The Experts below are selected from a list of 6087 Experts worldwide ranked by ideXlab platform
Wei Jin - One of the best experts on this subject based on the ideXlab platform.
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structural polarization rocking filters in highly birefringent Microfibers
Optics Letters, 2014Co-Authors: Wa Jin, Haifeng Xuan, Wei JinAbstract:We report the first fabrication, to our knowledge, of polarization-rocking filters in highly birefringent elliptical Microfibers. A rocking filter was made by periodically heating/twisting a microfiber with an ellipticity of ∼0.7 and a diameter of ∼2.8 μm along its major axis. Strong input polarization suppression of ∼20 dB was achieved at a resonant wavelength of ∼1556.4 nm with a device length of ∼3 mm.
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tunable comb filters and refractive index sensors based on fiber loop mirror with inline high birefringence microfiber
Optics Letters, 2013Co-Authors: Wa Jin, Haifeng Xuan, Chao Wang, Wei JinAbstract:Highly birefringent (Hi-Bi) microfiber-based fiber loop mirrors (FLMs) were studied for tunable comb filters and refractive index (RI) sensors. The use of two cascaded Hi-Bi Microfibers instead of a single microfiber allows more flexibility in controlling the transmission/reflection characteristics of the FLM. The length of Hi-Bi Microfibers is of the order of centimeters, one or even more than two orders of magnitude shorter than the conventional Hi-Bi fiber-based FLM devices. The transmission/reflection spectra are sensitive to the RI surrounding the Microfibers, and RI sensitivity of 20,745 nm/RIU was experimentally demonstrated.
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co2 laser induced long period gratings in optical Microfibers
Optics Express, 2009Co-Authors: Haifeng Xuan, Wei Jin, Min ZhangAbstract:Long period gratings (LPGs) are fabricated by use of focused high frequency CO(2) laser pulses to periodically modify the transverse dimension of silica Microfibers. A 20-period LPG with a 27 dB attenuation dip is realized in a microfiber with a diameter of approximately 6.3 microm. The resonant wavelength has a negative temperature coefficient and a high sensitivity to external refractive index. The microfiber LPGs may be useful in micron scale in-fiber devices and sensors.
Claudia P Ostertag - One of the best experts on this subject based on the ideXlab platform.
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multi scale evaluation of hybrid fiber restraint of alkali silica reaction expansion in concrete
Construction and Building Materials, 2019Co-Authors: Claudia P OstertagAbstract:Abstract A multitude of deterioration mechanisms commonly associated with shortening the service life of conventional concrete structures are characterized by expansive internal forces for which a cementitious matrix is ill suited to resist. The addition of fibers has been shown to provide an effective mitigation scheme for several such expansive processes, most often in the form of high dosages of microfiber reinforcement. Hybridization of fibers of different sizes, to take advantage of their synergistic benefits, can provide an optimal balance of functional workability and enhanced mechanical performance. In this study one such hybrid fiber reinforced concrete (HyFRC) is evaluated for alkali-silica reaction mitigation, focusing first on the influence of the chosen Microfibers and subsequently on the combined effect of micro- and macrofibers with respect to expansion potential and mechanical property retention of the concrete composite. While a low dose of the Microfibers alone proved inadequate to restrain the deterioration mechanism beyond an early stage, the fiber size hybridization in HyFRC exhibited successful mitigation of expansion under standardized test conditions.
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multi scale pull out resistance of steel reinforcing bar embedded in hybrid fiber reinforced concrete hyfrc
Microelectronics Systems Education, 2017Co-Authors: A Lin, Claudia P OstertagAbstract:This paper investigates the pull-out resistance of a steel reinforcing bar embedded in a strain hardening hybrid fiber reinforced concrete that utilizes both polyvinyl alcohol (PVA) Microfibers and hooked-end steel macrofibers. Both unconfined and specimens confined with transverse steel spiral reinforcements were investigated. Pull-out tests on rebars embedded in unconfined concrete revealed brittle splitting failure whereas rebars embedded in unconfined HyFRC exhibited ductile frictional pull-out behavior. The high early rebar pull-out resistance in HyFRC is linked to an improved pull-out resistance of the steel macrofibers due to the micro/macrofiber synergy. Steel macrofiber pull-out tests revealed that the PVA Microfibers are very effective in enhancing the pull-out resistance of the steel macrofibers which then lead to an overall performance enhancement of the rebar pull-out resistance.
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effect of steel Microfibers on corrosion of steel reinforcing bars
Cement and Concrete Research, 2007Co-Authors: J A Grubb, Claudia P Ostertag, Joshua Blunt, T M DevineAbstract:Steel microfiber reinforcement was previously found to be successful in mitigating alkali silica reaction in concrete, an expansive phenomenon. The use of steel Microfibers to mitigate rebar corrosion, another expansive reaction, was investigated. Mortar specimens with and without steel microfiber reinforcement were exposed to a corrosive environment. All specimens were prepared with water/cement ratios of both 0.40 and 0.55, cured for 28 days, and then submerged in aerated 3.5% NaCl solution. The corrosion behavior of the specimens was monitored via electrochemical measurements. Three types of electrochemical tests were performed: corrosion potential measurements, potentiodynamic polarization, and electrochemical impedance spectroscopy. Chloride concentration measurements and microscopic analysis were performed as well. The polarization curves, Tafel, and polarization resistance measurements indicate that the steel rebar in the microfiber-reinforced mortars are more resistant to corrosion than the rebar in the control mortars, despite higher chloride concentrations. Furthermore, the steel microfiber-reinforced cement based materials have a lower electrolytic resistance. This is not indicative of a higher corrosion rate, which would be the case if it had been observed in standard mortar specimens.
Joan E Sanders - One of the best experts on this subject based on the ideXlab platform.
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Polymer microfiber mechanical properties: A system for assessment and investigation of the link with fibrous capsule formation
Journal of biomedical materials research. Part A, 2003Co-Authors: Joan E Sanders, Brian S. Nicholson, Stuart B. Mitchell, Robert E. LedgerAbstract:A novel microtensile testing instrument was developed to assess the mechanical properties of small-diameter polyethylene, polyurethane, and polyester Microfibers. The instrument had a root-mean-square error of 2.96 μN for force measurement and 1.91 μm for displacement measurement. Microfibers ranging in diameter from 1.0 to 10.9 μm were strained at 2 mm/s in the device, and the slopes of their stress–strain curves (material moduli) were determined. Correlations between material modulus and previously published data on fibrous capsule presence and thickness for implanted polyethylene, polyurethane, and polyester Microfibers were investigated. Results for the 1.0–5.9-μm microfiber diameter range showed that neither the percentage of unencapsulated fibers nor the capsule thickness correlated well with modulus. Correlation coefficients were 0.04 and 0.09, respectively. However, for the 6.0–10.9 μm diameter range the correlations were strong, 1.00 for both percentage of unencapsulated fibers and capsule thickness. It is suggested that the results reflect the greater attachment and mechanical interaction of cells with Microfibers for the 6.0–10.9 μm-diameter range than for the 1.0–5.9 μm-diameter range. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 67A: 1412–1416, 2003
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relative influence of polymer fiber diameter and surface charge on fibrous capsule thickness and vessel density for single fiber implants
Journal of Biomedical Materials Research Part A, 2003Co-Authors: Joan E Sanders, Damon V Cassisi, Thomas Neumann, Stephen L Golledge, S G Zachariah, Buddy D Ratner, S D BaleAbstract:Single polypropylene Microfibers plasma-coated with polymers of different surface charge [N,N-dimethylaminoethyl methacrylate (NN) (positive charge), methacrylic acid (MA) (negative charge), and hexafluoropropylene (HF) (neutral)] were implanted in the subcutaneous dorsum of Sprague-Dawley rats for 5-week intervals. Thee groups of fiber diameters were used: (I) 1.0 to 5.9 μm; (II) 6.0 to 10.9 μm; and (III) 11.0 to 15.9 μm. Fibrous capsule thickness and blood-vessel density (number of vessels within 100 μm of the fiber) were assessed in tissue sections in the planes of microfiber cross-sections. Results from a multifactorial analysis of variance demonstrated statistically significant main effects (p < 0.05) for microfiber diameter but not for surface-charge coating. The mean differences in capsule thickness among the microfiber diameter groups were: between groups II and I: 5.4 μm; between groups III and I: 10.2 μm; and between groups III and II: 4.7 μm. The mean differences in capsule thickness among surface-charge coatings were: between MA and NN: 0.7 μm; between MA and HF: 1.4 μm; and between NN and HF: 0.7 μm. Many of the 1.0 to 5.9 μm-in-diameter fibers had no capsule and no sign of a foreign-body reaction. For the vessel density analysis, neither microfiber diameter nor surface-charge coating had a statistically significant effect. Thus the geometric feature of microfiber diameter was more important than was surface charge relative to fibrous capsule formation but not relative to local vessel density. This ranking of the relative influence of design features in relation to tissue response provides useful information for prioritization in biomaterial design. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 65A: 462–467, 2003
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Relative influence of polymer fiber diameter and surface charge on fibrous capsule thickness and vessel density for single-fiber implants
Journal of biomedical materials research. Part A, 2003Co-Authors: Joan E Sanders, Damon V Cassisi, Thomas Neumann, Stephen L Golledge, S G Zachariah, Buddy D Ratner, S D BaleAbstract:Single polypropylene Microfibers plasma-coated with polymers of different surface charge [N,N-dimethylaminoethyl methacrylate (NN) (positive charge), methacrylic acid (MA) (negative charge), and hexafluoropropylene (HF) (neutral)] were implanted in the subcutaneous dorsum of Sprague-Dawley rats for 5-week intervals. Thee groups of fiber diameters were used: (I) 1.0 to 5.9 microm; (II) 6.0 to 10.9 microm; and (III) 11.0 to 15.9 microm. Fibrous capsule thickness and blood-vessel density (number of vessels within 100 microm of the fiber) were assessed in tissue sections in the planes of microfiber cross-sections. Results from a multifactorial analysis of variance demonstrated statistically significant main effects (p < 0.05) for microfiber diameter but not for surface-charge coating. The mean differences in capsule thickness among the microfiber diameter groups were: between groups II and I: 5.4 microm; between groups III and I: 10.2 microm; and between groups III and II: 4.7 microm. The mean differences in capsule thickness among surface-charge coatings were: between MA and NN: 0.7 microm; between MA and HF: 1.4 microm; and between NN and HF: 0.7 microm. Many of the 1.0 to 5.9 microm-in-diameter fibers had no capsule and no sign of a foreign-body reaction. For the vessel density analysis, neither microfiber diameter nor surface-charge coating had a statistically significant effect. Thus the geometric feature of microfiber diameter was more important than was surface charge relative to fibrous capsule formation but not relative to local vessel density. This ranking of the relative influence of design features in relation to tissue response provides useful information for prioritization in biomaterial design.
Haifeng Xuan - One of the best experts on this subject based on the ideXlab platform.
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structural polarization rocking filters in highly birefringent Microfibers
Optics Letters, 2014Co-Authors: Wa Jin, Haifeng Xuan, Wei JinAbstract:We report the first fabrication, to our knowledge, of polarization-rocking filters in highly birefringent elliptical Microfibers. A rocking filter was made by periodically heating/twisting a microfiber with an ellipticity of ∼0.7 and a diameter of ∼2.8 μm along its major axis. Strong input polarization suppression of ∼20 dB was achieved at a resonant wavelength of ∼1556.4 nm with a device length of ∼3 mm.
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tunable comb filters and refractive index sensors based on fiber loop mirror with inline high birefringence microfiber
Optics Letters, 2013Co-Authors: Wa Jin, Haifeng Xuan, Chao Wang, Wei JinAbstract:Highly birefringent (Hi-Bi) microfiber-based fiber loop mirrors (FLMs) were studied for tunable comb filters and refractive index (RI) sensors. The use of two cascaded Hi-Bi Microfibers instead of a single microfiber allows more flexibility in controlling the transmission/reflection characteristics of the FLM. The length of Hi-Bi Microfibers is of the order of centimeters, one or even more than two orders of magnitude shorter than the conventional Hi-Bi fiber-based FLM devices. The transmission/reflection spectra are sensitive to the RI surrounding the Microfibers, and RI sensitivity of 20,745 nm/RIU was experimentally demonstrated.
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co2 laser induced long period gratings in optical Microfibers
Optics Express, 2009Co-Authors: Haifeng Xuan, Wei Jin, Min ZhangAbstract:Long period gratings (LPGs) are fabricated by use of focused high frequency CO(2) laser pulses to periodically modify the transverse dimension of silica Microfibers. A 20-period LPG with a 27 dB attenuation dip is realized in a microfiber with a diameter of approximately 6.3 microm. The resonant wavelength has a negative temperature coefficient and a high sensitivity to external refractive index. The microfiber LPGs may be useful in micron scale in-fiber devices and sensors.
S D Bale - One of the best experts on this subject based on the ideXlab platform.
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relative influence of polymer fiber diameter and surface charge on fibrous capsule thickness and vessel density for single fiber implants
Journal of Biomedical Materials Research Part A, 2003Co-Authors: Joan E Sanders, Damon V Cassisi, Thomas Neumann, Stephen L Golledge, S G Zachariah, Buddy D Ratner, S D BaleAbstract:Single polypropylene Microfibers plasma-coated with polymers of different surface charge [N,N-dimethylaminoethyl methacrylate (NN) (positive charge), methacrylic acid (MA) (negative charge), and hexafluoropropylene (HF) (neutral)] were implanted in the subcutaneous dorsum of Sprague-Dawley rats for 5-week intervals. Thee groups of fiber diameters were used: (I) 1.0 to 5.9 μm; (II) 6.0 to 10.9 μm; and (III) 11.0 to 15.9 μm. Fibrous capsule thickness and blood-vessel density (number of vessels within 100 μm of the fiber) were assessed in tissue sections in the planes of microfiber cross-sections. Results from a multifactorial analysis of variance demonstrated statistically significant main effects (p < 0.05) for microfiber diameter but not for surface-charge coating. The mean differences in capsule thickness among the microfiber diameter groups were: between groups II and I: 5.4 μm; between groups III and I: 10.2 μm; and between groups III and II: 4.7 μm. The mean differences in capsule thickness among surface-charge coatings were: between MA and NN: 0.7 μm; between MA and HF: 1.4 μm; and between NN and HF: 0.7 μm. Many of the 1.0 to 5.9 μm-in-diameter fibers had no capsule and no sign of a foreign-body reaction. For the vessel density analysis, neither microfiber diameter nor surface-charge coating had a statistically significant effect. Thus the geometric feature of microfiber diameter was more important than was surface charge relative to fibrous capsule formation but not relative to local vessel density. This ranking of the relative influence of design features in relation to tissue response provides useful information for prioritization in biomaterial design. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 65A: 462–467, 2003
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Relative influence of polymer fiber diameter and surface charge on fibrous capsule thickness and vessel density for single-fiber implants
Journal of biomedical materials research. Part A, 2003Co-Authors: Joan E Sanders, Damon V Cassisi, Thomas Neumann, Stephen L Golledge, S G Zachariah, Buddy D Ratner, S D BaleAbstract:Single polypropylene Microfibers plasma-coated with polymers of different surface charge [N,N-dimethylaminoethyl methacrylate (NN) (positive charge), methacrylic acid (MA) (negative charge), and hexafluoropropylene (HF) (neutral)] were implanted in the subcutaneous dorsum of Sprague-Dawley rats for 5-week intervals. Thee groups of fiber diameters were used: (I) 1.0 to 5.9 microm; (II) 6.0 to 10.9 microm; and (III) 11.0 to 15.9 microm. Fibrous capsule thickness and blood-vessel density (number of vessels within 100 microm of the fiber) were assessed in tissue sections in the planes of microfiber cross-sections. Results from a multifactorial analysis of variance demonstrated statistically significant main effects (p < 0.05) for microfiber diameter but not for surface-charge coating. The mean differences in capsule thickness among the microfiber diameter groups were: between groups II and I: 5.4 microm; between groups III and I: 10.2 microm; and between groups III and II: 4.7 microm. The mean differences in capsule thickness among surface-charge coatings were: between MA and NN: 0.7 microm; between MA and HF: 1.4 microm; and between NN and HF: 0.7 microm. Many of the 1.0 to 5.9 microm-in-diameter fibers had no capsule and no sign of a foreign-body reaction. For the vessel density analysis, neither microfiber diameter nor surface-charge coating had a statistically significant effect. Thus the geometric feature of microfiber diameter was more important than was surface charge relative to fibrous capsule formation but not relative to local vessel density. This ranking of the relative influence of design features in relation to tissue response provides useful information for prioritization in biomaterial design.