Area of Research
Research is the pursuit of knowledge and understanding that contributes to the improvement of society. In my role as a Fire engineer, I provide consulting services to enhance fire safety. My PhD research focuses on paper-based microfluidic devices, encompassing theoretical, analytical, and experimental investigations. The primary application of my research is the development of a technique for identifying adulterants in liquid foods. However, this task presents intricate challenges as it involves the complex process of detecting different types of adulterants on a laboratory chip device. Consequently, the research work is subdivided into the following domains of study to address these multifaceted issues.
Fundamental understanding of Fire Dynamics
The Fire Dynamics Simulator (FDS) is a computational fluid dynamics (CFD) model specifically designed to simulate fluid flow driven by fire. This software utilizes numerical methods to solve a large eddy simulation form of the Navier-Stokes equations, which is suitable for analyzing low-speed, thermally-driven flow. FDS focuses on accurately depicting the transport of smoke and heat from fires, allowing for a comprehensive understanding of fire evolution. By employing this model, researchers can gain valuable insights into the complex dynamics of fire and its impact on the surrounding environment.
a) One aspect of my research involves conducting Computational Fluid Dynamics (CFD) studies of fire scenarios. This entails using computer simulations to analyze factors such as visibility, temperature distribution, smoke logging, and occupant density during fire incidents. By employing CFD techniques, we can gain insights into how fires behave in different environments and develop strategies to enhance fire safety and evacuation procedures.
b) Another important component of my research is the preparation of subject matter reports and engaging in client discussions. These reports serve as comprehensive documents that provide detailed analysis, recommendations, and findings related to fire engineering. Additionally, engaging in discussions with clients allows for a deeper understanding of their specific requirements and enables the development of tailored solutions to address their fire safety concerns.
c) In order to gain a comprehensive understanding of fire engineering issues, my research also involves conducting quantitative and qualitative analyses. This entails examining various aspects such as fire dynamics, structural integrity, material properties, and evacuation strategies. By conducting these analyses, we can identify potential risks, evaluate the effectiveness of existing fire engineering measures, and propose improvements to mitigate fire hazards. This multidimensional approach ensures a thorough examination of fire-related challenges and aids in developing robust fire engineering solutions
Fundamental understanding of Capillary rise in paper strips
The flow of liquid through porous media occurs effortlessly, driven by capillary action and without the need for additional energy. The pioneering work of Darcy involved experimental investigations into liquid flow in porous materials. In 1921, two researchers, Lucas and Washburn, established the Lucas-Washburn (L-W) equation, which correlates the capillary height of liquid in porous media with its rising time. This phenomenon of capillary flow encompasses the interaction of multiple phases, including liquid and air, within the micropores of the porous material. In our research, we have focused on examining various physical properties of paper that can influence the flow of liquid, such as porosity and permeability. Through a combination of experiments and simulations, we have studied the behaviour of liquid flow in paper strips. This approach has been applied to identify the water content in milk, showcasing the practical application of our investigations.
Imbibition of liquid through paper substrate under controlled environmental conditions
Liquid spreading on open surfaces is a commonly observed phenomenon, but it becomes more intricate when the surface is porous. The physics behind liquid spreading in materials like paper or fabrics becomes even more complex due to factors such as liquid evaporation and fiber swelling. In this particular study, we conducted experiments to investigate the process of liquid imbibition on paper strips under controlled environmental conditions. We compared the effects of using hydrophobic boundaries with those of not using them and observed distinct influences on the wicking phenomenon. Additionally, we developed new analytical models that can predict the practical conditions of liquid spreading in porous materials. These findings contribute to a better understanding of the underlying mechanisms involved and can potentially inform the development of improved strategies for managing liquid spreading in various applications.
Paper-based microfluidic device to detect milk adulteration
Milk is highly valued for its rich nutritional content, including protein, fat, carbohydrates, vitamins, and more. As a crucial component of a balanced diet, the demand for milk is substantial. Unfortunately, the business of milk production and distribution is susceptible to adulteration, which can compromise its quality. With the constant supply and increased demand for milk, some unscrupulous individuals may resort to contamination as a means to meet the needs of the large population.
To address this issue, various qualitative and quantitative methods have been developed to detect adulterated milk. One effective approach is the use of paper-based microfluidic devices, which offer real-time testing capabilities for adulteration detection. These devices provide a reliable and portable solution for rapidly identifying adulterants in milk. By leveraging the advantages of paper-based microfluidics, such as their simplicity, low cost, and ease of use, these devices enable quick and efficient testing, ensuring the quality and safety of milk for consumers.
By employing these innovative technologies, we can safeguard the integrity of milk production and distribution, protecting consumers from the potential health risks associated with adulterated milk.
Fundamental research of experimental and numerical analysis of liquid flow through marker reservoir
The flow of liquid through a marker reservoir is a phenomenon commonly observed in various writing instruments, such as markers and highlighters. A marker reservoir is a container that holds the liquid ink or dye used for writing or drawing. The design of the reservoir is crucial for ensuring a consistent and controlled flow of liquid to the marker tip. Inside the reservoir, a combination of capillary action, gravity, and pressure gradients facilitates the flow of liquid ink. Capillary action, driven by the surface tension of the liquid, allows the ink to be drawn up into the marker tip. This occurs because the tip of the marker, typically made of a porous material, has narrow channels or fibers that provide a high surface area for the ink to interact with. Gravity also plays a role in the flow of liquid, as it pulls the ink downward from the reservoir toward the marker tip. The force of gravity helps to maintain a steady flow and prevents the ink from pooling or leaking out of the marker. Additionally, pressure gradients, created by the user applying pressure to the marker tip, can control the flow rate of the liquid. By squeezing or pressing the marker, the user can increase the pressure within the reservoir, forcing the ink to flow more quickly. Releasing the pressure reduces the flow rate or stops it altogether. The proper design and construction of a marker reservoir are essential to ensure efficient and consistent liquid flow. Factors such as the size and shape of the reservoir, the properties of the ink, and the characteristics of the marker tip all contribute to the overall performance of the marker. Manufacturers carefully consider these factors to achieve optimal ink flow, preventing issues like clogging, drying out, or excessive leakage.
In conclusion, the flow of liquid through a marker reservoir involves a combination of capillary action, gravity, and pressure gradients. Understanding these principles allows manufacturers to design marker reservoirs that provide a reliable and controlled flow of ink, resulting in a smooth and consistent writing or drawing experience for the user.
Colourimetric detection of heavy metals using paper-based devices
Water pollution has been a great concern for all living organisms on earth. Heavy metals are one of the major pollutants generating from various sources like factories, fertilizers, etc. They tend to accumulate in aquatic ecosystem as they’re not biodegradable. This project aims to detect heavy metals in water samples using colorimetry on the paper based analytical devices. Due to their advantages of speedy analysis, environmental friendliness, cost efficiency, and the capacity to actualize the flow of fluid without external power, paper-based microfluidic analytical devices (μPADs have shown considerable potential in the field of analysis. In this work, experiments for verifying colorimetric reagent for corresponding heavy metal ion has been done and the results are shown for a novel detection method which involves use of glossy paper. Using the proposed method significantly increases the accuracy, limit of detection (LOD) while reducing the cost of detection as compared to traditionally used methods. Surface properties of glossy paper and whatman filter paper have been compared to show the difference in phenomenon involved during colorimetric detection. We have reported experimental LOD of 1mg/L, 2mg/L and 0.5mg/L for Cu(II), Ni(II), and Co(II) respectively. The linear range for is also computed using the calibration curve. Specificity and interference tests results have been discussed involving multiple metal ions to replicate the practical scenarios. This report also discusses the evaporation phenomenon and using an optical goniometer the contact angle study during evaporation has been done. Glossy paper has shown great potential as both a qualitative and quantitative analytical platform. It is a one-step assay detection method using colorimetric detection. Finally, the cost analysis has been done. This study can be used to develop a robust microfluidic paper-based device which can be used to detect adulterants and impurities in various media hence making it an industrially practical solution.
Dropwise condensation on metal surfaces
Water vapor condenses in the surface when the surface temperature is lower than the dew point temperature. Condensation is very important for many industrial processes such as thermal power plants, refrigeration systems, water distillation, air conditioning system, nuclear reactors etc. There are two modes of condensation, one is Filmwise Condensation (FWC) and the other one is Dropwise Condensation (DWC). DWC gives more heat flux at the same temperature difference compared to FWC. However, sustaining DWC for a longer duration is difficult to achive in practice. DWC mainly occurs on lower-energy surfaces but in general, most of metal surfaces have high surface energy. The nucleation densities for the hydrophilic surfaces are higher than the hydrophobic surfaces. On pure metal, dropwise condensation (DWC) occurs at low heat flux or at the initial phase of the condensation. In practical engineering applications, the condensate droplets coalesce and form a continuous film, leading to film condensation (FWC). During FWC, the liquid film offers considerable resistance for heat transfers as well as decreases the new heterogeneous nucleation sites.
The objective of this project is to perform experiments on dropwise condensation on different surfaces. An experimental setup has been built to perform the condensation experiments. In this project, I performed DWC on different wettability surfaces and got the HTC at different temperatures and Relative Humidity (RH) conditions. I prepared hydrophilic (mirror-finish Aluminum) and superhydrophilic surfaces and performed condensation experiments. I found DWC on hydrophilic surfaces and FWC on superhydrophilic surfaces. I have calculated the heat transfer coefficient for both DWC and FWC conditions. The work can be extended to study the fundamental understanding of condensation behavior on Superhydrophobic and patterned wettable surfaces, Cu and Stainless steel surfaces.
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