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  • 1.
    Adamopoulos, Stergios
    Technological Educational Institute of Larissa, Greece.
    Fiber analysis techniques for sustainable manufacturing of corrugated board and packaging2006In: Proceedings of the 2006 Naxos International Conference on Sustainable Management and Development of Mountainous and Island Areas: 29th September - 1st October 2006, Island of Naxos, Greece / [ed] Evangelos I. Manolas, Democritus University of Thrace , 2006, Vol. 1, p. 1-9Conference paper (Refereed)
    Abstract [en]

    Environmental – economic pressure and associated regulations have led to a significant increase of recycled paper as the main fibrous component of corrugated board the last years. Corrugating packaging industry is facing the challenge to enhance products derived from recycled pulp and to ensure a satisfactory strength of packages. Advanced techniques are highly needed for the evaluation of packaging fiber supply sources as well as for the utilization of the available resources in an optimal manner. As industrial packaging is based on the characteristics of its constituent fibers, information on the fiber composition of the recycled raw materials is of primary importance for a continual control of fiber sources. This paper reports on the usefulness of fiber analysis techniques as diagnostic methods for assessing the potential quality distribution of fibers for sustainable packaging manufacturing.

  • 2.
    Adamopoulos, Stergios
    AIDIMA, Spain.
    Identification of Fibre Components in Packaging Grade Papers2006In: IAWA Journal, ISSN 0928-1541, Vol. 27, no 2, p. 153-172Article in journal (Refereed)
    Abstract [en]

    Environmental and economic issues have led to a significant increase of recycled paper as the main fibrous component of corrugated board the last years. Qualitative data on the different fibre types are needed for the evaluation of packaging fibre supply sources, which are becoming numerous and heterogeneous. Fifteen different packaging grade papers (7 linerboards and 8 corrugating medium) were selected to represent all the variety of papers available on the Spanish market. The origin of virgin and recycled fibres was identified by their morphological characteristics employing light microscopy and standard fibre analysis techniques. The waste-based papers (Waste based-liners and Fluting), Kraft-liners and Test-liner were highly variable containing 9–18 different wood and nonwood components. Semi-chemical, with 5–13 components, was the less variable grade. Hardwoods were identified as the most important fibre component from a quantitative standpoint. All papers contained in their hardwood mix Betula, Eucalyptus and Populus in significant amounts. Fagus sylvatica and Tilia were also frequently observed and in some papers were amongst major hardwood components. Prominent softwood components were found to be Pinus sylvestris, P. pinaster, P. radiata, Picea, Larix and in some papers Pinus nigra. The lower presence of a variety of softwood, hardwood and nonwood (mainly grasses) species and genera was due to the paper recycling process.

  • 3.
    Adamopoulos, Stergios
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Morphology, properties and recyclability of modified fibres and papers with different chemicals at laboratory, pilot plant and industrial trials2015Conference paper (Other (popular science, discussion, etc.))
  • 4. Adamopoulos, Stergios
    Quality control of packaging fiber sources2006Conference paper (Other academic)
  • 5. Adamopoulos, Stergios
    Quantification of softwood, hardwood and nonwood fibres in packaging grade papers2006In: TAPPI Journal, ISSN 0734-1415, Vol. 5, no 3, p. 27-32Article in journal (Refereed)
    Abstract [en]

    This study determined percentages by weight of the fiber components in 15 papers commonly used to produce corrugating packaging in Spain. The papers are manufactured mainly from recycled raw materials. The percentages were determined by means of standard quantitative fiber analysis techniques and use of appropriate weight factors. Hardwoods were the major fiber component in all papers, except kraft liners, varying from 51% to 92% per weight. Kraft liners had greater softwood content (49%-69%)than hardwood, and the most plentiful softwood classes were pines. Douglas-fir was a contaminating fiber component (weight percentage less than 2%) in almost in every paper. Nonwood fibers, entering the papers through the recycling process, were a significant fiber component (2%-9%) in most of the papers, especially the waste-based papers (liners and flutings). Quantitative fiber composition reflects the differences in quality between the papers. Its usefulness could be further explored in the quality control of paper manufacturing for packaging.

    Application: Packaging grade papers incorporate a variety of wood and nonwood fiber types. Manufacturing of papers of consistent and acceptable quality requires knowledge concerning the quantity of each fiber used.

  • 6.
    Adamopoulos, Stergios
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Birmpilis, D
    Technological Educational Institute of Thessaly.
    Use and properties of recovered paper raw materials for the production of corrugated board2015In: Proceedings of the 14th International Conference on Environmental Science and Technology Rhodes, Greece, 3-5 September 2015, Global NEST , 2015Conference paper (Refereed)
    Abstract [en]

    The difficulty of predicting the properties of paper products produced from heterogeneous sources puts several limitations, which therefore lead to severe economic losses and only a comprehensive characterization will enable their better utilization. The project “RF-CORRUG –Quality control of raw materials from recovered fibres for the production of corrugated board”under the NationalStrategic Reference Framework 2007–2013 ARCHIMEDES IIIdeals with this common technical problem of the corrugated board industry. Specifically, the mainobjective of the project is to supportthe competitiveness of the corrugated board companies (mainly SMEs)by creatinga software tool based on practical models that can predict packaging grade paper properties from fibre data (qualitative, quantitative, morphological) used in their production. This paper presents information on the physical and mechanical properties of recovered packaging papers used in corrugated packaging. A number of different category papers (liners, flutings) used for corrugated board production in Greece were examined. The required paper properties included grammage, porosity, bursting strength, SCT, tensile strength and tearing resistance, and were measured by internationally recognized testersand standards. The data will be used to develop predictive models based on advanced statistical methods for the properties and performance of packagingaccording to information of their recovered raw paper materials.

  • 7.
    Adamopoulos, Stergios
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Karageorgos, Anthony
    Technological Educational Institute of Thessaly, Greece.
    Rapti, Elli
    Center for Research and Technology – Hellas (CERTH), Greece .
    Birbilis, Dimitris
    Technological Educational Institute of Thessaly, Greece.
    Predicting the Properties of Corrugated Base Papers Using Multiple Linear Regression and  Artificial Neural Networks2016In: Drewno, ISSN 1644-3985, Vol. 59, no 198, p. 61-72Article in journal (Refereed)
    Abstract [en]

    The difficulty in predicting the properties and behaviour of paper products produced using heterogeneous raw materials with high percentages of recovered fibres poses restrictions on their efficient and effective use as corrugated packaging materials. This work presents predictive models for the mechanical properties of corrugated base papers (liner and fluting-medium) from fibre and physical property data using multiple linear regression and artificial neural networks. The most significant results were obtained for the prediction of the tensile strength of liners in the cross direction from the origin (wood type, pulp method) of the fibres using linear regression, and the prediction of the compressive strength of fluting-medium in the longitudinal (machine) direction, according to the short-span test, using a neural network with one hidden layer with 6 neurons, with coefficients of determination at 95.14% and 99.28%, respectively

  • 8.
    Adamopoulos, Stergios
    et al.
    Technological Educational Institute of Larissa, Greece.
    Mai, C
    From wood fibre modification to paper technology: properties of fibres modified with DMDHEU and glutaraldehyde2011In: 3rd biennial International Fibre Engineering Conference, 24 – 26 May, Barcelona, Spain, 2011Conference paper (Other academic)
  • 9.
    Adamopoulos, Stergios
    et al.
    AIDIMA, Spain.
    Martinez, E
    AIDIMA, Spain.
    Ramirez, D.
    AIDIMA, Spain.
    Characterization of packaging grade papers from recycled raw materials through the study of fibre morphology and composition2007In: Global NEST. International Journal, ISSN 1108-4006, Vol. 9, no 1, p. 20-28Article in journal (Refereed)
    Abstract [en]

    The restrictions in availability of forest-based raw materials along with favourable environmental policies towards alternative sources of raw materials have forced corrugated packaging industry to shift towards recycled paper and other fibre sources such as non-wood and agro-residues. The variability in raw pulp materials with increasing percentages of recycled fibres is a very common technical problem for the corrugated packaging industry worldwide. Corrugating packaging production is facing the challenge to ensure a satisfactory strength of packages despite the increase of recycled paper as the main fibrous component. Sustainable manufacturing of papers of consistent and acceptable quality requests comprehensive characterization of the fibrous components, which are becoming more heterogeneous. Understanding the influence that heterogeneous recycled raw materials have on packaging grade paper properties offers great potential value to the corrugated board and packaging industry.

    57 linerboards and corrugating medium were selected to represent all the variety of paper grades available on the market at the moment for the production of corrugated board in Spain. The papers were analyzed for their fibre morphology (fibre length, fibre width, lumen diameter, cell wall width and flexibility) and fibre composition (softwood to hardwood and nonwood fibre count and weight) and their strength (compression, bursting and crushing resistance) was evaluated. All the determinations were in accordance with the relevant TAPPI Test Methods. The significant differences found in most of the anatomical characteristics, fibre composition and strength properties among the paper grades reflected the diverse raw materials used for their production as well as their qualitative differences. By means of simple correlation the influence of fibre characteristics and composition on the strength of the papers was determined under two different conditions, at 23 o C and 50% RH and at 20 o C and 90% RH.

    The results demonstrate that besides the physical-mechanical characterization of packaging grade papers, fibre anatomy and composition can be used successfully as a complementary practical test to predict the performance of papers. The application of the predicting correlations is proposed for the evaluation of the fibre supplies for the packaging industry. An enormous potential for cost reduction can be created by the selection of the most appropriate and inexpensive combination of grade papers for a specific packaging use

  • 10. Adamopoulos, Stergios
    et al.
    Mertinez, E
    Ramirez, D
    Characterization of packaging grade papers from recycled raw materials through the study of fibre morphology and composition2005In: Proceedings of the 9th International Conference on Environmental Science and Technology: Rhodes, Rhodes Island, Greece, 1 - 3 September 2005 ; Volume of Abstracts / [ed] University of the Aegean, 2005, Vol. A, p. 18-25Conference paper (Refereed)
  • 11.
    Adamopoulos, Stergios
    et al.
    Technological Educational Institute of Karditsa, Greece.
    Oliver, José-Vicente
    AIDIMA, Spain.
    Fiber composition of packaging grade papers as determined by the Graff “C” staining test2006In: Wood and Fiber Science, ISSN 0735-6161, Vol. 38, no 4, p. 567-575Article in journal (Refereed)
    Abstract [en]

    A qualitative and quantitative analysis of the fiber components of 15 representative papers that are used for the production of corrugated board was carried out by the Graff "C" staining test. The method of processing of softwood, hardwood, and nonwood fibers was determined under a light microscope by their color reactions with the stain. All papers, due to the use of recycled pulp raw materials in their manufacturing, were found to incorporate in their furnish fibers that had been produced with a variety of pulping processes: chemical, mechanical, and semi-mechanical. The recycled-based papers (recycled-liner and recycled-medium) were proved to be the most variable comprising 12-15 different fiber components, while in some of the semi-chemicals only up to 7 components were identified. The weight percentages of the fiber components calculated by the application of weight factors showed that in almost all papers the most important fiber component from a quantitative standpoint was hardwood unbleached kraft followed by softwood unbleached kraft. Besides hardwood unbleached semi-chemical pulp and mechanical softwood pulp that were also plentiful in the papers, there was a smaller number of other components which sum, however, accounted for a significant fraction in the total furnish weight. The results taken on the total softwood, hardwood, and nonwood fibers content of the papers demonstrate that Graff "C" staining test is adequate to analyze both the structure and quality of packaging grade papers in practical industrial testing.

  • 12.
    Adamopoulos, Stergios
    et al.
    Democritus University of Thrace, Greece.
    Oliver, José-Vicente
    AIDIMA, Spain.
    Qualitative and quantitative fibre analysis in recycled raw materials for packaging2006In: Forest products journal, ISSN 0015-7473, Vol. 56, no 2, p. 58-60Article in journal (Refereed)
    Abstract [en]

    Understanding the influence that heterogeneous recycled raw materials have on packaging-grade paper performance offers great potential value to the corrugated board and packaging industry. Fifty-seven linerboards and corrugating medium were selected to represent all the variety of paper grades available on the Spanish market at the moment for the production of corrugated board. The origin of softwood, hardwood, and nonwood fibers and their percentages by weight were determined with light microscopy and standard fiber analysis techniques.

  • 13. Adamopoulos, Stergios
    et al.
    Passialis, Costas
    Voulgaridis, Elias
    Fibre characteristics of papers used in European corrugated packaging industry2009In: ATIP. Association Technique de L'Industrie Papetiere, ISSN 0997-7554, Vol. 63, no 4, p. 14-21Article in journal (Refereed)
  • 14. Adamopoulos, Stergios
    et al.
    Passialis, Costas
    Voulgaridis, Elias
    Fibre characteristics of papers used in European corrugated packaging industry2008Conference paper (Refereed)
  • 15. Adamopoulos, Stergios
    et al.
    Passialis, Costas
    Voulgaridis, Elias
    Oliver, JV
    Utilization of recycled fibre materials in the European corrugated packaging industrial sector2008In: 2nd International Conference on Engineering for Waste Valorisation WasteEng08, June 3-5, Patras, Greece, 2008Conference paper (Refereed)
  • 16. Adamopoulos, Stergios
    et al.
    Voulgaridis, E
    Passialis, C
    Morphology and identification of fibre furnish components of papers used in the production of corrugated board2013In: Celuloza Si Harti, ISSN 1220-9848Article in journal (Refereed)
  • 17.
    Adamopoulos, Stergios
    et al.
    Technological Educational Institute of Thessaly, Greece.
    Voulgaridis, Elias
    Aristotle University of Thessaloniki, Greece.
    Passialis, Costas
    Aristotle University of Thessaloniki, Greece.
    CARACTERISTICILE MATERIALULUI FIBROS ŞI PROPRIETĂŢILEHÂRTIEI RECICLATE FOLOSITE ÎN FABRICAREA CARTONULUIONDULAT: Morphology and identification of fibre furnish components of papers used in the production of corrugated board2013In: 7th International Symposium on Advanced Technologies for the Pulp, Paper and Corrugated Board Industry, 2013Conference paper (Refereed)
    Abstract [en]

    The manufacture of corrugated board containers (boxes, trays, etc.) involves a productionchain integrated by paper manufacturers, semi-elaborates (corrugated board) manufacturers andcontainer manufacturers, the majority of which in Europe are SMEs. Nowadays, corrugated boardcontainers are mostly manufactured with recovered paper. The greatest threat faced by thementioned production chain is related to the lack of quality and availability of recovered paper asraw material. Specifically, one of the most important properties of packaging paper is itsmechanical strength, which depends mostly on the length of the fibres of which paper iscomposed. These fibres are longer in virgin pulps (those coming from papers obtained fromwood, i.e. not yet recycled). However, the high pressure on the demand - as well as the currenteconomic and ecological restrictions in the use of forest based materials - has led to a situation inwhich very little quantity of virgin fibre enters the recycling chain. This means that the strengthquality of recycled fibres - and by extension of the papers - is constantly decreasing with the ongoingrecycling cycles. In addition, recovered paper presents a very high variability, whatconstitutes an obstacle when it comes to manufacturing containers having homogeneousproperties fixed by the customers at fixed costs. The difficulty of predicting the properties ofpaper products produced from heterogeneous sources puts several limitations, which thereforelead to severe economic losses and only a comprehensive characterization will enable their betterutilization. The project “RF-CORRUG – Quality control of raw materials from recovered fibresfor the production of corrugated board” under the National Strategic Reference Framework 2007–2013 ARCHIMEDES III deals with this common technical problem of the corrugated boardindustry. Specifically, the main objective of the project is to support the competitiveness of thecorrugated board companies (mainly SMEs) by creating a software tool based on practical modelsthat can predict packaging grade paper properties from fibre data (qualitative, quantitative, morphological) used in their production. This papers presents information on fibres (qualitativeand quantitative analysis, morphology) and packaging papers (physical and mechanicalproperties) used in corrugated packaging. A number of different category papers (liners, flutings) used for corrugated board production in Greece were examined. The main fibre characterizingtechniques, employed were fibre furnish analysis, morphological analysis of fibre, lightmicroscopy, scanning electron microscopy (SEM). In addition, zero span tensile test was done tomeasure the average fibre strength of fibre. The required paper properties were measured byinternationally recognized testers and standards. The data will be used to develop predictivemodels based on advanced statistical methods for the properties and performance of packagingpapers according to information of their fibres.

  • 18.
    Adamopoulos, Stergios
    et al.
    Greece.
    Voulgaridis, Elias
    Greece.
    Passialis, Costas
    Greece.
    Recycled Waste Paper and the Corrugated Packaging Industry in Europe2009In: Proceedings of 24th International Conference on Solid Waste Technology and Management: Philadelphia, PA USA, March 15-18, 2009, 2009, p. 400-411Conference paper (Refereed)
  • 19.
    Ahmed, Sheikh Ali
    et al.
    Luleå University of Technology.
    Morén, Tom
    Luleå University of Technology.
    Hagman, Olle
    Luleå University of Technology.
    Cloutier, Alain
    Laval University, Canada.
    Fang, Chang-Hua
    Laval University, Canada.
    Elustondo, Diego
    Luleå University of Technology.
    Anatomical properties and process parameters affecting blister/blow formation in densified European aspen and downy birch sapwood boards by thermo-hygro-mechanical compression2013In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 48, no 24, p. 8571-8579Article in journal (Refereed)
    Abstract [en]

    Approximately, 13.5 % of the standing volume of productive forest land in Sweden is covered by birch and aspen, which provides the vast potential to produce value-added products such as densified wood. This study shows whether it is possible to densify those species with a thermo-hygro-mechanical (THM) process using heat, steam, and pressure. In this process, transverse compression on thin European aspen (Populus tremula) and downy birch (Betula pubescens) boards was performed at 200 °C with a maximum steam pressure of 550 kPa. To obtain a theoretical 50 % compression set, the press’s maximum hydraulic pressure ranged from 1.5 to 7.3 MPa. Preliminary tests showed that ~75 % of the birch boards produced defects (blisters/blows) while only 25 % of the aspen boards did. Mainly, radial delamination associated with internal checks in intrawall and transwall fractures caused small cracks (termed blisters) while blows are characterized by relatively larger areas of delamination visible as a bumpy surface on the panel. Anatomical investigations revealed that birch was more prone to those defects than aspen. However, those defects could be minimized by increasing the pre-treatment time during the THM processing.

  • 20.
    Ahmed, Sheikh Ali
    et al.
    Luleå University of Technology.
    Sehlstedt-Persson, Margot
    Luleå University of Technology.
    Morén, Tom
    Luleå University of Technology.
    Development of a new rapid method for mould testing in a climate chamber: preliminary tests2013In: European Journal of Wood and Wood Products, ISSN 0018-3768, E-ISSN 1436-736X, Vol. 71, no 4, p. 451-461Article in journal (Refereed)
    Abstract [en]

    The purpose of this study was to develop fast, simple and robust solid wood mould testing methods for the use in small-scale laboratory tests. The objective was to investigate mould susceptibility of different wood materials within the batches. The proposed method is based on natural contamination of non-sterile surfaces in climates conducive to mould growth. For this purpose, a climate chamber with regulated temperature and relative humidity was used. The conditioning chamber was divided into upper and lower chamber by a thin layer of stainless steel placed horizontally above the fan to minimise air circulation to the sample in the upper compartment. Mould-infected samples from outdoor tests were used as a source of mould inocula, and test trials were conducted on Scots pine (Pinus sylvestris L.) sapwood. Samples were suspended from the top of the upper chamber, and the chamber was exposed to different temperature and humidity levels. Severe mould infestation was observed after 12–14 days of incubation. Visual mould rating was then performed. Regardless of some constraints, this test method was very simple, fast, and effective. More importantly, unlike other test methods, it closely models mould infestation as it would occur under natural condition.

  • 21.
    Ahmed, Sheikh Ali
    et al.
    Luleå University of Technology.
    Sehlstedt-Persson, Margot
    Luleå University of Technology.
    Morén, Tom
    Luleå University of Technology.
    Mould susceptibility of Scots pine (Pinus sylvestris L.) sapwood: Impact of drying, thermal modification, and copper-based preservative2013In: International Biodeterioration & Biodegradation, ISSN 0964-8305, E-ISSN 1879-0208, Vol. 85, p. 284-288Article in journal (Refereed)
    Abstract [en]

    The development of mould on wood surfaces depends on several factors. Although mould does not affect the mechanical properties of wood, it greatly reduces the aesthetic value of wood such as the sapwood of Scots pine (Pinus sylvestris L.), which is very prone to mould. In addition, adverse health effects of mould on humans are a great concern. Different types of dried and treated wood were used to observe whether they had enhanced durability against mould following an accelerated laboratory test method in a climate chamber. Samples were green, air-dried, industrially thermally modified, treated with copper-based preservative, and kiln-dried wood, which were tested within a single test run. The test produced the following main results: The thermal modification increased the durability of the wood, and the protective effectiveness of alternative treatments was comparable to that of commercially available copper-based treatment. However, the initial moisture content of the samples during mould exposure had a great influence on the onset of mould growth. The risk of mould susceptibility of industrial kiln-dried lumber can be reduced by drying using the double-layering technique and planing off the nutrient enriched evaporation surfaces.

  • 22. Balea, A
    et al.
    Blanco, A
    Fuente, H
    Concepción, M
    Negro, C
    Adamopoulos, Stergios
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Hosseinpourpia, Reza
    Mai, C
    Tubek-Lindblom, A
    Hansen, P
    Morphology, properties and recyclability of modified fibres and papers with different chemicals at laboratory and pilot plant trials2015In: 46th Congresso Annuale Aticelca, May 28-29, Sestri Levante-Genova, Italy, Aticelca , 2015, p. 23-31Conference paper (Refereed)
    Abstract [en]

    Fibre+ (2012-2015) is a European project aiming to develop potential treatments for recovered fibre modification capable of improving the recyclability and the properties of recycled papers. This study reports on the results on fibre morphology, paper properties and recyclability of fibres and papers modified with different chemicals and approaches from both laboratory and pilot plant trials. Sixteen modification chemical agents were studied in a set of laboratory trials. The raw material used was 100% recycled paper grade from old corrugated board containers (OCC). The laboratory analysis to evaluate the effectiveness of fibre modifications treatments included FBRM for pre-screening of chemicals, preparation of laboratory control and modified handsheets to a target grammage of 80 g/m2, and measurement of the fibre morphology, recyclability and mechanical and physical properties of the modified handsheets. Based on the results of laboratory testing, Fibre+ modifications pilot plant trials were carried out at a FEX paper machine. Furthermore the effect of the better dispersion of the cPAM using an ECOWIRL was studied. The overall laboratory and pilot plant results were promising for further implementation of the Fibre+ modifications at industrial scale and projection of improvements of fibre and paper properties on the performance of packaging products thereof

  • 23. Blanco Suarez, A.
    et al.
    Hansen, P.
    Lopez Exposito, P.
    Thomsson, L.
    Oliver, JV
    Adamopoulos, Stergios
    Quality prediction of board boxes made from recycled paper2009Conference paper (Refereed)
  • 24. Bonnet, Marie
    et al.
    Johansson, Jimmy
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Water transport in hardwoods above FSP: case of birch2014Conference paper (Other academic)
  • 25.
    Briggert, Andreas
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Olsson, Anders
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Oscarsson, Jan
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Three-dimensional modelling of knots and pith location in Norway spruce boards using tracheid-effect scanning2016In: European Journal of Wood and Wood Products, ISSN 0018-3768, E-ISSN 1436-736X, Vol. 74, no 5, p. 725-739Article in journal (Refereed)
    Abstract [en]

    Knots and the orientation of fibres in timber are decisive for the stiffness and strength of boards. Due to large property variations between members, strength grading is necessary. High resolution information of the orientation of fibres, both on surfaces and within members, would enable development of more accurate grading methods than those available today. A step towards three-dimensional (3D) models of the fibre orientation of the entire board volume is the establishment of 3D knot models based on scanning. The light from a dot laser illuminating the surface of a softwood board will, due to the tracheid effect, spread more along the fibres than across resulting in the dot entering an elliptical shape. In this investigation both the shape of the ellipse and the direction of its major axis were used to estimate the 3D fibre orientation on board surfaces. Knot surfaces were identified where the angle between the estimated 3D fibre direction and an approximated direction of the board’s pith exceeded a threshold value. By means of algorithms based on polar coordinates, knot surfaces which belonged to the same physical knot visible on different sides of the board were identified and as a result the position, orientation and volume of each knot were determined. Based on this information, a more accurate position of the board’s pith along the board was calculated. The established models showed good agreement with physical boards. The models constitute a promising starting point for further development of strength grading methods based on tracheid-effect scanning.

  • 26.
    Ekstrand, Johan
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Enhancement of Phenol Formaldehyde Adhesive with Crystalline Nano Cellulose2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Abstract

    The wood industries to this day use almost exclusively petroleum derived adhesives that are based mainly on the reaction of formaldehyde with urea, melamine or phenol. These adhesives have low cost and good adjustable properties which makes it hard for bio-based alternatives to compete. Phenol formaldehyde (PF), as an example of a synthetic adhesive, has been in use for over 100 years. In some parts of the world, legislation around formaldehyde is changing, and there is an increasingly voluntary awareness about the toxicity and unsustainability of formaldehyde. Industries realize that raw materials from oil is unstainable. The latter is currently a driving factor behind research on alternatives to amino based adhesives. Also, consumer interest in healthy and sustainable products, such as emitting less formaldehyde indoors, increases the need for bio based adhesives.

    Cellulose contained in plant cell walls is a renewable, abundant and nontoxic resource. During the last decades, many innovations have been achieved around cellulose and this trend does not seem to be slowing down. Cellulose shows excellent mechanical properties, high strength, high elastic modulus as well as having a low density.

    Research about cellulose reinforced adhesives has been increased the last years. This thesis studied the enhancement of phenol formaldehyde adhesive with Crystalline Nano Cellulose (CNC) at 5wt% and 10wt% loading levels for producing plywood boards. Indecisive results when using CNC higher than 3wt%, especially with PF resin, have been reported by other authors.

    In this thesis, European standards were applied. EN 314 was applied to test the panels shear strength. Three (3) treatment classes were selected, indoor room condition as well as pre-treatments 5.1.1 and 5.1.3. Other properties measured were modulus of elasticity, thickness swelling, formaldehyde emissions.

    Results showed a shear strength increase for all pre-treatment classes. 10wt% CNC mixture with phenol formaldehyde in water bath, pre-treatment (5.1.1) for 24h showed the highest increase in shear strength (+73,9%). The 10 wt% CNC mixture panels also showed the highest wood fibre failure of all panel types produced. A decrease in MOE has been observed with 10 wt% CNC compared to the 5 wt% CNC panels. Formaldehyde emissions tests were inconclusive, but since less PF was used, there was a general reduction in emissions. The 5 wt% CNC panels were superior in terms of modulus of elasticity and swelling and also showed improved shear strength. 

  • 27.
    Godinho, Pedro Miguel J.S.
    et al.
    Vienna University of Technology (TU Wien), Austria.
    Jajcinovic, Marina
    Graz University of Technology (TU Graz), Austria.
    Wagner, Leopold
    Vienna University of Technology (TU Wien), Austria.
    Vass, Viktoria
    Vienna University of Technology (TU Wien), Austria.
    Fischer, Wolfgang
    Graz University of Technology (TU Graz), Austria.
    Bader, Thomas K.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Hirn, Ulrich
    Graz University of Technology (TU Graz), Austria.
    Bauer, Wolfgang
    Graz University of Technology (TU Graz), Austria.
    Eberhardsteiner, Josef
    Vienna University of Technology (TU Wien), Austria.
    Hellmich, Christian
    Vienna University of Technology (TU Wien), Austria.
    A continuum micromechanics approach to the elasticity and strength of planar fiber networks: Theory and application to paper sheets2019In: European journal of mechanics. A, Solids, ISSN 0997-7538, E-ISSN 1873-7285, Vol. 75, p. 516-531Article in journal (Refereed)
    Abstract [en]

    2D materials such as planar fibrous networks exhibit several mechanical peculiarities, which we here decipher through a 3D-to-2D transition in the framework of continuum micromechanics or random mean-field homogenization theory. Network-to-fiber concentration (or “downscaling”) tensors are derived from Eshelby-Laws matrix-inclusion problems, specified for infinitely long, infinitely flat fibers, and for infinitely flat spheroidal pores of vanishing stiffness. Overall material failure is associated with microscopic shear failure orthogonal to the fiber direction. Corresponding structure-property relations between porosity on the one hand, and in-plane stiffness as well as strength on the other hand, appear as linear. This is in good agreement with mechanical experiments carried out on pulp fibers, on pulp fiber-to-pulp fiber bonds, and on corresponding paper sheets.

  • 28.
    Henrysson, Konrad
    Linnaeus University, Faculty of Technology, Kalmar Maritime Academy.
    Energikartläggning av ånga, processventilationssystemet och el på pappersmaskin 2, Stora Enso paper Nymölla AB: Energikartläggning utifrån lagen (2014:266) och ISO 50001:2011 på pappersmaskin 2.2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In order to improve the company's energy efficiency, a international law in 2014 was introduced to carry out energy surveys on companies with more than 250 employees, with annual income of more than 50 million euros, or over 43 million in total assets. Nymölla Bruk are included in this law and must therefore carry out energy mapping every four years and report it to the Swedish energy department. This law is the purpose for this degree project based to carrying out an energy survey on paper machine 2 in Nymölla Bruk.

    In the desiccator, 8.89 kg/s of water is evacuated from the paper with a gram weight of 120g/m2 and 10.45 kg/s with a gram weight of 80g/m2. The likely reason that it can evaporate more water from the paper in the lower grammage is that the paper is driven through the machine at a higher rate. The paper machine can produce 120g/m2 paper at a speed of 9.67 m/s and 80g/m2 paper at a speed of 12.22 m/s. The evaporating difference between gram weights can also be seen in the aftermath. The mass flow for point 20 which is at the exhaust air fan as shown in Figure 9 on page 25 of the report could not be reported due to the absence of a meter in place, and calculations for producing the mass flow did not work when the fan diagram from the fan manufacturers probably did not match the fan on which the measurements were made.

    In order to make an complete energy examination on this machine in regard of steam, condensate and process ventilation, it is necessary that the mass flow for point 20 can be known. The balance of the leakage into the dryer can not be determined without mass flow variable, making the energy consumption required to heat the air with steam impossible to calculate. Therefore, a further study should be done to carry out for making an complete energy examination.

  • 29.
    Hosseinpourpia, Reza
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Adamopoulos, Stergios
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Parsland, Charlotte
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Utilization of different tall oils for improving the water resistance of cellulosic fibers2019In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 136, no 13, article id 47303Article in journal (Refereed)
    Abstract [en]

    This study was conducted to assess the effect of the pulping by-products crude tall oil (CTO), distilled tall oil (DTO), andtall oil fatty acid (TOFA) on dynamic water vapor sorption behavior, interfiber strength, and thermal stability of cellulosic paper-sheets.The results were compared against those obtained in cellulose papers treated with the conventional petroleum-derived hydrophobicagent hydrowax and in untreated ones. The tall oil treatments caused strong reduction in equilibrium moisture content of the paper-sheets during adsorption and desorption runs. The same trend was noticed for the hydrowax-treated papers, however, it was lesspronounced than the CTO-treated and DTO-treated samples in the relative humidity range of 75–95%. The sorption hysteresis was con-siderably decreased after the treatments. The ultimate dry-tensile strengths of the paper-sheets were significantly reduced by TOFA andhydrowax treatments, while CTO and DTO showed comparable strength as that of untreated control. The ultimate wet-strengths of thepaper-sheets were improved after the treatments. The thermal stability of the specimens was improved by the tall oil treatments, and thehydrowax-treated samples illustrated lower degradation temperature than the untreated control. The results are promising for the use oftall oils as alternative hydrophobic agents of cellulosicfiber-based products, such as wood panels and paper packaging.

  • 30.
    Kumar, Anuj
    et al.
    Czech Technical University in Prague, Czech Republic ; University Centre for Energy Efficient Buildings of Technical University in Prague, Czech Republic.
    Ryparová, Pavla
    Czech Technical University in Prague, Czech Republic.
    Škapin, Andrijana Sever
    Slovenian National Building and Civil Engineering Institute, Slovenia.
    Humar, Miha
    University of Ljubljana, Slovenia.
    Pavlič, Matjaž
    University of Ljubljana, Slovenia.
    Tywoniak, Jan
    Czech Technical University in Prague, Czech Republic ; University Centre for Energy Efficient Buildings of Technical University in Prague, Czech Republic.
    Petr, Hajek
    Czech Technical University in Prague, Czech Republic ; University Centre for Energy Efficient Buildings of Technical University in Prague, Czech Republic.
    Žigon, Jure
    University of Ljubljana, Slovenia.
    Petrič, Marko
    University of Ljubljana, Slovenia.
    Influence of surface modification of wood with octadecyltrichlorosilane on its dimensional stability and resistance against Coniophora puteana and molds2016In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 23, p. 3249-3263Article in journal (Refereed)
    Abstract [en]

    A relatively new approach for wood protection against fungal decay is based on hydrophobization of wood and on lowering its moisture content. Water repellence of wood can be increased by polymerization of hydrophobic monomers in wood cell walls. It was found that Norway spruce wood after treatment with octadecyltrichlorosilane exhibited reduced water uptake by the wood cell walls, lowered water vapour sorption, and significantly increased dimensional stability of wood in terms of anti-swelling efficiency. Hydrophobicity and lower equilibrium moisture content were shown to cause increased resistance of the treated samples against brown-rot decay and molds.

  • 31.
    Maletič, Damjan
    et al.
    University of Maribor, Slovenia.
    Lovrenčič, Viktor
    C&G D.O.O. Ljubljana, Slovenia.
    Maletič, Matjaž
    University of Maribor, Slovenia.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Gomišček, Boštjan
    University of Maribor, Slovenia.
    Maintenance Solutions for Cost-Effective Production: A Case Study in a Paper Mill2015In: Engineering Asset Management - Systems : Professional Practices and Certification: Proceedings of the 8th World Congress on Engineering Asset Management (WCEAM 2013) & the 3rd International Conference on Utility Management & Safety (ICUMAS) / [ed] Tse, PW; Mathew, J; Wong, K; Lam, R; Ko, CN, Springer, 2015, p. 375-385Conference paper (Refereed)
    Abstract [en]

    For companies, in order to stay competitive, it is necessary to continuously increase the effectiveness and efficiency of their production processes. Therefore the purpose of this chapter is to discuss the role of maintenance in achieving the competitive advantages using cost-effectiveness aspect of maintenance process. In this regard, the chapter illustrates/discusses the impact of mechanical and electrical failures on company’s business on an example of a paper mill where processes are running 24/7. Thus, this paper presents the role of vibration-based maintenance (VBM) in enhancing the production and maintenance performance continuously and cost-effectively. Using empirical data collected from a paper mill case study, we found that company could avoid the profit losses even to a greater extent if it would improve the effectiveness of the VBM. With respect to the electrical causes of failures, a live working technique for improving the reliability and availability of the paper machine is proposed. Therefore, maintenance solution concerning the paper machine is suggested and discussed as well as potential benefits are highlighted. The results supported the notion that there is a positive association between the reduction of the unplanned stoppages and potential savings. The results have also shown that there is a need for more systematic approach, and a more holistic view of the maintenance function for establishing and running a cost-effective maintenance policy in the paper mill under consideration.

  • 32.
    Ormarsson, Sigurdur
    et al.
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design. Chalmers University of Technology, Sweden.
    Johansson, Marie
    Chalmers University of Technology, Sweden.
    Finite element simulation of growth stress formation and related board distortions resulting from sawing and forced drying2006In: New Zealand Journal of Forestry Science, ISSN 0048-0134, E-ISSN 1179-5395, Vol. 36, no 2, p. 408-423Article in journal (Refereed)
    Abstract [en]

    Matching timber quality with end-user requirements is a major research issue and lack of straightness in timber is the most frequent complaint worldwide. The final distortion of timber boards is caused mostly by moisture-related deformations and growth stresses that develop during growth of the tree, but how much the growth rate and growth stresses affect the final shape stability is not fully understood. A finite element analysis in which stress development during tree growth was simulated was performed with the aim of better understanding how growth stresses are generated. The tree growth model was formulated in terms of large strain settings (large changes in volume), whereas the material model for stress development was based on the theory of small strains. An earlier three-dimensional distortion model was developed further for studying the influence of growth stresses on final distortion of the board. The results showed that growth stresses clearly vary during tree growth and they also form a large stress gradient from pith to bark. This itself can result in significant bow and crook deformation when the log is sawed into boards.

  • 33.
    Pivnenko, Kostyantyn
    et al.
    Technical University of Denmark, Denmark.
    Eriksson, Eva
    Technical University of Denmark, Denmark.
    Astrup, Thomas Fruergaard
    Technical University of Denmark, Denmark.
    Presence of potentially critical substances in waste paper2013In: Proceedings Sardinia 2013: fourteenth international waste management and landfill symposium, Cagliari, Italy: CISA Publisher , 2013Conference paper (Refereed)
    Abstract [en]

    The paper industry accounts for a significant share of the chemicals consumed by the industrial sector. Most of the chemicals used are additives, i.e. chemical substances added during pulp and paper preparation and final product manufacturing (conversion and printing) in order to facilitate the process itself as well as the quality or functionality of the final product. Such additives may be re-introduced to the paper production process once waste paper is recycled, leading to their accumulation and spreading in newly manufactured paper and board products. This study aimed at identification of the critical additives potentially present in paper products and quantification of a selected group of additives (Mineral Oil Hydrocarbons) in waste paper and board source segregated from Danish municipal solid waste.

  • 34. Valai, A
    et al.
    Birbilis, D
    Karageorgos, A
    Adamopoulos, Stergios
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Estimation of properties of recovered paper used for the production of corrugated board2015Conference paper (Refereed)
    Abstract [en]

    The objective of this paper was the estimation of corrugated board mechanical properties based on the fiber characteristics from recovered paper and some physical properties (mainly grammage and thickness). Two kind of papers (liners and flutings) used for corrugated board production in Greece were examined. After the experimental determination of a plenty of variables, linear regressions were developed among those variables. Regressions led to some linear models with significant correlations between mechanical properties and fiber characteristics or physical properties (grammage and thickness). For the recycled paper of the liners category, significant correlations were observed considering tensile strength, tearing strength and zero span strength. For the recycled paper of the flutings category, significant correlations were observed considering compression strength and tearing strength

1 - 34 of 34
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