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为提高梨酒专用酵母Saccharomyces cerevisiae DJ02的出酒率,通过单因素试验初步确定Saccharomyces cerevisiae DJ02的发酵条件为:装液量80mL、接种量(体积分数)11%、初始pH值5.5、培养温度20℃、发酵时间8d。探讨了陈皮等20种中药作为刺激因子对Saccharomyces cerevisiae DJ02的出酒率的影响,得出砂仁等6种中药对该菌体出酒率有显著的影响。采用Plackett-Burman试验和响应面分析法进一步优化了发酵条件及中药的添加量,得出最佳值为:培养温度22℃、装液量75.0mL、初始pH值5.71、发酵时间8d和砂仁体积分数1.0%,此时出酒率为16.92%,比优化前提高了 相似文献
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苹果切片红外辐射干燥模型建立与评价 总被引:1,自引:0,他引:1
选择加热温度为60℃,辐射功率为750W,辐射距离为100mm,物料厚度为5mm时的红外辐射干燥苹果切片试验数据作为实测值样本,基于Matlab软件,利用高斯-牛顿算法,对传统干燥模型进行非线性最小二乘数据拟合求解,确定干燥系数。通过决定系数R2、误差平方和(SSE)及均方误差的根(RMSE)等拟合优度评价指标对各种干燥模型进行评价。结果表明,用Modified Page equationⅡ模型能够更好地预测和控制苹果切片红外辐射干燥过程。 相似文献
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果蔬全供应链既具有业务环节繁杂、数据多源异构、利益角色众多等通用食品供应链特征,又具有风险演变趋势复杂、时效性要求强、存在突发新发风险等特性。为有效解决传统果蔬供应链监管方案存在的监管覆盖面不足、溯源效应周期长、各主体间协同效应差等问题,构建了基于区块链多链的果蔬全程全息信息管理模型,并进行了系统化验收。首先,在果蔬全程全息信息解析的基础上,构建基于多链的果蔬全程全息信息管理模型。然后,提出一种基于区块综合索引指数的果蔬信息快速检索方法,并设计了基于公证链的果蔬信息跨链安全交互机制。其次,基于长安链开源区块链平台设计并开发了果蔬全程全息信息管理原型系统。最后,进行了实验验证和系统案例应用分析。结果表明,本系统公开数据上链平均耗时为589.03ms,隐私数据上链平均耗时为708.59ms,公开数据查询平均耗时为26.87ms,隐私数据查询平均耗时为30.67ms。本文设计的基于多链的果蔬全程全息信息管理模型及系统在满足不同需求用户对于不同权限信息的上链和查询需求的同时,实现了对果蔬全程全息信息的穿透式监管,满足了企业对隐私数据的权限控制与安全共享需求,提高了果蔬信息检索效率,为果蔬全程全息信息管理模型开发提供参考与借鉴。 相似文献
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果树喷雾用圆盘风扇三维气流速度场数值模拟与验证 总被引:6,自引:1,他引:6
为研究用于果树风送喷雾的圆盘风扇气流速度场分布特性,采用k-ε紊流模型和稳态求解方法,设置合适的边界条件,对单、双风扇不同出口风速的气流速度场进行三维稳态数值模拟和试验验证。结果表明,双风扇同时送风时,在离两风扇中心1~3m的范围内,中心区域的风速明显小于两边的风速,在3~5m的范围内中心区域的风速和两边的风速相差不大。模拟值与试验值对比表明变化趋势一致,二者的拟合直线决定系数R2分别为0.8044和0.7957,所建模型可以比较准确地模拟风扇气流速度场的分布。 相似文献
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高压脉冲电场预处理果蔬可以提高果蔬冻干速率、降低能耗。但研究运用果蔬介电特性在线监测冻干水分变化时,需要考虑高压脉冲电场电参数对果蔬介电特性的影响。为此,针对高压脉冲电场作用果蔬细胞层面,分析了电参数对果蔬介电特性的影响,对果蔬生物组织等效电路模型和电参数对果蔬等效电容、等效阻抗等介电特性的影响等方面进行了综述分析及机理分析,为高压脉冲电场预处理果蔬工艺参数优化提供了参考。 相似文献
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油菜分段收获脱粒清选试验 总被引:6,自引:3,他引:6
对我国南方油菜分段收获割晒后的脱粒清选特性和脱粒清选参数进行了研究。通过在试验台上脱粒和清选正交试验,得出了分段收获捡拾脱粒机脱粒、清选部件形式和两组合理的工作参数。试验结果表明:脱粒分离夹带损失最小的优选参数组合为喂入量1.6kg/s、滚筒转速750r/min、脱粒间隙15mm、滚筒形式钉齿6排;影响脱粒分离夹带损失率的主次因素为滚筒形式、喂入量、脱粒间隙和滚筒转速。综合考虑清选损失率和含杂率最〖JP3〗小的优选参数组合为开度10mm鱼鳞筛、振动筛曲柄转速260r/min、离心风机转速860r/min、离心风机倾角15°;由模糊综合评价值的极差分析可得因素的主次排序为离心风机倾角、振动筛曲柄转速、筛片结构形式和离心风机转速。 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