Smart sensors are needed to achieve a more intelligent aero-engine. The thin-film sensor array is thereby fabricated on the turbine blade surface using MEMS technology to measure the surface ...temperature distribution for the first time. A series of PtRh/Pt thin film thermocouple (TFTC) is directly integrated in-situ on blade surface by dry film photolithography and magnetron sputtering technology. A series of high temperature experiments are performed to test its annealing effect, stability and repeatability, responsiveness, and temperature distribution. The experimental results show that after annealing at 800 °C for 1 hour, TFTCs exhibit good stability and consistency. This TFTC array can capture the temperature distribution caused by the heat flame on the blade surface, and the transient temperature responsiveness can reach at least <inline-formula> <tex-math notation="LaTeX">10~\mu \text{s} </tex-math></inline-formula> under a dynamic heat flow. The TFTC is only <inline-formula> <tex-math notation="LaTeX">1~\mu \text{m} </tex-math></inline-formula> thick thin film coated on the blade surface and the thin film routing can direct the joint connection to the edge of the blade, hence causing minimum surface heat flow patterns and structure modulation. Therefore such TFTC array is very useful for accurate transient temperature measurements such as on turbine blade surface, comparing to the wired thermocouple method.
High temperature measurement of the rotating parts in aero-engine system requires wireless passive sensors. Surface acoustic wave (SAW) devices capable of measuring high temperature wirelessly are ...therefore ideal for these extreme scenarios where wired sensors are not applicable. In this article, SAW sensors built on the LiNbO 3 substrate which can measure up to 1100 °C with a good repeatability and endurance are reported. The platinum IDT and LiNbO 3 substrate were effectively protected by a SiO 2 passivation layer to ensure the functionality and stability of the SAW devices under extremely high temperature. Distinct linearity of f 0 vs. temperature, together with the temperature durability of the SAW sensors were verified by conducting various high-temperature RF tests. Such a SAW sensor attached with an embedded near-field antenna was also formulated to enhance the wireless transmission quality for future high-temperature remote sensing system.
A new quasi-Coulomb relation between magnetic force vs distance, magnetic flux density, and magnetic pole area is proposed in this paper based on the empirical analysis on the magnetic force vs ...distance measurements. A simple device is designed and fabricated to measure the repulsive/attractive magnetic force between two magnets. The measurement results show that the relationship between the magnetic force and distance is similar to Coulomb’s electrostatic law, but the attraction is greater than the repulsion. The magnetic force is proportional to the integral of the magnetic flux density with the areas of the magnetic pole. This quasi-Coulomb relationship is useful to evaluate the torque and speed of a rim-driven motor, which plays an important role in electrified propulsion in green aviation technology.
The surface acoustic wave (SAW) device can be used to measure temperature wirelessly, which is highly adaptable to the use in aero-engines high-temperature test scenarios where wired-sensors is not ...suitable for its difficulty in signal transfers. Herein, this paper presents a SAW sensor capable of achieving high-temperature measurement up to 800 °C with a good repeatability. The sensor is built on 41°Y LiNbO 3 substrate with a SiO 2 passivation. With the protection of SiO 2 layer, the volatilization of platinum is effectively prevented to ensure SAW's stability at a higher temperature. At the same time, SiO 2 layer also protects the lithium niobate substrate, according to our verification result of XRD and EDS. Both crystal orientation and chemical composition of LiNbO 3 substrate have been maintained after high-temperature testing. The temperature coefficient factor TCF is -2.98KHz/°C for our passivated SAW devices with a good linearity and repeatability.
High performance turbine blade for advanced aero-engines needs a low thermal-conductive layer to buffer surface heat from the base metal. Since air possesses lowest thermal conductivity, adding the ...air ingredient into the solid material or increasing the porosity will accordingly improve the thermal buffering effect of this layer. In this paper, this principle is demonstrated by etching deep trench in silicon wafer with ICP technique, by ionized porous Ti surface, by nested copper and nickel structures and by varying porosity in YSZ film. SEM and AFM characterization as well as delicate thermal conductivity measurements were conducted for visual observation and thermal conductivity evaluations. The thermal insulation properties of these porous structures above were also extensively studied by numerical computer simulations with various air-filling situations. Results revealed that noticeable thermal buffering effect would occur when enough amount of air (above 60%) was filled into the solid in the material processing.
This article presents the development of a stretchable sensor network with high signal-to-noise ratio and measurement accuracy for real-time distributed sensing and remote monitoring. The described ...sensor network was designed as an island-and-serpentine type network comprising a grid of sensor "islands" connected by interconnecting "serpentines." A novel high-yield manufacturing process was developed to fabricate networks on recyclable 4-inch wafers at a low cost. The resulting stretched sensor network has 17 distributed and functionalized sensing nodes with low tolerance and high resolution. The sensor network includes Piezoelectric (PZT), Strain Gauge (SG), and Resistive Temperature Detector (RTD) sensors. The design and development of a flexible frame with signal conditioning, data acquisition, and wireless data transmission electronics for the stretchable sensor network are also presented. The primary purpose of the frame subsystem is to convert sensor signals into meaningful data, which are displayed in real-time for an end-user to view and analyze. The challenges and demonstrated successes in developing this new system are demonstrated, including (a) developing separate signal conditioning circuitry and components for all three sensor types (b) enabling simultaneous sampling for PZT sensors for impact detection and (c) configuration of firmware/software for correct system operation. The network was expanded with an in-house developed automated stretch machine to expand it to cover the desired area. The released and stretched network was laminated into an aerospace composite wing with edge-mount electronics for signal conditioning, processing, power, and wireless communication.
Whether changes in oxygen metabolism, as measured by oxygen consumption (VO2), carbon dioxide production (VCO2) and the respiratory exchange ratio (RER), are associated with survival after cardiac ...arrest is poorly understood. In this prospective observational study, we investigated the association between VO2, VCO2, and RER in the initial 12 and 24 h after return of spontaneous circulation (ROSC) and survival to hospital discharge.
Adults with ROSC after cardiac arrest, admitted to the intensive care unit, requiring mechanical ventilation and treated with targeted temperature management were included. VO2 and VCO2 were measured continuously for 24 h after ROSC, using a noninvasive anesthesia monitor. Area under the curve for VO2, VCO2 & RER was calculated using all available values over 12 and 24 h after ROSC. Using logistic regression, we evaluated the relationship between these metabolic variables and survival to hospital discharge. Analyses were adjusted for temperature, vasopressors, and neuromuscular blockade.
Sixty four patients were included. Mean age was 64 ± 16 years, and 59% were women. There was no significant association between the area under the curve of VO2 or VCO2 and survival. A higher RER in the initial 12 h was associated with better survival (aOR = 3.97, 95% CI 1.01,15.6, p = 0.048). Survival was lower in those with median RER < 0.7 in the initial 12 h compared with those with a median RER ≥ 0.7 (25% vs 67%, p = 0.011).
Higher RER in the initial 12 h was associated with survival after cardiac arrest. The etiology of unusually low RERs in this patient population remains unclear.
FMT Li, Franklin Mingzhe; Chen, Di Laura; Fan, Mingming ...
Proceedings of ACM on interactive, mobile, wearable and ubiquitous technologies,
09/2019, Letnik:
3, Številka:
3
Journal Article
Recenzirano
Older adults sometimes forget about whether or not they have completed routine actions and the states of objects that they have interacted with (e.g., the kitchen stove is on or off). In this work, ...we explore whether video clips captured from a body-worn camera every time objects of interest are found within its field of view can help older adults determine if they have completed certain actions with these objects and what their states are. We designed FMT ("Fiducial Marker Tracker")---a real-time capture and access application that opportunistically captures video clips of objects the user interacts with. To do this, the user places fiducial markers close to objects which would be captured when the marker enters the user's body-worn camera's field of view. We examine and discuss what objects this system would be best suited to track, and the usefulness and usability of this approach. FMT successfully captured direct interactions with an object at an average rate of 75.6% across all participants (SD = 9.9%). Our results also reveal how, what, and why users would use such a system for help.
Nanoelectronic devices are being extensively developed in these years with a large variety of potential applications. In this article, some recent developments in nanoelectronic devices, including ...their principles, structures and potential applications are reviewed. As nanodevices work in nanometer dimensions, they consume much less power and function much faster than conventional microelectronic devices. Nanoelectronic devices can operate in different principles so that they can be further grouped into field emission devices,molecular devices, quantum devices, etc. Nanodevices can function as sensors, diodes, transistors, photovoltaic and light emitting devices, etc. Recent advances in both theoretical simulation and fabrication technologies expedite the development process from device design to prototype demonstration. Practical applications with a great market value from nanoelectronic devices are expected in near future.
The transistor threshold voltage mismatch and sensing noise are larger with technology scaling, while the sensing voltage difference of bit-line sense amplifier becomes smaller. Though various offset ...calibration techniques have been adopted in bit-line sense amplifiers to compensate for the offset mismatch, sensing offset and noise are still critical issues to limit the sensing margin. This brief proposes a bit-line sense amplifier with asymmetrically controlled isolation devices to solve the sensing offset and sensing noise problems simultaneously. Being biased to the calibration point, the target inverter acts as an amplifier with a large voltage gain (AV) to boost the sensing voltage difference, making the sensing voltage difference of the proposed amplifier be 1 + |AV| times that of a conventional latch-type sense amplifier. And the pre-sensing operation performs in parallel with boosting to suppress the sensing noise, without additional time and area consumption. By offset calibration and voltage difference boosting techniques, the proposed design has suppressed the sensing noise and enhanced the sensing margin. All designs are implemented on SMIC 40-nm technology, operating at a supply voltage of 1.05 V or less. The proposed sense amplifier has reduced the standard deviation of the decision threshold voltage to 0.62× and improved the sensing yield by 17.96%. In addition, the boosted sensing voltage difference speeds up the sensing stage, compensating for the pre-sensing time by 36%. Keeping the same number of transistors as the prior offset mismatch calibration sense amplifier, the proposed sense amplifier with improved sensing margin is suitable for low-voltage and high-density DRAM.
•Isolation transistors are asymmetrically controlled and time-share enabled.•The sensing voltage difference is boosted to be (1 + |AV |) times that of a conventional sense amplifier.•The pre-sensing operation performs in parallel with the snesing voltage difference boosting operation.•The standard deviation of the decision threshold voltage is reduced by 0.62 × .•The sensing yield is over 84% at 0.80 V, which is higher than that of the prior work at 1.05 V.
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