12. Artikkelit / Articles

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Browsing 12. Artikkelit / Articles by Department "Department of Biotechnology and Chemical Technology"

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  • Automated design of DNA origami
    (2016) Linko, Veikko; Kostiainen, Mauri A.
     School of Chemical Technology | B1 Kirjoitus tieteellisessä aikakauslehdessä
  • Cationic polymers for DNA origami coating – examining their binding efficiency and tuning the enzymatic reaction rates
    (2016) Kiviaho, Jenny K.; Linko, Veikko; Ora, Ari; Tiainen, Tony; Järvihaavisto, Erika; Mikkilä, Joona; Tenhu, Heikki; Nonappa; Kostiainen, Mauri A.
     School of Science | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
  • Cellular delivery of enzyme-loaded DNA origami
    (2016) Ora, Ari; Järvihaavisto, Erika; Zhang, Hongbo; Auvinen, Henni; Santos, Hélder A.; Kostiainen, Mauri A.; Linko, Veikko
     School of Chemical Technology | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
  • Control of an industrial copper solvent extraction process
    (2009) Komulainen, Tiina; Doyle III, Francis J.; Rantala, Ari; Jämsä-Jounela, Sirkka-Liisa
     School of Chemical Technology | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    A two level control strategy that stabilizes and optimizes the production of an industrial copper solvent extraction process is presented. The stabilizing layer consists of a multi-input multi-output controller or two single-input single-output controllers with additional four feedforward compensators that regulate the flow rates in the copper solvent extraction process. The optimization layer consists of an optimizer that maximizes the production of the copper solvent extraction process and gives setpoints to the controllers at the stabilizing level. The mechanistic plant models, verified with industrial data, are linearized by identifying first and higher order transfer function models from simulated PRBS data. On the basis of the linear models, the interactions of the controlled variables, and the pairing of the controlled and manipulated variables are studied and the optimizer and the controllers designed. The control strategy employing two PI-control loops or a model predictive controller and additionally four feedforward control loops is successfully tested against simulated disturbances and setpoint changes. The control strategy is also compared to the data collected from the industrial plant under manual control. With this two level control strategy the production of the copper solvent extraction process is increased by 3-5% and the process variation is decreased by 70-90% compared to the manual operation of the case industrial plant. The results gained in simulation environment are successful and encouraging for further testing in an industrial plant.
  • Custom-shaped metal nanostructures based on DNA origami silhouettes
    (2015) Shen, Boxuan; Linko, Veikko; Tapio, Kosti; Kostiainen, Mauri A.; Toppari, J. Jussi
     School of Chemical Technology | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
  • Determination of surface-accessible acidic hydroxyls and surface area of lignin by cationic dye adsorption
    (2014) Sipponen, Mika Henrikki; Pihlajaniemi, Ville; Littunen, Kuisma; Pastinen, Ossi; Laakso, Simo
     School of Chemical Technology | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    A new colorimetric method for determining the surface-accessible acidic lignin hydroxyl groups in lignocellulose solid fractions was developed. The method is based on selective adsorption of Azure B, a basic dye, onto acidic hydroxyl groups of lignin. Selectivity of adsorption of Azure B on lignin was demonstrated using lignin and cellulose materials as adsorbents. Adsorption isotherms of Azure B on wheat straw (WS), sugarcane bagasse (SGB), oat husk, and isolated lignin materials were determined. The maximum adsorption capacities predicted by the Langmuir isotherms were used to calculate the amounts of surface-accessible acidic hydroxyl groups. WS contained 1.7-times more acidic hydroxyls (0.21 mmol/g) and higher surface area of lignin (84 m2/g) than SGB or oat husk materials. Equations for determining the amount of surface-accessible acidic hydroxyls in solid fractions of the three plant materials by a single point measurement were developed. A method for high-throughput characterization of lignocellulosic materials is now available.
  • Dielectrophoretic trapping of multilayer DNA origami nanostructures and DNA origami-induced local destruction of silicon dioxide
    (2015) Shen, Boxuan; Linko, Veikko; Dietz, Hendrik; Toppari, J. Jussi
     School of Science | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
  • DNA Nanostructures as Smart Drug-Delivery Vehicles and Molecular Devices
    (2015) Linko, Veikko; Ora, Ari; Kostiainen, Mauri A.
     School of Chemical Technology | A2 Katsausartikkeli tieteellisessä aikakauslehdessä
  • DNA-Based Enzyme Reactors and Systems
    (2016) Linko, Veikko; Nummelin, Sami; Aarnos, Laura; Tapio, Kosti; Toppari, J. Jussi; Kostiainen, Mauri A.
     School of Chemical Technology | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
  • Experiments and modeling of fixed-bed debarking residue pyrolysis: The effect of fuel bed properties on product yields
    (2015) Boriouchkine, Alexandre; Sharifi, Vida; Swithenbank, Jim; Jämsä-Jounela, Sirkka-Liisa
     School of Chemical Technology | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    This paper presents a study on the fixed-bed pyrolysis of debarking residue obtained from Norway spruce. Analysis is based on the dynamic model of packed bed pyrolysis which was calibrated by determining appropriate reaction rates and enthalpies to match the model predictions with the experimental data. The model comprises mass, energy and momentum equations coupled with a rate equation that describes both the primary and secondary pyrolysis reactions. The experiments used for the model calibration determined the yields of solid, liquid and gaseous pyrolysis products as well as their compositions at three distinct holding temperatures. Subsequently, the dynamic model was used to predict the product yields and to analyze the underlying phenomena controlling the overall pyrolysis reaction in a fixed-bed reactor.
  • Impact of ball milling on maize (Zea mays L.) stem structural components and on enzymatic hydrolysis of carbohydrates
    (2014) Sipponen, Mika Henrikki; Laakso, Simo; Baumberger, Stéphanie
     School of Chemical Technology | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    The impact of ball milling on structural components of maize (Zea mays L.) stem was investigated in relation to enzymatic hydrolysis of carbohydrates. Ball milling of extractive-free maize stem material was carried out with different milling times up to 12 h. Carbohydrate conversion from ball-milled maize stem material with cellulolytic preparation Onozuka R-10 increased to 79% with increasing ball milling time up to 4 h, but did not thereafter increase further. Ball milling caused drastic depolymerization of hemicelluloses as revealed by increasing amounts of monosaccharides released in absence of enzymes. Infrared spectroscopy showed that cellulose crystallinity decreased within the first 6 h milling thereafter reaching a plateau. Thioacidolysis of solid residue fractions obtained after treatment of ball-milled samples with Onozuka R-10 suggested that no extensive degradation of lignin occurred during the milling. The effect of lignin structure on enzymatic hydrolysis of associated carbohydrates was further studied independently of cellulose crystallinity. Two lignin-carbohydrate fractions comprising hemicellulose and lignin with either high or low amount of aryl ether linkages were used as model materials. Lignins abundant in aryl ether linkages appeared more detrimental than condensed lignins to enzymatic hydrolysis of associated carbohydrates.
  • Isolation of structurally distinct lignin–carbohydrate fractions from maize stem by sequential alkaline extractions and endoglucanase treatment
    (2013) Sipponen, Mika Henrikki; Lapierre, Catherine; Méchin, Valérie; Baumberger, Stéphanie
     School of Chemical Technology | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Sequential fractionation of extractive-free maize stems was carried out using two mild alkaline extractions (0.5 and 2 M NaOH, 20 'C, 24 h) before and after endoglucanase treatment. This procedure provided two lignin–carbohydrate fractions (LC1 and LC2) recovered after each alkali treatment. LC1 and LC2 contained 39% and 8% of the total lignin amount, respectively. These two fractions contained structurally distinct lignin molecules. While the content of resistant interunit bonds in lignin was 77% in LC1, it was increased up to 98% in LC2. Not unexpectedly, both alkali-soluble fractions contained substantial amount of p-coumaric and ferulic acids ether-linked to lignins. These results outline heterogeneity of maize stem lignins related to fractionation of grass materials.
  • Metallic Nanostructures Based on DNA Nanoshapes
    (2016) Shen, Boxuan; Tapio, Kosti; Linko, Veikko; Kostiainen, Mauri A.; Toppari, J. Jussi
     School of Chemical Technology | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
  • A method for detecting non-stationary oscillations in process plants
    (2014) Tikkala, Vesa-Matti; Zakharov, Alexey; Jämsä-Jounela, Sirkka-Liisa
     School of Chemical Technology | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    This paper proposes a method for detecting oscillations in non-stationary timeseries based on the statistical properties of zero-crossings. The main development presented is atechnique to remove non-stationary trend component from the analysed signals before applyingan oscillation detection procedure. First, the method extracts the signal's baseline that is utilizedto stationarize the signal. Then, an index describing the regularity of the stationarized signal'szero-crossings is computed in order to determine the presence of oscillation. The propertiesand performance of the method are analysed in simulation studies. Furthermore, the methodis comprehensively tested with industrial data in a comparative study in which the proposedmethod is tested against other oscillation detection methods using industrial benchmark dataand in tests on paperboard machine process. Finally, the simulation and industrial results areanalysed and discussed.
  • A modular DNA origami-based enzyme cascade nanoreactor
    (2015) Linko, Veikko; Eerikäinen, Marika; Kostiainen, Mauri A.
     School of Science | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
  • One-step large-scale deposition of salt-free DNA origami nanostructures
    (2015) Linko, Veikko; Shen, Boxuan; Tapio, Kosti; Toppari, J. Jussi; Kostiainen, Mauri A.; Tuukkanen, Sampo
     School of Chemical Technology | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
  • Outline of a fault diagnosis system for a large-scale board machine
    (2012) Jämsä-Jounela, Sirkka-Liisa; Tikkala, Vesa-Matti; Zakharov, Alexey; Pozo Garcia, Octavio; Laavi, Helena; Myller, Tommi; Kulomaa, Tomi; Hämäläinen, Veikko
     School of Chemical Technology | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Global competition forces process industries to continuously optimize plant operation. One of the latest trends for efficiency and plant availability improvement is to set up fault diagnosis and maintenance systems for online industrial use. This paper presents a methodology for developing industrial fault detection and diagnosis (FDD) systems. Since model or data-based diagnosis of all components cannot be achieved online on a large-scale basis, the focus must be narrowed down to the most likely faulty components responsible for abnormal process behavior. One of the key elements here is fault analysis. The paper describes and briefly discusses also other development phases, process decomposition, and the selection of FDD methods. The paper ends with an FDD case study of a large-scale industrial board machine including a description of the fault analysis and FDD algorithms for the resulting focus areas. Finally, the testing and validation results are presented and discussed.
  • A performance optimization algorithm for controller reconfiguration in fault tolerant distributed model predictive control
    (2015) Zakharov, Alexey; Zattoni, Elena; Yu, Miao; Jämsä-Jounela, Sirkka-Liisa
     School of Chemical Technology | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    This paper presents a performance optimization algorithm for controller reconfiguration in fault tol-erant distributed model predictive control for large-scale systems. After the fault has been detectedand diagnosed, several controller reconfigurations are proposed as candidate corrective actions for faultcompensation. The solution of a set of constrained optimization problems with different actuator andsetpoint reconfigurations is derived by means of an original approach, exploiting the information onthe active constraints in the non-faulty subsystems. Thus, the global optimization problem is split intotwo optimization subproblems, which enable the online computational burden to be greatly reduced.Subsequently, the performances of different candidate controller reconfigurations are compared, andthe better performing one is selected and then implemented to compensate the fault effects. Efficacyof the proposed approach has been shown by applying it to the benzene alkylation process, which is abenchmark process in distributed model predictive control.
  • Self-Assembly of Amphiphilic Janus Dendrimers into Mechanically Robust Supramolecular Hydrogels for Sustained Drug Release
    (2015) Nummelin, Sami; Liljeström, Ville; Saarikoski, Eve; Ropponen, Jarmo; Nykänen, Antti; Linko, Veikko; Seppälä, Jukka; Hirvonen, Jouni; Ikkala, Olli; Bimbo, Luis M.; Kostiainen, Mauri A.
     School of Science | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
  • A Sino-Finnish initiative for experimental teaching practices using the Design Factory pedagogical platform
    (2013) Björklund, Tua A.; Nordström, Katrina M.; Clavert, Maria
     School of Chemical Technology | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    The paper presents a Sino-Finnish teaching initiative, including the design and experiences of a series of pedagogical workshops implemented at the Aalto-Tongji Design Factory (DF), Shanghai, China, and the experimentation plans collected from the 54 attending professors and teachers. The workshops aimed to encourage trying out interdisciplinary hands-on teaching, and enable teachers to implement their ideas for teaching development utilising the DF pedagogical platform. The majority of the participants planned teaching experimentations aiming at enhancing student understanding of curricula through various group exercises utilising concrete artefacts, but found their implementation within established practices quite challenging, highlighting the challenges of transforming strategic collaboration into grass-root activity. However, the workshops ignited widespread interest in a continuum of collaboration in teaching development, and the DF has since acted as a hub for the implementation of subsequent internationalisation efforts of the two universities, including establishing a dual-degree programme.