Fibers2014, 2(3), 211-220; doi:10.3390/fib2030211 - published online 14 July 2014 Show/Hide Abstract
Abstract: An investigation of the relationships among fiber linear density, tenacity, and structure is important to help cotton breeders modify varieties for enhanced fiber end-use qualities. This study employed the Stelometer instrument, which is the traditional fiber tenacity reference method and might still be an option as a rapid screening tool because of its low cost and portable attributes. In addition to flat bundle break force and weight variables from a routine Stelometer test, the number of fibers in the bundle were counted manually and the fiber crystallinity (CIIR) was characterized by the previously proposed attenuated total reflection-sampling device based Fourier transform infrared (ATR-FTIR) protocol. Based on the plots of either tenacity vs. linear density or fiber count vs. mass, the fibers were subjectively divided into fine or coarse sets, respectively. Relative to the distinctive increase in fiber tenacity with linear density, there was an unclear trend between the linear density and CIIR for these fibers. Samples with similar linear density were found to increase in tenacity with fiber CIIR. In general, Advanced Fiber Information System (AFIS) fineness increases with fiber linear density.
Fibers2014, 2(3), 187-210; doi:10.3390/fib2030187 - published online 30 June 2014 Show/Hide Abstract
Abstract: When nanomaterials enter biological fluids, they are immediately covered by biomolecules, particularly proteins, forming the so-called protein corona. The dynamic nature and complexity of the protein corona can impact upon the biological effects and distribution of nanomaterials with an organism. Therefore, the protein corona is an important factor in determining the biological impact of any nanomaterials. The protein adsorption pattern is determined by various factors, including the bio-fluids’ protein composition, the nanomaterials’ physicochemical properties, as well as the time and type of exposure. Predominantly, research has focused upon spherical nano-objects, however, due to their ever-increasing potential use within human based applications, and, therefore, heightening and inevitable exposure to the human body, little is known regarding how proteins interact with nanofibers. Therefore, the present review focuses on the current knowledge as to how the geometry of man-made (nano)fibers, carbon nanotubes (in comparison with asbestos fibers), affects their interaction with proteins within biological fluids. Summarizing state-of the art methodologies applied to dissect protein-binding signatures, it is further discussed whether the protein corona composition of fibrous and non-fibrous materials differ, as well as what impact the protein corona has on (nano)fiber uptake, intracellular distribution and their subsequent toxicity.
Fibers2014, 2(2), 158-186; doi:10.3390/fib2020158 - published online 30 April 2014 Show/Hide Abstract
Abstract: Electrospinning is a rapidly growing polymer processing technology as it provides a viable and simple method to create ultra-fine continuous fibers. This paper presents an in-depth review of the mechanical properties of electrospun fibers and particularly focuses on methodologies to generate high strength and high modulus nanofibers. As such, it aims to provide some guidance to future research activities in the area of high performance electrospun fibers.
Fibers2014, 2(2), 150-157; doi:10.3390/fib2020150 - published online 16 April 2014 Show/Hide Abstract
Abstract: In the article a novel construction of a side-detecting luminescent optical fiber for an UV sensor application has been presented. In the fiber, structure phosphate glass doped with 0.5 mol% Tb3+ ions was used as a UV sensitive core/ribbon. The luminescence spectrum of glass and the optical fiber was measured under UV excitation using a deuterium lamp. It was found that large energy gap between upper (metastable) and lower (ground) levels of terbium ions incorporated in phosphate matrix leads to the effective emission at wavelengths of 489, 543, 586 and 621 nm, which correspond to 5D4 → 7FJ, (J = 3, 4, 5, 6) transitions respectively. Phosphate glass doped with optimal (the strongest VIS emission) concentration of Tb3+ (0.5 mol%) was used as the active core/ribbon in the construction of UV side-detecting optical fiber.
Fibers2014, 2(2), 142-149; doi:10.3390/fib2020142 - published online 14 April 2014 Show/Hide Abstract
Abstract: An ultra-high sensitive strain sensor is proposed. The sensing head, based on the post-processing of a fiber Bragg grating, is used to perform passive and active strain measurements. Both wavelength and full width half maximum dependences with the applied strain are studied for the passive sensor, where maximum sensitivities of 104.1 pm/µε and 61.6 pm/µε are respectively obtained. When combining the high performance of this sensor with a ring laser cavity configuration, the Bragg grating will act as a filter and high resolution measurements can be performed. With the proposed sensor, a resolution of 700 nε is achieved.
Fibers2014, 2(2), 128-141; doi:10.3390/fib2020128 - published online 10 April 2014 Show/Hide Abstract
Abstract: To reduce particulate matter (PM) in diesel exhaust gas, a diesel particulate filter (DPF) has been developed. The thermal durability of existing platinum catalyst-supported DPFs is inadequate. We are focusing on a non-catalytic after-treatment of silicon carbide (SiC) fibers with highly thermal durability. In this study, we simulated the processes of soot deposition and oxidation. Results show that even in exhaust gas without soot, a complex flow pattern is observed. The porosity of the filter is not constant along the flow direction, and the pressure gradient varies. The friction factor is slightly larger than the predicted value by the empirical equation in uniform porous media flow. Since the soot deposition occurs inside the filter, the depth filtration by SiC fibers was confirmed. In addition, the effects of filter temperature and oxygen concentration are clearly revealed. That is, comparing the oxidation at 700 °C, the deposited soot amount at 1200 and 1400 °C is decreased by 60% and 92%, respectively. Raising the oxygen concentration from 10% to 20% increases the oxidation efficiency from 42% to 64%. Although more work is needed over a wide range of operating conditions, a combination of these two parameters is important to achieve the non-catalytic exhaust after-treatment.