Phase Equilibrium Studies on N-Oxidation Systems to Determine Homogeneous Mixture Conditions

The N-oxidation of alkylpyridines is used in the pharmaceutical industries to synthesize alkylpyridine N-oxides that are involved in the production of analgesic and anti-inflammatory drugs. The synthesis process involves continuous addition of aqueous hydrogen peroxide (35% w/w) solution to a mixture of alkylpyridine and phosphotungstic acid catalyst. The oxidation is accompanied by undesired decomposition of hydrogen peroxide, which produces large amounts of oxygen and water vapor. This reaction introduces a series of hazards during the operation including the potential to over pressurize an improperly vented reactor and generation of an oxygen-rich atmosphere in an alkyl pyridine flammable environment. The decomposition is accelerated during the N-oxidation of higher order alkylpyridines (lutidines, collidines) due to mass transfer limitations caused by the separation of the liquid into organic and aqueous phase. Also, the presence of phosphotungstic acid (catalyst) in the aqueous phase further intensifies the peroxide decomposition reducing the safety and efficiency of the process. It is thus essential to identify homogeneous reaction conditions and operate the reactor in a regime where phase separation is prevented. The immiscibility between the alkylpyridine and water is primarily responsible for the liquid phase heterogeneity during the N-oxidation. The current work addresses this research gap by investigating the influence of the alkylpyridine N-oxide on the phase separation since the N-oxide is known for its increased reactivity. Experimental and theoretical studies were conducted on 2,6-lutidine/2,6-lutidineN-oxide/water mixtures at different temperatures. The phase equilibrium experiments were conducted at 110 °C in lab-scale calorimeters wherein the ternary mixtures were analyzed with the help of in-situ FTIR spectroscopy. It was found that the extent of heterogeneity between 2,6-lutidine and water is reduced dramatically by the presence of 2,6-lutidine-N-oxide as indicated by the phase diagram. In order to support the experimental work, the UNIQUAC thermodynamic model was used to estimate the biphasic compositions and predict the LLE curve for the ternary mixture. The energy parameters used in the equations, which describe the intermolecular interactions were calculated based on molecular dynamics simulations. Apart from this, the molecular parameters for N-oxide were obtained by following a quantum mechanical approach, which utilized a surface building algorithm for constructing the molecular surface. The results predicted by the model provide a satisfactory representation of the experimental data at T = 110 °C. In addition to this, the influence of temperature on the phase behavior was studied by generating phase equilibrium data at T = 100 and 125 °C. The findings from this research study can be used to implement the inherent safety concept – “Hybridization” to the N-oxidation system wherein the concentration of product N-oxide can be controlled to maintain a less hazardous environment

Images of Loss in Tennessee Williams\u27s The Glass Menagerie, Arthur Miller\u27s Death of a Salesman, Marsha Norman\u27s night, Mother, and Paula Vogel\u27s How I Learned to Drive

This dissertation offers an analysis of the image of loss in modern American drama at three levels: the loss of physical space, loss of psychological space, and loss of moral space. The playwrights and plays examined are Tennessee Williams\u27s The Glass Menagerie (1945), Arthur Miller\u27s Death of a Salesman (1949), Marsha Norman\u27s \u27night, Mother (1983), and Paula Vogel\u27s How I Learned to Drive (1998). This study is the first scholarly work to discuss the theme of loss with these specific playwrights and works. This dissertation argues that loss is a central trope in twentieth-century American drama. The purpose of this dissertation is to analyze how the image of loss is modified and transformed in each playwright\u27s work leading these images to reveal an emotional truth that transcends the plight of particular individuals or families and casting a universal appeal to a diverse audience. Chapters examine specific themes related to the theme of loss. As part of the critical methodology, the live spectacle of performance has been acknowledged. This study analyzes how Williams, Miller, Norman, and Vogel modify and transform the image of loss by focusing on the myth of the American dream, illusion versus reality, empowerment, and the complexity of human relationships. Although these plays are meant first and foremost to be appreciated as theater, that is to say live performance, this study deals with these plays as drama, that is, as written texts. The audience observing the live spectacle and the reader of the text are both challenged to define their own space. Williams, Miller, Norman, and Vogel, modify and transform the image of loss to reveal a common humanity that is not only a force in their work, but also a strong presence in the works of American dramatists as diverse as Eugene O\u27Neill and Adrienne Kennedy. From domestic drama to the drama of social and political criticism, Williams, Miller, Norman, and Vogel along with a medley of American playwrights, have taken the genre of American drama from backseat status (secondary to the novel and poem) into the forefront of recognized American literature

Structural Fill of Steel Slag Caused Heave of a Building

The results of an investigation on the cause of damage to a two-story industrial building supported on 5.5m of steel slag fill in the town of Monclova in the north of Mexico are presented. Since six years it was built, the floor slab heaved between 2om and 25om. The columns were raised up between 2 cm and 20 cm. These movements cracked the building. Chemical analysis of slag showed 22% of calcium oxide and 5% of magnesium oxide, which on hydration cause swelling. At a distance of 4m on one side of the building was a hearth-bath, a molten iron pit, 5mx5m & 4m deep c0nstructedin the same slag fill. The heat transmitted from the hearth-bath to the fill beneath the building caused it to swell. The swell was proportional to the heat transmitted. The maximum heave was 25 cm at a distance of 4 m from the heat source. The heave decreased at increasing distances from the heat source

Simulation of Convective Heat Transfer in 3D Forward Facing Step Using Various Turbulence Models

In this work, a modified solver from the OpenFOAM 4.1 software was used to study the fluid flow and heat transfer characteristics over a forward facing step (FFS) considering various turbulence models, viz., k-ε, k-ω, k-ω SST and v2-f. Numerical computations were performed using a newly developed transient solver, pisoTempFoam. Modeling and meshing of the geometry and setting of the boundary conditions were done with OpenFOAM. The bottom (upstream, step and downstream) walls were heated at a constant temperature of 350K, while the fluid inlet temperature was 298K. The simulation results were compared with those available in the literature. Variation of skin friction coefficient (Cf), coefficient of pressure (Cp), and Nusselt number (Nu) for different Reynolds numbers (Re), contraction ratios (CR) and different fluids are presented. This article also presents information about recirculation bubbles in the upstream and downstream regions of the FFS. The results show that the combined effect of turbulence models and parameters, such as CR, Re and Pr, change the flow and heat transfer characteristics of the FFS. The present CFD simulation plays a pivotal role in the analysis of flow over airfoils at a large angle of attack in heat exchangers and pipes whose area suddenly changes

Permeability of Clays under Organic Permeants

A Magnesium Montmorillonite and a Kaolinite Clay Are Subjected to Organic and Inorganic Permeants to Study the Changes in Permeability Caused by the Reaction between Clays and Permeants. the Permeants Are Acetic Acid, Aniline, Methanol, and Xylene. Tests Are Conducted in Specially Designed and Constructed Flexible Wall Permeameters that Provide Precise Measurements of Pressures and Flows. Increases in Clay Permeability Due to Clay-Permeant Chemical Reactions Are Measured to Be on the Order of Two to Three Times the Original Permeability. This is in Contrast to the 100 to 1,000 Times Increases Reported by Others. the Writers Believe that the Large Increases Reported by Others is Probably Due to the Use of Fixed-Wall Permeameters. the Writers\u27 Results Show that Methanol Doubles the Permeability of Montmorillonite. Acetic Acid Reacts with the Carbonates in Montmorillonite and Liberated Carbon Dioxide. the Resulting Loss of Mass Triples the Clay\u27s Permeability. Aniline and Xylene Will Not Flow through Saturated Montmorillonite but Will Flow through Saturated Kaolinite at Reduced Flow Rates. Hydraulic Fracturing of the Montmorillonite Occurred When Methanol Passed through It under a High Gradient and Low Confining Pressure. © ASCE

Part Repair using a Hybrid Manufacturing System

Nowadays, part repair technology is gaining more interest from military and industries due to the benefit of cost reducing as well as time and energy saving. Traditionally, part repair is done in the repair department using welding process. The limitations of the traditional welding process are becoming more and more noticeable when the accuracy and reliability are required. Part repair process has been developed utilizing a hybrid manufacturing system, in which the laser aided deposition and CNC cutting processes are integrated. Part repair software is developed in order to facilitate the users. The system and the software elevate the repair process to the next level, in which the accuracy, reliability, and efficiency can be achieved. The concept of repair process is presented in this paper. Verification and experimental results are also discussed.Mechanical Engineerin

Removal of chlorobenzene and 1,4-dichlorobenzene using novel poly-o-toluidine zirconium(IV) phosphotellurite exchanger

Novel hybrid exchanger poly-o-toluidine zirconium(IV) phosphotellurite was synthesized and physicochemical properties of the material were well studied by FTIR, XRD, TGA, SEM-EDX and TEM analysis. The composite exchanger showed good ion exchange capacity and excellent removal potential towards US Environmental Protection Agency listed priority pollutants like chlorobenzene and 1,4-dichlorobenzene. The factors affecting the adsorption like time, pH and temperature were studied in detail using UV spectrophotometry. More than 90% of the pollutants were successfully removed using the exchanger. The composite also showed selectivity towards heavy metal ions, especially mercury ions. The sorption kinetics of the material was studied in detail using pseudo first order and pseudo second order kinetics. The material followed pseudo second order kinetic model indicating chemisorption of the pollutants. The composite can be successfully used for environmental remediation purposes

MAPPING NETWORK DEPLOYMENTS TO BEST PRACTICES DESIGN RECOMMENDATION

Presented herein are techniques for computing a profile alignment score that indicates how closely a customer’s network deployment is adhering to a company’s best practices design and validation guides. The profile alignment score is calculated based on telemetry information associated with the customer. According to techniques described herein, customers are provided a report that includes the profile alignment score and outlines areas in which the customer’s deployment may be improved

Pectin-Tin(IV) molybdosilicate: An ecofriendly cationic exchanger and its potential for sorption of heavy metals from aqueous solutions

A novel composite cation exchanger of biopolymer Pectin and Tin(IV) molybdosilicate heteropoly acid salt were prepared by co-precipitation technique. Physico-chemical characterization of Pectin-Tin(IV) molybdosilicate was performed using instrumental techniques such as FTIR, TG, XRD and SEM-EDS. Studies were carried out to investigate ion exchange capacity. pH titration carried out shows cationic nature and polyfunctionality of the exchanger. Distribution coefficients of various metal ions were done to explore the ion exchange behavior of cation exchanger. Distribution studies show that the material is highly selective for toxic heavy metal ions such as Cd2+ , Cu2+ , Al3+ etc. To investigate the environmental applicability of the exchanger some analytically important binary separations and selective separation of metal ions from industrial effluents were achieved. Kinetic and isotherm parameters were evaluated to predict the mechanism of sorption of heavy metal ions. Mass transfer analysis shows that internal particle diffusion and some degree of boundary layer control the sorption process