lungsjukdom (p=0,08). Slutsatser: Trots det fåtal patientprover som analyserats observerades en statistiskt signifikant skillnad i antalet extracellulära vesiklar mellan lungsjuka och friska samt en icke-signifikant trend som visade större partiklar hos de med malign lungsjukdom än benign lungsjukdom. Akustik som isoleringsmetod av extracellulära vesiklar hade hög repeterbarhet och således kan metoden bli ett bra framtida kliniskt verktyg.

Spreading news has been one of the main functions of the internet from its very beginnings. As early as the beginning of the 1980s newspaper publishers started to offer news not just on paper, but online. This serves us as the starting point to scrutinize web journalism. Referring to certain moments in the history of e-newspapers and their utilization of more and more web and social media services, we want to investigate how the change in journalism epitomizes certain characteristics of the internet—or, to be more precise, how certain misconceptions of what e-papers are and of what the internet is overlap. Aiming for a better understanding of today’s digital culture we try to develop an idea of what we call the “acousticness,” or “noisiness,” of the internet, as opposed to the internet’s common conceptualization in visual terms.

Diese Arbeit wurde im Rahmen des am AIT - Austrian Institute of Technology durchgeführten Forschungsprojekts SilentAirHP durchgeführt, das die Reduktion von Schallemissionen von Luft/Wasser-Wärmepumpen zum Ziel hat. In diesem Projekt wird ein akustischer Dom mit 64 Mikrofonen verwendet, um frequenz-, zeit- und raumaufgelöste akustische Daten zu erfassen. Exakte Koordinaten aller 64 Mikrofone werden zur Sicherstellung der Reproduzierbarkeit der Messungen, als Grundlage für andere Algorithmen (z.B. Schallleistungspegelanalyse) und zu Visualisierungszwecken (Plots und Augmented-Reality-Anwendungen) benötigt, sind aber von Hand nur schwer und ungenau zu erhalten. Um die Position dieser Mikrofone, d.h. ihre Raumkoordinaten, automatisch und effizient zu bestimmen, wird eine akustische Lösung unter Verwendung von Multilateration und Time Difference of Arrival entwickelt. Multilaterationsberechnungen verwenden Entfernungen zwischen mehreren Objekten, um relative Koordinaten zwischen diesen Objekten zu erhalten, ähnlich wie bei (satellitengestützten) Navigationssystemen wie GPS. Die Problemlösung soll modular und unabhängig von der Hard- und Softwareumgebung, dem Messverfahren und der Anwendung nutzbar gemacht werden. Das Berechnungsverfahren beginnt mit der Wiedergabe von vorgegebenen Samples auf Lautsprechern mit bekannten Koordinaten und der Aufzeichnung der Mikrofondaten. Durch die Korrelation der gesendeten mit den aufgezeichneten Daten ist es möglich, Zeitverschiebungen zu extrahieren, die durch unterschiedliche Abstände von jedem Mikrofon zu jedem Lautsprecher verursacht werden. Diese Zeitverschiebungen, die genau bekannten Lautsprecherkoordinaten und die temperaturabhängige Schallgeschwindigkeit werden als Input für den Multilaterationsalgorithmus verwendet, der die Koordinaten der Mikrofone zurückgibt. Zu den durchgeführten Aufgaben gehörten daher: Literaturrecherche, Entscheidung über die zu verwendende Hard- und Software, Entwurf des optimalen Lautsprecherausgangssamples, Entwicklung einer stabilen Anwendung, die auch von Personen ohne Programmiererfahrung verwendet werden kann, Verwendung robuster Algorithmen zur Aufzeichnung und Vorverarbeitung von Audiodaten, Implementierung von Datenkorrelationsmethoden und des Multilaterationsalgorithmus. Zusätzlich musste das Verfahren gründlich getestet und in den bestehenden Arbeitsablauf implementiert werden, einschließlich Datenerfassung, Analyse und Visualisierung. Für Messungen mit Sichtverbindung der Lautsprecher zum Mikrofon funktioniert das System innerhalb der geforderten Genauigkeiten, aber die Leistung lässt in Umgebungen mit zu vielen Mehrwegeffekten (Reflexion und Beugung) nach, was zu nicht wiederherstellbaren Informationsverlusten führt. SilentAirHP wird im Rahmen des Energieforschungsprogramms des Klima- und Energiefonds (5148527) unterstützt, das vom österreichischen Bundesministerium für Verkehr, Innovation und Technologie initiiert wurde., This thesis has been done in the framework of the SilentAirHP research project conducted at AIT - Austrian Institute of Technology, which aims to reduce the sound emission of air-to-water heat pumps. In this framework, an acoustic dome with 64 microphones is used to capture frequency-, time-, and space resolved acoustic data. Exact coordinates of all 64 microphones are needed to ensure reproducibility of measurements, as foundation for other algorithms (e.g. sound power level analysis) and for visualization purposes (plots and augmented reality applications), but are difficult and imprecise to produce by hand. In order to automatically and efficiently determine the position of these microphones, i.e. their spatial coordinates, an acoustic solution using multilateration and Time Difference of Arrival is being developed. Multilateration calculations use distances between multiple objects to obtain relative coordinates between those objects, similar to (satellite-based) navigation systems, such as GPS. The problem solution should be made modular and usable independent of the hard- and software environment, measurement procedure, and application. The calculation procedure starts by playing predetermined audio samples on speakers with known coordinates and recording the microphone data. By correlating the sent with the recorded data, it is possible to extract time offsets, which are caused by different distances from each microphone to each speaker. These time offsets (or 'delays'), the precisely known speakers' coordinates, and the temperature-dependent speed of sound are used as input for the multilateration algorithm, which returns the microphones' coordinates. Tasks therefore included: researching literature, deciding on hardware and software to use, designing the optimal speaker output sample, developing a stable application to be used by people without programming experience, using robust algorithms to record and pre-process audio data, implementing data correlation methods and the multilateration algorithm. Additionally, the procedure had to be tested thoroughly and implemented in the existing workflow, including data acquisition, analysis and visualization. For measurements in line of sight the system works within the accuracy required for the application, but performance degrades in settings with too many multipath effects (reflection and diffraction), which causes unrecoverable loss of information. SilentAirHP is supported in the framework of the Energy research program of the Climate and Energy Fund (5148527) initiated by the Austrian Ministry for Transport, Innovation and Technology.

Yaşlılıkla birlikte tüm vücutta gözle görülen yaşlanma etkileri aynı şekilde seste de görülür. Yaşanan anatomik ve fizyolojik değişimler sesin akustik, algısal ve aerodinamik özelliklerinin de değişmesine neden olur. Bu çalışma 60 yaş ve üzeri 47'i kadın 49'u erkek olmak üzere toplam 96 katılımcıyla yapılmıştır. Yapılan bu çalışmayla birlikte geriatrik popülasyonun akustik, algısal ve aerodinamik özelliklerinin betimlenmesi amaçlanmıştır. 96 katılımcıdan akustik ölçümler için F0, Jitter, Shimmer, HNR; algısal değerlendirme için SEÖ, SİYKÖ, GRBAS; aerodinamik ölçümler için ise s/z ve maksimum fonasyon süresi değerleri ölçülmüştür. Toplanan veriler yaş ve cinsiyete göre değerlendirilip karşılaştırılmıştır. Bunun sonucunda akustik ölçümlerde cinsiyet değişkenine göre istatistiki açıdan anlamlılık bulunmuş, yaşlı kadınlarda yetişkin kadınlara göre temel frekansta artış, yaşlı erkeklerde ise yetişkin erkeklere göre temel frekansta düşüş gözlemlenmiştir. Algısal ölçümlerde cinsiyet ve yaş değişkenine göre istatistiki açıdan anlamlılık bulunmuş, cinsiyet değişkenine göre bakıldığında yaşlı erkeklerde GRBAS skalasının pürüzlülüğü tanımlayan R parametresinin yüksek, yaşlı kadınlarda ise GRBAS skalasının güçsüzlüğü tanımlayan A parametresinin yüksek olduğu; SEÖ ve SİYKÖ ölçeklerinde yaşlı erkeklerin daha yüksek skorlara sahip olduğu gözlemlenmiştir. Yaş değişkenine bakıldığında ise 70+ yaş grubundan GRBAS skalasının güçsüzlüğü ifade eden A parametresi yüksek bulunmuştur. Aerodinamik değerlendirmelerde ise yaş değişkenine göre istatistiki açıdan anlamlılık bulunmuştur (p

Yüksek Lisans Tezi, Geçmişi milattan önceki yıllara dayanan gösteri salonları, müziğe ve tiyatroya ilginin artmasıyla işlevini geliştirerek açık tiyatrolardan özel gösteri salonlarına dönüşmüştür. Günümüzde gösteri salonlarındaki en önemli girdi dinleyici/izleyicinin konforu haline gelmiştir. Şüphesiz bir gösteri salonu tasarlanırken mimarın amacı müziği, gösteriyi veya konuşmayı özellikleri kaybolmadan dinleyiciye iletmek olmalıdır. Bu kaygılar akustik biliminin ortaya çıkarak önem kazanmasını sağlamıştır. Akustik bilimi, bir gösteri salonu için işitsel konforu ihtiva eder. İşitsel konfor ise salonun mimari tasarım aşamasından itibaren başlayan bir olgudur. Akustik konforu sağlayacak olan estetik koşullar ve yatay-dikey donatıların bir araya getirilmesiyle de tasarlanan hacim başarıya ulaşmaktadır. Bu bağlamda bu tez çalışmasının amacı gösteri salonları tasarım ilkelerinin belirlenmesidir. Tasarım ilkelerinin sistematik derleme ile kategorize edilmesi ve tablolara aktarılarak değerlendirme listesinin oluşturulması hedeflenmiştir. Bu kapsamda öncelikle akustik gerekliliği olan mekânların tasarım sürecini etkileyen işitsel kavramların tanımları ve iç mekân yapı akustiği ele alınmıştır. Sonrasında mimari ve akustik tasarımın birbiriyle olan ilişkisi incelenmiştir. Bunun yanı sıra gösteri salonlarının tasarım ilkeleri niteliksel verilerle araştırılmıştır. Bütün bu veriler ışığında, yapı yönetmelikleri, standartlar ve mimari tasarım kriterleri kapsamında gösteri salonlarının tasarım ilkeleri tablosu oluşturulmuştur. Bu ilkeler tez çalışmasının son bölümünde örneklem alan ile kıyaslanmıştır. Bunun sonucunda bir gösteri salonu tasarımının mekânsal, yapısal, gürültü kontrolü ve akustik kusurların giderilmesi girdileri ile şekillendiği ispatlanmıştır., Within the increasing of interest in the music and theater, the show halls, which have a history dating back to the years before Christ, have developed their functions and transformed from open-air theaters to private show halls. Nowadays, the significant factor in the show hall has become the comfort of the listener / audience. When designing a show hall, the aim of the architect should be to convey the musical sounds, show or speech to the audience without losing its content. These concern has enabled the science of acoustics to emerge and gain importance. The science of acoustics includes auditory comfort for a show hall. Auditory comfort is a phenomenon that begins from the design stage of the show hall. The designed volume, by combining the aesthetic conditions and horizontal-vertical reinforcements that will provide acoustic comfort, successful accomplished. Therefore, the main purpose of this study is that the design principles of the show halls were comprehensively determined. It was aimed to categorize the design principles with systematic compilation and to create the evaluation list. In this context, primarily definitions of acoustic concept that show halls affecting the design process and interior building acoustics were discussed. Then, the relationship between architectural and acoustic design was examined. In addition, the design principles of the show halls have been researched with qualitative data. According to the all these data, the design principles table of the show halls has been created within the scope of building regulations, standards and architectural design criteria. These principles have been comprehensively compared with the sampling area in the last section of the study. As a result, this study was proven that a show hall design is shaped by spatial, structural, noise control and removal acoustic defects data.

The performance of resultant topological structure of Kohonen Self Organizing Map SOM is highly dependent of the learning rate and neighborhood parameters. In literature there are plenty many different types of approaches to and proposals for those parameters. It has been investigated that in general the learning rate and neighborhood parameters are data independent and predefined before the training period. Here in this paper a novel approach has been proposed to change the learning rate parameter according to the interaction of neurons with data. During training, the worst matching neuron also tracked and used to trace the formation of topological structure of SOM. A slight modification on conventional learning rate with proposed method has a considerable influence on resultant topologies in a positive way. The effects of this approach have been tested with the real world problem and different synthetic data.

The role of air transport in transportation system is increasing every year. However, there can be difficulties to meet this increase. Therefore, efforts to resolve the problems in air transport become important. Delays and congestions are seen in the air transport system are among these problems. Airports are one of the most critical points of air transportation system facing these problems. One of the measures to be taken to resolve this problem is improving the existing system. Istanbul Ataturk Airport, the busiest airport in Turkey, often experiences delay and congestion problems. To propose a solution to these problems and to reduce runway occupancy time in Istanbul Ataturk Airport, additional fast-exit taxiways to the runway 05 were constructed. In this study, the impact of infrastructure changes made in Istanbul Ataturk Airport is examined, and traffic flow and capacity analysis is carried out comparing three different runway configurations. In consequence of the construction of additional fast-exit taxiways to the runway 05, airport capacity has increased 1.9 per cent. It is also shown that the high average delay time reduces airport capacity.

Der selbsternannte Sachverständige Johannes Salim Ismaiel-Wendt untersucht Techniken und Technologien des Rechtsprechens – Apparatives genauso wie rhetorische Strategien. Er konzentriert sich in seinem Bericht auf Mikrofonie und damit verbundene Übertragung und Verstärkung, denn diese reflektiert und situiert Sprechen und Hören im Gerichtsverfahren in besonderer Weise. Das auditive Setting ist zu verstehen als «Symptom und Effekt historisch spezifischer epistemischer Konstellationen» (Gießmann 2009). Am technischen Aufbau, der Verkabelung und den Schaltmöglichkeiten sind Sprech- und Hörordnungen sowie Machtpositionen zu erkennen – und diese sind umkämpft., The self-proclaimed expert Johannes Salim Ismaiel-Wendt examines techniques and technologies of the jurisprudence – apparatuses as well as rhetorical strategies. In his report he concentrates on microphony, transmission and amplification, because it reflects and situates speaking and hearing in court hearings in a special way. The auditory setting is to be understood as the «symptom and effect of historically specific epistemic constellations» (Gießmann 2009). Technical set-ups and wiring regulate and harden orders of speech, listening and power positions - and these positions are contested.

Thiophene belongs to a class of heterocyclic compounds. In this study, three new dimethyl-5-hydroxy isophtalate derived thiophene esters were successfully synthesized and characterized by FT-IR, Elementel Analysis, 1H-NMR, 13C-NMR and HRMass techniques. Synthesized compounds antimicrobial effects were tested on Staphylococcus aureus (ATCC 25923); Enterococcus faecalis (ATCC 29212); Enterococcus faecalis (ATCC 51922); Klebsiella pneumoniae (ATCC 700603); Pseudomonas aeruginosa (ATCC 27853); Escherichia coli (ATCC 35218); Escherichia coli (ATCC 25922) and Candida albicans (ATCC 90028); Candida glabrata (ATCC 90030); Candida krusei (ATCC 6258); Candida parapsilosis (ATCC 22019). Compound C1 showed the highest antimicrobial activity, possessing the same potential as chloramphenicol against, P. aeruginosa ATCC 27853. According to MTT assays, this compound (C1) was identified as non-toxic.

research Thermoluminescence study on nitrogen doped Tl2Ga2S3Se single crystals was achieved by performing the experiments with different stopping temperatures of 10?24 K and various heating rates between 0.4 and 1.2 K/s below room temperature. Thermoluminescence peak with peak maximum temperature of 54 K was detected from the emitted luminescence. Two trap levels were obtained from the observed spectra. Curve fitting and initial rise methods were applied to compute the activation energies and the values of 34 ± 2 and 70 ± 4 meV were found. Thermal cleaning process was applied to separate the overlapping peaks and so true energy region of trapping levels was corroborated. Moreover, variations of shape and position of TL curve were studied by investigating the heating rate behavior of trap levels. The best known behavior which the peak maximum temperature increases while the thermoluminescence intensity decreases with raising heating rate was observed. The effect of the N doping on the existed defects was discussed.

Dissertation, RWTH Aachen University, 2019; Berlin : Logos Verlag Berlin GmbH, Aachener Beiträge zur Akustik 30, 1 Online-Ressource (III, 151 Seiten) : Illustrationen, Diagramme (2019). = Dissertation, RWTH Aachen University, 2019, While binaural technology applications gained in popularity in recent years, the majority of applications still use non-individual Head-Related Transfer Functions (HRTFs) from artificial heads. These datasets enable a reasonably good spatial localization which works especially well when using an additional visual cue. However, certain applications, for example research of spatial hearing or hearing attention, require an physically exact and realistic binaural signal. Moreover, it was shown in many experiments that there is a substantial gain from the use of individual HRTFs, for example in localization tasks. The limiting factor that prohibits the widespread use of individual HRTFs is the acquisition of such data. A substantial hardware requirement obstructs a more universal usage. Even for institutions that allow individual measurements, the measurement time that is required, and that the subjects are required to remain motionless made most measurements unfeasible in the past. This time requirement has recently been reduced by the use of parallelization in the measurement signal which lead to the development of fast measurement systems capable of acquiring individual and spatially dense HRTF. This thesis provides a objective and subjective evaluation of such a system that is designed with the goal of little disturbance of the measurements in mind. The construction is detailed, followed by both an objective and subjective evaluation. A detailed investigation into additional distortion of the sound field introduced by the system itself is presented and it is shown that the system performs comparably to a conventional system in terms of sound source localization. Furthermore, a method is introduced and evaluated to further reduce the measurement time by using continuous rotation during the measurement. This method is used to reduced the measurement duration from eight minutes to three minutes without audible differences. The introduced methods are also used to reducing additional errors from subject movement. It is shown that this movement can be reduced by a visual feedback system to a level that can be compensated efficiently., Published by Logos Verlag Berlin GmbH, Berlin

Otomatik konuşma tanıma sistemleri, konuşma seslerinin metne geçirilmesine yarar. Herhangi bir dilde otomatik konuşma tanıma sisteminin performansı, konuşmacı cinsiyeti ve duygu durumunun yanı sıra dilin varyantları olan ağızlara da bağlıdır. Ağızlar aynı coğrafik bölgede yaşayan insanların konuştuğu, söyleyiş biçimi ve sözcüksel yapı olarak birbirine benzeyen ve diğer bölgelerde konuşulan ağızlardan, sayılan bu özellikler bakımından ayrılan günlük konuşma biçimleridir. Ağız tanımanın amacı sesli ifade özelliklerinden insanların ağızlarının belirlenmesidir. Ağzın tanınmasının ardından dil ve akustik modellerin bu ağza adapte edilmesiyle konuşma tanıma sisteminin başarımının arttığı bilinmektedir. Ayrıca sesli ifadeden konuşulan ağzın belirlenmesi; sesli yanıt sistemlerinde ön işlem adımı olarak veya adli bilişimde ipucu elde etmede kullanılabilir.Ağız tanımada kullanılan modelleme teknikleri farklı dil katmanlarındaki bilgiyi modellemeye yöneliktir. Akustik, fonotaktik ve prozodik katmanlarındaki öznitelikler insanların konuştuğu ağza özgü önemli bilgiler vermektedir. Konuşmanın fonetik farklılıkları, fiziksel düzeyde spektral öznitelikleri incelenerek tespit edilebilmektedir. Klasikleşmiş Mel Frekans Kepstral Katsayıları (MFCC) ve Log mel-spektrogram gibi öznitelikler bu amaçla kullanılmaktadır. Fonotaktik, bir dilde/ağızda, fonemlerin bir arada bulunma kurallarına karşılık gelmektedir. Fonem dizilimleri ve bu dizilimin sıklığı ağızdan ağza değişiklik göstermektedir. Fonem dizilimleri fonem tanıyıcılar yardımıyla elde edilmekte ve daha sonra dil modelleriyle fonem dağılımları çıkartılmaktadır. Prozodi, konuşmanın tonlama, vurgu ve ritim gibi işitsel öznitelikleridir. Bu özniteliklerin insanın konuşmayı algılamasında anahtar rol üstlendiği bilinmektedir. Bu algısal öznitelikler fiziksel düzeyde temel frekans (perde), enerji ve sürenin ölçülmesiyle elde edilmekte ve uygun parametrik gösterimlere çevrilmektedir. Son yıllarda, derin sinir ağlarının popüler hale gelmesiyle birlikte Konvolüsyonel Sinir Ağları (CNN) özellikle görüntü ve konuşma tanımada sıklıkla kullanılmaktadır. Bunun yanı sıra Uzun Kısa-Dönem Bellekli (LSTM) yinelemeli sinir ağları dizi sınıflandırma ve dil modelleme problemlerinde çokça kullanılmaktadır. LSTM sinir ağları, uzun dönemli bağlam bilgisini modellemede n-gram modellerden daha başarılıdır.Türkiye'nin farklı yörelerinde yaşayan insanların konuştuğu ağızlar yukarıda bahsedilen özellikler açısından birbirinden ayrılmaktadır. Bu bakımdan, bu tez çalışmasında akustik, fonotaktik ve prozodik öznitelikler kullanılarak Türkçenin ağızlarının CNN ve LSTM sinir ağlarıyla sınıflandırılması konu edilmiştir. Bu amaçla Ankara, Alanya, Kıbrıs ve Trabzon ağızlarından oluşan bir Türkçe veri kümesi oluşturulmuştur. Önerilen yöntemler Türkçe veri kümesi üzerinde sınanmış ve yorumlanmıştır. Çalışma sonucunda, kullanılan yöntemlerin Türkçe ağız tanıma için oldukça iyi sonuçlar verdiği gözlenmiştir. Automatic speech recognition systems are used to translate speech sounds into text. The performance of the automatic speech recognition system in any language is dependent on the speaker gender and emotion as well as dialects that are variants of the language. Dialects are the speech forms that are similar to each other in the same geographic region as the utterance and lexical structure. With these characteristics, dialects are separated from each other. The aim of the dialect recognition is to identify the humans' dialect from their speech. Following the recognition of the dialect, it is known that the performance of the speech recognition system is enhanced by adapting the language and acoustic models to this dialect. Furthermore, identifying spoken dialect from speech can be used as a preprocessing step in voice response systems, or it can help to obtain a clue in forensics.The modeling techniques used in dialect recognition are intended to model information in different language layers. Features in the acoustics, phonotactic and prosodic layers give important information that specific to the dialect. Phonetic differences of speech can be determined by examining their spectral features at the physical level. Features such as classical Mel Frequency Cepstral Coefficients (MFCC) and Log mel-spectrogram are used for this purpose. Phonotactic corresponds to the rules of coexistence of phonemes in a language/dialect. Phoneme sequences and the frequency of this sequence vary from dialect to dialect. Phoneme sequences are obtained by phoneme recognizers and then phoneme distributions are extracted using language models. Prosody is the auditory features of speech such as intonation, stress and rhythm. It is known that these features play a key role in the human perception of speech. These perceptual features are extracted by measuring the fundamental frequency (pitch), energy and duration at the physical level and converted into appropriate parametric representations.In recent years, Convolutional Neural Networks (CNNs) have been frequently used particularly in image and speech recognition since deep neural networks become popular. In addition, Long Short-Term Memory (LSTM) recurrent neural networks are widely used in sequence classification and language modeling problems. LSTM neural networks are more successful in modeling long-term context information than n-gram models.Dialects spoken by people living in different regions of Turkey are separated from each other in terms of features mentioned above. From this perspective, in this thesis, acoustics, phonotactic and prosodic features were used to classify Turkish dialects with CNN and LSTM neural networks. For this purpose, a Turkish data set consisting of Ankara, Alanya, Kıbrıs and Trabzon dialects was formed. The proposed methods have been tested and interpreted on the Turkish data set. As a result of the study, it was observed that the methods used gave very good results for Turkish dialect recognition. 118

Bu çalışmada Öklidyen 3-uzayındaki Hasimoto yüzeyleriincelenmiştir. İlk olarak, Öklidyen 3-uzayındaki Hasimoto yüzeyleriningeometrik özellikleri incelenmiştir. Özellikle Bishop çatısı ile ilişkilendirilmişbu yüzeylerin eğrilikleri elde edilmiştir. Daha sonrasında bu yüzeylerin Bishopçatısına göre parametre eğrilerinin bazı karakterizasyonları verilmiştir., In this paper, weinvestigate the Hasimoto surfaces in Euclidean 3- space. Firstly, weinvestigate the geometric properties of these surfaces in Euclidean 3-space.Especially, we obtain the curvatures of Hasimoto surface according to Bishopframe. Then we give some characterization of parameter curves obtainedaccording to Bishop frame of Hasimoto surfaces.

Common rail sistemi günümüz dizel motorlarında kullanılan yüksek teknolojili bir yakıt enjeksiyon sistemidir. Performans, verimlilik, gürültü oluşumu ve emisyon oluşumu ele alındığında diğer yakıt besleme sistemlerinden daha üstün özelliklere sahiptir. Ancak performans, verimlilik ve emisyon hedeflerini yakalanması için yakıt sistemi basınçları geçmişten günümüze sürekli artmıştır. Artan yakıt sistemi basıncı enjektör ömrünü negatif etkilediği için bu etkilere karşı kritik parçalarda ilave önlemler alınmaktadır.Bu tez çalışması ile enjektörde yüksek basınç bölgesi ile alçak basınç bölgesi arasında valf görevini yerine getiren ve yüksek basınç farkının ortaya çıkardığı kavitasyona en çok maruz kalan parçalardan biri olan valf parçasının kaplama kalitesinin tayini için akustik kavitasyon yöntemiyle yeni bir ölçüm metodu geliştirilmesi hedeflenmiştir.Bu tez çalışmasında valf parçası için mevcut kaplama kalitesi testleri olan HF (Haftung-Adhesion Test), Scratch testi gibi yöntemlerin yetersiz kaldığı, valf parçasının saha şartlarına daha uygun bir metot olan akustik kavitasyona maruz bırakılarak, homojenlik kontrolünün de yapılabildiği ve değerlendirme riskini minimize eden yeni bir test metodu geliştirilmiştir. İlk aşamada sonotrode cihazının oluşturduğu kavitasyon bulutunun karakteristiği incelenmiştir. İkinci aşamada basit bir geometriye sahip alüminyum numunelerle sonotrode başlığı arasında farklı mesafelerde testler yapılıp kavitasyon bulutunun mesafeye bağlı etkileri incelenmiştir. Sonraki aşamada valf parçası ile aynı testler yapılarak en yüksek aşınmanın elde edildiği optimum mesafe belirlenip son aşamada kaplama kalitesinin ayırt edilebileceği sınırlar belirlenmiştir.Test sonuçları değerlendirildiğinde common rail enjektörün en kritik parçalarından biri olan valf parçasının kaplama kalitesi değerlendirilmesine yönelik saha şartlarına uygun yeni bir test metodu geliştirilmiştir. Common rail system is a high-tech fuel injection system used in today's diesel engines. Compared to the other injection systems, the common rail system has advantages in terms of performance, efficiency, noise generation and emissions. However, fuel system pressures have continued to increase from the past to the present, in order to achieve performance, efficiency and emission targets. Since increased fuel system pressure has a negative effect on the injector life, additional measures are taken in critical parts.In this study, it is aimed to develop a new test method by acoustic cavitation method for the determination of the coating quality of the valve piece which is one of the most exposed parts of the cavitation caused by the high pressure difference between the high pressure zone and the low pressure zone in the injector.In this study, since the existing coating quality tests of the valve piece such as HF (Haftung-Adhesion Test), Scratch test are inadequate, a new test method has been developed that can control homogeneity and minimizes the risk of evaluation by using acoustic cavitation which is a more suitable method considering the field conditions. In the first step, the cavitation cloud characteristics formed by the sonotrode device were investigated. In the second step, the tests were carried out at distance varies between the aluminum samples with a simple geometry and the sonotrode head. The cavitation cloud effects on the distance were examined. In the next step, the same tests were carried out with the valve piece and the optimum distance with the highest wear was determined. In the final stage, the limits for distinguishing coating quality were appointed.According to the test results, a new test method for the evaluation of the coating quality of the valve part which is one of the most critical parts of the common rail injector has been developed in accordance with the field conditions. 71

As cities grow and densify, the amount of traffic in and through settlement also increases. Horizontal surfaces are increasingly disappearing in favor of housing and infrastructure. This leads to increased noise levels and increased emissions in both residential and green belts. Where exploitation cannot be adapted in any other way, or where natural shielding against noise cannot be achieved, noise screens are often erected to minimize noise propagation from roads and railways. The most commonly occurring noise screen today consists of wood, but given its prerequisites, the study intends to investigate whether noise screens in concrete can be a better alternative. The purpose is thus to design and dimension noise screens in concrete. The study is carried out in collaboration with Butong AB, which since 2009 has developed and constructed plant walls in concrete. The objective is to construct and dimension a self-supporting noise shield, with integrated substrate for plants to grow and germinate, based on Butong's existing plant walls. To achieve the report's objectives, different types of matrices and designs have been evaluated with respect to strength and mechanical properties. The calculations made are numerical and performed in SolidWorks. The results from the numerical tests have been used to produce a noise shield with intended dimensions and where loads have been applied according to current eurocodes and SIS standards. The conclusion indicates that green noise screens in concrete maintain a high competitiveness against noise screens in wood. The long span, good mechanical properties and aesthetically pleasing design are some of the factors that support the conclusion.

Due to the electrification of cars and the reduction of noise generated by the powertrain, the automotive industry has gained growing interest for computer-based acoustic design of HVAC systems. In order to implement tools for virtual noise reduction, it is necessary to develop simulation procedures that are able to reliably predict the aeroacoustic noise of HVAC systems and their components. For this purpose, a hybrid simulation technique was proposed and tested in this work: First of all, the non-stationary flow was computed by use of a common finite volume solver; subsequently, the aeroacoustic sources were evaluated; finally, the sound radiation was simulated by a finite element code. The coupling procedure between these simulation steps is a crucial task to achieve excellent results, for which two aeroacoustic approaches were tested. Applying Lighthill's analogy was able to yield spectra in good agreement with experiments. However, the effort required for the implementation and acoustic simulation was high, while the possibilities for source analysis were limited. These problems did not occur when the acoustic perturbation equations (APE) in form of the perturbed convective wave equation (PCWE) were used. This approach provides insight into the pure sound source and propagation fields. However, it was found to be more sensitive regarding numerical noise and the truncation of sources. Based on these findings, this work revealed how the proposed procedure can be used to successfully predict the far-field noise spectra of a generic air outlet, a real air outlet of a car, an HVAC unit, a centrifugal fan, and eventually a complete HVAC system. Therefore, this work demonstrated the applicability of hybrid approaches for the prediction of HVAC noise. Furthermore, details on their correct usage are provided to enable the error diagnostics of aeroacoustic simulations also in other fields of application. These findings offer the basis for the development of computer-based acoustic design tools for HVAC systems and thus pave the way for further improvements regarding practical usage., Mit zunehmendem Einsatz von Elektromotoren im Automobilbau sowie durch Maßnahmen zur Geräuschreduktion im herkömmlichen Antriebsstrang hat das Interesse am Klangdesign von PKW Klimatisierungsgeräten zugenommen. Dieser Aspekt wird bisher jedoch nicht im computergestützten Entwicklungsprozess berücksichtigt. Hierzu sind verlässliche Methoden zur Schallvorhersage von Klimatisierungsgeräten und deren Komponenten notwendig. Zu diesem Zweck wurde in dieser Arbeit ein hybrider Simulationsansatz vorgeschlagen und getestet: Im ersten Schritt wurde das instationäre Strömungsfeld berechnet. In einem Zwischenschritt wurden die strömungsinduzierten Schallquellen bestimmt und zum Schluss die akustische Schallausbreitung simuliert. Die Kopplungsstrategie bzw. Quelltermberechnung zwischen beiden Simulationsschritten ist entscheidend um exzellente Ergebnisse zu erhalten. Dazu wurden zwei aeroakustische Ansätze verfolgt. Der erste Ansatz war die Analogie von Lighthill, die zu Schallspektren in guter Übereinstimmung mit den Experimenten führte. Dabei haben sich die komplexe Implementierung der korrekten Randbedingungen und die fehlende Trennung von Strömung und Akustik als nachteilig erwiesen. Dieses Verhalten konnte bei Anwendung von akustischen Störungsgleichungen (APE) nicht festgestellt werden, was am Beispiel der gestörten konvektiven Wellengleichung (PCWE) gezeigt wurde. Diese Vorgehensweise ermöglicht einen Einblick in das reine akustische Quell- und Ausbreitungsfeld. Nachteilig erwies sich hier jedoch das ausgeprägtere numerische Rauschen sowie die Sensitivität bzgl. abgeschnittenen Quellregionen. Auf Basis dieser Erkenntnisse konnte gezeigt werden, wie die Schallspektren im Fernfeld eines vereinfachten Ausströmers, eines realen PKW-Ausströmers, einer Klimageräteeinheit, eines Radialgebläses und schließlich einer Gesamtklimaanlage erfolgreich vorhergesagt werden können. Die Ergebnisse dieser Arbeit demonstrieren die Anwendbarkeit hybrider Ansätze für die Vorhersage von Strömungsschall in PKW-Klimaanlagen. Darüber hinaus werden Details bezüglich ihres korrekten Einsatzes erläutert, wodurch die Fehlerdiagnose von aeroakustischen Simulationen auch in anderen Anwendungsfeldern vereinfacht wird. Die Erkenntnisse dieser Arbeit bieten die Entwicklungsgrundlage für das computergestützte Klangdesign von Klimaanlagen und ebnen den Weg für ihre praktische Anwendung., FAU Forschungen, Reihe B, Medizin, Naturwissenschaft, Technik, 27

Istraživanje se bavi problemom individuacije zvuka (sound individuation – SI) i vezom s ontologijom zvuka (sound ontology – SO). Tvrdi se da problemi SI-a, poput aspacijalnosti, ekstremne individuacije, indeksikalne zamršenosti i pazličnosti trajanja postoje zbog nesigurnosti SO-a. Uz to, opisujem gledišta u SO-u, uključujući gledište o valu (wave view – WV), gledište o svojstvu (the property view – PV) i gledište o događaju (event view – EV), kako ih brani Cassey O’Callaghan. Prema O’Callaghanu, EV nudi jasne standarde za individuaciju zvuka. Međutim, tvrdnji se suprotstavlja razmatranje da se standardi mogu braniti bilo kojom pozicijom SO-a, stoga EV ne rješava ni jedan od navedenih problema. Da bi se pokazale poteškoće naslijeđene imanentnom ontologijom zvuka, razmatra se problem jezikoslovnog predstavljanja. Problem SI-a može se razviti unutar okvira filozofije jezika i, napose, u svezi s raspravom o masovnim usuprot brojeće-sortnim terminima. Je li termin zvuk masovna ili brojeće-sortna riječ? Pokazuje se da, zbog razloga pripadajućih SO-u, pitanje ostaje otvoreno. SI je, stoga, pokriveno od SO-a do filozofije jezika., This paper addresses the problem of sound individuation (SI) and its connection to sound ontology (SO). It is argued that the problems of SI, such as aspatiality, extreme individuation, indexical perplexity and duration puzzles are due to SO's uncertainties. Besides, I describe the views in SO, including the wave view (WV), the property view (PV), and the event view (EV), as Cassey O’Callaghan defends it. According to O’Callaghan, EV offers clear standards to individuate sounds. However, this claim is countered by the consideration that any view could also defend the standards in SO, and thus, EV does not solve any of the problems mentioned above. As a way of showing the difficulties inherited by sound’s inner ontology, the problem of its linguistic representation is also addressed. The problem of SI can be developed within the frame of the philosophy of language and, specifically, regarding the discussion about mass vs count-sortal terms. Is the term sound a mass or a count-sortal? It is shown that, for reasons pertaining SO, the decision regarding the case of sound as a mass or count-sortal term remains open. SI is, thus, covered from the SO to the philosophy of language., Cet article traite du problème de l’individualisation du son (sound individuation – SI) et de sa relation avec l’ontologie du son (sound ontology – SO). Il est avancé que les problèmes de SI, tels que l’aspatialité, l’individuation extrême, la perplexité indicielle et les énigmes de durée sont dus aux incertitudes de SO. Par ailleurs, je décris les vues dans SO, y compris la vue d’onde (wave view – WV), la vue de propriété (property view – PV) et la vue d’événement (event view – EV), comme Cassey O’Callaghan les défend. Selon O’Callaghan, EV propose des normes claires pour l’individualisation des sons. Cependant, cette affirmation est contrée par le fait que les normes pourraient également être défendues par n’importe quel vue de SO, de sorte que EV ne résout aucun des problèmes mentionnés. Afin de montrer les difficultés héritées de l’ontologie intérieure du son, le problème de sa représentation linguistique est également abordé. Le problème de SI peut être développé dans le cadre de la philosophie du langage et, en particulier, en ce qui concerne la discussion entre les termes de masse par opposition aux termes compte-sortaux. Le terme son, est-ce une masse ou un compte-sortal ? Il est démontré que, pour des raisons relevant de SO, la question reste ouverte. SI est donc couvert de SO jusqu’à la philosophie du langage., Dieser Aufsatz befasst sich mit dem Problem der Individuation des Klangs (sound individuation – SI) und ihrer Verbindung zur Ontologie des Klangs (sound ontology – SO). Es wird argumentiert, dass die Probleme von SI, wie Aspatialität, extreme Individuation, indexikalische Wirrnis und die Puzzlehaftigkeit des Dauerns auf die Unsicherheiten von SO zurückzuführen sind. Darüber hinaus beschreibe ich Standpunkte in der SO, einschließlich Wellentheorie (wave view – WV), Eigenschaftstheorie (property view – PV) und Ereignistheorie (event view – EV), wie Cassey O’Callaghan sie verteidigt. O’Callaghan zufolge bietet EV klare Maßstäbe für die Individuierung von Klängen. Dieser Begründung ist jedoch die Erwägung entgegengesetzt, die Maßstäbe könnten auch von irgendeiner Ansicht in der SO verteidigt werden, sodass EV keines der oben genannten Probleme löse. Als ein Weg, um die Schwierigkeiten aufzuzeigen, welche von der dem Klang innewohnenden Ontologie geerbt sind, wird auch das Problem seiner sprachlichen Repräsentation angesprochen. Das Problem der SI kann im Rahmen der Sprachphilosophie und insbesondere hinsichtlich der Diskussion über Massen- gg. zähl-sortale Begriffe entwickelt werden. Ist der Begriff Klang ein Massen- oder ein zähl-sortaler Terminus? Es wird gezeigt, dass aus Gründen, die die SO betreffen, die Entscheidung über den Fall von Klang als Massen- bzw. zähl-sortalem Begriff dahingestellt bleibt. SI wird somit von der SO bis zur Sprachphilosophie abgedeckt.

While binaural technology applications gained in popularity in recent years, the majority of applications still use non-individual Head-Related Transfer Functions (HRTFs) from artificial heads. These datasets enable a reasonably good spatial localization which works especially well when using an additional visual cue. However, certain applications, for example research of spatial hearing or hearing attention, require an physically exact and realistic binaural signal. Moreover, it was shown in many experiments that there is a substantial gain from the use of individual HRTFs, for example in localization tasks. The limiting factor that prohibits the widespread use of individual HRTFs is the acquisition of such data. A substantial hardware requirement obstructs a more universal usage. Even for institutions that allow individual measurements, the measurement time that is required, and that the subjects are required to remain motionless made most measurements unfeasible in the past. This time requirement has recently been reduced by the use of parallelization in the measurement signal which lead to the development of fast measurement systems capable of acquiring individual and spatially dense HRTF. This thesis provides a objective and subjective evaluation of such a system that is designed with the goal of little disturbance of the measurements in mind. The construction is detailed, followed by both an objective and subjective evaluation. A detailed investigation into additional distortion of the sound field introduced by the system itself is presented and it is shown that the system performs comparably to a conventional system in terms of sound source localization. Furthermore, a method is introduced and evaluated to further reduce the measurement time by using continuous rotation during the measurement. This method is used to reduced the measurement duration from eight minutes to three minutes without audible differences. The introduced methods are also used to reducing additional errors from subject movement. It is shown that this movement can be reduced by a visual feedback system to a level that can be compensated efficiently.

Im Rahmen des vorliegenden Beitrags wird der Bedarf für die Entwicklung neuer Online-Lehrmedien an der TU Braunschweig erhoben. Anhand der Ergebnisse wird eine Online-Lernplattform auf der Basis eines Wikis entwickelt und in den Fachrichtungen Küsteningenieurwesen und Akustik eingesetzt. Die Lernplattformen enthalten Videos zu Lehrthemen und Laborversuchen, interaktive Diagramme, sowie, im Bereich der Akustik, Soundbeispiele. Die Lernplattformen sind online frei für jedermann zugänglich und können daher sowohl durch die Studierenden in jeder Phase des Studiums, als auch direkt in der Präsenzveranstaltung eingesetzt werden. Dadurch ergibt sich eine durchgängige Nutzung der Lehrmedien, welche nachhaltigen Lernerfolg fördert. (DIPF/Orig.)

Camiler İslam Dininin ibadet mekanları ve çok sayıda insanın bir arada ibadet ettiği binalardır. Bu sebeple iç mekanlarında oluşan sesin, ortam içerisinde dağılımı ile dinleyiciler tarafından optimum şekilde algılanması mimari akustik açısından önem taşımaktadır. Bundan dolayı çalışmada, Trabzon’da yer alan Yavuz Sultan Selim Camii’ne ait akustik özellikler incelenmiş, Bilgisayar Simülasyon Yöntemi ile Sesin Nesnel Parametreleri açısından değerlendirilmiştir. Değerlendirme Çınlama Süresi (RT), Erken Gecikme Süresi (EDT), Belirginlik (D50), Netlik (C80) ve Konuşma İletim Endeksi (STI) nesnel parametreleri ile gerçekleştirilmiştir. Çalışmada; caminin boş, %50 dolu ve %100 dolu olduğu durumlar için, alıcıların oturma ve ayakta durma pozisyonlarında, ses kaynağı olan imamın namaz kıldırdığı ve hutbede vaaz verdiği iki konum dikkate alınmıştır. Simülasyon neticesi elde edilen nesnel parametre değerleri ile caminin akustik performansı tespit edilmiştir. Sonuçlar yorumlanarak sebepleri hakkında fikir yürütülmüştür.

Barn förväntas kunna leka, vila och lära sig på skolgården, men ljudnivåerna är ofta höga. Det ger upphov till frågan om ljudmiljön på skolgårdar ligger på lämpliga nivåer för dessa tre aktiviteter och hur den kan anpassas. Syftet med examensarbetet är att identifiera vad en lämplig ljudmiljö på skolgårdens olika platser är och att identifiera vilka åtgärder och designverktyg som kan användas för att förbättra ljudmiljön. Undersökning av hur och i vilken utsträckning en ljudmiljö kan modifieras för att göra den lämplig för utomhusundervisning utförs också. Examensarbetet avgränsas till grundskolor för barn mellan sex och sexton år och hur skolgården kan anpassas till barn i den åldern. Relevanta studier om hur ljud och ljudmiljö påverkar barns hälsa, inlärnings- och prestationsförmåga undersöktes för att identifiera kriterier för de tre funktionerna: (1) lek, (2) rekreation och (3) pedagogisk verksamhet. Genom att studera både forskning om den akustiska effekten av olika designverktyg och forskning om miljöer för barn identifieras akustiska designverktyg som kan användas för skolgårdar. Slutligen analyserades möjligheten att anpassa olika områden på skolgården för de tre funktionerna genom att modellera i CATT-Acoustic och genom att undersöka ljudmiljön på två befintliga innerstadsskolor som ett ljudlandskap. I CATT-Acoustic användes parametrarna efterklangstid, T20, ljudförstärkning, G, och Speech Transmission Index, STI. Resultatet var att en lämplig ljudmiljö anpassad till (1) lek kan ha en låg taltydlighet (STI mellan 0,46 och 0,66), en begränsad efterklangstid (T20 under 1,2 s) och är öppen med en ljuddämpande markyta, (2) rekreation har en kort efterklangstid T20 under 0,5 s), en begränsad ekvivalent ljudnivå Leq under 50 dBA) och absorberande eller ojämna ytor i sin omgivning och (3) undervisning bör integreras inom skolgården och bestå av platser där undervisning och annan verksamhet kan äga rum. Där föreslås T20 vara 0,5 s, Leq under 50 dBA och absorberande ytor som ger bra förutsättningar för röstkommunikation och lärande. Minst en plats föreslås vara en mötesplats som uppfyller kriterierna för undervisning som förstärker tal genom att ha en reflekterande yta placerad bakom talarens position och vara avskärmad av en absorberande vägg. Undersökningen visade att designen av skolgården och platsen för verksamheten i förhållande till skolgårdsväggarna kan förbättra ljudmiljön. Genom mjuka markmaterial (gräs, sand och grus), indelning av skolgården i flera zoner med exempelvis växtbeklädda barriärer och avskärmning från ljud utanför skolgården, kan ljudmiljön förbättras. Bullriga aktiviteter kan placeras längre bort från reflekterande ytor och ett rekreationsområde kan skapas genom absorberande ytor och diffusa skärmar. Undervisningen kan ske på många olika platser där minst en kan vara nära en reflekterande vägg som förstärker talet. Children are expected to be able to play, rest and have lessons in schoolyards. This made me interested in investigating if the sound environment in schoolyards is at suitable levels for these three activities. The purpose of my master’s thesis was to identify what a suitable sound environment in the different areas of a schoolyard is, and to identify measures and design tools that can be used to improve the sound environment. I also investigate in what extent a sound environment can be modified to make it suitable for outdoor education. The thesis focuses on schools with six- to sixteen-year-old pupils and how children this age are affected by the sound environment. Relevant studies on how sound and the sound environment affect children’s health, learning and performance skills were examined to identify criteria for the three functions: (1) play, (2) recreation and (3) educational activities. By studying research about design tools and their acoustic effect on the one hand and studies about environments for children on the other hand I identified acoustic design tools which could be used in schoolyards. At last I analysed the possibility to adjust different areas for the three functions. I analysed the sound environment on two inner city schools as a “soundscape” and modelled sound distribution in an open space similar to inner-city schoolyards in CATT-Acoustic and used the parameters reverberance time (RT), gain (G) and Speech Transmission Index (STI). As result of this master’s thesis an appropriate sound environment in an area for (1) play has a lower speech understanding (STI between 0.46 and 0.66), has a limited reverberation time (RT under 1,2 s) and open with a sound-damping ground surface (2) recreation has a short reverbaration time (RT under 0.5 s), limited equivalent noise level (Leq under 50 dBA) and a lot of absorbent or diffuse surfaces in its surroundings (3) teaching should be integrated in the schoolyard as places where teaching and other activities can take place. There you should find 0.5 s RT, under 50 dBA Leq and absorbent surfaces that provide good conditions for voice communication and learning. At least one place is proposed to be a meeting place that meets the criteria for teaching and amplifies speech by having a reflective surface placed behind the speaker position and shielded by some absorbent wall. It is found that the design of the schoolyard and the location of the activities in relation to the schoolyard walls can improve the sound environment. The sound environment can be improved through especially soft ground materials (grass, sand and gravel), subdivision of the schoolyard into smaller areas, while using sound absorbing noise barriers which can be combined with planting and protect from noise from outside the schoolyard. Noisy activities can be placed further away from reflective areas and an area for recreation can be created through absorbent surfaces and diffuse screens. Teaching can take place in many different places where at least one of the places can be close to one reflective wall that amplifies the speech.

PTB-Mitteilungen. Band 129 (2019), Heft 3. ISSN 0030-834X, Der Deutsche Kalibrierdienst (DKD): Eine Erfolgsgeschichte geht weiter - Peter Ulbig - 03 Die Fachausschüsse im Deutschen Kalibrierdienst - 09 40 Jahre Deutscher Kalibrierdienst - 15 Begrüßung - Joachim Ullrich - 17 Grußwort - Ole Janssen - 19 Alle Macht den Konstanten - Jens Simon, Imke Frischmuth - 23 Aufbruch in das Kalibrierwesen der Zukunft – von der Forschung in die Praxis - Peter Ulbig - 27 Zusammenarbeit PTB und DAkkS – Erfolgsgarantie für das deutsche Kalibrierwesen - Stephan Finke - 31 Der Beitrag der Kalibration zur digitalen Produktion - Ulrich Kaiser - 37 Grußwort der Deutschen Gesellschaft für Qualität (DGQ) - Beate Kulessa - 41 Die Entwicklung von der Bestätigung als erstes DKD-Kalibrierlabor zur heutigen DAkkS-Akkreditierung - Lioba Stenner - 43 24 Jahre Zusammenarbeit und Wünsche für die Zukunft - Lars Ahrendt - 49 Internationale Spitzenleistungen sind kein Zufall – SPEKTRA sagt Danke - Holger Nicklich - 51 Kalibrieren von Strommessgeräten für DC-Ströme bis 2000 A - Marcus Escher - 54 Referenzsysteme für Messgrößen in der Laboratoriumsmedizin - Gerhard Schumann - 57 Impressionen - 64

Str��mungsakustische Voruntersuchungen in der hart umk��mpften Automobilindustrie erfordern schnelle numerische Simulationsmethoden, um einen ersten Einblick in die Str��mung und das akustische Feld zu erhalten. Auch wenn es M��glichkeiten gibt, praktisch alle Turbulenzl��ngenskalen aufzul��sen, sind diese Verfahren in fr��hen Phasen der Automobilkomponentenentwicklung nicht zweckm����ig. Deshalb konzentriert sich die vorliegende Arbeit auf einen stochastischen Ansatz zur Rekonstruktion der turbulenten Geschwindigkeitsschwankungen, die auf einer zeitsparenden station��ren Str��mungsl��sung basieren. Als praktische ingenieurtechnische Anwendung wurde eine Kavit��t mit einer ��berh��ngenden Lippe betrachtet, f��r die Messungen und Simulationsergebnisse aus der Literatur vorliegen. Die gesamte Arbeit basiert auf dem hybriden Workflow der Aeroakustik, der im Wesentlichen aus drei Schritten besteht: 1. Durchf��hren einer Str��mungsberechnung; 2. Berechnen von akustischen Quelltermen; 3. Simulieren der akustischen Wellenausbreitung. Zus��tzlich wurde die stochastische Rekonstruktion des turbulenten Geschwindigkeitsfeldes nach Schritt eins eingef��gt. Jeder dieser Schritte wurde im Hinblick auf die betrachtete Kavit��t der vorliegenden Arbeit ausf��hrlich beschrieben. Nach der Betrachtung der notwendigen inkompressiblen Str��mungsrechnung wurde besonderes Augenmerk auf die Rekonstruktion des turbulenten Geschwindigkeitsfeldes gelegt. Dabei wurde der Algorithmus unter Verwendung von Pseudocode beschrieben. In einem n��chsten Schritt wurde die Berechnung von akustischen Quelltermen diskutiert. Ein entscheidender Punkt im hybriden str��mungsakustischen Workflow ist die Interpolation der Quellterme von dem Akustiknetz auf das Str��mungsnetz. Dazu wurden zwei anspruchsvolle Interpolationsverfahren hinsichtlich ihrer F��higkeiten im hybriden aeroakustischen Workflow analysiert. Schlie��lich wurden die resultierenden akustischen Spektren mit Messungen und Simulationsergebnissen verglichen. Dabei waren die in dieser Arbeit erzielten Ergebnisse in guter ��bereinstimmung. Dies hat das Potential der stochastischen Methoden f��r praktische aeroakustische Probleme gezeigt, wie zum Beispiel die Str��mung ��ber eine Kavit��t, die in dieser Arbeit analysiert wurde., Preliminary aeroacoustic studies in the highly competitive automotive industry require fast numerical simulation methods to gain a first insight in the flow and the acoustic field. Even though there are possibilities to resolve virtually all turbulence length scales, these procedures are infeasible in early stages of automotive component development. Therefore, the present thesis focuses on a stochastic approach to reconstruct the turbulent velocity fluctuations based on a very time efficient steady flow solution. As a practical engineering application, a cavity with an overhanging lip was considered, where measurements and simulation results are available from the literature. The entire work is based on the hybrid workflow for aeroacoustic simulations, which basically consists of three steps: 1. perform a flow computation; 2. compute acoustic source terms; 3. simulate the acoustic wave propagation. Additionally, the stochastic reconstruction of the turbulent velocity field was inserted after step one. Each of these steps was described in detail with regard to the considered cavity in the present thesis. After discussing the necessary incompressible flow computation, special emphasis was given to the reconstruction of the turbulent velocity field. Thereby, the algorithm was outlined utilizing pseudo code. In a next step, the calculation of acoustic source terms was discussed. A crucial point in the hybrid aeroacoustic workflow is the interpolation of the source terms on the flow grid to the acoustic grid. Therefore, two highly sophisticated interpolation procedures were analyzed towards their capabilities in the hybrid aeroacoustic workflow. Eventually, the resulting acoustic spectra were compared with measurements and simulation results. Thereby, the results obtained in this thesis were in good agreement. This has shown the potential of stochastic methods for practical aeroacoustic engineering problems, such as the flow over a cavity that was analyzed in this work.

Perforierte Wandauskleidungen mit Kavität, auch Liner genannt, stellen eine wichtige Schallreduktionstechnologie in durchströmten Kanälen wie beispielsweise Flugzeugtriebwerken dar. Bei modernen, emissionsarmen Triebwerken sind die zu dämpfenden Frequenzbestandteile eher tieffrequent und breitbandig auf einen größeren Frequenzbereich verteilt. Hierfür benötigen konventionelle, auf dem Resonatorprinzip basierende Linerkonzepte einen deutlich größeren Bauraum, der in Triebwerken zumeist nicht verfügbar ist. Daher besteht Bedarf an neuartigen Systemen mit breitbandiger Dämpfung. Vor diesem Hintergrund wird in dieser Arbeit das Wirkungsprinzip des sogenannten Zero-MassFlow-Liners (ZML) genauer untersucht. Das Dissipationsverhalten wird durch eine periodische Durchströmung der perforierten Wand erweitert. Für die zusätzliche Dissipation werden Wirbelbildung und -ablösung an den Löchern der perforierten Wand, ähnlich wie bei konstant durchströmten, sogenannten Bias-Flow-Linern (BFL), verantwortlich gemacht. Der Vorteil dieses Konzeptes ist, dass gegenüber dem BFL keine zusätzliche Luftversorgung benötigt wird. Im Labor kann eine periodische Durchströmung beispielsweise mit einem Lautsprecher hergestellt werden. In dieser Studie wird das Dissipationsverhalten periodisch durchströmter Liner in Abhängigkeit von der Schallschnelle in den Löchern und der Anregungsfrequenz untersucht. Die Ergebnisse zeigen für verschiedene Wandauskleidungen, dass das Dissipationsverhalten mit steigender Schallschnelle einen breitbandigeren Verlauf annimmt und die Anregungsfrequenz einen vergleichsweise geringen Einfluss hat.