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Processes, Volume 2, Issue 1 (March 2014), Pages 1-332

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Editorial

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Open AccessEditorial Acknowledgement to Reviewers of Processes in 2013
Processes 2014, 2(1), 216-217; doi:10.3390/pr2010216
Received: 26 February 2014 / Accepted: 26 February 2014 / Published: 26 February 2014
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Abstract The editors of Processes would like to express their sincere gratitude to the following reviewers for assessing manuscripts in 2013. [...] Full article

Research

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Open AccessArticle Preparation and Characterization of the TiO2 Immobilized Polymeric Photocatalyst for Degradation of Aspirin under UV and Solar Light
Processes 2014, 2(1), 12-23; doi:10.3390/pr2010012
Received: 1 September 2013 / Revised: 2 December 2013 / Accepted: 6 December 2013 / Published: 27 December 2013
Cited by 9 | PDF Full-text (809 KB) | HTML Full-text | XML Full-text
Abstract
The traditional use of TiO2 powder as a photocatalyst for degradation of organic compounds has several post-degradation treatment problems, such as filtration, precipitation, etc. A novel method was developed to immobilize TiO2 to minimize/eliminate such problems. Polymeric membrane was used
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The traditional use of TiO2 powder as a photocatalyst for degradation of organic compounds has several post-degradation treatment problems, such as filtration, precipitation, etc. A novel method was developed to immobilize TiO2 to minimize/eliminate such problems. Polymeric membrane was used as a base material, over which the TiO2 photocatalyst was immobilized as a thin layer. Preparation and characterization of five different types of polymeric/TiO2 film photocatalysts were elucidated. The catalysts’ films were cross-linked by physical, chemical, and combination of these two processes. The polymers used in the formulation of the catalysts membranes are nontoxic in nature (approved by the World Health Organization (WHO) and Food and Drug Administration (FDA). The morphology of the films were studied by SEM. Photocatalytic degradation of acetylsalicylic acid was carried out to study the efficacy and efficiency of the polymeric membrane based TiO2 as photocatalysts under both UV and solar light irradiation. The degradation was observed to be dependent on the catalyst loading as well as the film thickness. The effects of the types of cross-link bonds on the photocatalytic degradation were also investigated. Full article
(This article belongs to the Special Issue Feature Papers) Print Edition available
Open AccessArticle Rapid Determination of Optimal Conditions in a Continuous Flow Reactor Using Process Analytical Technology
Processes 2014, 2(1), 24-33; doi:10.3390/pr2010024
Received: 5 November 2013 / Revised: 13 December 2013 / Accepted: 16 December 2013 / Published: 27 December 2013
Cited by 2 | PDF Full-text (609 KB) | HTML Full-text | XML Full-text
Abstract
Continuous flow reactors (CFRs) are an emerging technology that offer several advantages over traditional batch synthesis methods, including more efficient mixing schemes, rapid heat transfer, and increased user safety. Of particular interest to the specialty chemical and pharmaceutical manufacturing industries is the significantly
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Continuous flow reactors (CFRs) are an emerging technology that offer several advantages over traditional batch synthesis methods, including more efficient mixing schemes, rapid heat transfer, and increased user safety. Of particular interest to the specialty chemical and pharmaceutical manufacturing industries is the significantly improved reliability and product reproducibility over time. CFR reproducibility can be attributed to the reactors achieving and maintaining a steady state once all physical and chemical conditions have stabilized. This work describes the implementation of a smart CFR with univariate physical and multivariate chemical monitoring that allows for rapid determination of steady state, requiring less than one minute. Additionally, the use of process analytical technology further enabled a significant reduction in the time and cost associated with offline validation methods. The technology implemented for this study is chemistry and hardware agnostic, making this approach a viable means of optimizing the conditions of any CFR. Full article
Open AccessArticle Model-Based Optimization of Scaffold Geometry and Operating Conditions of Radial Flow Packed-Bed Bioreactors for Therapeutic Applications
Processes 2014, 2(1), 34-57; doi:10.3390/pr2010034
Received: 18 September 2013 / Revised: 5 December 2013 / Accepted: 19 December 2013 / Published: 3 January 2014
Cited by 4 | PDF Full-text (1625 KB) | HTML Full-text | XML Full-text
Abstract
Radial flow perfusion of cell-seeded hollow cylindrical porous scaffolds may overcome the transport limitations of pure diffusion and direct axial perfusion in the realization of bioengineered substitutes of failing or missing tissues. Little has been reported on the optimization criteria of such bioreactors.
[...] Read more.
Radial flow perfusion of cell-seeded hollow cylindrical porous scaffolds may overcome the transport limitations of pure diffusion and direct axial perfusion in the realization of bioengineered substitutes of failing or missing tissues. Little has been reported on the optimization criteria of such bioreactors. A steady-state model was developed, combining convective and dispersive transport of dissolved oxygen with Michaelis-Menten cellular consumption kinetics. Dimensional analysis was used to combine more effectively geometric and operational variables in the dimensionless groups determining bioreactor performance. The effectiveness of cell oxygenation was expressed in terms of non-hypoxic fractional construct volume. The model permits the optimization of the geometry of hollow cylindrical constructs, and direction and magnitude of perfusion flow, to ensure cell oxygenation and culture at controlled oxygen concentration profiles. This may help engineer tissues suitable for therapeutic and drug screening purposes. Full article
(This article belongs to the Special Issue Design of Bioreactor Systems for Tissue Engineering)
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Open AccessCommunication Scale-up of the Reversible Addition-Fragmentation Chain Transfer (RAFT) Polymerization Using Continuous Flow Processing
Processes 2014, 2(1), 58-70; doi:10.3390/pr2010058
Received: 7 November 2013 / Revised: 10 December 2013 / Accepted: 12 December 2013 / Published: 8 January 2014
Cited by 8 | PDF Full-text (904 KB) | HTML Full-text | XML Full-text
Abstract
A controlled radical polymerization process using the Reversible Addition-Fragmentation Chain Transfer (RAFT) approach was scaled up by a factor of 100 from a small laboratory scale of 5 mL to a preparative scale of 500 mL, using batch and continuous flow processing. The
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A controlled radical polymerization process using the Reversible Addition-Fragmentation Chain Transfer (RAFT) approach was scaled up by a factor of 100 from a small laboratory scale of 5 mL to a preparative scale of 500 mL, using batch and continuous flow processing. The batch polymerizations were carried out in a series of different glass vessels, using either magnetic or overhead stirring, and different modes of heating: Microwave irradiation or conductive heating in an oil bath. The continuous process was conducted in a prototype tubular flow reactor, consisting of 6 mm ID stainless steel tubing, fitted with static mixers. Both reactor types were tested for polymerizations of the acid functional monomers acrylic acid and 2-acrylamido-2-methylpropane-1-sulfonic acid in water at 80 °C with reaction times of 30 to 40 min. By monitoring the temperature during the exothermic polymerization process, it was observed that the type and size of reactor had a significant influence on the temperature profile of the reaction. Full article
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Open AccessArticle A Multiwell Disc Appliance Used to Deliver Quantifiable Accelerations and Shear Stresses at Sonic Frequencies
Processes 2014, 2(1), 71-88; doi:10.3390/pr2010071
Received: 13 September 2013 / Revised: 25 November 2013 / Accepted: 20 December 2013 / Published: 10 January 2014
Cited by 3 | PDF Full-text (495 KB) | HTML Full-text | XML Full-text
Abstract
To mimic in vivo vibration of vocal fold cells, we studied the controllability and range of frequency, acceleration, duration, and shear stress in a new bioreactor attachment. The custom multiwell disc appliance fits into a commercially built rheometer, together termed a torsional rheometer
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To mimic in vivo vibration of vocal fold cells, we studied the controllability and range of frequency, acceleration, duration, and shear stress in a new bioreactor attachment. The custom multiwell disc appliance fits into a commercially built rheometer, together termed a torsional rheometer bioreactor (TRB). Previous attachments to the TRB were capable of 50–100 Hz vibrations at relatively high strains but were limited to single-sample experiments. The TRB-multiwell disc system accommodates 20 samples in partially fluid-filled wells in an aseptic environment delivering three different acceleration conditions to different samples simultaneously. Frequency and amplitude used to calculate acceleration along with duration and shear stress were controllable and quantifiable using a combination of built-in rheometer sensors, manufacturer software, and smooth particle hydrodynamics (SPH) simulations. Computed shear stresses at the well bottom using SPH in two and three dimensions were verified with analytical approximations. Results demonstrate capabilities of the TRB-multiwell disc system that, when combined with computational modeling, provide quantifiable vibration parameters covering frequencies 0.01–250 Hz, accelerations of 0.02–300 m/s2, and shear stresses of 0.01–1.4 Pa. It is well-suited for studying cell function underlying vocal fold lamina propria homeostasis, inflammation, and wound healing under differential vibration conditions. Full article
(This article belongs to the Special Issue Design of Bioreactor Systems for Tissue Engineering)
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Open AccessArticle A Multi-Scale Hybrid CFD-DEM-PBM Description of a Fluid-Bed Granulation Process
Processes 2014, 2(1), 89-111; doi:10.3390/pr2010089
Received: 18 December 2013 / Revised: 8 January 2014 / Accepted: 8 January 2014 / Published: 21 January 2014
Cited by 8 | PDF Full-text (1941 KB) | HTML Full-text | XML Full-text
Abstract
In this study, a hybrid multi-scale model has been developed for a continuous fluid bed wet granulation process by dynamically coupling computational fluid dynamics (CFD) with a discrete element model (DEM) and population balance model (PBM). In this process, the granules are formed
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In this study, a hybrid multi-scale model has been developed for a continuous fluid bed wet granulation process by dynamically coupling computational fluid dynamics (CFD) with a discrete element model (DEM) and population balance model (PBM). In this process, the granules are formed by spraying the liquid binder on the fluidized powder bed. The fluid flow field has been solved implementing CFD principles and the behavior of the solid particles has been modeled using DEM techniques whereas the change in particle size has been quantified with the help of PBM. The liquid binder droplets have been modeled implicitly in DEM. A detailed understanding of the process aids in the development of better design, optimization and control strategies. The model predicts the evolution of important process variables (i.e., average particle diameter, particle size distribution (PSD) and particle liquid content) over time, which have qualitative similarity with experimentally observed trends. The advantage of incorporating the multi-scale approach is that the model can be used to study the distributions of collision frequencies, particle velocity and particle liquid content in different sections of the fluid bed granulator (FBG), in a more mechanistic manner. Full article
Open AccessArticle Reduced Models in Chemical Kinetics via Nonlinear Data-Mining
Processes 2014, 2(1), 112-140; doi:10.3390/pr2010112
Received: 23 September 2013 / Revised: 10 December 2013 / Accepted: 19 December 2013 / Published: 23 January 2014
Cited by 6 | PDF Full-text (5734 KB) | HTML Full-text | XML Full-text
Abstract
The adoption of detailed mechanisms for chemical kinetics often poses two types of severe challenges: First, the number of degrees of freedom is large; and second, the dynamics is characterized by widely disparate time scales. As a result, reactive flow solvers with detailed
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The adoption of detailed mechanisms for chemical kinetics often poses two types of severe challenges: First, the number of degrees of freedom is large; and second, the dynamics is characterized by widely disparate time scales. As a result, reactive flow solvers with detailed chemistry often become intractable even for large clusters of CPUs, especially when dealing with direct numerical simulation (DNS) of turbulent combustion problems. This has motivated the development of several techniques for reducing the complexity of such kinetics models, where, eventually, only a few variables are considered in the development of the simplified model. Unfortunately, no generally applicable a priori recipe for selecting suitable parameterizations of the reduced model is available, and the choice of slow variables often relies upon intuition and experience. We present an automated approach to this task, consisting of three main steps. First, the low dimensional manifold of slow motions is (approximately) sampled by brief simulations of the detailed model, starting from a rich enough ensemble of admissible initial conditions. Second, a global parametrization of the manifold is obtained through the Diffusion Map (DMAP) approach, which has recently emerged as a powerful tool in data analysis/machine learning. Finally, a simplified model is constructed and solved on the fly in terms of the above reduced (slow) variables. Clearly, closing this latter model requires nontrivial interpolation calculations, enabling restriction (mapping from the full ambient space to the reduced one) and lifting (mapping from the reduced space to the ambient one). This is a key step in our approach, and a variety of interpolation schemes are reported and compared. The scope of the proposed procedure is presented and discussed by means of an illustrative combustion example. Full article
(This article belongs to the Special Issue Feature Papers) Print Edition available
Open AccessArticle Enhanced Performance of Oxidation of Rosalva (9-decen-1-ol) to Costenal (9-decenal) on Porous Silicon-Supported Silver Catalyst in a Microstructured Reactor
Processes 2014, 2(1), 141-157; doi:10.3390/pr2010141
Received: 24 November 2013 / Revised: 9 January 2014 / Accepted: 16 January 2014 / Published: 29 January 2014
Cited by 1 | PDF Full-text (1036 KB) | HTML Full-text | XML Full-text
Abstract
The use of metal-assisted HF chemical etching as a convenient technique to produce a few microns thick porous layer in silicon microchannels was demonstrated. Gas phase selective oxidation of rosalva to its aldehyde (costenal) was performed in glass/silicon microstructured reactors at temperatures of
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The use of metal-assisted HF chemical etching as a convenient technique to produce a few microns thick porous layer in silicon microchannels was demonstrated. Gas phase selective oxidation of rosalva to its aldehyde (costenal) was performed in glass/silicon microstructured reactors at temperatures of 375–475 °C on silver catalyst which was deposited on both porous and flat silicon surface by sputter-coating. The effects of temperature (375–475 °C), rosalva concentration (1.17%–3.43%), O2 to rosalva ratio (0.5–20) and residence time on the reaction were investigated. The reactivity of rosalva on the porous silicon supported silver was 5.7–6.4 times higher than on the thin film silver catalyst at 450 °C. Furthermore, activation energy for the porous silicon supported silver was lower. Isothermal conditions in the microreactors allowed high conversion and selectivity to be achieved in a wide range of temperature and oxygen concentration. At typical reaction conditions (1.75% rosalva, O2/rosalva = 3, residence time 18 ms and 450 °C), conversion of 97% and selectivity of 95% to costenal was achieved, corresponding to a turnover frequency of 268 h−1. Full article
Open AccessCommunication Microflow Photochemistry—Photodecarboxylations in Microformats
Processes 2014, 2(1), 158-166; doi:10.3390/pr2010158
Received: 19 December 2013 / Revised: 17 January 2014 / Accepted: 21 January 2014 / Published: 29 January 2014
Cited by 6 | PDF Full-text (361 KB) | HTML Full-text | XML Full-text
Abstract
This article summarizes selected examples of intra- and intermolecular photodecarboxylations involving phthalimides in a commercially available dwell device. Compared to batch conditions in a larger chamber reactor, the investigated transformations in the microreactor furnished higher conversions and yields after significantly shorter reaction times.
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This article summarizes selected examples of intra- and intermolecular photodecarboxylations involving phthalimides in a commercially available dwell device. Compared to batch conditions in a larger chamber reactor, the investigated transformations in the microreactor furnished higher conversions and yields after significantly shorter reaction times. The product qualities were commonly higher under flow conditions thus avoiding the need for further purifications. Full article
Open AccessArticle Towards a Tissue-Engineered Ligament: Design and Preliminary Evaluation of a Dedicated Multi-Chamber Tension-Torsion Bioreactor
Processes 2014, 2(1), 167-179; doi:10.3390/pr2010167
Received: 3 January 2014 / Revised: 7 February 2014 / Accepted: 10 February 2014 / Published: 19 February 2014
Cited by 4 | PDF Full-text (1439 KB) | HTML Full-text | XML Full-text
Abstract
Tissue engineering may constitute a promising alternative to current strategies in ligament repair, providing that suitable scaffolds and culture conditions are proposed. The objective of the present contribution is to present the design and instrumentation of a novel multi-chamber tension-torsion bioreactor dedicated to
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Tissue engineering may constitute a promising alternative to current strategies in ligament repair, providing that suitable scaffolds and culture conditions are proposed. The objective of the present contribution is to present the design and instrumentation of a novel multi-chamber tension-torsion bioreactor dedicated to ligament tissue engineering. A preliminary biological evaluation of a new braided scaffold within this bioreactor under dynamic loading is reported, starting with the development of a dedicated seeding protocol validated from static cultures. The results of these preliminary biological characterizations confirm that the present combination of scaffold, seeding protocol and bioreactor may enable us to head towards a suitable ligament tissue-engineered construct. Full article
(This article belongs to the Special Issue Design of Bioreactor Systems for Tissue Engineering)
Open AccessArticle Analysis of Multi-Loop Control Structures of Dividing-Wall Distillation Columns Using a Fundamental Model
Processes 2014, 2(1), 180-199; doi:10.3390/pr2010180
Received: 11 November 2013 / Revised: 23 January 2014 / Accepted: 11 February 2014 / Published: 24 February 2014
Cited by 1 | PDF Full-text (1222 KB) | HTML Full-text | XML Full-text
Abstract
Dividing-wall columns (DWCs) have significant potential as energy-efficient processes for the separation of multicomponent mixtures. However, in addition to an efficient steady state design, dynamics and control also play a major part for the success of a technology. This is especially so for
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Dividing-wall columns (DWCs) have significant potential as energy-efficient processes for the separation of multicomponent mixtures. However, in addition to an efficient steady state design, dynamics and control also play a major part for the success of a technology. This is especially so for complex distillation systems. This paper investigates the dynamics of a dividing wall column used for the separation of ternary mixtures. A detailed dynamic first principles-based model of the column I s developed in gPROMS. The model is used to generate data used for control loop pairing via the Relative Gain Array (RGA), and controller parameters are found by using Internal Model Control (IMC) tuning. The best control structures for DWC systems, involving four different ternary mixtures, and two different feed compositions for each mixture, are investigated. Full article
Open AccessArticle Absorption and Chemisorption of Small Levitated Single Bubbles in Aqueous Solutions
Processes 2014, 2(1), 200-215; doi:10.3390/pr2010200
Received: 30 November 2013 / Revised: 28 January 2014 / Accepted: 28 January 2014 / Published: 24 February 2014
Cited by 2 | PDF Full-text (459 KB) | HTML Full-text | XML Full-text
Abstract
The absorption and chemisorption of small bubbles with N2 or CO2 were investigated experimentally in aqueous and alkaline solutions. Different bubble sizes were studied ranging from 0.1 to 2.5 mm in alkaline concentrations of 0.1 mM to 1 M NaOH. The
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The absorption and chemisorption of small bubbles with N2 or CO2 were investigated experimentally in aqueous and alkaline solutions. Different bubble sizes were studied ranging from 0.1 to 2.5 mm in alkaline concentrations of 0.1 mM to 1 M NaOH. The experiments were conducted in a device consisting of a converging microchannel with a down flowing liquid. Levitation positions of single bubbles were optically characterized. A correlation was developed for the drag force coefficient, CD, including wall effects based on the force equilibrium. A linear decrease of bubble diameters was identified with and without chemical reaction, which is referred to as a rigid bubble surface area. Measured Sherwood numbers agree well with the literature values for the investigated Reynolds number range. Full article
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Open AccessArticle Interpretation of Cellular Imaging and AQP4 Quantification Data in a Single Cell Simulator
Processes 2014, 2(1), 218-237; doi:10.3390/pr2010218
Received: 22 July 2013 / Revised: 21 January 2014 / Accepted: 22 January 2014 / Published: 4 March 2014
Cited by 2 | PDF Full-text (1644 KB) | HTML Full-text | XML Full-text
Abstract
The goal of the present study is to integrate different datasets in cell biology to derive additional quantitative information about a gene or protein of interest within a single cell using computational simulations. We propose a novel prototype cell simulator as a quantitative
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The goal of the present study is to integrate different datasets in cell biology to derive additional quantitative information about a gene or protein of interest within a single cell using computational simulations. We propose a novel prototype cell simulator as a quantitative tool to integrate datasets including dynamic information about transcript and protein levels and the spatial information on protein trafficking in a complex cellular geometry. In order to represent the stochastic nature of transcription and gene expression, our cell simulator uses event-based stochastic simulations to capture transcription, translation, and dynamic trafficking events. In a reconstructed cellular geometry, a realistic microtubule structure is generated with a novel growth algorithm for simulating vesicular transport and trafficking events. In a case study, we investigate the change in quantitative expression levels of a water channel-aquaporin 4-in a single astrocyte cell, upon pharmacological treatment. Gillespie based discrete time approximation method results in stochastic fluctuation of mRNA and protein levels. In addition, we compute the dynamic trafficking of aquaporin-4 on microtubules in this reconstructed astrocyte. Computational predictions are validated with experimental data. The demonstrated cell simulator facilitates the analysis and prediction of protein expression dynamics. Full article
(This article belongs to the Special Issue Feature Papers) Print Edition available
Open AccessArticle Ecological and Economic Assessment of Micro-/Milli-Continuous Campaign Manufacturing: The Case of Writing Ink
Processes 2014, 2(1), 238-264; doi:10.3390/pr2010238
Received: 31 December 2013 / Revised: 27 January 2014 / Accepted: 28 January 2014 / Published: 6 March 2014
Cited by 3 | PDF Full-text (1048 KB) | HTML Full-text | XML Full-text
Abstract
Many products from the fine chemicals and pharmaceuticals industries are currently manufactured batch-wise in multi-product plants. However, this processing scheme suffers from severe drawbacks, such as a high specific energy demand, cleaning costs and high staff requirements. Transferring batch into continuous campaign productions
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Many products from the fine chemicals and pharmaceuticals industries are currently manufactured batch-wise in multi-product plants. However, this processing scheme suffers from severe drawbacks, such as a high specific energy demand, cleaning costs and high staff requirements. Transferring batch into continuous campaign productions may overcome these drawbacks. Using the case of writing ink, such a continuous manufacturing scheme was developed employing micro- and milli-structured components in order to intensify certain unit operations. In this paper, an ecological and economic assessment of both production concepts considering all lifecycle stages is presented. The aim of our work is to highlight the advantages and disadvantages of the two multi-product plants and to derive recommendations for the most efficient design and operation of a continuous campaign manufacturing plant. The results show that lower environmental impacts are related to continuous processing, which is due to the option for energy integration in this case. Furthermore, in the economic assessment, continuous processing proved to be economically viable. In this case, reduced staff requirements based on a highly automated manufacturing plant are the key to lower personnel costs. In general, the results emphasize the importance of such micro-/milli-continuous multi-product plants for the future manufacturing of newly developed products in the mentioned industries. Full article
Open AccessArticle Selection of Technical Reactor Equipment for Modular, Continuous Small-Scale Plants
Processes 2014, 2(1), 265-292; doi:10.3390/pr2010265
Received: 19 December 2013 / Revised: 5 February 2014 / Accepted: 11 February 2014 / Published: 10 March 2014
Cited by 15 | PDF Full-text (951 KB) | HTML Full-text | XML Full-text
Abstract
Fast process development, flexible production and the utilization of advanced process conditions are the main goals of modular and continuous small-scale plants (MCSPs). A configurable layout of the modules and the use of predefined equipment enable a quick and reliable conceptual process development
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Fast process development, flexible production and the utilization of advanced process conditions are the main goals of modular and continuous small-scale plants (MCSPs). A configurable layout of the modules and the use of predefined equipment enable a quick and reliable conceptual process development and scale-up of continuous processes. Therefore, a computer-assisted selection methodology was developed and is presented, which allows the quick selection of plug flow reactor equipment for homogeneous liquid phase reactions. It identifies a favorable technical apparatus and the configuration in the early stages of process development. This can lead to the effective planning and guiding of scale-up experiments and closes the gap between lab and process development. Full article
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Open AccessArticle Green Process Engineering as the Key to Future Processes
Processes 2014, 2(1), 311-332; doi:10.3390/pr2010311
Received: 4 December 2013 / Revised: 7 February 2014 / Accepted: 25 February 2014 / Published: 19 March 2014
Cited by 4 | PDF Full-text (1584 KB) | HTML Full-text | XML Full-text
Abstract
Growing concern for the environment, increasing stringent standards for the release of chemicals into the environment and economic competiveness have led to more environmentally friendly approaches that have resulted in greater pollution prevention via waste reduction and efficiency maximisation. Green process engineering (GPE)
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Growing concern for the environment, increasing stringent standards for the release of chemicals into the environment and economic competiveness have led to more environmentally friendly approaches that have resulted in greater pollution prevention via waste reduction and efficiency maximisation. Green process engineering (GPE) is an important tool that could make significant contributions in the drive toward making hazardous and wasteful processes more sustainable for the benefit of the economy, environment and society. This article highlights the guidelines that could be used by scientists and engineers for designing new materials, products, processes and systems. Few examples of current and future applications of GPE, particularly in the areas of biofuels, supercritical fluids, multi-functional reactors and catalytic processes, have been presented. Full article

Review

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Open AccessReview Flotation of Biological Materials
Processes 2014, 2(1), 293-310; doi:10.3390/pr2010293
Received: 30 December 2013 / Revised: 10 February 2014 / Accepted: 11 February 2014 / Published: 12 March 2014
Cited by 1 | PDF Full-text (759 KB) | HTML Full-text | XML Full-text
Abstract
Flotation constitutes a gravity separation process, which originated from the minerals processing field. However, it has, nowadays, found several other applications, as for example in the wastewater treatment field. Concerning the necessary bubble generation method, typically dispersed-air or dissolved-air flotation was mainly used.
[...] Read more.
Flotation constitutes a gravity separation process, which originated from the minerals processing field. However, it has, nowadays, found several other applications, as for example in the wastewater treatment field. Concerning the necessary bubble generation method, typically dispersed-air or dissolved-air flotation was mainly used. Various types of biological materials were tested and floated efficiently, such as bacteria, fungi, yeasts, activated sludge, grape stalks, etc. Innovative processes have been studied in our Laboratory, particularly for metal ions removal, involving the initial abstraction of heavy metal ions onto a sorbent (including a biosorbent): in the first, the application of a flotation stage followed for the efficient downstream separation of metal-laden particles. The ability of microorganisms to remove metal ions from dilute aqueous solutions (as most wastewaters are) is a well-known property. The second separation process, also applied effectively, was a new hybrid cell of microfiltration combined with flotation. Sustainability in this field and its significance for the chemical and process industry is commented. Full article
(This article belongs to the Special Issue Advances in Bioseparation Engineering)

Other

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Open AccessTechnical Note Design and Validation of a Physiologically-Adapted Bioreactor for Tissue Engineering of the Nucleus Pulposus
Processes 2014, 2(1), 1-11; doi:10.3390/pr2010001
Received: 30 September 2013 / Revised: 20 November 2013 / Accepted: 12 December 2013 / Published: 20 December 2013
Cited by 3 | PDF Full-text (449 KB) | HTML Full-text | XML Full-text
Abstract
A novel multi-axial bioreactor was designed and developed to deliver combinations of the following dynamic mechanical stimulation conditions: hydrostatic pressure, pulsatile perfusion flow and uniaxial compression in order to mimic in vivo conditions. This mechanical arrangement simultaneously allows triaxial stimulation and characterization of
[...] Read more.
A novel multi-axial bioreactor was designed and developed to deliver combinations of the following dynamic mechanical stimulation conditions: hydrostatic pressure, pulsatile perfusion flow and uniaxial compression in order to mimic in vivo conditions. This mechanical arrangement simultaneously allows triaxial stimulation and characterization of mechanical properties of samples, in particular simulating the conditions experienced by the nucleus pulposus in vivo. A series of initial experiments were performed on this prototype system using consistent, commercially-available, three dimensional scaffolds in combination with human dermal fibroblasts. Our results show that while such bioreactors hold much promise in tissue engineering of desired organs, achieving the right combination of mechanical stimuli and other conditions required in order to enhance the final properties of the cell-scaffold systems is challenging. Full article
(This article belongs to the Special Issue Design of Bioreactor Systems for Tissue Engineering)
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