Use of Carbon Nano-Fiber Foams as Strain Gauges to Detect Crack Propagation

DTIC Science & Technology

2015-06-01

FIBER FOAMS AS STRAIN GAUGES TO DETECT CRACK PROPAGATION by Ervin N. Mercado June 2015 Thesis Advisor: Claudia C. Luhrs Co-Advisor...AND DATES COVERED Master’s Thesis 4. TITLE AND SUBTITLE USE OF CARBON NANO-FIBER FOAMS AS STRAIN GAUGES TO DETECT CRACK PROPAGATION 5. FUNDING...using carbon nanofiber foams as strain gauge material to detect crack propagation in aluminum structures. We produced the tridimensional carbon

Plasmonic Optical Fiber Sensor Based on Double Step Growth of Gold Nano-Islands

PubMed Central

Vasconcelos, Helena

2018-01-01

It is presented the fabrication and characterization of optical fiber sensors for refractive index measurement based on localized surface plasmon resonance (LSPR) with gold nano-islands obtained by single and by repeated thermal dewetting of gold thin films. Thin films of gold deposited on silica (SiO2) substrates and produced by different experimental conditions were analyzed by Scanning Electron Microscope/Dispersive X-ray Spectroscopy (SEM/EDS) and optical means, allowing identifying and characterizing the formation of nano-islands. The wavelength shift sensitivity to the surrounding refractive index of sensors produced by single and by repeated dewetting is compared. While for the single step dewetting, a wavelength shift sensitivity of ~60 nm/RIU was calculated, for the repeated dewetting, a value of ~186 nm/RIU was obtained, an increase of more than three times. It is expected that through changing the fabrication parameters and using other fiber sensor geometries, higher sensitivities may be achieved, allowing, in addition, for the possibility of tuning the plasmonic frequency. PMID:29677108

Plasmonic Optical Fiber Sensor Based on Double Step Growth of Gold Nano-Islands.

PubMed

de Almeida, José M M M; Vasconcelos, Helena; Jorge, Pedro A S; Coelho, Luis

2018-04-20

It is presented the fabrication and characterization of optical fiber sensors for refractive index measurement based on localized surface plasmon resonance (LSPR) with gold nano-islands obtained by single and by repeated thermal dewetting of gold thin films. Thin films of gold deposited on silica (SiO₂) substrates and produced by different experimental conditions were analyzed by Scanning Electron Microscope/Dispersive X-ray Spectroscopy (SEM/EDS) and optical means, allowing identifying and characterizing the formation of nano-islands. The wavelength shift sensitivity to the surrounding refractive index of sensors produced by single and by repeated dewetting is compared. While for the single step dewetting, a wavelength shift sensitivity of ~60 nm/RIU was calculated, for the repeated dewetting, a value of ~186 nm/RIU was obtained, an increase of more than three times. It is expected that through changing the fabrication parameters and using other fiber sensor geometries, higher sensitivities may be achieved, allowing, in addition, for the possibility of tuning the plasmonic frequency.

Electrospray neutralization process and apparatus for generation of nano-aerosol and nano-structured materials

DOEpatents

Bailey, Charles L.; Morozov, Victor; Vsevolodov, Nikolai N.

2010-08-17

The claimed invention describes methods and apparatuses for manufacturing nano-aerosols and nano-structured materials based on the neutralization of charged electrosprayed products with oppositely charged electrosprayed products. Electrosprayed products include molecular ions, nano-clusters and nano-fibers. Nano-aerosols can be generated when neutralization occurs in the gas phase. Neutralization of electrospan nano-fibers with molecular ions and charged nano-clusters may result in the formation of fibrous aerosols or free nano-mats. Nano-mats can also be produced on a suitable substrate, forming efficient nano-filters.

Room-temperature aqueous plasma electrolyzing Al2O3 nano-coating on carbon fiber

NASA Astrophysics Data System (ADS)

Zhang, Yuping; Meng, Yang; Shen, Yonghua; Chen, Weiwei; Cheng, Huanwu; Wang, Lu

2017-10-01

A novel room-temperature aqueous plasma electrolysis technique has been developed in order to prepared Al2O3 nano-coating on each fiber within a carbon fiber bundle. The microstructure and formation mechanism of the Al2O3 nano-coating were systematically investigated. The oxidation resistance and tensile strength of the Al2O3-coated carbon fiber was measured at elevated temperatures. It showed that the dense Al2O3 nano-coating was relatively uniformly deposited with 80-120 nm in thickness. The Al2O3 nano-coating effectively protected the carbon fiber, evidenced by the slower oxidation rate and significant increase of the burn-out temperature from 800 °C to 950 °C. Although the bare carbon fiber remained ∼25 wt.% after oxidation at 700 °C for 20 min, a full destruction was observed, evidenced by the ∼0 GPa of the tensile strength, compared to ∼1.3 GPa of the Al2O3-coated carbon fiber due to the effective protection from the Al2O3 nano-coating. The formation mechanism of the Al2O3 nano-coating on carbon fiber was schematically established mainly based on the physic-chemical effect in the cathodic plasma arc zone.

Cotton fibers nano-TiO{sub 2} composites prepared by as-assembly process and the photocatalytic activities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xia, J.H., E-mail: xiajianhan@163.com; Hsu, C.T.; Qin, D.D.

Graphical abstract: Display Omitted Highlights: ► TiO{sub 2} nanoparticles self-assemble process under the assistant of carboxylic group. ► The carboxylic group was introduced by displacement reaction. ► The loading amount of nano-TiO{sub 2} was depended on the displacement degree of C-6-OH. ► UV–Vis experiments showed these fibers had efficient photocatalysis. ► The degradation reaction Rhodamine 6G under UV light obeys zero-order rate law. -- Abstract: This paper describes photocatalytic cotton fibers produced by a TiO{sub 2} nanoparticle self-assembly process with the assistance of carboxylic groups. The carboxylic group was introduced by a displacement reaction, the molecular structure of the glucosemore » unit was studied by utilizing solid {sup 13}C NMR. The appearance of the prepared fibers was observed by scanning electron microscopy, it was found that nano-TiO{sub 2} coated uniformly on the fiber surface. The loading amount of nano-TiO{sub 2} was depended on the displacement degree of C-6-OH. UV–Vis experiments showed these coated fibers undergo photocatalysis efficiently. The degradation reaction of Rhodamine 6G under UV light obeys the zero-order rate law.« less

Study of the Emission Characteristics of Single-Walled CNT and Carbon Nano-Fiber Pyrograf III

NASA Astrophysics Data System (ADS)

Mousa, Marwan S.; Al-Akhras, M.-Ali H.; Daradkeh, Samer

2018-02-01

Field emission microscopy measurements from Single-Walled Carbon Nanotubes (SWCNTs) and Carbon Nano-Fibers Pyrograf III PR-1 (CNF) were performed. Details of the materials employed in the experiments are as follows: (a) Carbon Nano-Fibers Pyrograf III PR-1 (CNF), having an average fiber diameter that is ranging between (100-200) nm with a length of (30-100) μm. (b) Single walled Carbon Nanotubes were produced by high-pressure CO over Fe particle (HiPCO: High-Pressure Carbon Monoxide process), having an average diameter ranging between (1-4) nm with a length of (1-3) μm. The experiments were performed under vacuum pressure value of (10-7 mbar). The research work reported here includes the field electron emission current-voltage (I-V) characteristics and presented as Fowler-Nordheim (FN) plots and the spatial emission current distributions (electron emission images) obtained and analyzed in terms of electron source features. For both the SWCNT and the CNF a single spot pattern for the electron spatial; distributions were observed.

Development and characterization of nano-fiber patch for the treatment of glaucoma.

PubMed

Gagandeep; Garg, Tarun; Malik, Basant; Rath, Goutam; Goyal, Amit K

2014-03-12

In the present work polymeric nano-fiber patches was developed for the effective treatment of glaucoma using timolol maleate and dorzolamide hydrochloride as model drugs. The nano-fibers were prepared by electrospinning technique and were characterized on the basis of fiber diameter, morphology, entrapment efficiency, mucoadhesive strength, and drug release behavior, etc. Final formulations were inserted in the cul-de-sac of glaucoma induced rabbits and the efficacy of the formulation was evaluated. The results clearly indicated the potential of the developed formulation for occur drug delivery. There was a significant fall in the intraocular pressure compared to commercial eye drops. Copyright © 2013 Elsevier B.V. All rights reserved.

Large-scale and highly efficient synthesis of micro- and nano-fibers with controlled fiber morphology by centrifugal jet spinning for tissue regeneration

NASA Astrophysics Data System (ADS)

Ren, Liyun; Pandit, Vaibhav; Elkin, Joshua; Denman, Tyler; Cooper, James A.; Kotha, Shiva P.

2013-02-01

PLLA fibrous tissue scaffolds with controlled fiber nanoscale surface roughness are fabricated with a novel centrifugal jet spinning process. The centrifugal jet spinning technique is a highly efficient synthesis method for micron- to nano-sized fibers with a production rate up to 0.5 g min-1. During the centrifugal jet spinning process, a polymer solution jet is stretched by the centrifugal force of a rotating chamber. By engineering the rheological properties of the polymer solution, solvent evaporation rate and centrifugal force that are applied on the solution jet, polyvinylpyrrolidone (PVP) and poly(l-lactic acid) (PLLA) composite fibers with various diameters are fabricated. Viscosity measurements of polymer solutions allowed us to determine critical polymer chain entanglement limits that allow the generation of continuous fiber as opposed to beads or beaded fibers. Above a critical concentration at which polymer chains are partially or fully entangled, lower polymer concentrations and higher centrifugal forces resulted in thinner fibers. Etching of PVP from the PLLA-PVP composite fibers doped with increasing PVP concentrations yielded PLLA fibers with increasing nano-scale surface roughness and porosity, which increased the fiber hydrophilicity dramatically. Scanning electron micrographs of the etched composite fibers suggest that PVP and PLLA were co-contiguously phase separated within the composite fibers during spinning and nano-scale roughness features were created after the partial etching of PVP. To study the tissue regeneration efficacy of the engineered PLLA fiber matrix, human dermal fibroblasts are used to simulate partial skin graft. Fibers with increased PLLA surface roughness and porosity demonstrated a trend towards higher cell attachment and proliferation.PLLA fibrous tissue scaffolds with controlled fiber nanoscale surface roughness are fabricated with a novel centrifugal jet spinning process. The centrifugal jet spinning technique is a

Method of producing nano-scaled inorganic platelets

DOEpatents

Zhamu, Aruna; Jang, Bor Z.

2012-11-13

The present invention provides a method of exfoliating a layered material (e.g., transition metal dichalcogenide) to produce nano-scaled platelets having a thickness smaller than 100 nm, typically smaller than 10 nm. The method comprises (a) dispersing particles of a non-graphite laminar compound in a liquid medium containing therein a surfactant or dispersing agent to obtain a stable suspension or slurry; and (b) exposing the suspension or slurry to ultrasonic waves at an energy level for a sufficient length of time to produce separated nano-scaled platelets. The nano-scaled platelets are candidate reinforcement fillers for polymer nanocomposites.

Comparative properties of cellulose nano-crystals from native and mercerized cotton fibers

USDA-ARS?s Scientific Manuscript database

Stable aqueous suspensions of cellulose nano-crystals (CNCs) were fabricated from both native and mercerized cotton fibers by sulfuric acid hydrolysis, followed by high-pressure homogenization. Fourier Transform Infrared Spectrometry and Wide-angle X-Ray Diffraction data showed that the fibers had b...

Investigation of mechanical properties of hemp/glass fiber reinforced nano clay hybrid composites

NASA Astrophysics Data System (ADS)

Unki, Hanamantappa Ningappa; Shivanand, H. K.; Vidyasagar, H. N.

2018-04-01

Over the last twenty to thirty years composite materials have been used in engineering field. Composite materials possess high strength, high strength to weight ratio due to these facts composite materials are becoming popular among researchers and scientists. The major proportion of engineering materials consists of composite materials. Composite materials are used in vast applications ranging from day-to-day household articles to highly sophisticated applications. In this paper an attempt is made to prepare three different composite materials using e-glass and Hemp. In this present investigation hybrid composite of Hemp, Glass fiber and Nano clay will be prepared by Hand-layup technique. The glass fiber used in this present investigation is E-glass fiber bi-directional: 90˚ orientation. The composite samples will be made in the form of a Laminates. The wt% of nanoclay added in the preparation of sample is 20 gm constant. The fabricated composite Laminate will be cut into corresponding profiles as per ASTM standards for Mechanical Testing. The effect of addition of Nano clay and variation of Hemp/glass fibers will be studied. In the present work, a new Hybrid composite is developed in which Hemp, E glass fibers is reinforced with epoxy resin and with Nano clay.

Vertically aligned cobalt hydroxide nano-flake coated electro-etched carbon fiber cloth electrodes for supercapacitors

NASA Astrophysics Data System (ADS)

Cheng, Qian; Tang, Jie; Zhang, Han; Qin, Lu-Chang

2014-11-01

We describe preparation and characterization of nanostructured electrodes using Co(OH)2 nano-flakes and carbon fiber cloth for supercapacitors. Nanostructured Co(OH)2 flakes are produced by electrodeposition and they are coated onto the electro-etched carbon fiber cloth. A highest specific capacitance of 3404.8 F g-1 and an area-normalized specific capacitance of 3.3 F cm-2 have been obtained from such electrodes. Morphology and structure of the nanostructured electrodes have been characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electrochemical properties have been studied by cyclic voltammetry (CV), constant-current charge and discharge, electrochemical impedance spectroscopy (EIS), and long-time cycling.

Fiber Bragg grating filter using evaporated induced self assembly of silica nano particles

NASA Astrophysics Data System (ADS)

Hammarling, Krister; Zhang, Renyung; Manuilskiy, Anatoliy; Nilsson, Hans-Erik

2014-03-01

In the present work we conduct a study of fiber filters produced by evaporation of silica particles upon a MM-fiber core. A band filter was designed and theoretically verified using a 2D Comsol simulation model of a 3D problem, and calculated in the frequency domain in respect to refractive index. The fiber filters were fabricated by stripping and chemically etching the middle part of an MM-fiber until the core was exposed. A mono layer of silica nano particles were evaporated on the core using an Evaporation Induced Self-Assembly (EISA) method. The experimental results indicated a broader bandwidth than indicated by the simulations which can be explained by the mismatch in the particle size distributions, uneven particle packing and finally by effects from multiple mode angles. Thus, there are several closely connected Bragg wavelengths that build up the broader bandwidth. The experimental part shows that it is possible by narrowing the particle size distributing and better control of the particle packing, the filter effectiveness can be greatly improved.

Well-ordered polymer nano-fibers with self-cleaning property by disturbing crystallization process

NASA Astrophysics Data System (ADS)

Yang, Qin; Luo, Zhuangzhu; Tan, Sheng; Luo, Yimin; Wang, Yunjiao; Zhang, Zhaozhu; Liu, Weimin

2014-07-01

Bionic self-cleaning surfaces with well-ordered polymer nano-fibers are firstly fabricated by disturbing crystallization during one-step coating-curing process. Orderly thin (100 nm) and long (5-10 μm) polymer nano-fibers with a certain direction are fabricated by external macroscopic force ( F blow) interference introduced by H2 gas flow, leading to superior superhydrophobicity with a water contact angle (WCA) of 170° and a water sliding angle (WSA) of 0-1°. In contrast, nano-wires and nano-bridges (1-8 μm in length/10-80 nm in width) are generated by "spinning/stretching" under internal microscopic force ( F T) interference due to significant temperature difference in the non-uniform cooling medium. The findings provide a novel theoretical basis for controllable polymer "bionic lotus" surface and will further promote practical application in many engineering fields such as drag-reduction and anti-icing.

Well-ordered polymer nano-fibers with self-cleaning property by disturbing crystallization process.

PubMed

Yang, Qin; Luo, Zhuangzhu; Tan, Sheng; Luo, Yimin; Wang, Yunjiao; Zhang, Zhaozhu; Liu, Weimin

2014-01-01

Bionic self-cleaning surfaces with well-ordered polymer nano-fibers are firstly fabricated by disturbing crystallization during one-step coating-curing process. Orderly thin (100 nm) and long (5-10 μm) polymer nano-fibers with a certain direction are fabricated by external macroscopic force (F blow) interference introduced by H2 gas flow, leading to superior superhydrophobicity with a water contact angle (WCA) of 170° and a water sliding angle (WSA) of 0-1°. In contrast, nano-wires and nano-bridges (1-8 μm in length/10-80 nm in width) are generated by "spinning/stretching" under internal microscopic force (F T) interference due to significant temperature difference in the non-uniform cooling medium. The findings provide a novel theoretical basis for controllable polymer "bionic lotus" surface and will further promote practical application in many engineering fields such as drag-reduction and anti-icing.

Use of polypropylene fibers coated with nano-silica particles into a cementitious mortar

DOE Office of Scientific and Technical Information (OSTI.GOV)

Coppola, B., E-mail: bcoppola@unisa.it; Di Maio, L.; Scarfato, P.

Fiber reinforced cementitious composite (FRCC) materials have been widely used during last decades in order to overcome some of traditional cementitious materials issues: brittle behaviour, fire resistance, cover spalling, impact strength. For composite materials, fiber/matrix bond plays an important role because by increasing fiber/matrix interactions is possible to increase the behaviour of the entire material. In this study, in order to improve fiber to matrix adhesion, two chemical treatments of polypropylene fibers were investigated: alkaline hydrolysis and nano-silica sol-gel particles deposition. Treatmtents effect on fibers morphology and mechanical properties was investigated by scanning electron microscopy (SEM) and tensile tests. SEMmore » investigations report the presence of spherical nano-silica particles on fiber surface, in the case of sol-gel process, while alkaline hydrolysis leads to an increase of fibers roughness. Both treatments have negligible influence on fibers mechanical properties confirming the possibility of their use in a cementitious mortar. Pullout tests were carried out considering three embedded length of fibers in mortar samples (10, 20 and 30 mm, respectively) showing an increase of pullout energy for treated fibers. The influence on fiber reinforced mortar mechanical properties was investigated by three-point flexural tests on prismatic specimens considering two fibers length (15 and 30 mm) and two fibers volume fractions (0.50 and 1.00 %). A general increase of flexural strength over the reference mix was achieved and an overall better behaviour is recognizable for mortars containing treated fibers.« less

Study of SBS slow light based on nano-material doped fiber

NASA Astrophysics Data System (ADS)

Zhang, Ying; Lang, Pei-Lin; Zhang, Ru

2009-03-01

A novel optical fiber doped with nano material InP is manufactured by the modified chemical vapor deposition (MCVD). The slow light based on stimulated Brillouin scattering (SBS) in the optical fiber is studied. The results show that a time delay of ˜738 ps is obtained when the input Stokes pulse is 900 ps(FWHM) and the SBS gain is ˜15. It shows that a considerable time delay and an amplification of the input light can be achieved by this novel optical fiber.

Single and dual fiber nano-tip optical tweezers: trapping and analysis.

PubMed

Decombe, Jean-Baptiste; Huant, Serge; Fick, Jochen

2013-12-16

An original optical tweezers using one or two chemically etched fiber nano-tips is developed. We demonstrate optical trapping of 1 micrometer polystyrene spheres at optical powers down to 2 mW. Harmonic trap potentials were found in the case of dual fiber tweezers by analyzing the trapped particle position fluctuations. The trap stiffness was deduced using three different models. Consistent values of up to 1 fN/nm were found. The stiffness linearly decreases with decreasing light intensity and increasing fiber tip-to-tip distance.

Using graphene nano-particle embedded in photonic crystal fiber for evanescent wave mode-locking of fiber laser.

PubMed

Lin, Yung-Hsiang; Yang, Chun-Yu; Liou, Jia-Hong; Yu, Chin-Ping; Lin, Gong-Ru

2013-07-15

A photonic crystal fiber (PCF) with high-quality graphene nano-particles uniformly dispersed in the hole cladding are demonstrated to passively mode-lock the erbium-doped fiber laser (EDFL) by evanescent-wave interaction. The few-layer graphene nano-particles are obtained by a stabilized electrochemical exfoliation at a threshold bias. These slowly and softly exfoliated graphene nano-particle exhibits an intense 2D band and an almost disappeared D band in the Raman scattering spectrum. The saturable phenomena of the extinction coefficient β in the cladding provides a loss modulation for the intracavity photon intensity by the evanescent-wave interaction. The evanescent-wave mode-locking scheme effectively enlarges the interaction length of saturable absorption with graphene nano-particle to provide an increasing transmittance ΔT of 5% and modulation depth of 13%. By comparing the core-wave and evanescent-wave mode-locking under the same linear transmittance, the transmittance of the graphene nano-particles on the end-face of SMF only enlarges from 0.54 to 0.578 with ΔT = 3.8% and the modulation depth of 10.8%. The evanescent wave interaction is found to be better than the traditional approach which confines the graphene nano-particles at the interface of two SMF patchcords. When enlarging the intra-cavity gain by simultaneously increasing the pumping current of 980-nm and 1480-nm pumping laser diodes (LDs) to 900 mA, the passively mode-locked EDFL shortens its pulsewidth to 650 fs and broadens its spectral linewidth to 3.92 nm. An extremely low carrier amplitude jitter (CAJ) of 1.2-1.6% is observed to confirm the stable EDFL pulse-train with the cladding graphene nano-particle based evanescent-wave mode-locking.

Development and characterization of sugarcane bagasse fiber and nano-silica reinforced epoxy hybrid composites

NASA Astrophysics Data System (ADS)

Fong, A. L.; Khandoker, N. A. N.; Debnath, S.

2018-04-01

This paper presents an experimental study on the mechanical performance of sugarcane bagasse fiber reinforced epoxy composite. Tensile and flexural properties of the composites were investigated in this research. Different weightage of short fiber and fiber particulates were utilized to study their effects on the mechanical performance of the composites in terms of tensile and flexural properties. 1% of nano-silica was reinforced to investigate its effect on the mechanical performance of the composites. Hand lay-up composite molding process was used to fabricate the composite samples. During fabrication, ultrasonic mixing was carried out to study the effects on mechanical performance of the fiber particulate reinforced composites. In overall, ultrasonic mixing and addition of nano-silica particles has improved the mechanical performance of the fiber particulate composites. Morphology analysis on surface of composites has shown the removal of air bubbles and deagglomeration. 1wt% of short fiber reinforced composite exhibits the highest tensile and flexural properties among all the samples. Sugarcane bagasse particulates reinforced composites were shown to have better performance compared to short fiber reinforced composites when the wt% of the fiber increase.

Methods for producing silicon carbide fibers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garnier, John E.; Griffith, George W.

Methods of producing silicon carbide fibers. The method comprises reacting a continuous carbon fiber material and a silicon-containing gas in a reaction chamber at a temperature ranging from approximately 1500.degree. C. to approximately 2000.degree. C. A partial pressure of oxygen in the reaction chamber is maintained at less than approximately 1.01.times.10.sup.2 Pascal to produce continuous alpha silicon carbide fibers. Continuous alpha silicon carbide fibers and articles formed from the continuous alpha silicon carbide fibers are also disclosed.

Hybrid Fiber Layup and Fiber-Reinforced Polymeric Composites Produced Therefrom

NASA Technical Reports Server (NTRS)

Barnell, Thomas J. (Inventor); Garrigan, Sean P. (Inventor); Rauscher, Michael D. (Inventor); Dietsch, Benjamin A. (Inventor); Cupp, Gary N. (Inventor)

2018-01-01

Embodiments of a hybrid fiber layup used to form a fiber-reinforced polymeric composite, and a fiber-reinforced polymeric composite produced therefrom are disclosed. The hybrid fiber layup comprises one or more dry fiber strips and one or more prepreg fiber strips arranged side by side within each layer, wherein the prepreg fiber strips comprise fiber material impregnated with polymer resin and the dry fiber strips comprise fiber material without impregnated polymer resin.

Mechanical Characterization of Electrospun Nanocomposite Fibers

NASA Astrophysics Data System (ADS)

Alsmairat, Ohood

Electrospinning is considered one of the most efficient techniques used for producing fibers in the nanometer to micrometer ranges. The mechanical properties of the electrospun fibers depend on the solution used to produce them. The present study focuses on dissolving the PolyMethalylmethacrylate (PMMA) in acetone solvent. A concentration of 23% PMMA was found to be the best concentration for producing smooth fibers with almost no beads. We studied the effect of mixing the PMMA with two types of nanotubes on the mechanical properties of the fibers. A Carbon-Nano-Tubes (CNT) and Boron-Nitride-Nano-Tubes were mixed with PMMA solution at different ratios to produce a CNT/PMMA and BNNT/PMMA solutions with different concentrations of 0.1%, 0.25%, and 0.6%. Electrospinning technique was used to produce fibers from the PMMA, CNT/PMMA, and BNNT/PMMA solutions. All fibers were tested experimentally with a micro-tensile-tester to produce stress-strain curves that were used to extract the average modulus of elasticity, maximum strength, and fracture point for each fiber. Enhancements in the Youngs modulus and maximum tensile strength of the fibers were observed with the addition of CNTs. Further enhancements were observed with the addition of BNNTs. A random sample of 0.6% CNT/PMMA fibers was tested with Raman spectrometer and the results show a linear change in the frequency-strain curve.

Nano-Aramid Fiber Reinforced Polyurethane Foam

NASA Technical Reports Server (NTRS)

Semmes, Edmund B.; Frances, Arnold

2008-01-01

Closed cell polyurethane and, particularly, polyisocyanurate foams are a large family of flexible and rigid products the result of a reactive two part process wherein a urethane based polyol is combined with a foaming or "blowing" agent to create a cellular solid at room temperature. The ratio of reactive components, the constituency of the base materials, temperature, humidity, molding, pouring, spraying and many other processing techniques vary greatly. However, there is no known process for incorporating reinforcing fibers small enough to be integrally dispersed within the cell walls resulting in superior final products. The key differentiating aspect from the current state of art resides in the many processing technologies to be fully developed from the novel concept of milled nano pulp aramid fibers and their enabling entanglement capability fully enclosed within the cell walls of these closed cell urethane foams. The authors present the results of research and development of reinforced foam processing, equipment development, strength characteristics and the evolution of its many applications.

Nano-displacement sensor based on photonic crystal fiber modal interferometer.

PubMed

Dash, Jitendra Narayan; Jha, Rajan; Villatoro, Joel; Dass, Sumit

2015-02-15

A stable nano-displacement sensor based on large mode area photonic crystal fiber (PCF) modal interferometer is presented. The compact setup requires simple splicing of a small piece of PCF with a single mode fiber (SMF). The excitation and recombination of modes is carried out in a single splice. The use of a reflecting target creates an extra cavity that discretizes the interference pattern of the mode interferometer, boosting the displacement resolution to nanometer level. The proposed modal interferometric based displacement sensor is highly stable and shows sensitivity of 32  pm/nm.

Glass fiber manufacturing and fiber safety: the producer's perspective.

PubMed Central

Bender, J R; Hadley, J G

1994-01-01

Historically, the potential health effects of airborne fibers have been associated with the dose, dimension, and durability. Increasing focus is being placed on the latter category. Concern about airborne fiber safety could be reduced by manufacturing fibers that are not respirable; however, due to performance and manufacturing constraints on glasswool insulations, this is not possible today. These products are an important part of today's economy and as a major manufacturer, Owens-Corning is committed to producing and marketing materials that are both safe and effective in their intended use. To this end, manufacturing technology seeks to produce materials that generate low concentrations of airborne fibers, thus minimizing exposure and irritation. The range of fiber diameters is controlled to assure effective product performance and, as far as possible, to minimize respirability. Glass compositions are designed to allow effective fiber forming and ultimate product function. Fiber dissolution is primarily a function of composition; this too, can be controlled within certain constraints. Coupled with these broad parameters is an extensive product stewardship program to assure the safety of these materials. This article will discuss the factors that influence glasswool insulation production, use, and safety. PMID:7882953

Hybrid optical fiber add-drop filter based on wavelength dependent light coupling between micro/nano fiber ring and side-polished fiber

PubMed Central

Yu, Jianhui; Jin, Shaoshen; Wei, Qingsong; Zang, Zhigang; Lu, Huihui; He, Xiaoli; Luo, Yunhan; Tang, Jieyuan; Zhang, Jun; Chen, Zhe

2015-01-01

In this paper, we report our experimental study on directly coupling a micro/nano fiber (MNOF) ring with a side-polished fiber(SPF). As a result of the study, the behavior of an add-drop filter was observed. The demonstrated add-drop filter explored the wavelength dependence of light coupling between a MNOF ring and a SPF. The characteristics of the filter and its performance dependence on the MNOF ring diameter were investigated experimentally. The investigation resulted in an empirically obtained ring diameter that showed relatively good filter performance. Since light coupling between a (MNOF) and a conventional single mode fiber has remained a challenge in the photonic integration community, the present study may provide an alternative way to couple light between a MNOF device and a conventional single mode fiber based device or system. The hybridization approach that uses a SPF as a platform to integrate a MNOF device may enable the realization of other all-fiber optical hybrid devices. PMID:25578467

Hybrid optical fiber add-drop filter based on wavelength dependent light coupling between micro/nano fiber ring and side-polished fiber

NASA Astrophysics Data System (ADS)

Yu, Jianhui; Jin, Shaoshen; Wei, Qingsong; Zang, Zhigang; Lu, Huihui; He, Xiaoli; Luo, Yunhan; Tang, Jieyuan; Zhang, Jun; Chen, Zhe

2015-01-01

In this paper, we report our experimental study on directly coupling a micro/nano fiber (MNOF) ring with a side-polished fiber(SPF). As a result of the study, the behavior of an add-drop filter was observed. The demonstrated add-drop filter explored the wavelength dependence of light coupling between a MNOF ring and a SPF. The characteristics of the filter and its performance dependence on the MNOF ring diameter were investigated experimentally. The investigation resulted in an empirically obtained ring diameter that showed relatively good filter performance. Since light coupling between a (MNOF) and a conventional single mode fiber has remained a challenge in the photonic integration community, the present study may provide an alternative way to couple light between a MNOF device and a conventional single mode fiber based device or system. The hybridization approach that uses a SPF as a platform to integrate a MNOF device may enable the realization of other all-fiber optical hybrid devices.

Hybrid optical fiber add-drop filter based on wavelength dependent light coupling between micro/nano fiber ring and side-polished fiber.

PubMed

Yu, Jianhui; Jin, Shaoshen; Wei, Qingsong; Zang, Zhigang; Lu, Huihui; He, Xiaoli; Luo, Yunhan; Tang, Jieyuan; Zhang, Jun; Chen, Zhe

2015-01-12

In this paper, we report our experimental study on directly coupling a micro/nano fiber (MNOF) ring with a side-polished fiber(SPF). As a result of the study, the behavior of an add-drop filter was observed. The demonstrated add-drop filter explored the wavelength dependence of light coupling between a MNOF ring and a SPF. The characteristics of the filter and its performance dependence on the MNOF ring diameter were investigated experimentally. The investigation resulted in an empirically obtained ring diameter that showed relatively good filter performance. Since light coupling between a (MNOF) and a conventional single mode fiber has remained a challenge in the photonic integration community, the present study may provide an alternative way to couple light between a MNOF device and a conventional single mode fiber based device or system. The hybridization approach that uses a SPF as a platform to integrate a MNOF device may enable the realization of other all-fiber optical hybrid devices.

High-rate nano-crystalline Li 4Ti 5O 12 attached on carbon nano-fibers for hybrid supercapacitors

NASA Astrophysics Data System (ADS)

Naoi, Katsuhiko; Ishimoto, Shuichi; Isobe, Yusaku; Aoyagi, Shintaro

A lithium titanate (Li 4Ti 5O 12)-based electrode which can operate at unusually high current density (300 C) was developed as negative electrode for hybrid capacitors. The high-rate Li 4Ti 5O 12 electrode has a unique nano-structure consisting of unusually small nano-crystalline Li 4Ti 5O 12 (ca. 5-20 nm) grafted onto carbon nano-fiber anchors (nc-Li 4Ti 5O 12/CNF). This nano-structured nc-Li 4Ti 5O 12/CNF composite are prepared by simple sol-gel method under ultra-centrifugal force (65,000 N) followed by instantaneous annealing at 900 °C for 3 min. A model hybrid capacitor cell consisting of a negative nc-Li 4Ti 5O 12/CNF composite electrode and a positive activated carbon electrode showed high energy density of 40 Wh L -1 and high power density of 7.5 kW L -1 comparable to conventional EDLCs.

Kenaf bast cellulosic fibers hierarchy: a comprehensive approach from micro to nano.

PubMed

Karimi, Samaneh; Tahir, Paridah Md; Karimi, Ali; Dufresne, Alain; Abdulkhani, Ali

2014-01-30

Cellulosic fibers from kenaf bast were isolated in three distinct stages. Initially raw kenaf bast fibers were subjected to an alkali pulping process. Then pulped fibers undergone a bleaching process and finally both pulped and bleached fibers were separated into their constituent nanoscale cellulosic fibers by mechanical shearing. The influence of each treatment on the chemical composition of fibers was investigated. Moreover morphology, functional groups, crystallinity, and thermal behavior of fiber hierarchy at different stages of purification were studied using scanning and transmission electron microscopies, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA), respectively. Microscopy studies revealed that applied procedures successfully isolated nanoscale cellulosic fibers from both unbleached and bleached pulps. Chemical composition analysis and FTIR spectroscopy showed that lignin and hemicellulose were almost entirely removed by the applied treatments. XRD and TGA analyses demonstrated progressive enhancement of properties in fibers, hierarchically, in going from micro to nano scale. Interestingly no significant evolution was observed between obtained data of characterized ubnleached and bleached nanofibers. Copyright © 2013 Elsevier Ltd. All rights reserved.

Fire performance of fiber board coated with nano kaolin-clay film

Treesearch

Zhijia Liu; John F. Hunt; Zhiyong Cai

2013-01-01

Fiberboard is a common interior material used both in China and the United States of America. The increase in demand for interior materials has raised concerns regarding combustibility of the materials. The pyrolysis characteristics of fiber, phenolic resin (PF), and nano kaolin-clay (NK) were investigated using thermogravimetry. The fire performances of samples coated...

Preparation of High Mechanical Performance Nano-Fe3O4/Wood Fiber Binderless Composite Boards for Electromagnetic Absorption via a Facile and Green Method

PubMed Central

Dang, Baokang; Chen, Yipeng; Wang, Hanwei; Chen, Bo; Jin, Chunde; Sun, Qingfeng

2018-01-01

Fe3O4/wood fiber composites are prepared with a green mechanical method using only distilled water as a solvent without any chemical agents, and then a binderless composite board with high mechanical properties is obtained via a hot-press for electromagnetic (EM) absorption. The fibers are connected by hydrogen bonds after being mechanically pretreated, and Fe3O4 nanoparticles (NPs) are attached to the fiber surface through physical adsorption. The composite board is bonded by an adhesive, which is provided by the reaction of fiber composition under high temperature and pressure. The Nano-Fe3O4/Fiber (NFF) binderless composite board shows remarkable microwave absorption properties and high mechanical strength. The optional reflection loss (RL) of the as-prepared binderless composite board is −31.90 dB. The bending strength of the NFF binderless composite board is 36.36 MPa with the addition of 6% nano-Fe3O4, the modulus of elasticity (MOE) is 6842.16 MPa, and the internal bond (IB) strength is 0.81 MPa. These results demonstrate that magnetic nanoparticles are deposited in binderless composite board by hot pressing, which is the easiest way to produce high mechanical strength and EM absorbers. PMID:29361726

Experimental and numerical characterization of scalable cellulose nano-fiber composite

NASA Astrophysics Data System (ADS)

Barari, Bamdad

Fiber-reinforced polymer composites have been used in recent years as an alternative to the conventional materials because of their low weight, high mechanical properties and low processing temperatures. Most polymer composites are traditionally made using reinforcing fibers such as carbon or glass fibers. However, there has been recent interest in making these reinforcing fibers from natural resources. The plant-derived cellulose nano-fibers (CNF) are a material with remarkable mechanical properties at the nano-scale that are much superior to the mechanical properties of the traditional natural fibers (such as jute, hemp, kenaf, etc) used in the natural-fiber based polymer composites. Because CNF is bio-based and biodegradable, it is an attractive 'green' alternative for use in automotive, aerospace, and other engineering applications. However, efforts to produce CNF based nano-composites, with successful scaling-up of the remarkable nanoscale properties of CNF, have not met with much success and form an active area of research. The main goals of this research are to characterize the scalable CNF based nano composites using experimental methods and to develop effective models for flow of polymeric resin in the CNF-based porous media used during the proposed manufacture of CNF nano-composites. In the CNF composite characterization section, scalable isotropic and anisotropic CNF composites were made from a porous CNF preforms created using a freeze drying process. Formation of the fibers during freeze-drying process can change the micro skeleton of the final preform structure as non-aligned or isotropic and aligned or anisotropic CNF. Liquid Composite Molding (LCM) processes form a set of liquid molding technologies that are used quite commonly for making the conventional polymer composites. An improvised vacuum-driven LCM process was used to make the CNF-based nanocomposites from CNF preforms using a 'green' epoxy resin with high bio-content. Under the topic of

Long distance, distributed gas sensing based on micro-nano fiber evanescent wave quartz-enhanced photoacoustic spectroscopy

NASA Astrophysics Data System (ADS)

He, Ying; Ma, Yufei; Tong, Yao; Yu, Xin; Peng, Zhenfang; Gao, Jing; Tittel, Frank K.

2017-12-01

A long distance, distributed gas sensing using the micro-nano fiber evanescent wave (FEW) quartz enhanced photoacoustic spectroscopy technique was demonstrated. Such a sensor scheme has the advantages of higher detection sensitivity, distributed gas sensing ability, lower cost, and a simpler fabrication procedure compared to conventional FEW gas sensors using a photonic crystal fiber or a tapered fiber with chemical sputtering. A 3 km single mode fiber with multiple tapers and an erbium doped fiber amplifier with an output optical power of 700 mW were employed to perform long distance, distributed gas measurements.

Methods of producing continuous boron carbide fibers

DOEpatents

Garnier, John E.; Griffith, George W.

2015-12-01

Methods of producing continuous boron carbide fibers. The method comprises reacting a continuous carbon fiber material and a boron oxide gas within a temperature range of from approximately 1400.degree. C. to approximately 2200.degree. C. Continuous boron carbide fibers, continuous fibers comprising boron carbide, and articles including at least a boron carbide coating are also disclosed.

Dual-wavelength nano-engineered Thulium-doped fiber laser via bending of singlemode-multimode-singlemode fiber structure

NASA Astrophysics Data System (ADS)

Zulkifli, A. Z.; Latiff, A. A.; Paul, M. C.; Yasin, M.; Ahmad, H.; Harun, S. W.

2016-12-01

In this paper, a dual-wavelength fiber laser (DWFL) using nano-engineered Thulium-doped fiber as a gain medium with a bent singlemode-multimode-singlemode fiber structure (SMS) is demonstrated. The SMS structure is packaged systematically using Cr-39 polymer plates to provide linear bending via applied load. Experimental results have proved that the bent SMS is capable to provide highly effective wavelength filter and wavelengths stabilizer by balancing the net cavity gain between the two wavelengths. The DWFL provides very narrow spacing of 0.9 nm, narrow 3 dB spectral linewidth of ∼0.07 nm and SNR of ∼42 dB. Based on stability test, very small mode hopping is observed at the two wavelengths having deviations of ±0 nm and ±0.04 nm respectively. In conjunction, the DWFL provides very stable relative wavelength spacing with a deviation of ±0.04 nm.

Flexural toughness of steel fiber reinforced high performance concrete containing nano-SiO2 and fly ash.

PubMed

Zhang, Peng; Zhao, Ya-Nan; Li, Qing-Fu; Wang, Peng; Zhang, Tian-Hang

2014-01-01

This paper aims to clarify the effect of steel fiber on the flexural toughness of the high performance concrete containing fly ash and nano-SiO2. The flexural toughness was evaluated by two methods, which are based on ASTM C1018 and DBV-1998, respectively. By means of three-point bending method, the flexural toughness indices, variation coefficients of bearing capacity, deformation energy, and equivalent flexural strength of the specimen were measured, respectively, and the relational curves between the vertical load and the midspan deflection (P(V)-δ) were obtained. The results indicate that steel fiber has great effect on the flexural toughness parameters and relational curves (P(V)-δ) of the three-point bending beam specimen. When the content of steel fiber increases from 0.5% to 2%, the flexural toughness parameters increase gradually and the curves are becoming plumper and plumper with the increase of steel fiber content, respectively. However these flexural toughness parameters begin to decrease and the curves become thinner and thinner after the steel fiber content exceeds 2%. It seems that the contribution of steel fiber to the improvement of flexural toughness of the high performance concrete containing fly ash and nano-SiO2 is well performed only when the steel fiber content is less than 2%.

Controlled chemical stabilization of polyvinyl precursor fiber, and high strength carbon fiber produced therefrom

DOEpatents

Naskar, Amit K.

2016-12-27

Method for the preparation of carbon fiber, which comprises: (i) immersing functionalized polyvinyl precursor fiber into a liquid solution having a boiling point of at least 60.degree. C.; (ii) heating the liquid solution to a first temperature of at least 25.degree. C. at which the functionalized precursor fiber engages in an elimination-addition equilibrium while a tension of at least 0.1 MPa is applied to the fiber; (iii) gradually raising the first temperature to a final temperature that is at least 20.degree. C. above the first temperature and up to the boiling point of the liquid solution for sufficient time to convert the functionalized precursor fiber to a pre-carbonized fiber; and (iv) subjecting the pre-carbonized fiber produced according to step (iii) to high temperature carbonization conditions to produce the final carbon fiber. Articles and devices containing the fibers, including woven and non-woven mats or paper forms of the fibers, are also described.

Flexural Toughness of Steel Fiber Reinforced High Performance Concrete Containing Nano-SiO2 and Fly Ash

PubMed Central

Zhao, Ya-Nan; Li, Qing-Fu; Wang, Peng; Zhang, Tian-Hang

2014-01-01

This paper aims to clarify the effect of steel fiber on the flexural toughness of the high performance concrete containing fly ash and nano-SiO2. The flexural toughness was evaluated by two methods, which are based on ASTM C1018 and DBV-1998, respectively. By means of three-point bending method, the flexural toughness indices, variation coefficients of bearing capacity, deformation energy, and equivalent flexural strength of the specimen were measured, respectively, and the relational curves between the vertical load and the midspan deflection (P V-δ) were obtained. The results indicate that steel fiber has great effect on the flexural toughness parameters and relational curves (P V-δ) of the three-point bending beam specimen. When the content of steel fiber increases from 0.5% to 2%, the flexural toughness parameters increase gradually and the curves are becoming plumper and plumper with the increase of steel fiber content, respectively. However these flexural toughness parameters begin to decrease and the curves become thinner and thinner after the steel fiber content exceeds 2%. It seems that the contribution of steel fiber to the improvement of flexural toughness of the high performance concrete containing fly ash and nano-SiO2 is well performed only when the steel fiber content is less than 2%. PMID:24883395

Resin impregnation process for producing a resin-fiber composite

NASA Technical Reports Server (NTRS)

Palmer, Raymond J. (Inventor); Moore, William E. (Inventor)

1994-01-01

Process for vacuum impregnation of a dry fiber reinforcement with a curable resin to produce a resin-fiber composite, by drawing a vacuum to permit flow of curable liquid resin into and through a fiber reinforcement to impregnate same and curing the resin-impregnated fiber reinforcement at a sufficient temperature and pressure to effect final curing. Both vacuum and positive pressure, e.g. autoclave pressure, are applied to the dry fiber reinforcement prior to application of heat and prior to any resin flow to compact the dry fiber reinforcement, and produce a resin-fiber composite of reduced weight, thickness and resin content, and improved mechanical properties. Preferably both a vacuum and positive pressure, e.g. autoclave pressure, are also applied during final curing.

Effects of Structural Properties of Electrospun TiO2 Nano-fiber Meshes on their Osteogenic Potential

PubMed Central

Wang, Xiaokun; Gittens, Rolando A.; Song, Rosemary; Tannenbaum, Rina; Olivares-Navarrete, Rene; Schwartz, Zvi; Chen, Haifeng; Boyan, Barbara D.

2011-01-01

Ideal outcomes in the field of tissue engineering and regenerative medicine involve biomaterials that can enhance cell differentiation and production of local factors for natural tissue regeneration without the use of systemic drugs. Biomaterials typically used in tissue engineering applications include polymeric scaffolds that mimic the 3-D structural environment of the native tissue, but these are often functionalized with proteins or small peptides to improve their biological performance. For bone applications, titanium (Ti) implants, or more appropriately the titania (TiO2) passive oxide layer formed on their surface, have been shown to enhance osteoblast differentiation in vitro and to promote osseointegration in vivo. In this study we evaluated the effect on osteoblast differentiation of pure TiO2 nano-fiber meshes with different surface micro-roughness and nano-fiber diameters, prepared by the electrospinning method. MG63 cells were seeded on TiO2 meshes, and cell number, differentiation markers and local factor production were analyzed. The results showed that cells grew throughout the entire surfaces and with similar morphology in all groups. Cell number was sensitive to surface micro-roughness, whereas cell differentiation and local factor production was regulated by both surface roughness and nano-fiber diameter. These results indicate that scaffold structural cues alone can be used to drive cell differentiation and create an osteogenic environment without the use of exogenous factors. PMID:22075122

Development of fine-celled bio-fiber composite foams using physical blowing agents and nano-particles

NASA Astrophysics Data System (ADS)

Guo, Gangjian

As one of eco-friendly bio-fibers, wood-fiber has been incorporated in plastics to make wood-fiber/plastic composites (WPC) with an increased stiffness, durability and lowered cost. However, these improvements are usually accompanied by loss in the ductility and impact strength of the composites. These shortcomings can be significantly improved by incorporating a fine-cell foam structure in the composites. This thesis presents the development of the foaming technology for the manufacture of fine-cell WPC foams with environmentally benign physical blowing agents (PBAs), and focuses on the elucidation of the fundamental foaming mechanisms and the related issues involved. One critical issue comes from the volatiles evolved from the wood-fiber during high temperature processing. The volatiles, as a blowing agent, can contribute to the foaming process. However, they lead to gross deterioration of the cell structure of WPC foams. The presence of volatiles makes foaming of WPC "a poorly understood black art". With the use of PBAs, a strategy of lowering processing temperature becomes feasible, to suppress the generation of volatiles. A series of PBA-based experiments were designed using a statistical design of experiments (DOE) technique, and were performed to establish the relationship of processing and material variables with the structure of WPC foams. Fundamental foaming behaviors for two different PBAs and two different polymer systems were identified. WPC foams with a fine-cell morphology and a desired density were successfully obtained at the optimized conditions. Another limitation for the wider application of WPC is their flammability. Innovative use of a small amount of nano-clay in WPC significantly improved the flame-retarding property of WPC, and the key issue was to achieve a high degree of exfoliation of nano-particles in the polymer matrix, to achieve a desired flammability reduction. The synergistic effects of nano-particles in foaming of WPC were

Evaluation of polyacrylonitrile electrospun nano-fibrous mats as leukocyte removal filter media.

PubMed

Pourbaghi, Raha; Zarrebini, Mohammad; Semnani, Dariush; Pourazar, Abbasali; Akbari, Nahid; Shamsfar, Reihaneh

2018-07-01

Removal of leukocytes from blood products is the most effective means for elimination of undesirable side effects and prevention of possible reactions in recipients. Micro-fibrous mats are currently used for removal of leukocytes from blood. In this study, samples of electrospun nano-fibrous mats were produced. The performance of the produced electrospun nano-fibrous mats as means of leukocytes removal from fresh whole blood was both evaluated and compared with that of commercially available micro-fibrous mats. In order to produce the samples, polyacrylonitrile (PAN) nano-fibrous mats were made under different electrospinning conditions. Mean fiber diameter, pore characterization and surface roughness of the PAN nano-fibrous mats were determined using image processing technique. In order to evaluate the surface tension of the fabricated mats, water contact angle was measured. The leukocyte removal performance, erythrocytes recovery percent and hemolysis rate of the nano-fibrous mats were compared. The effectiveness of nano-fibrous mats in removing leukocyte was established using both scanning electron microscope and optical microscope. Results showed that for given weight, the fabricated nano-fibrous mats were not only more efficient but also more cost-effective than their commercial counterparts. Results confirmed that changes in mean fiber diameter, the number of layer and weight of each layer in the absence of any chemical reaction or physical surface modification, the fabricated nano-fibrous mats were able to remove 5-log of leukocytes. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1759-1769, 2018. © 2017 Wiley Periodicals, Inc.

Antibacterial performance of nano polypropylene filter media containing nano-TiO2 and clay particles

NASA Astrophysics Data System (ADS)

Shafiee, Sara; Zarrebini, Mohammad; Naghashzargar, Elham; Semnani, Dariush

2015-10-01

Disinfection and elimination of pathogenic microorganisms from liquid can be achieved by filtration process using antibacterial filter media. The advent of nanotechnology has facilitated the introduction of membranes consisting of nano-fiber in filtration operations. The melt electro-spun fibers due to their extremely small diameters are used in the production of this particular filtration medium. In this work, antibacterial polypropylene filter medium containing clay particles and nano-TiO2 were made using melt electro-spun technology. Antibacterial performance of polypropylene nano-filters was evaluated using E. coli bacteria. Additionally, filtration efficiency of the samples in terms fiber diameter, filter porosity, and fiber distribution using image processing technique was determined. Air permeability and dust aerosol tests were conducted to establish the suitability of the samples as a filter medium. It was concluded that as far as antibacterial property is concerned, nano-fibers filter media containing clay particles are preferential to similar media containing TiO2 nanoparticles.

Production of ultra-thin nano-scaled graphene platelets from meso-carbon micro-beads

DOEpatents

Zhamu, Aruna; Guo, Jiusheng; Jang, Bor Z

2014-11-11

A method of producing nano-scaled graphene platelets (NGPs) having an average thickness no greater than 50 nm, typically less than 2 nm, and, in many cases, no greater than 1 nm. The method comprises (a) intercalating a supply of meso-carbon microbeads (MCMBs) to produce intercalated MCMBs; and (b) exfoliating the intercalated MCMBs at a temperature and a pressure for a sufficient period of time to produce the desired NGPs. Optionally, the exfoliated product may be subjected to a mechanical shearing treatment, such as air milling, air jet milling, ball milling, pressurized fluid milling, rotating-blade grinding, or ultrasonicating. The NGPs are excellent reinforcement fillers for a range of matrix materials to produce nanocomposites. Nano-scaled graphene platelets are much lower-cost alternatives to carbon nano-tubes or carbon nano-fibers.

Feasibility of producing cast-refractory metal-fiber superalloy composites

NASA Technical Reports Server (NTRS)

Mcintyre, R. D.

1973-01-01

A study was conducted to evaluate the feasibility of direct casting as a practical method for producing cast superalloy tungsten or columbium alloy fiber composites while retaining a high percentage of fiber strength. Fourteen nickel base, four cobalt, and three iron based matrices were surveyed for their degree of reaction with the metal fibers. Some stress-rupture results were obtained at temperatures of 760, 816, 871, and 1093 C for a few composite systems. The feasibility of producing acceptable composites of some cast nickel, cobalt, and iron matrix alloys with tungsten or columbium alloy fibers was demonstrated.

Effect of nano-SiO{sub 2} particles and curing time on development of fiber-matrix bond properties and microstructure of ultra-high strength concrete

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Zemei; Department of Civil, Architectural and Environmental Engineering, Missouri University of Science and Technology, Rolla 65409, MO; Khayat, Kamal Henri, E-mail: khayatk@mst.edu

Bond properties between fibers and cementitious matrix have significant effect on the mechanical behavior of composite materials. In this study, the development of steel fiber-matrix interfacial bond properties in ultra-high strength concrete (UHSC) proportioned with nano-SiO{sub 2} varying between 0 and 2%, by mass of cementitious materials, was investigated. A statistical model relating either bond strength or pullout energy to curing time and nano-SiO{sub 2} content was proposed by using the response surface methodology. Mercury intrusion porosimetry (MIP) and backscatter scanning electron microscopy (BSEM) were used to characterize the microstructure of the matrix and the fiber-matrix interface, respectively. Micro-hardness aroundmore » the embedded fiber and hydration products of the matrix were evaluated as well. Test results indicated that the optimal nano-SiO{sub 2} dosage was 1% in terms of the bond properties and the microstructure. The proposed quadratic model efficiently predicted the bond strength and pullout energy with consideration of curing time and nano-SiO{sub 2} content. The improvement in bond properties associated with nano-silica was correlated with denser matrix and/or interface and stronger bond and greater strength of hydration products based on microstructural analysis.« less

Method of producing a hybrid matrix fiber composite

DOEpatents

Deteresa, Steven J [Livermore, CA; Lyon, Richard E [Absecon, NJ; Groves, Scott E [Brentwood, CA

2006-03-28

Hybrid matrix fiber composites having enhanced compressive performance as well as enhanced stiffness, toughness and durability suitable for compression-critical applications. The methods for producing the fiber composites using matrix hybridization. The hybrid matrix fiber composites comprised of two chemically or physically bonded matrix materials, whereas the first matrix materials are used to impregnate multi-filament fibers formed into ribbons and the second matrix material is placed around and between the fiber ribbons that are impregnated with the first matrix material and both matrix materials are cured and solidified.

System to continuously produce carbon fiber via microwave assisted plasma processing

DOEpatents

White, Terry L [Knoxville, TN; Paulauskas, Felix L [Knoxville, TN; Bigelow, Timothy S [Knoxville, TN

2010-11-02

A system to continuously produce fully carbonized or graphitized carbon fibers using microwave-assisted plasma (MAP) processing comprises an elongated chamber in which a microwave plasma is excited in a selected gas atmosphere. Fiber is drawn continuously through the chamber, entering and exiting through openings designed to minimize in-leakage of air. There is a gradient of microwave power within the chamber with generally higher power near where the fiber exits and lower power near where the fiber enters. Polyacrylonitrile (PAN), pitch, or any other suitable organic/polymeric precursor fibers can be used as a feedstock for the inventive system. Oxidized or partially oxidized PAN or pitch or other polymeric fiber precursors are run continuously through a MAP reactor in an inert, non-oxidizing atmosphere to heat the fibers, drive off the unwanted elements such as oxygen, nitrogen, and hydrogen, and produce carbon or graphite fibers faster than conventionally produced carbon fibers.

Nano-cone optical fiber array sensors for MiRNA profiling

NASA Astrophysics Data System (ADS)

Wang, Yunshan; Senapati, Satyajyoti; Stoddart, Paul; Howard, Scott; Chang, Hsueh-Chia

2013-09-01

Up/down regulation of microRNA panels has been correlated to cardiovascular diseases and cancer. Frequent miRNA profiling at home can hence allow early cancer diagnosis and home-use chronic disease monitoring, thus reducing both mortality rate and healthcare cost. However, lifetime of miRNAs is less than 1 hour without preservation and their concentrations range from pM to mM. Despite rapid progress in the last decade, modern nucleic acid analysis methods still do not allow personalized miRNA profiling---Real-time PCR and DNA micro-array both require elaborate miRNA preservation steps and expensive equipment and nano pore sensors cannot selectively quantify a large panel with a large dynamic range. We report a novel and low-cost optical fiber sensing platform, which has the potential to profile a panel of miRNA with simple LED light sources and detectors. The individual tips of an optical imaging fiber bundle (mm in diameter with 7000 fiber cores) were etched into cones with 10 nm radius of curvature and coated with Au. FRET (Forster Resonant Energy Transfer) hairpin oligo probes, with the loop complementary to a specific miRNA that can release the hairpin, were functionalized onto the conic tips. Exciting light in the optical fiber waveguide is optimally coupled to surface plasmonics on the gold surface, which then converges to the conic tips with two orders of magnitude enhancement in intensity. Unlike nanoparticle plasmonics, tip plasmonics can be excited over a large band width and hence the plasmonic enhanced fluorescence signal of the FRET reporter is also focused towards the tip--- and is further enhanced with the periodic resonant grid of the fiber array which gives rise to pronounced standing wave interference patterns. Multiplexing is realized by functionalizing different probes onto one fiber bundle using a photoactivation process.

Methods for producing and using densified biomass products containing pretreated biomass fibers

DOEpatents

Dale, Bruce E.; Ritchie, Bryan; Marshall, Derek

2015-05-26

A process is provided comprising subjecting a quantity of plant biomass fibers to a pretreatment to cause at least a portion of lignin contained within each fiber to move to an outer surface of said fiber, wherein a quantity of pretreated tacky plant biomass fibers is produced; and densifying the quantity of pretreated tacky plant biomass fibers to produce one or more densified biomass particulates, wherein said biomass fibers are densified without using added binder.

Achieving Higher Strength and Sensitivity toward UV Light in Multifunctional Composites by Controlling the Thickness of Nano-Layer on the Surface of Glass Fiber.

PubMed

Sun, Chao; Zhang, Jie; Gao, Shanglin; Zhang, Nan; Zhang, Yijun; Zhuang, Jian; Liu, Ming; Zhang, Xiaohui; Ren, Wei; Wu, Hua; Ye, Zuo-Guang

2018-06-18

The interphase between fiber and matrix plays an essential role in the performance of composites. Therefore, the ability to design or modify the interphase is a key technology needed to manufacture stronger and smarter composite. Recently, depositing nano-materials onto the surface of the fiber has become a promising approach to optimize the interphase and composites. But, the modified composites have not reached the highest strength yet, because the determining parameters, such as thickness of the nano-layer, are hardly controlled by the mentioned methods in reported works. Here, we deposit conformal ZnO nano-layer with various thicknesses onto the surfaces of glass fibers via the atomic layer deposition (ALD) method and a tremendous enhancement of interfacial shear strength of composites is achieved. Importantly, a critical thickness of ZnO nano-layer is obtained for the first time, giving rise to a maximal relative enhancement in the interfacial strength, which is more than 200% of the control fiber. In addition, the single modified fiber exhibits a potential application as a flexible, transparent, in-situ UV detector in composites. And, we find the UV-sensitivity also shows a strong correlation with the thickness of ZnO. To reveal the dependence of UV-sensitivity on thickness, a depletion thickness is estimated by a proposed model which is an essential guide to design the detectors with higher sensitivity. Consequently, such precise tailoring of the interphase offers an advanced way to improve and to flexibly control various macroscopic properties of multifunctional composites of the next generation.

Integrated production of nano-fibrillated cellulose and cellulosic biofuel (ethanol) by enzymatic fractionation of wood fibers

Treesearch

Junyong Zhu; Ronald Sabo; Xiaolin Luo

2011-01-01

This study demonstrates the feasibility of integrating the production of nano-fibrillated cellulose (NFC), a potentially highly valuable biomaterial, with sugar/biofuel (ethanol) from wood fibers. Commercial cellulase enzymes were used to fractionate the less recalcitrant amorphous cellulose from a bleached Kraft eucalyptus pulp, resulting in a highly crystalline and...

Nano-structured calcite produced by micro-organisms in ancient and modern loess in Chinese Loess Plateau

NASA Astrophysics Data System (ADS)

Xu, H.; Chen, T.; Lu, H.; Wang, X.

2005-12-01

The results from transmission electron microscopy (TEM) and field emission gun scanning microscopy (FEG-SEM) investigation show that there are calcite nano-fibers (CNFs) formed during pedogenic process. The CNFs are widely distributed in the loess and red clay samples of Caoxian, Luochuan, Lingtai, Lantian, and Xifeng profiles as well as the samples of modern surface loess soils in Chinese Loess Plateau. Diameters of all the NFCs are about 40 nm, the length of the CNFs ranges from tens nanometer to several micrometers. Elongation direction of NFCs is unusual near parallel (105)* or (115)*. Crystals of NFCs arrange as bird net like and lattice-like frameworks. X-ray EDS spectra show the weak peaks of magnesium, phosphorous, and sulfur. Our investigation indicates that CNFs are in pore space of loess and paleosol and made up most of carbonate except for caliche nodular layers. Concentration of NFCs in the loess layers are significantly higher than those of paleosol layers because of leaching of carbonate in the paleosol forming environment (warn and wet paleoclimate). The "nanobacteria-like CNFs are well crystalline calcite single crystals with smoothes surfaces. The morphologies of CNFs are very unusual and different from the calcite single crystals observed in most geological environments. The CNFs are directly related to microbial activities in both ancient and modern loess. It is proposed that the intervention of organic compounds derived from microbial activities control the formation of the calcite nano-fibers. Both morphology and bulk composition of CNFs indicate that the formation of the CNFs involves bio-organics derived from microorganisms in loess deposit environment. Formation conditions of the calcite nano-fibers may information about paleoclimate, paleo-environment and paleoecology. So, the discovery of CNFs in loess-paloesol sequences can provide a new route for reconstruct paleoclimate by oxygen and carbon isotope from the CNFs.

Chromium doped nano-phase separated yttria-alumina-silica glass based optical fiber preform: fabrication and characterization

NASA Astrophysics Data System (ADS)

Dutta, Debjit; Dhar, Anirban; Das, Shyamal; Bysakh, Sandip; Kir'yanov, Alexandar; Paul, Mukul Chandra

2015-06-01

Transition metal (TM) doping in silica core optical fiber is one of the research area which has been studied for long time and Chromium (Cr) doping specially attracts a lot of research interest due to their broad emission band covering U, C and L band with many potential application such as saturable absorber or broadband amplifier etc. This paper present fabrication of Cr doped nano-phase separated silica fiber within yttria-alumina-silica core glass through conventional Modified Chemical Vapor Deposition (MCVD) process coupled with solution doping technique along with different material and optical characterization. For the first time scanning electron microscope (SEM) / energy dispersive X-ray (EDX) analysis of porous soot sample and final preform has been utilized to investigate incorporation mechanism of Crions with special emphasis on Cr-species evaporation at different stages of fabrication. We also report that optimized annealing condition of our fabricated preform exhibited enhanced fluorescence emission and a broad band within 550- 800 nm wavelength region under pumping at 532 nm wavelength due to nano-phase restructuration.

Polymer fiber-based models of connective tissue repair and healing.

PubMed

Lee, Nancy M; Erisken, Cevat; Iskratsch, Thomas; Sheetz, Michael; Levine, William N; Lu, Helen H

2017-01-01

Physiologically relevant models of wound healing are essential for understanding the biology of connective tissue repair and healing. They can also be used to identify key cellular processes and matrix characteristics critical for the design of soft tissue grafts. Modeling the various stages of repair post tendon injury, polymer meshes of varying fiber diameter (nano-1 (390 nm) < nano-2 (740 nm) < micro (1420 nm)) were produced. Alignment was also introduced in the nano-2 group to model matrix undergoing biological healing rather than scar formation. The response of human tendon fibroblasts on these model substrates were evaluated over time as a function of fiber diameter and alignment. It was observed that the repair models of unaligned nanoscale fibers enhanced cell growth and collagen synthesis, while these outcomes were significantly reduced in the mature repair model consisting of unaligned micron-sized fibers. Organization of paxillin and actin on unaligned meshes was enhanced on micro- compared to nano-sized fibers, while the expression and activity of RhoA and Rac1 were greater on nanofibers. In contrast, aligned nanofibers promoted early cell organization, while reducing excessive cell growth and collagen production in the long term. These results show that the early-stage repair model of unaligned nanoscale fibers elicits a response characteristic of the proliferative phase of wound repair, while the more mature model consisting of unaligned micron-sized fibers is more representative of the remodeling phase by supporting cell organization while suppressing growth and biosynthesis. Interestingly, introduction of fiber alignment in the nanofiber model alters fibroblast response from repair to healing, implicating matrix alignment as a critical design factor for circumventing scar formation and promoting biological healing of soft tissue injuries. Copyright © 2016 Elsevier Ltd. All rights reserved.

Label-free tracking of single extracellular vesicles in a nano-fluidic optical fiber (Conference Presentation)

NASA Astrophysics Data System (ADS)

van der Pol, Edwin; Weidlich, Stefan; Lahini, Yoav; Coumans, Frank A. W.; Sturk, Auguste; Nieuwland, Rienk; Schmidt, Markus A.; Faez, Sanli; van Leeuwen, Ton G.

2016-03-01

Background: Extracellular vesicles, such as exosomes, are abundantly present in human body fluids. Since the size, concentration and composition of these vesicles change during disease, vesicles have promising clinical applications, including cancer diagnosis. However, since ~70% of the vesicles have a diameter <70 nm, detection of single vesicles remains challenging. Thus far, vesicles <70 nm have only be studied by techniques that require the vesicles to be adhered to a surface. Consequently, the majority of vesicles have never been studied in their physiological environment. We present a novel label-free optical technique to track single vesicles <70 nm in suspension. Method: Urinary vesicles were contained within a single-mode light-guiding silica fiber containing a 600 nm nano-fluidic channel. Light from a diode laser (660 nm wavelength) was coupled to the fiber, resulting in a strongly confined optical mode in the nano-fluidic channel, which continuously illuminated the freely diffusing vesicles inside the channel. The elastic light scattering from the vesicles, in the direction orthogonal to the fiber axis, was collected using a microscope objective (NA=0.95) and imaged with a home-built microscope. Results: We have tracked single urinary vesicles as small as 35 nm by elastic light scattering. Please note that vesicles are low-refractive index (n<1.4) particles, which we confirmed by combining data on thermal diffusion and light scattering cross section. Conclusions: For the first time, we have studied vesicles <70 nm freely diffusing in suspension. The ease-of-use and performance of this technique support its potential for vesicle-based clinical applications.

Electron tomography and nano-diffraction enabling the investigation of individual magnetic nanoparticles inside fibers of MR visible implants

NASA Astrophysics Data System (ADS)

Slabu, I.; Wirch, N.; Caumanns, T.; Theissmann, R.; Krüger, M.; Schmitz-Rode, T.; Weirich, T. E.

2017-08-01

Superparamagnetic iron oxide nanoparticles (SPIONPs) incorporated into the base material of implants are used as contrast agents in magnetic resonance imaging for the delineation of the implants from the surrounding tissue. However, the delineation quality is strongly related to the structural characteristics of the incorporated SPIONPs and their interparticle interaction as well as their interaction with the polymer matrix of the implant. Consequently, a profound knowledge of the formation of aggregates inside the polymer matrix, which are responsible for strong interparticle interactions, and of their structural characteristics, is required for controlling the magnetic resonance image quality of the implants. In this work, transmission electron microscopy methods such as electron tomography and nano-electron diffraction were used to depict SPIONP aggregates inside the melt-spin polyvinylidene fluoride fibers used for the assembly of implants and to determine the crystal structure of individual nanocrystals inside these aggregates, respectively. Using these techniques it was possible for the first time to characterize the aggregates inside the fibers of implants and to validate the magnetization measurements that have been previously used to assess the interaction phenomena inside the fibers of implants. With electron tomography, inhomogeneously sized distributed aggregates were delineated and 3D models of these aggregates were constructed. Furthermore, the distribution of the aggregates inside the fibers was verified by means of magnetic force microscopy. With nano-diffraction measurements, the SPIONP crystal structure inside the fibers of the implant could not be clearly assigned to that of magnetite (Fe3O4) or maghemite (γ-Fe2O3). Therefore, additional electron energy loss spectroscopy measurements were performed, which revealed the presence of both phases of Fe3O4 and γ-Fe2O3, probably caused by oxidation processes during the manufacture of the fibers by

Controllable preparation of a nano-hydroxyapatite coating on carbon fibers by electrochemical deposition and chemical treatment.

PubMed

Wang, Xudong; Zhao, Xueni; Wang, Wanying; Zhang, Jing; Zhang, Li; He, Fuzhen; Yang, Jianjun

2016-06-01

A nano-hydroxyapatite (HA) coating with appropriate thickness and morphology similar to that of human bone tissue was directly prepared onto the surfaces of carbon fibers (CFs). A mixed solution of nitric acid, hydrochloric acid, sulfuric acid, and hydrogen peroxide (NHSH) was used in the preparation process. The coating was fabricated by combining NHSH treatment and electrochemical deposition (ECD). NHSH treatment is easy to operate, produces rapid reaction, and highly effective. This method was first used to induce the nucleation and growth of HA crystals on the CF surfaces. Numerous O-containing functional groups, such as hydroxyl (-OH) and carboxyl (-COOH) groups, were grafted onto the CF surfaces by NHSH treatment (NHSH-CFs); as such, the amounts of these groups on the functionalized CFs increased by nearly 8- and 12-fold, respectively, compared with those on untreated CFs. After treatment, the NHSH-CFs not only acquired larger specific surface areas but retained surfaces free from serious corrosion or breakage. Hence, NHSH-CFs are ideal depositional substrates of HA coating during ECD. ECD was successfully used to prepare a nano-rod-like HA coating on the NHSH-CF surfaces. The elemental composition, structure, and morphology of the HA coating were effectively controlled by adjusting various technological parameters, such as the current density, deposition time, and temperature. The average central diameter of HA crystals and the coating density increased with increasing deposition time. The average central diameter of most HA crystals on the NHSH-CFs varied from approximately 60 nm to 210 nm as the deposition time increased from 60 min to 180 min. Further studies on a possible deposition mechanism revealed that numerous O-containing functional groups on the NHSH-CF surfaces could associate with electrolyte ions (Ca(2+)) to form special chemical bonds. These bonds can induce HA coating deposition and improve the interfacial bonding strength between the HA

Silk/nano-material hybrid: properties and functions

NASA Astrophysics Data System (ADS)

Steven, Eden; Lebedev, Victor; Laukhina, Elena; Laukhin, Vladimir; Alamo, Rufina G.; Rovira, Concepcio; Veciana, Jaume; Brooks, James S.

2014-03-01

Silk continues to emerge as a material of interest in electronics. In this work, the interaction between silk and conducting nano-materials are investigated. Simple fabrication methods, physical, electronic, thermal, and actuation properties are reported for spider silk / carbon nanotube (CNT-SS) and Bombyx mori / (BEDT-TTF)-based organic molecular conductor hybrids (ET-S). The CNT-SS fibers are produced via water and shear assisted method, resulting in fibers that are tough, custom-shapeable, flexible, and electrically conducting. For ET-S bilayer films, a layer transfer technique is developed to deposit linked crystallites of (BEDT-TTF)2I3 molecular conductor onto silk films, generating highly piezoresistive semi-transparent films. In both cases, the hybridization allows us to gain additional functions by harnessing the water-dependent properties of silk materials, for example, as humidity sensor and electrical current- or water-driven actuators. SEM, TEM, FT-IR, and resistance measurements under varying temperature, strain, and relative humidity reveal the synergistic interactions between the bio- and nano-materials. E.S. is supported by NSF-DMR 1005293.

Nano-yttria dispersed stainless steel composites composed by the 3 dimensional fiber deposition technique

NASA Astrophysics Data System (ADS)

Verhiest, K.; Mullens, S.; De Wispelaere, N.; Claessens, S.; DeBremaecker, A.; Verbeken, K.

2012-09-01

In this study, oxide dispersion strengthened (ODS) 316L steel samples were manufactured by the 3 dimensional fiber deposition (3DFD) technique. The performance of 3DFD as colloidal consolidation technique to obtain porous green bodies based on yttria (Y2O3) nano-slurries or paste, is discussed within this experimental work. The influence of the sintering temperature and time on sample densification and grain growth was investigated in this study. Hot consolidation was performed to obtain final product quality in terms of residual porosity reduction and final dispersion homogeneity.

Titanium-Dioxide Nano-Fiber-Cotton Targets for Efficient Multi-keV X-Ray Generation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tanabe, M; Nishimura, H; Fujioka, S

Multi-keV x-ray generation from low-density (27 {+-} 7 mg/cc) nano-fiber-cotton targets composed of titanium-dioxide has been investigated. The cotton targets were heated volumetrically and supersonically to a peak electron temperature of 2.3 keV, which is optimal to yield Ti K-shell x rays. Considerable enhancement of conversion efficiency (3.7 {+-} 0.5%) from incident laser energy into Ti K-shell x rays (4-6 keV band) was attained in comparison with that (1.4 {+-} 0.9%) for a planar Ti-foil target.

Red light emitting nano-PVP fibers that hybrid with Ag@SiO2@Eu(tta)3phen-NPs by electrostatic spinning method

NASA Astrophysics Data System (ADS)

Zhang, Xiaolin; Tang, Jianguo; Li, Haidong; Wang, Yao; Wang, Xinzhi; Wang, Yanxin; Huang, Linjun; Belfiore, Laurence A.

2018-04-01

This work demonstrated red light emitting nano-PVP fibers that incorporated with novel three-layer nanostructure of Ag@SiO2@Eu(tta)3phen nanoparticles (Ag@SiO2@Eu(tta)3phen-NPs), and the hybrid nano-PVP fibers were fabricated via a remarkably simple electrostatic spinning method. For Ag@SiO2@Eu(tta)3phen-NPs, the thickness of SiO2 is optimized to obtain the maximum luminescent intensity, as results, the optimized thickness of SiO2 is 20 nm. And the corresponding luminescent intensity (612 nm) of the Ag@SiO2@Eu(tta)3phen-NPs is enhanced up to 10 times compared with the pure Eu(tta)3phen complex, which indicates that with 20 nm SiO2 thickness, the localized surface plasmon resonance (LSPR) effect of Ag@SiO2 exhibits highest performance for enhancing luminescence. Moreover, the luminescent PVP fibers emit bright red light under the fluorescence microscope, which definitely confirms that the microenvironment provided by PVP polymer is absolutely suitable for the fluorescent composites.

Recent Progress in Producing Lignin-Based Carbon Fibers for Functional Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Paul, Ryan; Burwell, Deanna; Dai, Xuliang

Lignin, a biopolymer, has been investigated as a renewable and low-cost carbon fiber precursor since the 1960s. Although successful lab-scale production of lignin-based carbon fibers has been reported, there are currently not any commercial producers. This paper will highlight some of the known challenges with converting lignin-based precursors into carbon fiber, and the reported methods for purifying and modifying lignin to improve it as a precursor. Several of the challenges with lignin are related to its diversity in chemical structure and purity, depending on its biomass source (e.g. hardwood, softwood, grasses) and extraction method (e.g. organosolv, kraft). In order tomore » make progress in this field, GrafTech and Oak Ridge National Laboratory are collaborating to develop lignin-based carbon fiber technology and to demonstrate it in functional applications, as part of a cooperative agreement with the DOE Advanced Manufacturing Office. The progress made to date with producing lignin-based carbon fiber for functional applications, as well as developing and qualifying a supply chain and value proposition, are also highlighted.« less

Nanoscale analysis of degradation processes of cellulose fibers.

PubMed

Teodonio, Lorenzo; Missori, Mauro; Pawcenis, Dominika; Łojewska, Joanna; Valle, Francesco

2016-12-01

Mapping the morphological and nano-mechanical properties of cellulose fibers within paper sheets or textile products at the nano-scale level by using atomic force microscopy is a challenging task due to the huge surface level variation of these materials. However this task is fundamental for applications in forensic or cultural heritage sciences and for the industrial characterization of materials. In order to correlate between nano-mechanical properties and local nanometer scale morphology of different layers of cellulose fibers, a new strategy to prepare samples of isolated cellulose fibers was designed. This approach is based on immobilizing isolated fibers onto glass slides chemically pretreated so as to promote cellulose adhesion. The experiments presented here aim at the nano-scale characterization of fibers in paper samples aged under different external agents (relative humidity, temperature) in such a way as to promote hydrolysis and oxidation of polymers. The observed variability of local mechanical properties of paper fibers was related to varying degrees of cellulose polymerization induced by artificial aging. Copyright © 2016 Elsevier Ltd. All rights reserved.

In vitro study of improved wound-healing effect of bioactive borate-based glass nano-/micro-fibers.

PubMed

Yang, Qingbo; Chen, Sisi; Shi, Honglan; Xiao, Hai; Ma, Yinfa

2015-10-01

Because of the promising wound-healing capability, bioactive glasses have been considered as one of the next generation hard- and soft-tissue regeneration materials. The lack of understanding of the substantial mechanisms, however, indicates the need for further study on cell-glass interactions to better interpret the rehabilitation capability. In the present work, three bioactive glass nano-/micro-fibers, silicate-based 45S5, borate-based 13-93B3 and 1605 (additionally doped with copper oxide and zinc oxide), were firstly compared for their in vitro soaking/conversion rate. The results of elemental monitoring and electron microscopic characterization demonstrated that quicker ion releasing and glass conversion occurred in borate-based fibers than that of silicate-based one. This result was also reflected by the formation speed of hydroxyapatite (HA). This process was further correlated with original boron content and surrounding rheological condition. We showed that an optimal fiber pre-soaking time (or an ideal dynamic flow rate) should exist to stimulate the best cell proliferation and migration ability. Moreover, 13-93B3 and 1605 fibers showed different glass conversion and biocompatibility properties as well, indicating that trace amount variation in composition can also influence fiber's bioactivity. In sum, our in vitro rheological module closely simulated in vivo niche environment and proved a potentially improved wound-healing effect by borate-based glass fibers, and the results shall cast light on future improvement in bioactive glass fabrication. Copyright © 2015 Elsevier B.V. All rights reserved.

The nature of nano-sized precipitates in ferritic/martensitic steel P92 produced by thermomechanical treatment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shen, Yinzhong, E-mail: shenyz@sjtu.edu.cn

Thermomechanical treatment (TMT) can effectively improve the mechanical properties of high-Cr ferritic/martensitic (F/M) steels, which has been mainly attributed to a dense dispersion of nano-sized precipitates. Precipitate phases in high-Cr F/M steels produced by TMT require further investigations. Precipitates in commercial F/M steel P92 produced by a TMT process, warm-rolled at 650 °C plus tempered at 650 °C for 1 h, were investigated by transmission electron microscopy. Nano-sized precipitates with a high number density in the steel after the TMT were found to be Cr-rich M{sub 2}(C,N) carbonitride, rather than MX or M{sub 23}C{sub 6} phase. The M{sub 2}(C,N) carbonitridemore » has a hexagonal lattice with the lattice parameters about a/c = 0.299/0.463 nm. These M{sub 2}(C,N) carbonitrides with a typical composition of (Cr{sub 0.85}V{sub 0.06}Fe{sub 0.06}Mo{sub 0.03}){sub 2}(C,N) have an average diameter smaller than 30 nm, and mainly distribute on dislocations and at the boundaries of equiaxed ferrite grains in the TMT steel. The TMT process inhibits the precipitation of M{sub 23}C{sub 6} and M{sub 5}C{sub 2} phases. Enhanced creep properties of the P92 steel after the TMT, as reported previously, were considered to be mainly attributed to plenty of nano-sized Cr-rich M{sub 2}(C,N) carbonitrides produced by the TMT rather than to MX and M{sub 23}C{sub 6} precipitates. - Graphical abstract: TEM micrographs of precipitates on extraction carbon replicas prepared from ferritic/martensitic (F/M) steel P92. (a) After conventional heat treatment, normalized at 1050 °C for 30 min plus tempered at 765 °C for 1 h. (b) After a thermomechanical treatment (TMT), warm-rolled at 650 °C plus tempered at 650 °C for 1 h. Nano-sized precipitates with a high number density in the steel produced by the TMT were found to be Cr-rich M{sub 2}(C,N) carbonitride, rather than MX or M{sub 23}C{sub 6} phase. The TMT process inhibits the precipitation of M{sub 23}C{sub 6} and M

Method of producing superconducting fibers of YBA2CU30X

DOEpatents

Schwartzkopf, Louis A.; Ostenson, Jerome E.; Finnemore, Douglas K.

1990-11-13

Fibers of YBa.sub.2 Cu.sub.3 O.sub.x have been produce by pendant drop melt extraction. This technique involves the end of a rod of YBa.sub.2 Cu.sub.3 O.sub.x melted with a hydrogen-oxygen torch, followed by lowering onto the edge of a spinning wheel. The fibers are up to 10 cm in length with the usual lateral dimensions, ranging from 20 .mu.m to 125 .mu.m. The fibers require a heat treatment to make them superconducting.

Mixture for producing fracture-resistant, fiber-reinforced ceramic material by microwave heating

DOEpatents

Meek, T.T.; Blake, R.D.

1985-04-03

A fracture-resistant, fiber-reinforced ceramic substrate is produced by a method which involves preparing a ceramic precursor mixture comprising glass material, a coupling agent, and resilient fibers, and then exposing the mixture to microwave energy. The microwave field orients the fibers in the resulting ceramic material in a desired pattern wherein heat later generated in or on the substrate can be dissipated in a desired geometric pattern parallel to the fiber pattern. Additionally, the shunt capacitance of the fracture-resistant, fiber-reinforced ceramic substrate is lower which provides for a quicker transit time for electronic pulses in any conducting pathway etched into the ceramic substrate.

Mixture for producing fracture-resistant, fiber-reinforced ceramic material by microwave heating

DOEpatents

Meek, T.T.; Blake, R.D.

1987-09-22

A fracture-resistant, fiber-reinforced ceramic substrate is produced by a method which involves preparing a ceramic precursor mixture comprising glass material, a coupling agent, and resilient fibers, and then exposing the mixture to microwave energy. The microwave field orients the fibers in the resulting ceramic material in a desired pattern wherein heat later generated in or on the substrate can be dissipated in a desired geometric pattern parallel to the fiber pattern. Additionally, the shunt capacitance of the fracture-resistant, fiber-reinforced ceramic substrate is lower which provides for a quicker transit time for electronic pulses in any conducting pathway etched into the ceramic substrate. 2 figs.

Mixture for producing fracture-resistant, fiber-reinforced ceramic material by microwave heating

DOEpatents

Meek, Thomas T.; Blake, Rodger D.

1987-01-01

A fracture-resistant, fiber-reinforced ceramic substrate is produced by a method which involves preparing a ceramic precursor mixture comprising glass material, a coupling agent, and resilient fibers, and then exposing the mixture to microwave energy. The microwave field orients the fibers in the resulting ceramic material in a desired pattern wherein heat later generated in or on the substrate can be dissipated in a desired geometric pattern parallel to the fiber pattern. Additionally, the shunt capacitance of the fracture-resistant, fiber-reinforced ceramic substrate is lower which provides for a quicker transit time for electronic pulses in any conducting pathway etched into the ceramic substrate.

Method of producing a ceramic fiber-reinforced glass-ceramic matrix composite

NASA Technical Reports Server (NTRS)

Bansal, Narottam P. (Inventor)

1994-01-01

A fiber-reinforced composite composed of a BaO-Al2O3-2SiO2 (BAS) glass ceramic matrix is reinforced with CVD silicon carbide continuous fibers. A slurry of BAS glass powders is prepared and celsian seeds are added during ball melting. The slurry is cast into tapes which are cut to the proper size. Continuous CVD-SiC fibers are formed into mats of the desired size. The matrix tapes and the fiber mats are alternately stacked in the proper orientation. This tape-mat stack is warm pressed to produce a 'green' composite. The 'green' composite is then heated to an elevated temperature to burn out organic constituents. The remaining interim material is then hot pressed to form a silicon carbide fiber-reinforced celsian (BAS) glass-ceramic matrix composite which may be machined to size.

Comparison on exfoliated graphene nano-sheets and triturated graphite nano-particles for mode-locking the Erbium-doped fibre lasers

NASA Astrophysics Data System (ADS)

Yang, Chun-Yu; Lin, Yung-Hsiang; Wu, Chung-Lun; Cheng, Chih-Hsien; Tsai, Din-Ping; Lin, Gong-Ru

2018-06-01

Comparisons on exfoliated graphene nano-sheets and triturated graphite nano-particles for mode-locking the Erbium-doped fiber lasers (EDFLs) are performed. As opposed to the graphite nano-particles obtained by physically triturating the graphite foil, the tri-layer graphene nano-sheets is obtained by electrochemically exfoliating the graphite foil. To precisely control the size dispersion and the layer number of the exfoliated graphene nano-sheet, both the bias of electrochemical exfoliation and the speed of centrifugation are optimized. Under a threshold exfoliation bias of 3 volts and a centrifugation at 1000 rpm, graphene nano-sheets with an average diameter of 100  ±  40 nm can be obtained. The graphene nano-sheets with an area density of 15 #/µm2 are directly imprinted onto the end-face of a single-mode fiber made patchcord connector inside the EDFL cavity. Such electrochemically exfoliated graphene nano-sheets show comparable saturable absorption with standard single-graphene and perform the self-amplitude modulation better than physically triturated graphite nano-particles. The linear transmittance and modulation depth of the inserted graphene nano-sheets are 92.5% and 53%, respectively. Under the operation with a power gain of 21.5 dB, the EDFL can be passively mode-locked to deliver a pulsewidth of 454.5 fs with a spectral linewidth of 5.6 nm. The time-bandwidth product of 0.31 is close to the transform limit. The Kelly sideband frequency spacing of 1.34 THz is used to calculate the chirp coefficient as  ‑0.0015.

Effect of graphene oxide nano filler on dynamic behaviour of GFRP composites

NASA Astrophysics Data System (ADS)

Pujar, Nagabhushan V.; Nanjundaradhya, N. V.; Sharma, Ramesh S.

2018-04-01

Nano fillers like Alumina oxide, Titanium oxide, Carbon nano tube, Nano clay have been used to improve the mechanical and damping properties of fiber reinforced polymer composites. In the recent years Graphene oxide nano filler is receiving considerable attention for its outstanding properties. Literature available shows that Graphene oxide nano filler can be used to improve the mechanical properties. The use of Graphene oxide in vibration attenuation by enhancing the passive damping in fiber reinforced polymer composite has not been fully explored. The objective of this work is to investigate the dynamic behaviour of Glass fiber-reinforced composite embedded with Graphene oxide nano filler. Graphene oxide is dispersed in epoxy resin with various concentration (0.1%, 0.5% and 1%wt) using ultra-sonification process. Composite laminates were made using the traditional hand-lay-up followed by vacuum bag process. Experimental modal analysis using traditional `strike method' is used to evaluate modal parameters using FFT analyzer and Data Acquisition System. Experiments were carried out for two different fiber orientations viz 0 ➙ & 45 ➙ and two boundary conditions (Free-Free and Cantilever). The modal parameters such as natural frequency, mode shape, damping ratio were studied. This research work demonstrates the vibration damping behaviour with incorporation of Graphene oxide and provides a basic understanding of the damping characteristics in design and manufacture of high performance composites.

Nano-modification to improve the ductility of cementitious composites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yeşilmen, Seda; Al-Najjar, Yazin; Balav, Mohammad Hatam

2015-10-15

Effect of nano-sized mineral additions on ductility of engineered cementitious composites (ECC) containing high volumes of fly ash was investigated at different hydration degrees. Various properties of ECC mixtures with different mineral additions were compared in terms of microstructural properties of matrix, fiber-matrix interface, and fiber surface to assess improvements in ductility. Microstructural characterization was made by measuring pore size distributions through mercury intrusion porosimetry (MIP). Hydration characteristics were assessed using thermogravimetric analysis/differential thermal analysis (TGA/DTA), and fiber-matrix interface and fiber surface characteristics were assessed using scanning electron microscopy (SEM) through a period of 90 days. Moreover, compressive and flexuralmore » strength developments were monitored for the same period. Test results confirmed that mineral additions could significantly improve both flexural strength and ductility of ECC, especially at early ages. Cheaper Nano-CaCO{sub 3} was more effective compared to nano-silica. However, the crystal structure of CaCO{sub 3} played a very important role in the range of expected improvements.« less

Low Loss Graded Index Polymer Optical Fiber for Local Networking

DOE Office of Scientific and Technical Information (OSTI.GOV)

Claus, Richard Otto

The objective of this Department of Energy SBIR program has been to develop technology for the advancement of advanced computing systems. NanoSonic worked with two subcontractors, the Polymicro Division of Molex, a U.S.-based manufacturer of specialized optical fiber and fiber components, and Virginia Tech, a research university involved through the Global Environment for Network Innovations (GENI) program in high-speed computer networking research. NanoSonic developed a patented molecular-level self-assembly process to manufacture polymer-based optical fibers in a way similar to the modified chemical vapor deposition (MCVD) approach typically used to make glass optical fibers. Although polymer fiber has a higher attenuationmore » per unit length than glass fiber, short connectorized polymer fiber jumpers offer significant cost savings over their glass counterparts, particularly due to the potential use of low-cost plastic fiber connectors. As part of the SBIR commercialization process, NanoSonic exclusively licensed this technology to a large ($100B+ market cap) U.S.-based manufacturing conglomerate near the end of the first year of the Phase II program. With this base technology developed and licensed, NanoSonic then worked with Polymicro to address secondary program goals of using related but not conflicting production methods to enhance the performance of other specialty optical fiber products and components, and Virginia Tech continued its evaluation of developed polymer fibers in its network infrastructure system on the university campus. We also report our current understanding of the observation during the Phase I program of quantum conductance and partial quantum conductance in metal-insulator-metal (MIM) devices. Such conductance behavior may be modeled as singlemode behavior in one-dimensional electrically conducting waveguides, similar in principle to singlemode optical propagation in dielectric fiber waveguides. Although NanoSonic has not licensed

Higher-order micro-fiber modes for Escherichia coli manipulation using a tapered seven-core fiber

PubMed Central

Rong, Qiangzhou; Zhou, Yi; Yin, Xunli; Shao, Zhihua; Qiao, Xueguang

2017-01-01

Optical manipulation using optical micro- and nano-fibers has shown potential for controlling bacterial activities such as E. coli trapping, propelling, and binding. Most of these manipulations have been performed using the propagation of the fundamental mode through the fiber. However, along the maximum mode-intensity axis, the higher-order modes have longer evanescent field extensions and larger field amplitudes at the fiber waist than the fundamental mode, opening up new possibilities for manipulating E. coli bacteria. In this work, a compact seven-core fiber (SCF)-based micro-fiber/optical tweezers was demonstrated for trapping, propelling, and rotating E. coli bacteria using the excitation of higher-order modes. The diameter of the SCF taper was 4 µm at the taper waist, which was much larger than that of previous nano-fiber tweezers. The laser wavelength was tunable from 1500 nm to 1600 nm, simultaneously causing photophoretic force, gradient force, and scattering force. This work provides a new opportunity for better understanding optical manipulation using higher-order modes at the single-cell level. PMID:28966849

Higher-order micro-fiber modes for Escherichia coli manipulation using a tapered seven-core fiber.

PubMed

Rong, Qiangzhou; Zhou, Yi; Yin, Xunli; Shao, Zhihua; Qiao, Xueguang

2017-09-01

Optical manipulation using optical micro- and nano-fibers has shown potential for controlling bacterial activities such as E. coli trapping, propelling, and binding. Most of these manipulations have been performed using the propagation of the fundamental mode through the fiber. However, along the maximum mode-intensity axis, the higher-order modes have longer evanescent field extensions and larger field amplitudes at the fiber waist than the fundamental mode, opening up new possibilities for manipulating E. coli bacteria. In this work, a compact seven-core fiber (SCF)-based micro-fiber/optical tweezers was demonstrated for trapping, propelling, and rotating E. coli bacteria using the excitation of higher-order modes. The diameter of the SCF taper was 4 µm at the taper waist, which was much larger than that of previous nano-fiber tweezers. The laser wavelength was tunable from 1500 nm to 1600 nm, simultaneously causing photophoretic force, gradient force, and scattering force. This work provides a new opportunity for better understanding optical manipulation using higher-order modes at the single-cell level.

Combining flagelliform and dragline spider silk motifs to produce tunable synthetic biopolymer fibers.

PubMed

Teulé, Florence; Addison, Bennett; Cooper, Alyssa R; Ayon, Joel; Henning, Robert W; Benmore, Chris J; Holland, Gregory P; Yarger, Jeffery L; Lewis, Randolph V

2012-06-01

The two Flag/MaSp 2 silk proteins produced recombinantly were based on the basic consensus repeat of the dragline silk spidroin 2 protein (MaSp 2) from the Nephila clavipes orb weaving spider. However, the proline-containing pentapeptides juxtaposed to the polyalanine segments resembled those found in the flagelliform silk protein (Flag) composing the web spiral: (GPGGX(1) GPGGX(2))(2) with X(1) /X(2) = A/A or Y/S. Fibers were formed from protein films in aqueous solutions or extruded from resolubilized protein dopes in organic conditions when the Flag motif was (GPGGX(1) GPGGX(2))(2) with X(1) /X(2) = Y/S or A/A, respectively. Post-fiber processing involved similar drawing ratios (2-2.5×) before or after water-treatment. Structural (ssNMR and XRD) and morphological (SEM) changes in the fibers were compared to the mechanical properties of the fibers at each step. Nuclear magnetic resonance indicated that the fraction of β-sheet nanocrystals in the polyalanine regions formed upon extrusion, increased during stretching, and was maximized after water-treatment. X-ray diffraction showed that nanocrystallite orientation parallel to the fiber axis increased the ultimate strength and initial stiffness of the fibers. Water furthered nanocrystal orientation and three-dimensional growth while plasticizing the amorphous regions, thus producing tougher fibers due to increased extensibility. These fibers were highly hygroscopic and had similar internal network organization, thus similar range of mechanical properties that depended on their diameters. The overall structure of the consensus repeat of the silk-like protein dictated the mechanical properties of the fibers while protein molecular weight limited these same properties. Subtle structural motif re-design impacted protein self-assembly mechanisms and requirements for fiber formation. Copyright © 2011 Wiley Periodicals, Inc.

Combining flagelliform and dragline spider silk motifs to produce tunable synthetic biopolymer fibers

PubMed Central

Teulé, Florence; Addison, Bennett; Cooper, Alyssa R.; Ayon, Joel; Henning, Robert W.; Benmore, Chris J.; Holland, Gregory P.; Yarger, Jeffery L.; Lewis, Randolph V.

2012-01-01

The two Flag/MaSp 2 silk proteins produced recombinantly were based on the basic consensus repeat of the dragline silk spidroin 2 protein (MaSp 2) from the Nephila clavipes orb weaving spider. However, the proline-containing pentaptides juxtaposed to the polyalanine segments resembled those found in the flagelliform silk protein (Flag) composing the web spiral: (GPGGX1 GPGGX2)2 with X1/X2=A/A or Y/S. Fibers were formed from protein films in aqueous solutions or extruded from resolubilized protein dopes in organic conditions when the Flag motif was (GPGGX1 GPGGX2)2 with X1/X2 = Y/S or A/A, respectively. Post fiber processing involved similar drawing ratios (2–2.5×) before or after water-treatment. Structural (ssNMR and XRD) and morphological (SEM) changes in the fibers were compared to the mechanical properties of the fibers at each step. NMR indicated that the fraction of β-sheet nanocrystals in the polyalanine regions formed upon extrusion, increased during stretching, and was maximized after water-treatment. XRD showed that nanocrystallite orientation parallel to the fiber axis increased the ultimate strength and initial stiffness of the fibers. Water furthered nanocrystal orientation and three-dimensional growth while plasticizing the amorphous regions, thus producing tougher fibers due to increased extensibility. These fibers were highly hygroscopic and had similar internal network organization, thus similar range of mechanical properties that depended on their diameters. The overall structure of the consensus repeat of the silk-like protein dictated the mechanical properties of the fibers while protein molecular weight limited these same properties. Subtle structural motif redesign impacted protein self-assembly mechanisms and requirements for fiber formation. PMID:22012252

Multifunctional Textured Surfaces with Enhanced Friction and Hydrophobic Behaviors Produced by Fiber Debonding and Pullout.

PubMed

Rizvi, Reza; Anwer, Ali; Fernie, Geoff; Dutta, Tilak; Naguib, Hani

2016-11-02

Fiber debonding and pullout are well-understood processes that occur during damage and failure events in composite materials. In this study, we show how these mechanisms, under controlled conditions, can be used to produce multifunctional textured surfaces. A two-step process consisting of (1) achieving longitudinal fiber alignment followed by (2) cutting, rearranging, and joining is used to produce the textured surfaces. This process employs common composite manufacturing techniques and uses no reactive chemicals or wet handling, making it suitable for scalability. This uniform textured surface is due to the fiber debonding and pullout occurring during the cutting process. Using well-established fracture mechanics principles for composite materials, we demonstrate how different material parameters such as fiber geometry, fiber and matrix stiffness and strength, and interface behavior can be used to achieve multifunctional textured surfaces. The resulting textured surfaces show very high friction coefficients on wet ice (9× improvement), indicating their promising potential as materials for ice traction/tribology. Furthermore, the texturing enhances the surface's hydrophobicity as indicated by an increase in the contact angle of water by 30%. The substantial improvements to surface tribology and hydrophobicity make fiber debonding and pullout an effective, simple, and scalable method of producing multifunctional textured surfaces.

Polarization control in flexible interference lithography for nano-patterning of different photonic structures with optimized contrast.

PubMed

He, Jianfang; Fang, Xiaohui; Lin, Yuanhai; Zhang, Xinping

2015-05-04

Half-wave plates were introduced into an interference-lithography scheme consisting of three fibers that were arranged into a rectangular triangle. Such a flexible and compact geometry allows convenient tuning of the polarizations of both the UV laser source and each branch arm. This not only enables optimization of the contrast of the produced photonic structures with expected square lattices, but also multiplies the nano-patterning functions of a fixed design of fiber-based interference lithography. The patterns of the photonic structures can be thus tuned simply by rotating a half-wave plate.

Nano-RuO2 -Decorated Holey Graphene Composite Fibers for Micro-Supercapacitors with Ultrahigh Energy Density.

PubMed

Zhai, Shengli; Wang, Chaojun; Karahan, Huseyin Enis; Wang, Yanqing; Chen, Xuncai; Sui, Xiao; Huang, Qianwei; Liao, Xiaozhou; Wang, Xin; Chen, Yuan

2018-06-07

Compactness and versatility of fiber-based micro-supercapacitors (FMSCs) make them promising for emerging wearable electronic devices as energy storage solutions. But, increasing the energy storage capacity of microscale fiber electrodes, while retaining their high power density, remains a significant challenge. Here, this issue is addressed by incorporating ultrahigh mass loading of ruthenium oxide (RuO 2 ) nanoparticles (up to 42.5 wt%) uniformly on nanocarbon-based microfibers composed largely of holey reduced graphene oxide (HrGO) with a lower amount of single-walled carbon nanotubes as nanospacers. This facile approach involes (1) space-confined hydrothermal assembly of highly porous but 3D interconnected carbon structure, (2) impregnating wet carbon structures with aqueous Ru 3+ ions, and (3) anchoring RuO 2 nanoparticles on HrGO surfaces. Solid-state FMSCs assembled using those fibers demonstrate a specific volumetric capacitance of 199 F cm -3 at 2 mV s -1 . Fabricated FMSCs also deliver an ultrahigh energy density of 27.3 mWh cm -3 , the highest among those reported for FMSCs to date. Furthermore, integrating 20 pieces of FMSCs with two commercial flexible solar cells as a self-powering energy system, a light-emitting diode panel can be lit up stably. The current work highlights the excellent potential of nano-RuO 2 -decorated HrGO composite fibers for constructing micro-supercapacitors with high energy density for wearable electronic devices. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Remote optical sensing on the nanometer scale with a bowtie aperture nano-antenna on a fiber tip of scanning near-field optical microscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Atie, Elie M.; Xie, Zhihua; El Eter, Ali

2015-04-13

Plasmonic nano-antennas have proven the outstanding ability of sensing chemical and physical processes down to the nanometer scale. Sensing is usually achieved within the highly confined optical fields generated resonantly by the nano-antennas, i.e., in contact to the nanostructures. In this paper, we demonstrate the sensing capability of nano-antennas to their larger scale environment, well beyond their plasmonic confinement volume, leading to the concept of “remote” (non contact) sensing on the nanometer scale. On the basis of a bowtie-aperture nano-antenna (BNA) integrated at the apex of a SNOM (Scanning Near-field Optical Microscopy) fiber tip, we introduce an ultra-compact, moveable, andmore » background-free optical nanosensor for the remote sensing of a silicon surface (up to distance of 300 nm). Sensitivity of the BNA to its large scale environment is high enough to expect the monitoring and control of the spacing between the nano-antenna and a silicon surface with sub-nanometer accuracy. This work paves the way towards an alternative class of nanopositioning techniques, based on the monitoring of diffraction-free plasmon resonance, that are alternative to nanomechanical and diffraction-limited optical interference-based devices.« less

Highly non-linear solid core photonic crystal fiber with one nano hole

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gangwar, Rahul Kumar, E-mail: rahul0889@gmail.com; Bhardwaj, Vanita, E-mail: bhardwajphy12@gmail.com; Singh, Vinod Kumar, E-mail: singh.vk.ap@ismdhanbad.co.in

2015-08-28

The numerical study of newly designed solid core photonic crystal fiber (SCPCF) having three hexagonal air hole rings in cladding region and one small nano hole at the center are presented. By using full vectorial finite element method (FV-FEM), we analyses the optical properties like effective area, nonlinearity and confinement loss of the proposed PCF. Results show that the change in core diameter controls the effective area, nonlinearity and confinement loss. A low effective area (3.34 µm{sup 2}), high nonlinearity (36.34 W{sup −1}km{sup −1}) and low confinement loss (0.00106 dB/km) are achieved at the communication wavelength 1.55 µm for themore » SCPCF having core air hole diameter 0.10 µm, cladding air holes diameter 1.00 µm and pitch 2.50 µm. This type of PCF is very useful in non-linear applications such as supercontinuum generation, four wave mixing, second harmonic generation etc.« less

Continuous method of producing silicon carbide fibers

NASA Technical Reports Server (NTRS)

Barnard, Thomas Duncan (Inventor); Nguyen, Kimmai Thi (Inventor); Rabe, James Alan (Inventor)

1999-01-01

This invention pertains to a method for production of polycrystalline ceramic fibers from silicon oxycarbide (SiCO) ceramic fibers wherein the method comprises heating an amorphous ceramic fiber containing silicon and carbon in an inert environment comprising a boron oxide and carbon monoxide at a temperature sufficient to convert the amorphous ceramic fiber to a polycrystalline ceramic fiber. By having carbon monoxide present during the heating of the ceramic fiber, it is possible to achieve higher production rates on a continuous process.

Spider Silk Fibers Spun from Soluble Recombinant Silk Produced in Mammalian Cells

NASA Astrophysics Data System (ADS)

Lazaris, Anthoula; Arcidiacono, Steven; Huang, Yue; Zhou, Jiang-Feng; Duguay, François; Chretien, Nathalie; Welsh, Elizabeth A.; Soares, Jason W.; Karatzas, Costas N.

2002-01-01

Spider silks are protein-based ``biopolymer'' filaments or threads secreted by specialized epithelial cells as concentrated soluble precursors of highly repetitive primary sequences. Spider dragline silk is a flexible, lightweight fiber of extraordinary strength and toughness comparable to that of synthetic high-performance fibers. We sought to ``biomimic'' the process of spider silk production by expressing in mammalian cells the dragline silk genes (ADF-3/MaSpII and MaSpI) of two spider species. We produced soluble recombinant (rc)-dragline silk proteins with molecular masses of 60 to 140 kilodaltons. We demonstrated the wet spinning of silk monofilaments spun from a concentrated aqueous solution of soluble rc-spider silk protein (ADF-3; 60 kilodaltons) under modest shear and coagulation conditions. The spun fibers were water insoluble with a fine diameter (10 to 40 micrometers) and exhibited toughness and modulus values comparable to those of native dragline silks but with lower tenacity. Dope solutions with rc-silk protein concentrations >20% and postspinning draw were necessary to achieve improved mechanical properties of the spun fibers. Fiber properties correlated with finer fiber diameter and increased birefringence.

Development program to produce mullite fiber insulation

NASA Technical Reports Server (NTRS)

Long, W. G.

1975-01-01

Processing methods were utilized to form a mullite fiber-Kaowool felt. The formation of a blended felt using the Rotoformer wet-laying method was successful. Felt products were evaluated for tensile strength, thermal stability, thermal conductivity and structural integrity at 1259 C and 1371 C. Textile processing methods failed in an attempt to form a yarn from staple and multifilament mullite fiber due to fiber damage through mechanical handling. The refractoriness of pure Kaowool ceramic fiber is improved with additions of 30% or greater mullite fiber.

Uniformly thinned optical fibers produced via HF etching with spectral and microscopic verification.

PubMed

Bal, Harpreet K; Brodzeli, Zourab; Dragomir, Nicoleta M; Collins, Stephen F; Sidiroglou, Fotios

2012-05-01

A method for producing uniformly thinned (etched) optical fibers is described, which can also be employed to etch optical fibers containing a Bragg grating (FBG) uniformly for evanescent-field-based sensing and other applications. Through a simple modification of this method, the fabrication of phase-shifted FBGs based on uneven etching is also shown. The critical role of how a fiber is secured is shown, and the success of the method is illustrated, by differential interference contrast microscopy images of uniformly etched FBGs. An etched FBG sensor for the monitoring of the refractive index of different glycerin solutions is demonstrated.

Low-temperature method of producing nano-scaled graphene platelets and their nanocomposites

DOEpatents

Zhamu, Aruna [Centerville, OH; Shi, Jinjun [Columbus, OH; Guo, Jiusheng [Centerville, OH; Jang, Bor Z [Centerville, OH

2012-03-13

A method of exfoliating a layered material to produce separated nano-scaled platelets having a thickness smaller than 100 nm. The method comprises: (a) providing a graphite intercalation compound comprising a layered graphite containing expandable species residing in an interlayer space of the layered graphite; (b) exposing the graphite intercalation compound to an exfoliation temperature lower than 650.degree. C. for a duration of time sufficient to at least partially exfoliate the layered graphite without incurring a significant level of oxidation; and (c) subjecting the at least partially exfoliated graphite to a mechanical shearing treatment to produce separated platelets. The method can further include a step of dispersing the platelets in a polymer or monomer solution or suspension as a precursor step to nanocomposite fabrication.

Biomimetic fiber mesh scaffolds based on gelatin and hydroxyapatite nano-rods: Designing intrinsic skills to attain bone reparation abilities.

PubMed

Sartuqui, Javier; Gravina, A Noel; Rial, Ramón; Benedini, Luciano A; Yahia, L'Hocine; Ruso, Juan M; Messina, Paula V

2016-09-01

Intrinsic material skills have a deep effect on the mechanical and biological performance of bone substitutes, as well as on its associated biodegradation properties. In this work we have manipulated the preparation of collagenous derived fiber mesh frameworks to display a specific composition, morphology, open macroporosity, surface roughness and permeability characteristics. Next, the effect of the induced physicochemical attributes on the scaffold's mechanical behavior, bone bonding potential and biodegradability were evaluated. It was found that the scaffold microstructure, their inherent surface roughness, and the compression strength of the gelatin scaffolds can be modulated by the effect of the cross-linking agent and, essentially, by mimicking the nano-scale size of hydroxyapatite in natural bone. A clear effect of bioactive hydroxyapatite nano-rods on the scaffolds skills can be appreciated and it is greater than the effect of the cross-linking agent, offering a huge perspective for the upcoming progress of bone implant technology. Copyright © 2016 Elsevier B.V. All rights reserved.

Numerical modeling study of silver nano-filling based on grapefruit-type photonic crystal fiber sensor

NASA Astrophysics Data System (ADS)

Zheng, Yibo; Zhang, Lei; Wang, Yuan

2017-10-01

In this letter, surface plasmon resonance sensors based on grapefruit-type photonic crystal fiber (PCF)with different silver nano-filling structure have been analyzed and compared though the finite element method (FEM). The regularity of the resonant wavelength changing with refractive index of the sample has been numerically simulated. The surface plasmon resonance (SPR) sensing properties have been numerically simulated in both areas of resonant wavelength and intensity detection. Numerical results show that excellent sensor resolution of 4.17×10-5RIU can be achieved as the radius of the filling silver nanowires is 150 nm by spectrum detection method. Comprehensive comparison indicates that the 150 nm silver wire filling structure is suitable for spectrum detection and 30 nm silver film coating structure is suitable for the amplitude detection.

Nano-scaled graphene platelets with a high length-to-width aspect ratio

DOEpatents

Zhamu, Aruna; Guo, Jiusheng; Jang, Bor Z.

2010-09-07

This invention provides a nano-scaled graphene platelet (NGP) having a thickness no greater than 100 nm and a length-to-width ratio no less than 3 (preferably greater than 10). The NGP with a high length-to-width ratio can be prepared by using a method comprising (a) intercalating a carbon fiber or graphite fiber with an intercalate to form an intercalated fiber; (b) exfoliating the intercalated fiber to obtain an exfoliated fiber comprising graphene sheets or flakes; and (c) separating the graphene sheets or flakes to obtain nano-scaled graphene platelets. The invention also provides a nanocomposite material comprising an NGP with a high length-to-width ratio. Such a nanocomposite can become electrically conductive with a small weight fraction of NGPs. Conductive composites are particularly useful for shielding of sensitive electronic equipment against electromagnetic interference (EMI) or radio frequency interference (RFI), and for electrostatic charge dissipation.

All-fiber pyroelectric nanogenerator

NASA Astrophysics Data System (ADS)

Ghosh, Sujoy Kumar; Xie, Mengying; Bowen, Christopher Rhys; Mandal, Dipankar

2018-04-01

An all-fiber pyroelectric nanogenerator (PyNG) is fabricated where both the active pyroelectric component and the electrodes were composed of fiber. The pyroelectric component was made with randomly organized electrospun PVDF nano-fibers possessing ferroelectric β- and γ-phases. The PyNG possess higher level of sensitivity which can detect very low level of temperature fluctuation, as, low as, 2 K. In addition, the thermal energy harvesting ability of the PyNG under several temperature variations and cycling frequencies paves the way for next generation thermal sensor and self-powered flexible micro-electronics.

A study on the tensile properties of silicone rubber/polypropylene fibers/silica hybrid nanocomposites.

PubMed

Ziraki, Sahar; Zebarjad, Seyed Mojtaba; Hadianfard, Mohammad Jafar

2016-04-01

Metacarpophalangeal joint implants have been usually made of silicone rubber. In the current study, silica nano particles and polypropylene fibers were added to silicone rubber to improve silicone properties. The effect of the addition of silica nano particles and polypropylene fibers on the tensile behavior of the resultant composites were investigated. Composite samples with different content of PP fibers and Silica nano particles (i. e. 0, 1 and 2wt%) as well as the hybrid composite of silicone rubber with 1wt% SiO2 and 1wt% PP fiber were prepared. Tensile tests were done at constant cross head speed. To study the body fluid effect on the mechanical properties of silicone rubber composites, samples soaked in simulated body fluid (SBF) at 37°C were also tested. The morphology of the samples were studied by scanning electron microscope. Results of analysis revealed that an increase in PP fibers and silica nano particles content to 2wt%, increases the tensile strength of silicone rubber of about 75% and 42% respectively. It was found out that the strength of the samples decreases after being soaked in simulated body fluid, though composites with PP fibers as the reinforcement showed less property degradation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Fabrication and characterization of electrospun cellulose/nano-hydroxyapatite nanofibers for bone tissue engineering.

PubMed

Ao, Chenghong; Niu, Yan; Zhang, Ximu; He, Xu; Zhang, Wei; Lu, Canhui

2017-04-01

Nanofibrous scaffolds from cotton cellulose and nano-hydroxyapatite (nano-HA) were electrospun for bone tissue engineering. The solution properties of cellulose/nano-HA spinning dopes and their associated electrospinnability were characterized. Morphological, thermal and mechanical properties of the electrospun cellulose/nano-HA nanocomposite nanofibers (ECHNN) were measured and the biocompatibility of ECHNN with human dental follicle cells (HDFCs) was evaluated. Scanning electron microscope (SEM) images indicated that the average diameter of ECHNN increased with a higher nano-HA loading and the fiber diameter distributions were well within the range of natural ECM (extra cellular matrix) fibers (50-500nm). The ECHNN exhibited extraordinary mechanical properties with a tensile strength and a Young's modulus up to 70.6MPa and 3.12GPa respectively. Moreover, it was discovered that the thermostability of the ECHNN could be enhanced with the incorporation of nano-HA. Cell culture experiments demonstrated that the ECHNN scaffolds were quite biocompatible for HDFCs attachment and proliferation, suggesting their great potentials as scaffold materials in bone tissue engineering. Copyright © 2017 Elsevier B.V. All rights reserved.

Method for the preparation of carbon fiber from polyolefin fiber precursor, and carbon fibers made thereby

DOEpatents

Naskar, Amit Kumar; Hunt, Marcus Andrew; Saito, Tomonori

2015-08-04

Methods for the preparation of carbon fiber from polyolefin fiber precursor, wherein the polyolefin fiber precursor is partially sulfonated and then carbonized to produce carbon fiber. Methods for producing hollow carbon fibers, wherein the hollow core is circular- or complex-shaped, are also described. Methods for producing carbon fibers possessing a circular- or complex-shaped outer surface, which may be solid or hollow, are also described.

Method of producing carbon coated nano- and micron-scale particles

DOEpatents

Perry, W. Lee; Weigle, John C; Phillips, Jonathan

2013-12-17

A method of making carbon-coated nano- or micron-scale particles comprising entraining particles in an aerosol gas, providing a carbon-containing gas, providing a plasma gas, mixing the aerosol gas, the carbon-containing gas, and the plasma gas proximate a torch, bombarding the mixed gases with microwaves, and collecting resulting carbon-coated nano- or micron-scale particles.

Method of producing superconducting fibers of bismuth strontium calcium copper oxide (Bi(2212) and Bi(2223))

DOEpatents

Schwartzkopf, Louis A.

1991-10-01

Fibers of Bi(2212) have been produce by pendant drop melt extraction. This technique involves the end of a rod of Bi(2212) melted with a hydrogen-oxygen torch, followed by lowering onto the edge of a spinning wheel. The fibers are up to 15 cm in length with the usual lateral dimensions, ranging from 20 um to 30 um. The fibers require a heat treatment to make them superconducting.

Methods for Producing High-Performance Silicon Carbide Fibers, Architectural Preforms, and High-Temperature Composite Structures

NASA Technical Reports Server (NTRS)

Yun, Hee-Mann (Inventor); DiCarlo, James A. (Inventor)

2014-01-01

Methods are disclosed for producing architectural preforms and high-temperature composite structures containing high-strength ceramic fibers with reduced preforming stresses within each fiber, with an in-situ grown coating on each fiber surface, with reduced boron within the bulk of each fiber, and with improved tensile creep and rupture resistance properties tier each fiber. The methods include the steps of preparing an original sample of a preform formed from a pre-selected high-strength silicon carbide ceramic fiber type, placing the original sample in a processing furnace under a pre-selected preforming stress state and thermally treating the sample in the processing furnace at a pre-selected processing temperature and hold time in a processing gas having a pre-selected composition, pressure, and flow rate. For the high-temperature composite structures, the method includes additional steps of depositing a thin interphase coating on the surface of each fiber and forming a ceramic or carbon-based matrix within the sample.

The effect of nano-SiC on characteristics of ADC12/nano-SiC composite with Sr and TiB addition produced by stir casting process

NASA Astrophysics Data System (ADS)

Anne Zulfia, S.; Salshabia, Nadella; Dhaneswara, Donanta; Utomo, Budi Wahyu

2018-05-01

ADC12 reinforced nano SiC has been successfully produced by stir casting process. Nano SiC was added into ADC12 alloy varied from 0.05 to 0.3 vf-% while Al-5Ti-1B and Sr were kept constant at 0.04 and 0.02 wt-% respectively to all composites. Mg was added 10 wt% to improve reinforce's wettability. The addition of Al-5Ti-1B to the alloy was as grain refiner while Sr was added to modify Mg2Si. All composites were characterized both microstructures analysis and mechanical properties include tensile strength, hardness, wear rate, impact strength, and porosity. The highest properties of composites was obtained at 0.3 vf-% nano SiC addition with UTS of 155.4 MPa, hardness of 46.16 HRB, impact strength of 0.22 J/mm2, and wear rate of 1.71 × 10-5 mm3/m. Tensile strength and hardness increased as grain size and porosities decreased. The highest wear resistance was investigated on the composition with the highest hardness. Impact strength decreased due to increasing volume fraction of nano-SiC. The phases present in microsturucture was dominantly Mg2Si which also affected mechanical properties of these composites.

Method of producing superconducting fibers of YBa[sub 2]Cu[sub 3]O[sub x

DOEpatents

Schwartzkopf, L.A.; Ostenson, J.E.; Finnemore, D.K.

1990-11-13

Fibers of YBa[sub 2]Cu[sub 3]O[sub x] have been produce by pendant drop melt extraction. This technique involves the end of a rod of YBa[sub 2]Cu[sub 3]O[sub x] melted with a hydrogen-oxygen torch, followed by lowering onto the edge of a spinning wheel. The fibers are up to 10 cm in length with the usual lateral dimensions, ranging from 20 [mu]m to 125 [mu]m. The fibers require a heat treatment to make them superconducting.

Investigation of influence of conductivity on the polyaniline fiber mats, produced via electrospinning

NASA Astrophysics Data System (ADS)

Varnaitė-Žuravliova, Sandra; Savest, Natalja; Abraitienė, Aušra; Baltušnikaitė-Guzaitienė, Julija; Krumme, Andres

2018-05-01

Intrinsically conductive polymers are one very attractive material, because of their good electrical, electrochemical and optical properties, and a wide range of applications. The spinnability of Polyaniline (PANI) solutions is generally insufficient for it to be electrospun directly into fibers, but addition of another polymer to the organic solutions or usage of dopant and solvent may improve it. The aim of the research was: to produce nanofibers of the smallest diameter as possible by using conventional electrospinning setup; to investigate the influence of viscosity and electrical conductivity to the spinnability of PANI solutions; to control the electrical conductivity of prepared solutions and electrospun nanofibers by changing concentrations of chemicals used. The results of investigations made with prepared solutions shave showed, that the viscosity increases and the electrical conductivity is tending to decrease with increase of Polyethylenoxide (PEO) concentration in the spinning solution. In order to achieve greater conductivity, the Dimethylformamide (DMF) was added as a dopant. Though the conductivity of solutions was reached high enough, but the loss in viscosity resulted in depriation of greater spinnability of PANI nanofibers. Also it was noticed, that despite the fact that the electrical conductivity of all solutions was different, the electrical conductivity of fiber mats can be divided in two groups: fiber mats without DMF and fiber mats with DMF. The morphological analysis of produced fiber mats have showed, that higher PEO concentration resulted in thicker PANI nanofibers—the diameter varied from 333 nm till 4434 nm. The usage of DMF gave an opportunity to receive almost twice thinner conductive PANI nanofibers with narrower distribution in diameter. Slower flow rate of the electrospinning process resulted in thinner nanofibers as well.

Nano-material and method of fabrication

DOEpatents

Menchhofer, Paul A; Seals, Roland D; Howe, Jane Y; Wang, Wei

2015-02-03

A fluffy nano-material and method of manufacture are described. At 2000.times. magnification the fluffy nanomaterial has the appearance of raw, uncarded wool, with individual fiber lengths ranging from approximately four microns to twenty microns. Powder-based nanocatalysts are dispersed in the fluffy nanomaterial. The production of fluffy nanomaterial typically involves flowing about 125 cc/min of organic vapor at a pressure of about 400 torr over powder-based nano-catalysts for a period of time that may range from approximately thirty minutes to twenty-four hours.

Bone plate composed of a ternary nano-hydroxyapatite/polyamide 66/glass fiber composite: biomechanical properties and biocompatibility

PubMed Central

Qiao, Bo; Li, Jidong; Zhu, Qingmao; Guo, Shuquan; Qi, Xiaotong; Li, Weichao; Wu, Jun; Liu, Yang; Jiang, Dianming

2014-01-01

An ideal bone plate for internal fixation of bone fractures should have good biomechanical properties and biocompatibility. In this study, we prepared a new nondegradable bone plate composed of a ternary nano-hydroxyapatite/polyamide 66/glass fiber (n-HA/PA66/GF) composite. A breakage area on the n-HA/PA66/GF plate surface was characterized by scanning electron microscopy. Its mechanical properties were investigated using bone-plate constructs and biocompatibility was evaluated in vitro using bone marrow-derived mesenchymal stem cells. The results confirmed that adhesion between the n-HA/PA66 matrix and the glass fibers was strong, with only a few fibers pulled out at the site of breakage. Fractures fixed by the n-HA/PA66/GF plate showed lower stiffness and had satisfactory strength compared with rigid fixation using a titanium plate. Moreover, the results with regard to mesenchymal stem cell morphology, MTT assay, Alizarin Red S staining, enzyme-linked immunosorbent assay, and reverse transcription polymerase chain reaction for alkaline phosphatase and osteocalcin showed that the n-HA/PA66/GF composite was suitable for attachment and proliferation of mesenchymal stem cells, and did not have a negative influence on matrix mineralization or osteogenic differentiation of mesenchymal stem cells. These observations indicate that the n-HA/PA66/GF plate has good biomechanical properties and biocompatibility, and may be considered a new option for internal fixation in orthopedic surgery. PMID:24669191

Bone plate composed of a ternary nano-hydroxyapatite/polyamide 66/glass fiber composite: biomechanical properties and biocompatibility.

PubMed

Qiao, Bo; Li, Jidong; Zhu, Qingmao; Guo, Shuquan; Qi, Xiaotong; Li, Weichao; Wu, Jun; Liu, Yang; Jiang, Dianming

2014-01-01

An ideal bone plate for internal fixation of bone fractures should have good biomechanical properties and biocompatibility. In this study, we prepared a new nondegradable bone plate composed of a ternary nano-hydroxyapatite/polyamide 66/glass fiber (n-HA/PA66/GF) composite. A breakage area on the n-HA/PA66/GF plate surface was characterized by scanning electron microscopy. Its mechanical properties were investigated using bone-plate constructs and biocompatibility was evaluated in vitro using bone marrow-derived mesenchymal stem cells. The results confirmed that adhesion between the n-HA/PA66 matrix and the glass fibers was strong, with only a few fibers pulled out at the site of breakage. Fractures fixed by the n-HA/PA66/GF plate showed lower stiffness and had satisfactory strength compared with rigid fixation using a titanium plate. Moreover, the results with regard to mesenchymal stem cell morphology, MTT assay, Alizarin Red S staining, enzyme-linked immunosorbent assay, and reverse transcription polymerase chain reaction for alkaline phosphatase and osteocalcin showed that the n-HA/PA66/GF composite was suitable for attachment and proliferation of mesenchymal stem cells, and did not have a negative influence on matrix mineralization or osteogenic differentiation of mesenchymal stem cells. These observations indicate that the n-HA/PA66/GF plate has good biomechanical properties and biocompatibility, and may be considered a new option for internal fixation in orthopedic surgery.

Studies on Effective Elastic Properties of CNT/Nano-Clay Reinforced Polymer Hybrid Composite

NASA Astrophysics Data System (ADS)

Thakur, Arvind Kumar; Kumar, Puneet; Srinivas, J.

2016-02-01

This paper presents a computational approach to predict elastic propertiesof hybrid nanocomposite material prepared by adding nano-clayplatelets to conventional CNT-reinforced epoxy system. In comparison to polymers alone/single-fiber reinforced polymers, if an additional fiber is added to the composite structure, it was found a drastic improvement in resultant properties. In this regard, effective elastic moduli of a hybrid nano composite are determined by using finite element (FE) model with square representative volume element (RVE). Continuum mechanics based homogenization of the nano-filler reinforced composite is considered for evaluating the volumetric average of the stresses and the strains under different periodic boundary conditions.A three phase Halpin-Tsai approach is selected to obtain the analytical result based on micromechanical modeling. The effect of the volume fractions of CNTs and nano-clay platelets on the mechanical behavior is studied. Two different RVEs of nano-clay platelets were used to investigate the influence of nano-filler geometry on composite properties. The combination of high aspect ratio of CNTs and larger surface area of clay platelets contribute to the stiffening effect of the hybrid samples. Results of analysis are validated with Halpin-Tsai empirical formulae.

Fabrication of nano-Fe3O4 3D structure on carbon fibers as a microwave absorber and EMI shielding composite by modified EPD method

NASA Astrophysics Data System (ADS)

Gholampoor, Mahdi; Movassagh-Alanagh, Farid; Salimkhani, Hamed

2017-02-01

Recently, electromagnetic interference (EMI) shielding materials have absorbed a lot of attention due to a growing need for application in the area of electronic and wireless devices. In this study, a carbon-based EMI shielding composite was fabricated by electrophoretic deposition of Fe3O4 nano-particles on carbon fibers (CFs) as a 3D structure incorporated with an epoxy resin. Co-precipitation method was employed to synthesize Fe3O4 nano-particles. This as-synthesized Fe3O4 nano-powder was then successfully deposited on CFs using a modified multi-step electrophoretic deposition (EPD) method. The results of structural studies showed that the Fe3O4 nano-particles (25 nm) were successfully and uniformly deposited on CFs. The measured magnetic properties of as-synthesized Fe3O4 nano-powder and nano-Fe3O4/CFs composite showed that the saturation magnetization of bare Fe3O4 was decreased from Ms = 72.3 emu/g to Ms = 33.1 emu/g for nano-Fe3O4/CFs composite and also corecivity of Fe3O4 was increased from Hc = 4.9 Oe to Hc = 168 Oe for composite. The results of microwave absorption tests revealed that the reflection loss (RL) of an epoxy-based nano-Fe3O4/CFs composite are significantly influenced by layer thickness. The maximum RL value of -10.21 dB at 10.12 GHz with an effective absorption bandwidth about 2 GHz was obtained for the sample with the thickness of 2 mm. It also exhibited an EMI shielding performance of -23 dB for whole the frequency range of 8.2-12.4 GHz.

Method for the preparation of carbon fiber from polyolefin fiber precursor

DOEpatents

Naskar, Amit Kumar; Hunt, Marcus Andrew; Saito, Tomonori

2017-11-28

Methods for the preparation of carbon fiber from polyolefin fiber precursor, wherein the polyolefin fiber precursor is partially sulfonated and then carbonized to produce carbon fiber. Methods for producing hollow carbon fibers, wherein the hollow core is circular- or complex-shaped, are also described. Methods for producing carbon fibers possessing a circular- or complex-shaped outer surface, which may be solid or hollow, are also described.

Extraction of cellulose nano-crystals from old corrugated container fiber using phosphoric acid and enzymatic hydrolysis followed by sonication.

PubMed

Tang, Yanjun; Shen, Xiaochuang; Zhang, Junhua; Guo, Daliang; Kong, Fangong; Zhang, Nan

2015-07-10

Due to its amazing physicochemical properties and high environmental compatibility, cellulose nano-crystals (CNC) hold great promise for serving as a strategic platform for sustainable development. Now, there has been growing interest in the development of processes using waste or residual biomass as CNC source for addressing economic and environmental concerns. In the present work, a combined process involving phosphoric acid hydrolysis, enzymatic hydrolysis and sonication was proposed aiming to efficiently exact CNC from low-cost old corrugated container (OCC) pulp fiber. The effect of enzymatic hydrolysis on the yield and microstructure of resulting CNC was highlighted. Results showed that the enzymatic hydrolysis was effective in enhancing CNC yield after phosphoric acid hydrolysis. CNC was obtained with a yield of 23.98 wt% via the combined process with phosphoric acid concentration of 60 wt%, cellulase dosage of 2 mL (84 EGU) per 2g fiber and sonication intensity of 200 W. Moreover, the presence of enzymatic hydrolysis imparted the obtained CNC with improved dispersion, increased crystallinity and thermal stability. Copyright © 2015 Elsevier Ltd. All rights reserved.

Bioactivity of cellulose acetate/hydroxyapatite nanoparticle composite fiber by an electro-spinning process.

PubMed

Kwak, Dae Hyun; Lee, Eun Ju; Kim, Deug Joong

2014-11-01

Hydroxyapatite/cellulose acetate composite webs were fabricated by an electro-spinning process. This electro-spinning process makes it possible to fabricate complex three-dimensional shapes. Nano fibrous web consisting of cellulose acetate and hydroxyapatite was produced from their mixture solution by using an electro-spinning process under high voltage. The surface of the electro-spun fiber was modified by a plasma and alkaline solution in order to increase its bioactivity. The structure, morphology and properties of the electro-spun fibers were investigated and an in-vitro bioactivity test was evaluated in simulated body fluid (SBF). Bioactivity of the electro-spun web was enhanced with the filler concentration and surface treatment. The surface changes of electro-spun fibers modified by plasma and alkaline solution were investigated by FT-IR (Fourier Transform Infrared Spectroscopy) and XPS (X-ray Photoelectron Spectroscopy).

Method of producing a silicon carbide fiber reinforced strontium aluminosilicate glass-ceramic matrix composite

NASA Technical Reports Server (NTRS)

Bansal, Narottam P. (Inventor)

1995-01-01

A SrO-Al2O3-2SrO2 (SAS) glass ceramic matrix is reinforced with CVD SiC continuous fibers. This material is prepared by casting a slurry of SAS glass powder into tapes. Mats of continuous CVD-SiC fibers are alternately stacked with the matrix tapes. This tape-mat stack is warm-pressed to produce a 'green' composite. Organic constituents are burned out of the 'green' composite, and the remaining interim material is hot pressed.

Could Nano-Structured Materials Enable the Improved Pressure Vessels for Deep Atmospheric Probes?

NASA Technical Reports Server (NTRS)

Srivastava, D.; Fuentes, A.; Bienstock, B.; Arnold, J. O.

2005-01-01

A viewgraph presentation on the use of Nano-Structured Materials to enable pressure vessel structures for deep atmospheric probes is shown. The topics include: 1) High Temperature/Pressure in Key X-Environments; 2) The Case for Use of Nano-Structured Materials Pressure Vessel Design; 3) Carbon based Nanomaterials; 4) Nanotube production & purification; 5) Nanomechanics of Carbon Nanotubes; 6) CNT-composites: Example (Polymer); 7) Effect of Loading sequence on Composite with 8% by volume; 8) Models for Particulate Reinforced Composites; 9) Fullerene/Ti Composite for High Strength-Insulating Layer; 10) Fullerene/Epoxy Composite for High Strength-Insulating Layer; 11) Models for Continuous Fiber Reinforced Composites; 12) Tensile Strength for Discontinuous Fiber Composite; 13) Ti + SWNT Composites: Thermal/Mechanical; 14) Ti + SWNT Composites: Tensile Strength; and 15) Nano-structured Shell for Pressure Vessels.

Self-sensing and thermal energy experimental characterization of multifunctional cement-matrix composites with carbon nano-inclusions

NASA Astrophysics Data System (ADS)

D'Alessandro, A.; Pisello, A. L.; Sambuco, Sara; Ubertini, F.; Asdrubali, F.; Materazzi, A. L.; Cotana, F.

2016-04-01

The recent progress of Nanotechnology allowed the development of new smart materials in several fields of engineering. In particular, innovative construction materials with multifunctional enhanced properties can be produced. The paper presents an experimental characterization on cement-matrix pastes doped with Carbon Nanotubes, Carbon Nano-fibers, Carbon Black and Graphene Nano-platelets. Both electro-mechanical and thermo-physical investigations have been carried out. The conductive nano-inclusions provide the cementitious matrix with piezo-resistive properties allowing the detection of external strain and stress changes. Thereby, traditional building materials, such as concrete and cementitious materials in general, would be capable of self-monitoring the state of deformation they are subject to, giving rise to diffuse sensing systems of structural integrity. Besides supplying self-sensing abilities, carbon nano-fillers may change mechanical, physical and thermal properties of cementitious composites. The experimental tests of the research have been mainly concentrated on the thermal conductivity and the optical properties of the different nano-modified materials, in order to make a critical comparison between them. The aim of the work is the characterization of an innovative multifunctional composite capable of combining self-monitoring properties with proper mechanical and thermal-energy efficiency characteristics. The potential applications of these nano-modified materials cover a wide range of possibilities, such as structural elements, floors, geothermal piles, radiant systems and more.

The effect of SiO 2-doped boron nitride multiple coatings on mechanical properties of quartz fibers

NASA Astrophysics Data System (ADS)

Zheng, Yu; Wang, Shubin

2012-01-01

SiO2-doped boron nitride multiple coatings (SiO2/BN multiple coatings) were prepared on quartz fibers surface at 700 °C. Single fiber tensile test was employed to evaluate fiber tensile strength; Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) were employed to evaluate morphology and structure of the fibers. Fiber tensile test results indicated that the strength of quartz fibers with SiO2/BN multiple coatings was about twice of the fibers with BN coatings and original fibers which were heated at 700 °C for 10 h. The SiO2/BN multiple coatings would provide compressive stress on quartz fibers, which would help to seal the defects on fiber surface. Furthermore, TEM images showed that the nano-SiO2 powders crystallized in advance of quartz fibers, which would suppress crystallization of quartz fibers and reduce damage from crystallization. Thus, nano-SiO2 powders would help to keep mechanical properties of quartz fibers.

Generation of nano roughness on fibrous materials by atmospheric plasma

NASA Astrophysics Data System (ADS)

Kulyk, I.; Scapinello, M.; Stefan, M.

2012-12-01

Atmospheric plasma technology finds novel applications in textile industry. It eliminates the usage of water and of hazard liquid chemicals, making production much more eco-friendly and economically convenient. Due to chemical effects of atmospheric plasma, it permits to optimize dyeing and laminating affinity of fabrics, as well as anti-microbial treatments. Other important applications such as increase of mechanical resistance of fiber sleeves and of yarns, anti-pilling properties of fabrics and anti-shrinking property of wool fabrics were studied in this work. These results could be attributed to the generation of nano roughness on fibers surface by atmospheric plasma. Nano roughness generation is extensively studied at different conditions. Alternative explanations for the important practical results on textile materials and discussed.

Development and characterization of powder metallurgically produced discontinuous tungsten fiber reinforced tungsten composites

NASA Astrophysics Data System (ADS)

Mao, Y.; Coenen, J. W.; Riesch, J.; Sistla, S.; Almanstötter, J.; Jasper, B.; Terra, A.; Höschen, T.; Gietl, H.; Bram, M.; Gonzalez-Julian, J.; Linsmeier, Ch; Broeckmann, C.

2017-12-01

In future fusion reactors, tungsten is the prime candidate material for the plasma facing components. Nevertheless, tungsten is prone to develop cracks due to its intrinsic brittleness—a major concern under the extreme conditions of fusion environment. To overcome this drawback, tungsten fiber reinforced tungsten (Wf/W) composites are being developed. These composite materials rely on an extrinsic toughing principle, similar to those in ceramic matrix composite, using internal energy dissipation mechanisms, such as crack bridging and fiber pull-out, during crack propagation. This can help Wf/W to facilitate a pseudo-ductile behavior and allows an elevated damage resilience compared to pure W. For pseudo-ductility mechanisms to occur, the interface between the fiber and matrix is crucial. Recent developments in the area of powder-metallurgical Wf/W are presented. Two consolidation methods are compared. Field assisted sintering technology and hot isostatic pressing are chosen to manufacture the Wf/W composites. Initial mechanical tests and microstructural analyses are performed on the Wf/W composites with a 30% fiber volume fraction. The samples produced by both processes can give pseudo-ductile behavior at room temperature.

Designing of Hybrid Structured Glass Laminated Transparent Nano Composites through Vacuum infusion Technique

NASA Astrophysics Data System (ADS)

Mukherji, A.; Tarapure, N. D.; Wakure, G. N.

2017-05-01

Glass is the most commonly used transparent material. However, glass is not suitable in applications where low weight, high strength is required. The present invention comprises a method of making a Transparent Glass Laminated Nano composite product. The product contains a Bidirectionally oriented E-Glass Fabric an essentially bidirectional yarn woven fabrics is stretched Bidirectionally by specially fabricated steel frame associated with both co and counter rotating device. These fibers include glass fibrics/cloths or mixtures of any of these. The synthetic fiber may be any synthetic silica based oven waived bi-directional or Uni-directional fabrics. Engaged gear provided in the device develops uniform tension on fabric, in both direction. Nano particle dispersed resin to be used is formulated with their respective curing agents and extenders. The formulated resin contains 0.1-0.5% of Nano additives and the product composed from 5-10 % of Glass fabric, between 10 to 20 % of ordinary glass, and between 60-80 % of the product is the Nano particles dispersed formulated resin, all measured by volume.

Electrospinning for nano- to mesoscale photonic structures

NASA Astrophysics Data System (ADS)

Skinner, Jack L.; Andriolo, Jessica M.; Murphy, John P.; Ross, Brandon M.

2017-08-01

The fabrication of photonic and electronic structures and devices has directed the manufacturing industry for the last 50 years. Currently, the majority of small-scale photonic devices are created by traditional microfabrication techniques that create features by processes such as lithography and electron or ion beam direct writing. Microfabrication techniques are often expensive and slow. In contrast, the use of electrospinning (ES) in the fabrication of micro- and nano-scale devices for the manipulation of photons and electrons provides a relatively simple and economic viable alternative. ES involves the delivery of a polymer solution to a capillary held at a high voltage relative to the fiber deposition surface. Electrostatic force developed between the collection plate and the polymer promotes fiber deposition onto the collection plate. Issues with ES fabrication exist primarily due to an instability region that exists between the capillary and collection plate and is characterized by chaotic motion of the depositing polymer fiber. Material limitations to ES also exist; not all polymers of interest are amenable to the ES process due to process dependencies on molecular weight and chain entanglement or incompatibility with other polymers and overall process compatibility. Passive and active electronic and photonic fibers fabricated through the ES have great potential for use in light generation and collection in optical and electronic structures/devices. ES produces fiber devices that can be combined with inorganic, metallic, biological, or organic materials for novel device design. Synergistic material selection and post-processing techniques are also utilized for broad-ranging applications of organic nanofibers that span from biological to electronic, photovoltaic, or photonic. As the ability to electrospin optically and/or electronically active materials in a controlled manner continues to improve, the complexity and diversity of devices fabricated from this

Mass production of polymer nano-wires filled with metal nano-particles.

PubMed

Lomadze, Nino; Kopyshev, Alexey; Bargheer, Matias; Wollgarten, Markus; Santer, Svetlana

2017-08-17

Despite the ongoing progress in nanotechnology and its applications, the development of strategies for connecting nano-scale systems to micro- or macroscale elements is hampered by the lack of structural components that have both, nano- and macroscale dimensions. The production of nano-scale wires with macroscale length is one of the most interesting challenges here. There are a lot of strategies to fabricate long nanoscopic stripes made of metals, polymers or ceramics but none is suitable for mass production of ordered and dense arrangements of wires at large numbers. In this paper, we report on a technique for producing arrays of ordered, flexible and free-standing polymer nano-wires filled with different types of nano-particles. The process utilizes the strong response of photosensitive polymer brushes to irradiation with UV-interference patterns, resulting in a substantial mass redistribution of the polymer material along with local rupturing of polymer chains. The chains can wind up in wires of nano-scale thickness and a length of up to several centimeters. When dispersing nano-particles within the film, the final arrangement is similar to a core-shell geometry with mainly nano-particles found in the core region and the polymer forming a dielectric jacket.

Process to produce silicon carbide fibers using a controlled concentration of boron oxide vapor

NASA Technical Reports Server (NTRS)

Barnard, Thomas Duncan (Inventor); Lipowitz, Jonathan (Inventor); Nguyen, Kimmai Thi (Inventor)

2001-01-01

A process for producing polycrystalline silicon carbide by heating an amorphous ceramic fiber that contains silicon and carbon in an environment containing boron oxide vapor. The boron oxide vapor is produced in situ by the reaction of a boron containing material such as boron carbide and an oxidizing agent such as carbon dioxide, and the amount of boron oxide vapor can be controlled by varying the amount and rate of addition of the oxidizing agent.

Process to produce silicon carbide fibers using a controlled concentration of boron oxide vapor

NASA Technical Reports Server (NTRS)

Barnard, Thomas Duncan (Inventor); Lipowitz, Jonathan (Inventor); Nguyen, Kimmai Thi (Inventor)

2000-01-01

A process for producing polycrystalline silicon carbide includes heating an amorphous ceramic fiber that contains silicon and carbon in an environment containing boron oxide vapor. The boron oxide vapor is produced in situ by the reaction of a boron containing material such as boron carbide and an oxidizing agent such as carbon dioxide, and the amount of boron oxide vapor can be controlled by varying the amount and rate of addition of the oxidizing agent.

Micro- and nano-CT textural analysis of an experimental volcanic fulgurite.

NASA Astrophysics Data System (ADS)

Cimarelli, Corrado; Yilmaz, Tim; Colombier, Mathieu; Villanova, Julie; Höfer, Lucas; Hess, Kai-Uwe; Ruthensteiner, Bernhard; Dingwell, Donald

2017-04-01

Fulgurites are natural glasses formed by cloud to ground lightning discharges causing rapid heating into rocks or unconsolidated sediments. Volcanic lightning can determine the re-melting and even ablation of newly formed or just deposited volcanic tephra during explosive eruptions. In this case the pristine material is already constituted by glass that can be further modified by the discharge. Although volcanic lightning discharges are generally less energetic than those produced by thunderclouds, the high temperatures reached by the lightning channel are well in excess of the low melting temperature of glass material. Here we have experimentally reproduced a fulgurite by single impulse voltage discharges (134 kV, 331 A, 10.5 J) on a target glass material. We have chosen borosilicate glass fibers (180 microns nominal length) as starting material to better account for the structural and chemical modification of the single particles after discharge-melting. The structure of the small fulgurite is best resolved through X-ray micro- and nano-computed tomography. Micro-CT analysis was carried out on a phoenix nanotom m with a voxelsize of 1 µm3. Additionally a 3D reconstruction with a voxel size of 150 nm3 has been analyzed at the new nano-analysis beamline ID16B at the ESRF. 3D analysis was carried out using Avizo 9.2 software, which allows non-destructive analysis of the fragile structure of the sample. The sample shows the channel-like structure typical for natural fulgurites with an inner void channel and internal wall constituted by the melted fibers. About 33% of the total solid volume of the fulgurite is melted to form the inner wall. The inner wall is characterized by nano- to micro-metric vesicles determined by volatile exsolution (mainly H2O) during the instantaneous heating and trapped in the low viscosity melt by the subsequent rapid quenching. Progressively outward the fulgurite shows the intricate delicate structure of the pristine glass fibers. Our

Ultrathin fiber poly-3-hydroxybutyrate, modified by silicon carbide nanoparticles

NASA Astrophysics Data System (ADS)

Olkhov, A. A.; Krutikova, A. A.; Goldshtrakh, M. A.; Staroverova, O. V.; Iordanskii, A. L.; Ischenko, A. A.

2016-11-01

The article presents the results of studies the composite fibrous material based on poly-3-hydroxybutyrate (PHB) and nano-size silicon carbide obtained by the electrospinning method. Size distribution of the silicon carbide nanoparticles in the fiber was estimated by X-ray diffraction technique. It is shown that immobilization of the SiC nanoparticles to the PHB fibers contributes to obtaining essentially smaller diameter of fibers, high physical-mechanical characteristics and increasing resistance to degradation in comparison with the fibers of PHB.

Miniature and low cost fiber Bragg grating interrogator for structural monitoring in nano-satellites

NASA Astrophysics Data System (ADS)

Toet, P. M.; Hagen, R. A. J.; Hakkesteegt, H. C.; Lugtenburg, J.; Maniscalco, M. P.

2017-11-01

In this paper we present a newly developed Fiber Optic measurement system, consisting of Fiber Bragg Grating (FBG) sensors and an FBG interrogator. The development of the measuring system is part of the PiezoElectric Assisted Smart Satellite Structure (PEASSS) project, which was initiated at the beginning of 2013 and is financed by the Seventh Framework Program (FP7) of the European Commission. Within the PEASSS project, a Nano-Satellite is being designed and manufactured to be equipped with new technology that will help keep Europe on the cutting edge of space research, potentially reducing the cost and development time for more accurate future sensor platforms including synthetic aperture optics, moving target detection and identification, and compact radars. After on ground testing the satellite is planned to be launched at the end of 2015. Within the satellite, different technologies will be demonstrated on orbit to show their capabilities for different in-space applications. For our application the FBG interrogator monitors the structural and thermal behaviour of a so called "smart panel". These panels will enable fine angle control and thermal and vibration compensation in order to improve all types of future Earth observations, such as environmental and planetary mapping, border and regional imaging. The Fiber Optic (FO) system in PEASSS includes four FBG strain sensors and two FBG temperature sensors. The 3 channel interrogator has to have a small footprint (110x50x40mm), is low cost, low in mass and has a low power consumption. In order to meet all these requirements, an interrogator has been designed based on a tunable Vertical-Cavity Surface-Emitting Laser (VCSEL) enabling a wavelength sweep of around 7 nm. To guarantee the absolute and relative performance, two reference methods are included internally in the interrogator. First, stabilized reference

Synthesis, Optical and Photoluminescence Properties of Cu-Doped Zno Nano-Fibers Thin Films: Nonlinear Optics

NASA Astrophysics Data System (ADS)

Ganesh, V.; Salem, G. F.; Yahia, I. S.; Yakuphanoglu, F.

2018-03-01

Different concentrations of copper-doped zinc oxide thin films were coated on a glass substrate by sol-gel/spin-coating technique. The structural properties of pure and Cu-doped ZnO films were characterized by different techniques, i.e., atomic force microscopy (AFM), photoluminescence and UV-Vis-NIR spectroscopy. The AFM study revealed that pure and doped ZnO films are formed as nano-fibers with a granular structure. The photoluminescence spectra of these films showed a strong ultraviolet emission peak centered at 392 nm and a strong blue emission peak cantered at 450 nm. The optical band gap of the pure and copper-doped ZnO thin films calculated from optical transmission spectra (3.29-3.23 eV) were found to be increasing with increasing copper doping concentration. The refractive index dispersion curve of pure and Cu-doped ZnO film obeyed the single-oscillator model. The optical dispersion parameters such as E o , E d , and n_{∞}2 were calculated. Further, the nonlinear refractive index and nonlinear optical susceptibility were also calculated and interpreted.

Nano-composite materials

DOEpatents

Lee, Se-Hee; Tracy, C. Edwin; Pitts, J. Roland

2010-05-25

Nano-composite materials are disclosed. An exemplary method of producing a nano-composite material may comprise co-sputtering a transition metal and a refractory metal in a reactive atmosphere. The method may also comprise co-depositing a transition metal and a refractory metal composite structure on a substrate. The method may further comprise thermally annealing the deposited transition metal and refractory metal composite structure in a reactive atmosphere.

Theranostic 3-Dimensional nano brain-implant for prolonged and localized treatment of recurrent glioma

NASA Astrophysics Data System (ADS)

Ramachandran, Ranjith; Junnuthula, Vijayabhaskar Reddy; Gowd, G. Siddaramana; Ashokan, Anusha; Thomas, John; Peethambaran, Reshmi; Thomas, Anoop; Unni, Ayalur Kodakara Kochugovindan; Panikar, Dilip; Nair, Shantikumar V.; Koyakutty, Manzoor

2017-03-01

Localized and controlled delivery of chemotherapeutics directly in brain-tumor for prolonged periods may radically improve the prognosis of recurrent glioblastoma. Here, we report a unique method of nanofiber by fiber controlled delivery of anti-cancer drug, Temozolomide, in orthotopic brain-tumor for one month using flexible polymeric nano-implant. A library of drug loaded (20 wt%) electrospun nanofiber of PLGA-PLA-PCL blends with distinct in vivo brain-release kinetics (hours to months) were numerically selected and a single nano-implant was formed by co-electrospinning of nano-fiber such that different set of fibres releases the drug for a specific periods from days to months by fiber-by-fiber switching. Orthotopic rat glioma implanted wafers showed constant drug release (116.6 μg/day) with negligible leakage into the peripheral blood (<100 ng) rendering ~1000 fold differential drug dosage in tumor versus peripheral blood. Most importantly, implant with one month release profile resulted in long-term (>4 month) survival of 85.7% animals whereas 07 day releasing implant showed tumor recurrence in 54.6% animals, rendering a median survival of only 74 days. In effect, we show that highly controlled drug delivery is possible for prolonged periods in orthotopic brain-tumor using combinatorial nanofibre libraries of bulk-eroding polymers, thereby controlling glioma recurrence.

Growth of periodic nano-layers of nano-crystals of Au, Ag, Cu by ion beam

NASA Technical Reports Server (NTRS)

Smith, Cydale C.; Zheng, B.; Muntele, C. I.; Muntele, I. C.; Ila, D.

2005-01-01

Multilayered thin films of SiO2/AU+ SiO2/, SiO2/Ag+ SiO2/, and SiO2/Cu+ SiO2/, were grown by deposition. We have previously shown that MeV ion Bombardment of multi-nano-layers of SiO2/AU+ SiO2/ produces Au nanocrystals in the AU+ SiO2 layers. An increased number of nano-layers followed by MeV ion bombardment produces a wide optical absorption band, of which its FWHM depends on the number of nano-layers of SiO2/AU+ SiO2/. We have successfully repeated this process for nano-layers of SiO2/Ag+ SiO2/, and SiO2/Cu+ SiO2/. In this work we used 5 MeV Si as the post deposition bombardment ion and monitored the location as well as the optical absorption's FWHM for each layered structure using Optical Absorption Photospectrometry. The concentration and location of the metal nano-crystals were measured by Rutherford Backscattering Spectrometry. We will report on the results obtained for nano-layered structures produced by post deposition bombardment of SiO2/AU+ SiO2/, SiO2/Ag+ SiO2/, and SiO2/Cu+ SiO2/ layered systems as well as the results obtained from a system containing a periodic combination of SiO2/AU+ SiO2/, SiO2/Ag+ SiO2/, and SiO2/Cu+ SiO2/.

The Challenge of Producing Fiber-Based Organic Electronic Devices

PubMed Central

Könyves-Toth, Tobias; Gassmann, Andrea; von Seggern, Heinz

2014-01-01

The implementation of organic electronic devices on fibers is a challenging task, not yet investigated in detail. As was shown earlier, a direct transition from a flat device structure to a fiber substrate is in principle possible. However, a more detailed investigation of the process reveals additional complexities than just the transition in geometry. It will be shown, that the layer formation of evaporated materials behaves differently due to the multi-angled incidence on the fibers surface. In order to achieve homogenous layers the evaporation process has to be adapted. Additionally, the fiber geometry itself facilitates damaging of its surface due to mechanical impact and leads to a high surface roughness, thereby often hindering commercial fibers to be used as substrates. In this article, a treatment of commercial polymer-coated glass fibers will be demonstrated that allows for the fabrication of rather flexible organic light-emitting diodes (OLEDs) with cylindrical emission characteristics. Since OLEDs rely the most on a smooth substrate, fibers undergoing the proposed treatment are applicable for other organic electronic devices such as transistors and solar cells. Finally, the technique also supports the future fabrication of organic electronics not only in smart textiles and woven electronics but also in bent surfaces, which opens a wide range of applications. PMID:28788128

Electric Power from Cryo (Nano) Ice

NASA Astrophysics Data System (ADS)

Kandasamy, A.; Chandran, M.

2017-05-01

In this paper, the authors have studied experimentally the performance of cryocooler which is a mechanical device for producing very low temperature with significant cooling capacity. Nano particles were administrated to enhance the faster rate of cooling. Electric power (energy) was produced from cryogenic (nano) ice with help of thermoelectric effect. The governing equations for energy conversions, cooling capacity, amount of electric power was also discussed.

Method of producing nano-scaled graphene and inorganic platelets and their nanocomposites

DOEpatents

Jang, Bor Z [Centerville, OH; Zhamu, Aruna [Centerville, OH

2011-02-22

Disclosed is a method of exfoliating a layered material (e.g., graphite and graphite oxide) to produce nano-scaled platelets having a thickness smaller than 100 nm, typically smaller than 10 nm, and often between 0.34 nm and 1.02 nm. The method comprises: (a) subjecting the layered material in a powder form to a halogen vapor at a first temperature above the melting point or sublimation point of the halogen at a sufficient vapor pressure and for a duration of time sufficient to cause the halogen molecules to penetrate an interlayer space of the layered material, forming a stable halogen-intercalated compound; and (b) heating the halogen-intercalated compound at a second temperature above the boiling point of the halogen, allowing halogen atoms or molecules residing in the interlayer space to exfoliate the layered material to produce the platelets. Alternatively, rather than heating, step (a) is followed by a step of dispersing the halogen-intercalated compound in a liquid medium which is subjected to ultrasonication for exfoliating the halogen-intercalated compound to produce the platelets, which are dispersed in the liquid medium. The halogen can be readily captured and re-used, thereby significantly reducing the impact of halogen to the environment. The method can further include a step of dispersing the platelets in a polymer or monomer solution or suspension as a precursor step to nanocomposite fabrication.

Method of producing nano-scaled graphene and inorganic platelets and their nanocomposites

DOEpatents

Jang, Bor Z [Centerville, OH; Zhamu, Aruna [Centerville, OH

2012-02-14

Disclosed is a method of exfoliating a layered material (e.g., graphite and graphite oxide) to produce nano-scaled platelets having a thickness smaller than 100 nm, typically smaller than 10 nm, and often between 0.34 nm and 1.02 nm. The method comprises: (a) subjecting the layered material in a powder form to a halogen vapor at a first temperature above the melting point or sublimation point of the halogen at a sufficient vapor pressure and for a duration of time sufficient to cause the halogen molecules to penetrate an interlayer space of the layered material, forming a stable halogen-intercalated compound; and (b) heating the halogen-intercalated compound at a second temperature above the boiling point of the halogen, allowing halogen atoms or molecules residing in the interlayer space to exfoliate the layered material to produce the platelets. Alternatively, rather than heating, step (a) is followed by a step of dispersing the halogen-intercalated compound in a liquid medium which is subjected to ultrasonication for exfoliating the halogen-intercalated compound to produce the platelets, which are dispersed in the liquid medium. The halogen can be readily captured and re-used, thereby significantly reducing the impact of halogen to the environment. The method can further include a step of dispersing the platelets in a polymer or monomer solution or suspension as a precursor step to nanocomposite fabrication.

Catalytic property of fiber media supported palladium containing alloy nanoparticles and electrospun ceramic fibers biodurability study

NASA Astrophysics Data System (ADS)

Shin, Hyeon Ung

The nanoscale of the supporting fibers may provide enhancements such as restricting the migration of metal catalyst particles. In this work, palladium nanoparticle doped alumina fibers were electrospun into template submicron fibers. These fibers were calcined at temperatures between 650°C and 1150°C to vary the crystal structures of the calcined fibers with the Pd particle size. Higher calcination temperatures led to higher reaction temperatures from 250 to about 450°C for total conversion, indicating the effective reactivity of the fiber-supported catalysts decreased with increase in calcination temperature. Pd-Au alloy nanoparticle doped titania fibers were also fabricated using an electrospinning method and assembled into a fibrous porous medium structure by a vacuum molding process. In reactor tests, the fiber media with Pd-Au alloy nanoparticle catalyst had greater reactivity in conversion of NO and CO gases than that of fiber media with Pd monometallic catalyst alone, attributed to a lower activation energy of the Pd-Au catalyst particles. In carbon monoxide oxidation reaction tests, the results showed that the performance was optimal for a catalyst of composition Pd2Au1 molar ratio that was active at 125°C, which had higher dispersion of active components and better catalytic performance compared to monometallic particle Au/TiO 2 and Pd/TiO2 fiber media. Moreover, the improved reaction activity of Pd2Au1/TiO2 fiber medium was attributed to a decreased in the activation energy. Further experiments were conducted using the electrospun ceramic fibers biodurability study. The properties of nano-sized fiber structures have attracted the attention of recent research on ceramic nanostructures as nonwoven media for applications in hazardous chemical and high temperature environments. However, health and safety concerns of micro and nano scale ceramic materials have not been fully investigated. Little is known about the physicochemical effects of the properties

Electrospun Polymer Fibers for Electronic Applications

PubMed Central

Luzio, Alessandro; Canesi, Eleonora Valeria; Bertarelli, Chiara; Caironi, Mario

2014-01-01

Nano- and micro- fibers of conjugated polymer semiconductors are particularly interesting both for applications and for fundamental research. They allow an investigation into how electronic properties are influenced by size confinement and chain orientation within microstructures that are not readily accessible within thin films. Moreover, they open the way to many applications in organic electronics, optoelectronics and sensing. Electro-spinning, the technique subject of this review, is a simple method to effectively form and control conjugated polymer fibers. We provide the basics of the technique and its recent advancements for the formation of highly conducting and high mobility polymer fibers towards their adoption in electronic applications. PMID:28788493

Ultra-low power, Zeno effect based optical modulation in a degenerate V-system with a tapered nano fiber in atomic vapor.

PubMed

Salit, K; Salit, M; Krishnamurthy, Subramanian; Wang, Y; Kumar, P; Shahriar, M S

2011-11-07

We demonstrate an ultra-low light level optical modulator using a tapered nano fiber embedded in a hot rubidium vapor. The control and signal beams are co-propagating but orthogonally polarized, leading to a degenerate V-system involving coherent superpositions of Zeeman sublevels. The modulation is due primarily to the quantum Zeno effect for the signal beam induced by the control beam. For a control power of 40 nW and a signal power of 100 pW, we observe near 100% modulation. The ultra-low power level needed for the modulation is due to a combination of the Zeno effect and the extreme field localization in the evanescent field around the taper.

Relevance of fiber integrated gelatin-nanohydroxyapatite composite scaffold for bone tissue regeneration

NASA Astrophysics Data System (ADS)

Halima Shamaz, Bibi; Anitha, A.; Vijayamohan, Manju; Kuttappan, Shruthy; Nair, Shantikumar; Nair, Manitha B.

2015-10-01

Porous nanohydroxyapatite (nanoHA) is a promising bone substitute, but it is brittle, which limits its utility for load bearing applications. To address this issue, herein, biodegradable electrospun microfibrous sheets of poly(L-lactic acid)-(PLLA)-polyvinyl alcohol (PVA) were incorporated into a gelatin-nanoHA matrix which was investigated for its mechanical properties, the physical integration of the fibers with the matrix, cell infiltration, osteogenic differentiation and bone regeneration. The inclusion of sacrificial fibers like PVA along with PLLA and leaching resulted in improved cellular infiltration towards the center of the scaffold. Furthermore, the treatment of PLLA fibers with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide enhanced their hydrophilicity, ensuring firm anchorage between the fibers and the gelatin-HA matrix. The incorporation of PLLA microfibers within the gelatin-nanoHA matrix reduced the brittleness of the scaffolds, the effect being proportional to the number of layers of fibrous sheets in the matrix. The proliferation and osteogenic differentiation of human adipose-derived mesenchymal stem cells was augmented on the fibrous scaffolds in comparison to those scaffolds devoid of fibers. Finally, the scaffold could promote cell infiltration, together with bone regeneration, upon implantation in a rabbit femoral cortical defect within 4 weeks. The bone regeneration potential was significantly higher when compared to commercially available HA (Surgiwear™). Thus, this biomimetic, porous, 3D composite scaffold could be offered as a promising candidate for bone regeneration in orthopedics.

Man-made vitreous fiber produced from incinerator ash using the thermal plasma technique and application as reinforcement in concrete.

PubMed

Yang, Sheng-Fu; Wang, To-Mai; Lee, Wen-Cheng; Sun, Kin-Seng; Tzeng, Chin-Ching

2010-10-15

This study proposes using thermal plasma technology to treat municipal solid waste incinerator ashes. A feasible fiberization method was developed and applied to produce man-made vitreous fiber (MMVF) from plasma vitrified slag. MMVF were obtained through directly blending the oxide melt stream with high velocity compressed air. The basic technological characteristics of MMVF, including morphology, diameter, shot content, length and chemical resistance, are described in this work. Laboratory experiments were conducted on the fiber-reinforced concrete. The effects of fibrous content on compressive strength and flexural strength are presented. The experimental results showed the proper additive of MMVF in concrete can enhance its mechanical properties. MMVF products produced from incinerator ashes treated with the thermal plasma technique have great potential for reinforcement in concrete. 2010 Elsevier B.V. All rights reserved.

Evanescent-wave photoacoustic spectroscopy with optical micro/nano fibers.

PubMed

Cao, Yingchun; Jin, Wei; Ho, Lut Hoi; Liu, Zhibo

2012-01-15

We demonstrate gas detection based on evanescent-wave photoacoustic (PA) spectroscopy with tapered optical fibers. Evanescent-field instead of open-path absorption is exploited for PA generation, and a quartz tuning fork is used for PA detection. A tapered optical fiber with a diameter down to the wavelength scale demonstrates detection sensitivity similar to an open-path system but with the advantages of easier optical alignment, smaller insertion loss, and multiplexing capability.

Fiber webs

Treesearch

Roger M. Rowell; James S. Han; Von L. Byrd

2005-01-01

Wood fibers can be used to produce a wide variety of low-density three-dimensional webs, mats, and fiber-molded products. Short wood fibers blended with long fibers can be formed into flexible fiber mats, which can be made by physical entanglement, nonwoven needling, or thermoplastic fiber melt matrix technologies. The most common types of flexible mats are carded, air...

Monitoring Fiber Stress During Curing of Single Fiber Glass- and Graphite-Epoxy Composites

NASA Technical Reports Server (NTRS)

Madhukar, Madhu S.; Kosuri, Ranga P.; Bowles, Kenneth J.

1994-01-01

The difference in thermal expansion characteristics of epoxy matrices and graphite fibers can produce significant residual stresses in the fibers during curing of composite materials. Tests on single fiber glass-epoxy and graphite-epoxy composite specimens were conducted in which the glass and graphite fibers were preloaded in tension, and the epoxy matrix was cast around the fibers. The fiber tension was monitored while the matrix was placed around the fiber and subjected to the temperature-time curing cycle. Two mechanisms responsible for producing stress in embedded fibers were identified as matrix thermal expansion and contraction and matrix cure shrinkage. A simple analysis based on the change in fiber tension during the curing cycle was conducted to estimate the produced stresses. Experimental results on single fiber glass- and graphite-epoxy composites show that the fiber was subjected to significant tensile stresses when the temperature was raised from the first to the second dwell period. When initial fiber pretension is about 60 percent of the fiber failure load, these curing-induced stresses can cause tensile fracture of the embedded fiber.

In Planta Synthesis of Designer-Length Tobacco Mosaic Virus-Based Nano-Rods That Can Be Used to Fabricate Nano-Wires.

PubMed

Saunders, Keith; Lomonossoff, George P

2017-01-01

We have utilized plant-based transient expression to produce tobacco mosaic virus (TMV)-based nano-rods of predetermined lengths. This is achieved by expressing RNAs containing the TMV origin of assembly sequence (OAS) and the sequence of the TMV coat protein either on the same RNA molecule or on two separate constructs. We show that the length of the resulting nano-rods is dependent upon the length of the RNA that possesses the OAS element. By expressing a version of the TMV coat protein that incorporates a metal-binding peptide at its C-terminus in the presence of RNA containing the OAS we have been able to produce nano-rods of predetermined length that are coated with cobalt-platinum. These nano-rods have the properties of defined-length nano-wires that make them ideal for many developing bionanotechnological processes.

In Planta Synthesis of Designer-Length Tobacco Mosaic Virus-Based Nano-Rods That Can Be Used to Fabricate Nano-Wires

PubMed Central

Saunders, Keith; Lomonossoff, George P.

2017-01-01

We have utilized plant-based transient expression to produce tobacco mosaic virus (TMV)-based nano-rods of predetermined lengths. This is achieved by expressing RNAs containing the TMV origin of assembly sequence (OAS) and the sequence of the TMV coat protein either on the same RNA molecule or on two separate constructs. We show that the length of the resulting nano-rods is dependent upon the length of the RNA that possesses the OAS element. By expressing a version of the TMV coat protein that incorporates a metal-binding peptide at its C-terminus in the presence of RNA containing the OAS we have been able to produce nano-rods of predetermined length that are coated with cobalt-platinum. These nano-rods have the properties of defined-length nano-wires that make them ideal for many developing bionanotechnological processes. PMID:28878782

The energy dissipative mechanisms of the particle-fiber interface in a textile composite

NASA Astrophysics Data System (ADS)

McAllister, Quinn Patrick

Impact resistant fabrics comprised of woven high performance fibers (e.g., Kevlar) have exhibited improved energy dissipative capability with the inclusion of nano- to micrometer sized particles. Upon impact, the particles embed and gouge adjacent fiber surfaces. While the particle-fiber interactions appear to be a primary mechanism for the increase in energy dissipation, the fundamentals of the nano- to micrometer sized gouging response of high performance fibers and the dissipation of energy due to particle gouging have not been studied previously. In this research, nanoindentation and nanoscratching techniques, which exploit probe sizes in the range of nano- to micrometers, were used to study the particle-fiber contact and develop nanoscale structure-property relationships of single Kevlar fibers. Atomic force microscopy based methods were used to create high resolution stiffness maps of fiber cross-sections, the results of which indicated that the stiffness of Kevlar 49 fibers is independent of radial position, while Kevlar KM2 fibers exhibit a reduced stiffness "shell" region (up to ˜300-350 nm thick). Instrumented indentation was used to evaluate the local response of Kevlar fibers with respect to orientation and contact size. For radial indentation, modifications to the traditional indentation analysis were developed to account for fiber curvature and finite size effects. A critical contact size was established above which the fiber response was independent of indenter size. This "homogeneous" response was used to estimate the local material properties of the Kevlar fibers through the application of an analytical model for indentation of a transversely isotropic material. The local properties of both fibers differed from their previously measured bulk properties, which was likely due, at least in part, to the deformation mechanisms of the fiber microstructure during indentation. Nanoindentation and nanoscratch tests were then conducted to study the

Novel high-strength biocomposites based on microfibrillated cellulose having nano-order-unit web-like network structure

NASA Astrophysics Data System (ADS)

Nakagaito, A. N.; Yano, H.

2005-01-01

A completely new kind of high-strength composite was manufactured using microfibrillated cellulose (MFC) derived from kraft pulp. Because of the unique structure of nano-order-scale interconnected fibrils and microfibrils greatly expanded in the surface area that characterizes MFC, it was possible to produce composites that exploit the extremely high strength of microfibrils. The Young’s modulus (E) and bending strength (σb) of composites using phenolic resin as binder achieved values up to 19 GPa and 370 MPa, respectively, with a density of 1.45 g/cm2, exhibiting outstanding mechanical properties for a plant-fiber-based composite.

A new class of boron nitride fibers with tunable properties by combining an electrospinning process and the polymer-derived ceramics route

NASA Astrophysics Data System (ADS)

Salles, Vincent; Bernard, Samuel; Brioude, Arnaud; Cornu, David; Miele, Philippe

2010-02-01

Novel boron nitride (BN) fibers have been developed with diameters ranging from the nano- to microscale by thermal conversion of as-electrospun fibers from polyacrylonitrile and poly[B-(methylamino)borazine] blend solutions. Such a new class of ceramic fibers is seen as potential candidate for thermal management applications and filtration systems in harsh environments.Novel boron nitride (BN) fibers have been developed with diameters ranging from the nano- to microscale by thermal conversion of as-electrospun fibers from polyacrylonitrile and poly[B-(methylamino)borazine] blend solutions. Such a new class of ceramic fibers is seen as potential candidate for thermal management applications and filtration systems in harsh environments. Electronic supplementary information (ESI) available: Experimental details and EDX results. See DOI: 10.1039/b9nr00185a

High aspect ratio template and method for producing same

NASA Technical Reports Server (NTRS)

Sakamoto, Jeff S. (Inventor); Weiss, James R. (Inventor); Fleurial, Jean-Pierre (Inventor); Kisor, Adam (Inventor); Tuszynski, Mark (Inventor); Stokols, Shula (Inventor); Holt, Todd Edward (Inventor); Welker, David James (Inventor); Breckon, Christopher David (Inventor)

2010-01-01

Millimeter to nano-scale structures manufactured using a multi-component polymer fiber matrix are disclosed. The use of dissimilar polymers allows the selective dissolution of the polymers at various stages of the manufacturing process. In one application, biocompatible matrixes may be formed with long pore length and small pore size. The manufacturing process begins with a first polymer fiber arranged in a matrix formed by a second polymer fiber. End caps may be attached to provide structural support and the polymer fiber matrix selectively dissolved away leaving only the long polymer fibers. These may be exposed to another product, such as a biocompatible gel to form a biocompatible matrix. The polymer fibers may then be selectively dissolved leaving only a biocompatible gel scaffold with the pores formed by the dissolved polymer fibers.

High fiber-low matrix composites: kenaf fiber/polypropylene.

Treesearch

Anand R. Sanadi; J.F. Hunt; D.F. Caulfield; G. Kovacsvolgyi; B. Destree

2002-01-01

Considerable interest has been generated in the use of lignocellulosic fibers and wastes (both agricultural and wood based) as fillers and reinforcements in thermoplastics. In general, present technologies limit fiber loading in thermoplastics to about 60 percent by weight of fiber. To produce high fiber content composites for commercial use while maintaining adequate...

The intense slow positron beam facility at the PULSTAR reactor and applications in nano-materials study

NASA Astrophysics Data System (ADS)

Liu, Ming; Moxom, Jeremy; Hawari, Ayman I.; Gidley, David W.

2013-04-01

An intense slow positron beam has been established at the PULSTAR nuclear research reactor of North Carolina State University. The slow positrons are generated by pair production in a tungsten moderator from gammarays produced in the reactor core and by neutron capture reactions in cadmium. The moderated positrons are electrostatically extracted and magnetically guided out of the region near the core. Subsequently, the positrons are used in two spectrometers that are capable of performing positron annihilation lifetime spectroscopy (PALS) and positron Doppler broadening spectroscopy (DBS) to probe the defect and free volume properties of materials. One of the spectrometers (e+-PALS) utilizes an rf buncher to produce a pulsed beam and has a timing resolution of 277 ps. The second spectrometer (Ps-PALS) uses a secondary electron timing technique and is dedicated to positronium lifetime measurements with an approximately 1 ns timing resolution. PALS measurements have been conducted in the e+-PALS spectrometer on a series of nano-materials including organic photovoltaic thin films, membranes for filtration, and polymeric fibers. These studies have resulted in understanding some critical issues related to the development of the examined nano-materials.

Demodulation algorithm for optical fiber F-P sensor.

PubMed

Yang, Huadong; Tong, Xinglin; Cui, Zhang; Deng, Chengwei; Guo, Qian; Hu, Pan

2017-09-10

The demodulation algorithm is very important to improving the measurement accuracy of a sensing system. In this paper, the variable step size hill climbing search method will be initially used for the optical fiber Fabry-Perot (F-P) sensing demodulation algorithm. Compared with the traditional discrete gap transformation demodulation algorithm, the computation is greatly reduced by changing step size of each climb, which could achieve nano-scale resolution, high measurement accuracy, high demodulation rates, and large dynamic demodulation range. An optical fiber F-P pressure sensor based on micro-electro-mechanical system (MEMS) has been fabricated to carry out the experiment, and the results show that the resolution of the algorithm can reach nano-scale level, the sensor's sensitivity is about 2.5  nm/KPa, which is similar to the theoretical value, and this sensor has great reproducibility.

Carbon fibers with a nano-hydroxyapatite coating as an excellent biofilm support for bioreactors

NASA Astrophysics Data System (ADS)

Liu, Qijie; Zhang, Chao; Bao, Yanling; Dai, Guangze

2018-06-01

A biofilm support with high biocompatibility is needed for bioreactors. A nano-hydroxyapatite (HA) coating on carbon fibers (CFs) was prepared by electrochemical deposition (ECD). The sludge immobilization assays, bacterial cells adhesion assays and Derjaguin-Landau-Verwey-Overbeek (DLVO) theory were used to evaluate the capacity of CF supports to immobilize activated sludge and bacterial cells. The sludge immobilization and bacterial cells adhesion assays illustrated that HA coating could enhance the capacity of CFs to immobilize microorganisms. SEM images showed that HA and bacterial cells formed a dense film on CFs surface. In addition, HA, acting as a glue, could combine CFs with bacterial cells or between cells, which helped CFs capture more bacterial cells. DLVO theory illustrated that CFs with HA coating had a lower total interaction energy than CFs without handling, explaining the higher capacity of CFs with HA coating to immobilize bacterial cells. This result was owning to the less negative zeta potential and higher hydrophilicity of CFs with HA coating, and the hydrophilicity made a greater contribution to the lower total interaction energy. Experiments and theory reveal that HA coating could enhance the biocompatibility of CFs, and CFs with HA coating could be used as an excellent biofilm support for bioreactors.

Radiation-hardened nano-particles-based Erbium-doped fiber for space environment

NASA Astrophysics Data System (ADS)

Thomas, Jérémie; Myara, Mikhaël.; Signoret, Philippe; Burov, Ekaterina; Pastouret, Alain; Melin, Gilles; Boivin, David; Gilard, Olivier; Sotom, Michel

2017-11-01

We demonstrate for the first time a radiationresistant Erbium-Doped Fiber exhibiting performances that can fill the requirements of Erbium-Doped Fiber Amplifiers for space applications. This is based on an Aluminum co-doping atom reduction enabled by Nanoparticules Doping-Process. For this purpose, we developed several fibers containing very different erbium and aluminum concentrations, and tested them in the same optical amplifier configuration. This work allows to bring to the fore a highly radiation resistant Erbium-doped pure silica optical fiber exhibiting a low quenching level. This result is an important step as the EDFA is increasingly recognized as an enabling technology for the extensive use of photonic sub-systems in future satellites.

Method of microbially producing metal gallate spinel nano-objects, and compositions produced thereby

DOE Office of Scientific and Technical Information (OSTI.GOV)

Duty, Chad E.; Jellison, Jr., Gerald E.; Love, Lonnie J.

A method of forming a metal gallate spinel structure that includes mixing a divalent metal-containing salt and a gallium-containing salt in solution with fermentative or thermophilic bacteria. In the process, the bacteria nucleate metal gallate spinel nano-objects from the divalent metal-containing salt and the gallium-containing salt without requiring reduction of a metal in the solution. The metal gallate spinel structures, as well as light-emitting structures in which they are incorporated, are also described.

Fabrication of a Nano-ZnO/Polyethylene/Wood-Fiber Composite with Enhanced Microwave Absorption and Photocatalytic Activity via a Facile Hot-Press Method

PubMed Central

Dang, Baokang; Chen, Yipeng; Shen, Xiaoping; Chen, Bo; Sun, Qingfeng; Jin, Chunde

2017-01-01

A polyethylene/wood-fiber composite loaded with nano-ZnO was prepared by a facile hot-press method and was used for the photocatalytic degradation of organic compounds as well as for microwave absorption. ZnO nanoparticles with an average size of 29 nm and polyethylene (PE) powders were dispersed on the wood fibers’ surface through a viscous cationic polyacrylamide (CPAM) solution. The reflection loss (RL) value of the resulting composite was −21 dB, with a thickness of 3.5 mm in the frequency of 17.17 GHz. The PE/ZnO/wood-fiber (PZW) composite exhibited superior photocatalytic activity (84% methyl orange degradation within 300 min) under UV light irradiation. ZnO nanoparticels (NPs) increased the storage modulus of the PZW composite, and the damping factor was transferred to the higher temperature region. The PZW composite exhibited the maximum flexural strength of 58 MPa and a modulus of elasticity (MOE) of 9625 MPa. Meanwhile, it also displayed dimensional stability (thickness swelling value of 9%). PMID:29099777

Structural and Morphological Evaluation of Nano-Sized MoSi2 Powder Produced by Mechanical Milling

NASA Astrophysics Data System (ADS)

Sameezadeh, Mahmood; Farhangi, Hassan; Emamy, Masoud

Nano-sized intermetallic powders have received great attention owing to their property advantages over conventional micro-sized counterparts. In the present study nano-sized MoSi2 powder has been produced successfully from commercially available MoSi2 (3 μm) by a mechanical milling process carried out for a period of 100 hours. The effects of milling time on size and morphology of the powders were studied by SEM and TEM and image analyzing system. The results indicate that the as-received micrometric powder with a wide size distribution of irregular shaped morphology changes to a narrow size distribution of nearly equiaxed particles with the progress of attrition milling up to 100 h, reaching an average particle size of 71 nm. Structural evolution of milled samples was characterized by XRD to determine the crystallite size and lattice microstrain using Williamson-Hall method. According to the results, the crystallite size of the powders decreases continuously down to 23 nm with increasing milling time up to 100 h and this size refinement is more rapid at the early stages of the milling process. On the other hand, the lattice strain increases considerably with milling up to 65 h and further milling causes no significant changes of lattice strain.

Nano-structured wild moth cocoon fibers as radiative cooling and waveguiding optical materials

NASA Astrophysics Data System (ADS)

Shi, Norman Nan; Tsai, Cheng-Chia; Bernard, Gary D.; Craig, Catherine; Yu, Nanfang

2017-09-01

The study shows that comet moth cocoon fibers exhibit radiative cooing properties with enhanced solar reflectivity and thermal emissivity. Nanostructured voids inside the cocoon fiber enables the cocoons to exhibit strong scattering in the visible and near-infrared. These structures also allow the fibers to exhibit strong shape birefringence and directional reflectivity. Optical waveguiding due to transverse Anderson localization is observed in these natural fibers, where the invariance and large concentration of the voids in the longitudinal direction allow the fiber to confine light in the transverse direction. To mimic the optical effects generated by these natural silk fibers, nanostructured voids are introduced into regenerated silk fibers through wet spinning to enhance reflectivity in the solar spectrum.

Process of making titanium carbide (TiC) nano-fibrous felts

DOEpatents

Fong, Hao; Zhang, Lifeng; Zhao, Yong; Zhu, Zhengtao

2015-01-13

A method of synthesizing mechanically resilient titanium carbide (TiC) nanofibrous felts comprising continuous nanofibers or nano-ribbons with TiC crystallites embedded in carbon matrix, comprising: (a) electrospinning a spin dope for making precursor nanofibers with diameters less than 0.5 J.Lm; (b) overlaying the nanofibers to produce a nanofibrous mat (felt); and then (c) heating the nano-felts first at a low temperature, and then at a high temperature for making electrospun continuous nanofibers or nano-ribbons with TiC crystallites embedded in carbon matrix; and (d) chlorinating the above electrospun nano-felts at an elevated temperature to remove titanium for producing carbide derived carbon (CDC) nano-fibrous felt with high specific surface areas.

Synthesis of Nano-Crystalline Gamma-TiAl Materials

NASA Technical Reports Server (NTRS)

Hales, Stephen J.; Vasquez, Peter

2003-01-01

One of the principal problems with nano-crystalline materials is producing them in quantities and sizes large enough for valid mechanical property evaluation. The purpose of this study was to explore an innovative method for producing nano-crystalline gamma-TiAl bulk materials using high energy ball milling and brief secondary processes. Nano-crystalline powder feedstock was produced using a Fritsch P4(TM) vario-planetary ball mill recently installed at NASA-LaRC. The high energy ball milling process employed tungsten carbide tooling (vials and balls) and no process control agents to minimize contamination. In a collaborative effort, two approaches were investigated, namely mechanical alloying of elemental powders and attrition milling of pre-alloyed powders. The objective was to subsequently use RF plasma spray deposition and short cycle vacuum hot pressing in order to effect consolidation while retaining nano-crystalline structure in bulk material. Results and discussion of the work performed to date are presented.

Damping behavior of nano-fibrous composites with viscous interface in anti-plane shear

NASA Astrophysics Data System (ADS)

Wang, Xu

2017-06-01

By using the composite cylinder assemblage model, we derive an explicit expression of the specific damping capacity of nano-fibrous composite with viscous interface when subjected to time-harmonic anti-plane shear loads. The fiber and the matrix are first endowed with separate and distinct Gurtin-Murdoch surface elasticities, and rate-dependent sliding occurs on the fiber-matrix interface. Our analysis indicates that the effective damping of the composite depends on five dimensionless parameters: the fiber volume fraction, the stiffness ratio, two parameters arising from surface elasticity and one parameter due to interface sliding.

Trends in polymeric electrospun fibers and their use as oral biomaterials.

PubMed

Meireles, Agnes B; Corrêa, Daniella K; da Silveira, João Vw; Millás, Ana Lg; Bittencourt, Edison; de Brito-Melo, Gustavo Ea; González-Torres, Libardo A

2018-05-01

Electrospinning is one of the techniques to produce structured polymeric fibers in the micro or nano scale and to generate novel materials for biomedical proposes. Electrospinning versatility provides fibers that could support different surgical and rehabilitation treatments. However, its diversity in equipment assembly, polymeric materials, and functional molecules to be incorporated in fibers result in profusion of recent biomaterials that are not fully explored, even though the recognized relevance of the technique. The present article describes the main electrospun polymeric materials used in oral applications, and the main aspects and parameters of the technique. Natural and synthetic polymers, blends, and composites were identified from the available literature and recent developments. Main applications of electrospun fibers were focused on drug delivery systems, tissue regeneration, and material reinforcement or modification, although studies require further investigation in order to enable direct use in human. Current and potential usages as biomaterials for oral applications must motivate the development in the use of electrospinning as an efficient method to produce highly innovative biomaterials, over the next few years. Impact statement Nanotechnology is a challenge for many researchers that look for obtaining different materials behaviors by modifying characteristics at a very low scale. Thus, the production of nanostructured materials represents a very important field in bioengineering, in which the electrospinning technique appears as a suitable alternative. This review discusses and provides further explanation on this versatile technique to produce novel polymeric biomaterials for oral applications. The use of electrospun fibers is incipient in oral areas, mainly because of the unfamiliarity with the technique. Provided disclosure, possibilities and state of the art are aimed at supporting interested researchers to better choose proper materials

Potassium methyl siliconate-treated pulp fibers and their effects on wood plastic composites: Water sorption and dimensional stability

Treesearch

Cheng Piao; Zhiyong Cai; Nicole M. Stark; Charles J. Monlezun

2013-01-01

Potassium methyl siliconate (PMS) was investigated as a new nano modifier of wood fiber and wood flour to improve the compatibility between the fiber/flour and the plastic matrix in fiber reinforced plastic composites. Before injection molding, bleached and brown pulp fibers and mixed species wood flour were pretreated in PMS solutions. The morphology of the treated...

Rheological Behavior of Tomato Fiber Suspensions Produced by High Shear and High Pressure Homogenization and Their Application in Tomato Products

PubMed Central

Sun, Ping; Adhikari, Benu P.; Li, Dong

2018-01-01

This study investigated the effects of high shear and high pressure homogenization on the rheological properties (steady shear viscosity, storage and loss modulus, and deformation) and homogeneity in tomato fiber suspensions. The tomato fiber suspensions at different concentrations (0.1%–1%, w/w) were subjected to high shear and high pressure homogenization and the morphology (distribution of fiber particles), rheological properties, and color parameters of the homogenized suspensions were measured. The homogenized suspensions were significantly more uniform compared to unhomogenized suspension. The homogenized suspensions were found to better resist the deformation caused by external stress (creep behavior). The apparent viscosity and storage and loss modulus of homogenized tomato fiber suspension are comparable with those of commercial tomato ketchup even at the fiber concentration as low as 0.5% (w/w), implying the possibility of using tomato fiber as thickener. The model tomato sauce produced using tomato fiber showed desirable consistency and color. These results indicate that the application of tomato fiber in tomato-based food products would be desirable and beneficial. PMID:29743890

Mechanical, physical and tribological characterization of nano-cellulose fibers reinforced bio-epoxy composites: An attempt to fabricate and scale the 'Green' composite.

PubMed

Barari, Bamdad; Omrani, Emad; Dorri Moghadam, Afsaneh; Menezes, Pradeep L; Pillai, Krishna M; Rohatgi, Pradeep K

2016-08-20

The development of bio-based composites is essential in order to protect the environment while enhancing energy efficiencies. In the present investigation, the plant-derived cellulose nano-fibers (CNFs)/bio-based epoxy composites were manufactured using the Liquid Composite Molding (LCM) process. More specifically, the CNFs with and without chemical modification were utilized in the composites. The curing kinetics of the prepared composites was studied using both the isothermal and dynamic Differential Scanning Calorimetry (DSC) methods. The microstructure as well as the mechanical and tribological properties were investigated on the cured composites in order to understand the structure-property correlations of the composites. The results indicated that the manufactured composites showed improved mechanical and tribological properties when compared to the pure epoxy samples. Furthermore, the chemically modified CNFs reinforced composites outperformed the untreated composites. The surface modification of the fibers improved the curing of the resin by reducing the activation energy, and led to an improvement in the mechanical properties. The CNFs/bio-based epoxy composites form uniform tribo-layer during sliding which minimizes the direct contact between surfaces, thus reducing both the friction and wear of the composites. Copyright © 2016 Elsevier Ltd. All rights reserved.

Hydrophobic-modified nano-cellulose fiber/PLA biodegradable composites for lowering water vapor transmission rate (WVTR) of paper.

PubMed

Song, Zhaoping; Xiao, Huining; Zhao, Yi

2014-10-13

New biodegradable nanocomposites have been successfully prepared by incorporating modified nano-cellulose fibers (NCF) in a biodegradable polylactic acid (PLA) matrix in this work. The hydrophobic-modified NCF was obtained by grafting hydrophobic monomers on NCF to improve the compatibility between NCF and PLA during blending. The resulting NCF/PLA composites were then applied on paper surface via a cast-coating process in an attempt to reduce the water vapor transmission rate (WVTR) of paper. The WVTR tests, conducted under various testing conditions and with different coating weights, demonstrated that the modified NCF/PLA composites coating played a critical role in lowering WVTR of paper. The lowest WVTR value was 34 g/m(2)/d, which was obtained with an addition of 1% of modified NCF to PLA and the composites coating weight at 40 g/m(2) and substantially lower than the control value at 1315 g/m(2)/d. The paper coated with the modified biodegradable composite is promising as green-based packaging materials. Copyright © 2014 Elsevier Ltd. All rights reserved.

Comparison between Single-Walled CNT, Multi-Walled CNT, and Carbon Nanotube-Fiber Pyrograf III

NASA Astrophysics Data System (ADS)

Mousa, Marwan S.

2018-02-01

Single-Walled CNT (SWCNTs), Multi-walled Carbon Nanotubes (MWCNTs), and Carbon Nanotube-Fibers Pyrograf III PR-1 (CNTFs) were deposited by chemical vapor deposition under vacuum pressure value of (10-7mbar). Their structures were investigated by field emission microscopy. Carbon Nano-Fibers Pyrograf III PR-1 showed an average fiber diameter within the range of 100-200 nm and a length of (30-100) μm. Single-walled Carbon Nanotubes were produced by high-pressure Carbon Monoxide process with an average diameter ranging between (1-4) nm and a length of (1-3) μm. Thin Multiwall Carbon Nanotube of carbon purity (90%) showed an average diameter tube (9.5 nm) with a high-aspect-ratio (>150). The research work reported here includes the field electron emission current-voltage (I-V) characteristics and presented as Fowler-Nordheim (FN) plots and the spatial emission current distributions (electron emission images) obtained and analyzed in terms of electron source features. For the three types of emitters, a single spot pattern for the electron spatial; distributions were observed, with emission current fluctuations in some voltage region.

Fiber pulling apparatus modification

NASA Technical Reports Server (NTRS)

Smith, Guy A.; Workman, Gary L.

1992-01-01

A reduced gravity fiber pulling apparatus (FPA) was constructed in order to study the effects of gravity on glass fiber formation. The apparatus was specifically designed and built for use on NASA's KC-135 aircraft. Four flights have been completed to date during which E-glass fiber was successfully produced in simulated zero, high, and lunar gravity environments. In addition simulated lunar soil samples were tested for their fiber producing properties using the FPA.

A nanodiamond-tapered fiber system with high single-mode coupling efficiency.

PubMed

Schröder, Tim; Fujiwara, Masazumi; Noda, Tetsuya; Zhao, Hong-Quan; Benson, Oliver; Takeuchi, Shigeki

2012-05-07

We present a fiber-coupled diamond-based single photon system. Single nanodiamonds containing nitrogen vacancy defect centers are deposited on a tapered fiber of 273 nanometer in diameter providing a record-high number of 689,000 single photons per second from a defect center in a single-mode fiber. The system can be cooled to cryogenic temperatures and coupled evanescently to other nanophotonic structures, such as microresonators. The system is suitable for integrated quantum transmission experiments, two-photon interference, quantum-random-number generation and nano-magnetometry.

Nano-encapsulation of fish oil in nano-liposomes and its application in fortification of yogurt.

PubMed

Ghorbanzade, Tahere; Jafari, Seid Mahdi; Akhavan, Sahar; Hadavi, Roxana

2017-02-01

Fish oils have many dietary benefits, but due to their strong odors and rapid deterioration, their application in food formulations is limited. For these reasons, nano-liposome was used to nano-encapsulate fish oil in this study and encapsulated fish oil was utilized in fortifying yogurt. Physicochemical properties of produced yogurt including pH, acidity, syneresis, fatty acid composition, peroxide value as well as sensory tests were investigated during three weeks storage at 4°C. Nano-liposome encapsulation resulted in a significant reduction in acidity, syneresis and peroxide value. The results of gas chromatography analyses revealed that after 21days storage, yogurt fortified with nano-encapsulated fish oil had a higher DHA and EPA contents than yogurt containing free fish oil. Overall, the results of this study indicates that adding nano-encapsulated fish oil into yogurt gave closer characteristics to control sample in terms of sensory characteristics than yogurt fortified with free fish oil. Copyright © 2016 Elsevier Ltd. All rights reserved.

System to continuously produce carbon fiber via microwave assisted plasma processing

DOEpatents

White, Terry L; Paulauskas, Felix L; Bigelow, Timothy S

2014-03-25

A method for continuously processing carbon fiber including establishing a microwave plasma in a selected atmosphere contained in an elongated chamber having a microwave power gradient along its length defined by a lower microwave power at one end and a higher microwave power at the opposite end of the elongated chamber. The elongated chamber having an opening in each of the ends of the chamber that are adapted to allow the passage of the fiber tow while limiting incidental gas flow into or out of said chamber. A continuous fiber tow is introduced into the end of the chamber having the lower microwave power. The fiber tow is withdrawn from the opposite end of the chamber having the higher microwave power. The fiber to is subjected to progressively higher microwave energy as the fiber is being traversed through the elongated chamber.

Efficient high-harmonic generation from a stable and compact ultrafast Yb-fiber laser producing 100 μJ, 350 fs pulses based on bendable photonic crystal fiber

NASA Astrophysics Data System (ADS)

Feehan, James S.; Price, Jonathan H. V.; Butcher, Thomas J.; Brocklesby, William S.; Frey, Jeremy G.; Richardson, David J.

2017-01-01

The development of an Yb3+-fiber-based chirped-pulse amplification system and the performance in the generation of extreme ultraviolet (EUV) radiation by high-harmonic generation is reported. The fiber laser produced 100 μJ, 350 fs output pulses with diffraction-limited beam quality at a repetition rate of 16.7 kHz. The system used commercial single-mode, polarization maintaining fiber technology. This included a 40 μm core, easily packaged, bendable final amplifier fiber in order to enable a compact system, to reduce cost, and provide reliable and environmentally stable long-term performance. The system enabled the generation of 0.4 μW of EUV at wavelengths between 27 and 80 nm with a peak at 45 nm using xenon gas. The EUV flux of 1011 photons per second for a driving field power of 1.67 W represents state-of-the-art generation efficiency for single-fiber amplifier CPA systems, corresponding to a maximum calculated energy conversion efficiency of 2.4 × 10-7 from the infrared to the EUV. The potential for high average power operation at increased repetition rates and further suggested technical improvements are discussed. Future applications could include coherent diffractive imaging in the EUV, and high-harmonic spectroscopy.

Characteristics of ADC12/nano Al2O3composites with Addition of Ti Produced By Stir Casting Method

NASA Astrophysics Data System (ADS)

Zulfia, A.; Krisiphala; Ferdian, D.; Utomo, B. W.; Dhaneswara, D.

2018-03-01

The mechanical properties and microstructure of ADC12/nano Al2O3 matrix composites have been studied in this work. The composites were produced by stir casting method. ADC 12 as matrix composites was combined by Mg and Ti. The addition of Ti was varied from 0.02 to 0.08 wt-% as grain refinement wetting to improve mechanical properties such as tensile strength, hardness and wear resistance, while Mg addition was to promote wetting between ADC 12 and nano Al2O3. The optimum tensile strength was found at 0.04 wt-% addition of Ti with value of 132.5 MPa, further adding more Ti cause a poisoning mechanism that will hindered the grain refining process and reduce the tensile strength. The hardness and wear resistance of composites would also increase because of the refinement process. and the added Magnesium in the material that will form Mg2Si primary phases who have a high hardness value.

An oral absorbent, surface-deacetylated chitin nano-fiber ameliorates renal injury and oxidative stress in 5/6 nephrectomized rats.

PubMed

Anraku, Makoto; Tabuchi, Ryo; Ifuku, Shinsuke; Nagae, Tomone; Iohara, Daisuke; Tomida, Hisao; Uekama, Kaneto; Maruyama, Toru; Miyamura, Shigeyuki; Hirayama, Fumitoshi; Otagiri, Masaki

2017-04-01

In this study, we report that surface-deacetylated chitin nano-fibers (SDACNFs) are more effective in decreasing renal injury and oxidative stress than deacetylated chitin powder (DAC) in 5/6 nephrectomized rats. An oral administration of low doses of SDACNFs (40mg/kg/day) over a 4 week period resulted in a significant decrease in serum indoxyl sulfate, creatinine and urea nitrogen levels, compared with a similar treatment with DAC or AST-120. The SDACNFs treatment also resulted in an increase in antioxidant potential, compared with that for DAC or AST-120. Immunohistochemical analyses also demonstrated that SDACNFs treated CRF rats showed a decrease in the amount of accumulated 8-OHdG compared with the CRF group. These results suggest that the ingestion of SDCH-NF results in a significant reduction in the levels of pro-oxidants, such as uremic toxins, in the gastrointestinal tract, thereby inhibiting the subsequent development of oxidative stress in the systemic circulation. Copyright © 2016. Published by Elsevier Ltd.

Nanomaterials for Functional Textiles and Fibers.

PubMed

Rivero, Pedro J; Urrutia, Aitor; Goicoechea, Javier; Arregui, Francisco J

2015-12-01

Nanoparticles are very interesting because of their surface properties, different from bulk materials. Such properties make possible to endow ordinary products with new functionalities. Their relatively low cost with respect to other nano-additives make them a promising choice for industrial mass-production systems. Nanoparticles of different kind of materials such as silver, titania, and zinc oxide have been used in the functionalization of fibers and fabrics achieving significantly improved products with new macroscopic properties. This article reviews the most relevant approaches for incorporating such nanoparticles into synthetic fibers used traditionally in the textile industry allowing to give a solution to traditional problems for textiles such as the microorganism growth onto fibers, flammability, robustness against ultraviolet radiation, and many others. In addition, the incorporation of such nanoparticles into special ultrathin fibers is also analyzed. In this field, electrospinning is a very promising technique that allows the fabrication of ultrathin fiber mats with an extraordinary control of their structure and properties, being an ideal alternative for applications such as wound healing or even functional membranes.

Nanomaterials for Functional Textiles and Fibers

NASA Astrophysics Data System (ADS)

Rivero, Pedro J.; Urrutia, Aitor; Goicoechea, Javier; Arregui, Francisco J.

2015-12-01

Nanoparticles are very interesting because of their surface properties, different from bulk materials. Such properties make possible to endow ordinary products with new functionalities. Their relatively low cost with respect to other nano-additives make them a promising choice for industrial mass-production systems. Nanoparticles of different kind of materials such as silver, titania, and zinc oxide have been used in the functionalization of fibers and fabrics achieving significantly improved products with new macroscopic properties. This article reviews the most relevant approaches for incorporating such nanoparticles into synthetic fibers used traditionally in the textile industry allowing to give a solution to traditional problems for textiles such as the microorganism growth onto fibers, flammability, robustness against ultraviolet radiation, and many others. In addition, the incorporation of such nanoparticles into special ultrathin fibers is also analyzed. In this field, electrospinning is a very promising technique that allows the fabrication of ultrathin fiber mats with an extraordinary control of their structure and properties, being an ideal alternative for applications such as wound healing or even functional membranes.

The therapeutic effect of nano-encapsulated and nano-emulsion forms of carvacrol on experimental liver fibrosis.

PubMed

Hussein, Jihan; El-Banna, Mona; Mahmoud, Khaled F; Morsy, Safaa; Abdel Latif, Yasmin; Medhat, Dalia; Refaat, Eman; Farrag, Abdel Razik; El-Daly, Sherien M

2017-06-01

The present study aimed to compare the therapeutic efficiency of nano-encapsulated and nano-emulsion carvacrol administration on liver injury in thioacetamide (TAA) treated rats. To fulfill our target, we used sixty male albino rats classified into six groups as follow: control, nano-encapsulated carvacrol, nano-emulsion carvacrol, thioacetamide, treated nano-encapsulated carvacrol and treated nano-emulsion carvacrol groups. Blood samples were collected from all groups and the separated serum was used for analysis of the following biochemical parameters; aspartate aminotransferase (AST), alanine aminotransferase (ALT), S100 B protein, alpha fetoprotein (AFP) and caspase-3. The levels of malondialdehyde (MDA), reduced glutathione (GSH), nitric oxide (NO), monocyte chemoattractant protein-1(MCP-1) and hydroxyproline content were all evaluated in liver tissue homogenate. Histopathological examinations for liver tissues were also performed. Thioacetamide induced hepatic damage in rats as revealed by the significant increase in the levels of serum ALT, AST and produced oxidative stress as displayed by the significant elevation in the levels of hepatic MDA and NO concomitant with a significant decrease in GSH. In addition, thioacetamide significantly increased serum S100B protein, alpha fetoprotein and caspase-3 along with hepatic MCP-1 and hydroxyproline; these results were confirmed by the histopathological investigation. In contrast, nano-encapsulated and nano-emulsion carvacrol were able to ameliorate these negative changes in the thioacetamide injected rats. However, the effect of the nano-encapsulated form of carvacrol was more prominent than the nano-emulsion form. Nano-encapsulated and nano-emulsion carvacrol can ameliorate thioacetamide induced liver injury. These results could be attributed to the potential anti-inflammatory, antioxidant, and anti-apoptotic activities of carvacrol in addition to the effectiveness of the encapsulation technique that can protect

Polyaniline coated cellulose fiber / polyvinyl alcohol composites with high dielectric permittivity and low percolation threshold

NASA Astrophysics Data System (ADS)

Anju, V. P.; Narayanankutty, Sunil K.

2016-01-01

Cost effective, high performance dielectric composites based on polyvinyl alcohol, cellulose fibers and polyaniline were prepared and the dielectric properties were studied as a function of fiber content, fiber dimensions and polyaniline content over a frequency range of 40 Hz to 30 MHz. The short cellulose fibers were size-reduced to micro and nano levels prior to coating with polyaniline. Fiber surface was coated with Polyaniline (PANI) by an in situ polymerization technique in aqueous medium. The composites were then prepared by solution casting method. Short cellulose fiber composites showed a dielectric constant (DEC) of 2.3 x 105 at 40 Hz. For the micro- and nano- cellulose fiber composites the DEC was increased to 4.5 x 105 and 1.3 x 108, respectively. To gain insight into the inflection point of the dielectric data polynomial regression analysis was carried out. The loss tangent of all the composites remained at less than 1.5. Further, AC conductivity, real and imaginary electric moduli of all the composites were evaluated. PVA nanocomposite attained an AC conductivity of 3 S/m. These showed that by controlling the size of the fiber used, it was possible to tune the permittivity and dielectric loss to desired values over a wide range. These novel nanocomposites, combining high dielectric constant and low dielectric loss, can be effectively used in applications such as high-charge storage capacitors.

Cylindrical micelles of a POSS amphiphilic dendrimer as nano-reactors for polymerization.

PubMed

Weng, Jing-Ting; Yeh, Tso-Fan; Samuel, Ashok Zachariah; Huang, Yi-Fan; Sie, Jyun-Hao; Wu, Kuan-Yi; Peng, Chi-How; Hamaguchi, Hiro-O; Wang, Chien-Lung

2018-02-15

A low generation amphiphilic dendrimer, POSS-AD, which has a POSS core and eight amphiphilic arms, was synthesized and used as a nano-reactor to produce well-defined polymer nano-cylinders. Confirmed by small-angle X-ray scattering (SAXS), Raman and NMR spectrometry, monodispersed cylindrical micelles that contain a hydrophilic cavity with a diameter of 2.09 nm and a length of 4.26 nm were produced via co-assembling POSS-AD with hydrophilic liquids, such as H 2 O and HEMA in hydrophobic solvents. Taking the HEMA/POSS-AD cylindrical micelles as nano-reactors, polymerization of HEMA within the micelles results in polymer nano-cylinders (POSS-ADNPs) with a diameter of 2.24 nm and a length of 5.02 nm. The study confirmed that despite the inability to maintain specific shape in solution, low generation dendrimers form well-defined nano-containers or nano-reactors, which relies on co-assembling with hydrophilic guest molecules. These nano-reactors are robust enough to maintain their shape during the polymerization of the guest molecules. Polymer nano-cylinders with dimensions less than 10 nm can thus be produced from the HEMA/POSS-AD micelles. Since the chemical structure of low-generation dendrimers and the contents of the co-assembled nano-reactors can be easily adjusted, the concept holds the potential for the further developments of low-generation amphiphilic dendrimers.

Synthesis and Characterization of Nano Boron Nitride Reinforced Magnesium Composites Produced by the Microwave Sintering Method

PubMed Central

Seetharaman, Sankaranarayanan; Subramanian, Jayalakshmi; Tun, Khin Sandar; Hamouda, Abdelmagid S.; Gupta, Manoj

2013-01-01

In this study, magnesium composites with nano-size boron nitride (BN) particulates of varying contents were synthesized using the powder metallurgy (PM) technique incorporating microwave-assisted two-directional sintering followed by hot extrusion. The effect of nano-BN addition on the microstructural and the mechanical behavior of the developed Mg/BN composites were studied in comparison with pure Mg using the structure-property correlation. Microstructural characterization revealed uniform distribution of nano-BN particulates and marginal grain refinement. The coefficient of thermal expansion (CTE) value of the magnesium matrix was improved with the addition of nano-sized BN particulates. The results of XRD studies indicate basal texture weakening with an increase in nano-BN addition. The composites showed improved mechanical properties measured under micro-indentation, tension and compression loading. While the tensile yield strength improvement was marginal, a significant increase in compressive yield strength was observed. This resulted in the reduction of tension-compression yield asymmetry and can be attributed to the weakening of the strong basal texture. PMID:28809252

Hybrid mode-locked fiber ring laser using graphene and charcoal nanoparticles as saturable absorbers

NASA Astrophysics Data System (ADS)

Hu, Hongyu; Zhang, Xiang; Li, Wenbo; Dutta, Niloy K.

2016-05-01

A fiber ring laser which implements hybrid mode locking technique has been proposed and experimentally demonstrated to generate pulse train at 20 GHz repetition rate with ultrashort pulse width. Graphene and charcoal nano-particles acting as passive mode lockers are inserted into a rational harmonic mode-locked fiber laser to improve the performance. With graphene saturable absorbers, the pulse duration is shortened from 5.3 ps to 2.8 ps, and with charcoal nano-particles, it is shortened to 3.2 ps. The RF spectra show that supermode noise can be removed in the presence of the saturable absorbers. Numerical simulation of the pulse transmission has also been carried out, which shows good agreement with the experimental results.

Omnidirectional fiber optic tiltmeter

DOEpatents

Benjamin, B.C.; Miller, H.M.

1983-06-30

A tiltmeter is provided which is useful in detecting very small movements such as earth tides. The device comprises a single optical fiber, and an associated weight affixed thereto, suspended from a support to form a pendulum. A light source, e.g., a light emitting diode, mounted on the support transmits light through the optical fiber to a group of further optical fibers located adjacent to but spaced from the free end of the single optical fiber so that displacement of the single optical fiber with respect to the group will result in a change in the amount of light received by the individual optical fibers of the group. Photodetectors individually connectd to the fibers produce corresponding electrical outputs which are differentially compared and processed to produce a resultant continuous analog output representative of the amount and direction of displacement of the single optical fiber.

Nano-technology and nano-toxicology.

PubMed

Maynard, Robert L

2012-01-01

Rapid developments in nano-technology are likely to confer significant benefits on mankind. But, as with perhaps all new technologies, these benefits are likely to be accompanied by risks, perhaps by new risks. Nano-toxicology is developing in parallel with nano-technology and seeks to define the hazards and risks associated with nano-materials: only when risks have been identified they can be controlled. This article discusses the reasons for concern about the potential effects on health of exposure to nano-materials and relates these to the evidence of the effects on health of the ambient aerosol. A number of hypotheses are proposed and the dangers of adopting unsubstantiated hypotheses are stressed. Nano-toxicology presents many challenges and will need substantial financial support if it is to develop at a rate sufficient to cope with developments in nano-technology.

Nano-technology and nano-toxicology

PubMed Central

Maynard, Robert L.

2012-01-01

Rapid developments in nano-technology are likely to confer significant benefits on mankind. But, as with perhaps all new technologies, these benefits are likely to be accompanied by risks, perhaps by new risks. Nano-toxicology is developing in parallel with nano-technology and seeks to define the hazards and risks associated with nano-materials: only when risks have been identified they can be controlled. This article discusses the reasons for concern about the potential effects on health of exposure to nano-materials and relates these to the evidence of the effects on health of the ambient aerosol. A number of hypotheses are proposed and the dangers of adopting unsubstantiated hypotheses are stressed. Nano-toxicology presents many challenges and will need substantial financial support if it is to develop at a rate sufficient to cope with developments in nano-technology. PMID:22662021

Production and Application of Olivine Nano-Silica in Concrete

NASA Astrophysics Data System (ADS)

Mardiana, Oesman; Haryadi

2017-05-01

The aim of this research was to produce nano silica by synthesis of nano silica through extraction and dissolution of ground olivine rock, and applied the nano silica in the design concrete mix. The producing process of amorphous silica used sulfuric acid as the dissolution reagent. The separation of ground olivine rock occurred when the rock was heated in a batch reactor containing sulfuric acid. The results showed that the optimum mole ratio of olivine- acid was 1: 8 wherein the weight ratio of the highest nano silica generated. The heating temperature and acid concentration influenced the mass of silica produced, that was at temperature of 90 °C and 3 M acid giving the highest yield of 44.90%. Characterization using Fourier Transform Infrared (FTIR ) concluded that amorphous silica at a wavenumber of 1089 cm-1 indicated the presence of siloxane, Si-O-Si, stretching bond. Characterization using Scanning Electron Microscope - Energy Dispersive Spectroscopy (SEM-EDS) showed the surface and the size of the silica particles. The average size of silica particles was between 1-10 μm due to the rapid aggregation of the growing particles of nano silica into microparticles, caused of the pH control was not fully achieved.

Understanding longitudinal wood fiber ultra-structure for producing cellulose nanofibrils using disk milling with diluted acid prehydrolysis

Treesearch

Yanlin Qin; Xueqing Qiu; Junyong Zhu

2016-01-01

Here we used dilute oxalic acid to pretreat a kraft bleached Eucalyptus pulp (BEP) fibers to facilitate mechanical fibrillation in producing cellulose nanofibrils using disk milling with substantial mechanical energy savings. We successfully applied a reaction kinetics based combined hydrolysis factor (CHFx) as a severity factor to quantitatively...

Multi-material optoelectronic fiber devices

NASA Astrophysics Data System (ADS)

Sorin, F.; Yan, Wei; Volpi, Marco; Page, Alexis G.; Nguyen Dang, Tung; Qu, Y.

2017-05-01

The recent ability to integrate materials with different optical and optoelectronic properties in prescribed architectures within flexible fibers is enabling novel opportunities for advanced optical probes, functional surfaces and smart textiles. In particular, the thermal drawing process has known a series of breakthroughs in recent years that have expanded the range of materials and architectures that can be engineered within uniform fibers. Of particular interest in this presentation will be optoelectronic fibers that integrate semiconductors electrically addressed by conducting materials. These long, thin and flexible fibers can intercept optical radiation, localize and inform on a beam direction, detect its wavelength and even harness its energy. They hence constitute ideal candidates for applications such as remote and distributed sensing, large-area optical-detection arrays, energy harvesting and storage, innovative health care solutions, and functional fabrics. To improve performance and device complexity, tremendous progresses have been made in terms of the integrated semiconductor architectures, evolving from large fiber solid-core, to sub-hundred nanometer thin-films, nano-filaments and even nanospheres. To bridge the gap between the optoelectronic fiber concept and practical applications however, we still need to improve device performance and integration. In this presentation we will describe the materials and processing approaches to realize optoelectronic fibers, as well as give a few examples of demonstrated systems for imaging as well as light and chemical sensing. We will then discuss paths towards practical applications focusing on two main points: fiber connectivity, and improving the semiconductor microstructure by developing scalable approaches to make fiber-integrated single-crystal nanowire based devices.

Fabrication of Microfibrous and Nano-/Microfibrous Scaffolds: Melt and Hybrid Electrospinning and Surface Modification of Poly(L-lactic acid) with Plasticizer

PubMed Central

Yoon, Young Il; Park, Ko Eun; Lee, Seung Jin; Park, Won Ho

2013-01-01

Biodegradable poly(L-lactic acid) (PLA) fibrous scaffolds were prepared by electrospinning from a PLA melt containing poly(ethylene glycol) (PEG) as a plasticizer to obtain thinner fibers. The effects of PEG on the melt electrospinning of PLA were examined in terms of the melt viscosity and fiber diameter. Among the parameters, the content of PEG had a more significant effect on the average fiber diameter and its distribution than those of the spinning temperature. Furthermore, nano-/microfibrous silk fibroin (SF)/PLA and PLA/PLA composite scaffolds were fabricated by hybrid electrospinning, which involved a combination of solution electrospinning and melt electrospinning. The SF/PLA (20/80) scaffolds consisted of a randomly oriented structure of PLA microfibers (average fiber diameter = 8.9 µm) and SF nanofibers (average fiber diameter = 820 nm). The PLA nano-/microfiber (20/80) scaffolds were found to have similar pore parameters to the PLA microfiber scaffolds. The PLA scaffolds were treated with plasma in the presence of either oxygen or ammonia gas to modify the surface of the fibers. This approach of controlling the surface properties and diameter of fibers could be useful in the design and tailoring of novel scaffolds for tissue engineering. PMID:24381937

SWS grating for UV band filter by nano-imprint

NASA Astrophysics Data System (ADS)

Lin, Jian-Shian; Liao, Ke-Hao; Chen, Chang-Tai; Lai, Chieh-Lung; Ko, Cheng-Hao

2009-05-01

Regarding to researches on manufacturing process, the fabrication of nano structures on SWS (subwavelength structured) grating are mainly produced by photo lithography. We find that UV light transmission efficiency of PET film significantly drops 50% when we put nano structures on the surface of material. In this paper, we add nano structures on the surface of PET film and create a UV band filter. Decent optical filtering effects can be achieved by combining the characteristics of PET materials with nano structures on their surfaces.

Fluorescent fiber diagnostics

DOEpatents

Toeppen, John S.

1994-10-04

A fluorescent fiber (13) having a doped core (16) is pumped (11) by light (18) of a relatively short wavelength to produce fluorescence at a longer wavelength that is detected by detector (24). The level of fluorescence is monitored (26) and evaluated to provide information as to the excitation of the fiber (13) or the environment thereof. In particular, the level of intensity of the detected fluorescence may be used to measure the intensity of a light beam (18) passing axially through an optical fiber system (12) (FIG. 1 ), or the intensity of a light beam (46) passing radially through a fluorescent fiber (13) (FIG. 2 ), or the level of a fluid (32) in a tank (31) (FIG. 3 ), or a scintillation event (37) in a fluorescent fiber (13) pumped to produce amplification of the scintillation event (FIG. 4 ).

Fluorescent fiber diagnostics

DOEpatents

Toeppen, John S.

1994-01-01

A fluorescent fiber (13) having a doped core (16) is pumped (11) by light (18) of a relatively short wavelength to produce fluorescence at a longer wavelength that is detected by detector (24). The level of fluorescence is monitored (26) and evaluated to provide information as to the excitation of the fiber (13) or the environment thereof. In particular, the level of intensity of the detected fluorescence may be used to measure the intensity of a light beam (18) passing axially through an optical fiber system (12) (FIG. 1 ), or the intensity of a light beam (46) passing radially through a fluorescent fiber (13) (FIG. 2 ), or the level of a fluid (32) in a tank (31) (FIG. 3 ), or a scintillation event (37) in a fluorescent fiber (13) pumped to produce amplification of the scintillation event (FIG. 4 ).

FIBER LASER CONSTRUCTION AND THEORY INCLUDING FIBER BRAGG GRATINGS Photonic Crystal Fibers (PCFs) and applications of gas filled PCFs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sutton, Jacob O.

The principles used in fiber lasers have been around for a while but it is only within the past few years that fiber lasers have become commercially available and used in high power laser applications. This paper will focus on the basic design principles of fiber lasers, including fiber Bragg gratings, principles of operation, and forms of non-linear effects. It will describe the type and associated doping of the fiber used and difficult designs used to guide energy from the pump to the active medium. Topics covered include fiber laser design, fiber Bragg gratings, materials used, differences in quantum energymore » loss, thermo-optical effects, stimulated Raman scattering, Brillouin scattering, photonic crystal fibers and applications of gas filled Photonic Crystal Fibers (PCFs). Thanks to fiber lasers, the energy required to produce high power lasers has greatly dropped and as such we can now produce kW power using a standard 120V 15A circuit. High power laser applications are always requiring more power. The fiber laser can now deliver the greater power that these applications demand. Future applications requiring more power than can be combined using standard materials or configurations will need to be developed to overcome the high energy density and high non-linear optical scattering effects present during high power operations.« less

Integrated Surface and Mechanical Characterization of Freestanding Biological and Other Nano-Structures Using Atomic Force Microscopy

NASA Astrophysics Data System (ADS)

Wang, Xin

This dissertation is focused on surface and mechanical characterization of freestanding biological and other nano-structures using atomic force microscopy including two parts: cell mechanics and nano-structure mechanics. The main purpose of this work is to investigate how the nano- / micro-scale mechanical properties affect macro-scale function. In cancer cells, efficacy of drug delivery is oftentimes declined due to the thick dendritic network of oligosaccharide mucin chains on the cell surface. AFM is used to measure the force needed to pierce the mucin layer to reach the cell surface. A pool of ovarian, pancreatic, lung, colorectal and breast cancer cells are characterized. The studies offer additional support for the development of clinical and pharmaceutical approaches to combat mucin over-expression in tumors during cancer chemotherapy. Macroscopic adhesion-aggregation and subsequent transportation of microorganisms in porous medium are closely related to the microscopic deformation and adhesion mechanical properties. The classical Tabor's parameter is modified. Multiple bacterial strains are characterized in terms of aggregates size, aggregation index and transportation kinetics. AFM is employed to obtain the microscopic coupled adhesion-deformation properties. The strong correlation between Tabor's parameter and aggregation-deposition-transportation suggests the AFM characterization is capable of making reliable predication of macroscopic behavior. A novel "nano-cheese-cutter" is fabricated on tipless AFM cantilever to measure elastic modulus and interfacial adhesion of a 1-D freestanding nano-structure. A single electrospun fiber is attached to the free end of AFM cantilever, while another fiber is similarly prepared on a mica substrate in an orthogonal direction. An external load is applied to deform the two fibers into complementary V-shapes. This work is extended to investigate the interfacial adhesion energy between dissimilar materials. SWCNT thin

PET fiber fabrics modified with bioactive titanium oxide for bone substitutes.

PubMed

Kokubo, Tadashi; Ueda, Takahiro; Kawashita, Masakazu; Ikuhara, Yuichi; Takaoka, Gikan H; Nakamura, Takashi

2008-02-01

A rectangular specimen of polyethylene terephthalate (PET) was soaked in a titania solution composed of titanium isopropoxide, water, ethanol and nitric acid at 25 degrees C for 1 h. An amorphous titanium oxide was formed uniformly on the surface of PET specimen, but did not form an apatite on its surface in a simulated body fluid (SBF) within 3 d. The PET plate formed with the amorphous titanium oxide was subsequently soaked in water or HCl solutions with different concentrations at 80 degrees C for different periods of time. The titanium oxide on PET was transformed into nano-sized anatase by the water treatment and into nano-sized brookite by 0.10 M HCl treatment at 80 degrees C for 8 d. The former did not form the apatite on its surface in SBF within 3 d, whereas the latter formed the apatite uniformly on its surface. Adhesive strength of the titanium oxide and apatite layers to PET plate was increased by pre-treatment of PET with 2 wt% NaOH solution at 40 degrees C for 2 h. A two-dimensional fabric of PET fibers 24 microm in diameter was subjected to the NaOH pre-treatment at 40 degrees C, titania solution treatment at 25 degrees C and subsequent 0.10 M HCl treatment at 80 degrees C. Thus treated PET fabric formed the apatite uniformly on surfaces of individual fibers constituting the fabric in SBF within 3 d. Two or three dimensional PET fabrics modified with the nano-sized brookite on surfaces of the individual fibers constituting the fabric by the present method are believed to be useful as flexible bone substitutes, since they could be integrated with living bone through the apatite formed on their constituent fibers.

Laser-treated electrospun fibers loaded with nano-hydroxyapatite for bone tissue engineering.

PubMed

Aragon, Javier; Navascues, Nuria; Mendoza, Gracia; Irusta, Silvia

2017-06-15

Core-shell polycaprolactone/polycaprolactone (PCL/PCL) and polycaprolactone/polyvinyl acetate (PCL/PVAc) electrospun fibers loaded with synthesized nanohydroxyapatite (HAn) were lased treated to create microporosity. The prepared materials were characterized by XRD, FTIR, TEM and SEM. Uniform and randomly oriented beadless fibrous structures were obtained in all cases. Fibers diameters were in the 150-300nm range. Needle-like HAn nanoparticles with mean diameters of 20nm and length of approximately 150nm were mostly encase inside the fibers. Laser treated materials present micropores with diameters in the range 70-120μm for PCL-HAn/PCL fibers and in the 50-90μm range for PCL-HAn/PVAC material. Only samples containing HAn presented bioactivity after incubation during 30days in simulated body fluid. All scaffolds presented high viability, very low mortality, and human osteoblast proliferation. Biocompatibility was increased by laser treatment due to the surface and porosity modification. Copyright © 2017 Elsevier B.V. All rights reserved.

Fabrication of a multi-walled carbon nanotube-deposited glass fiber air filter for the enhancement of nano and submicron aerosol particle filtration and additional antibacterial efficacy.

PubMed

Park, Jae Hong; Yoon, Ki Young; Na, Hyungjoo; Kim, Yang Seon; Hwang, Jungho; Kim, Jongbaeg; Yoon, Young Hun

2011-09-01

We grew multi-walled carbon nanotubes (MWCNTs) on a glass fiber air filter using thermal chemical vapor deposition (CVD) after the filter was catalytically activated with a spark discharge. After the CNT deposition, filtration and antibacterial tests were performed with the filters. Potassium chloride (KCl) particles (<1 μm) were used as the test aerosol particles, and their number concentration was measured using a scanning mobility particle sizer. Antibacterial tests were performed using the colony counting method, and Escherichia coli (E. coli) was used as the test bacteria. The results showed that the CNT deposition increased the filtration efficiency of nano and submicron-sized particles, but did not increase the pressure drop across the filter. When a pristine glass fiber filter that had no CNTs was used, the particle filtration efficiencies at particle sizes under 30 nm and near 500 nm were 48.5% and 46.8%, respectively. However, the efficiencies increased to 64.3% and 60.2%, respectively, when the CNT-deposited filter was used. The reduction in the number of viable cells was determined by counting the colony forming units (CFU) of each test filter after contact with the cells. The pristine glass fiber filter was used as a control, and 83.7% of the E. coli were inactivated on the CNT-deposited filter. Copyright © 2011 Elsevier B.V. All rights reserved.

A comparison study of nanofiber, microfiber, and new composite nano/microfiber polymers used as sorbents for on-line solid phase extraction in chromatography system.

PubMed

Háková, Martina; Havlíková, Lucie Chocholoušová; Chvojka, Jiří; Erben, Jakub; Solich, Petr; Švec, František; Šatínský, Dalibor

2018-09-06

Three different approaches has been used to obtain nano/micro fibers and their diversity and extraction properties were examined. The effect of their structure on stability in an ultra-high-performance liquid chromatography (UHPLC) system during on-line SPE procedure was monitored. Five types of various nano/micro fiber polymers were used as sorbents: polyamide 6 nanofibers, polyvinylidene difluoride nanofibers, polyethylene microfibers, and two new polycaprolactone microfiber/nanofiber and polycaprolactone microfibers/polyvinylidene difluoride nanofibers composite polymers. The fiber polymers were filled in a cartridge directly connected to the UHPLC system and tested. For each polymer, the optimal conditions of the on-line extraction were found and potential applicability on real samples was tested. The determination of ochratoxin A (OTA) in beer matrix was chosen as a case study. Relevant factors such as the mechanical and chemical stability of the nano/microfibers, filling the cartridges, fiber reusability and the possibility and the repeatability of all processes were involved in the proposed study. A new nano/micro composite sorbent consisting of polycaprolactone microfibers/polyvinylidene difluoride nanofibers was chosen as the most suitable sorbent for the on-line extraction of OTA from a beer matrix. The tested validation parameters had the value of intra-day precision lower than 1.48%, linearity in the range from 0.5 to 100 μg L -1 with r 2  ≥ 0.9999 for standard and matrix calibration curve, and recovery in the range 99.1-103.9% at five concentration levels. Long-term precision evaluated for 31 analyses over the period of three months did not exceed 2.9% RSD. It confirmed the column reusability and perfect stability of nano/micro composite sorbent in the presence of organic solvents and after repeated injection of a complex beer matrix. Copyright © 2018 Elsevier B.V. All rights reserved.

Developments in Nano-Satellite Structural Subsystem Design at NASA-GSFC

NASA Technical Reports Server (NTRS)

Rossoni, Peter; Panetta, Peter V.

1999-01-01

The NASA-GSFC Nano-satellite Technology Development Program will enable flying constellations of tens to hundreds of nano-satellites for future NASA Space and Earth Science missions. Advanced technology components must be developed to make these future spacecraft compact, lightweight, low-power, low-cost, and survivable to a radiation environment over a two-year mission lifetime. This paper describes the efforts underway to develop lightweight, low cost, and multi-functional structures, serviceable designs, and robust mechanisms. As designs shrink, the integration of various subsystems becomes a vital necessity. This paper also addresses structurally integrated electrical power, attitude control, and thermal systems. These innovations bring associated fabrication, integration, and test challenges. Candidate structural materials and processes are examined and the merits of each are discussed. Design and fabrication processes include flat stock composite construction, cast aluminum-beryllium alloy, and an injection molded fiber-reinforced plastic. A viable constellation deployment scenario is described as well as a Phase-A Nano-satellite Pathfinder study.

Programming Cells for Dynamic Assembly of Inorganic Nano-Objects with Spatiotemporal Control.

PubMed

Wang, Xinyu; Pu, Jiahua; An, Bolin; Li, Yingfeng; Shang, Yuequn; Ning, Zhijun; Liu, Yi; Ba, Fang; Zhang, Jiaming; Zhong, Chao

2018-04-01

Programming living cells to organize inorganic nano-objects (NOs) in a spatiotemporally precise fashion would advance new techniques for creating ordered ensembles of NOs and new bio-abiotic hybrid materials with emerging functionalities. Bacterial cells often grow in cellular communities called biofilms. Here, a strategy is reported for programming dynamic biofilm formation for the synchronized assembly of discrete NOs or hetero-nanostructures on diverse interfaces in a dynamic, scalable, and hierarchical fashion. By engineering Escherichia coli to sense blue light and respond by producing biofilm curli fibers, biofilm formation is spatially controlled and the patterned NOs' assembly is simultaneously achieved. Diverse and complex fluorescent quantum dot patterns with a minimum patterning resolution of 100 µm are demonstrated. By temporally controlling the sequential addition of NOs into the culture, multilayered heterostructured thin films are fabricated through autonomous layer-by-layer assembly. It is demonstrated that biologically dynamic self-assembly can be used to advance a new repertoire of nanotechnologies and materials with increasing complexity that would be otherwise challenging to produce. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Recent development of antifouling polymers: structure, evaluation, and biomedical applications in nano/micro-structures.

PubMed

Liu, Lingyun; Li, Wenchen; Liu, Qingsheng

2014-01-01

Antifouling polymers have been proven to be vital to many biomedical applications such as medical implants, drug delivery, and biosensing. This review covers the major development of antifouling polymers in the last 2 decades, including the material chemistry, structural factors important to antifouling properties, and how to challenge or evaluate the antifouling performances. We then discuss the applications of antifouling polymers in nano/micro-biomedical applications in the form of nanoparticles, thin coatings for medical devices (e.g., artificial joint, catheter, wound dressing), and nano/microscale fibers. © 2014 Wiley Periodicals, Inc.

Differential effect of hydroxyapatite nano-particle versus nano-rod decorated titanium micro-surface on osseointegration.

PubMed

Bai, Long; Liu, Yanlian; Du, Zhibin; Weng, Zeming; Yao, Wei; Zhang, Xiangyu; Huang, Xiaobo; Yao, Xiaohong; Crawford, Ross; Hang, Ruiqiang; Huang, Di; Tang, Bin; Xiao, Yin

2018-06-15

Coating materials applied for intraosseous implants must be optimized to stimulate osseointegration. Osseointegration is a temporal and spatial physiological process that not only requires interactions between osteogenesis and angiogenesis but also necessitates a favorable immune microenvironment. It is now well-documented that hierarchical nano-micro surface structures promote the long-term stability of implants, the interactions between nano-micro structure and the immune response are largely unknown. Here, we report the effects of microporous titanium (Ti) surfaces coated with nano-hydroxyapatite (HA) produced by micro-arc oxidation and steam-hydrothermal treatment (SHT) on multiple cell behavior and osseointegration. By altering the processing time of SHT it was possible to shift HA structures from nano-particles to nano-rods on the microporous Ti surfaces. Ti surfaces coated with HA nano-particles were found to modulate the inflammatory response resulting in an osteoimmune microenvironment more favorable for osteo-/angio-genesis, most likely via the activation of certain key signaling pathways (TGF-β, OPG/RANKL, and VEGF). By contrast, Ti surfaces coated with nano-rod shaped HA particles had a negative impact on osteo-/angio-genesis and osteoimmunomodulation. In vivo results further demonstrated that Ti implant surfaces decorated with HA nano-particles can stimulate new bone formation and osseointegration with enhanced interaction between osteocytes and implant surfaces. This study demonstrated that Ti implants with micro-surfaces coated with nano-particle shaped HA have a positive impact on osseointegration. Osteo-/angio-genesis are of importance during osteointegration of the implants. Recent advances unravel that immune response of macrophages and its manipulated osteoimmunomodulation also exerts a pivotal role to determine the fate of the implant. Surface nano-micro modification has evidenced to be efficient to influence osteogenesis, however, little is

Nano-stepper-driven optical shutter for applications in free-space micro-optics

NASA Astrophysics Data System (ADS)

Zawadzka, Justyna; Li, Lijie; Unamuno, Anartz; Uttamchandani, Deepak G.

2002-09-01

In this paper we report a simple design of a micro-optical shutter/attenuator. The standard MUMPS process was used to fabricate the device. A vertically erected, gold-coated, 200x300 mm side length micro-mirror was precisely placed between the end faces of two closely spaced optical fibers. The position of the micro-mirror with respect to the optical fiber end face was controlled by a nano-stepping motor array. Optical and mechanical tests were performed on the device. A 1.55 mm laser beam was sent along the optical fiber. When the micro-mirror was removed from the front of the fiber, the coupling efficiency between two fibers was -10 dBm. Once the micro-mirror was placed in the optical path the coupling efficiency dropped to -51.5 dBm. The best attenuation was obtained when the micro-mirror blocked the whole cross-section of the laser beam diameter. It is evident that the device can operate as a high precision fiber optic attenuator or shutter.

Formation and characterization of mullite fibers produced by inviscid melt-spinning

NASA Astrophysics Data System (ADS)

Xiao, Zhijun

IMS is a technique used to form fibers from low viscosity melts by means of stream stabilization in a reactant gas, in this case propane. Mullite (3Alsb2Osb3*2SiOsb2) was selected as the material to be fiberized. A stable mullite melt was obtained at 2000sp°C. Some short fibers and shot were formed in the fiber forming experiments. Crucible material selection is a prerequisite for proper application of the IMS technique. The effect of two crucible materials-graphite and boron nitride were studied. A carbothermal reaction occurred between the mullite melt and the graphite crucible. Boron nitride was selected as the crucible material because a relatively stable melt could be obtained. Operating environment is another factor that affects IMS mullite fiber formation. The effects of vacuum, nitrogen and argon on mullite melting behavior were studied. Argon gas was selected as the operating environment. A 2sp3 factorial design was developed to study the effect of such variables as temperature, holding time at the temperature, and heating rate on mullite melting behavior. The effects of the variables and interactions were calculated. Temperature has the biggest positive effect, holding time is the second, heating rate just has a very small negative effect. A detailed investigation of the mullite decomposition mechanism and kinetics was conducted in this work. A solid reaction mechanism was proposed. The kinetic results and IR analysis support the proposed mechanism. The carbon source inside the furnace led to the decomposition of mullite. A feasible experimental technique was developed to prevent the decomposition of mullite. The experiments with this design completely controlled the mullite decomposition. The short fibers, shot and some side products formed in the fiber forming experiments were characterized using XRD, XRF and SEM-EDS. The composition of the short fiber and shot was in the range of mullite composition. XRD showed that the diffraction pattern of shot is

Fiber distributed feedback laser

NASA Technical Reports Server (NTRS)

Elachi, C.; Evans, G. A.; Yeh, C. (Inventor)

1976-01-01

Utilizing round optical fibers as communication channels in optical communication networks presents the problem of obtaining a high efficiency coupling between the optical fiber and the laser. A laser is made an integral part of the optical fiber channel by either diffusing active material into the optical fiber or surrounding the optical fiber with the active material. Oscillation within the active medium to produce lasing action is established by grating the optical fiber so that distributed feedback occurs.

Evaluation of Fiber Bragg Grating and Distributed Optical Fiber Temperature Sensors

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCary, Kelly Marie

Fiber optic temperature sensors were evaluated in the High Temperature Test Lab (HTTL) to determine the accuracy of the measurements at various temperatures. A distributed temperature sensor was evaluated up to 550C and a fiber Bragg grating sensor was evaluated up to 750C. HTTL measurements indicate that there is a drift in fiber Bragg sensor over time of approximately -10C with higher accuracy at temperatures above 300C. The distributed sensor produced some bad data points at and above 500C but produced measurements with less than 2% error at increasing temperatures up to 400C

Optical fibers and Fluorosensors having improved power efficiency and methods of producing same

NASA Technical Reports Server (NTRS)

Egalon, Claudio O. (Inventor); Rogowski, Robert S. (Inventor)

1993-01-01

Optical fibers may have applications including fluorosensors which sense the concentration of an analyte. Like communication fibers, these fluorosensors are modeled using a weakly guiding approximation which is only effective when the difference between the respective refractive indices of the fiber core and surrounding cladding are minimal. An optical fiber fluorosensor is provided having a portion of a fiber core which is surrounded by an active cladding which is permeable by the analyte to be sensed and containing substances which emit light waves upon excitation. A remaining portion of the fiber core is surrounded by a guide cladding which guides these light waves to a sensor which detects the intensity of waves, which is a function of the analyte concentration. Contrary to conventional weakly guiding principles, the difference between the respective indices of refraction of the fiber core is surrounded by an active cladding which is thin enough such that its index of refraction is effectively that of the surrounding atmosphere, thereby the atmosphere guides the injective indices of the fiber core and the cladding results in an unexpected increase in the power efficiency of the fiber core.

Thermal oxidation induced degradation of carbon fiber reinforced composites and carbon nanotube sheet enhanced fiber/matrix interface for high temperature aerospace structural applications

NASA Astrophysics Data System (ADS)

Haque, Mohammad Hamidul

Recent increase in the use of carbon fiber reinforced polymer matrix composite, especially for high temperature applications in aerospace primary and secondary structures along with wind energy and automotive industries, have generated new challenges to predict its failure mechanisms and service life. This dissertation reports the experimental study of a unidirectional carbon fiber reinforced bismaleimide (BMI) composites (CFRC), an excellent candidate for high temperature aerospace components, undergoing thermal oxidation at 260 °C in air for over 3000 hours. The key focus of the work is to investigate the mechanical properties of the carbon fiber BMI composite subjected to thermal aging in three key aspects - first, studying its bulk flexural properties (in macro scale), second, characterizing the crack propagation along the fiber direction, representing the interfacial bonding strength between fiber and matrix (in micro scale), and third, introducing nano-structured materials to modify the interface (in nano scale) between the carbon fiber and BMI resin and mechanical characterization to study its influence on mitigating the aging effect. Under the first category, weight loss and flexural properties have been monitored as the oxidation propagates through the fiber/matrix interface. Dynamic mechanical analysis and micro-computed tomography analysis have been performed to analyze the aging effects. In the second category, the long-term effects of thermal oxidation on the delamination (between the composite plies) and debonding (between fiber and matrix) type fracture toughness have been characterized by preparing two distinct types of double cantilever beam specimens. Digital image correlation has been used to determine the deformation field and strain distribution around the crack propagation path. Finally the resin system and the fiber/matrix interface have been modified using nanomaterials to mitigate the degradations caused by oxidation. Nanoclay modified

Advanced Fiber-optic Monitoring System for Space-flight Applications

NASA Technical Reports Server (NTRS)

Hull, M. S.; VanTassell, R. L.; Pennington, C. D.; Roman, M.

2005-01-01

Researchers at Luna Innovations Inc. and the National Aeronautic and Space Administration s Marshall Space Flight Center (NASA MSFC) have developed an integrated fiber-optic sensor system for real-time monitoring of chemical contaminants and whole-cell bacterial pathogens in water. The system integrates interferometric and evanescent-wave optical fiber-based sensing methodologies with atomic force microscopy (AFM) and long-period grating (LPG) technology to provide versatile measurement capability for both micro- and nano-scale analytes. Sensors can be multiplexed in an array format and embedded in a totally self-contained laboratory card for use with an automated microfluidics platform.

Campanile Near-Field Probes Fabricated by Nanoimprint Lithography on the Facet of an Optical Fiber

DOE PAGES

Calafiore, Giuseppe; Koshelev, Alexander; Darlington, Thomas P.; ...

2017-05-10

One of the major challenges to the widespread adoption of plasmonic and nano-optical devices in real-life applications is the difficulty to mass-fabricate nano-optical antennas in parallel and reproducible fashion, and the capability to precisely place nanoantennas into devices with nanometer-scale precision. In this study, we present a solution to this challenge using the state-of-the-art ultraviolet nanoimprint lithography (UV-NIL) to fabricate functional optical transformers onto the core of an optical fiber in a single step, mimicking the 'campanile' near-field probes. Imprinted probes were fabricated using a custom-built imprinter tool with co-axial alignment capability with sub < 100 nm position accuracy, followedmore » by a metallization step. Scanning electron micrographs confirm high imprint fidelity and precision with a thin residual layer to facilitate efficient optical coupling between the fiber and the imprinted optical transformer. The imprinted optical transformer probe was used in an actual NSOM measurement performing hyperspectral photoluminescence mapping of standard fluorescent beads. The calibration scans confirmed that imprinted probes enable sub-diffraction limited imaging with a spatial resolution consistent with the gap size. This novel nano-fabrication approach promises a low-cost, high-throughput, and reproducible manufacturing of advanced nano-optical devices.« less

Campanile Near-Field Probes Fabricated by Nanoimprint Lithography on the Facet of an Optical Fiber

DOE Office of Scientific and Technical Information (OSTI.GOV)

Calafiore, Giuseppe; Koshelev, Alexander; Darlington, Thomas P.

One of the major challenges to the widespread adoption of plasmonic and nano-optical devices in real-life applications is the difficulty to mass-fabricate nano-optical antennas in parallel and reproducible fashion, and the capability to precisely place nanoantennas into devices with nanometer-scale precision. In this study, we present a solution to this challenge using the state-of-the-art ultraviolet nanoimprint lithography (UV-NIL) to fabricate functional optical transformers onto the core of an optical fiber in a single step, mimicking the 'campanile' near-field probes. Imprinted probes were fabricated using a custom-built imprinter tool with co-axial alignment capability with sub < 100 nm position accuracy, followedmore » by a metallization step. Scanning electron micrographs confirm high imprint fidelity and precision with a thin residual layer to facilitate efficient optical coupling between the fiber and the imprinted optical transformer. The imprinted optical transformer probe was used in an actual NSOM measurement performing hyperspectral photoluminescence mapping of standard fluorescent beads. The calibration scans confirmed that imprinted probes enable sub-diffraction limited imaging with a spatial resolution consistent with the gap size. This novel nano-fabrication approach promises a low-cost, high-throughput, and reproducible manufacturing of advanced nano-optical devices.« less

Overview of SBIR Phase II Work on Hollow Graphite Fibers

NASA Technical Reports Server (NTRS)

Stallcup, Michael; Brantley, Lott W. (Technical Monitor)

2001-01-01

Ultra-Lightweight materials are enabling for producing space based optical components and support structures. Heretofore, innovative designs using existing materials has been the approach to produce lighter-weight optical systems. Graphite fiber reinforced composites, because of their light weight, have been a material of frequent choice to produce space based optical components. Hollow graphite fibers would be lighter than standard solid graphite fibers and, thus, would save weight in optical components. The Phase I SBIR program demonstrated it is possible to produce hollow carbon fibers that have strengths up to 4.2 GPa which are equivalent to commercial fibers, and composites made from the hollow fibers had substantially equivalent composite strengths as commercial fiber composites at a 46% weight savings. The Phase II SBIR program will optimize processing and properties of the hollow carbon fiber and scale-up processing to produce sufficient fiber for fabricating a large ultra-lightweight mirror for delivery to NASA. Information presented here includes an overview of the strength of some preliminary hollow fibers, photographs of those fibers, and a short discussion of future plans.

Nano-particle modified stationary phases for high-performance liquid chromatography.

PubMed

Nesterenko, Ekaterina P; Nesterenko, Pavel N; Connolly, Damian; He, Xiaoyun; Floris, Patrick; Duffy, Emer; Paull, Brett

2013-08-07

This review covers the latest developments and applications of nano-materials in stationary phase development for various modes of high-performance liquid chromatography. Specific attention is placed upon the development of new composite phases, including the synthetic and immobilisation strategies used, to produce either encapsulated nano-particles, or surface attached nano-particles, layers, coatings and other structures. The resultant chromatographic applications, where applicable, are discussed with comment upon enhanced selectivity and/or efficiency of the nano-particle modified phases, where such effects have been identified. In the main this review covers developments over the past five years and is structured according to the nature of the nano-particles themselves, including carbonaceous, metallic, inorganic, and organopolymer based materials.

Thermoplastic coating of carbon fibers

NASA Technical Reports Server (NTRS)

Edie, D. D.; Lickfield, G. C.; Allen, L. E.; Mccollum, J. R.

1989-01-01

A continuous powder coating system was developed for coating carbon fiber with LaRC-TPI (Langley Research Center-Thermoplastic Polyimide), a high-temperature thermoplastic polymide invented by NASA-Langley. The coating line developed used a pneumatic fiber spreader to separate the individual fibers. The polymer was applied within a recirculating powder coating chamber then melted using a combination of direct electrical resistance and convective heating to make it adhere to the fiber tow. The tension and speed of the line were controlled with a dancer arm and an electrically driven fiber wind-up and wind-off. The effects of heating during the coating process on the flexibility of the prepreg produced were investigated. The uniformity with which the fiber tow could be coated with polymer also was examined. Composite specimens were fabricated from the prepreg and tested to determine optimum process conditions. The study showed that a very uniform and flexible prepeg with up to 50 percent by volume polymer could be produced with this powder coating system. The coating line minimized powder loss and produced prepeg in lengths of up to 300 m. The fiber spreading was found to have a major effect on the coating uniformity and flexibility. Though test results showed low composite tensile strengths, analysis of fracture surfaces under scanning electron microscope indicated that fiber/matrix adhesion was adequate.

Diffraction efficiency growth of nano-scale holographic recording produced in a corona discharge

NASA Astrophysics Data System (ADS)

Bodurov, I.; Yovcheva, T.; Vlaeva, I.; Viraneva, A.; Todorov, R.; Spassov, G.; Sainov, S.

2012-12-01

The nano-scale holographic gratings ware recorded in 29 nm and 56 nm thick As2S3 films. The chalcogenide layers were deposited on a transparent chromium electrode with thickness 10 nm, produced on a glass substrate. Both chromium and chalcogenide films were deposited in one vacuum cycle by e-beam and thermal evaporation, respectively. The diode 532 nm diode laser was used as a light source in the present holographic experiments. The total internal reflection arrangement (Stetson-Nassenstein) was used in holographic recordings. The reference beam was totally reflected from the air-As2S3 boundary surface by an input glass prism. The object beam was normally incident on the recording medium. The corona charging was performed by a needle fixed at the distance of 1 cm from the holographic recording medium by applying a - 5 kV voltage. The diffraction efficiency increased from 9 to 30 times when the corona discharge was applied during the holographic recording, in comparison to the uncharged recording. The possible reason of the observed effect is discussed on the basis of the Franz-Keldysh effect and Moss rule.

Effect of Al-TiB Addition on the Mechanical Properties and Microstructure of Al-ADC12/NanoSiC Produced by Stir Casting Methods

NASA Astrophysics Data System (ADS)

Dhaneswara, D.; Zulfia, A.; Pramudita, T. P.; Ferdian, D.; Utomo, B. W.

2018-03-01

Addition of Ti-B grain refiner in Al-ADC12/nanoSiC composite results in improvement of tensile strength, hardness, and wear resistance through grain refinement. In this research, composite of Al-ADC12/nano SiC (0.15 %vf) with variations of TiB respectively (0.0), (0.02), (0.04), (0.06), dan (0.08) wt% were produced by stir casting. 10% of Mg were added to promote wettability between reinforce and matrix. It was found the best addition of TiB is 0.04 wt% Ti-B which results 135,9 MPa in tensile strength, 46 HRB in hardness, and 1.47x10-5 mm3/s as wear rate. The increase in mechanical properties of composites mainly because of Al3Ti acts as nucleants which initiates the grain refinement and the existence of MgAl2O4 phase indicates an interphase between nano SiC and ADC12 matrix. However, the increase of Ti-B addition after optimum number gives no significant results. High composition of iron and magnesium addition will form intermetallic phase β-Fe, π-Fe, and Mg2Si.

Silicon carbide fibers and articles including same

DOEpatents

Garnier, John E; Griffith, George W

2015-01-27

Methods of producing silicon carbide fibers. The method comprises reacting a continuous carbon fiber material and a silicon-containing gas in a reaction chamber at a temperature ranging from approximately 1500.degree. C. to approximately 2000.degree. C. A partial pressure of oxygen in the reaction chamber is maintained at less than approximately 1.01.times.10.sup.2 Pascal to produce continuous alpha silicon carbide fibers. Continuous alpha silicon carbide fibers and articles formed from the continuous alpha silicon carbide fibers are also disclosed.

Transgenic cotton over-producing spinach sucrose phosphate synthase showed enhanced leaf sucrose synthesis and improved fiber quality under controlled environmental conditions.

PubMed

Haigler, Candace H; Singh, Bir; Zhang, Deshui; Hwang, Sangjoon; Wu, Chunfa; Cai, Wendy X; Hozain, Mohamed; Kang, Wonhee; Kiedaisch, Brett; Strauss, Richard E; Hequet, Eric F; Wyatt, Bobby G; Jividen, Gay M; Holaday, A Scott

2007-04-01

Prior data indicated that enhanced availability of sucrose, a major product of photosynthesis in source leaves and the carbon source for secondary wall cellulose synthesis in fiber sinks, might improve fiber quality under abiotic stress conditions. To test this hypothesis, a family of transgenic cotton plants (Gossypium hirsutum cv. Coker 312 elite) was produced that over-expressed spinach sucrose-phosphate synthase (SPS) because of its role in regulation of sucrose synthesis in photosynthetic and heterotrophic tissues. A family of 12 independent transgenic lines was characterized in terms of foreign gene insertion, expression of spinach SPS, production of spinach SPS protein, and development of enhanced extractable V (max) SPS activity in leaf and fiber. Lines with the highest V (max) SPS activity were further characterized in terms of carbon partitioning and fiber quality compared to wild-type and transgenic null controls. Leaves of transgenic SPS over-expressing lines showed higher sucrose:starch ratio and partitioning of (14)C to sucrose in preference to starch. In two growth chamber experiments with cool nights, ambient CO(2) concentration, and limited light below the canopy, the transgenic line with the highest SPS activity in leaf and fiber had higher fiber micronaire and maturity ratio associated with greater thickness of the cellulosic secondary wall.

An all fiber-optic multi-parameter structure health monitoring system

DOE PAGES

Hu, Chennan; Yu, Zhihao; Wang, Anbo

2016-08-24

In this article, we present an all fiber-optics based multi-parameter structure health monitoring system, which is able to monitor strain, temperature, crack and thickness of metal structures. This system is composed of two optical fibers, one for laser-acoustic excitation and the other for acoustic detection. A nano-second 1064 nm pulse laser was used for acoustic excitation and a 2 mm fiber Bragg grating was used to detect the acoustic vibration. The feasibility of this system was demonstrated on an aluminum test piece by the monitoring of the temperature, strain and thickness changes, as well as the appearance of an artificialmore » crack. The multiplexing capability of this system was also preliminarily demonstrated.« less

An all fiber-optic multi-parameter structure health monitoring system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hu, Chennan; Yu, Zhihao; Wang, Anbo

In this article, we present an all fiber-optics based multi-parameter structure health monitoring system, which is able to monitor strain, temperature, crack and thickness of metal structures. This system is composed of two optical fibers, one for laser-acoustic excitation and the other for acoustic detection. A nano-second 1064 nm pulse laser was used for acoustic excitation and a 2 mm fiber Bragg grating was used to detect the acoustic vibration. The feasibility of this system was demonstrated on an aluminum test piece by the monitoring of the temperature, strain and thickness changes, as well as the appearance of an artificialmore » crack. The multiplexing capability of this system was also preliminarily demonstrated.« less

A model of optical trapping cold atoms using a metallic nano wire with surface plasmon effect

NASA Astrophysics Data System (ADS)

Thi Phuong Lan, Nguyen; Thi Nga, Do; Viet, Nguyen Ai

2016-06-01

In this work, we construct a new model of optical trapping cold atoms with a metallic nano wire by using surface plasmon effect generated by strong field of laser beams. Using the skin effect, we send a strong oscillated electromagnetic filed through the surface of a metallic nano wire. The local field generated by evanescent effect creates an effective attractive potential near the surface of metallic nano wires. The consideration of some possible boundary and frequency conditions might lead to non-trivial bound state solution for a cold atom. We discus also the case of the laser reflection optical trap with shell-core design, and compare our model with another recent schemes of cold atom optical traps using optical fibers and carbon nanotubes.

Nano-Satellite Avionics

NASA Technical Reports Server (NTRS)

Culver, Harry

1999-01-01

Abstract NASA's Goddard Space Flight Center (GSFC) is currently developing a new class of satellites called the nano-satellite (nano-sat). A major objective of this development effort is to provide the technology required to enable a constellation of tens to hundreds of nano-satellites to make both remote and in-situ measurements from space. The Nano-sat will be a spacecraft weighing a maximum of 10 kg, including the propellant mass, and producing at least 5 Watts of power to operate the spacecraft. The electronics are required to survive a total radiation dose rate of 100 krads for a mission lifetime of two years. There are many unique challenges that must be met in order to develop the avionics for such a spacecraft. The first challenge is to develop an architecture that will operate on the allotted 5 Watts and meet the diverging requirements of multiple missions. This architecture will need to incorporate a multitude of new advanced microelectronic technologies. The microelectronics developed must be a modular and scalable packaging of technology to solve the problem of developing a solution to both reduce cost and meet the requirements of various missions. This development will utilize the most cost effective approach, whether infusing commercially driven semiconductor devices into spacecraft applications or partnering with industry to design and develop low cost, low power, low mass, and high capacity data processing devices. This paper will discuss the nano-sat architecture and the major technologies that will be developed. The major technologies that will be covered include: (1) Light weight Low Power Electronics Packaging, (2) Radiation Hard/Tolerant, Low Power Processing Platforms, (3) High capacity Low Power Memory Systems (4) Radiation Hard reconfiguragble field programmable gate array (rFPGA)

Comparative analysis of the digestibility of sewage fine sieved fraction and hygiene paper produced from virgin fibers and recycled fibers.

PubMed

Ghasimi, Dara S M; Zandvoort, Marcel H; Adriaanse, Michiel; van Lier, Jules B; de Kreuk, Merle

2016-07-01

Sewage fine sieved fraction (FSF) is a heterogeneous substrate consisting of mainly toilet paper fibers sequestered from municipal raw sewage by a fine screen. In earlier studies, a maximum biodegradation of 62% and 57% of the sewage FSF was found under thermophilic (55°C) and mesophilic (35°C) conditions, respectively. In order to research this limited biodegradability of sewage FSF, this study investigates the biodegradation of different types of cellulosic fibers-based hygiene papers including virgin fibers based toilet paper (VTP), recycled fiber based toilet paper (RTP), virgin pulp for paper production (VPPP) as a raw material, as well as microcrystalline cellulose (MCC) as a kind of fiberless reference material. The anaerobic biodegradation or digestibility tests were conducted under thermophilic and mesophilic conditions. Results of the experiments showed different biomethane potential (BMP) values for each tested cellulose fiber-based substrate, which might be associated with the physical characteristics of the fibers, type of pulping, presence of lignin encrusted fibers, and/or the presence of additive chemicals and refractory compounds. Higher hydrolysis rates (Kh), higher specific methane production rates (SMPR) and shorter required incubation times to achieve 90% of the BMP (t90%CH4), were achieved under thermophilic conditions for all examined substrates compared to the mesophilic ones. Furthermore, the biodegradability of all employed cellulose fiber-based substrates was in the same range, 38-45%, under both conditions and less than the observed FSF biodegradability, i.e. 57-62%. MCC achieved the highest BMP and biodegradability, 86-91%, among all cellulosic substrates. Copyright © 2016 Elsevier Ltd. All rights reserved.

Pulse electrochemical meso/micro/nano ultraprecision machining technology.

PubMed

Lee, Jeong Min; Kim, Young Bin; Park, Jeong Woo

2013-11-01

This study demonstrated meso/micro/nano-ultraprecision machining through electrochemical reactions using intermittent DC pulses. The experiment focused on two machining methods: (1) pulse electrochemical polishing (PECP) of stainless steel, and (2) pulse electrochemical nano-patterning (PECNP) on a silicon (Si) surface, using atomic force microscopy (AFM) for fabrication. The dissolution reaction at the stainless steel surface following PECP produced a very clean, smooth workpiece. The advantages of the PECP process included improvements in corrosion resistance, deburring of the sample surface, and removal of hydrogen from the stainless steel surface as verified by time-of-flight secondary-ion mass spectrometry (TOF-SIMS). In PECNP, the electrochemical reaction generated within water molecules produced nanoscale oxide textures on a Si surface. Scanning probe microscopy (SPM) was used to evaluate nanoscale-pattern processing on a Si wafer surface produced by AFM-PECNP For both processes using pulse electrochemical reactions, three-dimensional (3-D) measurements and AFM were used to investigate the changes on the machined surfaces. Preliminary results indicated the potential for advancing surface polishing techniques and localized micro/nano-texturing technology using PECP and PECNP processes.

Optical fiber sensor having an active core

NASA Technical Reports Server (NTRS)

Egalon, Claudio Oliveira (Inventor); Rogowski, Robert S. (Inventor)

1993-01-01

An optical fiber is provided. The fiber is comprised of an active fiber core which produces waves of light upon excitation. A factor ka is identified and increased until a desired improvement in power efficiency is obtained. The variable a is the radius of the active fiber core and k is defined as 2 pi/lambda wherein lambda is the wavelength of the light produced by the active fiber core. In one embodiment, the factor ka is increased until the power efficiency stabilizes. In addition to a bare fiber core embodiment, a two-stage fluorescent fiber is provided wherein an active cladding surrounds a portion of the active fiber core having an improved ka factor. The power efficiency of the embodiment is further improved by increasing a difference between the respective indices of refraction of the active cladding and the active fiber core.

Hybrid matrix fiber composites

DOEpatents

Deteresa, Steven J.; Lyon, Richard E.; Groves, Scott E.

2003-07-15

Hybrid matrix fiber composites having enhanced compressive performance as well as enhanced stiffness, toughness and durability suitable for compression-critical applications. The methods for producing the fiber composites using matrix hybridization. The hybrid matrix fiber composites include two chemically or physically bonded matrix materials, whereas the first matrix materials are used to impregnate multi-filament fibers formed into ribbons and the second matrix material is placed around and between the fiber ribbons that are impregnated with the first matrix material and both matrix materials are cured and solidified.

Biochar Produced from Anaerobically Digested Fiber Reduces Phosphorus in Dairy Lagoons

DOE Office of Scientific and Technical Information (OSTI.GOV)

Streubel, Jason D.; Collins, Harold P.; Tarara, Julie M.

2012-01-01

This study evaluated the use of biochar produced from anaerobic digester dairy fiber (ADF) to sequester phosphorus (P) from dairy lagoons. The ADF was collected from a plugged flow digester, air-dried to <8% water content, and pelletized. Biochar was produced by slow pyrolysis in a barrel retort. The potential of biochar to reduce P in the anaerobic digester effluent (ADE) was assessed in small-scale filter systems through which the effluent was circulated. Biochar sequestered an average of 381 mg L -1 P from the ADE, and 4 g L -1 ADF was captured as a coating on the biochar. Theremore » was an increase of total (1.9 g kg -1), Olsen (763 mg kg -1), and water-extractable P (914 mg kg -1) bound to the biochar after 15 d of filtration. This accounted for a recovery of 32% of the P in the ADE. The recovered P on the biochar was analyzed using 31P nuclear magnetic resonance for P speciation, which confirmed the recovery of inorganic orthophosphate after liquid extraction of the biochar and the presence of inextractable Ca-P in the solid state. The inorganic phosphate was sequestered on the biochar through physical and weak chemical bonding. Finally, results indicate that biochar could be a beneficial component to P reduction in the dairy system.« less

Evaluation of elastic modulus and hardness of crop stalks cell walls by nano-indentation

Treesearch

Yan Wu; Siqun Wang; Dingguo Zhou; Cheng Xing; Yang Zhang; Zhiyong Cai

2010-01-01

Agricultural biomaterials such as crop stalks are natural sources of cellulosic fiber and have great potential as reinforced materials in bio-composites. In order to evaluate their potential as materials for reinforcement, the nano-mechanical properties of crop-stalk cell walls, i.e. those of cotton (Gossypium herbaceu) stalk, soybean (Glycine max) stalk, cassava (...

Carbide coated fibers in graphite-aluminum composites

NASA Technical Reports Server (NTRS)

Imprescia, R. J.; Levinson, L. S.; Reiswig, R. D.; Wallace, T. C.; Williams, J. M.

1975-01-01

Thin, uniform coats of titanium carbide, deposited on graphite fibers by chemical vapor deposition with thicknesses up to approximately 0.1 microns were shown to improve fiber strength significantly. For greater thicknesses, strength was degraded. The coats promote wetting of the fibers and infiltration of the fiber yarns with aluminum alloys, and act as protective barriers to inhibit reaction between the fibers and the alloys. Chemical vapor deposition was used to produce silicon carbide coats on graphite fibers. In general, the coats were nonuniform and were characterized by numerous surface irregularities. Despite these irregularities, infiltration of these fibers with aluminum alloys was good. Small graphite-aluminum composite samples were produced by vacuum hot-pressing of aluminum-infiltrated graphite yarn at temperatures above the metal liquidus.

Nanoparticle coated optical fibers for single microbubble generation

NASA Astrophysics Data System (ADS)

Pimentel-Domínguez, Reinher; Hernández-Cordero, Juan

2011-09-01

The study of bubbles and bubbly flows is important in various fields such as physics, chemistry, medicine, geophysics, and even the food industry. A wide variety of mechanical and acoustic techniques have been reported for bubble generation. Although a single bubble may be generated with these techniques, controlling the size and the mean lifetime of the bubble remains a difficult task. Most of the optical methods for generation of microbubbles involve high-power pulsed laser sources focused in absorbing media such as liquids or particle solutions. With these techniques, single micron-sized bubbles can be generated with typical mean lifetimes ranging from nano to microseconds. The main problem with these bubbles is their abrupt implosion: this produces a shock wave that can potentially produce damages on the surroundings. These effects have to be carefully controlled in biological applications and in laser surgery, but thus far, not many options are available to effectively control micron-size bubble growth. In this paper, we present a new technique to generate microbubbles in non-absorbing liquids. In contrast to previous reports, the proposed technique uses low-power and a CW radiation from a laser diode. The laser light is guided through an optical fiber whose output end has been coated with nanostructures. Upon immersing the tip of the fiber in ethanol or water, micron-size bubbles can be readily generated. With this technique, bubble growth can be controlled through adjustments on the laser power. We have obtained micron-sized bubbles with mean lifetimes in the range of seconds. Furthermore, the generated bubbles do not implode, as verified with a high-speed camera and flow visualization techniques.

Tunable far-infrared plasmonically induced transparency in graphene based nano-structures

NASA Astrophysics Data System (ADS)

Dolatabady, Alireza; Granpayeh, Nosrat

2018-07-01

In this paper, a structure is proposed to show the phenomenon of tunable far-infrared plasmonically induced transparency. The structure includes a nano-ribbon waveguide side-coupled to nano-stub resonators. The realized effect is due to the coupling between the consecutive nano-stub resonators spaced in properly designed distances, providing a constructive interference in the virtually created Fabry–Perot cavity. Due to the Fabry–Perot like cavity created between two consecutive nano-stubs, periodic values of nano-stubs separation can produce transparency windows. Increasing the number of nano-stubs would increase the number of transparency windows in different frequencies. The structure is theoretically investigated and numerically simulated by using the finite difference time domain method. Owing to the chemical potential dependency of graphene conductivity, the transparency windows can be actively tuned. The proposed component can be extensively utilized in nano-scale switching and slow-light systems.

Thermally modulated nano-trampoline material as smart skin for gas molecular mass detection

NASA Astrophysics Data System (ADS)

Xia, Hua

2012-06-01

Conventional multi-component gas analysis is based either on laser spectroscopy, laser and photoacoustic absorption at specific wavelengths, or on gas chromatography by separating the components of a gas mixture primarily due to boiling point (or vapor pressure) differences. This paper will present a new gas molecular mass detection method based on thermally modulated nano-trampoline material as smart skin for gas molecular mass detection by fiber Bragg grating-based gas sensors. Such a nanomaterial and fiber Bragg grating integrated sensing device has been designed to be operated either at high-energy level (highly thermal strained status) or at low-energy level (low thermal strained status). Thermal energy absorption of gas molecular trigs the sensing device transition from high-thermal-energy status to low-thermal- energy status. Experiment has shown that thermal energy variation due to gas molecular thermal energy absorption is dependent upon the gas molecular mass, and can be detected by fiber Bragg resonant wavelength shift with a linear function from 17 kg/kmol to 32 kg/kmol and a sensitivity of 0.025 kg/kmol for a 5 micron-thick nano-trampoline structure and fiber Bragg grating integrated gas sensing device. The laboratory and field validation data have further demonstrated its fast response characteristics and reliability to be online gas analysis instrument for measuring effective gas molecular mass from single-component gas, binary-component gas mixture, and multi-gas mixture. The potential industrial applications include fouling and surge control for gas charge centrifugal compressor ethylene production, gas purity for hydrogen-cooled generator, gasification for syngas production, gasoline/diesel and natural gas fuel quality monitoring for consumer market.

Physical and mechanical properties of PMMA bone cement reinforced with nano-sized titania fibers.

PubMed

Khaled, S M Z; Charpentier, Paul A; Rizkalla, Amin S

2011-02-01

X-ray contrast medium (BaSO(4) or ZrO(2)) used in commercially available PMMA bone cements imparts a detrimental effect on mechanical properties, particularly on flexural strength and fracture toughness. These lower properties facilitate the chance of implant loosening resulting from cement mantle failure. The present study was performed to examine the mechanical properties of a commercially available cement (CMW1) by introducing novel nanostructured titania fibers (n-TiO(2) fibers) into the cement matrix, with the fibers acting as a reinforcing phase. The hydrophilic nature of the n-TiO(2) fibers was modified by using a bifunctional monomer, methacrylic acid. The n-TiO(2) fiber content of the cement was varied from 0 to 2 wt%. Along with the mechanical properties (fracture toughness (K (IC)), flexural strength (FS), and flexural modulus (FM)) of the reinforced cements the following properties were investigated: complex viscosity-versus-time, maximum polymerization temperature (T (max)), dough time (t (dough)), setting time (t (set)), radiopacity, and in vitro biocompatibility. On the basis of the determined mechanical properties, the optimized composition was found at 1 wt% n-TiO(2) fibers, which provided a significant increase in K (IC) (63%), FS (20%), and FM (22%), while retaining the handling properties and in vitro biocompatibility compared to that exhibited by the control cement (CMW1). Moreover, compared to the control cement, there was no significant change in the radiopacity of any of the reinforced cements at p = 0.05. This study demonstrated a novel pathway to augment the mechanical properties of PMMA-based cement by providing an enhanced interfacial interaction and strong adhesion between the functionalized n-TiO( 2) fibers and PMMA matrix, which enhanced the effective load transfer within the cement.

Enhanced radiation resistant fiber optics

DOEpatents

Lyons, Peter B.; Looney, Larry D.

1993-01-01

A process for producing an optical fiber having enhanced radiation resitance is provided, the process including maintaining an optical fiber within a hydrogen-containing atmosphere for sufficient time to yield a hydrogen-permeated optical fiber having an elevated internal hydrogen concentration, and irradiating the hydrogen-permeated optical fiber at a time while the optical fiber has an elevated internal hydrogen concentration with a source of ionizing radiation. The radiation source is typically a cobalt-60 source and the fiber is pre-irradiated with a dose level up to about 1000 kilorads of radiation.

Enhanced radiation resistant fiber optics

DOEpatents

Lyons, P.B.; Looney, L.D.

1993-11-30

A process for producing an optical fiber having enhanced radiation resistance is provided, the process including maintaining an optical fiber within a hydrogen-containing atmosphere for sufficient time to yield a hydrogen-permeated optical fiber having an elevated internal hydrogen concentration, and irradiating the hydrogen-permeated optical fiber at a time while the optical fiber has an elevated internal hydrogen concentration with a source of ionizing radiation. The radiation source is typically a cobalt-60 source and the fiber is pre-irradiated with a dose level up to about 1000 kilorads of radiation. 4 figures.

Fabrication of nano-gap electrode arrays by the construction and selective chemical etching of nano-crosswire stacks

NASA Technical Reports Server (NTRS)

Prokopuk, Nicholas (Inventor); Son, Kyung-Ah (Inventor)

2008-01-01

Methods of fabricating nano-gap electrode structures in array configurations, and the structures so produced. The fabrication method involves depositing first and second pluralities of electrodes comprising nanowires using processes such as lithography, deposition of metals, lift-off processes, and chemical etching that can be performed using conventional processing tools applicable to electronic materials processing. The gap spacing in the nano-gap electrode array is defined by the thickness of a sacrificial spacer layer that is deposited between the first and second pluralities of electrodes. The sacrificial spacer layer is removed by etching, thereby leaving a structure in which the distance between pairs of electrodes is substantially equal to the thickness of the sacrificial spacer layer. Electrode arrays with gaps measured in units of nanometers are produced. In one embodiment, the first and second pluralities of electrodes are aligned in mutually orthogonal orientations.

Optical properties study of nano-composite filled D shape photonic crystal fibre

NASA Astrophysics Data System (ADS)

Udaiyakumar, R.; Mohamed Junaid, K. A.; Janani, T.; Maheswar, R.; Yupapin, P.; Amiri, I. S.

2018-06-01

With the nano-composite materials gaining momentum in the optical field, a new nano-composite filled D shape Photonic Crystal Fiber (PCF) is designed and the various optical properties are investigated with help of Finite Element Method. In the proposed structure the D-shape PCF is made up of silica with embedded silver nanoparticles and air holes are distributed along the fibre. The designed fibre shows various optical properties such as dispersion, birefringence, beat length and loss with respect to wavelength and compared with different filling factor like 0.1, 0.3 and 0.5. From our estimation and comparative analysis, it has been proved that the fibre loss has been decreased with increasing filling factor. Further this also showed flat dispersion at maximum filling factor.

Plasmonic structure: fiber grating formed by gold nanorods on a tapered fiber.

PubMed

Trevisanutto, J O; Linhananta, A; Das, G

2016-12-15

The authors demonstrated the fabrication of a fiber Bragg grating-like plasmonic nanostructure on the surface of a tapered optical fiber using gold nanorods (GNRs). A multimode optical fiber with core and cladding diameters of 105 and 125 μm, respectively, was used to make a tapered fiber using a dynamic etching process. The tip diameter was ∼100  nm. Light from a laser was coupled to the untapered end of the fiber, which produced a strong evanescent field around the tapered section of the fiber. The gradient force due to the evanescent field trapped the GNRs on the surface of the tapered fiber. The authors explored possible causes of the GNR distribution. The plasmonic structure will be a good candidate for sensing based on surface enhanced Raman scattering.

Sub-10-nm suspended nano-web formation by direct laser writing

NASA Astrophysics Data System (ADS)

Wang, Sihao; Yu, Ye; Liu, Hailong; Lim, Kevin T. P.; Madurai Srinivasan, Bharathi; Zhang, Yong Wei; Yang, Joel K. W.

2018-06-01

A diffraction-limited three-dimensional (3D) direct laser writing (DLW) system based on two-photon polymerization can routinely pattern structures at the 100 nm length scale. Several schemes have been developed to improve the patterning resolution of 3D DLW but often require customized resist formulations or multi-wavelength exposures. Here, we introduce a scheme to produce suspended nano-webs with feature sizes below 10 nm in IP-Dip resist using sub-threshold exposure conditions in a commercial DLW system. The narrowest suspended lines (nano-webs) measured 7 nm in width. Larger ∼20 nm nano-webs were patterned with ∼80% yield at increased laser powers. In addition, closely spaced nano-gaps with a center-to-center distance of 33 nm were produced by patterning vertically displaced suspended lines followed by metal deposition and liftoff. We provide hypotheses and present preliminary results for a mechanism involving the initiation of a percolative path and a strain-induced narrowing in the nano-web formation. Our approach allows selective features to be patterned with dimensions comparable to the sub-10 nm patterning capability of electron-beam lithography (EBL).

Tunable fiber Bragg grating ring lasers using macro fiber composite actuators

NASA Astrophysics Data System (ADS)

Geddis, Demetris L.; Allison, Sidney G.; Shams, Qamar A.

2006-10-01

The research reported herein includes the fabrication of a tunable optical fiber Bragg grating (FBG) fiber ring laser (FRL)1 from commercially available components as a high-speed alternative tunable laser source for NASA Langley's optical frequency domain reflectometer (OFDR) interrogator, which reads low reflectivity FBG sensors. A Macro-Fiber Composite (MFC) actuator invented at NASA Langley Research Center (LaRC) was selected to tune the laser. MFC actuators use a piezoelectric sheet cut into uniaxially aligned rectangular piezo-fibers surrounded by a polymer matrix and incorporate interdigitated electrodes to deliver electric fields along the length of the piezo-fibers. This configuration enables MFC actuators to produce displacements larger than the original uncut piezoelectric sheet. The FBG filter was sandwiched between two MFC actuators, and when strained, produced approximately 3.62 nm of wavelength shift in the FRL when biasing the MFC actuators from -500 V to 2000 V. This tunability range is comparable to that of other tunable lasers and is adequate for interrogating FBG sensors using OFDR technology. Three different FRL configurations were studied. Configuration A examined the importance of erbium-doped fiber length and output coupling. Configuration B demonstrated the importance of the FBG filter. Configuration C added an output coupler to increase the output power and to isolate the filter. Only configuration C was tuned because it offered the best optical power output of the three configurations. Use of Plastic Optical Fiber (POF) FBG's holds promise for enhanced tunability in future research.

Gasifiable carbon-graphite fibers

NASA Technical Reports Server (NTRS)

Humphrey, Marshall F. (Inventor); Ramohalli, Kumar N. R. (Inventor); Dowler, Warren L. (Inventor)

1982-01-01

Fine, carbon-graphite fibers do not combust during the combustion of a composite and are expelled into the air as fine conductive particles. Coating of the fibers with a salt of a metal having a work function below 4.2 eV such as an alkaline earth metal salt, e.g., calcium acetate, catalytically enhances combustion of the fibers at temperatures below 1000.degree. C. such that the fibers self-support combustion and burn to produce a non-conductive ash. Fire-polishing the fibers before application of the coating is desirable to remove sizing to expose the carbon surface to the catalyst.

Producing colloids with microfluidics

NASA Astrophysics Data System (ADS)

Pannacci, Nicolas; Willaime, Herve; Tabeling, Patrick

2008-11-01

Submicronic emulsions are commonly used in pharmaceutical, food, cosmetic and material industries. Standard microfluidic tool is particularly convenient to produce in a very controlled way either droplets of typical diameter ranging from 10 to 300 microns with a perfect monodispersity (<3%), or double emulsions as well as double droplets (janus). We report the use of microfluidic devices to produce submicronic objects. We use a hydrodynamic flow-focusing that has the advantage to generate nanodrops in a way that is slightly dependent on the fluids used. The control on such a flow authorizes the adjustment of the diameter of the colloids formed. We will show brownian particles from 860 nm to 1.3 μm in diameter obtained in such way and their clustering into crystals thanks to their high monodispersity. These first experimental results are very promising and make evident the great potential of micro and nano-fluidics to produce nano-emulsions or colloids with very controlled size that metamaterials can require.

Preparation of nano fluids by mechanical method

NASA Astrophysics Data System (ADS)

Boopathy, J.; Pari, R.; Kavitha, M.; Angelo, P. C.

2012-07-01

Nanofluids are conventional heat transfer fluids that contain nano particles of metals, oxides, carbides, nitrides, or nanotubes. Nanofluids exhibit enhanced thermal conductivity and heat transfer coefficients compared to the base fluids. This paper presents the procedure for preparing nanofluids consisting of Copper and Aluminium nano powders in base fluids. Copper and Aluminium nano powders were produced by planetary ball wet milling at 300rpm for 50hrs. Toluene was added to ensure wet milling. These powders were characterized in XRD and SEM for their purity, particle size and shape. The XRD results confirmed the final particle sizes of Copper and Aluminium in the nano range. Then the 0.01 gm of nano metal powders was added in 150 ml of double distilled water and magnetic stirring was done at 1500 rpm for 15 minutes. Sodium lauryl sulphate (0.05%) was added in water as surfactant to ensure the stability of the dispersion. Ultrasonication in the 3000 watts bath was done for 10 minutes to enhance the uniform dispersion of metal powders in water. The pH, dynamic viscosity, ionic conductivity and the stability of the fluids were determined for further usage of synthesized nanofluids as coolant during grinding operation.

Biosoftening of coir fiber using selected microorganisms.

PubMed

Rajan, Akhila; Senan, Resmi C; Pavithran, C; Abraham, T Emilia

2005-12-01

Coir fiber belongs to the group of hard structural fibers obtained from coconut husk. As lignin is the main constituent of coir responsible for its stiffness, microbes that selectively remove lignin without loss of appreciable amounts of cellulose are extremely attractive in biosoftening. Five isolated strains were compared with known strains of bacteria and fungi. The raw fiber treated with Pseudomonas putida and Phanerocheate chrysosporium produced better softened fiber at 30+/-2 degrees C and neutral pH. FeSO4 and humic acid were found to be the best inducers for P. chrysosporium and P. putida, respectively, while sucrose and dextrose were the best C-sources for both. Biosoftening of unretted coir fibers was more advantageous than the retted fibers. Unlike the weak chemically softened fiber, microbial treatment produced soft, whiter fibers having better tensile strength and elongation (44.6-44.8%) properties. Scanning electron microscopy photos showed the mycelia penetrating the pores of the fiber, removing the tylose plug and degrading lignin.

IR fiber temperature sensing system

NASA Technical Reports Server (NTRS)

Tran, D. C.; Levin, K. H.; Mossadegh, R.; Koontz, Steve

1988-01-01

Infrared fiber optic pyrometry has become a practical reality using improved strength fluoride glass fibers. The addition of a plastic coating and rugged cabling allows the fibers to be used in the field. A detailed theoretical model of the infrared fiber optic pyrometer (non-contact or radiative thermometer) has been derived and compared with data produced by a prototype fluoride glass fiber radiative thermometer. Excellent agreement was obtained between theory and experiment over a temperature range of 30 to 700 C.

Activated carbon fibers and engineered forms from renewable resources

DOEpatents

Baker, Frederick S

2013-02-19

A method of producing activated carbon fibers (ACFs) includes the steps of providing a natural carbonaceous precursor fiber material, blending the carbonaceous precursor material with a chemical activation agent to form chemical agent-impregnated precursor fibers, spinning the chemical agent-impregnated precursor material into fibers, and thermally treating the chemical agent-impregnated precursor fibers. The carbonaceous precursor material is both carbonized and activated to form ACFs in a single step. The method produces ACFs exclusive of a step to isolate an intermediate carbon fiber.

Activated carbon fibers and engineered forms from renewable resources

DOEpatents

Baker, Frederick S.

2010-06-01

A method of producing activated carbon fibers (ACFs) includes the steps of providing a natural carbonaceous precursor fiber material, blending the carbonaceous precursor material with a chemical activation agent to form chemical agent-impregnated precursor fibers, spinning the chemical agent-impregnated precursor material into fibers, and thermally treating the chemical agent-impregnated precursor fibers. The carbonaceous precursor material is both carbonized and activated to form ACFs in a single step. The method produces ACFs exclusive of a step to isolate an intermediate carbon fiber.

An all-fiber partial discharge monitoring system based on both intrinsic fiber optic interferometry sensor and fluorescent fiber

NASA Astrophysics Data System (ADS)

Yin, Zelin; Zhang, Ruirui; Tong, Jie; Chen, Xi

2013-12-01

Partial discharges (PDs) are an electrical phenomenon that occurs within a transformer whenever the voltage stress is sufficient to produce ionization in voids or inclusions within a solid dielectric, at conductor/dielectric interfaces, or in bubbles within liquid dielectrics such as oil; high-frequency transient current discharges will then appear repeatedly and will progressively deteriorate the insulation, ultimately leading to breakdown. Fiber sensor has great potential on the partial discharge detection in high-voltage equipment for its immunity to electromagnetic interference and it can take direct measurement in the high voltage equipment. The energy released in PDs produces a number of effects, resulting in flash, chemical and structural changes and electromagnetic emissions and so on. Acoustic PD detection is based on the mechanical pressure wave emitted from the discharge and fluorescent fiber PD detection is based on the emitted light produced by ionization, excitation and recombination processes during the discharge. Both of the two methods have the shortage of weak anti-interference capacity in the physical environment, like thunder or other sound source. In order to avoid the false report, an all-fiber combined PD detection system of the two methods is developed in this paper. In the system the fluorescent fiber PD sensor is considered as a reference signal, three F-P based PD detection sensors are used to both monitor the PD intensity and calculate the exact position of the discharge source. Considering the wave band of the F-P cavity and the fluorescent probe are quite different, the reflection spectrum of the F-P cavity is in the infrared region, however the fluorescent probe is about 600nm to 700nm, thus the F-P sensor and fluorescent fiber probe can be connected in one fiber and the reflection light can be detected by two different detectors without mutual interference. The all-fiber partial discharge monitoring system not only can detect the PDs

In vivo synthesis of nano-selenium by Tetrahymena thermophila SB210.

PubMed

Cui, Yin-Hua; Li, Ling-Li; Zhou, Nan-Qing; Liu, Jing-Hua; Huang, Qing; Wang, Hui-Juan; Tian, Jie; Yu, Han-Qing

2016-12-01

Nano-selenium has a great potential to be used in chemical, biological, medical and environmental fields. Biological methods for nano-selenium synthesis have attracted wide interests, because they can be operated at ambient temperature and pressure without complicated equipments. In this work, a protozoa, Tetrahymena thermophila (T. thermophila) SB210, was used to in vivo synthesize nano-selenium. The biosynthesized nano-selenium was characterized using transmission electron microscopy, energy dispersive X-ray spectroscopy and Raman spectroscopy. The synthesized amorphous spherical selenium nanoparticles had diameters of 50-500nm with the coexistence of irregular nano-selenium. The expressions of glutathione (GSH) synthesis related gene glutathione synthase, cysteine-rich protein metallothionein related gene metallothionein-1 and [2Fe-2S] cluster-binding protein related gene were up-regulated in the nano-selenium producing group. Also, the subsequent GSH detection and in vitro synthesis experimental results suggest the three proteins were likely to be involved in the nano-selenium synthesis process. Copyright © 2016 Elsevier Inc. All rights reserved.

Developments in Hollow Graphite Fiber Technology

NASA Technical Reports Server (NTRS)

Stallcup, Michael; Brantley, Lott W., Jr. (Technical Monitor)

2002-01-01

Hollow graphite fibers will be lighter than standard solid graphite fibers and, thus, will save weight in optical components. This program will optimize the processing and properties of hollow carbon fibers developed by MER and to scale-up the processing to produce sufficient fiber for fabricating a large ultra-lightweight mirror for delivery to NASA.

Fabrication of Fiber Optic Grating Apparatus and Method

NASA Technical Reports Server (NTRS)

Wang, Ying (Inventor); Sharma, Anup (Inventor); Grant, Joseph (Inventor)

2005-01-01

An apparatus and method for forming a Bragg grating on an optical fiber using a phase mask to diffract a beam of coherent energy and a lens combined with a pair of mirrors to produce two symmetrical virtual point sources of coherent energy in the plane of the optical fiber. The two virtual light sources produce an interference pattern along the optical fiber. In a further embodiment, the period of the pattern and therefore the Bragg wavelength grating applied to the fiber is varied with the position of the optical fiber relative the lens.

Interlaminar and ductile characteristics of carbon fibers-reinforced plastics produced by nanoscaled electroless nickel plating on carbon fiber surfaces.

PubMed

Park, Soo-Jin; Jang, Yu-Sin; Rhee, Kyong-Yop

2002-01-15

In this work, a new method based on nanoscaled Ni-P alloy coating on carbon fiber surfaces is proposed for the improvement of interfacial properties between fibers and epoxy matrix in a composite system. Fiber surfaces and the mechanical interfacial properties of composites were characterized by atomic absorption spectrophotometer (AAS), scanning electron microscopy (SEM), X-ray photoelectron spectrometry (XPS), interlaminar shear strength (ILSS), and impact strength. Experimental results showed that the O(1s)/C(1s) ratio or Ni and P amounts had been increased as the electroless nickel plating proceeded; the ILSS had also been slightly improved. The impact properties were significantly improved in the presence of Ni-P alloy on carbon fiber surfaces, increasing the ductility of the composites. This was probably due to the effect of substituted Ni-P alloy, leading to an increase of the resistance to the deformation and the crack initiation of the epoxy system.

Fiber optics structural mechanics and nanotechnology based new generation of fiber coatings

NASA Astrophysics Data System (ADS)

Suhir, E.

2006-02-01

This paper consists of two parts - review and extension. The review part deals with typical fiber optics structures (bare, single- and dual-coated fibers; fibers experiencing low temperature micro-bending; fibers soldered into ferrules or adhesively bonded into capillaries; role of the non-linear stress-strain relationship, etc.) subjected to thermally induced and/or mechanical loading in bending, tension, compression, or to various combinations of such loadings. The emphasis is on the state-of-the-art in the area of optical fiber coatings and the functional (optical), mechanical and environmental problems that occur in polymer-coated or metallized fibers. The solutions to the examined problems are obtained using analytical methods (predictive models) of structural mechanics. The review is based primarily on the author's research conducted at Bell Laboratories, Murray Hill, NJ, during his eighteen years tenure with this company. The extension part addresses a new generation of optical fiber coatings and deals with the application of a newly developed (by the ERS/Siloptix Co.) nano-particle material (NPM) that is used as an attractive substitute for the existing optical fiber coatings. This NPM-based coating has all the merits of polymer and metal coatings, but is free of their shortcomings. The developed material is an unconventional inhomogeneous "smart" composite material, which is equivalent to a homogeneous material with the following major properties: low Young's modulus, immunity to corrosion, good-to-excellent adhesion to adjacent material(s), non-volatile, stable properties at temperature extremes (from -220°C to +350°C), very long (practically infinite) lifetime, "active" hydrophobicity - the material provides a moisture barrier (to both water and water vapor), and, if necessary, can even "wick" moisture away from the contact surface; ability for "self-healing" and "healing": the NPM is able to restore its own dimensions, when damaged, and is able to

Low cost carbon fiber technology development for carbon fiber composite applications : phase 1.

DOT National Transportation Integrated Search

2008-01-01

The main goals of this research program at UTSI were: 1) to produce low cost carbon fibers and 2) to develop specific carbonbased : material technologies to meet current and future high performance fiber-reinforced composite needs of FTA and other : ...

Coatings for graphite fibers

NASA Technical Reports Server (NTRS)

Galasso, F. S.; Scola, D. A.; Veltri, R. D.

1980-01-01

Graphite fibers released from composites during burning or an explosion caused shorting of electrical and electronic equipment. Silicon carbide, silica, silicon nitride and boron nitride were coated on graphite fibers to increase their electrical resistances. Resistances as high as three orders of magnitude higher than uncoated fiber were attained without any significant degradation of the substrate fiber. An organo-silicone approach to produce coated fibers with high electrical resistance was also used. Celion 6000 graphite fibers were coated with an organo-silicone compound, followed by hydrolysis and pyrolysis of the coating to a silica-like material. The shear and flexural strengths of composites made from high electrically resistant fibers were considerably lower than the shear and flexural strengths of composites made from the lower electrically resistant fibers. The lower shear strengths of the composites indicated that the coatings on these fibers were weaker than the coating on the fibers which were pyrolyzed at higher temperature.

Thermoplastic coating of carbon fibers

NASA Technical Reports Server (NTRS)

Edie, D. D.; Lickfield, G. C.; Drews, M. J.; Ellison, M. S.; Gantt, B. W.

1989-01-01

A process is being developed which evenly coats individual carbon fibers with thermoplastic polymers. In this novel, continuous coating process, the fiber tow bundle is first spread cover a series of convex rollers and then evenly coated with a fine powder of thermoplastic matrix polymer. Next, the fiber is heated internally by passing direct current through the powder coated fiber. The direct current is controlled to allow the carbon fiber temperature to slightly exceed the flow temperature of the matrix polymer. Analysis of the thermoplastic coated carbon fiber tows produced using this continuous process indicates that 30 to 70 vol pct fiber prepregs can be obtained.

Design of nano- and microfiber combined scaffolds by electrospinning of collagen onto starch-based fiber meshes: a man-made equivalent of natural extracellular matrix.

PubMed

Tuzlakoglu, Kadriye; Santos, Marina I; Neves, Nuno; Reis, Rui L

2011-02-01

Mimicking the structural organization and biologic function of natural extracellular matrix has been one of the main goals of tissue engineering. Nevertheless, the majority of scaffolding materials for bone regeneration highlights biochemical functionality in detriment of mechanical properties. In this work we present a rather innovative construct that combines in the same structure electrospun type I collagen nanofibers with starch-based microfibers. These combined structures were obtained by a two-step methodology and structurally consist in a type I collagen nano-network incorporated on a macro starch-based support. The morphology of the developed structures was assessed by several microscopy techniques and the collagenous nature of the nano-network was confirmed by immunohistochemistry. In addition, and especially regarding the requirements of large bone defects, we also successfully introduced the concept of layer by layer, as a way to produce thicker structures. In an attempt to recreate bone microenvironment, the design and biochemical composition of the combined structures also envisioned bone-forming cells and endothelial cells (ECs). The inclusion of a type I collagen nano-network induced a stretched morphology and improved the metabolic activity of osteoblasts. Regarding ECs, the presence of type I collagen on the combined structures provided adhesive support and obviated the need of precoating with fibronectin. It was also importantly observed that ECs on the nano-network organized into circular structures, a three-dimensional arrangement distinct from that observed for osteoblasts and resembling the microcappillary-like organizations formed during angiogenesis. By providing simultaneously physical and chemical cues for cells, the herein-proposed combined structures hold a great potential in bone regeneration as a man-made equivalent of extracellular matrix.

Synthetic vitreous fibers--inhalation studies.

PubMed

McConnell, E E

1994-12-01

Synthetic vitreous fibers (SVFs), often referred to as "man-made vitreous fibers," are a class of materials that have their major uses for insulation against heat and sound. The original fibers are produced by melting various types of rock, clay, etc. and then blowing or extruding them into fibers of particular properties. During production and use small fractions of airborne fibers can be generated. Because of this a series of state-of-the-art inhalation studies was initiated to study the possible health hazards presented by the four major types of vitreous materials [two types of insulation glass wool, rock wool, slag wool, and four types of refractory ceramic fibers (RCF)] found in the workplace or to which the general public may be exposed. Rats and hamsters (30 mg/m3 kaolin-based RCF only) were exposed by nose-only inhalation to 3, 16, or 30 mg/m3 for 6 hr/day, 5 days/week, for 18 (hamsters) or 24 (rats) months and were held for lifetime observation (until approximately 20% survival) to study the chronic toxicity and potential carcinogenic activity of these classes of SVFs. Chrysotile or crocidolite asbestos served as positive controls. All of the fibers stimulated an inflammatory response characterized by an increase in the number of pulmonary macrophages at the level of the terminal bronchioles and proximal alveoli. RCF produced interstitial fibrosis in the walls of the proximal alveoli as early as 3 months and rock wool by 12 months. The only fiber which showed carcinogenic activity was RCF which produced a dose-related increase in both primary lung neoplasms (rats only) and mesotheliomas (rats and hamsters).

FTIR spectroscopy as a tool for nano-material characterization

NASA Astrophysics Data System (ADS)

Baudot, Charles; Tan, Cher Ming; Kong, Jeng Chien

2010-11-01

Covalently grafting functional molecules to carbon nanotubes (CNTs) is an important step to leverage the excellent properties of that nano-fiber in order to exploit its potential in improving the mechanical and thermal properties of a composite material. While Fourier Transform Infra Red (FTIR) spectroscopy can display the various chemical bonding in a material, we found that the existing database in FTIR library does not cover all the bonding information present in functionalized CNTs because the bond between the grafted molecule and the CNT is new in the FTIR study. In order to extend the applicability of FTIR to nano-material, we present a theoretical method to derive FTIR spectroscopy and compare it with our experimental results. In particular, we illustrate a method for the identification of functional molecules grafted on CNTs, and we are able to confirm that the functional molecules are indeed covalently grafted on the CNTs without any alterations to its functional groups.

Effects of Energetic and Inert Nano Particles on Burning Liquid Ethanol Droplets

NASA Astrophysics Data System (ADS)

Plascencia, Miguel; Sim, Hyung Sub; Vargas, Andres; Smith, Owen; Karagozian, Ann

2017-11-01

This study explores the effects of nano particulate additives on ethanol fuel droplet combustion in a quiescent environment. Two different types of droplet combustion experiments were performed: one involving the classic single droplet suspended from a quartz fiber and the other involving a burning droplet that has continual fuel delivery via a quartz capillary. Two alternative nano particles were explored here to demonstrate the effect of energetic additives: reactive nano aluminum (nAl) and inert nano silicon dioxide (nSiO2), each with average diameter 80 nm. Simultaneous high speed visible and OH* chemiluminescence images were taken to determine burning rate constants (K) and to study flame and droplet characteristics with varying particulate concentrations. Particle/vapor ejections were seen in continuously fed droplet experiments, while rod-suspended burning droplets showed limited particle ejection. The nSiO2 -laden, rod-suspended droplets formed a porous, shell-like structure resembling the shape of a droplet at higher nSiO2 concentrations, in contrast to smaller residue structures for nAl-laden droplets. Changes in K depended on concentrations of nAl and nSiO2 as well as the method of droplet formation, and TEM images of particle residue revealed additional insights. Supported by AFOSR Grant FA9550-15-1-0339.

Tunable Fiber Bragg Grating Ring Lasers using Macro Fiber Composite Actuators

NASA Technical Reports Server (NTRS)

Geddis, Demetris L.; Allison, Sidney G.; Shams, Qamar A.

2006-01-01

The research reported herein includes the fabrication of a tunable optical fiber Bragg grating (FBG) fiber ring laser (FRL)1 from commercially available components as a high-speed alternative tunable laser source for NASA Langley s optical frequency domain reflectometer (OFDR) interrogator, which reads low reflectivity FBG sensors. A Macro-Fiber Composite (MFC) actuator invented at NASA Langley Research Center (LaRC) was selected to tune the laser. MFC actuators use a piezoelectric sheet cut into uniaxially aligned rectangular piezo-fibers surrounded by a polymer matrix and incorporate interdigitated electrodes to deliver electric fields along the length of the piezo-fibers. This configuration enables MFC actuators to produce displacements larger than the original uncut piezoelectric sheet. The FBG filter was sandwiched between two MFC actuators, and when strained, produced approximately 3.62 nm of wavelength shift in the FRL when biasing the MFC actuators from 500 V to 2000 V. This tunability range is comparable to that of other tunable lasers and is adequate for interrogating FBG sensors using OFDR technology. Three different FRL configurations were studied. Configuration A examined the importance of erbium-doped fiber length and output coupling. Configuration B demonstrated the importance of the FBG filter. Configuration C added an output coupler to increase the output power and to isolate the filter. Only configuration C was tuned because it offered the best optical power output of the three configurations. Use of Plastic Optical Fiber (POF) FBG s holds promise for enhanced tunability in future research.

Two octaves spanning supercontinuum in highly nonlinear As2Se3 nanophotonic crystal fiber for midinfrared applications

NASA Astrophysics Data System (ADS)

Baili, Amira; Cherif, Rim; Zghal, Mourad

2015-01-01

A new design of all-normal and near-zero flattened dispersion based on chalcogenide nanophotonic crystal fiber (PCF) has been proposed to generate smooth and ultra-broadband supercontinuum (SC) in the midinfrared (IR) region. With the optimized geometric parameters, the As2Se3 nano-PCF has been found to be suitable for two-octave supercontinuum generation (SCG). We designed a nano-PCF having a flat top dispersion curve with a maximum value of -2.3 [ps/(nm km)] and a large nonlinear coefficient equal to 7250 W around the wavelength of 5.24 μm. By numerical simulations, we predict the generation of a very broadband SC in the mid-IR region extending from 2 to 10 μm in only 2-mm fiber lengths by using a femtosecond laser having a full-width at half-maximum of 50 fs and a relatively low energy of E=80 pJ. The generated SC demonstrates perfect coherence property over the entire bandwidth. SC generation extended into the mid-IR spectral region has potential usefulness in a variety of applications requiring a broad and mid-IR spectrum, such as WDM sources, fiber sensing, IR spectroscopy, fiber laser, and optical tomography coherence.

Distribution of polarization-entangled photonpairs produced via spontaneous parametric down-conversion within a local-area fiber network: theoretical model and experiment.

PubMed

Lim, Han Chuen; Yoshizawa, Akio; Tsuchida, Hidemi; Kikuchi, Kazuro

2008-09-15

We present a theoretical model for the distribution of polarization-entangled photon-pairs produced via spontaneous parametric down-conversion within a local-area fiber network. This model allows an entanglement distributor who plays the role of a service provider to determine the photon-pair generation rate giving highest two-photon interference fringe visibility for any pair of users, when given user-specific parameters. Usefulness of this model is illustrated in an example and confirmed in an experiment, where polarization-entangled photon-pairs are distributed over 82 km and 132 km of dispersion-managed optical fiber. Experimentally observed visibilities and entanglement fidelities are in good agreement with theoretically predicted values.

Direct writing of fiber optic components in photonic crystal fibers and other specialty fibers

NASA Astrophysics Data System (ADS)

Fernandes, Luis Andre; Sezerman, Omur; Best, Garland; Ng, Mi Li; Kane, Saidou

2016-04-01

Femtosecond direct laser writing has recently shown great potential for the fabrication of complex integrated devices in the cladding of optical fibers. Such devices have the advantage of requiring no bulk optical components and no breaks in the fiber path, thus reducing the need for complicated alignment, eliminating contamination, and increasing stability. This technology has already found applications using combinations of Bragg gratings, interferometers, and couplers for the fabrication of optical filters, sensors, and power monitors. The femtosecond laser writing method produces a local modification of refractive index through non-linear absorption of the ultrafast laser pulses inside the dielectric material of both the core and cladding of the fiber. However, fiber geometries that incorporate air or hollow structures, such as photonic crystal fibers (PCFs), still present a challenge since the index modification regions created by the writing process cannot be generated in the hollow regions of the fiber. In this work, the femtosecond laser method is used together with a pre-modification method that consists of partially collapsing the hollow holes using an electrical arc discharge. The partial collapse of the photonic band gap structure provides a path for femtosecond laser written waveguides to couple light from the core to the edge of the fiber for in-line power monitoring. This novel approach is expected to have applications in other specialty fibers such as suspended core fibers and can open the way for the integration of complex devices and facilitate miniaturization of optical circuits to take advantage of the particular characteristics of the PCFs.

Microstructure, hardness and modulus of carbon-ion-irradiated new SiC fiber (601-4)

NASA Astrophysics Data System (ADS)

Huang, Qing; Lei, Guanhong; Liu, Renduo; Li, Jianjian; Yan, Long; Li, Cheng; Liu, Weihua; Wang, Mouhua

2018-05-01

Two types of SiC fibers, one is low-oxygen and carbon-rich fiber denoted by 601-4 and the other is low-oxygen and near-stoichiometric Tyranno SA, were irradiated with 450 keV C+ ions at room temperature. The Raman spectra indicate that irradiation induced distortion and amorphization of SiC crystallites in fibers. TEM characterization of Tyranno SA suggests that SiC crystallites undergo a continued fragmentation into smaller crystalline islands and a continued increase of surrounding amorphous structure. The SiC nano-crystallites (<15 nm) in 601-4 fiber are more likely to be amorphized than larger crystallites (∼200 nm) in Tyranno SA. The hardness and modulus of 601-4 continuously decreases with increasing fluence, while that of Tyranno SA first increases and then decreases.

Graphene Nano-Composites for Hypervelocity Impact Applications

NASA Astrophysics Data System (ADS)

Manasrah, Alharith

The Low Earth Orbit (LEO) is a harsh environment cluttered with natural meteoroids and man-made debris, which can travel at velocities approaching 15 km/s. Most space activities within the LEO will encounter this environment. Thus, the spacecraft and its hardware must be designed to survive debris impact. This research introduces new procedures to produce a nano-composite material with mortar-brick nano-structure inspired from nacre. Nacre-like composites were successfully manufactured, based on three host polymers, with a wide range of graphene concentrations. The manufactured exfoliated graphene nano-platelet, embedded in a host polymer, provided good potential for enhancement of the hypervelocity impact (HVI) shield resistance. The nano-composites are suggested for use as a coating. Moreover, explicit dynamic finite element studies were conducted for further investigation of the hypervelocity impact of the graphene-based coatings in order to understand the effect of the coating on the crater formation and the exit velocity. This dissertation presents the results of the characterization and numerical sensitivity study of the developed material parameters. The numerical simulations were performed by implementing Autodyn smooth particle hydrodynamics. This study provides innovative, low-weight shielding enhancements for spacecraft, as well as other promising applications for the manufactured nano-composites.

Exposure to nanoscale particles and fibers during machining of hybrid advanced composites containing carbon nanotubes

NASA Astrophysics Data System (ADS)

Bello, Dhimiter; Wardle, Brian L.; Yamamoto, Namiko; Guzman deVilloria, Roberto; Garcia, Enrique J.; Hart, Anastasios J.; Ahn, Kwangseog; Ellenbecker, Michael J.; Hallock, Marilyn

2009-01-01

This study investigated airborne exposures to nanoscale particles and fibers generated during dry and wet abrasive machining of two three-phase advanced composite systems containing carbon nanotubes (CNTs), micron-diameter continuous fibers (carbon or alumina), and thermoset polymer matrices. Exposures were evaluated with a suite of complementary instruments, including real-time particle number concentration and size distribution (0.005-20 μm), electron microscopy, and integrated sampling for fibers and respirable particulate at the source and breathing zone of the operator. Wet cutting, the usual procedure for such composites, did not produce exposures significantly different than background whereas dry cutting, without any emissions controls, provided a worst-case exposure and this article focuses here. Overall particle release levels, peaks in the size distribution of the particles, and surface area of released particles (including size distribution) were not significantly different for composites with and without CNTs. The majority of released particle surface area originated from the respirable (1-10 μm) fraction, whereas the nano fraction contributed 10% of the surface area. CNTs, either individual or in bundles, were not observed in extensive electron microscopy of collected samples. The mean number concentration of peaks for dry cutting was composite dependent and varied over an order of magnitude with highest values for thicker laminates at the source being >1 × 106 particles cm-3. Concentration of respirable fibers for dry cutting at the source ranged from 2 to 4 fibers cm-3 depending on the composite type. Further investigation is required and underway to determine the effects of various exposure determinants, such as specimen and tool geometry, on particle release and effectiveness of controls.

Thermal characteristics of carbon fiber reinforced epoxy containing multi-walled carbon nanotubes

NASA Astrophysics Data System (ADS)

Lee, Jin-woo; Park, Soo-Jeong; Kim, Yun-hae; Riichi-Murakami

2018-06-01

The material with irregular atomic structures such as polymer material exhibits low thermal conductivity because of the complex structural properties. Even materials with same atomic configurations, thermal conductivity may be different based on their structural properties. It is expected that nanoparticles with conductivity will change non-conductive polymer base materials to electrical conductors, and improve the thermal conductivity even with extremely small filling amount. Nano-composite materials contain nanoparticles with a higher surface ratio which makes the higher interface percentage to the total surface of nanoparticles. Therefore, thermal resistance of the interface becomes a dominating factor determines the effective thermal conductivity in nano-composite materials. Carbon fiber has characteristic of resistance or magnetic induction and Also, Carbon nanotube (CNT) has electronic and thermal property. It can be applied for heating system. These characteristic are used as heating composite. In this research, the exothermic characteristics of Carbon fiber reinforced composite added CNT were evaluated depend on CNT length and particle size. It was found that the CNT dispersed in the resin reduces the resistance between the interfaces due to the decrease in the total resistance of the heating element due to the addition of CNTs. It is expected to improve the life and performance of the carbon fiber composite material as a result of the heating element resulting from this paper.

Synergism of Electrospinning and Nano-alumina Trihydrate on the Polymorphism, Crystallinity and Piezoelectric Performance of PVDF Nanofibers

NASA Astrophysics Data System (ADS)

Khalifa, Mohammed; Deeksha, B.; Mahendran, Arunjunairaj; Anandhan, S.

2018-03-01

Poly(vinlylidene fluoride) (PVDF) is known for its electroactive phases, which can be nucleated by incorporating nanoparticles into PVDF to enhance its piezoelectric performance. In this study, the synergistic effect of electrospinning and nano alumina trihydrate (ATH) filler was used to enhance the electroactive β phase of PVDF. Electrospun nanofibers of PVDF/ATH nanocomposite (PANCF) were synthesized with different loadings of ATH. The presence of ATH enhances the surface charges of the electrospun droplets, leading to thinner fibers. The highest β-phase content was found to be 70.1% for PANCF with 10% ATH. The piezoelectric performance of the nanofiber mats was studied using an indigenous setup. The highest voltage output of 840 mV was produced by PANCF with 10% ATH. These nanofibers could be a promising material in the field of sensors, actuators and energy-harvesting applications.

Optical Fibers Would Sense Local Strains

NASA Technical Reports Server (NTRS)

Egalon, Claudio O.; Rogowski, Robert S.

1994-01-01

Proposed fiber-optic transducers measure local strains. Includes lead-in and lead-out lengths producing no changes in phase shifts, plus short sensing length in which phase shift is sensitive to strain. Phase shifts in single-mode fibers vary with strains. In alternative version, multiple portions of optical fiber sensitive to strains characteristic of specific vibrational mode of object. Same principle also used with two-mode fiber.

Anodization: a promising nano-modification technique of titanium implants for orthopedic applications.

PubMed

Yao, Chang; Webster, Thomas J

2006-01-01

Anodization is a well-established surface modification technique that produces protective oxide layers on valve metals such as titanium. Many studies have used anodization to produce micro-porous titanium oxide films on implant surfaces for orthopedic applications. An additional hydrothermal treatment has also been used in conjunction with anodization to deposit hydroxyapatite on titanium surfaces; this is in contrast to using traditional plasma spray deposition techniques. Recently, the ability to create nanometer surface structures (e.g., nano-tubular) via anodization of titanium implants in fluorine solutions have intrigued investigators to fabricate nano-scale surface features that mimic the natural bone environment. This paper will present an overview of anodization techniques used to produce micro-porous titanium oxide structures and nano-tubular oxide structures, subsequent properties of these anodized titanium surfaces, and ultimately their in vitro as well as in vivo biological responses pertinent for orthopedic applications. Lastly, this review will emphasize why anodized titanium structures that have nanometer surface features enhance bone forming cell functions.

Ultrasonic-assisted synthesis of nano lead(II) coordination polymer as precursors for preparation of lead(II) oxide nano-structures: Thermal, optical properties and XRD studies.

PubMed

Ghavidelaghdam, Elham; Shahverdizadeh, Gholam Hossein; Motameni Tabatabai, Javad; Mirtamizdoust, Babak

2018-04-01

Nano structure of a lead (II) coordination polymer [Pb 2 (C 2 Cl 3 O 2 ) 2 (NO 3 ) 2 (C l2 H 8 N 2 ) 2 ] n (1), has been synthesized by a sonochemical method in different concentrations. The nano particles were characterized by scanning electron microscopy (SEM) X-ray powder diffraction (XRD), FT-IR spectroscopy and elemental analyses. The thermal stability of nano structure is closely investigated via thermal gravimetric (TGA), and compared with crystalline structure. The compounds are then heated to 600 °C to produce PbO nano particles. The resulting PbO is characterized through XRD and SEM analyses. Concentration of initial reagents effects on size and morphology of nano-structured compound 1 have been studied and show that low concentrations of initial reagents decreased particles size and leaded to uniform nano particles morphology. The photoluminescence properties of the prepared compound, as crystalline and as nanoparticles, have been investigated. The result showed a good correlation between the size and emission wavelength. Copyright © 2017. Published by Elsevier B.V.

Experimental results of antigliadin antibodies detection using long period fiber grating

NASA Astrophysics Data System (ADS)

Corres, J. M.; Matias, I. R.; Goicoechea, J.; Arregui, F. J.; Viegas, D.; Araújo, F. M.; Santos, J. L.

2008-04-01

In this work a new nano-biofilm is proposed for the detection of celiac disease (CD). A long-period fiber grating (LPFG) is used as a transducer and the surface of the fiber is coated with a precursor layer of SiO2-nanospheres using the electrostatic self-assembly technique (ESA). This layer has been designed in order to create a substrate of high porosity where the gliadins could be deposited. Under the presence of specific antibodies antigliadin antibodies (AGA) the refractive index of the overlay changes giving a detectable shift in the resonance wavelength of the LPFG. Concentrations as low as 5 ppm were detected.

Physical properties of a frozen yogurt fortified with a nano-emulsion containing purple rice bran oil

USDA-ARS?s Scientific Manuscript database

The objectives of this study were to develop and evaluate a frozen yogurt (FY) fortified with a nano-emulsion containing purple rice bran oil (NPRBO). A nano-emulsion with a droplet size range of 150-300 nm was produced by sonication followed by ultra-shear homogenization. The nano-emulsion was mi...

Development of a continuous spinning process for producing silicon carbide - silicon nitride precursor fibers

NASA Technical Reports Server (NTRS)

1985-01-01

An apparatus was designed for the continuous production of silicon carbide - silicon nitride precursor fibers. The precursor polymer can be fiberized, crosslined and pyrolyzed. The product is a metallic black fiber with the composition of the type C sub x Si sub y n sub z. Little, other than the tensile strength and modulus of elasticity, is known of the physical properties.

He bubble growth and interaction in W nano-tendrils

NASA Astrophysics Data System (ADS)

Smirnov, R. D.; Krasheninnikov, S. I.

2015-11-01

Tungsten plasma-facing components (PFCs) in fusion devices are exposed to variety of extreme plasma conditions, which can lead to alteration of tungsten micro-structure and degradation of the PFCs. In particular, it is known that filamentary nano-structures called fuzz can grow on helium plasma exposed tungsten surfaces. However, mechanism of the fuzz growth is still not fully understood. Existing experimental observations indicate that formation of helium nano-bubbles in tungsten plays essential role in fuzz formation and growth. In this work we investigate mechanisms of growth and interaction of helium bubbles in fuzz-like nano-tendrils using molecular dynamics simulations with LAMMPS code. We show that growth of the bubbles has anisotropic character producing complex stress field in the nano-tendrils with distinct compression and tension regions. We found that formation of large inter-bubble tension regions can cause lateral stretching and bending of the tendrils that consequently lead to their elongation and thinning at the stretching sites. The rate of nano-tendril growth due to the described mechanism is also evaluated from the simulations.

The effect of interlaminar graphene nano-sheets reinforced e-glass fiber/ epoxy on low velocity impact response of a composite plate

NASA Astrophysics Data System (ADS)

Al-Maharma, A. Y.; Sendur, P.

2018-05-01

In this study, we compare the inter-laminar effect of graphene nano-sheets (GNSs) and CNTs on the single and multiple dynamic impact response of E-glass fiber reinforced epoxy composite (GFEP). In the comparisons, raw GFEP composite is used as baseline for quantifying the improvement on the dynamic impact response. For that purpose, finite element based models are developed for GNSs on GFEP, graphene coating on glass fibers, inter-laminar composite of CNTs reinforced polyester at 7.5 vol%, and combinations of all these reinforcements. Comparisons are made on three metrics: (i) total deformation, (ii) the contact force, and (iii) internal energy of the composite plate. The improvement on axial modulus (E1) of GFEP reinforced with one layer of GNS (0.5 wt%) without polyester at lamination sequence of [0]8 is 29.4%, which is very close to the improvement of 31% on storage modulus for multi-layer graphene with 0.5 wt% reinforced E-glass/epoxy composite at room temperature. Using three GNSs (1.5 wt%) reinforced polyester composite as interlaminar layer results in an improvement of 57.1% on E1 of GFEP composite. The simulation results reveal that the interlaminar three GNSs/polyester composite at mid-plane of GFEP laminated composite can significantly improve the dynamic impact resistance of GFEP structure compared to the other aforementioned structural reinforcements. Reinforcing GFEP composite with three layers of GNSs/polyester composite at mid-plane results in an average of 35% improvement on the dynamic impact resistance for healthy and damaged composite plate under low velocity impacts of single and multiple steel projectiles. This model can find application in various areas including structural health monitoring, fire retardant composite, and manufacturing of high strength and lightweight mechanical parts such as gas tank, aircraft wings and wind turbine blades.

Fiber-optic liquid level sensor

DOEpatents

Weiss, Jonathan D.

1991-01-01

A fiber-optic liquid level sensor measures the height of a column of liquid through the hydrostatic pressure it produces. The sensor employs a fiber-optic displacement sensor to detect the pressure-induced displacement of the center of a corrugated diaphragm.

Tapered fiber coupling of single photons emitted by a deterministically positioned single nitrogen vacancy center

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liebermeister, Lars, E-mail: lars.liebermeister@physik.uni-muenchen.de; Petersen, Fabian; Münchow, Asmus v.

2014-01-20

A diamond nano-crystal hosting a single nitrogen vacancy (NV) center is optically selected with a confocal scanning microscope and positioned deterministically onto the subwavelength-diameter waist of a tapered optical fiber (TOF) with the help of an atomic force microscope. Based on this nano-manipulation technique, we experimentally demonstrate the evanescent coupling of single fluorescence photons emitted by a single NV-center to the guided mode of the TOF. By comparing photon count rates of the fiber-guided and the free-space modes and with the help of numerical finite-difference time domain simulations, we determine a lower and upper bound for the coupling efficiency ofmore » (9.5 ± 0.6)% and (10.4 ± 0.7)%, respectively. Our results are a promising starting point for future integration of single photon sources into photonic quantum networks and applications in quantum information science.« less

Photonic crystal fiber heat sensors

NASA Astrophysics Data System (ADS)

Twigg, S.; Coompson, J.; Colalillo, A.; Wynne, R.

2011-04-01

A sensing configuration based on commercially available triple-core photonic crystal fiber (PCF) for the image-based collection of thermal information is presented. Detection of thermal phenomena on the micro and nano scale is important for monitoring thermodynamic processes including cooling mechanisms for industry and basic research in both civil and mechanical systems. The thermal characteristics of the PCF combined with coupled-mode theory principles are used to construct a three core PCF with a 1-D core arrangement to simultaneously measure heat flux and temperature. The PCF sensor demonstrated high detection sensitivity (<1°C) and fast response times (<30μs), which is a significant improvement to current commercial standards. PCFs are specialty optical fibers that contain carefully spaced micronsized cavities that provide extraordinary waveguide characteristics not demonstrated by standard optical fiber. The three core PCF has a core diameter of 3.9μm, outer diameter of 132.5μm and varied inter core spacing. A single mode fiber is fusion spliced with the multi-core PCF such that the optical field is confined and launched into the PCF core. The output end of the fiber is inspected and imaged with a CCD camera. A 25mm section of the PCF is surrounded by a guarded hotplate configuration to control the thermal conditions for sensor characterization. Evanescent wave coupling occurs whereby power is transferred from the central core to a neighboring core. Minimum detection sensitivities of 0.2 °C were recorded. Theoretical sensitivities on the order of 10-2 °C are possible. Experimental results were in agreement with coupled-mode theoretical results.

Caging antimicrobial silver nanoparticles inside cotton

USDA-ARS?s Scientific Manuscript database

In this study, a stable, non-leaching Ag-cotton nanocomposite fiber has been characterized. Siver nanoparticles (Ag NPs) were previously synthesized in the alkali-swollen substructure of cotton fiber; the nano-sized micofibrillar channels allowed diffusion-controlled conditions to produce mono-dispe...

UV Polymerization of Hydrodynamically Shaped Fibers

DTIC Science & Technology

2011-01-01

using passive wall structures was used to shape a prepolymer stream, which was subsequently polymerized using UV exposure. The shape designed using flow...simulations was maintained, and the size of the fibers was controlled using the ratio of the flow rates of the sheath and the prepolymer . The fibers... prepolymer fluids. This microfluidic approach for production of fibers with defined cross-sectional shape can produce fibers for further development

Production process of a new cellulosic fiber with antimicrobial properties.

PubMed

Zikeli, Stefan

2006-01-01

The Lyocell process (system: cellulose-water-N-methylmorpholine oxide) of Zimmer AG offers special advantages for the production of cellulose fibers. The process excels by dissolving the most diverse cellulose types as these are optimally adjusted to the process by applying different pretreatment methods. Based on this stable process, Zimmer AG's objective is to impart to the Lyocell fiber additional value to improve quality of life and thus to tap new markets for the product. Thanks to the specific incorporation of seaweed, the process allows to produce cellulose Lyocell fibers with additional and new features. They are activated in a further step - by specific charging with metal ions - in order to obtain antibacterial properties. The favorable textile properties of fibers produced by the Lyocell process are not adversely affected by the incorporation of seaweed material or by activation to obtain an antibacterial fiber so that current textile products can be made from the fibers thus produced. The antibacterial effect is achieved by metal ion activation of the Lyocell fibers with incorporated seaweed, which contrasts with the antibacterial fibers known so far. Antibacterial fibers produced by conventional methods are in part only surface finished with antibacterially active chemicals or else they are produced by incorporating organic substances with antibacterial and fungicidal effects. Being made from cellulose, the antibacterial Lyocell fiber Sea Cell Active as the basis for quality textiles exhibits a special wear comfort compared to synthetic fibers with antibacterial properties and effects. This justifies the conclusion that the Zimmer Lyocell process provides genuine value added and that it is a springboard for further applications.

High-energy master oscillator power amplifier with near-diffraction-limited output based on ytterbium-doped PCF fiber

NASA Astrophysics Data System (ADS)

Li, Rao; Qiao, Zhi; Wang, Xiaochao; Fan, Wei; Lin, Zunqi

2017-10-01

With the development of fiber technologies, fiber lasers are able to deliver very high power beams and high energy pulses which can be used not only in scientific researches but industrial fields (laser marking, welding,…). The key of high power fiber laser is fiber amplifier. In this paper, we present a two-level master-oscillator power amplifier system at 1053 nm based on Yb-doped photonic crystal fibers. The system is used in the front-end of high power laser facility for the amplification of nano-second pulses to meet the high-level requirements. Thanks to the high gain of the system which is over 50 dB, the pulse of more than 0.89 mJ energy with the nearly diffraction-limited beam quality has been obtained.

Melamine sensing based on evanescent field enhanced optical fiber sensor

NASA Astrophysics Data System (ADS)

Luo, Ji; Yao, Jun; Wang, Wei-min; Zhuang, Xu-ye; Ma, Wen-ying; Lin, Qiao

2013-08-01

Melamine is an insalubrious chemical, and has been frequently added into milk products illegally, to make the products more protein-rich. However, it can cause some various diseases, such as kidney stones and bladder cancer. In this paper, a novel optical fiber sensor with high sensitivity based on absorption of the evanescent field for melamine detection is successfully proposed and developed. Different concentrations of melamine changing from 0 to 10mg/mL have been detected using the micro/nano-sensing fiber decorated with silver nanoparticles cluster layer. As the concentration increases, the sensing fiber's output intensity gradually deceases and the absorption of the analyte becomes large. The concentration changing of 1mg/ml can cause the absorbance varying 0.664 and the limit of the melamine detectable concentration is 1ug/mL. Besides, the coupling properties between silver nanoparticles have also been analyzed by the FDTD method. Overall, this evanescent field enhanced optical fiber sensor has potential to be used in oligo-analyte detection and will promote the development of biomolecular and chemical sensing applications.

Development of thermoelectric fibers for miniature thermoelectric devices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ren, Fei; Menchhofer, Paul A.; Kiggans, Jr., James O.

Miniature thermoelectric (TE) devices may be used in a variety of applications such as power sources of small sensors, temperature regulation of precision electronics, etc. Reducing the size of TE elements may also enable design of novel devices with unique form factor and higher device efficiency. Current industrial practice of fabricating TE devices usually involves mechanical removal processes that not only lead to material loss but also limit the geometry of the TE elements. In this project, we explored a powder-processing method for the fabrication of TE fibers with large length-to-area ratio, which could be potentially used for miniature TEmore » devices. Powders were milled from Bi2Te3-based bulk materials and then mixed with a thermoplastic resin dissolved in an organic solvent. Through an extrusion process, flexible, continuous fibers with sub-millimeter diameters were formed. The polymer phase was then removed by sintering. Sintered fibers exhibited similar Seebeck coefficients to the bulk materials. Moreover, their electrical resistivity was much higher, which might be related to the residual porosity and grain boundary contamination. Prototype miniature uni-couples fabricated from these fibers showed a linear I-V behavior and could generate millivolt voltages and output power in the nano-watt range. Further development of these TE fibers requires improvement in their electrical conductivities, which needs a better understanding of the causes that lead to the low conductivity in the sintered fibers.« less

Development of thermoelectric fibers for miniature thermoelectric devices

DOE PAGES

Ren, Fei; Menchhofer, Paul A.; Kiggans, Jr., James O.; ...

2016-09-23

Miniature thermoelectric (TE) devices may be used in a variety of applications such as power sources of small sensors, temperature regulation of precision electronics, etc. Reducing the size of TE elements may also enable design of novel devices with unique form factor and higher device efficiency. Current industrial practice of fabricating TE devices usually involves mechanical removal processes that not only lead to material loss but also limit the geometry of the TE elements. In this project, we explored a powder-processing method for the fabrication of TE fibers with large length-to-area ratio, which could be potentially used for miniature TEmore » devices. Powders were milled from Bi2Te3-based bulk materials and then mixed with a thermoplastic resin dissolved in an organic solvent. Through an extrusion process, flexible, continuous fibers with sub-millimeter diameters were formed. The polymer phase was then removed by sintering. Sintered fibers exhibited similar Seebeck coefficients to the bulk materials. Moreover, their electrical resistivity was much higher, which might be related to the residual porosity and grain boundary contamination. Prototype miniature uni-couples fabricated from these fibers showed a linear I-V behavior and could generate millivolt voltages and output power in the nano-watt range. Further development of these TE fibers requires improvement in their electrical conductivities, which needs a better understanding of the causes that lead to the low conductivity in the sintered fibers.« less

Biobased Nano Porous Active Carbon Fibers for High-Performance Supercapacitors.

PubMed

Huang, Yuxiang; Peng, Lele; Liu, Yue; Zhao, Guangjie; Chen, Jonathan Y; Yu, Guihua

2016-06-22

Activated carbon fibers (ACFs) with different pore structure have been prepared from wood sawdust using the KOH activation method. A study was conducted to examine the influence of the activation parameters (temperature, alkali/carbon ratio, and time) on the morphology and structure of the as-prepared ACFs developed in the process of pore generation and evolution. Activation temperature was very essential for the formation of utramicropores (<0.6 nm), which greatly contributed to the electric double layer capacitance. The significance of metallic potassium vapor evolved when the temperature was above 800 °C, since the generation of 0.8- and 1.1 nm micropores cannot be ignored. When the the KOH/fiber ratio was increased and the activation time was prolonged, to some extent, the micropores were enlarged to small mesopores within 2-5 nm. The sample with the optimal condition exhibited the highest specific capacitance (225 F g(-1) at a current density of 0.5 A g(-1)). Its ability to retain capacitance corresponding to 10 A g(-1) and 6 M KOH was 85.3%, demonstrating a good rate capability. With 10 000 charge-discharge cycles at 3 A g(-1), the supercapacitor kept 94.2% capacity, showing outstanding electrochemical performance as promising electrode material.

Fiber bundle phase conjugate mirror

DOEpatents

Ward, Benjamin G.

2012-05-01

An improved method and apparatus for passively conjugating the phases of a distorted wavefronts resulting from optical phase mismatch between elements of a fiber laser array are disclosed. A method for passively conjugating a distorted wavefront comprises the steps of: multiplexing a plurality of probe fibers and a bundle pump fiber in a fiber bundle array; passing the multiplexed output from the fiber bundle array through a collimating lens and into one portion of a non-linear medium; passing the output from a pump collection fiber through a focusing lens and into another portion of the non-linear medium so that the output from the pump collection fiber mixes with the multiplexed output from the fiber bundle; adjusting one or more degrees of freedom of one or more of the fiber bundle array, the collimating lens, the focusing lens, the non-linear medium, or the pump collection fiber to produce a standing wave in the non-linear medium.

Molecular interactions in self-assembled nano-structures of chitosan-sodium alginate based polyelectrolyte complexes.

PubMed

Wasupalli, Geeta Kumari; Verma, Devendra

2018-03-16

We report here the self-assembled structures of polyelectrolyte complexes (PECs) of polyanionic sodium alginate with the polycationic chitosan at room temperature. The PECs prepared at different pH values exhibited two distinct morphologies. The chitosan-alginate PECs self-assembled into the fibrous structure in a low pH range of pH3 to 7. The PECs obtained at high pH series around pH8 and above resulted in the formation of colloidal nanoparticles in the range of 120±9.48nm to 46.02±16.66nm. The zeta potential measurement showed that PECs prepared at lower pH (pH<6) exhibited nearly neutral surface charge, whereas PECs prepared at higher pH than 6 exhibited highly negative surface charge. The molecular interactions in nano-colloids and fibers were evaluated using FTIR analysis. The results attest that the ionic state of the chitosan and alginate plays an important role controlling the morphologies of the PECS. The present study has identified the enormous potential of the polyelectrolytes complexes to exploit shape by the alteration of ionic strength. These findings might be useful in the development of novel biomaterial. The produced fibers and nanocolloids could be applied as a biomaterial for tissue engineering and drug delivery. Copyright © 2017. Published by Elsevier B.V.

Environmental risk assessment of engineered nano-SiO2 , nano iron oxides, nano-CeO2 , nano-Al2 O3 , and quantum dots.

PubMed

Wang, Yan; Nowack, Bernd

2018-05-01

Many research studies have endeavored to investigate the ecotoxicological hazards of engineered nanomaterials (ENMs). However, little is known regarding the actual environmental risks of ENMs, combining both hazard and exposure data. The aim of the present study was to quantify the environmental risks for nano-Al 2 O 3 , nano-SiO 2 , nano iron oxides, nano-CeO 2 , and quantum dots by comparing the predicted environmental concentrations (PECs) with the predicted-no-effect concentrations (PNECs). The PEC values of these 5 ENMs in freshwaters in 2020 for northern Europe and southeastern Europe were taken from a published dynamic probabilistic material flow analysis model. The PNEC values were calculated using probabilistic species sensitivity distribution (SSD). The order of the PNEC values was quantum dots < nano-CeO 2  < nano iron oxides < nano-Al 2 O 3  < nano-SiO 2 . The risks posed by these 5 ENMs were demonstrated to be in the reverse order: nano-Al 2 O 3  > nano-SiO 2  > nano iron oxides > nano-CeO 2  > quantum dots. However, all risk characterization values are 4 to 8 orders of magnitude lower than 1, and no risk was therefore predicted for any of the investigated ENMs at the estimated release level in 2020. Compared to static models, the dynamic material flow model allowed us to use PEC values based on a more complex parameterization, considering a dynamic input over time and time-dependent release of ENMs. The probabilistic SSD approach makes it possible to include all available data to estimate hazards of ENMs by considering the whole range of variability between studies and material types. The risk-assessment approach is therefore able to handle the uncertainty and variability associated with the collected data. The results of the present study provide a scientific foundation for risk-based regulatory decisions of the investigated ENMs. Environ Toxicol Chem 2018;37:1387-1395. © 2018 SETAC. © 2018 SETAC.

Mid-infrared supercontinuum generation in As2S3-silica "nano-spike" step-index waveguide.

PubMed

Granzow, N; Schmidt, M A; Chang, W; Wang, L; Coulombier, Q; Troles, J; Toupin, P; Hartl, I; Lee, K F; Fermann, M E; Wondraczek, L; Russell, P St J

2013-05-06

Efficient generation of a broad-band mid-infrared supercontinuum spectrum is reported in an arsenic trisulphide waveguide embedded in silica. A chalcogenide "nano-spike", designed to transform the incident light adiabatically into the fundamental mode of a 2-mm-long uniform section 1 µm in diameter, is used to achieve high launch efficiencies. The nano-spike is fully encapsulated in a fused silica cladding, protecting it from the environment. Nano-spikes provide a convenient means of launching light into sub-wavelength scale waveguides. Ultrashort (65 fs, repetition rate 100 MHz) pulses at wavelength 2 µm, delivered from a Tm-doped fiber laser, are launched with an efficiency ~12% into the sub-wavelength chalcogenide waveguide. Soliton fission and dispersive wave generation along the uniform section result in spectral broadening out to almost 4 µm for launched energies of only 18 pJ. The spectrum generated will have immediate uses in metrology and infrared spectroscopy.

Recent advancements in transparent ceramics and crystal fibers for high power lasers

NASA Astrophysics Data System (ADS)

Kim, W.; Baker, C.; Villalobos, G.; Florea, C.; Gibson, D.; Shaw, L. B.; Bowman, S.; Bayya, S.; Sadowski, B.; Hunt, M.; Askins, C.; Peele, J.; Aggarwal, I. D.; Sanghera, J. S.

2013-05-01

In this paper, we present our recent progress in the development of rare-earth (Yb3+ or Ho3+) doped Lu2O3 and Y2O3 sesquioxides for high power solid state lasers. We have fabricated high quality transparent ceramics using nano-powders synthesized by a co-precipitation method. This was accomplished by developments in high purity powder synthesis and low temperature scalable sintering technology developed at NRL. The optical, spectral and morphological properties as well as the lasing performance from our highly transparent ceramics are presented. In the second part of the paper, we discuss our recent research effort in developing cladded-single crystal fibers for high power single frequency fiber lasers has the potential to significantly exceed the capabilities of existing silica fiber based lasers. Single crystal fiber cores with diameters as small as 35μm have been drawn using high purity rare earth doped ceramic or single crystal feed rods by the Laser Heated Pedestal Growth (LHPG) process. Our recent results on the development of suitable claddings on the crystal fiber core are discussed.

A differential detection scheme of spectral shifts in long-period fiber gratings

NASA Astrophysics Data System (ADS)

Zhelyazkova, Katerina; Eftimov, Tinko; Smietana, Mateusz; Bock, Wojtek

2010-10-01

In this work we present an analysis of the response of a compact, simple and inexpensive optoelectronic sensor system intended to detect spectral shifts of a long-period fiber grating (LPG). The system makes use of a diffraction grating and a couple of receiving optical fibers that pick up signals at two different wavelengths. This differential detection system provides the same useful information from an LPG-based sensor as with a conventional laboratory system using optical spectrum analyzers for monitoring the minimum offset of LPG. The design of the fiber detection pair as a function of the parameters of the dispersion grating, the pick-up fiber and the LPG parameters, is presented in detail. Simulation of the detection system responses is presented using real from spectral shifts in nano-coated LPGs caused by the evaporation of various liquids such as water, ethanol and acetone, which are examples of corrosive, flammable and hazardous substances. Fiber optic sensors with similar detection can find applications in structural health monitoring for moisture detection, monitoring the spillage of toxic and flammable substances in industry etc.

Omega-3 PUFA concentration by a novel PVDF nano-composite membrane filled with nano-porous silica particles.

PubMed

Ghasemian, Samaneh; Sahari, Mohammad Ali; Barzegar, Mohsen; Ahmadi Gavlighi, Hasan

2017-09-01

In this study, polyvinylidene fluoride (PVDF) and nano-porous silica particle were used to fabricate an asymmetric nano-composite membrane. Silica particles enhanced the thermal stability of PVDF/SiO 2 membranes; increasing the decomposition temperature from 371°C to 408°C. Cross sectional morphology showed that silica particles were dispersed in polymer matrix uniformly. However, particle agglomeration was found at higher loading of silica (i.e., 20 by weight%). The separation performance of nano-composite membranes was also evaluated using the omega-3 polyunsaturated fatty acids (PUFA) concentration at a temperature and pressure of 30°C and 4bar, respectively. Silica particle increased the omega-3PUFA concentration from 34.8 by weight% in neat PVDF to 53.9 by weight% in PVDF with 15 by weight% of silica. Moreover, PVDF/SiO 2 nano-composite membranes exhibited enhanced anti-fouling property compared to neat PVDF membrane. Fouling mechanism analysis revealed that complete pore blocking was the predominant mechanism occurring in oil filtration. The concentration of omega-3 polyunsaturated fatty acids (PUFA) is important in the oil industries. While the current methods demand high energy consumptions in concentrating the omega-3, membrane separation technology offers noticeable advantages in producing pure omega-3 PUFA. Moreover, concentrating omega-3 via membrane separation produces products in the triacylglycerol form which possess better oxidative stability. In this work, the detailed mechanisms of fouling which limits the performance of membrane separation were investigated. Incorporating silica particles to polymeric membrane resulted in the formation of mixed matrix membrane with improved anti-fouling behaviour compared to the neat polymeric membrane. Hence, the industrial potential of membrane processing to concentrate omega-3 fatty acids is enhanced. Copyright © 2017. Published by Elsevier Ltd.

Fiber-coupled pillar array as a highly pure and stable single-photon source

NASA Astrophysics Data System (ADS)

Odashima, S.; Sasakura, H.; Nakajima, H.; Kumano, H.

2017-12-01

A highly pure and stable single-photon source is prepared that comprises a well-designed pillar array, in which each pillar contains only a few InAs quantum dots. A nano-pillar in this array is in direct contact with a fiber end surface and cooled in a liquid-He bath. Auto-correlation measurements show that this source provides an average g(2)(0) value of 0.0174 in the measured excitation-power range. This photon source and fiber coupling are quite rigid against external disturbances such as cooling-heating cycles and vibration, with long-term stability.

Dual luciferase assay for secreted luciferases based on Gaussia and NanoLuc.

PubMed

Heise, Kerstin; Oppermann, Henry; Meixensberger, Jürgen; Gebhardt, Rolf; Gaunitz, Frank

2013-05-01

Just recently, NanoLuc, a new engineered luciferase based on the small subunit of the luciferase from Oplophorus gracilirostris was introduced. Like the luciferase from Gaussia princeps, this luciferase is secreted into the medium. Both luciferases are the smallest and brightest luciferases known and well-suited for reporter assays. In our experiments, we demonstrate that both luciferases can be used together in a dual-reporter assay by solving the problem that NanoLuc produces a significant signal with coelenterazine, which is the substrate for Gaussia luciferase. We found that the background signal from NanoLuc with coelenterazine can be calculated from the determination of NanoLuc activity in the presence of its substrate furimazine. This in turn allows the precise determination of the activity of Gaussia which does not produce light in the presence of furimazine. Based on this observation, we developed a high sensitive dual secreted luciferase assay which allows the determination of both activities in a single cotransfection experiment. We demonstrate the versatility and robustness of the assay for the normalization of reporter gene activities. Since Gaussia luciferase and NanoLuc are nonhomologous reporters, the method to determine both luciferase activities may also be useful for coincidence reporter gene systems for high-throughput screening.

Nano-Electrochemistry and Nano-Electrografting with an Original Combined AFM-SECM

PubMed Central

Ghorbal, Achraf; Grisotto, Federico; Charlier, Julienne; Palacin, Serge; Goyer, Cédric; Demaille, Christophe; Ben Brahim, Ammar

2013-01-01

This study demonstrates the advantages of the combination between atomic force microscopy and scanning electrochemical microscopy. The combined technique can perform nano-electrochemical measurements onto agarose surface and nano-electrografting of non-conducting polymers onto conducting surfaces. This work was achieved by manufacturing an original Atomic Force Microscopy-Scanning ElectroChemical Microscopy (AFM-SECM) electrode. The capabilities of the AFM-SECM-electrode were tested with the nano-electrografting of vinylic monomers initiated by aryl diazonium salts. Nano-electrochemical and technical processes were thoroughly described, so as to allow experiments reproducing. A plausible explanation of chemical and electrochemical mechanisms, leading to the nano-grafting process, was reported. This combined technique represents the first step towards improved nano-processes for the nano-electrografting. PMID:28348337

Synthesis and characterization of nano-sized CaCO3 in purified diet

NASA Astrophysics Data System (ADS)

Mulyaningsih, N. N.; Tresnasari, D. R.; Ramahwati, M. R.; Juwono, A. L.; Soejoko, D. S.; Astuti, D. A.

2017-07-01

The growth and development of animals depend strongly on the balanced nutrition in the diet. This research aims is to characterize the weight variations of nano-sized calcium carbonate (CaCO3) in purified diet that to be fed to animal model of rat. The nano-sized CaCO3 was prepared by milling the calcium carbonate particles for 20 hours at a rotation speed of 1000 rpm and resulting particle size in a range of 2-50 nm. Nano-sized CaCO3 added to purified diet to the four formulas that were identified as normal diet (N), deficiency calcium (DC), rich in calcium (RC), and poor calcium (PC) with containing in nano-sized CaCO3 much as 0.50 %, 0.00 %, 0.75 % and 0.25 % respectively. The nutritional content of the purified diet was proximate analyzed, it resulted as followed moisture, ash, fat, protein, crude fiber. The quantities of chemical element were analyzed by atomic absorption spectrometry (AAS), it resulted iron, magnesium, potassium and calcium. The results showed that N diet (Ca: 16,914.29 ppm) were suggested for healthy rats and RC diet (Ca: 33,696.13 ppm) for conditioned osteoporosis rats. The crystalline phases of the samples that were examined by X-ray diffraction showed that crystalline phase increased with the increasing concentration of CaCO3.

Ultrafine particle and fiber production in microgravity

NASA Technical Reports Server (NTRS)

Webb, George W. (Inventor)

1988-01-01

In a system and method for producing ultrafine particles and ultrafine fibers of a given source material by evaporating and condensing the material in a gas atmosphere that includes inert gas. A smaller, more narrow size distribution is accomplished by producing the particles and fibers in a microgravity environment in order to reduce particle coalescence caused by convection currents. Particle coalescence also is reduced in an Earth gravity environment by controlling the convection currents. Condensed particles are collected either by providing an electrostatic field or a spatially varying magnetic field or by causing the gas to move through a filter which collects the particles. Nonferromagnetic material fibers are produced and collected by electrodes which produce an electro- static field. Ferromagnetic particles are collected by spatially varying magnetic fields.

Graphene nano-devices and nano-composites for structural, thermal and sensing applications

NASA Astrophysics Data System (ADS)

Yavari, Fazel

that is macroscopic and easy to mass produce. The walls of the foam are comprised of a few layers of graphene sheets resulting in high sensitivity. We demonstrate parts-per-million (ppm) level detection of NH3 and NO2 in air at room-temperature using this sensor. Further, the foam is a mechanically robust and flexible macro-scale network that is easy to contact (without lithography) and can rival the durability and affordability of traditional sensors. Moreover, Joule-heating expels chemisorbed molecules from the foam’s surface leading to fully-reversible and low-power operation. In the second part of this dissertation the focus is on graphene platelets and their incorporation into polymer matrices to improve their mechanical and thermal properties. We demonstrate the synthesis and fatigue characterization of fiberglass/epoxy composites with various weight fractions of graphene platelets infiltrated into the epoxy resin as well as directly spray-coated on to the glass micro-fibers. Remarkably, only ~0.2wt.% of graphene additives enhances the fatigue life of the composite in the flexural bending mode by up to 1200-fold. By contrast, under uniaxial tensile fatigue conditions, the graphene fillers resulted in ~3 to 5-fold increase in fatigue life. In-situ ultrasound analysis of the nanocomposite during the cyclic fatigue test suggests that the graphene network toughens the fiberglass/epoxy-matrix interface and prevents the delamination/buckling of the glass micro-fibers under compressive stress. Such fatigue-resistant hierarchical materials show potential to improve the safety, reliability, and cost-effectiveness of fiber-reinforced composites that are increasingly the material of choice in the aerospace, automotive, marine, sports, bio-medical and wind energy industries. We also investigated the effect of graphene platelets on thermal properties of Graphene/1-Octadecanol composite as a nano-structured phase change material (PCM) for energy storage applications. The

Transverse strain measurements using fiber optic grating based sensors

NASA Technical Reports Server (NTRS)

Udd, Eric (Inventor)

1998-01-01

A system and method to sense the application of transverse stress to an optical fiber which includes a light source that producing a relatively wide spectrum light beam. The light beam is reflected or transmitted off of an optical grating in the core of an optical fiber that is transversely stressed either directly or by the exposure to pressure when the fiber is bifringent so that the optical fiber responds to the pressure to transversely stress its core. When transversely stressed, the optical grating produces a reflection or transmission from the light beam that has two peaks or minimums in its frequency spectrum whose spacing and/or spread are indicative of the forces applied to the fiber. One or more detectors sense the reflection or transmissions from the optical grating to produce an output representative of the applied force. Multiple optical gratings and detectors may be employed to simultaneously measure temperature or the forces at different locations along the fiber.

Study on effects of E-glass fiber hybrid composites enhanced with multi-walled carbon nanotubes under tensile load using full factorial design of experiments

NASA Astrophysics Data System (ADS)

Musthak, Md.; Madhavi, M.; Ahsanullah, F. M.

2017-08-01

Carbon nanotubes (CNT's) are attracting scientific and industrial interest by virtue of their outstanding characteristics. The present research problem deals with the fabrication and characterization of E-glass fiber composites enhanced by carbon nanotubes. In the present study, three factors with two levels are considered. Hence, the design is called 23 full factorial design of experiment. The process parameters considered for the present problem are weight of multi-walled carbon nanotubes, process to disperse nano-particles in resin, and orientation of woven fabric. In addition, their levels considered for the experiment are higher level (+1) and lower level (-1). Fabrication of E-glass fiber composites was carried out according to design, and the specimens were prepared with respect to the ASTM standards D3039-76 and tensile testing was performed. The results show that the nano-particulated composite plate can be manufactured by considering lower level nano-particles stirred with probe sonicator and plied-up with hybrid orientation.

Synthesis of nano silver on cellulosic denim fabric producing yellow colored garment with antibacterial properties.

PubMed

Maryan, Ali Sadeghian; Montazer, Majid; Harifi, Tina

2015-01-22

In this study, an aged-look denim fabric with antibacterial property was prepared in one single step process. For this purpose, the simultaneous antibacterial finishing and discoloration of denim fabric was carried out through reduction of indigo dye and silver nitrate by glucose in alkaline media using a conventional garment washing machine. The uniform distribution of silver nanoparticles on the fiber surface was confirmed by scanning electron microscope and energy dispersive X-ray spectroscopy. The treated fabrics were also characterized by X-ray diffraction (XRD) and Raman spectroscopy. Due to the color changes during the process, the color coordinates of the treated samples were also measured. Findings suggest the potential of the proposed method in producing old-look denim fabric with desirable yellow appearance and reasonable antibacterial activity against Staphylococcus aureus and Escherichia coli with low toxicity for human. Copyright © 2014 Elsevier Ltd. All rights reserved.

Carbon nano fibers reinforced composites origami inspired mechanical metamaterials with passive and active properties

NASA Astrophysics Data System (ADS)

Kshad, Mohamed Ali E.; D'Hondt, Clement; Naguib, Hani E.

2017-10-01

Core panels used for compression or impact damping are designed to dissipate energy and to reduce the transferred force and energy. They are designed to have high strain and deformation with low density. The geometrical configuration of such cores plays a significant role in redistributing the applied forces to dampen the compression and impact energy. Origami structures are renowned for affording large macroscopic deformation which can be employed for force redistribution and energy damping. The material selection for the fabrication of origami structures affects the core capacity to withstand compression and impact loads. Polymers are characterized by their high compression and impact resistance; the drawback of polymers is the low stiffness and elastic moduli compared with metallic materials. This work is focused on the study of the effect of Carbon Nano Fibers (CNF) on the global mechanical properties of the origami panel cores made of polymeric blends. The base matrix materials used were Polylactic Acid (PLA) and Thermoplastic Polyurethane (TPU) blends, and the percentages of the PLA/TPU were 100/0, 20/80, 65/35, 50/50, 20/80, and 0/100 as a percentage of weight. The weight percentages of CNF added to the polymeric blends were 1%, 3%, and 5%. This paper deals with the fabrication process of the polymeric reinforced blends and the origami cores, in order to predict the best fabrication conditions. The dynamic scanning calorimetry and the dynamic mechanical analyzer were used to test the reinforced blended base material for thermomechanical and viscoelastic properties. The origami core samples were fabricated using per-molded geometrical features and then tested for compression and impact properties. The results of the study were compared with previous published results which showed that there is considerable enhancement in the mechanical properties of the origami cores compared with the pure blended polymeric origami cores. The active properties of the origami

Electrospun cross linked rosin fibers

NASA Astrophysics Data System (ADS)

Baek, Woo-il; Nirmala, R.; Barakat, Nasser A. M.; El-Newehy, Mohamed H.; Al-Deyab, Salem S.; Kim, Hak Yong

2011-12-01

In this study, we describe the first reported preparation of rosin in fiber form through use of an electrospinning technique utilizing various solvent systems. The polymer concentration of the formed fiber was studied by using various solvents such as chloroform, ethanol, N-N dimethylformamide (DMF), tetrahydrofuran (THF), acetone, and methylene chloride (MC). An electrospray of the solution resulted in the beaded form of the rosin. By varying the polymer concentration with MC, we were then able to obtain uniform fibers. However, the fibers exhibited large diameter. We believe that it is possible to reduce the diameter of the rosin fibers through appropriate selection of electrospinning parameters. In addition, the morphological transitions from beads, to beaded fiber, to fiber were studied at different polymer concentrations. We propose a possible physical cross linking mechanism for the formation of rosin fibers during the electrospinning process. Our results demonstrate the feasibility of producing fiber nanostructures of rosin by using an electrospinning technique.

Nano-optical conveyor belt with waveguide-coupled excitation.

PubMed

Wang, Guanghui; Ying, Zhoufeng; Ho, Ho-pui; Huang, Ying; Zou, Ningmu; Zhang, Xuping

2016-02-01

We propose a plasmonic nano-optical conveyor belt for peristaltic transport of nano-particles. Instead of illumination from the top, waveguide-coupled excitation is used for trapping particles with a higher degree of precision and flexibility. Graded nano-rods with individual dimensions coded to have resonance at specific wavelengths are incorporated along the waveguide in order to produce spatially addressable hot spots. Consequently, by switching the excitation wavelength sequentially, particles can be transported to adjacent optical traps along the waveguide. The feasibility of this design is analyzed using three-dimensional finite-difference time-domain and Maxwell stress tensor methods. Simulation results show that this system is capable of exciting addressable traps and moving particles in a peristaltic fashion with tens of nanometers resolution. It is the first, to the best of our knowledge, report about a nano-optical conveyor belt with waveguide-coupled excitation, which is very important for scalability and on-chip integration. The proposed approach offers a new design direction for integrated waveguide-based optical manipulation devices and its application in large scale lab-on-a-chip integration.

Self-assembled Nano-layering at the Adhesive interface.

PubMed

Yoshida, Y; Yoshihara, K; Nagaoka, N; Hayakawa, S; Torii, Y; Ogawa, T; Osaka, A; Meerbeek, B Van

2012-04-01

According to the 'Adhesion-Decalcification' concept, specific functional monomers within dental adhesives can ionically interact with hydroxyapatite (HAp). Such ionic bonding has been demonstrated for 10-methacryloyloxydecyl dihydrogen phosphate (MDP) to manifest in the form of self-assembled 'nano-layering'. However, it remained to be explored if such nano-layering also occurs on tooth tissue when commercial MDP-containing adhesives (Clearfil SE Bond, Kuraray; Scotchbond Universal, 3M ESPE) were applied following common clinical application protocols. We therefore characterized adhesive-dentin interfaces chemically, using x-ray diffraction (XRD) and energy-dispersive x-ray spectroscopy (EDS), and ultrastructurally, using (scanning) transmission electron microscopy (TEM/STEM). Both adhesives revealed nano-layering at the adhesive interface, not only within the hybrid layer but also, particularly for Clearfil SE Bond (Kuraray), extending into the adhesive layer. Since such self-assembled nano-layering of two 10-MDP molecules, joined by stable MDP-Ca salt formation, must make the adhesive interface more resistant to biodegradation, it may well explain the documented favorable clinical longevity of bonds produced by 10-MDP-based adhesives.

A Novel Bioinspired PVDF Micro/Nano Hair Receptor for a Robot Sensing System

PubMed Central

Li, Fei; Liu, Weiting; Stefanini, Cesare; Fu, Xin; Dario, Paolo

2010-01-01

This paper describes the concept and design of a novel artificial hair receptor for the sensing system of micro intelligent robots such as a cricket-like jumping mini robot. The concept is inspired from the natural hair receptor of animals, also called cilium or filiform hair by different research groups, which is usually used as a vibration receptor or a flow detector by insects, mammals and fishes. The suspended fiber model is firstly built and the influence of scaling down is analyzed theoretically. The design of this artificial hair receptor is based on aligned suspended PVDF (polyvinylidene fluoride) fibers, manufactures with a novel method called thermo-direct drawing technique, and aligned suspended submicron diameter fibers are thus successfully fabricated on a flexible Kapton. In the post process step, some key problems such as separated electrodes deposition along with the fiber drawing direction and poling of micro/nano fibers to impart them with good piezoeffective activity have been presented. The preliminary validation experiments show that the artificial hair receptor has a reliable response with good sensibility to external pressure variation and, medium flow as well as its prospects in the application on sensing system of mini/micro bio-robots. PMID:22315581

Lab-on-Fiber devices as an all around platform for sensing

NASA Astrophysics Data System (ADS)

Ricciardi, A.; Consales, M.; Quero, G.; Crescitelli, A.; Esposito, E.; Cusano, A.

2013-12-01

"Lab-on-Fiber" technology is an emerging field envisioning a novel class of advanced, multifunctional photonic devices and components arising from the integration onto optical fibers of different materials at micro and nano-scale with suitable physical, chemical and biological properties. This new fascinating and intriguing research field thus proposes a new technological platform where functionalized materials, devices and components are constructed, embedded all together in a single optical fiber providing the necessary physical connections and light matter interaction, exploitable in both communication and sensing applications. This technological innovation would open the way for the creation of a novel technological world completely integrated in a single optical fiber conferring unique and unprecedented performances and functionality degree. Although, the benefits provided by such a technology can be easily understood, many research efforts are, however, required to translate the vision in a technological reality. Indeed, the main issue to address concerns the identification and definition of viable fabrication methodologies, routes and strategies enabling the integration of a large set of functional materials at sub wavelength scale onto non conventional substrates as the case of optical fibers.

Microscopy with multimode fibers

NASA Astrophysics Data System (ADS)

Moser, Christophe; Papadopoulos, Ioannis; Farahi, Salma; Psaltis, Demetri

2013-04-01

Microscopes are usually thought of comprising imaging elements such as objectives and eye-piece lenses. A different type of microscope, used for endoscopy, consists of waveguiding elements such as fiber bundles, where each fiber in the bundle transports the light corresponding to one pixel in the image. Recently a new type of microscope has emerged that exploits the large number of propagating modes in a single multimode fiber. We have successfully produced fluorescence images of neural cells with sub-micrometer resolution via a 200 micrometer core multimode fiber. The method for achieving imaging consists of using digital phase conjugation to reproduce a focal spot at the tip of the multimode fiber. The image is formed by scanning the focal spot digitally and collecting the fluorescence point by point.

MD Simulation on Collision Behavior Between Nano-Scale TiO₂ Particles During Vacuum Cold Spraying.

PubMed

Yao, Hai-Long; Yang, Guan-Jun; Li, Chang-Jiu

2018-04-01

Particle collision behavior influences significantly inter-nano particle bonding formation during the nano-ceramic coating deposition by vacuum cold spraying (or aerosol deposition method). In order to illuminate the collision behavior between nano-scale ceramic particles, molecular dynamic simulation was applied to explore impact process between nano-scale TiO2 particles through controlling impact velocities. Results show that the recoil efficiency of the nano-scale TiO2 particle is decreased with the increase of the impact velocity. Nano-scale TiO2 particle exhibits localized plastic deformation during collision at low velocities, while it is intensively deformed by collision at high velocities. This intensive deformation promotes the nano-particle adhesion rather than rebounding off. A relationship between the adhesion energy and the rebound energy is established for the bonding formation of the nano-scale TiO2 particle. The adhesion energy required to the bonding formation between nano-scale ceramic particles can be produced by high velocity collision.

Highly filled formaldehyde-free natural fiber polypropylene composites

Treesearch

Anand R. Sanadi; Daniel F. Caulfield

2000-01-01

Considerable interest has been generated in the use of lignocellulosic fibers and wastes (both agricultural and wood based) as fillers and reinforcements in thermoplastics. In general, present technologies limit fiber loading in thermoplastics to about 50% by weight of fiber. To produce high fiber content composites for commercial use while maintaining adequate...

CVD Fiber Coatings for Al2O3/NiAl Composites

NASA Technical Reports Server (NTRS)

Boss, Daniel E.

1995-01-01

While sapphire-fiber-reinforced nickel aluminide (Al2O3/NiAl) composites are an attractive candidate for high-temperature structures, the significant difference in the coefficient of thermal expansion between the NiAl matrix and the sapphire fiber creates substantial residual stresses in the composite. This study seeks to produce two fiber-coating systems with the potential to reduce the residual stresses in the sapphire/NiAl composite system. Chemical vapor deposition (CVD) was used to produce both the compensating and compliant-fiber coatings for use in sapphire/NiAl composites. A special reactor was designed and built to produce the FGM and to handle the toxic nickel precursors. This process was successfully used to produce 500-foot lengths of fiber with coating thicknesses of approximately 3 microns, 5 microns, and 10 microns.

Fiber-Optic Strain Sensors With Linear Characteristics

NASA Technical Reports Server (NTRS)

Egalon, Claudio O.; Rogowski, Robert S.

1993-01-01

Fiber-optic modal domain strain sensors having linear characteristics over wide range of strains proposed. Conceived in effort to improve older fiber-optic strain sensors. Linearity obtained by appropriate choice of design parameters. Pattern of light and dark areas at output end of optical fiber produced by interference between electromagnetic modes in which laser beam propagates in fiber. Photodetector monitors intensity at one point in pattern.

Lightweight Aluminum/Nano composites for Automotive Drive Train Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chelluri, Bhanumathi; Knoth, Edward A.; Schumaker, Edward J.

2012-12-14

During Phase I, we successfully processed air atomized aluminum powders via Dynamic Magnetic Compaction (DMC) pressing and subsequent sintering to produce parts with properties similar to wrought aluminum. We have also showed for the first time that aluminum powders can be processed without lubes via press and sintering to 100 % density. This will preclude a delube cycle in sintering and promote environmentally friendly P/M processing. Processing aluminum powders via press and sintering with minimum shrinkage will enable net shape fabrication. Aluminum powders processed via a conventional powder metallurgy process produce too large a shrinkage. Because of this, sinter partsmore » have to be machined into specific net shape. This results in increased scrap and cost. Fully sintered aluminum alloy under this Phase I project has shown good particle-to-particle bonding and mechanical properties. We have also shown the feasibility of preparing nano composite powders and processing via pressing and sintering. This was accomplished by dispersing nano silicon carbide (SiC) powders into aluminum matrix comprising micron-sized powders (<100 microns) using a proprietary process. These composite powders of Al with nano SiC were processed using DMC press and sinter process to sinter density of 85-90%. The process optimization along with sintering needs to be carried out to produce full density composites.« less

A nano-delivery system for bioactive ingredients using supercritical carbon dioxide and its release behaviors.

PubMed

Situ, Wenbei; Song, Xianliang; Luo, Shucan; Liang, Yan

2017-08-01

For the purpose of ensuring the bioavailability of bioactive ingredients, a nano-delivery system with low toxicity was developed using supercritical carbon dioxide (SC-CO 2 ). Compared to thin-film hydration (TFH), obtaining nano-scale liposomes is easier using SC-CO 2 . The characteristic of these liposomes was also demonstrated by the analysis of particle size and morphology. An in vitro release study showed that liposomes produced using SC-CO 2 were resistant to low pH in simulated gastric conditions. In a simulated intestinal environment, enteric solubility of these liposomes was enhanced, which are important properties for controlled releasing bioactive ingredient. Furthermore, SC-CO 2 -produced liposomes had a higher storage stability than those produced using TFH. Analysis of the organic solvent residue in the liposomes by gas chromatography-mass spectrometry (GC-MS) indicated that SC-CO 2 -produced liposomes had lower toxicity than those produced by TFH. A chemical free nano-delivery system using SC-CO 2 has been revealed for storage and controlled release of bioactive ingredients. Copyright © 2017 Elsevier Ltd. All rights reserved.

Drainage and fractionation of wood fibers in a flotation froth

Treesearch

J.Y. Zhu; Freya Tan

2005-01-01

Understanding fiber fractionation in a froth is very important to the quality of recovered fibers in flotation deinking operations. Fiber length is a very important fiber quality parameter in paper-making. For example, long fibers tend to produce a paper with higher tear strength than short fibers. In this study, fibers in froth collected at different froth drainage...

Photocatalytic treatment of RDX wastewater with nano-sized titanium dioxide.

PubMed

Liu, Zongkuan; He, Yanling; Li, Feng; Liu, Yonghong

2006-09-01

The polynitramines, hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), are important military explosives and regulated toxic hazardous compounds. Production, testing and use of the compounds has resulted in numerous acres of contaminated soils and groundwater near many munitions facilities. Economical and efficient methods for treatment of wastewater and cleanup of soils or groundwater containing RDX and HMX are needed. This study focuses on the photocatalytic treatment of RDX wastewater with nano-sized titanium dioxide (nano-TiO2) under simulated sunlight, whose intensity and wavelength are similar to that of the real sunlight in Xi'an at noon. The objective is to determine the potential for RDX destruction with nano-TiO2 in aqueous solution. An activated carbon fiber (ACF) cloth-loaded with nano-TiO2 was put into the RDX containing solution, and the concentration of RDX was measured (by HPLC-UV) at regular time intervals under simulated sunlight. The RDX degradation percentage of the photocatalytic process is higher than that of Fenton oxidation before 80 min, equivalent after 80 min, and it reaches 95% or above after 120 min. The nano-TiO2 catalyst can be used repeatedly. The photocatalytic degradation kinetics of RDX under simulated sunlight can be described by a first-order reaction kinetics equation. The possible degradation mechanism of RDX was presented and the degradation performance was compared with that of biological method. It was demonstrated that the degradation of RDX wastewater is very effective with nano-TiO2 as the photocatalytic catalyst under simulated sunlight. The efficiency of the nano-TiO2 catalyst for RDX degradation under simulated sunlight is nearly identical to that of Fenton oxidation. To date, a number of catalysts show poor absorption and utilization of sunlight, and still need ultraviolet light irradiation during wastewater degradation. The nano-TiO2 used in the described

Integrated double-clad photonic crystal fiber amplifier

NASA Astrophysics Data System (ADS)

Liu, Jun; Gu, Yanran; Chen, Zilun

2017-10-01

This paper studies and fabricates an integrated double-clad photonic crystal fiber amplifier, which overcomes the shortcomings of space application and makes full use of excellent property of double-clad photonic crystal fiber. In the experiment, the (6 + 1) × 1 end-pump coupler with DC-PCF is fabricated. The six pump fibers are fabricated with 105 / 125μm (NA = 0.22) multi-mode fiber. The signal fiber is made of ordinary single-mode fiber SMF-28. Then we spliced the tapered fiber bundle to photonic crystal fiber. At last, we produce double-clad photonic crystal fiber with an end-cap that are able to withstand high average power and protect the system. We have fabricated an integrated Yb-double-clad photonic crystal fiber amplifier.

SWCNTs-based nanocomposites as sensitive coatings for advanced fiber optic chemical nanosensors

NASA Astrophysics Data System (ADS)

Consales, M.; Crescitelli, A.; Penza, M.; Aversa, P.; Giordano, M.; Cutolo, A.; Cusano, A.

2008-04-01

In this work, the feasibility of exploiting novel Cadmium Arachidate (CdA)/single-walled carbon nanotubes (SWCNTs) based composites as sensitive coatings for the development of robust and high performances optoelectronic chemosensors able to work in liquid environments has been investigated and proved. Here, nano-composite sensing layers have been transferred upon the distal end of standard optical fibers by the Langmuir-Blodgett (LB) technique. Reflectance measurements have been carried out to monitor ppm concentration of chemicals in water through the changes in the optical and geometrical features of the sensing overlay induced by the interaction with the analyte molecules. Preliminary experimental results evidence that such nanoscale coatings integrated with the optical fiber technology offers great potentialities for the room temperature detection of chemical traces in water and lead to significant improvements of the traditional fiber optic sensors based on SWCNTs layers.

Correlating Detergent Fiber Analysis and Dietary Fiber Analysis Data for Corn Stover

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wolfrum, E. J.; Lorenz, A. J.; deLeon, N.

There exist large amounts of detergent fiber analysis data [neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL)] for many different potential cellulosic ethanol feedstocks, since these techniques are widely used for the analysis of forages. Researchers working in the area of cellulosic ethanol are interested in the structural carbohydrates in a feedstock (principally glucan and xylan), which are typically determined by acid hydrolysis of the structural fraction after multiple extractions of the biomass. These so-called dietary fiber analysis methods are significantly more involved than detergent fiber analysis methods. The purpose of this study was to determinemore » whether it is feasible to correlate detergent fiber analysis values to glucan and xylan content determined by dietary fiber analysis methods for corn stover. In the detergent fiber analysis literature cellulose is often estimated as the difference between ADF and ADL, while hemicellulose is often estimated as the difference between NDF and ADF. Examination of a corn stover dataset containing both detergent fiber analysis data and dietary fiber analysis data predicted using near infrared spectroscopy shows that correlations between structural glucan measured using dietary fiber techniques and cellulose estimated using detergent techniques, and between structural xylan measured using dietary fiber techniques and hemicellulose estimated using detergent techniques are high, but are driven largely by the underlying correlation between total extractives measured by fiber analysis and NDF/ADF. That is, detergent analysis data is correlated to dietary fiber analysis data for structural carbohydrates, but only indirectly; the main correlation is between detergent analysis data and solvent extraction data produced during the dietary fiber analysis procedure.« less

Apparatus for producing carbon-coated nanoparticles and carbon nanospheres

DOEpatents

Perry, W. Lee; Weigle, John C.; Phillips, Jonathan

2015-10-20

An apparatus for producing carbon-coated nano- or micron-scale particles comprising a container for entraining particles in an aerosol gas, providing an inlet for carbon-containing gas, providing an inlet for plasma gas, a proximate torch for mixing the aerosol gas, the carbon-containing gas, and the plasma gas, bombarding the mixed gases with microwaves, and providing a collection device for gathering the resulting carbon-coated nano- or micron-scale particles. Also disclosed is a method and apparatus for making hollow carbon nano- or micro-scale spheres.

Multi-kW single fiber laser based on an extra large mode area fiber design

NASA Astrophysics Data System (ADS)

Langner, Andreas; Such, Mario; Schötz, Gerhard; Just, Florian; Leich, Martin; Schwuchow, Anka; Grimm, Stephan; Zimer, Hagen; Kozak, Marcin; Wedel, Björn; Rehmann, Georg; Bachert, Charley; Krause, Volker

2012-02-01

The quality of Yb-doped fused bulk silica produced by sintering of Yb-doped fused silica granulates has improved greatly in the past five years [1 - 4]. In particular, the refractive index and doping level homogeneity of such materials are excellent and we achieved excellent background fiber attenuation of the active core material down to about 20 dB/km at 1200 nm. The improvement of the Yb-doped fused bulk silica has enabled the development of multi-kW fiber laser systems based on a single extra large multimode laser fiber (XLMA fiber). When a single active fiber is used in combination with the XLMA multimode fiber of 1200 μm diameter simple and robust high power fiber laser setups without complex fiber coupling and fiber combiner systems become possible. In this papper, we will discuss in detail the development of the core material based on Yb-doped bulk silica and the characterization of Yb-doped fibers with different core compositions. We will also report on the excellent performance of a 4 kW fiber laser based on a single XLMA-fiber and show the first experimental welding results of steel sheets achieved with such a laser.

Studies on mechanical properties of graphene based hybrid composites reinforced with kenaf/glass fiber

NASA Astrophysics Data System (ADS)

Kumar, S. C. Ramesh; Shivanand, H. K.; Vidayasagar, H. N.; Nagabhushan, V.

2018-04-01

The polymer composites are developed with natural fibers and fillers as a alternate material for some of the engineering applications in the field of automobiles and domestic purposes are being investigated. The natural fiber composites such as banana, sisal, jute, coir, kenaf and hemp polymer composites appear more effective due to their lightweight, higher specific strength, biodegradable and cost is low. The main objective is to prepare the Kenaf/Glass fiber hybrid composite filled with graphene as nano filler and to investigate the mechanical properties of hybrid composites. The different types of hybrid composites laminates are fabricated without filler, 0.5, 1 & 1.5Wt % of graphene by using kenaf and glass fiber as reinforcing material with epoxy resin. The specimen were prepared as per the ASTM standards and results shows that the mixing of graphene in epoxy resin improves the mechanical properties of hybrid composites.

Phonon Spectrum Engineering in Rolled-up Micro- and Nano-Architectures

DOE PAGES

Fomin, Vladimir M.; Balandin, Alexander A.

2015-10-10

We report on a possibility of efficient engineering of the acoustic phonon energy spectrum in multishell tubular structures produced by a novel high-tech method of self-organization of micro- and nano-architectures. The strain-driven roll-up procedure paved the way for novel classes of metamaterials such as single semiconductor radial micro- and nano-crystals and multi-layer spiral micro- and nano-superlattices. The acoustic phonon dispersion is determined by solving the equations of elastodynamics for InAs and GaAs material systems. It is shown that the number of shells is an important control parameter of the phonon dispersion together with the structure dimensions and acoustic impedance mismatchmore » between the superlattice layers. The obtained results suggest that rolled up nano-architectures are promising for thermoelectric applications owing to a possibility of significant reduction of the thermal conductivity without degradation of the electronic transport.« less

Phonon Spectrum Engineering in Rolled-up Micro- and Nano-Architectures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fomin, Vladimir M.; Balandin, Alexander A.

We report on a possibility of efficient engineering of the acoustic phonon energy spectrum in multishell tubular structures produced by a novel high-tech method of self-organization of micro- and nano-architectures. The strain-driven roll-up procedure paved the way for novel classes of metamaterials such as single semiconductor radial micro- and nano-crystals and multi-layer spiral micro- and nano-superlattices. The acoustic phonon dispersion is determined by solving the equations of elastodynamics for InAs and GaAs material systems. It is shown that the number of shells is an important control parameter of the phonon dispersion together with the structure dimensions and acoustic impedance mismatchmore » between the superlattice layers. The obtained results suggest that rolled up nano-architectures are promising for thermoelectric applications owing to a possibility of significant reduction of the thermal conductivity without degradation of the electronic transport.« less

Rice-like hollow nano-CaCO3 synthesis

NASA Astrophysics Data System (ADS)

Ulkeryildiz, Eda; Kilic, Sevgi; Ozdemir, Ekrem

2016-09-01

We have shown that Ca(OH)2 solution is a natural stabilizer for CaCO3 particles. We designed a CO2 bubbling crystallization reactor to produce nano-CaCO3 particles in homogenous size distribution without aggregation. In the experimental set-up, the crystallization region was separated from the stabilization region. The produced nanoparticles were removed from the crystallization region into the stabilization region before aggregation or crystal growth. It was shown that rice-like hollow nano-CaCO3 particles in about 250 nm in size were produced with almost monodispersed size distribution. The particles started to dissolve through their edges as CO2 bubbles were injected, which opened-up the pores inside the particles. At the late stages of crystallization, the open pores were closed as a result of dissolution-recrystallization of the newly synthesized CaCO3 particles. These particles were stable in Ca(OH)2 solution and no aggregation was detected. The present methodology can be used in drug encapsulation into inorganic CaCO3 particles for cancer treatment with some modifications.

Influence of attrition milling on nano-grain boundaries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rawers, J.; Cook, D.

1999-03-01

Nanostructured materials have a relatively large proportion of their atoms associated with the grain boundary, and the method used to develop the nano-grains has a strong influence on the resulting grain boundary structure. In this study, attrition milling iron powders and blends of iron powders produced micron-size particles composed of nano-size grains. Mechanical cold-working powder resulted in dislocation generation, multiplication, and congealing that produced grain refinement. As the grain size approached nano-dimensions, dislocations were no longer sustained within the grain and once generated, rapidly diffused to the grain boundary. Dislocations on the grain boundary strained the local lattice structure which,more » as the grain size decreased, became the entire grain. Mechanical alloying of substitutional aluminium atoms into iron powder resulted in the aluminium atoms substituting for iron atoms in the grain boundary cells and providing a grain boundary structure similar to that of the iron powder processed in argon. Attrition milling iron powder in nitrogen gas resulted in nitrogen atoms being adsorbed onto the particle surface. Continued mechanical milling infused the nitrogen atoms into interstitial lattice sites on the grain boundary which also contributed to expanding and straining the local lattice.« less

Effect of fiber fibrillation on impact and flexural strength of coir fiber reinforced epoxy hybrid composites

NASA Astrophysics Data System (ADS)

Mawardi, I.; Jufriadi; Hanif

2018-03-01

This study aims to develop fiber-reinforced epoxy resin composites. This study presents the effect of fiber fibrillation on the impact and flextural strength of the epoxy hybrid composite reinforced by coir fiber. Coir is soaked in 5% NaOH solution for 5 hours. Then fiber is rocessed using a blender of 2000 rpm density fibrillation. The length of time the fibrillation varied for 10, 20 and 30 minutes. Volume fraction of 30% fiber and matrix 70% composited. The composite uses a matrix of epoxy by hand lay up method. The implemented tests are impact and flexural tests. The test results show fiber fibrillation treatment can improve the composite mechanical properties. The highest impact and flexural strength, 24.45 kJ/m2 and 87.91 MPa were produced with fiber fibrillation for 10 minutes.

Multicolor, Fluorescent Supercapacitor Fiber.

PubMed

Liao, Meng; Sun, Hao; Zhang, Jing; Wu, Jingxia; Xie, Songlin; Fu, Xuemei; Sun, Xuemei; Wang, Bingjie; Peng, Huisheng

2017-10-05

Fiber-shaped supercapacitors have attracted broad attentions from both academic and industrial communities due to the demonstrated potentials as next-generation power modules. However, it is important while remains challenging to develop dark-environment identifiable supercapacitor fibers for enhancement on operation convenience and security in nighttime applications. Herein, a novel family of colorful fluorescent supercapacitor fibers has been produced from aligned multi-walled carbon nanotube sheets. Fluorescent dye particles are introduced and stably anchored on the surfaces of aligned multi-walled carbon nanotubes to prepare hybrid fiber electrodes with a broad range of colors from red to purple. The fluorescent component in the dye introduces fluorescent indication capability to the fiber, which is particularly promising for flexible and wearable devices applied in dark environment. In addition, the colorful fluorescent supercapacitor fibers also maintain high electrochemical performance under cyclic bending and charge-discharge processes. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Utilization of corn fiber for production of schizophyllan

USDA-ARS?s Scientific Manuscript database

Corn fiber is an abundant lignocellulosic biomass resource produced during the wet milling of corn. Although corn fiber is recalcitrant to enzymatic digestion, the fungus Schizophyllum commune was able to directly utilize corn fiber for production of the valuable bioproduct, schizophyllan. Schizophy...

Progress in Nano-Engineered Anodic Aluminum Oxide Membrane Development.

PubMed

Poinern, Gerrard Eddy Jai; Ali, Nurshahidah; Fawcett, Derek

2011-02-25

The anodization of aluminum is an electro-chemical process that changes the surface chemistry of the metal, via oxidation, to produce an anodic oxide layer. During this process a self organized, highly ordered array of cylindrical shaped pores can be produced with controllable pore diameters, periodicity and density distribution. This enables anodic aluminum oxide (AAO) membranes to be used as templates in a variety of nanotechnology applications without the need for expensive lithographical techniques. This review article is an overview of the current state of research on AAO membranes and the various applications of nanotechnology that use them in the manufacture of nano-materials and devices or incorporate them into specific applications such as biological/chemical sensors, nano-electronic devices, filter membranes and medical scaffolds for tissue engineering.

Progress in Nano-Engineered Anodic Aluminum Oxide Membrane Development

PubMed Central

Poinern, Gerrard Eddy Jai; Ali, Nurshahidah; Fawcett, Derek

2011-01-01

The anodization of aluminum is an electro-chemical process that changes the surface chemistry of the metal, via oxidation, to produce an anodic oxide layer. During this process a self organized, highly ordered array of cylindrical shaped pores can be produced with controllable pore diameters, periodicity and density distribution. This enables anodic aluminum oxide (AAO) membranes to be used as templates in a variety of nanotechnology applications without the need for expensive lithographical techniques. This review article is an overview of the current state of research on AAO membranes and the various applications of nanotechnology that use them in the manufacture of nano-materials and devices or incorporate them into specific applications such as biological/chemical sensors, nano-electronic devices, filter membranes and medical scaffolds for tissue engineering. PMID:28880002

Mechanical Property Evaluation of Palm/Glass Sandwiched Fiber Reinforced Polymer Composite in Comparison with few natural composites

NASA Astrophysics Data System (ADS)

Raja Dhas, J. Edwin; Pradeep, P.

2017-10-01

Natural fibers available plenty can be used as reinforcements in development of eco friendly polymer composites. The less utilized palm leaf stalk fibers sandwiched with artificial glass fibers was researched in this work to have a better reinforcement in preparing a green composite. The commercially available polyester resin blend with coconut shell filler in nano form was used as matrix to sandwich these composites. Naturally available Fibers of palm leaf stalk, coconut leaf stalk, raffia and oil palm were extracted and treated with potassium permanganate solution which enhances the properties. For experimentation four different plates were fabricated using these fibers adopting hand lay-up method. These sandwiched composite plates are further machined to obtain ASTM standards Specimens which are mechanically tested as per standards. Experimental results reveal that the alkali treated palm leaf stalk fiber based polymer composite shows appreciable results than the others. Hence the developed composite can be recommended for fabrication of automobile parts.

Mid-infrared chalcogenide fiber devices for medical applications

NASA Astrophysics Data System (ADS)

Chenard, Francois; Alvarez, Oseas; Buff, Andrew

2018-02-01

High-purity chalcogenide glasses and fiber draw processes enable the production of state-of-the-art mid-infrared fibers for 1.5 to 10 micron transmission. Multimode and single-mode mid-infrared fibers are produced with low-loss (<0.2 dB/m), high tensile strength (>25 kpsi), and high power laser handling capability (>11.8 MW/cm2). Chalcogenide fibers support the development of cutting-edge devices for mid-infrared medical applications. Connectorized cables transmit laser power to a sample or mid-infrared radiation to a detector. Broadband antireflection microstructures are thermally stamped on the chalcogenide fiber tip to reduce the surface reflection from 17% to <5%. Also custom fiber-optic probe bundles are made with multiple fiber legs (source, sample, signal) for reflection and backscatter spectroscopy measurement. For example, a 7 x 1 fiber probe bundle is presented. Additionally imaging fiber bundle is made to perform remote thermal and spectral imaging. Square preforms are drawn, stacked, squared and fused multiple times to produce a 64 x 64 imaging fiber bundle with fiber pixel size of 34 microns and the numerical aperture of 0.3. The 2- meter long imaging fiber bundle is small (2.2 mm x 2.2 mm), flexible (bend radius >10 mm) and transmits over the spectral range of 1.5 to 6.5 micron.

Fiber Scrambling for High Precision Spectrographs

NASA Astrophysics Data System (ADS)

Kaplan, Zachary; Spronck, J. F. P.; Fischer, D.

2011-05-01

The detection of Earth-like exoplanets with the radial velocity method requires extreme Doppler precision and long-term stability in order to measure tiny reflex velocities in the host star. Recent planet searches have led to the detection of so called "super-Earths” (up to a few Earth masses) that induce radial velocity changes of about 1 m/s. However, the detection of true Earth analogs requires a precision of 10 cm/s. One of the largest factors limiting Doppler precision is variation in the Point Spread Function (PSF) from observation to observation due to changes in the illumination of the slit and spectrograph optics. Thus, this stability has become a focus of current instrumentation work. Fiber optics have been used since the 1980's to couple telescopes to high-precision spectrographs, initially for simpler mechanical design and control. However, fiber optics are also naturally efficient scramblers. Scrambling refers to a fiber's ability to produce an output beam independent of input. Our research is focused on characterizing the scrambling properties of several types of fibers, including circular, square and octagonal fibers. By measuring the intensity distribution after the fiber as a function of input beam position, we can simulate guiding errors that occur at an observatory. Through this, we can determine which fibers produce the most uniform outputs for the severest guiding errors, improving the PSF and allowing sub-m/s precision. However, extensive testing of fibers of supposedly identical core diameter, length and shape from the same manufacturer has revealed the "personality” of individual fibers. Personality describes differing intensity patterns for supposedly duplicate fibers illuminated identically. Here, we present our results on scrambling characterization as a function of fiber type, while studying individual fiber personality.

Microstructure of the smart composite structures with embedded fiber optic sensing nerves

NASA Astrophysics Data System (ADS)

Liu, Jingyuan; Luo, Fei; Li, Changchun; Ma, Naibin

1997-11-01

The composite structures with embedded optical fiber sensors construct a smart composite structure system, which may have the characteristics of the in-service self-measurement, self- recognition and self-judgement action. In the present work, we studied the microstructures of carbon/epoxy composite laminates with embedded sensing optical fibers, and the integration of optical fiber with composites was also discussed. The preliminary experiment results show that because of the difference between the sensing optical fibers and the reinforcing fibers in their size, the microstructure of the composites with embedded optical fibers will produce partial local changes in the area of embedded optical fiber, these changes may affect the mechanical properties of composite structures. When the optical fibers are embedded parallel to the reinforcing fibers, due to the composite prepregs are formed under a press action during its curing process, the reinforcing fibers can be arranged equably around the optical fibers. But when the optical fibers are embedded perpendicularly to the reinforcement fibers, the resin rich pocket will appear in the composite laminates surrounding the embedded optical fiber. The gas holes will be easily produced in these zones which may produce a premature failure of the composite structure. The photoelastic experiments are also given in the paper.

Spontaneous Differentiation of Human Mesenchymal Stem Cells on Poly-Lactic-Co-Glycolic Acid Nano-Fiber Scaffold.

PubMed

Sonomoto, Koshiro; Yamaoka, Kunihiro; Kaneko, Hiroaki; Yamagata, Kaoru; Sakata, Kei; Zhang, Xiangmei; Kondo, Masahiro; Zenke, Yukichi; Sabanai, Ken; Nakayamada, Shingo; Sakai, Akinori; Tanaka, Yoshiya

2016-01-01

Mesenchymal stem cells (MSCs) have immunosuppressive activity and can differentiate into bone and cartilage; and thus seem ideal for treatment of rheumatoid arthritis (RA). Here, we investigated the osteogenesis and chondrogenesis potentials of MSCs seeded onto nano-fiber scaffolds (NFs) in vitro and possible use for the repair of RA-affected joints. MSCs derived from healthy donors and patients with RA or osteoarthritis (OA) were seeded on poly-lactic-glycolic acid (PLGA) electrospun NFs and cultured in vitro. Healthy donor-derived MSCs seeded onto NFs stained positive with von Kossa at Day 14 post-stimulation for osteoblast differentiation. Similarly, MSCs stained positive with Safranin O at Day 14 post-stimulation for chondrocyte differentiation. Surprisingly, even cultured without any stimulation, MSCs expressed RUNX2 and SOX9 (master regulators of bone and cartilage differentiation) at Day 7. Moreover, MSCs stained positive for osteocalcin, a bone marker, and simultaneously also with Safranin O at Day 14. On Day 28, the cell morphology changed from a spindle-like to an osteocyte-like appearance with processes, along with the expression of dentin matrix protein-1 (DMP-1) and matrix extracellular phosphoglycoprotein (MEPE), suggesting possible differentiation of MSCs into osteocytes. Calcification was observed on Day 56. Expression of osteoblast and chondrocyte differentiation markers was also noted in MSCs derived from RA or OA patients seeded on NFs. Lactic acid present in NFs potentially induced MSC differentiation into osteoblasts. Our PLGA scaffold NFs induced MSC differentiation into bone and cartilage. NFs induction process resembled the procedure of endochondral ossification. This finding indicates that the combination of MSCs and NFs is a promising therapeutic technique for the repair of RA or OA joints affected by bone and cartilage destruction.

Effect of Nano-SiO₂ on the Early Hydration of Alite-Sulphoaluminate Cement.

PubMed

Sun, Jinfeng; Xu, Zhiqiang; Li, Weifeng; Shen, Xiaodong

2017-05-03

The impact of nano-SiO₂ on the early hydration properties of alite-sulphoaluminate (AC$A) cement was investigated with a fixed water to solid ratio ( w / s ) of one. Nano-SiO₂ was used in partial substitution of AC$A cement at zero, one and three wt %. Calorimetry, X-ray diffraction (XRD), thermogravimetric/derivative thermogravimetric (TG/DTG), mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM) analyses were used to characterize the hydration and hydrates of the blended cement. The hydration of the AC$A cement was significantly promoted, resulting in an increase of the heat released with the addition of nano-SiO₂. Phase development composition analysis showed that nano-SiO₂ had no effect on the type of crystalline hydration products of the AC$A cement. Moreover, nano-SiO₂ showed significant positive effects on pore refinement where the total porosity decreased by 54.09% at three days with the inclusion of 3% nano-SiO₂. Finally, from the SEM observations, nano-SiO₂ was conducive to producing a denser microstructure than that of the control sample.

SiGe nano-heteroepitaxy on Si and SiGe nano-pillars.

PubMed

Mastari, M; Charles, M; Bogumilowicz, Y; Thai, Q M; Pimenta-Barros, P; Argoud, M; Papon, A M; Gergaud, P; Landru, D; Kim, Y; Hartmann, J M

2018-07-06

In this paper, SiGe nano-heteroepitaxy on Si and SiGe nano-pillars was investigated in a 300 mm industrial reduced pressure-chemical vapour deposition tool. An integration scheme based on diblock copolymer patterning was used to fabricate nanometre-sized templates for the epitaxy of Si and SiGe nano-pillars. Results showed highly selective and uniform processes for the epitaxial growth of Si and SiGe nano-pillars. 200 nm thick SiGe layers were grown on Si and SiGe nano-pillars and characterised by atomic force microscopy, x-ray diffraction and transmission electron microscopy. Smooth SiGe surfaces and full strain relaxation were obtained in the 650 °C-700 °C range for 2D SiGe layers grown either on Si or SiGe nano-pillars.

Responsiveness of emulsions stabilized by lactoferrin nano-particles to simulated intestinal conditions.

PubMed

Meshulam, Dafna; Lesmes, Uri

2014-01-01

There is an upsurge of interest in the use of nano-particles to fabricate emulsions and modulate their functionality, with particular emphasis on modulating emulsion digestive fate. Food grade nano-particles formed through controlled processing and electrostatic biopolymer interactions are yet to be systematically studied for their ability to stabilize emulsions and modulate emulsion digestibility. This study focused on the responsiveness of emulsions stabilized by lactoferrin (LF) nano-particles (NPs) and dietary fibers to key digestive parameters. Compared to native LF, LF-NPs comprised emulsion exhibited elevated creaming rates as evident from accelerated stability tests performed by analytical centrifugation. The electrostatic deposition of alginate or carrageenan onto the LF-NPs significantly improved the stability of the corresponding emulsions. Further, the use of various nano-particles showed to have both beneficial and deleterious effects on emulsion responsiveness to pH (2.0 < pH < 10.0), CaCl2 (0-40 mM) and bile (0-25 mg mL(-1)). Simulated pH-stat lipolysis experiments show that the use of LF or LF-NPs had no marked effect on lipolysis. Intriguingly, the use of LF-NPs and alginate reduced emulsion lipolysis by 14% while the use of LF-NPs and carrageenan increased lipolysis by 10%. Microscopy images as well as droplet characterization in terms of size and charge indicate that the altered emulsion responsiveness may be due to physical differences in emulsion properties (e.g. droplet size) and overall organization during digestion (e.g. aggregation vs. coalescence). Overall, this study's insights could prospectively be used to harness protein nano-particles to tweak emulsion behavior during digestion.

Self-Powered Active Sensor with Concentric Topography of Piezoelectric Fibers

NASA Astrophysics Data System (ADS)

Fuh, Yiin Kuen; Huang, Zih Ming; Wang, Bo Sheng; Li, Shan Chien

2017-01-01

In this study, we demonstrated a flexible and self-powered sensor based on piezoelectric fibers in the diameter range of nano- and micro-scales. Our work is distinctively different from previous electrospinning research; we fabricated this apparatus precisely via near-field electrospinning which has a spectacular performance to harvest mechanical deformation in arbitrary direction and a novel concentrically circular topography. There are many piezoelectric devices based on electrospinning polymeric fibers. However, the fibers were mostly patterned in parallel lines and they could be actuated in limited direction only. To overcome this predicament, we re-arranged the parallel alignment into concentric circle pattern which made it possible to collect the mechanical energy whenever the deformation is along same axis or not. Despite the change of topography, the output voltage and current could still reach to 5 V and 400 nA, respectively, despite the mechanical deformation was from different direction. This new arbitrarily directional piezoelectric generator with concentrically circular topography (PGCT) allowed the piezoelectric device to harvest more mechanical energy than the one-directional alignment fiber-based devices, and this PGCT could perform even better output which promised more versatile and efficient using as a wearable electronics or sensor.

Nanostructured Diclofenac Sodium Releasing Material

NASA Astrophysics Data System (ADS)

Nikkola, L.; Vapalahti, K.; Harlin, A.; Seppälä, J.; Ashammakhi, N.

2008-02-01

Various techniques have been developed to produce second generation biomaterials for tissue repair. These include extrusion, molding, salt leaching, spinning etc, but success in regenerating tissues has been limited. It is important to develop porous material, yet with a fibrous structure for it to be biomimetic. To mimic biological tissues, the extra-cellular matrix usually contains fibers in nano scale. To produce nanostructures, self-assembly or electrospinning can be used. Adding a drug release function to such a material may advance applications further for use in controlled tissue repair. This turns the resulting device into a multifunctional porous, fibrous structure to support cells and drug releasing properties in order to control tissue reactions. A bioabsorbable poly(ɛ-caprolactone-co-D,L lactide) 95/5 (PCL) was made into diluted solution using a solvent, to which was added 2w-% of diclofenac sodium (DS). Nano-fibers were made by electrospinning onto substrate. Microstructure of the resulting nanomat was studied using SEM and drug release profiles with UV/VIS spectroscopy. Thickness of the electrospun nanomat was about 2 mm. SEM analysis showed that polymeric nano-fibers containing drug particles form a highly interconnected porous nano structure. Average diameter of the nano-fibers was 130 nm. There was a high burst peak in drug release, which decreased to low levels after one day. The used polymer has slow a degradation rate and though the nanomat was highly porous with a large surface area, drug release rate is slow. It is feasible to develop a nano-fibrous porous structure of bioabsorbable polymer, which is loaded with test drug. Drug release is targeted at improving the properties of biomaterial for use in controlled tissue repair and regeneration.

Harsh environment fiber optic connectors/testing

NASA Astrophysics Data System (ADS)

Parker, Douglas A.

2014-09-01

Fiber optic systems are used frequently in military, aerospace and commercial aviation programs. There is a long history of implementing fiber optic data transfer for aircraft control, for harsh environment use in local area networks and more recently for in-flight entertainment systems. The advantages of fiber optics include high data rate capacity, low weight, immunity to EMI/RFI, and security from signal tapping. Technicians must be trained particularly to install and maintain fiber systems, but it is not necessarily more difficult than wire systems. However, the testing of the fiber optic interconnection system must be conducted in a standardized manner to assure proper performance. Testing can be conducted with slight differences in the set-up and procedure that produce significantly different test results. This paper reviews various options of interconnect configurations and discusses how these options can affect the performance, maintenance required and longevity of a fiber optic system, depending on the environment. Proper test methods are discussed. There is a review of the essentials of proper fiber optic testing and impact of changing such test parameters as input launch conditions, wavelength considerations, power meter options and the basic methods of testing. This becomes important right from the start when the supplier test data differs from the user's data check upon receiving the product. It also is important in periodic testing. Properly conducting the fiber optic testing will eliminate confusion and produce meaningful test results for a given harsh environment application.

SHI induced nano track polymer filters and characterization

NASA Astrophysics Data System (ADS)

Vijay, Y. K.

2009-07-01

Swift heavy ion irradiation produces damage in polymers in the form of latent tracks. Latent tracks can be enlarged by etching it in a suitable etchant and thus nuclear track etch membrane can be formed for gas permeation / purification in particular for hydrogen where the molecular size is very small. By applying suitable and controlled etching conditions well defined tracks can be formed for specific applications of the membranes. After etching gas permeation method is used for characterizing the tracks. In the present work polycarbonate (PC) of various thickness were irradiated with energetic ion beam at Inter University Accelerator Centre (IUAC), New Delhi. Nuclear tracks were modified by etching the PC in 6N NaOH at 60 (±1) °C from both sides for different times to produce track etch membranes. At critical etch time the etched pits from both the sides meet a rapid increase in gas permeation was observed. Permeability of hydrogen and carbon dioxide has been measured in samples etched for different times. The latent tracks produced by SHI irradiation in the track etch membranes show enhancement of free volume of the polymer. Nano filters are separation devices for the mixture of gases, different ions in the solution and isotopes and isobars separations. The polymer thin films with controlled porosity finding it self as best choice. However, the permeability and selectivity of these polymer based membrane filters are very important at the nano scale separation. The Swift Heavy Ion (SHI) induced nuclear track etched polymeric films with controlled etching have been attempted and characterized as nano scale filters.

High-voltage nano-oxidation in deionized water and atmospheric environments by atomic force microscopy.

PubMed

Huang, Jen-Ching; Chen, Chung-Ming

2012-01-01

This study used atomic force microscopy (AFM), metallic probes with a nanoscale tip, and high-voltage generators to investigate the feasibility of high-voltage nano-oxidation processing in deionized water (DI water) and atmospheric environments. Researchers used a combination of wire-cutting and electrochemical etching to transform a 20-μm-thick stainless steel sheet into a conductive metallic AFM probe with a tip radius of 60 nm, capable of withstanding high voltages. The combination of AFM, high-voltage generators, and nanoscale metallic probes enabled nano-oxidation processing at 200 V in DI water environments, producing oxides up to 66.6 nm in height and 467.03 nm in width. Oxides produced through high-voltage nano-oxidation in atmospheric environments were 117.29 nm in height and 551.28 nm in width, considerably exceeding the dimensions of those produced in DI water. An increase in the applied bias voltage led to an apparent logarithmic increase in the height of the oxide dots in the range of 200-400 V. The performance of the proposed high-voltage nano-oxidation technique was relatively high with seamless integration between the AFM machine and the metallic probe fabricated in this study. © Wiley Periodicals, Inc.

3D carbon fiber mats/nano-Fe3O4 hybrid material with high electromagnetic shielding performance

NASA Astrophysics Data System (ADS)

Zhan, Yingqing; Long, Zhihang; Wan, Xinyi; Zhang, Jiemin; He, Shuangjiang; He, Yi

2018-06-01

To obtain high-performance electromagnetic shielding materials, structure and morphology are two key factors. We here developed an efficient and facial method to prepare high-performance 3D carbon nanofiber mats (CFM)/Fe3O4 hybrid electromagnetic shielding materials. For this purpose, the CFM were chemically modified by mussel-inspired poly-dopamine coating, which were further used as templates for decoration of Fe3O4 nanoparticles via solvothermal route. It was found that the Fe3O4 nano-spheres with diameters of 200-250 nm were uniformly coated on the surface of 3D carbon nanofibers. More importantly, the morphology and structure of resulting 3D carbon nanofiber mats/Fe3O4 hybrids could be easily controlled by altering the experiment parameters, which were examined by FT-IR, XPS, TGA, XRD, SEM, and TEM. The measured magnetic properties showed that saturation magnetism and coercivity increased from 13.4 to 39.7 emu/g and 85.3 to 104.6 Oe, respectively. The lowest reflectivity of resulting hybrid was calculated to be -47 dB at 10.0 GHz (2.5 mm). In addition, the reflectivity of 3D carbon nanofiber mats/Fe3O4 hybrid was less than -25 dB in the range of 7-13 GHz. Moreover, the resulting 3D carbon nanofiber mats/Fe3O4 hybrid exhibited an EMI shielding performance of -62.6 dB in the frequency range of 8.2-12.4 GHz. Therefore, 3D carbon fiber mats/Fe3O4 hybrids can be ideal EMI materials with strong absorption, low density, and wide absorption range.

Functional electrospun fibers for the treatment of human skin wounds.

PubMed

Wang, Jing; Windbergs, Maike

2017-10-01

Wounds are trauma induced defects of the human skin involving a multitude of endogenous biochemical events and cellular reactions of the immune system. The healing process is extremely complex and affected by the patient's physiological conditions, potential implications like infectious pathogens and inflammation as well as external factors. Due to increasing incidence of chronic wounds and proceeding resistance of infection pathogens, there is a strong need for effective therapeutic wound care. In this context, electrospun fibers with diameters in the nano- to micrometer range gain increasing interest. While resembling the structure of the native human extracellular matrix, such fiber mats provide physical and mechanical protection (including protection against bacterial invasion). At the same time, the fibers allow for gas exchange and prevent occlusion of the wound bed, thus facilitating wound healing. In addition, drugs can be incorporated within such fiber mats and their release can be adjusted by the material and dimensions of the individual fibers. The review gives a comprehensive overview about the current state of electrospun fibers for therapeutic application on skin wounds. Different materials as well as fabrication techniques are introduced including approaches for incorporation of drugs into or drug attachment onto the fiber surface. Against the background of wound pathophysiology and established therapy approaches, the therapeutic potential of electrospun fiber systems is discussed. A specific focus is set on interactions of fibers with skin cells/tissues as well as wound pathogens and strategies to modify and control them as key aspects for developing effective wound therapeutics. Further, advantages and limitations of controlled drug delivery from fiber mats to skin wounds are discussed and a future perspective is provided. Copyright © 2017 Elsevier B.V. All rights reserved.

High aspect ratio template and method for producing same for central and peripheral nerve repair

NASA Technical Reports Server (NTRS)

Sakamoto, Jeff S. (Inventor); Chan, Christina (Inventor); Tuszynski, Mark Henry (Inventor); Mehrotra, Sumit (Inventor); Gros, Thomas (Inventor)

2011-01-01

Millimeter to nano-scale structures manufactured using a multi-component polymer fiber matrix are disclosed. The use of dissimilar polymers allows the selective dissolution of the polymers at various stages of the manufacturing process. In one application, biocompatible matrixes may be formed with long pore length and small pore size. The manufacturing process begins with a first polymer fiber arranged in a matrix formed by a second polymer fiber. End caps may be attached to provide structural support and the polymer fiber matrix selectively dissolved away leaving only the long polymer fibers. These may be exposed to another product, such as a biocompatible gel to form a biocompatible matrix. The polymer fibers may then be selectively dissolved leaving only a biocompatible gel scaffold with the pores formed by the dissolved polymer fibers. The scaffolds may be used in, among other applications, the repair of central and peripheral nerves. Scaffolds for the repair of peripheral nerves may include a reservoir for the sustained release of nerve growth factor. The scaffolds may also include a multifunctional polyelectrolyte layer for the sustained release of nerve growth factor and enhance biocompatibility.

Evaluation of minimum quantity lubrication grinding with nano-particles and recent related patents.

PubMed

Li, Changhe; Wang, Sheng; Zhang, Qiang; Jia, Dongzhou

2013-06-01

In recent years, a large number of patents have been devoted to developing minimum quantity lubrication (MQL) grinding techniques that can significantly improve both environmentally conscious and energy saving and costeffective sustainable grinding fluid alternatives. Among them, one patent is about a supply system for the grinding fluid in nano-particle jet MQL, which produced MQL lubricant by adding solid nano-particles in degradable grinding fluid. The MQL supply device turns the lubricant to the pulse drops with fixed pressure, unchanged pulse frequency and the same drop diameter. The drops will be produced and injected in the grinding zone in the form of jet flow under high pressure gas and air seal. As people become increasingly demanding on our environment, minimum quantity lubrication has been widely used in the grinding and processing. Yet, it presents the defect of insufficient cooling performance, which confines its development. To improve the heat transfer efficiency of MQL, nano-particles of a certain mass fraction can be added in the minimum quantity of lubricant oil, which concomitantly will improve the lubrication effects in the processing. In this study, the grinding experiment corroborated the effect of nano-particles in surface grinding. In addition, compared with other forms of lubrication, the results presented that the grinding force, the friction coefficient and specific grinding energy of MQL grinding have been significantly weakened, while G ratio greatly rose. These are attributed to the friction oil-film with excellent anti-friction and anti-wear performance, which is generated nano-particles at the wheel/workpiece interface. In this research, the cooling performance of nano-particle jet MQL was analyzed. Based on tests and experiments, the surface temperature was assayed from different methods, including flood lubricating oil, dry grinding, MQL grinding and nano-particle jet MQL grinding. Because of the outstanding heat transfer

Optical fiber dispersion characterization study

NASA Technical Reports Server (NTRS)

Geeslin, A.; Arriad, A.; Riad, S. M.; Padgett, M. E.

1979-01-01

The theory, design, and results of optical fiber pulse dispersion measurements are considered. Both the hardware and software required to perform this type of measurement are described. Hardware includes a thermoelectrically cooled injection laser diode source, an 800 GHz gain bandwidth produce avalanche photodiode and an input mode scrambler. Software for a HP 9825 computer includes fast Fourier transform, inverse Fourier transform, and optimal compensation deconvolution. Test set construction details are also included. Test results include data collected on a 1 Km fiber, a 4 Km fiber, a fused spliced, eight 600 meter length fibers concatenated to form 4.8 Km, and up to nine optical connectors.

Strong, light, multifunctional fibers of carbon nanotubes with ultrahigh conductivity.

PubMed

Behabtu, Natnael; Young, Colin C; Tsentalovich, Dmitri E; Kleinerman, Olga; Wang, Xuan; Ma, Anson W K; Bengio, E Amram; ter Waarbeek, Ron F; de Jong, Jorrit J; Hoogerwerf, Ron E; Fairchild, Steven B; Ferguson, John B; Maruyama, Benji; Kono, Junichiro; Talmon, Yeshayahu; Cohen, Yachin; Otto, Marcin J; Pasquali, Matteo

2013-01-11

Broader applications of carbon nanotubes to real-world problems have largely gone unfulfilled because of difficult material synthesis and laborious processing. We report high-performance multifunctional carbon nanotube (CNT) fibers that combine the specific strength, stiffness, and thermal conductivity of carbon fibers with the specific electrical conductivity of metals. These fibers consist of bulk-grown CNTs and are produced by high-throughput wet spinning, the same process used to produce high-performance industrial fibers. These scalable CNT fibers are positioned for high-value applications, such as aerospace electronics and field emission, and can evolve into engineered materials with broad long-term impact, from consumer electronics to long-range power transmission.

Numerical approach of the injection molding process of fiber-reinforced composite with considering fiber orientation

NASA Astrophysics Data System (ADS)

Nguyen Thi, T. B.; Yokoyama, A.; Ota, K.; Kodama, K.; Yamashita, K.; Isogai, Y.; Furuichi, K.; Nonomura, C.

2014-05-01

One of the most important challenges in the injection molding process of the short-glass fiber/thermoplastic composite parts is being able to predict the fiber orientation, since it controls the mechanical and the physical properties of the final parts. Folgar and Tucker included into the Jeffery equation a diffusive type of term, which introduces a phenomenological coefficient for modeling the randomizing effect of the mechanical interactions between the fibers, to predict the fiber orientation in concentrated suspensions. Their experiments indicated that this coefficient depends on the fiber volume fraction and aspect ratio. However, a definition of the fiber interaction coefficient, which is very necessary in the fiber orientation simulations, hasn't still been proven yet. Consequently, this study proposed a developed fiber interaction model that has been introduced a fiber dynamics simulation in order to obtain a global fiber interaction coefficient. This supposed that the coefficient is a sum function of the fiber concentration, aspect ratio, and angular velocity. The proposed model was incorporated into a computer aided engineering simulation package C-Mold. Short-glass fiber/polyamide-6 composites were produced in the injection molding with the fiber weight concentration of 30 wt.%, 50 wt.%, and 70 wt.%. The physical properties of these composites were examined, and their fiber orientation distributions were measured by micro-computed-tomography equipment μ-CT. The simulation results showed a good agreement with experiment results.

Ethanol extraction of phytosterols from corn fiber

DOEpatents

Abbas, Charles; Beery, Kyle E.; Binder, Thomas P.; Rammelsberg, Anne M.

2010-11-16

The present invention provides a process for extracting sterols from a high solids, thermochemically hydrolyzed corn fiber using ethanol as the extractant. The process includes obtaining a corn fiber slurry having a moisture content from about 20 weight percent to about 50 weight percent solids (high solids content), thermochemically processing the corn fiber slurry having high solids content of 20 to 50% to produce a hydrolyzed corn fiber slurry, dewatering the hydrolyzed corn fiber slurry to achieve a residual corn fiber having a moisture content from about 30 to 80 weight percent solids, washing the residual corn fiber, dewatering the washed, hydrolyzed corn fiber slurry to achieve a residual corn fiber having a moisture content from about 30 to 80 weight percent solids, and extracting the residual corn fiber with ethanol and separating at least one sterol.

Plasmonic graded nano-disks as nano-optical conveyor belt.

PubMed

Kang, Zhiwen; Lu, Haifei; Chen, Jiajie; Chen, Kun; Xu, Fang; Ho, Ho-Pui

2014-08-11

We propose a plasmonic system consisting of nano-disks (NDs) with graded diameters for the realization of nano-optical conveyor belt. The system contains a couple of NDs with individual elements coded with different resonant wavelengths. By sequentially switching the wavelength and polarization of the excitation source, optically trapped target nano-particle can be transferred from one ND to another. The feasibility of such function is verified based on the three-dimensional finite-difference time-domain technique and the Maxwell stress tensor method. Our design may provide an alternative way to construct nano-optical conveyor belt with which target molecules can be delivered between trapping sites, thus enabling many on-chip optofluidic applications.

[Transmission efficiency analysis of near-field fiber probe using FDTD simulation].

PubMed

Huang, Wei; Dai, Song-Tao; Wang, Huai-Yu; Zhou, Yun-Song

2011-10-01

A fiber probe is the key component of near-field optical technology which is widely used in high resolution imaging, spectroscopy detection and nano processing. How to improve the transmission efficiency of the fiber probe is a very important problem in the application of near-field optical technology. Based on the results of 3D-FDTD computation, the dependence of the transmission efficiency on the cone angle, the aperture diameter, the wavelength and the thickness of metal cladding is revealed. The authors have also made a comparison between naked probe and the probe with metal cladding in terms of transmission efficiency and spatial resolution. In addition, the authors have discovered the fluctuation phenomena of transmission efficiency as the wavelength of incident laser increases.

The Effect of Nano Loading and Ultrasonic Compounding of EVA/LDPE/Nano-magnesium Hydroxide on Mechanical Properties and Distribution of Nano Particles

NASA Astrophysics Data System (ADS)

Azman, I. A.; Salleh, R. M.; Alauddin, S. M.; Shueb, M. I.

2018-05-01

Blends of Ethylene Vinyl Acetate (EVA) and Low-Density Polyethylene (LDPE) are promising composite which have good mechanical properties to environmental stress cracking. However, they lack fire resistant properties, which limits it usage in wire and cable industry. In order to improve flame retardancy ability, a range of nano-magnesium hydroxide (nano-MH) loading which is from 0 phr to maximum of 20 phr with ultrasonic extrusion 0-100 kHz frequencies have been introduced. Ultrasonic extrusion was used to improve the distribution of nano-MH. It was found that, 10 phr of nano loading with 100 kHz ultrasonic assisted has greater tensile strength compared to the nanocomposite without ultrasonication. Further increase of nano MH loading, will decrease the tensile properties. Better elongation at break was observed at10 phr nano-MH with the frequency of 50 kHz. The sample of 20 phr of nanoMH assisted with 50 kHz ultrasonic exhibits good flexural properties while 10 phr of nano-MH without the ultrasonic assisted demonstrates good in izod impact properties. From the evaluation of mechanical properties studied, it was found that 10 phr of nano-MH has shown the best performance among all the samples tested for EVA/LDPE/nano-MH composites. Transmission Electron Microscopy (TEM) has been conducted on 10 phr sample with different frequencies in order to observe the distribution of nano-MH particles. The sample with 100 kHz frequency shows more uniform dispersion of nano-MH in EVA/LDPE composites. This investigation indicates that the ultrasonic technology can enhance the mechanical properties studied as well as the dispersion of nano particles in the composite.

Contraction produced by intracellular injection of calcium, strontium, and barium in the single crayfish muscle fibers.

PubMed

Matsumura, M; Mashima, H

1976-01-01

Ca ions were ionophoretically injected through an intracellular microelectrode into the single muscle fiber of a crayfish, and the resulting contraction sphere was observed under a microscope and photographed with a movie camera. The minimum contraction produced by the threshold current involved usually three or four, sometimes two, sarcomers on both sides of the injecting pipette but contraction involving only one sarcomere was not observered. The rheobase of the Ca-injecting current was 3.2 X 10(-9) A. The strength-duration curves were determined for Ca-, Sr-, and Ba-injecting currents; all fitted a similar hyperbolic equation. The threshold amount of Ca above rheobasic injection was 2.1 X 10(-15)mol, and the ratios between threshold amounts were Ca: Sr: Ba=1: 1.9: 3.0. The effects of Ca and Sr were additive for the contraction. More current was required for the Ca-injection to produce the contraction in the K-depolarized-or 15mM-procaine-treated muscle, although less current was sufficient for the muscle treated with 0.5-1.0 mM of caffeine. The participation of the Ca-induced Ca release mechanism in the contraction produced by Ca injection and the role of Sr or Ba as a substitute for Ca were discussed.

Preform For Producing An Optical Fiber And Method Therefor

DOEpatents

Kliner, Dahv A. V.; Koplow, Jeffery P.

2004-08-10

The present invention provides a simple method for fabricating fiber-optic glass preforms having complex refractive index configurations and/or dopant distributions in a radial direction with a high degree of accuracy and precision. The method teaches bundling together a plurality of glass rods of specific physical, chemical, or optical properties and wherein the rod bundle is fused in a manner that maintains the cross-sectional composition and refractive-index profiles established by the position of the rods.

Preform For Producing An Optical Fiber And Method Therefor

DOEpatents

Kliner, Dahv A. V.; Koplow, Jeffery P.

2005-04-19

The present invention provides a simple method for fabricating fiber-optic glass preforms having complex refractive index configurations and/or dopant distributions in a radial direction with a high degree of accuracy and precision. The method teaches bundling together a plurality of glass rods of specific physical, chemical, or optical properties and wherein the rod bundle is fused in a manner that maintains the cross-sectional composition and refractive-index profiles established by the position of the rods.

Process for electrospinning chitin fibers from chitinous biomass solution

DOEpatents

Swatloski, Richard P.; Barber, Patrick S.; Opichka, Terrance; Bonner, Jonathan R.; Gurau, Gabriela; Griggs, Christopher Scott; Rogers, Robin D.

2017-06-20

Disclosed are methods for electrospinning chitinous biomass solution to form chitin fibers, using ionic liquids or other ion-containing liquids as solvent. Chitin fibers produced thereby and articles containing such chitin fibers are also disclosed. The chitin fiber thus obtained has very high surface area and improved strength over currently commercially available chitin materials.

Oscillation-based methods for actuation and manipulation of nano-objects

NASA Astrophysics Data System (ADS)

Popov, V. L.

2017-09-01

We discuss how oscillations can be used for fixation or manipulation of nano-objects or producing nano-drives. The underlying principles are scale-invariant and principally can be scaled down up to the molecular scale. The main underlying principle of fixation and actuation occurs to be symmetry breaking of an oscillating system. From this unifying standpoint, a series of actuation principles are discussed as dragging, ratchets, micro walking, friction-inertia actuators, oscillation tweezers, flagella motors for propulsion in liquids as well as some recently proposed actuation principles.

Characterization of Silk/Poly 3-Hydroxybutyrate-chitosan-multi-walled Carbon Nanotube Micro-nano Scaffold: A New Hybrid Scaffold for Tissue Engineering Applications.

PubMed

Mirmusavi, Mohammad Hossein; Karbasi, Saeed; Semnani, Dariush; Kharazi, Anousheh Zargar

2018-01-01

Long-term healing tissue engineering scaffolds must hold its full mechanical strength at least for 12 weeks. Nano-micro scaffolds consist of electrospinning nanofibers and textile microfibers to support cell behavior and mechanical strength, respectively. The new nano-micro hybrid scaffold was fabricated by electrospinning poly 3-hydroxybutyrate-chitosan-multi-walled carbon nanotube (MWNT functionalized by COOH) solution on knitted silk in a random manner with different amounts of MWNT. The physical, mechanical, and biodegradation properties were assessed through scanning electron microscopy, Fourier-transform infrared (FTIR) spectroscopy, water contact angle test, tensile strength test, and weight loss test. The scaffold without MWNT was chosen as control sample. An increase in the amount of MWNT up to 1 wt% leads to better fiber diameter distribution, more hydrophilicity, biodegradation rate, and higher tensile strength in comparison with other samples. The porosity percentage of all scaffolds is more than 80%. According to FTIR spectra, the nanofibrous coat on knitted silk did not have any effect on silk fibroin crystallinity structures, and according to tensile strength test, the coat had a significant effect on tensile strength in comparison with pure knitted silk ( P ≤ 0.05). The average fiber diameter decreased due to an increase in electrical conductivity of the solution and fiber stretch in electrical field due to MWNTs. The scaffold containing 1 wt% MWNT was more hydrophilic due to the presence of many COOH groups of functionalized MWNT, thus an increase in the hydrolysis and degradation rate of this sample. High intrinsic tensile strength of MWNTs and improvement of nano-micro interface connection lead to an increase in tensile strength in scaffolds containing MWNT.

Characterization of Silk/Poly 3-Hydroxybutyrate-chitosan-multi-walled Carbon Nanotube Micro-nano Scaffold: A New Hybrid Scaffold for Tissue Engineering Applications

PubMed Central

Mirmusavi, Mohammad Hossein; Karbasi, Saeed; Semnani, Dariush; Kharazi, Anousheh Zargar

2018-01-01

Background: Long-term healing tissue engineering scaffolds must hold its full mechanical strength at least for 12 weeks. Nano-micro scaffolds consist of electrospinning nanofibers and textile microfibers to support cell behavior and mechanical strength, respectively. Methods: The new nano-micro hybrid scaffold was fabricated by electrospinning poly 3-hydroxybutyrate-chitosan-multi-walled carbon nanotube (MWNT functionalized by COOH) solution on knitted silk in a random manner with different amounts of MWNT. The physical, mechanical, and biodegradation properties were assessed through scanning electron microscopy, Fourier-transform infrared (FTIR) spectroscopy, water contact angle test, tensile strength test, and weight loss test. The scaffold without MWNT was chosen as control sample. Results: An increase in the amount of MWNT up to 1 wt% leads to better fiber diameter distribution, more hydrophilicity, biodegradation rate, and higher tensile strength in comparison with other samples. The porosity percentage of all scaffolds is more than 80%. According to FTIR spectra, the nanofibrous coat on knitted silk did not have any effect on silk fibroin crystallinity structures, and according to tensile strength test, the coat had a significant effect on tensile strength in comparison with pure knitted silk (P ≤ 0.05). The average fiber diameter decreased due to an increase in electrical conductivity of the solution and fiber stretch in electrical field due to MWNTs. The scaffold containing 1 wt% MWNT was more hydrophilic due to the presence of many COOH groups of functionalized MWNT, thus an increase in the hydrolysis and degradation rate of this sample. Conclusions: High intrinsic tensile strength of MWNTs and improvement of nano-micro interface connection lead to an increase in tensile strength in scaffolds containing MWNT. PMID:29535924

Chiral fiber sensors

NASA Astrophysics Data System (ADS)

Kopp, Victor I.; Churikov, Victor M.; Singer, Jonathan; Neugroschl, Daniel; Genack, Azriel Z.

2010-04-01

We have fabricated a variety of chiral fiber sensors by twisting one or more standard or custom optical fibers with noncircular or nonconcentric core as they pass though a miniature oven. The resulting structures are as stable as the glass material and can be produced with helical pitch ranging from microns to hundreds of microns. The polarization selectivity of the chiral gratings is determined by the geometry of the fiber cross section. Single helix structures are polarization insensitive, while double helix gratings interact only with a single optical polarization component. Both single and double helix gratings may function as a fiber long period grating, coupling core and cladding modes or as a diffraction grating scattering light from the fiber core out of the fiber. The resulting dips in the transmission spectrum are sensitive to fiber elongation, twist and temperature, and (in the case of the long period gratings) to the refractive index of the surrounding medium. The suitability of chiral gratings for sensing temperature, elongation, twist and liquid levels will be discussed. Gratings made of radiation sensitive glass can be used to measure the cumulative radiation dose, while gratings made of radiation-hardened glass are suitable for stable sensing of the environment in nuclear power plants. Excellent temperature stability up to 900°C is found in pure silica chiral diffraction grating sensors.

Improvements of nano-SiO2 on sludge/fly ash mortar.

PubMed

Lin, D F; Lin, K L; Chang, W C; Luo, H L; Cai, M Q

2008-01-01

Sewage sludge ash has been widely applied to cementitious materials. In this study, in order to determine effects of nano-SiO(2) additives on properties of sludge/fly ash mortar, different amounts of nano-SiO(2) were added to sludge/fly ash mortar specimens to investigate their physical properties and micro-structures. A water-binding ratio of 0.7 was assigned to the mix. Substitution amounts of 0%, 10%, 20%, and 30% of sludge/fly ash (1:1 ratio) were proposed. Moreover, 0%, 1%, 2%, and 3% of nano-SiO(2) was added to the mix. Tests, including SEM and compressive strength, were carried out on mortar specimens cured at 3, 7, and 28 days. Results showed that sludge/fly ash can make the crystals of cement hydration product finer. Moreover, crystals increased after nano-SiO(2) was added. Hence, nano-SiO(2) can improve the effects of sludge/fly ash on the hydration of mortar. Further, due to the low pozzolanic reaction active index of sludge ash, early compressive strengths of sludge/fly ash mortar were decreased. Yet, nano-SiO(2) could help produce hydration crystals, which implies that the addition of nano-SiO(2) to mortar can improve the influence of sludge/fly ash on the development of the early strength of the mortar.

Multifunctional hydrogel nano-probes for atomic force microscopy

PubMed Central

Lee, Jae Seol; Song, Jungki; Kim, Seong Oh; Kim, Seokbeom; Lee, Wooju; Jackman, Joshua A.; Kim, Dongchoul; Cho, Nam-Joon; Lee, Jungchul

2016-01-01

Since the invention of the atomic force microscope (AFM) three decades ago, there have been numerous advances in its measurement capabilities. Curiously, throughout these developments, the fundamental nature of the force-sensing probe—the key actuating element—has remained largely unchanged. It is produced by long-established microfabrication etching strategies and typically composed of silicon-based materials. Here, we report a new class of photopolymerizable hydrogel nano-probes that are produced by bottom-up fabrication with compressible replica moulding. The hydrogel probes demonstrate excellent capabilities for AFM imaging and force measurement applications while enabling programmable, multifunctional capabilities based on compositionally adjustable mechanical properties and facile encapsulation of various nanomaterials. Taken together, the simple, fast and affordable manufacturing route and multifunctional capabilities of hydrogel AFM nano-probes highlight the potential of soft matter mechanical transducers in nanotechnology applications. The fabrication scheme can also be readily utilized to prepare hydrogel cantilevers, including in parallel arrays, for nanomechanical sensor devices. PMID:27199165

Preparation and Adsorption Property of Imido-acetic Acid Type Chelating Nano-fibers by Electro-spinning Technique

NASA Astrophysics Data System (ADS)

Yang, Jiali; Lu, Lansi; Zhang, Zhu; Liao, Minhui; He, Huirong; Li, Lingxing; Chen, Jida; Chen, Shijin

2017-12-01

A novel nano-fibrous adsorbent from imino-acetic acid (IDA) and polyvinyl alcohol (PVA) mixture solution was prepared by electro-spinning technique. The nano-fibrous adsorbents with imino-acetic acid functional groups were characterized and demonstrated by fourier transform infrared spectrometry (FT-IR) and the scanning electron microscopy (SEM). The effect of the adsorbents to remove heavy metals such as lead (Pb) and copper (Cu) ions from the aqueous solution was studied. The maximum adsorption percentage (SP) of the metal ions can reach 93.08% for Cu (II) and 96.69% for Pb(II), respectively. Furthermore, it shows that the adsorption procedure of the adsorbents is spontaneous and endothermic, and adsorption rate fits well with pseudo-second-order kinetic model. Most importantly, the reusability of the nanofibers for removal of metal ions was also demonstrated to be used at least five times.

Mussel-inspired nano-building block assemblies for mimicking extracellular matrix microenvironments with multiple functions.

PubMed

Wang, Zhenming; Jia, Zhanrong; Jiang, Yanan; Li, Pengfei; Han, Lu; Lu, Xiong; Ren, Fuzeng; Wang, Kefeng; Yuan, Huiping

2017-08-03

The assembly of nano-building blocks is an effective way to produce artificial extracellular matrix microenvironments with hierarchical micro/nano structures. However, it is hard to assemble different types of nano-building blocks, to form composite coatings with multiple functions, by traditional layer-by-layer (LbL) self-assembly methods. Inspired by the mussel adhesion mechanism, we developed polydopamine (PDA)-decorated bovine serum albumin microspheres (BSA-MS) and nano-hydroxyapatite (nano-HA), and assembled them to form bioactive coatings with micro/nano structures encapsulating bone morphogenetic protein-2 (BMP-2). First, PDA-decorated nano-HA (nano-pHA) was obtained by oxidative polymerization of dopamine on nano-HA. Second, BMP-2-encapsulated BSA microspheres were prepared through desolvation, and then were also decorated by PDA (pBSA-MS). Finally, the nano-pHA and pBSA-MS were assembled using the adhesive properties of PDA. Bone marrow stromal cell cultures and in vivo implantation, showed that the pHA/pBSA (BMP-2) coatings can promote cell adhesion, proliferation, and benefited for osteoinductivity. PDA decoration was also applied to assemble various functional nanoparticles, such as nano-HA, polystyrene, and Fe 3 O 4 nanoparticles. In summary, this study provides a novel strategy for the assembly of biofunctional nano-building blocks, which surpasses traditional LbL self-assembly of polyelectrolytes, and can find broad applications in bioactive agents delivery or multi-functional coatings.

Using DNA-labelled nano- and microparticles to track particle transport in the environment

NASA Astrophysics Data System (ADS)

McNew, Coy; Wang, Chaozi; Dahlke, Helen; Lyon, Steve; Walter, Todd

2017-04-01

By utilizing bio-molecular nanotechnology developed for nano-medicines and drug delivery, we are able to produce DNA-labelled nano- and microparticle tracers for use in a myriad of environmental systems. The use of custom sequenced DNA allows for the fabrication of an enormous number of uniquely labelled tracers with identical transport properties (approximately 1.61 x 1060 unique sequences), each independently quantifiable, that can be applied simultaneously in any hydrologic system. By controlling the fabrication procedure to produce particles of custom size and charge, we are able to tag each size-charge combination uniquely in order to directly probe the effect of these variables on the transport properties of the particles. Here we present our methods for fabrication, extraction, and analysis of the DNA nano- and microparticle tracers, along with results from several successful applications of the tracers, including transport and retention analysis at the lab, continuum, and field scales. To date, our DNA-labelled nano- and microparticle tracers have proved useful in surface and subsurface water applications, soil retention, and even subglacial flow pathways. The range of potential applications continue to prove nearly limitless.

A recipe to create nano-grains on dolomite

NASA Astrophysics Data System (ADS)

Røyne, Anja; Pluymakers, Anne

2017-04-01

Advances in imaging techniques in recent years have allowed for easy microstructure visualization at nano-resolution, and many studies have observed nano-grains in different materials, including rocks. An important example in geological systems is their seemingly ubiquitous occurrence on so-called mirror-like slip surfaces, produced in natural and experimental earthquakes of both carbonate and silicate rocks. It is, however, not yet clear whether these nano-grains can indeed be used as a reliable indicator of seismic slip. Since carbonates are prone to decarbonation at temperatures exceeding 550 - 600 °C, nano-grain formation may be formed due to heating rather than shear. In this study, we have investigated the effect of elevated temperatures on carbonate fault rocks. We used hand-polished mirror-like dolomite protolith, as well as natural fault mirror surfaces, obtained from the Foiana Fault Zone from the Southern Alps in Italy. The samples were heated to 200 to 800 degC in a 5 hour heating cycle, followed by slow cooling ( 12 h) to room temperature. Subsequently, we imaged the samples using SEM and AFM. Nano-grain formation on the surfaces of hand-polished samples starts around 400 ° C, and is pervasive at and above 600 ° C. Fault mirror samples are initially coated with naturally formed nano-grains and only very local patches on these surfaces display obvious morphological changes due to heating. Exposing both types of sample heated to 600 °C to DI water under the AFM shows rapid recrystallization and the formation of a more porous and blade-like crystal layer on the entire surface. This happens both in hand-polished and naturally polished surfaces. Fault mirror samples that have not been heated do not change when exposed to water. We have shown that nano-grains can form as a result of heating without shear, but that samples that have experienced high shear strain have a water- and heat-resistant coating composed of otherwise morphologically

Development of Ceramic Fibers for Reinforcement in Composite Materials

NASA Technical Reports Server (NTRS)

Gates, L. E.; Lent, W. E.; Teague, W. T.

1961-01-01

Refinements of the vertical arc fiberizing apparatus resulted in its ability to fiberize very different refractory glasses having wide ranges of properties. Although the apparatus, was originally designed as a laboratory research tool for the evaluation of many compositions daily, up to one quarter pound of fibers of a single composition could be produced in an 8-hour day. Fibers up to six and a half feet long were produced with the apparatus. Studies were conducted of two methods of fiberizing refractory glasses requiring rapid freezing from the melt. The first method consisted of fiberizing droplets of molten glass passing through an annular nozzle. The second method consisted of reconstructing the annular nozzle in. the shape of a horseshoe to achieve a shorter delay in blasting a molten droplet from the tip of a rod. Both methods were judged feasible for producing fibers of glasses requiring rapid freezing. The first method would be more amenable to volume fiber production. Studies of induction heating for fiber formation did not lead to its designation as a very efficient heating method. Problems. remain to be solved, in the design of a suitable susceptor for a higher heating rate, in protecting the susceptor from oxidation with an inert gas, in contamination of the melt from a refractory crucible, and in the protective radiation shielding of the induction concentrator coil. It is not considered practical to continue studies of this heating method. In the course of this program 151 refractory glass compositions were evaluated for fiber, forming characteristics. Of the various types of materials studied, the following showed promise in producing acceptable refractory fibers: sIlica- spinel (magnesium aluminate), silica- spinel-zirconia, silica-zirconia, silica-zinc spinel, aluminum phosphate glasses, and fluoride glasses. Compositions which did not produce acceptable fibers were high zirconia materials, barium spinels, and calcium aluminates. Improvements in

On hydrophilicity improvement of the porous anodic alumina film by hybrid nano/micro structuring

NASA Astrophysics Data System (ADS)

Wang, Weichao; Zhao, Wei; Wang, Kaige; Wang, Lei; Wang, Xuewen; Wang, Shuang; Zhang, Chen; Bai, Jintao

2017-09-01

In both, laboratory and industry, tremendous attention is paid to discover an effective technique to produce uniform, controllable and (super) hydrophilic surfaces over large areas that are useful in a wide range of applications. In this investigation, by combing porous anodic alumina (PAA) film with nano-structures and microarray of aluminum, the hydrophilicity of hybrid nano-micro structure has been significantly improved. It is found some factors can affect the hydrophilicity of film, such as the size and aspect ratio of microarray, the thickness of nano-PAA film etc. Comparing with pure nano-PAA films and microarray, the hybrid nano-micro structure can provide uniform surface with significantly better hydrophilicity. The improvement can be up to 84%. Also, this technique exhibits good stability and repeatability for industrial production. By optimizing the thickness of nano-PAA film and aspect ratio of micro-structures, super-hydrophilicity can be reached. This study has obvious prospect in the fields of chemical industry, biomedical engineering and lab-on-a-chip applications.

High Carbohydrate-Fiber Nutrition for Running and Health.

ERIC Educational Resources Information Center

Battinelli, Thomas

1983-01-01

The roles of carbohydrates, fats, proteins, and fiber in producing energy for health and exercise are discussed. Long-distance runners should have a high intake of complex carbohydrates and fiber. (PP)

A subunit vaccine against the adenovirus egg-drop syndrome using part of its fiber protein.

PubMed

Fingerut, E; Gutter, B; Gallili, G; Michael, A; Pitcovski, J

2003-06-20

In this study, the effectiveness of antibodies against the hexon, fiber or a fiber fragment of an avian adenovirus egg-drop syndrome (EDS), in neutralizing the virus was tested. The fiber protein is responsible for binding the virus to the target cell. The fiber fragment knob-s comprises the carboxy-terminal knob domain and 34 amino acids of the immediately adjacent shaft domain of the adenovirus fiber protein. The hexon, fiber capsid protein and knob-s were produced in E. coli and injected into chickens. Antibodies that were produced against the whole fiber protein showed some hemagglutination inhibition (HI) activity. Antibodies produced against the knob-s protein showed HI activity and serum neutralization (SN) activity similar to the positive control-whole virus vaccine. We assume that production of only part of the fiber enables the protein produced in E. coli to fold correctly. Antibodies produced against the hexon protein showed no SN activity. In summary, knob-s induced SN and HI antibodies against EDS virus at a rate similar to the whole virus and were significantly more efficient than the full-length fiber. The recombinant knob-s protein may be used as a vaccine against pathogenic adenovirus infections.

Optical Fiber Protection

NASA Technical Reports Server (NTRS)

1999-01-01

F&S Inc. developed and commercialized fiber optic and microelectromechanical systems- (MEMS) based instrumentation for harsh environments encountered in the aerospace industry. The NASA SBIR programs have provided F&S the funds and the technology to develop ruggedized coatings and coating techniques that are applied during the optical fiber draw process. The F&S optical fiber fabrication facility and developed coating methods enable F&S to manufacture specialty optical fiber with custom designed refractive index profiles and protective or active coatings. F&S has demonstrated sputtered coatings using metals and ceramics and combinations of each, and has also developed techniques to apply thin coatings of specialized polyimides formulated at NASA Langley Research Center. With these capabilities, F&S has produced cost-effective, reliable instrumentation and sensors capable of withstanding temperatures up to 800? C and continues building commercial sales with corporate partners and private funding. More recently, F&S has adapted the same sensing platforms to provide the rapid detection and identification of chemical and biological agents

Numerical approach of the injection molding process of fiber-reinforced composite with considering fiber orientation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nguyen Thi, T. B., E-mail: thanhbinh.skku@gmail.com, E-mail: yokoyama@kit.ac.jp; Yokoyama, A., E-mail: thanhbinh.skku@gmail.com, E-mail: yokoyama@kit.ac.jp; Ota, K., E-mail: kei-ota@toyobo.jp, E-mail: katsuhiro-kodama@toyobo.jp, E-mail: katsuhisa-yamashita@toyobo.jp, E-mail: yumiko-isogai@toyobo.jp, E-mail: kenji-furuichi@toyobo.jp, E-mail: chisato-nonomura@toyobo.jp

2014-05-15

One of the most important challenges in the injection molding process of the short-glass fiber/thermoplastic composite parts is being able to predict the fiber orientation, since it controls the mechanical and the physical properties of the final parts. Folgar and Tucker included into the Jeffery equation a diffusive type of term, which introduces a phenomenological coefficient for modeling the randomizing effect of the mechanical interactions between the fibers, to predict the fiber orientation in concentrated suspensions. Their experiments indicated that this coefficient depends on the fiber volume fraction and aspect ratio. However, a definition of the fiber interaction coefficient, whichmore » is very necessary in the fiber orientation simulations, hasn't still been proven yet. Consequently, this study proposed a developed fiber interaction model that has been introduced a fiber dynamics simulation in order to obtain a global fiber interaction coefficient. This supposed that the coefficient is a sum function of the fiber concentration, aspect ratio, and angular velocity. The proposed model was incorporated into a computer aided engineering simulation package C-Mold. Short-glass fiber/polyamide-6 composites were produced in the injection molding with the fiber weight concentration of 30 wt.%, 50 wt.%, and 70 wt.%. The physical properties of these composites were examined, and their fiber orientation distributions were measured by micro-computed-tomography equipment μ-CT. The simulation results showed a good agreement with experiment results.« less

Tm:germanate Fiber Laser: Tuning And Q-switching

NASA Technical Reports Server (NTRS)

Barnes, Norman P.; Walsh, Brian M.; Reichle, Donald J.; DeYoung, R. J.; Jiang, Shibin

2007-01-01

A Tm:germanate fiber laser produced >0.25 mJ/pulse in a 45 ns pulse. It is capable of producing multiple Q-switched pulses from a single p ump pulse. With the addition of a diffraction grating, Tm:germanate f iber lasers produced a wide, but length dependent, tuning range. By s electing the fiber length, the tuning range extends from 1.88 to 2.04 ?m. These traits make Tm:germanate lasers suitable for remote sensin g of water vapor.

Comparative study on the mechanical and microstructural characterisation of AA 7075 nano and hybrid nanocomposites produced by stir and squeeze casting.

PubMed

Kannan, C; Ramanujam, R

2017-07-01

In this research work, a comparative evaluation on the mechanical and microstructural characteristics of aluminium based single and hybrid reinforced nanocomposites was carried out. The manufacture of a single reinforced nanocomposite was conducted with the distribution of 2 wt.% nano alumina particles (avg. particle size 30-50 nm) in the molten aluminium alloy of grade AA 7075; while the hybrid reinforced nanocomposites were produced with of 4 wt.% silicon carbide (avg. particle size 5-10 µm) and 2 wt.%, 4 wt.% nano alumina particles. Three numbers of single reinforced nanocomposites were manufactured through stir casting with reinforcements preheated to different temperatures viz. 400 °C, 500 °C, and 600 °C. The stir cast procedure was extended to fabricate two hybrid reinforced nanocomposites with reinforcements preheated to 500 °C prior to their inclusion. A single reinforced nanocomposite was also developed by squeeze casting with a pressure of 101 MPa. Mechanical and physical properties such as density, hardness, ultimate tensile strength, and impact strength were evaluated on all the developed composites. The microstructural observation was carried out using optical and scanning electron microscopy. On comparison with base alloy, an improvement of 63.7% and 81.1% in brinell hardness was observed for single and hybrid reinforced nanocomposites respectively. About 16% higher ultimate tensile strength was noticed with the squeeze cast single reinforced nanocomposite over the stir cast.

Process of Making Boron-Fiber Reinforced Composite Tape

NASA Technical Reports Server (NTRS)

Belvin, Harry L. (Inventor); Cano, Roberto J. (Inventor); Johnston, Norman J. (Inventor); Marchello, Joseph M. (Inventor)

2002-01-01

The invention is an apparatus and method for producing a hybrid boron reinforced polymer matrix composition from powder pre-impregnated fiber tow bundles and a linear array of boron fibers. The boron fibers are applied onto the powder pre-impregnated fiber tow bundles and then are processed within a processing component having an impregnation bar assembly. After passing through variable-dimension forming nip-rollers, the powder pre-impregnated fiber tow bundles with the boron fibers become a hybrid boron reinforced polymer matrix composite tape. A driving mechanism pulls the powder pre-impregnated fiber tow bundles with boron fibers through the processing line of the apparatus and a take-up spool collects the formed hybrid boron-fiber reinforced polymer matrix composite tape.

Switchable and responsive liquid crystal-functionalized microfibers produced via coaxial electrospinning

NASA Astrophysics Data System (ADS)

Lagerwall, Jan P. F.

2012-03-01

"Wearable technology" or "smart textiles" are concepts that are very rapidly gaining in attention around the world, as industry as well as academia are making major advances in integrating advanced devices with various textiles around our household. The technological challenges involved in this development are however considerable, calling for new solutions, new materials and truly original thinking. An attractive approach to realize certain classes of wearable devices may be to use textile fibers functionalized by responsive materials such as liquid crystals, normally not connected to textiles. We can produce non-woven textiles with such fibers by means of electrospinning, a technique for producing very thin polymer fibers that can be uniform or with core-sheath geometries. Since the core can be made out of traditionally non-spinnable materials we can use coaxial electrospinning (one fluid spun inside another) to produce composite fibers with a core of liquid crystal inside a polymer sheath. The resulting fibers constitute an entirely new configuration for applying liquid crystals, giving the fibers functionality and responsiveness. For instance, with a cholesteric core we can produce non-woven mats with iridescent color that can be tuned (or removed) e.g. by heating or cooling. In this paper I describe our method of producing these novel functionalized fibers and their characterization, and I will discuss the directions for future research and application possibilities, e.g. in clothing-integrated sensors and indicators.

Aerobic and anaerobic biosynthesis of nano-selenium for remediation of mercury contaminated soil.

PubMed

Wang, Xiaonan; Zhang, Daoyong; Pan, Xiangliang; Lee, Duu-Jong; Al-Misned, Fahad A; Mortuza, M Golam; Gadd, Geoffrey Michael

2017-03-01

Selenium (Se) nanoparticles are often synthesized by anaerobes. However, anaerobic bacteria cannot be directly applied for bioremediation of contaminated top soil which is generally aerobic. In this study, a selenite-reducing bacterium, Citrobacter freundii Y9, demonstrated high selenite reducing power and produced elemental nano-selenium nanoparticles (nano-Se 0 ) under both aerobic and anaerobic conditions. The biogenic nano-Se 0 converted 45.8-57.1% and 39.1-48.6% of elemental mercury (Hg 0 ) in the contaminated soil to insoluble mercuric selenide (HgSe) under anaerobic and aerobic conditions, respectively. Addition of sodium dodecyl sulfonate enhanced Hg 0 remediation, probably owing to the release of intracellular nano-Se 0 from the bacterial cells for Hg fixation. The reaction product after remediation was identified as non-reactive HgSe that was formed by amalgamation of nano-Se 0 and Hg 0 . Biosynthesis of nano-Se 0 both aerobically and anaerobically therefore provides a versatile and cost-effective remediation approach for Hg 0 -contaminated surface and subsurface soils, where the redox potential often changes dramatically. Copyright © 2016. Published by Elsevier Ltd.

Dynamic mechanical analysis and high strain-rate energy absorption characteristics of vertically aligned carbon nanotube reinforced woven fiber-glass composites

USDA-ARS?s Scientific Manuscript database

The dynamic mechanical behavior and energy absorption characteristics of nano-enhanced functionally graded composites, consisting of 3 layers of vertically aligned carbon nanotube (VACNT) forests grown on woven fiber-glass (FG) layer and embedded within 10 layers of woven FG, with polyester (PE) and...

Nano-extrusion: a promising tool for continuous manufacturing of solid nano-formulations.

PubMed

Baumgartner, Ramona; Eitzlmayr, Andreas; Matsko, Nadejda; Tetyczka, Carolin; Khinast, Johannes; Roblegg, Eva

2014-12-30

Since more than 40% of today's drugs have low stability, poor solubility and/or limited ability to cross certain biological barriers, new platform technologies are required to address these challenges. This paper describes a novel continuous process that converts a stabilized aqueous nano-suspension into a solid oral formulation in a single step (i.e., the NANEX process) in order to improve the solubility of a model drug (phenytoin). Phenytoin nano-suspensions were prepared via media milling using different stabilizers. A stable nano-suspension was obtained using Tween(®) 80 as a stabilizer. The matrix material (Soluplus(®)) was gravimetrically fed into the hot melt extruder. The suspension was introduced through a side feeding device and mixed with the molten polymer to immediately devolatilize the water in the nano-suspension. Phenytoin nano-crystals were dispersed and embedded in the molten polymer. Investigation of the nano-extrudates via transmission electron microscopy and atomic force microscopy showed that the nano-crystals were embedded de-aggregated in the extrudates. Furthermore, no changes in the crystallinity (due to the mechanical and thermal stress) occurred. The dissolution studies confirmed that the prepared nano-extrudates increased the solubility of nano-crystalline phenytoin, regardless of the polymer. Our work demonstrates that NANEX represents a promising new platform technology in the design of novel drug delivery systems to improve drug performance. Copyright © 2014 Elsevier B.V. All rights reserved.

Tensile Properties and Deflection Temperature of Polypropylene/Sumberejo Kenaf Fiber Composites with Fiber Content Variation

NASA Astrophysics Data System (ADS)

Ollivia, S. L.; Juwono, A. L.; Roseno, Seto

2017-05-01

The use of synthetic fibers as reinforcement in composites has disadvantage which are unsustainable and an adverse impact on the environment. An alternative reinforcement for composites is natural fiber. Polypropylene and Sumberejo kenaf fibers were used respectively as the matrix and reinforcement. The aim of this research was to obtain the optimum tensile properties and deflection temperature with the variation of kenaf fiber fractions. Polypropylene/kenaf fiber composites were fabricated by hot press method. The kenaf fiber was soaked in NaOH solution before being used as the reinforcement and polypropylene was extruded before being used as the matrix. The weight fractions were varied to produce composites and pristine polypropylene samples were also prepared for comparison. The optimum tensile strength, modulus and deflection temperature were found in the composites with the 40 wt% kenaf fiber fraction with an increase up to 80% and 170% compared to the pristine polypropylene with the values of (60.3 ± 4,3) MPa and (159.1 ± 1,8) °C respectively. The Scanning Electron Microscope observation results in the fracture surface of the composites with the 40 wt% fiber fraction showed a relatively good bonding interface between fibers and the matrix and the failure modes were fiber breakage and matrix failures.

Laser fiber cleaving techniques: effects on tip morphology and power output.

PubMed

Vassantachart, Janna M; Lightfoot, Michelle; Yeo, Alexander; Maldonado, Jonathan; Li, Roger; Alsyouf, Muhannad; Martin, Jacob; Lee, Michael; Olgin, Gaudencio; Baldwin, D Duane

2015-01-01

Proper cleaving of reusable laser fibers is needed to maintain optimal functionality. This study quantifies the effect of different cleaving tools on power output of the holmium laser fiber and demonstrates morphologic changes using microscopy. The uncleaved tips of new 272 μm reusable laser fibers were used to obtain baseline power transmission values at 3 W (0.6 J, 5 Hz). Power output for each of four cleaving techniques-11-blade scalpel, scribe pen cleaving tool, diamond cleaving wheel, and suture scissors-was measured in a single-blinded fashion. Dispersion of light from the fibers was compared with manufacturer specifications and rated as "ideal," "acceptable," or "unacceptable" by blinded reviewers. The fiber tips were also imaged using confocal and scanning electron microscopy. Independent samples Kruskal-Wallis test and chi square were used for statistical analysis (α<0.05). New uncleaved fiber tips transmitted 3.04 W of power and were used as a reference (100%). The scribe pen cleaving tool produced the next highest output (97.1%), followed by the scalpel (83.4%), diamond cleaving wheel (77.1%), and suture scissors (61.7%), a trend that was highly significant (P<0.001). On pairwise comparison, no difference in power output was seen between the uncleaved fiber tips and those cleaved with the scribe pen (P=1.0). The rating of the light dispersion patterns from the different cleaving methods followed the same trend as the power output results (P<0.001). Microscopy showed that the scribe pen produced small defects along the fiber cladding but maintained a smooth, flat core surface. The other cleaving techniques produced defects on both the core and cladding. Cleaving techniques produce a significant effect on the initial power transmitted by reusable laser fibers. The scribe pen cleaving tool produced the most consistent and highest average power output.

Strong emission from nano-iron using laser-induced breakdown spectroscopy technique

NASA Astrophysics Data System (ADS)

Rashid, F. F.; ELSherbini, A. M.; Al-Muhamady, A.

2014-06-01

In this paper, we report a strong enhanced emission from laser produced plasma in air from iron oxide nano-material in comparison with the corresponding bulk samples. The enhancement strength differs with different Nd:YAG laser harmonics wavelengths. The analysis showed that such enhancement increased exponentially with the plasma evolution time, while it declines as the laser fluence increased. Experimental data analysis clearly showed that the observed enhancement is mainly associated with the change in the plasma electron density. We claim that this strong enhanced optical emission from laser produced plasma is due to the surface plasmon resonant excitation preferably on nano-oxide materials. Such experimental findings could improve the laser-induced breakdown spectroscopy sensitivity down to extremely low concentrations.

Thermomechanical Characterization of SiC Fiber Tows and Implications for CMC

NASA Technical Reports Server (NTRS)

Yun, H. M.; DiCarlo, J. A.

1999-01-01

In order to better understand SiC fiber behavior within CMC microstructures, mechanical tests were performed on multifilament tows consisting of different types of as produced and pretreated fibers. Tensile strengths of tows and single fibers were measured at room temperature for nonstoichiometric Hi-Nicalon and ZMI fibers and for stoichiometric Hi-Nicalon-S, Tyranno SA. and Sylramic fibers. Based on simple bundle theory, measured strengths for as-produced and sized tows were in general agreement with the single fiber results. However, after sizing removal under inert conditions, tow strengths for the coarser grained stoichiometric fibers were typically lower than those predicted from individual fiber data. This effect is attributed to enhanced fiber-fiber mechanical interaction caused by sizing removal from the rough surfaces of these fibers. In support of this, tow strengths remained high for those fiber types with fine grains or excess surface carbon; and, when re-coated with a BN interphase coating, tow strengths for the coarser grained fibers returned to their as-produced values. When the tows were pretreated in air at intermediate temperatures, tow strengths decreased in a manner that could be correlated with the oxidation characteristics of each fiber type as measured by thermogravimetric analysis. The creep and rupture properties of Hi-Nicalon and Sylramic tows were also measured in air and argon from 1200 to 1400 C. Although displaying transient and environmental effects similar to single fibers, the tows crept faster at short times and slower at long times. This resulted in the tow rupture strengths at long time being much greater than the rupture strengths of single fibers. The CMC implications of the tow results are discussed, as well as the benefits and limitations of tow testing.

Combinatorial drug delivery strategy employing nano-curcumin and nano-MiADMSA for the treatment of arsenic intoxication in mouse.

PubMed

Kushwaha, Pramod; Yadav, Abhishek; Samim, M; Flora, S J S

2018-04-25

Chelation therapy is the mainstream treatment for heavy metal poisoning. Apart from this, therapy using antioxidant/herbal extracts are the other strategies now commonly being tried for the treatment. We have previously reported individual beneficial efficacy of nanoparticle mediated administration of an antioxidant like 'curcumin' and an arsenic chelator 'monoisoamyl 2,3-dimercaptosuccinic acid (MiADMSA)' for the treatment of arsenic toxicity compared to bulk drugs. The present paper investigates our hypothesis that a combination drug delivery therapy employing two nanosystems, a chelator and a strong antioxidant, may produce more pronounced therapeutic effects compared to individual effects in the treatment of arsenic toxicity. An in-vivo study was conducted wherein arsenic as sodium arsenite (100 ppm) was administered in drinking water for 5 months to Swiss albino mice. This was followed by a treatment protocol comprising of curcumin encapsulated chitosan nanoparticles (nano-curcumin, 15 mg/kg, orally for 1 month) either alone or in combination with MiADMSA encapsulated polymeric nanoparticles (nano-MiADMSA, 50 mg/kg for last 5 days) to evaluate the therapeutic potential of the combination treatment. Our results demonstrated that co-treatment with nano-curcumin and nano-MiADMSA provided beneficial effects in a synergistic way on the adverse changes in oxidative stress parameters and metal status induced by arsenic. Copyright © 2018 Elsevier B.V. All rights reserved.

Red-green-blue (RGB) light generator using tapered fiber pumped with a frequency-doubled Yb-fiber laser.

PubMed

Rusu, M; Kivistö, Samuli; Gawith, C; Okhotnikov, O

2005-10-17

We report on successful realization of a picosecond visible-continuum source embedding a single mode fiber taper. The output of ytterbium mode-locked fiber laser was frequency doubled in a periodically-polled lithium niobate (PPLN) crystal to produce green pump light. Spectral brightness of the white light generated in the tapered fiber was improved by limiting the broadening just to the visible wavelengths. The influence of taper parameters, particularly the dispersion, on white light spectrum has been studied.

Red-green-blue (RGB) light generator using tapered fiber pumped with a frequency-doubled Yb-fiber laser

NASA Astrophysics Data System (ADS)

Rusu, M.; Kivistö, Samuli; Gawith, C. B. E.; Okhotnikov, O. G.

2005-10-01

We report on successful realization of a picosecond visible-continuum source embedding a single mode fiber taper. The output of ytterbium mode-locked fiber laser was frequency doubled in a periodically-polled lithium niobate (PPLN) crystal to produce green pump light. Spectral brightness of the white light generated in the tapered fiber was improved by limiting the broadening just to the visible wavelengths. The influence of taper parameters, particularly the dispersion, on white light spectrum has been studied.

Combinatorial Nano-Bio Interfaces.

PubMed

Cai, Pingqiang; Zhang, Xiaoqian; Wang, Ming; Wu, Yun-Long; Chen, Xiaodong

2018-06-08

Nano-bio interfaces are emerging from the convergence of engineered nanomaterials and biological entities. Despite rapid growth, clinical translation of biomedical nanomaterials is heavily compromised by the lack of comprehensive understanding of biophysicochemical interactions at nano-bio interfaces. In the past decade, a few investigations have adopted a combinatorial approach toward decoding nano-bio interfaces. Combinatorial nano-bio interfaces comprise the design of nanocombinatorial libraries and high-throughput bioevaluation. In this Perspective, we address challenges in combinatorial nano-bio interfaces and call for multiparametric nanocombinatorics (composition, morphology, mechanics, surface chemistry), multiscale bioevaluation (biomolecules, organelles, cells, tissues/organs), and the recruitment of computational modeling and artificial intelligence. Leveraging combinatorial nano-bio interfaces will shed light on precision nanomedicine and its potential applications.

A nanoscale bio-inspired light-harvesting system developed from self-assembled alkyl-functionalized metallochlorin nano-aggregates

NASA Astrophysics Data System (ADS)

Ocakoglu, Kasim; Joya, Khurram S.; Harputlu, Ersan; Tarnowska, Anna; Gryko, Daniel T.

2014-07-01

Self-assembled supramolecular organization of nano-structured biomimetic light-harvesting modules inside solid-state nano-templates can be exploited to develop excellent light-harvesting materials for artificial photosynthetic devices. We present here a hybrid light-harvesting system mimicking the chlorosomal structures of the natural photosynthetic system using synthetic zinc chlorin units (ZnChl-C6, ZnChl-C12 and ZnChl-C18) that are self-aggregated inside the anodic aluminum oxide (AAO) nano-channel membranes. AAO nano-templates were modified with a TiO2 matrix and functionalized with long hydrophobic chains to facilitate the formation of supramolecular Zn-chlorin aggregates. The transparent Zn-chlorin nano-aggregates inside the alkyl-TiO2 modified AAO nano-channels have a diameter of ~120 nm in a 60 μm length channel. UV-Vis studies and fluorescence emission spectra further confirm the formation of the supramolecular ZnChl aggregates from monomer molecules inside the alkyl-functionalized nano-channels. Our results prove that the novel and unique method can be used to produce efficient and stable light-harvesting assemblies for effective solar energy capture through transparent and stable nano-channel ceramic materials modified with bio-mimetic molecular self-assembled nano-aggregates.Self-assembled supramolecular organization of nano-structured biomimetic light-harvesting modules inside solid-state nano-templates can be exploited to develop excellent light-harvesting materials for artificial photosynthetic devices. We present here a hybrid light-harvesting system mimicking the chlorosomal structures of the natural photosynthetic system using synthetic zinc chlorin units (ZnChl-C6, ZnChl-C12 and ZnChl-C18) that are self-aggregated inside the anodic aluminum oxide (AAO) nano-channel membranes. AAO nano-templates were modified with a TiO2 matrix and functionalized with long hydrophobic chains to facilitate the formation of supramolecular Zn-chlorin aggregates. The

Modification of wood fiber using steam

Treesearch

Roger Rowell; Sandra Lange; Jim McSweeny; Mark Davis

2002-01-01

High temperature steam treatment of wood fiber in a closed press during fiberboard pressing and then cooling the fiberboard while still under pressure to below the glass transition temperature of lignin, greatly increased the dimensional stability and decreased the hemicellulose content of the fiberboards produced. For example, after pressing aspen fiber four minutes...

Moisture sorption properties of composite boards from esterified aspen fiber

Treesearch

C. Clemons; R. A. Young; R. M. Rowell

1992-01-01

One barrier to producing wood-plastic composites with wood fiber is the poor thermoplasticity of wood fiber. The objective of our study was to determine the plasticization of chemically modified wood fiber through tests on unmodified and esterified fiberboards. Attrition-milled aspen fiber was esterified with neat acetic, maleic, or succinic anhydride. Fourier...

Lifetime Prediction of Nano-Silica based Glass Fibre/Epoxy composite by Time Temperature Superposition Principle

NASA Astrophysics Data System (ADS)

Anand, Abhijeet; Banerjee, Poulami; Prusty, Rajesh Kumar; Ray, Bankin Chandra

2018-03-01

The incorporation of nano fillers in Fibre reinforced polymer (FRP) composites has been a source of experimentation for researchers. Addition of nano fillers has been found to improve mechanical, thermal as well as electrical properties of Glass fibre reinforced polymer (GFRP) composites. The in-plane mechanical properties of GFRP composite are mainly controlled by fibers and therefore exhibit good values. However, composite exhibits poor through-thickness properties, in which the matrix and interface are the dominant factors. Therefore, it is conducive to modify the matrix through dispersion of nano fillers. Creep is defined as the plastic deformation experienced by a material for a temperature at constant stress over a prolonged period of time. Determination of Master Curve using time-temperature superposition principle is conducive for predicting the lifetime of materials involved in naval and structural applications. This is because such materials remain in service for a prolonged time period before failure which is difficult to be kept marked. However, the failure analysis can be extrapolated from its behaviour in a shorter time at an elevated temperature as is done in master creep analysis. The present research work dealt with time-temperature analysis of 0.1% SiO2-based GFRP composites fabricated through hand-layup method. Composition of 0.1% for SiO2nano fillers with respect to the weight of the fibers was observed to provide optimized flexural properties. Time and temperature dependence of flexural properties of GFRP composites with and without nano SiO2 was determined by conducting 3-point bend flexural creep tests over a range of temperature. Stepwise isothermal creep tests from room temperature (30°C) to the glass transition temperature Tg (120°C) were performed with an alternative creep/relaxation period of 1 hour at each temperature. A constant stress of 40MPa was applied during the creep tests. The time-temperature superposition principle was

Self-Powered Active Sensor with Concentric Topography of Piezoelectric Fibers.

PubMed

Fuh, Yiin Kuen; Huang, Zih Ming; Wang, Bo Sheng; Li, Shan Chien

2017-12-01

In this study, we demonstrated a flexible and self-powered sensor based on piezoelectric fibers in the diameter range of nano- and micro-scales. Our work is distinctively different from previous electrospinning research; we fabricated this apparatus precisely via near-field electrospinning which has a spectacular performance to harvest mechanical deformation in arbitrary direction and a novel concentrically circular topography. There are many piezoelectric devices based on electrospinning polymeric fibers. However, the fibers were mostly patterned in parallel lines and they could be actuated in limited direction only. To overcome this predicament, we re-arranged the parallel alignment into concentric circle pattern which made it possible to collect the mechanical energy whenever the deformation is along same axis or not. Despite the change of topography, the output voltage and current could still reach to 5 V and 400 nA, respectively, despite the mechanical deformation was from different direction. This new arbitrarily directional piezoelectric generator with concentrically circular topography (PGCT) allowed the piezoelectric device to harvest more mechanical energy than the one-directional alignment fiber-based devices, and this PGCT could perform even better output which promised more versatile and efficient using as a wearable electronics or sensor.

Comparison of detonation spreading in pressed ultra-fine and nano-TATB

NASA Astrophysics Data System (ADS)

Olles, Joseph; Wixom, Ryan; Knepper, Robert; Yarrington, Cole; Patel, Rajen; Stepanov, Victor

2017-06-01

Detonation spreading behavior in insensitive high explosives is an important performance characteristic for initiation-train design. In the past, several variations of the floret test have been used to study this phenomenon. Commonly, dent blocks or multi-fiber optical probes were employed for reduced cost and complexity. We devised a floret-like test, using minimal explosive material, to study the detonation spreading in nano-TATB as compared to ultra-fine TATB. Our test uses a streak camera, combined with photonic Doppler velocimetry, to image the breakout timing and quantify the output particle velocity. The TATB acceptor pellets are initiated using an explosively-driven aluminum flyer with a well characterized velocity. We characterized the two types of TATB by assessing purity, particle morphology, and the microstructure of the consolidated pellets. Our results align with published data for ultra-fine TATB, however the nano-TATB shows a distinct difference where output has a strong dependence on density. The results indicate that control over pellet pore size and pressing density may be used to optimize detonation spreading behavior.

Production of mullite fibers