Ali Hasanpoor tichi; Hadi Gholamiyan
Abstract
In this study , Effect of nano cellulose Fiber gel bacteria as reinforcer on physical, mechanical and morphological properties of composites made of bagasse and cement has been studied. Nano variable factors in three levels (0, 1 and 3 % by weight of cement), the mixing ratio of bagasse as lignocellulosic ...
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In this study , Effect of nano cellulose Fiber gel bacteria as reinforcer on physical, mechanical and morphological properties of composites made of bagasse and cement has been studied. Nano variable factors in three levels (0, 1 and 3 % by weight of cement), the mixing ratio of bagasse as lignocellulosic material with Portland cement, in three levels (90:10, 80:20, 70:30%) was equal to the dry weight of cement. The target density 1.1 g/cm3 and 5% calcium chloride for all treatments were considered as Fixed factors. The mechanical and physical properties of composites includes modulus of rupture, modulus of elasticity, internal bonding, thickness swelling after 2 h and 24 h immersion in water and density of boards were measured according to the standard DIN-EN-634. In this study, to investigate the morphological properties of composites and how to distribute Nano, microscopic images (SEM) were taken from the broken cross-section of the samples. The results showed that boards made with nano fiber cellulose had more modulus of rupture, modulus of elasticity and internal bonding. The results also showed that with increasing nano, density, dimensional stability of the boards and heat hydration of cement mortar increased. The results from microscopic imaging (SEM) showed that cellulose nanofiber can fill the pores of the composite and create a uniform structure, thus improved the strength of the boards.
Behrouz Neyciyani; Majid Azizi; Behnam Gholampoor; Hadi Gholamiyan; Nemat Mohebi
Abstract
One of the most important economic goals of any state or economic system is to maintain a competitive position in every market. Competition in the market is ultimately improving the well - being of consumers and economic performance. Market analysis in order to resolve appropriate decisions by relevant ...
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One of the most important economic goals of any state or economic system is to maintain a competitive position in every market. Competition in the market is ultimately improving the well - being of consumers and economic performance. Market analysis in order to resolve appropriate decisions by relevant agencies requires recognition of its structure. In order to judge the extent of competition and monopoly on each market, the concept of Concentration is primarily used. Different indicators are used to measure the market concentration. This study was conducted with the aim of assessing the market concentration of Iran bedroom furniture and showing changes for the period from 1388 to 1397. In this regard, indicators of market concentration such as Concentration ratio, Herfindahl-Hirschman, Hall-Tiedman, Comprehensive concentration index and Hana-Kay were calculated. According to the results of the Herfindahl-Hirschman index, the furniture import market in this period is uncompetitive and the kind of monopoly of the firm and in 1396 year the market structure of a multi - lateral monopoly. According to the Hall-Tiedman Index, the market structure was a multi - faceted monopoly. Comprehensive index values of industrial concentration show a multi - sided monopoly market. The increase in the values of the Hana-Kay index has reached from 1388 to 1397, indicating a decline in the monopoly of the market. In general, in this regard, indicators of market concentration such as, Concentration ratio, Herfindahl-Hirschman, Hall-Tiedman, Comprehensive concentration index and Hana-Kay were calculated. The results show the existence of an oligopoly on the market. Monopoly has fluctuated with regards to the countries political-economic conditions in the mentioned period.
Hadi Gholamiyan; Ahmad Javid
Abstract
In this study, the effect of thermal cycle on surface degradation and crackability of wood coatings reinforced with clay nanoparticles and changes in adhesion and gloss properties were investigated. In this study, solvent-based coatings (alkyd, polyurethane), water-based coatings (chromium and phosphorescence) ...
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In this study, the effect of thermal cycle on surface degradation and crackability of wood coatings reinforced with clay nanoparticles and changes in adhesion and gloss properties were investigated. In this study, solvent-based coatings (alkyd, polyurethane), water-based coatings (chromium and phosphorescence) and oil-based coatings (oil-based coatings) were used in Abies alba wood species. Also, techniques and tests for measuring surface cracks, tensile adhesion and gloss meter were used to analyze the results before and after thermal fatigue. The results showed that the best coating performance in all three tests of tensile adhesion, surface gloss and surface crack is chrome coating and the most unsuitable of them is alkyd coating. Moreover, the results showed that the use of clay nanoparticles before the thermal cycle did not differ much in the properties of the coating, but after the thermal cycle increased the strength of the coatings. This increase in adhesion resistance in chromium, phosphorescence, oil, polyurethane and alkyd coatings was rate nearly doubled. In addition, the use of clay nanoparticles could reduce the crackability of the coating due to thermal fatigue and improve the performance of the coatings.
Mechanical conversion of wood and wooden fittings
Hadi Gholamiyan
Abstract
In this study, the effect of corona treatment on improving the durability of nitrocellulose and polyurethane coatings used in the wood furniture industry before and after weathering investigated. The boards made from poplar and beech were coated by an automatic film applicator after corona treatment ...
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In this study, the effect of corona treatment on improving the durability of nitrocellulose and polyurethane coatings used in the wood furniture industry before and after weathering investigated. The boards made from poplar and beech were coated by an automatic film applicator after corona treatment and accelerated for 30 days in a weathering machine. Then, the contact angle, abrasion resistance, and pull-off adhesion testing to the wood surface coatings were analyzed. The results showed that corona treatment reduced contact angle in wooden species and the highest contact angle reduction found in beech wood. Also, the results of the adhesion test showed that the highest adhesion was related to the polyurethane coating and after weathering, the adhesion of the coatings decreased, but the use of corona treatment, in addition to increasing the adhesion strength before weathering, could significantly improve adhesion after weathering. The results of the abrasion test showed that the wear resistance increased in wooden species due to the coating, and the highest amount observed in the beech-coated with polyurethane. After weathering, wear resistance was reduced in all samples, but using corona treatment increased resistance to abrasion. In general, it can say that the use of corona treatment can significantly (95%) improve the resistance to mechanical properties and durability of coatings before and after weathering and thus increase the durability of the furniture and wooden structures.
Management and Economics wood
Hadi gholamian; Asghar Tarmian; Ali Abdulkhani
Abstract
In present study, the adhesion strength of polyurethane and alkyd coatings on the poplar wood (Populus nigra) was improved by nano-silane coating using sol-gel method for outdoor application. For this purpose, the boards with dimensions of 15 × 10 × 2 mm were prepared according to EN 927-5. ...
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In present study, the adhesion strength of polyurethane and alkyd coatings on the poplar wood (Populus nigra) was improved by nano-silane coating using sol-gel method for outdoor application. For this purpose, the boards with dimensions of 15 × 10 × 2 mm were prepared according to EN 927-5. The surfaces of wood specimens were modified with Tetraethoxysilane (T) sol-gel material and then, solvent-borne alkyd (AS) and solvent-borne polyurethane (PS) coatings were applied. The coated samples were placed outdoor on a platform with a slope close to Karaj latitude (36̊) for 8 months according to ISO 877 standard. In order to characterize the quality of the coatings, colorimetric, tensile adhesion (Pull off), scratch adhesion (Cross cut) and ATR-FTIR tests were performed before and after weathering. The ATR-FTIR analysis demonstrated that the wood surface was covered with silicon oxides (SiO2) attached to hydrocarbon chains. As a result of surface wood modification by sol-gel, the color and adhesion strength of polyurethane and alkyd coatings were less affected by weathering. The highest tensile and scratch adhesions were found for the combined sol-gel and polyurethane coatings.
