This document discusses using the sodium sulfite oxidation method and response surface methodology to evaluate the volumetric mass transfer coefficient in a lab-scale fermenter. 13 experiments were conducted using a central composite design to determine the effects of impeller speed and airflow rate on the mass transfer coefficient. An empirical expression was developed and found to explain over 92% of the variability in the responses. The mass transfer coefficient was found to increase with decreasing impeller speed and increasing airflow rate. The study aimed to optimize the mass transfer coefficient using statistical experimental design.
Measurement of mass transfer coefficient (k la) Ashok Shinde
The document discusses measurement of the volumetric mass transfer coefficient (KLa), which indicates the rate of oxygen transfer in a bioreactor. It describes various methods to determine KLa values, including chemical and physical techniques like the sodium sulphite oxidation method. The document also covers factors that affect KLa, and how KLa values are used to scale bioreactors from laboratory to production scale.
This document discusses gas transfer, which is the physical phenomenon of gas molecules being exchanged between a liquid and gas at their interface. This leads to gas being absorbed into or released from the liquid phase. Important examples of natural gas transfer include the reaeration of surface water through the transfer of oxygen, release of gases produced by algae, and release of contaminants. Several factors control the exchange of dissolved compounds between water and air, including mixing, surface area, temperature, and concentrations in each phase. The document outlines various elements of aeration and gas transfer operations like diffused aerators, mechanical aerators, and factors that influence gas solubility such as temperature, gas concentration, and impurities. It also discusses concepts like Henry
Mass transfer coefficient evaluation for lab scale fermenter using sodium sul...Alexander Decker
This document discusses using the sodium sulfite oxidation method and response surface methodology to evaluate the volumetric mass transfer coefficient in a lab-scale fermenter. 13 experiments were conducted using a central composite design to determine the effects of impeller speed and airflow rate on the mass transfer coefficient. An empirical expression was developed and found to explain over 92% of the variability in the responses. The mass transfer coefficient was found to increase with decreasing impeller speed and increasing airflow rate. The study aimed to optimize the mass transfer coefficient using statistical experimental design.
11.mass transfer coefficient evaluation for lab scale fermenter using sodium ...Alexander Decker
This document discusses using the sodium sulfite oxidation method and response surface methodology to evaluate the volumetric mass transfer coefficient in a lab-scale fermenter. 13 experiments were conducted using a central composite design to determine the effects of impeller speed and airflow rate on the mass transfer coefficient. An empirical expression was developed and found to explain over 92% of the variability in the responses. The results showed that the mass transfer coefficient increases with decreasing impeller speed and increasing airflow rate. The study aimed to optimize conditions for the maximum mass transfer coefficient.
Chap 1(a) molecular-diffusion_in_gas(2)Charice Wan
The document discusses principles of molecular diffusion in gases. It covers topics such as equimolar counter diffusion, diffusion through cross-sectional areas like spheres, and calculating diffusion coefficients. Examples and problems are provided to demonstrate how to calculate flux and diffusion rates in various scenarios, including diffusion between binary gas mixtures and evaporation from surfaces. Methods for estimating gas diffusivity are also presented.
This document provides an introduction and table of contents to the book "Introduction to Transport Phenomena - Momentum, Heat and Mass" by Bodh Raj. The book covers momentum transfer, heat transfer, and mass transfer phenomena across four main sections. It is intended as an introductory text for undergraduate students and includes solved examples and problems for each chapter.
The document summarizes an experiment studying factors that affect CO2 absorption in a NaOH solution. The experiment tested how absorption is affected by flow rate of CO2 gas, CO2 concentration, volume of NaOH solution, and pH. Absorption increased with lower flow rates, higher NaOH volumes, and higher pH. The results supported theories that more CO2 absorbs at higher pressures and NaOH concentrations. Future studies could optimize flow rates to maximize both absorption capacity and breakthrough time.
Measurement of mass transfer coefficient (k la) Ashok Shinde
The document discusses measurement of the volumetric mass transfer coefficient (KLa), which indicates the rate of oxygen transfer in a bioreactor. It describes various methods to determine KLa values, including chemical and physical techniques like the sodium sulphite oxidation method. The document also covers factors that affect KLa, and how KLa values are used to scale bioreactors from laboratory to production scale.
This document discusses gas transfer, which is the physical phenomenon of gas molecules being exchanged between a liquid and gas at their interface. This leads to gas being absorbed into or released from the liquid phase. Important examples of natural gas transfer include the reaeration of surface water through the transfer of oxygen, release of gases produced by algae, and release of contaminants. Several factors control the exchange of dissolved compounds between water and air, including mixing, surface area, temperature, and concentrations in each phase. The document outlines various elements of aeration and gas transfer operations like diffused aerators, mechanical aerators, and factors that influence gas solubility such as temperature, gas concentration, and impurities. It also discusses concepts like Henry
Mass transfer coefficient evaluation for lab scale fermenter using sodium sul...Alexander Decker
This document discusses using the sodium sulfite oxidation method and response surface methodology to evaluate the volumetric mass transfer coefficient in a lab-scale fermenter. 13 experiments were conducted using a central composite design to determine the effects of impeller speed and airflow rate on the mass transfer coefficient. An empirical expression was developed and found to explain over 92% of the variability in the responses. The mass transfer coefficient was found to increase with decreasing impeller speed and increasing airflow rate. The study aimed to optimize the mass transfer coefficient using statistical experimental design.
11.mass transfer coefficient evaluation for lab scale fermenter using sodium ...Alexander Decker
This document discusses using the sodium sulfite oxidation method and response surface methodology to evaluate the volumetric mass transfer coefficient in a lab-scale fermenter. 13 experiments were conducted using a central composite design to determine the effects of impeller speed and airflow rate on the mass transfer coefficient. An empirical expression was developed and found to explain over 92% of the variability in the responses. The results showed that the mass transfer coefficient increases with decreasing impeller speed and increasing airflow rate. The study aimed to optimize conditions for the maximum mass transfer coefficient.
Chap 1(a) molecular-diffusion_in_gas(2)Charice Wan
The document discusses principles of molecular diffusion in gases. It covers topics such as equimolar counter diffusion, diffusion through cross-sectional areas like spheres, and calculating diffusion coefficients. Examples and problems are provided to demonstrate how to calculate flux and diffusion rates in various scenarios, including diffusion between binary gas mixtures and evaporation from surfaces. Methods for estimating gas diffusivity are also presented.
This document provides an introduction and table of contents to the book "Introduction to Transport Phenomena - Momentum, Heat and Mass" by Bodh Raj. The book covers momentum transfer, heat transfer, and mass transfer phenomena across four main sections. It is intended as an introductory text for undergraduate students and includes solved examples and problems for each chapter.
The document summarizes an experiment studying factors that affect CO2 absorption in a NaOH solution. The experiment tested how absorption is affected by flow rate of CO2 gas, CO2 concentration, volume of NaOH solution, and pH. Absorption increased with lower flow rates, higher NaOH volumes, and higher pH. The results supported theories that more CO2 absorbs at higher pressures and NaOH concentrations. Future studies could optimize flow rates to maximize both absorption capacity and breakthrough time.
This document contains lecture notes on mass transfer operations. It discusses various topics including diffusion, gas-liquid operations like absorption, and vapor-liquid operations like distillation.
The key points covered are:
1) Diffusion is the process of mass transfer between regions of different concentrations due to random molecular motion. Pick's law describes the rate of diffusion.
2) Gas absorption involves the removal of a soluble gas from a mixture by absorption into a liquid. Absorption towers can be analyzed using the concept of gas transfer units.
3) Distillation separates components based on volatility. Batch distillation methods include differential and flash distillation. Continuous rectification in distillation columns can be modeled using material balances
This document summarizes a study that models selective catalytic reduction (SCR) of nitric oxide by ammonia in a fixed-bed reactor using COMSOL Multiphysics software. The model considers a two-dimensional cylindrical reactor geometry and couples equations for mass and momentum transport along with the Brinkman equation to account for porosity. Kinetic data from literature was used and conversions were calculated from concentration results. Model results were within 5% of experimental data, validating the model. A parametric study examined the effects of reactant concentrations, temperature, water content, and porosity on conversion percentages.
The document summarizes a gas absorption experiment that analyzed the effect of various factors on the overall mass transfer coefficient (KLa) and absorption rate (Ra) of CO2. The experiment measured physical absorption using water and chemical absorption using an NaOH solution, varying liquid flow rates and gas composition. Results showed KLa and Ra were greater with higher liquid flows and CO2 concentration. Chemical absorption and higher temperatures produced better absorption. Recommendations included relocating the liquid feed bucket for easier access and conducting more runs.
Presentation of 2 datasets of H2 and its isotopic composition:
- Time series from six background stations
- Dataset collected in the UTLS with a commercial aircraft
Transfer velocities for a suite of trace gases of emerging biogeochemical im...Martin Johnson
Authors M. T. Johnson, P. S. Liss, T.G. Bell and C.Hughes and J. Woeltjen
Paper given at the 6th International Symposium on Gas Transfer at Water Surfaces, Kyoto, Japan, May 2010.
Calculating the air-sea flux of any trace gas: transfer velocity, chemical e...Martin Johnson
This document discusses methods for calculating the air-sea flux of trace gases, including accounting for chemical enhancement effects. It describes the two-layer model of gas exchange and parameters that influence transfer velocities in the air and water phases, such as wind speed, temperature, solubility, and gas diffusion rates. The document also addresses sources of uncertainty in flux calculations and situations where chemical reactions in water may enhance or inhibit gas transfer rates relative to classical models.
Experiments in transport phenomena crosbyNoe Nunez
This document discusses the need for experimentation in chemical engineering. It notes that while theoretical models can be developed using principles of transport phenomena, these models contain physical properties that must be determined experimentally. For complex systems or turbulent flow, empirical models are needed to characterize transport rates, and the actual relationships between operating conditions and transport coefficients must be experimentally determined. The purpose of the experiments in this course is to demonstrate that transport phenomena quantities can be measured and help students recognize the connection between theoretical concepts and practical applications.
This document provides an overview of Darcy's law and permeability concepts covered in a reservoir engineering course. It begins by defining permeability as a property that controls fluid flow in porous media. Darcy's law is then introduced, which relates fluid flow rate to pressure drop, permeability, fluid properties, and geometry. The document goes on to discuss permeability measurement techniques, effective and relative permeability, reservoir properties, heterogeneity, and applications of Darcy's law to linear and radial flow models.
This document summarizes various methods for analyzing coning behavior and predicting breakthrough time in horizontal wells producing from reservoirs with bottom water or gas caps. It discusses correlations from Chaperson, Efros, Karcher and Ozkan-Raghavan for determining critical production rates and the factors they account for, as well as Ozkan-Raghavan's method for calculating breakthrough time using dimensionless parameters and a sweep efficiency correlation. The document is from a reservoir engineering course covering these analytical methods for modeling coning problems in horizontal wells.
The document summarizes research on oxygen mass transfer in a bubble column with non-Newtonian fluids. Xanthan gum solutions were used to simulate activated sludge viscosity. Clean water tests were conducted with different airflow rates and Xanthan gum concentrations. The results showed that increasing fluid viscosity through higher Xanthan gum concentration decreased oxygen transfer rates, but this could be offset by increasing airflow rates. Higher airflow increased shear and disrupted flocs, decreasing viscosity and improving oxygen transfer.
This document discusses aeration and agitation in fermentation processes. It describes how oxygen is supplied to microbial cultures through aeration, which involves bubbling air through the liquid or agitating the liquid to increase oxygen absorption. Key factors that influence oxygen transfer rates include the agitator, baffles, aeration system, dissolved oxygen concentration, volumetric mass transfer coefficient (KLa) of the fermenter, and oxygen demand of the microbial culture. Methods for determining the KLa value include the sulphite oxidation technique and gassing out techniques.
This document provides an overview of reservoir engineering concepts related to gas well performance. It discusses different methods for approximating inflow performance relationships (IPRs) for gas wells under various flow regimes, including the pseudosteady state, and accounting for laminar versus turbulent flow. Empirical models are presented for calculating gas flow rates based on reservoir properties, fluid properties, and operating pressures. The document also examines pressure regions and appropriate approaches for each, such as using real gas pseudopressure or a pressure-squared method at low pressures.
This document provides an overview of a reservoir engineering course covering topics like:
- PSS and skin concepts for radial flow of single- and multi-phase fluids
- Turbulent versus laminar flow and models for turbulent/non-Darcy flow
- The concept of superposition and its applications, including effects of multiple wells, rate changes, boundaries, and pressure changes
- Transient well testing methods and the information they provide about a reservoir's properties
The document discusses how nitrogen, helium, and hydrogen have different plots according to the Van Deemter equation. It analyzes the A, B, and C terms in the equation. For term A, nitrogen has the lowest value and helium has the highest because nitrogen moves slowest in the column. For term B, hydrogen has the highest value and nitrogen the lowest because diffusion decreases with increasing carrier gas density. For term C, hydrogen has the lowest value and nitrogen the highest because resistance to mass transfer decreases with decreasing carrier gas density.
This document summarizes key topics in reservoir engineering related to gas well performance and driving mechanisms. It covers turbulent gas flow models including the laminar-inertial-turbulent approach and pseudopressure method. It also discusses calculating inflow performance relationships, predicting future IPRs, modeling horizontal gas wells, and the primary recovery mechanisms of depletion drive, gas cap drive, water drive, and combination drive.
This document provides an overview of a reservoir engineering course focused on Darcy's Law and permeability. It covers key topics like laboratory analysis of rock properties including porosity, saturation and permeability. It also discusses linear and radial flow models based on Darcy's Law and techniques for determining permeability in the laboratory and averaging permeabilities for heterogeneous reservoirs. The document emphasizes that permeability is an important property that controls fluid flow in reservoirs and was first mathematically defined by Henry Darcy. It provides the equations for linear and radial flow based on Darcy's Law.
This study evaluated the mass transfer coefficient (Kma) and equilibrium distillation coefficient (Kd) of propionic acid (PA) extracted from n-propyl bromide (NPB) into water using a continuous counter-current liquid-liquid extraction column. Experiments were conducted at different water flow rates of 0.15, 0.20, 0.25, and 0.31 L/min. The results showed that steady state fractional conversions were unaffected by flow rate and that increasing water flow rate linearly increased Kma. Calculated Kma values were 0.0023, 0.0035, and 0.0046 1/sec for water flows of 0.15, 0.20, and 0.31 L
The document discusses laboratory analysis techniques for gas condensate systems, including recombination and analysis of separator samples, constant-composition expansion tests, and constant-volume depletion tests. It describes the procedures for these various laboratory experiments in detail, including determining fluid properties like compressibility factors and calculating quantities like retrograde liquid saturation and cumulative gas production. The goal is to better understand the pressure-volume-temperature behavior and compositional changes that occur during depletion of a gas condensate reservoir.
The document discusses various analogies that can be drawn between the transport processes of momentum, heat, and mass. It explains that the basic transport mechanisms are the same and the governing equations are identical in form. Various analogies are presented, including the Reynolds analogy and modifications by Prandtl and von Korman that account for viscous sublayers and buffer layers in turbulent transport.
Slides for the eLearning course Separation and purification processes in biorefineries (https://open-learn.xamk.fi) in IMPRESS project (https://www.spire2030.eu/impress).
Section: Crystallization
Subject: 1.5 Phase equilibrium
IRJET- Mass Transfer Performance of Al2O3 Nanofluids for CO2 Absorption in a ...IRJET Journal
This document summarizes a study on the mass transfer performance of Al2O3 nanofluids for CO2 absorption in a wetted wall column. The researchers prepared Al2O3/water nanofluids with 0.2-1.0% volume fractions of Al2O3 nanoparticles. Experiments were conducted in a wetted wall column under counter-current gas-liquid flow of CO2 and the nanofluids. The molar flux of CO2 absorption increased with higher nanoparticle concentrations and gas flow rates. The maximum enhancement in molar flux occurred at a nanoparticle concentration of 0.6% volume fraction across all gas flow rates tested of 30, 40 and 50 LPH. The improved mass transfer is attributed
This document provides an overview of airflow in acid-generating waste rock dumps. There are three main mechanisms of airflow - diffusion, convection, and barometric pumping. Diffusion transports oxygen through concentration gradients but is limited to shallow depths. Convection occurs due to thermal or pressure gradients and can transport oxygen deeper. Barometric pumping moves air in response to atmospheric pressure changes. Understanding airflow is important to control acid rock drainage generation from waste rock.
This document contains lecture notes on mass transfer operations. It discusses various topics including diffusion, gas-liquid operations like absorption, and vapor-liquid operations like distillation.
The key points covered are:
1) Diffusion is the process of mass transfer between regions of different concentrations due to random molecular motion. Pick's law describes the rate of diffusion.
2) Gas absorption involves the removal of a soluble gas from a mixture by absorption into a liquid. Absorption towers can be analyzed using the concept of gas transfer units.
3) Distillation separates components based on volatility. Batch distillation methods include differential and flash distillation. Continuous rectification in distillation columns can be modeled using material balances
This document summarizes a study that models selective catalytic reduction (SCR) of nitric oxide by ammonia in a fixed-bed reactor using COMSOL Multiphysics software. The model considers a two-dimensional cylindrical reactor geometry and couples equations for mass and momentum transport along with the Brinkman equation to account for porosity. Kinetic data from literature was used and conversions were calculated from concentration results. Model results were within 5% of experimental data, validating the model. A parametric study examined the effects of reactant concentrations, temperature, water content, and porosity on conversion percentages.
The document summarizes a gas absorption experiment that analyzed the effect of various factors on the overall mass transfer coefficient (KLa) and absorption rate (Ra) of CO2. The experiment measured physical absorption using water and chemical absorption using an NaOH solution, varying liquid flow rates and gas composition. Results showed KLa and Ra were greater with higher liquid flows and CO2 concentration. Chemical absorption and higher temperatures produced better absorption. Recommendations included relocating the liquid feed bucket for easier access and conducting more runs.
Presentation of 2 datasets of H2 and its isotopic composition:
- Time series from six background stations
- Dataset collected in the UTLS with a commercial aircraft
Transfer velocities for a suite of trace gases of emerging biogeochemical im...Martin Johnson
Authors M. T. Johnson, P. S. Liss, T.G. Bell and C.Hughes and J. Woeltjen
Paper given at the 6th International Symposium on Gas Transfer at Water Surfaces, Kyoto, Japan, May 2010.
Calculating the air-sea flux of any trace gas: transfer velocity, chemical e...Martin Johnson
This document discusses methods for calculating the air-sea flux of trace gases, including accounting for chemical enhancement effects. It describes the two-layer model of gas exchange and parameters that influence transfer velocities in the air and water phases, such as wind speed, temperature, solubility, and gas diffusion rates. The document also addresses sources of uncertainty in flux calculations and situations where chemical reactions in water may enhance or inhibit gas transfer rates relative to classical models.
Experiments in transport phenomena crosbyNoe Nunez
This document discusses the need for experimentation in chemical engineering. It notes that while theoretical models can be developed using principles of transport phenomena, these models contain physical properties that must be determined experimentally. For complex systems or turbulent flow, empirical models are needed to characterize transport rates, and the actual relationships between operating conditions and transport coefficients must be experimentally determined. The purpose of the experiments in this course is to demonstrate that transport phenomena quantities can be measured and help students recognize the connection between theoretical concepts and practical applications.
This document provides an overview of Darcy's law and permeability concepts covered in a reservoir engineering course. It begins by defining permeability as a property that controls fluid flow in porous media. Darcy's law is then introduced, which relates fluid flow rate to pressure drop, permeability, fluid properties, and geometry. The document goes on to discuss permeability measurement techniques, effective and relative permeability, reservoir properties, heterogeneity, and applications of Darcy's law to linear and radial flow models.
This document summarizes various methods for analyzing coning behavior and predicting breakthrough time in horizontal wells producing from reservoirs with bottom water or gas caps. It discusses correlations from Chaperson, Efros, Karcher and Ozkan-Raghavan for determining critical production rates and the factors they account for, as well as Ozkan-Raghavan's method for calculating breakthrough time using dimensionless parameters and a sweep efficiency correlation. The document is from a reservoir engineering course covering these analytical methods for modeling coning problems in horizontal wells.
The document summarizes research on oxygen mass transfer in a bubble column with non-Newtonian fluids. Xanthan gum solutions were used to simulate activated sludge viscosity. Clean water tests were conducted with different airflow rates and Xanthan gum concentrations. The results showed that increasing fluid viscosity through higher Xanthan gum concentration decreased oxygen transfer rates, but this could be offset by increasing airflow rates. Higher airflow increased shear and disrupted flocs, decreasing viscosity and improving oxygen transfer.
This document discusses aeration and agitation in fermentation processes. It describes how oxygen is supplied to microbial cultures through aeration, which involves bubbling air through the liquid or agitating the liquid to increase oxygen absorption. Key factors that influence oxygen transfer rates include the agitator, baffles, aeration system, dissolved oxygen concentration, volumetric mass transfer coefficient (KLa) of the fermenter, and oxygen demand of the microbial culture. Methods for determining the KLa value include the sulphite oxidation technique and gassing out techniques.
This document provides an overview of reservoir engineering concepts related to gas well performance. It discusses different methods for approximating inflow performance relationships (IPRs) for gas wells under various flow regimes, including the pseudosteady state, and accounting for laminar versus turbulent flow. Empirical models are presented for calculating gas flow rates based on reservoir properties, fluid properties, and operating pressures. The document also examines pressure regions and appropriate approaches for each, such as using real gas pseudopressure or a pressure-squared method at low pressures.
This document provides an overview of a reservoir engineering course covering topics like:
- PSS and skin concepts for radial flow of single- and multi-phase fluids
- Turbulent versus laminar flow and models for turbulent/non-Darcy flow
- The concept of superposition and its applications, including effects of multiple wells, rate changes, boundaries, and pressure changes
- Transient well testing methods and the information they provide about a reservoir's properties
The document discusses how nitrogen, helium, and hydrogen have different plots according to the Van Deemter equation. It analyzes the A, B, and C terms in the equation. For term A, nitrogen has the lowest value and helium has the highest because nitrogen moves slowest in the column. For term B, hydrogen has the highest value and nitrogen the lowest because diffusion decreases with increasing carrier gas density. For term C, hydrogen has the lowest value and nitrogen the highest because resistance to mass transfer decreases with decreasing carrier gas density.
This document summarizes key topics in reservoir engineering related to gas well performance and driving mechanisms. It covers turbulent gas flow models including the laminar-inertial-turbulent approach and pseudopressure method. It also discusses calculating inflow performance relationships, predicting future IPRs, modeling horizontal gas wells, and the primary recovery mechanisms of depletion drive, gas cap drive, water drive, and combination drive.
This document provides an overview of a reservoir engineering course focused on Darcy's Law and permeability. It covers key topics like laboratory analysis of rock properties including porosity, saturation and permeability. It also discusses linear and radial flow models based on Darcy's Law and techniques for determining permeability in the laboratory and averaging permeabilities for heterogeneous reservoirs. The document emphasizes that permeability is an important property that controls fluid flow in reservoirs and was first mathematically defined by Henry Darcy. It provides the equations for linear and radial flow based on Darcy's Law.
This study evaluated the mass transfer coefficient (Kma) and equilibrium distillation coefficient (Kd) of propionic acid (PA) extracted from n-propyl bromide (NPB) into water using a continuous counter-current liquid-liquid extraction column. Experiments were conducted at different water flow rates of 0.15, 0.20, 0.25, and 0.31 L/min. The results showed that steady state fractional conversions were unaffected by flow rate and that increasing water flow rate linearly increased Kma. Calculated Kma values were 0.0023, 0.0035, and 0.0046 1/sec for water flows of 0.15, 0.20, and 0.31 L
The document discusses laboratory analysis techniques for gas condensate systems, including recombination and analysis of separator samples, constant-composition expansion tests, and constant-volume depletion tests. It describes the procedures for these various laboratory experiments in detail, including determining fluid properties like compressibility factors and calculating quantities like retrograde liquid saturation and cumulative gas production. The goal is to better understand the pressure-volume-temperature behavior and compositional changes that occur during depletion of a gas condensate reservoir.
The document discusses various analogies that can be drawn between the transport processes of momentum, heat, and mass. It explains that the basic transport mechanisms are the same and the governing equations are identical in form. Various analogies are presented, including the Reynolds analogy and modifications by Prandtl and von Korman that account for viscous sublayers and buffer layers in turbulent transport.
Slides for the eLearning course Separation and purification processes in biorefineries (https://open-learn.xamk.fi) in IMPRESS project (https://www.spire2030.eu/impress).
Section: Crystallization
Subject: 1.5 Phase equilibrium
IRJET- Mass Transfer Performance of Al2O3 Nanofluids for CO2 Absorption in a ...IRJET Journal
This document summarizes a study on the mass transfer performance of Al2O3 nanofluids for CO2 absorption in a wetted wall column. The researchers prepared Al2O3/water nanofluids with 0.2-1.0% volume fractions of Al2O3 nanoparticles. Experiments were conducted in a wetted wall column under counter-current gas-liquid flow of CO2 and the nanofluids. The molar flux of CO2 absorption increased with higher nanoparticle concentrations and gas flow rates. The maximum enhancement in molar flux occurred at a nanoparticle concentration of 0.6% volume fraction across all gas flow rates tested of 30, 40 and 50 LPH. The improved mass transfer is attributed
This document provides an overview of airflow in acid-generating waste rock dumps. There are three main mechanisms of airflow - diffusion, convection, and barometric pumping. Diffusion transports oxygen through concentration gradients but is limited to shallow depths. Convection occurs due to thermal or pressure gradients and can transport oxygen deeper. Barometric pumping moves air in response to atmospheric pressure changes. Understanding airflow is important to control acid rock drainage generation from waste rock.
This document discusses factors related to oxygen transfer in bioreactors. It covers oxygen demand based on microbial physiology and respiration rates. It also discusses factors that influence oxygen supply, including process parameters, mass transfer through gas-liquid interfaces, methods for determining the mass transfer coefficient (KLa), factors affecting bubble size, gas holdup, and economics of oxygen transfer. The key goal is balancing oxygen demand by microbes and oxygen supply capabilities of the bioreactor system.
This document discusses gas liquid mass transfer in bioreactors. It provides an introduction to bioreactors and their importance in producing bio-based products. It explains that gas concentrations are maintained through optimized gas liquid mass transfer and mixing. The document surveys gas liquid mass transfer theories and applications in batch bioreactors and bubble column bioreactors. The objective is to compare gas liquid mass transfer in these two bioreactor types and optimize it using artificial intelligence. Equations for oxygen transfer rate and volumetric mass transfer coefficient are also presented.
Wet oxidation is a hydrothermal treatment of aqueous solutions of biologically
recalcitrant and hazardous chemicals/wastes. It is the oxidation of dissolved or suspended
matter in water using an oxidant such as ozone, oxygen, hydrogen peroxide, air etc. It is
referred to as Wet Air Oxidation (WAO) when air is used as an oxidant. The oxidation
reactions generally occur at temperatures above the normal boiling point of water (100
°C) but below its critical point (374 °C). The system must also be maintained under
pressure i) to maintain the solution in liquid form; ii) to avoid excessive evaporation of
water and also iii) to conserve energy, as the evaporation needs latent heat of
vaporization. Under wet conditions, many compounds get oxidized which would
otherwise not oxidize under dry (not wet) conditions, even at the same temperature and
pressure.
Numerical Simulation of Theories for Gas Absorption with Chemical Reactionptnk triz
This document discusses several theories for modeling gas absorption with chemical reaction, including film theory, penetration theory, surface renewal theory, and eddy diffusivity theory. It also presents numerical solutions of the governing equations for these theories applied to a second-order reversible reaction and the absorption of CO2 into aqueous MDEA. Comparisons of predicted absorption enhancement factors are made between the theories. The applicability of approximate solution methods is also discussed.
Oxidacion de etano a etileno y acido acetico con catalizadores MoVCarlos Timaná
This document discusses kinetics and mechanisms of partial oxidation of ethane to ethylene and acetic acid over molybdenum-vanadium (MoV) type catalysts. It provides background on previous studies that have suggested multi-phase catalysts are needed and that there are two catalytic sites, one for ethane oxidation and another for ethylene oxidation to acetic acid. The document then presents results of a new kinetics study investigating the effects of adding water to the feed on product formation. A reaction mechanism is proposed incorporating water participation through surface OH groups. A kinetic model is developed based on this new mechanism that satisfactorily predicts experimental results.
Wet air oxidation is a process that uses air as an oxidant to oxidize hazardous organic chemicals and wastes in an aqueous solution at elevated temperatures and pressures. It is more energy efficient than incineration and can fully mineralize wastes into carbon dioxide, water, and inorganic salts. The wet air oxidation process involves two main stages - a physical stage of oxygen transfer from the gas to liquid phase, and a chemical stage of free radical reactions between oxygen and organic compounds. Kinetics studies show the reaction rate depends on temperature, oxygen pressure, and organic compound concentration. Catalysts can significantly reduce the operating conditions required by improving chemical reaction rates.
Arsenic removal by adsorption on activated carbon in a rotating packed bedSoumyadeep Mukherjee
This document summarizes a study that used a rotating packed bed contactor to optimize the removal of arsenic from water using activated carbon adsorption. Five parameters were investigated using Taguchi method to determine the optimal conditions: rotating speed, feed rate, packing density, initial arsenic concentration, and initial pH. The optimal conditions found were a rotating speed of 1600 rpm, feed rate of 50 L/h, packing density of 510 kg/m3, initial concentration of 150 mg/L, and pH of 3 based on the highest signal to noise ratio. The initial concentration was found to be the least affecting factor.
The document discusses rate of reaction and factors that affect it. It defines rate of reaction as the change in amount of reactants or products per unit time. Rate of reaction is affected by several factors including surface area, concentration, temperature, catalysts and pressure (for gas reactions). The collision theory is also explained, stating that reactions only occur during effective collisions where particles attain sufficient kinetic energy to overcome the activation energy barrier. Examples of how scientific understanding of rate of reaction enhances quality of life through applications like food storage, cooking and petroleum processing are provided.
This paper studied the competitive adsorption of nitrate and oxalic acid on TiO2. It found that while nitrate had a higher Langmuir adsorption coefficient, oxalic acid adsorbed about 10 times more due to its ability to bind in two ways. In competitive adsorption, oxalic acid preferentially adsorbed, inhibiting nitrate uptake by up to 93% at higher oxalic acid concentrations. This inhibition could reduce the effectiveness of photocatalytic nitrate remediation, suggesting surface modification may be needed to enhance nitrate adsorption for faster reaction rates.
“Kinetics and mechanism of sulphuric acid oxidation of glycolic (ga) by selen...آفتاب حسین
This document provides an introduction to a study on the kinetics and mechanism of the oxidation of glycolic acid by selenium dioxide in an aqueous-acid medium. It discusses background information on chemical kinetics, oxidation-reduction reactions, and selenium dioxide as an oxidizing agent. Previous studies on the oxidation of various compounds like ketones using selenium dioxide are also summarized. The document lays out context for investigating the reaction kinetics and mechanism of glycolic acid oxidation.
The document discusses rate of reaction and factors that affect it. It defines rate of reaction as the change in amount of reactants or products per unit time. It describes several factors that affect rate based on collision theory, including surface area, concentration, temperature, catalysts, and pressure. It gives examples of how scientific understanding of rate of reaction enhances quality of life, such as refrigeration, pressure cooking, cutting food into smaller pieces, making margarine, and burning coal.
This document summarizes a study on using a triphasic segmented flow millireactor for rapid nanoparticle-catalyzed gas-liquid reactions with facile catalyst recovery. Key points:
- The millireactor creates a pseudo-biphasic gas-liquid segmented flow using an aqueous catalyst phase and an organic substrate/product phase, allowing order-of-magnitude faster reactions than a batch reactor.
- For the hydrogenation of 1-hexene catalyzed by Rh nanoparticles, the millireactor achieves 80% conversion in 1 minute versus 30 minutes for a batch reactor.
- Faster mass transfer in the millireactor is achieved by reducing the diffusion distance for reactants through thinner organic segments at
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
This document summarizes a study that measured the kinetics of carbon dioxide absorption into aqueous solutions of lithium, sodium, and potassium hydroxides and blends of hydroxides and carbonates over a range of temperatures and concentrations. The researchers derived an infinite dilution second order rate constant for the reaction of carbon dioxide with hydroxide ions as an Arrhenius temperature function. They also validated a model for the ionic strength dependency of the second order rate constant using refitted parameters. The model with the new parameters represented the experimental data with less than 12% average absolute relative deviation.
An insight into spray pulsed reactor through mathematical modeling of catalyt...Siluvai Antony Praveen
This document presents a mathematical model developed to study the impact of nozzle-catalyst distance and bulk gas temperature on the conversion and hydrogen evolution rate in a spray pulse reactor for the catalytic dehydrogenation of cyclohexane. The model was able to predict the effects of reactor configuration and operating parameters on conversion and evolution rate with over 90% accuracy. Reactor optimization analysis identified an optimal design of 5 cm nozzle-catalyst distance and 50°C bulk gas temperature, which was predicted to increase conversion from approximately 32% to 74%. The model provides a means to design endothermic heterogeneous catalytic reactions in spray pulse reactors.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability.
This document provides an overview of mathematical modelling of streams. It discusses the need for modelling to simulate different water quality scenarios and management strategies. It introduces various types of mathematical models and describes the governing laws and equations used in water quality models. Key aspects covered include modelling of dissolved oxygen levels using the Streeter-Phelps model, and a case study applying the QUAL2Kw model to a river in Karnataka, India.
This document presents a comparative study of the performance of activated sludge processes in a bubble column reactor and compact jet loop reactor. Experiments were conducted using synthetic wastewater in laboratory scale models of each reactor type. The chemical oxygen demand (COD) removal efficiency was measured at different mixed liquor volatile suspended solids (MLVSS) concentrations and hydraulic retention times. The results showed that a COD removal efficiency of over 85% could be achieved in the bubble column reactor, and over 95% in the compact jet loop reactor, when operated at an MLVSS of 3000 mg/L and aeration time of 1 hour. The compact jet loop reactor demonstrated better COD reduction performance than the bubble column reactor under the conditions tested.
Similar to Mass transfer coefficient evaluation for lab scale fermenter using sodium sulphite oxidation method (20)
Abnormalities of hormones and inflammatory cytokines in women affected with p...Alexander Decker
Women with polycystic ovary syndrome (PCOS) have elevated levels of hormones like luteinizing hormone and testosterone, as well as higher levels of insulin and insulin resistance compared to healthy women. They also have increased levels of inflammatory markers like C-reactive protein, interleukin-6, and leptin. This study found these abnormalities in the hormones and inflammatory cytokines of women with PCOS ages 23-40, indicating that hormone imbalances associated with insulin resistance and elevated inflammatory markers may worsen infertility in women with PCOS.
A usability evaluation framework for b2 c e commerce websitesAlexander Decker
This document presents a framework for evaluating the usability of B2C e-commerce websites. It involves user testing methods like usability testing and interviews to identify usability problems in areas like navigation, design, purchasing processes, and customer service. The framework specifies goals for the evaluation, determines which website aspects to evaluate, and identifies target users. It then describes collecting data through user testing and analyzing the results to identify usability problems and suggest improvements.
A universal model for managing the marketing executives in nigerian banksAlexander Decker
This document discusses a study that aimed to synthesize motivation theories into a universal model for managing marketing executives in Nigerian banks. The study was guided by Maslow and McGregor's theories. A sample of 303 marketing executives was used. The results showed that managers will be most effective at motivating marketing executives if they consider individual needs and create challenging but attainable goals. The emerged model suggests managers should provide job satisfaction by tailoring assignments to abilities and monitoring performance with feedback. This addresses confusion faced by Nigerian bank managers in determining effective motivation strategies.
A unique common fixed point theorems in generalized dAlexander Decker
This document presents definitions and properties related to generalized D*-metric spaces and establishes some common fixed point theorems for contractive type mappings in these spaces. It begins by introducing D*-metric spaces and generalized D*-metric spaces, defines concepts like convergence and Cauchy sequences. It presents lemmas showing the uniqueness of limits in these spaces and the equivalence of different definitions of convergence. The goal of the paper is then stated as obtaining a unique common fixed point theorem for generalized D*-metric spaces.
A trends of salmonella and antibiotic resistanceAlexander Decker
This document provides a review of trends in Salmonella and antibiotic resistance. It begins with an introduction to Salmonella as a facultative anaerobe that causes nontyphoidal salmonellosis. The emergence of antimicrobial-resistant Salmonella is then discussed. The document proceeds to cover the historical perspective and classification of Salmonella, definitions of antimicrobials and antibiotic resistance, and mechanisms of antibiotic resistance in Salmonella including modification or destruction of antimicrobial agents, efflux pumps, modification of antibiotic targets, and decreased membrane permeability. Specific resistance mechanisms are discussed for several classes of antimicrobials.
A transformational generative approach towards understanding al-istifhamAlexander Decker
This document discusses a transformational-generative approach to understanding Al-Istifham, which refers to interrogative sentences in Arabic. It begins with an introduction to the origin and development of Arabic grammar. The paper then explains the theoretical framework of transformational-generative grammar that is used. Basic linguistic concepts and terms related to Arabic grammar are defined. The document analyzes how interrogative sentences in Arabic can be derived and transformed via tools from transformational-generative grammar, categorizing Al-Istifham into linguistic and literary questions.
A time series analysis of the determinants of savings in namibiaAlexander Decker
This document summarizes a study on the determinants of savings in Namibia from 1991 to 2012. It reviews previous literature on savings determinants in developing countries. The study uses time series analysis including unit root tests, cointegration, and error correction models to analyze the relationship between savings and variables like income, inflation, population growth, deposit rates, and financial deepening in Namibia. The results found inflation and income have a positive impact on savings, while population growth negatively impacts savings. Deposit rates and financial deepening were found to have no significant impact. The study reinforces previous work and emphasizes the importance of improving income levels to achieve higher savings rates in Namibia.
A therapy for physical and mental fitness of school childrenAlexander Decker
This document summarizes a study on the importance of exercise in maintaining physical and mental fitness for school children. It discusses how physical and mental fitness are developed through participation in regular physical exercises and cannot be achieved solely through classroom learning. The document outlines different types and components of fitness and argues that developing fitness should be a key objective of education systems. It recommends that schools ensure pupils engage in graded physical activities and exercises to support their overall development.
A theory of efficiency for managing the marketing executives in nigerian banksAlexander Decker
This document summarizes a study examining efficiency in managing marketing executives in Nigerian banks. The study was examined through the lenses of Kaizen theory (continuous improvement) and efficiency theory. A survey of 303 marketing executives from Nigerian banks found that management plays a key role in identifying and implementing efficiency improvements. The document recommends adopting a "3H grand strategy" to improve the heads, hearts, and hands of management and marketing executives by enhancing their knowledge, attitudes, and tools.
This document discusses evaluating the link budget for effective 900MHz GSM communication. It describes the basic parameters needed for a high-level link budget calculation, including transmitter power, antenna gains, path loss, and propagation models. Common propagation models for 900MHz that are described include Okumura model for urban areas and Hata model for urban, suburban, and open areas. Rain attenuation is also incorporated using the updated ITU model to improve communication during rainfall.
A synthetic review of contraceptive supplies in punjabAlexander Decker
This document discusses contraceptive use in Punjab, Pakistan. It begins by providing background on the benefits of family planning and contraceptive use for maternal and child health. It then analyzes contraceptive commodity data from Punjab, finding that use is still low despite efforts to improve access. The document concludes by emphasizing the need for strategies to bridge gaps and meet the unmet need for effective and affordable contraceptive methods and supplies in Punjab in order to improve health outcomes.
A synthesis of taylor’s and fayol’s management approaches for managing market...Alexander Decker
1) The document discusses synthesizing Taylor's scientific management approach and Fayol's process management approach to identify an effective way to manage marketing executives in Nigerian banks.
2) It reviews Taylor's emphasis on efficiency and breaking tasks into small parts, and Fayol's focus on developing general management principles.
3) The study administered a survey to 303 marketing executives in Nigerian banks to test if combining elements of Taylor and Fayol's approaches would help manage their performance through clear roles, accountability, and motivation. Statistical analysis supported combining the two approaches.
A survey paper on sequence pattern mining with incrementalAlexander Decker
This document summarizes four algorithms for sequential pattern mining: GSP, ISM, FreeSpan, and PrefixSpan. GSP is an Apriori-based algorithm that incorporates time constraints. ISM extends SPADE to incrementally update patterns after database changes. FreeSpan uses frequent items to recursively project databases and grow subsequences. PrefixSpan also uses projection but claims to not require candidate generation. It recursively projects databases based on short prefix patterns. The document concludes by stating the goal was to find an efficient scheme for extracting sequential patterns from transactional datasets.
A survey on live virtual machine migrations and its techniquesAlexander Decker
This document summarizes several techniques for live virtual machine migration in cloud computing. It discusses works that have proposed affinity-aware migration models to improve resource utilization, energy efficient migration approaches using storage migration and live VM migration, and a dynamic consolidation technique using migration control to avoid unnecessary migrations. The document also summarizes works that have designed methods to minimize migration downtime and network traffic, proposed a resource reservation framework for efficient migration of multiple VMs, and addressed real-time issues in live migration. Finally, it provides a table summarizing the techniques, tools used, and potential future work or gaps identified for each discussed work.
A survey on data mining and analysis in hadoop and mongo dbAlexander Decker
This document discusses data mining of big data using Hadoop and MongoDB. It provides an overview of Hadoop and MongoDB and their uses in big data analysis. Specifically, it proposes using Hadoop for distributed processing and MongoDB for data storage and input. The document reviews several related works that discuss big data analysis using these tools, as well as their capabilities for scalable data storage and mining. It aims to improve computational time and fault tolerance for big data analysis by mining data stored in Hadoop using MongoDB and MapReduce.
1. The document discusses several challenges for integrating media with cloud computing including media content convergence, scalability and expandability, finding appropriate applications, and reliability.
2. Media content convergence challenges include dealing with the heterogeneity of media types, services, networks, devices, and quality of service requirements as well as integrating technologies used by media providers and consumers.
3. Scalability and expandability challenges involve adapting to the increasing volume of media content and being able to support new media formats and outlets over time.
This document surveys trust architectures that leverage provenance in wireless sensor networks. It begins with background on provenance, which refers to the documented history or derivation of data. Provenance can be used to assess trust by providing metadata about how data was processed. The document then discusses challenges for using provenance to establish trust in wireless sensor networks, which have constraints on energy and computation. Finally, it provides background on trust, which is the subjective probability that a node will behave dependably. Trust architectures need to be lightweight to account for the constraints of wireless sensor networks.
This document discusses private equity investments in Kenya. It provides background on private equity and discusses trends in various regions. The objectives of the study discussed are to establish the extent of private equity adoption in Kenya, identify common forms of private equity utilized, and determine typical exit strategies. Private equity can involve venture capital, leveraged buyouts, or mezzanine financing. Exits allow recycling of capital into new opportunities. The document provides context on private equity globally and in developing markets like Africa to frame the goals of the study.
This document discusses a study that analyzes the financial health of the Indian logistics industry from 2005-2012 using Altman's Z-score model. The study finds that the average Z-score for selected logistics firms was in the healthy to very healthy range during the study period. The average Z-score increased from 2006 to 2010 when the Indian economy was hit by the global recession, indicating the overall performance of the Indian logistics industry was good. The document reviews previous literature on measuring financial performance and distress using ratios and Z-scores, and outlines the objectives and methodology used in the current study.
Building Production Ready Search Pipelines with Spark and MilvusZilliz
Spark is the widely used ETL tool for processing, indexing and ingesting data to serving stack for search. Milvus is the production-ready open-source vector database. In this talk we will show how to use Spark to process unstructured data to extract vector representations, and push the vectors to Milvus vector database for search serving.
Monitoring and Managing Anomaly Detection on OpenShift.pdfTosin Akinosho
Monitoring and Managing Anomaly Detection on OpenShift
Overview
Dive into the world of anomaly detection on edge devices with our comprehensive hands-on tutorial. This SlideShare presentation will guide you through the entire process, from data collection and model training to edge deployment and real-time monitoring. Perfect for those looking to implement robust anomaly detection systems on resource-constrained IoT/edge devices.
Key Topics Covered
1. Introduction to Anomaly Detection
- Understand the fundamentals of anomaly detection and its importance in identifying unusual behavior or failures in systems.
2. Understanding Edge (IoT)
- Learn about edge computing and IoT, and how they enable real-time data processing and decision-making at the source.
3. What is ArgoCD?
- Discover ArgoCD, a declarative, GitOps continuous delivery tool for Kubernetes, and its role in deploying applications on edge devices.
4. Deployment Using ArgoCD for Edge Devices
- Step-by-step guide on deploying anomaly detection models on edge devices using ArgoCD.
5. Introduction to Apache Kafka and S3
- Explore Apache Kafka for real-time data streaming and Amazon S3 for scalable storage solutions.
6. Viewing Kafka Messages in the Data Lake
- Learn how to view and analyze Kafka messages stored in a data lake for better insights.
7. What is Prometheus?
- Get to know Prometheus, an open-source monitoring and alerting toolkit, and its application in monitoring edge devices.
8. Monitoring Application Metrics with Prometheus
- Detailed instructions on setting up Prometheus to monitor the performance and health of your anomaly detection system.
9. What is Camel K?
- Introduction to Camel K, a lightweight integration framework built on Apache Camel, designed for Kubernetes.
10. Configuring Camel K Integrations for Data Pipelines
- Learn how to configure Camel K for seamless data pipeline integrations in your anomaly detection workflow.
11. What is a Jupyter Notebook?
- Overview of Jupyter Notebooks, an open-source web application for creating and sharing documents with live code, equations, visualizations, and narrative text.
12. Jupyter Notebooks with Code Examples
- Hands-on examples and code snippets in Jupyter Notebooks to help you implement and test anomaly detection models.
Taking AI to the Next Level in Manufacturing.pdfssuserfac0301
Read Taking AI to the Next Level in Manufacturing to gain insights on AI adoption in the manufacturing industry, such as:
1. How quickly AI is being implemented in manufacturing.
2. Which barriers stand in the way of AI adoption.
3. How data quality and governance form the backbone of AI.
4. Organizational processes and structures that may inhibit effective AI adoption.
6. Ideas and approaches to help build your organization's AI strategy.
Programming Foundation Models with DSPy - Meetup SlidesZilliz
Prompting language models is hard, while programming language models is easy. In this talk, I will discuss the state-of-the-art framework DSPy for programming foundation models with its powerful optimizers and runtime constraint system.
A Comprehensive Guide to DeFi Development Services in 2024Intelisync
DeFi represents a paradigm shift in the financial industry. Instead of relying on traditional, centralized institutions like banks, DeFi leverages blockchain technology to create a decentralized network of financial services. This means that financial transactions can occur directly between parties, without intermediaries, using smart contracts on platforms like Ethereum.
In 2024, we are witnessing an explosion of new DeFi projects and protocols, each pushing the boundaries of what’s possible in finance.
In summary, DeFi in 2024 is not just a trend; it’s a revolution that democratizes finance, enhances security and transparency, and fosters continuous innovation. As we proceed through this presentation, we'll explore the various components and services of DeFi in detail, shedding light on how they are transforming the financial landscape.
At Intelisync, we specialize in providing comprehensive DeFi development services tailored to meet the unique needs of our clients. From smart contract development to dApp creation and security audits, we ensure that your DeFi project is built with innovation, security, and scalability in mind. Trust Intelisync to guide you through the intricate landscape of decentralized finance and unlock the full potential of blockchain technology.
Ready to take your DeFi project to the next level? Partner with Intelisync for expert DeFi development services today!
Freshworks Rethinks NoSQL for Rapid Scaling & Cost-EfficiencyScyllaDB
Freshworks creates AI-boosted business software that helps employees work more efficiently and effectively. Managing data across multiple RDBMS and NoSQL databases was already a challenge at their current scale. To prepare for 10X growth, they knew it was time to rethink their database strategy. Learn how they architected a solution that would simplify scaling while keeping costs under control.
Skybuffer AI: Advanced Conversational and Generative AI Solution on SAP Busin...Tatiana Kojar
Skybuffer AI, built on the robust SAP Business Technology Platform (SAP BTP), is the latest and most advanced version of our AI development, reaffirming our commitment to delivering top-tier AI solutions. Skybuffer AI harnesses all the innovative capabilities of the SAP BTP in the AI domain, from Conversational AI to cutting-edge Generative AI and Retrieval-Augmented Generation (RAG). It also helps SAP customers safeguard their investments into SAP Conversational AI and ensure a seamless, one-click transition to SAP Business AI.
With Skybuffer AI, various AI models can be integrated into a single communication channel such as Microsoft Teams. This integration empowers business users with insights drawn from SAP backend systems, enterprise documents, and the expansive knowledge of Generative AI. And the best part of it is that it is all managed through our intuitive no-code Action Server interface, requiring no extensive coding knowledge and making the advanced AI accessible to more users.
Digital Marketing Trends in 2024 | Guide for Staying AheadWask
https://www.wask.co/ebooks/digital-marketing-trends-in-2024
Feeling lost in the digital marketing whirlwind of 2024? Technology is changing, consumer habits are evolving, and staying ahead of the curve feels like a never-ending pursuit. This e-book is your compass. Dive into actionable insights to handle the complexities of modern marketing. From hyper-personalization to the power of user-generated content, learn how to build long-term relationships with your audience and unlock the secrets to success in the ever-shifting digital landscape.
FREE A4 Cyber Security Awareness Posters-Social Engineering part 3Data Hops
Free A4 downloadable and printable Cyber Security, Social Engineering Safety and security Training Posters . Promote security awareness in the home or workplace. Lock them Out From training providers datahops.com
TrustArc Webinar - 2024 Global Privacy SurveyTrustArc
How does your privacy program stack up against your peers? What challenges are privacy teams tackling and prioritizing in 2024?
In the fifth annual Global Privacy Benchmarks Survey, we asked over 1,800 global privacy professionals and business executives to share their perspectives on the current state of privacy inside and outside of their organizations. This year’s report focused on emerging areas of importance for privacy and compliance professionals, including considerations and implications of Artificial Intelligence (AI) technologies, building brand trust, and different approaches for achieving higher privacy competence scores.
See how organizational priorities and strategic approaches to data security and privacy are evolving around the globe.
This webinar will review:
- The top 10 privacy insights from the fifth annual Global Privacy Benchmarks Survey
- The top challenges for privacy leaders, practitioners, and organizations in 2024
- Key themes to consider in developing and maintaining your privacy program
leewayhertz.com-AI in predictive maintenance Use cases technologies benefits ...alexjohnson7307
Predictive maintenance is a proactive approach that anticipates equipment failures before they happen. At the forefront of this innovative strategy is Artificial Intelligence (AI), which brings unprecedented precision and efficiency. AI in predictive maintenance is transforming industries by reducing downtime, minimizing costs, and enhancing productivity.
zkStudyClub - LatticeFold: A Lattice-based Folding Scheme and its Application...Alex Pruden
Folding is a recent technique for building efficient recursive SNARKs. Several elegant folding protocols have been proposed, such as Nova, Supernova, Hypernova, Protostar, and others. However, all of them rely on an additively homomorphic commitment scheme based on discrete log, and are therefore not post-quantum secure. In this work we present LatticeFold, the first lattice-based folding protocol based on the Module SIS problem. This folding protocol naturally leads to an efficient recursive lattice-based SNARK and an efficient PCD scheme. LatticeFold supports folding low-degree relations, such as R1CS, as well as high-degree relations, such as CCS. The key challenge is to construct a secure folding protocol that works with the Ajtai commitment scheme. The difficulty, is ensuring that extracted witnesses are low norm through many rounds of folding. We present a novel technique using the sumcheck protocol to ensure that extracted witnesses are always low norm no matter how many rounds of folding are used. Our evaluation of the final proof system suggests that it is as performant as Hypernova, while providing post-quantum security.
Paper Link: https://eprint.iacr.org/2024/257
5th LF Energy Power Grid Model Meet-up SlidesDanBrown980551
5th Power Grid Model Meet-up
It is with great pleasure that we extend to you an invitation to the 5th Power Grid Model Meet-up, scheduled for 6th June 2024. This event will adopt a hybrid format, allowing participants to join us either through an online Mircosoft Teams session or in person at TU/e located at Den Dolech 2, Eindhoven, Netherlands. The meet-up will be hosted by Eindhoven University of Technology (TU/e), a research university specializing in engineering science & technology.
Power Grid Model
The global energy transition is placing new and unprecedented demands on Distribution System Operators (DSOs). Alongside upgrades to grid capacity, processes such as digitization, capacity optimization, and congestion management are becoming vital for delivering reliable services.
Power Grid Model is an open source project from Linux Foundation Energy and provides a calculation engine that is increasingly essential for DSOs. It offers a standards-based foundation enabling real-time power systems analysis, simulations of electrical power grids, and sophisticated what-if analysis. In addition, it enables in-depth studies and analysis of the electrical power grid’s behavior and performance. This comprehensive model incorporates essential factors such as power generation capacity, electrical losses, voltage levels, power flows, and system stability.
Power Grid Model is currently being applied in a wide variety of use cases, including grid planning, expansion, reliability, and congestion studies. It can also help in analyzing the impact of renewable energy integration, assessing the effects of disturbances or faults, and developing strategies for grid control and optimization.
What to expect
For the upcoming meetup we are organizing, we have an exciting lineup of activities planned:
-Insightful presentations covering two practical applications of the Power Grid Model.
-An update on the latest advancements in Power Grid -Model technology during the first and second quarters of 2024.
-An interactive brainstorming session to discuss and propose new feature requests.
-An opportunity to connect with fellow Power Grid Model enthusiasts and users.
Mass transfer coefficient evaluation for lab scale fermenter using sodium sulphite oxidation method
1. Chemical and Process Engineering Research www.iiste.org
ISSN 2224-7467 (Paper) ISSN 2225-0913 (Online)
Vol 2, 2012
Mass transfer coefficient evaluation for lab scale fermenter
using sodium sulphite oxidation method
Rajesh G.1, Roshan M.1 and Shridhar S.B.*2
1
Department of Biotechnology, PESIT, Bangalore, Karnataka, India, ghosh.rajesh@yahoo.co.in
2
Department of Chemical Engineering, Rural Engineering College, Hulkoti, Gadag, Karnataka, India,
shridhar_bagali@yahoo.com
Abstract - Oxygen transfer is often the rate-limiting step in the aerobic bioprocess due to the low solubility
of oxygen inside the aqueous solution. The rate of reaction is such that as oxygen enters the liquid phase, it
is immediately consumed to oxidize the sulfite so that the rate of oxidation is equivalent to the oxygen-
transfer rate. Reaction rate often determined by titration is much faster than oxygen transfer rate so that
gas- liquid mass transfer is the rate controlling step. The current study involves using central composite
design, a statistical technique to find out the parameter conditions for the optimum volumetric mass transfer
coefficient in a lab scale (2L) fermentor. The optimum volumetric mass transfer coefficient was found to
lie outside the range of parameters studied and analytical expressions was obtained to predict the
volumetric mass transfer coefficients for the parameter ranges studied using response surface methodology.
The analytical expression was found to be significantly valid based on ANOVA results.
Keywords: Aerobic bioprocess; Sodium sulphite oxidation process; Mass transfer coefficient; Central
composite design
INTRODUCTION
In aerobic fermentation processes, oxygen is an important nutrient/substrate for the growth, maintenance and
production of metabolites. However, oxygen is sparingly soluble in aqueous and/or fermentation media due to its
low solubility. Hence, oxygen needs to be supplied continuously during the fermentation. Oxygen transfer rate into
the fermentation media and oxygen uptake rate by microorganisms govern the design and scale-up of fermenters [1].
Since one has little control on the oxygen uptake rate governed by microorganisms, it is necessary to enhance the
rate of transfer of oxygen into the fermentation medium. The transfer of oxygen into the liquid is usually
accomplished by sparging air or oxygen into the medium. Gas-liquid film theory, it can be stated that the oxygen
mass transfer rate is limited by the resistance of the liquid film surrounding the gas bubbles which in turn limits the
volumetric mass transfer coefficient. Volumetric mass transfer coefficient is the product of liquid mass transfer
coefficient and the interfacial area. Interfacial area is difficult to measure and is usually lumped with the liquid mass
transfer coefficient to get the volumetric mass transfer coefficient. To explain the mass transfer of gases into liquid,
several theories such as Whitman’s two-film theory according to this theory equilibrium is assumed based on rigid
interface and the resistances to mass transfer in the two phases are added to get an overall resistance, Higbie’s
penetration theory-there is a continual attachment and deattachment of small liquid eddies at the gas-liquid
interface, in the interval of attachment there is a interchange of solute by molecular diffusion, eddies from a
turbulent bulk fluid, come to within a random distances of the surface, gives slightly higher exponents for the
diffusivity, which indicates this theory might apply for mass transfer to flat surfaces such as pool of liquid, Higbie’s
was the first to apply this equation to gas absorption in a liquid , showing diffusing molecule will not reach the other
side of a thin layer if the contact time is short Kc = 1.13 √(D /t). Danckwert’s surface renewal theory here elements
of fluid at the transfer surface are randomly replaced by fresh liquid from bulk stream the surface renewal rate is
considerably higher than that found for bubbles in free rise under potential flow An exponential distribution of ages
or contact times , the average transfer coefficient is given by Kc = √(D × s). Where D is diffusivity of gas in a liquid
is fractional renewal rate [1-3]. In (1951) a combination of these theories has been proposed for prediction of mass
transfer coefficient. However, parameters such as film thickness for Whitman’s two film theory, exposure time for
10
2. Chemical and Process Engineering Research www.iiste.org
ISSN 2224-7467 (Paper) ISSN 2225-0913 (Online)
Vol 2, 2012
Higbie’s penetration theory and surface renewal rate for Danckwert’s surface renewal theory cannot be measured
experimentally and has to be calculated if mass transfer coefficient value is known [4]. This technique is interesting
for studying the influence of operational conditions on the volumetric mass transfer coefficient, and is widely
employed in the literature. Nevertheless, it is necessary to take into account that the response time of the electrode,
τr, is a critical parameter for the determination of accuracy values of oxygen concentration. This response can affect
the correct determination of the mass transfer coefficient if the time characteristic for the oxygen transport, 1/kLa,
is of the same order than the response time of the electrode, defined as the time necessary to reach 63% of the final
value of measured when exposed to a step change concentration The response time of the electrode can be
determined by transferring the oxygen electrode from a solution with sodium sulfite (whose oxygen concentration is
zero) to another dissolution saturated with air (100% of saturation). In the case when the electrode of oxygen has
a high value of response time it would be necessary to introduce a correction in the response model are available to
experimentally determine the volumetric mass transfer coefficient. The most widely used is the sulphite oxidation
method. The sulphite oxidation method tends to give higher values for the volumetric mass transfer coefficient and
the order of the reaction depends on the concentrations of the sulphite and catalyst. (Usually a divalent cation of
Cu++ or Co++). In order to obtain an adequate reaction rate, avoiding acceleration of oxygen uptake due to the
chemical reaction.
The aim of this study is to predict volumetric mass transfer coefficient based on parameters both physical
and chemical viz., impeller speed and air flow rate. For sodium sulphite oxidation method, Central composite design
was used to optimize the volumetric mass transfer coefficient for both impeller speed and air flow rate. The rate of
dissolution of gas inside the liquid solution is studied by knowing the reaction kinetics and mass transfer theories.
MATERIAL AND METHODS
Sodium Sulphite Oxidation Method
Sodium sulphite oxidation method was first developed [5]. This method is based on the reaction of sodium
sulfite, a reducing agent, with the dissolved oxygen to produce sulfate, in the presence of a catalyst (usually a
divalent cation of Cu++ or Co++). 0.003 M of copper sulphate solution was prepared in 1 L of de-mineralized water
which was then transferred to the fermentor vessel. Agitation was started immediately at the required rpm. To this
was added 1 L of 0.05 M sodium sulphite . Molecular weight of copper sulphate =126. Weight of copper sulphate =
6.3 gm. simultaneously, air was pumped into the solution via a sparger continuously. The oxygen in the air was
immediately consumed by the sulphite oxidation [1,2] Since the reaction rate is much faster than the oxygen transfer
rate, so the limiting factor is the oxygen transfer rate [6]. When the dissolved oxygen concentration reached 0%
saturation, the remaining unreacted sodium sulphite reacted with oxygen until no more sodium sulphite was present
in the solution. Air was pumped continuously till the oxygen concentration in the fermentor reached 100%
saturation. At regular intervals of time, a sample was withdrawn from the fermentor. The sample was mixed with an
excess of iodine reagent. weight accurately 2 gm, sodium sulphite of concentration 0.05(M), add excess iodine
solution which reacts with unconsumed sulphite. The amount of residual sulfite can be also estimated indirectly by
the stoichiometry of the reaction on basis of colorimetric determination of the iodine concentration. The sample was
then titrated with standard sodium thiosulphate solution (Na2S2O3.5H2O) 0.1(N) Finally titrating with standard
sodium thiosulfate solution (Na2S2O3) to a starch indicator end point to a starch indicator end point. The rate of
sodium sulfite consumption was determined determine from titration of sodium sulphite against sodium thiosulphate
and kLa calculated according to the following equation. (( - d C Na2SO3) / dt ) = 2 KLaC*. The order of the reaction for
both i.e., oxygen consumption and sodium sulphite consumption are determined by plotting ln (C/Co) versus time
for oxygen consumption and concentration of sodium sulphite versus time for sulphite consumption to obtain linear
plots [1].
Experimental design and data analysis: Central composite design (CCD)
11
3. Chemical and Process Engineering Research www.iiste.org
ISSN 2224-7467 (Paper) ISSN 2225-0913 (Online)
Vol 2, 2012
In order to study the combined effect of design or mechanical parameters such as impeller speed, and
process or chemical parameters such as air flow rate , a statistical approach namely response surface methodology
has been used. The process conditions can be optimized using Response surface methodology. Response surface
methodology is an empirical modelization technique devoted to the evaluation of the relationship of a set of
controlled experimental factors and observed results. Basically this optimization process involves three major steps,
performing the statistically designed experiments, estimating the coefficients in a mathematical model, and
predicting the response and checking the adequacy of the model. The Central composite design is employed for the
optimization of process conditions [7]. According to the Central composite design, the total number of treatment
combinations was 2k + 2k + no where ‘k’ is the number of independent variables and no is the number of repetition of
experiments at the center point. The total number of design points is thus N = 2k + 2k + no. The significant variables
like speed of impeller & air flow rate were chosen as the critical variables and designated as X1 and X2 respectively.
The low, middle, and high levels of each variable were designated as −, 0, and + respectively. -α and +α are the
extreme levels in the range studied for each variable ,α describe a circular design geometry ,which reduce errors by
locating the axial points at the lower and upper bound of the variable ranges, which gives direct , mutual,
curvilinear interaction . Factorial point should range -1 and +1, axial point –1.414 and +1.414 are intermediate
levels between the central and extreme levels of each variable, and 0 is the central level in the range studied for each
variable. The experimental range for Speed of impeller & Air flow rate are chosen for this study (Obtained using
Design Expert Software, Stat-Ease, U.S.A.) is given in Table 1.
A 22-factorial central-composite-experimental-design was employed and all in duplicate, leading to 13 sets of
experiments, was used to optimize the mass transfer coefficient. Experimental plan employed for the optimization of
impeller speed and air flow rate. For statistical calculation, the variable Xi have been coded as xi according to the
following transformation: xi = (Xi –Xo)/δX, Where xi is the dimensionless coded value of the independent variable
Xi, Xo is the actual value of the independent variable Xi at the center point and X is the step change. The optimum
mass transfer coefficient is taken as the dependent variable or response Ŷ. Regression analysis was performed on the
data obtained. The behavior of the system was explained by the following second order polynomial equation. Y = βo
+ Σβi xi + Σβii xi2 + Σβij xi xj, where, Y = predicted response, βo = offset term, βi = linear effect, βii = squared
effect, and βij = interaction effect. xi and xj = coded value of independent variables. The regression equation was
optimized for maximum value to obtain the optimum conditions using MATLAB version 7.0 The second order
polynomial equation was obtained using Design-Expert software [8].
Results and Discussions
The volumetric mass transfer coefficient was determined using sodium sulphite oxidation method. The experiments
were carried out in 2 L (working volume) fermenter. The conventional practice of single factor optimization by
keeping other involving factors at unspecified constant levels does not depict the combined effect of all the factors
involved. Also this method requires carrying out a number of experiments to determine the optimum levels, which
will not give true values. Optimizing all the affecting parameters combined by statistical experimental design can
eliminate these drawbacks of single factor optimization process. The effect of the process conditions namely
impeller speed and air flow rate were studied using a second order central composite experimental design (CCD)
[7]. A total of 13 experiments with different combinations of impeller speed and air flow rate were performed using
central composite design to find the parameter conditions where the optimum volumetric mass transfer coefficient
occurs. Table 2 show the comparison between experimental and predicted values for the volumetric mass transfer
coefficient using sodium sulphite oxidation method. The error was well within + 10 % indicating that the empirical
expression for the prediction of volumetric coefficient is valid. The expression obtained in terms of coded factors is
given by the equation, Y1 = 607.58 - 23.99x1 - 36.60x2 - 15.08x1x2 + 27.66x12 + 14.59x22 , where Y1 is the response
variable i.e., volumetric mass transfer coefficient, x1 and x2 are coded values of independent variables, i.e.,
impeller speed and air flow rate respectively . Actual form of the empirical expression gives the predicted value of
12
4. Chemical and Process Engineering Research www.iiste.org
ISSN 2224-7467 (Paper) ISSN 2225-0913 (Online)
Vol 2, 2012
volumetric mass transfer coefficient. Y2 = 749.257 - 0.5878X1 - 4.3599X2 - 0.02512X1X2 + 0.0006 X12 + 1.618 X22.
WhereY2 is the response variable, Volumetric mass transfer coefficient. X1 and X2 actual values of independent
variables, i.e., impeller speed and air flow rate respectively.
The independent and the dependent variables were fitted to the second-order model equation. They were examined
in terms of the goodness of fit. The goodness of fit of the regression equation Y 1 was evaluated by the coefficient of
determination (R2) and the coefficient of relation (R). The coefficient of determination (R 2) is a measure of total
variation of observed values of extracted oil about the mean explained by the fitted model. The coefficient of
correlation (R) explains the correlation between the experimental and predicted values from the model. A good
model equation explains most of the variations in the response. The coefficient of determination (R 2) is 0.9204. This
value indicates that the response model can explain 92.04% of the total variability in the responses. The coefficient
of correlation (R) is 0.9593.The closer value of coefficient of correlation (R) to unity is the better. Statistical testing
of the model was done in the form of variance (ANOVA), which is required to test the significance and adequacy of
the model. The reliability of the suggested model was tested using the Fisher’s statistical test (F). The results of
statistical testing using ANOVAs are given in Table 3.
Values of " Probability (P) > F"less than 0.05 indicate that the model terms are significant. The ANOVA of the
regression model corresponding to quadratic for volumetric mass transfer coefficient Table 3 demonstrates that the
model is highly significant, as it is evident from the calculated F-value (= 28.74) and a very low probability value
(Probability(P) > F = 0.0009). Moreover the computed F-value (F= 28.74) is much greater than the F value (F0.005 (5,
7) = 9.52) obtained from the standard distribution table, so the null hypothesis is rejected at 5% α level of
significance [7-8]. From Figure 1 it can be observed that a stationary point exists although it is outside the range
based on the shape of the contour plot. The response surface plot shown in Figure 2 for the chosen model Y 1
illustrates the three dimensional relationship for the effects of impeller speed and air flow rate on volumetric mass
transfer coefficient. The response surface indicates that the volumetric mass transfer coefficient increases with
decrease in impeller speed and subsequent increase in air flow rate. This result indicates that two variables had
mutually dependent influence on the volumetric mass transfer coefficient.
CONCLUSION
Evaluation of mass transfer coefficients in fermenters were studied using central composite design to get the
optimum value. A total of 13 experiments for each set were employed to determine the volumetric mass transfer
coefficients. The order of the reaction for oxygen consumption for 2 L sodium sulphite oxidation method was found
to be first order and zero order for the case of sodium sulphite oxidation. Optimum volumetric mass transfer
coefficient was found from response surface methodology to be outside the range of parameters studied. Analytical
expressions for predicting the volumetric mass transfer coefficient for the range of impeller speed and air flow rate
tested were obtained using response surface methodology.
Nomenclature
kLa = Volumetric mass transfer coefficient, C* = Equilibrium concentration in moles /liter, t = Time in minutes or
sec and CNa2S03 = Concentration of sodium sulphite in mol/liter
ACKNOWLEDGEMENTS
The authors thank to General Manager Dr T N Shasidhara (Mechanical and Design), Sartorius, Bangalore for
encouragement. Authors thank Dr. Y J Rao , Visiting Professor of S.I.T, Tumkur and Principal of Basava College of
Engineering , Bangalore for valuable suggestions. The author Rajesh Ghosh expresses his heartfelt gratitude and
sincere thanks to Dr P. Nirguna Babu, SIT, Tumkur, for providing an opportunity to work at Sartorius Biotech India
Private Limited for M. Tech. project work.
13
5. Chemical and Process Engineering Research www.iiste.org
ISSN 2224-7467 (Paper) ISSN 2225-0913 (Online)
Vol 2, 2012
REFERENCES
[1] Felix G.O., Emillio G. (2009) Biotechnology Advances., 27, 153-176.
[2] Warren L.M., Smith J., Peter H. (2001) Mc Graw Hill Publication, Chemical Engineering Series., 6, 524-
529.
[3] Danckwerts P.V., (1951) Ind. Eng. Chem, 43, 1460–1467.
[4] Garcia O.F., Gomez E., (2004) Chem Eng Sci, 59, 489–501.
[5] Cooper C. M., Fernstrom G.A., Miller S.A., (1994) Ind. Eng. Chem, 36, 504-509.
[6] Nienow A.W., Lilly M.D., (1979) Biotechnology and Bio chemical engineering journal, 21, 2341-2345.
[7] Khuri A.I., Cornell J.A., (1987) Text
books and monographs, New York, Marcel Dekkar.
[8] Douglas C.M., (1997) 4th edition, John Wiley and Sons, New York.
Table 1. Experimental range and levels of impeller speed and air flow rate in Central composite design (CCD).
Parameter Level
-α -1 0 +1 +α
Speed of impeller 217.16 300 500 700 782.84
Air flow rate 4.76 6 9 12 13.24
Table 2. Comparison of experimental and predicted values of volumetric mass transfer coefficient for 2 L sodium
sulphite oxidation method
Run Impeller Air flow Volumetric mass transfer (%)-Error
speed (rpm) rate (lpm) coefficient kLa (hr-1)
Experimental Model
1 500.00 9.00 611.985 608.583 0.555
2 782.84 9.00 609.151 675.977 1.177
14
6. Chemical and Process Engineering Research www.iiste.org
ISSN 2224-7467 (Paper) ISSN 2225-0913 (Online)
Vol 2, 2012
3 217.16 9.00 710.677 675.977 0.588
4 500.00 9.00 609.151 608.583 0.093
5 500.00 9.00 607.735 608.583 -0.139
6 500.00 9.00 604.151 608.583 0.608
7 300.00 12.00 727.204 721.619 -0.768
8 500.00 13.24 670.539 678.583 -1.257
9 700.00 12.00 672.900 670.774 0.315
10 500.00 4.76 596.402 575.691 3.472
11 700.00 6.00 609.151 626.961 -2.923
12 500.00 9.00 604.902 608.583 0.093
13 300.00 6.00 603.151 608.583 -2.497
Table 3. Analysis of Variance (ANOVA) Table for the effect of
speed of impeller, air flow rate on volumetric mass transfer coefficient.
Source Sum of Degrees of Mean F value *Probability(P)>F
squares freedom square
Model 24505.94 5 4901.19 28.74 0.0009
Error 1193.78 7 170.54 significant
15
7. Chemical and Process Engineering Research www.iiste.org
ISSN 2224-7467 (Paper) ISSN 2225-0913 (Online)
Vol 2, 2012
Figure 1. Isoresponse contour plots showing the effect of impeller speed and air flow rate and their interactive effect
on the volumetric mass transfer coefficient for 2 L sodium sulphite oxidation method.
Figure 2. Response surface plot showing the effect of impeller speed and air flow rate and their interactive effect on
the volumetric mass transfer coefficient for 2 L sodium sulphite oxidation method
16
8. This academic article was published by The International Institute for Science,
Technology and Education (IISTE). The IISTE is a pioneer in the Open Access
Publishing service based in the U.S. and Europe. The aim of the institute is
Accelerating Global Knowledge Sharing.
More information about the publisher can be found in the IISTE’s homepage:
http://www.iiste.org
The IISTE is currently hosting more than 30 peer-reviewed academic journals and
collaborating with academic institutions around the world. Prospective authors of
IISTE journals can find the submission instruction on the following page:
http://www.iiste.org/Journals/
The IISTE editorial team promises to the review and publish all the qualified
submissions in a fast manner. All the journals articles are available online to the
readers all over the world without financial, legal, or technical barriers other than
those inseparable from gaining access to the internet itself. Printed version of the
journals is also available upon request of readers and authors.
IISTE Knowledge Sharing Partners
EBSCO, Index Copernicus, Ulrich's Periodicals Directory, JournalTOCS, PKP Open
Archives Harvester, Bielefeld Academic Search Engine, Elektronische
Zeitschriftenbibliothek EZB, Open J-Gate, OCLC WorldCat, Universe Digtial
Library , NewJour, Google Scholar