Journal of Scientific and Technical Research
Issue 1, 2019
Original Articles
Abstract
Simulation studies of batch distillation of some non-ideal binary systems have been carried out and reported in this work. Differential distillation as well as batch distillation at total reflux has been simulated through a semirigorous unsteady state mathematical model, implemented via codes developed in-house. The Wilson model has been used to represent non-ideality in the liquid phase and predictvapour- liquid equilibrium (VLE) data. Parametric studies of the composition and temperature profiles have been carried out. Heating and cooling requirements for batch distillation operation have also been estimated. The model presented here can be used for simulating the start-up of any distillation column for even multi-component non-ideal systems, as long as the VLE data are available for them, without requiring any commercial simulation software. The model can also be extended to simulation of batch distillation columns with a finite value of reflux ratio after suitable modification of the governing equations. Thus it can be used for preliminary design work as well.
Simulation studies of batch distillation of some non-ideal binary systems have been carried out and reported in this work. Differential distillation as well as batch distillation at total reflux has been simulated through a semirigorous unsteady state mathematical model, implemented via codes developed in-house. The Wilson model has been used to represent non-ideality in the liquid phase and predictvapour- liquid equilibrium (VLE) data. Parametric studies of the composition and temperature profiles have been carried out. Heating and cooling requirements for batch distillation operation have also been estimated. The model presented here can be used for simulating the start-up of any distillation column for even multi-component non-ideal systems, as long as the VLE data are available for them, without requiring any commercial simulation software. The model can also be extended to simulation of batch distillation columns with a finite value of reflux ratio after suitable modification of the governing equations. Thus it can be used for preliminary design work as well.
Restricted
Abstract
Kidney stone issues in humans have doubled since the early seventies. A variety of morphologies have been observed during stone removal from the kidney. The formation of these morphologies depends on various factors such as pH, temperature, impurities and composition of the nutrients remaining in the kidney after filtration. Growth kinetics, rate and morphology of stones depend strongly on the local concentration of insoluble species and nucleation surface in the kidney. In this paper, we have investigated the effect of pH, sugar (C6H12O6) and magnesium as an excess impurity on the kidney stone growth. At lower pH of the solution fat prism crystals are observed. Whereas at higher pH (>7), long fat needle crystals with large aspect ratio (length to width) are observed. The coarsening experiments showed further growth in different shapes. The impurity enhanced the colorization. The re-melting experiments were performed to understand the dissolution process of stones, revealing that during dissolution the joining material breaks first leaving the large faceted crystals undissolved. In addition, it was also found that the effect of excess sugar caused significant variations in the morphology and produced brown colored stones. Crystals containing sugar also retained significantly higher quantities of potassium compared to undoped stones. Finally, the effect of additional impurities e.g. magnesium on stone formation and morphology were studied demonstrating the ability to produce mushroom and cauliflower type morphologies. Thermogravimetric analysis revealed that characteristics of stones with sugar were very different, with dehydration of stones taking continuously as function of temperature.
Kidney stone issues in humans have doubled since the early seventies. A variety of morphologies have been observed during stone removal from the kidney. The formation of these morphologies depends on various factors such as pH, temperature, impurities and composition of the nutrients remaining in the kidney after filtration. Growth kinetics, rate and morphology of stones depend strongly on the local concentration of insoluble species and nucleation surface in the kidney. In this paper, we have investigated the effect of pH, sugar (C6H12O6) and magnesium as an excess impurity on the kidney stone growth. At lower pH of the solution fat prism crystals are observed. Whereas at higher pH (>7), long fat needle crystals with large aspect ratio (length to width) are observed. The coarsening experiments showed further growth in different shapes. The impurity enhanced the colorization. The re-melting experiments were performed to understand the dissolution process of stones, revealing that during dissolution the joining material breaks first leaving the large faceted crystals undissolved. In addition, it was also found that the effect of excess sugar caused significant variations in the morphology and produced brown colored stones. Crystals containing sugar also retained significantly higher quantities of potassium compared to undoped stones. Finally, the effect of additional impurities e.g. magnesium on stone formation and morphology were studied demonstrating the ability to produce mushroom and cauliflower type morphologies. Thermogravimetric analysis revealed that characteristics of stones with sugar were very different, with dehydration of stones taking continuously as function of temperature.
Restricted
Abstract
India’s informal sector of solid waste management involving rag pickers, middlemen and wholesale dealers face relative apathy at the community level. Lack of sustainable commitment from the government and stringent implementation of regulatory framework to manage waste has resulted in negative impacts of this obstinate issue. Rag pickers from diverse age groups including women, do not have any social or occupational recognition in the country and also suffer from local injuries, infections and systemic illnesses. There is hardly any published evidence of the key determinants of health of ragpickers, gender or age specific health, awareness on handling wastes and hygiene practices. This paper presents a systematic analysis of the morbidity profile of ragpickers to assess their health more so, from non-governmental organisations. This research involved 306 ragpickers which were divided into seven age groups and surveyed to ascertain the most prominent disease for a particular age group. A Neutrosophic health rating model has been proposed employing Neutrosophic Fuzzy Set theory [5]. This model can be used to implement long term occupational health monitoring programs and health awareness campaigns.
India’s informal sector of solid waste management involving rag pickers, middlemen and wholesale dealers face relative apathy at the community level. Lack of sustainable commitment from the government and stringent implementation of regulatory framework to manage waste has resulted in negative impacts of this obstinate issue. Rag pickers from diverse age groups including women, do not have any social or occupational recognition in the country and also suffer from local injuries, infections and systemic illnesses. There is hardly any published evidence of the key determinants of health of ragpickers, gender or age specific health, awareness on handling wastes and hygiene practices. This paper presents a systematic analysis of the morbidity profile of ragpickers to assess their health more so, from non-governmental organisations. This research involved 306 ragpickers which were divided into seven age groups and surveyed to ascertain the most prominent disease for a particular age group. A Neutrosophic health rating model has been proposed employing Neutrosophic Fuzzy Set theory [5]. This model can be used to implement long term occupational health monitoring programs and health awareness campaigns.
Restricted
Abstract
Reverse micelles and microemulsions of cetyltrymethylammonium bromide (CTAB) have been prepared over a wide range of compositions and the physicochemical properties have been studied in detail. Conductivity and density increase, while the refractive index decreases with increasing volume fraction of water (fW) or water to surfactant molaReverse micelles and microemulsions of cetyltrymethylammonium bromide (CTAB) have been prepared over a wide range of compositions and the physicochemical properties have been studied in detail. Conductivity and density increase, while the refractive index decreases with increasing volume fraction of water (ϕ_w) or water to surfactant molar ratio (w_0) in the reverse micelles and microemulsions. Turbidity, viscosity and surface tension plotted against ϕ_w show unusual patterns with increasing ϕ_w indicating different microstructures in microemulsions and reverse micelles. Percolation theory was applied on conductivity results to identify microstructures of microemulsions and reverse micelles. The conductivity values show percolation thresholds (ϕ_c)which correlate well with viscosity, turbidity and surface tension results. The micostructural changes from water-in-oil (w/o) to bicontinuous (BC), ϕ_C1 and BC to oil-in-water (o/w), ϕ_C2 give rise to phase transitions in percolation thresholds in the microemulsions. Phase transitions at these percolation thresholds were also observed from volumetric and refraction properties. The structural phase transitions from w/o-BC -o/w microemulsions could be inferred from the profiles of excess volume vs. ϕ_w, excess refraction vs. ϕ_w and excess molar refraction vs. ϕ_w.r ratio (wo) in the reverse micelles and microemulsions. Turbidity, viscosity and surface tension plotted against fW show unusual patterns with increasing fW indicating different microstructures in microemulsions and reverse micelles. Percolation theory was applied on conductivity results to identify microstructures of microemulsions and reverse micelles. The conductivity values show percolation thresholds (fC) which correlate well with viscosity, turbidity and surface tension results. The micostructural changes from water-in-oil (w/o) to bicontinuous (BC), fC1 and BC to oil-in-water (o/w), fC2 give rise to phase transitions in percolation thresholds in the microemulsions. Phase transitions at these percolation thresholds were also observed from volumetric and refraction properties. The structural phase transitions from w/o-BC -o/w microemulsions could be inferred from the profiles of excess volume vs. fW, excess refraction vs. fW and excess molar refraction vs. fW.
Reverse micelles and microemulsions of cetyltrymethylammonium bromide (CTAB) have been prepared over a wide range of compositions and the physicochemical properties have been studied in detail. Conductivity and density increase, while the refractive index decreases with increasing volume fraction of water (fW) or water to surfactant molaReverse micelles and microemulsions of cetyltrymethylammonium bromide (CTAB) have been prepared over a wide range of compositions and the physicochemical properties have been studied in detail. Conductivity and density increase, while the refractive index decreases with increasing volume fraction of water (ϕ_w) or water to surfactant molar ratio (w_0) in the reverse micelles and microemulsions. Turbidity, viscosity and surface tension plotted against ϕ_w show unusual patterns with increasing ϕ_w indicating different microstructures in microemulsions and reverse micelles. Percolation theory was applied on conductivity results to identify microstructures of microemulsions and reverse micelles. The conductivity values show percolation thresholds (ϕ_c)which correlate well with viscosity, turbidity and surface tension results. The micostructural changes from water-in-oil (w/o) to bicontinuous (BC), ϕ_C1 and BC to oil-in-water (o/w), ϕ_C2 give rise to phase transitions in percolation thresholds in the microemulsions. Phase transitions at these percolation thresholds were also observed from volumetric and refraction properties. The structural phase transitions from w/o-BC -o/w microemulsions could be inferred from the profiles of excess volume vs. ϕ_w, excess refraction vs. ϕ_w and excess molar refraction vs. ϕ_w.r ratio (wo) in the reverse micelles and microemulsions. Turbidity, viscosity and surface tension plotted against fW show unusual patterns with increasing fW indicating different microstructures in microemulsions and reverse micelles. Percolation theory was applied on conductivity results to identify microstructures of microemulsions and reverse micelles. The conductivity values show percolation thresholds (fC) which correlate well with viscosity, turbidity and surface tension results. The micostructural changes from water-in-oil (w/o) to bicontinuous (BC), fC1 and BC to oil-in-water (o/w), fC2 give rise to phase transitions in percolation thresholds in the microemulsions. Phase transitions at these percolation thresholds were also observed from volumetric and refraction properties. The structural phase transitions from w/o-BC -o/w microemulsions could be inferred from the profiles of excess volume vs. fW, excess refraction vs. fW and excess molar refraction vs. fW.
Restricted
Abstract
Purification of heavy water used as the moderator and coolant of pressurized heavy water nuclear reactors (PHWRs) is a vital step in ensuring its adequate isotopic content that maintains neutron economy in the reactor core. This process is carried out in a packed vacuum distillation column which requires condensers and reboilers as essential heat transfer components. A vertical thermosiphon reboiler is used to minimize operating costs of the distillation system by eliminating the fluid recirculation pump and improving system reliability and safety by minimizing leakages and heavy water losses. This work presents a simple, direct methodology for optimizing the design and operation of such a reboiler using codes developed in-house and based on heuristics and two-phase heat and momentum transfer correlations from literature. The methodology is general and can be applied to any application requiring a thermosiphon reboiler. Parametric analysis and cost calculations have also been performed along with exergy analysis of reboiler performance.
Purification of heavy water used as the moderator and coolant of pressurized heavy water nuclear reactors (PHWRs) is a vital step in ensuring its adequate isotopic content that maintains neutron economy in the reactor core. This process is carried out in a packed vacuum distillation column which requires condensers and reboilers as essential heat transfer components. A vertical thermosiphon reboiler is used to minimize operating costs of the distillation system by eliminating the fluid recirculation pump and improving system reliability and safety by minimizing leakages and heavy water losses. This work presents a simple, direct methodology for optimizing the design and operation of such a reboiler using codes developed in-house and based on heuristics and two-phase heat and momentum transfer correlations from literature. The methodology is general and can be applied to any application requiring a thermosiphon reboiler. Parametric analysis and cost calculations have also been performed along with exergy analysis of reboiler performance.
Restricted