Recent advances in membrane bioreactors (MBRs): membrane fouling and membrane material.

A mini-review on membrane fouling

Anaerobic membrane bioreactors have potential for energy-efficient treatment of domestic and other wastewaters, membrane fouling being a major hurdle to application. It was found that fouling can be controlled if membranes are placed directly in contact with the granular activated carbon (GAC) in an anaerobic fluidized bed bioreactor (AFMBR) used here for post-treatment of effluent from another anaerobic reactor treating dilute wastewater. A 120-d continuous-feed evaluation was conducted using this two-stage anaerobic treatment system operated at 35 °C and fed a synthetic wastewater with chemical oxygen demand (COD) averaging 513 mg/L. The first-stage was a similar fluidized-bed bioreactor without membranes (AFBR), operated at 2.0−2.8 h hydraulic retention time (HRT), and was followed by the above AFMBR, operating at 2.2 h HRT. Successful membrane cleaning was practiced twice. After the second cleaning and membrane flux set at 10 L/m2/h, transmembrane pressure increased linearly from 0.075 to only 0.1 bar...

Anaerobic Fluidized Bed Membrane Bioreactor for Wastewater Treatment

The demand for portable gas sensors is increasing following the progress in the electronics industry; there is an equal need to increase the quality of gas sensors. Spinel ferrites have been used as electronic materials for more than 50 years and offer a suitable ceramic base for the gas sensor market. They are simple, low cost, and compared to other gas sensors have structural and compositional versatility. This review highlights the recent developments and shows the potential of the spinel ferrites on gas sensor technology. Sensing mechanisms for a range of gasses and humidity are explained for n-type, p-type, mixed and substituted spinel ferrite gas sensors. The change in conduction mechanism is discussed outlining electronic and chemical sensitization that both increase the conductivity. Some cation substitutions are shown to change the oxidation state, thereby increasing sensitivity, but noble metals are shown to chemically sensitize spinel ferrites. This review surveys synthesis methods for producing spinel ferrites and discusses future prospects for further improvements.

Spinel ferrite oxide semiconductor gas sensors

Finite-time stability analysis of fractional order time-delay systems: Gronwall's approach

A membrane bioreactor (MBR) combines membrane separation and biological treatment, normally involving the activated sludge process, in municipal wastewater treatment. Despite excellent performance over years of full‐scale operation, the interactions between microbes and the membrane in the MBR process, which determine its design and operational criteria, remain unclear. This report reviewed research regarding how numerous process parameters impact biofouling rates and, in particular, the possible contribution of microbial products to biofouling. This study also characterized different fractions of microbial products and assessed their potential affect on membrane fouling.

Biofouling in Membrane Bioreactor

A new expression for the evaluation of the electric force acting on a colloidal particle in an applied electric field is derived under the condition of weak applied electric field. The expression derived, which is based on the Maxwell stress tensor, is applicable to both rigid and soft particles for various types of surface conditions and to both symmetric and asymmetric geometries. We show that, depending upon the electrophoresis conditions, the electric force evaluated by the methods commonly used in the literature can be overestimated, thereby leading to incorrect electrophoretic mobility.

Evaluation of the electric force in electrophoresis.

INTRODUCTION Classification of Finely Dispersed Systems AM Spasic, M Mitrovic, and DN Krstic GENERAL Overview Charged Particles and Droplets: Overview H Ohshima Electrokinetic Phenomena in Suspensions AV Delgado and F Gonzalez-Caballero Emulsions: Overview LL Schramm and EN Stasiuk Hydrodynamics and Heat or Mass Transfer in Finely Dispersed Systems A Saboni and S Alexandrova Various Approaches and Transitions Interactions of Nanostructured Fillers with Polymer Networks: Transition from Nano- to Macroscale M Plavsic Atomic Scale Imaging of Oscillation and Chemical Waves at Catalytic Surface Reactions: Experimental and Statistical Lattice Models VI Elokhin and VV Gorodetskii Characterization of the Catalysts by Means of an Oscillatory Reaction L Kolar-Anic', S Anic', and Z Cupic' The Polymer Conformational Stability and Transitions: A Quantum Decoherence Theory Approach M Dugic', D Rakovic', and M Plavsic Reality and Compatibility of Physical and Mathematical Formalisms JP Jaric' and DS Kuzmanovic' Tools Nonlinear Frequency Response Method for Investigation of Equilibria and Kinetics of Adsorption Systems M Petkovska Current Principles of Mixing JY Oldshue Quantification of Visual Information PB Jovanic' HOMO-AGGREGATE FINELY DISPERSED SYSTEMS Emulsions Non-Newtonian Effects on Particle Size in Mixing Systems JY Oldshue Theory of Electroviscoelasticity AM Spasic, MP Lazarevic, and DN Krstic Production of Monodispersed Emulsions Using Shirasu Porous Glass Membranes GT Vladisavljevic, M Shimizu, T Nakashima, H Schubert, and M Nakajima Dispersoids Mechanochemical Treatment of Inorganic Solids: Solid-Solid Fine Dispersions M Zdujic' Liquid-Liquid Dispersions Reactive Extraction in Electric Fields H-J Bart HETERO-AGGREGATE FINELY DISPERSED SYSTEMS Foams Gas Bubbles within Electric Fields P Creux, J Lachaise, and A Graciaa Fluosols Structures and Substructures in Spray Pyrolysis Process: Nanodesigning V Jokanovic Polymer Membranes Transfer Phenomena Through Polymer Membranes S Alexandrova, DN Amang, F Garcia, V Rollet, and A Saboni Multiphase Dispersed Systems Gas-Flowing Solids -Fixed Bed Contactors AP Dudukovic' and NM Nikac?evic' Reaction and Capillary Condensation in Dispersed Porous Particles NM Ostrovskii and J Wood Particle Production Using Supercritical Fluids D Skala and A Orlovic HETERO-AGGREGATE FINELY DISPERSED SYSTEMS OF BIOLOGICAL INTEREST Biocolloids Effects of Electrical Field on the Behavior of Biological Cells Y-C Kuo and J-P Hsu Modeling Mesoscopic Fluids with Discrete-Particles: Methods, Algorithms, and Results W Dzwinel, K Boryczko, and DA Yuen Nonlinear Dynamics of DNA Chain: Peyrard-Bishop-Dauxois Model S Zdravkovic' Surface Modification of Dispersed Phases Designed for In Vivo Removal of Overdosed Toxins R Partch, E Powell, Y-H Lee, M Varshney, D Shah, R Baney, D-W Lee, D Dennis, T Morey, and J Flint Carbon Nanocapsules and Nuclear Applications EE Pasqualini and M Lopez Bioencapsulation in Polymer Micro- and Nanocarriers and Applications in Biomedical Fields E Markvicheva Electrostatic Droplet Generation Technique for Cell Immobilization BM Bugarski, B Obradovic, VA Nedovic, and MFA Goosen Micro-Biosensor Based on Immobilized Cells L Mojovic and GN Jovanovic INDEX

Finely Dispersed Particles : Micro-, Nano-, and Atto-Engineering

Introduction Classification of Finely Dispersed Systems Classification Based on Scales Classification Based on Geometry Classification Based on Origin of Forces Classification Based on Physical-Chemical Processes Classification Based on Entities General Historical Review and Motivation Pilot Plant for Uranium Extraction from Wet Phosphoric Acid Entrainment Problems in Solvent Extraction: Performance of Demulsions Marangoni Instabilities of the First and Second Order and a Possible Electrical Analog Rheology: Various Constitutive Models of Liquids Electroviscosity and Electroviscoelasticity of Liquid-Liquid Interfaces Particular Theory of Electroviscoelasticity Previous Work Structure: Electrified Interfaces-a New Constitutive Model of Liquids Dynamics: Physical Formalism Mathematical Formalisms Appendix Experimental Experimental Experimental Confirmation Results and Discussion Assembled Measured, Calculated, and Estimated Data Conclusions Implications The First Philosophical Breakpoint The Second Philosophical Breakpoint Concluding Remarks Electrophoresis Introduction General Governing Equations Boundary Conditions Perturbation Approach Equilibrium Problem Perturbed Problem Boundary Effects Governing Equations Low Surface Potential Model Boundary Conditions Solution Procedure Analytical Solution Numerical Solution Concluding Remarks List of Symbols References Author Index Subject Index

Interfacial Electroviscoelasticity and Electrophoresis

The residence time distribution for the flow of liquid reactants containing electrolytes in a cylindrical microreactor is derived under the conditions of constant surface potential and negligible end effects. The influences of the key parameters, including the thickness of the double layer, the strength of the applied electric field, and the magnitude of the applied pressure gradient, on the behavior of residence time distribution are discussed. The results obtained provide necessary information for the design and optimization of microreactors which involve liquid electrolyte reactants. The results of the numerical simulation reveal that a thin double layer, a strong applied electric field, and a greater applied pressure gradient lead to a faster fluid flow and, therefore, a short residence time. We show that if κa ≤ 0.001 the residence time distribution can be approximated by that for the case of a laminar flow, and if κa ≥ 500, the residence time distribution can be approximated by that for the case of ...

Jyh-Ping Hsu

Papers

Biofouling in Membrane Bioreactor

Evaluation of the electric force in electrophoresis.

Finely Dispersed Particles : Micro-, Nano-, and Atto-Engineering

Interfacial Electroviscoelasticity and Electrophoresis

Residence time distribution of a cylindrical microreactor.