Search

Eva Obodo's recent art exhibition at the kó gallery in Lagos showcased his works in textile art, which explore various aspects of social life in Nigeria. Obodo, a contemporary Nigerian artist and sculptor, incorporates techniques such as tying, stretching, and twisting materials to create extraordinary pieces. His works address social and political issues in postcolonial Africa, using materials like jute, fabric, and charcoal. The exhibition reflects the artist's sensitivity to the socio-political climate in Nigeria, particularly during the COVID-19 pandemic. Obodo's works challenge viewers to reflect on leadership challenges and the need for credibility, competence, and courage in society. [Extracted from the article]

Yarn engineering is a long-standing problem for the cotton spinning industry as the functional relationship between fiber and yarn properties is quite complex. The objective of this research is to develop a hybrid machine learning-based prescriptive yarn engineering system that can foretell the properties of cotton fiber for achieving desired yarn properties. Artificial neural network (ANN) and genetic algorithm (GA) were used to develop the predictive model for cotton yarn properties and optimization of cotton fiber properties, respectively. Two separate ANN models were developed for predicting yarn tenacity and yarn unevenness. The functional relationships approximated by the ANN models were used to formulate the fitness function for GA. The validation of the ANN-GA system demonstrated good accuracy as cotton fiber strength, length and length uniformity were predicted with very good accuracy (mean error < 5%). The developed machine learning system can supplant the intuition-based decision making in textile spinning industry and pave the way for yarn engineering. [ABSTRACT FROM AUTHOR]

Keywords: Spinning waste; cotton fibers; web; nonwoven; tear strength; burst strength; ; ; ; ; ; EN Spinning waste cotton fibers web nonwoven tear strength burst strength ZH 9064 9073 10 11/21/22 20221220 NES 221220 Introduction The raw material is considered as one of the most important factors affecting product costs in the textile industry based on its type, processing, and end-use. In this work, the webs of cotton fibers from spinning soft and hard wastes were formed after separating the short fibers from impurities by trash analyzer and carding fibers to form a web. Thus, textile material wastes can be classified as pre-consumer textile waste (soft and hard waste) and post-consumer textile waste. Following the procedures of staple length measurement mentioned above, the mean of fibers length from spinning waste is; I Mean fibers length (cm) = 1.34 ± 0.53 i The standard classification indicates that those fibers with length of 1 in. or less are categorized under short-staple fibers (Klein [11]). [Extracted from the article]

This paper reported the process of extraction and characterization of the properties of natural fiber from the leaves of the Furcraea foetida plant. The water retting method was used to extract the fiber. The fiber properties obtained were used to analyze the ability of fiber to be spun into yarn for textile application. A bundle of Furcraea foetida fibers consist of many individual fibers. The longitudinal view of the fiber cells show up as long cylindrical tubes and the cross-section of fibers were an irregular, polygonal shape. The tensile strength of the Furcraea foetida fibers was 3 g/denier. The elongation at break of the Furcraea foetida fibers was 8.61%. The fineness of the Furcraea foetida fibers was 8.3 tex. The average fiber length was 70.8 cm. The Furcraea foetida fibers were hygroscopic fibers with 8.48% moisture regain. The coefficient of friction of the Furcraea Foetida fibers was 0.053. The properties of the fiber showed that the Furcraea foetida fiber has potential to be spun into yarn. Natural fibers from the leaves of the Furcraea foetida plant could be used as an alternative material for textile application. [ABSTRACT FROM AUTHOR]

Disposal of large volumes of textile waste is an escalating problem for textile industries. Sisal spinning industry is the one of the textile industries releasing large volumes of textile waste in the landfills. The rising costs, and reduction of available space together with increasing stringent environmental measures are making burying and land filling of textile waste, a declining option. This study therefore explores recycling options where the potential of using sisal fiber waste produced during sisal spinning processes as raw materials for the production of paper pulp was investigated. Sampling was done at 21stCentury Holdings Limited allocated at Chang'ombe industrial street Dar es Salaam mainly dealer of sisal yarns production. Materials were prepared and cut into small pieces of about ½ inches to reduce the fiber into unit lengths so as to achieve pulping required performance. Pulping process was achieved through Soda pulping techniques with two different effective alkali charges (EA-20% and EA-24%) for 240 minutes under maximum temperature 140°C, and liquor to fiber ratio 4:1by using Mathis Labomat dyeing Machine. The kappa number obtained was (25.5, 34.5) for material treated under EA 24% and EA 20% respectively, Percentage pulp yield were (47.1, 54.4) for EA 24% and EA20% pulp respectively. Freeness (630CFS, 555CSF) after refining at 4500 rpm. Finally, the resulting pulp was used for hand sheet making and the sheets were tested for their mechanical properties; Grammage (61.1, 61.1) g/m2, Tensile index (9.9, 22.3) Nm/g, Tear index (13.3, 17.4) Nm2/g, burst index (1.7, 3.7 and 1.6) kPa.m2/g and Elongation at break (2.02, 2.22) % for EA24% pulp, EA20% pulp respectively. The findings shows that sisal fiber wastes have a promising potential for paper pulp production compared to other non-wood raw material. [ABSTRACT FROM AUTHOR]

Automation and mass-production are two of the many limitations in the tissue engineering industry. Textile fabrication methods such as electrospinning are used extensively in this field because of the resemblance of the extracellular matrix to the fiber structure. However, electrospinning has many limitations, including the ability to mass-produce, automate, and reproduce products. For this reason, this study evaluates the potential use of a traditional textile method such as spinning. Apart from mass production, these methods are also easy, efficient, and cost-effective. This study uses bovine-derived collagen fibers to create yarns using the traditional ring spinning method. The collagen yarns are proven to be biocompatible. Enzymatic biodegradability was also confirmed for its potential use in vivo. The results of this study prove the safety and efficacy of the material and the fabrication method. The material encourages higher cell proliferation and migration compared to tissue culture-treated plastic plates. The process is not only simple but is also streamlined and replicable, resulting in standardized products that can be reproduced. [ABSTRACT FROM AUTHOR]

The linear Doppler shift used for the detection of a spinning object becomes significantly weakened when the line of sight (LOS) is perpendicular to the object, which will result in the failure of detection. In this paper, a new detection and imaging technique for spinning objects is developed. The rotational Doppler phenomenon is observed by using the microwave carrying orbital angular momentum (OAM). To converge the radiation energy on the area where objects might exist, the generation method of OAM beams is proposed based on the frequency diversity principle, and the imaging model is derived accordingly. The detection method of the rotational Doppler shift and the imaging approach of the azimuthal profiles are proposed, which are verified by proof-of-concept experiments. Simulation and experimental results demonstrate that OAM beams can still be used to obtain the azimuthal profiles of spinning objects even when the LOS is perpendicular to the object. This work remedies the insufficiency in existing microwave sensing technology and offers a new solution to the object identification problem. [ABSTRACT FROM AUTHOR]

The article discusses the significance of African textiles as interconnected elements that embody various aspects of creation, including cultivation, spinning, dyeing, and weaving. It highlights the role of textiles in connecting people and places, with a focus on their materiality, design, cultural meaning, and documentation of changing trend. It also mentions different types of textiles, weaving techniques, and their cultural significance.

Modeling of the elastic properties of twisted polyester textile threads was studied. A decrease of the degree of twisting of the textile threads in the allowed limits shortened the time of the technological process and improved the economics. [ABSTRACT FROM AUTHOR]

In this study, a three‐dimensional (3D) electrospinning machine is designed and implemented as a new type of delta 3D printer that incorporates the fabrication of textiles directly into the 3D printing process. The newly designed 3D machine enables custom‐shaped electrospun nanofibre sheets to be fabricated in a single process. The implemented prototype allows controllable nozzle movements in 3D space. Four design patterns are successfully fabricated using a polyvinylidene fluoride (PVDF) solution at an 18% weight concentration. The microscopic properties of the electrospun patterns are verified via scanning electron microscopy (SEM) to investigate the fibre morphology. The SEM image at 14.5 kV shows that the PVDF electrospun nanofibres appear smooth and uniform with varying diameters in the range of 700–400 nm. [ABSTRACT FROM AUTHOR]

Spider silk spidroins consist of long repetitive protein strands, flanked by globular terminal domains. The globular domains are often omitted in recombinant spidroins, but are thought to be essential for the spiders' natural spinning process. Mimicking this spinning process could be an essential step towards producing strong synthetic spider silk. Here we describe the production of a range of mini-spidroins with both terminal domains, and characterize their response to a number of biomimetic spinning triggers. Our results suggest that mini-spidroins which are able to form protein micelles due to the addition of both terminal domains exhibit shear-thinning, a property which native spidroins also show. Furthermore, our data also suggest that a pH drop alone is insufficient to trigger assembly in a wet-spinning process, and must be combined with salting-out for effective fiber formation. With these insights, we applied these assembly triggers for relatively biomimetic wet spinning. This work adds to the foundation of literature for developing improved biomimetic spinning techniques, which ought to result in synthetic silk that more closely approximates the unique properties of native spider silk. [ABSTRACT FROM AUTHOR]

Improvements in multifunctional materials have led researchers to reinvigorate traditional textile structures by integrating emerging material technologies to offer novel solutions to diverse industries. However, there exist few multifunctional materials capable of being produced with micrometer diameters that can be spun into yarns for textile manufacturing, limiting the wearability and tunability of multifunctional textiles. Here, the creation of nickel‐titanium (NiTi) smart material‐based yarns is enabled by the availability of small diameter (≤10 µm) NiTi filaments that can survive the yarn spinning manufacturing process. NiTi microfilament yarns exhibit traditional superelastic and shape memory properties, and afford additional improvements to mechanical performance such as a tunable structural stiffness, plateau strength, and actuation contractions through the introduction of controllable geometric parameters—yarn count, surface twist angle, and manufacturing strains. This work concludes in a densely knitted, closed‐form textile with shape memory actuation and superelastic recovery. NiTi microfilament yarns and textiles have promising impacts in actuating and energy‐absorbing technologies for medical, robotics, aerospace, and defense applications. [ABSTRACT FROM AUTHOR]

In this report, a study of the wear mechanisms involved in the spinning ring and the traveler of textile industry are presented. These components, after surface processing with various coatings techniques, were analyzed on the test rig so as to analyze the wear mechanism. The objective was accomplished by comparing various plasma sprayed coatings on E52100 steel pins using a pin-on-disc machine. The surface morphology as well as mechanical properties of the deposited coatings, namely WC-Co- Cr, Al2O3+TiO2 (Alumina-Titania) and Cr3C2NiCr, as well as uncoated E52100, were comparatively studied. This study elucidates towards improving the working life of the ring in a textile mill in the spinning operation. An x-ray diffractometer (XRD) and scanning electron microscope (SEM) were employed to characterize the unworn and worn surfaces of the specimens. The study revealed that the wear rate of plasma sprayed thermal coatings enhanced with augmenting load. The plasma sprayed WC-Co-Cr, Cr3C2NiCr, Al2O3+13TiO2 coatings developed on workpiece pins exhibited a notable decrease in volume loss of the material as compared to uncoated E52100 substrate. WCCo- Cr coating turned out to be the best performer in terms of the lowest cumulative volume loss among all the variants of coatings. [ABSTRACT FROM AUTHOR]

The article focuses on the coverage of the subject of textile craft in the pages of the British journal "Textile History." Topics include a definition of craft, how the authors of the journal had engaged craft knowledge and utilized expertise to enhance their research on the subject, and an overview of an article on the origins of spinning that appeared in the periodical.

Spider silk fibers have remarkable mechanical properties as a result of an ultraoptimized spinning process. Silk fibers are spun from a lyotropic nematic liquid crystalline anisotropic fluid phase which undergoes significant structural changes throughout the spinning pathway. In the silk extrusion duct, those structural changes are expected to be driven by elastic-mediated interactions between point defects. In this work, the interaction between two point defects of opposite topological charges located on the axis of a cylindrical cavity is studied using a tensor order parameter formalism. Distinct regimes leading to defect annihilation and structural transitions are described in detail. The driving force setting the defects into motion is also examined. The different results suggest that the tensorial approach is primordial in describing the complicated physics of the problem. The phenomenon described is important to the understanding of the process-induced structuring of silk fibers and to defect physics in a more general context. [ABSTRACT FROM AUTHOR]

Abstract Different colored fibers were blended into yarns by digital rotor spinning to meet the market demand of multi-species and small-batch production. In order to study the color blending effect of spun yarn, two-component and three-component blended yarns were obtained by red, yellow and blue slivers, and woven as fabrics. Parameters of K-M double constant theoretical model were calculated by the color characteristics of fabrics. The absorption coefficient (K) and the scattering coefficient (S) of the monochromatic fiber were calculated by the method of least squares and the method of relative value, respectively. According to the above methods, two Kubelka-Munk double constant color blending models were built. The two models were used to predict colors and blending ratios of fabrics. The results show that the K-M model established by the least squares method can better predict color blending effect and the blending ratio of digital rotor spun yarn. Highlights • A smart and sustainable spinning for colorful textiles was introduced. • K-M model of digital rotor spun yarn were built by the relative value method and the least squares method respectively. • The blended fabric color and blending ratio were calculated and predicted. • Compared with relative value method, K-M model built by least squares method can better predict the color blending effect. [ABSTRACT FROM AUTHOR]

The use of textile-grade fiber extracted from the Indian pineapple leaf is an unexplored area. Pineapple leaf fiber (PALF) is fine, soft, and moderately strong and is much acceptable for fashion garment. An attempt has been made to extract and soften Indian PALF from the pineapple leaves by decortication and subsequent water retting. Decorticated cum retted fiber has shown better physicomechanical and surface appearance properties than decorticated fiber. Fine yarn (38 tex) was spun in a suitable spinning system, and the property performance was found to be suitable to make eco-sustainable novelty fabric. Fabric was developed by using cotton as warp yarn and PALF-based yarn as weft in a handloom. The developed fabric shows very good physical and mechanical properties, desired for apparels. This inferred that Indian PALF may be successfully used to make eco-niche apparel quality fabric as well as novelty textiles. [ABSTRACT FROM AUTHOR]

Abstract Activated microporous polyacrylonitrile-based carbon nanofibers (APCFs) were synthesized by a sequential process of electrospinning, carbonization, and KOH activation. The porosity and surface chemistry of the APCFs strongly depended on the activation temperature. The specific surface area and pore volume varied from 15 to 1886 m2 g−1 and 0.021–1.196 cm3 g−1, respectively, as the activation temperature increased; this was accompanied by morphology changes at high temperature. The dominant microstructure and minor mesostructure improved the capacitance of carbon. Compared to the other samples, APCFs activated at an optimum temperature of 1000 °C showed the highest specific capacitance of 103.01 F g−1 at 1 A g−1 in 1 mol L−1 Na 2 SO 4 aqueous electrolyte, and an excellent cycling durability up to 3000 cycles. The improved electrochemical efficiency could be explained by the high specific surface area, suitable pore size, and influence of heteroatoms relative to the increased electrical double-layers. The change in the pore size distribution with activation temperature is also discussed in detail. [ABSTRACT FROM AUTHOR]

Abstract Flange wrinkling is one of the common defects that occur in conventional spinning process, severely restricting the improvement of forming quality and formability. How to universally determine the formability dependent on flange wrinkling is a critical issue in conventional spinning process. For this end, such a determining method for the formability in the process is proposed to rationally design the forming parameters to prevent flange wrinkling. The method is as follows: firstly, the maximum circumferential stress during the process is calculated at the outer edge of the flange, where the circumferential stress is considered as the combining result of the shrinkage of flange diameter and the bending of flange; then, the formability is determined by comparing the maximum circumferential stress to critical circumferential stress for wrinkling defect. Based on the method, a formability analytical model considering wrinkling defect in the first-pass conventional spinning process with a linear roller path is established. The formability model is validated by experiments and FE simulations at different spinning conditions. Sequentially, the influences of forming parameters and their interaction on the formability considering wrinkling defect are systematically analyzed. Furthermore, the forming diagrams considering wrinkling defect for the first-pass conventional spinning are established. It is found that the feed ratio has the most significant effect on the formability, followed by the blank thickness, the hardening exponent, the feed ratio-hardening exponent interaction and the feed ratio-sheet blank thickness interaction. The smaller feed ratio and hardening exponent, thicker sheet blank and greater relative sheet blank radius are helpful to increase the formability. The research results could provide a theoretical basis and guidance for the selection of forming parameters in the actual production of the first-pass conventional spinning. [ABSTRACT FROM AUTHOR]

Highlights • The remarkable biomedical applications of chitosan are discussed. • The electrospinning process for chitosan and a chitosan blend are reported. • The application of films and membranes of chitosan for wound dressings is described. • In vivo, in vitro studies and drug delivery applications of chitosan are reviewed. Abstract This review outlines new developments in the biomedical applications of environmentally friendly ('green') chitosan and chitosan-blend electrospun nanofibers. In recent years, research in functionalized nanofibers has contributed to the development of new drug delivery systems and improved scaffolds for regenerative medicine, which is currently one of the most rapidly growing fields in all of the life sciences. Chitosan is a biopolymer with non-toxic, antibacterial, biodegradable and biocompatible properties. Due to these properties, they are widely applied for biomedical applications such as drug delivery, tissue engineering scaffolds, wound dressings, and antibacterial coatings. Electrospinning is a novel technique for chitosan nanofiber fabrication. These nanofibers can be used in unique applications in biomedical fields due to their high surface area and porosity. The present work reviews recent reports on the biomedical applications of chitosan-based nanofibers in detail. [ABSTRACT FROM AUTHOR]

Abstract ZnO/In 2 O 3 composite nanofibers were fabricated by electrospinning method and effects of process parameters on the distribution and mean diameter of synthesized NFs were investigated. Electrospinning process followed by post calcination was performed at two different temperatures to optimize the synthesis condition of ZnO and In 2 O 3 NFs. Thermal Analysis was done on electrospun fibrocomposites to find calcination temperatures. Electrospinning parameters (Tip to Collector Distance (TCD), feeding rate, and applied voltage), which led to a uniform distribution and thinnest NFs, were used for synthesizing ZnO/In 2 O 3 composite in the co-electrospinning process. Structural, morphological, and chemical studies were also carried out on the NFs. TCD increment led to the improvement of diameter distribution and homogeneity of synthesized NFs. Low voltages (below 20 kV) resulted in thinner fibers without appearing any remarkable beads defect and the optimum feeding rate was found to be 1 ml/h. For further application of NFs in gas sensors, well distributed thinnest fibers were obtained. [ABSTRACT FROM AUTHOR]

A three-dimensional (3D) image reconstruction method for the spinning target based on the radar network is proposed in this letter and the design concept is sourced from the similarity of the two-dimensional (2D) imaging result with the target’s mapping on the imaging plane. The proposed method has the capacity to generate 3D image of the spinning target by reconstructing the scattering distribution in 3D Cartesian space. Firstly, the inverse Radon transform is applied to obtain the imaging result of the spinning target and the mapping formulas for mapping the air points onto the 2D image plane are derived. In addition, the radar network 3D image reconstruction model for the spinning target is constructed and the corresponding algorithm for solving the reconstruction model is proposed. Finally, some experiment results are given to verify the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Highlights • The electrospinning was developed for fabrication of collagen mimetic scaffold. • With addition of LA, LA assisted formation of 3D cotton-like fibrous structure. • The physicochemical properties of the as-fabricated scaffold were evaluated. Abstract The ability to mimic the topography of aligned collagen fiber bundles (A-CFB) that form the structural basis for the extracellular matrix (ECM) can be an important step in the fabrication of engineered scaffolds. Because the cell adhesion to the surface topography involve cell adhesion localized structures, topographical features, which mimics the A-CFB of the matrix can be a significant factor for cell activities. In this study, we present a novel method for the fabrication of low-density electrospun fibers mimicking A-CFB constructs. The three dimensional (3D) cotton-like A-CFB mimetic scaffold (3D-CACMS) of a mixture of lactic acid (LA) and polycaprolactone (PCL) was prepared by multiple pins rotator electrospinning (MPRES), followed by selective leaching of LA. The results of SEM, FTIR, TGA, and DSC revealed the physicochemical properties of the as-fabricated scaffold. This 3D-CACMS attempt to mimic A-CFB and can potentially meet the requirements for practical use of biomedical engineering. [ABSTRACT FROM AUTHOR]

Cylinder shell parts are widely used in industrial and civil areas, and 304 stainless steel cylinders were attempted to be formed by multi-pass drawing spinning. But wrinkling failure occurs in the spinning process. In order to suppress it, two comparative experiments with 206 mm and 245 mm mandrel diameters are carried out to reveal the wrinkling mechanism of multi-pass drawing spinning of 304 stainless steel cylinders. It is found that a thicker mandrel diameter is conducive to the wrinkle suppressing due to the larger instantaneous contacting zone caused by the bigger mandrel. The restraining mechanism of the wrinkling failure is due to the fact that a larger contacting zone can accommodate more circumferentially squeezed metal resulting in smaller tangential compressive stress. This is further proved by the spinning experiment with roller path amendment. The roller path is amended by increasing the curvature of the roller path arc and removing the backward arcs to reduce the tangential compressive stress. Almost no wrinkling failure occurs in the new 304 stainless steel cylinder spinning process. [ABSTRACT FROM AUTHOR]

The article focuses on the earliest German Redaction of the Christian book "Legatus divinae pietatis." Topics discussed include the meditating role of the Carthusians in promoting the Legatus; the Carthusian's mission as translators of theological and spiritual texts into the vernacular; and textile culture, in which spinning and sewing were considered devotional works that stimulated contemplation.

An organosoluble copolyimide (co-PI) was synthesized from 3,3′,4,4′-benzophenonetetracarboxylic dianhydride (BTDA), 1,4-bis-(4-aimino-2-triflupromethyl-phenoxy)-benzene (p-6FAPB), and 2-(4-aminophenyl)-5-aminobenzimidazole (BIA) via the one-step polymerization using N-methyl-2-pyrrolidone (NMP) as the solvent, and high-performance co-PI fibers were directly prepared by the dry-spinning process on a large scale. Scanning electron microscopic images show that all formulations of as-spun fibers exhibit elliptical cross sections as well as dense morphologies. The structural evolution of the co-PI fiber induced by the high rolling speed and post-heat-drawing treatment was studied by means of thermogravimetric analysis, dynamic thermomechanical analysis, and two-dimensional wide-angle X-ray diffraction (2D WAXD). With increasing rolling speeds, glass transition temperatures (Tgs) and thermal stabilities of as-spun fibers slightly decrease, which may be resulted from the disentanglement of entangled molecular chains under the large deformation and high-temperature heating atmosphere in the spinning column. 2D WAXD data indicate that both increasing rolling speeds and post-heat-drawing treatment are beneficial for getting a highly ordered structure along the meridian direction of the fibers. The fibers treated at 430°C exhibit outstanding mechanical properties, and the tensile strength and modulus reach 1.44 GPa and 48.69 GPa, respectively, at a drawing ratio of 2.8. [ABSTRACT FROM AUTHOR]

Abstract Nowadays, aloe-vera (AV) is exploited extensively in nanofibrous structures for skin substitutes. However, the lack of electrospinnability and appropriate mechanical characteristics are the key limitations for this natural extract to be used in the form of nanofibrous mats. In this study, two commercially available biopolymers, gelatin (Gel) and poly(ε‑caprolactone) (PCL), were chosen to improve these issues and double-nozzle electrospinning technique was used to fabricate hybrid scaffold from Gel/AV blend and PCL solutions. Response surface methodology was utilized to investigate the effect of electrospinning parameters (Gelatin concentration, Aloe-vera concentration and Gel/AV feed-rate) on the mechanical properties, morphology and hydrophilicity of nanofibers and the optimized scaffold was chosen for further studies. In order to verify the application of this scaffold in bioapplications, the chemical, thermal and biological features of scaffold were analyzed using FTIR, DSC, biodegradability, bactericidal, biocompatibility and drug-delivery. The results revealed that the presence of aloe-vera improved the antibacterial activity (>99% and 85.63% against Gram-positive and Gram-negative bacteria, respectively), and led to adequate in-vitro biodegradation. Furthermore, it was found that incorporation of aloe-vera increased the cell viability without any toxicity. Graphical abstract Unlabelled Image Highlights • Aloe vera extract was produced successfully without any change in chemical and biological nature. • Aloe vera nanofibers were produced using double nozzle electrospinning. • MTT assay shows that fabricated scaffold doesn't have any toxicity. • FESEM images of cell cultured scaffold states that cells can proliferate on this biomaterial. • Tests show higher antibacterial activity for gram positive and gram negative bacterias. [ABSTRACT FROM AUTHOR]

Mass fabrication of sodium alginate nanofibers using single-nuzzle electrospinning process is an open challenge mainly due to its inter- and intramolecular hydrogen bonding, rigid chain conformation and low solubility. In this regards, we synthesized sodium sulfated alginate (SSA) through sulfation of hydroxyl functional groups of alginate. Not only decreases the hydrogen bonding density through the sulfation reaction, but the sulfated alginate also demonstrates more solubility in aqueous media compared to the pristine alginate. Beside the sulfation of alginate, its electrospinnability in combination with polyvinyl alcohol (PVA) significantly improves. In contrast to the neat alginate, concentrated aqueous solutions of sulfated alginate, 10 wt%, can be easily prepared and electrospun to obtain nanofibers of sulfated alginate. In this regards, facile fabrication of electrospun nanofibers of alginate derivatives with 50 wt% content in dry electrospun mat of SSA/PVA using single-nuzzle electrospinning and flow rate of 5 mL h −1 was developed for the first time. [ABSTRACT FROM AUTHOR]

Based on exploitation values of reliability, which express approximate values of work reliability of integral parts of analyzed circuit with maximal security for their more precise assessment a determination of their correctional values is used. This is made for a goal in order to determine total transmission function of work reliability of parts of analyzed circuit to get the most accurate values of reliability. Based on designed diagrams of dependability on reliability of exploitation operational time of every integral component of analyzed circuit in case of selected statistical distribution, the areas of exploitation work and repair intervals are determined. In this way it is possible to implement the technology for preventive maintenance of integral parts of the circuit and their proper repairs. [ABSTRACT FROM AUTHOR]

Traditionally, the carrageenan fibers were prepared by process of extracting, drying, dissolving of carrageenan power and wet spinning process of fibers. However, in this study, carrageenan fibers were prepared by carrageenan solution directly from the extraction of Chondrus , without the steps of precipitation, and drying. The properties of carrageenan powder, spinning solution and carrageenan fibers were characterized with zeta potential, NMR, FTIR, dynamic light scattering (DLS), SEM, tensile testing and energy dispersive spectrometer (EDS). The results showed that the Chondrus contained mainly iota-carrageenan. The extraction of Chondrus was a uniform liquid with good properties of a solution, which was suitable as a spinning solution. The so prepared carrageenan fibers possessed good morphology and tensile properties. The excellent tensile properties of the carrageenan fibers were attributed to the combination of sulfate ester in the carrageenan and barium ions in the coagulation and then form a three-dimensional network structure. [ABSTRACT FROM AUTHOR]

Ultrathin sectioning and solvent etching were used to assess microstructural changes in polyacrylonitrile (PAN) fibrils following a dry-jet wet spinning process. Morphologic assessment revealed the coexistence of fibrils and lamellae within the PAN fibers, with a frill-like structure found on the fibrils. The size of the lamella-like layers was consistent with a crystal size of 13.2 nm as characterized by X-ray diffraction and microfibrils were composed of alternate dark lamella-like crystal layers and surrounded by bright amorphous chains. Further, fibril arrangement followed a weave-like pattern. During the post-spinning process, break-rearrangement of chain-folded lamellae had an important role in fibril structure evolution. The high stream stretching and heat treatment induced the breaking of lamellae and the formation of new lamellae through the molecular chains rotating and slipping, resulting in a decrease in voids and the coalescence of microfibrils. Consequently, the fibrils were arranged in a more orderly manner and interlinked more tightly, a process conducive for the preparation of high quality PAN fibers. [ABSTRACT FROM AUTHOR]

We demonstrate that in solid-state nuclear magnetic resonance the Hartmann–Hahn cross-polarization efficiency in the presence of fast magic angle sample spinning can be improved by the application of rotor-synchronized amplitude-modulated radio-frequency irradiation during the mixing time (AMCP pulse sequences). The modulation reintroduces time-independent coupling elements between dressed eigenstates of the Floquet Hamiltonian which lead to flip–flop transitions. By numerical optimization, an optimal AMCP pulse sequence is designed which provides a significant improvement over conventional cross polarization. The matching condition can be broadened by rotor-synchronized 180° phase shifts to render the transfer less sensitive to exact matching of the applied radio-frequency field strengths. © 1995 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Isotropic Nd-Fe-B nanocrystalline fine powders with particle size in the range of 1-10 μm have been developed using melt spinning and jet milling. The processing steps primarily consist of melt spinning Nd-Fe-B alloy to obtain ribbons with 25-50 μm thickness, crushing the ribbon to obtain coarse powder with average particle size of about 200 μm, and jet milling the coarse powder to obtain fine powder with average particle size of about 5-6 μm. The effects of jet milling conditions on powder particle size, microstructure, and magnetic properties were systematically studied. For a magnet alloy nominally composed of Nd11.9μ(Fe0.93Co0.07)82.6B5.5, a particulate yield of D10 =2 μm, D50=6 μm, and D90=11 μm and magnetic properties of Br=8.82 kG, Hci=9.5 kOe, and μ(BH)max=15.3 MGOe have been achieved in melt-spun and jet milled fine powders. The combined advantage of small particle size and high magnetic performance will make the Nd-Fe-B fine powder an attractive candidate for applications such as magnetic fluids, inks, micromachines, and flexible sheets. [ABSTRACT FROM AUTHOR]

Magnetic properties, phase evolution, and microstructure of melt spun SmCo7-xHfxCy (x=0–0.5; y=0–0.14) ribbons via direct quenching have been investigated. For SmCo7-xHfx series ribbons, proper volume fraction of Hf is effective to stabilize and increase the magnetocrystalline anisotropy field of the TbCu7-type structure. Accordingly, the optimal magnetic properties of Br=6.4 kG, iHc=7.3 kOe, and (BH)max=8.7 MG Oe could be obtained for x=0.1. Furthermore, a slight C addition to above alloys is helpful in refining the grain size of the ribbons from 100–400 nm for C-free to 10–80 nm for C-containing samples. As a result, the magnetic properties are further improved to Br=6.9 kG, iHc=11.8 kOe, and (BH)max=10.6 MG Oe for SmCo6.8Hf0.2C0.12 nanocomposite ribbons. [ABSTRACT FROM AUTHOR]

The effect of the metal halide FeCl2 and its hydrate on increasing the intensity of corrosion-mechanical wear of the parts of gear metering pumps during the dosing of spinning solutions for spinning aramid fibers was studied. One of the ways to reduce the intensity of wear and, correspondingly, increase the life of metering pumps by manufacturing pumps of a new design with a casing made of a composite material with a polymer matrix is considered. [ABSTRACT FROM AUTHOR]

It is an important approach to prevent the damage mechanisms that cause sudden fractures during fatigue loading in bonding joints by modifying the matrix with nanostructured materials. The aim of this study is to examine the effect of graphene nanoplates (GNPs) doped nylon 66 (N66) nanofiber mats reinforcement on the fatigue life of composite to aluminum single lap joint. For this purpose, 1 wt%, 3 wt% and 5 wt% GNPs doped N66 nanofibers were produced by electrospinning method. The morphological characteristics, chemical bond structures and % crystallinity of these nanofiber mats was investigated by SEM, TEM, FTIR, DSC analysis. The fatigue tests of the bonding joints with single axis periodic cycle loading were performed at five different load levels as 20%, 30%, 40%, 50% and 60% of the maximum shear strength of each samples. Fatigue life of bonding joints was assessed by S-N curves plotted according to the fatigue results. Damage mechanisms of fractured surface in the bonding joints were investigated with the macro and micro images. The results show that, these composite nanofiber mats have increased the fatigue life of bonding joints in all case. [ABSTRACT FROM AUTHOR]

An artificial spinning system using regenerated silk fibroin solutions is adopted to produce high-performance silk fibers. In previous studies, alcohol-based agents, such as methanol or ethanol, were used to coagulate silk dope solutions, producing silk fiber with poor mechanical properties compared with those of native silk fibers. The alcohol-based coagulation agents induce rapid β-sheet crystallization of the silk molecules, which inhibits subsequent alignment of the β-sheet crystals. Here, we induce gradual β-sheet formation to afford adequate β-sheet alignment similar to that of native silk fiber. To this aim, we developed an amorphous silk fiber spinning process that prevents fast β-sheet formation in silk molecules by using tetrahydrofuran (THF) as a coagulation solvent. In addition, we apply postdrawing to the predominantly amorphous silk fibers to induce β-sheet formation and orientation. The resultant silk fibers showed a 2.5-fold higher extensibility, resulting in 1.5-fold tougher silk fibers compared with native Bombyx mori silk fiber. The amorphous silk fiber spinning process developed here will pave the way to the production of silk fibers with desired mechanical properties. [ABSTRACT FROM AUTHOR]

Abstract: Stearns‐Noechel model was utilized as a primary reference to study color matching principles of digital rotor spun yarn. Three primary colored (red, yellow and blue) cotton fibers were used to spin blended yarns. Spectral reflectance of the two‐component and three‐component samples was measured with data color spectrophotometer. For these samples, the Stearns‐Noechel model parameter M was determined. Four methods were employed to calculate the M value to improve accuracy of the model, 1.Classical method, named as M1; 2.Optimizing the M1 value obtained by the classical method considering the wavelength factor, named as M2; 3.Simplified M2 according to the linear correlation with the wavelength, named as M3; 4. Simplified M2 according to the segmentation correlation with the wavelength, named as M4. The study shows that average color difference of the two‐component decreases from 2.7 to 1.48, and for three‐component samples from 3.32 to 1.66, by using M2 instead of M1. While calculated using M3, the color difference of the two types of samples will be 1.73 and 2.19, correspondingly. This cannot meet color matching needs. As for M4, the average color difference of the two categories will be 1.54 and 1.91, better than the result obtained using M1 and M3, worse than M2. [ABSTRACT FROM AUTHOR]

The present study describes the fabrication of Tripolyphosphate (TPP)-crosslinked nanofibrous mats based on chitosan for use as a floating gastro-retentive delivery system. TPP-crosslinked chitosan (CH)/poly (ethylene oxide) (PEO)- ranitidine hydrochloride (RH) electrospun nanofibers (75.27 ± 2.10 nm) were prepared by electrospinning 70% v/v acetic acid solutions, and followed by crosslinking by TPP anions. The mechanical, structural and morphological properties of the prepared nanofibers were evaluated via tensile testing, XRD, FT-IR, TGA, NMR, AFM and SEM experimental techniques. The prepared nanofibrous mats showed a pH sensitive swelling profile with maximum water absorbing at pH 1.2. Results obtained from above experimental techniques indicated that crosslinking process did not significantly altered morphological property of nanofibers but rather decreased their diameter and swelling degree, and increased their mechanical properties, thermal stability and bioadhesive strength. Viscosity measurements showed that the addition of PEO and RH to the chitosan solution, depending to its concentration lead to decrease in the viscosity of its solution. Also, floating test showed that the prepared nanofibrous mats remain floated onto surface of the dissolution medium for more than 48 h. Based on in- vitro drug release data analysis, TPP-crosslinked CH/PEO nanofibrous mats decreased initial burst release and it was exhibited a sustained release profile for the RH from the TPP-crosslinked CH/PEO-RH electrospun nanofibrous mats. [ABSTRACT FROM AUTHOR]

Abstract: Polymeric fibers are prepared by using electric field driven fiber production technology—electrospinning and pressure driven fiber production technology—pressurized gyration. Fibers of four different polymers: polyvinylidene fluoride (PVDF), poly(methyl methacrylate (PMMA), poly(N‐isopropylacrylamide), and polyvinylpyridine (PVP), are spun by both techniques and differences are analyzed for their suitability as drug carriers. The diameters of electrospun fibers are larger in some cases (PVDF and PMMA), producing fibers with lower surface area. Pressurized gyration allows for a higher rate of fiber production. Additionally, drug‐loaded PVP fibers are prepared by using two poorly water‐soluble drugs (Amphotericin B and Itraconazole). In vitro dissolution studies show differences in release rate between the two types of fibers. Drug‐loaded gyrospun fibers release the drugs faster within 15 min compared to the drug‐loaded electrospun fibers. The findings suggest pressurized gyration is a promising and scalable approach to rapid fiber production for drug delivery when compared to electrospinning. [ABSTRACT FROM AUTHOR]

In this study a thermo-sensitive switching membrane was prepared through grafting, using a click reaction, of an N -isopropylacrylamide (NIPAAm) derivative onto an electrospun poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) fibrous membrane (EPFM). The PPO was first electrospun into a fibrous membrane, then brominated and reacted with NaN 3 to generate the azido-terminated EPFMs. A propargyl-terminated poly( N -isopropylacrylamide) (PNIPAAm) was synthesized and grafted onto the azido-terminated EPFMs. The surface roughness of PPO fibers was increased due to the presence of PNIPAAm grafts, such that the thermoresponse of the static water contact angle (SWCA) of PNIPAAm-grafted EPFMs between 25 and 45 °C was significantly greater than that of the same PNIPAAm grafted on a flat surface. Thermo-sensitive affinity of the membrane with water resulted the average pore dimension responded to temperature changes. Taking advantage of this temperature-responsive affinity, we applied the membranes as protein valves that blocked and released an antibody. At 25 °C, the collection efficiency was 90% for antibody concentrations of up to 5 ng/mL. Increasing the temperature to 45 °C caused the collection efficiency to decrease abruptly, to 7.5%, when the antibody concentration was greater than 1.5 ng/mL. Accordingly, this system of PNIPAAm-grafted PPO fibers functioned as a protein valve, allowing the blocking and release of proteins. [ABSTRACT FROM AUTHOR]

The electrospun polyvinylidene fluoride (PVDF) based modified boron nitride (m-BN) composite with high thermal conductivity and flexible mechanical property was successfully fabricated by electrospinning method. The uniform dispersion and ordered orientation of m-BN in the m-BN/PVDF composites form a hot string, denoted as a series of thermal conduction fillers, in the direction of the fiber. Hence, the thermal conductivity of the m-BN/PVDF film could reach to 7.29 W m −1 K −1 with the addition of 30 wt% m-BN. Besides, the obtained composites also show improved mechanical properties with the tensile strength of 24.06 MPa, low dielectric permittivity of 2.45 and dielectric loss of 0.0242 @ 10 3 Hz. Therefore, this work provides a new route to prepare the high thermal conductivity films with potential application as flexible power devices. [ABSTRACT FROM AUTHOR]

In this study, a syringe pump was designed and built to determine the effect of the physical properties of the spinning part of a machine and the physical properties of the wet spinning process. Through the wet spinning method and fuzzy separation process, solid fibers were produced under experiments designed by the response surface method and statistical model of composite center design to predict the exact tensile strength. Polymeric fibers produced by atomic absorption spectrometry were used as adsorbent. This study aimed to evaluate the effects of spinning velocity, length-to-diameter ratio of the spinner, spinner diameter, and weight percentage of the polymer on the mechanical properties and structure of the sample. Scanning electron microscopy tests were conducted on the samples to analyze their structural properties, and the output pictures showed that the samples had a desirable microstructure. Analysis of variance indicated that the physical parameters of spinning produced the most significant effect on improving fiber properties. Results of data analysis showed that the length-to-diameter ratio and spinner diameter were the most effective process conditions that could be used to examine the data on tensile strength and optimum ratio of fiber diameter to spinner diameter. Finally, optimization was performed using the utility function to maximize the amount of tensile strength, and the process experimental results were evaluated. The results showed that the response surface models could adequately predict the values of the response variable. The gage R&R method was used to determine the amount of error due to the measurement system. [ABSTRACT FROM AUTHOR]