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clarification
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Comparing the Performance of Centrifuge, Membrane Filter and Filter Press for Clarification of Lipase Enzyme
, M.Sc. Thesis Sharif University of Technology ; Rousta Azad, Reza (Supervisor)
Abstract
Lipases (Triacyl Glycerol Acyl Hydrolase, EC.3.1.1.3) are multidimensional biocatalysts which have many applications in food industrials, dairy, fats and oils processing, detergents, synthesis of pure chemical and pharmaceutical materials, paper industrial and cosmetics. Generally, industrial enzymes are produced extracellularly, so their separation from a low-cost complex medium (usually used for production) is one of the cost stages in their production process. Filtration is the most economical method of separation in the production of enzymes, but due to the small size of colloidal particles and cell masses present in the fermentation environment, its use is subject to limitations. In...
Investigation of Transport Phenomena in Clarification of Beer by Membrane Using CFD Method
, M.Sc. Thesis Sharif University of Technology ; Soltanieh, Mohammad (Supervisor)
Abstract
During the brewing process, beer alternately goes through different chemical and biochemical reactions and solid–liquid separation stages. The clarification at the final step of brewing is a highly critical stage when it comes to producing a clear and bright beer. Recently, membrane technology has been successfully used in beer clarification, wherein Kieselguhr (diatomaceous earth) filtration is replaced by cross-flow microfiltration. The most important disadvantages of using microfiltration in clarification of beer is the fouling and flux decline during the process. The phenomenology of fouling mechanisms is still undefined and selection of an appropriate technique for flux enhancement in...
Understanding the factors controlling the interfacial failure strength of advanced high-strength steel resistance spot welds: hardness vs. fracture toughness
, Article Science and Technology of Welding and Joining ; Volume 23, Issue 6 , 2018 , Pages 520-526 ; 13621718 (ISSN) ; Sharif University of Technology
Taylor and Francis Ltd
2018
Abstract
The failure of advanced high-strength steels’ spot welds is a critical issue for automotive crashworthiness. This paper deals with understanding the underlying factors of the tensile-shear strength of automotive steels’ resistance spot welds during interfacial failure. It was found that the ratio of the fracture toughness to the hardness of the fusion zone is the critical factor governing the interfacial failure mechanism: ductile shear failure (controlled by the fusion zone hardness) vs. cleavage crack propagation (controlled by the fracture toughness). This clarification could pave the way for more accurate modelling of interfacial failure of advanced steel resistance spot welds and shed...
Synthesis, characterization and comparison of PAM, cationic PDMC and P(AM-co-DMC) based on solution polymerization
, Article Journal of Industrial and Engineering Chemistry ; Volume 17, Issue 3 , 2011 , Pages 580-586 ; 1226086X (ISSN) ; Frounchi, M ; Dadbin, S ; Sharif University of Technology
2011
Abstract
High molecular weight homopolymers of acrylamide (PAM) and (2-methacryloyloxyethyl) trimethyl ammonium chloride (PDMC) and copolymer of DMC with acrylamide (P(AM-co-DMC)) were synthesized using solution polymerization technique. The synthesized polymers were characterized by Fourier transform infrared (FTIR), 1HNMR, 13CNMR spectroscopy and differential scanning calorimetry (DSC) and viscometery. 1HNMR and 13CNMR studies confirmed the structure of the synthesized polymers. The behavior of the synthesized polymers was investigated in water-acetone and water-methanol mixtures. The plot of intrinsic viscosity of either PAM or P(AM-co-DMC) with respect to acetone (methanol)/water ratio in...
Investigation of membrane fouling in cross flow microfiltration of non-alcoholic beer and modeling of tubular membrane flow
, Article Desalination ; Volume 251, Issue 1-3 , 2010 , Pages 20-28 ; 00119164 (ISSN) ; Soltanieh, M ; Yazdanshenas, M ; Sharif University of Technology
2010
Abstract
In the present work, numerical simulation of cross flow microfiltration of non-alcoholic beer in a tubular membrane has been studied theoretically and verified experimentally. Finite element method was used as a powerful tool for simulation. The feed stream, which flows mainly tangentially to the porous membrane surface, is modeled by the Navier-Stokes equations whereas the porous wall conditions are described by the Darcy equation that relates the pressure gradient within a flow stream to the flow rate through the permeable wall. A new model that considers transient behavior of the membrane due to fouling was used to estimate the permeate flux reduction. A pilot-scale cross flow membrane...
Injecting security as aspectable NFR into software architecture
, Article 14th Asia Pacific Software Engineering Conference, ASPCE 2007, Nagoya, 4 December 2007 through 7 December 2007 ; January , 2007 , Pages 310-317 ; 15301362 (ISSN); 0769530575 (ISBN); 9780769530574 (ISBN) ; Mirian Hosseinabadi, H ; Sharif University of Technology
2007
Abstract
Complexity of the software development process is often increased by actuality of crosscutting concerns in software requirements; moreover, Software security as a particular non-functional requirement of software systems is often addressed late in the software development process. Modeling and analyzing of these concerns and especially security in the software architecture facilitate detecting architectural vulnerabilities, decrease costs of the software maintenance, and reduce finding tangled and complex components in the ultimate design. Aspect oriented ADLs have emerged to overcome this problem; however, imposing radical changes to existing architectural modeling methods is not easily...
Dead-end microfiltration of rough nonalcoholic beer by different polymeric membranes
, Article Journal of the American Society of Brewing Chemists ; Volume 68, Issue 2 , 2010 , Pages 83-88 ; 03610470 (ISSN) ; Tabatabaei Nejad, S. A. R ; Soltanieh, M ; Tavakkoli, A ; Babaluo, A. A ; Fillaudeau, L ; Sharif University of Technology
2010
Abstract
Clarification of rough nonalcoholic beer using microfiltration as an alternative to conventional filtration with filter aids presents scientific and technical challenges for the brewing industry. An experimental pilot plant was used to evaluate the permeability and selectivity of polymeric membranes in the clarification process. Cellulose acetate (CA) with pore sizes of 0.2, 0.45, 0.8, and 1.2 μm, together with cellulose nitrate (CN), nylon (NY), and polytetrafluoroethylene (PTFE) with a pore size of 0.45 μm, were used at transmembrane pressures (TMP) of 1.0 and 2.0 bar. The data corroborated that the flux values of the CA, CN, and NY membranes were almost the same and reduced drastically,...
Cross-flow microfiltration of rough non-alcoholic beer and diluted malt extract with tubular ceramic membranes: Investigation of fouling mechanisms
, Article Journal of Membrane Science ; Volume 362, Issue 1-2 , 2010 , Pages 306-316 ; 03767388 (ISSN) ; Soltanieh, M ; Tabatabaei Nejad, S. A. R ; Fillaudeau, L ; Sharif University of Technology
2010
Abstract
The clarification of rough non-alcoholic beer (RNAB) and diluted malt extract (DME) was investigated in a pilot plant consisting of a tubular ceramic membrane with nominal pore diameter of 0.45μm. The results of the primary experiments show that the concentration of suspended particles in the RNAB (∼0.05kg/m3) and DME (∼0.2kg/m3) correlates proportionally to turbidity (in NTU) with the factor of 4.45×10-4 (kgm-3NTU-1). During cross-flow microfiltration (CFMF), flux declined drastically with time due to fouling mechanisms and propensity. According to the characterizing curve of log(d2t/dV2) versus log(dt/dV), fouling is initiated by penetration of aggregates through the membrane surface,...
Contribution of fouling and gel polarization during ultrafiltration of raw apple juice at industrial scale
, Article Desalination ; Volume 258, Issue 1-3 , 2010 , Pages 194-200 ; 00119164 (ISSN) ; Tabatabaee Nezhad, S. A. R ; Soltanieh, M ; Roostaazad, R ; Khoshfetrat, A. B ; Sharif University of Technology
2010
Abstract
The flux behavior during the industrial cross-flow ultrafiltration of apple juice in a batch process was modeled using a combination of the fouling and concentration polarization models. It was observed that the major flux reduction was at the beginning and at the end of operation due to fouling and increasing solute concentration in the feed tank, respectively. The fouling phenomenon was analyzed by classical and empirical models and it was shown that the empirical one has the best correlation within less than 0.3% error for each experiment. The most significant advantage of this model is its ability to predict a steady flux, while other models predict zero flux at infinite time, which is...
Analysis of fouling and flux behavior in cross-flow microfiltration of nonalcoholic beer by ceramic membrane
, Article Sustainable Membrane Technology for Energy, Water, and Environment ; JAN , 2012 , Pages 157-167 ; 9781118024591 (ISBN) ; Tabatabaei Nejad, S. A. R ; Soltanieh, M ; Fillaudeau, L ; Sharif University of Technology
John Wiley and Sons
2012