Nonlinear Parameter Identification of a Resonant Electrostatic MEMS Actuator.

We experimentally investigate the primary superharmonic of order two and subharmonic of order one-half resonances of an electrostatic MEMS actuator under direct excitation. We identify the parameters of a one degree of freedom (1-DOF) generalized Duffing oscillator model representing it. The experiments were conducted in soft vacuum to reduce squeeze-film damping, and the actuator response was measured optically using a laser vibrometer. The predictions of the identified model were found to be in close agreement with the experimental results. We also identified the noise spectral density of process (actuation voltage) and measurement noise.

The influence of potassium nanoparticles as a foliar fertilizer on onion growth, production, chemical content, and DNA fingerprint.

Potassium is an important macro-fertilizer for plant growth but can be lost from the soil after application via irrigation. Slow-release nano-fertilizers can achieve sustainable crop cultivation and production, so this study evaluated the influence of potassium nanoparticles (K-NPs) with various concentrations (0, 50, 100, and 200 mg/l) on onion development, production, pigments, chemical content, and DNA fingerprint during two sequential agriculture seasons in 2021 and 2022 at a private farm in Zagazig, Sharkia Governorate, Egypt. Spraying onion plants with K-NPs (200 mg/l) significantly improved the vegetative characteristics of onion plant growth and production, as well as increasing the plant pigments and the content of carbohydrate, oil, total indole, and phosphorus in onion bulbs. Similarly, 50 mg/l of K-NPs considerably increased the content of nitrogen, potassium, protein, antioxidant activity, and phenols in the onion bulbs. The content of total flavonoids and anthocyanin was increased with 100 mg/l of K-NPs. In conclusion, the foliar application of K-NPs improves the onion plant yield and quality and can achieve agricultural sustainability.

A Generalized Model for Curved Nanobeams Incorporating Surface Energy.

This work presents a comprehensive model for nanobeams, incorporating beam curvature and surface energy. Gurtin-Murdoch surface stress theory is used, in conjunction with Euler-Bernoulli beam theory, to model the beams and take surface energy effects into consideration. The model was validated by contrasting its outcomes with experimental data published in the literature on the static bending of fixed-fixed and fixed-free nanobeams. The outcomes demonstrated that surface stress alters the stiffness of both fixed-fixed and fixed-free nanobeams with different behaviors in each case.

Nano Groove and Prism-Structured Triboelectric Nanogenerators.

Enhancing the output power of triboelectric nanogenerators (TENGs) requires the creation of micro or nano-features on polymeric triboelectric surfaces to increase the TENGs' effective contact area and, therefore, output power. We deploy a novel bench-top fabrication method called dynamic Scanning Probe Lithography (d-SPL) to fabricate massive arrays of uniform 1 cm long and 2.5 µm wide nano-features comprising a 600 nm deep groove (NG) and a 600 nm high triangular prism (NTP). The method creates both features simultaneously in the polymeric surface, thereby doubling the structured surface area. Six thousand pairs of NGs and NTPs were patterned on a 6×5 cm2 PMMA substrate. It was then used as a mold to structure the surface of a 200 µm thick Polydimethylsiloxane (PDMS) layer. We show that the output power of the nano-structured TENG is significantly more than that of a TENG using flat PDMS films, at 12.2 mW compared to 2.2 mW, under the same operating conditions (a base acceleration amplitude of 0.8 g).

Mitigation and damage to the built environment - v.2

A practical simplified model methodology assessment of vulnerability and impact of failure and disruption for water supply system is presented in this paper. The model methodology consists of four major steps: 1)System Inventory, involving the determination of key system component attributes, such as location, materials of construction, seismic vulnerability, etc 2)Identify Seismic Hazards, involving the identification of active earthquake faults, potentially liquefiable soils, and similar earthquake hazards 3)Estimation of Impact ofhazard on System Component, involving determination of key component potential damage and reduced funtionality, due to identified seismic hazards, 4)System Analysis, involving estimation of losses due to direct damage to components and estimation of reduced system funtionality, in terms of residual capacity and time-to-restoration