TiNi alloy has a high resistance to wear and could be an excellent candidate for various tribological applications. But studies show that oxygen active elements can improve properties of some alloys, markedly. Yttrium...TiNi alloy has a high resistance to wear and could be an excellent candidate for various tribological applications. But studies show that oxygen active elements can improve properties of some alloys, markedly. Yttrium is one of the oxygen active elements. In this paper, the effects of yttria addition on properties of TiNi have been studied via micro-indentation, hardness, wear and corrosive wear tests. It is demonstrated that by addition of yttria to 5%, TiNi alloy can own improved mechanical properties and resistance to wear and corrosive wear.展开更多
TiNi alloy has a high resistance to wear and could be an excellent candidate for various tribological applications. In this paper, it was demonstrated that by addition of yttrium, hardness properties and resistance to...TiNi alloy has a high resistance to wear and could be an excellent candidate for various tribological applications. In this paper, it was demonstrated that by addition of yttrium, hardness properties and resistance to wear and corrosive wear of TiNi alloy were improved. New yttrium rich regions were formed in microstructure of TiNi alloy. The improved properties of this alloy by the yttrium addition could be attributed to the formation of these regions. The results showed that there was an optimum content for addition of yttrium between 2% and 5% （in wt%）, and above this content the improvement in properties of TiNi became minor.展开更多
Some physical and mechanical properties of cumin seed were obtained as moisture content changed from 7.24%to 21.38%d.b.Increasing of moisture content was found to increase the seed length(5.14-5.58 mm),width(1.33-1.55...Some physical and mechanical properties of cumin seed were obtained as moisture content changed from 7.24%to 21.38%d.b.Increasing of moisture content was found to increase the seed length(5.14-5.58 mm),width(1.33-1.55 mm),thickness(0.97-1.05 mm),arithmetic mean diameter(2.48-2.73),geometric mean diameter(1.88-2.09 mm),surface area(10.34-12.66 mm^(2)),thousand seed weight(2.9-3.9 g),porosity(51.22%-64.11%),true density(917.8-1030.6 kg/m3),static angle of repose(43-49 deg),dynamic angle of repose(47-56.6 deg),and coefficient of static friction on the three surfaces:glass(0.48-0.77),galvanized iron sheet(0.36-0.73),and plywood(0.57-0.69).However,bulk density was found to decrease from 447.66-369.88 kg/m3,and rupture force and rupture energy along with seed length and width were found to decrease from 83.74-56.17 N,132.95-84.47 N,50.66-27.52 mJ,and 67.8 to 33.36 mJ,respectively.The sphericity increased from 36.63%to 37.5%with increasing in moisture content from 7.24%to 14.5%d.b.and then reduced to 37.5%with further increase in moisture content to 21.38%d.b.展开更多
The goal of the modern farming systems is to economize energy consumption and to reduce farming costs.Proper selection and use of agricultural machines are important factors to achieve this end.Rotary tillers are till...The goal of the modern farming systems is to economize energy consumption and to reduce farming costs.Proper selection and use of agricultural machines are important factors to achieve this end.Rotary tillers are tillage tools that are used for accomplishment of both the primary and secondary tillage practices.Considering the widespread application of rotary tillers and wide use of modern tractors in Iran,optimal design of these machines is mandatory.Therefore in this study,the optimal working width and optimal diameter of the rotary tiller's rotor proportionate with the power of the MF 399 tractor was delineated based on the energy method.This theoretical method is based on the specific works of tractor and rotary tiller.Results showed that the optimal working width and optimal diameter of the rotary tiller’s rotor with maximum of forward speed 1 m/s for tractor was 240 cm and 6.27 cm,respectively.展开更多
Designing equipment for processing,sorting,sizing and other post-harvest operations of agricultural products requires information about their physical properties.This study was carried out to evaluate the effect of mo...Designing equipment for processing,sorting,sizing and other post-harvest operations of agricultural products requires information about their physical properties.This study was carried out to evaluate the effect of moisture content on some physical properties of barley grains.Four levels of moisture content ranging from 7.34%to 21.58%(d.b.)were used.The average length,width,thickness,arithmetic mean diameter,geometric mean diameter,thousand grain mass,sphericity,surface area and repose angle increased from 8.91 to 9.64 mm,3.30 to 3.74 mm,2.58 to 2.98 mm,4.93 to 5.45 mm,4.23 to 4.75 mm,44.48 to 51.30 g,47.55%to 49.35%,56.66 to 71.09 mm2 and 31.16°to 36.90°,respectively,as moisture content increased from 7.34%to 21.58%(d.b.).The bulk density,true density and porosity were found to decrease with increasing moisture content.The static friction coefficient of the grains increased linearly against various surfaces(plywood,glass and galvanized iron sheet)as the moisture content increased.At all moisture content,the maximum friction was offered by plywood,followed by galvanized iron sheet and glass surface.展开更多
基金support from Natural Science and Engineering Research Council of Canada(NSERC),University of Tehran and Tarbiat Modares University
文摘TiNi alloy has a high resistance to wear and could be an excellent candidate for various tribological applications. But studies show that oxygen active elements can improve properties of some alloys, markedly. Yttrium is one of the oxygen active elements. In this paper, the effects of yttria addition on properties of TiNi have been studied via micro-indentation, hardness, wear and corrosive wear tests. It is demonstrated that by addition of yttria to 5%, TiNi alloy can own improved mechanical properties and resistance to wear and corrosive wear.
文摘TiNi alloy has a high resistance to wear and could be an excellent candidate for various tribological applications. In this paper, it was demonstrated that by addition of yttrium, hardness properties and resistance to wear and corrosive wear of TiNi alloy were improved. New yttrium rich regions were formed in microstructure of TiNi alloy. The improved properties of this alloy by the yttrium addition could be attributed to the formation of these regions. The results showed that there was an optimum content for addition of yttrium between 2% and 5% （in wt%）, and above this content the improvement in properties of TiNi became minor.
文摘Some physical and mechanical properties of cumin seed were obtained as moisture content changed from 7.24%to 21.38%d.b.Increasing of moisture content was found to increase the seed length(5.14-5.58 mm),width(1.33-1.55 mm),thickness(0.97-1.05 mm),arithmetic mean diameter(2.48-2.73),geometric mean diameter(1.88-2.09 mm),surface area(10.34-12.66 mm^(2)),thousand seed weight(2.9-3.9 g),porosity(51.22%-64.11%),true density(917.8-1030.6 kg/m3),static angle of repose(43-49 deg),dynamic angle of repose(47-56.6 deg),and coefficient of static friction on the three surfaces:glass(0.48-0.77),galvanized iron sheet(0.36-0.73),and plywood(0.57-0.69).However,bulk density was found to decrease from 447.66-369.88 kg/m3,and rupture force and rupture energy along with seed length and width were found to decrease from 83.74-56.17 N,132.95-84.47 N,50.66-27.52 mJ,and 67.8 to 33.36 mJ,respectively.The sphericity increased from 36.63%to 37.5%with increasing in moisture content from 7.24%to 14.5%d.b.and then reduced to 37.5%with further increase in moisture content to 21.38%d.b.
文摘The goal of the modern farming systems is to economize energy consumption and to reduce farming costs.Proper selection and use of agricultural machines are important factors to achieve this end.Rotary tillers are tillage tools that are used for accomplishment of both the primary and secondary tillage practices.Considering the widespread application of rotary tillers and wide use of modern tractors in Iran,optimal design of these machines is mandatory.Therefore in this study,the optimal working width and optimal diameter of the rotary tiller's rotor proportionate with the power of the MF 399 tractor was delineated based on the energy method.This theoretical method is based on the specific works of tractor and rotary tiller.Results showed that the optimal working width and optimal diameter of the rotary tiller’s rotor with maximum of forward speed 1 m/s for tractor was 240 cm and 6.27 cm,respectively.
文摘Designing equipment for processing,sorting,sizing and other post-harvest operations of agricultural products requires information about their physical properties.This study was carried out to evaluate the effect of moisture content on some physical properties of barley grains.Four levels of moisture content ranging from 7.34%to 21.58%(d.b.)were used.The average length,width,thickness,arithmetic mean diameter,geometric mean diameter,thousand grain mass,sphericity,surface area and repose angle increased from 8.91 to 9.64 mm,3.30 to 3.74 mm,2.58 to 2.98 mm,4.93 to 5.45 mm,4.23 to 4.75 mm,44.48 to 51.30 g,47.55%to 49.35%,56.66 to 71.09 mm2 and 31.16°to 36.90°,respectively,as moisture content increased from 7.34%to 21.58%(d.b.).The bulk density,true density and porosity were found to decrease with increasing moisture content.The static friction coefficient of the grains increased linearly against various surfaces(plywood,glass and galvanized iron sheet)as the moisture content increased.At all moisture content,the maximum friction was offered by plywood,followed by galvanized iron sheet and glass surface.
