An array of small, lightweight acoustic sources was investigated to determine how such an arrangement of sources would acoustically interact with a duct similar to that of a turbofan engine inlet. The sources were cylindrically curved aluminum panels excited in vibration by the application of a sinusoidally varying voltage to a piezoceramic actuator bonded to them. The finite element method was used as a design tool to size the panel based on desired vibration characteristics. A boundary element acoustic analysis was used to predict the acoustic output from various arrangements of sources. The central portion of the research was a series of experiments using an array of twelve sources arranged circumferentially in a duct. Measurements of the performance of each source revealed that the performance of the acoustic sources varied from source to source. This variation was assumed to have been caused by differences in the quality of the bond of each of the piezoceramic actuators to the panels. Directivity measurements were made in the far field. Measurements were also taken of the pressure field established in the duct cross-section. Modal decomposition was applied to the data. It was found that the dominant acoustic modes in the duct are those whose cut-on frequencies were near the frequency of excitation. / Master of Science

Turbulent boundary layer and metamaterial properties were explored to initiate the viability of controlling acoustic waves driven by pressure fluctuations from flow. A turbulent boundary layer scaling analysis was performed on zero-pressure-gradient turbulent boundary layers over rough surfaces, for 30,000≤〖Re〗_θ≤100,000. Relationships between fluctuating pressures and velocities were explored through the pressure Poisson equation. Certain scaling laws were implemented in attempts to collapse velocity spectra and turbulence profiles. Such analyses were performed to justify a proper scaling of the low-frequency region of the wall-pressure spectrum. Such frequencies are commonly associated with eddies containing the largest length scales. This study compared three scaling methods proposed in literature: The low-frequency classical scaling (velocity scale U_τ, length scale δ), the convection velocity scaling (U_e-U ̅_c, δ), and the Zagarola-Smits scaling (U_e-U ̅, δ). A default scaling (U_e, δ) was also selected as a baseline case for comparison. At some level, the classical scaling best collapsed rough and smooth wall Reynolds stress profiles. Low-pass filtering of the scaled turbulence profiles improved the rough-wall scaling of the Zagarola-Smits and convection velocity laws. However, inconsistent scaled results between the pressure and velocity requires a more rigorous pressure Poisson analysis. The selection of a proper scaling law gives insight into turbulent boundary layers as possible sources for acoustic metamaterials. A quiescent (no flow) experiment was conducted to measure the capabilities of a metamaterial in retaining acoustic surface waves. A point source speaker provided an acoustic input while the resulting sound waves were measured with a probe microphone. Acoustic surface waves were found via Fourier analysis in time and space. Standing acoustic surface waves were identified. Membrane response properties were measured to obtain source condition characteristics for turbulent boundary layers once the metamaterial is exposed to flow. / Master of Science / Aerodynamicists are often concerned with interactions between fluids and solids, such as an aircraft wing gliding through air. Due to frictional effects, the relative velocity of the air on the solid-surface is negligible. This results in a layer of slower moving fluid near the surface referred to as a boundary layer. Boundary layers regularly occur in the fluid-solid interface, and account for a sufficient amount of noise and drag on aircraft. To compensate for increases in drag, engines are required to produce increased amounts of power. This leads to higher fuel consumption and increased costs. Additionally, most boundary layers in nature are turbulent, or chaotic. Therefore, it is difficult to predict the exact paths of air molecules as they travel within a boundary layer. Because of its intriguing physics and impacts on economic costs, turbulent boundary layers have been a popular research topic. This study analyzed air pressure and velocity measurements of turbulent boundary layers. Relationships between the two were drawn, which fostered a discussion of future works in the field. Mainly, the simultaneous measurements of pressure on the surface and boundary layer velocity can be performed with understanding of the Pressure Poisson equation. This equation is a mathematical representation of the boundary layer pressure on the surface. This study also explored the possibility of turbulent-boundary-layer-driven-acoustic-metamaterials. Acoustic metamaterials contain hundreds of cavities which can collectively manipulate passing sound waves. A facility was developed at Virginia Tech to measure this effect, with aid from a similar laboratory at Exeter University. Microphone measurements showed the reduction of sound wave speed across the metamaterial, showing promise in acoustic manipulation. Applications in metamaterials in the altering of sound caused by turbulent boundary layers were also explored and discussed.

The monitoring of harmful ambient vapors is of major concern in the industrial environment. To this end, the development of systems which detect and respond in real time to specific vapors is a highly desirable goal. Surface Acoustic Wave (SAW) devices have been used for chemical analysis since 1978. While sensitive to mass changes occurring on their surfaces, they are not selective to the mass they will detect. Their use as chemical sensors requires the development of specificity for a vapor (or class of vapors) using selective chemical reagents suspended in film media that can have their permeability easily changed. This dissertation presents the development of an automated dosimeter for the detection of phosgene using SAW devices. By changing the film media from a very permeable material to a film exhibiting less permeability, the analytical range of the device using the same suspended selective chemical reagent is expanded to concentrations which the very permeable film is incapable of accurately measuring. / Ph. D.

In this study, ambient noise wavefield was used for the first time to image spatial and temporal upper crustal seismic structures in NW-Bohemia/Vogtland region. The data come from 111 stations and were collected from continuous recordings of the permanent station networks of Germany and Czech Academy of Sciences as well as temporary stations of the BOHEMA and PASSEQ experiments. Rayleigh and Love waves travelling between each station-pair are extracted by cross-correlating long time series of ambient noise data recorded at the stations. Group velocity dispersion curves are obtained by time-frequency analysis of cross-correlation functions between 0.1 and 1 Hz, and are tomographically inverted to provide 2-D group velocity maps. At shorter periods Rayleigh wave group velocity maps are in good agreement with surface geology where low velocity anomalies appear along Mariánské Lázně Fault and Eger rift. A low velocity zone is observed at the northern edge of Mariánské Lázně Fault which shifts slightly to the south with increasing period and correlates well with the main focal zone of the earthquake swarms at 5 s period. We invert the 2-D group velocity maps into a 3-D shear wave velocity model. In this step Love waves were excluded from further analysis because of their high level of misfit to modelled dispersion curves. Horizontal and vertical sections through the model reveal a clear low velocity zone above the Nový Kostel seismic focal zone which narrows towards the top of the seismic activity and ends above the shallowest hypocenters at 7 km depth. We investigate temporal variation of seismic velocity within and around the Nový Kostel associated with 2008 and 2011 earthquake swarms by employing Passive Image Interferometry method using 7 continuous seismograms recorded by the WEBNET network. The results reveals stable seismic velocities without a clear post seismic velocity change during earthquake swarms in the Nový Kostel area.

Bulk rock strength is greatly dependent on fracture density, so that reductions in rock strength associated with faulting and fracturing should be reflected by reduced shear coupling and hence S-wave velocity. This study is carried out along the Canterbury rangefront and in Otago. Both lie within the broader plate boundary deformation zone in the South Island of New Zealand. Therefore built structures are often, , located in areas where there are undetected or poorly defined faults with associated rock strength reduction. Where structures are sited near to, or across, such faults or fault-zones, they may sustain both shaking and ground deformation damage during an earthquake. Within this zone, management of seismic hazards needs to be based on accurate identification of the potential fault damage zone including the likely width of off-plane deformation. Lateral S-wave velocity variability provides one method of imaging and locating damage zones and off-plane deformation. This research demonstrates the utility of Multi-Channel Analysis of Surface Waves (MASW) to aid land-use planning in such fault-prone settings. Fundamentally, MASW uses surface wave dispersive characteristics to model a near surface profile of S-wave velocity variability as a proxy for bulk rock strength. The technique can aid fault-zone planning not only by locating and defining the extent of fault-zones, but also by defining within-zone variability that is readily correlated with measurable rock properties applicable to both foundation design and the distribution of surface deformation. The calibration sites presented here have well defined field relationships and known fault-zone exposure close to potential MASW survey sites. They were selected to represent a range of progressively softer lithologies from intact and fractured Torlesse Group basement hard rock (Dalethorpe) through softer Tertiary cover sediments (Boby’s Creek) and Quaternary gravels. This facilitated initial calibration of fracture intensity at a high-velocity-contrast site followed by exploration of the limits of shear zone resolution at lower velocity contrasts. Site models were constructed in AutoCAD in order to demonstrate spatial correlations between S-wave velocity and fault zone features. Site geology was incorporated in the models, along with geomorphology, river profiles, scanline locations and crosshole velocity measurement locations. Spatial data were recorded using a total-station survey. The interpreted MASW survey results are presented as two dimensional snapshot cross-sections of the three dimensional calibration-site models. These show strong correlations between MASW survey velocities and site geology, geomorphology, fluvial profiles and geotechnical parameters and observations. Correlations are particularly pronounced where high velocity contrasts exist, whilst weaker correlations are demonstrated in softer lithologies. Geomorphic correlations suggest that off-plane deformation can be imaged and interpreted in the presence of suitable topographic survey data. A promising new approach to in situ and laboratory soft-rock material and mass characterisation is also presented using a Ramset nail gun. Geotechnical investigations typically involve outcrop and laboratory scale determination of rock mass and material properties such as fracture density and unconfined compressive strength (UCS). This multi-scale approach is espoused by this study, with geotechnical and S-wave velocity data presented at multiple scales, from survey scale sonic velocity measurements, through outcrop scale scanline and crosshole sonic velocity measurements to laboratory scale property determination and sonic velocity measurements. S-wave velocities invariably increased with decreasing scale. These scaling relationships and strategies for dealing with them are investigated and presented. Finally, the MASW technique is applied to a concealed fault on the Taieri Ridge in Macraes Flat, Central Otago. Here, high velocity Otago Schist is faulted against low velocity sheared Tertiary and Quaternary sediments. This site highlights the structural sensitivity of the technique by apparently constraining the location of the principal fault, which had been ambiguous after standard processing of the seismic reflection data. Processing of the Taieri Ridge dataset has further led to the proposal of a novel surface wave imaging technique termed Swept Frequency Imaging (SFI). This inchoate technique apparently images the detailed structure of the fault-zone, and is in agreement with the conventionally-determined fault location and an existing partial trench. Overall, the results are promising and are expected to be supported by further trenching in the near future.

L'objectif de cette thèse est de construire un modèle d'atténuation sismique du manteau supérieur dela Terre en utilisant un jeu de données original construit par Debayle et Ricard (2012). Ce jeu dedonnées est l'un des plus complet au monde (plus de 375 000 sismogrammes analysés pour extrairel'atténuation et la vitesse de phase du mode fondamental et des cinq premiers harmoniques des ondesde Rayleigh).Les mesures d'atténuation sont tout d'abord traitées pour extraire les effets de l'expansion géométriqueet de la focalisation, minimiser les effets d'erreurs sur la source, écarter les mesures incertaines etregrouper les mesures redondantes. Elles sont ensuite régionalisées pour obtenir des cartes desvariations latérales de l'atténuation des ondes de Rayleigh pour chaque mode et chaque période. Ladernière étape est l'inversion en profondeur des cartes. Elle permet d'obtenir QsADR17, un modèle 3Dde l'atténuation des ondes S dans le manteau supérieur.QsADR17 est corrélé avec la tectonique de surface jusqu'à 200 km de profondeur, avec une faibleatténuation sous les continents et une forte atténuation sous les océans. Des anomalies de forteatténuation sont observées jusqu'à 150~km de profondeur sous les rides océaniques, et persistent à plusgrande profondeur jusque dans la zone de transition sous la plupart des points chauds. La présence delarges anomalies atténuantes situées à 150 km de profondeur sous l'océan Pacifique suggère queplusieurs panaches thermiques viennent s'étaler dans l'asthénosphère. Nous avons également détecté laprésence d'hétérogénéités de composition à la base des cratons et dans un certain nombre de régionsactives. / The aim of this study is to build a 3-D attenuation model of Earth's upper-mantle using a unique datasetbuilt by Debayle & Ricard (2012). This dataset is among the largest in the world: more than 375,000seismograms were analyzed to extract Rayleigh-wave attenuation and velocity measurements for thefondamental mode and the five first harmonics between 40 and 240 s periods.First, attenuation measurements are processed to extract the effects of geometrical attenuation and offocusing and defocusing, in order to minimize the influence of errors on the seismic source, to avoidpotentially incorrect data, and to cluster redondant measurements. Then, measurements are regionalizedto obtain Rayleigh-wave maps for each mode and each period. The last step is the inversion of thesemaps to obtain the depth dependent attenuation. Eventually, we obtain QsADR17, a 3-D model of Swaveattenuation in the upper mantle.QsADR17 is correlated with surface tectonics down to 200 km depth, with low attenuation under thecontinents and high attenuation under the oceans. High-attenuation anomalies are found under oceanicridges down to 150~km depth, and under most of the hotspots at larger depth down to the transitionzone. A large high-attenuation anomaly at 150~km depth under the Pacific ocean suggest that thermalplumes pound into the asthenosphere. We also detect compositional heterogeneities at the base of thecratons and in active areas.

Concrete structures can often be modeled as plates, for example, bridges, tunnel walls and pipes. Near-surface damage in concrete structures mostly takes the form of cracking. Surface-breaking cracks affect concrete properties and structural integrity; therefore, the nondestructive evaluation of crack depth is important for structural monitoring, strengthening and rehabilitation. On the other hand, material damping is a fundamental parameter for the dynamic analysis of material specimens and structures. Monitoring damping changes is useful for the assessment of material conditions and structural deterioration. The main objective of this research is to develop new methodologies for depth evaluation of surface-breaking cracks and the evaluation of damping in concrete plates. Nondestructive techniques based on wave propagation are useful because they are non-intrusive, efficient and cost effective. Previous studies for the depth evaluation of surface-breaking cracks in concrete have used diffracted compressional waves (P-waves). However, surface waves exhibit better properties for the characterization of near surface defects, because (a) surface waves dominate the surface response, they carry 67% of the wave propagation energy, and present lower geometrical attenuation because the propagating wave front is cylindrical; and (b) the penetration depth of Rayleigh waves (R-waves) depends on their frequency. Most of the R-wave energy concentrates at a depth of one-third of their wavelengths. The transmission of R-waves through a surface-breaking crack depends on the crack depth; this depth sensitivity is the basis for the so-called Fourier transmission coefficient (FTC) method. R-waves only exist in a half-space (one traction-free surface); whereas in the case of a plate (two traction-free surfaces), Lamb modes are generated. Fundamental Lamb modes behave like R-waves at high frequencies, because their wavelengths are small relative to the plate thickness. Lamb modes are not considered in the standard FTC method, and the FTC method is also affected by the selected spacing between receivers. The FTC calculation requires the use of an explicit time window for the identification of the arrival of surface waves, and the selection of a reliable frequency range. This research presents theoretical, numerical and experimental results. Theoretical aspects of Lamb modes are discussed, and a theoretical transfer function is derived, which can be used to study changes of Lamb modes in the time and frequency domains as a function of distance. The maximum amplitude of the wavelet transform varies with distance because of the dispersion of Lamb modes and the participation of higher Lamb modes in the response. Numerical simulations are conducted to study the wave propagation of Lamb modes through a surface-breaking crack with different depths. The surface response is found to be dominated by the fundamental Lamb mode. Using the 2D Fourier transform, the incident, transmitted and reflected fundamental Lamb modes are extracted. A transmission ratio between the transmitted and incident modes is calculated, which is sensitive to crack depths (d) normalized to the wavelength (λ) in a range (d / λ) = 0.1 to 1/3. A new wavelet transmission coefficient (WTC) method for the depth evaluation of surface-breaking cracks in concrete is proposed to overcome the main limitations of the FTC method. The WTC method gives a global coefficient that is correlated with the crack depth, which does not require time windowing and the pre-selection of a frequency bandwidth. To reduce the effects of wave reflections, which are present in the FTC method because of the non-equal spacing configuration, a new equal spacing configuration is used in the WTC method. The effects of Lamb mode dispersion are also reduced. In laboratory tests, an ultrasonic transmitter with central frequency at 50kHz is used as a source; the 50kHz frequency is appropriate for the concrete plate tested (thickness 80mm), because the fundamental Lamb modes have converged to the Rayleigh wave mode. The new method has also been used in-situ at Hanson Pipe and Precast Inc., Cambridge, Ontario, Canada, and it shows potential for practical applications. In general, the evaluation of material damping is more difficult than the measurement of wave velocity; the dynamic response and attenuation of structural vibrations are predominantly controlled by damping, and the damping is typically evaluated using the modal analysis technique, which requires considerable efforts. The existing methods based on surface waves, use the Fourier transform to measure material damping; however, an explicit time window is required for the spectral ratio method to extract the arrival of surface wave; in addition, a slope of the spectral ratio varies for different frequency ranges, and thus a reliable frequency range needs to be determined. This research uses the wavelet transform to measure material damping in plates, where neither an explicit time window nor the pre-selection of a frequency bandwidth are required. The measured material damping represents an average damping for a frequency range determined by source. Both numerical and experimental results show good agreement and the potential for practical applications.

Concrete structures can often be modeled as plates, for example, bridges, tunnel walls and pipes. Near-surface damage in concrete structures mostly takes the form of cracking. Surface-breaking cracks affect concrete properties and structural integrity; therefore, the nondestructive evaluation of crack depth is important for structural monitoring, strengthening and rehabilitation. On the other hand, material damping is a fundamental parameter for the dynamic analysis of material specimens and structures. Monitoring damping changes is useful for the assessment of material conditions and structural deterioration. The main objective of this research is to develop new methodologies for depth evaluation of surface-breaking cracks and the evaluation of damping in concrete plates. Nondestructive techniques based on wave propagation are useful because they are non-intrusive, efficient and cost effective. Previous studies for the depth evaluation of surface-breaking cracks in concrete have used diffracted compressional waves (P-waves). However, surface waves exhibit better properties for the characterization of near surface defects, because (a) surface waves dominate the surface response, they carry 67% of the wave propagation energy, and present lower geometrical attenuation because the propagating wave front is cylindrical; and (b) the penetration depth of Rayleigh waves (R-waves) depends on their frequency. Most of the R-wave energy concentrates at a depth of one-third of their wavelengths. The transmission of R-waves through a surface-breaking crack depends on the crack depth; this depth sensitivity is the basis for the so-called Fourier transmission coefficient (FTC) method. R-waves only exist in a half-space (one traction-free surface); whereas in the case of a plate (two traction-free surfaces), Lamb modes are generated. Fundamental Lamb modes behave like R-waves at high frequencies, because their wavelengths are small relative to the plate thickness. Lamb modes are not considered in the standard FTC method, and the FTC method is also affected by the selected spacing between receivers. The FTC calculation requires the use of an explicit time window for the identification of the arrival of surface waves, and the selection of a reliable frequency range. This research presents theoretical, numerical and experimental results. Theoretical aspects of Lamb modes are discussed, and a theoretical transfer function is derived, which can be used to study changes of Lamb modes in the time and frequency domains as a function of distance. The maximum amplitude of the wavelet transform varies with distance because of the dispersion of Lamb modes and the participation of higher Lamb modes in the response. Numerical simulations are conducted to study the wave propagation of Lamb modes through a surface-breaking crack with different depths. The surface response is found to be dominated by the fundamental Lamb mode. Using the 2D Fourier transform, the incident, transmitted and reflected fundamental Lamb modes are extracted. A transmission ratio between the transmitted and incident modes is calculated, which is sensitive to crack depths (d) normalized to the wavelength (λ) in a range (d / λ) = 0.1 to 1/3. A new wavelet transmission coefficient (WTC) method for the depth evaluation of surface-breaking cracks in concrete is proposed to overcome the main limitations of the FTC method. The WTC method gives a global coefficient that is correlated with the crack depth, which does not require time windowing and the pre-selection of a frequency bandwidth. To reduce the effects of wave reflections, which are present in the FTC method because of the non-equal spacing configuration, a new equal spacing configuration is used in the WTC method. The effects of Lamb mode dispersion are also reduced. In laboratory tests, an ultrasonic transmitter with central frequency at 50kHz is used as a source; the 50kHz frequency is appropriate for the concrete plate tested (thickness 80mm), because the fundamental Lamb modes have converged to the Rayleigh wave mode. The new method has also been used in-situ at Hanson Pipe and Precast Inc., Cambridge, Ontario, Canada, and it shows potential for practical applications. In general, the evaluation of material damping is more difficult than the measurement of wave velocity; the dynamic response and attenuation of structural vibrations are predominantly controlled by damping, and the damping is typically evaluated using the modal analysis technique, which requires considerable efforts. The existing methods based on surface waves, use the Fourier transform to measure material damping; however, an explicit time window is required for the spectral ratio method to extract the arrival of surface wave; in addition, a slope of the spectral ratio varies for different frequency ranges, and thus a reliable frequency range needs to be determined. This research uses the wavelet transform to measure material damping in plates, where neither an explicit time window nor the pre-selection of a frequency bandwidth are required. The measured material damping represents an average damping for a frequency range determined by source. Both numerical and experimental results show good agreement and the potential for practical applications.

Micromachined gyroscopes are attractive replacements to conventional macro-mechanical and optical gyroscopes due to their small size, low power and low cost. The application domain of these devices is quickly expanding from automotive to aerospace and consumer electronics industries. As potential high volume consumer applications for micromachined gyroscopes continue to emerge, design and manufacturing techniques that improve their performance, shock survivability and reliability without driving up the cost and size become important. Today, state-of-the-art micromachined gyroscopes can achieve high performance with low frequency operation (3-30kHz) but at the cost of large form factor, large operating voltages and high vacuum packaging. At the same time, most consumer applications require gyroscopes with fast response time and high shock survivability, which are generally unavailable in low frequency gyroscopes. As a result, innovative designs and fabrication technologies that will offer more practical gyroscopes are desired. In this dissertation, capacitive bulk acoustic wave (BAW) silicon disk gyroscopes are introduced as a new class of micromachined gyroscope to investigate the operation of Coriolis-based vibratory gyroscopes at high frequency and further meet consumer electronics market demands. Capacitive BAW gyroscopes, operating in the frequency range of 1-10MHz are stationary devices with vibration amplitudes less than 20nm, resulting in high device bandwidth and high shock tolerance. They require low operating voltages, which simplifies the interface circuit design and implementation in standard CMOS technologies. They also demonstrate appropriate thermally stable performance in air, which eliminates the need both for vacuum packaging and for temperature control. A revised high aspect ratio poly- and single crystal silicon (HARPSS) process was utilized to implement these devices in thick SOI substrates with very small capacitive gap sizes (~200 nm). The prototype devices show ultra-high quality factors (Q>200,000) and large bandwidth of 15-30Hz. In addition, the design and implementation of BAW disk gyroscopes are optimized for self-matched mode operation. Operating a vibratory gyroscope in matched mode is a straightforward way to improve performance parameters but, is challenging to achieve without applying large voltages. In this work, self-matched mode operation was provided by enhanced design of the perforations of the disk structure. Furthermore, a multi-axis BAW gyroscope, an extension of the z-axis, is developed. This novel approach avoids the issues associated with integrating multiple proof masses, permitting a very small form factor. The multi-axis gyroscopes operate in out-of plane and in-plane modes to measure the rotation rate around the x- and z-axes. These gyroscopes were also optimized to achieve self-matched mode operation in their both modes.

The object of this thesis research was to develop and characterize a new type of acoustic biosensor - a ZnO-based laterally excited thickness shear mode (TSM) resonator in a solidly mounted configuration. The first specific aim of the research was to develop the theoretical underpinnings of the acoustic wave propagation in ZnO. Theoretical calculations were carried out by solving the piezoelectrically stiffened Christoffel equation to elucidate the acoustic modes that are excited through lateral excitation of a ZnO stack. A finite element model was developed to confirm the calculations and investigate the electric field orientation and density for various electrode configurations. A proof of concept study was also carried out using a Quartz Crystal Microbalance device to investigate the application of thickness shear mode resonators to cancer biomarker detection in complex media. The results helped to provide a firm foundation for the design of new gravimetric sensors with enhanced capabilities. The second specific aim was to design and fabricate arrays of multiple laterally excited TSM devices and fully characterize their electrical properties. The solidly mounted resonator configuration was developed for the ZnO-based devices through theoretical calculations and experimentation. A functional mirror comprised of W and SiO2 was implemented in development of the TSM resonators. The devices were fabricated and tested for values of interest such as Q, and electromechanical coupling (K2) as well as their ability to operate in liquids. The third specific aim was to investigate the optimal surface chemistry scheme for linking the antibody layer to the ZnO device surface. Crosslinking schemes involving organosilane molecules and a phosphonic acid were compared for immobilizing antibodies to the surface of the ZnO. Results indicate that the thiol-terminated organosilane provides high antibody surface coverage and uniformity and is an excellent candidate for planar ZnO functionalization. The fourth and final specific aim was to investigate the sensitivity of the acoustic immunosensors to potential diagnostic biomarkers. Initial tests were performed in buffer spiked with varying concentrations of the purified target antigen to develop a dose-response curve for the detection of mesothelin-rFc. Subsequent tests were carried out in prostate cancer cell line conditioned medium for the detection of PSA. The results of the experiments establish the operation of the devices in complex media, and indicate that the acoustic sensors are sensitive enough for the detection of biomolecular targets at clinically relevant concentrations.