Reducing fuzziness in abrasive sanding of rubberwood (Hevea brasiliensis)

Rubberwood (Hevea brasiliensis) is the predominant wood raw material for the furniture industry in South East Asia. However, the prevalence of surface fuzziness after the abrasive sanding process contributes towards the low processing yield. In an effort to reduce the manifestation of surface fuzziness, a series of experiments was carried out in the laboratory using a cross-head wide-belt sander. The results showed that the sanding grit 120 on the cross-head, followed by sanding grits 150 and 180 produced the best surface quality

Characterizing surface defects in machine-planning of rubberwood (Hevea brasiliensis)

Despite its extensive application in the furniture manufacturing industry throughout the South East Asian region, the machine-planing characteristics of rubberwood (Hevea brasiliensis) are not completely understood. In an effort to optimize the process, a series of experiments were undertaken using a Weinig 22A Unimat moulder (cutter-head rpm of 6000, cutter Ø 120 mm) to produce machined rubberwood surfaces with differing pitch lengths ranging from 0.8 mm to 1.5 mm, by altering the feed speed. The results showed that surfaces with a pitch length of cutter marks of 1.2 mm or more and a high knife rake angle were more prone to manifest machining defects, such as torn grain. This study shows that for machine planing of rubberwood the recommended cutter marks pitch length of 1.2 mm, achieved with a knife rake angle of 20°, will ensure the highest resultant surface quality and processing yield

Optimization of finger-jointing in rubberwood processing

The study evaluated the finger-jointing configuration of furniture-grade Rubberwood (Hevea brasiliensis) lumber. It was found that fingers of 15 mm in length using PVAc adhesive produced optimum results in terms of bending strength and process economics. Furthermore, finger jointing contributes to yield improvement in Rubberwood processing and will continue to be widely used in the Rubberwood furniture manufacturing industry

Minimizing dust emission during routing operation of rubberwood

The study evaluated airborne dust emission (0.1-10 μm) during the routing operation of Rubberwood (Hevea brasiliensis) in the furniture industry in South East Asia. It was found that the average chip thickness of 0.1 mm and wood moisture content of 12-14% minimized dust emission, while the cutting tool rake angle had little influence on dust emission. The study shows that adverse economic implications due to health hazards posed by airborne dust emissions during wood machining can be reduced by manipulating the average chip thickness and work-piece moisture content

Effects of pre-steaming on the drying quality of rubberwood

In this study, the kiln drying yield of 30 mm Rubberwood (Hevea brasiliensis) furniture stocks with pre-steaming treatment was evaluated. The results revealed that pre-steaming increased the permeability of the wood, hence increasing the drying rate while reducing drying defects. It was found that the pre-steaming treatment should be included in the drying of Rubberwood in order to reduce the overall drying costs as well as improving its quality

Mjerenje sila rezanja piezoelektričnim dinamometrom tijekom piljenja drva tračnom pilom

Optimization of wood cutting conditions can decrease the cutting forces, which directly relates to the energy consumption. The aim of this study was to measure cutting force components in bandsaw processing of green oak and beech wood at 90°-90° cutting direction (mode A). For this purpose, a piezoelectric dynamometer (KISTLER type 9257A) mounted on the log carriage of vertical bandsaw machine (ESTERER model EB 1400) was used to measure the parallel, normal and lateral cutting forces for different cutting speeds (20, 30 and 40 m s-1) and feed rates (20, 30 and 40 m min-1 ). Results showed that all cutting force components change by increasing the cutting speed and feed rate over the analysed range. However, little changes were observed for lateral force. Overall, oak wood required greater cutting forces compared to beech wood. Conclusively, in the studied range,with increasing cutting speed ratio to feed rate, main cutting force and normal force were decreased.Optimizacijom uvjeta rezanja drva mogu se smanjiti sile rezanja čija veličina izravno utječe na potrošnju energije tijekom piljenja. Cilj istraživanja bio je odrediti sastavnice sile rezanja tijekom piljenja svježe hrastovine i bukovine tračnom pilom, uz smjer rezanja 90° - 90° (mod A). U tu svrhu piezoelektrični je dinamometar (Kistler tip 9257A) montiran na posmična kolica za trupce vertikalne tračne pile (ESTERER model EB 1400) i upotrijebljen za mjerenje paralelne, okomite i bočne sile rezanja pri različitim brzinama rezanja (20, 30 i 40 m·s-1) i posmičnim brzinama (20, 30 i 40 m·min-1). Rezultati su pokazali da se sve sastavnice sile rezanja mijenjaju s povećanjem brzine rezanja i posmične brzine u istraživanom rasponu. Male promjene zabilježene su za bočnu silu. Rezultati su pokazali da su za piljenje hrastovine potrebne veće sile rezanja nego pri piljenju bukovine. Zaključno, u promatranom se rasponu brzina s povećanjem omjera brzine rezanja i posmične brzine smanjuju glavna i okomita sastavnica sile rezanja

Surface generation and assessment for peripheral milling

The rotating tool during peripheral milling filters disturbing vibrations between half of the rotation frequency and frequencies assigned to half the time necessary to generate a single cuttermark. This is a relatively large gap in the frequency range being not copied onto the finished surface. Roughness readings returning frequencies in that range are caused by other reasons like secondary fracture effects or the internal structure of the material. Superposition of vibrations at frequencies close to the rotation frequencies may cause interference patterns looking similar to the lines of cuttermarks but without representing the rotating frequency or the frequency of the disturbing vibration. This can also happen for perfectly aligned edges

Aadh2p: an Arxula adeninivorans alcohol dehydrogenase involved in the first step of the 1-butanol degradation pathway

Additional file 3: Figures S3. Key compounds of the ß-oxidation - microarray studies. The SBGN style metabolic network depicts reversible (double headed arrow) and irreversible (single headed arrow) reactions catalyzed by the corresponding enzymes (rectangular square). Enzymes are enriched with color-coded fold change values of time resolved expression data of the respective genes. The colors represent upregulation (blue) and downregulation (red) of genes in cells shifted to medium containing 1-butanol as the carbon source compared to cells grown with glucose. Metabolites or enzymes occurring multiple times in the metabolic network are decorated with a clone marker (e.g. CoA) (produced using VANTED [2, 3])

Teaching Power-Sector Models Social and Political Awareness

Energy-system scenarios are widely used to relate the developments of the energy supply and the resulting carbon-emission pathways to political measures. To enable scenario analyses that adequately capture the variability of renewable-energy resources, a specialised type of power-sector model (PSM) has been developed since the beginning of this century, which uses input data with hourly resolution at the national or subnational levels. These models focus on techno-economic-system optimisation, which needs to be complemented with expert socioeconomic knowledge in order to prevent solutions that may be socially inacceptable or that oppose political goals. A way to integrate such knowledge into energy-system analysis is to use information from framework scenarios with a suitable geographical and technological focus. We propose a novel methodology to link framework scenarios to a PSM by applying complexity-management methods that enable a flexible choice of base scenarios that are tailored to suit different research questions. We explain the methodology, and we illustrate it in a case study that analyses the influence of the socioeconomic development on the European power-system transition until 2050 by linking the power-sector model, REMix (renewable-energy mix), to regional framework scenarios. The suggested approach proves suitable for this purpose, and it enables a clearer link between the impact of political measures and the power-system development

Agdc1p - a gallic acid decarboxylase involved in the degradation of tannic acid in the yeast Blastobotrys (Arxula) adeninivorans

Tannins and hydroxylated aromatic acids, such as gallic acid (3,4,5-trihydroxybenzoic acid), are plant secondary metabolites which protect plants against herbivores and plant-associated microorganisms. Some microbes, such as the yeast Arxula adeninivorans are resistant to these antimicrobial substances and are able to use tannins and gallic acid as carbon sources. In this study, the Arxula gallic acid decarboxylase (Agdc1p) which degrades gallic acid to pyrogallol was characterized and its function in tannin catabolism analyzed. The enzyme has a higher affinity for gallic acid (Km -0.7 ± 0.2 mM, kcat -42.0 ± 8.2 s-1) than to protocatechuic acid (3,4-dihydroxybenzoic acid) (Km -3.2 ± 0.2 mM, kcat -44.0 ± 3.2 s-1). Other hydroxylated aromatic acids, such as 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, 2,3-dihydroxybenzoic acid, 2,4-dihydroxybenzoic acid and 2,5-dihydroxybenzoic acid are not gallic acid decarboxylase substrates. A. adeninivorans G1212/YRC102-AYNI1-AGDC1, which expresses the AGDC1 gene under the control of the strong nitrate inducible AYNI1 promoter achieved a maximum gallic acid decarboxylase activity of 1064.4 U/l and 97.5 U/g of dry cell weight in yeast grown in minimal medium with nitrate as nitrogen source and glucose as carbon source. In the same medium, gallic acid decarboxylase activity was not detected for the control strain G1212/YRC102 with AGDC1 expression under the control of the endogenous promoter. Gene expression analysis showed that AGDC1 is induced by gallic acid and protocatechuic acid. In contrast to G1212/YRC102-AYNI1-AGDC1 and G1212/YRC102, A. adeninivorans G1234 [δagdc1] is not able to grow on medium with gallic acid as carbon source but can grow in presence of protocatechuic acid. This confirms that Agdc1p plays an essential role in the tannic acid catabolism and could be useful in the production of catechol and cis, cis-muconic acid. However, the protocatechuic acid catabolism via Agdc1p to catechol seems to be not the only degradation pathway