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In this paper, COMSOL multi-physics field commercial software was used to design the simulation model of GaAs nanostructures array (vertical nanoholes, vertical nanowires, inclined nanoholes and inclined nanowires), and the changes of light absorption of these structures in the wavelength range of 200–840 nm were studied. The electric field distribution, carrier distribution and quantum efficiency of nanostructures are calculated and analyzed under certain structural parameters. The results show that the light absorption performance of nanowire structure in the short-wave region is better than that of the nanoholes structure. With a certain inclined angle, the inclined nanowire structure has a stronger light capture ability than the vertical nanowire structure, and the light absorption of nanowire structure has a minimum value at the 550 nm wavelength.

Solar cell development has been largely done by investigating how changes in the structural design of new materials will affect the cell’s performance. Although this process has been used for decades, it can sometimes be slow and expensive. Therefore, a new approach to solar cell development must be taken via simulations and modeling to enhance the cell performance. Simulations and modeling before actual fabrication have the added benefit of avoiding wastage of costly materials and time. This paper reviews the various types of solar cells and discusses the latest developments in the photovoltaic field. It also expounds how modeling solar cells before the developmental phase is beneficial with a focus on COMSOL Multiphysics describing how it is particularly advantageous.

This study investigated fluid flow and forced convective heat transfer in rectangular microchannels with square barriers, as illustrated in Fig. 1. In the first situation, three obstacles were positioned along the microchannel’s top wall. In the second scenario, obstacles were positioned along the microchannel’s bottom wall. In the final example, three square obstacles are placed symmetrically on either side of the microchannel wall. With the help of the Finite Element Method (FEM), we investigate the physicochemical behavior of the microchannel. The development of computer code within COMSOL multiphysics made it possible to simulate heat transport and fluid flow. The results include the implications of the rarefaction effect on fluid flow and heat transmission and decisions regarding the location of barriers and the shape of obstacles in squares. In addition, with the lowest value in skin friction and a lower Nusselt number, the third example, which has barriers on both sides, provides a valuable method for reducing the fluid temperature at the exit of the microchannel. This is because it has barriers on both sides. In the section under “Results and Discussion,” we provide an in-depth analysis of the numerical data derived from the microchannel.

• •Objective: This study aims to numerically investigate forced convective heat transfer in a rectangular channel featuring multiple square obstacles. The simulation employs the FEM to model fluid flow and temperature distribution.
• •Geometry and complexity: The channel geometry incorporates square obstacles, introducing geometric complexity. The FEM is chosen for its capability to handle intricate geometries accurately.

Vibrations can be a good source of energy and can be harvested and utilized by simple design and fabrication using the MEMS technology. Energy harvesting provides unending sources of energy for low-power electronics devices where the use of batteries is not feasible. Piezoelectric energy harvesters are widely considered because of their compact design, compatibility to MEMS devices and ability to respond to a wide range of frequencies freely available in the environment. In this project, a rectangular model for cantilever-based piezoelectric energy harvester is proposed with different designs like two layer, two layer with proof mass, four layer and four layer with proof mass designed with dimensions as 50$\mu$m$\times$50$\mu$m$\times$1$\mu$m for each layer using COMSOL Multiphysics 5.0. Simulation results were obtained using silicon as substrate, aluminium as electrodes and PZT-5H and ZnO as piezoelectric materials and the respective stress and voltages were obtained by applying a force acting on foot, train, roller coaster and a general value of 10N/m² on top of the cantilever. The effects of varying geometrical dimensions of the device were also investigated.

Perovskite solar cells have recently been considered to be an auspicious candidate for the advancement of future photovoltaic research. A power conversion efficiency (PCE) as high as 22% has been reported to be reached, which can be obtained through an inexpensive and high-throughput solution process. Modeling and simulation of these cells can provide deep insights into their fundamental mechanism of performance. In this paper, two different perovskite solar cells are designed by using COMSOL Multiphysics to optimize the thickness of each layer and the overall thickness of the cell. Electric potential, electron and hole concentrations, generation rate, open-circuit voltage, short-circuit current and the output power were calculated. Finally, PCEs of 20.7% and 26.1% were predicted. Afterwards, according to the simulation results, the role of the hole transport layer (HTL) was investigated and the optimum thickness of the perovskite was measured to be 200nm for both cells. Therefore, the spin coating settings are selected so that a coating with this thickness for cell 1 is deposited. In order to compare the performance of HTM layer, solar cells with a Spiro-OMeTAD HTM and without the HTM layer in their structure were fabricated. According to the obtained photovoltaic properties, the solar cell made with Spiro-OMeTAD has a more favorable open-circuit voltage ($V_{\mathrm{\text{OC}}}$), short-circuit current density ($J_{\mathrm{\text{SC}}}$), fill factor (FF) and PCE compared to the cell without the HTM layer. Also, hysteresis depends strongly on the perovskite grain size, because large average grain size will lead to an increase in the grain’s contact surface area and a decrease in the density of grain boundaries. Finally, according to the results, it was concluded that, in the presence of a hole transport layer, ion transfer was better and ion accumulation was less intense, and therefore, the hysteresis decreases.

Due to advancements in Micro-Electro-Mechanical Systems (MEMS) fabrication technologies, researchers are incorporating numerous innovations in the design of capacitive pressure sensors (CPS). This work aims to present a novel CPS design using a plano-convex substrate to enhance the capacitance and sensitivity. Diaphragm deflection occurs due to its elastic property when pressure is applied to the diaphragm. This deflection reduces the distance between the diaphragm and substrate, thereby remarkably increasing capacitance. The Plano-Convex design offers added advantages of increased contact area between the diaphragm and substrate under applied pressure, hence significantly enhancing sensor sensitivity and range. More efficient and miniaturized CPSs are in high demand in medical instrumentation, aerospace, aviation, power plants and automotive industries. This work presents all the required mathematical calculations, modeling and simulations to support the proposed design. The diaphragm deflection simulation concerning pressure is conducted using COMSOL Multiphysics, while MATLAB is employed for analytical simulations related to changes in capacitance and capacitive sensitivity.

In this research work, the M-shaped cantilever piezoelectric energy harvester is modeled and optimized using advanced artificial intelligence algorithms. The proposed harvester adopts a single structure geometrical configuration in which two secondary beams are being connected to the principal bimorph. Finite element analysis is carried out on COMSOL Multiphysics to analyze the efficiency of the proposed energy harvester. The influence of frequency, load resistance, and acceleration on the electrical performance of the harvester is numerically investigated to enhance the bandwidth of the piezoelectric vibrational energy harvester. Numerical analysis is also utilized to obtain the iterative dataset for the training of the artificial neural network. Furthermore, a genetic multi-objective optimization approach is implemented on the trained artificial neural network to obtain the optimal parameters for the proposed energy harvester. It is observed that optimization using modern artificial intelligence approaches implies nonlinearities of the system and therefore, machine learning-based optimization has shown more convincing results, as compared to the traditional statistical methods. Results revealed the maximum output values for the voltage and electrical power are 15.34 V and 4.77 mW at 51.19 Hz, 28.09 k$\mathrm{\Omega }$, and 3.49 g optimal design input parameters. Based on the outcomes, it is recommended to utilize this reliable harvester in low-power micro-devices, electromechanical systems, and smart wearable devices.

Infrared (IR) heating is often used for the treatment of liquid and solid foods. IR treatment is known to enhance their shelf life by reducing moisture content and inactivating the microorganisms. Mung bean (a type of pulse from India) is a short season crop; suffers maximum storage loss when compared to other legume grains. The losses are due to moisture and temperature movements. Drying of grains is an important post-harvest operation. IR drying is advantageous over the conventional drying methods. In this paper, the drying of mung bean is considered. An experimental setup is developed to obtain the required moisture and temperature profiles. The equivalent model is simulated using COMSOL multiphysics software and the percentage error between the experimental and simulated models is calculated. Results of numerical implementation are presented and possible further extensions are identified.

The radiated acoustic waves from impact pile driving produce high noise level into the water which may cause damage to marine mammals living close to the offshore construction location. In this paper, a linear, axisymmetric finite element (FE) model is applied to predict pile driving noise in the water. Measurement from bottom-mounted hydrophone deployed at a site 230 m from the source is used to validate the model results. The comparisons between model results and measurement, such as structure modal analysis, sound exposure level at different pile penetration and unweighted one-third octave band level, are presented and show useful predictions of noise level from the model. Furthermore, a time domain case is demonstrated to show Mach wave associated with the radial deformation of the pile and supersonic speed. Finally, analysis of variance (ANOVA) and linear regression are made after verifying the model prediction. The ANOVA results identifies some significant parameters on pile driving noise and the empirical equation from linear regression represents the noise level from pile driving impact at close range. These are possible metrics on offshore wind farm environment assessment in Taiwan.