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  • 2351.
    Yin, Bo
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Oligomeric Isosorbide Esters as Alternative Renewable Resource Plasticizers for PVC2011In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 119, no 4, p. 2400-2407Article in journal (Refereed)
    Abstract [en]

    Oligo(isosorbide adipate) (OSA), oligo(isosorbide suberate) (OSS), and isosorbide dihexanoate (SDH) were synthesized and evaluated as renewable resource alternatives to traditional phthalate plasticizers. The structure of the synthesized oligomers was confirmed by nuclear magnetic resonance spectroscopy (H-1-and C-13-NMR), and molecular weight was determined by size exclusion chromatograph. The plasticizers were blended with poly(vinyl chloride) (PVC), and the miscibility and properties of the blends were evaluated by differential scanning calorimetry, fourier transform infrared spectroscopy, tensile testing, and thermogravimetry. Especially the blends plasticized with SDH had almost identical properties with PVC/diisooctyl phthalate (DIOP) blends. The blends containing OSA and OSS plasticizers, based on dicarboxylic acids, had somewhat lower strain at break but higher stress at break and better thermal stability compared to the PVC/DIOP or PVC/SDH blends. All the synthesized isosorbide plasticizers showed potential as alternative PVC plasticizers.

  • 2352.
    Yin, Litao
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. University of Science and Technology Beijing.
    FEM Modelling of Micro-galvanic Corrosion in Al Alloys Induced by Intermetallic Particles: Exploration of Chemical and Geometrical Effects2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Localized corrosion, such as pitting, crevice corrosion or galvanic corrosion, is a long-standing phenomenon that can greatly limit the life of metallic materials. For decades experimental methods have been used to try to understand the underlying physical, chemical and electrochemical processes that control localized corrosion in order to find effective protection methods against its propagation. The complexity of the phenomenon and its small geometric size have often severely restricted the basic understanding of local corrosion. In recent decades, computational methods have been developed as an alternative to the experimental methods. Compared to experimental methods, modeling and numerical simulation enable complicated systems to be systematically investigated without considering the inherent constraints of experimental methods.

        In the current Doctoral thesis, advanced calculation methodology has been used to study galvanic corrosion of an aluminum alloy with geometric resolution at micrometer level. The computational platform has been a commercial FEM-based software, COMSOL Multiphysics, which was combined with another software, Matlab. The current model system consists of a semi-spherical intermetallic particle, surrounded by a pure aluminum matrix. The aluminum surface is covered by an inert passive film, except for a ring-shaped surface around the particle itself. By assuming that the particle is electrochemically more noble than aluminum, it acts as a cathode and the surrounding aluminum ring as anode. By utilizing the FEM-based software, it has been possible to incorporate important physicochemical reactions, including the electrochemical anode and cathode reactions of the individual phases, mass transport of various chemical compounds formed during ongoing electrochemistry, homogeneous reactions in the electrolyte, as well as deposition of corrosion products consisting of Al(OH)3 along parts of the anodic area.

        What has made this study a significant step forward is that not only chemical changes but also geometrical changes have been taken into consideration in the simulation of ongoing micro-galvanic corrosion. Particularly challenging has been to mathematically master the gradual deposition of compact Al(OH)3 on an aluminum surface which gradually dissolves anodically. In the initial modeling work, the deposition of Al(OH)3 was assumed to occur only on the electrode surface, resulting in a gradual blockage of surface activity. In an even more advanced stage, the modeling has also sought to simulate the effect of a deposited porous film of Al(OH)3, formed through homogeneous reactions in the electrolyte. By taking into account inhibited diffusion and migration of chemical products that the porous film causes, its sterically inhibiting effect has for the first time been quantitatively interpreted. The porous corrosion product can most closely resemble the lid experimentally observed above local corrosion attacks, which leads to an even more diminished surface activity in electrochemical reactions compared with the deposition of only compact corrosion products on the anode surface.

        The kinetic model has resulted in a significantly deeper insight into the mechanism of micro-galvanic corrosion of the investigated system. The simulation has been shown to predict the time-dependent geometric changes of the anodically dissolved aluminum surface as well as the flow and distribution of generated chemical products. Contrary to the widely accepted perception that Al(OH)3 is not stable in the occluded acidified electrolyte environment, the calculations predict a higher local pH in the occluded electrolyte. This means that insoluble Al(OH)3 can be deposited on the electrode surface, the blocking effect of which may lead to a termination of the micro-galvanic corrosion. If the ring width is initially 0.5 μm or less, transport of OH- ions from the cathode surface to the occluded electrolyte environment is limited, leading to a local acidification within the occluded dissolving volume. At a given anodic ring width, an increased radius of the cathodic particle instead leads to an increased anodic dissolution rate by formation of a larger area for the cathode reaction. Variation of the chemical parameters in the electrolyte also shows that the simulated micro-galvanic corrosion rate of aluminum has a minimum at pH = 6. Both more acidic and more alkaline conditions result in an elevated anodic dissolution of aluminum. When pH ≤ 4, the deposition of Al(OH)3  becomes negligible, and the micro-galvanic corrosion will continue uninterrupted, completely in accordance with experimental data.

  • 2353.
    Yin, Litao
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science. Univ Sci & Technol Beijing, China.
    Jin, Ying
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Pan, Jinshan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    A FEM model for investigation of micro-galvanic corrosion of Al alloys and effects of deposition of corrosion products2016In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 192, p. 310-318Article in journal (Refereed)
    Abstract [en]

    A finite element method model has been elaborated aiming at a deeper insight into the influence of microstructure on micro-galvanic corrosion of Al alloys. The model considers a dynamic corroding surface and takes into account kinetic data from local electrochemical reactions, transport of O-2 and ionic species (e.g., Al3+, H+, Cl-), homogeneous reactions in the electrolyte, deposition of reaction products and its influence on both anodic and cathodic reactions. As a first step, an Al matrix with a micrometer-sized cathodic intermetallic particle exposed in 0.1 M NaCl has been considered. The simulation predicts the dynamic changes of the corroding surface, and the flow and distribution of ionic species and of O-2 in space and time. The calculated pH of the electrolyte inside and nearby the occluded corroding volume suggests the formation of insoluble Al(OH)(3) on both the cathodic and anodic areas. This results in blocking effects of anodic and cathodic reactions and in eventual termination of the micro-galvanic corrosion. The predicted deposition of corrosion product is in good agreement with in-situ atomic force microscopy measurements.

  • 2354.
    Yin, Litao
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science. University of Science and Technology Beijing, China.
    Jin, Ying
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Pan, Jinshan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Numerical Simulation of Micro-Galvanic Corrosion of Al Alloys: Effect of Chemical Factors2017In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 164, no 13, p. C768-C778Article in journal (Refereed)
    Abstract [en]

    A finite element model for simulating the propagation of micro-galvanic corrosion of Al alloys induced by intermetallic particle was established to reveal the dynamic changes including a moving dissolution boundary, deposition of reaction products and their blocking effect. This model has previously been used to study the influence of geometrical factors such as the particle size and width of the anodic ring. In this work, we explore effects of chemical factors including pH and bulk concentration of O-2 by using chemical-dependent electrochemical kinetics as input parameters. The simulations reveal that the micro-galvanic corrosion rate is slowest at pH = 6. For pH > 6, the rise of pH increases the dissolution rate of Al and also the deposition rate of Al(OH)(3), leading to a faster but more short localized Al dissolution. For pH < 6, the decline of pH accelerates Al dissolution and inhibits Al(OH)(3) deposition, leading to a faster and more long lasting Al dissolution. At pH <= 4, deposition of Al(OH)(3) becomes negligible, and localized corrosion will propagate continuously. Within the O-2 concentration range relevant for atmospheric conditions, a lower O-2 concentration in the solution leads to a slower rate of micro-galvanic corrosion.

  • 2355.
    Yoshikawa, Masahiro
    et al.
    Central Research Institute of Electric Power Industry, Energy Engineering Research Laboratory, Kanagawa, Japan.
    Bodén, Andreas
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Sparr, Mari
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Experimental determination of effective surface area and conductivities in the porous anode of molten carbonate fuel cell2006In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 158, no 1, p. 94-102Article in journal (Refereed)
    Abstract [en]

    Stationary polarization curves and electrochemical impedance spectroscopy of a porous nickel anode in a molten carbonate fuel cell were obtained in order to determine the active surface area and conductivities with varying degree of electrolyte filling for two anode feed-gas compositions, one simulating operation with steam reformed natural gas and the other one gasified coal. The active surface area for coal gas is reduced by around 70-80% compared to the standard gas composition in the case of Li/Na carbonate. Moreover, an optimal degree of electrolyte filling was shifted toward higher filling degree in the case of operation with coal gas.In order to evaluate the experimental data a one-dimensional model was used. The reaction rate at the matrix/electrode interface is about five times higher than the average reaction rate in the whole electrode in case of 10% electrolyte filling. This result suggests that the lower limit of the filling degree of the anode should be around 15% in order to avoid non-uniform distribution of the reaction in the electrode. Therefore, in the case of applying Li/Na carbonate in the MCFC, an electrolyte distribution model taking into account the wetting properties of the electrode is required in order to set an optimal electrolyte filling degree in the electrode.

  • 2356. Yoshimura, Takeshi
    et al.
    Hayashi, Akiko
    Handa-Narumi, Mai
    Yagi, Hirokazu
    Ohno, Nobuhiko
    Koike, Takako
    Yamaguchi, Yoshihide
    Uchimura, Kenji
    Kadomatsu, Kenji
    Sedzik, Jan
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology. National Institutes of Natural Sciences, Japan.
    Kitamura, Kunio
    Kato, Koichi
    Trapp, Bruce D.
    Baba, Hiroko
    Ikenaka, Kazuhiro
    GlcNAc6ST-1 regulates sulfation of N-glycans and myelination in the peripheral nervous system2017In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, article id 42257Article in journal (Refereed)
    Abstract [en]

    Highly specialized glial cells wrap axons with a multilayered myelin membrane in vertebrates. Myelin serves essential roles in the functioning of the nervous system. Axonal degeneration is the major cause of permanent neurological disability in primary myelin diseases. Many glycoproteins have been identified in myelin, and a lack of one myelin glycoprotein results in abnormal myelin structures in many cases. However, the roles of glycans on myelin glycoproteins remain poorly understood. Here, we report that sulfated N-glycans are involved in peripheral nervous system (PNS) myelination. PNS myelin glycoproteins contain highly abundant sulfated N-glycans. Major sulfated N-glycans were identified in both porcine and mouse PNS myelin, demonstrating that the 6-O-sulfation of N-acetylglucosamine (GlcNAc-6-O-sulfation) is highly conserved in PNS myelin between these species. P-0 protein, the most abundant glycoprotein in PNS myelin and mutations in which at the glycosylation site cause Charcot-Marie-Tooth neuropathy, has abundant GlcNAc-6-O-sulfated N-glycans. Mice deficient in N-acetylglucosamine-6-O-sulfotransferase-1 (GlcNAc6ST-1) failed to synthesize sulfated N-glycans and exhibited abnormal myelination and axonal degeneration in the PNS. Taken together, this study demonstrates that GlcNAc6ST-1 modulates PNS myelination and myelinated axonal survival through the GlcNAc-6-O-sulfation of N-glycans on glycoproteins. These findings may provide novel insights into the pathogenesis of peripheral neuropathy.

  • 2357.
    Yu, Fiona
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Sulfur Addition to Reduce CO Emissions2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In autumn 2017, an experiment was conducted for the reduction of carbon

    monoxide (CO) emissions commissioned by Holmen Paper Braviken, one

    of the world’s most production-efficient paper mills. Digitalization has increased

    in recent years, which has resulted in a decreased demand for graphic

    paper. The goal of finding cost-reducing solutions in the manufacturing process

    has been increased in Holmen Paper Braviken to meet the rising price

    pressure and strengthen competitiveness. Braviken consumes large quantities

    of steam in the paper machines and some of this steam is produced in

    the solid fuel boiler. The solid fuel boiler combusts bark, wood chips, and

    water treatment sludge. When adding sulfur-rich water treatment sludge to

    the fuel mix, it has been observed that CO levels decrease without increasing

    NOx levels. To control the amount of sulfur addition, it has been proposed

    that pure sulfur can be microdosed into the fuel mix. A previous short-term

    experiment was conducted in Braviken during autumn 2016 with a successful

    result.

    The present study was conducted with the aim of mapping the effects of

    sulfur addition to the solid fuel boiler in Braviken concerning CO emissions.

    The possibility to operate the plant and interaction with the water treatment

    sludge have also been investigated. The study was performed through

    the construction of a microdosing system and a long-term attempt of sulfur

    addition.

    The result shows that the optimal sulfur concentration of Braviken’s solid

    fuel boiler for reducing CO emissions is 6 kg/h S (1.03 kg S/ton C). The

    interaction between elemental sulfur with the sulfur-rich water treatment

    sludge is complex, but with sulfur dosage a reduction of 42% CO can be

    achieved. NOx levels have not shown any change on the addition of sulfur.

    The study shows that CO emissions are at a more stable level with sulfur dosing.

    The result becomes difficult to analyze because the parameters varied.

    The effects of parameters should be investigated with the recommendation

    to perform a more prolonged experiment on sulfur addition.

  • 2358.
    Yu, Q. Z.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Brage, Claes O.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Nordgreen, Thomas
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Sjöström, Krister
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Effects of Chinese dolomites on tar cracking in gasification of birch2009In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 88, no 10, p. 1922-1926Article in journal (Refereed)
    Abstract [en]

    To minimize tar in the producer gas from birch gasification at 700, 750 and 800 degrees C, four Chinese dolomites (Zhenjiang, Nanjing, Shanxi, Anhui) and a Swedish dolomite (Sala) used as reference were studied in a laboratory-scale atmospheric fluidized bed gasifier. The gasifier was equipped with a downstream fixed catalyst bed. The results imply that all dolomites but Anhui dolomite effectively decompose tar into gases. Anhui dolomite showed a low catalytic capacity to crack tar produced at 700 and 800 degrees C. The influence of various ratios of steam to biomass on tar content in the producer gas after passing over dolomite was studied. The tar cracking efficiency of the dolomites did not improve significantly with the ratio of steam to biomass in the region 0.11-0.52.

  • 2359.
    Yu, Wenbin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Reitberger, Torbjörn
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Hjertberg, T.
    Oderkerk, J.
    Costa, F. R.
    Gedde, Ulf W.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Antioxidant consumption in squalane and polyethylene exposed to chlorinated aqueous media2012In: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 97, no 11, p. 2370-2377Article in journal (Refereed)
    Abstract [en]

    Squalane stabilized with 0.2 wt.% of Irganox 1010 and a medium-density polyethylene containing 0.1 wt.% of the same antioxidant were exposed to two different aqueous media (water solutions containing either 10 ppm Cl-2 or 10 ppm ClO2, both buffered to pH = 6.8) at different temperatures between 30 and 70 degrees C. The squalane phase was characterized by differential scanning calorimetry (oxidation induction time, OIT) and infrared spectroscopy, and the aqueous media were analysed after concentrating the analytes using liquid-liquid extraction by liquid chromatography, mass spectrometry and infrared spectroscopy. OIT measurements were carried out on the polyethylene samples after exposure to the chlorinated aqueous media. Exposure of the squalane systems to water containing ClO2 resulted in discolouration by the formation of quinoid structures and a faster depletion of the antioxidant than exposure to water containing Cl-2. The activation energy for the loss of antioxidant activity on exposure to ClO2-water was very low (<10 kJ mol(-1)) in the squalane test (no diffusion control) and 21 +/- 2 kJ mol(-1) at a depth of 1-2 mm from the surface of polyethylene plaques (diffusion control). Calculation from earlier published OIT data from a HDPE exposed to Cl-2-water yielded an activation energy for the loss antioxidant activity of 68 kJ mol(-1). The antioxidant degradation products obtained from the exposure to the ClO2 aqueous medium were found at a higher concentration, were more polar and exhibited a higher proportion of low molar mass species than those obtained after exposure to the Cl-2 aqueous medium. The important chemical difference between ClO2 and Cl-2 is that the former is a one-electron oxidant whereas the latter preferentially reacts by hydrogen substitution. Possible further reactions, in agreement with the observations made, are proposed.

  • 2360. Yu, Xinhai
    et al.
    Wen, Zhenzhong
    Lin, Ying
    Tu, Shan-Tung
    Wang, Zhengdong
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Intensification of biodiesel synthesis using metal foam reactors2010In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 89, no 11, p. 3450-3456Article in journal (Refereed)
    Abstract [en]

    This study presents a technology for continuous and high-efficiency alkali-catalyzed biodiesel synthesis using a metal foam reactor combined with a passive mixer. A metal foam reactor with higher pore density produces smaller droplets that result in higher efficiency of biodiesel synthesis. Compared with conventional stirred reactors, the time for high methyl ester conversion can be shortened remarkably by the use of metal foam reactors. Experimental results reveal that a metal foam reactor of 50 pores per inch exhibits an energy consumption per gram biodiesel of 1.01 J g(-1), merely 1.69% and 0.77% of energy consumption of the zigzag micro-channel and conventional stirred reactors, respectively. Moreover, biodiesel yield per reactor for the metal foam reactor is approximately 60 times that of the zigzag micro-channel reactor, thus overcoming the problem of numbering up an excessive number of reactors in the application. These results indicate the great potential of metal foam reactors in small-fuel biodiesel processing plants for distributive applications.

  • 2361. Yu, Z.
    et al.
    Rasmuson, Åke Christoffer
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Projected area of measurement volume in phase-Doppler anemometry and application for velocity bias correction and particle concentration estimation1999In: Experiments in Fluids, Vol. 27, no 2, p. 189-198Article in journal (Refereed)
  • 2362. Yu, Z.
    et al.
    Rasmuson, Åke Christoffer
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Turbulence characteristics around the agitator in a dilute suspension2001In: Journal of Chemical Engineering of Japan, Vol. 34, no 5, p. 654-661Article in journal (Refereed)
  • 2363.
    Yu, Ziyun
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Rasmuson, Åke Christoffer
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Selective desorption of carbon dioxide from sewage sludge for in-situ methane enrichment – modeling of the desorption processIn: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909Article in journal (Other academic)
  • 2364. Yuan, K.
    et al.
    Yu, Y.
    Lu, X.
    Ji, X.
    Zhu, Bin
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    A new technology for spraying advanced low-temperature (300∼600 °C) Solid oxide fuel cells2017In: Proceedings of the International Thermal Spray Conference, ASM International , 2017, p. 132-137Conference paper (Refereed)
    Abstract [en]

    Solid oxide fuel cell (SOFC) has been developed for a hundred year and met a great challenge on material design and marketing. In recent years, new SOFC materials are dug up to achieve high energy-output performance at lower working temperature (300∼600 °C), namely low-temperature SOFC (LTSOFC). In this study, Ni-Co-Al-Li oxide (NCAL) was used for making dense, thin and uniform coatings on grooved bipolar electrode substrate for LTSOFC. Low-pressure plasma spray (LPPS) technology was applied to manufacture the NCAL coatings. The performance of a fuel cell package using the coated bipolars was tested between 350 and 600 °C, showing 6∼8 W power output with 4 single fuel cells (active area of 25 cm2). The LPPS technology is believed to be one of the ultimate ways for manufacturing the thin film/coatings for SOFC applications in future. 

  • 2365. Yurindatama, D.
    et al.
    Barsoum, Imad
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures. The Petroleum Institute, United Arab Emirates.
    Constitutive model and failure locus of a polypropylene grade used in offshore intake pipes2017In: Polymer testing, ISSN 0142-9418, E-ISSN 1873-2348, Vol. 57, p. 245-259Article in journal (Refereed)
    Abstract [en]

    BorECO®™ BA212E is a polypropylene block co-polymer which has become a common material in the manufacturing of large diameter non-pressurized gravity offshore intake pipelines. These lines are used for transportation of sea water for cooling of petrochemical process plants. The pipe sections are joined by butt heat fusion welding to create the pipeline. Recently a few premature failures of such pipelines have been reported in the field. Hence, there is a need to characterize the constitutive behavior of the pipe and weld material in order to properly design these pipes. The aim of this work is to determine the material constitutive behaviors of the pipe material and the welded joint material. Uniaxial tensile tests of both the pipe and weld joint material are conducted at various strain rates. Both the pipe and weld material show a rather high strain rate dependency, with the weld material having about half the yield strength than that of the pipe material. An analytical constitutive material model is developed for both the pipe and weld material, incorporating the effect of strain rate. The failure locus, expressed in terms of the equivalent plastic strain at failure vs. the stress triaxiality, for both materials is also determined as part of the constitutive model using notched dumbbell specimens. The constitutive model and failure loci for the pipe and weld material are implemented in a finite element model (FEM) and are validated by conducting a series of independent four-point bend experiments on both material types. The validation is carried out by comparing the FEM results of the four-point bend model with the experimental results, which show a rather good agreement.

  • 2366. Zaccone, Alessio
    et al.
    Soos, Miroslav
    Lattuada, Marco
    Wu, Hua
    Bäbler, Matthäus
    Department of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering, ETH Zurich.
    Morbidelli, Massimo
    Breakup of dense colloidal aggregates under hydrodynamic stresses2009In: Physical Review E. Statistical, Nonlinear, and Soft Matter Physics, ISSN 1539-3755, E-ISSN 1550-2376, Vol. 79, no 6, p. 061401-Article in journal (Refereed)
    Abstract [en]

    Flow-induced aggregation of colloidal particles leads to aggregates with fairly high fractal dimension (d(f) similar or equal to 2.4-3.0) which are directly responsible for the observed rheological properties of sheared dispersions. We address the problem of the decrease in aggregate size with increasing hydrodynamic stress, as a consequence of breakup, by means of a fracture-mechanics model complemented by experiments in a multipass extensional (laminar) flow device. Evidence is shown that as long as the inner density decay with linear size within the aggregate (due to fractality) is not negligible (as for d(f) similar or equal to 2.4-2.8), this imposes a substantial limitation to the hydrodynamic fragmentation process as compared with nonfractal aggregates (where the critical stress is practically size independent). This is due to the fact that breaking up a fractal object leads to denser fractals which better withstand stress. In turbulent flows, accounting for intermittency introduces just a small deviation with respect to the laminar case, while the model predictions are equally in good agreement with experiments from the literature. Our findings are summarized in a diagram for the breakup exponent (governing the size versus stress scaling) as a function of fractal dimension.

  • 2367.
    Zagorodni, Andrei
    KTH, Superseded Departments, Materials Science and Engineering.
    Evaluation of results obtained by analysis of fractions2004In: Analytica Chimica Acta, ISSN 0003-2670, E-ISSN 1873-4324, Vol. 512, no 2, p. 251-256Article in journal (Refereed)
    Abstract [en]

    The paper discusses treatment of experimental data obtained from the monitoring of continuous processes by a series of batch analyses (i.e. by analysis of fractions sequentially collected during the process). Common errors that are committed when graphically representing and fitting such data are shown. An approach for identification of such errors in published data is presented. One error results from the incorrect positioning of the analysis results along the X-axis when plotting data. In the case of equal fractions, this results in a systematic error along the X-axis. For non-equal fractions, the error in the coefficients of the fitting equation can be both systematic and random. A correct representation does not introduce any error if the actual function is linear in the region of the fraction collection. This plotting method is also a satisfactory procedure for low curvature functions. Another error originates because of the incorrect application of the least squares method. The reason lies in the fact that the analysis of each fraction does not represent an instant value of the measured parameter, but rather the averaged value over some period of time or over some volume. The actual error depends on the curvature of the fitting function. Furthermore, a reader encounters difficulties when evaluating published scientific information because many authors do not explain the methods by which their data were plotted and fit. The presented approach to the evaluation of graphical data makes it possible to identify the described errors.

  • 2368.
    Zahr, Meia
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Separation of Tryptic Digested IgG with HPLC2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The antibody immunoglobulin G (IgG) can be tryptically digested into smaller peptides. This study attempted to develop a separation method for those peptides using RP-HPLC with a C18 column at room temperature. Optimizing separation of trypsin cleaved cytochrome C was used as a guideline before analyzing IgG. The optimized analysis of Cytochrome C was performed at wavelength 280nm (UV) and methanol was used as an organic solvent in mobile phase (B). A fast gradient to 100% mobile phase B with low flow rate gave favorable results for cytochrome C. A slow gradient to 100% mobile phase B was suited for IgG separation. The optimized gradient elution of cytochrome C and IgG was performed at 0.3 and 0.8 ml/min, respectively.

  • 2369. Zakrzewska, A.
    et al.
    Zaleśny, R.
    Kolehmainen, E.
    Ośmiałowski, B.
    Jȩdrzejewska, B.
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Pietrzak, M.
    Substituent effects on the photophysical properties of fluorescent 2-benzoylmethylenequinoline difluoroboranes: A combined experimental and quantum chemical study Dedication: This publication is dedicated to the memory of Prof. Jerzy Pa̧czkowski.2013In: Dyes and pigments, ISSN 0143-7208, E-ISSN 1873-3743, Vol. 99, no 3, p. 957-965Article in journal (Refereed)
    Abstract [en]

    In this study, we demonstrate a successful synergy between theory and experiment and report on the photophysical properties of a recently synthesized series of substituted 2-benzoylmethylenequinoline difluoroboranes with a view towards the effect of substitution on their properties. In general difluoroboranes are known to have a bright fluorescence but for some analogs the properties are not fully understood. Quantum chemistry methods have been applied in order to explain a complex structure of the absorption and emission spectra and to gain an insight into the charge redistribution upon the excitation of the investigated molecules. We demonstrate that the spectra of this important class of compounds can be satisfactorily simulated using quantum chemistry methods. In particular, the absorption and emission band structure was resolved and the spectral features were assigned to C-H wagging and skeletal vibrations of the polycyclic core.

  • 2370.
    Zanzi Vigouroux, Rolando
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Birbas, Daniella
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Márquez Montesino, Francisco
    niversidad de Pinar del Río, Departamento de Quimica, Pinarde de Río, Cuba,.
    Preparation of Activated Carbon: Forest residues activated with Phosphoric Acid and ZincSulfate2011In: VII EDICIÓN DE LA CONFERENCIA CIENTÍFICA INTERNACIONAL MEDIOAMBIENTE SIGLO XXI, MAS XXI 2011, 2011Conference paper (Refereed)
    Abstract [en]

    This paper describes the preparation of activated carbon by chemical activation. The selected biomass used as precursor is sawdust from both Cuban and Swedish Pine tree. Phosphoric acid and Zinc Sulphate are the chemical reagents. The objective is to study the influence of acid concentration, impregnation ratio and activation temperature on adsorption performance of the obtained activated carbon.

    The experiments with phosphoric acid activation show that treatment with 40% acid concentration at 400 °C produce an activated carbon with good properties for ammonia adsorption and good iodine number. If a 30% phosphoric acid is used for activation, an activation temperature of 500 °C is recommended. With an impregnation ratio of 1, good adsorption was obtained in the activated carbon produced from Swedish pine while using Cuban pine a higher adsorption was obtained with an impregnation ratio of 2.

    The experiments with Zinc Sulphate activation show that activation conditions of 20% zinc sulphate concentration, 400 °C and impregnation ratio: 1 are enough to produce an activated carbon with good properties for ammonia adsorption. The adsorption of carbon tetrachloride was lower. Activated carbons produced with 10 % zinc sulphate concentration, 0.5 impregnation ratio and 400 °C activation temperature (the mildest studied conditions) show already good iodine number and BET surface area.    

  • 2371.
    Zanzi Vigouroux, Rolando
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Björnbom, Emilia
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Reaction Engineering.
    Grimm, Alejandro
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Reaction Engineering.
    Biosorbentes para la remoción de cobre (II) en soluciones acuosas2005Conference paper (Refereed)
  • 2372.
    Zanzi Vigouroux, Rolando
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Majari, Mehdi
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Björnbom, Emilia
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Reaction Engineering.
    Biomass pre-treatment by torrefaction2008Conference paper (Refereed)
  • 2373.
    Zanzi Vigouroux, Rolando
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Tsyntsarski, B.
    Institute of Organic Chemistry, Bulgarian Academy of Sciences.
    Budinova, T.
    Institute of Organic Chemistry, Bulgarian Academy of Sciences.
    Petrov, N.
    Institute of Organic Chemistry, Bulgarian Academy of Sciences.
    Influence of the chemical composition of agricultural by-products on their behavior during thermal treatment2008Conference paper (Refereed)
  • 2374.
    Zavalis, Tommy Georgios
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Mathematical Models for Investigation of Performance, Safety, and Aging in Lithium-Ion Batteries2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Rechargeable lithium-ion batteries have both the power and energy capabilities to be utilized in hybrid electric vehicles and other power demanding applications. However, there are obstacles primarily related to reliability in safety and lifetime. Additionally, there is still room for improvement in the battery performance.

    In this work, physics-based mathematical models have been successfully set-up and numerically solved to investigate performance, safety, and aging in lithium-ion battery systems. This modeling approach enabled a detailed analysis of the electrochemical processes related to these issues. As the models included many parameters and spatial resolution of several variables with time or frequency, strategies for investigation needed to be developed for most of the work. The accuracy of the investigation was consolidated by the utilization of parameters characterized from experimental work.

    The performance expressed in terms of polarization was determined for a power-optimized battery cell undergoing various operating conditions. A methodology that separated and quantified the contribution of each process to the polarization was set up, allowing the study of the contributions as a snapshot in time and as an average over a cycle. Mass transport in electrolyte was shown to be a crucial feature to improve especially if the battery is expected to undergo high current-loads for long periods of time.

    Safety-concerns when a battery cell is short-circuited were investigated for three types of short-circuit scenarios. All scenarios raised the temperature to the point where exothermic side reactions were initiated. The similarities between the scenarios in temperature increase were a result of the limiting current being reached. The differences, however small, were related to the placement of the short-circuit. Especially when the current collectors were not directly connected by the short circuit, an increased electronic resistance was observed which lowered both the generated current and heat.

    The aging of a battery cell was investigated by model analysis of electrodes harvested from fresh and aged cells. A methodology was used where a frequency-dependent model was fitted to three-electrode impedance experiments by tuning parameters associated to electrode degradation. For cycled cells, electrolyte decomposition products inhibiting the mass transport in the electrolyte and particle cracking in the positive electrode increased the impedance. A similar model was also set up for investigation of the lithium intercalation processes in PAN-based carbon fibers, showing it to have both good mass transport and kinetic capabilities.

  • 2375.
    Zavalis, Tommy Georgios
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Behm, Mårten
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Investigation of Short-Circuit Scenarios in a Lithium-Ion Battery Cell2012In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 159, no 6, p. A848-A859Article in journal (Refereed)
    Abstract [en]

    A short-circuited lithium-ion battery cell is likely to generate sufficient heat to initiate exothermic side reactions causing thermal runaway. A 2D coupled electrochemical-thermal model was developed to investigate a prismatic LiNi0.8Co0.15Al0.05O2 vertical bar LiPF6, EC/EMC (3:7)vertical bar MAG-10 battery cell that is short-circuited. Three short-circuit scenarios are investigated during the events from when short circuit occurs until exothermic side reactions initiate. The scenarios are an external short circuit, a nail penetration and an impurity-induced short circuit. The model is used to predict the temperature increase within the cell and to explain how the interrelation between the electrochemical processes and the thermal properties affects the increase. Important safety measures are also examined with the model. The simulation results highlight general short-circuit characteristics and critical distinctions between the scenarios. The mass transport of lithium ions in the electrolyte is found to be the most important general characteristic that determines the rate of the temperature increase. The electric resistance distinguishes the scenarios from each other. The rate of the temperature increase is dictated by the mass transport in the electrolyte even when large variations in available active material are made and it is shown to be difficult to slow down the rate by cooling.

  • 2376.
    Zavalis, Tommy Georgios
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Klett, Matilda
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Kjell, Maria
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Behm, Mårten
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Wreland Lindström, Rakel
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Aging in Lithium-Ion Batteries: Experimental and Model Investigation of Harvested LiFePO4 and Mesocarbon Microbead Graphite Electrodes2013In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 110, p. 335-348Article in journal (Refereed)
    Abstract [en]

    This study investigates aging in LiFePO4/mesocarbon microbead graphite cells that have been subjected to either a synthetic hybrid drive cycle or calendar aging, at 22 C. The investigation involves detailed examination and comparison of harvested fresh and aged electrodes. The electrode properties are determined using a physics-based electrochemical impedance spectroscopy (EIS) model that is fitted to three-electrode EIS measurements, with input from measured electrode capacity and scanning electrode microscopy (SEM). Results from the model fitting provide a detailed insight to the electrode degradation and is put into context with the behavior of the full cell aging. It was established that calendar aging has negligible effect on cell impedance, while cycle aging increases the impedance mainly due to structural changes in the LiFePO4 porous electrode and electrolyte decomposition products on both electrodes. Further, full-cell capacity fade is mainly a consequence of cyclable lithium loss caused by electrolyte decomposition.

  • 2377.
    Zeglinski, Jacek
    et al.
    Univ Limerick, Synth & Solid State Pharmaceut Ctr, Bernal Inst, Dept Chem Sci, Limerick V94 T9PX, Ireland..
    Kuhs, Manuel
    Univ Limerick, Synth & Solid State Pharmaceut Ctr, Bernal Inst, Dept Chem Sci, Limerick V94 T9PX, Ireland..
    Devi, K. Renuka
    Univ Limerick, Synth & Solid State Pharmaceut Ctr, Bernal Inst, Dept Chem Sci, Limerick V94 T9PX, Ireland..
    Khamar, Dikshitkumar
    Univ Limerick, Synth & Solid State Pharmaceut Ctr, Bernal Inst, Dept Chem Sci, Limerick V94 T9PX, Ireland..
    Hegarty, Avril C.
    Univ Limerick, Dept Math & Stat, MACSI, Limerick, Ireland..
    Thompson, Damien
    Univ Limerick, Synth & Solid State Pharmaceut Ctr, Bernal Inst, Dept Chem Sci, Limerick V94 T9PX, Ireland.;Univ Limerick, Dept Phys & Energy, Limerick, Ireland..
    Rasmuson, Åke C.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Transport Phenomena.
    Probing Crystal Nucleation of Fenoxycarb from Solution through the Effect of Solvent2019In: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 19, no 4, p. 2037-2049Article in journal (Refereed)
    Abstract [en]

    Induction time experiments, spectroscopic and calorimetric analysis, and molecular modeling were used to probe the influence of solvent on the crystal nucleation of fenoxycarb (FC), a medium-sized, flexible organic molecule. A total of 800 induction times covering a range of supersaturations and crystallization temperatures in four different solvents were measured to elucidate the relative ease of nucleation. To achieve similar induction times, the required thermodynamic driving force, RT In S, increases in the order: ethyl acetate < toluene < ethanol < isopropanol. This is roughly matched by the order of interfacial energies calculated using the classical nucleation theory. Solvent solute interaction strengths were estimated using three methods: solvent-solute enthalpies derived from calorimetric solution enthalpies, solvent-solute interactions from molecular dynamics simulations, and the FTIR shifts in the carbonyl stretching corresponding to the solvent solute interaction. The three methods gave an overall order of solvent solute interactions increasing in the order toluene < ethyl acetate < alcohols. Thus, with the exception of FC in toluene, it is found that the nucleation difficulty increases with stronger binding of the solvent to the solute.

  • 2378. Zevenhoven-Onderwater, Maria
    et al.
    Backman, Rainer
    Skrifvars, Bengt-Johan
    Hupa, Miko
    Liliendahl, Truls
    Rosén, Christer
    Sjöström, Krister
    Engvall, Klas
    KTH, Superseded Departments (pre-2005), Chemical Engineering and Technology.
    Hallgren, Anders
    KTH, Superseded Departments (pre-2005), Chemical Engineering and Technology.
    The ash chemistry in fluidised bed gasification of biomass fuels. Part I: Predicting the chemistry of melting ashes and ash-bed material interaction2001In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 80, no 10, p. 1489-1502Article in journal (Refereed)
    Abstract [en]

    This paper is part I in a series of two describing the modelling of the ash-chemistry of seven biomass fuels under reducing, pressurised conditions in fluidised bed gasification by means of thermodynamic multi-phase multi-component equilibrium (TPCE) calculations. The fuels considered were Salix, a Scandinavian forest residue, Miscanthus, Reed Canary Grass, Eucalyptus, Arundo Donax and Lucerne. The composition and amount of phases have been calculated for the gasification of the fuel as such and in presence of an excess amount of calcite, dolomite, magnesium olivine sand and sand by using TPCE calculations in a temperature interval of 600-900°C and a pressure of 10 bar. It was found that interaction of inorganic compounds released from the fuels with bed material is a prerequisite for the formation of bed agglomerates. The presence of an excess of dolomite decreased the amount of alkali components in the bed, thereby increasing the amount of alkali components volatilised. A silica bed, however, binds most alkali released from the fuel, retaining it in the bed as low melting alkali silicates. The chances of experiencing operating problems due to bed agglomeration may increase hereby significantly. Calculations at atmospheric pressure show that the amounts of melt present will be smaller when compared to pressurised conditions, thereby decreasing the chances of bed agglomeration. In a pressurised gasifier using calcite or dolomite as bed material a small amount of an alkali carbonate rich melt can be expected at temperatures above 620°C with each of the seven biomass fuels fired. In silica-rich cases such as when firing Miscanthus, Reed Canary Grass, Arundo Donax or using a Si-rich bed material a melt can be expected at temperatures above 770°C. The amount of melt is rather high, i.e. 12-100% of the original ash formed. In the case of a magnesium olivine sand bed an alkali melt can be expected at 620°C. At temperatures above 800°C, a silicate melt can form as well. The amount of melt was hi gh, i.e. 60-300% of the original ash formed, showing a significant contribution of the bed material.

  • 2379.
    Zhang, Chi
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Energy Processes.
    Sustainable Business Innovation of Photovoltaic Water Pumping Systems2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The development of renewable energy technology provides an effective approach to replace fossil fuels for greenhouse gas (GHG) emission. Technological innovation and transfer are the main driving forces in promoting renewable energy usage, because of the better efficiency and economic payback under an emission reduction target. With three of the mechanisms of emission trading originating from the Kyoto Protocol, the most wildly accepted and important mechanism between developed and developing countries is the Clean Development Mechanism (CDM). The CDM has been implemented contributing the most of the trading carbon credits. In this study, by extracting and building an exclusive database of issued Chinese CDM projects, a modified multivariable logistic regression model for technology transfer’s correlation test with 11 extended indicators was investigated for the first time. Renewable energy projects were analyzed with certified emission reduction (CER) sizes, economic development, and geographic scopes.In addition, technological innovation should also be enhanced with new business developments to demonstrate and scale up technologies for better economic and environmental performances. This doctoral thesis studied photovoltaic water pumping (PVWP) technology as a technological solution for integration with the new business model for development and co-benefits. The integration of PVWP with water saving irrigation techniques and sustainable management of water resources, leads to technical innovations, economic benefits, and climate benefits. Field measurements at a pilot PVWP system in Inner Mongolia were conducted with detailed economic performance analyses. Different scenarios for PVWP systems considering variant market incentives were proposed with internal rate of return (IRR), and discounted payback period analyses to develop a new business model approach for implementing PVWP systems with multi-value propositions. The environmental externalities were successfully addressed by evaluating the CO2 emission reduction credits. The economic assessment of feasible and optimal production processes for implementing PVWP systems in dairy milk production was conducted with self-supplied energy and forage assumptions. In comparison with other financing mechanisms, discrete choice model analyses were employed with interviews and costumer behavior surveys to explore the willingness to purchase through crowd funding mechanisms in financing integrated PVWP systems.The results showed that emission reduction mechanisms, such as CDM, have promoted the renewable energy development in China with the national incentives at an entrance level. Yet, the limited sizes and lower income from CERs of renewable energy projects than other projects, required renewable energy projects to develop more advanced technological innovations and business model innovations.  The PVWP systems represent the better technical and economic solutions under a feasible innovated business model in comparison with traditional photovoltaic (PV) systems and current PV business models. The dairy farms with integrated PVWP systems and self-sufficient feeds could improve their investment performance through extra energy saving and CO2 emission reductions. The semi-structured interviews and customer surveys’ results showed that customers can tolerate high prices, and are willing to crowd-fund nutritious and secure cow milk with environmental compensation characters. The results from the PVWP technology integration in China as a specific PV application study can be further applied for the business model of innovation of renewable energy systems in other regions of the world under emission reduction targets leading to economic and environmental benefits.

  • 2380.
    Zhang, Fan
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Brinck, Tore
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Brandner, Birgit
    Claesson, Per M.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Dédinaité, Andra
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Pan, Jinshan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    In situ confocal Raman micro-spectroscopy and electrochemical studies of mussel adhesive protein and ceria composite film on carbon steel in salt solutions2013In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 107, p. 276-291Article in journal (Refereed)
    Abstract [en]

    Thin films composed of Mefp-1 and ceria nanoparticles have shown an increasing corrosion inhibition effect with time for carbon steel in acidic aqueous solutions containing phosphate, which motivates a detailed study of the inhibition mechanism by in situ confocal Raman micro-spectroscopy (CRM) and electrochemical impedance spectroscopy (EIS) measurements. The presence of both CeO2 and ferric oxides in the thin composite film was demonstrated by X-ray photoelectron spectroscopy analysis. The Raman spectra assisted by DFT calculations suggest that Mefp-1 forms tri-Fe3+/Mefp-1 complexes and binds to ceria nanoparticles in the composite film. The in situ CRM measurement allow us to follow the development of corrosion products. The measurements show a mixture of Fe oxides/oxyhydroxides, and also indicate that ferrous oxides may be further oxidized by the composite film. Moreover, phosphate ions react with the Fe ions released from the surface to form iron-phosphate deposits, which become incorporated into the corrosion product layer and the composite film. The EIS measurements suggest a layered surface structure formed by the initial Mefp-1/ceria composite layer and the corrosion products/iron-phosphate deposits. These measurements also demonstrate the greatly increased inhibition effect of the composite film in the presence of the phosphate ions. The consistent CRM and EIS results suggest that the iron-phosphate deposits heal defects in the composite film and corrosion product layer, which results in a significantly improved corrosion inhibition of the Mefp-1/ceria composite film during initial and long term exposure.

  • 2381.
    Zhang, Fan
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Chen, Chengdong
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Hou, R.
    Li, Jing
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Cao, Yanhui
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Dong, S.
    Lin, C.
    Pan, Jinshan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Investigation and application of mussel adhesive protein nanocomposite film-forming inhibitor for reinforced concrete engineering2019In: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 153, p. 333-340Article in journal (Refereed)
    Abstract [en]

    A mussel adhesive protein based nanocomposite thin film was produced to be applied as surface pre-treatment or primer on rebars of reinforced concrete. The film deposition and drying processes were investigated to enhance the corrosion protection, and facilitate large-scale industrial applications. The morphology, chemical composition and microstructure of the film were characterised with SEM, EDS, Micro-IR and AFM techniques. EIS results suggested the film provides excellent and increased corrosion protection for the carbon steel in mild and extreme concrete pore solutions. In-situ AFM results demonstrated the self-healing ability of the film to the pitting corrosion.

  • 2382.
    Zhang, Fan
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Pan, Jinshan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Claesson, Per Martin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Brinck, Tore
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Electrochemical, atomic force microscopy and infrared reflection absorption spectroscopy studies of pre-formed mussel adhesive protein films on carbon steel for corrosion protection2012In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 520, no 24, p. 7136-7143Article in journal (Refereed)
    Abstract [en]

    Electrochemical measurements, in situ and ex situ atomic force microscopy (AFM) experiments and infrared reflection absorption spectroscopy (IRAS) analysis were performed to investigate the formation and stability as well as corrosion protection properties of mussel adhesive protein (Mefp-1) films on carbon steel, and the influence of cross-linking by NaIO 4 oxidation. The in situ AFM measurements show flake-like adsorbed protein aggregates in the film formed at pH 9. The ex situ AFM images indicate multilayer-like films and that the film becomes more compact and stable in NaCl solution after the cross-linking. The IRAS results reveal the absorption bands of Mefp-1 on carbon steel before and after NaIO 4 induced oxidation of the pre-adsorbed protein. Within a short exposure time, a certain corrosion protection effect was noted for the pre-formed Mefp-1 film in 0.1 M NaCl solution. Cross-linking the pre-adsorbed film by NaIO 4 oxidation significantly enhanced the protection efficiency by up to 80%.

  • 2383. Zhang, Guoqiang
    et al.
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Jin, Hongguang
    Dahlquist, Erik
    Integrated Black Liquor Gasification Polygeneration System with CO2 Capture in Pulp and Paper Mills to Produce Methanol and Electricity2011In: International Journal of Green Energy, ISSN 1543-5075, E-ISSN 1543-5083, Vol. 8, no 2, p. 275-293Article in journal (Refereed)
    Abstract [en]

    Based on KAMa pulp and paper mill, a polygeneration system integrated with a black liquor gasifier is proposed. The effects of CO2 captured by oxygen-fuel combustion and Selexol absorption on the performance of the polygeneration system are studied in terms of both thermodynamic performance and cost assessment. Using the Aspen Plus simulator, the performance of the studied polygeneration systems are analyzed from the perspectives of the first and second laws of thermodynamics. Compared with the reference system, the first law efficiency of the polygeneration system increased from 15.7% to 29.3%, with an investment increment of 17.9%. The investment incremental rates for CO2 capture by oxyfuel combustion and Selexol absorption are 15.1% and 16.7%, respectively. Energy penalty due to CO2 capture and compression is 0.61 MJ electricity/kg CO2, avoided in the oxygen-fuel method at a cost of $29.6/tonne CO2. However, energy penalty can reach 1.03 MJ product (electricity and methanol) per kg CO2, avoided in the Selexol absorption CO2 capture process at a cost of $46.0/tonne CO2.

  • 2384. Zhang, Junqiao
    et al.
    Li, Debing
    Sun, Tianyang
    Liang, Lijun
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology. Zhejiang University, China.
    Wang, Qi
    Interaction of P-glycoprotein with anti-tumor drugs: the site, gate and pathway2015In: Soft Matter, ISSN 1744-683X, E-ISSN 1744-6848, Vol. 11, no 33, p. 6633-6641Article in journal (Refereed)
    Abstract [en]

    Understanding the mechanism and pathway of anti-cancer drugs to be pumped out by P-glycoprotein (P-gp) in cancer cell is very important for the successful chemotherapy. P-gp is a member of ATP-binding cassette (ABC) transporters. In this study, random accelerated molecular dynamics (RAMD) simulation was used to explore the potential egress pathway of ligands from the binding pocket. This could be considered as a reverse process of drug binding. The most possible portal of drugs to dissociate is TM4/TM6, which is almost the same for different drugs, such as paclitaxel and doxorubicin. The interactions in the binding site are found to be remarkably stronger than that outside of the binding site. The results were suggested by the free energy calculation between P-gp and different drugs from metadynamics simulation. All the results indicate that the flexibility of inner residues, especially the residue Phe339, is very important for the drugs to access the binding site.

  • 2385.
    Zhang, Le
    KTH, School of Chemical Science and Engineering (CHE).
    Large Scale Production of Polylactide Microspheres for Controlled Drug Delivery2012Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Spray drying is presented as an efficient technique to manufacture spherical polylactide particles in large scale for use in controlled drug delivery applications. Poly (L-lactide) (PLLA) was synthesized by ring-opening polymerization and PLLA microspheres were produced by spray drying. The PLLA microspheres were morphologically characterized by SEM and the release profile of drug loaded in the microspheres were analyzed by UV-VIS. The morphology of PLLA microspheres was significantly influenced by solvent, molecular weight, and the operating settings of the instrument.

    PLLA particles loaded with diclofenac sodium and caffeine were produced using the 10,000 and 20,000 g/mol molecular weight PLLAs and the previously determined operating conditions. The morphologies of particles loaded with drug were influenced by solvent type. The drug encapsulation efficiency of caffeine was much higher than that of diclofenac sodium.

    The release rate was affected by the type of drug loaded and the particle morphology. Particles of small size released drug faster because of larger surface area and particles with a rough surface and high porosity also demonstrated an increased drug release rate. All loaded diclofenac sodium was released from the particles after 400 hours whereas only 30-50% of the loaded caffeine was released during the same time period.

  • 2386.
    Zhang, Liming
    et al.
    KTH, Superseded Departments, Fibre and Polymer Technology.
    Gellerstedt, Göran
    KTH, Superseded Departments, Fibre and Polymer Technology.
    Qualitative and quantitative study of lignin structure by applying highresolution 2D HSQC NMR technique2004In: 2nd International Symposium on Technologies Of Pulping, Papermaking and Biotechnology on Fiber Plants, Proceedings / [ed] Jin, YC; Xie, HF, NANJING: NANJING FORESTRY UNIV , 2004, p. 88-92Conference paper (Refereed)
    Abstract [en]

    High-resolution 2D HSQC NMR technique was found to be a powerful analytical tool for studies on lignin structure. High resolution in the F1 dimension of an HSQC spectrum can be obtained by proper sample purification and optimized shimming as well as by acquiring large enough increments. By combining the results from 2D HSQC, HSQC-TOCSY and HMBC NMR experiments, novel lignin structures, including spiro-dienone, secoisolariciresinol and neo-olivil have been observed and identified. The concept of quantitative structure determination by applying 2D HSQC NMR technique was investigated. The influence of T-2 relaxation decays, coupling constant, off-resonance effect and homonuclear couplings on NMR signal quantification have been discussed. beta-5 Structure in a lignin sample was accurately determined by using the HSQC NMR analysis through a unique way of selecting the proper internal standard reference signal(s).

  • 2387. Zhang, M.
    et al.
    Wang, R.
    Xiang, T.
    Zhao, Wei-Feng
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology. Sichuan University, China.
    Zhao, C. -S
    Preparation, characterization and application of poly(sodium p-styrenesulfonate)/poly(methyl methacrylate) particles2016In: Journal of Industrial and Engineering Chemistry, ISSN 1226-086X, E-ISSN 1876-794X, Vol. 34, p. 415-421Article in journal (Refereed)
    Abstract [en]

    In this study, poly(sodium p-styrenesulfonate)/poly(methyl methacrylate) particles were facilely prepared by in situ cross-linked polymerization followed with a liquid-liquid phase inversion technique. The particles exhibited selective adsorption for cationic dyes due to the negatively charged sulfonic groups. The intra-particle diffusion process was the rate-limiting step for the adsorption of methylene blue. More than 90% of cationic dye was removed by the adsorption column of the particles after three circulations. The particles could be facilely fabricated and industrially used for wastewater treatment.

  • 2388. Zhang, Man
    et al.
    Wang, Rui
    Shi, Zhenqiang
    Huang, Xuelian
    Zhao, Weifeng
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Zhao, Changsheng
    Multi-responsive, tough and reversible hydrogels with tunable swelling property2017In: Journal of Hazardous Materials, ISSN 0304-3894, E-ISSN 1873-3336, Vol. 322, p. 499-507Article in journal (Refereed)
    Abstract [en]

    A novel family of multi-responsive, tough, and reversible hydrogels were prepared by the combination of dipole-dipole interaction, hydrogen bonding interaction and slightly chemical cross-linking, using monomers of acrylonitrile, sodium allylsulfonate and itaconic acid. Reversible gel-sol transition was achieved by the flexible conversion of the dipole-dipole interactions between acrylonitrile-acrylonitrile and acrylonitrile-sodium thiocyanate, and the hydrogels could freely form desired shapes. The dipole dipole and hydrogen bonding interactions improved the mechanical strength of the hydrogels with a compressive stress of 2.38 MPa. Meanwhile, the hydrogels sustained cyclic compressive tests with 60% strain, and exhibited excellent elastic property. The hydrogels were sensitive to pH and ionic strength, and could keep their perfect spherical structures without any obvious cracks even after immersing in strong ionic strength (or pH) solution for several reversible cycles. Furthermore, the hydrogels were recycled for environmental pollution remediation, and showed great potential to be applied in water treatments and other related fields.

  • 2389.
    Zhang, Qinglin
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Dor, Liran
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Blasiak, Wlodzimierz
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Eulerian Model for Municipal Solid Waste Gasification in a Fixed-Bed Plasma Gasification Melting Reactor2011In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 25, no 9, p. 4129-4137Article in journal (Refereed)
    Abstract [en]

    Plasma gasification melting (PGM) is a promising waste-to-energy process, which provides many features superior to those of conventional gasification. In this work, a steady Euler Euler multiphase model is developed to predict the performance of municipal solid waste (MSW) gasification inside a PGM reactor. The model considers the main chemical and physical processes, such as drying, pyrolysis, homogeneous reactions, heterogeneous char reactions, and melting of the inorganic components of MSW. The model is validated by one experimental test of a pilot reactor. The characteristics of PGM gasification, such as temperature distribution, syngas composition, tar yield, and energy conversion ratio (ECR, chemical energy of the gas phase divided by the total energy input), at the proposed condition are discussed. A total of nine cases are used to investigate the effects of the equivalence ratio (ER) and plasma power with a fixed flow rate of MSW. It is found that the ER has a positive effect on the cold gas efficiency of PGM gasification. However, the increase of the ER is restricted by the peak temperature. The influence of the plasma power then is not obvious for PGM gasification.

  • 2390.
    Zhang, Shuo
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Physical properties and crystallization of theophylline co-crystals2010Licentiate thesis, monograph (Other academic)
    Abstract [en]

    This work focuses on the physical properties and crystallization of theophyline co-crystals. Co-crystals of theophylline with oxalic acid, glutaric acid and maleic acid have been investigated.

    The DSC curves of these co-crystals show that their first endothermic peaks are all lower than the melting temperature of theophylline. The decomposition temperature of theophylline – oxalic acid co-crystal is at about 230 °C, determined by DSC together with TGA. After decomposition, the remaining theophylline melts at about 279 °C, which is higher than the known melting temperature of theophylline, suggesting a structure difference, ie. a new polymorph may have been formed. The formation of hydrogen bonds in theophylline – oxalic acid co-crystal was investigated by FTIR. Changes of FTIR peaks around 3120 cm-1 reflects the hydrogen bond of basic N of theophylline and hydroxyl H of oxalic acid. The solubility of theophylline – oxalic acid co-crystal and theophylline – glutaric acid co-crystal was determined in 4:1 chlroform – methanol and in pure chloroform respectively. At equilibrium with the solid theophylline – oxalic acid co-crystal, the theophylline concentration is only 60 % of the corresponding value for the pure solid theophylline. At equilibrium with the solid theophylline – glutaric acid co-crystal, the theophylline concentration is at least 5 times higher than the corresponding value for the pure solid theophylline. Two phases of theophylline were found during the solubility determination. In the chloroform – methanol mixture (4:1 in volume ratio) the solubility of the stable polymorph of theophylline is found to be about 14 % lower than that of the metastable phase. Various aspects of the phase diagram of theophylline – oxalic acid co-crystal was explored.

    Theophylline – oxalic acid co-crystal has been successfully prepared via primary nucleation from a stoichiometric solution mixture of the two components in chloroform – methanol mixture. By slurry conversion crystallization, the co-crystal can be prepared in several solvents, and yield and productivity can be significantly increased. Theophylline – glutaric acid can be successfully prepared via both co-grinding of the two components and slow evaporation with seeding.

  • 2391.
    Zhang, Shuo
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Rasmuson, Ake C.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    The theophylline-oxalic acid co-crystal system: solid phases, thermodynamics and crystallisation2012In: CrystEngComm, ISSN 1466-8033, E-ISSN 1466-8033, Vol. 14, no 14, p. 4644-4655Article in journal (Refereed)
    Abstract [en]

    The solid phases in the theophylline-oxalic acid co-crystal system have been investigated by thermal analysis techniques, X-ray diffraction analysis (XRD) and solubility measurements. The work includes the 2 : 1 co-crystal of theophylline and oxalic acid, polymorphs of theophylline, the theophylline monohydrate and solid oxalic acid. The DSC curve of the co-crystal presents two endothermic peaks, one at about 230 degrees C where the oxalic acid in the co-crystal decomposes and carbon dioxide is liberated, and another one at 279 degrees C where the remaining theophylline melts. At equilibrium with the solid co-crystal, the theophylline concentration is only 60% of the corresponding value for the pure solid theophylline. Using the solubility data, the standard Gibbs free energy of formation of the co-crystal from the pure solid phases is estimated to be approximately -6.0 kJ mole(-1). In a chloroform/methanol mixture (4 : 1 v : v) the commercial form of pure theophylline (Form II) has been observed to transform into a more stable non-solvated form (Form I). The data suggest that the polymorphs are enantiotropically related with an approximate transition temperature of 70 degrees C. The 2 : 1 theophylline-oxalic acid co-crystal can be successfully produced by cooling crystallisation in chloroform/methanol mixture (4 : 1 v : v) and by slurry conversion crystallisation also in more benign solvents.

  • 2392.
    Zhang, Shuo
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Rasmuson, Åke C.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Thermodynamics and Crystallization of the Theophylline-Glutaric Acid Cocrystal2013In: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 13, no 3, p. 1153-1161Article in journal (Refereed)
    Abstract [en]

    This work investigates the thermodynamics and crystallization of the theophylline glutaric acid 1:1 cocrystal. It is found that the cocrystal physically decomposes at 120 degrees C (i.e., in the range between the melting points of the two pure compounds). The solubility of the cocrystal and pure compounds has been determined in chloroform and acetonitrile. In chloroform, the theophylline concentration of the saturated solution over the cocrystal is clearly higher than that in the saturated solution over pure theophylline I/II, while for glutaric acid the situation is the opposite. With the solubility data, the Gibbs free energy of the formation of the cocrystal from solid theophylline II and solid beta-glutaric acid at 30 degrees C can be estimated to -0.39 kJ mol(-1). The work reveals that polymorphism in the pure components of a cocrystal can dramatically influence the phase diagram and shift an incongruently dissolving case into a kinetically stabilized congruent case. In chloroform, the cocrystal dissolves incongruently with respect to the stable form I of theophylline but congruently with respect to the metastable theophylline II. However, the cocrystal is stable in a stoichiometric solution for more than 2 weeks. Given sufficient time, the system should transform into a solid phase being a mixture of cocrystal and stable theophylline I, in equilibrium with a solution that has the composition of the corresponding invariant point. In acetonitrile, where the glutaric acid solubility is much higher than that of theophylline II, the cocrystal dissolves, clearly incongruently. The region where the cocrystal is the only solid stable phase is clearly shifted toward the glutaric acid side and is fairly narrow. In both solvents the cocrystal can readily be produced by isothermal slurry conversion crystallization to a reasonable level of productivity, as long as the process is operated in a region of the phase diagram where the cocrystal is the only stable (or reasonably metastable) solid phase.

  • 2393.
    Zhang, Xian
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Liu, Xiaoyan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Odnevall Wallinder, Inger
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    The protective role of hydrozincite during initial corrosion of a Cu40Zn alloy in chloride-containing laboratory atmosphere2016In: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 103, p. 20-29Article in journal (Refereed)
    Abstract [en]

    Hydrozincite, Zn-5(CO3)(2)(OH)(6), was recently found to play a key role in reducing corrosion product flaking on Cu-Zn alloys. A fundamental study was undertaken to explore the underlying mechanisms, in particular why hydrozincite can suppress the interaction between chlorides and the alloy surface. Hydrozincite could be formed by exposure of Cu40Zn to air at 70% relative humidity and 1000 ppm of CO2 resulting in a surface of decreased wettability. Its presence reduces the initial spreading ability of NaCl-containing droplets and lowers the overall initial corrosion rate when the alloy is exposed to pre-deposited NaCl and wet/dry cycles.

  • 2394.
    Zhang, Xian
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. Wuhan Univ Sci & Technol, State Key Lab Refractory Mat & Met, Hubei Prov Key Lab Syst Sci Met Proc, Int Res Inst Steel Technol, Wuhan 430081, Hubei, Peoples R China..
    Odnevall Wallinder, Inger
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Leygraf, Christopher
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Atmospheric corrosion of Zn-Al coatings in a simulated automotive environment2018In: Surface Engineering, ISSN 0267-0844, E-ISSN 1743-2944, Vol. 34, no 9, p. 641-648Article in journal (Refereed)
    Abstract [en]

    Accelerated NVDA (VDA 233-102) tests were performed on bare Zn and Al sheets, Galfan coating (Zn-5 wt-% Al) and Galvalume coating (Zn-55 wt-% Al) on steel. ZnO, Zn(OH)(2) and Zn-5(OH)(8)Cl-2 center dot H2O were the main corrosion products identified on both bare Zn sheet and Galfan. AlOOH and Al(OH)(3) were preferentially formed on bare Al sheet and Galvalume. In addition, Zn-Al-containing corrosion products, Zn6Al2(OH)(16)CO3 center dot 4H(2)O and/or Zn2Al(OH)(6)Cl center dot 2H(2)O were identified on both Galfan and Galvalume. Corrosion products of Zn6Al2(OH)(16)CO3 center dot 4H(2)O with a platelet morphology were preferentially formed in the zinc-rich interdendritic regions of the Galvalume surface. Galfan revealed a similar corrosion behaviour as bare Zn sheet, whereas Galvalume exhibited similar behaviour as bare Al sheet. Deposition of chlorides highly influenced the corrosion of both Galvalume and Al rather than Galfan and Zn due to the rapid local damage of the compact native thin film of Al2O3.

  • 2395.
    Zhang, Yang
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Integration of Battery and Hydrogen Storage with a Grid-Connected Photovoltaic System in Buildings2017Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

        The integration of Photovoltaic (PV) with buildings changes the previous electricity consumers into prosumers. The reduced PV subsidies and the grid stable operation requirements are pushing prosumers from direct exportation to self-consumption of the produced electricity. Electricity storage increases the self-consumption, while comes with higher investment. During the system planning stage, the benefits of storage should be clarified to prosumers. The storage type, the storage capacity and the system operation strategy should be determined at the same time.

        This thesis dealt with a grid-connected PV-storage system and proposed an optimization method, which simultaneously determined the storage capacity and rule-based operation strategy parameters. This method eliminated the necessity of forecasting and could be easily implemented. A typical residential building in Sweden was taken as a case study. Different operation strategies as well as two storage technologies – battery storage and hydrogen storage – were compared.

        For the battery storage system, the proposed battery hybrid operation strategy, which carries out the conventional operation strategy during warm months and the peak shaving strategy during cold months, provides the best performance in Self Sufficiency Ratio (SSR) and Net Present Value (NPV). For the hydrogen storage system, the hydrogen hybrid operation strategy outperforms other studied operation strategies under different scenarios, which have optimistic or pessimistic cost assumptions of the hydrogen storage system.

        The comparison between hydrogen storage and battery storage suggests that battery storage has much better performance in SSR and NPV under the pessimistic cost scenario. Under the optimistic cost scenario, battery storage and hydrogen storage achieve comparable performance in SSR and NPV. However, hydrogen storage is more favorable when considering reducing the prosumer’s negative impact on the grid.

  • 2396.
    Zhang, Yang
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Energy Processes.
    Integration of Distributed Renewable Energy and Energy Storages in Buildings2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Photovoltaic (PV) is a distributed renewable energy technology that is suitable for integration in buildings. PV reduces the electricity demands as well as the greenhouse gas emissions of buildings. However, the surplus electricity from PV is exported to the electricity grid, which not only lowers the economic performance of the PV but also creates operational problems in the grid. Efficient approaches should be identified to improve PV’s economic and environmental performance.

    Buildings differ by their connections to energy networks. In buildings that are only connected to the electricity grid, electrical energy storages— including battery and hydrogen storage—can mitigate the mismatch between production and consumption. When a grid-connected PV system follows the conventional operation strategy, its economic performance worsens with storage. Two new operation strategies are developed. With a developed optimization framework, operation strategies and storage capacities are optimized simultaneously. Optimization results indicate that both net present value and self-sufficiency ratio are increased by storages. A comparison between battery storages and hydrogen storages shows that the hydrogen storage can compete with the battery counterpart under an optimistic hydrogen storage cost scenario. In addition, the hydrogen storage can better decrease the exported electricity.

    In buildings that are connected to the electricity grid and the district heating network, additional energy conversion and storage equipment— including heat pumps, electrical heaters, and hot water tanks—can be installed to form an integrated energy system (IES). After optimal system sizing, the IES decreases the net present cost by 22%, and the self-consumption ratio increases from 43% to 61%. Moreover, the IES serves as a new flexibility measure, and the provided flexibility energy is over 36% of its electricity consumption. During system planning, the system configuration and operation cost are obtained without considering forecast errors. Through the year-round simulation of system operation that considers forecast errors, a corrected operation cost is obtained. The yearly operation cost difference between system operation and system planning is less than 4% and 6% under the high and low forecast accuracy scenarios.

    The full text will be freely available from 2019-12-31 12:46
  • 2397. Zhao, L.
    et al.
    Yang, X.
    Deng, S.
    Li, Hailong
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Yu, Z.
    Performance analysis of the ejector-expansion refrigeration cycle using zeotropic mixtures2015In: International journal of refrigeration, ISSN 0140-7007, E-ISSN 1879-2081, Vol. 57, p. 197-207, article id 3043Article in journal (Refereed)
    Abstract [en]

    Abstract To evaluate the performance of the ejector-expansion refrigeration cycle (EERC) using zeotropic mixtures, a numerical study is conducted. A constant-pressure two-phase ejector model for zeotropic mixtures is established. The effects of both the fluid composition and the working conditions are investigated. Mixture R134a/R143a is selected as the working and the simulation results reveal that, the cycle COP increases first and then decreases as MF<inf>t</inf> (the mass fraction of R134a) increases in the researched condition. The COP gets a maximum value of 4.18 with MF<inf>t</inf> of 0.9 and yields a minimum value of 3.66 with MF<inf>t</inf> of 0.5. With mixture 0.9/0.1, the COP improvement reaches a maximum value of 10.47%. This improvement rises at high condensing temperature or low evaporating temperature. The exergy analysis shows that the compressor and ejector contribute the most exergy destruction, and the cycle exergy efficiency achieves a maximum value with MF<inf>t</inf> of 0.7.

  • 2398. Zhao, Ruikai
    et al.
    Deng, Shuai
    Zhao, Li
    Liu, Yinan
    Tan, Yuting
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Energy-saving pathway exploration of CCS integrated with solar energy: Literature research and comparative analysis2015In: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 102, p. 66-80Article in journal (Refereed)
    Abstract [en]

    One of main technical barriers to a large-scale application of carbon capture and storage (CCS) technology is a significant amount of required energy, e.g., regeneration heat of solvent in the chemical absorption system. Thus, energy consumption and corresponding high operation cost become two primary challenges for the promotion of CCS technology. Meanwhile, energy from the solar source in various forms has already been successfully used as an effective alternative supply in the industrial section for drying, heating and even cooling. Thus, integrating solar energy utilization into the CCS process could be a reasonable option for a sustainable development. A comparative analysis of CCS integrated with solar energy was presented in this paper based on the existing researches. The current status on typical configuration structure, feature and energy-efficiency performance of integrating options is reviewed for post-combustion, pre-combustion and oxygen-combustion systems. Based on these typical CO2 capture systems, a theoretical analysis is conducted for an energy-efficient comparison. Then four typical structures of the post-combustion system, which are highlighted in the review, are chosen as comparative objects for energy-saving and techno-economic evaluation. The results show that systems with a solar-assisted thermal energy and power generation have comparative advantages in term of carbon emission intensity, but the economic cost is increased under the current conditions of the equipment price. Compared to that of baseline case, carbon emission intensity of the case integrated with solar Organic Rankine Cycle can be reduced with a maximum decline of 9.73%, meanwhile the levelized costs of electricity increases 0.01 USD/kW h correspondingly.

  • 2399.
    Zhao, Weifeng
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology. Sichuan Univ, Peoples R China.
    Huang, Xuelian
    Wang, Yilin
    Sun, Shudong
    Zhao, Changsheng
    A recyclable and regenerable magnetic chitosan absorbent for dye uptake2016In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 150, p. 201-208Article in journal (Refereed)
    Abstract [en]

    A recyclable and regenerable magnetic polysaccharide absorbent for methylene blue (MB) removal was prepared by coating magnetic polyethyleneimine nanoparticles (PEI@MNPs) with sulfonated chitosan (SCS) and further cross -linked with glutaraldehyde. The driving force for coating is the electrostactic interaction between positively charged PEI and negatively charged SCS. Infrared spectra, zeta potential, thermal gravimetric analysis and X-ray diffraction demonstrated the successful synthesis of magnetic polysaccharide absorbent. The self-assembly of polysaccharide with magnetic nanopartices did not alter the saturation magnetization value of the absorbent confirmed by vibrating sample magnetometer. The nanoparticles showed fast removal (about 30 min reached equilibrium) of MB. In particular, the removal ability of MB after desorption did not reduce, demonstrating an excellent regeneration ability. Our study provides new insights into utilizing polysaccharides for environmental remediation and creating advanced magnetic materials for various promising applications.

  • 2400.
    Zhao, Weifeng
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology. Sichuan University, China.
    Nugroho, Robertus Wahyu. N.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Odelius, Karin
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Edlund, Ulrica
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Zhao, Changsheng
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    In Situ Cross-Linking of Stimuli-Responsive Hemicellulose Microgels during Spray Drying2015In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 7, no 7, p. 4202-4215Article in journal (Refereed)
    Abstract [en]

    Chemical cross-linking during spray drying offers the potential for green fabrication of microgels with a rapid stimuli response and good blood compatibility and provides a platform for stimuli-responsive hemicellulose microgels (SRHMGs). The cross-linking reaction occurs rapidly in situ at elevated temperature during spray drying, enabling the production of microgels in a large scale within a few minutes. The SRHMGs with an average size range of similar to 1-4 mu m contain O-acetyl-galactoglucomannan as a matrix and poly(acrylic acid), aniline pentamer (AP), and iron as functional additives, which are responsive to external changes in pH, electrochemical stimuli, magnetic field, or dual-stimuli. The surface morphologies, chemical compositions, charge, pH, and mechanical properties of these smart microgels were evaluated using scanning electron microscopy, IR, zeta potential measurements, pH evaluation, and quantitative nanomechanical mapping, respectively. Different oxidation states were observed when AP was introduced, as confirmed by UV spectroscopy and cyclic voltammetry. Systematic blood compatibility evaluations revealed that the SRHMGs have good blood compatibility. This bottom-up strategy to synthesize SRHMGs enables a new route to the production of smart microgels for biomedical applications.

454647484950 2351 - 2400 of 2452
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