Thermal Conductivity of Papua New Guinea Balsa Wood Measured using the Needle Probe Procedure

Kotlarewski, N; Ozarska, Barbara; Gusamo, Benson K.

doi:10.15376/biores.9.4.5784-5793

Cited by 23 publications

(12 citation statements)

References 8 publications

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“…This yielded slightly higher thermal conductivities of to on the perpendicular direction to the pore major axis and on the parallel direction to the pore axis. This reveals that the material is better at insulating than felt (thermal conductivity ) or wood such as the low-density balsa, which has a thermal conductivity ranging from to 40 .…”

Section: Resultsmentioning

confidence: 99%

Scalable method for bio-based solid foams that mimic wood

Reichler

Rabensteiner

Törnblom

et al. 2021

Sci Rep

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Mimicking natural structures allows the exploitation of proven design concepts for advanced material solutions. Here, our inspiration comes from the anisotropic closed cell structure of wood. The bubbles in our fiber reinforced foam are elongated using temperature dependent viscosity of methylcellulose and constricted drying. The oriented structures lead to high yield stress in the primary direction; 64 times larger than compared to the cross direction. The closed cells of the foam also result in excellent thermal insulation. The proposed novel foam manufacturing process is trivial to up-scale from the laboratory trial scale towards production volumes on industrial scales.

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Section: Resultsmentioning

confidence: 99%

Scalable method for bio-based solid foams that mimic wood

Reichler

Rabensteiner

Törnblom

et al. 2021

Sci Rep

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“…Kotlarewski (2016) explored the systematic development of a novel and commercial balsa woodbased products. This work included determining the commercially important properties of PNG plantation-grown balsa wood, viz, static bending, hardness (Janka), compression parallel to the grain, compression perpendicular to the grain and shear parallel to the grain ; and its thermal properties (Kotlarewski et al 2014). Both sets of data underpinned the development of a novel balsa wall panel product, which itself was recognised with a design award (Swinburne University 2015; Kotlarewski 2016).…”

Section: Processing and Productsmentioning

confidence: 99%

Improving the smallholder balsa value chain in East New Britain Province, Papua New Guinea

Jenkin¹,

Minimulu

Kanowski

2018

Australian Forestry

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Ochroma pyramidale (balsa) is a fast-growing tree, grown as a plantation crop by both companies and smallholders in East New Britain Province (ENB) of Papua New Guinea (PNG). The ENB balsa industry is entirely export-oriented, producing 9% of the world's processed balsa. Balsa products have outstanding strength-for-weight qualities and an increasing market in high-technology composite materials, such as wind turbine blades and transportation applications. Ochroma pyramidale is attractive to smallholders because it is a relatively low labour-input crop with competitive returns and a relatively short (5-6 years) harvest cycle. There are c. 6200 ha of balsa plantations in ENB, including c. 1900 ha grown and managed by c. 1500 individual smallholder farmers. A workforce of some 2500-3000 is engaged in balsa harvest, transport, processing and export in ENB. These activities operate under the regulatory oversight of the PNG Forest Authority, which also plays an 'honest broker' role in transactions between processing companies and smallholders. The major challenges faced by the ENB balsa industry relate to balsa plantation productivity and sustainability, market access in the context of forest certification and legality verification, and product development and diversification. This paper reports outcomes of a research project supported by the Australian Centre for International Agricultural Research, in which Australian and PNG researchers worked with the ENB balsa industry to address these challenges. The project conducted balsa sector surveys and silvicultural experiments, introduced and tested genetic resources, and undertook both knowledge and product development for the industry. Key research outcomes included the development of a 'smallholder friendly' silvicultural regime that obviates the need for thinning or refilling, and should deliver greater merchantable volume and value recovery for growers; an updated Balsa Manual from which smallholder learning resources were developed and integrated into an established ENB agricultural training program; confirmation that harvesting recovery from smallholder plantations was consistent with log quality requirements, and that harvesting and transport activities were operating efficiently; and the development of new balsa panel products particularly suited to apartment interiors. Research also facilitated the adoption of certification in the ENB balsa sector, and identified targeted regulatory reform as desirable to support the continuing development of the ENB balsa industry. ARTICLE HISTORY

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“…There are several approaches to measuring thermal properties (guarded hot plate and heat flow meter methods, transient hot-strip methods, transient heat methods, laser flash methods, hot disk sensor methods, steady-state methods), depending primarily on the material under test and its intended application [12]. This can be seen, for example, in the standards ASTM D5334-08, ASTM C1113/C1113M-09(2019), ISO 8301:1991 and ISO 8302:1991, ISO 22007-2:2015, JIS R 1611:1997, ČSN EN 12664 and ČSN EN 12667 [13,14], with the information in the papers dealing with this issue found in the literature [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32]. Research dating back about 100 years or more [33][34][35] and the fundamental classical literature of thermal physics [36][37][38] can be considered the basis for this.…”

Section: Introductionmentioning

confidence: 99%

Haptic and Aesthetic Properties of Heat-Treated Modified Birch Wood

Borůvka

Šedivka

Novák

et al. 2021

Forests

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This paper deals with the effect of heat treatment on the selected physical properties of birch wood. Five stages of heat treatment were used, ranging from 160 °C to 200 °C, in 10 °C increments, having a peak treatment duration of 3 h for each level. Primarily, changes in thermal characteristics, namely conductivity, diffusivity, effusivity, volume heat capacity, changes in colour and gloss parameters, mass loss due to modification and different moisture content in wood under given equilibrium climatic conditions, were monitored. The ISOMET 2114 analyser was used to measure the thermal characteristics. The measurement principle of this analyser is based on the analysis of the thermal response of the analysed material to pulses of heat flow. Measurements of colour, gloss, density and moisture content were carried out according to harmonised EN standards. The aim was to experimentally verify the more or less generally known more positive perception of heat-treated wood, both by touch and sight, i.e., the warmer perception of darker brown shades of wood. In terms of thermal characteristics, the most interesting result is that they gradually decrease with increasing treatment temperature. For example, at the highest treatment temperature of 200 °C, there is a decrease in thermal conductivity by 20.2%, a decrease in volume heat capacity by 15.0%, and a decrease in effusivity by 17.7%. The decrease in thermal conductivity is nearly constant at all treatment levels, specifically at this treatment temperature, by 6.0%. The fact mentioned above is positive in terms of the tactile perception of such treated wood, which can have a positive effect, for example, in furniture with surface application of heat-treated veneers, which are perceived positively by the majority of the human population visually or as a cladding material in saunas. In this context, it has been found that the thermal modification at the above-mentioned treatment temperature of 200 °C results in a decrease in brightness by 44.0%, a decrease in total colour difference by 38.4%, and a decrease in gloss (at an angle of 60°) by 18.2%. The decrease in gloss is only one essential negative aspect that can be addressed by subsequent surface treatment. During the heat treatment, there is also a loss of mass in volume, e.g., at a treatment temperature of 200 °C and subsequent conditioning to an equilibrium moisture content in a conditioning chamber with an air temperature of 20 ± 2 °C and relative humidity of 65 % ± 5%, there was a decrease by 7.9%. In conclusion, the experiments clearly confirmed the hypothesis of a positive perception of heat-treated wood in terms of haptics and aesthetics.

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Thermal Conductivity of Papua New Guinea Balsa Wood Measured using the Needle Probe Procedure

Cited by 23 publications

References 8 publications

Scalable method for bio-based solid foams that mimic wood

Scalable method for bio-based solid foams that mimic wood

Improving the smallholder balsa value chain in East New Britain Province, Papua New Guinea

Haptic and Aesthetic Properties of Heat-Treated Modified Birch Wood

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