WOOD RESEARCH Volume 68, Number 3, 2023
Dénes Horváth, Sándor Fehér, and Mátyás Báder

The Potential of Producing High Added Value Structural Timber from Lamellae Waste. Classification and Visual Grading

This study is the continuation of the first part (Horváth et al. 2023), in which density, bending strength and modulus of elasticity of 100 oak lamellae generated as small-sized production waste were investigated. In this part of the study series, the classification of our sample set is carried out according to the EN 338. A visual pre-grading is presented, to remove the worst specimens and achieve a better final result and a standardized visual grading is also shown. Our results are compared with literature values of clear specimens as well. Amount of 80% of the specimens were found to be suitable for further structural use. The total sample set is classified in strength class D35 (average density 712.6±72.5 kg/m3; average MoRadj 65.4±16.2 MPa; average MoEadj 13.4±3.1 GPa), while the visually pre-graded part with better average test results is classified in strength class D45. Industrial wood residues contain a sufficiently high proportion of elements for further processing, so that after sorting it can be used as raw material for glued-laminated load-bearing timber.

WOOD RESEARCH Volume 68, Number 1, 2023
Dénes Horváth, Sándor Fehér, and Mátyás Báder

The potential of producing high added value structural timber from lamellae waste. Test results and analysis

The research was based on the analysis of the density, bending strength and modulus of elasticity of 100 oak lamellae generated as small-sized production waste. In this part of the study series, the test results were presented in detail and analysed, in particularly the density distribution. Correlations between some test results have been shown. The dynamic and static test results were also compared. Despite the poor quality lamellae, the average density of the sample set corresponds to literary values and the distribution of density is normal. Specimens with low density are unsuitable for further use. But the density alone cannot be used for classification. Between static and dynamic modulus of elasticity can be found a good relationship. The relationships between density and both static and dynamic modulus of elasticity of the specimens can be considered as good, too. The best correlation is in bending tests between the deflection of the specimens in the elastic range and the bending strength.

WOOD RESEARCH Volume 63, Number 6, 2018
Oswaldo Moreno-Anguiano, José G. Rutiaga-Quiñones, Francisco Márquez-Montesino, José Luis Rico-Cerda, and Artemio Carrillo-Parra

Performance of activated carbon obtained from pine wood and determination of its adsorption capacities of ammonia and gasoline vapors

Two types of pine wood were used to produce activated carbon (AC) by chemical activation with phosphoric acid. The yield of the activated carbon (CAs) obtained by considering the following factors in the process: species, activation temperature and impregnation ratio (R = wood mass/dissolution mass), the variables of such factors being the species Pinus pseudostrobus (Pp) and Pinus leiophylla (Pl), temperature values 400 and 500°C, and values of R (1:1, 1:2, 1:3), respectively, thus having 12 combinations. The results indicate that the best performance was in the treatment with Pp 400°C and with R = 1:1. A surface area of 790 and 801 m2.g-1 and a total pore volume of 0.312 and 0.316 cm3.g-1 were obtained for the Pp 500-2 and Pl 500-2 carbons, respectively. Likewise, the adsorption capacity of ammonia and gasoline vapors of the carbon obtained was determined.

WOOD RESEARCH Volume 63, Number 3, 2018
Mohammad Ahmadi, Siavash Bayani, and Mearaj Sharari

Organosolv pulping of Calotropis procera by mono ethanol amine

In this study, usage of mono ethanol amine (MEA) as an organic reagent was considered in pulping of Milkweed compared with alkaline non-friendly pulping methods including Kraft and Kraft-AQ and soda-AQ. In this case, monoethanolamine was added in various ratios i.e. 100, 75, 50, 37.5 and 25% in replacement with water (MEA-water pulping). Besides, anthraquinone was added in parallel with MEA-water treatments (MEA-water -AQ ) and its effect on pulp properties has been considered. The results indicated that replacement ratio of 75/25, 240 minutes of retention time and with0.1% usage of anthraquinone showed the optimum conditions based as yield and kappa number of the pulp samples. Moreover, at the same degree of delignification, the MEA pulps showed about 15-20% higher yield based on raw material. Total unbleached MEA pulp yield is very high, ranging between 48 to 54% with kappa number of 58. For Kraft, the yield varied between 38 to 43%.

WOOD RESEARCH Volume 65, Number 4, 2020
Ehsan Yousefi, Mohammadreza Dehghani Firoozabadi, Omid Ghaffarzadeh, and Kuňa Vladimír

Investigation of urea usage in soda pulping of Populus deltoides

In this study, the use of the urea was investigated as an additive in soda pulping of Populus deltoides in comparison with the conventional soda and Kraft processes. Urea was used at the ratios of 1.5%, 3%, 4.5%, and, 6% based on the dry weight of wood in the soda process. The constant factors were determined for each distinct cooking of soda, soda-urea, and Kraft treatments. The dry weight of the chips was 150 g, the ratio of the liquor to wood (L/W) 4: 1, the maximum temperature 170°C and active alkaline content 18% (based on Na2O). Cooking time, the only changing factor, was varied from 30 to 330 min depending on the type of cooking. Besides, the sulfidity ratio was 25% for all Kraft treatments. After ending pulping time, the pulp samples were fully washed. Then, the screen accepts and the screen rejects were evaluated using a 20 and a 200-mesh screen. The observation shows that the more urea usage is in a pulping liquor, the more total yield, however, the screen reject value unexpectedly increased. Hence, the optimum values were determined by 1.5% and 3%. The investigation of handsheet samples indicated an increment trend of mechanical strengths with an addition of urea; so that the tear, tensile, and burst indexes of soda-urea samples were significantly higher than for each symmetric soda sample. It has been supposed that cellulose carbamate is essential in the enhancement.

WOOD RESEARCH Volume 64, Number 1, 2019
Faustino Ruiz-Aquino, Sandra Ruiz-Ángel, Javier R. Sotomayor-Castellanos, and Artemio Carrillo-Parra

Energy characteristics of wood and charcoal of selected tree species in Mexico

This study determines the main energy characteristics of wood and charcoal within five tree species of the forest of Ixtlán de Juárez, Oaxaca, México: Alnus acuminata, Arbutus xalapensis, Myrsine juergensenii, Persea longipes and Prunus serotina. Basic density, moisture content, charcoal yield, volatile material, ash content, high heating value, fixed carbon and fuel value index were determined for each one. The average results of the species are in the range of 0.372 to 0.498 g. cm-3 for wood density; 26.19 to 34.12% for charcoal yield; 77.29 to 83.66% for wood volatile matter and 28.40 to 34.25% for charcoal volatile matter; 0.56 to 1.50% for wood ash and 1.13 to 4.83% for charcoal; 19.50 to 24.99 MJ. kg-1 for high heating value of wood and 29.38 to 32.11 MJ. kg-1 for charcoal. It was determined that these species provide a good alternative for burning wood and charcoal. Additionally, these remain untapped resources in the Sierra Juárez region, meaning that awareness and inclusion in management plans could be of relative importance to the development of the forestry sector.