储藏期与储藏压力对稻谷籽粒压缩特性的影响研究
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摘要
利用质构仪压缩稻谷籽粒的短轴来测定稻谷籽粒的压缩特性。测定的稻谷储藏在不同的时间与压力下。实验结果表明:当储藏时间为60 d且储藏压力由0 kPa增加到300 kPa,稻谷籽粒的破坏力由81.6 N减小到73.8 N,破坏能由8.10 mJ减小到6.27 mJ,破坏应变由0.139减小到0.117,表观接触弹性模量由171.3 MPa减小到57.7 MPa,最大接触应力由40.8 MPa减小到19.1 MPa。当稻谷储藏压力为77、100、139、200 kPa且储藏时间由0～60 d,稻谷籽粒的破坏力由81.6 N分别减小到79.6、79.1、78.2、77.0 N;破坏能由8.10 mJ分别减小到7.55、7.35、7.08、6.85 mJ;破坏应变由0.139分别减小到0.131、0.128、0.126、0.121;表观接触弹性模量由171.3 MPa分别减小到136.0、121.8、110.6、83.3 MPa;最大接触应力由41.2 MPa分别减小到35.0、32.5、30.3、15.0 MPa。结果表明储藏压力与储藏时间对稻谷籽粒的压缩特性有重要的影响。
The compression characteristics of rice grains were measured by compressing short axes of rice grains with a gravimeter.The paddy grains were stored under different pressures and for different time.The results showed that as the storage pressure increased from 0 to 300 kPa,the rupture force of paddy grains stored for 60 decreased from 81.6 to 73.8 N,the rupture energy from 8.10 to 6.27 mJ,the rupture strain from 0.139 to 0.117,the apparent contact modulus of elasticity from 171.3 to 57.7 MPa and the maximum contact stress from 40.8 to 19.1 MPa.All of the compression characteristic of the paddy grains exhibited a linear relationship with storage pressure.As for the paddy grains stored under the pressures of 77,100,139,200 kPa,as the storage time increased from 0 to 60 days,the rupture force of the paddy grains declined from 81.6 to 79.6 N,81.6 to 79.1 N,81.6 to 78.2 N and81.6 to 77.0 N; the rupture energy fell from 8.10 to 7.55 mJ,8.10 to 7.35 mJ,8.10 to 7.08 mJ and 8.10 to6.85 mj; the rupture strain decreased from 0.139 to 0.131,0.139 to 0.128,0.139 to 0.126 and 0.139 to 0.121;the apparent contact modulus of elasticity fell from 171.3 to 136.0 MPa,171.3 to 121.8 MPa,171.3 to 110.6 MPa and 171.3 to 83.3 MPa; the maximum contact stress decreased from 41.2 to 35.0 MPa,41.2 to 32.5 MPa,41.2 to30.3 MPa and 41.2 to 15.0 MPa,respectively.The results revealed that both storage pressure and storage time have a significant influence on the compression characteristics of paddy grains.
The compression characteristics of rice grains were measured by compressing short axes of rice grains with a gravimeter.The paddy grains were stored under different pressures and for different time.The results showed that as the storage pressure increased from 0 to 300 kPa,the rupture force of paddy grains stored for 60 decreased from 81.6 to 73.8 N,the rupture energy from 8.10 to 6.27 mJ,the rupture strain from 0.139 to 0.117,the apparent contact modulus of elasticity from 171.3 to 57.7 MPa and the maximum contact stress from 40.8 to 19.1 MPa.All of the compression characteristic of the paddy grains exhibited a linear relationship with storage pressure.As for the paddy grains stored under the pressures of 77,100,139,200 kPa,as the storage time increased from 0 to 60 days,the rupture force of the paddy grains declined from 81.6 to 79.6 N,81.6 to 79.1 N,81.6 to 78.2 N and81.6 to 77.0 N; the rupture energy fell from 8.10 to 7.55 mJ,8.10 to 7.35 mJ,8.10 to 7.08 mJ and 8.10 to6.85 mj; the rupture strain decreased from 0.139 to 0.131,0.139 to 0.128,0.139 to 0.126 and 0.139 to 0.121;the apparent contact modulus of elasticity fell from 171.3 to 136.0 MPa,171.3 to 121.8 MPa,171.3 to 110.6 MPa and 171.3 to 83.3 MPa; the maximum contact stress decreased from 41.2 to 35.0 MPa,41.2 to 32.5 MPa,41.2 to30.3 MPa and 41.2 to 15.0 MPa,respectively.The results revealed that both storage pressure and storage time have a significant influence on the compression characteristics of paddy grains.
引文
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[12]AFKARI A H,GOLMOHAMMADI A,RASEKH M.Effect of variety,size and moisture content on modulus of elasticity and maximum contact stress of barley[J].Journal of Agricultural Engineering Research,2011,12(2):115-126.
[2]SUN X.Analysis of rice market in 2012 and the trend outlook in 2013[J].Cereals&Oils,2013,26(4):44-47
[3]BAGHERI I,DEHPOUR M B.Effect of moisture content and loading rate on mechanical strength of brown rice varieties[J].World Academy of Science,Engineering and Technology,2011,59:1385-1391
[4]LI Y B,CAO Q L,ZHONG Q X.Study on rough rice fissuring during intermittent drying[J].Drying Tech.,1999,17(9):1779-1793
[5]PRASAD S,GUPTA C P.Behavior of paddy grains under quasi-static compressive loading[J].Transactions of the ASAE,1973,16(2):328-330
[6]ALTUNTAS E,YILDIZ M.Effect of moisture content on some physical and mechanical properties of faba bean(Vicia faba L.)grains[J].Journal of Food Engineering,2007,78(1):174-183
[7]SADEGHI M,ARGHI H A,HEMMAT A.Physico-mechanical properties of rough rice(Oryza sativa L.)grain as affected by variety and moisture content[J].Agricultural Engineering International:CIGR Journal,2010,12(3):129-136
[8]ZAREIFOROUSH H,KOMARIZADEH M H,ALIZADEH M R.Mechanical properties of paddy grains under quasi-static compressive loading[J].New York Science Journal,2010,3(7):40-46
[9]ASAE Standards 2001b.Moisture measurement-unground grain and seeds[S].American Society of Agricultural Engineers,2001,567-568
[10]KOSMAN A,CUNNINGHAM H.Table for calculating the compressive surface stress and deflections in the contact of two solid elastic bodies where principal plans of curvature do not coincide[J].Journal of Industrial Mathematics,Detriot,MI,1962,12(1):31-40
[11]陆琳琳.高大平房仓内粮食摩擦与压缩特性研究[D].南京:南京财经大学,2011LU L L.Experiment study on friction and compression characteristics of grain in the large horizontal ware house[D].Nanjing:Nanjing University of Finance and Economics,2011
[12]AFKARI A H,GOLMOHAMMADI A,RASEKH M.Effect of variety,size and moisture content on modulus of elasticity and maximum contact stress of barley[J].Journal of Agricultural Engineering Research,2011,12(2):115-126.