Design and evaluation of a micro resonator structure as a biosensor for droplet analysis with a standard fabrication method

Purpose In this work, the sensing and actuating elements are designed with interdigitated capacitors away from the sensitive element on which the droplet is placed. This pattern helps to prevent interference of electrical elements with the droplet. Choosing shear resonance mode at this proposed structure minimizes the damping effect of droplet touch by the resonator structure. The glass-based standard fabrication method of the proposed biosensor is presented exactly. Design/methodology/approach Mechanical resonator sensors are extremely limited because of the high damping factor and the high electrical conductivity in the aqueous environment. In this work, a molecule detector biosensor is proposed for droplet analysis, which is possible to fabricate using micro-electro-mechanical systems (MEMS) technology. By electromechanical coupling of resonators as a mechanical resonator structure, a standing mechanical wave is formed at this structure by electrostatic actuating elements. Findings In this paper, a mechanical resonator structure as a biosensor is proposed for micro-droplet analysis that can be fabricated by MEMS technology. It is designed at a lower cost fabrication method using electrostatic technology and interdigitated capacitors. The response of the biosensor displacement frequency at the resonance frequency of the desired mode is reasonable for measuring the capacitive changes of its output. The mass sensitivity of the proposed biosensor is in the range of 1 ng, and it has a large sensitive area for capturing target molecules. Originality/value To evaluate the quality of the proposed design, the stimulated analysis is conducted by COMSOL and results are presented.

Real-Time Monitoring of HT-PEMFC

During the electrochemical reaction of a high temperature proton exchange membrane fuel cell (HT-PEMFC), (in this paper HT-PEMFC means operating in the range of 120 to 200 °C) the inhomogeneity of temperature, flow rate, and pressure in the interior is likely to cause the reduction of ion conductivity or thermal stability weight loss of proton exchange membrane materials, and it is additionally likely to cause uneven fuel distribution, thereby affecting the working performance and service life of the HT-PEMFC. This study used micro-electro-mechanical systems (MEMS) technology to develop a flexible three-in-one microsensor which is resistant to high temperature electrochemical environments; we selected appropriate materials and process parameters to protect the microsensor from failure or damage under long-term tests. The proposed method can monitor the local temperature, flow rate, and pressure distribution in HT-PEMFC in real time.

Actively MEMS-Based Tunable Metamaterials for Advanced and Emerging Applications

In recent years, tunable metamaterials have attracted intensive research interest due to their outstanding characteristics, which are dependent on the geometrical dimensions rather than the material composition of the nanostructure. Among tuning approaches, micro-electro-mechanical systems (MEMS) is a well-known technology that mechanically reconfigures the metamaterial unit cells. In this study, the development of MEMS-based metamaterial is reviewed and analyzed based on several types of actuators, including electrothermal, electrostatic, electromagnetic, and stretching actuation mechanisms. The moveable displacement and driving power are the key factors in evaluating the performance of actuators. Therefore, a comparison of actuating methods is offered as a basic guideline for selecting micro-actuators integrated with metamaterial. Additionally, by exploiting electro-mechanical inputs, MEMS-based metamaterials make possible the manipulation of incident electromagnetic waves, including amplitude, frequency, phase, and the polarization state, which enables many implementations of potential applications in optics. In particular, two typical applications of MEMS-based tunable metamaterials are reviewed, i.e., logic operation and sensing. These integrations of MEMS with metamaterial provide a novel route for the enhancement of conventional optical devices and exhibit great potentials in innovative applications, such as intelligent optical networks, invisibility cloaks, photonic signal processing, and so on.

High-Flexibility Control of Structured Light with Combined Adaptive Optical Systems

Combining the specific advantages of high-resolution liquid-crystal-on-silicon spatial light modulators (LCoS-SLMs) and reflective or refractive micro-electro-mechanical systems (MEMS) presents new prospects for the generation of structured light fields. In particular, adaptive self-apodization schemes can significantly reduce diffraction by low-loss spatial filtering. The concept enables one to realize low-dispersion shaping of nondiffracting femtosecond wavepackets and to temporally switch, modulate or deflect spatially structured beams. Adaptive diffraction management by structured illumination is demonstrated for piezo-based and thermally actuated axicons, spiral phase plates (SPPs) and Fresnel bi-mirrors. Improved non-collinear autocorrelation with angular-tunable Fresnel-bi-mirrors via self-apodized illumination and phase contrast of an SLM is proposed. An extension of the recently introduced nondiffractive Talbot effect to a tunable configuration by combining an SLM and a fluid lens is reported. Experimental results for hexagonal as well as orthogonal array beams are presented.

Utilização de MEMS((Micro-Electro-Mechanical Systems – sistemas microeletromecânico) para aplicações de circuitos de baixo custo de movimentação e sensoriamento

Com o avanço da tecnologia os processos de fabricação de microcomponentes dentro de um circuito integrado (CIs) permitiram a construção de micro estruturas mecânicos como sensores e atuadores comumente chamadas de MEMS (electro-mechanical systems – sistemas eletromecânicos) com tamanho na ordem de 0,001 mm e podendo ser compostos de diversos materiais como silicone, cerâmica, polímeros e metais estes sensores estão revolucionando o mercado com diversas aplicações na área de entretenimento, indústria, medicina, automobilístico e aeroespacial dentre outros, que anteriormente era muito limitado devido ao custo e tamanho dos dispositivos. Dentre esses dispositivos serão abordado os sensores de Unidade de Medição Inercial (IMU) com foco no sensoriamento para unidades de automação e robótica.

Novel Fabrication Technology for Clamped Micron-Thick Titanium Diaphragms Used for the Packaging of an Implantable MEMS Acoustic Transducer

Micro-Electro-Mechanical Systems (MEMS) acoustic transducers are highly sophisticated devices with high sensing performance, small size, and low power consumption. To be applied in an implantable medical device, they require a customized packaging solution with a protecting shell, usually made from titanium (Ti), to fulfill biocompatibility and hermeticity requirements. To allow acoustic sound to be transferred between the surroundings and the hermetically sealed MEMS transducer, a compliant diaphragm element needs to be integrated into the protecting enclosure. In this paper, we present a novel fabrication technology for clamped micron-thick Ti diaphragms that can be applied on arbitrary 3D substrate geometry and hence directly integrated into the packaging structure. Stiffness measurements on various diaphragm samples illustrate that the technology enables a significant reduction of residual stress in the diaphragm developed during its deposition on a polymer sacrificial material.

Optimization and prediction of engine block vibration using micro-electro-mechanical systems capacitive accelerometer, fueled with diesel-bioethanol (water-hyacinth) blends by response surface methodology and artificial neural network

The current investigation is focused on the vibration signals analysis for health status diagnosis of the single-cylinder diesel engine fueled with bioethanol diesel mixture. The water hyacinth (WH) plants (Eichhornia crassipes) are used as raw materials for bioethanol production. The bio-ethanol obtained from WH has been mixed with diesel fuel (WBED) to various extent. Systematically designed experiments were conducted with different working parameters like load, fuel injection pressure (FIP), and compression ratio (CR) in a diesel engine. The Micro-Electro-Mechanical Systems (MEMS) capacitive accelerometer was used to get vibration signals from the engine while operating with blended fuels. The obtained experimental vibrations data have been used to predict the engine vibration by using Response Surface Methodology (RSM) technique and Artificial Neural Network (ANN). The experimental results have been compared with RSM and ANN prediction results. From results, it is elicited that the acceleration declines with the increase in load and CR. At all tested blends, FIP produces a significant effect on the engine block vibration. Among all blends, WBED 5 and WBED 10 produce less vibration as compared to other diesel bioethanol blends. At optimized operating condition the engine block vibration for WBED 5; the experimental acceleration is 0.016962 m/s2 and the predicted acceleration by RSM and ANN is 0.016182 m/s2 and 0.0166 m/s2, respectively. For WBED 10, the acceleration is 0.0172604 m/s2 and the predicted acceleration by RSM and ANN 0.016207 m/s2 0.017 m/s2, respectively, has been found.

Theoretical and Experimental Analysis of Surface Roughness and Adhesion Forces of MEMS Surfaces Using a Novel Method for Making a Compound Sputtering Target

Achieving a compound thin film with uniform thickness and high purity has always been a challenge in the applications concerning micro electro mechanical systems (MEMS). Controlling the adhesion force in micro/nanoscale is also critical. In the present study, a novel method for making a sputtering compound target is proposed for coating Ag–Au thin films with thicknesses of 120 and 500 nm on silicon substrates. The surface topography and adhesion forces of the samples were obtained using atomic force microscope (AFM). Rabinovich and Rumpf models were utilized to measure the adhesion force and compare the results with the obtained experimental values. It was found that the layer with a thickness of 500 nm has a lower adhesion force than the one with 120 nm thickness. The results further indicated that due to surface asperity radius, the adhesion achieved from the Rabinovich model was closer to the experimental values. This novel method for making a compound sputtering target has led to a lower adhesion force which can be useful for coating microgripper surfaces.

Risk Evaluation and Warning Threshold of Unstable Slope Using Tilting Sensor Array

Slope monitoring and early warning systems (EWS) are a promising approach toward mitigating landslide-induced disasters. Many large-scale sediment disasters result in the destruction of infrastructure and loss of human life. The mitigation of vulnerability to slope and landslide hazards will benefit significantly from early warning alerts. The authors have been developing monitoring technology that uses a Micro Electro Mechanical Systems (MEMS) tilt sensor array that detects the precursory movement of vulnerable slopes and informs the issuance of emergency caution and warning alerts. In this regard, the determination of alarm thresholds is very important. Although previous studies have investigated the recording of threshold values by an extensometer which installation of an extensometer at appropriate sites is also difficult. The authors prefer tilt sensors and have proposed a novel threshold for the tilt angle, which was validated in this study. This threshold has an interesting similarity to previously reported viscous models. Additionally, multi-point monitoring has recently emerged and allows for many sensors to be deployed at vulnerable slopes without disregarding the slope’s precursory local behaviour. With this new technology, the detailed spatial and temporal variation of the behaviour of vulnerable slopes can be determined as the displacement proceeds toward failure.

Acoustic MEMS Transducers: Look Ahead of the Bit and Geopressure Monitoring

This paper describes the design and implementation of Acoustic Micro Electro Mechanical Systems (hereinafter referred to asA-MEMS)working in fluid-coupling mode for HP/HT specifications relevant to downhole applications such as drilling, well and reservoir monitoring. Many cutting edges applications ofA-MEMS in Oil & Gas industry are envisaged. The current work refers to the case study of a "Look Ahead of the Bit"/geopressure monitoring technique (hereinafter referred to asPPM) developed by the authors. A–MEMS with magnetic shuttle transducers have been designed so that they are not affected by environmental pressure like piezoelectric devices commonly used in MWD commercial sonic tools, which are impaired by volumetric shrinking/expansion working principle. This performance is also achieved by embedding an environmental pressure compensator tuned in the whole working bandwidth to grant pressure balance even with oscillatory motion at sonic frequencies (up to 5 kHz). Transmitter acoustic power and receiver sensitivity have been optimized in a bandwidth between 500 and 3500 Hz. A couple of A–MEMS prototypes have been built and successfully tested by using an oil filled pressure vessel at downhole T–P conditions (200 °C, 700bar) and an ad-hoc measurement setup including force, displacement, temperature sensors, transmitter (TX) driver, receiver (RX) lock-in amplifier and anacquisition system. Moreover, modal analysis at typical drilling conditions has been carried out by Stewart platform. Shock up to 1000 g and random vibrations up to 12 g RMS in 5 ÷400 Hz bandwidth have been tested. A–MEMS performance have turned out to be consistent with theoretical model predictions andhave exhibited robustness to T P variations and applied structural stress. PPM method has been validated through a triaxial compression cell in a rock mechanics laboratory, implementing a lab scale scenario with a cap rock located above a permeable rock, undergoing all geopressures of interest. However, piezo transducers used in the experiment underwent a significant failure/damage rate along with performance degrading at pressure increasing. These observations confirmed and motivated the need for A-MEMS technology development in downhole applications.