Iranian Journal of Wood and Paper Science Research
Year:2019 | Volume:34 | Issue:2 (67)|Papers Count:13

Non-destructive tests play a vital role in human life. Non-destructive evaluation technology is widely used in industries, especially wood based industries and wood based products which has led to advances in strength grading lumber, determination of d the disadvantages of wooden materials, inspection of timber and wooden structures. The purpose of this research was to estimate the dynamic flexural strength and compare with the results of static standard tests in two pine (Pinus sylvestris) and Beech (Fagus orientalis) wood. The results of the comparison of the the estimated modulus of rupture by a non-destructive free vibration method in a free supported beam with similar results from the static test showed a very good correlation So, according to calculations done by applying a safety coefficient of 18% for beech species and 11% for pine species, a non-destructive vibration test can substituted the static destructive standard test for estimating the factors mentioned in these two species.

In the present study, we have evaluated the behavior of consumers in the decision-making process to purchase domestic and foreign household furniture. In this study, the statistical population was the total number of household wooden furniture customers, among which 385 were selected based on the table of Krugis-Morgan and by random sampling method. After conducting initial research and studies, considering the issues raised and the importance of the subject and determination of the research objectives, the 5 latent variables have been identified as cultural, preferential, sales, quality and beauty factors as the effective indicators for purchase of wooden household furniture and selection of imported products in comparison with domestic products were designed. To collect inferential data, a researcher made questionnaire and for library data, the study of resources, theses and research articles in this regard were used. Data were analyzed, by SPSS software in the descriptive statistics and by Lisrel software to determine the relationship between variables for structural equations. The results showed that the research model has been fitted in the first-grade and in the structural model. In measurement model, the measurement indices have created some meaningful factor loadings. This issue shows that this model has correctly been determined from theoretical literature and the criteria of this measurement have been recognized correctly. This caused a high validity of the measurements ‘ tools. Also, all the mentioned latent variables and its dimensions as the structures of the proposed structural model effect on customer preferences in the decision-making process of foreign and domestic household wooden furniture purchase.

In this paper, barriers to the export of furniture from Iran have been identified and ranked using interpretative structural modeling (ISM). In order to identify the barriers to export, first the research background was investigated and a list of barriers was extracted. Then, with a number of experts in the field of furniture production and sales, in-depth interviews and semi-structured interviews took place. The integration of barriers from theoretical studies and field studies was considered as the final list. In the next step, the relationship between the barriers was investigated pairwise, and the matrix of paired comparisons was completed. Based on interpretive structural modeling and final conceptual model, the level of each of the barriers are recognized. Modeling results indicate that Iran's weak political relations with other countries are the main driver of poor export. Secondly, exchange rate fluctuations, lack of supply of raw materials and poor relations with embassies are also among the root causes.

In this study, the effect of pigment composition on the properties of paper prepared from bleached CMP pulp was studied. The purpose of this research was to achieve the best combination for coating of the paper to improve physical and optical properties while maintaining strength properties. Three different pigment combinations (100% calcium carbonate (GCC), 70% calcium carbonate and 30% kaolin clay (70GCC30Clay) and 70% calcium carbonate and 25% gritty and 5% titanium dioxide (70GCC25Clay5TiO2)) were made with the addition of anionic starch, latex and dispersant and was used for coating. Physical properties included (surface roughness of the paper, ash content and apparent density) and the optical properties included (brightness, absorption and diffusion coefficient) and paper strength characteristics including tensile strength, bursting resistance, tear strength using standard TAPPI test methods. Factorial design, and analysis of variance was performed and the mean properties values were compared using Duncan's test. By adding clay and titanium dioxide to calcium carbonate, the roughness of the paper surface decreased the highest roughness of the surface of the paper was observed for the control paper and the lowest was seen in the treatment of 70GCC30Clay surface. Also, the highest degree of brightness is related to 70GCC25Clay5TiO2 treatment. The highest tensile strength and burst strength indices were related to gypsum treated paper (GCC) and also the highest tear strength index was measured on treated paper at level 2 (70GCC30Clay).

This study investigated the comparative tension and compression strength of detachable edge joints in MDF and particle boards. Five pieces of each samples were made in L shape with the size of 20*20 cm according to D 1761 ASTM. Fittings were applied in three types: cross, hexagonal shape and plastic fitting with 2 types of counter sink and butt screw were used. The results showed that the highest value of tension strength was in cross shape metal joints and highest compression strength in hexagonal joints. Also the lowest strength of both tension and compression was observed in plastic joints. According to the results, the joints with counter sink screws had higher strength than butt screw, and the failure location in this samples was like crevice in the bottom of boards. The data showed that the tension strength of all three fittings were higher than compression strength. The highest values of tension stress was in MDF using glue and dowel, counter sink screw and cross shaped fitting and the lowest was in particle boards without dowel, butt screw and plastic strips. The highest value of compression stress was related to MDF with glue and dowel joint, hexagonal metal strip and counter sink screw, the lowest was seen in particle board without dowel, butt screw, and plastic strip.

The aim of this study was to investigate the effect of storage and bleaching of cotton pulp on stability of optical properties of bond paper. Industrial unbleached cotton pulp with the freeness 13° SR, in two types of static and agitating storage was stored for 3-15 days in room temperature and the pulp was bleached with hydrogen peroxide. Then, standard handsheets were made from bleached pulp and after air-drying, the sheets were aged by UV and thermal methods and their optical properties measured. Results showed that agitated samples had higher brightness and whiteness and lower yellowness than static ones and by increasing of storage time this numbers be much and less, respectively. In case of UV treated samples, the brightness and opacity of static samples decreased and agitated ones increased. The brightness of static and agitated samples with thermal treatment showed up and dawn trend, respectively. Also, UV and thermal treatments, especially in static samples lead to much yellowness and much whiteness in agitated ones. Therefore, agitated storage method was better than the static one to provide suitable optical properties before and after bleaching. In addition, paper made from agitated storage samples had more desirable characteristics and the influence of temperature was more than UV in immediate and longtime.

In this study, biometrics, physical and microscopic properties of Ficus carica wood were investigated. Three healthy Ficus carica trees in Mazandaran province were selected and felled. Three discs of 5 cm thickness were prepared along the tree (breast height, 1. 9 m height and near the crown). In the transverse direction, 2 × 2 × 2 cm test specimens were sequentially taken from the pith to the bark and examined for physical and biometric properties of the fibers. Then the biometric properties of fibers including fiber length, fiber lumen diameter, fiber diameter and cell wall thickness were measured. Physical properties including basic density, oven dry density, longitudinal shrinkage, radial shrinkage and tangential shrinkage were calculated. Microscopic sections of three surfaces (transverse, tangential and radial) of Ficus carica tree was prepared and the anatomical characteristics of the wood was determined and indexed by IAWA. Anatomical studies near the pith and bark of this wood revealed differences. The most important of these differences are the presence ofTyloses in the vessel lumen near the pith and the absence of this in the near bark, homogeneous rays near the bark and heterogeneous rays in the near pith. The mean tangential vessel diameter near the bark (105 μ m) was larger than near pith (70 μ m) and wood rays were wider near the bark than near the pith. Ficus carica tree was determined to be diffuse porous hardwood species, distinct growth ring, axial parenchyma vasicentric and banded, simple perforation plates. Inter-vessel pits alternate and containing prismatic crystals in parenchyma. The results showed that there were significant differences in both the transverse and longitudinal directions of Ficus carica tree in terms of fiber length, fiber lumen diameter, fiber diameter and cell wall thickness. As the biometric properties of the fibers increased from pith to bark, the mean length, fiber diameter, fiber lumen diameter and cell wall thickness were measured as 1. 05 mm, 30. 47 μ m and 23. 6 μ m and 5. 42 μ m, respectively. The results showed that radial shrinkage, tangential shrinkage, basic density, oven dry density of the pith towards the tree bark had an upward trend and downward from the bottom of the tree towards the crown.

In this research, the effect of Polyvinyl acetate (PVAc) adhesive modified by carbon nanofibers (CNF) reinforcement were studied using three levels (0%, 0. 4%, 1. 5%) of carbon nanofibers on the strength properties of joints commonly used in the furniture industry. Modified carbon nanofibers were used as chemically modified surface to improve the dispersion in polymer matrix. The test specimens were made using cut out medium density fiber board (MDF) pieces with required dimensions and dowel wooden with 6, 8 and 10 mm in diameter, and penetration depth at three levels using polyvinyl acetate adhesive reinforced with modified carbon modified nanofiber. Totally, 27 treatments and three replication were used. The evaluation of the bending moment capacity of test specimens made with freshly formulated adhesive and the effect of other variables was performed on the joints made under tensile loading at a speed of 3 mm/min. The results showed that increasing the percentage of carbon nanofibers, the diameter of the wooden dowel and the penetration depth and the moment capacity compared to the control samples was increased by 1. 6, 1. 5 and 1. 3 times, respectively. The 0. 4% w/w carbon nanofibers, 10 mm diameter and L3 wooden dowel penetration depth had the greatest effect on the strength of the joints.

Ethylene vinyl alcohol (EVOH) copolymer is of semi crystalline materials with excellent barrier properties to gases. Also, it has shown outstanding chemical resistance. Despite its low gas permeability, EVOH copolymer displays poor water and water vapor resistance. In this study, Trimethoxymethylsilane (as hydrophobic coating) was deposited by Plasma Enhanced Chemical Vapor (PECVD) method on the coated paper with Ethylene vinyl alcohol in order to improve the paper's barrier properties of moisture transmission. Coating by PECVD method was done in the certain conditions of time 6 min, pressure 300 m Torr, power including 50, 70 and 90W. Then contact angle was measured in order to determined improvement of the paper's barrier properties of moisture transmission. The result showed that papers which were coated with Trimethoxymethylsilane had higher contact angle water 55. 7% more than the control. The results revealed that the best condition was obtained by 50 W power. The structural and chemical properties of deposited layer were observed with Fourier Transform infrared spectroscopy-Attenuated Total Reflectance (FTIR-ATR) and Energy Dispersive X-ray Spectroscopy (EDS). The results confirmed bonding of silane on the surface EVOH polymer.

Bending strength of poplar species (Popolus deltoids) and eucalyptus (Eucalyptus spp) I-joist with reduced weight using two methods of crinkling and honeycombing was studied. Investigated variables was including: a) type of flange, b) configuration of lightened core layer in web and c) thermal-pressure treatment surface layers of web. Flange type at two levels: 1) LVL from poplar wood and 2) eucalyptus wood, configuration of web core layer at two level: 1) crinkle and 2) honeycomb and type of treatment applied on surface layers of web which were prepared from poplar layers with 3 mm thick at two levels: 1) thrmo-compressed treated and 2) untreated veneers. Mechanical properties of beam including modulus of rapture (MOR) and modulus of elasticity (MOE) were selected and tested as dependent variables. Results were statistically analyzed in full factorial plot, . After determination of results significance results, means of values were classified by Duncan Multiple Range Test (DMRT). Results showed that using LVL from poplar unlike its low density had higher MOR and MOE values compared with eucalyptus wood. Inaddition, in order to reduce the weigth of the beam, using honeycomb configuration in web core layer generated higher strength in comparison with crinkle configuration. Treatment of surface layers of web had no effect on bending strength, statistically.

Paper is a dominant tool that is traditionally used for recording human knowledge and cultural heritage. Paper as organic material is at risk of biodegradation processes by various microorganisms including fungi, which cause irreversible degradation, color modification and instability of the historical papers. Thus, the utilization of appropriate conservation methods and restoration treatments to minimize the adverse effects of fungi on historical papers have received great attention. Recently, Benomyl as an antifungal revealed a significant inhibitory effect on the fungal growth on the historical papers. In this study, the effect of Benomyl on gall ink as a popular and important ink used in cultural heritage was investigated. In a first step of the evaluation, the gall ink was prepared based on the historical recipes and then was implemented on surface on filter paper. The prepared samples were dipped into 100 ppm Benomyl-ethanol solution and aged after drying. The effect of Benomyl on gall ink was evaluated by the pH values of aqueous extracts, CIE Colorimetry, paper strengths, FTIR-ATR spectroscopy and SEM microscopy. Results indicated that the Benomyl in concentration of 100 ppm had no adverse effect on the gall ink and paper surface. However, dipping of paper in the Benomyl-ethanol solution resulted in a significant loss of paper strengths. In order to overcome this problem, it would be necessary to use a suitable solvent or another technique such as spraying surface application of Benomyl.

Cellulose is the most abundant bio-polymer and has many potential and applications, Therefore, in order to convert it to solvable cellulose in many commercial solvents, it is necessary to modify the cellulose structure with a variety of methods of derivation. Cellulose derivatives have an increasing share in the cellulosic products marketing and it is used in various industries such as sanitary, pharmaceutical, food and industrial. Carboxymethyl cellulose is one of the most important commercial cellulose ether derivatives. The purpose of this study was to investigate the conversion of alpha-cellulose derived from the poplar species into a useful and more valuable product that called Carboxymethyl cellulose. In order to optimize and investigate the interaction of different process variables, response surface methodology (RSM) was used. For modeling the process, important operational parameters such as concentration of NaOH, ratio of Monochloroacetic acid to cellulose, temperature and the time of etherification as independent variables and the degree of substitution of the samples were considered as the desirable response. Analysis of variance and response level were used to create a function between variables and responses, and optimal conversion conditions were determined. The results showed that the best value presented in the optimal condition proposed by software for the degree of substitution was 31 percent for concentration of etherification, 1. 09 for the ratio of Monochloroacetic acid to cellulose, 60 ° C for the etherification temperature and 157 minutes for the etherification time.

In this study, the composition of bagasse composite was investigated using different amounts of bagasse particles. Bagasse and cement particles are manufactured at levels (5, 10 and 15%) and percentage of calcium chloride as cement accelerating additive at two levels (3 and 2%) based on cement dry weight. Then, the mixture was poured into a mold measuring 15 8 18 8 8 cm and the excess water was removed from the bottom of the mold and initially weighed 10 kg on the specimens. The specimens were removed from the mold after 48 hours and kept in a glass saturated room at 90% humidity for 14 days and then finally dried in a laboratory environment. The bending strength and physical properties tests were performed on the specimens. The results showed that bagasse particles had a significant effect on bending strength and other physical properties. The bending strength was highest in boards made with 10% bagasse particles.