فهرست مطالب kazem doosthoseini

This study was performed to analyze the energy consumption in bagasse production as one of the byproducts from sugarcane and greenhouse gas emissions (GHG) amounts from bagasse production and its bagasse based Medium Density Fiberboard in Iran. Related data for this study was collected by direct interview and filling out questionnaires using company managers and staffs in Karoon Sugarcane Agro-Industrial Company and LooheSabz Jonoob bagasse based MDF Factory for the years 2016 to 2019. Greenhouse gas emissions were assessed by SimaPro software and energy consumptions amounts were calculated by direct and indirect energy consumptions and energy equivalents. Total energy consumptions for bagasse production were 2436.75 and 1368.74 MJ ha-1 in plant and ratoon farms, respectively. Water for irrigation, diesel fuel consumption and nitrogen fertilizer had the largest share of energy consumption in sugarcane production. The total amounts of greenhouse gas emissions for bagasse production were attained as 221.87 and 99.11 KgCO2eq ha-1 in plant and ratoon farms respectively. Diesel fuel consumption, agricultural machineries and nitrogen fertilizer in plant farms and diesel fuel, phosphate and nitrogen fertilizers in ratoon farms had the highest share of emissions, respectively. Furthermore, the amount of greenhouse gas emissions for bagasse based - MDF production was gained as 780.53 KgCO2eq m3-1. Electrical energy consumption, urea formaldehyde resin and natural gas had the main share in total GHG emissions in bagasse based -MDF production.

This study aimed to fabricate the bilayer scaffold containing nanocellulose/poly (vinyl) alcohol (CNF/PVA) to evaluate its potential use as a mimic for skin tissue engineering. A continuous process of layer addition with two different concentrations of polymers by freeze-drying technique was used. FE-SEM analysis indicated that the obtained scaffolds had interconnected porosity and pore size, which increased in lower concentration of polymers. The scaffolds were also characterized by water uptake, mechanical properties and MTT assay. Lower concentration of polymers increased water uptake and decreased mechanical strength. The MTT assay results showed that these nanofibrous scaffolds meet the requirement as a biodegradable material for skin repair.

In this study, the possibility of three-layered oriented strand board production from hornbeam (Carpinus betulus L.) wood was evaluated. Two levels of press time (6 and 8 minutes) and three levels of press temperature (180˚C, 200˚C and 220˚C) were applied and 12 mm thick laboratory boards were made from hornbeam wood. The strands on the surface layers were aligned in the long direction of the board and the middle layer strands are cross aligned to the surface layers. In all treatments, board targeted density of 0/7 g/cm3 and mat moisture content of 7% and phenol-formaldehyde resin (PF) content of 7% based on the oven dry weight of the strands were kept constant. The mechanical and physical properties of the boards were measured as defined in relevant European standards test methods EN 300. The internal bound (IB) and thickness swelling (TS24) of boards were significantly improved as the press time increased from 6 to 8 minutes. The modulus of rupture (MOR) and internal bound (IB) and thickness swelling (TS24) were significantly improved as the press temperature increased from 180˚C to 220˚C. Overall results showed that the highest MOR and IB and the lowest TS24 were achieved at 8 minutes press time and 220˚C press temperature and all boards made from this mentioned conditions exceed the EN 300 standards for MOR, MOE, IB and TS24.

In this study, fibers recycled via two different methods; hydrothermal and ohmic heating were used to manufacture medium density fiberboard (MDF). The purpose of this study was to determine the effect of recycling method on practical properties (bending strength, modulus of elasticity, internal bonding and screw holding in edge and surface and thickness swelling after 24 hours water immersion) of the boards. Also, a morphological analysis was done to evaluate the influence of recycling process on fiber dimensions. Also the existence of UF residues were observed by SEM.
The results related to classification and dimension analyze of fibers confirmed the negative influence of recycling process on quality of fibers. Also degree of deterioration in hydrothermal recycling was higher than that of ohmic recycling due to sever condition of heating.
Furthermore, the results showed that recycling of MDF wastes via ohmic heating method resulted in better physical and mechanical propertied as compared to the hydrothermal method. Overall results showed that MDF panels made from recycled fibers via ohmic heating method exceed the minimum values required by EN standards (EN 622-5, 2006) for all properties except thickness swelling. About ohmic heating method, increasing the time of ohmic heating led to improving the practical properties of recycled MDF boards. It was observed by SEM that much more residues of cured UF resin adhesive were existed on the surface of recycled fibers via hydrothermal method. According to the results it can be said that ohmic heating method is a useful process for recycling the wastes of MDF.

One of the important parts in the wood and paper industry are synthetic resins used. Epoxy resins, such as polymers are widely used in various industries and industrial adhesives. That obtained the compound bisphenol A and epichlorohydrin. Bisphenol A of the epoxy resins in the formulation is obtained from the petroleum products, that these products are limited and exhaustible, expensive and cancer. The presence of bisphenol A, in the environment, can be a serious threat to human health and the environment. Research conducted in the field of bio-based epoxy resins such as Shakeri et al (2010) used to soybean epoxy resin in in strawboard. Tasooji et al (2010) compared to the base resin of formaldehyde and epoxy soybean resin were examined in straw boards. The aim of this study was to synthesis of bio based tannin epoxy acrylate and producing particleboard with them and evaluated the mechanical and physical properties.
In this study, for the production of three layer particle board with bio-based tannin epoxy acrylate resin, fine wood chips to the surface layer remind 20 mesh and coarse wood chips pass to 20 mesh that was used for the middle layer. In order to reduce the moisture in wood with a moisture content of 2.5%, the particles put auto temperature for 8 hours at 103°C, respectively. Commercial tannin extracted from the bark mimosa, which is brown and dry powder contains 82% monomers and oligomers is flavonoid chemistry of Silva France was prepared. For synthesis of bio based tannin epoxy acrylate resin, acrylic acid (99%), hydroquinone (99%) and catalyst 4- Diazabicyclo [2,2,2] octane was used Sigma-Aldrich Co. Glycidyl ether tannin reacted with acrylic acid and hydroquinone and catalyst at a temperature of 95 °C for 12 hours and tannins epoxy acrylate resin was prepared. Using Fourier transform infrared spectroscopy was investigated final structure of the resin. Then in a three-layer board was made with tannin epoxy acrylate resin, at press temperatures of 160 and 180 °C and press time for 5/5 and 7/5 minutes with a nominal density of 700 kg/m3 and mechanical and physical properties were measured such as flexural strength (MOR), modulus elasticity (MOE) and Internal bending (IB) according EN310 and EN319 standards and physical properties such as water absorption (WA) and thickness swelling (TS) (after 2 and 24 hours immersion in water), according to standard EN317.
Acrylic acid reacts with the glycidyl ether tannin, in place of epoxy groups, acrylic groups are causing ripple branches combined. FTIR results confirmed the presence of acrylic resin. The results showed that increasing press temperature and press time had positive effect on physical and mechanical properties have been made. Flexural strength with increasing temperature and time after 13/3 to 16/3 MPa, the modulus of elasticity of 2600 MPa and 3600 Mpa, IB from 0.4 to 0.8 increased. Because a rise in temperature and press time, due to faster evaporation and condensation of moisture and soften the particles in the beam better and better heat transfer to the middle layer and curing the resin in the middle layer board and increase the strength. As temperatures rise and the press time, the thickness swelling has decreased after 2 hours from 11% to 7% and after 24 hours from 17 percent to 12 percent. The water absorption has decreased after 2 hours from 25% to 17% and after 24 hours from 30% to 21% .

In this study, the effects of mat moisture content and press temperature on physical and mechanical properties of three layered oriented strand boards were evaluated. Two levels of mat moisture content 7% and 10% and three levels of press temperature 180 ˚c , 200 ˚c and 220 ˚c were applied and 12 mm in nominal thickness laboratory boards were made from mixture of three clones of ten-year-old hybrid poplar ( populous euramericana vernirubensis, p. e. I-214, P. e. 561/41) while the strands on the surface layers are aligned in the long direction of the board and the middle layer strands are cross aligned to the surface layers. In all treatments, board targeted density of 0/7 g/cm3 and press time of 8 min and phenol-formaldehyde resin (PF) content of 7% based on the oven dry weight of the strands were held constant. The mechanical and physical properties of the boards were measured as defined in relevant European standards EN 300 for OSB/1 and OSB/2. Overall results showed that all boards made from above mentioned conditions exceed the EN 300 standards for MOR, MOE, IB and TS24. The bending properties (MOR and MOE) of boards were significantly improved as the mat moisture content increased from 7 to 10%. The highest MOR was achieved at 10% mat moisture content and 220 ˚c press temperature and the highest MOE was achieved at 10% mat moisture content and 180 ˚c press temperature. The Modulus of Rupture (MOR) and Thickness swelling (TS24) were significantly improved as the press temperature increased from 180 ˚c to 220 ˚c. The lowest TS24 was achieved at 7% mat moisture content and 220 ˚c press temperature and the highest IB was achieved at 7% mat moisture content and 200 ˚c press temperature.

Bio-epoxy tannin resin was made from tannin reaction with epichlorohydrin in an alkaline environment, Fourier transform infrared spectroscopy of epoxy groups of glycidyl reaction of the tannins confirmed, and the epoxy number was 7.2 epoxy resin final. Straw boards with Bio-epoxy tannin resin, using two variable temperature (180 and 200 °C) and variable times (7.5 and 10 minutes) were made. Physical and mechanical resistances such as water absorption and thickness swelling (after 2 and 24 hours soaking appears in water), internal bond, modulus and flexural modulus measured and the boards were compared with the standard EN312-4. The results showed that straw boards made with 200 °C and 10 minutes of press time, had the highest level of physical and mechanical properties. All boards produced in this research work, mechanical properties for public use, in accordance with the standards of Europe to have. That has functional properties comparable to petroleum-based synthetic adhesives are made of particleboard.

In this study, the effect of different drying methods on cellulosic nanofibers and resulting composites investigated. Four methods were examined to dry nanofibrillated cellulose suspensions: air drying, oven drying, spray-drying and freeze drying. The particle size and morphology of the CNFs were determined via dynamic light scattering, scanning electron microscopy, and morphological analysis. Freeze drying formed ribbon-like structures of the CNFs with nano-scale thicknesses. Width and length were observed in tens to hundreds of microns. Spray-drying formed particles with a size distribution ranging from nanometer to several microns. Spray-drying is proposed as a technically suitable manufacturing process to dry CNF suspensions not only with dimension in nano range but also improving mechanical properties of poly (lactic acid) based composites.

In this study, the effect of bacterial nanocellulose, in three levels (control, powder and gel) as a reinforcement for fiber- cement composites was investigated. Also, 6 and 7 wt% of bagasse fibers were used for composite manufacturing. Mechanical and physical properties of composites including modulus of rupture (MOR), modulus of elasticity (MOE), fracture toughness (FT), internal bonding strength (IB), and ware absorption (WA) after 2 and 24h emersion in water were measured. Results showed that composites made with cellulose gel had higher bending strengths, internal bonding strength and fracture toughness. Combination of 7% bagasse fiber content and cellulose gel reduced water absorption of composites. In these composites, internal bonding was increased and less empty spaces remained for water penetration probably due to uniform distribution of fibers and cellulose gel within the cement matrix. XRD analysis showed that peaks corresponding to main hydration products such as CSH and calcium hydroxide had higher intensities in composites containing bacterial cellulose gel. Results obtained from freeze-thaw cycling test showed that composites containing cellulose gel had the higher internal bonding strength compared with other two composites after 20 cycles. In this study, fiber-cement composites produced from 7% bagasse fiber and bacterial cellulose gel have been selected as the optimum treatment.

In this study، the effect of nano-SiO2 in four levels of 0، 1، 2، and 3 percent (weight of cement) and the type of lignocellulosic materials on physical and mechanical properties of woodcement boards manufactured by old corrugated container (OCC) and rice husk have been investigated. Totally 8 treatments were taken that each one had three repetitions. Samples were provided according to DIN EN 634 and physical and mechanical properties، including modulus of rupture، modulus of elasticity، shear strength parallel to surface، hardness، water absorption and thickness swelling after 2 & 24 hours immersion in water، have been measured. The Results indicated that in case of using nano-SiO2، OCC-cement boards incorporating 1 percent and rice husk-cement boards incorporating 2 percent nano-SiO2 had the highest bending strength and modulus of elasticity. Shear strength parallel to surface and hardness were further in boards incorporating 2 percent nano-SiO2. Also، using rice husk in board manufacturing has decreased the water absorption compared to OCC.