Volume 6 Issue 4

This study described a process of making ultra-low density fiberboard (ULDF) and investigated the properties of samples of ultra-low density fibreboard made from wood fiber using a liquid frothing approach. The fiberboard had a density of 56.3 kg/m3 and a layered cross-linked interior structure. Density profiles showed a relatively high density in the surface layers and low density in the core layer. The results showed that the fiberboard had an internal bond strength of 0.15 MPa, a modulus of rupture of 0.70 MPa, a modulus of elasticity of 8.91 MPa, and a compressive strength of 0.17 MPa at 10% deformation. Thickness swelling after 24 hours water immersion was 0.57%. It had a low thermal conductivity of 0.035 W/mK, and a high sound reduction coefficient of 0.67. Resin was uniformly distributed on the fiber surface. The fiberboard can be used as buffer material for packaging and insulation material for building.

Effects were studied of 200 ppm nano-silver suspension on physical and mechanical properties of particleboard made on an industrial scale at the Iran-Choob Factory. Nano-silver suspension was added to the mat at two levels of 100 and 150 milli-liters/kg dry weight wood particles and compared with control boards; all the other manufacturing variables remained constant. Results showed that hot-pressing time was reduced by 10.9% and 10.1% when 100 and 150 mL of nano-silver were used, respectively. Also, both levels of nano-silver consumption had improving effects on physical and mechanical properties, although in some cases not statistically significant. It can be concluded that heat-transfer property of nano-silver particles in the mat can be used to reduce the hot-press time as the bottle-neck of nearly all wood-composite factories, as well as to reduce the heat gradient and consequently to improve physical and mechanical properties of composite-boards.

The unknown nature of the future requires us to question our decisions and seek reliable methods. The artificial neural networks approach, which is one of the methods used to best predict the future and one that is important for decision making has been thought of, particularly in recent years, as a method with a high level of validity in the fields of economy and financial prediction. The Istanbul Stock Exchange (ISE), at which millions of national and international investors operate, is among the developed stock exchanges of the world. The ISE has the attributes of being appropriate for making predictions regarding financial returns, without any sector differentiation, as a whole. In this study, it was aimed to predict monthly stock yields of 14 different paper companies dealing with the ISE (Istanbul Stock Exchange) by using artificial neural network. Four different variables (the gold price, ISE daily trading volume, exchange rate purchase-sale average, and monthly deposit interest rates by utilizing) and 127 months data were used. Results show that the monthly stock yields of the paper sector can be predicted correctly to account for 95% of the variability of data with the artificial neural network model, and the average absolute percentage failure value was 6.85%.

Ni/CeO2-ZrO2 catalysts were prepared via co-precipitation and characterized by N2 adsorption–desorption, XRD, SEM, and TPR techniques. The effects of reaction temperature, carbon-equivalent space velocity (GC1HSV), and steam-to-carbon ratio (S/C) on the performance of the catalysts for ethanol steam reforming (ESR) were investigated. It was found that the best catalytic performance was obtained over the Ni/Ce0.75Zr0.25 catalyst with GC1HSV=345 h-1 and S/C=9.2. Under these conditions, H2 selectivity reached its highest value of 98% at T=725 °C, and carbon conversion reached 100% at T=825 °C. The performances of Ni/Ce0.75Zr0.25 and Ni/Ce0.5Zr0.5 were also compared at S/C ranging from 2.5 to 9.2. The results showed a higher carbon conversion for the Ni/Ce0.75Zr0.25 catalyst than for Ni/Ce0.5Zr0.5.

Two different agricultural wastes, sunflower stalk and tobacco stalk, were evaluated for the production of xylose, which can be used as a raw material and converted to xylitol, a highly valued product. The objective of the study was to determine the effects of H2SO4 concentration, temperature, and reaction time on the production of sugars (xylose, glucose, and arabinose), and on the reaction by-products (furfural and acetic acid) from sunflower stalk and tobacco stalk and to compare the hydrolysis conditions of these wastes. Since both agricultural wastes had different structures, they had different responses to experimental conditions. Response surface methodology (RSM) was used to optimize the hydrolysis process in order to obtain high xylose yield and selectivity. The optimum reaction temperature, reaction time and acid concentration were 120 oC, 30 min and 4% of acid concentration for sunflower stalk and 133 oC, 27 min and 4.9% of acid concentration for tobacco stalk.

Biosorption was carried out in a batch process to test the suitability of corncob for the removal of manganese ion (Mn(II)) from aqueous solution. The amount of metal ions removed from solution depended on the metal ion-substrate contact time, ion concentration, temperature, and pH. The adsorption capacity of the biosorbent from corncob was also enhanced by treatment with acid. Kinetic modeling of the data obtained from the study showed that the biosorption of Mn(II) ions by the untreated and acid-treated corncob followed the Largergren pseudo-first order model. The adsorption capacity of the raw biomass was found to be 6.54 mg/g, while acid-treated biomass showed an adsorption capacity of 7.87 mg/g. The data obtained from this study fitted well with the Freundlich and Langmuir adsorption isotherms.

The Raffia textilis fiber has interesting specific mechanical properties among other vegetables fibers. But its production remains entirely based on empirical knowledge. The fibers are dried in the open air and in the shade for about 48 hours. This study explores the effect of the drying temperature, from 30° to 70°C, on its drying kinetics. It was found that the drying duration passes from 55 min at 30 °C to 20 min at 70 °C. Among the three models used to simulate the drying kinetics, the Page model yields the best results. The values of the parameters of this model agree with the hypothesis that the water diffusion is one-dimensional. The activation energy of water in the fiber varies from 49 to 71 KJ/mol, depending on the model used. The effective diffusion coefficient is about 3x10-14 m2.s-1 at 30 °C. This low value justifies the traditional use of the raffia leaves for house roofs.

the effect of organic bound Na groups on pyrolysis and gasification behaviors of alkali lignin, an experimental study was carried out by Thermogravimetric Analyzer coupled with Fourier Transform Infrared Spectrometry (TG-FTIR). Acid precipitated lignin (APL) and Alkali soluble lignin (ASL) were selected as the testing samples, and physiochemical properties were studied by FTIR, 1H NMR, and SEM analyses. The research results showed that the pyrolysis and gasification characteristics of alkali lignin depended on phenolic sodium (-CONa) and carboxylate sodium (-COONa) groups (PCSG). In pyrolysis stage, PCSG improved the yields of alcohols and hydrocarbons but inhibited benzenes. During gasification stage, in the present of PCSG, the peak value of gasification rate increased, yet the initial gasification temperature decreased. Meanwhile, CO releasing was relatively concentrated and intensively increased from 37 min (740 oC) to 42 min (840 oC).

With the rapid development of the packaging industry, the requirements for physical properties of corrugated paperboard tend to become higher and higher, especially for the strength properties. A water glass-starch compound system was employed as a surface sizing agent to improve the strength of linerboard in this work. The viscosity of water glass-starch compound system, and its impacts on ring-crush strength and bursting strength of linerboard were evaluated. Cobb value and contact angle were used to characterize the waterproof performance of paper after surface sizing. Compared with conventional surface sizing agents, water glass-starch compound system overcame the defects of low coating weight and inadequate stiffness of the sizing layer, allowing ring-crush strength and bursting strength of linerboard to increase by 91% and 50%, respectively. Additionally, the compound system had higher solids content, low viscosity, and good film-forming ability, which will bring a lot of convenience to production.

The drying process of Norway spruce (Picea abies [L.] Karst) wood exposed to infrared heat radiation was studied by measuring the moisture profiles of the wood samples at controlled temperature during drying. The thermal treatment was executed in a purpose-made industrial pilot-plant containing the heat radiators covered by infrared (IR) transmition filters. The moisture content of the samples was detected at certain stages of the process. Based on the results of exposing the samples to IR radiation for 15, 25, 35, and 45 hours, the drying mechanism of wood is discussed. The moisture transport mechanism was explained by a semipermeable membrane process considering the moisture content as a dilute aqueous solution. If the semipermeable cell wall allows only the passage of water but not that of solute molecules, water diffusing from the region of higher (center) to lower (periphery) water content produces osmotic pressure difference between the two sides of the cell walls. The importance of this osmosis was considered in the approach of moisture migration.