scholarly journals A novel approach using a fouling index to evaluate NOM fouling behavior in a low pressure ultrafiltration process

2013 ◽  
Vol 14 (2) ◽  
pp. 196-204 ◽  
Author(s):  
Ping Xiao ◽  
Weijun Zhang ◽  
Feng Xiao ◽  
Zhe Bi ◽  
Dongsheng Wang
Keyword(s):  
Natural Organic Matter ◽  
Membrane Fouling ◽  
Low Pressure ◽  
Mass Balances ◽  
Novel Approach ◽  
Initial Interaction ◽  
Alkaline Cleaning ◽  
Short Time ◽  
Ultrafiltration Process ◽  
Fast Stage

A fouling index (FI) was introduced as a novel approach to investigate natural organic matter (NOM) fouling behavior in a low pressure membrane ultrafiltration process. Humic acid (HA), bovine serum albumin (BSA) and sodium alginate (SA), were used in the experiments. According to FI values, fouling was caused by NOM in two steps: a fast fouling process followed by a slow one. FI of the fast stage (FIF) was much greater than that of the slow one (FIS), showing the initial interaction would play a significant role in the fouling process over a short time. The results of mass balance suggested that a small fraction of DOC was responsible for membrane fouling caused by adsorption. Furthermore, both hydrophobic interaction and electrostatic interaction between NOM and the membrane determined the fouling behavior. Only a portion of foulants was removed after hydraulic washing. The sequence of NOM causing irreversible fouling was BSA > HA > SA, and the sequence of irreversible fouling after alkaline cleaning was SA > BSA > HA. The variations of FI values were consistent with the results of mass balances and flux recovery, which confirmed the FI was a simple and effective tool to describe the membrane fouling process.

Coagulation/flocculation/ultrafiltration for natural organic matter removal in drinking water production

2004 ◽  
Vol 4 (5-6) ◽  
pp. 215-222 ◽  
Author(s):  
A.R. Costa ◽  
M.N. de Pinho
Keyword(s):  
Drinking Water ◽  
Organic Matter ◽  
Natural Organic Matter ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Membrane Surface ◽  
Water Production ◽  
Cellulose Acetate Membranes ◽  
Wide Range ◽  
Drinking Water Production

Membrane fouling by natural organic matter (NOM), namely by humic substances (HS), is a major problem in water treatment for drinking water production using membrane processes. Membrane fouling is dependent on membrane morphology like pore size and on water characteristics namely NOM nature. This work addresses the evaluation of the efficiency of ultrafiltration (UF) and Coagulation/Flocculation/UF performance in terms of permeation fluxes and HS removal, of the water from Tagus River (Valada). The operation of coagulation with chitosan was evaluated as a pretreatment for minimization of membrane fouling. UF experiments were carried out in flat cells of 13.2×10−4 m2 of membrane surface area and at transmembrane pressures from 1 to 4 bar. Five cellulose acetate membranes were laboratory made to cover a wide range of molecular weight cut-off (MWCO): 2,300, 11,000, 28,000, 60,000 and 75,000 Da. Severe fouling is observed for the membranes with the highest cut-off. In the permeation experiments of raw water, coagulation prior to membrane filtration led to a significant improvement of the permeation performance of the membranes with the highest MWCO due to the particles and colloidal matter removal.

Membrane fouling performance of Fe-based coagulation-ultrafiltration process: Effect of sedimentation time

2021 ◽  
Vol 195 ◽  
pp. 110756
Author(s):  
Yanyan Ding ◽  
Tong Li ◽  
Kaipei Qiu ◽  
Baiwen Ma ◽  
Ruijun Wu
Keyword(s):  
Membrane Fouling ◽  
Sedimentation Time ◽  
Ultrafiltration Process

scholarly journals Experimental investigation on a novel approach for laser surface hardening modelling

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
L. Orazi ◽  
A. Rota ◽  
B. Reggiani
Keyword(s):  
Surface Hardening ◽  
Carbon Diffusion ◽  
Industrial Applications ◽  
Laser Surface ◽  
Simplified Approach ◽  
Laser Surface Hardening ◽  
Novel Approach ◽  
Laser Treatments ◽  
High Flexibility ◽  
Short Time

AbstractLaser surface hardening is rapidly growing in industrial applications due to its high flexibility, accuracy, cleanness and energy efficiency. However, the experimental process optimization can be a tricky task due to the number of involved parameters, thus suggesting for alternative approaches such as reliable numerical simulations. Conventional laser hardening models compute the achieved hardness on the basis of microstructure predictions due to carbon diffusion during the process heat thermal cycle. Nevertheless, this approach is very time consuming and not allows to simulate real complex products during laser treatments. To overcome this limitation, a novel simplified approach for laser surface hardening modelling is presented and discussed. The basic assumption consists in neglecting the austenite homogenization due to the short time and the insufficient carbon diffusion during the heating phase of the process. In the present work, this assumption is experimentally verified through nano-hardness measurements on C45 carbon steel samples both laser and oven treated by means of atomic force microscopy (AFM) technique.

Algorithmic music generation by harmony recombination with genetic algorithm

2021 ◽  
pp. 1-13
Author(s):  
Omar Lopez-Rincon ◽  
Oleg Starostenko ◽  
Alejandro Lopez-Rincon
Keyword(s):  
Genetic Algorithm ◽  
New Music ◽  
Novel Approach ◽  
Time Patterns ◽  
Algorithmic Music ◽  
Long Time ◽  
Music Generation ◽  
Music Piece ◽  
Short Time ◽  
Algorithmic Music Composition

Algorithmic music composition has recently become an area of prestigious research in projects such as Google’s Magenta, Aiva, and Sony’s CSL Lab aiming to increase the composers’ tools for creativity. There are advances in systems for music feature extraction and generation of harmonies with short-time and long-time patterns of music style, genre, and motif. However, there are still challenges in the creation of poly-instrumental and polyphonic music, pieces become repetitive and sometimes these systems copy the original files. The main contribution of this paper is related to the improvement of generating new non-plagiary harmonic developments constructed from the symbolic abstraction from MIDI music non-labeled data with controlled selection of rhythmic features based on evolutionary techniques. Particularly, a novel approach for generating new music compositions by replacing existing harmony descriptors in a MIDI file with new harmonic features from another MIDI file selected by a genetic algorithm. This allows combining newly created harmony with a rhythm of another composition guaranteeing the adjustment of a new music piece to a distinctive genre with regularity and consistency. The performance of the proposed approach has been assessed using artificial intelligent computational tests, which assure goodness of the extracted features and shows its quality and competitiveness.

Implementation of a Rig Test for Rotor/Stator Interaction of Low-Pressure Compressor Blades and Comparison of Experimental Results With Numerical Model

2020 ◽  
Author(s):  
Laura Pacyna ◽  
Alexandre Bertret ◽  
Alain Derclaye ◽  
Luc Papeleux ◽  
Jean-Philippe Ponthot
Keyword(s):  
Low Cost ◽  
Low Pressure ◽  
Angular Speed ◽  
Compressor Blades ◽  
Abradable Coating ◽  
Rotor Stator Interaction ◽  
Blade Tip ◽  
Numerical Tool ◽  
Short Time ◽  
Pressure Compressor

Abstract To investigate the contact phenomenon between the blade tip and the abradable coated casing, a rig test was designed and built. This rig test fills the following constraints: simplification of the low-pressure compressor environment but realistic mechanical conditions, ability to test several designs in short time, at low cost and repeatability. The rig test gives the opportunity to investigate the behavior of different blade designs regarding the sought phenomenon, to refine and mature the phenomenon comprehension and to get data for the numerical tool validation. The numerical tool considers a 3D finite elements model of low-pressure compressor blades with a surrounding rigid casing combined with a specialized model to take into account the effects of the wear of the abradable coating on the blade dynamics. Numerical results are in good agreement with tests in terms of: critical angular speed, blade dynamics and wear pattern on the abradable coated casing.

A Novel Approach to Nanoscale Materials Synthesis Using Industrial Laser Processing of Organosilazane Liquid Precursors

1990 ◽  
Vol 206 ◽  
Author(s):  
Tongsan D. Xiao ◽  
Peter R. Strutt ◽  
Kenneth E. Gonsalves
Keyword(s):  
Ceramic Powder ◽  
Average Diameter ◽  
Current Approach ◽  
Powder Materials ◽  
Materials Synthesis ◽  
Laser Plume ◽  
New Approach ◽  
Novel Approach ◽  
Liquid Precursors ◽  
Short Time

ABSTRACTA new approach has been developed for the synthesis of nanoscale ceramic powder materials from liquid organosilazane precursors. This technique, by exploiting fast kinetic chemical and physical reactions, makes it possible to synthesize significant quantities of material in a relatively short time. In the current approach aerosols of a silazane monomer, (CH3SiHNH)n, (n = 3 or 4), of mol. wt. 280–320, are injected into the beam of a cw industrial CO2 laser to obtain nanoscale ceramic powders. Injection of the aerosol into the laser-beam results in a high-temperature plume. Rapid condensation of the molecular precursor species emerging from the laser plume results in the formation of preceramic polymer particles, with an average diameter of 62 nm. One attractive feature of this process is that 70 wt.% of the liquid precursor is converted into nanoscale powders. Another feature is that only a further 10 wt.% loss occurs during post thermal treatment to form the end-product.

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