Highly Sensitive Flexible Modulus Sensor for Softness Perception and Clinical Application

The wearable sensors for softness measuring are emerging as a solution of softness perception, which is an intrinsic function of human skin, for electronic skin and human-machine interaction. However, these wearable sensors suffer from a key challenge: the modulus of an object can not be characterized directly, which originates from the complicated transduction mechanism. To address this key challenge, we developed a flexible and wearable modulus sensor that can simultaneously measure the pressure and modulus without mutual interference. The modulus sensing was realized by merging the electrostatic capacitance response from the pressure sensor and the ionic capacitance response from the indentation sensor. Via the optimized structure, our sensor exhibits high modulus sensitivity of 1.9 × 102 in 0.06 MPa, a fast dynamic response time of 100 ms, and high mechanical robustness for over 2500 cycles. We also integrated the sensor onto a prosthetic hand and surgical probe to demonstrate its capability for pressure and modulus sensing. This work provides a new strategy for modulus measurement, which has great potential in softness sensing and medical application.

Bacteria Cell Hydrophobicity and Interfacial Properties Relationships: A New MEOR Approach

For microbial enhanced oil recovery (MEOR), different mechanisms have been introduced. In some of these papers, the phenomena and mechanisms related to biosurfactants produced by certain microorganisms were discussed, while others studied the direct impacts of the properties of microorganisms on the related mechanisms. However, there are only very few papers dealing with the direct impacts of microorganisms on interfacial properties. In the present work, the interfacial properties of three bacteria MJ02 (Bacillus Subtilis type), MJ03 (Pseudomonas Aeruginosa type), and RAG1 (Acinetobacter Calcoaceticus type) with the hydrophobicity factors 2, 34, and 79% were studied, along with their direct impact on the water/heptane interfacial tension (IFT), dilational interfacial visco-elasticity, and emulsion stability. A relationship between the adsorption dynamics and IFT reduction with the hydrophobicity of the bacteria cells is found. The cells with highest hydrophobicity (79%) exhibit a very fast dynamic of adsorption and lead to relatively large interfacial elasticity values at short adsorption time. The maximum elasticity values (at the studied frequencies) are observed for bacteria cells with the intermediate hydrophobicity factor (34%); however, at longer adsorption times. The emulsification studies show that among the three bacteria, just RAG1 provides a good capability to stabilize crude oil in brine emulsions, which correlates with the observed fast dynamics of adsorption and high elasticity values at short times. The salinity of the aqueous phase is also discussed as an important factor for the emulsion formation and stabilization.

Fault Tolerant Control of PMSM Three-Phase Four-Switch Inverter

Permanent Magnet Synchronous Motor (Permanent Magnet Synchronous Motor, hereinafter referred to as PMSM) has the characteristics of small size, high efficiency, high power density and fast dynamic response, etc., and more and more applications in the transportation industry. This also has higher and higher requirements for the reliability and security of PMSM drivers. In this paper, the fault tolerant control strategy of PMSM based on three phase four switch inverter is proposed based on vector control and the simulation verification is carried out.