We present a fundamental class of 3D printed microfluidic circuit components and integrated syste... more We present a fundamental class of 3D printed microfluidic circuit components and integrated systems constructed using multijet modelling-based approaches.
2018 IEEE Micro Electro Mechanical Systems (MEMS), 2018
We demonstrate high-force-density rapid actuation of electrostatic gap-closing actuator (GCA) arr... more We demonstrate high-force-density rapid actuation of electrostatic gap-closing actuator (GCA) arrays operating in an aqueous environment. These devices are designed to generate up to 4.6 mN at 6 V drive signal amplitudes and have measured pull-in times as fast as 121 μs with no electrolysis. We present a new model for the dynamics of aqueous GCA operation which includes the inertia of the squeezed fluid and proximity of the substrate to the device layer. The actuators operate in deionized water, and preliminary tests demonstrate actuation in ionic solutions (10 mM) and partial operation of submerged inchworm motors based on GCA arrays.
we present the remote control of insects in free flight via an implantable radio-equipped miniatu... more we present the remote control of insects in free flight via an implantable radio-equipped miniature neural stimulating system. This paper summarizes these results. The pronotum mounted system consisted of neural stimulators, muscular stimulators, a radio transceiver-equipped microcontroller and a microbattery. Flight initiation, cessation and elevation control were accomplished through neural stimulus of the brain which elicited, suppressed or modulated wing oscillation. Turns were triggered through the direct muscular stimulus of either of the basalar muscles. We characterized the response times, success rates, and free-flight trajectories elicited by our neural control systems in remotely-controlled beetles. We believe this type of technology will open the door to in-flight perturbation and recording of insect flight responses. Keywords— micro air vehicle, biological machine, neuromuscular stimulation, flight control
In wireless devices, reducing the time the radio is on results in lower power consumption. In res... more In wireless devices, reducing the time the radio is on results in lower power consumption. In resource-constrained wireless networks, then, sending the same data in fewer bytes can greatly extend the lifetime of the network. In this paper, we explore the use of protocolindependent packet compression, a technique orthogonal to current explicit compaction techniques. Such a compression algorithm functions as a transparent layer inside a communication stack. Because it makes no assumption on the specific protocols used, it is generic enough to be used on multiple technologies. Compression is performed by identifying patterns in recently sent packets and replacing those patterns with bit flags, effectively reducing the size of the packet to be sent. We discuss the trade-offs between computation, memory costs and power savings in such an algorithm. We then present the results of compressing actual packet traces collected from several commercial networks using this algorithm. Results indi...
we present the remote control of insects in free flight via an implantable radio-equipped miniatu... more we present the remote control of insects in free flight via an implantable radio-equipped miniature neural stimulating system. This paper summarizes these results. The pronotum mounted system consisted of neural stimulators, muscular stimulators, a radio transceiver-equipped microcontroller and a microbattery. Flight initiation, cessation and elevation control were accomplished through neural stimulus of the brain which elicited, suppressed or modulated wing oscillation. Turns were triggered through the direct muscular stimulus of either of the basalar muscles. We characterized the response times, success rates, and free-flight trajectories elicited by our neural control systems in remotely-controlled beetles. We believe this type of technology will open the door to in-flight perturbation and recording of insect flight responses. Keywords— micro air vehicle, biological machine, neuromuscular stimulation, flight control
A MEMS actuator, dubbed the MEMS hammer, capable of storing and rapidly releasing mechanical ener... more A MEMS actuator, dubbed the MEMS hammer, capable of storing and rapidly releasing mechanical energy has been designed, built and tested. The hammer is fabricated using a single mask silicon-on-insulator (SOI) process. These devices have been used to study fracture in both lateral and vertical regimes. The lateral tests have shown excellent agreement with shear fracture theory. Using either a mechanical or an electrostatic latching mechanism, the hammers are capable of storing energies up to 3.3μJ. The hammers have been shown to displace up to 36μm, exert a maximum force of 240 mN, move at speeds exceeding 50m/s, and deliver at least 330 mW of mechanical power. INTRODUCTION The goal of this research is to create a microactuator capable of fracturing barriers made of silicon and silicon dioxide. At its core, the MEMS hammer is a device capable of storing and releasing mechanical energy. This system could be used for applications ranging from jumping microrobots [1] to needle-free deli...
Design, Automation & Test in Europe Conference & Exhibition (DATE), 2013, 2013
In the original demonstration of insect flight control [2,4], flight initiation, cessation and el... more In the original demonstration of insect flight control [2,4], flight initiation, cessation and elevation control were accomplished through neural stimulus of the brain which elicited, suppressed or modulated wing oscillation. Turns were triggered through the direct muscular stimulus of either of the basalar muscles. We characterized the response times, success rates, and free-flight trajectories elicited by our neural control systems in remotely controlled beetles.
Reuse of filtering facepiece respirators (FFRs, commonly referred to as N95s) normally meant for ... more Reuse of filtering facepiece respirators (FFRs, commonly referred to as N95s) normally meant for single use has become common in healthcare facilities due to shortages caused by the COVID-19 pandemic. Here, we report that murine hepatitis coronavirus initially seeded on FFR filter material is inactivated (6 order of magnitude reduction as measured by median tissue culture infective dose, TCID50) after dry heating at 75°C for 30 min. We also find that the quantitative fit of FFRs after heat treatment at this temperature, under dry conditions or at 90% relative humidity, is not affected by single or 10 heating cycles. Previous studies have reported that the filtration efficiency of FFRs is not negatively impacted by these heating conditions. These results suggest that thermal inactivation of coronaviruses is a potentially rapid and widely deployable method to reuse N95 FFRs in emergency situations where reusing FFRs is a necessity and broad-spectrum sterilization is unavailable. Howev...
Re-use of filtering facepiece respirators (FFRs, commonly referred to as N95s) normally meant for... more Re-use of filtering facepiece respirators (FFRs, commonly referred to as N95s) normally meant for single use only is becoming common in healthcare facilities due to shortages caused by the COVID19 pandemic. Here we report that mouse hepatitis virus (MHV) initially seeded on FFR filter material is inactivated (6 log reduction as measured by 50% tissue culture infective dose (TCID50)) after dry heating at 75 °C for 30 minutes. We also find that the quantitative fit of FFRs after heat treatment at this temperature, under dry conditions or at 90% relative humidity, is not affected by single or ten heating cycles. Previous studies have reported that the filtration efficiency of FFR filters is not negatively impacted by these heating conditions. These results suggest that thermal inactivation of coronaviruses is a potentially rapid and widely deployable method to re-use N95 FFRs in emergency situations where re-using FFRs is a necessity and broad-spectrum sterilization is unavailable. How...
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2018
Eliciting predictable flight responses in insects via exogenous stimulation of the nervous system... more Eliciting predictable flight responses in insects via exogenous stimulation of the nervous system is an area of both scientific and engineering interest. Blowflies in particular possess an excellent biological flight control system, making them an ideal system for characterising responses to stimulation. Here we demonstrate a means of electrically controlling Calliphoridae-Protophormia terranovae wing behaviour, generating a repeatable yaw response via biphasic electrical stimulation of the H1 lobula plate tangential cell (LPTC). We found that a 10 mA current pulse at a frequency of 30-270 Hz produces a yaw response in the preferred direction of H1 in a tethered blowfly preparation, and the magnitude of the yaw response is proportional to the frequency of the stimulus. This result suggests that these LPTCs, which encode optic flow, may be a viable interface for controlling fly flight behaviour. This platform could find application not only for micro air vehicles (MAVs), but also in ...
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2014
Linking neurons and muscles to their roles in behavior requires not only the ability to measure t... more Linking neurons and muscles to their roles in behavior requires not only the ability to measure their response during unrestrained movement but also the ability to stimulate them and observe the behavioral results. Current wireless stimulation technologies can be carried by rodent-sized animals and very large insects. However, the mass and volume of these devices make them impractical for studying smaller animals like insects. Here we present a battery-powered electronics platform suitable to be carried on a flying locust (2.7 g). The device has an IR-based (infrared) receiver, can deliver optical or electrical stimulation, occupies a volume of 0.1 cm(3), and weighs ~280 mg. We show the device is capable of powering two white SMD light emitting diodes (LEDs) for ~4 min and can be recharged in ~20 min. We demonstrate that our system shows no crosstalk with an IR-based Vicon tracking system. The entire package is made from commercial off-the-shelf components and requires no microfabri...
ABSTRACT For angiography, stem cell imaging, and cancer imaging, magnetic particle imaging (MPI) ... more ABSTRACT For angiography, stem cell imaging, and cancer imaging, magnetic particle imaging (MPI) can replace conventional techniques due to its safety in vivo, exquisite image contrast, and high detection sensitivity. However, compared to the theoretical physical sensitivity limit of a MPI scanner with 1 mm3 resolution using image 17 nm iron oxide nanoparticles, which lies between 100 nM and 1 μM1, the detection sensitivity for current MPI systems is worse by over 4 orders of magnitude. Factors contributing to this lack of sensitivity include non-optimal noise matching and feedthrough interference, of which the latter is a more dominant effect due to spectral overlap between the interfering signals and particle signals. Gleich et al., Schmale et al. and the authors of this study have previously attempted to decrease the interference through high-power filters and reducing capacitor distortion. In this work, we attempt to actively cancel interfering magnetic fields through the use of a feedforward transformer coupling circuit.
We present a fundamental class of 3D printed microfluidic circuit components and integrated syste... more We present a fundamental class of 3D printed microfluidic circuit components and integrated systems constructed using multijet modelling-based approaches.
2018 IEEE Micro Electro Mechanical Systems (MEMS), 2018
We demonstrate high-force-density rapid actuation of electrostatic gap-closing actuator (GCA) arr... more We demonstrate high-force-density rapid actuation of electrostatic gap-closing actuator (GCA) arrays operating in an aqueous environment. These devices are designed to generate up to 4.6 mN at 6 V drive signal amplitudes and have measured pull-in times as fast as 121 μs with no electrolysis. We present a new model for the dynamics of aqueous GCA operation which includes the inertia of the squeezed fluid and proximity of the substrate to the device layer. The actuators operate in deionized water, and preliminary tests demonstrate actuation in ionic solutions (10 mM) and partial operation of submerged inchworm motors based on GCA arrays.
we present the remote control of insects in free flight via an implantable radio-equipped miniatu... more we present the remote control of insects in free flight via an implantable radio-equipped miniature neural stimulating system. This paper summarizes these results. The pronotum mounted system consisted of neural stimulators, muscular stimulators, a radio transceiver-equipped microcontroller and a microbattery. Flight initiation, cessation and elevation control were accomplished through neural stimulus of the brain which elicited, suppressed or modulated wing oscillation. Turns were triggered through the direct muscular stimulus of either of the basalar muscles. We characterized the response times, success rates, and free-flight trajectories elicited by our neural control systems in remotely-controlled beetles. We believe this type of technology will open the door to in-flight perturbation and recording of insect flight responses. Keywords— micro air vehicle, biological machine, neuromuscular stimulation, flight control
In wireless devices, reducing the time the radio is on results in lower power consumption. In res... more In wireless devices, reducing the time the radio is on results in lower power consumption. In resource-constrained wireless networks, then, sending the same data in fewer bytes can greatly extend the lifetime of the network. In this paper, we explore the use of protocolindependent packet compression, a technique orthogonal to current explicit compaction techniques. Such a compression algorithm functions as a transparent layer inside a communication stack. Because it makes no assumption on the specific protocols used, it is generic enough to be used on multiple technologies. Compression is performed by identifying patterns in recently sent packets and replacing those patterns with bit flags, effectively reducing the size of the packet to be sent. We discuss the trade-offs between computation, memory costs and power savings in such an algorithm. We then present the results of compressing actual packet traces collected from several commercial networks using this algorithm. Results indi...
we present the remote control of insects in free flight via an implantable radio-equipped miniatu... more we present the remote control of insects in free flight via an implantable radio-equipped miniature neural stimulating system. This paper summarizes these results. The pronotum mounted system consisted of neural stimulators, muscular stimulators, a radio transceiver-equipped microcontroller and a microbattery. Flight initiation, cessation and elevation control were accomplished through neural stimulus of the brain which elicited, suppressed or modulated wing oscillation. Turns were triggered through the direct muscular stimulus of either of the basalar muscles. We characterized the response times, success rates, and free-flight trajectories elicited by our neural control systems in remotely-controlled beetles. We believe this type of technology will open the door to in-flight perturbation and recording of insect flight responses. Keywords— micro air vehicle, biological machine, neuromuscular stimulation, flight control
A MEMS actuator, dubbed the MEMS hammer, capable of storing and rapidly releasing mechanical ener... more A MEMS actuator, dubbed the MEMS hammer, capable of storing and rapidly releasing mechanical energy has been designed, built and tested. The hammer is fabricated using a single mask silicon-on-insulator (SOI) process. These devices have been used to study fracture in both lateral and vertical regimes. The lateral tests have shown excellent agreement with shear fracture theory. Using either a mechanical or an electrostatic latching mechanism, the hammers are capable of storing energies up to 3.3μJ. The hammers have been shown to displace up to 36μm, exert a maximum force of 240 mN, move at speeds exceeding 50m/s, and deliver at least 330 mW of mechanical power. INTRODUCTION The goal of this research is to create a microactuator capable of fracturing barriers made of silicon and silicon dioxide. At its core, the MEMS hammer is a device capable of storing and releasing mechanical energy. This system could be used for applications ranging from jumping microrobots [1] to needle-free deli...
Design, Automation & Test in Europe Conference & Exhibition (DATE), 2013, 2013
In the original demonstration of insect flight control [2,4], flight initiation, cessation and el... more In the original demonstration of insect flight control [2,4], flight initiation, cessation and elevation control were accomplished through neural stimulus of the brain which elicited, suppressed or modulated wing oscillation. Turns were triggered through the direct muscular stimulus of either of the basalar muscles. We characterized the response times, success rates, and free-flight trajectories elicited by our neural control systems in remotely controlled beetles.
Reuse of filtering facepiece respirators (FFRs, commonly referred to as N95s) normally meant for ... more Reuse of filtering facepiece respirators (FFRs, commonly referred to as N95s) normally meant for single use has become common in healthcare facilities due to shortages caused by the COVID-19 pandemic. Here, we report that murine hepatitis coronavirus initially seeded on FFR filter material is inactivated (6 order of magnitude reduction as measured by median tissue culture infective dose, TCID50) after dry heating at 75°C for 30 min. We also find that the quantitative fit of FFRs after heat treatment at this temperature, under dry conditions or at 90% relative humidity, is not affected by single or 10 heating cycles. Previous studies have reported that the filtration efficiency of FFRs is not negatively impacted by these heating conditions. These results suggest that thermal inactivation of coronaviruses is a potentially rapid and widely deployable method to reuse N95 FFRs in emergency situations where reusing FFRs is a necessity and broad-spectrum sterilization is unavailable. Howev...
Re-use of filtering facepiece respirators (FFRs, commonly referred to as N95s) normally meant for... more Re-use of filtering facepiece respirators (FFRs, commonly referred to as N95s) normally meant for single use only is becoming common in healthcare facilities due to shortages caused by the COVID19 pandemic. Here we report that mouse hepatitis virus (MHV) initially seeded on FFR filter material is inactivated (6 log reduction as measured by 50% tissue culture infective dose (TCID50)) after dry heating at 75 °C for 30 minutes. We also find that the quantitative fit of FFRs after heat treatment at this temperature, under dry conditions or at 90% relative humidity, is not affected by single or ten heating cycles. Previous studies have reported that the filtration efficiency of FFR filters is not negatively impacted by these heating conditions. These results suggest that thermal inactivation of coronaviruses is a potentially rapid and widely deployable method to re-use N95 FFRs in emergency situations where re-using FFRs is a necessity and broad-spectrum sterilization is unavailable. How...
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2018
Eliciting predictable flight responses in insects via exogenous stimulation of the nervous system... more Eliciting predictable flight responses in insects via exogenous stimulation of the nervous system is an area of both scientific and engineering interest. Blowflies in particular possess an excellent biological flight control system, making them an ideal system for characterising responses to stimulation. Here we demonstrate a means of electrically controlling Calliphoridae-Protophormia terranovae wing behaviour, generating a repeatable yaw response via biphasic electrical stimulation of the H1 lobula plate tangential cell (LPTC). We found that a 10 mA current pulse at a frequency of 30-270 Hz produces a yaw response in the preferred direction of H1 in a tethered blowfly preparation, and the magnitude of the yaw response is proportional to the frequency of the stimulus. This result suggests that these LPTCs, which encode optic flow, may be a viable interface for controlling fly flight behaviour. This platform could find application not only for micro air vehicles (MAVs), but also in ...
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2014
Linking neurons and muscles to their roles in behavior requires not only the ability to measure t... more Linking neurons and muscles to their roles in behavior requires not only the ability to measure their response during unrestrained movement but also the ability to stimulate them and observe the behavioral results. Current wireless stimulation technologies can be carried by rodent-sized animals and very large insects. However, the mass and volume of these devices make them impractical for studying smaller animals like insects. Here we present a battery-powered electronics platform suitable to be carried on a flying locust (2.7 g). The device has an IR-based (infrared) receiver, can deliver optical or electrical stimulation, occupies a volume of 0.1 cm(3), and weighs ~280 mg. We show the device is capable of powering two white SMD light emitting diodes (LEDs) for ~4 min and can be recharged in ~20 min. We demonstrate that our system shows no crosstalk with an IR-based Vicon tracking system. The entire package is made from commercial off-the-shelf components and requires no microfabri...
ABSTRACT For angiography, stem cell imaging, and cancer imaging, magnetic particle imaging (MPI) ... more ABSTRACT For angiography, stem cell imaging, and cancer imaging, magnetic particle imaging (MPI) can replace conventional techniques due to its safety in vivo, exquisite image contrast, and high detection sensitivity. However, compared to the theoretical physical sensitivity limit of a MPI scanner with 1 mm3 resolution using image 17 nm iron oxide nanoparticles, which lies between 100 nM and 1 μM1, the detection sensitivity for current MPI systems is worse by over 4 orders of magnitude. Factors contributing to this lack of sensitivity include non-optimal noise matching and feedthrough interference, of which the latter is a more dominant effect due to spectral overlap between the interfering signals and particle signals. Gleich et al., Schmale et al. and the authors of this study have previously attempted to decrease the interference through high-power filters and reducing capacitor distortion. In this work, we attempt to actively cancel interfering magnetic fields through the use of a feedforward transformer coupling circuit.
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