Optimization of drafting zone variables in ring spinning for the production of cotton/milkweed blended yarns

Cotton/milkweed (60/40) blended yarn of 29.5 tex has been produced on a ring spinning system. The influence of fibre friction, front zone roller setting and front top roller pressure at speed frame and ring frame on yarn properties has been studied using the Box and Behnken design. The optimum conditions within the processing limits of the machines are established. It is observed that a higher fibre friction gives higher yarn tenacity and lower yarn unevenness, imperfection and hairiness. The roller setting and top roller pressure also influence the yarn properties at speed frame and ring frame. With the increase in roller setting the yarn tenacity increases initially and then decreases, while other yarn properties deteriorate at wider roller settings. The increase in top roller pressure leads to reduction in yarn unevenness, imperfection and hairiness due to better control of milkweed fibres in the drafting zone. In general, blends of cotton/alkali-treated milkweed fibres with moderate to lower roller setting and moderate to higher level of top roller pressure give better results

Spinnability of cotton/milkweed blends on ring, compact and rotor spinning systems

The physical characteristics of cotton/milkweed yarns spun on ring, compact and rotor spinning systems in relation to blend proportion and chemical treatment of milkweed fibres have been studied. During spinning of milkweed fibre blends, greater fibre losses in carding and flies during drafting are observed in further stages. It is observed that amongst the ring, compact and rotor yarns, the compact-spun blended yarns show higher yarn tenacity and elongation values followed by ring and rotor-spun yarns. The rotor-spun blended yarns show lower yarn unevenness, imperfections and hairiness values than compact and ring-spun yarns due to its mechanism of yarn formation. With the increase in milkweed proportion, the yarn quality deteriorates, irrespective of spinning systems due to lack of cohesiveness and brittleness of milkweed fibres, and drastic reduction in yarn quality is noticed for 40/60 cotton/milkweed blend. By considering the effect of chemical treatment of milkweed fibres, it is observed that the alkali-treated milkweed fibre blended yarns show better yarn properties due to improvement in fibre friction and elongation values followed by dyed and untreated milkweed fibres

Optimization of process variables in rotor spinning for the production of cotton/milkweed blended yarns

Cotton/milkweed (60/40) blended yarn of 29.5 tex has been produced on rotor spinning system. The influence of fibre friction, opening roller speed and sliver linear density on rotor yarn properties has been studied using Box and Behnken factorial design and the optimum conditions within the processing limits of the machines are established. The results show that fibre friction is the dominant factor in determining the tensile properties and other properties of rotor-spun yarn. It is observed that a higher fibre friction gives higher yarn tenacity, and lower yarn unevenness, imperfection and hairiness. The opening roller speed also has a greater influence on rotor yarn properties.  With an increase in opening roller speed, the number of points per fibre increases, which results in better fibre separation and improvement in yarn properties. But very high opening roller speed deteriorates the yarn properties and increases the end breakage rate mainly due to fibre breakage and low fibre straightness. Generally, heavier sliver weight leads to higher spinning draft which deteriorates the yarn properties

Analysis of structural properties of cotton/milkweed blended ring, compact and rotor yarns

This study has been conducted to explore the relationship between yarn structure and yarn characteristics of cotton/milkweed (C/M) blended yarns. The fibre migration index values reveal that the milkweed fibres are predominantly in the yarn sheath of C/M 80/20 yarn, whereas it occupies the yarn core in C/M 60/40 and 40/60 combinations as small clusters. Fibre migration studies reveal that the compact spun yarns have higher fibre migration factor which is responsible for their tenacity followed by ring- and rotor-spun yarns. The effective packing density of C/M blended yarn decreases with the increase in milkweed blend proportion due to less cohesiveness and poor self locking structure of fibres in the yarn cross-section

Thermal and sound insulation properties of chiengora blended nonwoven fabrics

A novel animal fibre chiengora has been explored for its potential application in textile. Chiengora fibres are made intononwoven fabrics by blending with polyester fibre in different proportions for their better strength. Nonwoven fabrics arealso produced from wool and polyester blends in different proportions for comparison. Hair of Lhasa Apso breed dog ischosen to blend with polyester to produce the nonwoven fabric and is analysed for its thermal and sound insulationcharacteristics. It is observed that 100% chiengora nonwoven fabric has thermal insulation value of 0.211 clo which is 42%higher than that of 100% wool nonwoven fabric (0.121 clo). The 70:30 chiengora/polyester fabric shows a thermalinsulation values of 0.141 clo which is higher than 100% wool nonwoven fabric. The chiengora nonwoven fabrics alsopossess similar sound insulation properties like wool [noise reduction coefficient value (NRC) of 0.23 for chiengora and0.22 for wool]. The increase in the chiengora and wool content in the blends reduces the tensile strength, tear strength andair permeability of the nonwoven fabrics. It is concluded that the chiengora blended nonwoven fabrics could be used as aneffective padding material because of their better thermal insulation and sound absorption properties

Multifarious transparent glass nanocrystal composites

Glasses comprising well known ferroelectric crystalline phases have been a subject of curious investigation from the point of view of exploiting these composites for dielectric, pyroelectric, ferroelectric, electro and non-linear optical devices. Transparent glass-ceramics containing ferroelectric crystallites at nano scale have been of much interest owing to their promising physical properties. The advantages that are associated with glass-ceramics include very low levels of porosity and hence high break down voltages. It is of our interest to nanocrystallize Aurivillius family of ferroelectric oxides and tetragonal tungsten bronzes on borate and tellurite based glass matrices and demonstrate their promising optical and nonlinear optical properties. Apart from the above, the nanocrystallites of well known ferroelectric material LiNbO3 was grown in a reactive glass matrix. These nanocrystals of LiNbO3 exhibited intense second harmonic signals in transmission mode when exposed to IR light at 1064 nm. The most interesting result was the demonstration of optical diffraction of the second harmonic signals which was attributed to the presence of self- organized sub-micrometer sized LiNbO3 crystallites that were indeed inscribed by the IR laser light which was used to probe in the NLO property of these materials

Comfort properties and dyeing behaviour of cotton/milkweed blended rotor yarn fabrics

Milkweed (M) fibres have been blended with cotton (C) fibres at three different proportions and the rotor-spun yarn fabrics are produced. The comfort properties of 100% cotton and C/M blended fabrics are analysed. The fabrics have been dyed with two types of reactive dyes, namely CI Reactive Yellow 3RS and CI Reactive Red 120, and the colour strength and other calorimetric parameters of the dyeing are analysed. From the comfort properties of the fabrics, it is noticed that the air and water vapour permeabilities of C/M blended fabrics are lower than the 100% cotton fabric and decrease with the increase in milkweed proportion. The thermal conductivity of C/M blended fabrics is lower than 100% cotton fabric and decreases with the increase in milkweed proportion. The reduction in inter-yarn space and higher yarn hairiness leads to reduction in air, water and thermal conductivity values with the increase in milkweed proportion. The wickability of C/M blended fabrics increases with milkweed proportion due to the open yarn structure and hollowness of milkweed fibres. From the dyeing behaviour of fibres, it is observed that the colour strength of C/M 80/20 is higher than 100% cotton and it decreases with the further increase in milkweed blend proportion. The low cellulose percentage, higher crystalline orientation index of milkweed fibres compared to cotton results in lower colour strength values with milkweed percentage greater than 20%

Effect of lateral crushing on tensile property of bamboo, modal and tencel fibres

The effect of lateral crushing on the tensile properties of bamboo, modal and tencel fibres has been investigated. A fibre crushing apparatus has been used for the purpose of lateral crushing of fibres. The influence of transverse compression on the axial mechanical properties of these fibres has been analysed. The study reveals that modal fibre sustained a higher loss in tensile properties compared to bamboo and tencel. The general phenomenon obtained from the study is that the percentage loss of strength and breaking extension varies from one fibre to another based on the fibre type and morphology

Comparative analysis of CRISPR off-target discovery tools following ex vivo editing of CD34+ hematopoietic stem and progenitor cells.

While a number of methods exist to investigate CRISPR off-target (OT) editing, few have been compared head-to-head in primary cells after clinically relevant editing processes. Therefore, we compared in silico tools (COSMID, CCTop, and Cas-OFFinder) and empirical methods (CHANGE-Seq, CIRCLE-Seq, DISCOVER-Seq, GUIDE-Seq, and SITE-Seq) after ex vivo hematopoietic stem and progenitor cell (HSPC) editing. We performed editing using 11 different gRNAs complexed with Cas9 protein (high-fidelity [HiFi] or wild-type versions), then performed targeted next-generation sequencing of nominated OT sites identified by in silico and empirical methods. We identified an average of less than one OT site per guide RNA (gRNA) and all OT sites generated using HiFi Cas9 and a 20-nt gRNA were identified by all OT detection methods with the exception of SITE-seq. This resulted in high sensitivity for the majority of OT nomination tools and COSMID, DISCOVER-Seq, and GUIDE-Seq attained the highest positive predictive value (PPV). We found that empirical methods did not identify OT sites that were not also identified by bioinformatic methods. This study supports that refined bioinformatic algorithms could be developed that maintain both high sensitivity and PPV, thereby enabling more efficient identification of potential OT sites without compromising a thorough examination for any given gRNA

Systematic in vitro specificity profiling reveals nicking defects in natural and engineered CRISPR–Cas9 variants

Cas9 is an RNA-guided endonuclease in the bacterial CRISPR–Cas immune system and a popular tool for genome editing. The commonly used Streptococcus pyogenes Cas9 (SpCas9) is relatively non-specific and prone to off-target genome editing. Other Cas9 orthologs and engineered variants of SpCas9 have been reported to be more specific. However, previous studies have focused on specificity of double-strand break (DSB) or indel formation, potentially overlooking alternative cleavage activities of these Cas9 variants. In this study, we employed in vitro cleavage assays of target libraries coupled with high-throughput sequencing to systematically compare cleavage activities and specificities of two natural Cas9 variants (SpCas9 and Staphylococcus aureus Cas9) and three engineered SpCas9 variants (SpCas9 HF1, HypaCas9 and HiFi Cas9). We observed that all Cas9s tested could cleave target sequences with up to five mismatches. However, the rate of cleavage of both on-target and off-target sequences varied based on target sequence and Cas9 variant. In addition, SaCas9 and engineered SpCas9 variants nick targets with multiple mismatches but have a defect in generating a DSB, while SpCas9 creates DSBs at these targets. Overall, these differences in cleavage rates and DSB formation may contribute to varied specificities observed in genome editing studies