17 results on '"Kim Dam-Johansen"'
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2. Silica aerogel-encapsulated biocide crystals for low-loading antifouling coatings: rheology, water absorption, hardness, and biofouling protection
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Tenna Frydenberg, Claus Erik Weinell, Kim Dam-Johansen, Eva Wallström, and Søren Kiil
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Colloid and Surface Chemistry ,Surfaces and Interfaces ,General Chemistry ,Surfaces, Coatings and Films - Published
- 2022
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3. Intumescent alkali silicate and geopolymer coatings against hydrocarbon fires
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Burak Ulusoy, Aixiao Fu, Hafeez Ahmadi, Kim Dam-Johansen, and Hao Wu
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Colloid and Surface Chemistry ,Surfaces and Interfaces ,General Chemistry ,Surfaces, Coatings and Films - Published
- 2022
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4. Marine biofouling resistance rating using image analysis
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Claus Erik Weinell, Morten Lysdahlgaard Pedersen, Kim Dam-Johansen, and Burak Ulusoy
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Colloid and Surface Chemistry ,Biofouling ,Biofouling recognition ,Ilastik ,SDG 14 - Life Below Water ,Surfaces and Interfaces ,General Chemistry ,Fouling control coatings ,Image analysis ,Surfaces, Coatings and Films - Abstract
Biofouling on ship hulls can cause increased fuel consumption and the global spread of nonindigenous species. The shipping industry utilizes fouling control coatings (FCC) to prevent biofouling from occurring on the ship hull. The evaluation standards for the performance of FCC are based on manual inspections, which unavoidably induce some degree of subjectivity. A standardized biofouling recognition model using image analysis would provide a more objective basis for the evaluation of FCC. For this purpose, several coated panels were immersed in the ocean at CoaST Maritime Test Centre for an exposure period of six weeks, whereafter, the panels were fully covered with biofouling. The program ilastik was then successfully used to train a pixel classification model, which could provide a simple segmentation of the different biofouling categories detected on a coated surface. From the simple segmentation, a coverage percentage of biofouling was determined. The percentages can stand alone to provide information on the degree of biofouling or be used in combination with the guidelines from the European Chemicals Agency to calculate a fouling resistance rating (FRR). The FRR obtained from the model was compared with FRR values obtained from the manual evaluation of the panels.
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- 2022
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5. A char stratification approach to characterization and quantitative thermal insulation performance of hydrocarbon intumescent coatings
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Ying Zeng, Claus Erik Weinell, Kim Dam-Johansen, Louise Ring, and Søren Kiil
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Colloid and Surface Chemistry ,Surfaces and Interfaces ,General Chemistry ,Surfaces, Coatings and Films - Abstract
To protect structural steel in the event of a hydrocarbon fire, epoxy-based intumescent coatings, which expand to form a multicellular char layer, are increasingly used. Consequently, to improve formulations and understand the performance of such coatings, it is of great industrial and scientific interest to establish relationships between the char properties and the critical heating times of coated steel plates. In this work, a so-called Stratification Parameter (SP) that combines the relative expansions and insulation efficiencies of individual char layers (termed the sponge-like, the macroporous, and the compact phase, respectively), is introduced to characterize the properties of the multilayered intumescent coating char. An approximate linear relationship was revealed between the SP of the char and the fire-resistance performance (i.e. critical times to 400 and 550 oC) of the intumescent coating. Furthermore, owing to the mapped-out exponential relationship between the dynamic viscosity minimum and the char appearance, it was discovered that the SP of the char can be effectively used to point out the required dynamic viscosity change of an intumescent coating to form a given char. Finally, results of thermogravimetric analyses suggest that constraining the coating mass loss during char degradation (to less than 28 wt.% for the coatings of the present work) may prevent the formation of the less efficient sponge-like phase. The stratification methodology developed, can be used to estimate expected thermal insulation properties of non-uniform hydrocarbon intumescent coating chars
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- 2022
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6. Wet clay adhesion to antistick coatings: effects of binder type and surface roughness
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Svava Davidsdottir, Kim Dam-Johansen, Josep Palasi, Andrea Fasano, Søren Kiil, Claus Erik Weinell, Liliana Madaleno, and Lars Skaarup Jensen
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Materials science ,Process equipment ,Friction measurements ,02 engineering and technology ,engineering.material ,Raw material ,010402 general chemistry ,01 natural sciences ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,Silicone ,Coating ,Surface roughness ,Composite material ,Cement industry ,Polyurethane ,Cement ,Antistick coatings ,Surfaces and Interfaces ,General Chemistry ,Adhesion ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Surfaces, Coatings and Films ,chemistry ,Steel ,Wet clay ,engineering ,0210 nano-technology - Abstract
The handling of sticky raw material can cause problems during operation of process equipment in the cement production industry. These handling problems are generally observed when raw material (e.g. wet clay) sticks to machine walls and causes blockage of outlets. This leads to frequent production shutdowns and expensive cleaning operations. In this work, the effects of surface material and process parameters on the friction forces between wet clay and surface were investigated. Various surface materials and clay impact speeds were investigated.The results demonstrate that not only the equipment surface material but also the surface roughness influences the observed frictional behavior. The ranking of the materials in terms of effective static friction coefficients fell in two groups with equal performance within the group: 1) Two Teflon-based coatings (Accofal 2G54 and Accolan LB), polished AISI 304 stainless steel, Matrox lining, and a polyurethane-based coating (best performing surfaces), 2) Mild steel, a silicone-based coating, and AISI 304 stainless steel (worst performing surfaces). However, the friction coefficients of the two groups only varied by a factor of two, suggesting that adhesion of wet clay to surfaces is difficult to avoid by the use of coatings.
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- 2019
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7. Electron microscope investigations of activated chalcopyrite particles via the FLSmidth® ROL process
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Anne Juul Damø, Adam Paul Karcz, Sara Rocks, Chaiko David J, Kim Dam-Johansen, and Jytte Boll Illerup
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Materials science ,Passivation ,Chalcopyrite ,Mechanical Engineering ,Kinetics ,Inorganic chemistry ,chemistry.chemical_element ,02 engineering and technology ,Crystal structure ,021001 nanoscience & nanotechnology ,Copper ,020501 mining & metallurgy ,0205 materials engineering ,chemistry ,Mechanics of Materials ,visual_art ,visual_art.visual_art_medium ,General Materials Science ,Reactivity (chemistry) ,Leaching (metallurgy) ,0210 nano-technology ,Dissolution - Abstract
Because of its unique semiconductor properties, the world’s most abundant copper mineral, chalcopyrite (CuFeS2), is refractory with respect to atmospheric leaching using traditional acidic ferric sulfate lixiviants. FLSmidth® has developed a novel approach manipulating lattice properties of semi-conducting minerals with the benefit of increasing chemical reactivity and dissolution kinetics. In the FLSmidth® Rapid Oxidative Leach (ROL) process, leach kinetics are still further enhanced by combining chemical and mechanical processes with the assistance of a Stirred Media Reactor. Due to the reduction in surface passivation problems associated with atmospheric leaching, this process is typically able to achieve copper recoveries exceeding 95% in 6 h. An important factor contributing to this extraordinary process performance is a mineral preconditioning step (the focus of this study), which uses between 0.1 and 5 mol percent of copper (II) to dope the lattice and thereby “activate” chalcopyrite. Since lattice restructuring can have such a dramatic influence on semiconductor reactivity, the associated physico-chemical phenomena are worth studying. In this regard, we investigate the relationship between chemical activation and deformation of the chalcopyrite crystal lattice through the use of electron microscopy. Although the activation process took only an hour and the extent of conversion was on the order of a few mol%, the lattice was found to be strained throughout the particle. This paper draws some insights into the impact of applying chemical activation as a pretreatment for mechanochemical processes.
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- 2017
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8. Acid-resistant organic coatings for the chemical industry: a review
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Sarah Maria Grundahl Frankær, Kim Dam-Johansen, Søren Kiil, and Victor Buhl Møller
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Fiber reinforcement ,Chemical substance ,Materials science ,Abrasion (mechanical) ,Acid resistance ,02 engineering and technology ,Protective coating ,010402 general chemistry ,01 natural sciences ,Corrosion ,Colloid and Surface Chemistry ,Coating degradation ,Application areas ,Coating analysis ,business.industry ,Metallurgy ,Surfaces and Interfaces ,General Chemistry ,Chemical industry ,021001 nanoscience & nanotechnology ,Pulp and paper industry ,Degradation mechanism ,0104 chemical sciences ,Surfaces, Coatings and Films ,Degradation (geology) ,0210 nano-technology ,business - Abstract
Industries that work with acidic chemicals in their processes need to make choices on how to properly contain the substances and avoid rapid corrosion of equipment. Certain organic coatings and linings can be used in such environments, either to protect vulnerable construction materials, or, in combination with fiber reinforcement, to replace them. However, degradation mechanisms of organic coatings in acid service are not thoroughly understood and relevant quantitative investigations are scarce. This review describes the uses and limitations of acid-resistant coatings in the chemical industry, with a comparison to alternative resistant materials based on metals or ceramics. In addition, coating degradation phenomena, caused by acid exposure, are mapped to the extent possible, and analysis methods for detecting coating degradation type and severity are listed and discussed. It is concluded that more knowledge on chemical and physical degradation mechanisms is required, and that improvements in resistance to elevated temperatures and abrasion would decrease the risk of use and increase the potential application areas of organic coatings exposed to acidic environments in the chemical industry.
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- 2017
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9. Estimation of long-term drag performance of fouling control coatings using an ocean-placed raft with multiple dynamic rotors
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Asger Lindholdt, Stefan Møller Olsen, Søren Kiil, Kim Dam-Johansen, and Diego Meseguer Yebra
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Materials science ,Fouling ,Surfaces and Interfaces ,General Chemistry ,engineering.material ,Surfaces, Coatings and Films ,Biofouling ,Colloid and Surface Chemistry ,Coating ,Drag ,Parasitic drag ,Surface roughness ,Immersion (virtual reality) ,engineering ,Seawater ,Composite material - Abstract
An experimental setup was designed and built to estimate changes in the skin friction of fouling control coatings (FCC) over an extended period of time in conditions simulating the vast majority of ship profiles (regarding speed and activity) in the present market. The setup consisted of two separate parts: one aged FCCs directly in seawater in a dynamic manner by simulating the exposure condition of a ship’s hull, and a second, laboratory part measured the torque (drag) of aged coatings in a rotary setup. From the spring to the autumn of 2013 and 2014, four commercial FCCs were exposed for 53 weeks in Roskilde Fjord, Denmark, which is characterized by relatively cold seawater and a salinity of approximately 1.2 wt%. The in situ immersion seawater conditions consisted of five-week cycles divided into 2 weeks of static immersion and 3 weeks of dynamic immersion, during which time the cylinders were rotated at a tangential velocity of 8.1 knots. The skin friction was found to generally increase more during the static period, compared to the dynamic ones. Over the course of the entire exposure period, the skin friction of the investigated FCCs decreased in the following order: fluorinated fouling release coating (FRC) (highest skin friction), hydrogel-based FRC without biocides, silylated acrylate self-polishing copolymer coating, and hydrogel-based FRC with biocides (lowest skin friction). However, the differences in skin friction between the latter three coatings were minor and often within the range of experimental uncertainty. The average surface roughness of the FCCs in the newly applied and mechanically cleaned condition, determined as the Rt(50) and R z parameters, was evaluated as poor predictors of skin friction.
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- 2015
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10. Effects of biofouling development on drag forces of hull coatings for ocean-going ships: a review
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Diego Meseguer Yebra, Søren Kiil, Asger Lindholdt, Stefan Møller Olsen, and Kim Dam-Johansen
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Materials science ,Surfaces and Interfaces ,General Chemistry ,Computer Science::Computational Geometry ,engineering.material ,Surfaces, Coatings and Films ,Biofouling ,Colloid and Surface Chemistry ,Coating ,Parasitic drag ,Drag ,Hull ,engineering ,Forensic engineering ,Experimental methods ,Marine engineering - Abstract
This review presents a systematic overview of the literature and describes the experimental methods used to quantify the drag of hull coatings. It also summarizes the findings of hull coating’s drag performance and identifies the main parameters impacting it. The advantages and disadvantages of the reported methods listed in this review provide an assessment of the most efficient methods to quantify the drag performance of hull coatings. This review determines that drag performance of hull coating technology varies depending on whether the coating condition is newly applied, after dynamic or static seawater exposure. The summarized data reveal that, while several methods have attempted to quantify drag performance of hull coatings, other methods must be explored in order to accurately measure the long-term drag performance of hull coatings in conditions mimicking those that ship hulls encounter during actual voyages.
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- 2015
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11. Reduction of cathodic delamination rates of anticorrosive coatings using free radical scavengers
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Claus Erik Weinell, Kim Dam-Johansen, Søren Kiil, and Per Aggerholm Sørensen
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Reaction mechanism ,Materials science ,Radical ,Surfaces and Interfaces ,General Chemistry ,Epoxy ,engineering.material ,Free radical scavenger ,Peroxide ,Galvanization ,Surfaces, Coatings and Films ,Corrosion ,chemistry.chemical_compound ,symbols.namesake ,Colloid and Surface Chemistry ,chemistry ,Coating ,Chemical engineering ,visual_art ,visual_art.visual_art_medium ,symbols ,engineering ,Composite material - Abstract
Cathodic delamination is one of the major modes of failure for anticorrosive coatings subjected to a physical damage and immersed in seawater. The cause of cathodic delamination has been reported to be the result of a chemical attack at the coating–steel interface by free radicals and peroxides formed as intermediates in the cathodic reaction during the corrosion process. In this study, antioxidants (i.e., free radical scavengers and peroxide decomposers) have been incorporated into various generic types of coatings to investigate the effect of antioxidants on the rate of cathodic delamination of epoxy coatings on cold rolled steel. The addition of
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- 2010
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12. Replacement of traditional seawater-soluble pigments by starch and hydrolytic enzymes in polishing antifouling coatings
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J. B. Kristensen, Lars Thorslund Pedersen, Kim Dam-Johansen, Stefan Møller Olsen, and Søren Kiil
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Materials science ,Starch ,food and beverages ,Polishing ,Surfaces and Interfaces ,General Chemistry ,engineering.material ,Surfaces, Coatings and Films ,Biofouling ,chemistry.chemical_compound ,Hydrolysis ,Colloid and Surface Chemistry ,Coating ,chemistry ,Chemical engineering ,Agglomerate ,engineering ,Leaching (metallurgy) ,Composite material ,Dissolution - Abstract
The use of starch and hydrolytic enzymes as replacement for traditional polishing pigments (e.g., Cu2O and ZnO) in antifouling coatings has been investigated. The enzymes facilitate a slow conversion of water-insoluble starch into water-soluble glucose, and dissolution of glucose causes the development of a leached (porous) layer in the wetted, outermost part of the coating. Subsequent water–binder interaction at the pore walls gives rise to polishing, in a manner similar to that of conventional antifouling coatings. Different starch types have been evaluated and classified as potential coating ingredients, and the impact of the addition of starch on the functional properties of the coating is described. Starches from rice, corn, and tapioca have been tested, and due to a smaller amount of water-soluble content and lesser tendency to agglomerate, corn starch is preferred. Leaching occurs in all the starch-enzyme coatings tested; however, polishing is only detected for two out of four binder systems investigated. Suitable polishing rates of 7–10 μm/month, based on the enzymatic starch-degradation, have been measured. Controls containing only starch (no enzyme) did not polish.
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- 2009
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13. Effect and Modeling of Glucose Inhibition and In Situ Glucose Removal During Enzymatic Hydrolysis of Pretreated Wheat Straw
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Kim Dam-Johansen, Peter Arendt Jensen, Pavle Andric, and Anne S. Meyer
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Bioengineering ,Cellulase ,Applied Microbiology and Biotechnology ,Biochemistry ,chemistry.chemical_compound ,Hydrolysis ,Enzymatic hydrolysis ,Cellulose ,Molecular Biology ,Triticum ,Trichoderma reesei ,Trichoderma ,Chromatography ,biology ,Beta-glucosidase ,Aspergillus niger ,General Medicine ,biology.organism_classification ,Enzymes ,Kinetics ,Glucose ,Models, Chemical ,chemistry ,Product inhibition ,Biocatalysis ,biology.protein ,Biotechnology - Abstract
The enzymatic hydrolysis of lignocellulosic biomass is known to be product-inhibited by glucose. In this study, the effects on cellulolytic glucose yields of glucose inhibition and in situ glucose removal were examined and modeled during extended treatment of heat-pretreated wheat straw with the cellulolytic enzyme system, Celluclast 1.5 L, from Trichoderma reesei, supplemented with a beta-glucosidase, Novozym 188, from Aspergillus niger. Addition of glucose (0-40 g/L) significantly decreased the enzyme-catalyzed glucose formation rates and final glucose yields, in a dose-dependent manner, during 96 h of reaction. When glucose was removed by dialysis during the enzymatic hydrolysis, the cellulose conversion rates and glucose yields increased. In fact, with dialytic in situ glucose removal, the rate of enzyme-catalyzed glucose release during 48-72 h of reaction recovered from 20-40% to become approximately 70% of the rate recorded during 6-24 h of reaction. Although Michaelis-Menten kinetics do not suffice to model the kinetics of the complex multi-enzymatic degradation of cellulose, the data for the glucose inhibition were surprisingly well described by simple Michaelis-Menten inhibition models without great significance of the inhibition mechanism. Moreover, the experimental in situ removal of glucose could be simulated by a Michaelis-Menten inhibition model. The data provide an important base for design of novel reactors and operating regimes which include continuous product removal during enzymatic hydrolysis of lignocellulose.
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- 2009
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14. Anticorrosive coatings: a review
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Søren Kiil, Kim Dam-Johansen, Claus Erik Weinell, and Per Aggerholm Sørensen
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Ballast ,Materials science ,business.industry ,Metallurgy ,Context (language use) ,Surfaces and Interfaces ,General Chemistry ,engineering.material ,Durability ,Surfaces, Coatings and Films ,Corrosion ,Colloid and Surface Chemistry ,Petrochemical ,Coating ,Coating system ,Storage tank ,engineering ,Process engineering ,business - Abstract
The main objective of this review is to describe some of the important topics related to the use of marine and protective coatings for anticorrosive purposes. In this context, “protective” refers to coatings for containers, offshore constructions, wind turbines, storage tanks, bridges, rail cars, and petrochemical plants while “marine” refers to coatings for ballast tanks, cargo holds and cargo tanks, decks, and engine rooms on ships. The review aims at providing a thorough picture of state-of-the-art in anticorrosive coatings systems. International and national legislation aiming at reducing the emission of volatile organic compounds (VOCs) have caused significant changes in the anticorrosive coating industry. The requirement for new VOC-compliant coating technologies means that coating manufacturers can no longer rely on the extensive track record of their time-served products to convince consumers of their suitability for use. An important aspect in the development of new VOC-compliant, high-performance anticorrosive coating systems is a thorough knowledge of the components in anticorrosive coatings, their interactions, their advantages and limitations, as well as a detailed knowledge on the failure modes of anticorrosive coatings. This review, which mainly deals with European experience and practice, includes a description of the different environments an anticorrosive coating system may encounter during service. In addition, examples of test methods and standards for determination of the performance and durability of anticorrosive coatings have been included. The different types of anticorrosive coatings are presented, and the most widely applied generic types of binders and pigments in anticorrosive coatings are listed and described. Furthermore, the protective mechanisms of barrier, sacrificial, and inhibitive coatings are outlined. In the past decades, several alternatives to organic solvent-borne coatings have reached the commercial market. This review also presents some of these technologies and discusses some of their advantages and limitations. Finally, some of the mechanisms leading to degradation and failure of organic coating systems are described, and the reported types of adhesion loss are discussed.
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- 2009
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15. Inorganic precursor peroxides for antifouling coatings
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Lars Thorslund Pedersen, M. H. Hermann, Stefan Møller Olsen, Kim Dam-Johansen, and Søren Kiil
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Biocide ,Materials science ,Inorganic chemistry ,Oxide ,chemistry.chemical_element ,Surfaces and Interfaces ,General Chemistry ,Zinc ,engineering.material ,Surfaces, Coatings and Films ,Biofouling ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,chemistry ,Coating ,Chemical engineering ,engineering ,Zinc peroxide ,Leaching (metallurgy) ,Hydrogen peroxide - Abstract
Modern antifouling coatings are generally based on cuprous oxide (Cu2O) and organic biocides as active ingredients. Cu2O is prone to bioaccumulation, and should therefore be replaced by more environmentally benign compounds when technically possible. However, cuprous oxide does not only provide antifouling properties, it is also a vital ingredient for the antifouling coating to obtain its polishing and leaching mechanism. In this paper, peroxides of strontium, calcium, magnesium, and zinc are tested as pigments in antifouling coatings. The peroxides react with seawater to create hydrogen peroxide and highly seawater-soluble ions of the metal. The goals have been to establish the antifouling potency of an antifouling coating that releases hydrogen peroxide as biocide, and to investigate the potential use of peroxides as water-soluble polishing and leaching pigments. The investigations have shown that it is possible to identify particulates that, when applied as pigments in antifouling coatings, will provide polishing and leaching rates comparable to those of Cu2O-based coatings. Furthermore, the combination of polishing and hydrogen peroxide leaching by a coating based on zinc peroxide in a suitable binder matrix provides antifouling properties exceeding those of a similar coating based entirely on zinc oxide.
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- 2008
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16. [Untitled]
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Flemming Frandsen, Kim Dam-Johansen, and Stelios Arvelakis
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Municipal solid waste ,Waste management ,Fouling ,Incinerator bottom ash ,Chemistry ,Mineralogy ,chemistry.chemical_element ,Condensed Matter Physics ,Sulfur ,Corrosion ,Incineration ,Differential thermal analysis ,Physical and Theoretical Chemistry ,Thermal analysis - Abstract
The ash behaviour comprises one major obstacle towards the efficient utilization of municipal solid wastes, (MSW), in incineration plants. The presence of large amounts of inorganic constituents such as alkali and alkali earth metals, chlorine, sulfur and zinc increase significantly the ash reactivity and lead to severe ash-related problems such as fouling, slagging, corrosion and erosion during their thermal treatment. In this paper, the melting behaviour of various ash fractions originating from the incineration of MSW is studied using simultaneous, (DSC/TG), thermal analysis methods. The produced results provide the basis for improved modelling of the ash behaviour during the incineration of MSW.
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- 2003
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17. [Untitled]
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Flemming Frandsen, Anker Degn Jensen, Kim Dam-Johansen, Roberta Cenni, Alfredo Zolin, and Mette Stenseng
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Thermogravimetric analysis ,business.industry ,Chemistry ,Mineralogy ,Biomass ,Coal ,Char ,Thermal analysis ,business ,Process engineering ,Combustion ,Solid fuel ,Pyrolysis - Abstract
Thermal analysis is widely used in combustion research for both fundamental and practical investigations. Efficient combustion of solid fuels in power plants requires understanding of properties and behavior of fuel and ash under a wide range of conditions. At the Department of Chemical Engineering, Technical University of Denmark, thermogravimetric analysis and differential scanning calorimetry are applied in order to investigate various aspects of combustion and gasification processes: pyrolysis, char reactivity and ash melting behavior. This paper shows examples of the application of simultaneous thermal analysis in these three research areas, and it demonstrates the flexibility of this technique in combustion research.
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- 2001
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