In this paper, a review of microstructured optical fiber (MOF) sensors is given. Various kinds of MOFs are described and their sensing applications are summarized. Two main types of MOF sensors in ...terms of grating based and interferometry based are reviewed. In particular, several types of microstructured optical fibers designed for sensing applications in our works are demonstrated, including the measurement of physical parameters, e.g., pressure, strain, torsion, temperature, and the detection of biomedical parameters such as refractive index and microfluidic flow rate. The basic design principles of MOF sensors based on fiber Bragg grating and interferometers are given. Comparisons of the performances of the fibers and sensors are also conducted according to the relevant topics.
Man‐made continuous fibers play an essential role in society today. With the increase in global sustainability challenges, there is a broad spectrum of societal needs where the development of ...advanced biobased fibers could provide means to address the challenges. Biobased regenerated fibers, produced from dissolved cellulose are widely used today for clothes, upholstery, and linens. With new developments in the area of advanced biobased fibers, it would be possible to compete with high‐performance synthetic fibers such as glass fibers and carbon fibers as well as to provide unique functionalities. One possible development is to fabricate fibers by spinning filaments from nanocellulose, Nature's nanoscale high‐performance building block, which will require detailed insights into nanoscale assembly mechanisms during spinning, as well as knowledge regarding possible functionalization. If successful, this could result in a new class of man‐made biobased fibers. This work aims to identify the progress made in the field of spinning of nanocellulose filaments, as well as outline necessary steps for efficient fabrication of such nanocellulose‐based filaments with controlled and predictable properties.
Nanocellulose presents an opportunity for the development of a new class of man‐made biobased fibers that can replace high‐performance fossil‐based fibers, as well as provide fibers with new advanced functionalities. Promising material concepts are available, but successful scale‐up will need more profound insights into the mechanisms that control nanoscale assembly during processing.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
We present a novel design approach to reduce the overall microstructure diameter (MSD) of multi-layered anti-resonant hollow-core fiber (AR-HCF) while maintaining their exceptional optical ...performance. By strategically truncating the outermost layer of the large tubular element in the AR-HCF structure by a central angle of 130o, the MSD is reduced by 16% compared to its intact tube design counterpart. The fabricated truncated AR-HCF demonstrates a minimum loss of 0.28 ± 0.1 dB/km at 1290 nm and below 0.5 dB/km in the O-band from 1220-1340 nm. A similar truncated AR-HCF designed for C-band operation achieves 0.23 ± 0.1 dB/km around 1550 nm. Furthermore, the fiber exhibits low dispersion, negligible bending loss, and satisfactory higher-order mode extinction capability. This truncated AR-HCF design with reduced MSD strikes an optimal balance between exceptional optical performance and ease of integration, expanding the versatility of AR-HCFs across diverse applications like communications, sensing, and laser technologies.
The increasing global environmental concerns and awareness of renewable green resources is continuously expanding the demand for eco-friendly, sustainable and biodegradable natural fibre reinforced ...composites (NFRCs). Natural fibres already occupy an important place in the composite industry due to their excellent physicochemical and mechanical properties. Natural fibres are biodegradable, biocompatible, eco-friendly and created from renewable resources. Therefore, they are extensively used in place of expensive and non-renewable synthetic fibres, such as glass fibre, carbon fibre and aramid fibre, in many applications. Additionally, the NFRCs are used in automobile, aerospace, personal protective clothing, sports and medical industries as alternatives to the petroleum-based materials. To that end, in the last few decades numerous studies have been carried out on the natural fibre reinforced composites to address the problems associated with the reinforcement fibres, polymer matrix materials and composite fabrication techniques in particular. There are still some drawbacks to the natural fibre reinforced composites (NFRCs)—for example, poor interfacial adhesion between the fibre and the polymer matrix, and poor mechanical properties of the NFRCs due to the hydrophilic nature of the natural fibres. An up-to-date holistic review facilitates a clear understanding of the behaviour of the composites along with the constituent materials. This article intends to review the research carried out on the natural fibre reinforced composites over the last few decades. Furthermore, up-to-date encyclopaedic information about the properties of the NFRCs, major challenges and potential measures to overcome those challenges along with their prospective applications have been exclusively illustrated in this review work. Natural fibres are created from plant, animal and mineral-based sources. The plant-based cellulosic natural fibres are more economical than those of the animal-based fibres. Besides, these pose no health issues, unlike mineral-based fibres. Hence, in this review, the NFRCs fabricated with the plant-based cellulosic fibres are the main focus.
We demonstrate the first multiterabit/s wavelength division multiplexing data transmission through hollow-core antiresonant fiber (HC-ARF). In total, 16 channels of 32-GBd dual-polarization ...Nyquist-shaped 256QAM signal channels were transmitted through a 270-m-long fiber without observing any power penalty. In a single-channel high power transmission experiment, no nonlinearity penalty was observed for up to 1 W of received power, despite the very low chromatic dispersion of the fiber (<;2 ps/nm/km). Our simulations show that such a low level of nonlinearity should enable transmission at 6.4 Tb/s over 1200 km of HC-ARF, even when the fiber attenuation is significantly greater than that of SMF-28. As signals propagate through hollow-core fibers at close to the speed of light in vacuum such a link would be of interest in latency-sensitive data transmission applications.
The recent status of Japan's government-driven project to establish carbon fiber reinforced thermoplastic composites (CFRTP) technology for automotive applications conducted in the National ...Composites Center (NCC) Japan is introduced first. The baseline technology is discontinuous carbon fiber reinforced thermoplastic composites (C-LFT-D: carbon – long fiber thermoplastic-direct) using press compaction. All the components of the target car chassis made of aluminum alloy are replaced by C-LFT-D components and a 10% weight reduction with the same rigidity has been verified. The basic physics of the fiber length distribution mechanism and the experimental procedures to measure fiber length distributions are proposed. A basic theory to predict the flow behavior of extruded raw material of the mixture of melted resin and thermoplastics is proposed, and sophisticated CAE software to predict the flow patterns of the raw material is established. Measured elastic moduli of processed LFT-D plates show strong dependency on local fiber orientations and strong correlations between bending strengths and bending modulus are found. Hence, prediction of fiber orientation in the press compaction is a key point of the design of LFT-D components. The viscoelastic properties of C-LFT-D materials are characterized by using established theories. Certain important parameters, such as the shift factors, are identified by theory and experiments. The basic concepts of joining technology are also established, where ultrasonic fusion bonding is selected as the primary method. Joining procedures are defined and mechanical properties of the joints are evaluated. The essence of the other project conducted in the University of Tokyo for CFRTP applications to automobiles is also introduced. Several new composites are developed and evaluation technologies are developed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The optical and structural properties of boron nitride nanotube (BNNT) assembly were characterized using optical fiber Bragg grating (FBG) sensors. FBGs were fabricated in tapered fibers with a ...diameter of less than 30 μm. After tapered fibers were etched in hydrofluoric acid solution for a few minutes, BNNTs were then deposited on the fibers through a dip-coating process. The Bragg wavelengths of the FBGs were measured before and after BNNT coating such that the effective refractive index (RI) of the guided fundamental HE11 mode in the fiber was obtained. By numerical modeling of the dependence of HE11 mode effective RI on the RI of the surrounding material, both the RI and the air void content of BNNT coating were obtained. To verify the accuracy of the modeling results, a FBG sensor fabricated in a tapered fiber was immerged in various RI standard solutions and the corresponding Bragg wavelengths were measured and compared to numerical simulations. It was shown that the experimental data agreed well with simulation results.
This paper presents a linear least squares method for fiber-longitudinal power profile estimation (PPE), which estimates the optical signal power distribution throughout a fiber-optic link at a ...coherent receiver. The method finds the global optimum in the least squares estimation of the longitudinal power profiles; thus, its results closely match the true optical power profiles and locate loss anomalies in a link with high spatial resolution. Experimental results show that the method achieves accurate PPE with an RMS error of 0.18 dB from OTDR. Consequently, it successfully identifies a loss anomaly as small as 0.77 dB, demonstrating the potential of a coherent receiver in locating even splice and connector losses. The method is also evaluated under WDM conditions with optimal system fiber launch power, highlighting its feasibility for use in practical operations. Furthermore, the fundamental limit for stable estimation and the spatial resolution of least-squares-based PPE are quantitatively discussed in relation to the ill-posedness of the PPE by evaluating the condition number of the nonlinear perturbation matrix.
The loss of skeletal muscle mass with aging has been attributed to a decline in muscle fiber number and muscle fiber size.
To define to what extent differences in leg muscle cross-sectional area ...(CSA) between young and elderly men are attributed to differences in muscle fiber size.
Quadriceps muscle CSA and type I and type II muscle fiber size were measured in healthy young (n=25; 23±1y) and older (n=26; 71±1y) men. Subsequently, the older subjects performed 6months of resistance type exercise training, after which measurements were repeated. Differences in quadriceps muscle CSA were compared with differences in type I and type II muscle fiber size.
Quadriceps CSA was substantially smaller in older versus young men (68±2 vs 80±2cm2, respectively; P<0.001). Type II muscle fiber size was substantially smaller in the elderly vs the young (29%; P<0.001), with a tendency of smaller type I muscle fibers (P=0.052). Differences in type II muscle fiber size fully explained differences in quadriceps CSA between groups. Prolonged resistance type exercise training in the elderly increased type II muscle fiber size by 24±8% (P<0.01), explaining 100±3% of the increase in quadriceps muscle CSA (from 68±2 to 74±2cm2).
Reduced muscle mass with aging is mainly attributed to smaller type II muscle fiber size and, as such, is unlikely accompanied by substantial muscle fiber loss. In line, the increase in muscle mass following prolonged resistance type exercise training can be attributed entirely to specific type II muscle fiber hypertrophy.
► Age-related differences in muscle size can be attributed to smaller muscle fibers. ► Training-induced increase in muscle size is attributed to muscle fiber hypertrophy. ► Large in muscle fiber numbers changes in aging or after training are unlikely. ► Interventions for sarcopenia should target type II muscle fiber hypertrophy.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
30.
High Power Fiber Lasers: A Review Zervas, Michalis N.; Codemard, Christophe A.
IEEE journal of selected topics in quantum electronics,
09/2014, Volume:
20, Issue:
5
Journal Article
Peer reviewed
In this paper, we summarize the fundamental properties and review the latest developments in high power fiber lasers. The review is focused primarily on the most common fiber laser configurations and ...the associated cladding pumping issues. Special attention is placed on pump combination techniques and the parameters that affect the brightness enhancement observed in single-mode and multimode high power fiber lasers. The review includes the major limitations imposed by fiber nonlinearities and other parasitic effects, such as optical damage, transverse modal instabilities and photodarkening. Finally, the paper summarizes the power evolution in continuous-wave and pulsed ytterbium-doped fiber lasers and their impact on industrial applications.
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