Soft Fibers Research Articles

Optimization of magnetic properties and hyperthermia study on soft magnetic nickel ferrite fiber

Nickel ferrite fiber (NFO–F) was synthesized using the electrospinning technique and annealed at five different temperatures (500, 600, 700, 800, and 900 °C) to study its effect on crystal structure and magnetic properties. The X-Ray diffraction pattern analysis was carried out to explore its crystal structure. The morphology and microstructure of fibers were studied by employing the Field Emission Scanning Electron Microscopy technique. The crystallinity of the material increases with the increase of annealing temperature from 500 to 900 °C. The saturation magnetization of nickel ferrite fiber increases from 31.1 to 54.0 emu/g with the increase in annealing temperature. The anisotropy constant for NFO–F calculated using the Law of Approach to Saturation (LA) and it shows the highest value for 900 °C annealed sample. Hence, the hyperthermia property of NFO–NF annealed at 900 °C has been explored. The Specific Absorption Rate (SAR) of NFO–NF calculated using Linear Response Theory and the Box-Lucas models.

An Ultrastretchable Electrical Switch Fiber with a Magnetic Liquid Metal Core for Remote Magnetic Actuation.

In this work we describe a soft and ultrastretchable fiber with a magnetic liquid metal (MLM) core for electrical switches used in remote magnetic actuation. MLM was prepared by removing the oxide layer on the liquid metal and subsequent mixing with magnetic iron particles. We used SEBS (poly[styrene-b-(ethylene-co-butylene)-b-styrene]) and silicone to prepare stretchable elastic fibers. Once hollow elastic fibers form, MLM was injected into the core of the fiber at ambient pressure. The fibers are soft (Young’s modulus of 1.6~4.4 MPa) and ultrastretchable (elongation at break of 600~5000%) while maintaining electrical conductivity and magnetic property due to the fluidic nature of the core. Magnetic strength of the fibers was characterized by measuring the maximum effective distance between the magnet and the fiber as a function of iron particle concentration in the MLM core and the polymeric shell. The MLM core facilitates the use of the fiber in electrical switches for remote magnetic actuation. This ultrastretchable and elastic fiber with MLM core can be used in soft robotics, and wearable and conformal electronics.

Effect of carbon fiber waste on steel corrosion of reinforced concrete structures exposed to the marine environment

This study experimentally investigates the possibility of using chopped carbon fiber waste for mitigating steel corrosion in reinforced concrete structures. Chopped carbon fiber waste was surface treated with epoxy to address the uniform dispersal of soft chopped carbon fiber into the cement mixture and prevent galvanic coupling between chopped carbon fiber and steel bars. The steel corrosion of reinforced concrete structures with different chopped carbon fiber percentages has been analyzed via electrochemical corrosion measurements, load-displacement curves and microscopy observation analysis. reinforced concrete beams were subjected to sustained point loading, a mass fraction of 3.5% Sodium Chloride marine wet-dry cycle and 50 °C environments for 360 days. A decrease in corrosion rate was observed in the beams with chopped carbon fiber waste compared to the control beams without chopped carbon fiber. The decreased corrosion rates in beams with 2.5% and 5% chopped carbon fiber (mass fraction of cement) were approximately 20% and 10%, respectively, compared to the beams without chopped carbon fiber. The ultimate strength of beams with 2.5% chopped carbon fiber and 5% chopped carbon fiber was increased by 25% and 17% compared to the control beams. Therefore, chopped carbon fiber waste could be used in reinforced concrete structures for reducing corrosion activity.

Mechanical Behavior of Concrete Reinforced with Waste Aluminium Strips

The main objective of this research work is to investigate the influence of the addition of waste materials, like aluminium waste material, Soft Drink Tin Fibers (SDTF) or soft tins to improve mechanical properties of concrete and also study the strength behavior of concrete, such as flexural strength and indirect or split tensile strength. It has been acknowledged that the use of fibers in concrete has considerable effects to improve strength parameters and characteristics of concrete. In this research work, similar efforts are made to present the effects of soft tin fibers or aluminium waste material as a reinforcing material in concrete and to assess the mechanical behavior of concrete. Particularly, this research work aimed to investigate experimentally the effect of soft drink tins on tensile (cylinder splitting tensile strength) and flexural strength. Soft tin fibers of 25.4 5 0.5 mm in size were used and added from 1 to 5% by the weight of cement with the design mix of 1:1.624:2.760 at 0.50 w/c ratio. Therefore, 6 batches (every batch contained 3 prisms and 3 cylinders) were prepared and cast for evaluation of tensile and flexural strength. One batch was cast without inclusion of fibers (controlled batch) and remaining 5 batches were cast with the addition of fibers using 1, 2, 3, 4, and 5% respectively. It was revealed from obtained results that split tensile strength and flexural strength of specimen increases as compared to controlled batch up to 4% addition of fibers. Moreover, beyond 4% soft drink tin fiber level, strength begins to fall down. Thus, it can be suggested that mechanical properties of concrete can be enhanced by 4% of soft drink tin fibers. Moreover, in this study, soft drink tin fibers (SDTF) or aluminium waste are used as the application of utilization of waste materials as a partial construction material and also on another side it controls the solid waste and environmental pollution. Doi: 10.28991/cej-2021-03091718 Full Text: PDF

Automated Assembly of Starch and Glycogen Polysaccharides

Polysaccharides are Nature’s most abundant biomaterials essential for plant cell wall construction and energy storage. Seemingly minor structural differences result in entirely different functions: cellulose, a β (1–4) linked glucose polymer, forms fibrils that can support large trees, while amylose, an α (1–4) linked glucose polymer forms soft hollow fibers used for energy storage. A detailed understanding of polysaccharide structures requires pure materials that cannot be isolated from natural sources. Automated Glycan Assembly provides quick access to trans-linked glycans analogues of cellulose, but the stereoselective installation of multiple cis-glycosidic linkages present in amylose has not been possible to date. Here, we identify thioglycoside building blocks with different protecting group patterns that, in concert with temperature and solvent control, achieve excellent stereoselectivity during the synthesis of linear and branched α-glucan polymers with up to 20 cis-glycosidic linkages. The molecules prepared with the new method will serve as probes to understand the biosynthesis and the structure of α-glucans.

Soft-fiber-reinforced tough and fatigue resistant hydrogels

Soft-fiber-reinforced tough and fatigue resistant hydrogels

ИННЕРВАЦИЯ КРОВЕНОСНЫХ СОСУДОВ ПОЧКИ У БЕЛОЙ ЛАБОРАТОРНОЙ КРЫСЫ

In the adventitia, there are mainly thick and medium-sized pulp fibers, the diameter of the thick nerve fibers is 0.3±0.2 mm. From the adventitia, nerve fibers penetrate into the muscle membrane, where the nerves have a large length, their diameter is 0.1±0.2 mm. There are quite a lot of soft nerve fibers lying in adventitia, in intima and media, with the presence of nuclei. The diameter of the thin nerve fibers is – 0.03±0.2 mm.

High Contrast All-Optical Dual Wavelength Switching of Femtosecond Pulses in Soft Glass Dual-Core Optical Fiber

All-optical switching of 75 fs pulses centered at 1560 nm, driven by 270 fs, 1030 nm pulses in a dual-core optical fiber exhibiting high index contrast is presented. The fiber is made of a thermally matched pair of lead silicate and borosilicate glasses used as core and cladding material, respectively. The novel switching approach is based on nonlinear balancing of dual-core asymmetry, by control pulse intensity induced group velocity reduction of the fast fiber channel. Due to the fiber core made of soft glass with high nonlinearity high switching contrast exceeding 20 dB is reached by using control pulses of only few nanojoule energy. The optimum fiber length is 14 mm, which closely match the calculated coupling length at the signal wavelength. The results express significant progress in comparison to similar studies based on self-switching of solitonic pulses in dual-core fibers and represent high application potential.

Investigation of electromechanical properties of as-electrospun polystyrene fiber mat via sequential approaching/loading technique

Electromechanically active submicron/micron polymer fibers are promising building blocks for biological/soft-robotic motion sensors and pressure sensors. In particular, mats of the fibers produced by electrospinning demonstrated distinct direct/converse electromechanical properties compared to those of films. Although several studies have demonstrated the direct electromechanical characteristics of the electromechanically active electrospun fiber mats, detailed investigation of the characteristics when the testing probe starts to contact the fiber mats, in addition to the effect on the preloading value, have not been reported. In this study, a sequential approaching/loading electromechanical testing technique has been proposed for a detailed investigation of the electromechanical properties of the fiber mats, in particular, near the contact between the testing electrode and the fiber mats. The results demonstrate that the preload and load values significantly affect the measured values of the apparent piezoelectric d constant (dapp). Therefore, careful determination of the applied preload and load values was a prerequisite for measuring the dapp of the very soft fiber mats. The present technique also demonstrates that the measured value of the capacitance of the fiber mat is significantly affected by the value of the applied load; therefore, a careful determination of the loading value is indispensable for measuring the capacitance of the fiber mats. The proposed technique can pave the way for a deep understanding of the direct electromechanical characteristics of a variety of significantly soft submicron/micron fiber mats and can aid the exploration of strategies to develop advanced biological/soft-robotic motion sensors and pressure sensors employing these mats.

Self-powered multifunctional sensing based on super-elastic fibers by soluble-core thermal drawing

The well-developed preform-to-fiber thermal drawing technique owns the benefit to maintain the cross-section architecture and obtain an individual micro-scale strand of fiber with the extended length up to thousand meters. In this work, we propose and demonstrate a two-step soluble-core fabrication method by combining such an inherently scalable manufacturing method with simple post-draw processing to explore the low viscosity polymer fibers and the potential of soft fiber electronics. As a result, an ultra-stretchable conductive fiber is achieved, which maintains excellent conductivity even under 1900% strain or 1.5 kg load/impact freefalling from 0.8-m height. Moreover, by combining with triboelectric nanogenerator technique, this fiber acts as a self-powered self-adapting multi-dimensional sensor attached on sports gears to monitor sports performance while bearing sudden impacts. Next, owing to its remarkable waterproof and easy packaging properties, this fiber detector can sense different ion movements in various solutions, revealing the promising applications for large-area undersea detection.

Morphological changes of nanofiber cross-sections due to surface tension

In the manufacturing of soft fibers at small scales, lack of considering the presence of surface tension may cause a significant shape deviation from the desired geometry due to the surface tension-induced fiber deformation. Here we develop an analytic algorithm to calculate the surface tension-induced deformation of soft nanofibers with different cross-section shapes. We prove that the displacement at the fiber cross-section boundary is independent of the cross-section size. Numerical examples demonstrate that upon surface tension nanofibers with circular cross-sections undergo radial shrinking and these with non-circular cross-sections are driven to rounder shapes. Moreover, the surface tension-induced cross-section area change is significant for non-circular soft nanofibers as their sizes fall below tens of nanometers.

Long-term In Vivo Monitoring of Chemicals with Fiber Sensors

Long-term in vivo monitoring of chemicals with implanted sensors has received considerable interests over the past decades owing to their significant contributions in reflecting health conditions and assistance in diagnosing diseases. However, the widely explored chemical sensors outside the body fail to meet the requirements of in vivo applications. This perspective reviews main challenges, recent advances and future directions of long-term in vivo monitoring of chemicals, related to immune response and sensing performance. Challenges in terms of the immune response caused by unstable interfaces between sensors and tissues and improper implanting methods, and the insufficient performance of chemical sensors in complex physiological environment are discussed. Therewith, recent advances in fabricating biocompatible, flexible and thin sensors, developing effective implanting methods with reduced injury and improving the sensitivity, selectivity and stability of chemical sensors for accurate monitoring in vivo are summarized. Finally, we propose the future directions to address these challenges by fiber chemical sensors through the combination of soft fiber configuration, facile implanting methods and new recognition elements, which will provide new platforms for health monitoring and physiological mechanism revealing.

Multifunctional Coaxial Energy Fiber toward Energy Harvesting, Storage, and Utilization.

Fibrous energy-autonomy electronics are highly desired for wearable soft electronics, human-machine interfaces, and the Internet of Things. How to effectively integrate various functional energy fibers into them and realize versatile applications is an urgent need to be fulfilled. Here, a multifunctional coaxial energy fiber has been developed toward energy harvesting, energy storage, and energy utilization. The energy fiber is composed of an all fiber-shaped triboelectric nanogenerator (TENG), supercapacitor (SC), and pressure sensor in a coaxial geometry. The inner core is a fibrous SC by a green activation strategy for energy storage; the outer sheath is a fibrous TENG in single-electrode mode for energy harvesting, and the outer friction layer and inner layer (covered with Ag) constitute a self-powered pressure sensor. The electrical performances of each energy component are systematically investigated. The fibrous SC shows a length specific capacitance density of 13.42 mF·cm-1, good charging/discharging rate capability, and excellent cycling stability (∼96.6% retention). The fibrous TENG shows a maximum power of 2.5 μW to power an electronic watch and temperature sensor. The pressure sensor has a good enough sensitivity of 1.003 V·kPa-1 to readily monitor the real-time finger motions and work as a tactile interface. The demonstrated energy fibers have exhibited stable electrochemical and mechanical performances under mechanical deformation, which make them attractive for wearable electronics. The demonstrated soft and multifunctional coaxial energy fiber is also of great significance in a sustainable human-machine interactive system, intelligent robotic skin, security tactile switches, etc.

Characterizing viscoelastic properties of synthetic and natural fibers and their coatings with a torsional pendulum.

Characterizing and understanding the viscoelastic mechanical properties of natural and synthetic fibers is of great importance in many biological and industrial applications. Microscopic techniques such as micro/nano indentation have been successfully employed in such efforts, yet these tests are often challenging to perform on fibers and come with certain limitations in the interpretation of the obtained results within the context of the macroscopic viscoelasticity in the fiber. Here we instead explore the properties of a series of natural and synthetic fibers, using a freely-oscillating torsional pendulum. The torsional oscillation of the damped mass-fiber system is precisely recorded with a simple HD video-camera and an image processing algorithm is used to analyze the resulting videos. Analysis of the processed images show a viscoelastic damped oscillatory response and a simple mechanical model describes the amplitude decay of the oscillation data very well. The natural frequency of the oscillation and the corresponding damping ratio can be extracted using a logarithmic decrement method and directly connected to the bulk viscoelastic properties of the fiber. We further study the sensitivity of these measurements to changes in the chemo-mechanical properties of the outer coating layers on one of the synthetic fibers. To quantify the accuracy of our measurements with the torsional pendulum, a complementary series of tests are also performed on a strain-controlled rheometer in both torsional and tensile deformation modes.

Optical fiber coupling of quantum dot single photon sources

Semiconductor quantum dot (QD) at low temperature will create excitons with sharp spectral lines for single photon emission. Optical fiber coupling avoids scanning for positioning and vibration influence in low-temperature confocal setup, and is a key technology in realizing the plug-play and componentization of QD single photon sources. For the fiber coupling techniques, the lateral coupling of a photonic crystal cavity or waveguide with a tapered fiber, or normal coupling of a QD chip with a tapered facet fiber in a large numerical aperture has been developed based on mask in a micro-region; however, the above techniques require multi-dimensional precise adjusting in order to avoid abnormally bending a soft fiber to realize alignment and high-efficiency coupling. Ceramic ferrule or silica V-shaped groove-mounted fiber has a large smooth facet and no bending; it can collect light in the normal direction by being aligned with bonding QD chip; V-shaped groove-mounted fiber array also enables a random adhesion and avoid scanning for alignment, which is simple in technique. This work is based on the previous realization of single photon output by random adhesion of few-pair DBR micropillar chip with V-shaped groove-mounted fiber array, and uses many-pair DBR cavity chip with theoretical simulation optimization to improve the normal light extraction and its fiber collection efficiency, and greatly improves the fiber output of single photon count rate.

Tool-use experiments to determine the function of an incised ground stone artefact with potential symbolic significance

Ground stone implements are found across most Australian landscapes and are often regarded as Aboriginal tools that were used for processing or modifying other items such as plant foods, plant fibres, resins, bone points, pigments and ground-stone axes and knives. Less common are ground stones modified for non-utilitarian, symbolic purposes; for example, polished and carved stone ornaments; ritual implements such as cylcons and tjuringa sacred stones; and unused, well-crafted ground-stone axes. In this paper, we report on the function and potential significance of an unusual ground stone artefact from a site near Bannockburn, southwestern Australia. A set of regularly spaced, shallow grooves has been cut into the surface of each side of the stone. Use-wear, residues and experimental replica tools indicate that the grooves were probably made with a stone flake and then used to shape or sharpen wooden implements such as spear points or the edges of boomerangs or other weapons. The microscopic wear outside the grooves indicates contact with soft wood or other plant material, possibly a soft plant fibre bag. We suggest that the Bannockburn artefact primarily functioned as a woodworking tool, but the even spacing of the incisions suggests that they were intentionally placed, perhaps to convey a special meaning, perhaps as a tally system or other form of communication.

ANALISIS CEMARAN MIKROBA PADA DAGING AYAM BROILER DI BEBERAPA PASAR KOTA AMBON

Chicken meat is one of the foods favored by the public because it has high nutritional content, delicious taste, affordable prices, and a soft fiber texture that makes it easy to digest. The high nutritional content can make chicken meat a good medium for the growth and development of microorganisms.The research was conducted to determine the amount of bacterial contamination in broiler meat sold in several markets in Ambon city. This study used an experimental method, namely the analysis of microbial contamination in the famous chicken meat sample in Ambon City. The research was started by taking samples of chicken breasts and thighs from various markets in Ambon city. The sample used was chicken meat that had been stored for 2 days. Furthermore, the bacterial isolation stage is carried out. The results showed that the microbial contamination in the sample of chicken breasts and thighs was still below the maximum limit (less than 1 x 106 cfu/g) determined by the National Standardization Agency. Broiler chicken meat in Ambon City is safe for consumption by the public.

Microscopic and long-wave instabilities in 3D fiber composites with non-Gaussian hyperelastic phases

We investigate the microscopic and long-wave (or macroscopic) instabilities in fiber composites (FCs) with hyperelastic phases. To study the influence of the phase stiffening behavior, we employ the phase constitutive models that are developed based on the non-Gaussian statistics of polymeric molecular chains. These non-Gaussian models accurately predict the non-linear behavior of soft materials. Moreover, they can capture the essential soft material stiffening behavior arising due to the finite extensibility of the polymer chains. In turn, the non-linear behavior of the composite phases significantly influences the elastic instabilities and the buckling patterns. Here, we illustrate the phenomenon by the example of FCs with Gent phases. We derive an explicit closed-form expression – in terms of the phase properties and composition – for the onset of long-wave instabilities. To predict the onset of finite length scale (or microscopic) instabilities, we employ the Bloch-Floquet analysis superimposed on finite deformations. We find that the matrix stiffening behavior stabilizes the composites, and can even result in an absolutely stable scenario. Remarkably, Gent FCs with identical phase stiffening characteristics are found to be more stable than their neo-Hookean counterparts for morphologies at which the microscopic instabilities are to develop first. The stiffening behavior of the phases dictates the interplay between the long-wave and microscopic instabilities, and defines the wavelength of the buckling patterns. Thus, the pre-designed phase properties can be used in tailoring the instability-induced patterns in soft fiber composites.

Vitamin K metabolism as the potential missing link between lung damage and thromboembolism in Coronavirus disease 2019.

Coronavirus disease 2019 (Covid-19), caused by severe acute respiratory syndrome coronavirus (SARS-CoV)-2, exerts far-reaching effects on public health and socio-economic welfare. The majority of infected individuals have mild to moderate symptoms, but a significant proportion develops respiratory failure due to pneumonia. Thrombosis is another frequent manifestation of Covid-19 that contributes to poor outcomes. Vitamin K plays a crucial role in the activation of both pro- and anticlotting factors in the liver and the activation of extrahepatically synthesised protein S which seems to be important in local thrombosis prevention. However, the role of vitamin K extends beyond coagulation. Matrix Gla protein (MGP) is a vitamin K-dependent inhibitor of soft tissue calcification and elastic fibre degradation. Severe extrahepatic vitamin K insufficiency was recently demonstrated in Covid-19 patients, with high inactive MGP levels correlating with elastic fibre degradation rates. This suggests that insufficient vitamin K-dependent MGP activation leaves elastic fibres unprotected against SARS-CoV-2-induced proteolysis. In contrast to MGP, Covid-19 patients have normal levels of activated factor II, in line with previous observations that vitamin K is preferentially transported to the liver for activation of procoagulant factors. We therefore expect that vitamin K-dependent endothelial protein S activation is also compromised, which would be compatible with enhanced thrombogenicity. Taking these data together, we propose a mechanism of pneumonia-induced vitamin K depletion, leading to a decrease in activated MGP and protein S, aggravating pulmonary damage and coagulopathy, respectively. Intervention trials should be conducted to assess whether vitamin K administration plays a role in the prevention and treatment of severe Covid-19.

Absolute Length Sensor Based on Time of Flight in Stretchable Optical Fibers

Soft and stretchable optical fibers are a promising all-polymer sensor element for extreme mechanical strains, pressures, bending, and other deformations. Compared to electronic sensors, the sensor elements are intrinsically stretchable and are not subject to electromagnetic interference. However, the typical approach of measuring deformation by tracking the transmitted light intensity is an integrating approach similar to resistance-based measurements; it does not provide information about the location or the nature of the deformation. This letter describes an alternate method for driving stretchable optical fibers: a consumer light detection and ranging chip connected to both ends of the fiber to measure its length via the time-of-flight (TOF) of a light pulse. This approach is a miniaturized, optics-based version of previous acoustic TOF and electronic time-domain reflectometry in robotics and human-interface devices. Such ranging systems collect spatial information using a small number of sensors. We found that the TOF approach can measure fiber lengths to within 1 mm on an overall length of ∼330 mm (>1% accuracy). Both the amplitude and TOF methods were sensitive to pressure that created microbending but in opposite directions. For bending radii greater than 7.5 mm, the TOF sensor was less sensitive to bending than the amplitude-based sensor. As a result, the TOF sensor accurately measured the perimeter of a shape with small-radius corners, while the amplitude-based sensor overreported the perimeter because of bending losses. Compared to earlier work, the TOF devices were less dependent on manufacturing variations that affected the signal level, such as fiber- source and fiber-detector alignment. We conclude that the amplitude method may be preferable for pure bending sensors, TOF sensors can distinguish pressure from stretching, and the TOF approach is notably better at measuring lengths over topography, such as in clothing-sizing and other wearable applications.