Flexural stability analysis of composite panels reinforced with stiffener integral woven preforms

3D weaving exhibits to be a guaranteeing innovation in delivering integrated near net shaped structures that might overcome the current issue of delamination and assembly cost. This paper highlights one such technique of producing preforms with integrally woven stiffener sections that can be used as a reinforcement material for composite panels. The woven performs were fabricated using high performance polyester yarns as a raw material and further consolidated to composite structures using epoxy resin. The flexural analysis of the composite panels developed from these performs revealed that the structures have better bending rigidity and structural integrity without any possibility of delamination prone failures. Investigations on fracture morphology were conducted to understand the composite failure mechanism and the structural deformation of the structures during loading. From the findings, it was evident that the polyester-epoxy material combination exhibited substantial residual strength and toughness properties.     

Modelling the thermal resistance of woven fabrics

Thermal resistance of fabrics is an important property influencing an ability of fabrics to protect the human body against cold. In this paper the model of the thermal resistance of woven fabrics is elaborated. Next, an experimental verification was carried out on the basis of the results for 26 cotton woven fabrics of plain weave as well as for 18 cotton fabrics of weaves different to plain. The experiment confirmed that there is a statistically significant and strong correlation between the real values of the fabric thermal resistance measured by means of Alambeta and the predicted value calculated by means of the elaborated model.     

Geometrical modeling of 3D woven spacer fabrics as reinforcement for lightweight sandwich composites

Lightweight sandwich composites mainly utilize hollow textile preforms as their reinforcement. The production of such structures with desired mechanical properties requires monitoring of its repeat unit weight and fibre volume fraction (FVF) from designing stage itself. In this work, mathematical expressions have been developed using fabric geometrical parameters which can calculate the areal density and FVF of a repeat unit of 3D hollow woven structures. Five samples each of trapezoidal and rectangular spacer configurations were produced with different cell structural parameters and materials to validate the model. It was found that the computed results for both the weight and FVF were in good correlation with experimental results, with prediction accuracy being more than 90% in all cases. It was also found that with increase in the cell dimensions, the FVF of the expanded fabric decreases.     

Modelling the geometry of the repeat unit cell of three-dimensional weave architectures

The three-dimensional (3D) weaving process offers the ability to tailor the mechanical properties via design of the weave architecture. One repeat of the 3D woven fabric is represented by the unit cell. The model accepts basic weaver and material manufacturer data as inputs in order to calculate the geometric characteristics of the 3D woven unit cell. The specific weave architecture manufactured and subsequently modelled had an angle interlock type binding configuration. The modelled result was shown to have a close approximation compared to the experimentally measured values and highlighted the importance of the representation of the binder tow path.     

三维正交机织物织造及复合材料成型工艺研究

详细阐述三维正交机织物的结构特征、织造原理及织造工艺,以三维正交机织物为增强体、环氧树脂为基体,采用真空辅助树脂传递模塑(VARTM)工艺成型,制成复合材料,并分析其内部结构。结果表明:由普通织机改造的多综眼多剑杆织机可以织造三维正交机织物,成型后复合材料内的纱线形状和位置未发生明显变化,树脂较好地渗透到织物内部,复合材料具有较高的纤维体积分数。研究结果为进一步研究三维正交机织复合材料的力学性能及应用奠定了基础。     

Generalized geometric modeling of three-dimensional orthogonal woven preforms from spun yarns

Through the thickness mechanical properties of composites have been improved with the advance of 3D woven preforms incorporating through-thickness reinforcement element compared to 3D woven composites from stack of 2D fabrics. In this study, a generalized geometric model considering non-jammed and jammed constructions of 3D orthogonal woven preforms from spun yarns was developed to predict fiber volume fraction (FVF) of structure constituents, preform thickness, preform areal density, and minimum thread spacing (x-, y-, and z-yarn spacing) to achieve jammed construction in terms of weave factor, number of layers, and constituents’ variables (y- and z-yarn sequence, linear densities, packing factor, and fiber volumetric density). Numerical results are presented to demonstrate the generalized model potential as a design tool to achieve broad range of constituents FVF that controls composite performance.     

参数化单胞计算三维编织预制件纤维体积含量

在Pro/E中建立了三维编织预制件的内部单胞、表面单胞和棱角单胞的3D实体模型,并对模型进行了参数化设计。当编织工艺参数改变时能自动生成新的单胞模型,单胞纤维体积由Pro/E的模型分析功能直接输出。提出了基于参数化单胞计算预制件纤维体积含量的公式。计算了长方体形预制件的纤维体积含量,并与实测值进行比较,理论计算与实验结果吻合良好。计算了扇环形预制件的纤维体积含量,为复杂外形预制件纤维体积含量的计算提供了新方法。     

Effect of grafting generations of poly(amidoamine) dendrimer from the sisal fiber surface on the mechanical properties of composites

In order to improve the mechanical properties of sisal fiber-reinforced polypropylene composites, the sisal fibers were grafted with poly(amidoamine) dendrimer and the effects of grafting generations on the mechanical properties of composites were studied. The results reveal that the tensile, flexural, and impact strength of the composites are improved considerably with the poly(amidoamine) dendrimer grafting treatment. For the 2.0 generation treatment with the poly(amidoamine) dendrimer, the tensile, flexural, and impact strength of the composites at 30 wt% fiber loading increase by 29%, 13%, and 54%, respectively. However, the thermal and mechanical properties of the sisal fibers decrease after prolonged grafting treatment.     

延年素纤维混纺织物的开发

利用新研制出的享有"内衣小空调和绿色维他命"美称的延年素功能性纤维与棉、毛混纺交织生产出亚纳米功能呢.该产品是一种集美观、舒适及保健于一体的新型毛精纺面料.文章介绍了延年素纤维的理化特性,并给出了延年素纤维混纺织物的设计方案及纺纱、织造、染整等工序的工艺,为类似功能性纺织品的开发提供了参考.     

利用近红外光纤分析技术检测饲料中粗纤维含量

利用近红外光纤分析技术检测饲料中粗纤维的含量,采用偏最小二乘回归(PLS)方法,分别对光谱进行附加散射校正、变量标准化、一阶导数和平滑处理,建立了饲料中粗纤维含量的预测模型。其中附加散射校正、一阶导数和9点平滑处理定标效果最优。定标集化学分析值与预测值之间的决定系数(Rc2)和标准分析误差(SEC)分别为0.9698和0.1131%,相对分析误差为6.01;验证集化学分析值与预测值之间的决定系数(Rv2)和标准分析误差(SEP)分别为0.9402和0.1536%,相对分析误差为4.04。结果表明,利用近红外光纤分析技术可以比较准确地定量检测饲料中粗纤维的含量。      

主链含柔性链的聚酰亚胺的制备及其在纺织品中的探索性应用

以1,2-双(4-氨基苯氧基)乙烷、1,3-双(4-氨基苯氧基)丙烷、1,4-双(4-氨基苯氧基)丁烷三种主链含柔性链的二胺单体和3,3,′4,4′-二苯醚四羧酸二酐进行缩聚反应,制得聚酰胺酸溶液,涂层于芳纶1414基布。对经聚酰亚胺处理后织物的力学性能、热性能及防紫外辐射性能进行测试,结果表明强力有所降低,热性能稍有提高,防紫外辐射性能有了显著提高。     

Enzymic degradation and nature of the endosperm cell walls of germinating sorghums and barley

β-(1·3)(1·4)-Glucans are the major components of isolated endosperm cell walls of both sorghum and barley grains and the concentration declines from 75% in unmalted barley walls to 32% in those of the 6-day malts. In sorghums over the same period, the reduction was from 72 and 68% to 54 and 62% in varieties L187 and SK5912, respectively. Following germination wall pentosans, while enhanced in barley, decreased in sorghum. The enzymes which were unable to hydrolyse the walls of sorghum to release sugars (unlike those of barley) did so after the walls had been solubilised in alkali. Cellobiose accounted for 43% of the hydrolysates of the alkali-solubilised walls when incubated with sorghum malt enzymes and 79% when barley enzymes were used. Laminaribiose was not detected in either case which indicates that the polysaccharide of the sorghum walls is largely of a ‘cellulosic’ nature. Preliminary evidence suggests that fuco-xyloglucan may contribute to the resistance of the sorghum endosperm cell walls to enzymic attack during germination.     

含纳米TiO2毛织物的抗菌性能研究

结合现行织物抗菌性能的试验方法和标准,设计了光催化型抗菌织物的测试方法:采用抑菌圈法定性研究了毛织物与纳米TiO2复合后的抗菌性能,通过正交试验方案,以菌落计数法定量探讨了负载纳米TiO2毛织物的抗菌最佳工艺.结果表明:毛织物负载纳米TiO2适量时,光强是影响织物抗菌性的一个重要因素,菌悬液的浓度对织物抗菌性有直接影响;通过正交试验分析:光强为抗菌性的最大影响因素,TiO2负载量次之,光照时间最小.TiO2分散液5 mL,光照时间18 h,紫外光强6.6 μW/cm2为最佳处理方案,杀菌率达到96.57%.     

沙棘籽粕原花青素制备、体外抗氧化及细胞活力评价

本实验优化了沙棘籽粕原花青素的提取方法,条件为80%乙醇,提取温度35℃,液料比8∶1 m L/g,时间1.5 h,p H3.0,在该条件下的原花青素提取率为（97.31±0.48）mg/g沙棘籽粕;对提取得到的原花青素提取物进行了DPPH自由基和羟自由基清除能力实验,并分析得到IC₅0,发现沙棘籽粕原花青素提取物的DPPH自由基清除能力较维生素C强;羟自由基清除能力较弱;MTT法测定了沙棘籽粕原花青素提取物对小鼠B16黑色素瘤细胞活力的抑制作用,分析得到24、48、72 h处理时间下提取物IC₅0分别为542.78、199.25、82.58μg/m L。结论:沙棘籽粕提取物对小鼠B16黑色素瘤细胞具有一定的抑制作用,随着剂量和时间的增加,呈逐渐增强的趋势。      

超高效液相色谱大体积流通池荧光法检测花生油中黄曲霉毒素B1的不确定度评定

目的 评定超高效液相色谱大体积流通池荧光法测定花生油中黄曲霉毒素B1含量的不确定度.方法 依据GB 5009.22—2016《食品安全国家标准食品中黄曲霉毒素B族和G族的测定》第三法无衍生器法测定花生油中黄曲霉毒素B1(aflatoxin B1,AFTB1),根据JJF 1059.1—2012《测量不确定度评定与表示》...     

Magnetic manipulation device for the optimization of cell processing conditions

Variability in human cell phenotypes make it's advancements in optimized cell processing necessary for personalized cell therapy. Here we propose a strategy of palm-top sized device to assist physically manipulating cells for optimizing cell preparations. For the design of such a device, we combined two conventional approaches: multi-well plate formatting and magnetic cell handling using magnetite cationic liposomes (MCLs). From our previous works, we showed the labeling applications of MCL on adhesive cells for various tissue engineering approaches. To feasibly transfer cells in multi-well plate, we here evaluated the magnetic response of MCL-labeled suspension type cells. The cell handling performance of Jurkat cells proved to be faster and more robust compared to MACS (Magnetic Cell Sorting) bead methods. To further confirm our strategy, prototype palm-top sized device “magnetic manipulation device (MMD)” was designed. In the device, the actual cell transportation efficacy of Jurkat cells was satisfying. Moreover, as a model of the most distributed clinical cell processing, primary peripheral blood mononuclear cells (PBMCs) from different volunteers were evaluated. By MMD, individual PBMCs indicated to have optimum Interleukin-2 (IL-2) concentrations for the expansion. Such huge differences of individual cells indicated that MMD, our proposing efficient and self-contained support tool, could assist the feasible and cost-effective optimization of cell processing in clinical facilities.     

Combining the observation of cell morphology with the evaluation of key inflammatory mediators to assess the anti-inflammatory effects of geranyl flavonoid derivatives in breadfruit

Ligation of the receptor for advanced glycation end products (RAGE) is critical for monocyte activation involved in diabetic inflammation. In this study, the effects of the geranyl flavonoid derivatives (6-geranyl-7,4′-dihydroxyflavanone, AC-1; 4,2′,4′-trihydroxy-3′-[6-hydroxy-3,7-dimethyl-2(E),7-octadienyl]chalcone, AC-2; 3,4,2′,4′-tetrahydroxy-3′-geranyldihydrochalcone, AC-3; 4,2′,4′-trihydroxy-5′-geranyldihydrochalcone, AC-4) isolated from the fruit of Artocarpus communis (breadfruit) on the human THP-1 monocyte (THP-1) activation stimulated by S100B, a ligand of RAGE, were evaluated. The morphology of S100B-induced THP-1, which may be essential for the elucidation of the functional role of S100B in monocyte activation was investigated. We also directly demonstrated that S100B-induced THP-1 exhibited the morphological characteristics of inflammation, which were inhibited by the addition of AC-2, AC-3 or AC-4. Moreover, AC-2, AC-3 or AC-4 inhibited S100B-induced ROS generation, mRNA expression of inflammatory mediators (COX-2, TNF-α, IL-6 and RAGE) and IL-6 secretion. Thus, geranyl flavonoid derivatives of breadfruit may have potent implications to prevent diabetic inflammation.