Evaluation of wooden materials deteriorated by marine wood boring organisms in the black sea

Marine borers can destroy wooden structures exposed to the marine environment and cause great monetary loss. In the region of Amasra of the Black Sea in Turkey, ships continue to be built from wood, mainly Castanea sativa (sweet chestnut) and Quercus petraea (sessile oak) and therefore are subject to destruction by marine borers. Copper-chromium-arsenic (CCA), used to be one of the most common wood preservatives used    in Turkey. However, in this area its efficacy against mari-ne borers is unknown.   The resistance of untreated and CCA-treated samples of chestnut, oak and Scots pine (Pinus sylvestris) was examined  and aft er twelve months evaluated in two ways, EN 275, and a non-destructive measurement for dynamic modulus of elasticity (MOE). Untreated samples, particularly Scots pine were severely attacked by Teredo navalis. Treated samples of oak and chestnut were moderately attacked while treated samples of Scots pine sapwood and heartwood were sound. Severity of wood boring attack determined using MOE showed a very good correlation with that de-termined by visual assessment in untreated wood, and a good correlation for treated wood. Dynamic MOE allows rapid on-site evaluation rather than measurements within a laboratory and also without causing damage to the structures being evaluated

Plasticity in dendroclimatic response across the distribution range of Aleppo pine (Pinus halepensis)

We investigated the variability of the climate-growth relationship of Aleppo pine across its distribution range in the Mediterranean Basin. We constructed a network of tree-ring index chronologies from 63 sites across the region. Correlation function analysis identified the relationships of tree-ring index to climate factors for each site. We also estimated the dominant climatic gradients of the region using principal component analysis of monthly, seasonal, and annual mean temperature and total precipitation from 1,068 climatic gridpoints. Variation in ring width index was primarily related to precipitation and secondarily to temperature. However, we found that the dendroclimatic relationship depended on the position of the site along the climatic gradient. In the southern part of the distribution range, where temperature was generally higher and precipitation lower than the regional average, reduced growth was also associated with warm and dry conditions. In the northern part, where the average temperature was lower and the precipitation more abundant than the regional average, reduced growth was associated with cool conditions. Thus, our study highlights the substantial plasticity of Aleppo pine in response to different climatic conditions. These results do not resolve the source of response variability as being due to either genetic variation in provenance, to phenotypic plasticity, or a combination of factors. However, as current growth responses to inter-annual climate variability vary spatially across existing climate gradients, future climate-growth relationships will also likely be determined by differential adaptation and/or acclimation responses to spatial climatic variation. The contribution of local adaptation and/or phenotypic plasticity across populations to the persistence of species under global warming could be decisive for prediction of climate change impacts across populations. In this sense, a more complex forest dynamics modeling approach that includes the contribution of genetic variation and phenotypic plasticity can improve the reliability of the ecological inferences derived from the climate-growth relationships.This work was partially supported by Spanish Ministry of Education and Science co-funded by FEDER program (CGL2012-31668), the European Union and the National Ministry of Education and Religion of Greece (EPEAEK- Environment – Archimedes), the Slovenian Research Agency (program P4-0015), and the USDA Forest Service. The cooperation among international partners was supported by the COST Action FP1106, STREeSS

ALTERNATIVE BINDERS TO BENTONITE FOR IRON ORE PELLETIZING : PART II : EFFECTS ON METALLURGICAL AND CHEMICAL PROPERTIES

This study was started to find alternative binders to bentonite and to recover the low preheated and fired pellet mechanical strengths of organic binders-bonded pellets. Bentonite is considered as a chemical impurity for pellet chemistry due to acid constituents (SiO2 and Al2O3). Especially addition of silica-alumina bearing binders is detrimental for iron ore concentrate with high acidic content. Organic binders are the most studied binders since they are free in silica. Although they yield pellets with good wet strength; they have found limited application in industry since they fail to give sufficient physical and mechanical strength to preheated and fired pellets. It is investigated that how insufficient preheated and fired pellet strengths can be improved when organic binders are used as binder. The addition of a slag bonding/strength increasing constituent (free in acidic contents) into pellet feed to provide pellet strength with the use of organic binders was proposed. Addition of boron compounds such as colemanite, tincal, borax pentahydrate, boric acid together with organic binders such as CMC, starch, dextrin and some organic based binders, into magnetite and hematite pellet mixture was tested. After determining the addition of boron compounds is beneficial to recover the low pellet physical and mechanical qualities in the first part of this study, in this second part, metallurgical and chemical properties (reducibility - swelling index – microstructure – mineralogy - chemical content) of pellets produced with combined binders (an organic binder plus a boron compound) were presented. The metallurgical and chemical tests results showed that good quality product pellets can be produced with combined binders when compared with the bentonite-bonded pellets. Hence, the suggested combined binders can be used as binder in place of bentonite in iron ore pelletizing without compromising the pellet chemistry

Dimensional stabilization of wood treated with tall oil dissolved in different solvents

Many water repellents, such as classic wood preservatives have the disadvantage of being harmful to the environment. Therefore, interest increased even eco-friendly, or of biodegradable material. Natural oils (tallow, linseed oil), appears to be capable of preventing the wood water uptake. However, the total amount of oil required to achieve a high penetration of the sapwood. The aim of this study was to investigate the water repellent efficiency of tall oil dissolved in different solvents. As solvents ethanol, methanol, acetone and tall oil water emulsions were used. Scots pine and Uludag fir sapwood samples were impregnated with tall oil formulations. For this purpose we used tall oil/solvents (W/W) at the concentrations of 10% and 20% respectively. Test samples cut into small sizes (20 × 20 × 10 ± 0,2 mm) for water uptake and tangential swelling tests. The tests were carried out based on American Wood Protection Association (AWPA) standard E4 (2003)

Effect of weathering on wood treated with tall oil combined with some additives

Growing interest on bio-based material has led to focus on environmentally benign wood treatment systems because of the environmental concerns. Tall oil is a by-product from pulp and paper industry, contains resin and fatty acids, and is biodegradable. Tall oil treated wood can provide some reduction in water uptake and increase in decay resistance. In this research crude tall oil was dissolved in ethanol at 5, 10 and 15 % concentrations in the treatment of Scots pine according to full cell process. Dyestuff, iron oxide and sodium ascorbate were used an additive as 0,5 %. Weathering performance of tall oil and tall oil combined with additives were investigated in accelerated weathering chamber by application of ultraviolet irradiation and water spray. It is taken for granted that increasing concentration results in higher weight percent gain in treated samples. The best results were obtained with 10 % tall oil and iron oxide which indicated minimum total color changes. Colour measurements and visual examination revealed that iron oxide was the most effective additive in reducing weathering effect and lowering the total colour change

ALTERNATIVE BINDERS TO BENTONITE FOR IRON ORE PELLETIZING: PART I: EFFECTS ON PHYSICAL AND MECHANICAL PROPERTIES

The use of conventional bentonite binder is favorable in terms of mechanical and metallurgical pellet properties, however, because of its acid constituents bentonite is considered as impurity especially for iron ores with high acidic content. Therefore, alternative binders to bentonite have been tested. Organic binders are the most studied binders and they yield pellets with good wet strength; they fail in terms of preheated and fired pellet strengths. This study was conducted to investigate how insufficient pellet strengths can be improved when organic binders are used as binder. The addition of a low-melting temperature and slag bonding/strength increasing constituent (free in acidic contents) into pellet feed was proposed. Addition of boron compounds such as colemanite, tincal, borax pentahydrate, boric acid together with organic binders such as CMC, starch, dextrin and some organic based binders, into iron oxide pellet was tested. Wet and thermally treated pellet physical-mechanical qualities (balling - moisture content - size - shape - drop number - compressive strengths - porosity - dustiness) were determined. The results showed that good quality wet, dry, preheated and fired pellets can be produced with combined binders (an organic binder plus a boron compound) when compared with bentonite-bonded pellets. While organic binders provided sufficient wet and dry pellet strengths, the boron compounds provided the required preheated and fired pellet strengths at even lower firing temperature. Especially, the contribution of boron compound addition is most pronounced for hematite pellets which do not have strengthening mechanism through oxidation like magnetite pellets during firing. Therefore, addition of boron compound is beneficial to recover the low physical-mechanical qualities of pellets produced with organic binders through slag bonding mechanism. Furthermore, lowering the firing temperature thanks to low-melting boron compounds will be cost-effective for firing part of the pelletizing plants

Surface characterization of some woods exposed to accelerated weathering

28th International Conference on Wood Science and Technology 2017: Implementation of Wood Science in Woodworking Sector, ICWST 2017 -- 7 December 2017 through 8 December 2017 -- -- 133147In this study, the photo degradation of beech (Fagus orientalis), oak (Quercus robur), ash (Fraxinus spp.), and poplar (Populus euramericana) wood samples were investigated by accelerated weathering test in order to determine the chemical change by Attenuated total reflectance-Fourier transform infrared (ATR-FTIR), surface degradation by Scanning Electron Microscopy (SEM) and colour measurements by portable spectrophotometer. For this purpose, weathering of wood samples was performed in an accelerated weathering tester using ultraviolet irradiation with 0.85 W/m2 at 340 nm for 1000 h. According to results after 168 hours of weathering, the exposed samples showed considerable change in colour, which accompanied with the chemical change in wood components. After that time the total colour change showed a decrease. During the remaining time in weathering process total colour change lowered in comparison to 168 hours. Overall, the highest colour change was obtained with ash samples after weathering. SEM analyses showed cracks on the surface of the wood samples exposed to 1000 hours of weathering