## 2 Materials and Methods
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Nanoparticles** & **Density (g/cm\({}^{3}\))** & **Melting Point (\({}^{\circ}\)C)** & **Particle Size (nm)** \\ \hline Graphite nanoplates (GNP) & 2.267 & 3650 & 5–10 \\ \hline Zirconium Oxide (ZrO\({}_{2}\)) & 5.680 & 2715 & 20–50 \\ \hline Bamboo Charcoal (BC) & 0.690 & 1200 & 20–50 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Details of nanoparticles reinforced in CO-based flexible polyurethane foam. The electronic assembly's actual shielding effectiveness is assessed using the open field or free space method. The radiated emissions that run away from the completed product are measured using this method. The EMI SE testing parameters include a typical network analyzer with model number N5230A PNA-L. It has a dynamic range of 108 dB and operates from 10 MHz-50 GHz. Waveguide measurements and OSL/TLL calibration are also available. The operational voltages for the experiments were +5 V and 15 V. Specimens were examined in the transmitter range at a frequency range of 8-12 GHz with a phase resolution of 1 degree. The length of the transmitter and receiving antennas is half a wavelength, with the feed line split precisely in the middle. The schematic illustration of the electromagnetic interference test setup is shown in Figure 2a. When the distance between the transmission source and the receiver exceeds k/2p, it is considered to be in the far-field protective district (where k is the frequency of the source and p is the 240 VAC power supply). The specimen was positioned in the center, 60 cm from the receiver and transmitter. The transmitter and receiver are linked to a vector network analyzer, which provides a plot of the EMI shielding effectiveness of the sample (see Figure 2b). Figure 1: Experimental flow chart of nanoparticle reinforcement in flexible bio-based polyurethane foam. Figure 2: _Cont_. Response surface methodology examines the relationships between many explanatory variables and one or more response variables. The primary principle of RSM is to obtain an optimal response through a series of carefully prepared tests. Statistical methodologies such as RSM can optimize operational parameters to maximize the production of a specific material. In contrast to traditional methods, statistical techniques can be used to determine the interaction between process factors. If major explanatory factors are suspected, a more elaborate design, such as a central composite design (CCD), can be used to estimate a second-degree polynomial model; however, this is still only an approximation at best. Conversely, the second-degree model can be used to optimize the response variables of interest (maximize, minimize, or achieve a specific aim). Simulation software such as COMSOL Multiphysics is generally used in engineering, manufacturing departments, test laboratories, and scientific research to model designs, devices, and processes. Comsol Multiphysics with add-on modules provides specialized functionality for mechanical, fluid dynamics, electromagnetic interference, acoustics, and chemical applications. In our research, we use a computer-aided design (CAD) kernel to import models into the geometry section in a suitable format. A 3D periodic cartesian lattice with a unit cell containing arbitrarily shaped air-filled pores inside material with pre-defined frequency-dependent electromagnetic parameters is used to model the geometry. The radio frequency (RF) module in COMSOL Multiphysics is used to perform total field calculations of a TE or TM incident wave that excites the structure from the top at a predefined angle of incidence (o) (Port 1). Mesh refinement ensures accurate results by maintaining a minimum element quality of greater than 0.2. S11 and S12 of the structure are calculated over the X-Band with a sampling interval of 0.1 GHz.