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测定了香榧和榧仁的外形尺寸、壳厚、壳与仁间隙、破坏载荷及变形等物理特性参数,并进行了分析.结果表明,香榧分级破壳时的分级数以4级、级差以1mm为宜;采用锲形滚筒挤搓方式破壳时,锲形滚筒变形间隙只要处在0.8~1mm,便可保证香榧破壳率和破碎率,满足生产要求. 相似文献
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针对目前油棕果壳破壳不完全和壳仁分离不彻底导致棕仁油提炼不纯的问题,基于敲击式破壳机理和摩擦分离原理设计一种小型油棕果壳破碎分离机,通过分析计算确定滚筒的几何参数,打击机构的压缩弹簧的自由长度为95 mm、有效圈数为11圈以及分离机构的传送带与水平面的夹角为20°。利用含水率为14%,横向长度为15~17 mm,纵向长度为17.5~20 mm的油棕果壳进行破碎分离试验,试验结果:脱壳率为88.2%、分离率为79.7%。 相似文献
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针对扁桃脱壳装置存在脱壳不完全、脱壳率低的问题,对扁桃脱壳机在脱壳取仁过程中果壳加载损伤进行分析,确定挤压加载状态下脱壳区裂纹扩展及果壳分离的基本特点。根据薄皮扁桃物理特性试验及预试验结果,选取脱壳间隙、刚性辊转速、柔性带线速度作为试验因素,脱壳率和核仁破损率作为试验指标进行正交试验,试验样品为Ⅱ等级厚度 12~13 mm的扁桃。试验结果表明:脱壳间隙为11 mm,刚性辊转速为200 r/min,柔性带线速度为0.7 m/s,是该机具工作参数的最优组合。对该参数组合进行验证试验,脱壳率为97.68%,破损率为6.85%,满足生产要求,为扁桃精深加工奠定基础。 相似文献
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松籽壳体工程特性参数的测试与静力有限元计算 总被引:6,自引:0,他引:6
介绍了松籽壳体工程特性参数的测试方法和松籽三向尺寸、壳皮厚度、壳仁间隙与静滑动摩擦系数等测试数据,给出了籽壳含水率对破壳力的影响规律,认为沿Y向(松籽宽度方向)加载可减少籽仁破损率并能提高破壳生产率。还介绍了以等厚度椭球薄壳作为松籽壳体的计算模型,运用静力有限元法进行计算,得出与实测基本吻合的结论。 相似文献
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山核桃坚果有限元模型建立及受力分析 总被引:2,自引:0,他引:2
针对山核桃果壳完全破裂所需的变形量大于壳仁间隙,用一般的机械挤压方法破壳会造成大量碎仁等问题,利用Pro/E软件建立了山核桃的几何模型,采用有限元分析方法构建了山核桃破壳受力模型,并对山核桃进行了受力模拟与分析。根据不同受力方向和不同载荷下山核桃的应力应变分布情况,确定山核桃壳变形量不大且产生局部裂纹点多、裂纹点易扩展的最佳施力方式,为山核桃破壳取仁设备的研制提供依据。 相似文献
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《Journal of Agricultural Engineering Research》1998,69(3):249-254
A model to represent the discolouration of dried powder of carrots as a function of temperature was developed. Two types of carrots, Asian and European, containing large amount of lycopene and β-carotene, respectively, were tested. The dried powder was stored under an atmosphere with O2and at three different temperatures, 5,20 and 35°C. The surface colour of the powder was monitored during storage by a Hunter colour ratioa/b. In the proposed model, the rate of oxidation was assumed to be represented by the product of the fraction of concentration of oxidized pigment at arbitrary time and a specific rate of oxidation of pigment. The rate parameters in the proposed model were calculated by fitting the experimental data with smooth curves by trial and error at the end of the induction period but before discolouration took place. The frequency constant and activation energy, expressing the temperature dependence of the rate parameters, were expressed by the Arrhenius relation. The simulation results of a Hunter colour ratioa/bof dried powder at 25°C showed good agreement with the experimental data, suggesting that the proposed model was effective for the prediction of discolouration of dried powder of both types of carrot. The use of the induction period in the manner described may enable the shelf life of dried powder to be predicted. 相似文献
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感官检验棉花的品级,这是农村常见的一种检测手段.它的一个主要特点就是存在不确定性.这是由于检验员的品级检验水平存在一定的差异,其中有很多因素制约着检验的结果.文章对影响感官检验结果的因素进行了系统的分析. 相似文献
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The fractional outflow rate of water from the rumen, measured as the rate of disappearance of the chromium complex of ethylenediamine tetra-acetic acid, was related to a number of dietary factors. A multiple regression equation was derived which expressed fractional outflow rate as a function of the intakes of dry matter, ash, acid-detergent fibre and crude protein.The data analysed consisted of 243 observations for sheep on 59 diets, including forage, concentrate and mixed diets. The ranges covered by the data were: fractional outflow rate 0.7–3.6 day?1; dry matter intake 560–1400g/day; ash 4–30%, acid-detergent fibre 7–41%, crude protein 5–26 % of dry matter; there were no observations for sheep of less than 34 kg liveweight.The equation accounted for 56·3 % of the total variance. Between-sheep variance could not be calculated for the whole of the data but was undoubtedly substantial since, for a sixth of the data, it was known to account for 38 % of the total variance. 相似文献
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从灾害经济学的角度探讨了城镇供水优化调度的必要性和可能性,认为在缺水不可避免的情况下,对供水进行优化调度可以减小缺水带来的损失,产生较好的减灾效益,特别是可以大大减小严重干旱的灾害效应。并根据水资源的特性,提出了缺水损失的计算模式以及优化调度的原则和方法。 相似文献