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Home>Products>Journal and Reviews>I.RE.Ch.E.>Latest issue
International Review of Chemical Engineering (Rapid Communications) - March 2010 - Papers
International Review of Chemical Engineering (Rapid Communications) - Papers
Vol. 2. n. 2, pp. 204-209
Abstract - In this work two thermal comfort indices are employed to study climate variations in Greece at three levels. Initially, newly-calculated Predicted Mean Vote index values for 35 cities in Greece for the years 2008-2009 are compared with previous ones for the years 1980-89. The comparison shows increased values, indicating the probability of a very hot decade to come. Following this the Discomfort Index is employed to show differences in climate between the north, center and south of Greece. Finally, at a more local level, it is shown how Discomfort Index values can be employed to evaluate climate differences in urban areas as well as rural. Copyright © 2010 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Discomfort Index, Greece, Predicted Mean Vote Index.
Vol. 2. n. 2, pp. 210-218
Abstract - The maintenance of Safety Instrumented System (SIS), involving the proof test procedure, is a very important phase of maintaining the functional safety of a plant all over the life time. The proof testing gives the possibility of revealing the undetected dangerous failure of a SIS. The safety standards give a draft guideline for this activity but this guideline is problematical in everyday practice because it assumes that the proof test is always perfect. However the proof test is not always perfect in practice. The imperfectness of proof testing can be especially important for valves and other mechanical parts of SIS which have great influence on the performance of safety functions in process industry. This paper suggests a new failure model which takes into account that a proof test can be imperfect not just because it does not cover every possible failure modes but because a proof tested equipment cannot be always considered “as new” as inspired by the standard. This new model gives more detailed information about the different failure modes of valves under operation, maintenance and proof testing; and it makes the SIL calculation more accurate by modeling the degradation failures. It will be showed that the new model also may have influence on the proof testing strategy. Copyright © 2010 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Proof Test, Proof Test Coverage Factor, Dangerous Undetected Failures, Degraded Failures, Final Element, Markov Model, Probability of Failure on Demand.
Vol. 2. n. 2, pp. 219-226
Abstract - This paper is an attempt to develop a mathematical model and simulation of noise radiation from refineries. Analysis of experimental results of noise radiation from the refining station was explored using Visual Basic Programming language. It was observed that simulated and experimental values to a large extent conform to the conceptualize pollutant migration pattern. Simulation result of the developed model shows that increase in distance from the refining point considerably reduced the radiated noise level. A new model for noise intensity radiating at the threshold of hearing (I0 ) is reported. Copyright © 2010 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Mathematical Model, Simulation, Ambient Temperature, Speed, Noise Intensity.
Vol. 2. n. 2, pp. 227-233
Abstract - The complexity of microbial processes, coupled with the effects of incomplete mixing and the influx of noise, makes it difficult to describe quantitatively the behavior of bioreactors under realistic conditions. By circumventing the need for phenomenological equations, neural networks offer viable descriptions of such systems. However, such networks also require large amounts of carefully screened data and long training schedules. They also have limited extrapolation capability and poor physiological fidelity. Since phenomenological models are derived from physical descriptions of cellular processes, combinations of such models with neural networks, and sometimes also fuzzy logic, have provided good portrayals of nonideal bioreactor behavior while reducing the weaknesses of both approaches. However, like neural networks themselves, different architectures are possible for hybrid neural models. The rationale, architectures and illustrative applications of hybrid models for biological reactors are discussed here, with the possibility of combining them with cybernetic models, exploiting cellular intelligence, to develop self-evolving intelligent systems for optimization and control of microbial processes. Copyright © 2010 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Biological Reactors, Nonideal Conditions, Mathematical Models, Neural Networks, Hybrid Neural Models, Self-Evolving Intelligent Systems.
Vol. 2. n. 2, pp. 234-239
Abstract - The flowfield characteristics downstream of an axisymmetric sudden expansion dump combustor model is of basic importance to designers of gas turbine and solid- fuel ramjets. Many experimental techniques such as 2D LDV measurements provide only limited discrete information at given points; especially, for the cases of complex flows such as dump combustor swirling flows. For this type of flows, usual numerical interpolating schemes appear to be unsuitable. Predictions using artificial neural networks (ANN) techniques are thus proposed and some of the results are presented in this paper and are compared with the experimental data. These techniques could be used for better designs and optimization of dump combustors. Copyright © 2010 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Swirl Flow, Dump Combustors and Artificial Neural Networks.
Abstract - Pump performance of a lab-scale air-lift system for transporting solid particles is investigated experimentally. The internal diameter of the upriser varies between two values, 28 mm and 40 mm, while its total height is 4080 mm. Plastic particles of 3/8 in. are used as solid particles. The relation between the discharged liquid flux and the flux of injected air are obtained, varying injecting air flux, particles flux, type of upriser and submergence ratio. Experimental data are obtained, which represent the triangular relationship between the flow rate of air supplied and the flow rates of water and particles discharged. The results are presented on the flow-regime map. In addition, the particle motion in the upriser is investigated in detail by means of photographic observation. The physics of the phenomena is discussed from the practical viewpoint. Copyright © 2010 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Fluid Mechanics, Mass Transfer, Multiphase Flow, Voidage, Drift-Flux Model, Air-Lift Pump, Three-Phase Flow, Regime Map.
Vol. 2. n. 2, pp. 246-250
Abstract - The design and simulation of a microscale magnetophoretic separator is presented, as part of a lab-on-chip module for non-invasive prenatal diagnosis (NIPD). The separation of fetal cells and cell free fetal DNA from maternal blood with great reproducibility and efficiency is still beyond the reach of commonly used techniques. This magnetophoretic separator is used to enhance the efficiency of the separation. The work presented here focuses on the modelling and simulation of a novel technique for the separation of fetal nucleated red blood cells (NRBCs) from the maternal circulation based on the intrinsic magnetic properties of these cells. Copyright © 2010 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: NIPD, Magnetophoresis, MEMS, Lab-On-Chip.
Vol. 2. n. 2, pp. 251-255
Abstract - Since Rare Earth Elements (REE) play a significant role in modern technology their determination in geological specimens is a matter of high importance. Whereas the quantitative determination by inductively coupled plasma – atomic emission spectrometry (ICP-AES) is already well documented, the sample preparation is still challenging. Thus a microwave assisted digestion was optimized for minerals. Different mixtures of reagents (HNO3, HCl, HClO4, H2O2) and various temperature programs were tested. Microwave assisted digestion did not lead to clear solutions, whereas a following sample preparation step in an open vessel using HClO4 resulted in a complete digestion of the minerals. The supernatant of the former and the solutions obtained by the latter sample preparation were analyzed for their REE contents by ICP-AES. No statistically significant differences were found. Thus a single microwave assisted digestion step is sufficient for the determination of REE in synchysite ore. Copyright © 2010 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Geological Samples, Microwave Assisted Digestion, Minerals, REE, Synchysite.
Vol. 2. n. 2, pp. 256-262
Abstract - This
paper discusses our recent research achievements in designing high
performance environmentally-friendly coatings technologies for improving
the corrosion resistance of the aluminum and magnesium alloys used in
automotive and aerospace industries. Aluminum alloys are used widely in
such industries due to the relatively light weight and high strength.
However, the presence of alloying elements increases the inhomogeneous
structure and hence, enhances the localized corrosion. Magnesium alloys
have many attractive mechanical properties such as stiffness to weight
ratio, ease of castability and ease of machinability. These mechanical
properties make them competitive materials to aluminum alloys in a lot
of applications. Moreover, the weight saving property of magnesium
alloys is one of the most attractive issues from environmental view
point especially in automobiles industry due to fuel consumption saving
and consequently carbon dioxide emission reduction. However, magnesium
has a very high chemical reactivity with environment especially in
presence of chloride ions and oxygen. This extensively limits the
widespread of magnesium in many applications. Copyright © 2010 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Chemical Conversion Coatings, Sol Gel Coatings, Surface Modification, Corrosion, Stannate, Silica, Ceria, Molybdate, Electrochemical Impedance Spectroscopy.
Vol. 2. n. 2, pp. 263-271
Abstract - – Protein separation behavior during adsorption chromatography is governed by system thermodynamics and kinetic factors. Hydrophobic interaction chromatography (HIC) is widely utilized since many important biological products present a quite hydrophobic character. In this work, the interaction between a set of model proteins (n = 9) and a commercial adsorbent (Phenyl Sepharose FF, high substitution, GE Healthcare) was studied via extended DLVO (XDLVO) calculations. Psychochemical properties of both separand and adsorbent were gathered by contact angle determination and zeta potential measurements. Proteins were subjected to the mentioned measurements in the hydrated and the dehydrated state, so as to simulate protein properties in a low vs. high salt concentration milieu, respectively. In HIC, protein adsorption usually take place at high concentrations of ammonium sulphate (up to 1.7M) and protein desorption occurs by decreasing salt concentration in the mobile phase. The mentioned XDLVO approach allowed the calculation of the free energy of interaction vs. distance profiles between the interacting surfaces, in the aqueous environment provided by the operating mobile phase. XDLVO calculations were correlated with the actual chromatography behavior of the studied model proteins. This correlation revealed that these proteins can be segregated in two main groups, according to surface energy calculations and elution position during chromatography: i) strong binding showing a deeper secondary minimum energy >|0.20| kT ii) and weak binding having a small secondary minimum energy <|0.12| kT, thus calculations were able to predict early or late elution from a gradient chromatography experiment; the more the calculated interaction energy, the stronger will be protein binding and the later will be the elution time. The knowledge generated from these studies will generate a better understanding of real downstream bioprocess behavior which could, in turn, facilitate process design and optimization. Copyright © 2010 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Contact Angle of Proteins, Protein Adsorption, Surface Energies of Proteins.
Vol. 2. n. 2, pp. 272-277
Abstract - The dynamics of a fully fluidized bed of group C powders subject to vertical vibration was studied in a 85 mm ID transparent perspex column. Acceleration level was set to a/g = 2. Frequency was varied in the range between 10 and 60 Hz. Two bed mass values corresponding to two different bed heights were tested. Time series of the position of the oscillating column wall and those of the oscillating bed height were obtained by means of particle image velocimetry applied to sequences of digitised images of the bed taken with the help of a high speed video camera. These time series were compared (Fig. 1) with a theoretical model which assumes the bed as a linear elastic continuum subject to viscous or frictional damping. Copyright © 2010 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Fluidization, Cohesive Powders, Mechanical Vibrations, Bode Diagrams.
Vol. 2. n. 2, pp. 278-288
Abstract - The extracellular enzymes cyclodextrin glucanotransferases produced by Bacillus circulans ATCC 21783, Bacillus pseudalcaliphilus strain 8SB and Bacillus pseudalcaliphilus strain 20RF were immobilized by covalent linking via glutaraldehyde to silanized magnetic nanoparticles treated with PEI, silanized magnetite and magnetic nanoparticles, and commercially functionalized silica nano- and microparticles in order to study the immobilization capacities of the carriers, the activity recovery and some biochemical characteristics of the enzymes after immobilization. The immobilized enzymes showed a high operational stability after twelve re-uses. The temperature optima of CGTases from alcaliphilic strains of B. pseudalcaliphilus were shifted from 60°C to 65°C after immobilization on the silica particles and magnetic nanosupports. The pH activity profiles of immobilized CGTases from Bacillus pseudalcaliphilus strains were affected by the immobilization. Both enzymes showed two pH-optima – at pH 6.0 and pH 9.0. Their maximal activities were at pH 9.0 whereas the maximal activities of the native enzymes are at pH 6.0. No significant increase of pH stability profiles was observed, whereas the thermal stabilities of immobilized GTases were superior to that of free CGTases when immobilized on aminosilane and PEI modified magnetic nanoparticles. Copyright © 2010 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Cyclodextrin Glucanotransferase, Immobilization, Magnetic, Nanoparticles.
Vol. 2. n. 2, pp. 289-292
Abstract - Electromagnetic filters (EMF) can be effectively used for the cleaning of both industrial and domestic disposals such as waste water having low concentration and micron sized of dispersed particles that show magnetic characteristics. In this work, effect of some the parameters of the filtration process, external magnetic field density, size of the filter matrix elements, filter length, filtration velocity, viscosity of the suspension and the number of the cycle the separation efficiency of micron sized particles that can be magnetised in an external magnetic field has been investigated. It has been found that filtration efficiency decreased with increasing filtration velocity, external magnetic field and suspension viscosity. Furthermore, size of the filter matrix elements and the number of the cycling processes affected the cleaning efficiency. Recycling the suspension to the filter body allowed the cleaning process to be made in a shorter equipment with a high quality factor. Copyright © 2010 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Filtration, Electromagnetism, Dispersions.
Vol. 2. n. 2, pp. 293-297
Abstract - The objective of the present work was to create a numerical model to simulate the behavior of a solid oxide fuel cell. The model developed is capable of integration with other fuel cells systems and it is independent of the physical variables of the system in terms of its theory design, and it is therefore likely to be scaled and interact with other simulated systems in the same platform. Copyright © 2010 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Simulation, Fuel Cell, SOFC.
Vol. 2. n. 2, pp. 298-304
Abstract - A new kind of attapulgite clay-supported cobalt-boride (Co-B) catalyst in portable fuel cell fields was prepared by a simple chemical reduction method. The catalytic behaviors in the hydrolysis reaction with alkaline sodium borohydride (NaBH4) solution were also investigated. The effects of NaOH concentration, NaOH concentration, reacting temperature, catalyst’s amount and recycle times on the performance of the catalysts are studied, respectively. Using attapulgite clay as the support material greatly decreases the catalyst’s cost compared to the catalyst supported by activated carbon or carbon nanotube. In particular, the activation energy for the hydrogen generation reaction is attractive, 56.32 kJ/mol. In the cycle test, from the first cycle to the ninth cycle, the average hydrogen generation rate decreases gradually from 1.27 l min-1 g-1Co-B to 0.87 l min-1 g-1 Co-B. Copyright © 2010 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Attapulgite Clay, Co-B Catalyst, Recycle Ability, Alkaline NaBH4 Solution.
Vol. 2. n. 2, pp. 305-309
Abstract - Biodiesel (alkyls esters) is a clean burning fuel derived from renewable lipid feedstock such as vegetable oil or animal fat. Glycerol is a by-product from the biodiesel production which represents 10% of product total mass. Due to the present-day high demand for biodiesel, the glycerol availability has increased, while its market price decreased substantially. The glycerol pyrolysis is a promising way to produce biofuels such as hydrogen and syngas (feedstock used in synthetic fuels production via Fisher-Tropsch reaction) and avoids its accumulation in the environment. Glycerol pyrolysis is carried out in a fixed bed reactor filled with alumina oxide. The packing material diameter was varied between 0.5-0.85 millimeters. The reaction temperature was varied in the range of 750-850°C, the reaction time from 20 to 40 min, glycerol quantity from 1 to 3 mL and flow rate of carrier gas from 10 to 50 ml/min. The process parameters listed above (factors) were used to evaluate the syngas production yield. The best results, on average, were over 80 % v/v of glycerol for gas products and among them the highest amount of gas were of H2 e CO. Besides these gases, CO2, CH4, C2H4 and C3H8 were also obtained in smaller proportions. Copyright © 2010 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Pyrolysis, Syngas, Glycerol, Biodiesel, Renewable Energy.
Vol. 2. n. 2, pp. 310-318
Abstract - The increase in heat fluxes combined with the reduction in micro-system sizes has motivated the development of more efficient thermal management techniques. The above motivation led to the design of two-phase heat spreaders. The performance constraints of conventional heat pipes can be overcome in the two-phase spreaders through ample supply of liquid to the evaporator, coupled with known boiling enhancement techniques and design constraints for orientation independent functioning. The current research studied the thermal performance of the novel two-phase spreaders by numerical simulations. Analytical models help understand the mechanism of boiling and can be used as a sizing tool in practical applications. One of the objectives of this study was to develop a semi-analytical model that builds upon the previous investigations while accurately capturing the physics involved in enhancement boiling. Copyright © 2010 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Two-Phase Flow, Micro-System, Simulation, Performance, Thermal Spreader.
Vol. 2. n. 2, pp. 319-321
Abstract - Continues
decrease in quantity of the fossil fuel and undesired environmental
effects by their usage in energy production made it compulsory going
towards to newer and clearer energy production resources. When hydrogen
was compared to the recent systems in aspects of cost, environmental
effects and efficiency, it pays attention as an alternative energy
carrier instead of the fossil fuel systems at the end of Century 21st . Copyright © 2010 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Hydrogen Storage, NaBH4, Raman Spectroscopy, TMB.
Vol. 2. n. 2, pp. 322-325
Abstract - The purpose of this study is to increase efficiency and to reduce costs by changing the process parameters. The synthesis of zinc borate has been carried out with the reaction of zinc oxide and boric acid. In this study, zinc borate production was carried out in aqueous media using commercial zinc borate as seed. Experiments have been carried out in an isolated glass beaker. Temperature is controlled using a digital temperature sensor and magnetic stirrer provides constantly stirring during the reaction. The experiments were performed in the presence of seed and without seed. The samples were filtered and dried at 105°C for 20 h. Dry, fine powdered zinc borate particles were produced under optimised conditions. The resulting high yield were formed utilizing various amounts of seed and high yield was obtained for saturated solution. The effect of varying the concentrations of seed, reaction time, the amount of water on yield have been investigated. As a result, zinc borate was analyzed with X-ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) and it was observed that the synthesis was carried out successfully. Copyright © 2010 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Crystal, Seed, Zinc Borate, Zinc Oxide.
Vol. 2. n. 2, pp. 326-328
Abstract - The coffee plant and its rosy fruits first came to the notice of humans in Kaffa, Ethipiopia sometime in the third century. There are two basic types of coffee beans: robusta and arabica. An estimated 1.5 billion cups of coffee are brewed daily around the world. All of elements in the coffee were taken by human with this high consumption. Boron is a beneficial element for plant and animal, but excess boron is toxic to humans’ health, its analysis in food is becoming increasingly important. Studies with animals and humans indicate that about 90 percent of boron is absorbed in the normal intake range. In this study the boron contents of 5 different coffee types, which are Turkish coffee, Tchibo Gold, filter coffee, decaffeinated filter coffee and Nescafe Classic were analyzed. The coffee samples were extracted with hot water at 90-100 °C and filtrated in order to determine the boron concentration by Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES) technique. Calibration curve was drawn with prepared calibration set and then samples were analyzed. Copyright © 2010 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Coffee, Boron, ICP-OES.
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