The Experts below are selected from a list of 20862 Experts worldwide ranked by ideXlab platform
Nallathambi Arivithamani - One of the best experts on this subject based on the ideXlab platform.
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Cationization of cotton for industrial scale salt-free reactive dyeing of garments
Clean Technologies and Environmental Policy, 2017Co-Authors: Nallathambi Arivithamani, Venkateshwarapuram Rengaswami Giri DevAbstract:Reactive dyeing of cotton garments involves two stages, namely Exhaustion and fixation of dyes. The Exhaustion stage in reactive dyeing requires high quantity of salt. After dyeing process, the highly saline coloured effluent is discharged and the treatment of this effluent at present is not economically viable and making industries look for other alternatives for usage of salt. Cationization of cotton is one of the effective alternatives to overcome the usage of the salt. The present work focuses on the Exhaust Method of cationization of garments at an industrial scale using 3-chloro-2-hydroxypropyl trimethylammonium chloride as a cationic agent. Two commercially popular reactive dyes namely Navy Blue and Green dyes were chosen for dyeing the garments at 10% shade. The results of dyeing were evaluated on the basis of colour strength, dyeing levelness and colour fastness. The uniformity of dye on the fabrics was evaluated based on dyeing levelness and was found to be good for cationized cotton dyed garments. The fastness properties of dyed fabrics to washing and light were good. The dye utilization in the cationized cotton dyed garments was twice as that of the conventionally dyed cotton garments. The environmental hazard posed by the highly saline coloured effluent could be easily mitigated by the salt-free reactive dyeing process.
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Sustainable bulk scale cationization of cotton hosiery fabrics for salt-free reactive dyeing process
Journal of Cleaner Production, 2017Co-Authors: Nallathambi Arivithamani, V. R. Giri DevAbstract:Salt-free reactive dyeing is the need of hour in textile reactive dyeing industries to overcome the problems posed by salt usage. A cationic agent (CA) namely 3-chloro-2-hydroxypropyl trimethylammonium chloride was used to cationize the cotton fabric. At present cold pad batch Method is used to fix the cationic agent to fabrics. In the present work, Exhaust Method of application of cationic agent to knitted cotton goods at an industrial level is proposed. The reaction mechanism and effect of materials to liquor ratio, the molar ratio of NaOH to cationic agent, the temperature on dyeing performance are discussed in detail. The cationization process was optimized based on the colour strength of the cationized cotton fabric dyed with the Black GDNN reactive dye at 7% shade which is widely used for knitted fabric processing in India. Various analytical tools such as Fourier transform infrared spectroscopy and field emission electron microscope with energy dispersive X-ray analyser were used to characterize the efficiency of the cationization process. The change occurring in molecular and supermolecular level due to the cationization process is discussed in detail.
Giri Dev Venkateshwarapuram Rengaswami - One of the best experts on this subject based on the ideXlab platform.
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Salt-free reactive dyeing of cotton hosiery fabrics by Exhaust application of cationic agent
Carbohydrate polymers, 2016Co-Authors: Arivithamani Nallathambi, Giri Dev Venkateshwarapuram RengaswamiAbstract:Reactive dyes are most preferred dyes for dyeing of cellulosic fibres as they are chemically bonded to the fibre which is being dyed and also inexpensive to apply. But the application of reactive dyes onto the cellulosic materials requires a very high concentration of salt since fibre and dyes are anionic in nature. Even with required amount of salt only 65-70% of reactive dyes are Exhausted, remaining 25-30% of dyes are removed as a coloured effluent after dyeing. The present work aims to eliminate salt usage in the reactive dyeing of cellulosic material, especially in cotton hosiery fabrics dyeing industry. In this study, the cationization of cotton fabric was carried out by varying concentration of cationic agent from 20 to 60g/L by an Exhaust Method with the goal to achieve 100% dye utilization and fixation during the salt-free reactive dyeing process. All the dyes taken for the study showed excellent dye Exhaustion, fixation and colour strength properties on the cotton fabrics.
Venkateshwarapuram Rengaswami Giri Dev - One of the best experts on this subject based on the ideXlab platform.
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Cationization of cotton for industrial scale salt-free reactive dyeing of garments
Clean Technologies and Environmental Policy, 2017Co-Authors: Nallathambi Arivithamani, Venkateshwarapuram Rengaswami Giri DevAbstract:Reactive dyeing of cotton garments involves two stages, namely Exhaustion and fixation of dyes. The Exhaustion stage in reactive dyeing requires high quantity of salt. After dyeing process, the highly saline coloured effluent is discharged and the treatment of this effluent at present is not economically viable and making industries look for other alternatives for usage of salt. Cationization of cotton is one of the effective alternatives to overcome the usage of the salt. The present work focuses on the Exhaust Method of cationization of garments at an industrial scale using 3-chloro-2-hydroxypropyl trimethylammonium chloride as a cationic agent. Two commercially popular reactive dyes namely Navy Blue and Green dyes were chosen for dyeing the garments at 10% shade. The results of dyeing were evaluated on the basis of colour strength, dyeing levelness and colour fastness. The uniformity of dye on the fabrics was evaluated based on dyeing levelness and was found to be good for cationized cotton dyed garments. The fastness properties of dyed fabrics to washing and light were good. The dye utilization in the cationized cotton dyed garments was twice as that of the conventionally dyed cotton garments. The environmental hazard posed by the highly saline coloured effluent could be easily mitigated by the salt-free reactive dyeing process.
W.y. Lin - One of the best experts on this subject based on the ideXlab platform.
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Numerical simulation of the spread of smoke in an atrium under fire scenario
Building and Environment, 2009Co-Authors: Tx X. Qin, Yc C. Guo, C. K. Chan, W.y. LinAbstract:The Fire Dynamics Simulator code is used to investigate the smoke movement in an atrium under fire scenario. At first, by comparing with experimental data of the atrium fire under low and high heat release rates, reasonable model constants of Cs and Prt and appropriate grid system are determined for simulating smoke movement in the atrium, the simulation results are in good agreement with those experimental data. Then, the performance of different smoke Exhaust Methods in the atrium is studied. Smoke filling processes are investigated under different natural and enhanced smoke Exhaust Methods. Simulated results show that natural smoke Exhaust Method is preferred when the smoke Exhaust vents are located at the ceiling of the atrium. On the other hand, when the smoke Exhaust vents are located on the walls of the atrium, the higher positions of the smoke Exhaust vents are preferred. In addition, the influence of the fire source locations on the smoke spreading process is presented in this paper, three kinds of fire source locations are studied, they are central fire, side wall fire and corner fire. Results indicate that the descending process of the smoke layer is the slowest when the fire source is at the corner of the atrium.
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Numerical investigation of smoke Exhaust mechanism in a gymnasium under fire scenarios
Building and Environment, 2006Co-Authors: Tx X. Qin, Yc C. Guo, C. K. Chan, W.y. LinAbstract:Abstract The Fire Dynamics Simulator code is used to investigate the smoke filling process in a large building. Initially, the model is used to simulate the smoke descending process in an atrium under fire scenarios. By comparing with experimental data, reasonable model constants of C s and Pr t are determined for simulating smoke movement in buildings with large space. The performance of different smoke Exhaust Methods in a real gymnasium is then studied. Smoke filling processes are investigated under different natural and enhanced smoke Exhaust Methods. Simulated results show that natural smoke Exhaust Method is preferred when the smoke Exhaust vents are located at the ceiling of the gymnasium. On the other hand, when the smoke Exhaust vents are located on the walls of the gymnasium, enhanced smoke Exhaust Methods are preferred. In addition, the influence of ceiling temperature in the gymnasium on the smoke spreading process is presented in this paper. Results indicate that high ceiling temperature slows down the so-called smoke ceiling jet moving horizontally at the ceiling, whereas low ceiling temperature accelerates such smoke ceiling jets.
Giri Dev Venkateshwarapuram Rengaswami - One of the best experts on this subject based on the ideXlab platform.
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Industrial scale salt-free reactive dyeing of cationized cotton fabric with different reactive dye chemistry
Carbohydrate Polymers, 2017Co-Authors: A. Nallathambi, Giri Dev Venkateshwarapuram RengaswamiAbstract:Dyeing of knitted cotton goods in the industry has been mostly with reactive dyes. Handling of salt laden coloured effluent arising out of dyeing process is one of the prime concerns of the industry. Cationization of cotton is one of the effective alternative to overcome the above problem. But for cationization to be successful at industrial scale it has to be carried out by Exhaust process and should be adoptable for the various dye chemistries currently practiced in the industry. Hence, in the present work, industrial level Exhaust Method of cationization process was carried out with concentration of 40 g/L and 80 g/L. The fabrics were dyed with dyes of three different dye chemistry and assessed for its dyeing performance without the addition of salt. Dye shades ranging from medium to extra dark shades were produced without the addition of salt. This study will provide industries the recipe that can be adopted for cationized cotton fabric for the widely used reactive dyes at industrial level.