Browsing by Author "Das, Nachiketa"

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Analysis of thermal behaviour of a microprocessor using simulation and experiment
(Indian Maritime University, Kolkata Campus, 2023-07) M, Naveen; Das, Nachiketa; Mondal, Sabyasachi; Mishra, Deepak
Thermal management of microprocessor is considered as an important factor in computer appliances. Several analysis and methods have been discussed regarding the scope of heat sink and microprocessor. The shape, size, material of heat sink and velocity and direction of air from the CPU fan plays an important role for thermal management of microprocessor while running the CPU. In this research a numerical and experimental analysis is done for the heat sink and microprocessor in order to understand the thermal response. Numerical analysis is done using software ANSYS 2023 STUDENT R1 version and an infrared thermographic study has been done as part of experimental analysis on the CPU model HP COMPAQ ELITE 8300 SFF. Microprocessor used in this experiment is Intel core i7 chips and exact dimension of CPU chassis have been taken for the numerical part. The thermal images are captured with Fluke Ti 450 camera. The device offers high spectral resolution while taking the thermal image. Analysis shows there are small deviations between the numerical and experimental part. Using nanofluids, a method is also been discussed for thermal management of microprocessor as a substitute for heat sink, for future scope of the project.
Correction to: VLSI-Based Pipeline Architecture for Reversible Image Watermarking by Difference Expansion with High-Level Synthesis Approach /
(Springer Nature, 2018-11-12) Das, Nachiketa
The paper focuses on the VLSI-based digital design and implementation of reversible image watermarking (RIW) architecture using difference expansion (DE). Mathematical simplicity of using a set of linear transformations leads to the choice of DE-based technique for developing hardware design. Moreover, its high performance gain in terms of payload capacity and the visual quality of the watermarked images would make this hardware architecture useful for real-time application on security purpose of medical and military images. High-level synthesis approach with resource-constraint design makes the architecture novel that needs only single adder, subtractor, multiplier, and divider along with 20 registers and 14 multiplexers for embedding. The number of resource required is same for watermark decoding with a modified schedule, which is the specialty of this design. The results obtained after implementation of the architecture on Xilinx Virtex-7 Field Programmable Gate Array (FPGA), Zynq-7000 programmable System-on-Chip (SoC) show the viability of low cost, high speed and real-time use. To process an image block , the latency is 226.733 ns for 150 MHz clock with throughput 35.284 Mbps and the critical path for single cycle is 5.674 ns. The obtained structural similarity (SSIM) performance quality metric of the RIW algorithm from MATLAB simulation is compared with the SSIM obtained from hardware, and excellent agreements between them are observed.
Numerical analysis on the seakeeping performances of a full-scale container ship hull using strip theory
(American Institute of Physics, 2023) Bhatia, Mohammed; Das, Nachiketa; Dutta, Prasun; Chattopadhyay, Himadri
The race of taking more cargo on a ship has increased the size of ships as well as other aspects, such as their capacity and structural complexity, which affect the stability of ships. For naval architects and academics, accurately predicting seakeeping performances is difficult. In order to address this, the seakeeping performance of a container ship hall built by Korea Research Institute for Ships and Ocean Engineering (KRISO), i.e., KRISO container ship hall (KCS) is described in this research utilizing a numerical method. Maxsurf software based on strip theory was used to determine the results, where the containership hull was considered and input motions were applied with appropriate boundary conditions. Later, the ship's heading and speed were changed to see the effect of the seakeeping performance of the container ship. The current study is concentrated on systematic comparative research on the investigation of the ship's pitch, heave, and roll movements in irregular waves. It has been found that rolling motion was the highest at 22 kn at the 60° heading angle, potentially affecting ship stability. The significant amplitude analysis indicates that the roll motion is the largest at 60° of wave direction. The pitch motion response and the heave motion are near for each heading angle when the wave frequency exceeds 0.5 and 1 rad/s, respectively. The calculation findings show that seakeeping performance is directly related to ship direction and speed. Furthermore, threatening heading angles during sailing are classified, which could also help in enhancing ship stability.
Numerical analysis on the seakeeping performances of a full-scale container ship hull using strip theory
(AIP Publishing, 2023-11-01) Bhatia, Mohammed; Das, Nachiketa
The race of taking more cargo on a ship has increased the size of ships as well as other aspects, such as their capacity and structural complexity, which affect the stability of ships. For naval architects and academics, accurately predicting seakeeping performances is difficult. In order to address this, the seakeeping performance of a container ship hall built by Korea Research Institute for Ships and Ocean Engineering (KRISO), i.e., KRISO container ship hall (KCS) is described in this research utilizing a numerical method. Maxsurf software based on strip theory was used to determine the results, where the containership hull was considered and input motions were applied with appropriate boundary conditions. Later, the ship's heading and speed were changed to see the effect of the seakeeping performance of the container ship. The current study is concentrated on systematic comparative research on the investigation of the ship's pitch, heave, and roll movements in irregular waves. It has been found that rolling motion was the highest at 22 kn at the 60° heading angle, potentially affecting ship stability. The significant amplitude analysis indicates that the roll motion is the largest at 60° of wave direction. The pitch motion response and the heave motion are near for each heading angle when the wave frequency exceeds 0.5 and 1 rad/s, respectively. The calculation findings show that seakeeping performance is directly related to ship direction and speed. Furthermore, threatening heading angles during sailing are classified, which could also help in enhancing ship stability.
Numerical study on the seakeeping performances of KCS hull using strip theory
(Indian Maritime University, Kolkata Campus, 2022-08) Bhatia, Mohammed; Das, Nachiketa; Dutta, Prasun
Study on Some Mechanical and Electrical Aspects of Erosion of Epoxy Coating Applied on 316L Stainless Steel
(Indian Maritime University, Kolkata Campus, 2024) Kumar, Rajan; Das, Nachiketa; Shukla, Amarish Kumar
Pure epoxy coatings and epoxy-graphene composite coatings are widely recognized for their protective properties, particularly when applied to stainless steel surfaces. This study investigates key parameters of these coatings applied to SS316L stainless steel by using the dip coating method. The research aims to enhance the understanding of coating characteristics such as coating thickness, surface roughness, capacitance, insulation resistance, and impedance were measured to evaluate the performance of both pure epoxy and epoxy-graphene composite coatings. Stainless steel SS316L is extensively used in various industries due to its excellent corrosion resistance and mechanical properties. However, to further enhance its durability and performance, protective coatings are often applied. Epoxy coatings are known for their good adhesion, chemical resistance, and mechanical strength. Incorporating graphene into epoxy coatings can potentially enhance their electrical conductivity, as well as their barrier properties. The study highlights the erosion of coating and the variation of parameters such as coating thickness, surface roughness, capacitance, insulation resistance, and impedance. The inclusion of graphene in epoxy coatings demonstrated notable variation of capacitance and insulation resistance. Additionally, impedance measurements indicated better electrical stability for graphene-enhanced coatings. The composite coatings showed increased coating thickness and reduced surface roughness, which contributed to variation in various electrical parameters. Additionally, the capacitance and insulation resistance values of the epoxy-graphene coatings were significantly improved, indicating enhanced electrical insulation. Impedance measurements further confirmed the superior barrier properties of the composite coatings.
Study on The Behavior of Light on Erosion in Epoxy Coating on SS316L
(Indian Maritime University, Kolkata Campus, 2025) Das, Nattath Sreejith; Das, Nachiketa; Kolakoti, Aditya
This research employs optical analysis, and light intensity analysis with, three coating systems—pure epoxy, epoxy with 0.1 wt.% graphene, and epoxy with 1 wt.% graphene—were systematically evaluated for their erosion resistance and optical characteristics on SS316L stainless steel substrates. The coating thicknesses ranged from 85 µm to 103 µm, with erosion factor calculated as the reduction from the maximum thickness (103 µm). Pure epoxy exhibited the highest erosion factor of 18 µm, followed by 11 µm for epoxy + 0.1% graphene, and as low as 5 µm for epoxy + 1% graphene, indicating improved erosion resistance with increasing graphene content. Surface roughness (Ra) measurements showed a corresponding rise due to erosion, increasing from approximately 0.33 µm to 1.12 µm for pure epoxy, whereas the increase was limited from 0.19 µm to 0.45 µm in epoxy + 1% graphene coatings, highlighting the protective advantage of graphene modification. Optical analysis using RGB light filters further revealed a progressive increase in deviation values with erosion severity, where pure epoxy exhibited a maximum deviation of 0.165 at highest erosion, compared to only 0.025 for epoxy + 0.1% graphene and 0.008 for epoxy + 1% graphene at lower erosion levels. Additionally, the Energy Index (Ep), sensitive to nanoscale surface roughness, demonstrated a strong inverse correlation with Ra (Pearson Linear Correlation Coefficient, PLCC = 0.91; Mean Absolute Error, MAE = 10.7 nm), while the Structural Color Aliasing Index (SCY) effectively captured macro-level degradation, showing higher correlation (PLCC = 0.93) and a MAE of 0.12 µm. These findings not only confirm the erosion mitigation capability of graphene-reinforced coatings but also establish a robust foundation for non-destructive, real time optical monitoring of coating health using structured light and digital image-based metrics.