Effect of fiber friction, yarn twist, and splicing air pressure on yarn splicing performance

The impact of fiber friction, yarn twist, and splicing air pressure on mechanical and structural properties of spliced portion have been reported in the present paper. The mechanical properties include the tensile and bending related properties and, in the structural properties, the diameter and packing density of the splices are studied. A three variable three level factorial design approach proposed by Box and Behnken has been used to design the experiment. The results indicate that there is a strong correlation between retained spliced strength (RSS) and retained splice elongation (RSE) with all the experimental variables. It has been observed that RSS increases with the increase in splice air pressure and after certain level it drops, whereas it consistently increases with the increase in yarn twist. The RSE increases with the increase in both fiber friction and yarn twist. It has also been observed that the yarn twist and splicing air pressure have significant influence on splice diameter, percent increase in diameter and retained packing coefficient, but the fiber friction has negligible influence on these parameters. Yarn twist and splicing air pressure has a strong correlation with splice flexural rigidity, where as poor correlation with retained flexural rigidity.     

A theoretical investigation on the generation of strength in staple yarns

In this article, an attempt has been made to explain the failure mechanism of spun yarns. The mechanism includes the aspects of generation and distribution of forces on a fibre under the tensile loading of a yarn, the free body diagram of forces, the conditions for gripping and slipping of a fibre, and the initiation, propagation, and ultimate yarn rupture in its weakest link. A simple mathematical model for the tenacity of spun yarns has been proposed. The model is based on the translation of fibre bundle tenacity into the yarn tenacity.     

Study on thermal treatment of hybrid technical yarns

The present paper reports the impact of thermal treatment on the characteristics of core-sheath type hybrid technical yarns. The core-sheath type hybrid yarns are prepared using DREF-III technology. Polyester and glass multifilaments are used as core components whereas the cotton and polyester staple fibers are the sheath components wrapped around the core filament with different proportions to form a hybrid structure. The thermal treatment is carried out both in dry and in wet state under relaxed condition and the thermal shrinkage, sheath-slipping resistance and tensile and bending properties of hybrid yarns have been studied. Thermal treatment markedly increases the thermal shrinkage and sheath-slipping resistance of hybrid yarns with polyester multifilament in core, but insignificant effect for yarns with glass multifilament in core. Breaking elongation of hybrid yarns with polyester multifilament in core increases with treatment temperature. The hybrid yarns with glass multifilament in core are least affected by thermal treatment.     

Study on characteristics of compact yarns under dynamic state

The dynamic testing conditions simulate actual manufacturing conditions more closely than static testing. In most cases, as results from dynamic tests differ significantly from static tests, dynamic tests are more relevant from the point of view of processing of yarn. The yarns are in motion when they are running on different machines during the production process viz. weaving; knitting etc. Compact ring spun yarns have created a fundamental change how the industry views the ring spinning. The new technology compact yarns such as EliTe® yarns need to be compared with the normal doubled yarns in a dynamic way. This study involves dynamic testing of the EliTe® compact yarns and normal ring spun doubled yarns using CTT (Constant Tension Transport) machine, a versatile test instrument to measure the yarn properties such as dynamic breaking strength, elongation, abrasion, lint, yarn faults (thick, thin places, neps), hairiness etc. EliTe® compact yarns showed higher breaking strength, more elongation, with lesser yarn faults and hairiness, less abrasiveness and less lint generating tendencies during the dynamic testing as compared to the normal ring spun doubled yarns.     

苎麻牵切原理及牵切区断裂点分布的研究

本文主要分析了苎麻单纤维在牵切区内运动及断裂的过程，通过试验考查了断裂点的分布情况。     

两种类型土壤大豆施钾效应

为明确不同类型土壤上大豆施用钾肥的效果，采用田间试验的方法，研究了黑土、白浆土上施钾量对大豆生长发育及产量、品质的影响。结果表明，合理的钾肥用量有利于大豆叶绿素含量的提高，从而增强光合作用，为产量的提高奠定了基础。两种土壤上施钾量(x)与产量(y)呈二次回归关系，黑土： =2516.1+6.6307X-0.0242X2 (Ｒ2 =0.8475 )；白浆土： =2453.1+4.2819X-0.0140X2 (Ｒ2=0.9836 )。根据施钾量与产量的关系，结合肥料的经济效益，黑土上种植大豆的最高施钾量应控制在140kg/hm2以下，白浆土上最高施钾量不宜超过150kg/hm2。钾肥具有降低大豆蛋白质含量，提高脂肪含量的趋势。钾能提高大豆的蛋脂总量，本试验黑土处理3、白浆土处理4蛋白质总量比对照分别提高25.4%和11.1%，脂肪总量分别提高15.3%和14.7%。     

Effects of different brassicaceous host plants on the fitness of Pieris brassicae (L.)

Pieris brassicae (L.) is a destructive cosmopolitan pest of cruciferous crops. It is present wherever its host plants occur and it is considered to be one of the most widely distributed of all the Lepidoptera. We investigated the affect of various host plants on the fitness of P. brassicae to survive, develop and reproduce. We quantified development time, survival and mortality on cabbage (Brassica oleracea capitata), cauliflower (Brassica oleracea botrytis), radish (Raphanus sativus), broccoli (Brassica oleracea italica), and mustard (Brassica campestris) under laboratory conditions. The developmental time from eggs to adult eclosion was the shortest (30.3 days) on cabbage and the longest (38.0 days) on radish. However, adult longevity was significantly (P < 0.001) greatest on cabbage compared with the other host plants tested. Similarly, the developmental rate of P. brassicae was found to be faster on cabbage than other cole crops. Moreover, the lowest immature mortality was evident on cabbage and highest on mustard and radish. Differences in reproductive parameters of the P. brassicae among host plants were analyzed using pseudo-values, which were produced by jackknife re-sampling. The data showed that the higher intrinsic rate of natural increase (0.116 females/female/day) was found on cabbage. Cabbage was recognized as the most suitable host for P. brassicae because of shorter developmental period, higher percentage survival, lower doubling time (6.00), and higher number of adult emergence (29.7%).     

不同花生品种荚果发育及有机物积累动态研究

黄淮区花生不同品种荚果发育动态及有机物积累过程的研究表明，86036－26－1荚果发育早，速度快，持续时间短，海花1号发育晚、速度慢，持续时间长，不同品种籽仁干物重，脂肪及蛋白质积累的差异主要表现在快速增加阶段。86036－26－1籽仁的各种有机物增加快而多，但籽仁脂肪含量及蛋白质含量较低；豫花7号的各种有机物增加较快而多，蛋白质含量和脂肪含量较高。     

杂交粳稻甬优538与常规粳稻秀水134本田期适宜施氮比例探讨

应用混料回归设计,探讨了粳型杂交稻甬优538与粳型常规稻秀水134本田期氮化肥适宜施用比例,初步明确了施肥因子与产量的效应关系。结果表明,甬优538施肥因子对产量的作用效应大小为秆肥苗肥基肥穂肥,秀水134为苗肥基肥秆肥穂肥;甬优538的基肥×穂肥、基肥×苗肥×秆肥、基肥×苗肥×穂肥、苗肥×秆肥×穂肥,秀水134的基肥×穂肥、苗肥×秆肥、苗肥×穂肥、基肥×秆肥×穂肥等因子间互作具有显著的协同促进效应;在因子(Σxi=1)约束条件下,单因子比例水平与产量均呈抛物线关系,其中,对于这2个品种其穂肥曲线起伏幅度最大,不可过量施用;基肥、苗肥、秆肥、穗肥最优配比值,甬优538为31.0∶28.8∶21.4∶18.7,秀水134为24.9∶37.3∶11.5∶26.3。     

甜菜对不同施用部位磷种肥的吸收与利用

用P~(32)示踪法研究结果表明,甜菜在1～2片真叶期已开始吸收磷肥。至叶丛繁茂期,单株绝对吸磷量和对磷肥利用率均明显增高,但单株相对含磷量却明显降低;磷肥施到距种子2、4cm以下可显著提高甜菜对磷肥的利用率。至7月中旬利用率分别达4％和7.9％,比种、肥混施分别提高60％和2倍;磷酸二铵做种肥,其分解产生的NH_4对甜菜有毒害作用,可降低出苗率、保苗率,也影响对磷肥的吸收利用。采用种、肥分层施可缓解和避免NH_4~ 对甜菜的伤害。