مسعودرضا حبیبی

This study was carried out to investigate the effect of Bagasse alkaline treatment (hydroxide sodium) on Medium Density Fiberboard (MDF) properties. For this purpose, wet depitted and storage bagasse was used. Cooking process was done for fibers preraring in 10 liters digester. Liqure to bagasse ratio was 10 to 1. Hydroxide sodium content was 0%, 4% and 5% based on oven dry weigth of bagasse. Cooking time and temperature were 5 min and 170 centigrade respectively. Fiber slides were obtained by using optical microscope. Chemical components such as holocelloulose and lignin contents were determined. Liqures pH was mesearued before and after cooking. Urea formaldehyde resin was used for MDF producing. Resin content was 12% based on oven dried bagasse. Bending properties (MOR & MOE), internal bonding and thickness swelling of the boards were determined based on EN-310, EN-319 and EN-317 respectively. The results showed that when using 4% alkaline treatment, were seen the minimum fibers cutting and crusing. With increasing of hydroxide sodium content, lignin content decreased and holocelloulose increased. Bulk density increased when increasing hydroxide sodium content. The maximum MOR, MOE and internal bonding of the boards were obtained in 4% hydroxide sodium content. Also thickness swelling of the boards was minimum.

In this study, the effect of piling storage method of Bagasse was studied on the physical and mechanical properties of particleboard. Wet depitted Bagasse was used. In this study, Bagasse storage conditions included two moisture content (45% and 55%) and 4 storage times (1.5, 3, 4.5, 6 months). At the first, Bagasse chemical properties (pH, acid and alkaline buffering capacity) were determined. Then particleboards were fabricated. The physical and mechanical properties of the boards were measured and statistically analyzed. The results showed that at lower Bagasse moisture content, the sample pH and alkaline buffering capacity were decreased and acid buffering capacity increased. Also board bending properties (modulus of rupture and modulus of elasticity) and thickness swelling after 2 and 24 hours immersion in the water were reduced. Bagasse chemical properties tend to be acidic up to storage time of 3 month and the minimum of board bending properties and internal bond were obtained in this storage time. The physical properties of boards were improved with increasing of storage time.

The purpose of this study was to use of Hemp stalks in particleboard production. Mixtures of Hemp stalk and Eucalyptus wood at the ratios of 0:100, 50:50, 100:0 were used. Also two resin content of 8 and 10% (based on oven dry particle) and 2 press times of 3 and 4 minutes were employed for the production of laboratory particleboard. Physical and mechanical properties including thickness swelling after 2 and 24 hours soaking in water, modulus of rapture, modulus of elasticity and internal bonding were measured data were statistically analyzed. It was observed that the increase in Hemp stalk particles in the mixture resulted in increasing of bending properties (bending strength and modulus of elasticity) and thickness swelling after 2 and 24 hours water soaking. Also the results showed that increase in Hemp stalk particles in the mixture resulted in reduction of internal bonding. As expected, physical and mechanical properties of particleboard improved with increasing resin content. Modulus of elasticity and thickness swelling after 24 hours water soaking were improved with increasing of press time. In general, comparing the produced board mechanical properties with standard of Iran requirements, the board produced using 100% and 50% Hemp stalk, 8% resin content and 3 minutes press time showed that optimal properties. Although the physical properties of the boards did not meet the standard values, the reason for this could not be due to the lack of use of paraffin.

This study was carried out to investigate the effect of storage time and moisture content of bagasse on the physical and mechanical properties of particleboard. For this purpose, wet depitting bagasse was used and samples were maintained in bailing storage method. In this study, was applied 4 storage times (1.5, 3, 4.5 and 6 months) and 2 moisture content of Bagasse (45% and 55%). According to these variables, particleboards were made. Also chemical properties (pH, acid and alkaline buffering capacity) of Bagasse were determined. The mechanical and physical properties of the boards were measured and statistically analyzed using factorial experiment and complete randomized design. Then Duncan multiple range test was used for grouping of the averages. The results revealed that with decreasing of Bagasse moisture content, Bagasse sample pH and acid buffering capacity were decreased and increased, respectively. Also bending properties and thickness swelling after 24 hours immersion of the boards were improved. With increasing of storage time, the chemical properties of Bagasse tend to be alkaline, and the minimum of board internal bond strength was obtained in 1.5 month storage time. The physical properties of boards were improved with increasing of storage time

The benefits of wind power generation have led to an ever-increasing expansion of wind farms around the world. The low cost of production and the environmental benefits of wind farms are some of the main reasons for using wind energy. On the other hand, uncertainty costs in the production and control of the output of wind turbines are among the problems that are being encountered for electricity operators and markets. One of the basic measures to increase the penetration of wind power is to study the effects of this penetration on the restructured power grids. In this study, the effects of wind power plants on the market price and power system reliability in generation sector is evaluated in the one-year period.  The proposed method is tested on IEEE-RTS 24 bus network and it will be tried to obtain more realistic results compared to the market and reliability of the network, taking into account the different Reserves percentage and price elasticity of demands. In simulations, the effect of network reservation uncertainty is considered. Also, Monte Carlo simulation is used for wind modeling. This study attempts to compare the results of adding and replacing wind power producers in the grid to assess the changes in the system reliability and market efficiency. The results indicate a positive effect of concurrency of allocation of reserves and proposed schemes on reliability and market efficiency.

In this study, the effect of mixing method and nanoclay content on the physical, mechanical and morphological properties of wood plastic composite (WPC) were evaluated. Wood plastic composites were produced from recycled polyethylenes (low and high density) mixture, nanoclay and wood flour. The matrix and wood flour content were 60 wt% (LDPE 34% & HDPE 26%) and 40 wt%, respectively. Also, nanoclay was added in two levels 0 and 3 wt%. Simultaneous mixing and premixing method were used to manufacture the samples. The melt premixing samples exhibited superior physical and mechanical properties compared to the samples made by simultaneous mixing method. The composites containing nanoclay exhibited higher water absorption and lower strength properties. The results also indicated nanoclay agglomeration and poor distribution in the polymer matrix. Compared with the simultaneous mixing method, better distribution has been found for nanoclay particles in the samples made from the premixing method.

Cereal straws including grain sorghum varieties can be used for pulp production due to the significant amount of residual straw after harvesting. This study showed that there are no significant differences between fiber dimension and papermaking coefficients of two varieties of sorghum (Kimia and Sepideh). The average of fiber length، fiber width، lumen diameter، and cell wall thickness were measured as 1. 19 mm، 23. 20، 15. 34، and 3. 93 µm، respectively. Significant difference (P < 0. 05) was found among all chemical composition of two varieties except lignin content. The average content of holocellulose، alpha-cellulose، lignin، extractive، and ash were determined as 62. 13%، 37. 71%، 21. 05%، 9. 58% and 6. 97%، respectively. The result revealed that pulp strength produced from Sepideh variety was better. However it requires more intense delignification compared to Kimia variety. The highest screen yield (33. 19%) was reached applying the treatment combination of 170°C، 12% NaOH، and 75 minutes from the Sepideh variety. Sorghum pulp could be combined with the virgin pulp to compensate cellulose raw material shortage in paper industry.

Paper industry has been experiencing growing shortage of cellulosic material over the last decades. As a fast-growing plant, kenaf has good potential to compensate wood shortages taking into account its long historical record of cultivation in Iran. Kenaf variety of 432 was collected from Varamin research station. Kenaf stalk yield was determined roughly as 10.5 air-dried metric tonnes (ADMT) per hectare for a single crop rotation. Soda pulping of core, bast and their mixture were carried out at three weight percent ratios of 50:50, 40:60 and 30:70. H-factor for the delignification process was adjusted about 800 using cooking treatment combination of 175 °C, 30 min, 18% sodium hydroxide, and 5:1 liquor to raw material ratio. Under similar cooking condition, yield and kappa no. of soda pulp prepared from the mixture of kenaf core and bast showed highest yield and kappa number. Kappa no. decreased with increasing bast fiber percent from 50% to 70%, and required increased PFI revolution to achieve certain freeness. Handsheet properties including thickness, breaking length, burst and specially tear index increased at higher bast fiber content.

Licorice root residue, a non wood lignocelullosic raw material produced following extraction process was investigated for medium density fiberboard production. MDF was produced utilizing fiber generated applying three steaming times (15, 20 and 25 minutes) at 170 °C steam temperature. The fibers were blended with 10 or 12 % urea formaldehyde resin and then the fiber mats were pressed for either 5, 6 and 7 minutes. Eighteen combinations of variables were obtained and for each combination, three boards and a total of 54 were produced. The anatomical characteristics of the roots and physical and mechanical properties of MDF including bending strength and modulus of elasticity, internal bonding and thickness swelling after 2 and 24 hours immersion in water were measured. The results revealed that the average fiber length and diameter of the root fibers were 1.02 mm and 11.63 µm respectively. The maximum bending strength, modulus of elasticity, internal bonding of the boards produced using fibers generated after 20 minutes steaming time, 7 minutes pressing and 10% resin were measured as 5.291 MPa. 559.4 MPa. and 0.1245 MPa., respectively. The minimum thickness swelling after 2 and 24 hours immersion in water of the above mentioned boards were 31.6% and 34.12% respectively. The results indicated that the fiber produced from licorice root can be used as a partial substitute in MDF production

In this study, particleboard was produced using Mesquite (Prosopis juliflora) called Somr wood. Oven dry density of stem and branch wood was measured as 0.92, 0.72 g/cm3 whereas the bark weight percentage of stem and branch wood determined as 13.6 % and14 % respectively. The influence of raw material mixture (stem wood, branch wood, the blend of stem and branch wood, 50/50 w/w) and resin content 10% and 12 % (based on dry weight of the particle) on particleboard properties were investigated. Properties such as MOR, MOE, IB, thickness swelling after 2 and 24 hours immersion in water were determined according to EN standard. Except for MOE, the effect of raw material type on board properties was significant. Particleboards made from branch wood, had the highest MOR. Maximum IB was observed in boards made from the blend of stem and branch wood. With the exception of bending properties, the effect of resin content on all board properties was significant. Increasing the resin content improved board properties. The lowest value of thickness swelling after 2 and 24 hours immersion in water was obtained in particleboard made from stem wood.

In this study, particleboard was produced by eucalypt and poplar wood mixture. Variations were as follow: -Combinations of Eucalyptus and Poplar wood were (%100, %0), (%66.5, % 33.5), (%33.5, % 66.5) and (%0, % 100) respectively. -Resin content (%8 and %10) Physical and mechanical properties of boards such as MOR, MOE, IB, TS2 and TS24 were examined according to EN standard. The effects of various raw materials combinations on bending properties were significantly different. Maximum of MOE and MOR were observed in %66.5 of Poplar wood and % 33.5 of Eucalyptus wood. As expected, Physical and mechanical properties of boards were improved by increasing of resin content. Results indicated that TS2 and TS24 were increased with increasing of Poplar wood in combinations. Also the lowest amounts of these properties were obtained in eucalyptus and poplar wood mixture of %100 and %0 respectively.

In this study Medium Density Fiberboard was produced from 4 year old Poplar clones (P.e. costanzo, P.e. 564.41, P.e. vernirubensis). Fibers length of P.e. costanzo, P.e. 564.41,. e. vernirubensis were measured 805, 751 and 764 micron respectively. Also fibers diameter of these clones were determined 25.76, 25.44, 25.23 micron respectively. Three steaming times (5, 10, 15 minutes) were used for fibers preparation. Also three press times (3, 4, 5 minutes) and two resin contents (9%, 11%) were applied for MDF production. Thus physical and mechanical properties of boards such as MOE, MOR, IB and Thickness Swelling after 2 and 24 hours were investigated. The physical and mechanical properties of boards were tested in based on EN standard. The measurements of bending properties and IB of MDF revealed that increasing steaming time caused to decrease MOE, MOR and IB. The highest of MOE, MOR and IB were obtained in 5 minutes steaming time. Also the lowest values of Thickness Swelling after 2 and 24 hours were obtained in 15 minutes steaming time. The influence of press time on bending properties was not significant. The highest of IB was obtained in 5 minutes press time. As expected, boards demonstrated better properties at higher resin content.

In this study, MDF was produced from three clones of poplar (P.e. vernirubensis, P.e. costanzo, P.e.561.41). Age clones of poplar were 4 and 12 years. In addition to age variation, the influence of three production variables (steaming time, press time and resin content on MDF properties were investigated. Variations of each variable were as follow:- Steaming time (5, 10, 15 minutes)- Press time (3, 4, 5 minutes)- Resin content (9%, 11%)Fiber length and fiber diameter of 4 and 12 years old poplar clones (P.e. vernirubensis, P.e. costanzo, P.e.564.41) were measured 746, 25.23, 805, 25.76,751, 25.44 and 902, 31.62, 995, 29.23, 899, 26.83 micron respectively.MOR, MOE, IB, TS2, TS24 were determined according to DIN standard.Increasing steaming time decreased board's internal bond and bending properties. As expected, boards demonstrated better properties at higher resin consumption. Minimum of boards thickness swelling were obtained at 15 minutes steaming time because of fiber hydrophilic properties were decreased. There are no significant differences between 4 and 12 years old of clones for bending properties and IB of boards. The effect of age variation is only significant difference on thickness swelling of boards which it is lower for 4 years old clones.

In this study the effect of two variables, (resin content and press time) on properties of MDF was investigated. Levels of each variable was as follow: Resin content (8, 9.5, 11 percent) Press time (4, 5, 6 minutes). The statistical analysis proved that the effect of press time on MOE and MOR was significant. MOE and MOR were the highest at press time of 6 minutes. According to Duncan's test, there aren’t any significant differences between MOE at press time of 5 and 6 minutes. Also the effect of resin content on MOE had significant differences. MOE was the highest at resin content of 11%. There aren’t any significant differences between MOE on resin content at 9.5% and 11% levels. The results showed that effects of press time and resin content had significant differences on IB. IB was the highest at press time of 6 minutes and resin content of 11%. There aren’t any significant differences between IB on resin content at 9.5% and 11%. The effects of press time and resin content had significant differences on thickness swelling after 2 hours. Thickness swelling was the lowest at press time of 6 minutes and resin content of 11%. According to the results of this study optimum combination for MDF production from baggasse includes resin content and press time of 9.5% and 5 minutes respectively.

In this study, MDF was produced from wet depicting Bagasse in three steaming time of 5, 10 and 15 minutes and in two steaming temperatures of 170°C and 180°C. There were 6 treatment conditions by combination of the above factors and three replications for each combination which resulted in producing 18 boards.The anatomical and chemical properties of Bagasse and also the physical and mechanical properties of MDF such as MOR, MOE, IB and swelling thickness after 2 and 24 hours were studied.Fiber length, fiber diameter, lumen cell diameter, and cell wall thickness were respectively measured 1.24 mm 22.90m., 12.48 m and 5.28m cellulose, lignin, extractives, and ash contents were 53.68%, 20.44%, 0.96% and 1.14% respectively.The measurement of MOR, MOE, IB and SW (after 2 and 24 hours) of the MDF revealed that the proper condition is obtained at the steaming temperature of 170°C and the steaming time of 5 minutes. The properties in the above-mentioned conditions were measured 12.22Mpa, 1370 Mpa, 0.13 Mpa, 47.11% and 52.22% respectively.