Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 38 for “"Acoustic performance"”.
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Acoustic performance of bias flow liners in gas turbine combustors
Der Einsatz moderner Verbrennungskonzepte zur Effizienzsteigerung und Schadstoffreduktion bei Gasturbinen wird oft durch thermo-akustische Instabilitäten verhindert. Durchströmte Brennkammerliner können die akustische Dämpfung des Systems erhöhen und die Instabilitäten unterdrücken. Eine …
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Representative Environments for Reduced Estimation Time of Wide Area Acoustic Performance
… and forecasts (predicted ocean fields) of acoustic propagation conditions in the ocean which can greatly improve the planning of acoustic experiments. Modeling of acoustic transmission loss (TL) provides information about how the environment impacts acoustic performance for various systems …
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Structural elements with mathematically defined surfaces for enhanced structural and acoustic performance
… explored to reduce vibration, minimize unwanted acoustic noise, and increase stiffness in structures. The first design approach is to create nearly isotropic panels with increased stiffness using two-dimensional curvature. These quasi-isotropic designs can be used in lieu of typical panel …
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Evaluation of the Aerodynamic and Acoustic Performance of a Novel Passive Bat Deterrent for Wind Energy Applications
… decreasing energy production and active acoustic bat deterrents constrained by atmospheric attenuation, preventing full coverage of the rotor swept area. Passive ultrasonic deterrents integrated along the length of turbine blades offer a potential alternative, but their aerodynamic impact …
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Acoustic and non-acoustic performance of coal bottom ash as sound absorptive material for reducing railway noise level
… led to various types of pollution, especially acoustic pollution in urban areas. Furthermore, the huge production of Coal Bottom Ash (CBA) is treated as waste and often placed into impoundment ponds, silos or landfills, which has contributed to environmental issues. Usage of CBA in concrete …
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Investigation of the Aerodynamic and Acoustic Performance of a Scaled eVTOL Propeller in Axial and Non-Axial Flight
… in the understanding of their aerodynamic and acoustic performance, particularly when interacting with disturbances such as turbulence generated by buildings. To address safety, noise, and performance challenges, effective optimization methods must be developed. However, there is a lack of …
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Effect of struts on aeroacoustics of axisymmetric supersonic inlets
… effect of strut position on the aerodynamic and acoustic performance of a supersonic inlet. The investigated inlet was a prototype 1/14 scale model of a mixed compression, axisymmetric supersonic inlet designed for the high speed civil transport aircraft. A 10.4 cm (4.1 in.) turbofan engine …
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Simultaneous structural/acoustical design of composite panels
… of airborne noise thereby requiring heavier acoustical treatments. A sequential design approach of addressing first structural and then acoustical design does not take advantage of structural/acoustical coupling. A simultaneous approach is expected to help minimize the total sidewall mass. …
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Vibrations in Lightweight Buildings - Perception and Prediction
… tools for the verification of vibratory and acoustic performance before a building is actually put up. The appended publications Paper A and Paper B, aimed at supplementing the lack of existing studies addressing human response to floor vibrations. In order to obtain a better estimate of an …
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Sound Radiation Responses and Acoustic Behvior of Sandwich Panel
… construction engineering. Investigations on the acoustic behavior of sandwich structures is of practical importance, not only for engineers but to researchers in the field. A numerical study of the vibro-acoustic and sound transmission loss (STL) of an aluminum honeycomb core sandwich panel with …
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Classroom Acoustics in the Postsecondary Environment: A Case for Universal Design
… of all ages. This researched aims to assess the acoustic conditions of classrooms in the postsecondary environment and to ascertain why these rooms lack in proper design. College students are not required by law or policy to disclose a disability to their institution of higher education. This can …
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Aeroacoustics of the bifurcated 2D supersonic inlet
… was performed to determine the aerodynamic and acoustic performance of the bifurcated 2D supersonic inlet during takeoff and approach flight conditions, and to compare these results indirectly to those of the axisymmetric supersonic inlet. The comparison is not direct since the centerbody …
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A SEMI-OPEN SOUND ENVELOPE : ENCLOSING SOUNDS WITHIN, REDUCING SOUNDS TRANSMITTED BEYOND
The thesis seeks to address the acoustic performance of naturally ventilated spaces. The focus of research is in the design of a prototype that achieves a desired sound effect in a semi-opened space which is to create an even sound distribution within and a reduced noise transmission beyond the …
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Road traffic noise barrier design : measurements and models concerning multiple-walls and augmented earth mounds
… method which would be of use particularly to non-acousticians. This method indicated that acoustic information available for the design of earth mounds was limited, although this barrier type is commonly used in practice and is known to have a number of non-acoustic benefits. Initial …
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Einfluss des Umrichterbetriebs auf das akustische Verhalten im Gesamtsystem Asynchronmotor-Getriebe
… customer expectation with respect to the noise performance of consumer products creates high customer expectation concerning the noise performance of products used in industrial or publicly accessible installations or machines. With expectations increasing engineers are forced to face the …
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Active Micro-/Nano-Structures for Electromechanical Actuation
… and systems in pursuit of unprecedented device performance and unique system functionality. In particular, cooperative actuation of active structures assembled in parallel results in emerging concepts of electromechanical devices and systems with tunable characteristics enabled by exploiting all …
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Safety First, Bubbles Second: Integrating Regulatory Compliance with Innovation in Rapid Prototyped Focused Ultrasound Devices
… such as histotripsy, introduce safety and performance considerations that may arise during early stages of prototyping. This thesis presents an evaluation framework intended to support early-stage identification of factors related to clinical and regulatory requirements. The framework was …
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Aluminum nitride microelectromechanical infrared detectors with integrated metamaterial absorbers
… (FWHM) of 1.02 μm without compromising resonator acoustic performance. A novel detector readout has also been implemented to boost sensitivity as well as to linearly convert incident IR power to a DC voltage for optimum integration into focal plane arrays (FPAs). A sensitivity metric called the …
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