Comparison of Benefits of Different Tobacco Loading Methods and Matching Baking Processes in Intensive Curing Houses

[Objectives]To compare the benefits of different tobacco loading methods and supporting baking processes in intensive curing houses.[Methods]Flue-cured tobacco variety K326 was taken as material,and comparative experiment on baking effects of six tobacco loading methods(traditional hanging pole,loose leaf stacking,loose leaf binding and inserting,loose leaf inserting,loose leaf net basket,loose leaf grid)was conducted.[Results]Cost of dry tobacco loading equipment for hanging pole and loose leaf stacking was 0.01 and 0.1 yuan/kg,and cost of tobacco loading by loose leaf basket reached 0.36 yuan/kg.Labor cost for baking dry tobacco by direct stacking of loose leaves reached 2.02 yuan/kg,which was the lowest,while labor cost for binding and inserting loose leaves reached 2.44 yuan/kg,which was the highest.Energy consumption cost of dry tobacco baking with loose leaf grid was 1.06 yuan/kg,which was the lowest,while baking energy consumption cost of loose leaf stacking reached 1.23 yuan/kg,which was the highest.From the perspective of baking income,loose leaf inserting reached 21.36 yuan/kg,which was the lowest,while net basket reached 27.79 yuan/kg,which was the highest,followed by grid(23.46 yuan/kg)and loose leaf binding and inserting(22.5 yuan/kg).[Conclusions]It is worth popularizing the loose leaf binding and inserting and the loose leaf grid baking.

Dynamic regimes of cemented backfill at early-age

In view of the mechanics characteristic of cemented tailings backfill(CTB)at early age,the separation Hopkinson pressure bar test device was used to explore the effects of curing age and impact energy.A total of 48 CTB samples with diameter of 50 mm and length of 25 mm were prepared with curing ages of 3,5,7 and 9 d.Impact tests under different impact energy(10,20,30 and 40 J)were carried out.The microstructure of CTB at different ages was analyzed by scanning electron microscopy(SEM).The results show that,the curing age mainly affects the mechanical properties and internal structure of early-age CTB.With increasing curing age,the mechanical properties of early-age CTB change from viscoelasticity to brittleness.The impact energy mainly affects the response of dynamic peak compressive strength to strain rate.Under low strain rate,the structure of CTB is broken,but still has bearing capacity,affecting the formation of later strength.It is concluded that the structural loses completely under the action of high strain rate.Therefore,the control of impact energy and the protection of curing age should be fully considered in actual production process.

Effects of curing under step-by-step load on mechanical and deformation properties of cemented gangue backfill column

A step-by-step load was utilized to mimic the load history of the backfill column in the in-situ curing process.The inner damage of the specimen during curing and uniaxial compressive testing was monitored by electrical resistivity and ultrasonic equipment.Results show that:1)Uniaxial compressive strength(UCS)and elastic modulus(EM)of the samples curing under pressure are higher than those of the control samples without pressure,ranging in ratio from 0.5%to 20.2%and 7.1%to 52.3%,respectively,and are influenced by the initial loading age(ILA)and stress strength ratio(SSR).The SSR during curing should not exceed 80%.2)The earlier the ILA is,the higher the total strain becomes.The higher the SSR applies,the larger the total strain gets.The creep strain increases with the increase of SSR and can be described by Burger’s viscoelastic creep model.When SSR is less than 80%,the earlier the ILA is,the smaller the creep strain becomes after the last step-loading.3)The stability of the early age backfill column under pressure can be monitored based on the change of ultrasonic pulse velocity(UPV)and electrical resistivity.

Effect of Curing Conditions on the Durability of Ultrahigh Performance Concrete under Flexural Load

We experimentally investigated the effect of curing conditions on the durability of UHPC under flexuralload.Moreover,the mechanisms of the effect of curing conditions were revealed from the microstructuralpoint of view with environmentalscanning electron microscopy（ESEM）and X-ray computerized tomography（X-ray CT）.The experimentalresults show that the flexuralload has negative influence on the durability of UHPC,but UHPC stillexhibits excellent durability under flexuralload.Besides,the curing conditions do show influences on the durability of UHPC.Compared with standard and steam curing,oven curing led to a lower chloride resistance and freeze-thaw performance of UHPC.The microstructure of UHPC paste was detected with ESEM.It is revealed that,compared with standard and steam cured UHPC,the lower reaction degree and internalmicrocracks are the causes for the lower chloride resistance of oven cured UHPC.The defects distribution in UHPC before and after freeze-thaw action was investigated with X-ray CT.The number of defects in oven cured UHPC increases the fastest during the freeze-thaw action due to its more defective microstructure

Effects of Shale and CaO Incorporation on Mechanical Properties and Autogenous Deformation of Early-age Concrete

The pre-soaked shale employed as an internal curing agent and CaO employed as expansion agent were incorporated into concrete to investigate their effects on the mechanical properties and autogenous deformation of early-age concrete.We have conducted the relevant tests for setting time,mechanical properties,internal relative humidity and autogenous deformation of early-age concrete with shale or/and CaO incorporation.The results indicate that the set behavior is delayed by shale addition but is accelerated with CaO.The shale addition firstly enhances and subsequently decreases the strength,but CEA addition has a weakening effect.Additionally,shale or/and CaO incorporation deteriorates the elastic modulus.The shale and CaO incorporation significantly improve the internal relative humidity of concrete.The internal curing efficacy of shale could synergistically mitigate the autogenous shrinkage,that is,could enhance the expansion of CaO and then greatly reduce the contraction,which is significantly beneficial to impede the shrinkage-introduced cracks of early-age concrete.

Cost-benefit Analysis of Baking under Different Tobacco Loading Patterns

[Objective] This study aimed to analyze the baking cost and benefit under different tobacco loading patterns, and to further explore labor-and cost-saving measures for modern tobacco agriculture. [Method] The cost and benefit of baking under three different tobacco loading patterns in a bulk curing barn were analyzed from the perspectives of baking equipment cost, labor cost, energy consumption and comprehensive income. The upper, middle and lower tobacco leaves were detected. [Result] Compared with conventional loading pattern, loose-leaf stacking and needle- style tobacco clip loading patterns significantly reduced the labor costs and energy costs during tobacco curing. The comprehensive benefits of tobacco clip and looseleaf stacking loading patterns were higher than that of conventional loading pattern, and the benefits of dry tobacco was improved by 0.67 and 1.07 yuan/kg, respec- tively. The benefit of loose-leaf stacking loading pattern was higher than that of to bacco clip loading pattern, [Conclusion] Among the three loading patterns, the loading pattern of loose-leaf stacking is most worthy of popularization and application.

不同加载速率下蒸养混凝土单轴压缩声发射特性研究

为研究加载速率对蒸养混凝土受压破坏过程中声发射特性的影响,针对蒸养混凝土试件开展3种加载速率工况单轴压缩试验,并利用声发射技术对试验全过程进行动态监测,分析了不同加载速率下蒸养混凝土内部声发射特征参数的变化特征。结果表明:不同加载速率下蒸养混凝土受压破坏过程的声发射振铃计数变化呈现接触期、平静期、陡增期的三阶段变化规律,随加载速率增加,振铃计数率和能量计数率峰值逐渐增大,累计振铃计数和累计能量计数逐渐减小。低加载速率下,声发射幅度分布较为稀疏,内部损伤信号多而分散;高加载速率下,声发射幅度分布较为密集,内部损伤信号少而集中。声发射Ib值随加载进程呈现上升、波动和下降的演化过程,随加载速率的增加,混凝土试件破裂模式由剪切破坏向拉伸破坏的趋势演变。

溶剂负载摩擦法评价UV胶印油墨印品固化程度

目的UV油墨固化程度是印品质量的关键影响因素,开发新型UV油墨固化程度评价方法,用以准确、直观地判断墨层固化程度,指导印刷工艺条件优化。方法通过调控墨层的UV固化光能量,制备系列不同固化程度的胶印印品,以间歇红外法测定墨层的双键转化率定量分析固化交联反应的程度,进一步以墨层在不同溶剂下的摩擦次数建立墨层固化等级的评价方法。结果不同UV固化能量下的样品,具有不同的双键转换率,依据不同比例的乙醇与水混合溶剂下的印品耐磨次数可以判定出印品的固化程度。结论采用溶剂负载摩擦法主观经验判定依赖性低,可实现对UV油墨印品的整体油墨固化程度进行判定,具有良好的生产应用价值。

环境侵蚀性桩基废弃泥浆高效脱水固化试验研究

桩基等工程施工过程会产生大量废弃泥浆,其含水率高、粘粒含量高且具有污染性,一般呈强碱性。在我国双碳目标的政策背景下,废弃泥浆处理及资源化利用势在必行。本文依托甘肃某公路工程项目,取施工现场废弃泥浆进行室内试验,分别采用聚合氯化铝(PAC)、阴离子型聚丙烯酰胺(APAM)和复合絮凝剂对废弃泥浆进行絮凝脱水试验,得到了复合絮凝剂最佳掺配比为每500 mL废弃泥浆中添加PAC 3.5 g+APAM 22 mL。采用复合固化剂(CG-T1和水泥)对废弃泥浆底泥进行固化试验,通过加州承载比和无侧限抗压强度评价了其固化效果,结果表明,CG-T1对强度的提升作用较小,水泥可以有效提高固化土的强度。考虑经济和环保效益,研究了复合固化剂固化效果,提出了复合固化剂最优配比,研究结果可指导现场废弃泥浆高效环保处理后应用于路基填筑。

响应面法优化烤后烟叶回潮技术

为优化装烟回潮工艺,以湘烟7号为试验材料,回潮协调度为评价指标,通过对照试验分别对装烟密度、回潮时间、回潮湿度进行优化筛选,随后以回潮协调度以及回潮均匀性为评价指标,通过响应面法优化参数。结果表明,在装烟密度为50 kg·m-3、回潮时间为14 h、回潮湿度为77%的工艺参数条件下,回潮效果最优,此时烟叶的回潮协调度为98.95%,回潮均匀性为97.24%。本研究基于响应面法通过多次回潮试验,得出最优工艺参数,为烤烟回潮工艺的制定提供理论依据。

检测过程对48K大丝束碳纤维拉伸弹性模量的影响

以中复神鹰SYT45S-48K碳纤维作为研究对象、SYT55S-12K碳纤维作为试验参比,从预加载荷、固化温度、加载速率、加捻四个方面探讨检测过程对48K大丝束碳纤维拉伸弹性模量的影响。结果表明,对试样施加初始载荷约为破坏载荷的5%,加载速率为15 mm/min、样条固化温度为130℃、加强片固化温度为120℃时,其拉伸弹性模量不低于252 GPa,且与第三方检测机构对标结果一致。

荷载作用下混凝土的碳化深度

通过养护28 d和90 d混凝土的快速碳化实验,研究了未加载混凝土的碳化经时模型;在不同荷载率(25%和50%)下和不同养护龄期时研究了混凝土的抗碳化能力.结果显示:未加载混凝土的碳化经时模型符合指数关系;施加荷载后混凝土的抗碳化能力显著劣化,而延长养护龄期可提高混凝土的抗碳化能力.

装烟密度对密集烘烤过程中烟叶主要生理指标的影响

采用河南农业大学设计的电热式温湿自控密集烤箱,对不同装烟密度和变黄温度下烟叶的淀粉酶、过氧化物酶(POD)、抗坏血酸过氧化物酶(AAO)及叶绿素的动态变化作了探索性研究。结果表明:整个烘烤过程中,装烟密度为5 5～6 5kg/m3的处理烟叶淀粉酶、过氧化物酶、抗坏血酸过氧化物酶的活性相对较高。

不同装烟方式对烟叶挥发性性致香物质含量的影响

为研究密集烘烤中不同装烟方式对烤后烟叶挥发性致香物质含量的影响,采用4 cm宽烟夹、10 cm宽烟夹、烟框和正常挂竿4种装烟方式烘烤,测定烟叶中性致香物质含量的差异。结果表明,不同装烟方式对中性致香物质有显著影响(P<0.05),采用烟夹夹持烘烤可以使烟叶内挥发性致香物质含量有明显提高,并且10 cm宽烟夹夹持烘烤处理的类胡萝卜素类、苯丙氨酸类、棕色化产物类、类西柏烷类、新植二烯等香气物质含量均高于正常挂竿处理。

普通标准化烤房改造为密集式烤房适宜装烟密度研究

将标准化气流上升式普通烤房（2．7m×2．7m）改造为密集式烤房，按几种不同的编烟方式和竿距组合装烟进行烘烤，并分析烤后烟叶的内外品质，结果表明，普通1．5m长的烟竿，烟叶每束3片捆绑，每竿50束捆绑，竿距14-16cm效果较好。

密集烤房装烟密度和变黄期风机转速对烟叶淀粉降解及经济性状的影响

以云烟87中部叶为试验材料,研究了密集烤房装烟密度和变黄期风机转速对烟叶淀粉降解和经济性状的影响。结果表明,装烟密度55～65 kg/m3配合变黄期风机转速960 r/min有利于淀粉的降解和烤后烟叶质量的形成。淀粉含量随着烘烤过程的进行逐渐降低,还原糖含量随着烘烤过程的进行逐渐升高。互作效应对烟叶淀粉和还原糖含量的影响在42℃末、47℃末、54℃末及烤后达到极显著水平。装烟密度和变黄期风机转速对烟叶总氮和烟碱含量的影响分别达到极显著水平。装烟密度55～65 kg/m3配合变黄期风机转速960 r/min烤后烟叶均价最高。

不同烟夹装烟方式对密集烤房烘烤效果的影响

为探索烟叶烘烤环节新的装烟方式,充分发挥密集烘烤的优势,从装烟效率、烘烤成本和烤后烟叶经济性状,对针式烟夹、弹簧式烟夹、发夹式烟夹与常规挂竿进行了对比研究.结果表明,烟夹夹持与普通挂竿相比,烤后烟叶外观质量高,上中等烟比例和橘黄烟率较高,每千克干烟用工费和烘烤成本较低,均价提高.经过对3种烟夹对比研究,针式烟夹效果最好,方便快捷,值得在生产上推广.

密集烤房不同装烟方式对烟叶质量及效益的影响

为优化密集烤房装烟方式,充分发挥烤烟密集烘烤的优势,对散叶烘烤、烟夹持烟、烟竿编烟3种装烟方式烤后烟叶的外观质量、评吸质量、经济性状及烘烤能耗成本进行了比较研究。结果表明,烟夹持烟烤后烟叶橘黄烟比例比烟竿编烟烘烤高11.11%,散叶烘烤的杂色烟比例明显低于烟夹持烟和烟竿编烟;散叶烘烤和烟夹持烟烤后烟叶的评吸质量均优于烟竿编烟;散叶烘烤烟叶的中上等烟比例和均价最高;烟夹持烟烘烤的耗煤、耗电成本最低。综合烤后烟叶的经济性状和能耗成本,以烟夹持烟的效益最好。因此,在其他烘烤设施和烘烤技术配套的前提下,烟夹持烟可以替代传统的烟竿编烟;散叶烘烤是密集烤房装烟方式的发展方向之一。

密集烘烤不同装烟方式对烤后烟叶中性致香物质含量的影响

为了探索密集烤房不同装烟方式与烤后烟叶香气物质的关系,进行了密集烤房挂竿、散叶、插签和烟夹4种装烟方式的试验。结果表明:1)不同装烟方式烤后烟叶中性致香物质总含量大小为散叶>插签>挂竿>烟夹,与挂竿处理相比,散叶处理的中性致香物质总量增加了10.94%,插签处理增加了8.48%。2)散叶处理在类胡萝卜素降解产物类、棕色化反应产物类、苯丙氨酸降解产物类、类西柏烷降解产物类以及新植二烯等香气成分类上均有增加;插签处理的中性香气物质增加主要在类胡萝卜素降解产物类、新植二烯含量上,分别增加了8.54%和12.16%;烟夹处理苯丙氨酸类致香物质的苯甲醛、苯甲醇、苯乙醛、苯乙醇含量均有所增加。综合认为,散叶和插签装烟方式可以增加烤后烟叶的中性致香成分含量,烟叶的香气物质含量与装烟方式密切相关。

装烟密度对密集烘烤中上部烟叶香气质量的影响

以烤烟品种云烟87中部叶和上部叶为试验材料,研究密集烤房3种装烟密度(42.09 kg/m3、56.12 kg/m3和70.15 kg/m3)对烤后烟叶香气质量的影响。结果表明,密集烤房适当增加装烟密度能在一定程度上增加烤后烟叶类胡萝卜素降解产物、类西柏烷类、美拉德反应产物、新植二烯及其香气物质总量,但苯丙氨酸类有所减少;中部烟叶以装烟密度56.12 kg/m3时烤后烟叶新植二烯和香气物质总量最高,其余香气物质含量略低于70.15 kg/m3;上部烟叶随着装烟密度的增加,香气物质总量有升高的趋势,以装烟密度70.15 kg/m3时香气质量改善效果最好。