基于离散元法的椰糠颗粒建模及仿真参数标定

为确定椰糠在离散元模拟过程中合理的仿真参数,本文基于离散元法Hertz-Mindlin（no slip）接触模型在仿真软件EDEM 2018中建立椰糠颗粒模型并生成颗粒工厂,通过测量比对物理试验和仿真试验椰糠堆积角的方法对其仿真参数进行标定。首先通过物理试验测得椰糠堆积角、堆积密度等本征参数,利用EDEM 2018内嵌GEMM数据库以及相关文献,综合分析得到椰糠待标定因素的高低水平;然后进行Plackett-Burman试验设计筛选出对椰糠堆积角影响显著的因素依次为：椰糠-椰糠静摩擦系数、椰糠-椰糠滚动摩擦系数和椰糠剪切模量;再进行Box-Behnken试验设计建立堆积角与3个显著性影响因素的回归模型,运用Design expert软件优化功能,以堆积角物理试验45.69°为目标,对回归方程寻优求解,得到显著性影响因素最佳组合：椰糠剪切模量为1.44 MPa,椰糠-椰糠静摩擦系数为1.11,椰糠-椰糠滚动摩擦系数为0.15;最后通过试验验证表明此组合参数可用于椰糠物料的离散元仿真,能为椰糠输送、混合等机械装备的设计研发提供理论参考。     

不同椰衣栽培介质对西瓜苗生长及生理特性的影响

研究不同的椰衣栽培介质对西瓜发芽的影响等，对于开展椰衣栽培介质基质化的应用具有重要意义。采用海南3市(县)5镇的11种椰糠为基础及配置2种(MIX1、MIX2)复合基质为测试材料，对椰衣介质13个处理的浸出液分别进行西瓜种子发芽实验、西瓜苗生长实验及相关生理测评等。结果表明：复合基质处理能保证西瓜苗生长，pH、EC值的大小是筛选优良椰衣复合基质的关键。椰衣介质MIX1处理是适宜西瓜生长发育的复合基质。     

椰衣纤维的蒸汽爆破处理技术

采用蒸汽爆破技术处理椰衣纤维,通过化学分析方法及扫描电镜、红外光谱等现代分析手段分析蒸汽爆破处理前后椰衣纤维化学组分和形态结构的变化,并初步探讨蒸汽爆破在椰衣纤维处理中的工艺及原理。结果表明:蒸汽爆破处理技术能够有效减少椰衣纤维中的木质素、果胶等杂质,提高纤维素含量;同时,高温高压水蒸气瞬间泄压过程可以破坏纤维素中原纤间的结合力,改善纤维的形态结构,提高化学试剂的可及度,改善纤维化学反应性能。     

不同基质对香蕉组培苗生长及光合特性的影响

用椰糠与砖红壤土配成的6种不同基质栽培巴西香蕉组培苗,进行生长效果的比较；采用Li-6400便携式光合测定仪测定组培苗的净光合速率(pn)、蒸腾速率Tr等的日变化,通过相关性分析不同光合参数对净光合速率(pn)日变化的影响.结果表明:以椰糠:壤土=1:2配方对组培苗的生长效果最好；组培苗在不同基质下的净光合速率(pn)、蒸腾速率、气孔导度等变化趋势相似,其中以椰糠:壤土=1:2处理的数值最高,椰糠:壤土=4:1最低,胞间CO2浓度的数值则相反.6种基质栽培的香蕉组培苗以T2,即椰糠:壤土=1:2配制最适合香蕉组培苗生长.     

花卉栽培介质不同配方理化性状比较研究

通过对椰糠、珍珠岩、草炭和保水剂不同配比的物理性质(容重、孔隙度和持水量等),以及pH值、EC值和有机质、全效N、P、K、速效N、P、K和缓效K的含量进行测试。根据理想栽培介质对物理化学性状的要求,以理想介质适宜指标为标准,初步评判不同混合基质,得出最佳的三种不同配比组合为:80%椰糠+20%珍珠岩、75%椰糠+20%珍珠岩+5%草炭和80%椰糠+20%珍珠岩与保水剂的质量比为100:1。     

椰味膳食纤维营养果冻的加工工艺

以椰子粉、不溶性椰子膳食纤维、卡拉胶为主要原料设计出制备椰味膳食纤维营养果冻的实验方案和工艺流程,确定了椰味膳食纤维营养果冻的最佳工艺配方,最后还制定了产品质量标准。采用该配方制备的果冻,营养价值高、椰味浓郁、口感爽滑。     

纤维燃料乙醇生产中木糖发酵的研究进展

木糖是木质纤维质水解产物中含量仅次于葡萄糖的单糖,由半纤维素水解生成.研究表明,将本质纤维素原料中的木糖发酵生成乙醇,可提高纤维燃料乙醇的转化效率25%左右.天然菌种在发酵过程中具有副产物多、乙醇得率低、易污染、耐乙醇能力差等缺点,难以工业化应用.近年来许多研究者构建了可以高效代谢五碳糖和六碳糖的基因重组菌.虽然这些重组菌株在木糖转化酒精方面均显示出良好的应用前景,但仍存在诸多问题.本文介绍了近年来代谢工程改造微生物菌种发酵木糖生产酒精的研究进展,以期为利用农作物秸秆转化燃料乙醇研究提供参考依据.     

桉树组培瓶苗轻型基质移栽技术研究

桉树作为南方重点发展的工业用材林树种,其优质种苗需求量非常大。试验研究了木屑、椰糠、泥炭土和珍珠岩作为桉树组培苗的轻型基质。试验显示木屑:椰糠:泥炭土:珍珠岩为2:2:3:3的配方桉树组培苗的移栽成活率最高;木屑:椰糠:泥炭土:珍珠岩为5:3:2:2的配方每株根长度的平均值达到最高。但考虑到育苗成本,选择木屑:椰糠:泥炭土:珍珠岩为2:2:2:3的配方为移栽基质,其移栽成活率最高达90.24%,每株根长度的平均值达到中上水平。     

不同基质对中苗期红掌生长及体内氮、磷、钾、钙、镁养分吸收利用的影响

通过不同体积比的粗砂、椰衣、椰糠、花生壳、谷壳的组合对中苗期红掌品种“热情”的处理,研究了不同基质配比对中苗期红掌植株的生长以及N、P、K、Ca、Mg养分吸收利用的影响,结果表明：配方为V椰糠∶V谷壳∶V花生壳＝2∶1∶1的栽培基质其各项理化性状更优,且最有利于中苗期红掌的生长及干物质的积累;中苗期红掌地上部及地下部N、P、K、Ca、Mg的利用率之间无显著规律性,但上述元素的积累量也在配方为V椰糠∶V谷壳∶V花生壳=2∶1∶1的栽培基质上最高。     

香蕉组培苗基质配方的筛选

以椰糠、砖红壤、有机肥和河沙作为基质材料,用正交法设定出16种配方,对巴西香蕉组培苗进行营养杯栽培试验,通过测试分析基质理化性状、幼苗叶片营养元素含量和生长指标,确定出最佳的基质配方。结果表明：椰糠与砖红壤是影响基质理化性状、植株生长与大中量养分积累的主要因素,砖红壤是影响微量元素锰、锌、镍、镉积累的主要因素,有机质是影响铜素积累的主要因素。椰糠混配处理显著改善了基质的pH值、容重等理化性状,促进了植株生长,增加了叶片养分积累。其中椰糠 ∶ 泥土 ∶ 有机肥 ∶ 河沙=4 ∶ 0 ∶ 0.05 ∶ 0.1     

不同基质配比对酸柚苗生长的影响

通过设置不同基质配比处理,筛选出较适合酸柚苗的基质配方,为无籽蜜柚优质砧木繁育提供理论依据。以椰糠、表土、甘蔗灰和菜籽饼为原料,按不同体积比配制9种栽培基质进行容器育苗,并测定各基质理化性质及苗木生长生理指标。结果表明:不同基质配比处理对酸柚苗的苗高、径粗、叶片增加数、总生物量及叶绿素含量方面影响显著,其中T5(1/3椰糠、1/3表土、1/3菜籽饼)综合表现最好,其次为T2(2/3椰糠、1/6表土、1/6菜籽饼)和T9(2/3表土、1/6甘蔗灰、1/6菜籽饼),表现较差的为T1(2/3椰糠、1/6表土、1/6甘蔗灰)、T4(1/3椰糠、1/3表土、1/3甘蔗灰)和T7(1/6椰糠、2/3表土、1/6甘蔗灰)。结合苗木生长状况及基质成本,认为体积比为1/3椰糠、1/3表土、1/3菜籽饼的栽培基质较适合酸柚苗生长。      

Effect of fiber length on mechanical behavior of coir fiber reinforced epoxy composites

Fiber reinforced polymer composites have played a dominant role for a long time in a variety of applications for their high specific strength and modulus. The fiber which serves as a reinforcement in reinforced plastics may be synthetic or natural. To this end, an investigation has been carried out to make use of coir, a natural fiber abundantly available in India. Natural fibers are not only strong and lightweight but also relatively very cheap. The present work describes the development and characterization of a new set of natural fiber based polymer composites consisting of coconut coir as reinforcement and epoxy resin as matrix material. The developed composites are characterized with respect to their mechanical characteristics. Experiments are carried out to study the effect of fiber length on mechanical behavior of these epoxy based polymer composites. Finally, the scanning electron microscope (SEM) of fractured surfaces has been done to study their surface morphology.     

基于衍生化GC-MS法分析不同栽培基质对铁皮石斛代谢的影响

栽培基质是影响铁皮石斛生长的主要因素之一,本研究拟选用松树皮(PB)、椰糠(CC)和松树皮:椰糠(PC,1:1)的复合基质栽培铁皮石斛,基于代谢组学思路探究栽培基质对铁皮石斛茎生长代谢的影响.通过环刀法测定3种基质的物理性质,利用苯酚-硫酸比色法测定铁皮石斛茎的多糖含量,采用硅烷化衍生化法结合气相色谱-质谱法检测铁皮石...     

Coir fiber reinforced polypropylene composite panel for automotive interior applications

In this study, physical, mechanical, and flammability properties of coconut fiber reinforced polypropylene (PP) composite panels were evaluated. Four levels of the coir fiber content (40, 50, 60, and 70 % based on the composition by weight) were mixed with the PP powder and a coupling agent, 3 wt % maleic anhydride grafted PP (MAPP) powder. The water resistance and the internal bond strength of the composites were negatively influenced by increasing coir fiber content. However, the flexural strength, the tensile strength, and the hardness of the composites improved with increasing the coir fiber content up to 60 wt %. The flame retardancy of the composites improved with increasing coir fiber content. The results suggest that an optimal composite panel formulation for automotive interior applications is a mixture of 60 wt % coir fiber, 37 wt % PP powder, and 3 wt % MAPP.     

添加酶制剂对饲用苎麻与麦麸混合青贮品质的影响

为了探究酶制剂对苎麻混合青贮品质的影响,本试验在苎麻与麦麸(80%苎麻+18%麦麸+2%蔗糖)混合青贮中分别添加10 mL蒸馏水(对照组)、纤维素酶2 g/kg、纤维素酶2 g/kg+半纤维素酶0.4 g/kg、纤维素酶2 g/kg+半纤维素酶0.4 g/kg+果胶酶0.7 g/kg,30天后开包取样分析各项指标。结果表明,苎麻与麦麸混合青贮发酵品质和营养品质均较好。与对照相比,添加酶制剂显著提高了碳水化合物、干物质和粗蛋白含量(P<0.05),显著降低了中性洗涤纤维、酸性洗涤纤维、粗纤维的含量和氨态氮/总氮比值(P<0.05),但是对pH值、乳酸、乙酸和丙酸含量无显著影响(P<0.05)。本试验条件下,添加酶制剂能够有效提高苎麻混合青贮的品质,单独添加纤维素酶与复合酶制剂无显著性差异,从节约成本角度考虑,单独添加纤维素酶组为最佳选择。     

Physicochemical and functional characterization of wheat milling co-products: Fine grinding to achieve high fiber antioxidant-rich fractions

Milling of wheat produces co-products rich in dietary fiber, micronutrients and phytochemicals which can be used to integrate healthy functional foods. In the study different co-products including bran, shorts, and red dog were identified by physicochemical and functional analyses. The results showed that the fat, protein and starch contents decreased in order of red dog > shorts > bran (P < 0.05). The ash, neutral detergent fiber (NDF), acid detergent fiber (ADF), hemicellulose, water and oil holding capacities (WHC, OHC) were in order bran > shorts > red dog, respectively (P < 0.05). Antioxidant capacity was in order red dog > shorts > bran (P < 0.05). The bran was selected as the co-product with the highest fiber that was finely grounded to four different fractions (>355, 250–355, 180–250, <180 μm) and they were characterized more detail. The fat, protein and starch contents decreased with increasing bran particle size (P < 0.05). The ash, crude fiber, NDF, ADF, hemicellulose and WHC and OHC increased with the increasing bran particle size (P < 0.05). DPPH radical scavenging activity increased with increasing particle size (P < 0.05). The bran fractions 250–355 and >355 μm can be used as high fiber ingredients rich in antioxidants to generate functional foods.     

几种栽培基质对春石斛组培苗驯化的影响

以4个春石斛品种为材料,研究了3种栽培基质对春石斛组培苗炼苗成活率和初期生长的影响。结果表明:4种春石斛在3种基质中的成活率、生长量及营养元素积累方面均有显著差异,水苔+椰丝是本试验中表现最佳的基质。在成活率方面,91#、94#在水苔+椰丝中成活率最高,分别达到89%和88%;96#在水苔中成活率最高,仅为34%,98#在水苔+椰丝和水苔中成活率最高,均为35%。在生长量方面,91#、94#、96#在水苔中的相对生长量最高,98#在水苔+椰丝中的相对生长量最高。在营养元素积累方面,91#在3种基质中的表现均差,94#在木屑和水苔+椰丝中的表现较好,96#在水苔中表现最好,98#在木屑中表现最好。上述研究结果可为节约春石斛规模化生产中成本、提高产品质量提供参考。     

椰子水的自然预发酵条件对细菌纤维素合成的促进性影响

细菌纤维素(Bacterial Cellulose,BC)生产中原料椰子水通常经自然预发酵后再使用,对提高BC产量有重要作用。本研究从椰子水产地、预发酵时间、自然预发酵环境3个方面探究了预发酵过程对促进BC合成的必要性和确切性。以预发酵后的椰子水为BC发酵的培养基原料,接种椰冻驹形氏杆菌(Komagataeibacter nataicola)Y19进行BC发酵。结果表明:不同产地的椰子水、经不同预发酵环境、不同预发酵时间后均能显著促进BC合成,对BC产量的增加均有较大影响。在实验室环境预发酵1~3 d时,不同产地椰子水的促进作用均显著,其中产自越南的椰子水在预发酵第2天时BC产量增幅最高,达到对照(新鲜椰子水)的10.8倍;在椰子加工厂区环境进行预发酵时,只需1 d,其BC产量即达最大14.48 g/L,为对照的25.0倍。说明预发酵环境对BC产量增幅影响最大。本文首次阐明椰子水预发酵过程对促进BC合成的必要性和确定性,为进一步揭示椰子水预发酵的本质变化及其对BC发酵调控的影响机制奠定了前期理论基础。      

Effect of coir fiber content and compatibilizer on the properties of unidirectional coir fiber/polypropylene composites

The main objective of this research was to study the effect of fiber content variation and stearic acid (SA) treatment on the fundamental properties of unidirectional coir fiber (CF) reinforced polypropylene (PP) composites. Several percentages of filler contents were used (10–40 wt %) in order to gain insights into the effect of filler content on the properties of the composites. Coir/PP composites were fabricated by compression molding, and the properties of composites were studied by physico-mechanical and thermal properties. The results from mechanical properties such as tensile strength (TS), tensile modulus (TM) and impact strength (IS) of the CF/PP composites were found to be increased with increasing fiber content, reached an optimum and thereafter decreased with further increase in fiber content. Treatment of the coir with SA as the coupling agent enhanced the mechanical properties, crystallization temperature and crystallinity of virgin PP and water desorption of the resulting composites, resulting from the improved adhesion between the CF and PP matrix. Scanning electron micrographs (SEM) of the tensile fractured samples showed improved adhesion between fiber and matrix upon treatment with SA. Interfacial shear strength (IFSS) of the composites was measured by single fiber fragmentation test (SFFT).