Department of Electrical & Electronic Engineering (EEE)http://hdl.handle.net/20.500.12228/352024-03-28T18:17:04Z2024-03-28T18:17:04ZDesign and Demonstration of Smartphone-Based ColorimeterRani, Saptamihttp://hdl.handle.net/20.500.12228/8992020-11-11T21:00:16Z2019-12-01T00:00:00ZDesign and Demonstration of Smartphone-Based Colorimeter
Rani, Saptami
In this thesis work, smartphone-based colorimeter is designed and practically implemented utilizing the in-built sensors like CMOS camera, flash LED, and high-power processor of the smartphone. The developed totally self-contained colorimeter is low-cost, light-weight, robust, field-portable and easily accessible. It has smart sensing facilities without the requirement of additional optics and external power supply. The device can be applied for real-time and on-site measurements of different types of analytes in the fields of environmental research, biomedical applications, and agriculture, which are completely absent in the currently used conventional bench-top type colorimetric instruments.
In the real-world, for most of the colorimetric detection, attributes of color such as wavelength, intensity, saturation, etc. vary simultaneously according to the variation of analytes. The conventional smartphone-based colorimeters are mainly designed to measure the analytes considering the change in color information in only one domain which limits the colorimetric measurement in some specific analytes with a narrow band of detection. In this research, the developed smartphone-based colorimeter can quantify any analytes through multiple nonlinear regression based colorimetric assessment in a wide range of detection considering the variation of color attributes in all significant domains.
To demonstrate the smartphone-based colorimeter a 3D optical enclosure is designed and fabricated for ensuring the constant illumination and hence to improve the SNR by isolating the measuring platform from the environmental illumination. Self-referencing is a unique characteristic of the instrument to calculate the color ratio with respect to the colorimetric information of the sample. A customized Android-based smartphone app is developed for the complete functioning of the developed colorimeter. The app is developed with the graphical user interfaces of calibration, assessment of the real-time or previously recorded test samples, save, and share the results of colorimetric measurement for multiple analytes of different colorimetric tests. For the first time, a novel wavelength estimation algorithm is developed to estimate the wavelength information of the reflected light of colorimetric measurement.
To justify the performance of the developed colorimeter, three different colorimetric tests are demonstrated in this research named as Rhodamine B concentration quantifier, digital pH meter, and chlorine concentration quantifier using the Xiaomi Redmi Note 4 smartphone. Three different colorimetric characteristics are found for the three samples: only color tone changes significantly with the variation of Rhodamine concentration, the wavelength of color varies significantly with the variation of pH value in water, and color intensity, wavelength, and saturation all vary simultaneously with the variation of chlorine concentration. For all of the three colorimetric tests, the performance of the designed smartphone-based colorimeter is found excellent compared to the conventional colorimeters. The average error of RhB concentration quantifier within the detection range of (0.2-4.0) PPM is 0.95% whereas the chlorine concentration quantifier shows an average error of 1.16% for the detection range of (0.1-8.0) PPM with sensitivity 0.1 PPM. On the other hand, the digital pH meter detects pH value in the range of (4.0-9.0) with an average of 0.0876% detection error.
It is noted that the present smartphone-based colorimeter is designed and demonstrated using three analytes but the developed device can be applied to measure any colorimetric analytes by proper calibration using the developed smartphone app. So, the developed martphonebased colorimeter could be a cost effective common platform for the colorimetric measurement of various analytes in different fields of applications.
This thesis is submitted to the Department of Electrical and Electronic Engineering, Khulna University of Engineering & Technology in partial fulfillment of the requirements for the degree of Master of Science in Electrical and Electronic Engineering, December 2019.; Cataloged from PDF Version of Thesis.; Includes bibliographical references (pages 82-88).
2019-12-01T00:00:00ZDevelopment of Surface Plasmon Resonance Sensor for Detecting Food PreservativesMoznuzzaman, Md.http://hdl.handle.net/20.500.12228/8982020-11-11T21:00:15Z2020-02-01T00:00:00ZDevelopment of Surface Plasmon Resonance Sensor for Detecting Food Preservatives
Moznuzzaman, Md.
Food preservatives and adulteration is the universal concern of recent days. Particularly, developing states are the main maltreated with food contamination and it is a thoughtful problem in recent years. Formalin is a chemical compound that commonly present in food used for the preservation. Its frequent and illegal addition with food is a danger for human health and psychology. The recurrent ingesting of formalin contaminated food causes uncompromising health sicknesses. This critical issue causes fatal disease like chronic cancer.
Therefore, identification of formalin in food is an extreme need, which is becoming a general
problem in emerging countries.
In this dissertation, formalin is detected quantitatively by designing a Graphene-MoS2 amalgamated 2D nano sheets with a TiO2-SiO2 nano-layered surface plasmon resonance (SPR) based sensor. This sensor distinguishes the presence of formalin utilizing the attenuated total reflection (ATR) approach and inspecting the reflectance vs SPR angle and transmittance vs surface plasmon resonance frequency (SPRF) attributes. Analytical approach for analyzing the sensor performance parameters has been carried out using MATLAB commercial software. The quantitative effect analysis of individual and amalgamated Graphene-MoS2 with TiO2-SiO2 layers has been studied for sensitivity, detection accuracy and quality factor. In addition, optimization of Silver layer thickness is carried out for sensitivity, detection accuracy and quality factor individually.
Electric field distribution through the sensor has been investigated and analyzed by using YEE algorithm on the Lumerical FDTD solution commercial software.
An alternative composite layer sensor structure has also been designed and developed in a configuration of Graphene-PtSe2-Ag-ZnO with BK7 glass prism. Formalin is detected successfully using this sensor structure by angular investigation method. The performance of this alternative sensor structure for formalin detection has been analysis analytically and it shows an outperform with very high sensitivity.
A comparative study among the performance of different composite sensor structure and the proposed sensors are also presented. Another comparison has been carried out between the existing sensor structures and the proposed sensor structures. This is the silver integrated composite sensor that shows highest performance reported by SPR technology. Finally, recommendations for additional research has been anticipated.
This thesis is submitted to the Department of Electrical and Electronic Engineering, Khulna University of Engineering & Technology in partial fulfillment of the requirements for the degree of Master of Science in Electrical and Electronic Engineering, February 2020.; Cataloged from PDF Version of Thesis.; Includes bibliographical references (pages 79-88).
2020-02-01T00:00:00ZMicrostrip Low Pass Filter Realized By EBGS Assisted T-LineAmanullah, Mohammadhttp://hdl.handle.net/20.500.12228/8302020-02-26T21:00:15Z2019-06-01T00:00:00ZMicrostrip Low Pass Filter Realized By EBGS Assisted T-Line
Amanullah, Mohammad
The EBGSs provide passband and stopband performance. In this project the planar conventional structures and the defected ground structures have been described. In uniform conventional structures (circular, rectangular and triangular pattern) it is observed in the scattering parameter performance that the number and the depth of the ripple (-5 db) of the passband are high and the stopband is not much wider. Maximum 10 dB RL bandwidth is 7.4 GHz, the 20 dB rejection bandwidth is 4.8 GHz and the center frequency is 10GHz. The maximum value of isolation is found to be 54dB. Then, the structures with different filling factor (FF), different number of element and same area of different structures are investigated. Then, the results of non-uniform conventional are observed and the results are ripple free in passband. The 10 dB passband RL BW is found to be 6.88 GHz and the 20 dB rejection bandwidth is not found with maximum isolation of 13.26 dB. Next the uniform dumbbell shaped DGS is observed. The 20 dB rejection bandwidth is 4 GHz. The maximum value of isolation is found to be 62 dB. The 3dB cutoff frequency is shifted to 4GHz which provides more than 200% compactness from the conventional structure. Next the result of non-uniform dumbbell shaped DGS have been observed and 10 dB RL-BW is 4.4 GHz, 3 dB cut-off frequency is 4.2 GHz, 20 dB IL-BW is 17.5 GHz and maximum peak of IL is -55 dB have been found. Finally, the hybrid dumbbell shaped DGS is observed and we have found the best performance. The best performance of 10 dB RL-BW is 4.1 GHz, 3 dB cut-off frequency is 4.4 GHz, 20 dB IL-BW is more than 19 GHz and maximum peak of IL is -68 dB. So, we have found the best performance in the hybrid dumbbell shaped DGSs. The designs are more compact than the conventional designs and able to remove the unwanted spurious transmission in the band rejection region.
Finally, the insertion loss (IL) and return loss (RL) performances of the LPFs (non-uniform triangular dumbbell shaped DGSs and hybrid DGSs) have been compared. It is seen that they provide improved performance in terms of the ripple suppression in the passband and IL bandwidths. Thus we have realized microwave LPF by EBGS assisted T-Lines. At last the physical representation of designs and the validification of the results are provided as for the validification of the work.
This thesis is submitted to the Department of Electrical and Electronic Engineering, Khulna University of Engineering & Technology in partial fulfillment of the requirements for the degree of Master of Science in Electrical and Electronic Engineering, June 2019.; Cataloged from PDF Version of Thesis.; Includes bibliographical references (pages 74-78).
2019-06-01T00:00:00ZFinite-State Predictive Current Control of a Simplified Three-Level Neutral-Point Clamped InverterTariquzzaman, Md.http://hdl.handle.net/20.500.12228/8252021-01-14T21:00:23Z2019-11-01T00:00:00ZFinite-State Predictive Current Control of a Simplified Three-Level Neutral-Point Clamped Inverter
Tariquzzaman, Md.
Multilevel inverter is one of the most important parts in renewable energy based power generating section as well as in motor drive applications. The quality of an inverter system depends on current total harmonic distortion (THD), switching loss, fault tolerant ability, dynamic responses, voltage stress, common mode voltage etc. Multilevel inverter yields low current THD, less voltage stress across the semiconductor switches and low switching frequency and thus less switching loss. However, using more number of semiconductor devices and neutral point voltage variation are the common problems for a neutral point clamped inverter. This is why different topologies of multilevel inverter are available in the literature in order to solve the aforementioned problems. The control scheme of a multilevel inverter also plays an important role to guarantee system’s performance. Recently, model predictive control (MPC) draws much attention to the researchers for its intuitive features and easy handling of nonlinearities of a system. The controller uses system model to predict the future behavior of the system over a prediction horizon. The control objectives are met by minimizing a predefined cost function that represents the expected behavior of the system. The objective of the proposed research work is to control the output load current of a three level simplified NPC (3L-SNPC) inverter topology using MPC. The simplified NPC inverter is considered, because less number of semiconductor devices used in the topology, even though further investigation is required on different factors such as voltage stress, common mode voltage, losses and switching frequency. MPC is used as controller because it can handle the dc link capacitors voltages balancing problem in a very intuitive way. Moreover, the average switching frequency reduction and over current protection can be easily implemented. Simulation results show that the proposed 3L-SNPC yields similar current THD, transient and steady state responses, voltage stress on the switches at the load side and over current protection capability as the conventional diode clamped based NPC inverter system. The two dc-link capacitor voltages are balanced properly with a neutral point voltage variation of close to zero. However, in comparison with the conventional NPC inverter, the proposed system is 15.25% computationally expensive which yields long execution time and thus less sampling frequency. In this study, two simplified MPC strategies are proposed for the 3L-SNPC inverter system in order to reduce the computational burden: single voltage vector prediction based MPC and selective voltage vector prediction based MPC. Both simplified strategies yield similar performance as the conventional MPC. The required execution times for the simplified MPC strategies are tested on hardware dSPACE 1104 platform. It is found that the single voltage vector prediction based MPC and the selective voltage vector prediction based MPC are computationally efficient by 8.28% and 62.9%, respectively, in comparison with the conventional MPC strategy. However, the average switching frequency and the overall loss in the proposed 3L-SNPC inverter are higher by 83.33% and 46.3%, respectively, than the conventional NPC inverter for a specified load current.
This thesis is submitted to the Department of Electrical and Electronic Engineering, Khulna University of Engineering & Technology in partial fulfillment of the requirements for the degree of Master of Science in Electrical and Electronic Engineering, November 2019.; Cataloged from PDF Version of Thesis.; Includes bibliographical references (pages 66-72).
2019-11-01T00:00:00Z