The purpose of this effort is to investigate whether large acoustic pressure waves can be transmitted inside beverage containers to enable pasteurization. Acoustic waves are known to induce large nonlinear compressive forces and shock waves in fluids, suggesting that compression waves may be capable of damaging bacteria inside beverage containers without appreciably increasingly the temperature or altering the freshness and flavor of the beverage contents. Although a combined process such as thermosonication (e.g., sonication with heating) is likely more efficient, it is instructive to compute the acoustic pressure field distribution inside the beverage container. The COMSOL simulations used two and three-dimensional models of beverage containers placed in a water bath to compute the acoustic pressure field. A limitation of these COMSOL models is that they cannot determine the bacterial lysis efficiency, rather the models provide an indirect metric of bacterial lysis based on the magnitude of the pressure field and its distribution.
Paldia, Robynne L.; Qia, Zhimin Q.; Misaa, Shikhar M.; Lua, Juanjuan L.; Suna, Xing S.; Phuaha, Xin L.; Branch, Darren W.; Siddiqui, Aleem M.; Wanga, Haiyan W.
Epitaxial lithium niobate (LNO) thin films are an attractive material for devices across a broad range of fields, including optics, acoustics, and electronics. These applications demand high-quality thin films without in-plane growth domains to reduce the optical/acoustical losses and optimize efficiency. Twin-free single-domain-like growth has been achieved previously, but it requires specific growth conditions that might be hard to replicate. In this work, a versatile nanocomposite-seeded approach is demonstrated as an effective approach to grow single-domain epitaxial lithium niobate thin films. Films are grown through a pulsed laser deposition method and growth conditions are optimized to achieve high-quality epitaxial film. A comprehensive microstructure characterization is performed and optical properties are measured. A piezoelectric acoustic resonator device is developed to demonstrate the future potential of the nanocomposite-seeded approach for high-quality LNO growth for radio frequency (RF) applications.
IFCS-ISAF 2020 - Joint Conference of the IEEE International Frequency Control Symposium and IEEE International Symposium on Applications of Ferroelectrics, Proceedings
A true series resonance oscillator has been developed for use with a wide-range of 1-port resonance-based sensors and devices. The oscillator effectively removes the shunt capacitance Co, allowing the true series resonance to be monitored, providing the optimum sensitivity across a wide range of frequencies (i.e. kilohertz to gigahertz), shunt capacitances, and quality factors (Q) for the first time. It is well-known that non-zero shunt capacitance alters the impedance by shifting the location of the impedance minimum and the zero-phase crossing while causing significant impedance distortion. We have developed an active shunt capacitance cancelling oscillator (ASSCO) that removes any shunt capacitance across the resonator by supplying the circuit an equal 'dummy' capacitance using a cancelling current. The oscillator does not require automatic gain control (AGC) and the resonator can be grounded to reduce parasitic contributions.
Miniature ultrasonic lysis for biological sample preparation is a promising technique for efficient and rapid extraction of nucleic acids and proteins from a wide variety of biological sources. Acoustic methods achieve rapid, unbiased, and efficacious disruption of cellular membranes while avoiding the use of harsh chemicals and enzymes, which interfere with detection assays. In this work, a miniature acoustic nucleic acid extraction system is presented. Using a miniature bulk acoustic wave (BAW) transducer array based on 36° Y-cut lithium niobate, acoustic waves were coupled into disposable laminate-based microfluidic cartridges. To verify the lysing effectiveness, the amount of liberated ATP and the cell viability were measured and compared to untreated samples. The relationship between input power, energy dose, flow-rate, and lysing efficiency were determined. DNA was purified on-chip using three approaches implemented in the cartridges: a silica-based sol-gel silica-bead filled microchannel, nucleic acid binding magnetic beads, and Nafion-coated electrodes. Using E. coli, the lysing dose defined as ATP released per joule was 2.2× greater, releasing 6.1× more ATP for the miniature BAW array compared to a bench-top acoustic lysis system. An electric field-based nucleic acid purification approach using Nafion films yielded an extraction efficiency of 69.2% in 10 min for 50 μL samples.
Branch, Darren W.; Smith, Gennifer T.; Vreeland, Erika C.; Blakemore, Robert; Alland, David
We have developed a miniature ultrasonic lysing system for the rapid release and extraction of Mycobacterium Tuberculosis (MTB) DNA. The prototype consists of two key sections, a disposable plastic manifold that hold sputum slides and a plastic cartridge with five fluidic DNA extraction channels. The MTB vaccine Bacillus Calmette-Guérin (BCG) was used as a simulant for MTB for all the lysing studies. The slide manifold houses up to five individual sputum slides and is processed by a computer to fill and load the cartridges with sputum suspensions from each slide. The plastic cartridge was developed to facilitate acoustic coupling through the bottom interface such that MTB/BCG can be lysed remotely. The disposable cartridge eliminated cross contamination problems and additional cleaning time. Due to the high power density, only 66 mW was required to lyse microliter BCG samples at the same level as the positive control (i.e. boiling for 30 minutes at 95 °C).
Eliminating spurious modes in Aluminum Nitride (AlN) microresonators improves their insertion loss and quality factor by reducing acoustic energy leakage. Spurious modes that result from transverse wave propagation, termed fine-frequency modes, leak energy and propagate in the electrical busing and appear near the fundamental resonance. Although these modes can be predicted using three-dimensional (3D) finite element methods (FEM) for devices with very short acoustic length (e.g. 1 acoustic wavelength), 3D FEM is very slow and memory intensive when compared to a two-dimensional (2D) simulation. A fast 2D coupling-of-modes (COM) model was developed to predict, identify and implement strategies to suppress the fine-frequency modes.
Bioweapons and emerging infectious diseases pose growing threats to our national security. Both natural disease outbreak and outbreaks due to a bioterrorist attack are a challenge to detect, taking days after the outbreak to identify since most outbreaks are only recognized through reportable diseases by health departments and reports of unusual diseases by clinicians. In recent decades, arthropod-borne viruses (arboviruses) have emerged as some of the most significant threats to human health. They emerge, often unexpectedly, from cryptic transmission foci causing localized outbreaks that can rapidly spread to multiple continents due to increased human travel and trade. Currently, diagnosis of acute infections requires amplification of viral nucleic acids, which can be costly, highly specific, technically challenging and time consuming. No diagnostic devices suitable for use at the bedside or in an outbreak setting currently exist. The original goals of this project were to 1) develop two highly sensitive and specific diagnostic assays for detecting RNA from a wide range of arboviruses; one based on an electrochemical approach and the other a fluorescent based assay and 2) develop prototype microfluidic diagnostic platforms for preclinical and field testing that utilize the assays developed in goal 1. We generated and characterized suitable primers for West Nile Virus RNA detection. Both optical and electrochemical transduction technologies were developed for DNA-RNA hybridization detection and were implemented in microfluidic diagnostic sensing platforms that were developed in this project.
This report describes X-cut lithium niobates (LiNbO3) utilization for voltage sensing by monitoring the acoustic wave propagation changes through LiNbO3 resulting from applied voltage. Direct current (DC), alternating current (AC) and pulsed voltage signals were applied to the crystal. Voltage induced shift in acoustic wave propagation time scaled quadratically for DC and AC voltages and linearly for pulsed voltages. The measured values ranged from 10 - 273 ps and 189 ps 2 ns for DC and non-DC voltages, respectively. Data suggests LiNbO3 has a frequency sensitive response to voltage. If voltage source error is eliminated through physical modeling from the uncertainty budget, the sensors U95 estimated combined uncertainty could decrease to ~0.025% for DC, AC, and pulsed voltage measurements.
This work demonstrates a lateral overtone bulk acoustic resonator (LOBAR), which consists of an aluminum nitride (AlN) transducer coupled to a suspended thin silicon carbide (SiC) film fabricated using standard CMOS-compatible processes. The LOBAR design allows for high transduction efficiency and quality factors, by decoupling the transduction and energy storage schemes in the resonator. The frequency and bandwidth of the resonator were lithographically defined and controlled. A LOBAR operating at 2.93GHz with a Q greater than 100,000 in air was fabricated and characterized, having the highest reported f×Q product of any acoustic resonator to date.
Recently reported narrow bandwidth, <;2%, aluminum nitride microresonator filters in the 100-500 MHz range offer lower insertion loss, 100x smaller size, and elimination of large external matching networks, when compared to similar surface acoustic wave filters. While the initial results are promising, many microresonators exhibit spurious responses both close and far from the pass band which degrade the out of band rejection and prevent the synthesis of useful filters. This paper identifies the origins of several unwanted modes in overtone width extensional aluminum nitride microresonators and presents techniques for mitigating the spurious responses.
While individual neurons function at relatively low firing rates, naturally-occurring nervous systems not only surpass manmade systems in computing power, but accomplish this feat using relatively little energy. It is asserted that the next major breakthrough in computing power will be achieved through application of neuromorphic approaches that mimic the mechanisms by which neural systems integrate and store massive quantities of data for real-time decision making. The proposed LDRD provides a conceptual foundation for SNL to make unique advances toward exascale computing. First, a team consisting of experts from the HPC, MESA, cognitive and biological sciences and nanotechnology domains will be coordinated to conduct an exercise with the outcome being a concept for applying neuromorphic computing to achieve exascale computing. It is anticipated that this concept will involve innovative extension and integration of SNL capabilities in MicroFab, material sciences, high-performance computing, and modeling and simulation of neural processes/systems.
The rapid autonomous detection of pathogenic microorganisms and bioagents by field deployable platforms is critical to human health and safety. To achieve a high level of sensitivity for fluidic detection applications, we have developed a 330 MHz Love wave acoustic biosensor on 36{sup o} YX Lithium Tantalate (LTO). Each die has four delay-line detection channels, permitting simultaneous measurement of multiple analytes or for parallel detection of single analyte containing samples. Crucial to our biosensor was the development of a transducer that excites the shear horizontal (SH) mode, through optimization of the transducer, minimizing propagation losses and reducing undesirable modes. Detection was achieved by comparing the reference phase of an input signal to the phase shift from the biosensor using an integrated electronic multi-readout system connected to a laptop computer or PDA. The Love wave acoustic arrays were centered at 330 MHz, shifting to 325-328 MHz after application of the silicon dioxide waveguides. The insertion loss was -6 dB with an out-of-band rejection of 35 dB. The amplitude and phase ripple were 2.5 dB p-p and 2-3{sup o} p-p, respectively. Time-domain gating confirmed propagation of the SH mode while showing suppression of the triple transit. Antigen capture and mass detection experiments demonstrate a sensitivity of 7.19 {+-} 0.74{sup o} mm{sup 2}/ng with a detection limit of 6.7 {+-} 0.40 pg/mm{sup 2} for each channel.
Recently, the generalized method for calculation of the 16-element Green's function for analysis of surface acoustic waves has proven crucial to develop more sophisticated transducers. The generalized Green's function provides a precise relationship between the acoustic stresses and electric displacement on the three mechanical displacements and electric potential. This generalized method is able to account for mass loading effects which is absent in the effective permittivity approach. However, the calculation is numerically intensive and may lead to numerical instabilities when solving for both the eigenvalues and eigenvectors simultaneously. In this work, the general eigenvalue problem was modified to eliminate the numerical instabilities in the solving procedure. An algorithm is also presented to select the proper eigenvalues rapidly to facilitate analysis for all types of acoustic propagation. The 4 x 4 Green's functions and effective permittivities were calculated for materials supporting Rayleigh, leaky, and leaky longitudinal waves as demonstration of the method.
Flow cytometry is an indispensable tool in clinical diagnostics, for example in cancer, AIDS, infectious disease outbreaks, microbiology, and others. The cost and size of existing cytometers precludes their entry into field clinics, water monitoring, agriculture/veterinary diagnostics, and rapidly deployable biothreat detection. Much of the cost and footprint of conventional cytometers is dictated by the high speed achieved by cells or beads in a hydrodynamically focused stream. This constraint is removed by using ultrasonic focusing in a parallel microfluidic architecture. In this paper, we describe our progress towards a microfabricated flow cytometer that uses bulk and microfabricated planar piezoelectric transducers in glass microfluidic channels. In addition to experimental data, initial modeling data to predict the performance of our transducers are discussed.
Crucial to low-level detection of biowarfare agents in aqueous environments is the mass sensitivity optimization of Love-wave acoustic sensors. The present work is an experimental study of 36{sup o} YX cut LiTaO{sub 3} based Love-wave devices for detection of pathogenic spores in aqueous conditions. Given that the detection limit (DL) of Love-wave based sensors is a strong function of the overlying waveguide, two waveguide materials have been investigated, which are polyimide and polystyrene. To determine the mass sensitivity of Love-wave sensor, bovine serum albumin (BSA) protein was injected into the Love-wave test cell while recording magnitude and phase shift across each sensor. Polyimide had the lowest mass detection limit with an estimated value of 1-2 ng/cm{sup 2}, as compared to polystyrene where DL = 2.0 ng/cm{sup 2}. Suitable chemistries were used to orient antibodies on the Love-wave sensor using adsorbed protein G. The thickness of each biofilm was measured using ellipsometry from which the surface concentrations were calculated. The monoclonal antibody BD8 with a high degree of selectivity for anthrax spores was used to capture the non-pathogenic simulant B. thuringiensis B8 spores. Bacillus Subtilis spores were used as a negative control to determine whether significant non-specific binding would occur. Spore aliquots were prepared using an optical counting method, which permitted removal of background particles for consistent sample preparation. This work demonstrates that Love-wave devices can be used to detect B. anthracis simulant below reported infectious levels.
Impedance based, planar chemical microsensors are the easiest sensors to integrate with electronics. The goal of this work is a several order of magnitude increase in the sensitivity of this sensor type. The basic idea is to mimic biological chemical sensors that rely on changes in ion transport across very thin organic membranes (supported Bilayer Membranes: sBLMs) for the sensing. To improve the durability of bilayers we show how they can be supported on planar metal electrodes. The large increase in sensitivity over polyelectrolytes will come from molecular recognition elements like antibodies that bind the analyte molecule. The molecular recognition sites can be tied to the lipid bilayer capacitor membrane and a number of mechanisms can be used to modulate the impedance of the lipid bilayers. These include coupled ion channels, pore modification and double layer capacitance modification by the analyte molecule. The planar geometry of our electrodes allows us to create arrays of sensors on the same chip, which we are calling the ''Lipid Chip''.