Chemical Engineering Commons^™

Influence Of Morphology And Processing On Xps Characterisation Of Sro-Ca-Zno-Sio2 Glass, F. R. Laffir, A. W. Wren, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

A study was conducted to demonstrate the influence of morphology and processing on X-ray photoelectron spectroscopic (XPS) characterization SrO-Ca-ZnO-SiO₂ glass. The glass formulation being investigated was originally synthesized for developing a novel glass polyalkenoate cement (GPC). High resolution photoelectron spectra of Zn 2p, Ca 2p, Sr 3d, Si 2p, O 1s, and C 1s were recorded for the different forms of glass. It was observed that there was preferential enrichment of Zn²⁺ with an increase in the proportion of NBO for the investigated BT101 glass. The relative atomic concentration of Zn in BT101 glass was high and resulted …

Design Of Drug Delivery Strategies Based On Well-Stirred Experiments, Kumud Kanneganti

Theses

Drugs are generally administered to the human body via injections (IV) or through other paths such as the buccal, nasal routes. The main consideration when designing a medication schedule is to maintain a therapeutic level of the drug in the body during the course of treatment. To achieve this goal, when IV drug therapy is selected, particular importance has to given to the dose to be injected and how to maintain the concentration of the pharmaceutical active ingredient (API) in the body between a Minimum Toxic Concentration (MTC) and a Minimum Effective Concentration (MEC). This therapeutic range varies with the …

Minimum Agitation Speed For Solid Suspension And Mixing Time In A Torispherical -Bottomed Pharmaceutical Stirred Tank Under Different Baffling Conditions, Dilanji Bhagya Wijayasekara

Theses

The minimum agitation speed, NS, required to just suspend solid particles dispersed in water was experimentally determined in this work for a glass-lined type of mixing tank provided with a torispherical bottom and agitated with a retreat-blade impeller under different baffling configurations. Ns for the same tank but equipped with a different agitation system, namely an axial impeller, was also experimentally determined for the purpose of comparing of performances of the two systems. The effect of impeller off- bottom clearance and the vessel's liquid level on the minimum agitation speed were also experimentally studied. Njs, was experimentally determined …

Effects Of Monoclonal Anti-Abeta Antibodies On The Amyloid Beta Peptide Fibrillogenesis And Their Involvement In The Clearance Of Alzheimer's Disease Plaques, Jeffy Pilar Jimenez

USF Tampa Graduate Theses and Dissertations

Alzheimer’s disease (AD) is the most common cause of senile dementia worldwide. AD is a neurodegenerative disorder characterized by the loss of memory and language skill, collapse of the cognitive function, and distortion of social behavior. As of today, the onset mechanisms of AD and cure are unknown; however, three hallmarks are commonly encountered: extra and intracellular accumulation of amyloid beta (A!) peptide plaques, formation of intracellular neurofibrillary tangles, and inevitable neuronal death. Hypothetically, a possible scenario provoking or involved in the onset of AD is a cascade effect that starts with an imbalance in the production and clearance of …

Electrocatalytic Oxidation Of Hcooh At Au(Core)-Pd(Shell)-Pt(Cluster) Nanocubes, Qing-Ning Jiang, Huan Li, Ning Yang, Ping-Ping Fang, Feng-Ru Fan, Zhong-Qun Tian

Journal of Electrochemistry

Gold nanocubes were synthesized by a two-step seed-mediated growth method. The Aucore-Pdshell and Au_core-Pd_shell-Pt_cluster nanocubes with controllable shell thickness of Pd and cluster coverage of Pt were synthesized by simply changing the amount ratio of H₂PdCl₄ or H₂PtCl₆. The samples were characterized by scanning electron microscope (SEM) , transmission electron microscopc (TEM) and cyclic voltammetry (CV). CV was then used to make a systematic study on the dependence of the electrocatalytic properties on the shell thickness of Au_core-Pd_shell and Pt coverage of Au_core-Pd …

Hydrogen Evolution Reaction Activtity Of Ni-Ru-Ir Oxide Cathode Coating, Yin-Hui Fu, Xue-Ming Li, Wu-Lin Li, Jun Zhang

Journal of Electrochemistry

The Ni-Ru-Ir electrode coating was fabricated by thermal decomposition and oxidation. Electrochemical properties of Ni-Ru-Ir electrode coating and pure nickel cathode in the 30% NaOH solutions at 90 ℃(conditions of the industrial electrolysis) ,have been investigated by cyclic voltammetry,Tafel curves and chronoamperometry. The results show that the Ni-Ru-Ir oxide electrode coating exhibited high catalytic activity. At the current density of 0. 3 A·cm^-2,the lowest hydrogen evolution overpotential of Ni-Ru-Ir oxide electrode coating was about 300 mV lower than Ni. The roughness and excharge current density of Ni-Ru-Ir electrode coating were 32 and 4 times,respectively,larger than those of pure …

Synthesis And Electrochemical Properties Of Li3V2(Po4)3/C Cathode Materials For Lithium Ion Battery, Li-Ying Liu, Hai-Yan Zhang, Lian Chen, Yu-Chun Zhai

Journal of Electrochemistry

Cathode material Li₃V₂(PO₄) ₃ /C for Lithium-ion battery was synthesized by combination of ball milling and baking. Physical and electrochemical performances of as-prepared materials were characterized through XRD,EIS and galvanostatic cell cycling. The results show that the products were monoclinic Li₃ V₂ (PO₄) ₃ with well-developed crystal structure. At 0. 1C,0. 25C and 0. 5C,the initial discharge capacities were 150. 6,134. 1 and 107. 1 mAh·g^-1 ,respectively. Capacity retention rates were 87. 3% after 130 cycles at 0. 25C and 87. 2% after 105 cycles at 0. 5C. Charge-discharge …

Nano-Sized Au On Nickel Foam As Cathode Of Alkaline Al-H2O2 Semi Fuel Cell, Shu-Li Chen, Bang-An Lu, Yao Liu, Gui-Ling Wang, Dian-Xue Cao

Journal of Electrochemistry

Nano-sized Au particles were deposited on a nickel foam substrate by a fast spontaneous deposition method using AuCl₃ as the source of Au. The effects of AuCl₃ concentration and deposition time on the size and distribution of Au particles,and the performance of the obtained Au/Ni electrode as the cathode of Al-H₂O₂ semi fuel cell were investigated. It was found that after the nickel foam was immersed in a 2 mmol·L^-1 AuCl₃ solution for 60 s,Au particles with diameters smaller than 100 nm were deposited on its surfaces and cover the surface completely. The …

Optimization Of Membrane Electrode Assembly In Air-Breathing Direct Methanol Fuel Cell, Liang Ma, Wei-Wei Cai, Jing Zhang, Liang Liang, Jian-Hui Liao, Chang-Peng Liu, Wei Xing

Journal of Electrochemistry

The structure and performance of MEA were optimized by tailoring the catalyst layer,cathodic microporous layer (MPL) ,anodic MPL and membrane,with the considerations of unique characteristics of airbreathing direct methanol fuel cell (DMFC) such as methanol crossover and cathode flooding. It was found that high catalyst loading could suppress the methanol crossover effectively,but too high catalyst loading can lead to high mass transport resistance. Hydrophobic anodic MPL with 30% (by mass) PTFE could facilitate the CO₂ bubble detachment,which decreased the methanol concentration gradient and suppressed the methanol crossover accordingly. When Nafion 115 was used as membrane,methanol crossover was severe,while Nafion …

Synthesis Of Cosalen Composite In Apo-5 And Its Electrocatalytic Behaviour For Reaction Of Dioxygen Reduction, Rong Zhang, Li-Hua Tang, Bin-Bin Fan, Jing-Hong Ma, Rui-Feng Li

Journal of Electrochemistry

CoAPO-5 molecular sieve was hydrothermally synthesized. The Cobalt ions in CoAPO-5 were coordinated with the SALEN ligend diffusing into the channels of the molecular sieve to form CoSALEN complexes. The electrochemical behaviors and electrocatalysis for dioxygen reduction of the CoSALEN complex immobilized in APO-5 modified glassy carbon electrodes (GCEs) have been investigated by cyclic voltammetry (CV) and chronoamperometry (CA) in differrent pH aqueous solutions. The results showed that the PS/CoSALEN/APO-5 /GC modified electrode is of the high electrocatalytic activity towards dioxygen reduction in pH 6. 86 buffer solution with a reduced overpotential of 447 mV lower than bare GC electrode. …

Comparison Of Various Measurement Techniques For Characterizing The Hydrodynamics Of Gas-Solid Fluidized Beds, Rahmat Sotudeh-Gharebagh, Navid Mostoufi, Reza Zarghami, Mojgan Abbasi, Nasim Salehi-Nik

The 13th International Conference on Fluidization - New Paradigm in Fluidization Engineering

There are various techniques to characterize the hydrodynamic of fluidized beds. Nowadays, sensor development is widely used to determine the hydrodynamic state of a fluidized bed to improve control and safety of the operation of such reactors. The objective of this study was to compare the advantages and disadvantages of the intrusive and novel non-intrusive techniques. The measurement techniques investigated in this work were vibration of the bed, acoustic emission and pressure. Extensive measurements were carried out at different superficial gas velocities with different particle sizes. Vibration and acoustic emissions were recorded at 25 KHz for 30 s using accelerometer …

Preface, Sang Done Kim, Yong Kang, Jea Keun Lee, Yong Chil Seo

The 13th International Conference on Fluidization - New Paradigm in Fluidization Engineering

PREFACE

Bubble-Free Fluidization Of Particles In The Voids Of A Packing Of Coarse Spheres, Bruno Formisani, Rossella Girimonte, Patrizia Bafaro, Vincenzino Vivacqua

The 13th International Conference on Fluidization - New Paradigm in Fluidization Engineering

Confining a bed of relatively fine particles in a packing of coarse spheres prevents the onset of bubbly flow past their point of incipient fluidization. To improve present representations of confined fluidization, experiments on several cuts of solids of various density are analysed and interpreted by adapting some fundamental relationships of the fluidization theory to the peculiar geometry provided by the confining environment.

Motion Of A Large Object In A 2d Bubbling Fluidized Bed, Antonio Soria-Verdugo, L. M. García-Gutiérrez, S. Sanchez-Delgado, U. Ruiz-Rivas

The 13th International Conference on Fluidization - New Paradigm in Fluidization Engineering

The motion of a large object in a bubbling fluidized bed is experimentally studied using digital image analysis. A wide range of fluidized bed applications involves the motion of large objects within the bed, such objects being reactants, catalysts, agglomerates, etc.

The experiments were run in a 2D bubbling fluidized bed with glass spheres as bed material. The object motion is measured using tracking techniques, while independent measurements of the dense phase velocity (using PIV) and bubble velocity were carried out. The effect of the excess gas velocity on the object motion was also analyzed.

It is generally accepted that …

Particle Clusters In Fluidized Beds, Ray Cocco, Frank Shaffer, S.B. Reddy Karri, Roy Hays, Ted Knowlton

The 13th International Conference on Fluidization - New Paradigm in Fluidization Engineering

Accurately predicting the entrainment rate is important in designing a commercial fluidized bed. However, most correlations fall short in providing an accurate prediction of the entrainment rate. Many correlations assume that smaller particles have a higher entrainment rate than larger particles; but, this is often not the case. Smaller particles can, and often do, have lower effective entrainment rates than larger particles. This has been presumed from several different experiments. In one case, the entrainment rate of FCC catalyst fines was measured at different fluidized bed heights and found that higher entrainment fluxes were observed at lower bed heights (i.e., …

Investigation Of The Shifting-Parameter As A Function Of Particle Size Distribution In A Fluidized Bed Traversing From A Fixed To Fluidized Bed, Christo Rautenbach, M.C. Melaaen, B.M. Halvorsen

The 13th International Conference on Fluidization - New Paradigm in Fluidization Engineering

Accurate predictions of pressure drops in fluidized beds are of great importance in the industry. Up to date no satisfactory correlation exists to predict the pressure drop in a fluidized bed as the bed is traversing from one regime to another. In the present study the powered addition correlation [1] is investigated for this particular application. It has been found that this correlation is well suited for the investigated application.

Table Of Contents, Sang Done Kim, Yong Kang, Jea Keun Lee, Yong Chil Seo

The 13th International Conference on Fluidization - New Paradigm in Fluidization Engineering

No abstract provided.

Multiple Orifice Bubble Generation In Gas-Solid Fluidized Beds: The Activation Region Approach, Sergio Sanchez Delgado, J.V. Briongos, A. Acosta-Iborra, D. Santana

The 13th International Conference on Fluidization - New Paradigm in Fluidization Engineering

This work addresses the bubble generation mechanism at multi-orifice distributors in gas-solid fluidized beds (FB). Different measurements techniques such as high speed video camera and Kistler pressure transducers were applied to obtain information from both local, and global bed dynamics. Pressure fluctuation time series are used for dynamic diagnosis of the 2-D facility used during the study. The bed was operated with different distributor plates at several bubbling conditions leading to different bubble flow patterns characterized by digital image analysis of both the dense and the bubble phases.

In order to explain the bubble pattern developed within the bed and …

Mixing Behavior And Hydrodynamic Study Of Gassolid-Solid Fluidization System: Co-Fluidization Of Fcc And Coarse Particles, Zeeshan Nawaz, Yujian Sun, Yue Chu, Fei Wei

The 13th International Conference on Fluidization - New Paradigm in Fluidization Engineering

Gas-solid-solid (GSS) fluidization system is a unique piece of equipment and its features related to better mixing quality. The mixing and hydrodynamic behavior of FCC particles with coarse particles is investigated in 2D and 3D cofluidized beds. The reason of enhancing mixing and fluidization properties by adding coarse particles is particularly due to the movement of coarse particles, those breaks the strong interparticle forces between FCC particles and destroy bubble wake (bubble disassociation strategy), time to time. The attrition mass was measured by using Zeeshan relationship at designated conditions.

Gas And Solid Mixing In A Three Partitioned Fluidized Bed, Gyoung Tae Jin, Seung-Yong Lee, Young-Ju Seo, Solim Kang, Ho-Jung Ryu

The 13th International Conference on Fluidization - New Paradigm in Fluidization Engineering

There are many gas-solid reaction systems which take place simultaneously in a single reactor, such as coal gasification. By splitting the reactions, high concentrated gases can be obtained without separation processes. Dual fluidized bed was proposed for this purpose. Similarly, simultaneous adsorption/desorption systems with dry sorbent for CO2 capture and the gasification reaction system with a char combustor and a gasifier separately were developed.

For improving gas and solid mixing efficiencies of the dual fluidized beds, a hitherto unknown partitioned fluidized bed (PFB) is proposed. A basic concept of PFB is that lower parts between two separated fluidized beds are …