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Publications (10 of 65) Show all publications
Vasco, D. A., Salinas-Lira, C., Barra-Reyes, I. & Elustondo, D. M. (2018). Kinematic characterization of the pressure-dependent PCM impregnation process for radiata pine wood samples. European Journal of Wood and Wood Products, 76(5), 1461-1469
Open this publication in new window or tab >>Kinematic characterization of the pressure-dependent PCM impregnation process for radiata pine wood samples
2018 (English)In: European Journal of Wood and Wood Products, ISSN 0018-3768, E-ISSN 1436-736X, Vol. 76, no 5, p. 1461-1469Article in journal (Refereed) Published
Abstract [en]

This paper reports on the properties of Pinus radiata wood impregnated with an organic phase change material (O-PCM). The tests are aimed at characterizing the kinetics of impregnation (rates, flows, and fronts) and the thermophysical properties (thermal conductivity and specific heat). In particular, a paraffin type O-PCM (octadecane) is used to impregnate dry radiata pine wood in the tangential flow direction at four manometric pressures (0, 1, 2, and 3 bar) and constant temperature of 50 °C. The wood is sapwood from 12-year old P. radiata growing in the Bío-Bío region and dimensioned according to Chilean standard for treated wood sample extraction. The results show that it is viable to impregnate P. radiata wood with O-PCM to improve its thermophysical properties with the purpose of passive conditioning.

Place, publisher, year, edition, pages
Springer, 2018
National Category
Other Mechanical Engineering
Research subject
Wood Science and Engineering
Identifiers
urn:nbn:se:ltu:diva-70295 (URN)10.1007/s00107-018-1335-7 (DOI)000440691200010 ()
Note

Validerad;2018;Nivå 2;2018-08-09 (andbra)

Available from: 2018-08-09 Created: 2018-08-09 Last updated: 2018-08-16Bibliographically approved
Grimm, A., Elustondo, D., Mäkelä, M., Segerström, M., Kalén, G., Fraikin, L., . . . Larsson, S. H. (2017). Drying recycled fiber rejects in a bench-scale cyclone: Influence of device geometry and operational parameters on drying mechanisms. Fuel processing technology, 167, 631-640
Open this publication in new window or tab >>Drying recycled fiber rejects in a bench-scale cyclone: Influence of device geometry and operational parameters on drying mechanisms
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2017 (English)In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 167, p. 631-640Article in journal (Refereed) Published
Abstract [en]

Significant amounts of waste sludge and rejects are generated by pulp and paper mills, and stricter environmental regulations have made waste handling a global challenge. Thermochemical conversion of mechanically dewatered by-products is expensive and inefficient due to their high moisture content; therefore drying is a vital unit operation in waste management. This paper reports results from drying of light coarse fiber reject in a bench-scale cyclone that allows changes in geometry. For the sake of comparison, convective fixed-bed drying tests were also performed. The results showed that the drying rate in the cyclone was hundreds of times higher than in the fixed-bed. For cyclone drying, the inlet air velocity was the most important factor in both determining the drying rate and residence time of the material. This led to the hypothesis that grinding of the reject particles due to particle-wall and particle-particle collisions play a crucial role in enhancing the efficiency of heat and mass transfer. In addition to inlet air velocity, cyclone geometry was the main factor that determined particle residence time, as drying air temperature mainly determined drying rate.

Place, publisher, year, edition, pages
Elsevier, 2017
National Category
Other Mechanical Engineering
Research subject
Wood Science and Engineering
Identifiers
urn:nbn:se:ltu:diva-65254 (URN)10.1016/j.fuproc.2017.08.004 (DOI)000413126400063 ()2-s2.0-85027333505 (Scopus ID)
Note

Validerad;2017;Nivå 2;2017-08-28 (andbra)

Available from: 2017-08-22 Created: 2017-08-22 Last updated: 2017-11-24Bibliographically approved
Salvo, L., Leandro, L., Contreras, H., Cloutier, A., Elustondo, D. M. & Ananías, R. A. (2017). Radial variation of density and anatomical features of Eucalyptus Nitens trees. Wood and Fiber Science, 49(3), 301-311
Open this publication in new window or tab >>Radial variation of density and anatomical features of Eucalyptus Nitens trees
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2017 (English)In: Wood and Fiber Science, ISSN 0735-6161, Vol. 49, no 3, p. 301-311Article in journal (Refereed) Published
Abstract [en]

This paper studies the relationship between apparent density and some anatomical propertiesof Eucalyptus nitens such as vessel frequency, vessel area, ring width, fiber cell wall thicknesses, andfiber length. The study involved 29 trees from 10 families of Eucalyptus nitens cut from a 17-yr-oldplantation in Southern Chile. The properties were determined along the radial direction of the trees byusing X-ray equipment and at selected positions through microscope and fiber quality analyzer equipment.The results showed that the anatomical properties of E. nitens did not change gradually from pith tobark, but they were better described by dividing the tree radius into three different wood-zones referred as inner-, middle-, and outer-wood. The apparent density of E. nitens was dependent of the vessel area,cell wall area, ring width, and latewood width. The correlation coefficient between apparent density andvessels area was negative and the correlation coefficient between apparent density and cell wall area,latewood ring width, and total ring width were positive. These means that E. nitens wood with lowerdensity tended to have higher vessel area, and lower fiber cell wall area, ring width, and latewood width.

Place, publisher, year, edition, pages
Society of Wood Science and Technology, 2017
Keywords
Earlywood, fiber, latewood, apparent density, ring width, solid lumber, vessel, X-ray densitometry
National Category
Other Mechanical Engineering
Research subject
Wood Science and Engineering
Identifiers
urn:nbn:se:ltu:diva-64887 (URN)000404813400007 ()2-s2.0-85029476523 (Scopus ID)
Note

Validerad; 2017; Nivå 2; 2017-08-16 (andbra)

Available from: 2017-07-17 Created: 2017-07-17 Last updated: 2017-11-24Bibliographically approved
Vikberg, T. & Elustondo, D. (2016). Basic density determination for Swedish softwoods and its influence on average moisture content of wood packages estimated by measuring their mass (ed.). Wood Material Science & Engineering, 11(4), 248-253
Open this publication in new window or tab >>Basic density determination for Swedish softwoods and its influence on average moisture content of wood packages estimated by measuring their mass
2016 (English)In: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 11, no 4, p. 248-253Article in journal (Refereed) Published
Abstract [en]

In this work, a set-up with a device measuring the mass of wood packages is examined as an aid to estimate the average moisture content (MC) of wood packages. As the basic density needs to be presumed in the set-up, an estimator of the basic density as a function of log diameter is determined for Norway spruce (Picea abies (L.) Karst) and Scots pine (Pinus sylvestris). In total, 1920 specimens were collected at two different sawmills and analysed for this purpose. Specimens collected at the butt-end of pine had the greatest variation in basic density and it is recommended that they should be omitted when sawmills create their own functions for basic density estimation. Furthermore, the variation in basic density was shown to have the greatest impact on the estimated MC. A maximum error estimator of the MC became 14% at a MC of 70% and 9% at a MC of 10%. It was therefore concluded that the described method should not be used to estimate the MC of packages after drying but can serve as a valuable indicator of average green MC of a drying batch.

National Category
Other Mechanical Engineering
Research subject
Wood Science and Engineering
Identifiers
urn:nbn:se:ltu:diva-4249 (URN)10.1080/17480272.2015.1090481 (DOI)000385568100007 ()2-s2.0-84945231902 (Scopus ID)22b38437-29ea-4e30-bc60-77409a90c393 (Local ID)22b38437-29ea-4e30-bc60-77409a90c393 (Archive number)22b38437-29ea-4e30-bc60-77409a90c393 (OAI)
Note

Validerad; 2016; Nivå 2; 20151006 (andbra)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Källander, B., Ormarsson, S. & Elustondo, D. (2016). Fuktförändringar, klimat och mögelpåväxt vid lagring av granvirke: Kalibrering av Finit Elementmodell för fuktförändringar (ed.). Paper presented at .
Open this publication in new window or tab >>Fuktförändringar, klimat och mögelpåväxt vid lagring av granvirke: Kalibrering av Finit Elementmodell för fuktförändringar
2016 (Swedish)Report (Other academic)
Alternative title[en]
Moisture changes, climate and mold growth in spruce timber during storage : Calibration of finite elements model for moisture changes
Abstract [en]

A diffusion based Finite Element- model designed to calculate changes in moisture content distribution in packages of wood during storage has been calibrated by means of combined measurements of climate and moisture content in a test package. Moisture content distribution before and after storage has been determined by dry mass measurements and X- ray Computer Tomography (CT- scanning). CT- scanning was done on individual planks to reduce interference from surrounding material. As a complement to the measurements of climate and moisture content, the test material was inspected visually after storage to determine if mould growth had occurred.The results from the study show that the moisture flux within a package of wood is slower than the moisture flux theoretically estimated based on published diffusion coefficients of wood. The moisture flux from the interior of a plank to the surface is slower than the removal of moisture from the surface, also when the plank is within a closed package covered with plastic on five surfaces.The calibration of the Finite Element model makes it ready for calculations of changes in moisture content in wood with high accuracy.

Publisher
p. 18
National Category
Other Mechanical Engineering
Research subject
Wood Science and Engineering
Identifiers
urn:nbn:se:ltu:diva-25391 (URN)efedc9e0-3e03-4b64-b6ea-693256400f0f (Local ID)efedc9e0-3e03-4b64-b6ea-693256400f0f (Archive number)efedc9e0-3e03-4b64-b6ea-693256400f0f (OAI)
Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2017-11-24Bibliographically approved
Perez-Peña, N., Cloutier, A., Segovia, F., Salinas-Lira, C., Sepúlveda-Villarroel, V., Salvo-Sepúlveda, L., . . . Ananías, R. A. (2016). Hygromechanical strains during the drying of Eucalyptus nitens boards (ed.). MADERAS: Ciencia y Tecnología, 18(2), 235-244
Open this publication in new window or tab >>Hygromechanical strains during the drying of Eucalyptus nitens boards
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2016 (English)In: MADERAS: Ciencia y Tecnología, ISSN 0717-3644, E-ISSN 0718-221X, Vol. 18, no 2, p. 235-244Article in journal (Refereed) Published
Abstract [en]

Collapse and drying stresses are currently induced during the drying of Eucalyptus nitens in solid wood products. The purpose of this study was to investigate these drying stresses by measuring hygromechanical strains during the drying of Eucalyptus nitens boards. Small samples of Eucalyptus nitens wood were oriented in the radial and tangential directions and tested to determine the hygromechanical strains during the drying process. This experimental work consisted of cantilevered bending tests conducted under variable relative humidity conditions. Tests were performed in a conditioning chamber at 30 °C with an equilibrium moisture content ranging from 22 to 12% under four levels of stress: 0, 10, 20 and 30% of the rupture load. The strains were determined using strain gauges, and the total deflection was measured with a linear variable differential transformer. The results show that in hygromechanical strains during the drying of Eucalyptus nitens, both the surface deformation and mechano-sorption strain were found to be proportional to the applied stress and reached their maximum values in the tangential direction. The total deflection increased 0.18 mm/mm with a surface deformation of 0.20 mm/mm, and the mechano-sorptive strain provides a greater contribution with a value of 0.11 mm/mm, thus corresponding to 59% of the total deformation. In attempts to improve the drying schedules of Eucalyptus nitens to develop solid wood products, mechano-sorptive behavior may be applied to relieve collapse and drying stress.

National Category
Other Mechanical Engineering
Research subject
Wood Science and Engineering
Identifiers
urn:nbn:se:ltu:diva-16269 (URN)10.4067/S0718-221X2016005000021 (DOI)000396793400001 ()2-s2.0-84994158174 (Scopus ID)fe6319dc-fe22-4d0d-bcbb-3038fdc079d8 (Local ID)fe6319dc-fe22-4d0d-bcbb-3038fdc079d8 (Archive number)fe6319dc-fe22-4d0d-bcbb-3038fdc079d8 (OAI)
Note

Godkänd; 2016; 20151219 (dieelu)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Torniainen, P., Elustondo, D. & Dagbro, O. (2016). Industrial Validation of the Relationship between Color Parameters in Thermally Modified Spruce and Pine (ed.). BioResources, 11(1), 1369-1381
Open this publication in new window or tab >>Industrial Validation of the Relationship between Color Parameters in Thermally Modified Spruce and Pine
2016 (English)In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 11, no 1, p. 1369-1381Article in journal (Refereed) Published
Abstract [en]

Thermal modification causes the darkening of wood throughout its cross-section because of chemical changes in the wood. After treatment, naturally light wood species look darker or even tropical, depending predominantly on the treatment temperature and processing time. This study investigates the suitability of using color measurement to determine treatment intensity at the industrial scale. The color was determined using the L*, a*, and b* color space, also referred to as CIELab, and the relationship between lightness (L*) and the color parameters (a*) and (b*) was investigated for thermal modification treatments at 190 and 212 °C. The wood species studied were pine (Pinus sylvestris L.) and spruce (Picea abies L.). The results showed that yellowness (+b*) and redness (+a*) had a significant prediction ability for class treatments at 190 and 212 °C, respectively. After treatment, there were no noticeable differences in color between the species, but sapwood was darker than heartwood in both untreated and thermally modified wood. The thickness of the boards had a proportionally darkening effect on the color values.

National Category
Other Mechanical Engineering
Research subject
Wood Science and Engineering
Identifiers
urn:nbn:se:ltu:diva-16140 (URN)fbad5e9a-10d5-4673-a1be-ba514c493eba (Local ID)fbad5e9a-10d5-4673-a1be-ba514c493eba (Archive number)fbad5e9a-10d5-4673-a1be-ba514c493eba (OAI)
Note

Validerad; 2016; Nivå 2; 20151219 (dieelu)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2017-11-24Bibliographically approved
Källander, B. & Elustondo, D. (2016). Influence of sample size during industrial and laboratory thermal modification on mass loss and impact bending strength of Scots pine (ed.). European Journal of Wood and Wood Products
Open this publication in new window or tab >>Influence of sample size during industrial and laboratory thermal modification on mass loss and impact bending strength of Scots pine
2016 (English)In: European Journal of Wood and Wood Products, ISSN 0018-3768, E-ISSN 1436-736XArticle in journal (Refereed) Submitted
National Category
Other Mechanical Engineering
Research subject
Wood Science and Engineering
Identifiers
urn:nbn:se:ltu:diva-16052 (URN)fa223de1-12c2-4b87-9f00-635e91985b53 (Local ID)fa223de1-12c2-4b87-9f00-635e91985b53 (Archive number)fa223de1-12c2-4b87-9f00-635e91985b53 (OAI)
Note

Upprättat; 2016; 20160525 (bjokal)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-04-19
Elustondo, D., Myronycheva, O., Sundqvist, B. & Karlsson, O. (2016). Localized Wood Surface Modification: Part I: Method Characterization. BioResources, 12(1), 283-295
Open this publication in new window or tab >>Localized Wood Surface Modification: Part I: Method Characterization
2016 (English)In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 12, no 1, p. 283-295Article in journal (Refereed) Published
Abstract [en]

This study assesses the potential of an open process for treatment of European Scots pine (Pinus sylvestris) with chemicals that could potentially make the surfaces stronger, more dimensionally stable, or more durable, depending on the treatment solution. The method provides an intermediate solution between full volume impregnation by pressure treatment and superficial surface treatment by dipping. Figuratively speaking, the process creates the equivalent of a layer of coating applied below the wood surfaces rather than above. Two different techniques were compared, namely, heating-and-cooling (H&C) and compression-and-expansion (C&E). Taking into account that commercial suppliers recommend 0.15 to 0.25 L/m2 of coating in sawn wood and 0.1 to 0.15 L/m2 in planed wood surfaces, then this study demonstrates that the H&C method can impregnate an equivalent amount of solution under the surfaces in less than 15 min using treatment temperatures below 150 °C.

Keywords
Scots pine, Wood surface modification, Heating-and-cooling, Compression-and-expansion
National Category
Other Mechanical Engineering
Research subject
Wood Science and Engineering
Identifiers
urn:nbn:se:ltu:diva-60328 (URN)10.15376/biores.12.1.283-295 (DOI)000397065200022 ()2-s2.0-85056572675 (Scopus ID)
Funder
VINNOVA
Note

Validerad; 2016; Nivå 2; 2016-12-03 (kribac)

Available from: 2016-11-11 Created: 2016-11-11 Last updated: 2018-12-03Bibliographically approved
Sepúlveda-Villarroel, V., Perez-Peña, N., Salinas-Lira, C., Salvo-Sepúlveda, L., Elustondo, D. & Ananías, R. A. (2016). The Development of Moisture and Strain Profiles During Pre-Drying of Eucalyptus nitens (ed.). Drying Technology, 34(4), 428-436
Open this publication in new window or tab >>The Development of Moisture and Strain Profiles During Pre-Drying of Eucalyptus nitens
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2016 (English)In: Drying Technology, ISSN 0737-3937, E-ISSN 1532-2300, Vol. 34, no 4, p. 428-436Article in journal (Refereed) Published
Abstract [en]

This paper describes one of a series of studies carried out at the University of Bio-Bio in Chile with the objective of characterizing the response of Eucalyptus nitens to drying. The ultimate goal is to minimize collapse and internal intra-ring checking in the industrial drying of Eucalyptus nitens, which currently prevents the lumber manufacturing industry in Chile from producing a large number of commercial solid wood products from this species. This study focuses, however, on the drying conditions that have been shown in previous studies and are known in the industry to minimize collapse and internal intra-ring checking. For these conditions, this study reports the development of moisture content and internal strain profiles during drying. In addition, a simple diffusion model based on the concept of the effective diffusion coefficient was proposed to compare the drying rates in the radial and tangential directions. The results showed that the diffusion coefficient in the radial direction was approximately 50% higher than that in the tangential direction. Internal strains, on the other hand, developed approximately at the same time, regardless of the annual ring orientation. This indicates that it would be feasible to apply strain relief strategies simultaneously to all boards regardless of their annual ring orientation in order avoid internal intra-ring checking during pre-drying. This finding could be used as a benchmarking tool in the industrial drying for solid wood products of Eucalyptus nitens.

National Category
Other Mechanical Engineering
Research subject
Wood Science and Engineering
Identifiers
urn:nbn:se:ltu:diva-14726 (URN)10.1080/07373937.2015.1060490 (DOI)000371089900006 ()2-s2.0-84958999237 (Scopus ID)e2484e6e-ec46-40fc-8b3a-291eba5ab105 (Local ID)e2484e6e-ec46-40fc-8b3a-291eba5ab105 (Archive number)e2484e6e-ec46-40fc-8b3a-291eba5ab105 (OAI)
Note

Validerad; 2016; Nivå 2; 20150817 (andbra)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-0744-5868

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