Micro and Nanosystems - Volume 14, Issue 4, 2022

Background: Due to their size, microelectromechanical systems (MEMS) display performance indices affected by uncertainties linked to the mechanical properties and to the geometry of the films constituting their movable parts. Objective: In this perspective, a recently proposed multiscale and hybrid solution for uncertainty quantification is discussed. Methods: The proposed method is based on the (deep) learning of the morphology-affected elasticity of the polycrystalline films and of the microfabrication-induced defective geometry of the devices. The results at the material and at the device levels are linked through a reduced-order representation of the response of the entire device to the external stimuli, foreseen to finally feed a Monte Carlo uncertainty quantification engine. Results: Preliminary results relevant to a single-axis resonant Lorentz force micro-magnetometer have shown a noteworthy capability of the proposed multiscale deep learning method to account for the mentioned uncertainty sources at the microscale. Conclusion: A promising two-scale deep learning approach has been proposed for polysilicon MEMS sensors to account for both materials- and geometry-governed uncertainties and to properly describe the scale-dependent response of MEMS devices.

Because of major developments in fundamental research and industrial applications, graphene's mass and low-cost production have become a vital step toward its real-world uses. Graphene, a one-atom-thick carbon crystal with a unique set of physical and chemical properties comprising extreme mechanical behaviour with excellent electrical and thermal conductivity, is emerging as a serious contender to replace many traditional materials in a variety of applications. Graphene has the potential to improve the performance, functionality, and durability of a broad spectrum of applications, but its commercialization will require more study. Applications and emerging techniques for the production of graphene have been investigated in this study. To increase the use of graphene, its current limitations must be solved expeditiously to improve its performance. In terms of applications, graphene's advantages have expanded its use in both electroanalytical and electrochemical sensors. This review paper highlights the most important experimental successes in graphene material manufacturing, as well as its changing characteristics in connection to smart applications. We explore how graphene may be successfully integrated directly into devices, enabling a wide range of applications such as transparent electrodes, photovoltaics, thermoelectricity, 3D printing, and applications in biomedical and bioimaging devices. Graphene's prospects are also explored and discussed.

Background: Complete Ternary Adder is the prime building block for Ternary Carry Save Adder (TCSA) and acts as a critical deciding factor to optimize the overall speed-power performance for many complex ternary computing like ternary multiplications. Objective: This work proposes a new idea for high-speed complete Ternary Adder design with reduced Power-Delay-Product (PDP) using PTL (Pass Transistor Logic) based novel 3:1 Ternary Multiplexer (T-MUX) for efficient ternary computing. Methods: In the proposed approach, a novel 3:1 T-MUX with conventional E-MOS (Enhancementtype Metal Oxide Semiconductor) transistor is designed first. The Novel Select Unit (SU) and Control Unit (CU) are the prime building blocks of the proposed T-MUX circuit, which are discussed in detail. The 3:1 T-MUX is exploited next to achieve the proposed high-speed, low-PDP Ternary Half and Full Adder operation. The complete adder circuit is designed and optimized based on BSIM4 device parameters using 32nm standard CMOS technology with 1.0V supply rail at 27°C temperature. Trit values “0”, “1” and “2” are represented with 0V, 0.5V and 1.0V respectively. Extensive T-Spice simulation with all possible test patterns using PWL (Piece Wise Linear) input source validates the proposed circuit. The evaluated speed-power result of the proposed TFA is then compared with the most recent competitive study to set a benchmark. Results: The proposed complete TFA offers 68.9% and 82.5% reduction in propagation delay along with 27.7% and 31.6% Power-Delay-Product (PDP) reduction compared to the most recent competitive complete TFA Design-1 and Design-2, respectively. Discussion: As per the study, the proposed idea can be a good selection to produce fast ternary addition along with reduced Power-Delay-Product (PDP). Conclusion: The proposed complete TFA can be utilized effectively as Ternary Carry Save Adder (TCSA) for fast, low-PDP ternary multiplication as well as for other computation-intensive applications.

A transdermal patch is a topically applied adhesive patch that delivers a medication dose directly into the blood. The patch allows for the safe delivery of a drug to the targeted site, ideally by a permeable layer covering a reservoir of the drug by melting small patches of drug embedded in the adhesive, which is one benefit of transdermal drug delivery over most types of pharmaceutical deliveries, including oral, topical, intramuscular, intravenous, and several others. This can also help heal a damaged body part, improving patient compliance, treatment efficacy, and dose frequency while minimizing the side effects. This review covers the production, methods of evaluation, quality, use of penetration enhancers, and pros and downsides of transdermal patches, as well as the benefits of essential oil as a penetration enhancer. Compared to chemical enhancers, essential oils have shown the ability to break down the stratum corneum layer, allowing drugs to penetrate deeper into the skin. Essential oils are excellent penetration enhancers for the skin. These penetration enhancers are cost-effective, biocompatible, readily available, non-toxic, chemically modifiable, and possibly biodegradable. In this review, attention has been paid to the formulation and evaluation of transdermal patches with the help of SNEDDS (self-nano-emulsifying drug delivery systems) using essential oil as a penetration enhancer, and their future prospects.

Background: Correct modeling of squeeze-film damping (SFD) is an important consideration in the design of high-Q microresonators. In 2002, using the molecular dynamics (MD) approach, Bao et al. developed an analytical MD model for the evaluation of the SFD of a parallel-plate device in the free molecular regime. Their model was based on the energy exchange between the oscillating plate and gas molecules. Bao’s model is now widely used in microsystem design. However, Bao’s model cannot reduce to the air damping model in free space and is unsuitable for flexible microbeams. Objective: This paper first presents a more accurate analytical model for the evaluation of the SFD of the parallel plate. Then the present analytical model is extended to model the SFD of flexible microbeams with deformed shapes. Methods: This paper is based on the momentum transfer between the vibration plate and gas molecules. Results: The analytical results of the present model have shown a good agreement with the available experimental results. Conclusion: The limitations in the previous model are overcome.

Background: As the technology node scales down to a deep sub-micron regime, the design of static random-access memory (SRAM) cell becomes a critical issue because of increased leakage current components. These leakage current components prevent the designing of a low-power processor as a large portion of the processor power is consumed by the memory part. Objective: In this paper, an SRAM cell is designed based on the ON/OFF logic (ONOFIC) approach. Static noise margin (SNM) of the cell for the different states are calculated and evaluated by using the butterfly as well as noise (N) curves with the help of Cadence tools at 45 nm technology node. Methods: ONOFIC approach reduces the leakage current components, which makes a low power memory cell. A performance comparison is made between the conventional six-transistor (6T) SRAM cell and memory cell using the ONOFIC approach. Results: Low value of power delay product (PDP) is the outcome of the ONOFIC approach as compared to conventional cells. ONOFIC approach decreases PDP by 99.99% in case of hold state. Conclusion: ONOFIC approach improves the different performance metrics for the different states of the SRAM cell.

Background: The state estimation (SE) process in power systems estimates bus voltage magnitude and phase angles vital for operating the system securely and reliably. The power systems state estimation problem has been extensively solved through a weighted least squares (WLS) based static approach that fails to track the system dynamics. Furthermore, those approaches are not inherently robust against outliers, yielding a separate bad data processing (BDP) technique. Popular Dynamic state estimation (DSE) schemes which mainly employ nonlinear Kalman filters like Extended Kalman Filter (EKF) and Unscented Kalman Filter (UKF), also suffer from providing a reasonable estimation of states in the presence of bad data. Although several generalized maximum (GM) likelihood- based DSE approaches are robust against outliers, they are mainly based on nonlinear Kalman filters, which yield an iterative process. Therefore, this article focuses on developing a robust DSE approach that gives a good estimation of states against outliers in a single iteration. Objective: This article aims to propose a robust hybrid non-iterative DSE approach that gives robust SE results in the presence of bad data. Methods: The proposed novel robust hybrid DSE (NRHDSE) approach combines the robust Mestimation with the original novel hybrid DSE (NHDSE) approach. The proposed scheme implements a suitable linear relationship between integrated hybrid measurements and complex states. The proposed method uses a linear measurement model and thus employs an optimal linear Kalman filter to correct or estimate states. Results: The efficacy of the proposed approach has been demonstrated by applying it on IEEE 57, 118 bus test systems and one more extensive 246 Indian utility bus system, namely, Northern Regional Power Grid (NRPG), and after that comparing it with the original NHDSE, and DSE methods based on traditional EKF and M-estimation based robust version of EKF (REKF). The simulation result demonstrates the superiority of the proposed approach. Conclusion: Obtained results clearly show the superiority of the proposed approach.

Background: Utilizing mirror movement precisely, one can undoubtedly make a diverse way for light. The movable mirror can be placed in the path of an optical tree net to perform different operations. Objective: In this paper, we have performed different logic, arithmetic, and one-bit data comparison operations using mechanical movable mirrors. Methods: Using two controls with three movable mirrors and two fixed mirrors, we can perform four basic logic operations. Then using these four basic operations, we can design sixteen different logic operations, a half adder, and one-bit data comparison operations. Results: Because of an adaptable mirror arranging and course component, expansion incidents can be decreased to an incredibly low level. The necessary voltage is under 0.5 V. The power utilization is about 3.5 mW for an exchanging component. Conclusion: Moreover, this plan is extremely straightforward in a sense and designed using linear optical materials. The principle of operation of this circuit is based on the reflection of light from MEMS-based optical switches.

Background: Among the parameters that play an important role in describing the performance of many devices is carrier mobility which is a criterion for the easy movement in semiconductor crystals. Objective: The effect of carrier mobility on the performance characteristics of InGaN quantum well vertical-cavity surface-emitting laser was analytically investigated. Methods: By solving the Poisson’s equation, current density equation, charge concentration continuity equation and carrier and photon rate equations, the variation of current density and carrier density with respect to the position and time and the effects of carrier mobility and temperature on these parameters were investigated. Furthermore, the effect of mobility on the variation of output power versus the injection current and on the time variation of photon and carrier density and the output power was investigated. Results: By increasing the carrier mobility, the threshold current is reduced and the output power is increased. In studying the effect of temperature on the desired parameters, the variation of carrier density with respect to time and position was affected by the temperature change. This phenomenon is due to the dependence of these parameters on the diffusion coefficients and consequently on the mobility of the carriers and the dependence of mobility on temperature. Conclusion: The output power increased, and the time delay in accruing the laser decreased. Consequently, the carrier recombination increased, further resulting in a rapid laser operation.

Background: Proton exchange membrane is an art of PEM fuel cells, developing active materials with robust structure and high proton conductivity has attained huge attention in recent decades amongst researchers. Aims/Objectives: Here, we have developed a novel approach to prepare a siliceous mesoporous heteropoly acid with high stability in polar media and high proton conductivity to be utilized as proton exchange membrane. Methods: A highly stable mesoporous siliceous phosphomolybdic acid has been synthesized via a simple self-assembly between Phosphomolybdic Acid (PMA), the polymeric surfactant, and the silica precursor stabilized by KCl molecules as a proton conducting material for proton exchange membrane application. Results: As prepared, siliceous mesoporous phosphomolybdic acids (mPMA-Si) show a high surface area with a highly crystalline structure; however, the crystallinity is reduced by increasing the silica content. Further analysis proved the Keggin structure remains intact in final materials. mPMA-8 Si shows the highest performance among all the materials studied with proton conductivity of 0.263 S.cm-1 at 70 °C. Conclusion: As prepared, mPMA-xSi has shown a very high proton conductivity in a range of temperatures, making them a promising material for proton exchange membrane.