Barbara Ozarska | University of Melbourne (original) (raw)

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Papers by Barbara Ozarska

Polymer Composites, 2023

This study investigated Australian hemp hurd (Cannabis sativa L., “Frog One”) as a lignocellulosi... more This study investigated Australian hemp hurd (Cannabis sativa L., “Frog One”) as a lignocellulosic raw material for ultra‐low‐density hemp particleboard (ULHPB) with densities ranging from 213 to 309 kg/m3. The hurd was first milled and fractionated into three particle size categories, that is, fine (F), medium (M), and coarse (C). Twelve unique ULHPB variants were then fabricated comprising varying particle loadings from four particle size mixes, that is, 100% C, 100% M, 50%/50% CM, 25%/50%/25% CMF, and adhesive contents of bio‐epoxy (EPX), phenol resorcinol formaldehyde (PRF), and emulsifiable methylene diphenyl diisocyanate (MDI), respectively. The panel assessments, conducted in accordance with the Australian reconstituted wood‐based panels standard AS/NZS 1859.1 (2017), revealed a significant effect of particle dimension on most physico‐mechanical properties. Furthermore, the resination method and pressing temperature controlled post‐cure panel expansion and additional panel ch...

Maderas-Cienc Tecnol

Papua New Guinea (PNG) has abundant natural forest resources but there are many constraints which... more Papua New Guinea (PNG) has abundant natural forest resources but there are many constraints which need to be addressed to support the development of competitive value-added wood industries. There is a need to develop knowledge and capacity in wood science and processing technologies which support successful domestic value-adding wood processing enterprises. A comprehensive testing program has been developed to assess the glue‐bond strength and performance of selected commercial PNG timber species in various climatic conditions to simulate service conditions in potential market destinations. Two criteria namely shear strength and wood failure have been used to determine if a species can meet the minimum requirements for either dry use or wet use applications. The performance of 24 different PNG commercial timber species has been assessed using a one-component cross-linking polyvinyl acetate emulsion adhesive. The bondability of the selected species has been carefully estimated consid...

Forests, 2022

The recent legalisation of hemp seeds for human consumption has revitalised the cultivation of he... more The recent legalisation of hemp seeds for human consumption has revitalised the cultivation of hemp in Australia. This provides opportunities for the valorisation of the stem’s residual xylemic core (hemp hurd). This study investigated the effect of particle dimension and constituent proportions on the internal bond strength (IB) of single-layer, ultra-low-density hemp hurd particleboard (ULHPB) with densities between 219 to 304 kg/m3. Particle size distributions (PSD) and granulometry assessments were conducted on three particle size classes (fine (F), medium (M), coarse (C)) based on digital image analysis using ImageJ. Subsequently, four particle size mixes (100% C, 100% M, 50/50% CM, 25/50/25% CMF) were considered for the ULHPB manufacture with bio-epoxy (EPX), phenol resorcinol formaldehyde (PRF) and emulsifiable methylene diphenyl diisocyanate (MDI) adhesives, respectively. The effect of particle loading and adhesive content varied significantly per adhesive type. Internal bon...

Industrial Crops and Products, 2024

This study investigated the feasibility of using citric acid (CA) as a biobased and formaldehyde-... more This study investigated the feasibility of using citric acid (CA) as a biobased and formaldehyde-free binder for producing ultra-low-density (320 to 338 kg/m 3) hemp hurd particleboard (ULHPB). Mechanically decorticated hemp hurd chips were milled and then separated into fine (F), medium (M), and coarse (C) particle sizes. Three particle size mixes (PSM) were used to fabricate the panels: 100% C, 100% M, and a 50/50% mixture of CM. Each PSM was combined with low and high CA contents (20 and 30 wt%) and subjected to short and long pressing times (8 and 12 min) at 200 • C. Physico-mechanical characteristics were evaluated following Australian standard AS/ NZS 1859.1 (2017) for reconstituted wood-based panels. Thermo-chemical analyses were performed to understand the properties of the raw hurd and to investigate the binding mechanisms in CA-ULHPB. The PSM had a significant impact on panel expansion (springback), internal bond strength (IB), water absorption (WA), and thickness swelling (TS) in most CA-ULHPB variants. PSM-C panels exhibited superior IB when pressed with 30 wt % CA for 12 min. The effect of PSMs diminished for WA and TS but CA content and pressing time remained highly significant. Py-GC/MS, FTIR spectroscopy and TGA indicated the formation of ester linkages with carbohydrate-derived OH-groups and the involvement of lignin moieties in the CA-ULHPB. This research identified optimal panel compositions and processing parameters for fabricating environmentally friendly composite panels using CA as a natural adhesive and hemp hurd as an agricultural by-product. The panels exhibited excellent properties and would be well suited as core layers in lightweight sandwich composites given their ultralow-density range.

Zenodo (CERN European Organization for Nuclear Research), Oct 1, 2020

Bioresources, Jul 11, 2018

International Forestry Review, Dec 1, 2009

Forests

ILFR Postgraduate Conference, 2004

IUFRO 2017 Division 5 Conference & SWST 60th International Convention, 2017

The wood welding potential of three commercial Australian hardwood species has been investigated ... more The wood welding potential of three commercial Australian hardwood species has been investigated with the aim of bringing this fast assembling technique to an efficient manufacturing process for the production of high-value wood products. Optimal linear and rotational wood welding parameters were determined for Eucalyptus saligna, Eucalyptus pilularis and Corymbia maculata and different joining methods. The optimized parameters for each selected species and welding process were determined using an adapted tensile or shear strength test. The results confirmed the importance of density in the optimization process where the grain direction proved to have a significant impact on the welded joint strength. Some other anatomical features also showed to affect the mechanical properties of the welded joints. Energy consumption measurements provided useful information while appearing as an interesting non-destructive method to assess the weldline quality. Limiting factors which could have implications for future commercial applications have also been identified as part of the present study. Overall, wood welding of Australian hardwood species could be a suitable alternative for non-structural indoor applications where gluing is usually required

International Forestry Review, 2005

This study extends the knowledge of acoustic absorption properties of Papua New Guinea (PNG) bals... more This study extends the knowledge of acoustic absorption properties of Papua New Guinea (PNG) balsa in three experimental stages for architectural applications in the built environment to improve the wellness of occupants. Stage one tested balsa as a stand-alone material in impedance tubes according to ISO 10534-2. The results indicated PNG balsa has low absorption properties across 100 to 5000 Hz in 1/3rd Octave-band centre frequencies. The largest arithmetic average of alpha (αSTAT) calculated was 0.20 from testing 25 mm thick end-grain balsa with a measured density of 87.5 kg/m3 (average of three discrete samples) and the lowest 0.05 from testing 50 mm thick perpendicular-grain balsa with a measured density of 112.5 kg/m3. Stage two tested balsa composite panels in a reverberation chamber according to AS ISO 354 and AS ISO 11654. The results highlighted the noise reduction coefficient and weighted sound absorption coefficient of two differently laminated composite panels was 0.75 ...

Most efficiency improvement strategies implemented in furniture manufacturing are data-driven met... more Most efficiency improvement strategies implemented in furniture manufacturing are data-driven methods. Due to a lack of production systems used in most Indonesian small and medium-sized furniture companies, the evaluation of production efficiency for future improvement seems rather difficult to perform. A wide range of existing evaluation tools and the varying capabilities of the companies to adapt the methods contribute to a problematic evaluation process. Research has been undertaken with the aim to develop a generic efficiency evaluation method and to prioritise a new potential metric to assess and control efficiency in furniture manufacturing. A basic production cost analysis with standardized variables has been demonstrated as a typical method to evaluate production efficiency in multi furniture companies, followed by applying a wood recovery assessment, a Pareto analysis, an X-Y matrix, and process capability analysis. The heartwood proportion of teak (Tectona grandis) has bee...

Polymer Composites, 2023

Maderas-Cienc Tecnol

Forests, 2022

Industrial Crops and Products, 2024

Zenodo (CERN European Organization for Nuclear Research), Oct 1, 2020

Bioresources, Jul 11, 2018

International Forestry Review, Dec 1, 2009

Forests

ILFR Postgraduate Conference, 2004

IUFRO 2017 Division 5 Conference & SWST 60th International Convention, 2017

International Forestry Review, 2005

This study assessed the moulding, drilling, turning, sanding, and routing properties of seven pla... more This study assessed the moulding, drilling, turning, sanding, and routing properties of seven plantation-grown hardwood species from southeast Australia to evaluate their potential as a resource for the manufacture of high quality furniture and furnishings. Eucalyptus grandis, Eucalyptus saligna, Corymbia maculata, Eucalyptus camaldulensis, Eucalyptus sideroxylon, Eucalyptus cladocalyx, and Eucalyptus globulus were machined using different tools, and the surface quality obtained was visually graded. A sanding sequence of 100-150 grit produced satisfactory surfaces for furniture manufacturing for most studied species. Usually, a feeding direction against the rotational direction of the tool showed best results and reduced incidence of corner breakout when routing. Overall, high-density plantation-grown Australian hardwood species performed well during machining trials with the use of appropriate parameters and cutting tools allowing overcoming some typical processing difficulties for some species. The data obtained within this study will allow optimising the machining process of plantation-grown wood in Australia and increase value from the current plantation resource.

A comprehensive testing program has been developed to assess different physical and mechanical pr... more A comprehensive testing program has been developed to assess different physical and mechanical properties of 26 commercial and lesser-known Papua New Guinea species from secondary and plantation forests. The impact of log position in a tree on the mechanical properties has also been assessed to optimize the utilization of timbers along the value chain. The results showed that stiffness and bending strength tend to decrease or remain unchanged along the stem. Shear strength and Janka hardness displayed a similar trend to a lesser extent where the position in the tree had a limited impact on compression strength properties. Thus, segregating based on log position can be of interest where desired mechanical properties and costs associated with segregating justify optimum mechanical properties for the intended end use. The properties of selected species from plantations and regrowth forests were generally lower than those found in the literature for timbers from old-growth forests. The size of specimens tested, the amount and provenance of tested material, and some adaptive traits for tropical tree species are some factors potentially explaining observed differences. However, a comparison with recent studies tends to confirm the overall reduction of physical and mechanical properties when compared with old-growth forests timbers.