POTENTIAL OF CARBON DIOXIDE ABSORPTION IN CONCRETE

Abstract: Cement industry contributes to 5% of global CO2 emissions. To mitigate pollution, there is a need of CO2 sequestration into stable forms. Present research focusses on CO2 being channelized towards an important construction practice. This paper summarizes the potential of CO2 absorption in concrete. To verify CO2 absorption in concrete, an artificial CO2 environment for curing of concrete cubes using dry ice was created. Considering concrete of M20 grade, a comparative experimental study of water cured concrete cubes, CO2 cured concrete cubes, for penetration (using phenolphthalein indicator), and compressive strength was carried out. The result analysis of the tests indicated that CO2 cured concrete cubes showed 22.125% higher compressive strength than water cured concrete cubes and CO2 penetration of 13.5 mm after 2 hours. The rate of CO2 penetration and strength gain in concrete was found to be rapid in the early hours. It is shown that CO2 can prove to be a useful resource in the construction scenario, especially in the precast

Two-Body Abrasive Wear Behaviour of In-Situ Al-TiC Particle Composites: Influence of TiC Reinforcement and Content in the Alloy Matrix and Experimental Parameters

This study pertains to observations made on the abrasive wear response of Al-TiC composites under varying applied load and traversal distance conditions. The influence of TiC particle reinforcement and its content in the matrix on the abrasion characteristics of the samples was investigated. The composites were prepared by generating the reinforcement phase (TiC particles) from within the matrix employing a hybrid in-situ technique consisting of a combination of steps involved in powder and liquid metallurgy routes of synthesizing metal matrix composites. The unreinforced matrix alloy (AA2014) was also tested under identical experimental conditions for comparison purposes. Properties characterized were wear rate, frictional heating and friction coefficient. Microstructural features of the samples and characteristics of wear surfaces, subsurface regions and abrasive medium have also been examined.   The TiC reinforcement led to improved abrasion resistance (inverse of wear rate), the degree of improvement increasing further with the rising concentration of the TiC particles in the alloy matrix. Increasing applied load led to deterioration in the wear behaviour of the samples while a reverse trend was followed as the traversal distance was raised. The severity of frictional heating was noted to increase with load. On the contrary, friction coefficient tended to decrease with increasing load except for the composite containing the highest concentration of TiC wherein a reverse trend was noticed. Both frictional heating and friction coefficient increased sharply with traversal distance initially. This was followed by a reduction in the rate of temperature increase at longer traversal distances whereas friction coefficient was observed to attain steady state condition after showing a decrease in some cases. The presence of TiC reinforcement in the alloy matrix and its increasing content led to a decrease in the friction coefficient and the severity of frictional heating. The observed wear behaviour has been substantiated through the characteristics of abraded surfaces and subsurface regions of the samples and degradation of the abrasive medium. Operating material removal mechanisms have also been examined. &nbsp

The Influence of Lead Suspension in Oil Lubricant on the Sliding Wear Behaviour of Cast Iron

This investigation pertains to the analysis of the sliding wear response of a cast iron over a range of applied pressures in the presence of an oil lubricant. The effect of varying concentrations of lead particles suspended in the oil lubricant on the wear behaviour of the cast iron was also examined. The wear rate increased with pressure initially at a lower rate followed by a higher rate of increase beyond a specific pressure. Furthermore, the presence of suspended lead particles up to a specific concentration in the oil proved beneficial while the trend reversed at still higher concentrations. The extent of frictional heating increased with test duration at a high rate in the beginning of the tests. This was followed by a reduced rate of temperature increase at longer test durations. In some cases, the rate of temperature rise increased once again while it reduced in one case towards the end of the tests. The severity and extent of frictional heating also increased with pressure. Lead addition to the oil lubricant up to a specific concentration led to a reduced degree of heating while the trend reversed at still higher lead contents. Specimen seizure caused significantly high wear rate and frictional heating. The observed wear response of the samples has been explained in terms of specific characteristics like cracking tendency and lubricating and load bearing capacity of various microconstituents of the specimen material. Another important factor of concern affecting wear characteristics was observed to be lubricating film formation and its stability during sliding. The wear behaviour has also been substantiated through the characteristics of wear surfaces and subsurface regions

Commissioning and optimal load dispatch for supplying base and peak loads from Satellite Solar Power Station (SSPS) Using Microwave Wireless Power Transfer (MWPT)

Abstract Solar power on Earth is characterized by its intermittent nature, limiting its practical application to peak loads only. However, this limitation can be overcome by implementing a concept known as Satellite Solar Power Station (SSPS), which involves deploying solar panels in space. Nevertheless, this approach poses various challenges that need to be addressed. One of the primary obstacles lies in determining the feasibility of this plan. This research emphasizes the importance of exploring economically viable methods for establishing SSPS in space, utilizing a Reusable Launch Vehicle and Hohmann’s Transfer technique. To support these proposals, optimization techniques involving multi-stage impulsive maneuvers are employed. Moreover, a comprehensive load dispatch algorithm is mathematically derived and developed to adapt to the changing demands on Earth, achieving a balance between load requirements and antenna size. In addition, discussions are conducted regarding the potential implementation of frequency reconfigurable Microwave systems for future applications. The overall objective of this study revolves around the future deployment and efficient load dispatch from SSPS to meet the energy demands of base loads on Earth, thereby making solar power a viable option

Effect of Amlodipine, Cilnidipine and Diltiazem on lipid profiles of hypertensive rats fed with high fat diet: A comparative study

Objective: The present study was aimed to compare the effect of calcium channel blocker (Amlodipine, Cilnidipine and Diltiazem) on lipid profiles of hypertensive rats fed with high fat diet for four weeks. Methods: Hypertensive rats were randomly allocated into four groups and except hypertensive rats remaining all groups received high fat diet for 4 weeks. At the end of protocol blood pressure was measured by tail cuff method and blood is withdrawn from the retro-orbital puncture, separated serum is used for the assessment of various biochemical parameters. Finally liver and aorta isolated for histological changes. Results: Calcium channel blocker significantly reduces the lipid levels raised in hypertensive rats fed with high fat diet and also restore the pathological changes of aorta and liver tissues. Conclusion: These results indicate that they have a lipid lowering effect due to effect on different stages of metabolism of lipids