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| 2. |
- Adamopoulos, Stergios, et al.
(författare)
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Acoustic properties of acetylated wood under different humid conditions and its relevance for musical instruments
- 2018
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Ingår i: Proceedings of the 9th European Conference on Wood Modification 2018, Arnhem, The Netherlands. - The Netherlands : Practicum. ; , s. 236-243
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Konferensbidrag (refereegranskat)abstract
- In musical instrument making, less expensive wood species and materials with good characteristics and acoustical properties can provide potentials to find alternatives to the traditional exotic wood species used today. Modified wood could be such a choice if shows similar sound characteristics to wood coming from endangered and expensive tropical species with problematic commercial availability. In musical instruments, the overall functionality depends on the contribution of wood to different material performance indexes like sound radiation coefficient (R), characteristic impedance (z) and acoustic conversion efficiency (ACE). In this study, the performance indexes were measured for acetylated beech, maple and radiata pine and compared with these obtained for the reference wood materials maple, mahogany, alder and ash. A non-destructive free-free flexural vibration test method was used at constant temperature (20oC) but in different humid conditions- dry (35% RH), standard (65% RH) and wet (85% RH). Dimensional changes in the different humid conditions were also taken in account. Acetylated wood showed lower EMC with higher dimensional stability at each humidity level as compared with the reference wood materials. These properties are considered important factors for making quality musical instruments. Based on the acoustical properties, acetylated wood materials, especially radiata pine, showed good potential for use for musical instruments where specific characteristics of sound are required. However, the other types of acetylated wood can also be used for specific musical instruments.
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| 3. |
- Adamopoulos, Stergios
(författare)
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Group of Forest Products
- 2018
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Ingår i: Presented at Symposium "Perspectives in Renewables", 4-5 June 2018, BOKU Vienna, Austria.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 4. |
- Adamopoulos, Stergios, et al.
(författare)
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Manufacturing and properties of gypsum-based products with recovered wood and rubber materials
- 2015
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Ingår i: BioResources. - : BioResources. - 1930-2126. ; 10:3, s. 5573-5585
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Tidskriftsartikel (refereegranskat)abstract
- The experimental production of gypsum-based products (cylindrical samples, solid bricks) using different fractions of wood chips and rubber particles was studied. Recovered rubber and wood materials were mixed with gypsum and water in various proportions to fabricate gypsum-wood and gypsum-rubber cylindrical samples and standard solid bricks with six holes using appropriate molds. It was shown that to manufacture gypsum-wood and gypsum-rubber products with good mechanical strength, coarse fractions of wood and rubber should be used, but the proportion of wood or rubber should not exceed 25%. No thermal conductivity differences were found between the wood-and rubber-type of gypsum products, and particle size and material proportion had no effect. Samples with fine wood and rubber particles present at a lower proportion (25%) exhibited similar sound absorption behavior. The solid bricks had slightly higher strength when loaded at the large surface of their lateral upper side than when loaded at the small surface. The bricks provided better thermal insulation than both the extruded and pressed house bricks but lower than that of insulating bricks. The emission of volatile organic compounds out of the bricks was at an acceptable level according to regulations for construction products.
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| 6. |
- 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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| 7. |
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| 8. |
- Adamopoulos, Stergios, et al.
(författare)
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Tensile strength of handsheets prepared with macerated fibres from solid wood modified with cross-linking agents
- 2015
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Ingår i: Holzforschung. - : Walter de Gruyter. - 0018-3830 .- 1437-434X. ; 69:8, s. 959-966
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Tidskriftsartikel (refereegranskat)abstract
- This study was conducted to explain the tensile strength loss of wood due to the modification with 1,3-dimethylol-4,5-dihydroxyethyleneurea (DMDHEU) and glutaraldehyde (GA). Modified and control wood blocks were macerated to deliberate fibres, and handsheets were produced thereof. The nitrogen content of the fibres indicated that maceration removed the major proportions of DMDHEU. The stability of GA in wood during maceration was not assessed. Tensile strength determined at zero span (z-strength) and finite span (f-strength) was equal for the handsheets from DMDHEU-modified fibres and the control handsheets. The microscopic appearance of the tested finite-span paper strips from DMDHEU-modified fibres mainly indicated interfibre failure and did not differ from the fibre fracture mode of the control handsheets. In contrast, the z-strength of the handsheets from GA-modified fibres was lower than that of controls and decreased with increasing content of GA in the initial modified wood. The f-strength behaviour of the handsheets from GA-modified fibres was the opposite: it was higher than that of controls and increased with increasing GA content. The microscopic appearance of the rapture zones of the finite-span testing mainly indicated intrafibre failure for the GA-modified fibres. It was concluded that cross-linking is likely to be the major reason for tensile strength loss of GA- and DMDHEU-modified wood. In terms of DMDHEU-modified wood, the incrustation of the cell wall by the resin and the reduction in pliability could play an additional role.
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| 9. |
- Adamopoulos, Stergios, et al.
(författare)
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Use and properties of recovered paper raw materials for the production of corrugated board
- 2015
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Ingår i: Proceedings of the 14th International Conference on Environmental Science and Technology Rhodes, Greece, 3-5 September 2015. - : Global NEST. - 9789607475527
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Konferensbidrag (refereegranskat)abstract
- 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.
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