Browsing by Author "Panawala, PSS"

Now showing 1 - 6 of 6

item: Conference-Abstract
Development of an exhaled breath analyzer for early detection of diseases
(Department of Materials Science and Engineering, University of Moratuwa., 2023) Panawala, PSS; Tissera, PIU; Amarasinghe, DAS; Sivahar, V
Chronic Kidney Disease (CKD) represents a significant global health burden, with early detection being crucial for effective management and improved patient outcomes. This research focuses on the development of an Exhaled Breath Analyzer (EBA) as a non-invasive and potentially cost-effective tool for early detection of CKD. Ammonia (NH3) has been identified as a key marker in exhaled breath to diagnose CKD patients as the concentration of ammonia among healthy people is about 0.5-5 ppm and in CKD patients it can be more than 25 ppm. In this work, an ammonia gas sensor based on Polyaniline (PANI) was fabricated using a custom made Interdigitated capacitive sensor (IDC-S). PANI films were successfully deposited on the IDC-S using the solution casting method. The sensor responded to a low ammonia concentration of 50 ppm with a capacitance change of 10% with respect to capacitance in air in room temperature. Furthermore, the response of the sensor increased to 44% as the concentration increased to 300 ppm. This showed a good linear relationship between sensor response and ammonia concentration. Furthermore, the effect of relative humidity on the sensor was also studied and a significant change in capacitance of the sensor was observed with changing relative humidity levels. Moreover, the sensor response to a fixed ammonia concentration of 200 ppm at different humidity levels was studied and it diminished from 26% to 4% as the humidity level increased from 20% to 90%.
item: Conference-Abstract
Development of an exhaled breath analyzer for early detection of diseases
(Department of Materials Science and Engineering, University of Moratuwa., 2023-07-28) Panawala, PSS; Tissera, PLU; Amarasinghe, DAS; Sivahar, V
Chronic Kidney Disease (CKD) represents a significant global health burden, with early detection being crucial for effective management and improved patient outcomes. This research focuses on the development of an Exhaled Breath Analyzer (EBA) as a non-invasive and potentially cost-effective tool for early detection of CKD. Ammonia (NH3) has been identified as a key marker in exhaled breath to diagnose CKD patients as the concentration of ammonia among healthy people is about 0.5-5 ppm and in CKD patients it can be more than 25 ppm. In this work, an ammonia gas sensor based on Polyaniline (PANI) was fabricated using a custom made Interdigitated capacitive sensor (IDC-S). PANI films were successfully deposited on the IDC-S using the solution casting method. The sensor responded to a low ammonia concentration of 50 ppm with a capacitance change of 10% with respect to capacitance in air in room temperature. Furthermore, the response of the sensor increased to 44% as the concentration increased to 300 ppm. This showed a good linear relationship between sensor response and ammonia concentration. Furthermore, the effect of relative humidity on the sensor was also studied and a significant change in capacitance of the sensor was observed with changing relative humidity levels. Moreover, the sensor response to a fixed ammonia concentration of 200 ppm at different humidity levels was studied and it diminished from 26% to 4% as the humidity level increased from 20% to 90%.
item: Conference-Full-text
Feasibility assessment of obtaining kinetic parameters for independent simultaneous first- order reactions using friedman isoconversion analysis
(IEEE, 2023-12-09) Panawala, PSS; Kanchana, PK; Amarasinghe, DAS; Attygalle, D; Samarasekara, AMPB; Weragoda, VSC; Abeysooriya, R; Adikariwattage, V; Hemachandra, K
This research investigates the effect of two independent first-order reactions occurring concurrently within a given temperature range. A theoretical simulation-based approach was employed to analyze the influence of these concurrent reactions on the kinetic parameters obtained using the Friedman isoconversion method. A novel technique for separating the kinetic parameters of two reactions is also discussed here. The results demonstrate that, in most cases, the disparity between the actual activation energies of the two reactions and the values obtained through the Friedman isoconversion method is minimal, with an error of less than 1%. However, when the two first-order reactions exhibit DTG peaks within the same temperature range, the error can escalate to as high as 15%. This investigation provides valuable insights into the errors associated with kinetic parameter estimations on multiple simultaneous reactions. The findings contribute to a more indepth understanding of reaction kinetics and offer important substances for experimental design and reaction optimization in various fields.
item: Conference-Full-text
New strategy for synthesizing catalyst-free hcl-doped polyaniline
(IEEE, 2023-12-09) Dinujaya, N; Narangoda, C; Karunanayake, L; Panawala, PSS; Tissera, I; Samarasekara, AMPB; Amarasinghe, DAS; Abeysooriya, R; Adikariwattage, V; Hemachandra, K
A new low-cost strategy for the catalyst-free synthesis of HCl-doped polyaniline (PANI) was developed. A 50:50 (water/hydrogen peroxide) solution was used as an oxidant and a 1M HCl solution was used as an acidic dopant. The synthesis was simple and was carried out at 4 °C without mechanical or magnetic agitation. The volume ratio for aniline to hydrogen peroxide was 3:1. It is proposed that the reaction proceed through radical polymerization, in which hydroxyl radicals (OH•) are generated by the action of hydrogen peroxide (H2O2) to polymerize aniline. The formation of HCl-doped Polyaniline (PANI) was confirmed using of Fourier-transform infrared spectroscopy, UV-Vis spectroscopy, and thermogravimetric analysis. The purification process is easier, and the risk of harmful byproducts is reduced as the reaction continues under benign conditions. Additional benefits of using H2O2 as an oxidizing agent include higher polymer purity, increased scalability, and improved control over polymerization kinetics. Overall, this novel synthetic approach using 50:50 (water/hydrogen peroxide) as an oxidizing agent for PANI offers a promising avenue for efficient, sustainable, facile, and catalyst-free production of HCl-doped PANI, with potential uses in a plethora of areas, including electronics, energy, and sensing of volatile gases at relatively low concentrations. The synthesized polyaniline film exhibited good conductivity (0.010197± 0.000174 Sm-1) and low resistivity (100.6535±1.64424 Ωm-1). The addition of Cetyl Trimethyl Ammonium Bromide (CTAB) as a modification agent imparted hydrophobic properties to the initially hydrophilic polyaniline. This modification resulted in a significant increase of approximately 290% in the contact angle, indicating enhanced hydrophobicity.
item: Conference-Full-text
Polyaniline film-based interdigitated capacitive sensor for ammonia gas detection
(IEEE, 2023-12-09) Panawala, PSS; Tissera, I; Dinujaya, N; Amarasinghe, DAS; Narangoda, C; Karunanayake, L; Attygalle, D; Weragoda, VSC; Samarasekara, AMPB; Abeysooriya, R; Adikariwattage, V; Hemachandra, K
In this work, an ammonia gas sensor based on Polyaniline(PANI) was fabricated using a custom made Interdigitated capacitive sensor(IDC-S). PANI films were successfully deposited on the IDC-S using the solution casting method. The sensor responded to a low ammonia concentration of 50 ppm with a capacitance change of 10% with respect to capacitance in air in room temperature. And the response increased to 44% as the concentration increased to 300 ppm. This showed a good linear relationship between sensor response and ammonia concentration. Furthermore, the effect of relative humidity on the sensor was also studied and it showed that there is a significant change in capacitance of the sensor as the relative humidity levels changed. Moreover, the sensor response to a fixed ammonia concentration of 200 ppm at different humidity levels was studied and it diminished from 26% to 4% as the humidity level increased from 20% to 90%.
item: Conference-Full-text
Unveiling the barrier: a simulation study on face mask filtration
(IEEE, 2023-12-09) Panawala, PSS; Mudalige, SP; Amarasinghe, DAS; Attygalle, D; Samarasekara, AMPB; Weragoda, VSC; Abeysooriya, R; Adikariwattage, V; Hemachandra, K
In recent years, there has been significant discussion surrounding fibrous filters, particularly in relation to respiratory masks. Manufacturing fibrous filters involves paying close attention to the sticking coefficient of fibers and ensuring its stability under different climatic conditions. This paper presents an optimal range of filter characteristics that maximize filtration efficiency, considering factors such as sticking coefficient, inter-fiber distance, and fiber diameter. The findings were obtained through computational modeling of aerosol diffusion within fibrous filters. The identified optimal region demonstrates that achieving nearly maximum filtration efficiency does not require indiscriminately increasing the sticking coefficient; surpassing a marginal value of 0.5 is sufficient. This outcome can prevent unnecessary overdesign and contribute to reducing production costs.