Processes

11 pages, 449 KiB

Open AccessTechnical Note

Design and Validation of a Physiologically-Adapted Bioreactor for Tissue Engineering of the Nucleus Pulposus

by May Win Naing^1,*, Yang Liu¹, Immanuel Sebastine¹, David Dingmann², Chrysanthi Williams² and David J. Williams^1,*

¹ Healthcare Engineering Research Group, Centre for Biological Engineering, Loughborough University, Loughborough LE11 3TU, UK

² ElectroForce Systems Group, Bose Corporation, Eden Prairie, MN 55346, USA

Processes 2014, 2(1), 1-11; https://doi.org/10.3390/pr2010001 - 20 Dec 2013

Cited by 5 | Viewed by 7286

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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12 pages, 809 KiB

Open AccessArticle

Preparation and Characterization of the TiO₂ Immobilized Polymeric Photocatalyst for Degradation of Aspirin under UV and Solar Light

by Debjani Mukherjee, Shahzad Barghi and Ajay K. Ray^*

Department of Chemical and Biochemical Engineering, Western University, London, ON N6A5B9, Canada

Processes 2014, 2(1), 12-23; https://doi.org/10.3390/pr2010012 - 27 Dec 2013

Cited by 41 | Viewed by 10750

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 [...] Read more.

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)

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10 pages, 609 KiB

Open AccessArticle

Rapid Determination of Optimal Conditions in a Continuous Flow Reactor Using Process Analytical Technology

by Michael F. Roberto¹, Thomas I. Dearing², Charles W. Branham², Olav Bleie^3,4 and Brian J. Marquardt^2,*

¹ Department of Chemistry, University of Washington, 4000 15th Ave NE, Seattle, WA 98105, USA

² Applied Physics Laboratory, University of Washington, 1013 NE 40th Street, Seattle, WA 98105, USA

³ Tel-Tek, Kjølnes Ring 30, Porsgrunn 3918, Norway

⁴ Department of Chemistry, University of Bergen, P.O. Box 7800, Bergen NO-5020, Norway

Processes 2014, 2(1), 24-33; https://doi.org/10.3390/pr2010024 - 27 Dec 2013

Cited by 6 | Viewed by 9741

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 [...] Read more.

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

(This article belongs to the Special Issue Design and Engineering of Microreactor and Smart-Scaled Flow Processes)

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24 pages, 1625 KiB

Open AccessArticle

Model-Based Optimization of Scaffold Geometry and Operating Conditions of Radial Flow Packed-Bed Bioreactors for Therapeutic Applications

by Danilo Donato, Ilaria E. De Napoli and Gerardo Catapano^*

Department of Environmental, Territory and Chemical Engineering, University of Calabria, Via P. Bucci, 87030 Rende (CS), Italy

Processes 2014, 2(1), 34-57; https://doi.org/10.3390/pr2010034 - 3 Jan 2014

Cited by 8 | Viewed by 7813

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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13 pages, 904 KiB

Open AccessCommunication

Scale-up of the Reversible Addition-Fragmentation Chain Transfer (RAFT) Polymerization Using Continuous Flow Processing

by Nenad Micic^1,2,†, Alan Young^1,2,†, Julien Rosselgong¹ and Christian H. Hornung^1,*

¹ CSIRO Materials Science and Engineering, Bayview Avenue, Clayton, VIC 3168, Australia

² Chemical Engineering Faculty, Monash University, Wellington Road, Clayton, VIC 3169, Australia

^† These authors contributed equally to this work.

Processes 2014, 2(1), 58-70; https://doi.org/10.3390/pr2010058 - 8 Jan 2014

Cited by 28 | Viewed by 13413

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 [...] Read more.

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

(This article belongs to the Special Issue Design and Engineering of Microreactor and Smart-Scaled Flow Processes)

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18 pages, 495 KiB

Open AccessArticle

A Multiwell Disc Appliance Used to Deliver Quantifiable Accelerations and Shear Stresses at Sonic Frequencies

by Sarah A. Klemuk^1,*, Sarah Vigmostad^2,†, Kalyan Endapally^2,†, Andrew P. Wagner^2,† and Ingo R. Titze^1,3,†

¹ Communication Sciences and Disorders, the University of Iowa, Iowa City, IA 52242, USA

² Department of Biomedical Engineering, the University of Iowa, Iowa City, IA 52242, USA

³ National Center for Voice and Speech, University of Utah, Salt Lake City, UT 84112, USA

^† These authors contributed equally to this work.

Processes 2014, 2(1), 71-88; https://doi.org/10.3390/pr2010071 - 10 Jan 2014

Cited by 3 | Viewed by 6946

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 [...] Read more.

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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23 pages, 1941 KiB

Open AccessArticle

A Multi-Scale Hybrid CFD-DEM-PBM Description of a Fluid-Bed Granulation Process

by Maitraye Sen, Dana Barrasso, Ravendra Singh and Rohit Ramachandran^*

Department of Chemical and Biochemical Engineering, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA

Processes 2014, 2(1), 89-111; https://doi.org/10.3390/pr2010089 - 21 Jan 2014

Cited by 75 | Viewed by 12565

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 [...] Read more.

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

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29 pages, 5734 KiB

Open AccessArticle

Reduced Models in Chemical Kinetics via Nonlinear Data-Mining

by Eliodoro Chiavazzo^1,2

, Charles W. Gear¹, Carmeline J. Dsilva¹, Neta Rabin³ and Ioannis G. Kevrekidis^1,4,*

¹ Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA

² Energy Department, Politecnico di Torino, Torino 10129, Italy

³ Department of Exact Sciences, Afeka Tel-Aviv Academic College of Engineering, Tel-Aviv 69107, Israel

⁴ Program in Applied and Computational Mathematics, Princeton University, Princeton, NJ 08544, USA

Processes 2014, 2(1), 112-140; https://doi.org/10.3390/pr2010112 - 23 Jan 2014

Cited by 43 | Viewed by 8932

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 [...] Read more.

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)

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17 pages, 1036 KiB

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

by Enhong Cao¹, Ioannis Zuburtikudis^2,3, Noor Al-Rifai¹, Mark Roydhouse¹ and Asterios Gavriilidis^1,*

¹ Department of Chemical Engineering, University College London, Torrington Place, London WC1E 7JE, UK

² Department of Mechanical and Industrial Design Engineering, T.E.I. of Western Macedonia, Kozani 50100, Greece

³ Department of Chemical and Petroleum Engineering, United Arab Emirates University, Al Ain, P.O.Box: 15551, UAE

Processes 2014, 2(1), 141-157; https://doi.org/10.3390/pr2010141 - 29 Jan 2014

Cited by 6 | Viewed by 9474

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 [...] Read more.

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

(This article belongs to the Special Issue Design and Engineering of Microreactor and Smart-Scaled Flow Processes)

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9 pages, 361 KiB

Open AccessCommunication

Microflow Photochemistry—Photodecarboxylations in Microformats

by Michael Oelgemöller^1,*

, Sonia Gallagher^2,† and Kevin McCarthy^2,†

¹ James Cook University, School of Pharmacy and Molecular Sciences, Townsville, Queensland 4811, Australia

² Dublin City University, School of Chemical Sciences, Dublin 9, Ireland

^† These authors contributed equally to this work.

Processes 2014, 2(1), 158-166; https://doi.org/10.3390/pr2010158 - 29 Jan 2014

Cited by 9 | Viewed by 12600

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. [...] Read more.

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

(This article belongs to the Special Issue Design and Engineering of Microreactor and Smart-Scaled Flow Processes)

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13 pages, 1439 KiB

Open AccessArticle

Towards a Tissue-Engineered Ligament: Design and Preliminary Evaluation of a Dedicated Multi-Chamber Tension-Torsion Bioreactor

by Cédric P. Laurent^1,*,†

, Cédryck Vaquette^2,†, Céline Martin³, Emmanuel Guedon³, Xiude Wu⁴, Alain Delconte¹, Dominique Dumas⁵, Sébastien Hupont⁶, Natalia De Isla⁵, Rachid Rahouadj¹ and Xiong Wang⁵

¹ CNRS, LEMTA, UMR 7563, Université de Lorraine, 2 Avenue de la Forêt de Haye, 54504 Vandeuvre-lès-Nancy, France

² Institute of Health and Biomedical Innovation, Queensland University of Technology, Cnr Blamey Street & Musk Avenue, Kelvin Grove Brisbane, Queensland 4059, Australia

³ CNRS, LRGP, UMR 7274, Université de Lorraine, 2 Avenue de la Forêt de Haye, 54504 Vandeuvre-lès-Nancy, France

⁴ Department of Electromechanical Engineering, School of Mechanical Engineering, Yangtze University, 1 Xueyuan Road, Jingzhou 434023, China

⁵ CNRS, IMoPA, UMR 7365, Biopôle, Université de Lorraine, 9 Avenue de la Forêt de Haye, 54504 Vandeuvre-lès-Nancy, France

⁶ PTIBC-IBISA, CNRS, FR3209, Biopôle, Université de Lorraine, 9 Avenue de la Forêt de Haye, 54504 Vandeuvre-lès-Nancy, France

^† These authors contributed equally to this work.

Processes 2014, 2(1), 167-179; https://doi.org/10.3390/pr2010167 - 19 Feb 2014

Cited by 20 | Viewed by 10721

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 [...] Read more.

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)

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20 pages, 1222 KiB

Open AccessArticle

Analysis of Multi-Loop Control Structures of Dividing-Wall Distillation Columns Using a Fundamental Model

by Salvador Tututi-Avila^1,2, Arturo Jiménez-Gutiérrez² and Juergen Hahn^1,*

¹ Department of Biomedical Engineering, Department of Chemical & Biological Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180-3590, USA

² Departamento de Ingeniería Química, Instituto Tecnológico de Celaya, Ave. Tecnológico y García Cubas S/N, Celaya 38010, Gto., Mexico

Processes 2014, 2(1), 180-199; https://doi.org/10.3390/pr2010180 - 24 Feb 2014

Cited by 13 | Viewed by 18409

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 [...] Read more.

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

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16 pages, 459 KiB

Open AccessArticle

Absorption and Chemisorption of Small Levitated Single Bubbles in Aqueous Solutions

by Alexander Tollkötter and Norbert Kockmann^*

TU Dortmund University, BCI, Equipment Design, Emil-Figge-Straße 68, D-44227 Dortmund, Germany

Processes 2014, 2(1), 200-215; https://doi.org/10.3390/pr2010200 - 24 Feb 2014

Cited by 7 | Viewed by 7903

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 [...] Read more.

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, C_D, 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

(This article belongs to the Special Issue Design and Engineering of Microreactor and Smart-Scaled Flow Processes)

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2 pages, 112 KiB

Open AccessEditorial

Acknowledgement to Reviewers of Processes in 2013

by Processes Editorial Office

MDPI AG, Klybeckstrasse 64, CH-4057 Basel, Switzerland

Processes 2014, 2(1), 216-217; https://doi.org/10.3390/pr2010216 - 26 Feb 2014

Viewed by 3610

Abstract

The editors of Processes would like to express their sincere gratitude to the following reviewers for assessing manuscripts in 2013. [...] Full article

20 pages, 1644 KiB

Open AccessArticle

Interpretation of Cellular Imaging and AQP4 Quantification Data in a Single Cell Simulator

by Seon B. Kim, Ying Hsu and Andreas A. Linninger^*

Laboratory for Product and Process Design, Department of Bioengineering, University of Illinois at Chicago, 851 South Morgan St. 218 SEO, Chicago, IL 60607, USA

Processes 2014, 2(1), 218-237; https://doi.org/10.3390/pr2010218 - 4 Mar 2014

Cited by 2 | Viewed by 8689

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 [...] Read more.

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)

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27 pages, 1048 KiB

Open AccessArticle

Ecological and Economic Assessment of Micro-/Milli-Continuous Campaign Manufacturing: The Case of Writing Ink

by Laura Grundemann^*,† and Stephan Scholl

¹ Institut für Chemische und Thermische Verfahrenstechnik, Technische Universität Braunschweig, Langer Kamp 7, 38106 Braunschweig, Germany

^† Current address: Evonik Industries AG, CREAVIS-Science to Business, Paul-Baumann-Strasse 1, 45764 Marl, Germany

Processes 2014, 2(1), 238-264; https://doi.org/10.3390/pr2010238 - 6 Mar 2014

Cited by 7 | Viewed by 8316

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 [...] Read more.

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

(This article belongs to the Special Issue Design and Engineering of Microreactor and Smart-Scaled Flow Processes)

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28 pages, 951 KiB

Open AccessArticle

Selection of Technical Reactor Equipment for Modular, Continuous Small-Scale Plants

by Nicolai Krasberg^1,†, Lukas Hohmann^2,†, Thomas Bieringer¹, Christian Bramsiepe³ and Norbert Kockmann^2,*

¹ INVITE GmbH, CHEMPARK, Building W32, D-51368 Leverkusen, Germany

² Laboratory of Equipment Design, BCI, TU Dortmund University, Emil-Figge-Straße 68, D-44227 Dortmund, Germany

³ Laboratory of Plant and Process Design, BCI, TU Dortmund University, Emil-Figge-Straße 70, D-44227 Dortmund, Germany

^† These authors contributed equally to this work.

Processes 2014, 2(1), 265-292; https://doi.org/10.3390/pr2010265 - 10 Mar 2014

Cited by 45 | Viewed by 10173

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 [...] Read more.

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

(This article belongs to the Special Issue Design and Engineering of Microreactor and Smart-Scaled Flow Processes)

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18 pages, 759 KiB

Open AccessReview

Flotation of Biological Materials

by George Z. Kyzas^1,2

and Kostas A. Matis^2,*

¹ Department of Petroleum and Natural Gas Technology, Technological Educational Institute of Kavala, Kavala GR-654 04, Greece

² Division of Chemical Technology & Industrial Chemistry, Department of Chemistry, Aristotle University of Thessaloniki, Thessaloniki GR-541 24, Greece

Processes 2014, 2(1), 293-310; https://doi.org/10.3390/pr2010293 - 12 Mar 2014

Cited by 8 | Viewed by 11916

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)

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Processes, Volume 2, Issue 1 (March 2014) – 19 articles , Pages 1-332

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