Ultrasonic Hot Embossing of polymers is one of the most attractive manufacturing methods of high-quality and complex microparts needed for biological and chemical processes. A little simulation work has been done to study the deformation mechanism and the required load in the Ultrasonic Hot Embossing of polymethyl methacrylate (PMMA). This paper developed a 2D coupled thermo-mechanical finite element model to simulate the forming behavior of the ultrasonic embossing process of PMMA, optimize the mold microfeature corner, and predict the embossing load as well. VDISP ABAQUS subroutine has been used to describe the downward motion of the mold assisted with ultrasonic vibration. The Arbitrary Eulerian-Lagrangian re-meshing technique has been implemented to refine the deformation zone during simulation to avoid divergence due to localized excessive deformation. Embossing load, temperature, stresses, strains, and energy dissipation have been recorded and analyzed. Simulation results revealed that the coupled thermo-mechanical FE Model efficiently captures the deformation behavior and Embossing load. It also proved that a Mold microfeature corner of 20 μm filet radius is recommended to adequately fill out the area around the mold and maintain uniform temperature and strain distributions.

Ultrasonic micro hot embossing (UMHE) is a prominent technique used in numerous sectors to produce micro parts since it is cheaper, faster, and more accurate. Amplitude uniformity is a crucial parameter in UMHE in order to manufacture micro parts with accurate dimensions and high-quality surfaces, even though limited research has been conducted on the uniformity of ultrasonic amplitude at the horn face during the embossing process. This paper presents an experimental and numerical study for designing an ultrasonic transducer and horn tailored to the micro hot embossing of polymer micro parts. A finite element (FE) simulation model combined with the Taguchi method has been developed to optimize the horn geometry and maximum amplitude uniformity. The Taguchi orthogonal array of 25 design runs has been generated and simulated using the developed FE modal analysis model, and then the optimized geometry was used to fabricate the horn. Applied torque and operating time calibrate and evaluate the transducer vibration characteristics. Experimental and simulation results revealed that the fabricated ultrasonic transducer and horn of a straight microfeature has a natural frequency of 28.8 kHz and has an 11 µm average peak-to-peak amplitude with 0.963 amplitude homogeneity along the microfeature face. The achieved frequency separation was greater than 0.85 kHz, whereas the gain ratio was 1.2. The design methodology developed in this paper showed great potential and has been numerically validated for various microfeature shapes across the horn face. Consequently, it can be applied to various ultrasonic applications beyond UMHE.

Microgrids interconnectivity has a significant impact on the performance of interconnected microgrids. This study aims to define the distributed network (DN) optimal interconnection problem to minimize both the undesirable voltage dips and the overall costs through optimal deployment and proportioning of solar facade and rooftop PVs. With the unpredictability of the loads and the PV-captured energy, the capability of these optimizers remains a research issue. Initially, to address the optimal interconnectivity issues of contemporary DNs, this study proposes a novel modified optimization framework. Under the investigated framework, several recent meta-heuristic algorithms (AO, SMA, WHO, PSO) are developed to find the optimal locations for the solar PVs. Secondly, to confirm the geographical independence of the developed framework for improving the DN performance, the hourly meteorological data is utilized to rescale the facade and rooftop PVs at several distinct locations. Furthermore, the ratio between the facade and rooftop solar PVs is determined by techno-economic feasibility analysis. Ultimately, the Spearman and correlation coefficients are used to investigate complementarity and the relationship between the facade and rooftop PVs’ irradiation patterns and capacities. The flexible deployment of PVs on the roof and the facade of the buildings has substantially enhanced the voltage profile of the DN. In response to such enhancement, the techno-economic viability records facade ratio with respect to the rooftop type of (21.5%:78.3%) in Paris, France, compared to (15.9%:84.1%) in Neom, Saudi Arabia. In terms of meeting the objective function and enhancing the performance of the expansive 295-bus system, the WHO optimizer outperforms the other algorithms.

The paper proposes an energy management system, which considers the efficiency of the reversible pump/turbin-e that varies nonlinearly depending on the water flow rate during the pump/turbine modes of operation. A vibration avoidance strategy of the reversible pump hydro storage is developed. A probabilistic approach based on artificial neural networks and Naive-based is used. Through minimizing the levelized Cost of Energy (COE), this study shows the optimal size and reconfiguration of the HMG system as well as purchased/sold energy. Two novel modified optimizers based on the Particle Swarm Optimization (PSO) and the Aquila Optimizer (AO), namely: AO initialized PSO and AO updated PSO are developed. The results via the PSO and AO optimizers are compared in terms of reducing the COE and attaining a low execution time. Based on the results, a COE of 0.22 $/kWh through the developed strategy could be obtained with CO2 emissions of 1974 ton/year against 0.24 $/kWh and 2460 ton/year using the PSO, which saves 24.6% of the yearly CO2 emissions. Furthermore, the vibration avoidance strategy avoids the dead zones and enables the reversible pump/turbine machine to operate at higher efficiencies — both of which are impossible to achieve in the occurrence of vibrations.

The presence of communication networks inside load frequency control loops exposes them to cyber–physical attacks, particularly denial-of-service and deception attacks. Potential cyber–physical attacks on power systems degrade the control performance or even cause instability. This paper proposes a blockchain-based solution against denial-of-service attacks to secure resilient smart systems. A multi-area-based PI-controllers microgrid system is examined. To protect access to the shared blockchain, a proof-of-work private blockchain approach is developed. During denial-of-service attacks, the proof-of-work based blockchain approach safeguards a copy of all data amongst smart grid parts and thus restores the true information. An H∞ control approach is developed to mitigate the uncertainty of the denial-of-service intrusions. Numerical simulations demonstrate the superiority of the proposed blockchain based H∞ controller in comparison to traditional controllers in safeguarding power systems against denial-of-service attacks.

Under earthquake excitations, reinforced concrete (RC) columns could be subjected to lateral drift reversals and a combination of axial forces, bending moments, and torsional effects. This paper investigates the behavior of glass fiber-reinforced polymer (GFRP)-RC columns under seismic-simulated loading, including torsion, which has not been studied previously. Seven large-scale circular GFRP-RC column-footing connections were cast and tested under various combined reversed cyclic loading configurations to examine the effects of torsion-bending moment ratio (tm), transverse reinforcement ratio, and concrete compressive strength. The test results revealed that increasing the tm reduced the lateral load capacity and deformability of the GFRP-RC column, but resulted in a more symmetric torque-twist relationship. Increasing the transverse reinforcement ratio mitigated core damage and provided additional support (for example, spiral turns) for torsion-induced tensile stresses. Moreover, increased concrete compressive strength bolstered torque capacity and torsional stiffness, while, under a tm of 0.4, it resulted in decreased twist capacity. When torsion was present, increasing the concrete compressive strength had an insignificant impact on the bending-shear response, differing from findings for GFRP-RC columns subjected to seismic loading without torsion.

This study presents the results of an investigation into the seismic performance of six large-scale concrete circular columns reinforced with glass fiber–reinforced polymer (GFRP) reinforcement. Among these columns, one underwent concentric reversed cyclic lateral loading, causing bending and shear, while the remaining five columns experienced eccentric cyclic lateral loading, causing additional torsional stresses. The test variables included the torsion-to-bending moment ratio, transverse and longitudinal reinforcement ratios, and concrete compressive strength. The test results indicated that the concurrent cyclic torsion and lateral drift reversals significantly altered the behavior of concrete members in terms of mode of failure, lateral load resistance, drift capacity, and energy dissipation. It was found that adequately confined columns exhibited a notable reduction in concrete core deterioration, thereby preventing the decline in both bending and torsional strength. Furthermore, the paper examined the validity of the North American design provisions predicting the torsional strength of GFRP-reinforced concrete members subjected to combined seismic loading. Amendments to the GFRP tensile stress limits specified in these provisions were introduced, yielding better and safer predictions for the torque capacity of the tested columns.

This study assesses the agronomic and economic advantages of replacing traditional flood irrigation with drip irrigation for sugarcane cultivation in water-scarce Upper Egypt. Confronting severe water shortages and inefficient conventional practices, we conducted a three-year comparative field study assessing crop yields and water use efficiency. The results reveal that drip irrigation improves water-use efficiency by 44% and increases sugarcane yields by 22% relative to flood irrigation, while also elevating net profits by 50%. Drip irrigation demonstrated an average efficiency of 85–90%, compared to 50–60% for flood irrigation. These findings underscore the dual benefits of drip irrigation in addressing water scarcity and enhancing agricultural productivity. The study provides compelling empirical evidence supporting drip irrigation as a sustainable solution for arid regions. To ensure long-term water resource sustainability and food security, we urge policymakers and agricultural stakeholders to prioritize large-scale adoption of drip irrigation systems through targeted investments and policy interventions.

ABSTRACT: One of the problems facing the underground tunnels is lacking enough fresh air for passengers inside the subway. Also, because of the friction of the train with the railways, high heat is generated. So, the use of computational fluid dynamics to

distribute the required fresh air flow at the lowest possible cost is critical for the tunnels. In this research, Computational Fluid Dynamics (CFD) is used to perform 3D modelling and simulation for the tunnel of Cairo Metro Line No. 3. The standard k-e

turbulence model was used in the CFD analysis to simulate the ventilation airflow in a 1075m tunnel length. The simulation reveals that the tunnel airflow rate induced by the speed of the fan is more desirable. Also, the addition of a jet fan causes an eddy current that improving the efficiency of tunnel ventilation, thereby greatly reducing ventilation time, and increasing

efficiency in cases where the diameter of the tunnel equals 15 m, the speed of the fan is 1480 r.p.m, and the air flow rate is 80-

120 m³/s. This led to improve fan speed efficiency and airflow distribution in the tunnel. Similar way of simulation is used for

road tunnel ventilation.