Distilling determination of water content in hydraulic oil with a ZnO/glass surface acoustic wave device

Detection of water content in hydraulic oil is critical to identify abnormal wear conditions for purpose of predicting possible machinery failure in hydraulic systems. The paper reports a feasibility study of measuring the water content in the hydraulic oil using a ZnO thin film surface acoustic wave (SAW) device combined with the standard distillation method. The shift of resonant frequency of the SAW device increases with the increase of water content in hydraulic oil, and reaches 919 kHz for 0.80 wt% water content in oil samples. The results indicate that the ZnO SAW sensor can detect water content in hydraulic oil with high sensitivity

Flexible Surface Acoustic Wave Humidity Sensor with on Chip Temperature Compensation

AbstractThis paper reports the development of flexible surface acoustic wave (SAW) based humidity sensors on polyimide substrate. The SAW devices have two resonant peaks, named the A0 and S0 Lamb modes, which have different temperature coefficients of frequency. Graphene oxide (GO) is used as the sensing layer owing to its large surface area and hydrophilcity to water. The sensors show high sensitivity up to 145.83ppm/%RH, comparable to those on rigid substrates, and fast response time of 4.4s. The sensitivity increases with the increase of GO thickness and resonant frequency. By utilizing the S0 mode as the temperature reference, a SAW Humidity-sensor with an on chip temperature compensation capability is demonstrated. The humidity sensors also show the ability to work under severe bending condition, demonstrated its great potential for flexible/wearable applications

High sensitivity flexible Lamb-wave humidity sensors with a graphene oxide sensing layer

This paper reports high performance flexible Lamb wave humidity sensors with a graphene oxide sensing layer. The devices were fabricated on piezoelectric ZnO thin films deposited on flexible polyimide substrates. Two resonant peaks, namely the zero order antisymmetric (A0) and symmetric (S0) mode Lamb waves, were observed and fitted well with the theoretical analysis and modelling. With graphene oxide microflakes as the sensing layer, the sensing performance of both wave modes was investigated. The humidity sensitivity of the A0 mode is 145.83 ppm per %RH (at humidity 85%RH), higher than that of S0 mode of 89.35 ppm per %RH. For the first time, we have demonstrated that the flexible humidity sensors work as usual without noticeable deterioration in performance even under severe bending conditions up to 1500 με. Also the sensors showed an excellent stability upon repeated bending for thousand times. All the results demonstrated that the Lamb wave flexible humidity sensors have a great potential for application in flexible electronics

Triboelectric effect based instantaneous self-powered wireless sensing with self-determined identity

Sensors are the foundation of modern Internet of Things, artificial intelligent, smart manufacturing etc, but most of them require power to operate without spontaneous unique identifiable function. Herein we propose a novel instantaneous force-driven self-powered self-identified wireless sensor based on triboelectric effect to meet the huge demand of true self-powered wireless sensors. The device consists of a microswitch controlled triboelectric nanogenerator (TENG) in parallel with a capacitor-inductor oscillating circuit, and a wireless transmitter. The system is fully powered by the output of the TENG to generate a resonant frequency containing sensing and device identity information, which is then coupled to the transmitter for realizing a long-range wireless communication. The device, with the multiple functions of energy harvesting, sensing, identity generation and wireless signal transmission, is a standalone device, which responds to each trigger without losing sensing information. It eliminates the requirement of electric components for traditional wireless communication, such as rectification circuit, energy storage units, microprocessor, wireless communication chip, etc. Thus, we developed a true self-powered identifiable wireless sensor with great potential for widespread applications

A novel ATP dependent dimethylsulfoniopropionate lyase in bacteria that releases dimethyl sulfide and acryloyl-CoA

Dimethylsulfoniopropionate (DMSP) is an abundant and ubiquitous organosulfur molecule in marine environments with important roles in global sulfur and nutrient cycling. Diverse DMSP lyases in some algae, bacteria and fungi cleave DMSP to yield gaseous dimethyl sulfide (DMS), an infochemical with important roles in atmospheric chemistry. Here we identified a novel ATP-dependent DMSP lyase, DddX. DddX belongs to the acyl-CoA synthetase superfamily and is distinct from the eight other known DMSP lyases. DddX catalyses the conversion of DMSP to DMS via a two-step reaction: the ligation of DMSP with CoA to form the intermediate DMSP-CoA, which is then cleaved to DMS and acryloyl-CoA. The novel catalytic mechanism was elucidated by structural and biochemical analyses. DddX is found in several Alphaproteobacteria, Gammaproteobacteria and Firmicutes, suggesting that this new DMSP lyase may play an overlooked role in DMSP/DMS cycles

Analysis of Hydraulic Performance and Flow Characteristics of Inlet and Outlet Channels of Integrated Pump Gate

The integrated pump gate structure can improve the shortcomings of traditional asymmetric pumping stations with large floor space, but its internal flow mechanism is not clear, which affects its efficient, stable, and safe operation. In order to reveal its internal fluid flow characteristics, numerical simulations based on the N-S equation with the SST k-ω turbulence model are used in this paper, and experimental validation is carried out. The test results yielded an efficiency of 60.50% near the design flow condition, corresponding to a flow rate of 11.5 L/s, a head of 2.7569 m, a hydraulic loss of 0.064 m in the inlet channel, and a hydraulic loss of 1.337 m in the outlet channel. The integrated pump gate has a uniform inlet water flow pattern, less undesirable flow pattern, and a large backflow vortex in the outlet water. This paper reveals the internal flow characteristics of its integrated pump gate inlet and outlet water, and the research results can provide some reference for the design, theoretical analysis, and application of similar integrated pump gates

Analysis of Hydraulic Performance and Flow Characteristics of Inlet and Outlet Channels of Integrated Pump Gate

The integrated pump gate structure can improve the shortcomings of traditional asymmetric pumping stations with large floor space, but its internal flow mechanism is not clear, which affects its efficient, stable, and safe operation. In order to reveal its internal fluid flow characteristics, numerical simulations based on the N-S equation with the SST k-ω turbulence model are used in this paper, and experimental validation is carried out. The test results yielded an efficiency of 60.50% near the design flow condition, corresponding to a flow rate of 11.5 L/s, a head of 2.7569 m, a hydraulic loss of 0.064 m in the inlet channel, and a hydraulic loss of 1.337 m in the outlet channel. The integrated pump gate has a uniform inlet water flow pattern, less undesirable flow pattern, and a large backflow vortex in the outlet water. This paper reveals the internal flow characteristics of its integrated pump gate inlet and outlet water, and the research results can provide some reference for the design, theoretical analysis, and application of similar integrated pump gates

AlScN thin film based surface acoustic wave devices with enhanced microfluidic performance

This paper reports the characterization of scandium aluminum nitride (Al1−x Sc x N, x  =  27%) films and discusses surface acoustic wave (SAW) devices based on them. Both AlScN and AlN films were deposited on silicon by sputtering and possessed columnar microstructures with (0 0 0 2) crystal orientation. The AlScN/Si SAW devices showed improved electromechanical coupling coefficients (K 2, ~2%) compared with pure AlN films (<0.5%). The performance of the two types of devices was also investigated and compared, using acoustofluidics as an example. The AlScN/Si SAW devices achieved much lower threshold powers for the acoustic streaming and pumping of liquid droplets, and the acoustic streaming and pumping velocities were 2  ×  and 3  ×  those of the AlN/Si SAW devices, respectively. Mechanical characterization showed that the Young's modulus and hardness of the AlN film decreased significantly when Sc was doped, and this was responsible for the decreased acoustic velocity and resonant frequency, and the increased temperature coefficient of frequency, of the AlScN SAW devices

Flexible surface acoustic wave broadband strain sensors based on ultra-thin flexible glass substrate

Flexible SAW devices based on ZnO piezoelectric thin film deposited on ultra-thin flexible glass were fabricated and their performances as a strain sensor have been investigated. The XRD and AFM characterizations showed that the ZnO layers have good crystal quality and smooth surface. The flexible SAW devices show excellent strain sensitivity which increases from ∼87 to ∼137 Hz/με with the increasing ZnO thickness, and the sensors can withstand strains up to ∼3000 με, 4∼6 times larger than those of SAW strain sensors on rigid substrates. The sensors exhibited remarkable stability up to hundreds of times bending under large strains. The effects of environmental variables (temperature, humidity, UV light) on the sensor performance have been investigated. The temperature has a significant effect on the performance of the SAW strain sensor, while humidity and light have limited effect