43 research outputs found
Vicenin-2 inhibits Wnt/β-catenin signaling and induces apoptosis in HT-29 human colon cancer cell line
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Potent chemopreventive effect of mangiferin on lung carcinogenesis in experimental Swiss albino mice
No full textEffect of simvastatin on neuroinflammation in microglial cells via mitogen-activated protein kinase and nuclear factor κB pathways
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Effects of platform induced pitching motion on the aerodynamics of a FOWT
No full textThe hunt for new methods to harness wind energy is at an all-time high as wind energy quickly overtakes other renewable energy sources. Deep waters are promising alternatives with higher average wind speed (thus, higher yields) and also due to lesser availability of land on shore. Even though the design of the blades and rotor of a FOWT is largely similar to that of onshore counterparts, they are mounted on floating platforms, unlike the fixed platforms on onshore wind turbines. Due to the excitation from wind and waves, these foundations are made to oscillate in all six degrees of freedom. Pitch and surge motions have the most significant effects out of all the possible types of motions. Since surging motion comes closest to the pitching motion, this study attempts to compare the aerodynamics of these two motions by simulating a pitching wind turbine using an actuator disk CFD model. This study can also be considered a continuation of the actuator disk study of the surging motion.The primary objective of this thesis is to understand the differences between the aerodynamics of a surging and a pitching wind turbine using an actuator disk model. The actuator disk is made to pitch sinusoidally with the prescribed pitching frequency and amplitude. In order to identify the effects of motion and thrust prescription separately, three different types of actuator disk models were created. Using the first model, which simulates a pitching actuator disk with constant thrust, the effects of pitch motion are captured. The second model which simulates a still actuator disk with dynamic loading gives the effects of change in thrust on the rotor. The last model, which is a combination of the first two with a pitching actuator disk under dynamic loading, attempts to simulate a more realistic pitching actuator.On comparing the surge and pitch motions of the actuator disk, the stark difference observed is the meandering in wake due to flow shear and asymmetric tip vortex shedding. At high thrust and low-frequency cases, turbulent wakestates are also visible in the wake. At higher frequencies, they are nearly as strong as the tip vortices and introduce non-linear effects on the induction field. They also tend to introduce varied dynamic responses based on the radial location. It was also observed that the motion introduces a phase delay that varies with the radial position on the rotor.Thus, this project provides a comprehensive view of the effects of platform pitching motion on a FOWT and it differences with respect to the surging dynamics. This project also confirms that an actuator disc model is capable of reproducing the effects of pitching in a FOWT. Using the insights provided in this thesis, a better dynamic inflow can be developed for use in industriesAerospace Engineerin
Quantifying the total cost of ownership by modelling product lifetime
No full textConsumer products produced in contemporary times face the issue of deteriorating durability, repairability and service life compared to products of yesterday. This deterioration is part of a bigger issue called planned obsolescence. Due to a ‘need’ to buy new products regularly, there is rampant consumerism which has created a decrease in raw-materials and an increase in the products and materials entering the waste streams. Therefore, it is imperative that this “cradle-to-grave” model is stopped. The EU and various governments in the EU have proposed legislation to transition from today’s linear economy to a circular economy. As part of that, there is greater emphasis placed on a product’s repairability, durability and product lifespan.Repair scorecards are used to evaluate products on those parameters. However, the current scorecards have abstract scores that are difficult to interpret. Therefore, this thesis proposes a quantitative tool that calculates the total cost of ownership (TCOO) and service life of a product by modelling product lifetimes using failure modes. This thesis begins with performing a literature study of linear economy and planned obsolescence, current scorecards, and their limitations. Questionnaires and interviews were conducted to understand what consumers wanted from a repair scorecard. The results from these were used to design the label and website of the TCOO tool. A system was created to facilitate the TCOO Excel tool, label, and website. The mathematical model to calculate the TCOO was built-in to an Excel tool, and sample data was used to iterate upon them. Sensitivity analysis was also conducted to test the Excel tool. User tests were conducted to test if the Excel tool was intuitive to use and the flow of the tool iterated upon. User tests were conducted to refine the design of the label and the website. The main contribution of this thesis lies in presenting the factors of repairability, durability and product lifespan in terms of cost, modelling product lifetimes, and moving from a priority component-based calculation system to a failure mode-based system. Using this tool, consumers can make informed purchase decisions, and manufacturers get data regarding failure, and legislators get data to introduce new laws and mandates. Integrated Product Desig
Exposure to polycyclic aromatic hydrocarbons with special focus on cancer
No full textABSTRACTPolycyclic aromatic hydrocarbons (PAHs) are a group of compounds consisting of two or more fused aromatic rings. Most of them are formed during incomplete combustion of organic materials such as wood and fossil fuels, petroleum products, and coal. The composition of PAH mixtures varies with the source and is also affected by selective weathering effects in the environment. PAHs are ubiquitous pollutants frequently found in a variety of environments such as fresh water and marine sediments, the atmosphere, and ice. Due to their widespread distribution, the environmental pollution due to PAHs has aroused global concern. Many PAHs and their epoxides are highly toxic, mutagenic and/or carcinogenic to microorganisms as well as to higher forms of life including humans. The main aim of this review is to provide contemporary information on PAH sources, route of exposure, worldwide emission rate, and adverse effects on humans, especially with reference to cancer
