| 1. |
- Adamopoulos, Stergios, et al.
(författare)
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Grammage and structural density as quality indexes of packaging grade papers manufactured from recycled pulps
- 2014
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Ingår i: Drewno. - 1644-3985. ; 57:191, s. 145-151
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Tidskriftsartikel (refereegranskat)abstract
- Corrugated packaging production is currently facing the challenge to ensure a satisfactory strength of packaging despite the continuous increase in recycled paper as the main fibrous component. This research addresses a very common technical problem for the corrugated board industry – the difficulty of predicting the properties of paper products produced from heterogeneous sources. Grammage and structural density, being easily available data, were examined as quality parameters of the most common categories of packaging paper in Europe. Grammage, ranging from 100 to 225 g/m2, has been found to be a dominant parameter for estimating the strength properties of paper.
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| 2. |
- Adamopoulos, Stergios, et al.
(författare)
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Predicting the Properties of Corrugated Base Papers Using Multiple Linear Regression and Artificial Neural Networks
- 2016
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Ingår i: Drewno. - 1644-3985. ; 59:198, s. 61-72
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Tidskriftsartikel (refereegranskat)abstract
- 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
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| 3. |
- Brolund, Johan, et al.
(författare)
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Bioenergy innovations and their determinants: A negative binominal count data analysis
- 2014
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Ingår i: Drewno. - 1644-3985. ; 57:192, s. 41-61
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Tidskriftsartikel (refereegranskat)abstract
- The research employed a negative binominal count data model approach to analyse the determinants of bioenergy innovations with a special focus on the effect of energy and climate policies. A panel of 14 OECD countries were analysed using patent counts for the period 1978-2009 as a proxy for innovations. The policies examined were feed-in tariffs, quota obligations and different types of investment support schemes. The study found that feed-in tariffs affected innovation positively but quota obligations did not. The results regarding investment support programs were ambiguous since the dummy variable representing strong investment policies was statistically significant whereas the continuous variable for investment support schemes was not. Another finding was that electricity prices seemed to be an important determinant of innovation and that the accumulated stock of knowledge in the bioenergy sector also had a positive impact on bioenergy innovation.
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| 4. |
- Gebresenbet, Girma, et al.
(författare)
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Economic analysis of the collection and transportation of pruned branches from orchards for energy production
- 2020
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Ingår i: Drewno-Wood. - 1644-3985. ; 63
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Tidskriftsartikel (refereegranskat)abstract
- This economic analysis contains a case study for a 100 ha apple orchard where a pruning-to-energy (PtE) strategy is employed. Technical aspects of pruned biomass harvesting in apple orchards are outlined, with emphasis on the efficient harvesting of pruning residues using a dedicated baling machine. Economic aspects are approached using economic performance metrics such as the net present value (NPV) and internal rate of return (IRR). It is found, for a 10-year project on the 100 ha orchard, that the NPV is (sic)5650, the IRR is 8.71% and the payback time is about 8.0 years. Sensitivity analysis revealed that the economic metrics are highly influenced by the quantity of prunings, orchard area, and the price of pruning residues at the final user. The distance from the orchard to the final user (6 km in the analysed case) and orchard labour costs are both less impactful. The analysis shows that pruned biomass harvesting is technologically feasible in apple orchards, while the obtained values of the economic metrics indicate the economic feasibility of such bioenergy solutions.
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| 5. |
- Jiang, Wen, et al.
(författare)
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Particleboards with Partially Liquefied Bark of Different Particle Sizes
- 2021
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Ingår i: Drewno. - : Instytut Technologii Drewna. - 1644-3985. ; 64:207, s. 43-57
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a novel method of partially liquefying bark sawmilling waste for use in making particleboards. Maritime pine (Pinus pinaster Ait.) bark of different particle sizes (fine, medium, coarse, and mixed) was partially liquefied in the presence of ethylene glycol as a solvent and sulphuric acid as a catalyst at 180 degrees C for 30 minutes. Single-layer particleboards were prepared by mixing partially liquefied bark (PLB) and wood chips at a ratio of 0.25 with no adhesives (group A) and at ratios of 0.25 or 0.1 with melamine-urea-formaldehyde (MUF) adhesives for additional bonding (groups B and C respectively). Mechanical and physical properties of the particleboards were tested according to European standards. The results showed that the boards in group A had lower densities, inferior mechanical properties and higher moisture content than those in groups B and C. Bark particle size had a significant effect on the mechanical properties of particleboards within each group. Additional MUF bonding and avoidance of coarse bark particles had a positive effect on mechanical properties. The thickness swelling (TS) and water absorption (WA) values of MUF-bonded boards were lower than those of boards without MUF, and greater addition of PLB produced particleboards with better water resistance. Bark particle size was not as critical for TS and WA as for mechanical properties. The overall results suggested using a bark particle size of < 2 mm for further studies.
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| 6. |
- Nilsson, Daniel, et al.
(författare)
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The importance of accurate measurement of comminuted logging residues’ moisture contents for small-scale forest owners
- 2016
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Ingår i: Drewno. - 1644-3985. ; 59:198, s. 99-110
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Tidskriftsartikel (refereegranskat)abstract
- Bioenergy from logging residues is an important contributor to Swedish energysupplies. Thus, accurate measurements of delivered logging residues’ energycontents are very important for both sellers and buyers. Deliveries’ energycontents are highly correlated with their moisture contents, and thus aredetermined in southern Sweden (and elsewhere) by measuring their masses andmoisture contents. There is insufficient knowledge, however, about the variation inmoisture content within and between deliveries, and hence the minimum numberof samples needed to obtain the required precision. Thus, these variations wereexamined in detail in the presented study. Nested analysis of the variance of theacquired data shows that at least nine samples are required to obtain estimates ofa delivery’s moisture content with a 3% margin of error. For high volume trade,such as that between forest companies and the energy-conversion industry,current measurement practices are sufficiently accurate. For private forest ownersmaking single deliveries, however, higher precision is required as inaccuratemeasurements can strongly affect prices.
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| 7. |
- Gustafsson, Stig-Inge, et al.
(författare)
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ON YELLOW DISCOLORATIONS WHEN DRYING OAK, QUERCUS ROBUR
- 2008
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Ingår i: DREWNO-WOOD. - Poznan, Poland : Instytut Technologii Drewna. - 1644-3985. ; 51:179, s. 29-44
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Tidskriftsartikel (refereegranskat)abstract
- Growing trees many times contain more water than wood. When wood is to be utilized in the form of furniture it must therefore be dried in a kiln-dryer. In such a dryer the climate is very humid and warm which is ideal for many microorganisms such as bacteria and fungi. During their metabolism they change the chemical environment which sometimes lead to undisireable effects such as discolorations. In this paper we have examined specimen from oak, Quercus robur, collected from some parquet floor factories in Sweden. During drying some of these wood battens were affected with yellow streaks and spots which made the wood impossible to use for flooring. By examining small samples of the battens in light, as well as in scanning electron microscopes, we found that fungi grew inside the wooden tissue. By cultivation on agar plates we found several species where one has been identified as Penicillium roqueforti and another one as Paecilomyces variotii. We have also found that these fungi are extremely sensitive to high pH-values, so by spraying the wood with solutions of high pH already in the sawmill will probably make this problem much smaller.
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| 8. |
- Gustafsson, Stig-Inge
(författare)
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The Strength Properties of Swedish Oak and Beech
- 2010
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Ingår i: Drewno. - Poznan Poland : Wood Technology Institute. - 1644-3985. ; 53:183, s. 67-83
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Tidskriftsartikel (refereegranskat)abstract
- Because of their economic impact most research on wood in Sweden is aimed at our needle-leaved species, i.e. pine and spruce. Sawmills and other industrial enterprises using these conifers are also in vast majority, both in number of employees and number of companies. However, there is a viable industrial branch in Sweden, i.e. furniture companies, dealing with broad-leaved species such as oak, birch, and alder. Such industries often import all the wood they use, even if the same type of wood grows in the vicinity. In order to make the Swedish broad-leaved trees more interesting to the wood manufacturing sector, we examined the strength properties of some common Swedish woods, viz. oak and beech. The result shows that our oak specimens had a modulus of elasticity of 12.243 MPa measured by using four-point bending. So-called the Young’s modulus was 11.761 MPa for tension and 15.610 MPa for compression in the fibre direction, i.e. there was a very high difference. The stress just before rupture was measured to 85 MPa for tension and 76 MPa for compression, i.e. there was a surprisingly small difference. For beech, our corresponding values were 13.017 MPa for four-point bending, the Young’s modulus during tension was13.954 MPa and 130.4 MPa in maximum stress, whilst under compression these values were 13.101 MPa and 84 MPa, respectively.
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