薄层物料双面喷射式加料系统的研制与应用

为解决传统滚筒加料系统加料均匀性差、料液有效利用率低和物料粘附等问题,根据薄层物料双面加料更加均匀的原理,研制了薄层物料双面喷射式加料系统。该系统主要由松散均布、高速摊薄、双面多点喷射加料和过滤吸附等装置组成。通过对物料进行摊薄,形成稳定的物料帘,在物料帘的双面实施多点喷射加料,保证料液施加的均匀性;通过排潮抽吸风使悬浮的雾化料液穿过物料层,利用物料层的吸附过滤作用,提高料液的利用率;加料腔为不对称多孔罩式结构,使腔体内外气压保持平衡,减少物料与腔壁的接触。利用"黄金叶(硬帝豪)"对双面喷射加料和滚筒加料两种方式的加工品质、产品质量、主流烟气成分和能耗物耗进行对比试验。结果表明,与滚筒加料方式相比,采用薄层物料双面喷射加料方式,加料精度为0.08%,加料均匀系数提高1.69百分点,料液有效利用率提高13.7百分点,物料粘附量减少4.1 kg/批次;卷烟感官质量提高0.5分;综合加工成本节约6.97元/箱。该系统有效提高了片烟加料的均匀性和料液有效利用率,避免了物料粘附现象,改善了卷烟感官质量,节约了能源和原材料消耗。      

白肋烟叶片、叶丝二次加料研究

为解决白肋烟加料过程中存在的加料均匀性差、料液有效利用率低等问题,采用片、丝相结合的分步分比例加料技术,即在白肋烟叶片经回潮、增温松散后进行片加料,切丝后进行丝加料,并对最佳料液施加分配比例进行了研究。结果表明:采用分步分比例加料技术,当片加料料液分配比例为75%,丝加料料液分配比例为25%时,加料均匀系数由采用传统叶片两次加料技术时的53.52%提高到90.14%,料液有效利用率由61.19%提高到88.25%。     

双面喷射式加料机控制参数对片烟加料效果的影响

为完善双面喷射式加料工艺技术,探索影响双面喷射式加料效果的因素,采用单因素试验和正交试验的方法分析了双面喷射式加料机控制参数对片烟加料效果的影响。结果表明:1在试验范围内,随着HT蒸汽压力的增加,加料均匀系数呈降低趋势,有效利用率呈先升高后降低趋势;随着摊薄皮带电机频率、料液引射压力、出料网带电机频率、排潮风机频率的增加,加料均匀系数及有效利用率均呈先升高后降低趋势。2较适宜的加料参数组合为:HT蒸汽压力0.1 MPa、摊薄皮带电机频率32 Hz、料液引射压力0.20 MPa、出料网带电机频率43 Hz、排潮风机频率30 Hz。3与传统的滚筒式加料相比,双面喷射式加料的加料均匀系数提高了约1.83%,料液有效利用率提高了13.57百分点。     

不同引射介质烟片加料效果的比较

分别采用压缩空气和蒸汽作为引射介质加料,对比了两种引射介质加料后烟片温度及其稳定性、烟片含水率及其均匀性及加料均匀性和料液有效利用率.结果表明:蒸汽引射加料后烟片含水率、烟片料液含量更加均匀,烟片温度、含水率较高,两种引射介质加料后烟片温度稳定性、料液有效利用率无明显差异.     

滚筒加料机内物料流动特性及正交试验研究

针对滚筒加料机内物料混料不均匀和损耗等问题,以加料机转速、烟叶容积率及烟叶颗粒粒径为影响物料混料流动特性的主要因素,以物料在混料过程中的空压气速度分布、烟叶浓度分布、料液运动轨迹分布及香料液浓度分布为评价指标,在正交试验设计的基础上运用FLUENT数值模拟技术模拟滚筒加料机内的物料流动混合特性。结果表明,各因素对加料质量的影响顺序：烟叶颗粒粒径>加料机转速>烟叶容积率,并在此基础上确定各影响因素的最优组合,即加料机转速9 rad/min、烟叶容积率35%、烟叶颗粒粒径10 mm。通过加料工艺生产试验线,对加料效果优化最优参数进行验证,试验结果与数值计算方法的计算结果吻合良好。研究结果为加料机内物料流动特性分析、烟叶加料装置以及加料工艺技术参数的优化提供一定的理论参考。     

润叶加料供水流量稳定性研究

卷烟厂在制丝工艺中,润叶加料是十分重要的一道工序。该工序点的水分控制如何,直接影响到成品烟丝的吸味及内在质量指标。在含水率控制过程中,仅凭操作人员的经验设定喷水量对物料进行加水,经常出现出口水分波动较大,影响了烟叶的含水率,进而影响到成品烟丝的品质。为了给润叶加料筒的水分控制提供一个更好的方案,在结合技术改造的实际情况以及相关控制技术理论研究的基础上,在改造过程中提出采用增加稳压稳流系统控制方式,结合对润叶加料工序的含水率控制,较好地解决出口片烟含水率波动大的问题。实际运用效果表明,这是一种有效控制方案,改进后该工序含水率控制合格率大幅度提高,保证了成品烟丝质量。     

微波法干燥叶丝研究

为使叶丝达到较好的物理、化学和感官质量指标,采用微波加热和真空脱水相结合的新型工艺干燥叶丝,通过对有关工艺参数进行的研究和优化,确定出微波干燥的最佳工艺参数:HT蒸气压力0.8MPa,叶丝含水率24%,微波辐射时间8min,脱水真空压力-0.054MPa。同时,采用常规物理、化学分析和评吸方法对微波与烘丝机干燥的叶丝质量进行了对比。结果表明,微波干燥可以使叶丝的填充能力提高12%左右;水溶性总糖和还原糖比烘丝机干燥叶丝的分别高1.7%和1.6%,而总植物碱和总氮含量则分别低0.14%和0.35%,其它化学成分无明显差异;卷烟质量得到明显提高,单支重量、烟气烟碱量和焦油量各下降13 4%、21 2%和4%。     

润叶加料工序含水率控制及相关算法研究

制丝生产线润叶加料工序在含水率控制过程中,采用传统的单闭环控制方式,仅凭操作人员的经验设定喷水量对物料进行加水,导致出口片烟含水率波动较大、控制失调,影响成品烟丝的内在质量.为此,采用带前馈-串级双闭环控制方式,对润叶加料工序的含水率控制及其控制算法进行了优化改进.该控制方式将来料含水率波动、加料比例、直喷蒸汽和温度等影响因素进行了精确的量化处理,并对其控制算法进行了改进完善,较好地解决了出口片烟含水率波动大的问题.实际运行效果表明,带前馈-串级控制系统是制丝生产过程中改善和提高片烟加工含水率稳定性的一种有效控制方案,改进后该工序点含水率控制合格率由原来的80％提高到99.8％以上,保证了成品烟丝质量.     

影响卷烟端部落丝量的因素研究

通过卷制结构不同的烟丝、测试通过卷接设备的烟丝结构、调整设备参数及喂丝方式等实验，发现烟丝的结构和耐加工性能是影响卷烟端部落丝量的主要因素，卷接设备的参数调整、喂丝方式是影响卷烟端部落丝量的次要因素。     

不同磷钾处理下套作大豆干物质积累及钾肥利用率的动态变化

在磷钾供应条件下,以贡选1号为材料,研究了田间套作大豆干物质积累及钾肥利用率的动态变化。结果表明,套作大豆干物质积累量和钾素吸收量均随生育时期推进而持续增加,均符合＂S＂形曲线,可用Logistic方程y=k/（1＋ae-bx）拟合。干物质积累速率前期缓慢,随后迅速上升,出苗后79.3d达到高峰后缓慢下降,钾肥吸收速率与干物质积累速率趋势一致,但最大吸收速率出现时间（出苗后73.6d）早于干物质积累最大速率出现时间。钾肥利用率呈现先升高后降低的趋势,最高阶段利用率与最大吸收速率出现时间基本一致（出苗后75d～90d）。施用磷钾提高了钾素吸收速率、干物质积累速率、钾肥积累利用率和阶段利用率,但没有改变其变化趋势。     

基于X光检测的烟丝异物在线剔除系统

利用不同密度物质吸收X光能力的差异,设计了基于X光检测的烟丝异物在线剔除系统。该系统利用X光透射烟丝后,形成原始密度值数据,利用原始密度值的突变进行烟丝异物判别,实现烟丝异物在线检测识别的功能。该系统设计了独特的平行四边形喷吹异物剔除方式,使得异物处于接近平行四边形中心点的位置,提高了异物剔除的有效性。经实验验证,将设备安装于制丝线贮丝柜出口处,能有效实现对各类金属、非金属异物识别和剔除,其对烟丝异物平均识别率达99.5%以上,平均剔除率达95.8%以上。     

Evaluation of innovative immersion vacuum cooling with different pressure reduction rates and agitation for cooked sausages stuffed in natural or artificial casing

Effects of different pressure reduction rates and liquid agitation (523 rpm) on sausage successful rate, cooling time, cooling loss, texture properties, chemical and physical parameters were analysed by ANCOVA. Tested linear pressure drop rate from 320 mbar to 50 mbar was 20 (L 20), 30 (L 30), or 40 (L 40) mbar/min for artificial casing sausages (ACS) and 60 (L 60), 80 (L 80), or 100 (L 100) mbar/min for natural casing sausages (NCS). From 50 mbar until 6.4 mbar, 5 mbar/min was used for both casings. NCS were more suitable than ACS for IVC. The recommended pressure reduction rate was 30 mbar/min for ACS and 60 mbar/min for NCS. ACS under 30 mbar/min with agitation (LA 30) presented significantly higher texture property values than that without agitation (L 30) (P < 0.05). Cooling time (to 4 °C) of NCS under 60 mbar/min and agitation (LA 60) was significantly shorter than that without agitation (L 60) (P < 0.05). This study could assist meat processors or manufactures when choosing a suitable pressure drop rate for different types of sausages.     

Factors influencing variation of fatty acid content in ovine milk

Between January 2006 and December 2007, a total of 4,579 test-day observations for contents of milk fatty acids (FA) were obtained from 2,218 lactations of 1,109 ewes belonging to 14 Churra dairy flocks. The 36 analyzed FA were quantified as grams per 100 g of total FA and were grouped as 18 dependent variables: 10 FA, 6 groups of FA, and 2 FA indexes. Flock, day of testing within flock (TD), ewe age, stage of lactation, and season effects contributed significantly to variations in FA. The 2 most important variation factors were flock (3 to 30% of total variance) and TD (35 to 70% of total variance). The percentage of variance explained by the TD effect for conjugated linoleic acid (CLA, C18:2 cis-9, trans-11) and linolenic acid (C18:3 cis-9, cis-12, cis-15) was particularly high: 60.7 and 68.2%, respectively. The season effect was also a very important variation factor, closely linked to feeding. The most significant seasonal variations were observed in polyunsaturated FA, with the highest values occurring in spring and summer and the lowest in winter. More specifically, CLA and linolenic acid contents were 44 and 30% higher in spring-summer than in winter. As the age of the ewe increased, the monounsaturated and polyunsaturated FA decreased and the short- and medium-chain saturated FA increased. The CLA and the CLA/C18:1 trans-11 Δ⁹-desaturase index increased significantly throughout lactation. The correlation coefficient between rumenic acid (CLA) and vaccenic acid was high (0.47) because of the precursor-product relationship via the Δ⁹-desaturase enzyme. The correlation coefficients were high between C10:0 and C12:0 (0.79), C12:0 and C14:0 (0.73), and C14:0 and C16:0 (0.29), probably because of their similar metabolic origin. Positive correlations were also obtained among the C₁₈ FA family. All the studied factors of FA variation would be considered as fixed effects in the statistical models used for estimation of genetic and phenotypic parameters from test-day records of commercial flocks.     

复合抗氧化剂对油炸鲜切薯片中丙烯酰胺和氯丙醇酯的抑制作用

目的 研究由植酸和鼠尾草酸组成的复合抗氧化剂对油炸鲜切薯片中丙烯酰胺和氯丙醇酯的抑制作用。方法 通过测定酸价(acid value, AV)和过氧化值(peroxide value, POV)对不同浓度植酸和鼠尾草酸进行评估, 并利用响应面优化实验确定复合抗氧化剂的最优配比。同时以油炸鲜切薯片为研究对象, 评价复合抗氧化剂对薯片和油脂中丙烯酰胺、氯丙醇酯及其品质的影响。结果 在180℃ 30 min下, 植酸抗氧化最佳浓度为0.16 g/kg, 鼠尾草酸最佳浓度是0.4 g/kg。根据响应面优化法设计实验并通过数据方差分析和响应面图可得: 在植酸浓度0.06 g/kg, 鼠尾草酸浓度0.2 g/kg时, AV和POV达到最低, 油脂抗氧化效果最好。复合抗氧化剂对丙烯酰胺的抑制率最高可达80.5%, 对氯丙醇酯有一定的抑制作用, 其中对3-氯-1,2-丙二醇酯抑制率最高达到49.2%。结论 复合抗氧化剂在提高棕榈油煎炸稳定性、抑制丙烯酰胺和氯丙醇酯产生方面表现出较好的优势, 能有效延缓煎炸油品质恶化, 并且对煎炸油和薯片品质有一定的保护作用。     

施肥方式对玉米-大豆套作体系氮素吸收利用效率的影响

通过田间试验探讨了Al（N,210kg·hm^-2）、A2（N,270kg·hm^-2）、A3（N,330kg·hm^-2）3种施氮水平和距窄行玉米B1（0cm）、B2（15cm）、B3（30cm）、B4（45cm）4种施肥距离对玉米一大豆套作体系氮素吸收利用效率的影响。结果表明,与习惯施氮（A3）相比,减量施氮（A1、A2）提高了大豆R2、R5期单株根瘤数、根瘤干重和根瘤固氮潜力,以距玉米15cm处施肥的根瘤固氮能力较强;玉米、大豆的籽粒产量、地下部植株氮素吸收量和氮肥利用率随施氮量的增加呈先增加再降低的趋势,以A2处理的最高;施肥距离过大和过小均不利玉米、大豆产量的提高和氮素的吸收利用,以距玉米15～30cm处施肥效果最佳;减量施氮18％（A2）时,B2、B3处理相对常规穴施（B1）处理,玉米、大百及玉米一大豆系统的籽粒产量、植株氮素吸收量、氮肥利用率和土壤总氮含量均显著提高,土壤氮素贡献率显著降低。     

基于图像模拟和支持向量机的复合非织造布孔隙尺寸预测

为探究非织造布复合前后孔隙尺寸的变化规律,以纤维根数、纤维平均直径、纤维直径变异系数为变量生成数字图像(复合单元)对非织造纤维网进行模拟,并采用将2个复合单元叠加的手法来模拟复合后的非织造纤维网。用2个复合单元的孔径差异百分比(E_r)和孔径变异系数的平均值(M_V)表征复合前孔隙尺寸;孔径复合指数(I_P) 和孔径变异系数复合指数(I_V)用于表征复合后孔隙尺寸。结果显示非织造布复合前后的孔隙尺寸呈复杂的非线性关系。将E_r和M_V作为支持向量机模型的输入分别对I_P和I_V进行预测,其绝对百分比误差分别为1.84%和1.92%,误差很小。验证实验的结果进一步印证支持向量机模型具有很高的预测准确度。     

Dependence of the effective diffusion coefficient of moisture with thickness and temperature in convective drying of sliced materials. A study on slices of banana, cassava and pumpkin

Several studies have indicated that effective diffusion coefficients of slices apparently vary with the thickness of the samples. Even though the effective diffusion coefficients have been observed to be dependent on the square of the slice thickness, a theoretical explanation to this behavior is not available to date. A theoretical model is formulated herein, in order to correlate effective diffusion coefficient of moisture in the slices with the slice thickness. Experiments are carried out for drying of slices of different thicknesses of banana, cassava and pumpkin in order to evaluate the effective diffusion coefficients. The model is found to describe the variation of the effective diffusion coefficient with slice thickness very satisfactorily. A possibility of the estimation of the axial and radial diffusion coefficients of moisture in the slices is also outlined.     

The effects of forage proportion and rapidly degradable dry matter from concentrate on ruminal digestion in dairy cows fed corn silage-based diets with fixed neutral detergent fiber and starch contents

This study investigated the effects of the forage-to-concentrate (F:C) ratio and the rate of ruminal degradation of carbohydrates from the concentrate on digestion in dairy cows fed corn silage-based diets. Six cows with ruminal cannulas were assigned to 6 treatments in a 6 × 6 Latin square. Treatments were arranged in a 3 × 2 factorial design. Three proportions of neutral detergent fiber from forage [FNDF; 7.6, 13.2, and 18.9% of dry matter (DM)] were obtained by modifying F:C (20:80, 35:65, and 50:50). These F:C were combined with concentrates with either high or low content of rapidly degradable carbohydrates. The dietary content of rapidly degradable carbohydrates from the concentrate was estimated from the DM disappearance of concentrate after 4 h of in sacco incubation (CRDM). Thus, 2 proportions of CRDM were tested (20 and 30% of DM). Wheat and corn grain were used as rapidly and slowly degradable starch sources, respectively. Soybean hulls and citrus pulp were used as slowly and rapidly degradable fiber sources, respectively. Concentrate composition was adjusted to maintain dietary starch and neutral detergent fiber contents at 35.9 and 28.9% of DM, respectively. There was no effect of the interaction between F:C and CRDM on DM intake (DMI), ruminal fermentation, chewing activity, and fibrolytic activity. When F:C decreased, DMI increased, the mean ruminal pH linearly decreased, and the pH range linearly increased from 0.95 to 1.27 pH unit. At the same time, the acetate-to-propionate ratio decreased linearly. Decreasing F:C linearly decreased the average time spent chewing per kilogram of DMI from 35.2 to 19.5 min/kg of DMI and decreased ruminal liquid outflow from 11.6 to 9.2 L/kg of DMI, suggesting a decrease in the salivary flow. Increasing CRDM decreased DMI and increased the time during which pH was below 6.0 (3.1 vs. 4.8 h), the pH range (0.90 vs. 1.33), and the initial rate of pH drop. It also increased the volatile fatty acid range (35 vs. 59 mM), thus suggesting an increased rate of fermentation. It also decreased the acetate-to-propionate ratio (2.9 vs. 1.8). Increasing CRDM barely affected the average time spent chewing per kilogram of DMI and the ruminal liquid outflow. These results suggest that rumen pH is controlled by different mechanisms when F:C is decreased or when CRDM is increased. Consequently, FNDF is a good predictor of the chewing time, whereas CRDM is a good predictor of the pH range and volatile fatty acid profiles. Finally, considering both FNDF and CRDM improves the prediction of mean pH.