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Publications (10 of 14) Show all publications
Elmer, S., Danvind, J. & Holmberg, H.-C. (2013). Development of a novel eccentric arm cycle ergometer for training the upper body. Medicine & Science in Sports & Exercise, 45(1), 206-211
Open this publication in new window or tab >>Development of a novel eccentric arm cycle ergometer for training the upper body
2013 (English)In: Medicine & Science in Sports & Exercise, ISSN 0195-9131, E-ISSN 1530-0315, Vol. 45, no 1, p. 206-211Article in journal (Refereed) Published
Abstract [en]

Several investigators have demonstrated that chronic eccentric leg cycling is an effective method for improving lower body neuromuscular function (e.g., quadriceps muscle size, strength, and mobility) in a variety of patient and athletic populations. To date, there are no reports of using eccentricarm cycling (ECarm) as an exercise modality, probably in large part because of the lack of commercially available ECarm ergometers. Purpose: Our purposes for conducting this study were to 1) describe the design and construction of an ECarm ergometer and 2) compare ECarm to traditional concentric arm cycling (CCarm). Methods: All of the parts of a Monark 891E cycle ergometer (Monark Exercise AB, Vansbro, Sweden) were removed, leaving the frame and flywheel. An electric motor (2.2 kW) was connected to the flywheel via a pulley and a belt. Motor speed and pedaling rate were controlled by a variable frequency drive. A power meter quantified power and pedaling rate, and provided feedback to the individual. Eight individuals performed 3-min ECarm and CCarm trials at 40, 80, and 120 W (60 rpm) while V̇O2 was measured. Results: The ECarm ergometer was simple to use, was adjustable, provided feedback on power output to the user, and allowed for a range of eccentric powers. V̇O2 during ECarm was substantially lower compared with CCarm (P < 0.001). At similar V̇O2 (0.97 ± 0.18 vs 0.91 ± 0.09 L•min, for ECarm and CCarm, respectively, P = 0.26), power absorbed during ECarm was approximately threefold greater than that produced during CCarm (118 ± 1 vs 40 ± 1 W, P < 0.001). Conclusion: This novel ECarm ergometer can be used to perform repetitive, high-force, multijoint, eccentric actions with the upper body at a low level of metabolic demand and may allow researchers and clinicians to use ECarm as a training and rehabilitation modality. © 2012 by the American College of Sports Medicine.

Place, publisher, year, edition, pages
Lippincott Williams & Wilkins, 2013
Keywords
Eccentric muscle contraction, ergometry, multijoint exercise, power, rehabilitation
National Category
Sport and Fitness Sciences
Identifiers
urn:nbn:se:ltu:diva-84373 (URN)10.1249/MSS.0b013e318269c79c (DOI)000312535200028 ()22843110 (PubMedID)2-s2.0-84871615327 (Scopus ID)
Available from: 2013-01-08 Created: 2021-05-19 Last updated: 2021-10-15Bibliographically approved
Danvind, J. & Ekevad, M. (2006). Local water vapor diffusion coefficient when drying Norway spruce sapwood (ed.). Journal of Wood Science, 52(3), 195-201
Open this publication in new window or tab >>Local water vapor diffusion coefficient when drying Norway spruce sapwood
2006 (English)In: Journal of Wood Science, ISSN 1435-0211, E-ISSN 1611-4663, Vol. 52, no 3, p. 195-201Article in journal (Refereed) Published
Abstract [en]

In this article, a one-dimensional and a two-dimensional approach to the evaluation of local diffusion coefficients for Norway spruce sapwood from measured moisture content (MC) values are presented. A studied wood sample was dried from the initial green condition to about 15% mean MC, but here only the diffusive part of the drying process between approximately 25% and 15% mean MC was treated. Measured local MC values were based on nondestructive X-ray computed tomography data. Finite element calculations were performed with two alternative diffusion coefficients to test the appropriateness of the diffusion coefficients that were evaluated from the measured MC values. The evaluated diffusion coefficients show interesting dependence on MC and distance from the evaporation surface. The advantage of using the methods presented is that the diffusion coefficient is calculated on a local level without having to define a function for the diffusion coefficient's dependency on other parameters

National Category
Bio Materials Other Mechanical Engineering
Research subject
Wood Physics; Wood Technology
Identifiers
urn:nbn:se:ltu:diva-5622 (URN)10.1007/s10086-005-0753-4 (DOI)000237966100002 ()2-s2.0-33744532133 (Scopus ID)3c65f9b0-bb52-11db-b560-000ea68e967b (Local ID)3c65f9b0-bb52-11db-b560-000ea68e967b (Archive number)3c65f9b0-bb52-11db-b560-000ea68e967b (OAI)
Note
Validerad; 2006; 20061016 (cira)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2021-10-15Bibliographically approved
Eriksson, J., Johansson, H. & Danvind, J. (2006). Numerical determination of diffusion coefficients in wood using data from CT-scanning (ed.). Wood and Fiber Science, 38(2), 334-344
Open this publication in new window or tab >>Numerical determination of diffusion coefficients in wood using data from CT-scanning
2006 (English)In: Wood and Fiber Science, ISSN 0735-6161, Vol. 38, no 2, p. 334-344Article in journal (Refereed) Published
Abstract [en]

The radial moisture diffusion coefficient in Fick's law for a sample of Norway spruce (Picea abies) under isothermal drying conditions was determined in a parameterization of Arrhenius' equation type. Using X-ray CT-scanning, the wood density and moisture content distributions were obtained in the radial direction for the wood sample. An optimization scheme, based on finite element computation, was then applied to find the parameter values such that the difference between observed and computed moisture content was minimized. The combined numerical and experimental technique was developed to reduce known disadvantages of similar approaches, and a specific algorithm to determine diffusion coefficients was presented. A comparison of the calibrated diffusion coefficient with those given in the literature showed a good fit. The computed moisture content based on the obtained diffusion coefficient and the observed moisture content agreed well. Finally, the effect of measurement errors on the computed material parameter was found to be small

National Category
Bio Materials
Research subject
Wood Physics
Identifiers
urn:nbn:se:ltu:diva-8667 (URN)733be8a0-bb52-11db-b560-000ea68e967b (Local ID)733be8a0-bb52-11db-b560-000ea68e967b (Archive number)733be8a0-bb52-11db-b560-000ea68e967b (OAI)
Note
Validerad; 2006; 20061016 (cira)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2021-10-15Bibliographically approved
Eriksson, J., Johansson, H. & Danvind, J. (2005). A mass-transport model for drying wood under isothermal conditions (ed.). In: (Ed.), (Ed.), Proceedings: 9th International IUFRO Wood Drying Conference. Paper presented at International IUFRO Wood Drying Conference : 21/08/2005 - 26/08/2005. : Nanjing Forestry University
Open this publication in new window or tab >>A mass-transport model for drying wood under isothermal conditions
2005 (English)In: Proceedings: 9th International IUFRO Wood Drying Conference, Nanjing Forestry University , 2005Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Nanjing Forestry University, 2005
National Category
Bio Materials
Research subject
Wood Physics
Identifiers
urn:nbn:se:ltu:diva-31299 (URN)571cfa30-0641-11dc-b09b-000ea68e967b (Local ID)571cfa30-0641-11dc-b09b-000ea68e967b (Archive number)571cfa30-0641-11dc-b09b-000ea68e967b (OAI)
Conference
International IUFRO Wood Drying Conference : 21/08/2005 - 26/08/2005
Note
Godkänd; 2005; 20070519 (ysko)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2021-10-15Bibliographically approved
Scheepers, G., Danvind, J., Morén, T. & Rypstra, T. (2005). An investigation of fluid water movement in birch during drying through variation of wood sap surface tension and initial average moisture (ed.). In: (Ed.), (Ed.), Proceedings: 9th International IUFRO Wood Drying Conference. Paper presented at International IUFRO Wood Drying Conference : 21/08/2005 - 26/08/2005. : Nanjing Forestry University
Open this publication in new window or tab >>An investigation of fluid water movement in birch during drying through variation of wood sap surface tension and initial average moisture
2005 (English)In: Proceedings: 9th International IUFRO Wood Drying Conference, Nanjing Forestry University , 2005Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Nanjing Forestry University, 2005
National Category
Bio Materials
Research subject
Wood Physics
Identifiers
urn:nbn:se:ltu:diva-26901 (URN)029f6140-0642-11dc-b09b-000ea68e967b (Local ID)029f6140-0642-11dc-b09b-000ea68e967b (Archive number)029f6140-0642-11dc-b09b-000ea68e967b (OAI)
Conference
International IUFRO Wood Drying Conference : 21/08/2005 - 26/08/2005
Note
Godkänd; 2005; 20070519 (ysko)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2021-10-15Bibliographically approved
Danvind, J. (2005). Analysis of drying wood based on nondestructive measurements and numerical tools (ed.). (Doctoral dissertation). Luleå: Luleå tekniska universitet
Open this publication in new window or tab >>Analysis of drying wood based on nondestructive measurements and numerical tools
2005 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Improved understanding of moisture and mechanical behaviour is a general objective for wood drying research. The main objective of this doctoral thesis was to develop nondestructive experimental methods suitable for collecting valuable response data related to the moisture behaviour and mechanical behaviour of drying wood and to refine this information into modelling parameters. A method for simultaneous noncontact measurement of two-dimensional surface deformations and interior densities was developed. This was done using Digital Speckle Photography (DSP) and X-ray Computed Tomography (CT). Displacements and densities were used for calculation of strain and of moisture content. Experimental tests of the measurement method were done on cross sections of Scots pine. The following accuracy was stated for different properties: A typical calculated displacement error of approximately 10 micrometre was found. Strains derived from the displacements had a maximal error of 1.11 mstrain. Moisture content measuring accuracy was estimated to +-1.8% moisture content at a significance level of 0.05 in a measuring volume with the approximate size 2 x 2 x 1.5 mm3. A similar noncontact technique based only on X-ray CT scanning was developed. Displacements were then estimated from boundary movements of an object in CT images. The estimated standard deviation of the measured moisture content error for this method was 0.04% moisture content. The mean error was unknown. Two different approaches to determining moisture diffusion coefficients from the studied data were presented. The first was based on minimizing the difference between measured and computed values through an optimization scheme. This approach required an initial assumption of the functional form of the diffusion coefficient. The second approach calculated diffusion and mass transfer coefficients through direct finite difference calculations on measured moisture content data. Results on Norway spruce showed interesting local variations of the diffusion coefficient, especially near the evaporation surface. Comparisons between measured and FEM simulated data showed good results. An example showed that a multivariate method of analysis could be an effective and easy-to-use tool for untangling relationships between variables and for generating information from data. Finally, it could be stated that the methods presented will be of use to improve the understanding of the behaviour of drying wood, with the focus on moisture and mechanical properties.

Place, publisher, year, edition, pages
Luleå: Luleå tekniska universitet, 2005. p. 32
Series
Doctoral thesis / Luleå University of Technology 1 jan 1997 → …, ISSN 1402-1544 ; 2005:23
National Category
Bio Materials
Research subject
Wood Physics
Identifiers
urn:nbn:se:ltu:diva-18059 (URN)6a1ee9c0-5225-11db-9592-000ea68e967b (Local ID)6a1ee9c0-5225-11db-9592-000ea68e967b (Archive number)6a1ee9c0-5225-11db-9592-000ea68e967b (OAI)
Note
Godkänd; 2005; 20061002 (ysko)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2021-10-15Bibliographically approved
Larsson, R., Danvind, J., Imbaud, O. & Morén, T. (2005). Prediction modelling of colour changes on boards of Norway Spruce and Scots Pine during low temperature drying (ed.). In: (Ed.), (Ed.), Proceedings: 9th International IUFRO Wood Drying Conference. Paper presented at International IUFRO Wood Drying Conference : 21/08/2005 - 26/08/2005. : Nanjing Forestry University
Open this publication in new window or tab >>Prediction modelling of colour changes on boards of Norway Spruce and Scots Pine during low temperature drying
2005 (English)In: Proceedings: 9th International IUFRO Wood Drying Conference, Nanjing Forestry University , 2005Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Nanjing Forestry University, 2005
National Category
Bio Materials
Research subject
Wood Physics
Identifiers
urn:nbn:se:ltu:diva-27754 (URN)14aa2200-0640-11dc-b09b-000ea68e967b (Local ID)14aa2200-0640-11dc-b09b-000ea68e967b (Archive number)14aa2200-0640-11dc-b09b-000ea68e967b (OAI)
Conference
International IUFRO Wood Drying Conference : 21/08/2005 - 26/08/2005
Note
Godkänd; 2005; 20070519 (ysko)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2021-10-15Bibliographically approved
Danvind, J., Eriksson, J. & Johansson, H. (2004). Calibration of a constitutive model for diffuse moisture transport in wood using data from X-ray CT-scanning and digital speckle photography (ed.). Paper presented at International conference of COST Action E15 Wood drying : 21/04/2004 - 22/04/2004. Paper presented at International conference of COST Action E15 Wood drying : 21/04/2004 - 22/04/2004.
Open this publication in new window or tab >>Calibration of a constitutive model for diffuse moisture transport in wood using data from X-ray CT-scanning and digital speckle photography
2004 (English)Conference paper, Oral presentation only (Refereed)
National Category
Bio Materials
Research subject
Wood Physics
Identifiers
urn:nbn:se:ltu:diva-35065 (URN)97297d70-9f24-11dc-9810-000ea68e967b (Local ID)97297d70-9f24-11dc-9810-000ea68e967b (Archive number)97297d70-9f24-11dc-9810-000ea68e967b (OAI)
Conference
International conference of COST Action E15 Wood drying : 21/04/2004 - 22/04/2004
Note
Godkänd; 2004; 20071130 (cira)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2021-10-15Bibliographically approved
Danvind, J. & Morén, T. (2004). Using X-ray CT scanning for moisture and displacement measurements in knots and their surroundings (ed.). Paper presented at International conference of COST Action E15 Wood drying : 21/04/2004 - 22/04/2004. Paper presented at International conference of COST Action E15 Wood drying : 21/04/2004 - 22/04/2004.
Open this publication in new window or tab >>Using X-ray CT scanning for moisture and displacement measurements in knots and their surroundings
2004 (English)Conference paper, Oral presentation only (Refereed)
National Category
Bio Materials
Research subject
Wood Physics
Identifiers
urn:nbn:se:ltu:diva-28272 (URN)20435e70-9f23-11dc-9810-000ea68e967b (Local ID)20435e70-9f23-11dc-9810-000ea68e967b (Archive number)20435e70-9f23-11dc-9810-000ea68e967b (OAI)
Conference
International conference of COST Action E15 Wood drying : 21/04/2004 - 22/04/2004
Note
Godkänd; 2004; 20071130 (cira)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2021-10-15Bibliographically approved
Danvind, J. (2003). Measuring strain and moisture content in a cross section of drying wood using Digital Speckle Photography and Computerised X-ray Tomography (ed.). In: (Ed.), Frank C. Beall (Ed.), Proceedings of the 13th International Symposium on Nondestructive Testing of Wood: August 19-21, 2002, University of California, Berkeley Campus, California, USA. Paper presented at International Symposium on Nondestructive Testing of Wood : 19/08/2002 - 21/08/2002. Madison, Wis.: Forest Products Society
Open this publication in new window or tab >>Measuring strain and moisture content in a cross section of drying wood using Digital Speckle Photography and Computerised X-ray Tomography
2003 (English)In: Proceedings of the 13th International Symposium on Nondestructive Testing of Wood: August 19-21, 2002, University of California, Berkeley Campus, California, USA / [ed] Frank C. Beall, Madison, Wis.: Forest Products Society, 2003Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Madison, Wis.: Forest Products Society, 2003
National Category
Bio Materials
Research subject
Wood Physics
Identifiers
urn:nbn:se:ltu:diva-38185 (URN)c7f7d190-0799-11dc-b09b-000ea68e967b (Local ID)1-892529-31-9 (ISBN)c7f7d190-0799-11dc-b09b-000ea68e967b (Archive number)c7f7d190-0799-11dc-b09b-000ea68e967b (OAI)
Conference
International Symposium on Nondestructive Testing of Wood : 19/08/2002 - 21/08/2002
Note
Godkänd; 2003; 20070521 (cira)Available from: 2016-10-03 Created: 2016-10-03 Last updated: 2021-10-15Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-9205-6807

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