卷烟燃烧锥温度分布的表征方法

为了更加准确地表征卷烟燃烧锥内部的温度分布情况,提出了以温度为基准确定抽吸时刻的检测方法,考察了连线法、最近邻点法、改进谢别德法、克里格插值法、双三次插值法和径向基函数法6种插值方法对温度分布的影响,并利用确定的插值方法,对燃烧锥的温度分布进行了数字化分析.结果表明:①以温度为基准确定抽吸时刻解决了燃烧线法灵敏度较低的问题,保证了进行插值计算时温度数据的准确性;②克里格插值法所得温度分布曲线平滑,插值精度较高,考察样本的平均相对误差为9.86％,解决了传统连线法存在的温度分布可读性较差及插值准确度较低的问题.     

烟丝含水率对细支卷烟的影响

考察了烟丝含水率对细支卷烟烟支物理性能、烟支内部烟丝结构分布、烟支静燃速率、抽吸时燃烧锥落头率、卷烟主流烟气释放和感官质量的影响。结果表明,细支卷烟烟丝含水率为11.5%~13.8%,在卷烟单重一致的情况下,烟丝结构分布、卷烟抽吸时燃烧锥落头率以及感官抽吸品质受烟丝含水率影响大。烟丝含水率增大,烟丝抗造碎性能增强,烟支中大尺寸烟丝所占比例增加,烟末减少,卷烟抽吸时燃烧锥落头现象明显减轻;烟丝含水率从11.5%增加到12.9%,燃烧锥落头率可从65%降低至30%。烟丝含水率过高会导致卷烟烟气浓度减小,满足感降低。此外,烟丝含水率增大,细支卷烟的烟支硬度、烟支静燃速率、烟气焦油和烟碱释放量也会发生细微的变化。综上,建议细支卷烟生产过程中烟丝含水率尽量控制在12.5%~12.9%。     

卷烟纸罗纹对卷烟燃烧温度和烟气常规成分的影响

为探讨卷烟纸罗纹参数变化对卷烟燃烧温度和烟气常规成分的影响,对不同参数卷烟进行卷烟燃烧锥温度和主流烟气常规成分的测定。结果发现:卷烟纸罗纹形式、罗纹强度和压纹方式对卷烟燃烧温度和卷烟常规烟气成分有不同程度影响;采用无罗纹卷烟纸、浅罗纹卷烟纸、正压卷烟纸的卷烟,其燃烧最高温、抽吸最高温平均温度、抽吸平均温度、阴燃平均温度、峰值平均值较高,烟气CO释放量较低;烟气中焦油、CO与抽吸燃烧锥最高温平均值呈现显著负相关关系。卷烟纸罗纹参数优化设计可改变卷烟燃烧温度,降低主流烟气焦油和CO释放量。      

ISO和HCI抽吸模式下卷烟燃烧状态与主流烟气成分对比分析

为了解卷烟在不同抽吸模式下的燃烧状态与烟气释放情况,采用微细热电偶法测量了卷烟在ISO标准抽吸模式和加拿大深度抽吸模式(HCI)下连续抽吸两口的温度分布数据,以表征卷烟的燃烧状态,同时分析了主流烟气中焦油、烟碱等化学成分的释放量。结果表明:(1)HCI抽吸模式下,卷烟的燃烧锥体积(V0)、最高温度(Tmax)、特征温度(T0.5)、温度范围(T0.1～T0.9)及燃烧速率相对较大;两种抽吸模式下,抽吸第二口时燃烧锥的体积和最高温度均高于第一口,高温区域所占比例则低于第一口。(2)两种抽吸模式下,燃烧锥内部区域温度均先增大后减小,表面温度则先减小后增大;HCI抽吸模式下,卷烟燃烧锥内部温度和升温速率整体高于ISO模式,表面温度则低于ISO模式。(3)HCI抽吸模式下,卷烟主流烟气的化学成分释放量高于ISO模式,单位质量烟丝释放量是ISO模式下的1.396～3.041倍(邻甲酚除外)。该研究结果可为了解卷烟燃烧过程和机制、优化卷烟设计提供参考。     

3种圆周卷烟逐口抽吸燃烧状态的变化规律

为了研究3种圆周卷烟在逐口抽吸过程中燃烧状态的变化情况,设计3种圆周卷烟（17、20、24 mm）,测量卷烟逐口抽吸过程中温度特征参数（燃烧锥体积V0、最高温度Tmax、特征温度T0.5、体积平均温度Tm）的变化,探讨卷烟燃烧锥燃烧状态之间的差异性。实验结果表明：(1)随着卷烟圆周的增加,卷烟燃烧锥体积增加,高温区域所占比例有所降低,而最高温Tmax和体积平均温度Tm差异较小。(2)17和20 mm卷烟在逐口抽吸过程中,燃烧锥体积V0无显著变化,而24 mm卷烟的燃烧锥体积V0在第3口时达到最大,最高温度Tmax没有显著变化;(3)20和24 mm圆周卷烟在逐口抽吸过程中,特征温度T0.5和体积平均温度Tm整体呈下降趋势,而17 mm圆周卷烟在第4口左右有一个明显上升趋势;(4)卷烟温度特征参数的变化率在卷烟的整个抽吸过程中具有较好的一致性,表明造成卷烟逐口抽吸温度特征参数差异的原因主要是抽吸前卷烟燃烧状态的不同。     

卷烟纸对卷烟燃烧性能的影响

卷烟纸作为卷烟的主要辅料,由于它直接参与燃烧,所以对卷烟的燃烧性能有着直接的影响.本文所探讨的卷烟燃烧性能,从以下两方面来进行认识和分析:一是卷烟燃烧后从外观视觉效果所体现的外观燃烧性能,如燃烧速度、静燃时的侧流烟气、包灰的牢固性、灰色、燃烧碳化圈、卷烟燃烧锥等.二是卷烟燃烧的内在性能,即烟支燃烧后的烟气组分,其中主要是CO、焦油和烟碱的含量.通过调整卷烟纸的生产工艺,可对上述两方面卷烟燃烧性能进行适当的调节.     

金属盐对卷烟纸裂解致孔及主流烟气中CO释放量的影响

为考察柠檬酸钾、醋酸钙、醋酸锌、氯化钙、氯化锌等不同金属盐对卷烟纸裂解行为及卷烟主流烟气中CO释放量的影响,采用热分析法研究卷烟纸的热裂解行为,采用压汞法和扫描电镜(SEM)法表征了卷烟纸微孔结构,并通过测试卷烟燃烧锥温度分布研究了金属盐对卷烟燃烧温度分布的影响。结果表明:1添加不同金属盐的卷烟纸对卷烟烟气CO释放量有不同的影响,柠檬酸钾促进了卷烟纸纤维的裂解致孔作用,使炭化线附近卷烟纸的孔容和微孔数目增多,扩散和稀释共同作用使主流烟气CO释放量显著降低;而醋酸锌、醋酸钙、氯化钙和氯化锌可抑制卷烟纸纤维的裂解致孔作用,使炭化线附近卷烟纸的孔容和微孔数目减少,主流烟气CO释放量显著增加。2与空白对照样相比,添加柠檬酸钾的卷烟纸,其卷烟在高温区域(750℃以上)燃烧锥的体积减小;而添加醋酸锌、醋酸钙、氯化钙和氯化锌的卷烟纸,其卷烟的高温燃烧锥体积增加。因此,卷烟纸中金属盐的添加对卷烟燃烧锥的体积和CO释放量具有显著的影响,卷烟高温区域燃烧锥的体积越小,其主流烟气中CO的释放量越低。     

卷烟燃烧锥形态参数测定及与燃烧速度间的关系

为深入了解卷烟的燃烧性能,建立了一种基于图像处理技术的卷烟燃烧锥长度、面积、偏离角等形态参数的测定方法,通过48种卷烟样品自由燃烧速度及燃烧锥形态参数的测定,研究了卷烟燃烧锥形态参数与自由燃烧速度间的关系。研究结果表明:（1）48种卷烟燃烧锥锥长、锥面积、偏离角的RSD分别介于2.7%~10.1%、1.1%~10.1%、12.0%~78.3%之间,其中燃烧锥长度及面积的重复性较好,依据测量结果区分样品间差异性的灵敏度较高。（2）48种卷烟的燃烧锥锥长、锥面积和偏离角分别介于6.604~14.017mm、38.729~92.825mm2、2.778~7.636°之间,不同牌号卷烟的三项燃烧锥形态参数均存在极显著差异性。（3）卷烟自由燃烧速度与燃烧锥锥长和面积间均存在极显著正相关关系,且两者之间存在交互作用。      

卷烟燃烧参数、灰分外观和烟气成分相互关系研究

  目的  揭示卷烟燃烧三个维度之间相互关系。  方法  利用统计分析方法研究了卷烟燃烧参数（燃烧温度、耗氧量和燃烧速率）、灰分外观指标（灰色值、裂口率、缩灰率、炭线宽度、炭线整齐度和持灰力）和烟气成分（烟气常规成分和七种有害成分）之间的相关性。  结果  ① 烟丝静燃速率、卷烟吸燃速率和耗氧量之间呈极显著正相关,但均与燃烧温度和卷烟纸阴燃速率无显著相关性;卷烟静燃速率仅与耗氧量显著正相关,燃烧温度仅与卷烟纸阴燃速率呈极显著负相关。②燃烧速率参数不仅与多种烟气成分显著负相关,亦与灰分外观质量显著正相关,与燃烧温度和耗氧量相比,是调节卷烟烟气和灰分外观质量更为有效的燃烧参数。      

2000年CORESTA会议论文摘要

1　卷烟阴燃机理研究了卷烟阴燃机理。为了表示卷烟阴燃蔓延的特征 ,分析了用ＣＣＤ摄像机摄制的阴燃卷烟的影象。在稳定态并不发生卷烟阴燃 ,当盘纸断续燃烧时才观察到静态卷烟阴燃的蔓延。我们发现 ,卷烟的阴燃速率取决于卷烟边缘盘纸的燃烧速率 ,且随点燃卷烟边缘所需的时间差别而变化。为了测定阴燃卷烟中某个理想点的温度随时间的变化 ,用一台热敏成像仪摄取了一支阴燃卷烟的热影象。还观察了卷烟边缘的断续燃烧。在卷烟阴燃蔓延线处的温度并没有单调地上升。我们建立了一个卷烟阴燃模型 ,并阐明卷烟边缘的导热率是影响卷烟静燃速率的…     

Control of electrothermal heating during regeneration of activated carbon fiber cloth

Electrothermal swing adsorption (ESA) of organic gases generated by industrial processes can reduce atmospheric emissions and allow for reuse of recovered product. Desorption energy efficiency can be improved through control of adsorbent heating, allowing for cost-effective separation and concentration of these gases for reuse. ESA experiments with an air stream containing 2000 ppm(v) isobutane and activated carbon fiber cloth (ACFC) were performed to evaluate regeneration energy consumption. Control logic based on temperature feedback achieved select temperature and power profiles during regeneration cycles while maintaining the ACFC's mean regeneration temperature (200 °C). Energy requirements for regeneration were independent of differences in temperature/power oscillations (1186-1237 kJ/mol of isobutane). ACFC was also heated to a ramped set-point, and the average absolute error between the actual and set-point temperatures was small (0.73%), demonstrating stable control as set-point temperatures vary, which is necessary for practical applications (e.g., higher temperatures for higher boiling point gases). Additional logic that increased the maximum power application at lower ACFC temperatures resulted in a 36% decrease in energy consumption. Implementing such control logic improves energy efficiency for separating and concentrating organic gases for post-desorption liquefaction of the organic gas for reuse.     

气垫式热风箱及纸张传热性能模拟研究

通过最小二乘法研究热空气在气垫式热风箱内的速度、静压、温度分布,探讨了入口风速、高度比、入口温度、开孔率和喷口方式对气垫层不均匀指数、气垫静压和表面传热系数的影响规律。通过量纲分析拟合Nu的函数关系式,数值模拟值与拟合值比较表明,最大相对误差为9.53%,均方根误差为9.5%,拟合方程可为热风箱气垫层表面传热系数的优化研究提供参考。     

Short communication: A new mathematical model for thin layer drying of fruits

The aim of this study was to fit a new mathematical model on the thin layer drying curves of fruits. Thin layer drying studies at different temperatures (60, 80 and 100 °C) were carried out on two varieties each of kiwifruit and apricot. The new model was compared statistically with three other drying models (Henderson and Pabis, Page and logarithmic) published in the literature. The proposed equation gave the highest coefficient of determination for both varieties of kiwifruit and apricot and closely followed by the Page equation. Statistical evaluation of the experimental and predicted moisture ratio showed that the proposed equation consistently gave the lowest reduced Chi‐square, root mean square error and mean relative percentage error. The results indicate that the proposed equation has the best curve fitting ability for both fruits. However, there is no theoretical basis offered for the good curve fitting ability of the equation.     

人工神经网络和响应面法优化薏苡仁酒发酵条件

采用Box-Behnken试验设计对薏苡仁酒的发酵条件进行优化，并对Box-Behnken（BB）试验结果分别进行响应面法（RSM）和人工神经网络（ANN）分析。结果表明，RSM、ANN优化发酵条件分别为薏苡仁∶糯米为1∶2（g∶g）、酵母A1接种量为4.7%、温度为31.7 ℃、初始pH为3.0；薏苡仁∶糯米为1∶1.9（g∶g）、酵母A1接种量为4.2%、温度为28.1 ℃、初始pH为3.0，ANN、RSM分别在其最优条件下的实际值和预测值都基本一致。ANN、RSM拟合模型的相关系数（R）、决定系数（R2）、均方误差（MSE）、均方根误差（RMSE）、平均绝对误差（MAE）、平均绝对百分比误差（MAPE）分别为0.994 5、0.988 9、0.011 7、0.108 4、0.072 2、0.486 3%和0.983 6、0.967 5、0.028 9、0.170 1、0.143 7、0.985 7%。ANN具有更高拟合能力和准确性，拟合效果更好，更适合应用于薏苡仁酒发酵条件优化。     

基于挥发性盐基氮快速预测冷鲜鸡货架期

为了解冷鲜鸡的货架期,以挥发性盐基氮（TVB-N）为品质表征参数,研究了冷鲜鸡在不同温度（5、10和15 ℃）下的变化规律,利用Arrhenius方程建立了不同温度下冷鲜鸡货架期预测模型,并对该模型进行内部验证和实际样本验证。结果表明:Arrhenius方程中TVB-N的活化能Ea为52.636 kJ/mol,指前因子k₀为3.8×107。以5、10和15 ℃作为验证温度,其相对误差为6.30%,6.00%和3.91%,实际样本验证最大相对误差为?10.5%,说明该模型拟合效果好。通过该模型可快速获得不同贮藏温度下冷鲜鸡的货架期,为生产企业和监管部门制定货架期标准提供理论依据。     

不同产地烤烟烟叶自由燃烧速度研究

为了解各种单料烟的燃烧性能 ,为低焦油卷烟叶组配方设计中合理选用烟叶提供参考依据 ,对国内一些主要产区的烤烟以及津巴布韦烤烟的自由燃烧速度进行了测试和对比分析。结果表明 ,不同产地烟叶的自由燃烧速度有很大的差别。从产地看 ,在相同等级中 ,以贵州B2F、湖南永兴C2F、黑龙江勃利C2L、四川黔阳X2F和B2L、贵州道真X2L的燃烧性能为好。从总体看 ,燃烧性能最好的为贵州道真X2L( 5 .645mm min) ,最差的为河南正阳B2F( 2 .95mm min)。津巴布韦烟叶的燃烧性能中等 ,其中以B2O燃烧性能较好     

不同温度条件下养殖大菱鲆菌群变化和货架期预测

对低温(0~10℃)、室温(25℃)和变温贮藏条件下养殖大菱鲆的细菌种群变化进行研究,确定不同温度条件下养殖大菱鲆的优势腐败菌和货架期,并采用Exponential、School-field和Square-root方程构建货架期预测模型,并对货架期预测模型的适用性进行评价和验证。结果显示,低温贮藏大菱鲆货架期为6.1~32.6 d,优势腐败菌为腐败希瓦氏菌(40.3%)和假单胞菌属(27.4%),室温时货架期为1.3 d,优势腐败菌为气单胞菌(47.1%)和腐败希瓦氏菌(29.4%);构建的Exponential、School-field和Square-root货架期模型参数分别为温度特征系数a=0.12,T_(min)=-6.6℃,表观活化能(E_a)为81.4 k J/mol,采用均方根误差、残差平方和、偏差度、准确度对模型的拟合优度进行比较,Square-root模型预测性能最优,用恒温和变温对3种货架期预测模型进行验证,显示Square-root货架期模型误差最小,可有效预测恒温和变温条件下大菱鲆的货架期。     

Equilibrium moisture content of bell pepper

Equilibrium moisture content (EMC) of bell pepper at selected levels of temperature (30‐70°C) and relative humidity (10‐75%) of the surrounding air was determined experimentally by the static method. The EMC increased with relative humidity but decreased with increase in temperature. Results demonstrated that Henderson model predicted accurately the variation of EMC with relative humidity at selected temperatures. The standard error was less than 0.077 while correlation coefficient was greater than 0.942 in all cases.     

A study on the kinetic behavior of Listeria monocytogenes in ice cream stored under static and dynamic chilling and freezing conditions

The kinetic behavior of Listeria monocytogenes in 2 commercial ice cream products (A and B) that were inoculated and stored under static chilling (4 to 16°C), static freezing (−5 to −33°C), dynamic chilling, and dynamic chilling-freezing conditions was studied, simulating conditions of the aging process and of normal or abuse conditions during distribution and storage. The ice cream products A and B had different compositions but similar pH (6.50 and 6.67, respectively) and water activity (0.957 and 0.965, respectively) values. For both chilling and freezing conditions, the kinetic behavior of the pathogen was similar in the 2 products, indicating that the pH and water activity, together with temperature, were the main factors controlling growth. Under chilling conditions, L. monocytogenes grew well at all temperatures tested. Under freezing conditions, no significant changes in the population of the pathogen were observed throughout a 90-d storage period for either of the inoculum levels tested (10³ and 10⁶ cfu/g). Growth data from chilled storage conditions were fitted to a mathematical model, and the calculated maximum specific growth rate was modeled as a function of temperature by using a square root model. The model was further validated under dynamic chilling and dynamic chilling-freezing conditions by using 4 different storage temperature scenarios. Under dynamic chilling conditions, the model accurately predicted the growth of the pathogen in both products, with 99.5% of the predictions lying within the ± 20% relative error zone. The results from the chilling-freezing storage experiments showed that the pathogen was able to initiate growth within a very short time after a temperature upshift from freezing to chilling temperatures. This indicates that the freezing conditions did not cause a severe stress in L. monocytogenes cells capable of leading to a significant “additional” lag phase during the subsequent growth of the pathogen at chilling conditions. As a result, the application of the model at chilling-freezing conditions resulted in satisfactory performance, with 98.3% of the predictions lying within the ± 20% relative error zone. The present study provides useful data for understanding the behavior of L. monocytogenes in ice cream stored under single or combined chilling and freezing conditions. In addition, the study showed that such data can be expressed in quantitative terms via the application of mathematical models, which can be used by the dairy industry as effective tools for predicting the behavior of the pathogen during the manufacture, distribution, and storage of ice cream products.     

基于入口介质温湿度控制的新型松散回潮控制模式性能评价

对以入口介质温湿度作为控制参数的新型松散回潮控制模式,分别采用阶跃响应曲线法和梯度调节的方法,分析评价了其动态特性和稳态特性,并进一步验证了其实际应用性能。结果表明,采用以入口湿空气温湿度为主要控制因素的控制方法,控制响应迅速,控制方式对入口介质温湿度的调节性能好。与控制回风温度的控制方式相比,该控制方法可显著提高片烟加工质量的稳定性,片烟出口温度偏差由0.87℃降低至0.55℃,出口含水率偏差由0.54%降低至0.47%。