| 1. |
- Garskaite, Edita, et al.
(författare)
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Studying the application of fish-farming net-cleaning waste as fire-retardant for Scots pine (Pinus sylvestris L.) sapwood
- 2022
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Ingår i: EFB Bioeconomy Journal. - : Elsevier. - 2667-0410. ; 2
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Tidskriftsartikel (refereegranskat)abstract
- Optimising the exploitation of available waste resources for the recovery of their intrinsic value will be vital in the future circular economy society. Recovery of energy, nutrients and metals from waste streams is in focus today. This study aimed to evaluate the use of an aquaculture waste, i.e. the dried-solid waste discharge that generates by cleaning the fishing-nets, as a potential fire-retardancy promoter for Scots pine sapwood. As-received dried-solid waste from salmon-farming was calcined at different temperatures to evaluate material phase transformation and achieve homogeneous phase distribution. Thermal degradation of waste powders was studied by TG-FTIR gas analysis when annealing the material to temperatures up to 800°C, and the crystallinity, phase composition, morphology, elemental composition and particle sizes of as-received and calcined-waste materials at different temperatures were evaluated by XRD, FTIR, SEM/EDS, and TEM analyses. The flammability studies using cone calorimeter of Scots pine sapwood blocks treated with as-received and processed material is also reported and discussed. Results were promising, indicating that the aquaculture waste could be employed as an effective fire-retardant. The possibility of value-creation from waste discharges is enforced in this study so to promote the way towards waste valorisation and circular economy.
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| 2. |
- Garskaite, Edita, et al.
(författare)
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Surface hardness and flammability of Na2SiO3 and nano-TiO2 reinforced wood composites
- 2019
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Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 9:48, s. 27973-27986
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this study was to explore an effect of the combined inorganic materials on the wood hardness and flame-retardancy properties in a concept of sustainable material management. Herein, the reinforcement of Scots pine (Pinus sylvestris L.) sapwood with sodium silicate and TiO2 nanoparticles via vacuum-pressure technique is reported. Pyrolysis of modified wood was studied by TG-FTIR analysis; the results showed that maximum weight loss for the modified wood was obtained at 40–50 °C lower temperatures compared to the reference untreated wood. The Gram–Schmidt profiles and spectra extracted at maxima absorption from Gram–Schmidt plots indicated chemical changes in wood–inorganic composites. SEM/EDS analysis revealed the presence of Na–O–Si solid gel within the wood-cell lumen and showed that TiO2 was homogeneously distributed within the amorphous Na–O–Si glass-forming phase to form a thin surface coating. EDS mapping further revealed the higher diffusivity of sodium into the cell wall compared to the silicon compound. The presence of amorphous sodium silicate and nano-TiO2 was additionally confirmed by XRD analysis. FTIR spectra confirmed the chemical changes in Scots pine sapwood induced by alkalization. Brinell hardness test showed that the hardness of the modified wood increased with the highest value (44% increase in hardness) obtained for 10% Na2SiO3–nTiO2 modified wood. The results showed good correlation between TG and flammability test; limiting oxygen index (LOI) values for the wood–inorganic composites increased by 9–14% compared to the untreated wood.
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| 3. |
- Garskaite, Edita, et al.
(författare)
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The Accessibility of the Cell Wall in Scots Pine (Pinus sylvestris L.) Sapwood to Colloidal Fe3O4 Nanoparticles
- 2021
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Ingår i: ACS Omega. - : American Chemical Society (ACS). - 2470-1343. ; 6:33, s. 21719-21729
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Tidskriftsartikel (refereegranskat)abstract
- This work presents a rapid and facile way to access the cell wall of wood with magnetic nanoparticles (NPs), providing insights into a method of wood modification to prepare hybrid bio-based functional materials. Diffusion-driven infiltration into Scots pine (Pinus sylvestris L.) sapwood was achieved using colloidal Fe3O4 nanoparticles. Optical microscopy, scanning electron microscopy/energy-dispersive X-ray spectroscopy, transmission electron microscopy, and X-ray powder diffraction analyses were used to detect and assess the accessibility of the cell wall to Fe3O4. The structural changes, filling of tracheids (cell lumina), and NP infiltration depth were further evaluated by performing X-ray microcomputed tomography analysis. Fourier transform infrared spectroscopy was used to assess the chemical changes in Scots pine induced by the interaction of the wood with the solvent. The thermal stability of Fe3O4-modified wood was studied by thermogravimetric analysis. Successful infiltration of the Fe3O4 NPs was confirmed by measuring the magnetic properties of cross-sectioned layers of the modified wood. The results indicate the feasibility of creating multiple functionalities that may lead to many future applications, including structural nanomaterials with desirable thermal properties, magnetic devices, and sensors.
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| 4. |
- Golubevas, Ricardas, et al.
(författare)
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Acrylate–gelatin–carbonated hydroxyapatite (cHAP) composites for dental bone-tissue applications
- 2020
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Ingår i: Materials Advances. - : Royal Society of Chemistry. - 2633-5409. ; 1:6, s. 1675-1684
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Tidskriftsartikel (refereegranskat)abstract
- Various types of scaffolds made of synthetic polymers have been widely studied for bone-tissue applications due to their mechanical strength, biocompatibility and biodegradability, but the hydrophobic nature of synthetic polymers and frequent absence of pores within the scaffolds inhibit cellular attachment, infiltration, and tissue ingrowth. In this study, multi-composite scaffolds composed of dipentaerythritol hexa-acrylate (DPHA), ethylene glycol dimethacrylate (EGDMA), gelatin, and carbonated hydroxyapatite (cHAP) have been made. Percentage ratio of polymer matrix to gelatin was varied 50/50, 75/25, and 95/5 to change the porosity of the resultant scaffolds. The structure, crystallinity, and phase composition of the cHAP were confirmed by FTIR, Raman, XRD and Rietveld analyses, TG/DSC was used to evaluate the distribution of ceramics within the polymer matrix, and FTIR-ATR was used to confirm the molecular structure of composites. SEM/EDS analysis of the scaffolds revealed cavities and irregularities in the surface, and that cHAP was indistinctly exposed on the composite surface, computed tomography (CT) was used to estimate the density and homogeneity of the scaffolds, and the cHAP distribution within the scaffolds was evaluated by conventional radiography. The hydrophilicity of the multi-composite scaffolds was investigated using an aqueous solution of methylene blue dye which showed that the acrylate(75%)–gelatin(25%)–cHAP composite had the highest hydrophilicity. The results suggest that acrylate–gelatin–cHAP scaffolds have a potential for bone-tissue engineering.
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| 5. |
- Grazenaite, Egle, et al.
(författare)
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Ga-Substituted Cobalt-Chromium Spinels as Ceramic Pigments Produced by Sol–Gel Synthesis
- 2020
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Ingår i: Crystals. - : MDPI. - 2073-4352. ; 10:12
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Tidskriftsartikel (refereegranskat)abstract
- For the first time to the best of our knowledge, cobalt-chromium spinels CoCr2−xGaxO4 with different amounts of gallium (x = 0–2 with a step of 0.5) were synthesized via the aqueous sol–gel route as ceramic pigments. The phase composition, crystallite size, morphological features, and color parameters of new compositions and their corresponding ceramic glazes were investigated using XRD, CIELab, SEM, and optical microscopy. It was demonstrated that the formation of single-phase CoCr2−xGaxO4 samples was problematic. Full substitution of Cr3+ by Ga3+ ion in the spinel resulted in the formation of light blue powders, which yielded violetish blue color for the corresponding ceramic glaze.
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