Physics and Mechanical Wood
Ebrahim Khosravi; Amir Lashgari; Mehran Roohnia; Ahmad Jahan latibari; Ajang Tajdini
Abstract
Background and objectives: From the limitations of detecting the amount of useful life remaining in the components of the structures in the conditions of use with acoustic methods is the impossibility of calculating the modulus of elasticity due to the impossibility of removing the part from the structure. ...
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Background and objectives: From the limitations of detecting the amount of useful life remaining in the components of the structures in the conditions of use with acoustic methods is the impossibility of calculating the modulus of elasticity due to the impossibility of removing the part from the structure. Therefore, most of the classifications during use in the components of structures such as historical buildings are based on measuring the speed of sound. In this research, to calculate the local and global density with the method of pin penetration rate in wooden tie in order to calculate the amount of their remaining useful life by combining stress wave and free longitudinal vibration methods has been studied. There was no significant difference between the values of global sound velocity and global modulus of elasticity with the local results of these factors at the five tested points in each of the wooden tie.Methodology: The number of three saturated wooden tie from Iran Railway Company and with the dimensions of 15x25x260 cm, which are made of beech species (Fagus orientalis) and the density was measured by pin penetration method at 5 points of each wooden tie (50 cm distance between each point) and the average results of 5 points were compared with the results of ISO 13910 standard method. The stress wave test was carried out at the same 5 points of density determination by pin penetration rate method to determine the local modulus of elasticity and the results of each point were compared with the global modulus of elasticity of the beam. Longitudinal vibration test was also performed to calculate the damping factor values of the samples.Results: The results showed that there was no significant difference at the 95% level between the values calculated with both the ISO 13910 standard methods and the pin penetration rate method, and there was a favorable linear correlation between the results of the two methods. According to the results, there was no significant difference between the global sound speed of the beams and their local sound speed in any of the five measured points at the 95% level and there was a linear correlation between the values of the global sound speed and each of the five local points. There was no significant difference at the 95% level between the values of the global modulus of elasticity and the values of the local modulus of elasticity calculated in each of the five points. Also, there was a linear correlation between the values of the global modulus of elasticity and the results of the local modulus of elasticity in each of the five points. There was an exponential correlation between the values obtained from the global modulus of elasticity and the damping factor of each of the wooden tie.Conclusion: The equality of density according to the ISO 13910 standard method and the nail penetration method, as well as the equality of the modulus of elasticity calculated by the stress wave method and the free longitudinal vibration method, make it possible to obtain all the data required for calculations without removing the part from the structure. The remaining strength of wooden components should be provided according to EN338 standard.
Chemical conversion
Zahra Daeepour; amir lashgari; Mehran Roohnia; Ahmad Jahan latibari; Vahid Safdari
Abstract
Background and objectives: Nowadays, the importance of treatments such as water washing and ethanol-acetone washing to improve the acoustic properties of wood has been noticed by the makers of musical instruments. Wood extractives are in the list of those materials that often do not have a construction ...
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Background and objectives: Nowadays, the importance of treatments such as water washing and ethanol-acetone washing to improve the acoustic properties of wood has been noticed by the makers of musical instruments. Wood extractives are in the list of those materials that often do not have a construction role, and their purposeful and correct evacuation can lighten the wood without reducing the stiffness. Carrying out pre-treatments such as fermentation with bread yeast (before water washing and ethanol-acetone washing processes) can lead to the extraction of more extractable substances from wood. In this study, the effect of water washing and ethanol-acetone washing treatments as well as fermentation pre-treatment on the acoustic properties of Ash wood (Fraxinus excelsior) has been investigated.Methodology: Ash wood species (Fraxinus excelsior) was prepared from the wood of a commercial timber and 38 small radial beams with nominal dimensions of 150×12×2 mm (longitudinal×radial×tangential) were extracted from the hardwood. After reaching the equilibrium humidity of 12% in air-conditioned conditions, the selected samples were subjected to the forced vibration test in the free-free beam in order to measure the basic physical and acoustic characteristics. After that, the initial tests were randomly divided into two groups of 19 tests. The first group without pretreatment and the second group with fermentation pretreatment were placed in the process of removing the extractives by water and then by ethanol-acetone mixture. After each step of water washing and removing the extractive substances soluble in ethanol-acetone mixture, the forced vibration test in the free-free beam was performed on the samples and the acoustic properties of the samples were measured.Results: Water washing without pretreatment with bread yeast caused a slight decrease and with pretreatment, it caused a significant decrease in density values (respectively: 1.75 and 7.39%). While the process of removing extractives (with and without pretreatment) by ethanol-acetone mixture caused a significant decrease in density values (Respectively: 2.27 and 8.71%). The modulus of elasticity values showed a significant decrease due to water washing without pretreatment and with pretreatment. (Respectively: 11.37 and 16.47%). The process of removing the extractives by ethanol-acetone mixture also resulted in a significant decrease in the modulus of elasticity values in untreated and pretreated samples (Respectively: 13.87 and 20.93%). Water washing without pre-treatment with bread yeast and with pre-treatment has caused a significant decrease in the values of damping factor, among which the pre-treated samples had a greater percentage of drop in the values of damping factor (Respectively: 13/87 and 20.93%). The process of removing the extractive materials by ethanol-acetone mixture as washing has caused a significant decrease in the damping factor values, which among the pre-treated samples showed a greater percentage drop in the values resulting from this property (Respectively: 3.03 and 18.01%). In this factor, the process of removing the extractive substances soluble in ethanol-acetone mixture (with and without pretreatment) has resulted in a greater drop in damping values (respectively: 6.67% and 20.85%). Acoustic conversion efficiency due to water washing process without pretreatment with baker's yeast caused a slight increase, while pretreatment caused a significant increase in acoustic conversion efficiency values (Respectively: 0.44 and 25.24%). The process of removing extractive materials by ethanol-acetone mixture also caused a significant increase in the acoustic conversion efficiency values, which among the pre-treated samples showed a higher growth percentage in the values of this characteristic (Respectively: 3.41 and 28.90%). Both water washing methods and ethanol-acetone mixture washing were effective in improving the physical (density) and acoustic properties (modulus-elasticity, damping and acoustic conversion efficiency). Meanwhile, the effect of ethanol-acetone mixture washing was more than the effect of water washing. Fermentation pretreatment with bread yeast improved the performance of water washing and ethanol-acetone mixture washing treatments.
Chemistry of wood
Mohammad Reza Sabzehparvar; Ahmad Jahan latibari; Shademan Pourmousa
Abstract
Background and Objectives: Plant extractives show unique properties. They impart colors and change the color of wood and generates attractive appearance. Since early days, societies have been utilizing plant extractives in industrial, medical and even as fungicides and biocides. In early times ...
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Background and Objectives: Plant extractives show unique properties. They impart colors and change the color of wood and generates attractive appearance. Since early days, societies have been utilizing plant extractives in industrial, medical and even as fungicides and biocides. In early times this application was based on the professional experiences, but as the sciences were advanced, then the technical and experimental identification and utilization was employed. In general, people look at walnut tree wood and fruit as its economic values. However, scientific research has proved the values of walnut tree extractives. In this study the chemical composition of walnut tree extractives and its variation in two periods of spring and summer as well as the impact of the drying on quantity and quality of the extractive components are investigated.Methodology: Walnut tree leaves from a selected location of an old walnut tree (100 years old) in mountain region of Karaj were collected in spring and summer. One part of the samples was air dried and another portion was used at green moisture condition. Totally four samples were obtained. Ethanol-acetone extraction was according to Tappi T204-05 procedure. The extractive was identified using GC-MASS spectroscopy and the chemical components in the extractives were identified and tabulated. Results: The results revealed that the dried leaves contain fewer chemical compounds compared to green samples which can be an indication that some of the compounds in green sample are volatile and vaporize upon drying. Furthermore, the extractives chemical composition and content varies between spring and summer samples. The major chemical compounds identified were 2-methylneptaline, tri-decan, tetradecan, 2,3-dimethyl naptaline and methylcyclobenzen.Conclusion: The results indicated the seasonal variation of walnut tree extractives. These is also considerable variation in wet and dry samples which can be attributed to the presence of volatile compounds. The odor of walnut leaves is the consequence of existence of such volatile extractives. The absence of some of the compounds in summer samples indicate the seasonal changes of the extractives.
Chemical conversion
mohammad najafianashrafi; Payam Moradpour; Ahmad Jahan latibari; Hamidreza Edalat
Abstract
Poly vinyl acetate (PVAC) adhesive is one of the most important adhesives in wood and furniture industry, which has many advantages such as low cost, environment friendliness and non-toxicity. However, it has some disadvantages such as low water resistance and poor boning strength. In this study, the ...
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Poly vinyl acetate (PVAC) adhesive is one of the most important adhesives in wood and furniture industry, which has many advantages such as low cost, environment friendliness and non-toxicity. However, it has some disadvantages such as low water resistance and poor boning strength. In this study, the effect of nano silica (NS) on the properties of poly vinyl acetate adhesive was investigated. The adhesive formulation with different NS contents (2, 3 and 4%) was added to the PVAC. The structure of the prepared adhesive samples was studied by FT-IR and XRD. We used the wood of Acer tree (Acer cappadocicum) to make joints in this study. Two standards of D882 and ASTM D905 were used for tensile and shear tests, respectively. Results showed that adding NS to PVAC enhanced the tensile strength of films. For example, the tensile strength of prepared films was increased by 30% after adding 4% of NS. Moreover, shear strength test showed that NS up to 3% can improve PVAC bond strength. Viscosity results showed that increasing the weight of NS up to 3% to PVAC glue lead to an increase following a decrease in the viscosity
Management and Economics wood
Sina Mohamadi Nematabad; Shademan Pourmousa; Ajang Tajdini; Ahmad Jahan latibari; Amir Lashgari
Abstract
The applied purpose of this study is to determine and prioritize the components of production sustainability in the courrugated box making industry by using qualitative analysis.Through library studies and review of available resources, seven main components affecting the sustainability of production ...
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The applied purpose of this study is to determine and prioritize the components of production sustainability in the courrugated box making industry by using qualitative analysis.Through library studies and review of available resources, seven main components affecting the sustainability of production in the courrugated box making industry were named: rules and regulations, economic, environmental, technological, social, human resourcess, materials and products and 43 sub-components were identified.By preparing researcher-made questionnaires and distributing it among managers and experts in the courrugated box making industry with the aim of influencing each component and sub-component on production sustainability and their current status, the results were analyzed by relevant tests. All components affecting production stability based on standard coefficients and significance of structural equations as well as predictive criteria for confirmation and quality of data presented with redundancy index with cross-validity showed that the data have the necessary validity to predict. The components were prioritized based on average rank and distance to stability. Based on the results, economic, material, product and technological components showed the shortest distance and bio-environmental components, rules and regulations showed the longest distance to achieve stability in the carton industry. Therefore, in order to achieve sustainable production in the carton industry, environmental components, laws and regulations must be given more attention. Research components were prioritized based on average rank and distance to stability. Based on the results, economic, material and product and technological components showed the shortest distance but environmental, rules and regulations components, showed the longest distance to achieve stability in the industry. Therefore, in order to achieve sustainable production in the industry, environmental, laws and regulations components must be given more attention.
Elham Gudarzi; Ajang Tajdini; Shademan Pourmousa; Ahmad Jahan latibari; Mehran Roohnia
Abstract
This study aims to identify the expectations and preferences of consumers of home and office furniture using nonparametric tests. The statistical population consists of customers of the home and office wood furniture industry in Tehran and a stratified sampling method was used in this study. Cochran ...
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This study aims to identify the expectations and preferences of consumers of home and office furniture using nonparametric tests. The statistical population consists of customers of the home and office wood furniture industry in Tehran and a stratified sampling method was used in this study. Cochran formula was used to determine the sample size. To determine the effective indicators, the researcher studied the available resources and the Van et al.’s model as the basic model and conducted a factor analysis to design the conceptual model of the research. Using a field research, the student t-test and Friedman test, she examined the relationship between consumer preferences and 5 factors and 17 subindices. Results: The reliability of the questionnaire was confirmed by the data obtained from 100 questionnaires using Cronbach's alpha. The results of descriptive statistics indicated that the mean of all the indices was at an average level. The minimum and maximum values and the standard deviation showed that there were no outliers. The results of inferential statistics in SPSS software indicated that as the significance level for Kolmogorov-Smirnov test was greater than 5%, all variables are assumed to be normally distributed. The results indicated a significant relationship between all indicators and consumer preferences regarding home and office furniture. The results of the one-sample t-test indicated that consumers consider corporate responsibility factors, product and vendor’s characteristics and internal factors above average while they consider environmental and safety factors at the average level in the purchase of home and office furniture. The results of the Friedman test indicated the priorities as follows: vendor’s characteristics, internal factors, corporate responsibility factors, product characteristics and safety and environmental characteristics.
Bahram Mardani; Ahmad Jahan latibari; Ajang Tajdini
Abstract
Natural disasters and the need to facilitate and relief the consequences of such disasters has initiated global crisis in its respective management. Reducing the variabilities of inhabitants requires the integrated system to battle against such devastations and crises. This research presents the application ...
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Natural disasters and the need to facilitate and relief the consequences of such disasters has initiated global crisis in its respective management. Reducing the variabilities of inhabitants requires the integrated system to battle against such devastations and crises. This research presents the application of Delfi method to identify the influential factors on risk management model risk management model for the wooden structures in Iran. The statistical population of the study consisted of the academic and organizational experts. A total of 30 individuals were interviewed using a purposive non-random sampling technique as well as data adequacy and saturation principle. A semi-structured interview was used to collect the required data. Delfi method was applied for data analysis in qualitative section. The results indicated that 43 risk factors are influential in wooden structures which can be classified as internal and external risks. Among these risk factors, 11 are considered as the major factors which influences the application of risk management in construction of wood structures in earthquake prone regions of Iran.
Physics and anatomy
Farshid Basiji; Vahid reza Safdari; Ahmad Jahan latibari; Amir Nourbakhsh
Abstract
The objective of adding reinforcing fillers, such as natural fibers to plastics is to increase the strength compared with neat plastic and wood. In this research the effect of wood pulp fiber length (short, medium and long), aspect ratio and fiber content (27%, 37%, 47% and 0% (non-reinforced PP)) with ...
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The objective of adding reinforcing fillers, such as natural fibers to plastics is to increase the strength compared with neat plastic and wood. In this research the effect of wood pulp fiber length (short, medium and long), aspect ratio and fiber content (27%, 37%, 47% and 0% (non-reinforced PP)) with 3% maleic anhydride grafted polypropylene on wood plastic composites (WPCs) has been studied. Results showed that increased fiber length or aspect ratio and fiber content increases mechanical properties (tensile strength, tensile modulus and MOE). Impact strength had an inverse correlation with fiber content and fiber length, but fiber content was a much more important factor than fiber length for impact strength. The impact strength of composite of softwood pulps was much higher than wood floor composite plastic. The significant interaction between fiber length and fiber content, and the lack of a specific trend in the treatments made assessment of the effect of fiber properties on MOR difficult.
Pulp and paper
Abdolrahim Mohebalian; Ahmad Jahan latibari; Ajang Tajdini; Shadman Pourmosa
Abstract
In this research, the influence of two temperatures (60 and 90°C) and three dosages of sodium hydroxide (5, 7.5 and 10%, based on the dry weight) on hornbeam wood chips alkaline pre-hydrolysis and soda pulping was studied. Soda pulping of both pre-hydrolyzed and control chips were conducted applying ...
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In this research, the influence of two temperatures (60 and 90°C) and three dosages of sodium hydroxide (5, 7.5 and 10%, based on the dry weight) on hornbeam wood chips alkaline pre-hydrolysis and soda pulping was studied. Soda pulping of both pre-hydrolyzed and control chips were conducted applying constant pulping variables. The effect of pre-hydrolysis on hemicelluloses removal and sodium hydroxide consumption and pulp characteristic including total yield, reject, pulp freeness, kappa number, and pulp strengths were measured and statically analyzed. In case the effect of variable on measured property was statistically significant, then Duncan multiple range grouping of the measured property was arranged. The result revealed that pre-hydrolysis removed almost 4.2% (based on dry wood) of hemicelluloses of the wood and pre-hydrolysis demonstrated easier soda pulping delignification, due to weakening the lignin-carbohydrate bonds and both total yield, reject and kappa number were reduced. Tensile strength index of the pulp produced using pre-hydrolyzed chips war lower and as the dosage of sodium hydroxide increases, the tensile strength index was reduced initiated from the removal of hemicelluloses which is also lower than control pulp, Tear strength index of the soda pulp from pre-hydrolyzed chips was mildly reduced which is anticipated to be the consequence of fiber weakening and fiber breaking during cooked chips defibration. The effect of pre-hydrolysis variables on tear strength was not statistically significant. Based on the result of this study, hornbeam wood can be a potential source of bio-refining based on lignocellulosic material.
Management and Economics wood
Meraj Sharari; Ahmad Jahan latibari; Gholamreza Rafiei; Ahmad Mirshokraei
Abstract
In the course of enhanced bioremediation, addition of nutrients such as carbon, nitrogen, phosphorous, etc, substrates, electron acceptors as well as vitamins (Thiamin, etc) and veratryl alcohol, increased metabolic activities, will influence the production of enzymes and enhances the deterioration of ...
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In the course of enhanced bioremediation, addition of nutrients such as carbon, nitrogen, phosphorous, etc, substrates, electron acceptors as well as vitamins (Thiamin, etc) and veratryl alcohol, increased metabolic activities, will influence the production of enzymes and enhances the deterioration of pollutants. In this study, the effect of 1% (V/V) of nutrients containing various mineral salts, carbon (glucose and malt), nitrogen (casein peptone yeast extract) and some enzyme inducer, such as veratryl alcohol and thiamin hydrochloride on production of laccase, peroxidase and xylanase enzymes by Phanerochaete chrysosporium in bagasse preparation effluent is investigated. The results showed that MSB+MCTV is the most effective additive which causes the highest lignolitic activity of this fungus after 5 to 7 days in case of laccase and peroxidase and 3 days for xylanase, and maximizes the production of the enzymes. The production of these enzymes is measured at 78, 193 and 60 U/l respectively. However, in conditions without additives, the relevant values are 26, 54 and 16 U/l respectively. The relation between different stages of fungus growth and enzyme production and changes in lignin and carbohydrate of effluent after the period of nine days is also investigated.
Physics and Mechanical Wood
Mehran Roohnia; Ahmad Jahanlatibari; Behzad Behnam; Jamshid Zarrinmehr; Mostafa Kohantorabi; Negin Manouchehri; Ajang Tajdini
Abstract
Reaching to the technology of acoustical Tomography and imaging, this project was ordered for facilitating the work for green space researchers and managers in urban standing trees. Comparing the sensors and micro-second timers with those of a certified European device in radial to tangential and longitudinal ...
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Reaching to the technology of acoustical Tomography and imaging, this project was ordered for facilitating the work for green space researchers and managers in urban standing trees. Comparing the sensors and micro-second timers with those of a certified European device in radial to tangential and longitudinal directions showed a good agreement for the Iranian made device. So, a new horizon was opened for the researchers of this approach supported by the local scientific knowledge and technology. Holding this technology, the selected trees concerning the collar defect symptoms were firstly inspected visually, then the visual accuracy was monitored by sonic tomography. Some trees were extremely defected internally, while the visual inspection showed their intactness (9 from 23). Meanwhile some trees holding visually defect signs were proved to be intact after carrying the tomography images (up to 10 from 53). It is concluded that the visual tree defect inspection is not satisfactory for saving or omitting the individual and these kinds of decision makings must be supported by the methods showing the hidden discontinuities.
Composite wood products
Sina Khodaparast; Ahmad Jahan - Latibari; Mehran Rohnia
Abstract
The effect of compounding process applying two methods of one and two step mixing on the properties of nanocomposite is investigated. Nanocomposites were produced using polypropylene, cellulosic fibers, MAPP and nanolay as reinforcement. 1.5 and 3% MAPP and 0,2, and 4% nanoclay were used as the variable ...
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The effect of compounding process applying two methods of one and two step mixing on the properties of nanocomposite is investigated. Nanocomposites were produced using polypropylene, cellulosic fibers, MAPP and nanolay as reinforcement. 1.5 and 3% MAPP and 0,2, and 4% nanoclay were used as the variable factor and 20% fibers was used. Melt flow index was measured on compounds produced using one or two steps mixing. Either compounds were mixed with fibers and MAPP and then the test specimens were made and tested according to ASTM test procedures. The results revealed that the two steps mixing increased the mechanical properties. The melt flow index of one step mixing was lower and the melt flow index of initial mixing of polypropylene with nanoclay was very high and it was reduced after compounding with fibers and MAPP. The results revealed that at higher dosages of the nanoclay tensile and bending modulus of the composite increased and tensile strength and modulus of rupture decreased.
Composite wood products
Ahmad Jahan- Latibari; Roozbeh Abidnejad; Mehran Roohnia
Abstract
At this research, the influence of Multi Walled Carbon Nano Tubes (Non-functionalized and functionalized) on mechanical properties of polypropylene – old corrugated container (OCC) fibers composites was investigated. OCC fibers polypropylene composites were prepared using 20% OCC fibers, 80% polypropylene ...
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At this research, the influence of Multi Walled Carbon Nano Tubes (Non-functionalized and functionalized) on mechanical properties of polypropylene – old corrugated container (OCC) fibers composites was investigated. OCC fibers polypropylene composites were prepared using 20% OCC fibers, 80% polypropylene and 3% MAPP. Three levels of multi walled carbon nano tubes (0% - 0.5% - 1%) were added. Acidic oxidation method was used to functionalize the MWCNTs. Mechanical properties were measured as defined in ASTM testing methods. The results indicated that at higher dosage of MWCNTs, the tensile strength properties of the composite were improved but the influence of the functionalizing was not statisitaclly significant. The bending strength and elasticity as wellas the izod impact were increased as the higher amount of nanotubes were added to the composite. Scanning Electron Microscopes showed the development of bonding between the composite components. Compostes without coupling agent showed lower bonding strength between polypropylene and fiber as indicated by fiber pull out. However, in the composites containing coupling agent, the fiber fracture was observed.
shahram Badamchi; Ahmad Jahan latibari; Mehran Rohnia; Seid Javad Sepideh dam
Abstract
In this research the effect of softwood cellulose fibers surface characteristics on mechanical properties of cellulose fibers / polypropylene composite (W.P.C) was studied. The fibers were refined to modify the surface characteristics and reach four different freeness levels (11, 14, 17 and 21 °SR). ...
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In this research the effect of softwood cellulose fibers surface characteristics on mechanical properties of cellulose fibers / polypropylene composite (W.P.C) was studied. The fibers were refined to modify the surface characteristics and reach four different freeness levels (11, 14, 17 and 21 °SR). Then the fibers were mixed with polypropylene using pre-determined levels of 20% fibers and 77% polypropylene and 3% MAPP and samples were made. The results revealed that refining the fibers will change the strength of the composites. Statistical analysis should that the impact of the different freeness levels statistically influenced the strength at 99% confidence level. The highest strength levels were reached using fibers with the freeness level of 14 oSR.
Pulp and paper
Hosein Valayi; Ahmad Jahan Latibari
Abstract
Strength properties and the yield of soda and soda-ethanol pulps produced using hornbeam, beech and poplar woods were investigated. Soda pulps were produced applying 20% active alkali and the soda-ethanol pulps were made using 10% active alkali and 50% ethanol. The pulping temperature was constant at ...
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Strength properties and the yield of soda and soda-ethanol pulps produced using hornbeam, beech and poplar woods were investigated. Soda pulps were produced applying 20% active alkali and the soda-ethanol pulps were made using 10% active alkali and 50% ethanol. The pulping temperature was constant at 175 C and the soda pulping time was selected at 120 minutes and the soda-ethanol pulping times were 120 and 180 minutes. The highest accepted pulping yield at 58.54% was reached using soda pulping on poplar wood and the lowest yield (49.29%) was related to soda-ethanol pulp produced from beech wood applying 180 minutes pulping time. The accepted yield of soda-ethanol pulping was low, but the kappa numbers of these pulps were almost 20 units lower than soda pulps. The strength properties of soda-ethanol pulps were superior to soda pulps and the difference was statistically significant at 99% confidence level. The results of this study indicated that the delignification of soda-ethanol pulping process is faster than soda pulping from the selected hardwoods especially poplar wood.
Management and Economics wood
Saeed Hasani; Seid Khalil Hosseini Hashemi; Ramin Farsi; Ahmad Jahan Latibari
Abstract
AbstractAmong the forest diseases, fungi are the most important factors that cause irreparable losses to the wood in standing trees and logs. Fungi are the cause of contamination and decay of trees and timbers in forest or in the stock of factories. Decayed woods are one of the biomass resources and ...
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AbstractAmong the forest diseases, fungi are the most important factors that cause irreparable losses to the wood in standing trees and logs. Fungi are the cause of contamination and decay of trees and timbers in forest or in the stock of factories. Decayed woods are one of the biomass resources and a great amount of decayed woods in the forests are not viable. In this study some experiments were conducted in order to investigate the effect of Coriolus versicolor decay on compounds obtained from beech wood (Fagus orientalis L.) pyrolysis and preparation of various and valuable chemicals. Separation and identification of chemical compounds in sound wood and decayed wood of beech was conducted by using pyrolysis method at 500° C and in nitrogen atmosphere. Separation and identification of extracted chemical compounds was carried out using sailylation of these compounds by N, O-bis (trimethylsilyl) trifluoroacetamide and also using Gas Chromatography and Mass Spectrometry method. Totally, 23 compounds were identified in sound beech wood which most of these compounds, in this temperature, are related to 2,6-dimethoxyphenol and 3-hidroxy-4-methoxy benzoic acid; and 31 compounds were detected in decayed beech wood that most of them are related to Cyclononasiloxane octadecamethy and 4-(3,4-Dimethoxybenzylidene)-1-(4-nitrophenyl) and also 17 compounds were detected the same in sound and decayed wood.
Ahmad Jahan latibari; Reza Jamail; Mehran Roohnia
Abstract
The influence of different dosages of surfactant and soap in the deinking of wastepaper is investigated. The results showed that the dosage of 0.25% soap generated highest brightness and lowest opacity. However, the dosage of 0.75% soap produced highest tensile and burst strength and 0.5% soap produced ...
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The influence of different dosages of surfactant and soap in the deinking of wastepaper is investigated. The results showed that the dosage of 0.25% soap generated highest brightness and lowest opacity. However, the dosage of 0.75% soap produced highest tensile and burst strength and 0.5% soap produced the lowest spec (dirt) index. In the case of surfactant application, the dosage of 0.75% surfactant produced highest brightness and 0.5% surfactant generated lowest opacity. Application of 0.5% surfactant showed highest tensile and burst strength and lowest dirt index. The combined effect of both chemicals showed that the combined dosage of 0.75% surfactant and 0.25% soap produces highest brightness but the dosage of 0.25% surfactant without soap produced lowest opacity. Highest tensile and burst strength was related to pulp deinked using 0.5% surfactant and 0.75% soap. The results indicated that the combination of 0.75% surfactant and 0.25% soap generated highest brightness which the important property of the writing and printing paper. The highest tensile and burst strength was measured in deinked pulp produced using 0.5% surfactant and 0.75% soap.
Sohil Amiri; Ahmad Jahan latibari; Seid Javad Sepidehdam
Abstract
Old corrugated container (OCC) recycling generates large volume of effluent which is heavily loaded with pollutants. Its treatment is very difficult and complicated due to the presence of various pollutants and certain chemical with complicated structure. In this study, the treatment of OCC recycling ...
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Old corrugated container (OCC) recycling generates large volume of effluent which is heavily loaded with pollutants. Its treatment is very difficult and complicated due to the presence of various pollutants and certain chemical with complicated structure. In this study, the treatment of OCC recycling effluent using nano TiO2 was investigated and the treated effluent parameters such as COD, TDS, TSS, TS, EC and turbidity were measured. Nano TiO2 was applied at 0.5%, 1%, 1.5% of the effluent volume and the pH was adjusted at either 5, 9 or 7.3 (as received from mill). The results showed that the nano TiO2 and pH are effective on all of the parameters and the effect was statistically significant at 99%, but the effect of variables on EC was not measured statistically significant. The effect of pH on all of parameter was statistically significant at 99% expect on EC. Optimum condition was pH=9 and the dosage of nano TiO2= 0.5% and 1%. At this treatment condition, COD, TDS, TSS, TS and turbidity were reduced by 47.5, 38.7, 98, 70.4, and 97.7 % respectively
Physics and Mechanical Wood
Ehsan Haji rafiriha; Mehran Roohnia; Ahmad Jahan latibari; Ajang Tajidini
Abstract
The effect of lamination and adhesive coverage rate in layered products made from Poplar wood was studied The effect of lamination and adhesive coverage rate in layered products made from Poplar wood was studied by non-destructive free vibration test. 120 samples with nominal dimensions of 2.5×2.5×45 ...
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The effect of lamination and adhesive coverage rate in layered products made from Poplar wood was studied The effect of lamination and adhesive coverage rate in layered products made from Poplar wood was studied by non-destructive free vibration test. 120 samples with nominal dimensions of 2.5×2.5×45 cm without any obvious deficiencies were selected and free flexural vibration in free-free bars were performed for testing them. Samples were longitudinal cut in three thinner tangential layers and jointed together again using Poly Vinyl Acetate glue. The specimens were divided into four groups according to adhesive coverage rates, which one group was fully glued and 3 groups were carrying some glue deficiencies in different rates. Manipulated samples were tried again in above mentioned test. Results indicated that shear moduli compare to modulus of elasticity is a more sensitive parameter to evaluate glue efficiency in laminated beams but concerns remained due to blind points in flexural vibration nondestructive method.
Hanieh Ghasemi; Ahmad Jahan latibary; Mehran Rohnya; Mostafa Kohan torabi
Abstract
The effect of the application of different contents of canola particles in the production of particleboard on its acoustic properties were determined using free vibration on free-free bars procedure. 33 samples from each combination of canola and wood particles were prepared and the acoustical properties ...
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The effect of the application of different contents of canola particles in the production of particleboard on its acoustic properties were determined using free vibration on free-free bars procedure. 33 samples from each combination of canola and wood particles were prepared and the acoustical properties were determined. Results showed that as the content of canola particles in the mixture of the particles increases, the modulus of elasticity and acoustic coefficient of boards increases from 1260 MPa and 2.34 m4/s.kg to 1560 MPa and 2.54 m4/s.kg respectively. At the lower content of canola particles in the particles mixture, because of inhomogeneity, damping factor increased but by increasing the content of canola particles more homogeneous boards was obtained and damping factor decreased. Also, results showed that significant increase in acoustic coefficient efficiency was reached by increasing the content of canola particles. Therefore as the results revealed, incorporating more canola particles in the particleboard mixture, acoustic properties of particleboard improves and the product can be used in acoustic environments, halls and etc.
Amir Zamani; Ahmad Jahan Latibari; Aghang Tajdini; Abolfazl Kargarfard
Abstract
In this investigation, the surface chemical properties of the beech wood layers were characterized and the impact of drying condition on the strength of the bond was examined. Defect free beech logs were harvested and then the layers were prepared. The moisture content of the specimens were adjusted ...
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In this investigation, the surface chemical properties of the beech wood layers were characterized and the impact of drying condition on the strength of the bond was examined. Defect free beech logs were harvested and then the layers were prepared. The moisture content of the specimens were adjusted at 30, 40 and 50% (dry basis) and then the specimens were air dried under the environment of 30% relative humidity and 21ºC to reach the equilibrium moisture content of about 10% (dry basis). The pH and buffering capacity of the surface layer and the layer 0.5 mm underneath the surface were measured. The dried specimens were bonded using urea-formaldehyde resin and the tensile strength and wood failure were measured using relevant ASTM method. The results showed that as the moisture content prior to air drying was increased, the tensile strength was reduced, but the effect of this variable on tensile strength was not statistically significant. However, the effect of moisture content on wood failure was statistically significant at 99% significance level. The effect of the pH of the under layer on both tensile strength and wood failure was statistically significant at 95%. As the moisture content of the wood increased, the pH of the surface layer increased and the strength of the bond with urea-formaldehyde resin was deteriorated. At higher initial moisture of the wood, the alkaline buffering capacity of the surface layer was lower and its effect of the strength was not statistically significant, but it was significant on wood failure at 99% level. The alkaline buffering capacity of under layer was also changed and statistically affected the bond strength and wood failure at 95% level. The higher alkaline buffering capacity of the under layer adversely affected the tensile strength of the bond. The lowest acid buffering capacity was measured from specimens with 40% initial moisture content and as the acid buffering capacity was increased, the tensile strength was reduced and the wood failure was higher. The impact of surface layer acid buffering capacity on tensile strength was on statistically significant, but on wood failure was statistically significant at 99% level.
Porya Rezaei niaraki; Ahmad Jahan Latibari; Azhang Tajadini; Mehran Roohnia
Abstract
The influence of fiber lignin content and the dosage of coupling agent on the strength and physical properties of cellulosic fiber-polypropylene composite were investigated. The old corrugated container (OCC) fibers were delignified using sodium hydroxide to reach the lignin content of 2.7, 3.78, 5.26 ...
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The influence of fiber lignin content and the dosage of coupling agent on the strength and physical properties of cellulosic fiber-polypropylene composite were investigated. The old corrugated container (OCC) fibers were delignified using sodium hydroxide to reach the lignin content of 2.7, 3.78, 5.26 and 7%. Fibers were compounded with polypropylene by extrusion process using 20% fibers and 77% PP and the extrudate was cooled and grinded to fine granulates before injection molding. MAPP coupling agent was applied at three different levels (1, 2 and 3 percent based on the total weight of the composite). The strength properties of the composites were measured using relevant ASTM test methods and the results were statistically analyzed using factorial experiment under complete randomized design. The impact of fiber lignin content of flexural strength of composite was statistically significant at 98 percent significance level and the lowest and highest values of flexural strength of composite were measured at 3.78 percent and 7 percent lignin content of fiber. The interactive effect of fiber lignin and MAPP on the tensile strength and flexural modulus of elasticity of the composite showed that at lower values of lignin and higher dosage of MAPP, these properties are 38.7 and 3438 MPa respectively. Other strength values of the composites were also improved and at lower content of lignin and increaing dosages of the MAPP, the impact strength of the composites was increased from 52.82 J/m to 60.26 J/m.
Azhang Tajdini; Amir hossein Taghadosi; Shadman Pourmousa; Ahmad Jahan-Latibari; Vahid reza Safdari
Abstract
Abstract: In the recent years due to the innovations taking place in the production, packaging and shipping of furniture, world trade of these products has grown substantially. This issue along with some outstanding problems in manufacturing and marketing various kinds of wooden has caused that furniture ...
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Abstract: In the recent years due to the innovations taking place in the production, packaging and shipping of furniture, world trade of these products has grown substantially. This issue along with some outstanding problems in manufacturing and marketing various kinds of wooden has caused that furniture imports to Iran has enjoyed significant growth .In order to achieve the efficient and economic import, identify all factors that the perspective of experts led to prefer these products in compared with similar domestic production will be essential, therefore in this research in order to investigate the reasons for the expansion of the import quantities, the standardized questionnaires (certified by professionals and academic professors in four groups: Economics, Environment, Technical and Technological, and Consumption) are provided by use of documentary and survey research methods to investigate the effective indices on importing wooden furniture to Iran in order to describe the reasons of its widespread throughout Iranian experts. These main indexes indices of imports are rated by three methods: Likert spectrum, Duncan Test, and relative importance ratio of each index. We applied Likert spectrum on the whole statistical population and it shows that Environment index holds the first rank and Consumption, Technical and Technological, and Economics indexes are followed respectively. Duncan test shows Economics index has the first rank, Environment index holds the second place. Technical and Technological index are in the same place as Consumption index and according to the test there is no meaningful differences between them. On the other hand, using the relative importance ratio method we classified related occupations into 4 groups: producers, vendors/ distributers, importers, and consumers. We employed third method to see how these four groups evaluate the importance of each index. Results are as follows: PRODUCERS believe that Environment index is in the first place and then Economics, Technical and Technological, and finally Consumption index. VENDORS/DISTRIBUTORS believe Consumption, Technical and Technological, Economics, and Environment index is the sequence. IMPORTERS believe that Consumption index is in the main priority and then Technical and Technological, Economics, and Environment hold next places.
Sina Modirrahmati; Ahmad Jahan-Latibari; Mansor Minaei
Abstract
The influence of nanoclay addition on the strength properties of HDPE/ Wheat straw powder Composite was investigated. Composites compounds were produced using 73%HDPE, 25% wheat straw powder and 2% MAPE and three amounts of nanoclay (1, 2, and 3% of composite compound). First, HDPE and nanoclay was melt- ...
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The influence of nanoclay addition on the strength properties of HDPE/ Wheat straw powder Composite was investigated. Composites compounds were produced using 73%HDPE, 25% wheat straw powder and 2% MAPE and three amounts of nanoclay (1, 2, and 3% of composite compound). First, HDPE and nanoclay was melt- mixed and after cooling, the extrudate was milled to fine granules. This granules were then melt compounded with pre-weighted amount of wheat straw powder and MAPE followed by injection moulding to produce test specimens. The flexural, tensile and impact strength were measured. The results showed that the addition of nanoclay to the composite improved flexural strength and modulus, tensile strength and modulus. However the notched Izod strength was reduced.
Alireza Asgari; Ahmad Jahan latibari; Seiad Javad Sepidedam
Abstract
The impact of Multi Wall Carbon Nano Tubes addition on mechanical properties, water absorption and thickness swelling of polypropylene/old corrugated container (OCC) fiber composites was investigated. Polypropylene/ OCC fiber composite was prepared using 30% OCC fiber, 67% polypropylene and 3% MAPP. ...
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The impact of Multi Wall Carbon Nano Tubes addition on mechanical properties, water absorption and thickness swelling of polypropylene/old corrugated container (OCC) fiber composites was investigated. Polypropylene/ OCC fiber composite was prepared using 30% OCC fiber, 67% polypropylene and 3% MAPP. Three levels of multi wall carbon nano tubes (1, 2, 4% based on the weight of fiber/polypropylene/MAPP mixture) were added. Composite compound was prepared using a Haake mixer and the test samples were extruded. The results of strength measurement indicated that when 1 or 2% multi wall carbon nanotubes were added, Izod impact strength and flexural strength improved. Higher flexural modulus of elasticity was reached as either 2 or 4% multi wall carbon nano tubes was added. The performance of 4% multi wall carbon nano tubes on flexural modulus of elasticity was superior. Lower water absorption and thickness swelling levels were observed, as 1% multi wall carbon nano tubes was added.
