Aligned fibers direct collective cell migration to engineer closing and nonclosing wound gaps

PubMed Central

Sharma, Puja; Ng, Colin; Jana, Aniket; Padhi, Abinash; Szymanski, Paige; Lee, Jerry S. H.; Behkam, Bahareh; Nain, Amrinder S.

2017-01-01

Cell emergence onto damaged or organized fibrous extracellular matrix (ECM) is a crucial precursor to collective cell migration in wound closure and cancer metastasis, respectively. However, there is a fundamental gap in our quantitative understanding of the role of local ECM size and arrangement in cell emergence–based migration and local gap closure. Here, using ECM-mimicking nanofibers bridging cell monolayers, we describe a method to recapitulate and quantitatively describe these in vivo behaviors over multispatial (single cell to cell sheets) and temporal (minutes to weeks) scales. On fiber arrays with large interfiber spacing, cells emerge (invade) either singularly by breaking cell–cell junctions analogous to release of a stretched rubber band (recoil), or in groups of few cells (chains), whereas on closely spaced fibers, multiple chains emerge collectively. Advancing cells on fibers form cell streams, which support suspended cell sheets (SCS) of various sizes and curvatures. SCS converge to form local gaps that close based on both the gap size and shape. We document that cell stream spacing of 375 µm and larger hinders SCS advancement, thus providing abilities to engineer closing and nonclosing gaps. Altogether we highlight the importance of studying cell-fiber interactions and matrix structural remodeling in fundamental and translational cell biology. PMID:28747440

Literature review on use of nonwood plant fibers for building materials and panels

Treesearch

John A. Youngquist; Brent E. English; Roger C. Scharmer; Poo Chow; Steven R. Shook

1994-01-01

The research studies included in this review focus on the use of nonwood plant fibers for building materials and panels. Studies address (1) methods for efficiently producing building materials and panels from nonwood plant fibers; (2) treatment of fibers prior to board production; (3) process variables, such as press time and temperature, press pressure, and type of...

Elastic waves in periodic and non-periodic sets of hollow cylinders

NASA Astrophysics Data System (ADS)

Nikitov, S. A.; Gulyaev, Yu. V.; Lisenkov, I. V.; Popov, R. S.; Grigorievkii, A. V.; Grigorievkii, V. I.

2008-06-01

Two ways of modeling of elastic wave propagation in microstructured acoustic fiber are considered. First one is the calculation of band gap parameters by FEM for phononic crystal forming cross section of fiber. Second one is immediate calculation of dispersion characteristics of elastic fiber containing hole cylindric chanels. For fiber made of fused β quarz numerical results are proposed. For the first type full forbidden gap obtained and for second two different types of modes was found.

Mach-Zehnder atom interferometer inside an optical fiber

NASA Astrophysics Data System (ADS)

Xin, Mingjie; Leong, Wuiseng; Chen, Zilong; Lan, Shau-Yu

2017-04-01

Precision measurement with light-pulse grating atom interferometry in free space have been used in the study of fundamental physics and applications in inertial sensing. Recent development of photonic band-gap fibers allows light for traveling in hollow region while preserving its fundamental Gaussian mode. The fibers could provide a very promising platform to transfer cold atoms. Optically guided matter waves inside a hollow-core photonic band-gap fiber can mitigate diffraction limit problem and has the potential to bring research in the field of atomic sensing and precision measurement to the next level of compactness and accuracy. Here, we will show our experimental progress towards an atom interferometer in optical fibers. We designed an atom trapping scheme inside a hollow-core photonic band-gap fiber to create an optical guided matter waves system, and studied the coherence properties of Rubidium atoms in this optical guided system. We also demonstrate a Mach-Zehnder atom interferometer in the optical waveguide. This interferometer is promising for precision measurements and designs of mobile atomic sensors.

Experimental investigation of sound absorption properties of perforated date palm fibers panel

NASA Astrophysics Data System (ADS)

Elwaleed, A. K.; Nikabdullah, N.; Nor, M. J. M.; Tahir, M. F. M.; Zulkifli, R.

2013-06-01

This paper presents the sound absorption properties of a natural waste of date palm fiber perforated panel. A single layer of the date palm fibers was tested in this study for its sound absorption properties. The experimental measurements were carried out using impedance tube at the acoustic lab, Faculty of Engineering, Universiti Kebangsaan Malaysia. The experiment was conducted for the panel without air gap, with air gap and with perforated plate facing. Three air gap thicknesses of 10 mm, 20 mm and 30 mm were used between the date palm fiber sample and the rigid backing of the impedance tube. The results showed that when facing the palm date fiber sample with perforated plate the sound absorption coefficient improved at the higher and lower frequency ranges. This increase in sound absorption coincided with reduction in medium frequency absorption. However, this could be improved by using different densities or perforated plate with the date palm fiber panel.

Novel Fabry-Perot fiber optic sensor with multiple applications

NASA Astrophysics Data System (ADS)

Chen, Xiaopei; Shen, Fabin; Wang, Anbo; Wang, Zhuang; Zhang, Yan

2004-12-01

A novel Intrinsic Fabry-Perot fiber-optic sensor is presented in this paper. The sensors were made through two simple steps: wet chemical etch and fusion splice. Micro air-gaps were generated inside the fibers and functioned as reflective mirrors. This procedure not only provides a simple and cost effective technology for fabricating intrinsic Fabry-Perot Interferometric (IFPI) fiber sensors, but also provides two possible IFPI structures. Both of the fiber cavity between the air-gaps or the air-gap and cleaved fiber end can be used as sensing elements. With these two structures, this sensor can be used to measure the temperature, strain, pressure, refractive index of chemicals and the thin film thickness by itself. Multi-point measurements can also be achieved by multiplexing. Furthermore, it also can be multiplexed with other sensors such as Long Period Gratings (LPG) to provide compensations for other perturbation sensing. Theoretical and experimental studies of two sensor structures are described. Experimental results show that high resolution and high sensitivity can be obtained with appropriate signal processing.

Connexin hemichannels mediate glutathione transport and protect lens fiber cells from oxidative stress.

PubMed

Shi, Wen; Riquelme, Manuel A; Gu, Sumin; Jiang, Jean X

2018-03-21

Elevated oxidized stress contributes to lens cataracts, and gap junctions play important roles in maintaining lens transparency. As well as forming gap junctions, connexin (Cx) proteins also form hemichannels. Here, we report a new mechanism whereby hemichannels mediate transport of reductant glutathione into lens fiber cells and protect cells against oxidative stress. We found that Cx50 (also known as GJA8) hemichannels opened in response to H 2 O 2 in lens fiber cells but that transport through the channels was inhibited by two dominant-negative mutants in Cx50, Cx50P88S, which inhibits transport through both gap junctions and hemichannels, and Cx50H156N, which only inhibits transport through hemichannels and not gap junctions. Treatment with H 2 O 2 increased the number of fiber cells undergoing apoptosis, and this increase was augmented with dominant-negative mutants that disrupted both hemichannels formed from Cx46 (also known as GJA3) and Cx50, while Cx50E48K, which only impairs gap junctions, did not have such an effect. Moreover, hemichannels mediate uptake of glutathione, and this uptake protected lens fiber cells against oxidative stress, while hemichannels with impaired transport had less protective benefit from glutathione. Taken together, these results show that oxidative stress activates connexin hemichannels in the lens fiber cells and that hemichannels likely protect lens cell against oxidative damage through transporting extracellular reductants. © 2018. Published by The Company of Biologists Ltd.

Evaluation of specific neural marker GAP-43 and TH combined with Masson-trichrome staining for forensic autopsy cases with old myocardial infarction.

PubMed

Yu, Tian-Shui; Wang, Xu; Zhang, Hai-Dong; Bai, Ru-Feng; Zhao, Rui; Guan, Da-Wei

2018-01-01

It has been a puzzling forensic task to determine the cause of death as a result of old myocardial infarction (OMI) in the absence of recognizable acute myocardial infarction. Recent studies indicated that the heterogeneous cardiac nerve sprouting and sympathetic hyperinnervation at border zones of the infarcted site played important roles in sudden cardiac death (SCD). So, the present study explored the value of growth associated protein-43 (GAP-43) and tyrosine hydroxylase (TH) as objective and specific neural biomarkers combined with Masson-trichrome staining for forensic autopsy cases. Myocardium of left ventricle of 58 medicolegal autopsy cases, 12 OMI cases, 12 acute/OMI cases, and 34 control cases, were immunostained with anti-GAP-43 and anti-TH antibodies. Immunoreactivity of GAP-43 and TH identified nerve fibers and vascular wall in OMI cases and acute/OMI cases. Specifically, TH-positive nerve fibers were abundant at border zones of the infarcted site. There were a few GAP-43 and TH expressions in the control cases. With Masson-trichrome staining, collagen fibers were blue and cardiac muscle fibers were pink in marked contrast with the surrounding tissue, which improved the location of nerve fibers. Thus, these findings suggest that immunohistochemical detection of GAP-43 and TH combined with Masson-trichrome staining can provide the evidence for the medicolegal expertise of SCD due to OMI, and further demonstrate a close relationship between sympathetic hyperinnervation and SCD.

Dual-probe near-field fiber head with gap servo control for data storage applications.

PubMed

Fang, Jen-Yu; Tien, Chung-Hao; Shieh, Han-Ping D

2007-10-29

We present a novel fiber-based near-field optical head consisting of a straw-shaped writing probe and a flat gap sensing probe. The straw-shaped probe with a C-aperture on the end face exhibits enhanced transmission by a factor of 3 orders of magnitude over a conventional fiber probe due to a hybrid effect that excites both propagation modes and surface plasmon waves. In the gap sensing probe, the spacing between the probe and the disk surface functions as an external cavity. The high sensitivity of the output power to the change in the gap width is used as a feedback control signal. We characterize and design the straw-shaped writing probe and the flat gap sensing probe. The dual-probe system is installed on a conventional biaxial actuator to demonstrate the capability of flying over a disk surface with nanometer position precision.

Loss-compensation technique using a split-spectrum approach for optical fiber air-gap intensity-based sensors

NASA Astrophysics Data System (ADS)

Wang, Anbo; Miller, Mark S.; Gunther, Michael F.; Murphy, Kent A.; Claus, Richard O.

1993-03-01

A self-referencing technique compensating for fiber losses and source fluctuations in air-gap intensity-based optical fiber sensors is described and demonstrated. A resolution of 0.007 micron has been obtained over a measurement range of 0-250 microns for an intensity-based displacement sensor using this referencing technique. The sensor is shown to have minimal sensitivity to fiber bending losses and variations in the LED input power. A theoretical model for evaluation of step-index multimode optical fiber splice is proposed. The performance of the sensor as a displacement sensor agrees well with the theoretical analysis.

Optical Diagnostics of Multi-Gap Gas Switches for Linear Transformer Drivers

NASA Astrophysics Data System (ADS)

Sheng, Liang; Li, Yang; Sun, Tieping; Cong, Peitian; Zhang, Mei; Peng, Bodong; Zhao, Jizhen; Yue, Zhiqin; Wei, Fuli; Yuan, Yuan

2014-07-01

The trigger characteristics of a multi-gap gas switch with double insulating layers, a square-groove electrode supporter and a UV pre-ionizing structure are investigated aided by a high sensitivity fiber-bundle array detector, a UV fiber detector, and a framing camera, in addition to standard electrical diagnostics. The fiber-bundle-array detector is used to track the turn-on sequence of each electrode gap at a timing precision of 0.6 ns. Each fiber bundle, including five fibers with different azimuth angles, aims at the whole emitting area of each electrode gap and is fed to a photomultiplier tube. The UV fiber detector with a spectrum response of 260-320 nm, including a fused-quartz fiber of 200 μm in diameter and a solar-blinded photomultiplier tube, is adopted to study the effect of UV pre-ionizing on trigger characteristics. The framing camera, with a capacity of 4 frames per shot and an exposure time of 5 ns, is employed to capture the evolution of channel arcs. Based on the turn-on light signal of each electrode gap, the breakdown delay is divided into statistical delay and formative delay. A decrease in both of them, a smaller switch jitter and more channel arcs are observed with lower gas pressure. An increase in trigger voltage can reduce the statistical delay and its jitter, while higher trigger voltage has a relatively small influence on the formative delay and the number of channel arcs. With the UV pre-ionizing structure at 0.24 MPa gas pressure and 60 kV trigger voltage, the statistical delay and its jitter can be reduced by 1.8 ns and 0.67 ns, while the formative delay and its jitter can only be reduced by 0.5 ns and 0.25 ns.

Nondestructive testing of externally reinforced structures for seismic retrofitting using flax fiber reinforced polymer (FFRP) composites

NASA Astrophysics Data System (ADS)

Ibarra-Castanedo, C.; Sfarra, S.; Paoletti, D.; Bendada, A.; Maldague, X.

2013-05-01

Natural fibers constitute an interesting alternative to synthetic fibers, e.g. glass and carbon, for the production of composites due to their environmental and economic advantages. The strength of natural fiber composites is on average lower compared to their synthetic counterparts. Nevertheless, natural fibers such as flax, among other bast fibers (jute, kenaf, ramie and hemp), are serious candidates for seismic retrofitting applications given that their mechanical properties are more suitable for dynamic loads. Strengthening of structures is performed by impregnating flax fiber reinforced polymers (FFRP) fabrics with epoxy resin and applying them to the component of interest, increasing in this way the load and deformation capacities of the building, while preserving its stiffness and dynamic properties. The reinforced areas are however prompt to debonding if the fabrics are not mounted properly. Nondestructive testing is therefore required to verify that the fabric is uniformly installed and that there are no air gaps or foreign materials that could instigate debonding. In this work, the use of active infrared thermography was investigated for the assessment of (1) a laboratory specimen reinforced with FFRP and containing several artificial defects; and (2) an actual FFRP retrofitted masonry wall in the Faculty of Engineering of the University of L'Aquila (Italy) that was seriously affected by the 2009 earthquake. Thermographic data was processed by advanced signal processing techniques, and post-processed by computing the watershed lines to locate suspected areas. Results coming from the academic specimen were compared to digital speckle photography and holographic interferometry images.

Efficient terahertz wave generation from GaP crystals pumped by chirp-controlled pulses from femtosecond photonic crystal fiber amplifier

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

Li, Jiang; Shi, Junkai; Xu, Baozhong

2014-01-20

A chirp-tunable femtosecond 10 W, 42 MHz photonic-crystal-fiber oscillator-amplifier system that is capable of delivering sub-60 fs light pulses at 1040 nm is used to demonstrate high-efficiency terahertz radiation generation via optical rectification in GaP crystals only a few millimeters in length. The optimization of the chirp of the fiber-laser pulses is shown to radically enhance the terahertz output, indicating one possible way to more efficiently use these extended nonlinear crystals in compact fiber-pumped terahertz radiation sources.

Diode pumped alkali vapor fiber laser

DOEpatents

Payne, Stephen A.; Beach, Raymond J.; Dawson, Jay W.; Krupke, William F.

2007-10-23

A method and apparatus is provided for producing near-diffraction-limited laser light, or amplifying near-diffraction-limited light, in diode pumped alkali vapor photonic-band-gap fiber lasers or amplifiers. Laser light is both substantially generated and propagated in an alkali gas instead of a solid, allowing the nonlinear and damage limitations of conventional solid core fibers to be circumvented. Alkali vapor is introduced into the center hole of a photonic-band-gap fiber, which can then be pumped with light from a pump laser and operated as an oscillator with a seed beam, or can be configured as an amplifier.

Diode pumped alkali vapor fiber laser

DOEpatents

Payne, Stephen A [Castro Valley, CA; Beach, Raymond J [Livermore, CA; Dawson, Jay W [Livermore, CA; Krupke, William F [Pleasanton, CA

2006-07-26

A method and apparatus is provided for producing near-diffraction-limited laser light, or amplifying near-diffraction-limited light, in diode pumped alkali vapor photonic-band-gap fiber lasers or amplifiers. Laser light is both substantially generated and propagated in an alkali gas instead of a solid, allowing the nonlinear and damage limitations of conventional solid core fibers to be circumvented. Alkali vapor is introduced into the center hole of a photonic-band-gap fiber, which can then be pumped with light from a pump laser and operated as an oscillator with a seed beam, or can be configured as an amplifier.

Dietary Fiber Gap and Host Gut Microbiota.

PubMed

Han, Meng; Wang, Congmin; Liu, Ping; Li, Defa; Li, Yuan; Ma, Xi

2017-05-10

Accumulating evidence is dramatically increasing the access to the facts that the gut microbiota plays a pivotal role in host metabolism and health, which revealed the possibility of a plethora of associations between gut bacteria and human diseases. Several functional roles are carried out by a major class of the host's diet, such as fiber. Fiber is the main source of microbiota-accessible carbohydrate in the diet of humans. In the modern diet, it is difficult to intake sufficient dietary fiber as recommended. The low-fiber diet in the modern life, known as fiber gap, can trigger a substantial depletion of the human gut microbiota diversity and beneficial metabolites. The short-chain fatty acids are regarded as one of the major microbial metabolites of dietary fibers, which can improve intestinal mucosal immunity, as well as to be a source of energy for the liver. Thus, the loss of microbiota diversity has a potential negative function to various aspects of host health. Actually, the real "fiber gap" for ideal health and maintaining microbial diversity might be even more serious than currently appreciated. Herein, we briefly discuss the interactions between gut microbiota and the host diet, focusing specifically on the low-fiber diet. Gut bacteria in the context of the development of host low-fiber diets, which may lead to health and disorders, particularly include metabolic syndrome and obesity-related disease, IBD liver, disease, and colorectal cancer. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Identifying Practical Solutions to Meet America’s Fiber Needs: Proceedings from the Food & Fiber Summit

PubMed Central

Mobley, Amy R.; Jones, Julie Miller; Rodriguez, Judith; Slavin, Joanne; Zelman, Kathleen M.

2014-01-01

Fiber continues to be singled out as a nutrient of public health concern. Adequate intakes of fiber are associated with reduced risk for cardiovascular disease, cancer, diabetes, certain gastrointestinal disorders and obesity. Despite ongoing efforts to promote adequate fiber through increased vegetable, fruit and whole-grain intakes, average fiber consumption has remained flat at approximately half of the recommended daily amounts. Research indicates that consumers report increasingly attempting to add fiber-containing foods, but there is confusion around fiber in whole grains. The persistent and alarmingly low intakes of fiber prompted the “Food & Fiber Summit,” which assembled nutrition researchers, educators and communicators to explore fiber’s role in public health, current fiber consumption trends and consumer awareness data with the objective of generating opportunities and solutions to help close the fiber gap. The summit outcomes highlight the need to address consumer confusion and improve the understanding of sources of fiber, to recognize the benefits of various types of fibers and to influence future dietary guidance to provide prominence and clarity around meeting daily fiber recommendations through a variety of foods and fiber types. Potential opportunities to increase fiber intake were identified, with emphasis on meal occasions and food categories that offer practical solutions for closing the fiber gap. PMID:25006857

Gap junctions on hippocampal mossy fiber axons demonstrated by thin-section electron microscopy and freeze–fracture replica immunogold labeling

PubMed Central

Hamzei-Sichani, Farid; Kamasawa, Naomi; Janssen, William G. M.; Yasumura, Thomas; Davidson, Kimberly G. V.; Hof, Patrick R.; Wearne, Susan L.; Stewart, Mark G.; Young, Steven R.; Whittington, Miles A.; Rash, John E.; Traub, Roger D.

2007-01-01

Gap junctions have been postulated to exist between the axons of excitatory cortical neurons based on electrophysiological, modeling, and dye-coupling data. Here, we provide ultrastructural evidence for axoaxonic gap junctions in dentate granule cells. Using combined confocal laser scanning microscopy, thin-section transmission electron microscopy, and grid-mapped freeze–fracture replica immunogold labeling, 10 close appositions revealing axoaxonic gap junctions (≈30–70 nm in diameter) were found between pairs of mossy fiber axons (≈100–200 nm in diameter) in the stratum lucidum of the CA3b field of the rat ventral hippocampus, and one axonal gap junction (≈100 connexons) was found on a mossy fiber axon in the CA3c field of the rat dorsal hippocampus. Immunogold labeling with two sizes of gold beads revealed that connexin36 was present in that axonal gap junction. These ultrastructural data support computer modeling and in vitro electrophysiological data suggesting that axoaxonic gap junctions play an important role in the generation of very fast (>70 Hz) network oscillations and in the hypersynchronous electrical activity of epilepsy. PMID:17640909

Dietary Fiber Analysis of Four Pulses Using AOAC 2011.25: Implications for Human Health.

PubMed

Chen, Yiran; McGee, Rebecca; Vandemark, George; Brick, Mark; Thompson, Henry J

2016-12-21

Chickpeas, common beans, dry peas, and lentils are pulse crops that have been a cornerstone of the human diet since the inception of agriculture. However, the displacement of pulses from the diet by low fiber protein alternatives has resulted in a pervasive deficiency referred to as the dietary fiber gap. Using an analytical method American Association of Analytical Chemists (AOAC) 2011.25 that conforms to the Codex Alimentarius Commission consensus definition for dietary fiber, the fiber content of these pulse crops was evaluated in seed types used for commercial production. These pulse crops have 2 to 3 times more fiber per 100 g edible portion than other dietary staples. Moreover, there is marked variation in fiber content among cultivars of the same crop. We conclude that pulse crop consumption should be emphasized in efforts to close the dietary fiber gap. The substantial differences in fiber content among currently available cultivars within a crop can be used to further improve gains in fiber intake without the need to change dietary habits. This provides a rationale for cultivar-based food labeling.

Dietary Fiber Analysis of Four Pulses Using AOAC 2011.25: Implications for Human Health

PubMed Central

Chen, Yiran; McGee, Rebecca; Vandemark, George; Brick, Mark; Thompson, Henry J.

2016-01-01

Chickpeas, common beans, dry peas, and lentils are pulse crops that have been a cornerstone of the human diet since the inception of agriculture. However, the displacement of pulses from the diet by low fiber protein alternatives has resulted in a pervasive deficiency referred to as the dietary fiber gap. Using an analytical method American Association of Analytical Chemists (AOAC) 2011.25 that conforms to the Codex Alimentarius Commission consensus definition for dietary fiber, the fiber content of these pulse crops was evaluated in seed types used for commercial production. These pulse crops have 2 to 3 times more fiber per 100 g edible portion than other dietary staples. Moreover, there is marked variation in fiber content among cultivars of the same crop. We conclude that pulse crop consumption should be emphasized in efforts to close the dietary fiber gap. The substantial differences in fiber content among currently available cultivars within a crop can be used to further improve gains in fiber intake without the need to change dietary habits. This provides a rationale for cultivar-based food labeling. PMID:28009809

Evaluation of Shear Tie Connectors for Use in Insulated Concrete Sandwich Panels

DTIC Science & Technology

2009-12-01

stainless steel, galvanized carbon steel, carbon fiber reinforced polymers (CFRP), glass fiber reinforced polymer (GFRP), and basalt fiber reinforced polymer...Glass Fiber Reinforced Polymer (GFRP) Delta Tie produced by Dayton Superior; • (B) THERMOMASS® composite GFRP pins; • (C) THERMOMASS® non-composite...GFRP pins; • (D) Altus Group CFRP Grid; • (E) Universal Building products GFRP Teplo Tie; and • (F) Universal Building products Basalt FRP

Exposure to airborne asbestos in buildings

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

Lee, R.J.; Van Orden, D.R.; Corn, M.

The concentration of airborne asbestos in buildings and its implication for the health of building occupants is a major public health issue. A total of 2892 air samples from 315 public, commercial, residential, school, and university buildings has been analyzed by transmission electron microscopy. The buildings that were surveyed were the subject of litigation related to suits alleging the general building occupants were exposed to a potential health hazard as a result of exposure to the presence of asbestos containing materials (ACM). The average concentration of all asbestos structures was 0.02 structures/ml (s/ml) and the average concentration of asbestos greatermore » than or equal to 5 microns long was 0.00013 fibers/ml (f/ml). The concentration of asbestos was higher in schools than in other buildings. In 48% of indoor samples and 75% of outdoor samples, no asbestos fibers were detected. The observed airborne concentration in 74% of the indoor samples and 96% of the outdoor samples is below the Asbestos Hazard Emergency Response Act clearance level of 0.01 s/ml. Finally, using those fibers which could be seen optically, all indoor samples and all outdoor samples are below the Occupational Safety and Health Administration permissible exposure level of 0.1 f/ml for fibers greater than or equal to 5 microns in length. These results provide substantive verification of the findings of the U.S. Environmental Protection Agency public building study which found very low ambient concentrations of asbestos fibers in buildings with ACM, irrespective of the condition of the material in the buildings.« less

Poly(D,L-Lactide-Co-Glycolide) Tubes With Multifilament Chitosan Yarn or Chitosan Sponge Core in Nerve Regeneration.

PubMed

Wlaszczuk, Adam; Marcol, Wiesław; Kucharska, Magdalena; Wawro, Dariusz; Palen, Piotr; Lewin-Kowalik, Joanna

2016-11-01

The influence of different kinds of nerve guidance conduits on regeneration of totally transected rat sciatic nerves through a 7-mm gap was examined. Five different types of conduits made of chitosan and poly(D,L-lactide-co-glycolide) (PLGA) were constructed and tested in vivo. We divided 50 animals into equal groups of 10, with a different type of conduit implanted in each group: chitosan sponge core with an average molecular mass of polymer (Mv) of 287 kDa with 7 channels in a PLGA sleeve, chitosan sponge core with an Mv of 423 kDa with 7 channels in a PLGA sleeve, chitosan sponge core (Mv, 423 kDa) with 13 channels in a PLGA sleeve, chitosan multifilament yarn in a PLGA sleeve, and a PLGA sleeve only. Seven weeks after the operation, we examined the distance covered by regenerating nerve fibers, growing of nerves into the conduit's core, and intensity and type of inflammatory reaction in the conduit, as well as autotomy behavior (reflecting neuropathic pain intensity) in the animals. Two types of conduits were allowing nerve outgrowth through the gap with minor autotomy and minor inflammatory reactions. These were the conduits with chitosan multifilament yarn in a PLGA sleeve and the conduits with 13-channel microcrystalline chitosan sponge in a PLGA sleeve. The type of chitosan used to build the nerve guidance conduit influences the intensity and character of inflammatory reaction present during nerve regeneration, which in turn affects the distance crossed by regenerating nerve fibers, growing of the nerve fibers into the conduit's core, and the intensity of autotomy in the animals. Copyright © 2016 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Detection and localization of building insulation faults using optical-fiber DTS system

NASA Astrophysics Data System (ADS)

Papes, Martin; Liner, Andrej; Koudelka, Petr; Siska, Petr; Cubik, Jakub; Kepak, Stanislav; Jaros, Jakub; Vasinek, Vladimir

2013-05-01

Nowadays the trends in the construction industry are changing at an incredible speed. The new technologies are still emerging on the market. Sphere of building insulation is not an exception as well. One of the major problems in building insulation is usually its failure, whether caused by unwanted mechanical intervention or improper installation. The localization of these faults is quite difficult, often impossible without large intervention into the construction. As a proper solution for this problem might be utilization of Optical-Fiber DTS system based on stimulated Raman scattering. Used DTS system is primary designed for continuous measurement of the temperature along the optical fiber. This system is using standard optical fiber as a sensor, which brings several advantages in its application. First, the optical fiber is relatively inexpensive, which allows to cover a quite large area for a small cost. The other main advantages of the optical fiber are electromagnetic resistance, small size, safety operation in inflammable or explosive area, easy installation, etc. This article is dealing with the detection and localization of building insulation faults using mentioned system.

Developmental and Adult GAP-43 Deficiency in Mice Dynamically Alters Hippocampal Neurogenesis and Mossy Fiber Volume

PubMed Central

Latchney, Sarah E.; Masiulis, Irene; Zaccaria, Kimberly J.; Lagace, Diane C.; Powell, Craig M.; McCasland, James S.; Eisch, Amelia J.

2014-01-01

Growth Associated Protein-43 (GAP-43) is a pre-synaptic protein that plays key roles in axonal growth and guidance and in modulating synapse formation. Previous work has demonstrated that mice lacking one allele of this gene [GAP-43(+/-) mice] exhibit hippocampal structural abnormalities and impaired spatial learning and stress-induced behavioral withdrawal and anxiety (Zaccaria et al., 2010), behaviors that are dependent on proper hippocampal circuitry and function. Given the correlation between hippocampal function, synaptic connectivity, and neurogenesis, we tested if behaviorally-naïve GAP-43(+/-) mice had alterations in either neurogenesis or synaptic connectivity in the hippocampus during early postnatal development and young adulthood, and following behavior testing in older adults. To test our hypothesis, we examined hippocampal cell proliferation (Ki67), number of immature neuroblasts (DCX), and mossy fiber volume (synaptoporin) in behaviorally-naïve postnatal (P) day 9 (P9), P26, and behaviorally-experienced 5-7 month old GAP-43(+/-) and (+/+) littermate mice. P9 GAP-43(+/-) mice had fewer Ki67+ and DCX+ cells compared to (+/+) mice, particularly in the posterior dentate gyrus, and smaller mossy fiber volume in the same region. In young adulthood, however, male GAP-43(+/-) mice had more Ki67+ and DCX+ cells and greater mossy fiber volume in the posterior dentate gyrus relative to male (+/+). These increases were not seen in females. In 5-7 month old GAP-43(+/-) mice whose behaviors were the focus of our prior publication (Zaccaria et al., 2010), there was no global change in number of proliferating or immature neurons relative to (+/+) mice. However, more detailed analysis revealed fewer proliferative DCX+ cells in the anterior dentate gyrus of male GAP-43(+/-) mice compared to male (+/+) mice. This reduction was not observed in females. These results suggest that young GAP-43(+/-) mice have decreased hippocampal neurogenesis and synaptic connectivity, but slightly older mice have greater hippocampal neurogenesis and synaptic connectivity. In conjunction with our previous study, these findings suggest GAP-43 is dynamically involved in early postnatal and adult hippocampal neurogenesis and synaptic connectivity, possibly contributing to the GAP-43(+/-) behavioral phenotype. PMID:24576816

Performance and Characterization of Shear Ties for Use in Insulated Precast Concrete Sandwich Wall Panels

DTIC Science & Technology

2010-11-01

stainless 14 steel, galvanized carbon steel, carbon- fiber -reinforced polymer (CFRP), glass- fiber -reinforced polymer 15 (GFRP), and basalt - fiber ...CFRP Grid, (E) Universal Building Products GFRP Teplo Tie, and (F) Universal Building Products 6 Basalt FRP RockBar. Traditional steel connections...1.6 E Universal Building Products TeploTie GFRP Tie 10 mm dia. x 150 mm F RockBar Basalt FRP Bar 7 in. x 5/16 in. G TSA Manufacturing C-Clip

Split-spectrum intensity-based optical fiber sensors for measurement of microdisplacement, strain, and pressure

NASA Astrophysics Data System (ADS)

Wang, Anbo; Miller, Mark S.; Plante, Angela J.; Gunther, Michael F.; Murphy, Kent A.; Claus, Richard O.

1996-05-01

A self-referencing technique compensating for fiber losses and source fluctuations in reflective air-gap intensity-based optical fiber sensors is described. A dielectric multilayer short-wave-pass filter is fabricated onto or attached to the output end face of the lead-in-lead-out multimode fiber. The incoming broadband light from a white light or a light-emitting diode is partially reflected at the filter. The transmitted light through the filter projects onto a mirror. The light returning from the reflecting mirror is recoupled into the lead-in-lead-out fiber. These two reflections from the filter and the reflecting mirror are spectrally separated at the detector end. The power ratio of these two reflections is insensitive to source fluctuations and fiber-bending loss. However, because the second optical signal depends on the air-gap separation between the end face of the lead-in-lead-out fiber and the reflecting mirror, the ratio provides the information on the air-gap length. A resolution of 0.13 mu m has been obtained over a microdisplacement measurement range of 0-254 mu m. The sensor is shown to be insensitive to both fiber-bending losses and variations in source power. Based on this approach, a fiber-strain sensor was fabricated with a multilayer interference filter directly fabricated on the end face of the fiber. A resolution of 13.4 microstrain was obtained over a measurement range of 0-20,000 microstrain with a gauge length of 10 mm. The split-spectrum method is also incorporated into a diaphragm displacement-based pressure sensor with a demonstrated resolution of 450 Pa over a measurement range of 0-0.8 MPa.

High-power picosecond pulse delivery through hollow core photonic band gap fibers

NASA Astrophysics Data System (ADS)

Michieletto, Mattia; Johansen, Mette M.; Lyngsø, Jens K.; Lægsgaard, Jesper; Bang, Ole; Alkeskjold, Thomas T.

2016-03-01

We demonstrated robust and bend insensitive fiber delivery of high power laser with diffraction limited beam quality for two different kinds of hollow core band gap fibers. The light source for this experiment consists of ytterbium-doped double clad fiber aeroGAIN-ROD-PM85 in a high power amplifier setup. It provided 22ps pulses with a maximum average power of 95W, 40MHz repetition rate at 1032nm (~2.4μJ pulse energy), with M2 <1.3. We determined the facet damage threshold for a 7-cells hollow core photonic bandgap fiber and showed up to 59W average power output for a 5 meters fiber. The damage threshold for a 19-cell hollow core photonic bandgap fiber exceeded the maximum power provided by the light source and up to 76W average output power was demonstrated for a 1m fiber. In both cases, no special attention was needed to mitigate bend sensitivity. The fibers were coiled on 8 centimeters radius spools and even lower bending radii were present. In addition, stimulated rotational Raman scattering arising from nitrogen molecules was measured through a 42m long 19 cell hollow core fiber.

Cyclic Oxidation of FeCrAlY/Al2O3 Composites

NASA Technical Reports Server (NTRS)

Nesbitt, James A.; Draper, Susan L.; Barrett, Charles A.

1999-01-01

Three-ply FeCrAlY/Al2O3 composites and FeCrAlY matrix-only samples were cyclically oxidized at 1000 C and 1100 C for up to 1000 1-hr cycles. Fiber ends were exposed at the ends of the composite samples. Following cyclic oxidation, cracks running parallel to and perpendicular to the fibers were observed on the large surface of the composite. In addition, there was evidence of increased scale damage and spallation around the exposed fiber ends, particularly around the middle ply fibers. This damage was more pronounced at the higher temperature. The exposed fiber ends showed cracking between fibers in the outer plies, occasionally with Fe and Cr-rich oxides growing out of the cracks. Large gaps developed at the fiber/matrix interface around many of the fibers, especially those in the outer plies. Oxygen penetrated many of these gaps resulting in significant oxide formation at the fiber/matrix interface far within the composite sample. Around several fibers, the matrix was also internally oxidized showing Al2O3 precipitates in a radial band around the fibers. The results show that these composites have poor cyclic oxidation resistance due to the CTE mismatch and inadequate fiber/matrix bond strength at temperatures of 1000 C and above.

Optical spectrum measurement of a cell-adhered microcavity for the cell-cycle analysis applications

NASA Astrophysics Data System (ADS)

Saito, Ryusuke; Terakawa, Mitsuhiro; Tanabe, Takasumi

2015-03-01

We build a setup and demonstrate successful measurement of the transmittance spectrum of a whispering gallery mode silica optical microcavity in which NIH 3T3 cells adhered on the top surface to achieve real-time and label-free measurement of the cell cycle. Label-free measurement is expected to prevent the cells to exhibit secondary effect. We build a system that enables the control of the gap distance between the microcavity and the tapered fiber, both of which are placed in the cell culture medium. The optimization of the tapered fiber diameter is the key to measure the spectrum of a microcavity in liquid. A swept wavelength laser light at a wavelength of 766 to 780 nm is used for the measurement. The cavity exhibit a Q of 1 . 0 ×106 in air, where the value is 1 . 0 ×105 in the medium and drops to 3 . 1 ×104 after the cell-adhesion. Still the Q of the microcavity is sufficiently high to detect the change at the cavity surface. Indeed we observe slight spectrum shift toward a longer wavelength, which we believe is due to the adherence of NIH 3T3 cells on the silica microcavity.The successful measurement of the transmittance spectrum of a microcavity in cell culture medium is the first step to realize the analysis of the cell-cycle based on microcavity system.

A modified cross-correlation method for white-light optical fiber extrinsic Fabry-Perot interferometric hydrogen sensors

NASA Astrophysics Data System (ADS)

Yang, Zhen; Zhang, Min; Liao, Yanbiao; Lai, Shurong; Tian, Qian; Li, Qisheng; Zhang, Yi; Zhuang, Zhi

2009-11-01

An extrinsic Fabry-Perot interferometric (EFPI) optical fiber hydrogen sensor based on palladium silver (Pd-Ag) film is designed for hydrogen leakage detection. A modified cross correlation signal processing method for an optical fiber EFPI hydrogen sensor is presented. As the applying of a special correlating factor which advises the effect on the fringe visibility of the gap length and wavelength, the cross correlation method has a high accuracy which is insensitive to light source power drift or changes in attenuation in the fiber, and the segment search method is employed to reduce computation and demodulating speed is fast. The Fabry-Perot gap length resolution of better than 0.2nm is achieved in a certain concentration of hydrogen.

Asbestos release from whole-building demolition of buildings with asbestos-containing material.

PubMed

Perkins, Robert A; Hargesheimer, John; Fourie, Walter

2007-12-01

The whole-building demolition method, which entails one-or two-story buildings pushed down by heavy equipment, loaded into trucks, and hauled away, is generally the most cost-effective means to remove small buildings. For taller buildings, a crane and wrecking ball may be used initially to reduce the height of the building. Demolitions might release asbestos fibers from friable asbestos-containing material (ACM). Fibers also might be released from nominally nonfriable ACM (Categories I and II nonfriable ACM) if it becomes friable after rough handling throughout the whole-building demolition process. This paper reports on asbestos air monitoring from two demolition projects involving ACM. In one building, Category II nonfriable ACM was present because it could not be removed safely prior to demolition. Both projects had large quantities of gypsum wallboard with ACM joint compound and ACM flooring. One building had large quantities of ACM spray-on ceiling material. During the demolitions personal air monitoring of the workers and area air monitoring downwind and around the sites were conducted. The monitoring found the concentrations of fibers detected by phase contrast microscopy were generally well below the permissible exposure limits (PEL) of workers. Electron microcopy analysis of samples at or near the PEL indicated most of the fibers were not asbestos, and the actual asbestos exposure was often below the detection limit of the procedure. The buildings were kept wet with fire hoses during the demolition and that required large quantities of water, 20,000-60,000 gal/day (75-225 m(3)/day). Earlier studies found little asbestos release from buildings containing only nonfriable ACM demolished by this method. This project found a negligible release of asbestos fibers, despite the presence of nonfriable materials that might become friable, such as ACM joint compound and spray-on ACM ceiling coating.

Vulnerability of Quick Disconnect Connectors to Carbon Fibers

NASA Technical Reports Server (NTRS)

Meyers, J. A.

1979-01-01

Unprotected quick disconnect electrical connectors were exposed to fibers of 3mm, 7mm, and 12mm lengths. The average exposure to failure was determined. Results indicate that when the fiber length divided by the airgap is less than one, multiple fibers are required to bridge the gap, and the exposure time to failure rises rapidly.

Test build from Robotic Fiber Placement Machine

NASA Image and Video Library

2015-10-01

MAJID BABAI, LEFT, CHIEF OF THE NONMETALLIC MANUFACTURING BRANCH AT MARSHALL, AND STEPHEN RICHARDSON, LEAD FOR THE STRUCTURAL DEVELOPMENT TEAM, TAKE A CLOSER LOOK AT ONE OF THE FIRST TEST BUILDS MADE BY THE NEW ROBOTIC FIBER PLACEMENT MACHINE BEHIND THEM.

Ultralow-power four-wave mixing with Rb in a hollow-core photonic band-gap fiber.

PubMed

Londero, Pablo; Venkataraman, Vivek; Bhagwat, Amar R; Slepkov, Aaron D; Gaeta, Alexander L

2009-07-24

We demonstrate extremely efficient four-wave mixing with gains greater than 100 at microwatt pump powers and signal-to-idler conversion of 50% in Rb vapor confined to a hollow-core photonic band-gap fiber. We present a theoretical model that demonstrates such efficiency is consistent with the dimensions of the fiber and the optical depths attained. This is, to our knowledge, the largest four-wave mixing gain observed at such low total pump powers and the first demonstrated example of four-wave mixing in an alkali-metal vapor system with a large (approximately 30 MHz) ground state decoherence rate.

The Nature of Accelerating Modes in PBG Fibers

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

Noble, TRobert J.; /SLAC

Transverse magnetic (TM) modes with phase velocities at or just below the speed of light, c, are intended to accelerate relativistic particles in hollow-core, photonic band gap (PBG) fibers. These are so-called 'surface defect modes', being lattice modes perturbed by the defect to have their frequencies shifted into the band gap, and they can have any phase velocity. PBG fibers also support so-called 'core defect modes' which are characterized as having phase velocities always greater than c and never cross the light line. In this paper we explore the nature of these two classes of accelerating modes and compare theirmore » properties.« less

Upregulation of the axonal growth and the expression of substance P and its NK1 receptor in human allergic contact dermatitis.

PubMed

El-Nour, H; Lundeberg, L; Al-Tawil, R; Granlund, A; Lonne-Rahm, S-B; Nordlind, K

2006-01-01

Nerve fibers and sensory neuropeptides substance P and calcitonin gene-related peptide (CGRP) have been reported to be involved in allergic contact dermatitis (ACD). In the present study, we investigated the general innervation (using antibody against protein gene product 9.5, PGP 9.5), axonal growth (using antibody against growth associated protein, GAP-43), CGRP, and substance P with its receptor neurokinin 1 (NK1), in positive epicutaneous reactions to nickel sulphate from nickel-allergic patients, at the peak of inflammation, 72 hr after challenge with the antigen. There was an increased (p < 0.01) number of GAP-43 positive fibers in the eczematous compared with control skin, indicating an increased axonal growth already at 72 hr postchallenge. Double staining revealed a coexpression of CGRP and GAP-43 on dermal nerve fibers. There was no difference in the number of substance P and CGRP positive nerve fibers between eczematous and control skin. However, semiquantification analyses showed an increased expression of substance P positive inflammatory cells, being CD3, CD4, or CD8 positive, and NK1R positive inflammatory cells, being tryptase or CD3 positive. These results indicate a contribution of regenerating nerve fibers and substance P to the contact allergic reaction.

Comparison of Free-Beam- and Fiber-Type CO2 Laser Delivery Systems in Stapes Surgery.

PubMed

Chang, Mun Young; Choi, Hyun Seok; Lee, Sang-Youp; Koo, Ja-Won

2017-07-01

A free-beam-type CO 2 laser, which use a micromanipulator mounted on a microscope as the delivery system, has the merit of not being affected by hand tremor at the time of shooting. However, this delivery system has several disadvantages, including a restricted operation range and a risk of incorrect focusing. A fiber-type CO 2 laser uses a hand-held delivery system and has the opposite merits and demerits. We compared the results of stapes surgery with free-beam and fiber type delivery systems. The study enrolled 36 patients who underwent stapedotomy with free-beam- (n=26) or fiber- (n=10) type CO 2 lasers. The air-bone (AB) gap closure, bone conduction (BC) change, and operating time were evaluated. The AB gap closure was calculated by subtracting the preoperative BC thresholds from the postoperative air conduction thresholds. The BC change was calculated by subtracting the postoperative BC thresholds from the preoperative BC thresholds. The mean operating time was significantly ( p =0.035) shorter in the fiber-type group (72.5±8.2 min) than in the free-beam-type group (80.5±11.4 min). The mean AB gap closure did not differ significantly ( p =0.297) between the free-beamand fiber-type groups (5.8±10.1 and 1.4±6.8 dB, respectively). The mean BC change did not differ significantly ( p =0.873) between the free-beam- and fiber-type groups (2.4±6.9 and 2.8±5.3 dB, respectively). The hearing outcomes did not differ significantly between the two groups. Operating times were significantly shorter using the fiber-type CO 2 laser, while hearing outcomes did not differ significantly between the two groups.

Research on the Application of GRC Material in Exhibition Decoration Engineering

NASA Astrophysics Data System (ADS)

Cai, Yan

2018-03-01

Glass fiber reinforced cement (GRC) is a kind of new building material which is based on cement and take the alkali resistant glass fiber as reinforcing material. It is mainly used in building decoration project and it has many advantages like environmental protection, economical, practical modeling and others. This paper mainly studies the concrete application of GRC material in exhibition building decoration project.

Formation of anisotropic hollow-fiber membranes via thermally induced phase separation

NASA Astrophysics Data System (ADS)

Batarseh, Melanie Turkett

The goal of this research project was to study the formation of anisotropic hollow fiber membranes via thermally induced phase separation (TIPS). This objective included developing a fundamental knowledge of the factors that contribute to anisotropy and studying how anisotropy can be controlled via operational parameters in hollow fiber spinning. The objective was met by creating a model to simulate the mass and heat transfer in the fiber wall during spinning and by experimentally varying spinning parameters and observing the affect on the membrane microstructure. The TIPS membrane formation process consists of forming a homogeneous solution of polymer and diluent and extruding the solution through a spinneret to form a hollow fiber. The fiber is cooled in an air gap followed by a quench bath, which results in phase separation of the solution into a diluent-rich phase dispersed in a continuous polymer-rich liquid phase. The diluent-rich domains grow in size until the polymer-rich phase crystallizes. Then the diluent is removed, and the spaces left behind become the pores of the microporous membrane. Therefore, the size of the diluent-rich domains when the polymer solidifies is related to the size of the pores in the finished membrane. Increasing the polymer concentration of the homogeneous solution or increasing the cooling rate of the phase separated solution decreases the domain size, and thus decreases pore size. An anisotropic membrane, which has a gradation of pore size from small pores at the feed-side to large pores at the permeate-side, can be formed by creating a concentration gradient or a cooling rate gradient across the membrane. In hollow fiber spinning, a concentration gradient can be created by allowing diluent to evaporate from the outside wall of the fiber in the air gap, and a cooling rate gradient can be created by quenching the fiber in a liquid bath. The spinning model calculates concentration and temperature profiles across the hollow fiber wall over time. The model results indicate that spinning temperature, air velocity, and air gap length have a significant effect on the concentration profile in the wall, and spinning temperature and quench temperature have a significant effect on the cooling rate profile. Experimental results indicate that increasing the air gap length from 5 to 50 cm. or increasing the quench temperature from 298 to 323 K has a significant effect on the anisotropic structure of the hollow fiber.

High-Power Fiber Lasers Using Photonic Band Gap Materials

NASA Technical Reports Server (NTRS)

DiDomenico, Leo; Dowling, Jonathan

2005-01-01

High-power fiber lasers (HPFLs) would be made from photonic band gap (PBG) materials, according to the proposal. Such lasers would be scalable in the sense that a large number of fiber lasers could be arranged in an array or bundle and then operated in phase-locked condition to generate a superposition and highly directed high-power laser beam. It has been estimated that an average power level as high as 1,000 W per fiber could be achieved in such an array. Examples of potential applications for the proposed single-fiber lasers include welding and laser surgery. Additionally, the bundled fibers have applications in beaming power through free space for autonomous vehicles, laser weapons, free-space communications, and inducing photochemical reactions in large-scale industrial processes. The proposal has been inspired in part by recent improvements in the capabilities of single-mode fiber amplifiers and lasers to produce continuous high-power radiation. In particular, it has been found that the average output power of a single strand of a fiber laser can be increased by suitably changing the doping profile of active ions in its gain medium to optimize the spatial overlap of the electromagnetic field with the distribution of active ions. Such optimization minimizes pump power losses and increases the gain in the fiber laser system. The proposal would expand the basic concept of this type of optimization to incorporate exploitation of the properties (including, in some cases, nonlinearities) of PBG materials to obtain power levels and efficiencies higher than are now possible. Another element of the proposal is to enable pumping by concentrated sunlight. Somewhat more specifically, the proposal calls for exploitation of the properties of PBG materials to overcome a number of stubborn adverse phenomena that have impeded prior efforts to perfect HPFLs. The most relevant of those phenomena is amplified spontaneous emission (ASE), which causes saturation of gain and power at undesirably low levels, and scattering of light from dopants. In designing a given fiber laser for reduced ASE, care must be taken to maintain a correct fiber structure for eventual scaling to an array of many such lasers such that the interactions among all the members of the array would cause them to operate in phase lock. Hence, the problems associated with improving a single-fiber laser are not entirely separate from the bundling problem, and some designs for individual fiber lasers may be better than others if the fibers are to be incorporated into bundles. Extensive calculations, expected to take about a year, must be performed in order to determine design parameters before construction of prototype individual and fiber lasers can begin. The design effort can be expected to include calculations to optimize overlaps between the electromagnetic modes and the gain media and calculations of responses of PBG materials to electromagnetic fields. Design alternatives and physical responses that may be considered include simple PBG fibers with no intensity-dependent responses, PBG fibers with intensity- dependent band-gap shifting (see figure), and broad-band pumping made possible by use of candidate broad-band pumping media in place of the air or vacuum gaps used in prior PBG fibers.

Contribution study to the thermal insulation of the builders in the desert regions of exploiting gypsum fiber reinforced palm

NASA Astrophysics Data System (ADS)

Hafsi, Fouad; Kriker, Abdelouahed; Abani, Said

2017-02-01

Algerian Desert areas were characterized by very hot climate in summer and very cold in winter. The most widely used building material in these areas are concrete, mortar cement, which has a bad thermal insulation, causing a significant increase in cooling and heating costs; in order to avoid this problem it become a must to replace these materials with a good thermal isolation material and lower production cost. This work is part of the evaluation of local materials by improving their performance in the field of thermal insulation, which is considered a first step in the development of new local materials to be used in the construction field, the material used in this study is the gypsum reinforced with date palm fiber. In fact, Algeria has extraordinary resources in natural fibers (from Palm, Abaca, Hemp…) but without any large valorization in building materials. The aim of this work is then to characterization of those date palm fibers in new building materials approved for use in the construction of buildings in the desert areas. The date palm fibers were added to samples of the gypsum material in the form of cutting layers at different volume fraction, so as to determine the extent of their impact in the improvement of the thermal performance. The results were very satisfactory, reaching improvement rate of 16% for samples gypsum reinforced with single cut fiber form, and 32% of the samples reinforced with fiber in the form of layers.

Reduced thermal sensitivity of hybrid air-core photonic band-gap fiber ring resonator

NASA Astrophysics Data System (ADS)

Feng, Li-shuang; Wang, Kai; Jiao, Hong-chen; Wang, Jun-jie; Liu, Dan-ni; Yang, Zhao-hua

2018-01-01

A novel hybrid air-core photonic band-gap fiber (PBF) ring resonator with twin 90° polarization-axis rotated splices is proposed and demonstrated. Frist, we measure the temperature dependent birefringence coefficient of air-core PBF and Panda fiber. Experimental results show that the relative temperature dependent birefringence coefficient of air-core PBF is 1.42×10-8/°C, which is typically 16 times less than that of Panda fiber. Then, we extract the geometry profile of air-core PBF from scanning electron microscope (SEM) images. Numerical modal is built to distinguish the fast axis and slow axis in the fiber. By precisely setting the length difference in air-core PBF and Panda fiber between two 90° polarization-axis rotated splicing points, the hybrid air-core PBF ring resonator is constructed, and the finesse of the resonator is 8.4. Environmental birefringence variation induced by temperature change can be well compensated, and experimental results show an 18-fold reduction in thermal sensitivity, compared with resonator with twin 0° polarization-axis rotated splices.

Abestos in Buildings: The State Role.

ERIC Educational Resources Information Center

Neilander, Dennis K.; Sacarto, Douglas M.

1988-01-01

The widespread use of asbestos for several decades in building construction has created major public health concerns for state governments. If asbestos is not thoroughly bound in cement, plaster, resin or some other stable material, it will flake and powder, releasing countless microscopic fibers into the air. Asbestos fibers penetrate deep into…

Interferometric fiber optic displacement sensor

DOEpatents

Farah, J.

1999-04-06

A method is presented to produce a change in the optical path length in the gap between two single mode optical fibers proportional to the lateral displacement of either fiber end normal to its axis. This is done with the use of refraction or diffraction at the interface between a guiding and non-guiding media to change the direction of propagation of the light in the gap. A method is also presented for laying a waveguide on a cantilever so that the displacement of the tip of the cantilever produces a proportional path length change in the gap by distancing the waveguide from the neutral axis of the cantilever. The fiber is supported as a cantilever or a waveguide is deposited on a micromachined cantilever and incorporated in an interferometer which is made totally on a silicon substrate with the use of integrated-optic technology. A resonant element in the form of a micro-bridge is incorporated in the ridge waveguide and produces a frequency output which is readily digitizeable and immune to laser frequency noise. Finally, monolithic mechanical means for phase modulation are provided on the same sensor substrate. This is done by vibrating the cantilever or micro-bridge either electrically or optically. 23 figs.

Interferometric fiber optic displacement sensor

DOEpatents

Farah, J.

1995-05-30

A method is presented to produce a change in the optical path length in the gap between two single mode optical fibers proportional to the lateral displacement of either fiber end normal to its axis. This is done with the use of refraction or diffraction at the interface between a guiding and non-guiding media to change the direction of propagation of the light in the gap. A method is also presented for laying a waveguide on a cantilever so that the displacement of the tip of the cantilever produces a proportional path length change in the gap by distancing the waveguide from the neutral axis of the cantilever. The fiber is supported as a cantilever or a waveguide is deposited on a micromachined cantilever and incorporated in an interferometer which is made totally on a silicon substrate with the use of integrated-optic technology. A resonant element in the form of a micro-bridge is incorporated in the ridge waveguide and produces a frequency output which is readily digitizeable and immune to laser frequency noise. Finally, monolithic mechanical means for phase modulation are provided on the same sensor substrate. This is done by vibrating the cantilever or micro-bridge either electrically or optically. 29 figs.

Interferometric fiber optic displacement sensor

DOEpatents

Farah, John

1995-01-01

A method is presented to produce a change in the optical path length in the gap between two single mode optical fibers proportional to the lateral displacement of either fiber end normal to its axis. This is done with the use of refraction or diffraction at the interface between a guiding and non-guiding media to change the direction of propagation of the light in the gap. A method is also presented for laying a waveguide on a cantilever so that the displacement of the tip of the cantilever produces a proportional path length change in the gap by distancing the waveguide from the neutral axis of the cantilever. The fiber is supported as a cantilever or a waveguide is deposited on a micromachined cantilever and incorporated in an interferometer which is made totally on a silicon substrate with the use of integrated-optic technology. A resonant element in the form of a micro-bridge is incorporated in the ridge waveguide and produces a frequency output which is readily digitizeable and immune to laser frequency noise. Finally, monolithic mechanical means for phase modulation are provided on the same sensor substrate. This is done by vibrating the cantilever or micro-bridge either electrically or optically.

Interferometric fiber optic displacement sensor

DOEpatents

Farah, John

1999-01-01

A method is presented to produce a change in the optical path length in the gap between two single mode optical fibers proportional to the lateral displacement of either fiber end normal to its axis. This is done with the use of refraction or diffraction at the interface between a guiding and non-guiding media to change the direction of propagation of the light in the gap. A method is also presented for laying a waveguide on a cantilever so that the displacement of the tip of the cantilever produces a proportional path length change in the gap by distancing the waveguide from the neutral axis of the cantilever. The fiber is supported as a cantilever or a waveguide is deposited on a micromachined cantilever and incorporated in an interferometer which is made totally on a silicon substrate with the use of integrated-optic technology. A resonant element in the form of a micro-bridge is incorporated in the ridge waveguide and produces a frequency output which is readily digitizeable and immune to laser frequency noise. Finally, monolithic mechanical means for phase modulation are provided on the same sensor substrate. This is done by vibrating the cantilever or micro-bridge either electrically or optically.

Fiber optic temperature sensor

NASA Technical Reports Server (NTRS)

Sawatari, Takeo (Inventor); Gaubis, Philip A. (Inventor)

2000-01-01

A fiber optic temperature sensor uses a light source which transmits light through an optical fiber to a sensor head at the opposite end of the optical fiber from the light source. The sensor head has a housing coupled to the end of the optical fiber. A metallic reflective surface is coupled to the housing adjacent the end of the optical fiber to form a gap having a predetermined length between the reflective surface and the optical fiber. A detection system is also coupled to the optical fiber which determines the temperature at the sensor head from an interference pattern of light which is reflected from the reflective surface.

Fiber optic temperature sensor

NASA Technical Reports Server (NTRS)

Sawatari, Takeo (Inventor); Gaubis, Philip A. (Inventor); Mattes, Brenton L. (Inventor); Charnetski, Clark J. (Inventor)

1999-01-01

A fiber optic temperature sensor uses a light source which transmits light through an optical fiber to a sensor head at the opposite end of the optical fiber from the light source. The sensor head has a housing coupled to the end of the optical fiber. A metallic reflective surface is coupled to the housing adjacent the end of the optical fiber to form a gap having a predetermined length between the reflective surface and the optical fiber. A detection system is also coupled to the optical fiber which determines the temperature at the sensor head from an interference pattern of light which is reflected from the reflective surface.

Optical fiber F-P magnetic field sensor based on magnetostrictive effect of magnetic fluid

NASA Astrophysics Data System (ADS)

Shi, Fuquan; Luo, Yan; Che, Jiajia; Ren, Zhijun; peng, Baojin

2018-07-01

magnetic field sensor of air-gap Fabry-Perot fiber interferometersis proposed based on magnetostrictive effect. The sensor is consisted of single-model fiber (SMF), air-gap, no-core fiber (NCF) and magnetic fluid. Those are sealed in the capillary, SMF and NCF are connect with air chamber and magnetic fluid column. With the presence of an external magnetic field, air chamber cavity length changes because of the magneto-volume variation of magnetic fluids. This situation causes a change in the optical path difference. Detection of the drift of interference spectrum leads to the detection of the change in magnetic field. When the magnetic field is parallel to the direction in which the capillary is placed, the sensitivity is 0.2347 nm/mT; when the magnetic fluid is perpendicular to the direction in which the capillary is placed, the sensitivity is 0.325 nm/http://mT.%20In.

Enhancement of acoustical performance of hollow tube sound absorber

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

Putra, Azma, E-mail: azma.putra@utem.edu.my; Khair, Fazlin Abd, E-mail: fazlinabdkhair@student.utem.edu.my; Nor, Mohd Jailani Mohd, E-mail: jai@utem.edu.my

This paper presents acoustical performance of hollow structures utilizing the recycled lollipop sticks as acoustic absorbers. The hollow cross section of the structures is arranged facing the sound incidence. The effects of different length of the sticks and air gap on the acoustical performance are studied. The absorption coefficient was measured using impedance tube method. Here it is found that improvement on the sound absorption performance is achieved by introducing natural kapok fiber inserted into the void between the hollow structures. Results reveal that by inserting the kapok fibers, both the absorption bandwidth and the absorption coefficient increase. For testmore » sample backed by a rigid surface, best performance of sound absorption is obtained for fibers inserted at the front and back sides of the absorber. And for the case of test sample with air gap, this is achieved for fibers introduced only at the back side of the absorber.« less

Enhancement of acoustical performance of hollow tube sound absorber

NASA Astrophysics Data System (ADS)

Putra, Azma; Khair, Fazlin Abd; Nor, Mohd Jailani Mohd

2016-03-01

This paper presents acoustical performance of hollow structures utilizing the recycled lollipop sticks as acoustic absorbers. The hollow cross section of the structures is arranged facing the sound incidence. The effects of different length of the sticks and air gap on the acoustical performance are studied. The absorption coefficient was measured using impedance tube method. Here it is found that improvement on the sound absorption performance is achieved by introducing natural kapok fiber inserted into the void between the hollow structures. Results reveal that by inserting the kapok fibers, both the absorption bandwidth and the absorption coefficient increase. For test sample backed by a rigid surface, best performance of sound absorption is obtained for fibers inserted at the front and back sides of the absorber. And for the case of test sample with air gap, this is achieved for fibers introduced only at the back side of the absorber.

Free space optics: a viable last-mile alternative

NASA Astrophysics Data System (ADS)

Willebrand, Heinz A.; Clark, Gerald R.

2001-10-01

This paper explores Free Space Optics (FSO) as an access technology in the last mile of metropolitan area networks (MANs). These networks are based in part on fiber-optic telecommunications infrastructure, including network architectures of Synchronous Optical Network (commonly referred to as SONET), the North American standard for synchronous data transmission; and Synchronous Digital Hierarchy (commonly referred to as SDH), the international standard and equivalent of SONET. Several converging forces have moved FSO beyond a niche technology for use only in local area networks (LANs) as a bridge connecting two facilities. FSO now allows service providers to cost effectively provide optical bandwidth for access networks and accelerate the extension of metro optical networks bridging what has been termed by industry experts as the optical dead zone. The optical dead zone refers to both the slowdown in capital investment in the short-term future and the actual connectivity gap that exists today between core metro optical networks and the access optical networks. Service providers have built extensive core and minimal metro networks but have not yet provided optical bandwidth to the access market largely due to the non-compelling economics to bridge the dead zone with fiber. Historically, such infrastructure build-out slowdowns have been blamed on a combination of economics, time-to-market constraints and limited technology options. However, new technology developments and market acceptance of FSO give service providers a new cost-effective alternative to provide high-bandwidth services with optical bandwidth in the access networks. Merrill Lynch predicts FSO will grow into a $2 billion market by 2005. The drivers for this market are a mere 5%- 6% penetration of fiber to business buildings; cost effective solution versus RF or fiber; and significant capacity which can only be matched by a physical fiber link, Merrill Lynch reports. This paper will describe FSO technology, its capabilities and its limitations. The paper will investigate how FSO technology has evolved to its current stage for deployment in MANs, LANs, wireless backhaul and metropolitan network extensions - applications that fall within the category of last mile. The paper will address the market, drivers and the adoption of FSO, plus provide a projection of future FSO technology, based on today's product roadmaps. The paper concludes with a summary of findings and recommendations.

Asbestos Removal in the Construction Industry.

DTIC Science & Technology

1991-01-01

a lower strength lighter building panel. 5.3.3 Sprayed Coatings Mineral wool fiber and vermiculite have replaced asbestos in sprayed coating...wearing resistance and non- slip properties in floor tiles. Glass or mineral wool fibers may be used as alternative fibers, but make for a brittle...asbestos, for many applications, is millboard made from aluminosilicate fibers or mineral wool fibers. These fibers are bonded with a high temperature

Assessment of Carbon Fiber Electrical Effects

NASA Technical Reports Server (NTRS)

1980-01-01

The risks associated with the use of carbon fiber composites in civil aircraft are discussed along with the need for protection of civil aircraft equipment from fire-released carbon fibers. The size and number of carbon fibers released in civil aircraft crash fires, the downwind dissemination of the fibers, their penetration into buildings and equipment, and the vulnerability of electrical/electronic equipment to damage by the fibers are assessed.

Gas-phase optical fiber photocatalytic reactors for indoor air application: a preliminary study on performance indicators

NASA Astrophysics Data System (ADS)

Palmiste, Ü.; Voll, H.

2017-10-01

The development of advanced air cleaning technologies aims to reduce building energy consumption by reduction of outdoor air flow rates while keeping the indoor air quality at an acceptable level by air cleaning. Photocatalytic oxidation is an emerging technology for gas-phase air cleaning that can be applied in a standalone unit or a subsystem of a building mechanical ventilation system. Quantitative information on photocatalytic reactor performance is required to evaluate the technical and economic viability of the advanced air cleaning by PCO technology as an energy conservation measure in a building air conditioning system. Photocatalytic reactors applying optical fibers as light guide or photocatalyst coating support have been reported as an approach to address the current light utilization problems and thus, improve the overall efficiency. The aim of the paper is to present a preliminary evaluation on continuous flow optical fiber photocatalytic reactors based on performance indicators commonly applied for air cleaners. Based on experimental data, monolith-type optical fiber reactor performance surpasses annular-type optical fiber reactors in single-pass removal efficiency, clean air delivery rate and operating cost efficiency.

Coagulation measurement from whole blood using vibrating optical fiber in a disposable cartridge

NASA Astrophysics Data System (ADS)

Yaraş, Yusuf Samet; Gündüz, Ali Bars; Saǧlam, Gökhan; Ölçer, Selim; Civitçi, Fehmi; Baris, İbrahim; Yaralioǧlu, Göksenin; Urey, Hakan

2017-11-01

In clinics, blood coagulation time measurements are performed using mechanical measurements with blood plasma. Such measurements are challenging to do in a lab-on-a-chip (LoC) system using a small volume of whole blood. Existing LoC systems use indirect measurement principles employing optical or electrochemical methods. We developed an LoC system using mechanical measurements with a small volume of whole blood without requiring sample preparation. The measurement is performed in a microfluidic channel where two fibers are placed inline with a small gap in between. The first fiber operates near its mechanical resonance using remote magnetic actuation and immersed in the sample. The second fiber is a pick-up fiber acting as an optical sensor. The microfluidic channel is engineered innovatively such that the blood does not block the gap between the vibrating fiber and the pick-up fiber, resulting in high signal-to-noise ratio optical output. The control plasma test results matched well with the plasma manufacturer's datasheet. Activated-partial-thromboplastin-time tests were successfully performed also with human whole blood samples, and the method is proven to be effective. Simplicity of the cartridge design and cost of readily available materials enable a low-cost point-of-care device for blood coagulation measurements.

Coagulation measurement from whole blood using vibrating optical fiber in a disposable cartridge.

PubMed

Yaraş, Yusuf Samet; Gündüz, Ali Bars; Sağlam, Gökhan; Ölçer, Selim; Civitçi, Fehmi; Baris, İbrahim; Yaralioğlu, Göksenin; Urey, Hakan

2017-11-01

In clinics, blood coagulation time measurements are performed using mechanical measurements with blood plasma. Such measurements are challenging to do in a lab-on-a-chip (LoC) system using a small volume of whole blood. Existing LoC systems use indirect measurement principles employing optical or electrochemical methods. We developed an LoC system using mechanical measurements with a small volume of whole blood without requiring sample preparation. The measurement is performed in a microfluidic channel where two fibers are placed inline with a small gap in between. The first fiber operates near its mechanical resonance using remote magnetic actuation and immersed in the sample. The second fiber is a pick-up fiber acting as an optical sensor. The microfluidic channel is engineered innovatively such that the blood does not block the gap between the vibrating fiber and the pick-up fiber, resulting in high signal-to-noise ratio optical output. The control plasma test results matched well with the plasma manufacturer's datasheet. Activated-partial-thromboplastin-time tests were successfully performed also with human whole blood samples, and the method is proven to be effective. Simplicity of the cartridge design and cost of readily available materials enable a low-cost point-of-care device for blood coagulation measurements. (2017) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

Automated determination of fibrillar structures by simultaneous model building and fiber diffraction refinement.

PubMed

Potrzebowski, Wojciech; André, Ingemar

2015-07-01

For highly oriented fibrillar molecules, three-dimensional structures can often be determined from X-ray fiber diffraction data. However, because of limited information content, structure determination and validation can be challenging. We demonstrate that automated structure determination of protein fibers can be achieved by guiding the building of macromolecular models with fiber diffraction data. We illustrate the power of our approach by determining the structures of six bacteriophage viruses de novo using fiber diffraction data alone and together with solid-state NMR data. Furthermore, we demonstrate the feasibility of molecular replacement from monomeric and fibrillar templates by solving the structure of a plant virus using homology modeling and protein-protein docking. The generated models explain the experimental data to the same degree as deposited reference structures but with improved structural quality. We also developed a cross-validation method for model selection. The results highlight the power of fiber diffraction data as structural constraints.

Arrangement for connecting a fiber-reinforced plastic pipe to a stainless steel flange

DOEpatents

Allais, Arnaud [D-30625 Hannover, DE; Hoffmann, Ernst [D-30855 Langenhagen, DE

2008-02-05

Arrangement for connecting a fiber-reinforced plastic pipe (18) to a stainless steel flange (12, 16), in which the end of the fiber-reinforced plastic pipe (18) is accommodated in a ring-shaped groove (12a, 16a) in the flange (12, 16), the groove conforming to the dimensions of the fiber-reinforced plastic pipe (18), where the gap remaining between the end of the fiber-reinforced plastic pipe (18) and the ring-shaped groove (12a, 16a) is filled with a sealant (19).

Apparatus and Method for Measuring Strain in Optical Fibers using Rayleigh Scatter

NASA Technical Reports Server (NTRS)

Froggatt, Mark E. (Inventor); Moore, Jason P. (Inventor)

2003-01-01

An apparatus and method for measuring strain in an optical fiber using the spectral shift of Rayleigh scattered light. The interference pattern produced by an air gap reflector and backscattered radiation is measured. Using Fourier Transforms, the spectrum of any section of fiber can be extracted. Cross correlation with an unstrained measurement produces a correlation peak. The location of the correlation peak indicates the strain level in the selected portion of optical fiber.

Fiber optic sensor based on Mach-Zehnder interferometer for securing entrance areas of buildings

NASA Astrophysics Data System (ADS)

Nedoma, Jan; Fajkus, Marcel; Martinek, Radek; Mec, Pavel; Novak, Martin; Bednarek, Lukas; Vasinek, Vladimir

2017-10-01

Authors of this article focused on the utilization of fiber optic sensors based on interferometric measurements for securing entrance areas of buildings such as windows and doors. We described the implementation of the fiber-optic interferometer (type Mach-Zehnder) into the window frame or door, sensor sensitivity, analysis of the background noise and methods of signal evaluation. The advantage of presented solution is the use of standard telecommunication fiber standard G.652.D, high sensitivity, immunity of sensor to electromagnetic interference (EMI) and passivity of the sensor regarding power supply. Authors implemented the Graphical User Interface (GUI) which offers the possibility of remote monitoring presented sensing solution.

Flexural strength using Steel Plate, Carbon Fiber Reinforced Polymer (CFRP) and Glass Fiber Reinforced Polymer (GFRP) on reinforced concrete beam in building technology

NASA Astrophysics Data System (ADS)

Tarigan, Johannes; Patra, Fadel Muhammad; Sitorus, Torang

2018-03-01

Reinforced concrete structures are very commonly used in buildings because they are cheaper than the steel structures. But in reality, many concrete structures are damaged, so there are several ways to overcome this problem, by providing reinforcement with Fiber Reinforced Polymer (FRP) and reinforcement with steel plates. Each type of reinforcements has its advantages and disadvantages. In this study, researchers discuss the comparison between flexural strength of reinforced concrete beam using steel plates and Fiber Reinforced Polymer (FRP). In this case, the researchers use Carbon Fiber Reinforced Polymer (CFRP) and Glass Fiber Reinforced Polymer (GFRP) as external reinforcements. The dimension of the beams is 15 x 25 cm with the length of 320 cm. Based on the analytical results, the strength of the beam with CFRP is 1.991 times its initial, GFRP is 1.877 times while with the steel plate is 1.646 times. Based on test results, the strength of the beam with CFRP is 1.444 times its initial, GFRP is 1.333 times while the steel plate is 1.167 times. Based on these test results, the authors conclude that beam with CFRP is the best choice for external reinforcement in building technology than the others.

[Development and perspective of bio-based chemical fiber industry].

PubMed

Li, Zengjun

2016-06-25

Bio-based fiber is environment friendly, reproducible, easily biodegradable. Therefore, rapid development of bio-based fiber industry is an obvious in progress to replace petrochemical resources, develop sustainable economy, build resource saving and environment friendly society. This article describes the current development of bio-based fiber industry, analyzes existing problems, indicates the trends and objectives of bio-based fiber materials technology innovation and recommends developing bio-based fibers industry of our country.

Role of interfacial thermal barrier in the transverse thermal conductivity of uniaxial SiC fiber-reinforced reaction bonded silicon nitride

NASA Technical Reports Server (NTRS)

Bhatt, H.; Donaldson, K. Y.; Hasselman, D. P. H.; Bhatt, R. T.

1992-01-01

The transverse thermal conductivity of reaction-bonded Si3N4 is significantly affected by an interfacial barrier at the interface formed with SiC reinforcing fibers. A comparative study of composites with and without reinforcing-fiber carbon coatings found the coating to reduce effective thermal conductivity by a factor of about 2; this, however, is partially due to a thermal expansion-mismatch gap between fiber and matrix. HIPing of composites with coated fibers led to an enhancement of thermal conductivity via improved interfacial thermal contact and greater grain size and crystallinity of the fibers.

The usage of carbon fiber reinforcement polymer and glass fiber reinforcement polymer for retrofit technology building

NASA Astrophysics Data System (ADS)

Tarigan, Johannes; Meka, Randi; Nursyamsi

2018-03-01

Fiber Reinforcement Polymer has been used as a material technology since the 1970s in Europe. Fiber Reinforcement Polymer can reinforce the structure externally, and used in many types of buildings like beams, columns, and slabs. It has high tensile strength. Fiber Reinforcement Polymer also has high rigidity and strength. The profile of Fiber Reinforcement Polymer is thin and light, installation is simple to conduct. One of Fiber Reinforcement Polymer material is Carbon Fiber Reinforcement Polymer and Glass Fiber Reinforcement Polymer. These materials is tested when it is installed on concrete cylinders, to obtain the comparison of compressive strength CFRP and GFRP. The dimension of concrete is diameter of 15 cm and height of 30 cm. It is amounted to 15 and divided into three groups. The test is performed until it collapsed to obtain maximum load. The results of research using CFRP and GFRP have shown the significant enhancement in compressive strength. CFRP can increase the compressive strength of 26.89%, and GFRP of 14.89%. For the comparison of two materials, CFRP is more strengthening than GFRP regarding increasing compressive strength. The usage of CFRP and GFRP can increase the loading capacity.

Evolution of Texture from a Single Crystal Ti-6Al-4V Substrate During Electron Beam Directed Energy Deposition

NASA Astrophysics Data System (ADS)

Butler, Todd M.; Brice, Craig A.; Tayon, Wesley A.; Semiatin, S. Lee; Pilchak, Adam L.

2017-10-01

Additive manufacturing of Ti-6Al-4V commonly produces 〈001〉 β -fiber textures aligned with the build direction. We have performed wire-feed electron beam directed energy deposition on the {112} β plane of a single prior β-grain. The build initially grew epitaxially from the substrate with the preferred 〈001〉 growth direction significantly angled away from the build direction. However, continued layer deposition drove the formation of a 〈001〉 β -fiber texture aligned with the build direction and the direction of the strongest thermal gradient.

Building Blueprints: Looking Toward the Future.

ERIC Educational Resources Information Center

College Planning & Management, 2001

2001-01-01

Highlights Kent State University's (Ohio) conversion of its physical education building to a technology building that features fiber optics and advanced cabling systems. Photos and a floor plan are included. (GR)

Machine Tests Optical Fibers In Flexure

NASA Technical Reports Server (NTRS)

Darejeh, Hadi; Thomas, Henry; Delcher, Ray

1993-01-01

Machine repeatedly flexes single optical fiber or cable or bundle of optical fibers at low temperature. Liquid nitrogen surrounds specimen as it is bent back and forth by motion of piston. Machine inexpensive to build and operate. Tests under repeatable conditions so candidate fibers, cables, and bundles evaluated for general robustness before subjected to expensive shock and vibration tests.

Summary record of presentations to the Federal Telecommunication Standards Committee/Fiber optics task group

NASA Astrophysics Data System (ADS)

Hanson, A. G.

1987-03-01

The learning experience of a group of Federal-agency planners who face upgrading or augmenting existing on-premises communication systems and building wiring is documented. In July 1984, an interagency Fiber Optics Task Group was formed under the aegis of the Federal Telecommunication Standards Committee to study on-premises distribution systems, with emphasis on optical fiber implementation, sharing mutual problems and potential solutions for them. Chronological summary records of technical content of 11 Task Group meetings through September 1986 are summarized. Also condensed are the engineering presentations to the Task Group by industry on applicable state-of-the-art technology, including local area networks, private automatic branch exchanges, building wiring architecture, and optic fiber systems and components.

BREAST CANCER-INDUCED BONE REMODELING, SKELETAL PAIN AND SPROUTING OF SENSORY NERVE FIBERS

PubMed Central

Bloom, Aaron P.; Jimenez-Andrade, Juan M.; Taylor, Reid N.; Castañeda-Corral, Gabriela; Kaczmarska, Magdalena J.; Freeman, Katie T.; Coughlin, Kathleen A.; Ghilardi, Joseph R.; Kuskowski, Michael A.; Mantyh, Patrick W.

2011-01-01

Breast cancer metastasis to bone is frequently accompanied by pain. What remains unclear is why this pain tends to become more severe and difficult to control with disease progression. Here we test the hypothesis that with disease progression sensory nerve fibers that innervate the breast cancer bearing bone undergo a pathological sprouting and reorganization, which in other non-malignant pathologies has been shown to generate and maintain chronic pain. Injection of human breast cancer cells (MDA-MB-231-BO) into the femoral intramedullary space of female athymic nude mice induces sprouting of calcitonin gene-related peptide (CGRP+) sensory nerve fibers. Nearly all CGRP+ nerve fibers that undergo sprouting also co-express tropomyosin receptor kinase A (TrkA+) and growth associated protein-43 (GAP43+). This ectopic sprouting occurs in periosteal sensory nerve fibers that are in close proximity to breast cancer cells, tumor-associated stromal cells and remodeled cortical bone. Therapeutic treatment with an antibody that sequesters nerve growth factor (NGF), administered when the pain and bone remodeling were first observed, blocks this ectopic sprouting and attenuates cancer pain. The present data suggest that the breast cancer cells and tumor-associated stromal cells express and release NGF, which drives bone pain and the pathological reorganization of nearby CGRP+ / TrkA+ / GAP43+ sensory nerve fibers. PMID:21497141

Rigid polyurethane foam – kenaf core composites for structural applications

USDA-ARS?s Scientific Manuscript database

Kenaf (Hibiscus cannabinus L.) is a fast growing summer annual crop with numerous commercial applications (fibers, biofuels, bioremediation, paper pulp, building materials, cover crops, and livestock forages). The stalks of the kenaf plants contain two distinct fiber types, bast and core fibers. The...

Fiber-based laser MOPA transmitter packaging for space environment

NASA Astrophysics Data System (ADS)

Stephen, Mark; Yu, Anthony; Chen, Jeffrey; Numata, Kenji; Wu, Stewart; Gonzales, Brayler; Han, Lawrence; Fahey, Molly; Plants, Michael; Rodriguez, Michael; Allan, Graham; Abshire, James; Nicholson, Jeffrey; Hariharan, Anand; Mamakos, William; Bean, Brian

2018-02-01

NASA's Goddard Space Flight Center has been developing lidar to remotely measure CO2 and CH4 in the Earth's atmosphere. The ultimate goal is to make space-based satellite measurements with global coverage. We are working on maturing the technology readiness of a fiber-based, 1.57-micron wavelength laser transmitter designed for use in atmospheric CO2 remote-sensing. To this end, we are building a ruggedized prototype to demonstrate the required power and performance and survive the required environment. We are building a fiber-based master oscillator power amplifier (MOPA) laser transmitter architecture. The laser is a wavelength-locked, single frequency, externally modulated DBR operating at 1.57-micron followed by erbium-doped fiber amplifiers. The last amplifier stage is a polarization-maintaining, very-large-mode-area fiber with 1000 μm2 effective area pumped by a Raman fiber laser. The optical output is single-frequency, one microsecond pulses with >450 μJ pulse energy, 7.5 KHz repetition rate, single spatial mode, and < 20 dB polarization extinction.

SU-E-T-777: Use of Tennis Racket and Air Gap Between the Body and Carbon Fiber Couch for Skin Sparing in Radiation Therapy of Prone Breast

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

Lief, E

2015-06-15

Purpose: To reduce the skin dose from the carbon fiber couch scatter in radiation treatment of breast cancer in the prone position. If this issue is not addressed, the prone breast touching the solid carbon fiber couch can absorb significant dose to the skin and cause the skin reaction. Methods: 1. Use of “tennis racket” instead of the solid couch. To check this hypothesis, we measured the dose at the depth of 5 mm in solid water phantom placed on the couch, using a Farmer chamber. A plan for a patient with 6MV beams, gantry angles of 113 and 286more » degrees Varian scale was used. It was found that treatment with “tennis racket” instead of the solid carbon fiber couch reduces the surface dose by 5–7%, depending on the beam direction. 2. Use of the air gap between the couch and the body was analyzed using radiochromic film on the surface of the solid water phantom 10 cm thick. Initially the phantom was placed on the couch with the film sandwiched in between. Two fields at the angles of 135 and 315 degrees were used. The measurements were repeated for the air gap of 2 and 5 cm and 6 and 15 MV beams. Results: It was found that a 2-cm gap decreased the surface dose by 3% for a 6 MV beam and by 5.5% for a 15 MV beam. A 5-cm gap reduced the dose by 9% for 6 MV and 13.5% for 15 MV. Conclusion: Use of both methods (combined if possible) can significantly reduce the surface dose in radiation therapy of the prone breast and possible skin reaction. We plan to explore dependence of the dose reduction upon the angle of incidence.« less

New CATV fiber-to-the-subscriber architectures

NASA Astrophysics Data System (ADS)

Kim, Gary

1991-01-01

Although the cable television industry has seriously proposed the widespread use of optical fiber technology as the foundation of its networks only since 1988 an important financial watershed already has been reached. Based on stunningly rapid AM technology developments and new research by industry engineers the CATV industry has already reached the point where building new optical trunk is cheaper than building conventional coaxial cable plant. Although as recently as 1988 it might have seemed preposterous to suggest that the financial crossover point between optical media and copper media would soon be reached that indeed has occurred. Using a topology dubbed the " fiber trunk and feeder engineers at American Television Communications the second-largest U. S. CATV operator have demonstrated that it is currently feasible to build new optical fiber trunking networks at costs equal to or less than conventional 450-MHz coaxial cable plant. Installation of the first such network already is underway and it is expected that the significant change in fiber economics will further spur the already-heady pace of fiber introduction in the CATV industry. That in turn will create new types of networks with topologies resembling telephone " star" networks more than conventional " tree-and-branch" systems. The new optically-based networks will be far more reliable more flexible and better adapted to signal switching than conventional CATV networks have been. Although the new networks will be put into place

A probabilistic analysis of electrical equipment vulnerability to carbon fibers

NASA Technical Reports Server (NTRS)

Elber, W.

1980-01-01

The statistical problems of airborne carbon fibers falling onto electrical circuits were idealized and analyzed. The probability of making contact between randomly oriented finite length fibers and sets of parallel conductors with various spacings and lengths was developed theoretically. The probability of multiple fibers joining to bridge a single gap between conductors, or forming continuous networks is included. From these theoretical considerations, practical statistical analyses to assess the likelihood of causing electrical malfunctions was produced. The statistics obtained were confirmed by comparison with results of controlled experiments.

Bamboo fiberboards and attapulgite : does it lead to an improvement of humidity control in buildings?

NASA Astrophysics Data System (ADS)

Nguyen, D. M.; Grillet, A. C.; Goldin, T.; Hanh Diep, T. M.; Woloszyn, M.

2018-04-01

In order to save energy used to heat or cool buildings and to improve the inhabitants comfort, control of humidity inside buildings must be improved. This can be done by using buffering materials able to absorb and release moisture when necessary. Natural fibers and mineral absorbent are good candidates to manufacture such materials. The aim of this research is to mix bamboo fibers with attapulgite to evaluate the influence of this mineral absorbent on the hygric behavior of the fiberboards. The hygric properties are slightly improved by the attapulgite and thus bamboo fiberboards can be used as building insulation materials able to participate to the indoor moisture control.

Effect of coupling agents on the weathering characteristics of bio-fiber composites

USDA-ARS?s Scientific Manuscript database

Bio-fiber polymer composites (BFPC) are composite materials made from a thermoplastic or thermoset resin (substrate) with cellulosic fibers as fillers or reinforcement. BFPC have shown a significant growth in the last decade as a building product, automotive parts, and landscaping products. BFPC com...

Use of rubble from building demolition in mortars.

PubMed

Corinaldesi, V; Giuggiolini, M; Moriconi, G

2002-01-01

Because of increasing waste production and public concerns about the environment, it is desirable to recycle materials from building demolition. If suitably selected, ground, cleaned and sieved in appropriate industrial crushing plants, these materials can be profitably used in concrete. Nevertheless, the presence of masonry instead of concrete rubble is particularly detrimental to the mechanical performance and durability of recycled-aggregate concrete and the same negative effect is detectable when natural sand is replaced by fine recycled aggregate fraction. An alternative use of both masonry rubble and fine recycled material fraction could be in mortars. These could contain either recycled instead of natural sand or powder obtained by bricks crushing as partial cement substitution. In particular, attention is focused on the modification that takes place when either polypropylene or stainless steel fibers are added to these mortars. Polypropylene fibers are added in order to reduce shrinkage of mortars, stainless steel fibers for improving their flexural strength. The combined use of polypropylene fibers and fine recycled material from building demolition could allow the preparation of mortars showing good performance, in particular when coupled with bricks. Furthermore, the combined use of stainless steel fibers and mortars containing brick powder seems to be an effective way to guarantee a high flexural strength.

Effect of combined extrusion parameters on mechanical properties of basalt fiber-reinforced plastics based on polypropylene

NASA Astrophysics Data System (ADS)

Bashtannik, P. I.; Ovcharenko, V. G.; Boot, Yu. A.

1997-11-01

Basalt fibers are efficient reinforcing fillers for polypropylene because they increase both the mechanical and the tribotechnical properties of composites. Basalt fibers can compete with traditional fillers (glass and asbestos fibers) of polypropylene with respect to technological, economic, and toxic properties. The effect of technological parameters of producing polypropylene-based basalt fiber-reinforced plastics (BFRPs) by combined extrusion on their mechanical properties has been investigated. The extrusion temperature was found to be the main parameter determining the mechanical properties of the BFRPs. With temperature growth from 180 to 240°C, the residual length of the basalt fibers in the composite, as well as the adhesive strength of the polymer-fiber system, increased, while the composite defectiveness decreased. The tensile strength and elastic modulus increased from 35 to 42 MPa and 3.2 to 4.2 GPa, respectively. At the same time, the growth in composite solidity led to its higher brittleness. Thus, a higher temperature of extrusion allows us to produce materials which can be subjected to tensile and bending loads, while the materials produced at a lower temperature of extrusion are impact stable. The effect of the gap size between the extruder body and moving disks on the mechanical properties of the BFRPs is less significant than that of temperature. An increase of the gap size from 2 to 8 mm improves the impregnation quality of the fibers, but the extruder productivity diminishes. The possibility of controling the properties of reinforced polypropylene by varying the technological parameters of combined extrusion is shown. The polypropylene-based BFRPs produced by the proposed method surpass the properties of glass and asbestos fiber-reinforced plastics.

Filling America's fiber intake gap: Summary of a roundtable to probe realistic solutions with a focus on grain-based foods

USDA-ARS?s Scientific Manuscript database

Current fiber intakes are alarmingly low, with long-term implications for public health related to risk of coronary heart disease, stroke, hypertension, certain gastrointestinal disorders, obesity, and the continuum of metabolic dysfunctions including prediabetes and type 2 diabetes. With more than ...

Experimental Analysis of Steel Beams Subjected to Fire Enhanced by Brillouin Scattering-Based Fiber Optic Sensor Data.

PubMed

Bao, Yi; Chen, Yizheng; Hoehler, Matthew S; Smith, Christopher M; Bundy, Matthew; Chen, Genda

2017-01-01

This paper presents high temperature measurements using a Brillouin scattering-based fiber optic sensor and the application of the measured temperatures and building code recommended material parameters into enhanced thermomechanical analysis of simply supported steel beams subjected to combined thermal and mechanical loading. The distributed temperature sensor captures detailed, nonuniform temperature distributions that are compared locally with thermocouple measurements with less than 4.7% average difference at 95% confidence level. The simulated strains and deflections are validated using measurements from a second distributed fiber optic (strain) sensor and two linear potentiometers, respectively. The results demonstrate that the temperature-dependent material properties specified in the four investigated building codes lead to strain predictions with less than 13% average error at 95% confidence level and that the Europe building code provided the best predictions. However, the implicit consideration of creep in Europe is insufficient when the beam temperature exceeds 800°C.

Active Q switching of a fiber laser with a microsphere resonator

NASA Astrophysics Data System (ADS)

Kieu, Khanh; Mansuripur, Masud

2006-12-01

We propose and demonstrate an active Q-switched fiber laser using a high-Q microsphere resonator as the Q-switching element. The laser cavity consists of an Er-doped fiber as the gain medium, a glass microsphere reflector (coupled through a fiber taper) at one end of the cavity, and a fiber Bragg grating reflector at the other end. The reflectivity of the microsphere is modulated by changing the gap between the microsphere and the fiber taper. Active Q switching is realized by oscillating the microsphere in and out of contact with the taper. Using this novel technique, we have obtained giant pulses (maximum peak power ˜102W, duration ˜160ns) at a low pump-power threshold (˜3mW).

Practical Aspects of Access Network Indoor Extensions Using Multimode Glass and Plastic Optical Fibers

NASA Astrophysics Data System (ADS)

Keiser, Gerd; Liu, Hao-Yu; Lu, Shao-Hsi; Devi Pukhrambam, Puspa

2012-07-01

Low-cost multimode glass and plastic optical fibers are attractive for high-capacity indoor telecom networks. Many existing buildings already have glass multimode fibers installed for local area network applications. Future indoor applications will use combinations of glass multimode fibers with plastic optical fibers that have low losses in the 850-nm-1,310-nm range. This article examines real-world link losses when randomly interconnecting glass and plastic fiber segments having factory-installed connectors. Potential interconnection issues include large variations in connector losses among randomly selected fiber segments, asymmetric link losses in bidirectional links, and variations in bandwidths among different types of fibers.

Optical gateway for intelligent buildings: a new open-up window to the optical fibre sensors market?

NASA Astrophysics Data System (ADS)

Fernandez-Valdivielso, Carlos; Matias, Ignacio R.; Arregui, Francisco J.; Bariain, Candido; Lopez-Amo, Manuel

2004-06-01

This paper presents the first optical fiber sensor gateway for integrating these special measurement devices in Home Automation Systems, concretely in those buildings that use the KNX European Intelligent Buildings Standard.

Airflow Resistance of Loose-Fill Mineral Fiber Insulations in Retrofit Applications

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

Schumacher, C. J.; Fox, M. J.; Lstiburek, J.

2015-02-01

This report expands on Building America Report 1109 by applying the experimental apparatus and test method to dense-pack retrofit applications using mineral fiber insulation materials. Three fiber glass insulation materials and one stone wool insulation material were tested, and the results compared to the cellulose results from the previous study.

100 GHz ultra-wideband (UWB) fiber-to-the-antenna (FTTA) system for in-building and in-home networks.

PubMed

Chow, C W; Kuo, F M; Shi, J W; Yeh, C H; Wu, Y F; Wang, C H; Li, Y T; Pan, C L

2010-01-18

Fiber-to-the-antenna (FTTA) system can be a cost-effective technique for distributing high frequency signals from the head-end office to a number of remote antenna units via passive optical splitter and propagating through low-loss and low-cost optical fibers. Here, we experimentally demonstrate an optical ultra-wideband (UWB) - impulse radio (IR) FTTA system for in-building and in-home applications. The optical UWB-IR wireless link is operated in the W-band (75 GHz - 110 GHz) using our developed near-ballistic unitraveling-carrier photodiode based photonic transmitter (PT) and a 10 GHz mode-locked laser. 2.5 Gb/s UWB-IR FTTA systems with 1,024 high split-ratio and transmission over 300 m optical fiber are demonstrated using direct PT modulation.

Feedback Information and Analysis for Microprocessor Controlled Muscle Stimulation.

DTIC Science & Technology

1981-12-01

muscle into fiberous tissue (Guyton, 1976) is not inevitable. The contractile power can be preserved and fiberous build-up reduced by electrical... isometric tension, velocity of contraction and coordination of movement, all with minimally induced muscle fatigue. The work of Petrofsky and Phillips... muscle . Each muscle fiber is innervated by only a single nerve, but a single motor nerve fiber branches to as many as thousands of different muscle

Polarized emission from CsPbBr3 nanowire embedded-electrospun PU fibers

NASA Astrophysics Data System (ADS)

Güner, Tuğrul; Topçu, Gökhan; Savacı, Umut; Genç, Aziz; Turan, Servet; Sari, Emre; Demir, Mustafa M.

2018-04-01

Interest in all-inorganic halide perovskites has been increasing dramatically due to their high quantum yield, band gap tunability, and ease of fabrication in compositional and geometric diversity. In this study, we synthesized several hundreds of nanometer long and ˜4 nm thick CsPbBr 3 nanowires (NWs). They were then integrated into electrospun polyurethane (PU) fibers to examine the polarization behavior of the composite fiber assembly. Aligned electrospun fibers containing CsPbBr 3 NWs showed a remarkable increase in the degree of polarization from 0.17-0.30. This combination of NWs and PU fibers provides a promising composite material for various applications such as optoelectronic devices and solar cells.

Prebiotics, Fermentable Dietary Fiber, and Health Claims.

PubMed

Delcour, Jan A; Aman, Per; Courtin, Christophe M; Hamaker, Bruce R; Verbeke, Kristin

2016-01-01

Since the 1970s, the positive effects of dietary fiber on health have increasingly been recognized. The collective term "dietary fiber" groups structures that have different physiologic effects. Since 1995, some dietary fibers have been denoted as prebiotics, implying a beneficial physiologic effect related to increasing numbers or activity of the gastrointestinal microbiota. Given the complex composition of the microbiota, the demonstration of such beneficial effects is difficult. In contrast, an exploration of the metabolites of dietary fiber formed as a result of its fermentation in the colon offers better perspectives for providing mechanistic links between fiber intake and health benefits. Positive outcomes of such studies hold the promise that claims describing specific health benefits can be granted. This would help bridge the "fiber gap"-that is, the considerable difference between recommended and actual fiber intakes by the average consumer. © 2016 American Society for Nutrition.

Optimization of GRIN lenses coupling system for twin-core fiber interconnection with single core fibers

NASA Astrophysics Data System (ADS)

Chen, Gongdai; Deng, Hongchang; Yuan, Libo

2018-07-01

We aim at a more compact, flexible, and simpler core-to-fiber coupling approach, optimal combinations of two graded refractive index (GRIN) lenses have been demonstrated for the interconnection between a twin-core single-mode fiber and two single-core single-mode fibers. The optimal two-lens combinations achieve an efficient core-to-fiber separating coupling and allow the fibers and lenses to coaxially assemble. Finally, axial deviations and transverse displacements of the components are discussed, and the latter increases the coupling loss more significantly. The gap length between the two lenses is designed to be fine-tuned to compensate for the transverse displacement, and the good linear compensation relationship contributes to the device manufacturing. This approach has potential applications in low coupling loss and low crosstalk devices without sophisticated alignment and adjustment, and enables the channel separating for multicore fibers.

One-Dimensional Model for the Ultrasonic Response of Resin-Filled Gaps in Automated Tape Layup Composites

NASA Technical Reports Server (NTRS)

Johnston, Patrick H.; Juarez, Peter D.

2017-01-01

Automated tow placement has become a widely used fabrication technique, especially for large aerospace structures. Robotic heads lay down strips (tows) of preimpregnated fiber along programmed paths. The intention is to lay adjacent tows abutted to one another, but sometimes a gap is left between a tow and the previously-placed tow. If a tow gap exists, it fills with resin during cure, forming a fiber-free volume. In immersion ultrasonic pulse-echo measurements of a cured laminate, the gap can be observed to produce a noticeable echo, without significantly attenuating the back-wall reflection of the laminate. To understand this behavior, we considered a one dimensional model of the composite laminate, with a thin layer having the ultrasonic sound speed and density of neat resin, sandwiched between two layers of material having the sound speed and density of fiber-reinforced composite and surrounded on both sides by water. Neglecting attenuation, we considered the transmission and reflection coefficients of each interface, as well as that of the thin resin layer. Using the initial water/composite reflection as a reference, we computed the relative magnitude of the back surface/water reflection in the presence and in the absence of a resin-only layer, as well as the relative magnitude of the reflection arising from a thin resin layer in composite. While the one-dimensional model did not fully match the measurements, it did qualitatively explain the observed behavior.

Application of Negative Curvature Hollow-Core Fiber in an Optical Fiber Sensor Setup for Multiphoton Spectroscopy

PubMed Central

Stawska, Hanna Izabela; Mazur, Leszek Mateusz; Kosolapov, Alexey; Kolyadin, Anton; Bereś-Pawlik, Elżbieta

2017-01-01

In this paper, an application of negative curvature hollow core fiber (NCHCF) in an all-fiber, multiphoton fluorescence sensor setup is presented. The dispersion parameter (D) of this fiber does not exceed the value of 5 ps/nm × km across the optical spectrum of (680–750) nm, making it well suited for the purpose of multiphoton excitation of biological fluorophores. Employing 1.5 m of this fiber in a simple, all-fiber sensor setup allows us to perform multiphoton experiments without any dispersion compensation methods. Multiphoton excitation of nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD) with this fiber shows a 6- and 9-fold increase, respectively, in the total fluorescence signal collected when compared with the commercial solution in the form of a hollow-core photonic band gap fiber (HCPBF). To the author’s best knowledge, this is the first time an NCHCF was used in an optical-fiber sensor setup for multiphoton fluorescence experiments. PMID:28984838

Application of Negative Curvature Hollow-Core Fiber in an Optical Fiber Sensor Setup for Multiphoton Spectroscopy.

PubMed

Popenda, Maciej Andrzej; Stawska, Hanna Izabela; Mazur, Leszek Mateusz; Jakubowski, Konrad; Kosolapov, Alexey; Kolyadin, Anton; Bereś-Pawlik, Elżbieta

2017-10-06

In this paper, an application of negative curvature hollow core fiber (NCHCF) in an all-fiber, multiphoton fluorescence sensor setup is presented. The dispersion parameter (D) of this fiber does not exceed the value of 5 ps/nm × km across the optical spectrum of (680-750) nm, making it well suited for the purpose of multiphoton excitation of biological fluorophores. Employing 1.5 m of this fiber in a simple, all-fiber sensor setup allows us to perform multiphoton experiments without any dispersion compensation methods. Multiphoton excitation of nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD) with this fiber shows a 6- and 9-fold increase, respectively, in the total fluorescence signal collected when compared with the commercial solution in the form of a hollow-core photonic band gap fiber (HCPBF). To the author's best knowledge, this is the first time an NCHCF was used in an optical-fiber sensor setup for multiphoton fluorescence experiments.

Airflow Resistance of Loose-Fill Mineral Fiber Insulations in Retrofit Applications

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

Schumacher, C. J.; Fox, M. J.; Lstiburek, J.

2015-02-01

This report expands on Building America Report 1109 by applying the experimental apparatus and test method to dense-pack retrofit applications using mineral fiber insulation materials. Three (3) fiber glass insulation materials and one (1) stone wool insulation material were tested, and the results compared to the cellulose results from the previous study.

Carbon fiber behavior in an enclosed volume

NASA Technical Reports Server (NTRS)

Harvey, M. C.

1979-01-01

Tests were performed to evaluate the behavior of single carbon fibers existing in an enclosed space such as a room of a building. Three general phenomena were explored: the concentration decay rate of a fiber-charged room, the degree of uniform mixing of fibers within a room, and the effects of fibers being redisseminated off deposition surfaces within a room. The results were required in understanding the ratio of total indoor fiber exposure to total outdoor fiber exposure, a quantity essential to risk analysis. Results indicate that decay rate is predictable within acceptable limits and that homogeneous mixing can always be assumed. Some factors of redissemination are identified and effects discussed.

Analysis and Derivation of Allocations for Fiber Contaminants in Liquid Bipropellant Systems

NASA Technical Reports Server (NTRS)

Lowrey, N. M; ibrahim, K. Y.

2012-01-01

An analysis was performed to identify the engineering rationale for the existing particulate limits in MSFC-SPEC-164, Cleanliness of Components for Use in Oxygen, Fuel, and Pneumatic Systems, determine the applicability of this rationale to fibers, identify potential risks that may result from fiber contamination in liquid oxygen/fuel bipropellant systems, and bound each of these risks. The objective of this analysis was to determine whether fiber contamination exceeding the established quantitative limits for particulate can be tolerated in these systems and, if so, to derive and recommend quantitative allocations for fibers beyond the limits established for other particulate. Knowledge gaps were identified that limit a complete understanding of the risk of promoted ignition from an accumulation of fibers in a gaseous oxygen system.

Low-temperature hermetic sealing of optical fiber components

DOEpatents

Kramer, D.P.

1996-10-22

A method for manufacturing low-temperature hermetically sealed optical fiber components is provided. The method comprises the steps of: inserting an optical fiber into a housing, the optical fiber having a glass core, a glass cladding and a protective buffer layer disposed around the core and cladding; heating the housing to a predetermined temperature, the predetermined temperature being below a melting point for the protective buffer layer and above a melting point of a solder; placing the solder in communication with the heated housing to allow the solder to form an eutectic and thereby fill a gap between the interior of the housing and the optical fiber; and cooling the housing to allow the solder to form a hermetic compression seal between the housing and the optical fiber. 5 figs.

Coupling loss reducing for fiber Raman gas detection technology

NASA Astrophysics Data System (ADS)

Hu, Jialin; Jiang, Shubo; Zhang, Xiumei

2017-01-01

During the design of the photonic crystal fiber Raman gas detection device and taking the cost and practicability in to consideration, we choose to use a stainless steel tube as a connector for the connecting of the HCPCF and SMF to replace the fiber fusing splice. Basis on the measurement to reduce coupling loss, we calculated the optimum fiber gap for maximum light coupling and to reduce Fresnel loss. Using the stainless steel tube not only result in low loss but also benefit input of the sample gas and recycling of the fiber which is very expensive. By adjusting the central alignment of the stainless steel tube we can easily control the fiber deviation loss for specific type of SMF and HCPCF. The mode mismatch is also demonstrated.

Composition of heavy metals and airborne fibers in the indoor environment of a building during renovation.

PubMed

Latif, Mohd Talib; Baharudin, Nor Hafizah; Velayutham, Puvaneswary; Awang, Normah; Hamdan, Harimah; Mohamad, Ruqyyah; Mokhtar, Mazlin B

2011-10-01

The renovation of a building will certainly affect the quality of air in the vicinity of where associated activities were undertaken, this includes the quality of air inside the building. Indoor air pollutants such as particulate matter, heavy metals, and fine fibers are likely to be emitted during renovation work. This study was conducted to determine the concentration of heavy metals, asbestos and suspended particulates in the Biology Building, at the Universiti Kebangsaan, Malaysia (UKM). Renovation activities were carried out widely in the laboratories which were located in this building. A low-volume sampler was used to collect suspended particulate matter of a diameter size less than 10 μm (PM₁₀) and an air sampling pump, fitted with a cellulose ester membrane filter, were used for asbestos sampling. Dust was collected using a small brush and scope. The concentration of heavy metals was determined through the use of inductively coupled plasma-mass spectroscopy and the fibers were counted through a phase contrast microscope. The concentrations of PM₁₀ recorded in the building during renovation action (ranging from 166 to 542 μg m⁻³) were higher than the value set by the Department of Safety and Health for respirable dust (150 μg m⁻³). Additionally, they were higher than the value of PM₁₀ recorded in indoor environments from other studies. The composition of heavy metals in PM₁₀ and indoor dust were found to be dominated by Zn and results also showed that the concentration of heavy metals in indoor dust and PM₁₀ in this study was higher than levels recorded in other similar studies. The asbestos concentration was 0.0038 ± 0.0011 fibers/cc. This was lower than the value set by the Malaysian Department of Occupational, Safety and Health (DOSH) regulations of 0.1 fibers/cc, but higher than the background value usually recorded in indoor environments. This study strongly suggests that renovation issues need to be considered seriously by relevant stakeholders within the university in order to ensure that the associated risks toward humans and indoor environment are eliminated, or where this is not feasible, minimized as far as possible.

Asbestos exposure during renovation and demolition of asbestos-cement clad buildings

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

Brown, S.K.

External asbestos cement (AC) claddings become weathered after many years by the gradual loss of cement from exposed surfaces; as a result, loosely bound layers enriched with asbestos fibers are formed. Asbestos fibers on such weathered surfaces may be mixtures of chrysotile with amosite or crocidolite. Renovation and demolition of old AC clad buildings could cause asbestos fiber emission, but this has not been investigated in the past. The exposure of workers to asbestos dust during these operations and precautions to minimize exposure now have been investigated at several building sites. Asbestos dust concentrations during water jet cleaning or paintingmore » of weathered AC roofing were approximately 0.1 to 0.2 fibers per milliliter (f/mL). Limited results suggest that concentrations may be reduced substantially by avoiding abrasion of surfaces. Concentrations during AC roof replacement averaged approximately 0.1 f/mL and were reduced markedly by employing more careful work procedures. Asbestos dust concentrations during demolition by removal of whole sheets averaged 0.3 to 0.6 f/mL for roofs and less than 0.1 f/mL for walls, reflecting the significant differences in extent of weathering between these elements. Suppression of asbestos emissions from roof sheets by wetting or sealing of weathered surfaces was not predictable because of the occurrence of asbestos fibers in dust trapped under sheet laps.« less

A new optical post-equalization based on self-imaging

NASA Astrophysics Data System (ADS)

Guizani, S.; Cheriti, A.; Razzak, M.; Boulslimani, Y.; Hamam, H.

2005-09-01

Driven by the world's growing need for communication bandwidth, progress is constantly being reported in building newer fibers that are capable of handling the rapid increase in traffic. However, building an optical fiber link is a major investment, one that is very expensive to replace. A major impairment that restricts the achievement of higher bit rates with standard single mode fiber is chromatic dispersion. This is particularly problematic for systems operating in the 1550 nm band, where the chromatic dispersion limit decreases rapidly in inverse proportion to the square of the bit rate. For the first time, to the best of our knowledge, this document illustrates a new optical technique to post compensate optically the chromatic dispersion in fiber using temporal Talbot effect in ranges exceeding the 40G bit/s. We propose a new optical post equalization solutions based on the self imaging of Talbot effect.

Observation of stimulated emission from a single Fe-doped AlN triangular fiber at room temperature

PubMed Central

Jiang, Liangbao; Jin, Shifeng; Wang, Wenjun; Zuo, Sibin; Li, Zhilin; Wang, Shunchong; Zhu, Kaixing; Wei, Zhiyi; Chen, Xiaolong

2015-01-01

Aluminum nitride (AlN) is a well known wide-band gap semiconductor that has been widely used in fabricating various ultraviolet photo-electronic devices. Herein, we demonstrate that a fiber laser can be achieved in Fe-doped AlN fiber where Fe is the active ion and AlN fiber is used as the gain medium. Fe-doped single crystal AlN fibers with a diameter of 20–50 μm and a length of 0.5–1 mm were preparated successfully. Stimulated emission (peak at about 607 nm and FWHM ~0.2 nm) and a long luminescence lifetime (2.5 ms) were observed in the fibers by a 532nm laser excitation at room temperature. The high quality long AlN fibers are also found to be good optical waveguides. This kind of fiber lasers may possess potential advantages over traditional fiber lasers in enhancing power output and extending laser wavelengths from infrared to visible regime. PMID:26647969

To evaluate and compare the effect of different Post Surface treatments on the Tensile Bond Strength between Fiber Posts and Composite Resin.

PubMed

Shori, Deepa; Pandey, Swapnil; Kubde, Rajesh; Rathod, Yogesh; Atara, Rahul; Rathi, Shravan

2013-10-01

Fiber posts are widely used for restoration of mutilated teeth that lack adequate coronal tooth structure to retain a core for definitive restoration, bond between the fiber post and composite material depends upon the chemical reaction between the post surface and the resin material used for building up the core. In attempt to maximize the resin bonding with fiber post, different post surface conditioning is advocated. Therefore the purpose of the study is to examine the interfacial strength between fiber post and composite, as core build-up material after different surface treatments of fiber posts. Twenty fiber posts were split into four groups off five each according to different surface treatments viz. Group I-(Negative Control), Group II-Silanization (Positive control), Group III-(37% Phosphoric Acid & Silanization) ,Group IV- (10% Hydrogen Peroxide and Silanization). With the preformed plastic mould, a core of dual cure composite resin around the fiber post having the uniform thickness was created. Tensile bond strength of each specimen was measured under Universal Testing Machine (UTM) at the cross head speed of 3mm/min. The results achieved with 10% Hydrogen peroxide had a marked effect on micro tensile bond strength values between the tested materials. Immense enhancement in the silanization efficiency of quartz fiber phase was observed with different surface chemical treatment of the resin phase of fiber posts with the marked increase in the micro-tensile bond strength between fiber post and composite core. Shori D, Pandey S, Kubde R, Rathod Y, Atara R, Rathi S. To evaluate and compare the effect of different Post Surface treatments on the Tensile Bond Strength between Fiber Posts and Composite Resin. J Int Oral Health 2013; 5(5):27-32.

The ultra-structural organization of the elastic network in the intra- and inter-lamellar matrix of the intervertebral disc.

PubMed

Tavakoli, J; Elliott, D M; Costi, J J

2017-08-01

The inter-lamellar matrix (ILM)-located between adjacent lamellae of the annulus fibrosus-consists of a complex structure of elastic fibers, while elastic fibers of the intra-lamellar region are aligned predominantly parallel to the collagen fibers. The organization of elastic fibers under low magnification, in both inter- and intra-lamellar regions, was studied by light microscopic analysis of histologically prepared samples; however, little is known about their ultrastructure. An ultrastructural visualization of elastic fibers in the inter-lamellar matrix is crucial for describing their contribution to structural integrity, as well as mechanical properties of the annulus fibrosus. The aims of this study were twofold: first, to present an ultrastructural analysis of the elastic fiber network in the ILM and intra-lamellar region, including cross section (CS) and in-plane (IP) lamellae, of the AF using Scanning Electron Microscopy (SEM) and second, to -compare the elastic fiber orientation between the ILM and intra-lamellar region. Four samples (lumbar sheep discs) from adjacent sections (30μm thickness) of anterior annulus were partially digested by a developed NaOH-sonication method for visualization of elastic fibers by SEM. Elastic fiber orientation and distribution were quantified relative to the tangential to circumferential reference axis. Visualization of the ILM under high magnification revealed a dense network of elastic fibers that has not been previously described. Within the ILM, elastic fibers form a complex network, consisting of different size and shape fibers, which differed to those located in the intra-lamellar region. For both regions, the majority of fibers were oriented near 0° with respect to tangential to circumferential (TCD) direction and two minor symmetrical orientations of approximately±45°. Statistically, the orientation of elastic fibers between the ILM and intra-lamellar region was not different (p=0.171). The present study used extracellular matrix partial digestion to address significant gaps in understanding of disc microstructure and will contribute to multidisciplinary ultrastructure-function studies. Visualization of the intra-lamellar matrix under high magnification revealed a dense network of elastic fibers that has not been previously described. The present study used extracellular matrix partial digestion to address significant gaps in understanding of disc microstructure and will contribute to multidisciplinary ultrastructure-function studies. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Filling the gap: Micro-C accesses the nucleosomal fiber at 100-1000 bp resolution.

PubMed

Mozziconacci, Julien; Koszul, Romain

2015-08-21

The fine three-dimensional structure of the nucleosomal fiber has remained elusive to genome-wide chromosome conformation capture (3C) approaches. A new study mapping contacts at the single nucleosome level (Micro-C) reveals topological interacting domains along budding yeast chromosomes. These domains encompass one to five consecutive genes and are delimited by highly active promoters.

SU-F-T-424: Mitigation of Increased Surface Dose When Treating Through A Carbon Fiber Couch Top

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

Johnson, E; Misgina, F

Purpose: To study the effect of the Varian carbon fiber couch top on surface dose for patients being treated using single PA beams in the supine position and to identify simple methods for surface dose reduction. Methods: Measurements of surface dose were obtained in Solid Water phantoms using both a parallel plate ionization chamber (PTW Advanced Markus) and EBT2 Radiochromic films for both 6 and 10MV photons. All measurements were referenced to a depth considered a typical for PA Spine fields. Techniques used to reduce the surface dose included introducing an air standoff using Styrofoam sheets to suspend the phantommore » surface above the couch top and by adding a thin high Z scattering foil on the table surface. Surface doses were evaluated for typical field sizes, standoff heights, and various scattering materials. Comparisons were made to the surface dose obtainable when treating through a Varian Mylar covered tennis racket style couch top. Results: Dependence on typical spine field sizes was relatively minor. Dependence on air gap was much more significant. Surface doses decreased exponentially with increases in air standoff distance. Surface doses were reduced by approximately 50% for an air gap of 10cm and 40% for a 15cm air gap. Surface doses were reduced by an additional 15% by the addition of a 1mm Tin scattering foil. Conclusion: Using simple techniques, it is possible to reduce the surface dose when treating single PA fields through the Varian carbon fiber couch top. Surface doses can be reduced to levels observed when treating though transparent Mylar tops by adding about 15 cm of air gap. Further reductions are possible by adding thin scattering foils, such as Tin or Lead, on the couch surface. This is a low cost approach to reduce surface dose when using the Varian carbon fiber couch top.« less

Non-Neoplastic and Neoplastic Pleural Endpoints Following Fiber Exposure

PubMed Central

Broaddus, V. Courtney; Everitt, Jeffrey I.; Black, Brad; Kane, Agnes B.

2011-01-01

Exposure to asbestos fibers is associated with non-neoplastic pleural diseases including plaques, fibrosis, and benign effusions, as well as with diffuse malignant pleural mesothelioma. Translocation and retention of fibers are fundamental processes in understanding the interactions between the dose and dimensions of fibers retained at this anatomic site and the subsequent pathological reactions. The initial interaction of fibers with target cells in the pleura has been studied in cellular models in vitro and in experimental studies in vivo. The proposed biological mechanisms responsible for non-neoplastic and neoplastic pleural diseases and the physical and chemical properties of asbestos fibers relevant to these mechanisms are critically reviewed. Understanding mechanisms of asbestos fiber toxicity may help us anticipate the problems from future exposures both to asbestos and to novel fibrous materials such as nanotubes. Gaps in our understanding have been outlined as guides for future research. PMID:21534088

Innervation of taste buds revealed with Brainbow-labeling in mouse.

PubMed

Zaidi, Faisal N; Cicchini, Vanessa; Kaufman, Daniel; Ko, Elizabeth; Ko, Abraham; Van Tassel, Heather; Whitehead, Mark C

2016-12-01

Nerve fibers that surround and innervate the taste bud were visualized with inherent fluorescence using Brainbow transgenic mice that were generated by mating the founder line L with nestin-cre mice. Multicolor fluorescence revealed perigemmal fibers as branched within the non-taste epithelium and ending in clusters of multiple rounded swellings surrounding the taste pore. Brainbow-labeling also revealed the morphology and branching pattern of single intragemmal fibers. These taste bud fibers frequently innervated both the peripheral bud, where immature gemmal cells are located, and the central bud, where mature, differentiated cells are located. The fibers typically bore preterminal and terminal swellings, growth cones with filopodia, swellings, and rounded retraction bulbs. These results establish an anatomical substrate for taste nerve fibers to contact and remodel among receptor cells at all stages of their differentiation, an interpretation that was supported by staining with GAP-43, a marker for growing fibers and growth cones. © 2016 Anatomical Society.

Experimental Analysis of Steel Beams Subjected to Fire Enhanced by Brillouin Scattering-Based Fiber Optic Sensor Data

PubMed Central

Bao, Yi; Chen, Yizheng; Hoehler, Matthew S.; Smith, Christopher M.; Bundy, Matthew; Chen, Genda

2016-01-01

This paper presents high temperature measurements using a Brillouin scattering-based fiber optic sensor and the application of the measured temperatures and building code recommended material parameters into enhanced thermomechanical analysis of simply supported steel beams subjected to combined thermal and mechanical loading. The distributed temperature sensor captures detailed, nonuniform temperature distributions that are compared locally with thermocouple measurements with less than 4.7% average difference at 95% confidence level. The simulated strains and deflections are validated using measurements from a second distributed fiber optic (strain) sensor and two linear potentiometers, respectively. The results demonstrate that the temperature-dependent material properties specified in the four investigated building codes lead to strain predictions with less than 13% average error at 95% confidence level and that the Europe building code provided the best predictions. However, the implicit consideration of creep in Europe is insufficient when the beam temperature exceeds 800°C. PMID:28239230

Phononic band gap and mechanical anisotropy in spider silk

NASA Astrophysics Data System (ADS)

Papadopoulos, Periklis; Gomopoulos, Nikos; Kremer, Friedrich; Fytas, George

2010-03-01

Spider dragline silk is a semi-crystalline biopolymer exhibiting superior properties compared to synthetic polymers with similar chemical structure, such as polyamides. This is ascribed to the hierarchical nanostructure that is created in the spinning duct. During this process the aqueous solution of the two protein constituents of dragline silk is crystallized, while the macromolecules maintain their high orientation, leading to a high value of the Young's modulus (in the order of 10 GPa) along the fiber. We employed spontaneous Brillouin light scattering to measure the longitudinal modulus (M//,,M) along the two symmetry directions of the native fiber with increased (decreased) pre-strain created by stretching (supercontracting after hydration). A strong mechanical anisotropy is found; at about 18% strain M///M˜5. Most important, an unexpected finding is the first observation of a unidirectional hypersonic phononic band gap in biological structures. This relates to the existence of a strain-dependent correlation length of the mechanical modulus in the submicron range along the fiber axis.

Fiber optic sensor design for chemical process and environmental monitoring

NASA Astrophysics Data System (ADS)

Mahendran, R. S.; Harris, D.; Wang, L.; Machavaram, V. R.; Chen, R.; Kukureka, St. N.; Fernando, G. F.

2007-07-01

Cure monitoring is a term that is used to describe the cross-linking reactions in a thermosetting resin system. Advanced fiber reinforced composites are being used increasingly in a number of industrial sectors including aerospace, marine, sport, automotive and civil engineering. There is a general realization that the processing conditions that are used to manufacture the composites can have a major influence on its hot-wet mechanical properties. This paper is concerned with the design and demonstration of a number of sensor designs for in-situ cure monitoring of a model thermosetting resin system. Simple fixtures were constructed to enable a pair of cleaved optical fibers with a defined gap between the end-faces to be held in position. The resin system was introduced into this gap and the cure kinetics were followed by transmission infrared spectroscopy. A semi-empirical model was used to describe the cure process using the data obtained at different cure temperatures. The same sensor system was used to detect the ingress of moisture in the cured resin system.

Hybrid processing of laser scanning data

NASA Astrophysics Data System (ADS)

Badenko, Vladimir; Zotov, Dmitry; Fedotov, Alexander

2018-03-01

In this article the analysis of gaps in processing of raw laser scanning data and results of bridging the gaps discovered on the base of usage of laser scanning data for historic building information modeling is presented. The results of the development of a unified hybrid technology for the processing, storage, access and visualization of combined laser scanning and photography data about historical buildings are analyzed. The first result of the technology application for the historical building of St. Petersburg Polytechnic University shows reliability of the proposed approaches.

Advanced risk assessment of the effects of graphite fibers on electronic and electric equipment

NASA Technical Reports Server (NTRS)

Pocinki, L.; Cornell, M.; Kaplan, L.

1980-01-01

An assessment of the risk associated with accidents involving aircraft with carbon fiber composite structural components is examined. The individual fiber segments cause electrical and electronic equipment to fail under certain operating conditions. A Monte Carlo simulation model was used to computer the risk. Aircraft accidents with fire, release of carbon fiber material, entrainment of carbon fibers in a smoke plume transport of fibers downwind, transfer of some fibers/into the the interior of buildings, failures of electrical and electronic equipment, and economic impact of failures are discussed. Risk profiles were prepared for individual airports and the Nation. The vulnerability of electrical transmission equipment to carbon fiber incursion and aircraft accident total costs is investigated.

Fiber optical vibrometer based on a phononic crystal filter

NASA Astrophysics Data System (ADS)

Lin, Sijing; Chai, Quan; Zhang, Jianzhong

2012-02-01

We propose that phononic crystals could be used as a packaging method in a fiber optical vibrometer system to filter the vibration at unwanted frequency range. A simple FBG based vibrometer and a aluminum-silicone rubber based 1D phononic crystal with the designed phononic band gap are built up, and the corresponding experimental results are demonstrated to show the feasibility of our proposal. Our proposal also points out that optical fiber sensors could be an excellent candidate to research the inner acoustic response of more complex phononic crystals.

Preparation and measurement of FBG-based length, temperature, and vibration sensors

NASA Astrophysics Data System (ADS)

Mikel, Bretislav; Helan, Radek; Buchta, Zdenek; Jelinek, Michal; Cip, Ondrej

2016-12-01

We present system of structure health measurement by optical fiber sensors based on fiber Bragg gratings. Our system is focused to additionally install to existing buildings. We prepared first set-up of the system to monitoring of the nuclear power plant containment shape deformation. The presented system can measure up to several tens of sensors simultaneously. Each sensor contains optical fiber grating to measurement of change of length and the other independed fiber grating to monitor the temperature and the other ineligible effects.

Guidelines for Assessment and Abatement of Asbestos-Containing Materials in Buildings.

ERIC Educational Resources Information Center

Pielert, James H.; Mathey, Robert G.

This report presents guidelines, based on available information, for the assessment and abatement of asbestos-containing materials in buildings. Section 1 provides background information on the history and use of asbestos-containing products in buildings, the characteristics of asbestos fibers, products and materials containing asbestos, and…

Additive fiber-cerclages in proximal humeral fractures stabilized by locking plates

PubMed Central

Hurschler, Christof; Rech, Louise; Vosshenrich, Rolf; Lill, Helmut

2009-01-01

Background and purpose The effect of additive fiber-cerclages in proximal humeral fractures stabilized by locking plates on fracture stabilization and rotator cuff function is unclear. Here it was assessed in a human cadaver study. Methods 24 paired human shoulder specimens were harvested from median 77-year-old (range 66–85) female donors. An unstable 3-part fracture model with an intact rotator cuff was developed. 1 specimen of each pair received an additive fiber-cerclage of the rotator cuff after plate fixation, and the other one received a plate fixation without an additive fiber-cerclage. Force-controlled hydraulic cylinders were used to simulate physiological rotator cuff tension, while a robot-assisted shoulder simulator performed 4 relevant cases of load: (1) axial loading at 0°, (2) glenohumeral abduction at 60°, (3) internal rotation at 0° abduction, and (4) external rotation at 0° abduction, and imitated hanging arm weight during loading without affecting joint kinematics. A 3-dimensional real-time interfragmentary motion analysis was done in fracture gaps between the greater tuberosity and the head, as well as subcapital. The capacity of the rotator cuff to strain was analyzed with an optical system. Results Interfragmentary motion was similar between the groups with and without fiber-cerclages, in both fracture gaps and in any of the cases of load. Cerclages did not impair the capacity of the rotator cuff to strain. Interpretation Provided that unstable 3-part fractures are reduced and stabilized anatomically by a locking plate, additive fiber-cerclages do not reduce interfragmentary motion. Additive fiber-cerclages may be necessary in locking plate osteosyntheses of multiple-fractured greater tuberosities or lesser tuberosity fractures that cannot be fixed sufficiently by the plate. PMID:19562564

CODEX-aligned dietary fiber definitions help to bridge the 'fiber gap'.

PubMed

Jones, Julie Miller

2014-04-12

A comprehensive dietary fiber (DF) definition was adopted by the CODEX Alimentarius Commission (CAC) (1) to reflect the current state of knowledge about DF, (2) to recognize that all substances that behave like fiber regardless of how they are produced can be named as DF if they show physiological benefits, and (3) to promote international harmonization for food labeling and food composition tables. This review gives the history and evolution of the state of DF knowledge as looked at by refinements in DF methods and definitions subsequent to the launch of the DF hypothesis. The refinements parallel both interventional and epidemiological research leading to better understanding of the role of DF in contributing to the numerous physiological benefits imparted by all the various digestion resistant carbohydrates. A comparison of the CODEX definition (including its footnote that authorizes the inclusion of polymers with DP 3-9) and approved CODEX Type 1 methods with other existing definitions and methods will point out differences and emphasize the importance of adoption of CODEX-aligned definitions by all jurisdictions. Such harmonization enables comparison of nutrition research, recommendations, food composition tables and nutrition labels the world over. A case will be made that fibers are analogous to vitamins, in that they vary in structure, function and amount needed, but each when present in the right amount contributes to optimal health. Since the intake of DF is significantly below recommended levels throughout the world, the recognition that 'all fibers fit' is an important strategy in bridging the 'fiber gap' by enfranchising and encouraging greater intake of foods with inherent and added DF. Fortifying foods with added DF makes it easier to increase intakes while maintaining calories at recommended levels.

In vivo single branch axotomy induces GAP-43-dependent sprouting and synaptic remodeling in cerebellar cortex.

PubMed

Allegra Mascaro, Anna Letizia; Cesare, Paolo; Sacconi, Leonardo; Grasselli, Giorgio; Mandolesi, Georgia; Maco, Bohumil; Knott, Graham W; Huang, Lieven; De Paola, Vincenzo; Strata, Piergiorgio; Pavone, Francesco S

2013-06-25

Plasticity in the central nervous system in response to injury is a complex process involving axonal remodeling regulated by specific molecular pathways. Here, we dissected the role of growth-associated protein 43 (GAP-43; also known as neuromodulin and B-50) in axonal structural plasticity by using, as a model, climbing fibers. Single axonal branches were dissected by laser axotomy, avoiding collateral damage to the adjacent dendrite and the formation of a persistent glial scar. Despite the very small denervated area, the injured axons consistently reshape the connectivity with surrounding neurons. At the same time, adult climbing fibers react by sprouting new branches through the intact surroundings. Newly formed branches presented varicosities, suggesting that new axons were more than just exploratory sprouts. Correlative light and electron microscopy reveals that the sprouted branch contains large numbers of vesicles, with varicosities in the close vicinity of Purkinje dendrites. By using an RNA interference approach, we found that downregulating GAP-43 causes a significant increase in the turnover of presynaptic boutons. In addition, silencing hampers the generation of reactive sprouts. Our findings show the requirement of GAP-43 in sustaining synaptic stability and promoting the initiation of axonal regrowth.

Low-temperature hermetic sealing of optical fiber components

DOEpatents

Kramer, Daniel P.

1996-10-22

A method for manufacturing low-temperature hermetically sealed optical fi components is provided. The method comprises the steps of: inserting an optical fiber into a housing, the optical fiber having a glass core, a glass cladding and a protective buffer layer disposed around the core and cladding; heating the housing to a predetermined temperature, the predetermined temperature being below a melting point for the protective buffer layer and above a melting point of a solder; placing the solder in communication with the heated housing to allow the solder to form an eutectic and thereby fill a gap between the interior of the housing and the optical fiber; and cooling the housing to allow the solder to form a hermetic compression seal between the housing and the optical fiber.

Connexin 39.9 Protein Is Necessary for Coordinated Activation of Slow-twitch Muscle and Normal Behavior in Zebrafish*

PubMed Central

Hirata, Hiromi; Wen, Hua; Kawakami, Yu; Naganawa, Yuriko; Ogino, Kazutoyo; Yamada, Kenta; Saint-Amant, Louis; Low, Sean E.; Cui, Wilson W.; Zhou, Weibin; Sprague, Shawn M.; Asakawa, Kazuhide; Muto, Akira; Kawakami, Koichi; Kuwada, John Y.

2012-01-01

In many tissues and organs, connexin proteins assemble between neighboring cells to form gap junctions. These gap junctions facilitate direct intercellular communication between adjoining cells, allowing for the transmission of both chemical and electrical signals. In rodents, gap junctions are found in differentiating myoblasts and are important for myogenesis. Although gap junctions were once believed to be absent from differentiated skeletal muscle in mammals, recent studies in teleosts revealed that differentiated muscle does express connexins and is electrically coupled, at least at the larval stage. These findings raised questions regarding the functional significance of gap junctions in differentiated muscle. Our analysis of gap junctions in muscle began with the isolation of a zebrafish motor mutant that displayed weak coiling at day 1 of development, a behavior known to be driven by slow-twitch muscle (slow muscle). We identified a missense mutation in the gene encoding Connexin 39.9. In situ hybridization found connexin 39.9 to be expressed by slow muscle. Paired muscle recordings uncovered that wild-type slow muscles are electrically coupled, whereas mutant slow muscles are not. The further examination of cellular activity revealed aberrant, arrhythmic touch-evoked Ca2+ transients in mutant slow muscle and a reduction in the number of muscle fibers contracting in response to touch in mutants. These results indicate that Connexin 39.9 facilitates the spreading of neuronal inputs, which is irregular during motor development, beyond the muscle cells and that gap junctions play an essential role in the efficient recruitment of slow muscle fibers. PMID:22075003

Buildings of the Future Scoping Study: A Framework for Vision Development

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

Wang, Na; Goins, John D.

2015-02-01

The Buildings of the Future Scoping Study, funded by the U.S. Department of Energy (DOE) Building Technologies Office, seeks to develop a vision for what U.S. mainstream commercial and residential buildings could become in 100 years. This effort is not intended to predict the future or develop a specific building design solution. Rather, it will explore future building attributes and offer possible pathways of future development. Whether we achieve a more sustainable built environment depends not just on technologies themselves, but on how effectively we envision the future and integrate these technologies in a balanced way that generates economic, social,more » and environmental value. A clear, compelling vision of future buildings will attract the right strategies, inspire innovation, and motivate action. This project will create a cross-disciplinary forum of thought leaders to share their views. The collective views will be integrated into a future building vision and published in September 2015. This report presents a research framework for the vision development effort based on a literature survey and gap analysis. This document has four objectives. First, it defines the project scope. Next, it identifies gaps in the existing visions and goals for buildings and discusses the possible reasons why some visions did not work out as hoped. Third, it proposes a framework to address those gaps in the vision development. Finally, it presents a plan for a series of panel discussions and interviews to explore a vision that mitigates problems with past building paradigms while addressing key areas that will affect buildings going forward.« less

Shared resources : sharing right-of-way for telecommunications : identificaiton, review and analysis of legal and institutional issues

DOT National Transportation Integrated Search

1996-04-01

The advent of fiber-optic communications technology coupled with continued rapid growth in demand for communications capacity have led private communications companies to seek to build new, and extend existing, fiber-optics networks. There is increas...

77 FR 76435 - Connect America Fund

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-28

... excluding Phase I fiber from Phase II support is that the Bureau would not likely receive information... carriers should be restricted in building fiber, what information carriers should be required to provide... additional information on the rulemaking process, see the SUPPLEMENTARY INFORMATION section of this document...

The Master Clock Building at USNO Infrastructure

DTIC Science & Technology

2008-12-01

type finish on top of about 3.5 inches of foam insulation. This along with cinder block, fiber glass insulation, and 5/8-inch-X drywall provides a...keep the building on temperature. The outside surface of the building is an “Exterior Finish Insulation Systems” (EFIS). This is made up of a stucco

Fiber-handling robot and optical connection mechanisms for automatic cross-connection of multiple optical connectors

NASA Astrophysics Data System (ADS)

Mizukami, Masato; Makihara, Mitsuhiro

2013-07-01

Conventionally, in intelligent buildings in a metropolitan area network and in small-scale facilities in the optical access network, optical connectors are joined manually using an optical connection board and a patch panel. In this manual connection approach, mistakes occur due to discrepancies between the actual physical settings of the connections and their management because these processes are independent. Moreover, manual cross-connection is time-consuming and expensive because maintenance personnel must be dispatched to remote places to correct mistakes. We have developed a fiber-handling robot and optical connection mechanisms for automatic cross-connection of multiple optical connectors, which are the key elements of automatic optical fiber cross-connect equipment. We evaluate the performance of the equipment, such as its optical characteristics and environmental specifications. We also devise new optical connection mechanisms that enable the automated optical fiber cross-connect module to handle and connect angled physical contact (APC) optical connector plugs. We evaluate the performance of the equipment, such as its optical characteristics. The evaluation results confirm that the automated optical fiber cross-connect equipment can connect APC connectors with low loss and high return loss, indicating that the automated optical fiber cross-connect equipment is suitable for practical use in intelligent buildings and optical access networks.

Textile electrodes woven by carbon nanotube-graphene hybrid fibers for flexible electrochemical capacitors.

PubMed

Cheng, Huhu; Dong, Zelin; Hu, Chuangang; Zhao, Yang; Hu, Yue; Qu, Liangti; Chen, Nan; Dai, Liming

2013-04-21

Functional graphene-based fibers are promising as new types of flexible building blocks for the construction of wearable architectures and devices. Unique one-dimensional (1D) carbon nanotubes (CNTs) and 2D graphene (CNT/G) hybrid fibers with a large surface area and high electrical conductivity have been achieved by pre-intercalating graphene fibers with Fe3O4 nanoparticles for subsequent CVD growth of CNTs. The CNT/G hybrid fibers can be further woven into textile electrodes for the construction of flexible supercapacitors with a high tolerance to the repeated bending cycles. Various other applications, such as catalysis, separation, and adsorption, can be envisioned for the CNT/G hybrid fibers.

Surveys for sensitivity to fibers and potential impacts from fiber induced failures

NASA Technical Reports Server (NTRS)

Butterfield, A. J.

1979-01-01

The surveys for sensitivities to fibers and potential impacts from fiber induced failures begins with a review of the survey work completed to date and then describes an impact study involving four industrial installations located in Virginia. The observations and results from both the surveys and the study provide guidelines for future efforts. The survey work was done with three broad objectives: (1) identify the pieces of potentially vulnerable equipment as candidates for test; (2) support the transfer function work by gaining an understanding of how fibers could get into a building; and (3) support the economic analysis by understanding what would happen if fibers precipitated a failure in an item of equipment.

Analysis of second order harmonic distortion due to transmitter non-linearity and chromatic and modal dispersion of optical OFDM SSB modulated signals in SMF-MMF fiber links

NASA Astrophysics Data System (ADS)

Patel, Dhananjay; Singh, Vinay Kumar; Dalal, U. D.

2017-01-01

Single mode fibers (SMF) are typically used in Wide Area Networks (WAN), Metropolitan Area Networks (MAN) and also find applications in Radio over Fiber (RoF) architectures supporting data transmission in Fiber to the Home (FTTH), Remote Antenna Units (RAUs), in-building networks etc. Multi-mode fibers (MMFs) with low cost, ease of installation and low maintenance are predominantly (85-90%) deployed in-building networks providing data access in local area networks (LANs). The transmission of millimeter wave signals through the SMF in WAN and MAN, along with the reuse of MMF in-building networks will not levy fiber reinstallation cost. The transmission of the millimeter waves experiences signal impairments due to the transmitter non-linearity and modal dispersion of the MMF. The MMF exhibiting large modal dispersion limits the bandwidth-length product of the fiber. The second and higher-order harmonics present in the optical signal fall within the system bandwidth. This causes degradation in the received signal and an unwanted radiation of power at the RAU. The power of these harmonics is proportional to the non-linearity of the transmitter and the modal dispersion of the MMF and should be maintained below the standard values as per the international norms. In this paper, a mathematical model is developed for Second-order Harmonic Distortion (HD2) generated due to non-linearity of the transmitter and chromatic-modal dispersion of the SMF-MMF optic link. This is also verified using a software simulation. The model consists of a Mach Zehnder Modulator (MZM) that generates two m-QAM OFDM Single Sideband (SSB) signals based on phase shift of the hybrid coupler (90° and 120°). Our results show that the SSB signal with 120° hybrid coupler has suppresses the higher-order harmonics and makes the system more robust against the HD2 in the SMF-MMF optic link.

E-to-E: Spanning Opportunity and Skills Gaps with Education-to-Employment Pathways

ERIC Educational Resources Information Center

Gittell, Ross; Hitchcock, Jeremy

2016-01-01

This article reports on a skills gap problem experienced in New England states where the economy has improved, but economic opportunity and skills gaps contribute to slower growth in employment, income, and social mobility. The article suggests ways to overcome this gap by building stronger bridges between education and employment…

Adaptation of adhesive post and cores to dentin after in vitro occlusal loading: evaluation of post material influence.

PubMed

Dietschi, Dider; Ardu, Stefano; Rossier-Gerber, Anne; Krejci, Ivo

2006-12-01

Fatigue resistance of post and cores is critical to the long term behavior of restored nonvital teeth. The purpose of this in vitro trial was to evaluate the influence of the post material's physical properties on the adaptation of adhesive post and core restorations after cyclic mechanical loading. Composite post and cores were made on endodontically treated deciduous bovine teeth using 3 anisotropic posts (made of carbon, quartz, or quartz-and-carbon fibers) and 3 isotropic posts (zirconium, stainless steel, titanium). Specimens were submitted to 3 successive loading phases--250,000 cycles at 50 N, 250,000 at 75 N, and 500,000 at 100 N--at a rate of 1.5 Hz. Restoration adaptation was evaluated under SEM, before and during loading (margins) and after test completion (margins and internal interfaces). Six additional samples were fabricated for the characterization of interface micromorphology using confocal microscopy. Mechanical loading increased the proportion of marginal gaps in all groups; carbon fiber posts presented the lowest final gap proportion (7.11%) compared to other stiffer metal-ceramic or softer fiber posts (11.0% to 19.1%). For internal adaptation, proportions of debonding between dentin and core or cement varied from 21.69% (carbon post) to 47.37% (stainless steel post). Debonding at the post-cement interface occurred only with isotropic materials. Confocal microscopy observation revealed that gaps were generally associated with an incomplete hybrid layer and reduced resin tags. Regardless of their rigidity, metal and ceramic isotropic posts proved less effective than fiber posts at stabilizing the post and core structure in the absence of the ferrule effect, due to the development of more interfacial defects with either composite or dentin.

Promotion of lens epithelial-fiber differentiation by the C-terminus of connexin 45.6 a role independent of gap junction communication.

PubMed

Banks, Eric A; Yu, X Sean; Shi, Qian; Jiang, Jean X

2007-10-15

We previously reported that, among the three connexins expressed in chick lens, overexpression of connexin (Cx) 45.6, not Cx43 or Cx56, stimulates lens cell differentiation; however, the underlying mechanism responsible for this effect is unclear. Here, we took advantage of naturally occurring loss-of-gap-junction function mutations of Cx50 (ortholog of chick Cx45.6) and generated the corresponding site mutants in Cx45.6: Cx45.6(D47A) and Cx45.6(P88S). In contrast to wild-type Cx45.6, the mutants failed to form functional gap junctions, and Cx45.6(P88S) and, to a lesser degree, Cx45.6(D47A) functioned in a dominant-negative manner. Interestingly, overexpression of both mutants incapable of forming gap junctions significantly increased epithelial-fiber differentiation to a level comparable to that of wild-type Cx45.6. To map the functional domain of Cx45.6, we generated a C-terminus chimera as well as deletion mutants. Overexpression of Cx56(*)45.6C, the mutant in which the C-terminus of Cx56 was replaced with that of Cx45.6, had a stimulatory effect on lens cell differentiation similar to that of Cx45.6. However, cells overexpressing Cx45.6(*)56C, the mutant in which C-terminus of Cx45.6 was replaced with that of Cx56, and Cx45.6(-C), in which the C-terminus was deleted, failed to promote differentiation. Taken together, we conclude that the expression of Cx45.6, but not Cx45.6-dependent gap junction channels, is involved in lens epithelial-fiber cell differentiation, and the C-terminal domain of Cx45.6 plays a predominant role in mediating this process.

Fiber-Optic Distribution Of Pulsed Power To Multiple Sensors

NASA Technical Reports Server (NTRS)

Kirkham, Harold

1996-01-01

Optoelectronic systems designed according to time-sharing scheme distribute optical power to multiple integrated-circuit-based sensors in fiber-optic networks. Networks combine flexibility of electronic sensing circuits with advantage of electrical isolation afforded by use of optical fibers instead of electrical conductors to transmit both signals and power. Fiber optics resist corrosion and immune to electromagnetic interference. Sensor networks of this type useful in variety of applications; for example, in monitoring strains in aircraft, buildings, and bridges, and in monitoring and controlling shapes of flexible structures.

EVALUATION OF AEROSOLIZATION OF ASBESTOS AND RELATED FIBERS FROM BULK MATERIALS

EPA Science Inventory

1. Status Report on the Evaluation of the Alternative Asbestos Control Method – A Comparison to the NESHAP Method of Demolition of Asbestos Containing Buildings; and, 2. Update on the Evaluation of Aerosolization of Asbestos and Related Fibers from Bulk Materials. This abstract a...

Studies on the inhalation toxicology of two fiberglasses and amosite asbestos in the Syrian golden hamster. Part II. Results of chronic exposure.

PubMed

McConnell, E E; Axten, C; Hesterberg, T W; Chevalier, J; Miiller, W C; Everitt, J; Oberdörster, G; Chase, G R; Thevenaz, P; Kotin, P

1999-09-01

Fiberglass (FG) is the largest category of man-made mineral fibers (MMVFs). Many types of FG are manufactured for specific uses building insulation, air handling, filtration, and sound absorption. In the United States, > 95% of FG produced is for building insulation. Several inhalation studies in rodents of FG building insulation have shown no indication of pulmonary fibrosis or carcinogenic activity. However, because of increasing use and potential for widespread human exposure, a chronic toxicity/carcinogenicity inhalation study of a typical building insulation FG (MMVF 10a) was conducted in hamsters, which were shown to be highly sensitive to the induction of mesotheliomas with another MMVF. A special-application FG (MMVF 33) and amosite asbestos were used for comparative purposes. Groups of 140 weanling male Syrian golden hamsters were exposed via nose-only inhalation for 6 h/day, 5 days/wk for 78 wk to either filtered air (chamber controls) or MMVF 10a, MMVF 33, or amosite asbestos at 250-300 WHO fibers/cm(3) with two additional amosite asbestos groups at 25 and 125 WHO fibers/cm(3). They were then held unexposed for 6 wk until approximately 10-20% survival. After 13, 26, 52, and 78 wk, various pulmonary parameters and lung fiber burdens were evaluated. Groups hamsters were removed from exposure at 13 and 52 wk and were held until 78 wk (recovery groups). Initial lung deposition of long fibers (>20 microm in length) after a single 6-h exposure was similar for all 3 fibers exposed to 250-300 fibers/cm(3). MMVF 10a lungs showed inflammation (which regressed in recovery hamsters) but no pulmonary or pleural fibrosis or neoplasms. MMVF 33 induced more severe inflammation and mild interstitial and pleural fibrosis by 26 wk that progressed in severity until 52 wk, after which it plateaued. While the inflammatory lesions regressed in the recovery animals, pulmonary or pleural fibrosis did not. A single multicentric mesothelioma was observed at 32 wk. No neoplasms were found in the remainder of the study. Amosite asbestos produced dose-related inflammation and pulmonary and pleural fibrosis as early as 13 wk in all 3 exposure levels. The lesions progressed during the course of the study, and at 78 wk severe pulmonary fibrosis with large areas of consolidation was observed in the highest 2 exposure groups. Progressive pleural fibrosis with mesothelial hypertrophy and hyperplasia was present in the thoracic wall and diaphragm in most animals and increased with time in the recovery hamsters. While no pulmonary neoplasms were observed in the amosite exposed hamsters, a large number of mesotheliomas were found; 25 fibers/cm(3), 3.6%; 125 fibers/cm(3), 25.9%; and 250 fibers/cm(3), 19.5%. For the 3 fiber types, the severity of the lung and pleural lesions generally paralleled the cumulative fiber burden, especially those >20 microm length, in the lung, thoracic wall, and diaphragm. They also inversely paralleled the in vitro dissolution rates; that is, the faster the dissolution, the lower were the cumulative lung burdens and the less severe the effects.

Health monitoring system for a tall building with Fiber Bragg grating sensors

NASA Astrophysics Data System (ADS)

Li, D. S.; Li, H. N.; Ren, L.; Guo, D. S.; Song, G. B.

2009-03-01

Fiber Bragg grating (FBG) sensors demonstrate great potentials for structural health monitoring of civil structures to ensure their structural integrity, durability and reliability. The advantages of applying fiber optic sensors to a tall building include their immunity of electromagnetic interference and multiplexing ability to transfer optical signals over a long distance. In the work, FBG sensors, including strain and temperature sensors, are applied to the construction monitoring of an 18-floor tall building starting from its construction date. The main purposes of the project are: 1) monitoring the temperature evolution history within the concrete during the pouring process; 2) measuring the variations of the main column strains on the underground floor while upper 18 floors were subsequently added on; and 3) monitoring the relative displacements between two foundation blocks. The FBG sensors have been installed and interrogated continuously for more than five months. Monitoring results of temperature and strains during the period are presented in the paper. Furthermore, the lag behavior between the concrete temperature and its surrounding air temperature is investigated.

Scintillating fiber-based photon beam profiler for the Jefferson Lab tagged photon beam line

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

Zorn, C.; Barbosa, F.J.; Freyberger, A.

2000-10-01

A scintillating fiber hodoscope has been built for use as a photon beam profiler in the bremsstrahlung tagged photon beam in Hall B of the Thomas Jefferson National Accelerator Facility (Jefferson Lab). The device consists of a linear array of 64 2-2 mm2 scintillating fibers glued to a corresponding set of light guide fibers. Both fiber types use double-clad technology for maximum intensity. The light guide fibers are gently bent into a square array of holes and air-gap coupled to four compact position-sensitive photomultipliers (16 channel Hamamatsu R5900-M16). Custom electronics amplifies and converts the analog outputs to ECL pulses whichmore » are counted by VME-based scalars. The device consisting of the fibers, photomultipliers, and electronics is sealed within a light-tight aluminum box. Two modules make up a beam imaging 2-D system. The system has been tested successfully during an experimental run« less

Strength Analysis of Coconut Fiber Stabilized Earth for Farm Structures

NASA Astrophysics Data System (ADS)

Enokela, O. S.; P. O, Alada

2012-07-01

Investigation of the strength characteristic of soil from alluvial deposit of River Benue in makurdi stabilized with coconut fiber as a stabilizer was carried as local building material for farm structure. Processed coconut fibers were mixed with the soil at four different mix ratios of 1% fiber, 2% fiber, 3% fiber and 4% fiber by percentage weight with 0% fiber as control. Compaction test and compressive strength were carried out on the various stabilizing ratio. From the compaction test, the correlation between the maximum dry density and optimum moisture content is a second order polynomial with a coefficient of 63% obtained at1.91kg/m3and 20.0% respectively while the compressive strength test shows an optimum failure load of 8.62N/mm2 at 2%fibre:100% soil mix ratio at 2.16 maximum dry density.

Durability of pulp fiber-cement composites

NASA Astrophysics Data System (ADS)

Mohr, Benjamin J.

Wood pulp fibers are a unique reinforcing material as they are non-hazardous, renewable, and readily available at relatively low cost compared to other commercially available fibers. Today, pulp fiber-cement composites can be found in products such as extruded non-pressure pipes and non-structural building materials, mainly thin-sheet products. Although natural fibers have been used historically to reinforce various building materials, little scientific effort has been devoted to the examination of natural fibers to reinforce engineering materials until recently. The need for this type of fundamental research has been emphasized by widespread awareness of moisture-related failures of some engineered materials; these failures have led to the filing of national- and state-level class action lawsuits against several manufacturers. Thus, if pulp fiber-cement composites are to be used for exterior structural applications, the effects of cyclical wet/dry (rain/heat) exposure on performance must be known. Pulp fiber-cement composites have been tested in flexure to examine the progression of strength and toughness degradation. Based on scanning electron microscopy (SEM), environmental scanning electron microscopy (ESEM), energy dispersive spectroscopy (EDS), a three-part model describing the mechanisms of progressive degradation has been proposed: (1) initial fiber-cement/fiber interlayer debonding, (2) reprecipitation of crystalline and amorphous ettringite within the void space at the former fiber-cement interface, and (3) fiber embrittlement due to reprecipitation of calcium hydroxide filling the spaces within the fiber cell wall structure. Finally, as a means to mitigate kraft pulp fiber-cement composite degradation, the effects of partial portland cement replacement with various supplementary cementitious materials (SCMs) has been investigated for their effect on mitigating kraft pulp fiber-cement composite mechanical property degradation (i.e., strength and toughness losses) during wet/dry cycling. SCMs have been found to be effective in mitigating composite degradation through several processes, including a reduction in the calcium hydroxide content, stabilization of monosulfate by maintaining pore solution pH, and a decrease in ettringite reprecipitation accomplished by increased binding of aluminum in calcium aluminate phases and calcium in the calcium silicate hydrate (C-S-H) phase.

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

Kochhar, G.S.; Manohar, K.

Cost is one of the major factors to be considered when choosing a thermal insulator. Design engineers continuously strive to provide the best at the lowest possible cost. In the tropics climate conditions are essentially hot and humid and a cause for daily discomfort. To some extent, air-conditioning of buildings has solved this problem. The major deterrent to air-conditioning is the exorbitant cost of imported thermal insulation materials. This has prompted a search for local, low-cost but effective thermal insulation for buildings. Coconut fiber is available at minimal cost from the copra industry in Trinidad, as it is a wastemore » product from the coconut. The viability of using coconut fiber as building thermal insulation was explored by conducting thermal conductivity tests on 200 mm X 400 mm X 60 mm thick slab-like specimens. The test equipment used was a locally designed constant temperature hot box apparatus. This apparatus was designed to test slab-like specimens under steady-state conditions. The reliability if this experimental set up was checked using Gypsum Plaster. The thermal conductivity test results for coconut fiber over the density range 30 kg/m{sup 3} to 115 kg/m{sup 3} showed the characteristic hooked shape graph for fibrous material. For the 60 mm thick specimens at a mean temperature of 39 C, a minimum thermal conductivity of 0.058 W/mK occurred at an optimum density of 85 kg/m{sup 3}. The thermal conductivity of commonly used industrial insulators, namely loose-fill expanded vermiculite, cellular glass and blanket fiber glass, at a mean temperature of 38 C are 0.066 W/mK, 0.061 W/mK and 0.052 W/mK respectively. When compared, these results show that air dried coconut fiber has far reaching potential for use as an effective building thermal insulation.« less

Optical fiber curvature sensor based on MMF-SCF-MMF structure

NASA Astrophysics Data System (ADS)

Wang, Qi; Liu, Yu

2018-07-01

A sensitive curvature sensor based on MMF-SCF-MMF (MMF: multimode fiber; SCF: seven core fiber) structure is proposed. The multimode fiber (MMF) are used to improve the light coupling efficiency between the input singlemode fiber (SMF) and the seven-core fiber (SCF), and the seven-core fiber is used as the main element for curvature measurement. Experimental results show that the best curvature sensitivity reaches 41.46453 nm/m-1 in the range of 0.094 m-1-0.567 m-1. The temperature sensitivity is up to 59.02 pm/°C in the range of 20 °C-55 °C. The optical curvature sensors are widely used for buildings structure health monitoring and mechanical engineering due to the advantages of compact structure, anti-electromagnetic interference, and low cost.

A miniature extrinsic fiber Fabry-Perot pressure sensor based on fiber etching

NASA Astrophysics Data System (ADS)

Ge, Yixian; Wang, Ming; Yang, Chundi

2009-10-01

This paper presents a miniature fiber optic pressure sensor based on Fabry-Perot interference fabricated on the tip of a single mode (SM) fiber. The sensor measures only 125μm in diameter. A Fabry-Perot cavity and a thin silica diaphragm are fabricated by simple techniques involving only fusion splicing, cleaving, and wet chemical etching. Interference pattern of the sensor is analyzed and issues in sensor design are discussed. The overall chemical reaction of the fiber wet etching is specifically represented. Pressure testing system is carried out. By tracing a peak point in the interference spectrum, the gap length of the sensor can be demodulated. The sensor is made entirely of fused silica, whose structure has good stability, cabinet, simple for fabrication and low cost. It may also find uses in medical applications.

A miniature extrinsic fiber Fabry-Perot pressure sensor based on fiber etching

NASA Astrophysics Data System (ADS)

Ge, Yixian; Zhou, Junping; Wang, Tingting

2011-11-01

A miniature fiber optic pressure sensor based on Fabry-Perot interference fabricated on the tip of a single mode (SM) fiber is presented. The sensor measures only 125μm in diameter. A Fabry-Perot cavity and a thin silica diaphragm are fabricated by simple techniques involving only cleaving, wet chemical etching and fusion splicing. Interference pattern of the sensor is analyzed and issues in sensor design are discussed. The overall chemical reaction of the fiber wet etching is specifically represented. Pressure testing system is carried out. By tracing a peak point in the interference spectrum, the gap length of the sensor can be demodulated. Experimental results show the sensor has a good linearity. The sensor is made entirely of fused silica, whose structure has good stability, cabinet, simple for fabrication and low cost.

Two-Photon Excited Fluorescence from Biological Aerosol Particles

DTIC Science & Technology

2010-09-29

in material damage. We overcame these limitations by building a band-limited Yb-doped fiber laser with no dispersion compensation [9], as the master...master oscillator was an all-normal- dispersion Yb-doped fiber laser [9], followed by high- dispersion fiber for stretching the pulses, a single-mode...of ~670 fs in duration, and its expected transform-limited pulse width for a normal- dispersion laser with this spectral width would be ~454 fs [10

I90/94 fiber backbone network and spurs build-out. Phase II

DOT National Transportation Integrated Search

2006-09-05

The Wisconsin Department of Transportation (WisDOT) received 36 strands of dark fiber located on I-94 right of way, running the entire length of the corridor in Wisconsin. This was the result of a right of way exchange WisDOT executed in 2000. Althou...

Fiber-optic sensor design for chemical process and environmental monitoring

NASA Astrophysics Data System (ADS)

Mahendran, R. S.; Wang, L.; Machavaram, V. R.; Pandita, S. D.; Chen, R.; Kukureka, S. N.; Fernando, G. F.

2009-10-01

"Curing" is a term that is used to describe the cross-linking reactions in a thermosetting resin system. Advanced fiber-reinforced composites are being used increasingly in a number of industrial sectors including aerospace, marine, sport, automotive and civil engineering. There is a general realization that the processing conditions that are used to manufacture the composite can have a major influence on its hot-wet mechanical properties. This paper is concerned with the design and demonstration of a number of sensor designs for in situ monitoring of the cross-linking reactions of a commercially available thermosetting resin system. Simple fixtures were constructed to enable a pair of cleaved optical fibers with a defined gap between the end-faces to be held in position. The resin system was introduced into this gap and the cure kinetics were followed by transmission infrared spectroscopy. A semi-empirical model was used to describe the cure process using the data obtained at different cure temperatures. The same sensor system was used to detect the ingress of moisture into the cured resin system.

Electrically tunable zero dispersion wavelengths in photonic crystal fibers filled with a dual frequency addressable liquid crystal

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

Wahle, Markus, E-mail: markus.wahle@uni-paderborn.de; Kitzerow, Heinz-Siegfried

2015-11-16

We present a liquid crystal (LC) infiltrated photonic crystal fiber, which enables the electrical tuning of the position of zero dispersion wavelengths (ZDWs). A dual frequency addressable liquid crystal is aligned perpendicular on the inclusion walls of a photonic crystal fiber, which results in an escaped radial director field. The orientation of the LC is controlled by applying an external electric field. Due to the high index of the liquid crystal the fiber guides light by the photonic band gap effect. Multiple ZDWs exist in the visible and near infrared. The positions of the ZDWs can be either blue ormore » red shifted depending on the frequency of the applied voltage.« less

OVERVIEW ON ALTERNATIVE ASBESTOS CONTROL METHOD RESEARCH

EPA Science Inventory

The alternative asbestos control method (AACM) is an experimental approach to building demolition. Unlike the NESHAP method, the AACM allows some regulated asbestos-containing material to remain in the building and a surfactant-water solution is used to suppress asbestos fibers ...

A continuous process to align electrospun nanofibers into parallel and crossed arrays

NASA Astrophysics Data System (ADS)

Laudenslager, Michael J.; Sigmund, Wolfgang M.

2013-04-01

Electrical, optical, and mechanical properties of nanofibers are strongly affected by their orientation. Electrospinning is a nanofiber processing technique that typically produces nonwoven meshes of randomly oriented fibers. While several alignment techniques exist, they are only able to produce either a very thin layer of aligned fibers or larger quantities of fibers with less control over their alignment and orientation. The technique presented herein fills the gap between these two methods allowing one to produce thick meshes of highly oriented nanofibers. In addition, this technique is not limited to collection of fibers along a single axis. Modifications to the basic setup allow collection of crossed fibers without stopping and repositioning the apparatus. The technique works for a range of fiber sizes. In this study, fiber diameters ranged from 100 nm to 1 micron. This allows a few fibers at a time to rapidly deposit in alternating directions creating an almost woven structure. These aligned nanofibers have the potential to improve the performance of energy storage and thermoelectric devices and hold great promise for directed cell growth applications.

Thermal degradation study of silicon carbide threads developed for advanced flexible thermal protection systems

NASA Technical Reports Server (NTRS)

Tran, Huy Kim; Sawko, Paul M.

1992-01-01

Silicon carbide (SiC) fiber is a material that may be used in advanced thermal protection systems (TPS) for future aerospace vehicles. SiC fiber's mechanical properties depend greatly on the presence or absence of sizing and its microstructure. In this research, silicon dioxide is found to be present on the surface of the fiber. Electron Spectroscopy for Chemical Analysis (ESCA) and Scanning Electron Microscopy (SEM) show that a thin oxide layer (SiO2) exists on the as-received fibers, and the oxide thickness increases when the fibers are exposed to high temperature. ESCA also reveals no evidence of Si-C bonding on the fiber surface on both as-received and heat treated fibers. The silicon oxide layer is thought to signal the decomposition of SiC bonds and may be partially responsible for the degradation in the breaking strength observed at temperatures above 400 C. The variation in electrical resistivity of the fibers with increasing temperature indicates a transition to a higher band gap material at 350 to 600 C. This is consistent with a decomposition of SiC involving silicon oxide formation.

Life cycle assessment of hemp cultivation and use of hemp-based thermal insulator materials in buildings.

PubMed

Zampori, Luca; Dotelli, Giovanni; Vernelli, Valeria

2013-07-02

The aim of this research is to assess the sustainability of a natural fiber, such as hemp (Cannabis sativa), and its use as thermal insulator for building applications. The sustainability of hemp was quantified by life cycle assessment (LCA) and particular attention was given to the amount of CO2eq of the whole process, and the indicator greenhouse gas protocol (GGP) was selected to quantify CO2eq emissions. In this study also CO2 uptake of hemp was considered. Two different allocation procedures (i.e., mass and economic) were adopted. Other indicators, such as Cumulative Energy Demand (CED) and EcoIndicator99 H were calculated. The production of 1 ha yielded 15 ton of hemp, whose global warming potential (GWP100) was equal to about -26.01 ton CO2eq: the amount allocated to the technical fiber (20% of the total amount of hemp biomass) was -5.52 ton CO2eq when mass allocation was used, and -5.54 ton CO2eq when economic allocation was applied. The sustainability for building applications was quantified by considering an insulation panel made by hemp fiber (85%) and polyester fiber (15%) in 1 m(2) of wall having a thermal transmittance (U) equal to 0.2 W/m(2)_K. The environmental performances of the hemp-based panel were compared to those of a rockwool-based one.

Connexin36 Expression in Primary Afferent Neurons in Relation to the Axon Reflex and Modality Coding of Somatic Sensation.

PubMed

Nagy, J I; Lynn, B D; Senecal, J M M; Stecina, K

2018-05-07

Electrical coupling mediated by connexin36-containing gap junctions that form electrical synapses is known to be prevalent in the central nervous system, but such coupling was long ago reported also to occur between cutaneous sensory fibers. Here, we provide evidence supporting the capability of primary afferent fibers to engage in electrical coupling. In transgenic mice with enhanced green fluorescent protein (eGFP) serving as a reporter for connexin36 expression, immunofluorescence labeling of eGFP was found in subpopulations of neurons in lumbar dorsal root and trigeminal sensory ganglia, and in fibers within peripheral nerves and tissues. Immunolabeling of connexin36 was robust in the sciatic nerve, weaker in sensory ganglia than in peripheral nerve, and absent in these tissues from Cx36 null mice. Connexin36 mRNA was detected in ganglia from wild-type mice, but not in those from Cx36 null mice. Labeling of eGFP was localized within a subpopulation of ganglion cells containing substance P and calcitonin gene-releasing peptide, and in peripheral fibers containing these peptides. Expression of eGFP was also found in various proportions of sensory ganglion neurons containing transient receptor potential (TRP) channels, including TRPV1 and TRPM8. Ganglion cells labeled for isolectin B4 and tyrosine hydroxylase displayed very little co-localization with eGFP. Our results suggest that previously observed electrical coupling between peripheral sensory fibers occurs via electrical synapses formed by Cx36-containing gap junctions, and that some degree of selectivity in the extent of electrical coupling may occur between fibers belonging to subpopulations of sensory neurons identified according to their sensory modality responsiveness. Copyright © 2018 IBRO. Published by Elsevier Ltd. All rights reserved.

Lens intracellular hydrostatic pressure is generated by the circulation of sodium and modulated by gap junction coupling

PubMed Central

Gao, Junyuan; Sun, Xiurong; Moore, Leon C.; White, Thomas W.; Brink, Peter R.

2011-01-01

We recently modeled fluid flow through gap junction channels coupling the pigmented and nonpigmented layers of the ciliary body. The model suggested the channels could transport the secretion of aqueous humor, but flow would be driven by hydrostatic pressure rather than osmosis. The pressure required to drive fluid through a single layer of gap junctions might be just a few mmHg and difficult to measure. In the lens, however, there is a circulation of Na+ that may be coupled to intracellular fluid flow. Based on this hypothesis, the fluid would cross hundreds of layers of gap junctions, and this might require a large hydrostatic gradient. Therefore, we measured hydrostatic pressure as a function of distance from the center of the lens using an intracellular microelectrode-based pressure-sensing system. In wild-type mouse lenses, intracellular pressure varied from ∼330 mmHg at the center to zero at the surface. We have several knockout/knock-in mouse models with differing levels of expression of gap junction channels coupling lens fiber cells. Intracellular hydrostatic pressure in lenses from these mouse models varied inversely with the number of channels. When the lens’ circulation of Na+ was either blocked or reduced, intracellular hydrostatic pressure in central fiber cells was either eliminated or reduced proportionally. These data are consistent with our hypotheses: fluid circulates through the lens; the intracellular leg of fluid circulation is through gap junction channels and is driven by hydrostatic pressure; and the fluid flow is generated by membrane transport of sodium. PMID:21624945

Electron tomographic analysis of gap junctions in lateral giant fibers of crayfish.

PubMed

Ohta, Yasumi; Nishikawa, Kouki; Hiroaki, Yoko; Fujiyoshi, Yoshinori

2011-07-01

Innexin-gap junctions in crayfish lateral giant fibers (LGFs) have an important role in escape behavior as a key component of rapid signal transduction. Knowledge of the structure and function of characteristic vesicles on the both sides of the gap junction, however, is limited. We used electron tomography to analyze the three-dimensional structure of crayfish gap junctions and gap junctional vesicles (GJVs). Tomographic analyses showed that some vesicles were anchored to innexons and almost all vesicles were connected by thin filaments. High densities inside the GJVs and projecting densities on the GJV membranes were observed in fixed and stained samples. Because the densities inside synaptic vesicles were dependent on the fixative conditions, different fixative conditions were used to elucidate the molecules included in the GJVs. The projecting densities on the GJVs were studied by immunoelectron microscopy with anti-vesicular monoamine transporter (anti-VMAT) and anti-vesicular nucleotide transporter (anti-VNUT) antibodies. Some of the projecting densities were labeled by anti-VNUT, but not anti-VMAT. Three-dimensional analyses of GJVs and excitatory chemical synaptic vesicles (CSVs) revealed clear differences in their sizes and central densities. Furthermore, the imaging data obtained under different fixative conditions and the immunolabeling results, in which GJVs were positively labeled for anti-VNUT but excitatory CSVs were not, support our model that GJVs contain nucleotides and excitatory CSVs do not. We propose a model in which characteristic GJVs containing nucleotides play an important role in the signal processing in gap junctions of crayfish LGFs. Copyright © 2011 Elsevier Inc. All rights reserved.

Nonlinear Optical Interactions in Semiconductors

DTIC Science & Technology

1984-10-01

TACAN Aerospace Corporation. 6 V. Coupling A. C.N.R.S., Physique du Solide et Energie Solaire We have an on-going interaction with Dr. Christian...optical fiber to the semiconductor sample and back to the analyzing electronics. The band-gap energy of the semiconductor decreases with increasing...temperature. Consequently, the absorption of light in the energy region of the band-gap changes with temperature. From the measured light absorption, the

Nonlinear Optical Interactions in Semiconductors

DTIC Science & Technology

1984-03-16

aU internal audits for TACAN Corporation. 7 V. Coupling A, C. N. R. S., Physique du Solide et Energie Solaire We have an ongoing interaction with Dr...fiber to the semiconductor sample and back to the analyzing electronics. The band gap energy of the semiconductor decreases with increasing tem- perature...Consequently, the absorption of light in the energy region of the band gap changes with temperature. From the measured light absorp- tion, the

Overview On Alternative Asbestos Control Method Research - Nashville, TN

EPA Science Inventory

The alternative asbestos control method (AACM) is an experimental approach to building demolition. Unlike the NESHAP method, the AACM allows some regulated asbestos-containing material to remain in the building and a surfactant-water solution is used to suppress asbestos fibers ...

Overview On Alternative Asbestos Control Method Research - St. Louis, MO

EPA Science Inventory

The alternative asbestos control method (AACM) is an experimental approach to building demolition. Unlike the NESHAP method, the AACM allows some regulated asbestos-containing material to remain in the building and a surfactant-water solution is used to suppress asbestos fibers ...

Overview On Alternative Asbestos Control Method Research - Wisconsin Dells

EPA Science Inventory

The alternative asbestos control method (AACM) is an experimental approach to building demolition. Unlike the NESHAP method, the AACM allows some regulated asbestos containing material to remain in the building and a surfactant-water solution is used to suppress asbestos fibers ...

A State-of-the-Art Review on Soil Reinforcement Technology Using Natural Plant Fiber Materials: Past Findings, Present Trends and Future Directions.

PubMed

Gowthaman, Sivakumar; Nakashima, Kazunori; Kawasaki, Satoru

2018-04-04

Incorporating sustainable materials into geotechnical applications increases day by day due to the consideration of impacts on healthy geo-environment and future generations. The environmental issues associated with conventional synthetic materials such as cement, plastic-composites, steel and ashes necessitate alternative approaches in geotechnical engineering. Recently, natural fiber materials in place of synthetic material have gained momentum as an emulating soil-reinforcement technique in sustainable geotechnics. However, the natural fibers are innately different from such synthetic material whereas behavior of fiber-reinforced soil is influenced not only by physical-mechanical properties but also by biochemical properties. In the present review, the applicability of natural plant fibers as oriented distributed fiber-reinforced soil (ODFS) and randomly distributed fiber-reinforced soil (RDFS) are extensively discussed and emphasized the inspiration of RDFS based on the emerging trend. Review also attempts to explore the importance of biochemical composition of natural-fibers on the performance in subsoil reinforced conditions. The treatment methods which enhances the behavior and lifetime of fibers, are also presented. While outlining the current potential of fiber reinforcement technology, some key research gaps have been highlighted at their importance. Finally, the review briefly documents the future direction of the fiber reinforcement technology by associating bio-mediated technological line.

A State-of-the-Art Review on Soil Reinforcement Technology Using Natural Plant Fiber Materials: Past Findings, Present Trends and Future Directions

PubMed Central

Gowthaman, Sivakumar; Nakashima, Kazunori; Kawasaki, Satoru

2018-01-01

Incorporating sustainable materials into geotechnical applications increases day by day due to the consideration of impacts on healthy geo-environment and future generations. The environmental issues associated with conventional synthetic materials such as cement, plastic-composites, steel and ashes necessitate alternative approaches in geotechnical engineering. Recently, natural fiber materials in place of synthetic material have gained momentum as an emulating soil-reinforcement technique in sustainable geotechnics. However, the natural fibers are innately different from such synthetic material whereas behavior of fiber-reinforced soil is influenced not only by physical-mechanical properties but also by biochemical properties. In the present review, the applicability of natural plant fibers as oriented distributed fiber-reinforced soil (ODFS) and randomly distributed fiber-reinforced soil (RDFS) are extensively discussed and emphasized the inspiration of RDFS based on the emerging trend. Review also attempts to explore the importance of biochemical composition of natural-fibers on the performance in subsoil reinforced conditions. The treatment methods which enhances the behavior and lifetime of fibers, are also presented. While outlining the current potential of fiber reinforcement technology, some key research gaps have been highlighted at their importance. Finally, the review briefly documents the future direction of the fiber reinforcement technology by associating bio-mediated technological line. PMID:29617285

Mental healthcare in Kenya: Exploring optimal conditions for capacity building

PubMed Central

Sands, Natisha; Rolley, John; Ndetei, David; Mansouri, Fethi

2014-01-01

The global burden of disease related to mental disorders is on the increase, with the World Health Organization (WHO) estimating that over 450 million people are affected worldwide. The Mental Health Global Action Program (mhGAP) was launched by the WHO in 2002 in order to address the widening gap in access to mental healthcare in low-income countries. Despite these efforts, access to mental healthcare in low-income countries remains poor and is often described as inadequate, inefficient and inequitable, with an 85% estimated treatment gap in low-income countries, as compared with 35% to 50% in high-income countries.In this article, the authors argue that integrating mental health services into primary healthcare settings through capacity building is vital with regard to achieving mhGAP goals. The article explores the challenges to and potential enablers for the improvement of the delivery of broad-based mental healthcare services in Kenya. The authors propose the integration of the conceptual dimensions of both the cosmopolitanism and capabilities approaches as a combined strategy for dealing with capacity building in heterogeneous settings such as Kenya. PMID:26245443

Mental healthcare in Kenya: exploring optimal conditions for capacity building.

PubMed

Marangu, Elijah; Sands, Natisha; Rolley, John; Ndetei, David; Mansouri, Fethi

2014-10-10

The global burden of disease related to mental disorders is on the increase, with the World Health Organization (WHO) estimating that over 450 million people are affected worldwide. The Mental Health Global Action Program (mhGAP) was launched by the WHO in 2002 in order to address the widening gap in access to mental healthcare in low-income countries. Despite these efforts, access to mental healthcare in low-income countries remains poor and is often described as inadequate, inefficient and inequitable, with an 85% estimated treatment gap in low-income countries, as compared with 35% to 50% in high-income countries.In this article, the authors argue that integrating mental health services into primary healthcare settings through capacity building is vital with regard to achieving mhGAP goals. The article explores the challenges to and potential enablers for the improvement of the delivery of broad-based mental healthcare services in Kenya. The authors propose the integration of the conceptual dimensions of both the cosmopolitanism and capabilities approaches as a combined strategy for dealing with capacity building in heterogeneous settings such as Kenya.

FIBER-TEX 1991: The Fifth Conference on Advanced Engineering Fibers and Textile Structures for Composites

NASA Technical Reports Server (NTRS)

Buckley, John D. (Editor)

1992-01-01

This document is a compilation of papers presented at a joint NASA/North Carolina State University/DoD/Clemson University/Drexel University conference on Fibers, Textile Technology, and Composites Structures held at the College of Textiles Building on Centennial Campus of North Carolina State University, Raleigh, North Carolina on October 15-17, 1991. Conference papers presented information on advanced engineering fibers, textile processes and structures, structural fabric production, mechanics and characteristics of woven composites, pultruded composites, and the latest requirements for the use of textiles in the production of composite materials and structures.

Tapered photonic crystal fiber for simplified Yb:fiber laser frequency comb with low pulse energy and robust f ceo singals.

PubMed

Jiang, Tongxiao; Wang, Aimin; Wang, Guizhong; Zhang, Wei; Niu, Fuzeng; Li, Chen; Zhang, Zhigang

2014-01-27

A tapered silica photonic crystal fiber was designed and fabricated to generate more than one octave spanning supercontinuum (from 550 nm to 1400 nm at -30 dB level), by an input pulse of 40 fs 200 pJ directly from an Yb:fiber ring laser. The low pulse energy spectrum broadening are favorable to generate the high contrast f ceo signals with low noise. The f ceo signal with 40 dB signal-to-noise ratio was detected, which helps to build a compact real-world frequency comb.

Technology Solutions Case Study: Cladding Attachment Over Mineral Fiber Insulation Board

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

None

2015-03-01

Exterior insulating sheathing for high performance building enclosures is an important strategy for meeting energy efficiency requirements in many climates and can position an existing building to perform at the level of best-in-class new construction. Insulation board is also important in high performance building retrofit situations where minimal disruption at the interior is typically desired.

Laboratory to commercial scale - Correlation in the physical properties of biofiber-polymer composites.

USDA-ARS?s Scientific Manuscript database

Bio-fiber polymer composites have been the focus of automotive and building products industries for the last several years. Significant research has been done to improve the processing and performance characteristics of the bio-fiber composite. Most of the initial research is conducted on a small sc...

Recycling of ligno-cellulosic and polyethylene wastes from agricultural operations in thermoplastic composites

USDA-ARS?s Scientific Manuscript database

In the US, wood plastic composites (WPC) represent one of the successful markets for natural fiber-filled thermoplastic composites. The WPC typically use virgin or recycled thermoplastic as the substrate and wood fiber as the filler. A major application of the WPC is in non-structural building appli...

Designing and Integrating a Fiber Optic Network with an Existing Copper Network.

ERIC Educational Resources Information Center

Knapp, Wallace C.

The process that Catonsville Community College (Maryland) went through in moving from a copper to a fiber network is outlined. The discussion addresses the following: describing the need in real terms; building consensus for the project; gaining support by college management; justifying the need for consultant support; writing the request for…

Effects of weathering on color loss of natural fiber thermoplastic composites

Treesearch

R.H. Falk; C. Felton; T. Lundin

2001-01-01

The technology currently exists to manufacture natural fiber thermoplastic composites from recycled materials. Development of commodity-building products from these composites would open up huge markets for waste-based materials in the US. To date, the construction industry has only accepted wood thermoplastic composite lumber (and only for limited applications). In...

Effects of weathering on color loss of natural fiber : thermoplastic composites

Treesearch

Robert H. Falk; Colin Felton; Thomas Lundin

2000-01-01

The technology currently exists to manufacture natural fiber-thermoplastic composites from recycled materials. Development of commodity building products from these composites would open huge markets for waste-based materials in the United States. To date, the construction industry has only accepted wood-thermoplastic composite lumber and only for limited applications...

Interior. Apparatus used in crushing and processing plant fibers to ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Interior. Apparatus used in crushing and processing plant fibers to extract latex from the sap during experiments to find native North American plant which would yield sufficiently high percentage of latex to produce natural rubber. - Thomas A. Edison Laboratories, Building No. 2, Main Street & Lakeside Avenue, West Orange, Essex County, NJ

Overview On Alternative Asbestos Control Method Research: Alternative Methods To Demolition

EPA Science Inventory

The Alternative Asbestos Control Method (AACM) is an experimental approach to building demolition. Unlike the NESHAP method, the AACM allows some regulated asbestos-containing material to remain in the building and a surfactant-water solution is used to suppress asbestos fibers ...

Overview On Alternate Asbestos Control Method Research And NESHAP Comparison - Nashville, TN

EPA Science Inventory

The alternative asbestos control method (AACM) is an experimental approach to building demolition. Unlike the NESHAP method, the AACM allows some regulated asbestos containing material to remain in the building and a surfactant-water solution is used to suppress asbestos fibers ...

Build It Well and the Children Will Come

ERIC Educational Resources Information Center

Kelly, Robert

2009-01-01

When District of Columbia Public Schools (DCPS) Chancellor Michelle Rhee announced that 23 under-enrolled DCPS buildings would close for the 2008/2009 school year, Kathy Padian, Vice President of Building Hope, began talks with the Deputy Mayor of Education in 2007. Building Hope works to close the educational achievement gap by giving students…

Automated fiber pigtailing machine

DOEpatents

Strand, Oliver T.; Lowry, Mark E.

1999-01-01

The Automated Fiber Pigtailing Machine (AFPM) aligns and attaches optical fibers to optoelectonic (OE) devices such as laser diodes, photodiodes, and waveguide devices without operator intervention. The so-called pigtailing process is completed with sub-micron accuracies in less than 3 minutes. The AFPM operates unattended for one hour, is modular in design and is compatible with a mass production manufacturing environment. This machine can be used to build components which are used in military aircraft navigation systems, computer systems, communications systems and in the construction of diagnostics and experimental systems.

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

Drake, G.; Garcia-Scivres, M.; Paramonov, A.

We propose to use silicon photonics technology to build radiation-hard fiber-optic links for high-bandwidth readout of tracking detectors. The CMOS integrated silicon photonics was developed by Luxtera and commercialized by Molex. The commercial off-the-shelf (COTS) fiber-optic links feature moderate radiation tolerance insufficient for trackers. A transceiver contains four RX and four TX channels operating at 10 Gbps each. The next generation will likely operate at 25 Gbps per channel. The approach uses a standard CMOS process and single-mode fibers, providing low power consumption and good scalability and reliability.

Robust optical fiber patch-cords for in vivo optogenetic experiments in rats.

PubMed

Trujillo-Pisanty, Ivan; Sanio, Christian; Chaudhri, Nadia; Shizgal, Peter

2015-01-01

In vivo optogenetic experiments commonly employ long lengths of optical fiber to connect the light source (commonly a laser) to the optical fiber implants in the brain. Commercially available patch cords are expensive and break easily. Researchers have developed methods to build these cables in house for in vivo experiments with rodents [1-4]. However, the half-life of those patch cords is greatly reduced when they are used with behaving rats, which are strong enough to break the delicate cable tip and to bite through the optical fiber and furcation tubing. Based on [3] we have strengthened the patch-cord tip that connects to the optical implant, and we have incorporated multiple layers of shielding to produce more robust and resistant cladding. Here, we illustrate how to build these patch cords with FC or M3 connectors. However, the design can be adapted for use with other common optical-fiber connectors. We have saved time and money by using this design in our optical self-stimulation experiments with rats, which are commonly several months long and last four to eleven hours per session. The main advantages are: •Long half-life.•Resistant to moderate rodent bites.•Suitable for long in vivo optogenetic experiments with large rodents.

Novel route of synthesis for cellulose fiber-based hybrid polyurethane

NASA Astrophysics Data System (ADS)

Ikhwan, F. H.; Ilmiati, S.; Kurnia Adi, H.; Arumsari, R.; Chalid, M.

2017-07-01

Polyurethanes, obtained by the reaction of a diisocyanate compound with bifunctional or multifunctional reagent such as diols or polyols, have been studied intensively and well developed. The wide range modifier such as chemical structures and molecular weight to build polyurethanes led to designs of materials that may easily meet the functional product demand and to the extraordinary spreading of these materials in market. Properties of the obtained polymer are related to the chemical structure of polyurethane backbone. A number polyurethanes prepared from biomass-based monomers have been reported. Cellulose fiber, as a biomass material is containing abundant hydroxyl, promising material as chain extender for building hybrid polyurethanes. In previous researches, cellulose fiber was used as filler in synthesis of polyurethane composites. This paper reported a novel route of hybrid polyurethane synthesis, which a cellulose fiber was used as chain extender. The experiment performed by reacting 4,4’-Methylenebis (cyclohexyl isocyanate) (HMDI) and polyethylene glycol with variation of molecular weight to obtained pre-polyurethane, continued by adding micro fiber cellulose (MFC) with variation of type and composition in the mixture. The experiment was evaluated by NMR, FTIR, SEM and STA measurement. NMR and FTIR confirmed the reaction of the hybrid polyurethane. STA showed hybrid polyurethane has good thermal stability. SEM showed good distribution and dispersion of sorghum-based MFC.

Fiber in the Local Loop: The Role of Electric Utilities

NASA Astrophysics Data System (ADS)

Meehan, Charles M.

1990-01-01

Electric utilities are beginning to make heavy use of fiber for a number of applications beyond transmission of voice and data among operating centers and plant facilities which employed fiber on the electric transmission systems. These additional uses include load management and automatic meter reading. Thus, utilities are beginning to place fiber on the electric distribution systems which, in many cases covers the same customer base as the "local loop". This shift to fiber on the distribution system is due to the advantages offered by fiber and because of congestion in the radio bands used for load management. This shift to fiber has been facilitated by a regulatory policy permitting utilities to lease reserve capacity on their fiber systems on an unregulated basis. This, in turn, has interested electric utilities in building fiber to their residential and commercial customers for voice, data and video. This will also provide for sophisticated load management systems and, possibly, generation of revenue.

Automated atlas-based clustering of white matter fiber tracts from DTMRI.

PubMed

Maddah, Mahnaz; Mewes, Andrea U J; Haker, Steven; Grimson, W Eric L; Warfield, Simon K

2005-01-01

A new framework is presented for clustering fiber tracts into anatomically known bundles. This work is motivated by medical applications in which variation analysis of known bundles of fiber tracts in the human brain is desired. To include the anatomical knowledge in the clustering, we invoke an atlas of fiber tracts, labeled by the number of bundles of interest. In this work, we construct such an atlas and use it to cluster all fiber tracts in the white matter. To build the atlas, we start with a set of labeled ROIs specified by an expert and extract the fiber tracts initiating from each ROI. Affine registration is used to project the extracted fiber tracts of each subject to the atlas, whereas their B-spline representation is used to efficiently compare them to the fiber tracts in the atlas and assign cluster labels. Expert visual inspection of the result confirms that the proposed method is very promising and efficient in clustering of the known bundles of fiber tracts.

Enhanced photocatalytic activity of wool fibers having titanium dioxide nanoparticles formed inside their cortex

NASA Astrophysics Data System (ADS)

Zhang, Hui; Sun, Runjun; Wu, Hailiang; Mao, Ningtao

2018-07-01

A wool-TiO2 nanoparticle composite material having TiO2 nanoparticles both infiltrated in the matrix between macrofibrils inside cortical cells of wool fibers and grafted on the fiber surface is obtained in this study, and the wool-nanoparticle composite material is found to have highly photocatalytic activities with an extremely narrow band gap of 2.8 eV. The wool fibers are obtained using three successive technical steps: wool fibers are swollen by using lithium bromide, then saturated with tetrabutyl titanate ethanol solution and subsequently treated in boiling water. It was demonstrated that the chemical bonds formed between the as-synthesized TiO2 nanoparticles and the wool fibers swollen by lithium bromide include C‑Ti4+(Ti3+), N‑Ti4+(Ti3+), O‑Ti3+, and S‑Ti4+(Ti3+) bonds. The modified wool fibers have shown markedly improved photocatalytic efficiency due to their enhanced visible light absorption capability, which is much better than the (N-doped) TiO2 coated wool fibers. In contrast, TiO2 modified wool fibers swollen by using formic acid have poorer photoactivity, this might be due to the elimination of trivalent titanium between TiO2 nanoparticles and the wool fibers.

Enhanced photocatalytic activity of wool fibers having titanium dioxide nanoparticles formed inside their cortex.

PubMed

Zhang, Hui; Sun, Runjun; Wu, Hailiang; Mao, Ningtao

2018-05-01

A wool-TiO2 nanoparticle composite material having TiO2 nanoparticles both infiltrated in the matrix between macrofibrils inside cortical cells of wool fibers and grafted on the fiber surface is obtained in this study, and the wool-nanoparticle composite material is found to have highly photocatalytic activities with an extremely narrow band gap of 2.8 eV. The wool fibers are obtained using three successive technical steps: wool fibers are swollen by using lithium bromide, then saturated with tetrabutyl titanate ethanol solution and subsequently treated in boiling water. It was demonstrated that the chemical bonds formed between the as-synthesized TiO2 nanoparticles and the wool fibers swollen by lithium bromide include C-Ti4+(Ti3+), N-Ti4+(Ti3+), O-Ti3+, and S-Ti4+(Ti3+) bonds. The modified wool fibers have shown markedly improved photocatalytic efficiency due to their enhanced visible light absorption capability, which is much better than the (N-doped) TiO2 coated wool fibers. In contrast, TiO2 modified wool fibers swollen by using formic acid have poorer photoactivity, this might be due to the elimination of trivalent titanium between TiO2 nanoparticles and the wool fibers. © 2018 IOP Publishing Ltd.

Mode instability in a Yb-doped stretched core fiber

NASA Astrophysics Data System (ADS)

Xia, N.; Yoo, S.

2017-02-01

In this work we present the theoretical study of transverse mode instability (TMI) in ytterbium (Yb)-doped rectangular core fibers with different core aspect ratios using the fast Fourier transform (FFT) beam propagation method (BPM). As expected, the rectangular core fiber with larger aspect ratio (AR.) offers more efficient heat dissipation than a circular core fiber. However, it is found that the rectangular core fiber does not benefit from the better heat dissipation to suppress the TMI when compared to the circular core counterpart. The temperature building in the rectangular core fiber decreases by up to 24.6% with a 10:1 aspect ratio core, while threshold pump power drops by up to 38.3% when compared with a circular core fiber with the same core area. Our study reveals that a smaller effective refractive index difference between modes and a weaker gain saturation effect compensate the thermal advantage from more efficient heat dissipation.

Fiber and colorectal diseases: Separating fact from fiction

PubMed Central

Tan, Kok-Yang; Seow-Choen, Francis

2007-01-01

Whilst fruits and vegetables are an essential part of our dietary intake, the role of fiber in the prevention of colorectal diseases remains controversial. The main feature of a high-fiber diet is its poor digestibility. Soluble fiber like pectins, guar and ispaghula produce viscous solutions in the gastrointestinal tract delaying small bowel absorption and transit. Insoluble fiber, on the other hand, pass largely unaltered through the gut. The more fiber is ingested, the more stools will have to be passed. Fermentation in the intestines results in build up of large amounts of gases in the colon. This article reviews the physiology of ingestion of fiber and defecation. It also looks into the impact of dietary fiber on various colorectal diseases. A strong case cannot be made for a protective effect of dietary fiber against colorectal polyp or cancer. Neither has fiber been found to be useful in chronic constipation and irritable bowel syndrome. It is also not useful in the treatment of perianal conditions. The fiber deficit - diverticulosis theory should also be challenged. The authors urge clinicians to keep an open mind about fiber. One must be aware of the truths and myths about fiber before recommending it. PMID:17696243

Fiber and colorectal diseases: separating fact from fiction.

PubMed

Tan, Kok-Yang; Seow-Choen, Francis

2007-08-21

Whilst fruits and vegetables are an essential part of our dietary intake, the role of fiber in the prevention of colorectal diseases remains controversial. The main feature of a high-fiber diet is its poor digestibility. Soluble fiber like pectins, guar and ispaghula produce viscous solutions in the gastrointestinal tract delaying small bowel absorption and transit. Insoluble fiber, on the other hand, pass largely unaltered through the gut. The more fiber is ingested, the more stools will have to be passed. Fermentation in the intestines results in build up of large amounts of gases in the colon. This article reviews the physiology of ingestion of fiber and defecation. It also looks into the impact of dietary fiber on various colorectal diseases. A strong case cannot be made for a protective effect of dietary fiber against colorectal polyp or cancer. Neither has fiber been found to be useful in chronic constipation and irritable bowel syndrome. It is also not useful in the treatment of perianal conditions. The fiber deficit - diverticulosis theory should also be challenged. The authors urge clinicians to keep an open mind about fiber. One must be aware of the truths and myths about fiber before recommending it.

Recent development in blast performance of fiber-reinforced concrete

NASA Astrophysics Data System (ADS)

Hajek, R.; Foglar, M.; Kohoutkova, A.

2017-09-01

The paper presents an overview of the recent development in blast performance of fiber reinforced concrete. The paper builds on more than ten years’ history of the research in this field by the team of the Department of Concrete and Masonry Structures of the Faculty of Civil Engineering of the Czech Technical University in Prague.

24 CFR 200.946 - Building product standards and certification program for exterior finish and insulation systems...

Code of Federal Regulations, 2012 CFR

2012-04-01

...) ASTM C-1186-91 Standard Specification for Flat Non-Asbestos Fiber-Cement Sheets. (v) ASTM D 579-90 Standard Specification for Greige Woven Glass Fabrics. (vi) ASTM D 3273-86—(Reapproved 1991) Standard Test... Glass Fiber Reinforcing Mesh for Use in Exterior Insulation and Finish Systems (EIFS), Class PB. (xv...

24 CFR 200.946 - Building product standards and certification program for exterior finish and insulation systems...

Code of Federal Regulations, 2014 CFR

2014-04-01

...) ASTM C-1186-91 Standard Specification for Flat Non-Asbestos Fiber-Cement Sheets. (v) ASTM D 579-90 Standard Specification for Greige Woven Glass Fabrics. (vi) ASTM D 3273-86—(Reapproved 1991) Standard Test... Glass Fiber Reinforcing Mesh for Use in Exterior Insulation and Finish Systems (EIFS), Class PB. (xv...

24 CFR 200.946 - Building product standards and certification program for exterior finish and insulation systems...

Code of Federal Regulations, 2013 CFR

2013-04-01

...) ASTM C-1186-91 Standard Specification for Flat Non-Asbestos Fiber-Cement Sheets. (v) ASTM D 579-90 Standard Specification for Greige Woven Glass Fabrics. (vi) ASTM D 3273-86—(Reapproved 1991) Standard Test... Glass Fiber Reinforcing Mesh for Use in Exterior Insulation and Finish Systems (EIFS), Class PB. (xv...

Fabrication and photoluminescence properties of graphite fiber/ZnO nanorod core-shell structures.

PubMed

Liu, Xianbin; Du, Hejun; Liu, Bo; Wang, Jianxiong; Sun, Xiao Wei; Sun, Handong

2011-08-01

Graphite fiber/ZnO nanorod core-shell structures were synthesized by thermal evaporation process. The core-shell hybrid architectures were comprised of ZnO nanorods grown on the surface of graphite fiber. In addition, Hollow ZnO hierarchical structure can be obtained by oxidizing the graphite fiber. Room temperature photoluminescence (PL) of the as-made graphite fiber/ZnO nanorod structures shows two UV peaks at around 3.274 eV and 3.181 eV. The temperature-dependent photoluminescence spectra demonstrate the two UV emissions are attributed to the intrinsic optical transitions and extrinsic defect-related emissions in ZnO. These hybrid structures may be used as the building block for fabrication of nanodevices.

Research of movement process of fiber suspension in accelerating unit of wet grinding disintegrator

NASA Astrophysics Data System (ADS)

Mykhaylichenko, S. A.; Dubinin, N. N.; Kachaev, A. E.; Goncharov, S. I.; Farafonov, A. A.

2018-03-01

At the present stage of development of building material science, products reinforced with fibers of various origin (mineral, organic, metal and others) are commonly used. Determination of the optimal structure and the chemical composition of the fiber depends on a number of requirements for filler, binder, and other miscellaneous additives, etc. The rational combination of physical and chemical composition of the primary matrix of the product (e.g., binders, cement) with dispersion of anisotropic fiber of filler not only contributes to the strength of products, but also stabilizes their internal structure: prevents the occurrence of internal stress of the cement stone, increases the adhesive interaction of particles of cement at the contact boundary with fibers, etc.

Fiber-coupled THz spectroscopy for monitoring polymeric compounding processes

NASA Astrophysics Data System (ADS)

Vieweg, N.; Krumbholz, N.; Hasek, T.; Wilk, R.; Bartels, V.; Keseberg, C.; Pethukhov, V.; Mikulics, M.; Wetenkamp, L.; Koch, M.

2007-06-01

We present a compact, robust, and transportable fiber-coupled THz system for inline monitoring of polymeric compounding processes in an industrial environment. The system is built on a 90cm x 90cm large shock absorbing optical bench. A sealed metal box protects the system against dust and mechanical disturbances. A closed loop controller unit is used to ensure optimum coupling of the laser beam into the fiber. In order to build efficient and stable fiber-coupled antennas we glue the fibers directly onto photoconductive switches. Thus, the antenna performance is very stable and it is secured from dust or misalignment by vibrations. We discuss fabrication details and antenna performance. First spectroscopic data obtained with this system is presented.

Gate-to-gate Life-Cycle Inventory of Hardboard Production in North America

Treesearch

Richard Bergman

2014-01-01

Whole-building life-cycle assessments (LCAs) populated by life-cycle inventory (LCI) data are incorporated into environmental footprint software tools for establishing green building certification by building professionals and code. However, LCI data on some wood building products are still needed to help fill gaps in the data and thus provide a more complete picture...

Structural Health Monitoring of Civil Infrastructure Using Optical Fiber Sensing Technology: A Comprehensive Review

PubMed Central

Ye, X. W.; Su, Y. H.; Han, J. P.

2014-01-01

In the last two decades, a significant number of innovative sensing systems based on optical fiber sensors have been exploited in the engineering community due to their inherent distinctive advantages such as small size, light weight, immunity to electromagnetic interference (EMI) and corrosion, and embedding capability. A lot of optical fiber sensor-based monitoring systems have been developed for continuous measurement and real-time assessment of diversified engineering structures such as bridges, buildings, tunnels, pipelines, wind turbines, railway infrastructure, and geotechnical structures. The purpose of this review article is devoted to presenting a summary of the basic principles of various optical fiber sensors, innovation in sensing and computational methodologies, development of novel optical fiber sensors, and the practical application status of the optical fiber sensing technology in structural health monitoring (SHM) of civil infrastructure. PMID:25133250

Structural health monitoring of civil infrastructure using optical fiber sensing technology: a comprehensive review.

PubMed

Ye, X W; Su, Y H; Han, J P

2014-01-01

In the last two decades, a significant number of innovative sensing systems based on optical fiber sensors have been exploited in the engineering community due to their inherent distinctive advantages such as small size, light weight, immunity to electromagnetic interference (EMI) and corrosion, and embedding capability. A lot of optical fiber sensor-based monitoring systems have been developed for continuous measurement and real-time assessment of diversified engineering structures such as bridges, buildings, tunnels, pipelines, wind turbines, railway infrastructure, and geotechnical structures. The purpose of this review article is devoted to presenting a summary of the basic principles of various optical fiber sensors, innovation in sensing and computational methodologies, development of novel optical fiber sensors, and the practical application status of the optical fiber sensing technology in structural health monitoring (SHM) of civil infrastructure.

One isoform of Arg/Abl2 tyrosine kinase is nuclear and the other seven cytosolic isoforms differently modulate cell morphology, motility and the cytoskeleton

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

Bianchi, Cristina; Torsello, Barbara; Di Stefano, Vitalba

The non-receptor tyrosine kinase Abelson related gene (Arg/Abl2) regulates cell migration and morphogenesis by modulating the cytoskeleton. Arg promotes actin-based cell protrusions and spreading, and inhibits cell migration by attenuating stress fiber formation and contractility via activation of the RhoA inhibitor, p190RhoGAP, and by regulating focal adhesion dynamics also via CrkII phosphorylation. Eight full-length Arg isoforms with different N- and C-termini are endogenously expressed in human cells. In this paper, the eight Arg isoforms, subcloned in the pFLAG-CMV2 vector, were transfected in COS-7 cells in order to study their subcellular distribution and role in cell morphology, migration and cytoskeletal modulation.more » The transfected 1BSCTS Arg isoform has a nuclear distribution and phosphorylates CrkII in the nucleus, whilst the other isoforms are detected in the cytoplasm. The 1BLCTL, 1BSCTL, 1ASCTS isoforms were able to significantly decrease stress fibers, induce cell shrinkage and filopodia-like protrusions with a significant increase in p190RhoGAP phosphorylation. In contrast, 1ALCTL, 1ALCTS, 1ASCTL and 1BLCTS isoforms do not significantly decrease stress fibers and induce the formation of retraction tail-like protrusions. The 1BLCTL and 1ALCTL isoforms have different effects on cell migration and focal adhesions. All these data may open new perspectives to study the mechanisms of cell invasiveness. -Highlights: • Each of the eight Arg isoforms was transfected in COS-7 cells. • Only the 1BSCTS Arg isoform has a nuclear distribution in transfected cells. • The cytoplasmic isoforms and F-actin colocalize cortically and in cell protrusions. • Arg isoforms differently phosphorylate p190RhoGAP and CrkII. • Arg isoforms differently modulate stress fibers, cell protrusions and motility.« less

Architectures of fiber optic network in telecommunications

NASA Astrophysics Data System (ADS)

Vasile, Irina B.; Vasile, Alexandru; Filip, Luminita E.

2005-08-01

The operators of telecommunications have targeted their efforts towards realizing applications using broad band fiber optics systems in the access network. Thus, a new concept related to the implementation of fiber optic transmission systems, named FITL (Fiber In The Loop) has appeared. The fiber optic transmission systems have been extensively used for realizing the transport and intercommunication of the public telecommunication network, as well as for assuring the access to the telecommunication systems of the great corporations. Still, the segment of the residential users and small corporations did not benefit on large scale of this technology implementation. For the purpose of defining fiber optic applications, more types of architectures were conceived, like: bus, ring, star, tree. In the case of tree-like networks passive splitters (that"s where the name of PON comes from - Passive Optical Network-), which reduce significantly the costs of the fiber optic access, by separating the costs of the optical electronic components. That's why the passive fiber optics architectures (PON represent a viable solution for realizing the access at the user's loop. The main types of fiber optics architectures included in this work are: FTTC (Fiber To The Curb); FTTB (Fiber To The Building); FTTH (Fiber To The Home).

Effects of high-speed homogenization and high-pressure homogenization on structure of tomato residue fibers.

PubMed

Hua, Xiao; Xu, Shanan; Wang, Mingming; Chen, Ying; Yang, Hui; Yang, Ruijin

2017-10-01

Tomato residue fibers obtained after derosination and deproteinization were processed by high-speed homogenization (HSH) and high-pressure homogenization (HPH), and their effects on fiber structure was investigated, respectively. Characterizations including particle size distribution, SEM, TEM and XRD were performed. HSH could break raw fibers to small particles of around 60μm, while HPH could reshape fibers to build network structure. Microfibrils were released and their nanostructure consisting of elementary fibrils was observed by TEM. XRD patterns indicated both HSH and HPH could hardly alter the nanostructure of the fibers. Physicochemical properties including expansibility, WHC and OHC were determined. Both HSH and HPH could increase the soluble fiber content by about 8%, but HSH-HPH combined processing did not show better result. Acid (4mol/L HCl) was used in replacement of water medium and the acidic degradation of fibers could be promoted by high speed shearing or high pressure processing. Copyright © 2017 Elsevier Ltd. All rights reserved.

Investigations on Thermal Conductivities of Jute and Banana Fiber Reinforced Epoxy Composites

NASA Astrophysics Data System (ADS)

Pujari, Satish; Ramakrishna, Avasarala; Balaram Padal, Korabu Tulasi

2017-04-01

The Jute and Banana fibers are used as reinforcement in epoxy resin matrix for making partially green biodegradable material composite via hand lay-up technique. The thermal conductivity of the jute fiber epoxy composites and banana fiber epoxy composites at different volume fraction of the fiber is determined experimentally by using guarded heat flow meter method. The experimental results had shown that thermal conductivity of the composites decrease with an increase in the fiber content. Experimental results are compared with theoretical models (Series model, Hashin model and Maxwell model) to describe the variation of the thermal conductivity versus the volume fraction of the fiber. Good agreement between theoretical and experimental results is observed. Thermal conductivity of Banana fiber composite is less when compared to that of Jute composite which indicates banana is a good insulator and also the developed composites can be used as insulating materials in building, automotive industry and in steam pipes to save energy by reducing rate of heat transfer.

Stabilization, Rolling, and Addition of Other Extracellular Matrix Proteins to Collagen Hydrogels Improve Regeneration in Chitosan Guides for Long Peripheral Nerve Gaps in Rats.

PubMed

Gonzalez-Perez, Francisco; Cobianchi, Stefano; Heimann, Claudia; Phillips, James B; Udina, Esther; Navarro, Xavier

2017-03-01

Autograft is still the gold standard technique for the repair of long peripheral nerve injuries. The addition of biologically active scaffolds into the lumen of conduits to mimic the endoneurium of peripheral nerves may increase the final outcome of artificial nerve devices. Furthermore, the control of the orientation of the collagen fibers may provide some longitudinal guidance architecture providing a higher level of mesoscale tissue structure. To evaluate the regenerative capabilities of chitosan conduits enriched with extracellular matrix-based scaffolds to bridge a critical gap of 15 mm in the rat sciatic nerve. The right sciatic nerve of female Wistar Hannover rats was repaired with chitosan tubes functionalized with extracellular matrix-based scaffolds fully hydrated or stabilized and rolled to bridge a 15 mm nerve gap. Recovery was evaluated by means of electrophysiology and algesimetry tests and histological analysis 4 months after injury. Stabilized constructs enhanced the success of regeneration compared with fully hydrated scaffolds. Moreover, fibronectin-enriched scaffolds increased muscle reinnervation and number of myelinated fibers compared with laminin-enriched constructs. A mixed combination of collagen and fibronectin may be a promising internal filler for neural conduits for the repair of peripheral nerve injuries, and their stabilization may increase the quality of regeneration over long gaps. Copyright © 2017 by the Congress of Neurological Surgeons

Photonic crystal fiber in-line Mach-Zehnder interferometer for explosive detection.

PubMed

Tao, Chuanyi; Wei, Heming; Feng, Wenlin

2016-02-08

We report a photonic crystal fiber (PCF) in-line Mach-Zehnder interferometer used as a gas sensor device which exhibits high sensitivity to the explosive trinitrotoluene (TNT). The interferometric sensor head is formed by embedding a segment of large-mode-area/grapefruit PCF between standard single-mode fibers via butt coupling, which produces two small air gaps in between terminated fiber ends with ceramic ferrule connectors as coupling regions, which also serve as inlet/outlet for the gas. The spectral response of the interferometer is investigated in terms of its wavelength spectrum. The selectivity to TNT vapor is achieved by immobilizing a molecular recognition ployallylamine layer on the inner surface of the holey region of the PCF. The TNT-induced variations of the interference fringes are measured and the sensing capability of the proposed sensor is demonstrated experimentally.

Cellulosic building insulation versus mineral wool, fiberglass or perlite: installer's exposure by inhalation of fibers, dust, endotoxin and fire-retardant additives.

PubMed

Breum, N O; Schneider, T; Jørgensen, O; Valdbjørn Rasmussen, T; Skibstrup Eriksen, S

2003-11-01

A task-specific exposure matrix was designed for workers installing building insulation materials. A priori, a matrix element was defined by type of task (installer or helper), type of work area (attic spaces or wall cavities) and type of insulation material (slabs from mineral wool, fiberglass or flax; loose-fill cellulosic material or perlite). In the laboratory a mock-up (full scale) of a one-family house was used for simulated installation of insulation materials (four replicates per matrix element). Personal exposure to dust and fibers was measured. The dust was analyzed for content of endotoxin and some trace elements (boron and aluminum) from fire-retardant or mold-resistant additives. Fibers were characterized as WHO fibers or non-WHO fibers. In support of the exposure matrix, the dustiness of all the materials was measured in a rotating drum tester. For installers in attic spaces, risk of exposure was low for inhalation of dust and WHO fibers from slab materials of mineral wool or fiberglass. Slab materials from flax may cause high risk of exposure to endotoxin. The risk of exposure by inhalation of dust from loose-fill materials was high for installers in attic spaces and for some of the materials risk of exposure was high for boron and aluminum. Exposure by inhalation of cellulosic WHO fibers was high but little is known about the health effects and a risk assessment is not possible. For the insulation of walls, the risk of installers' exposure by inhalation of dust and fibers was low for the slab materials, while a high risk was observed for loose-fill materials. The exposure to WHO fibers was positively correlated to the dust exposure. A dust level of 6.1 mg/m3 was shown to be useful as a proxy for screening exposure to WHO fibers in excess of 10(6) fibers/m3. In the rotating drum, slabs of insulation material from mineral wool or fiberglass were tested as not dusty. Cellulosic loose-fill materials were tested as very dusty, and perlite proved to be extremely dusty.

K-8 Charter Schools: Closing the Achievement Gap. Innovations in Education

ERIC Educational Resources Information Center

US Department of Education, 2007

2007-01-01

This guide is part of a series produced by the U.S. Department of Education, and it builds on two previous works: "Successful Charter Schools" (ED493615) and "Charter High Schools Closing the Achievement Gap" (ED494482). It profiles seven K-8 charter schools that are making headway in narrowing gaps in achievement. It examines…

Building a Digital Workforce. Part 2: Reaching Out to Underserved Communities. NPA Report.

ERIC Educational Resources Information Center

2002

The Digital Economic Opportunity Committee (DEOC) was established to examine the information technology (IT) skills gap and make recommendations to eliminate this gap. DEOC believed the appropriate response to this skills gap is two-fold. The first was upgrading existing workers skills through training. The second was expanding the number of…

Effects of vibratory microscreening on proximate composition and recovery of poultry processing wastewater particulate matter.

PubMed

Kiepper, B H; Merka, W C; Fletcher, D L

2008-12-01

Experiments were conducted to compare the effects of tertiary microscreen gap size on the proximate composition and rate of recovery of particulate matter from poultry processing wastewater (PPW). A high-speed vibratory screen was installed within the wastewater treatment area of a southeast US broiler slaughter plant after the existing primary and secondary mechanical rotary screens. Microscreen panels with nominal gap size openings of 212, 106 and 45mum were investigated. The particulate matter samples recovered were subjected to proximate analysis to determine percent moisture, fat, protein, crude fiber and ash. The average percent wet weight moisture (%WW) content for all samples was 79.1. The average percent dry matter (%DM) fat, protein, crude fiber and ash were 63.5, 17.5, 4.8 and 1.5, respectively. The mean concentration of total solids (TS) recovered from all microscreen runs was 668mg/L, which represents a potential additional daily offal recovery rate of 12.1metric tons (MT) per 3.78 million L (1.0 million gallons US) of PPW. There was no significant difference in the performance of the three microscreen gap sizes with regard to proximate composition or mass of particulate matter recovered.

Overexpression of GAP-43 reveals unexpected properties of hippocampal mossy fibers.

PubMed

Rekart, Jerome L; Routtenberg, Aryeh

2010-01-01

The mossy fiber (MF) system targets the apical dendrites of CA3 pyramidal cells in the stratum lucidum (SL). In mice overexpressing the growth-associated protein GAP-43 there is an apparent ectopic growth of these MFs into the stratum oriens (SO) targeting the basal dendrites of these same pyramidal cells (Aigner et al. (1995) Cell 83:269-278). This is the first evidence to our knowledge that links increased GAP-43 expression with growth of central axons. Here we studied the Aigner et al. transgenic mice but were unable to confirm such growth into SO. However, using quantitative methods we did observe enhanced growth within the regions normally targeted by MFs, for example, the SL in the CA3a region. These contrasting results led us to study MFs with double-immunostaining using an immunohistochemical marker for MFs, the zinc transporter, ZnT3, to visualize the colocalization of transgenic GAP-43 within MFs. Unexpectedly, using both fluorescence and confocal microscopy, we were unable to detect colocalization of GAP-43-positive axons with ZnT3-positive MF axons within the MF pathways, either in the region of the MF axons or in the SL, where MF terminals are abundant. In contrast, the plasma membrane-associated presynaptic marker SNAP-25 did colocalize with transgenic GAP-43-positive terminals in the SL. Synaptophysin, the vesicle-associated presynaptic terminal marker, colocalized with ZnT3 but did not appear to colocalize with GAP-43. The present findings raise important questions about the properties of granule cells and the MF mechanisms that differentially regulate axonal remodeling in the adult hippocampus: (1) Because there appears to be at least two populations of granule cells defined by their differential protein expression, this points to the existence of an intrinsic heterogeneity of granule cell expression beyond that contributed by adult neurogenesis; (2) Giventhe present evidence that growth is induced in mice overexpressing GAP-43 in adjacent non-GAP-43 containing MFs, the potential exists for a heretofore unexplored interaxonal communication mechanism. Copyright 2009 Wiley-Liss, Inc.

NRL Review, 2002

DTIC Science & Technology

2002-05-01

technology for polarization-maintaining fiber amplification and an ultrashort pulsed fiber laser to Calmar Optcom. Calmar Optcom will be manufacturing...June 1995. This facility is made up of 56 laser beams and is single pulsed (4 nanosecond pulse ). This facil- ity provides intense radiation for studying...plasma interactions, in- tense laser -electron beam interactions, and intense laser -matter interactions. The division is building a repetitively pulsed (5

Automated fiber pigtailing machine

DOEpatents

Strand, O.T.; Lowry, M.E.

1999-01-05

The Automated Fiber Pigtailing Machine (AFPM) aligns and attaches optical fibers to optoelectronic (OE) devices such as laser diodes, photodiodes, and waveguide devices without operator intervention. The so-called pigtailing process is completed with sub-micron accuracies in less than 3 minutes. The AFPM operates unattended for one hour, is modular in design and is compatible with a mass production manufacturing environment. This machine can be used to build components which are used in military aircraft navigation systems, computer systems, communications systems and in the construction of diagnostics and experimental systems. 26 figs.

Assessment of the risk due to release of carbon fiber in civil aircraft accidents, phase 2

NASA Technical Reports Server (NTRS)

Pocinki, L.; Cornell, M. E.; Kaplan, L.

1980-01-01

The risk associated with the potential use of carbon fiber composite material in commercial jet aircraft is investigated. A simulation model developed to generate risk profiles for several airports is described. The risk profiles show the probability that the cost due to accidents in any year exceeds a given amount. The computer model simulates aircraft accidents with fire, release of fibers, their downwind transport and infiltration of buildings, equipment failures, and resulting ecomomic impact. The individual airport results were combined to yield the national risk profile.

Color tunable photonic textiles for wearable display applications

NASA Astrophysics Data System (ADS)

Sayed, I.; Berzowska, J.; Skorobogatiy, M.

2010-04-01

Integration of optical functionalities such as light emission, processing and collection into flexible woven matrices of fabric have grabbed a lot of attention in the last few years. Photonic textiles frequently involve optical fibers as they can be easily processed together with supporting fabric fibers. This technology finds uses in various fields of application such as interactive clothing, signage, wearable health monitoring sensors and mechanical strain and deformation detectors. Recent development in the field of Photonic Band Gap optical fibers (PBG) could potentially lead to novel photonic textiles applications and techniques. Particularly, plastic PBG Bragg fibers fabricated in our group have strong potential in the field of photonic textiles as they offer many advantages over standard silica fibers at the same low cost. Among many unusual properties of PBG textiles we mention that they are highly reflective, PBG textiles are colored without using any colorants, PBG textiles can change their color by controlling the relative intensities of guided and reflected light, and finally, PBG textiles can change their colors when stretched. Some of the many experimental realization of photonic bandgap fiber textiles and their potential applications in wearable displays are discussed.

Three-Dimensional Printed Thermal Regulation Textiles.

PubMed

Gao, Tingting; Yang, Zhi; Chen, Chaoji; Li, Yiju; Fu, Kun; Dai, Jiaqi; Hitz, Emily M; Xie, Hua; Liu, Boyang; Song, Jianwei; Yang, Bao; Hu, Liangbing

2017-11-28

Space cooling is a predominant part of energy consumption in people's daily life. Although cooling the whole building is an effective way to provide personal comfort in hot weather, it is energy-consuming and high-cost. Personal cooling technology, being able to provide personal thermal comfort by directing local heat to the thermally regulated environment, has been regarded as one of the most promising technologies for cooling energy and cost savings. Here, we demonstrate a personal thermal regulated textile using thermally conductive and highly aligned boron nitride (BN)/poly(vinyl alcohol) (PVA) composite (denoted as a-BN/PVA) fibers to improve the thermal transport properties of textiles for personal cooling. The a-BN/PVA composite fibers are fabricated through a fast and scalable three-dimensional (3D) printing method. Uniform dispersion and high alignment of BN nanosheets (BNNSs) can be achieved during the processing of fiber fabrication, leading to a combination of high mechanical strength (355 MPa) and favorable heat dispersion. Due to the improved thermal transport property imparted by the thermally conductive and highly aligned BNNSs, better cooling effect (55% improvement over the commercial cotton fiber) can be realized in the a-BN/PVA textile. The wearable a-BN/PVA textiles containing the 3D-printed a-BN/PVA fibers offer a promising selection for meeting the personal cooling requirement, which can significantly reduce the energy consumption and cost for cooling the whole building.

Performance Using Bamboo Fiber Ash Concrete as Admixture Adding Superplasticizer

NASA Astrophysics Data System (ADS)

Vasudevan, Gunalaan

2017-06-01

The increasing demand on natural resources for housing provisions in developing countries have called for sourcing and use of sustainable local materials for building and housing delivery. Natural materials to be considered sustainable for building construction should be ‘green’ and obtained from local sources, including rapidly renewable plant materials like palm fronds and bamboo, recycled materials and other products that are reusable and renewable. Each year, tens of millions of tons of bamboo are utilized commercially, generating a vast amount of waste. Besides that, bamboo fiber is easy availability, low density, low production cost and satisfactory mechanical properties. One solution is to activate this waste by using it as an additive admixture in concrete to keep it out of landfills and save money on waste disposal. The research investigates the mechanical and physical properties of bamboo fiber powder in a blended Portland cement. The structural value of the bamboo fiber powder in a blended Portland cement was evaluated with consideration for its suitability in concrete. Varied percentage of bamboo fiber powder (BFP) at 0%, 5%, 10%, 15%, and 20% as an admixture in 1:2:4 concrete mixes. The workability of the mix was determined through slump; standard consistency test was carried on the cement. Compressive strength of hardened cured (150 x 150 x 150) mm concrete cubes at 7days, 14days and 28days were tested.

Strength and deformability of compressed concrete elements with various types of non-metallic fiber and rods reinforcement under static loading

NASA Astrophysics Data System (ADS)

Nevskii, A. V.; Baldin, I. V.; Kudyakov, K. L.

2015-01-01

Adoption of modern building materials based on non-metallic fibers and their application in concrete structures represent one of the important issues in construction industry. This paper presents results of investigation of several types of raw materials selected: basalt fiber, carbon fiber and composite fiber rods based on glass and carbon. Preliminary testing has shown the possibility of raw materials to be effectively used in compressed concrete elements. Experimental program to define strength and deformability of compressed concrete elements with non-metallic fiber reinforcement and rod composite reinforcement included design, manufacture and testing of several types of concrete samples with different types of fiber and longitudinal rod reinforcement. The samples were tested under compressive static load. The results demonstrated that fiber reinforcement of concrete allows increasing carrying capacity of compressed concrete elements and reducing their deformability. Using composite longitudinal reinforcement instead of steel longitudinal reinforcement in compressed concrete elements insignificantly influences bearing capacity. Combined use of composite rod reinforcement and fiber reinforcement in compressed concrete elements enables to achieve maximum strength and minimum deformability.

GROWING ALTERNATIVE SUSTAINABLE BUILDINGS: BIO-COMPOSITE PRODUCTS FROM NATURAL FIBER, BIODEGRADABLE AND RECYCLABLE POLYMER MATERIALS FOR LOAD-BEARING CONSTRUCTION COMPONENTS

EPA Science Inventory

The project is an integrative educational and research project that will revolutionize design and construction methods towards more sustainable buildings. The project will develop and test new product design concepts using bio-composite materials in load-bearing and fa&cced...

Measurement of vibrations at different sections of rail through fiber optic sensors

NASA Astrophysics Data System (ADS)

Barreda, A.; Molina-Jiménez, T.; Valero, E.; Recuero, S.

2011-09-01

This paper presents the results of an investigation about how the vibration of railway vehicles affects nearby buildings. The overall objective is to study the vibration generated in urban environments by tram, train and subway, its transmission to the ground and how the buildings and constructions of the environment receive them. Vibrations can generate noise and vibrations in buildings. For this reason it is necessary to characterize the level of vibration affecting rail, road infrastructure and sidewalks and nearby buildings, to assess the influence of the train (speed, type, profile wheel ,..), rail (area of rolling) and route of step, and finally define interim corrective measures. In this study measurements of levels of energy and vibration excitation frequencies will be undertaken through optical techniques: optical fiber networks with distributed Bragg sensors. Measuring these vibrations in different configurations allows us to evaluate the suitability of different sections of rail for different types of uses or environments. This study aims to help improve the safety of the built environment in the vicinity of a railway operation, and thus increase the comfort for passengers and to reduce the environmental impact.

Synthetic fibers as microplastics in the marine environment: A review from textile perspective with a focus on domestic washings.

PubMed

Salvador Cesa, Flavia; Turra, Alexander; Baruque-Ramos, Julia

2017-11-15

The ubiquity of plastic materials in the environment has been, for long, a matter of discussion. Smaller particles, named microplastics (<5mm), gained attention more recently and are now the focus of many studies, especially for their particularities regarding sources, characteristics and effects (e.g., surface-area-to-volume ratio which can increase their potential to transport toxic substances). Fibers from textile materials are a subgroup of microplastics and can be originated from domestic washings, as machine filters and wastewater treatment plants (WWTPs) are not specifically designed to retain them. Once in the environment, fibers can reach concentrations up to thousands of particles per cubic meter, being available to be ingested by a broad range of species. In this scenario, this review adds and details the textile perspective to the microplastics exploring nomenclature, characteristics and factors influencing emission, but also evidencing gaps in knowledge needed to overcome this issue. Preliminarily, general information about marine litter and plastics, followed by specific aspects regarding textile fibers as microplastics, were introduced. Then fiber sources to microplastic pollution were discussed, mainly focusing on domestic washings that pass through WWTPs. Studies that reveal domestic washing as microplastic sources are scarce and there is a considerable lack of standardization in methods as well as incorporation of textile aspects in experimental design. Knowledge gaps include laundry parameters (e.g., water temperature, use of chemicals) and textile articles characteristics (e.g., yarn type, fabric structure) orchestrated by consumers' choice. The lack of information on the coverage and efficiency of sewage treatment systems to remove textile fibers also prevent a global understanding of such sources. The search of alternatives and applicable solutions should come from an integrated, synergic and global perspective, of both environmental and textile area, which still need to be fostered. Copyright © 2017 Elsevier B.V. All rights reserved.

A High-Resolution Endoscope of Small Diameter Using Electromagnetically Vibration of Single Fiber

NASA Astrophysics Data System (ADS)

Matsunaga, Tadao; Hino, Ryunosuke; Makishi, Wataru; Esashi, Masayoshi; Haga, Yoichi

For high resolution visual inspection in the narrow space of the human body, small diameter endoscope has been developed which utilize electromagnetically vibration of single fiber. Thin endoscopes are effective for inspection in the narrow space of the human body, for example, in the blood vessel, lactiferous duct for detection infiltration of breast cancer, and periodontal gap between gingiva and tooth. This endoscope consists of single optical fiber and photofabricated driving coils. A collimator lens and a cylindrical permanent magnet are fixed on the optical fiber, and the tilted driving coils have been patterned on a 1.08 mm outer diameter thin tube. The fiber is positioned at the center of the tube which is patterned the coils. When an electrical alternating current at the resonance frequency is supplied to the coils, the permanent magnet which is fixed to the fiber is vibrated electromagnetically and scanned one or two dimensionally. This paper reports small diameter endoscope by using electromagnetically vibration of single fiber. Optical coherence tomography imaging has also been carried out with the fabricated endoscope and cross-section image of sub-surface skin of thumb was observed.

Ultrahigh resolution radiation imaging system using an optical fiber structure scintillator plate.

PubMed

Yamamoto, Seiichi; Kamada, Kei; Yoshikawa, Akira

2018-02-16

High resolution imaging of radiation is required for such radioisotope distribution measurements as alpha particle detection in nuclear facilities or high energy physics experiments. For this purpose, we developed an ultrahigh resolution radiation imaging system using an optical fiber structure scintillator plate. We used a ~1-μm diameter fiber structured GdAlO 3 :Ce (GAP) /α-Al 2 O 3 scintillator plate to reduce the light spread. The fiber structured scintillator plate was optically coupled to a tapered optical fiber plate to magnify the image and combined with a lens-based high sensitivity CCD camera. We observed the images of alpha particles with a spatial resolution of ~25 μm. For the beta particles, the images had various shapes, and the trajectories of the electrons were clearly observed in the images. For the gamma photons, the images also had various shapes, and the trajectories of the secondary electrons were observed in some of the images. These results show that combining an optical fiber structure scintillator plate with a tapered optical fiber plate and a high sensitivity CCD camera achieved ultrahigh resolution and is a promising method to observe the images of the interactions of radiation in a scintillator.

Inscription of first order fiber Bragg gratings in sapphire fibers by 400 nm femtosecond laser pulses

NASA Astrophysics Data System (ADS)

Elsmann, Tino; Habisreuther, Tobias; Graf, Albrecht; Rothhardt, Manfred; Bartelt, Hartmut

2013-05-01

We demonstrate the inscription of fiber Bragg gratings in single crystalline sapphire using the second harmonic of a Ti:Sa-amplified femtosecond laser system. With the laser wavelength of 400 nm first order gratings were fabricated. The interferometric inscription was performed out using the Talbot interferometer. This way, not only single gratings but also multiplexed sensor arrays were realized. For evaluating of the sensor signals an adapted multimodal interrogation setup was build up, because the sapphire fiber is an extreme multimodal air clad fiber. Due to the multimodal reflection spectrum, different peak functions have been tested to evaluate the thermal properties of the grating. The temperature sensors were tested for high temperature applications up to 1200°C with a thermal sensitivity in the order of 25 pm/K which is more than the doubled of that one reached with Bragg gratings in conventional silica fibers.

Review the role of terminal domains during storage and assembly of spider silk proteins.

PubMed

Eisoldt, Lukas; Thamm, Christopher; Scheibel, Thomas

2012-06-01

Fibrous proteins in nature fulfill a wide variety of functions in different structures ranging from cellular scaffolds to very resilient structures like tendons and even extra-corporal fibers such as silks in spider webs or silkworm cocoons. Despite their different origins and sequence varieties many of these fibrous proteins share a common building principle: they consist of a large repetitive core domain flanked by relatively small non-repetitive terminal domains. Amongst protein fibers, spider dragline silk shows prominent mechanical properties that exceed those of man-made fibers like Kevlar. Spider silk fibers assemble in a spinning process allowing the transformation from an aqueous solution into a solid fiber within milliseconds. Here, we highlight the role of the non-repetitive terminal domains of spider dragline silk proteins during storage in the gland and initiation of the fiber assembly process. Copyright © 2011 Wiley Periodicals, Inc.

White matter pathways for prosodic structure building: A case study.

PubMed

Sammler, Daniela; Cunitz, Katrin; Gierhan, Sarah M E; Anwander, Alfred; Adermann, Jens; Meixensberger, Jürgen; Friederici, Angela D

2018-05-11

The relevance of left dorsal and ventral fiber pathways for syntactic and semantic comprehension is well established, while pathways for prosody are little explored. The present study examined linguistic prosodic structure building in a patient whose right arcuate/superior longitudinal fascicles and posterior corpus callosum were transiently compromised by a vasogenic peritumoral edema. Compared to ten matched healthy controls, the patient's ability to detect irregular prosodic structure significantly improved between pre- and post-surgical assessment. This recovery was accompanied by an increase in average fractional anisotropy (FA) in right dorsal and posterior transcallosal fiber tracts. Neither general cognitive abilities nor (non-prosodic) syntactic comprehension nor FA in right ventral and left dorsal fiber tracts showed a similar pre-post increase. Together, these findings suggest a contribution of right dorsal and inter-hemispheric pathways to prosody perception, including the right-dorsal tracking and structuring of prosodic pitch contours that is transcallosally informed by concurrent syntactic information. Copyright © 2018 Elsevier Inc. All rights reserved.

High-Temperature Insulating Gap Filler

NASA Technical Reports Server (NTRS)

Toombs, Gordon R.; Oyoung, Kevin K.; Stevens, Everett G.

1991-01-01

New inorganic, ceramic filler for gaps between refractory ceramic tiles offers high resistance to heat and erosion. Consists of ceramic-fiber fabric precoated with silica and further coated with silica containing small amount of silicon carbide powder to increase thermal emittance. Developed as replacement for organic filler used on thermal-protection system of Space Shuttle. Promises to serve for many missions and to reduce cost and delay of refurbishing aerospace craft. Used as sealing material in furnaces or as heat shield for sensitive components in automobiles, aircraft, and home appliances.

Long-term survival of endodontically treated, maxillary anterior teeth restored with either tapered or parallel-sided glass-fiber posts and full-ceramic crown coverage.

PubMed

Signore, Antonio; Benedicenti, Stefano; Kaitsas, Vassilios; Barone, Michele; Angiero, Francesca; Ravera, Giambattista

2009-02-01

This retrospective study investigated the clinical effectiveness over up to 8 years of parallel-sided and of tapered glass-fiber posts, in combination with either hybrid composite or dual-cure composite resin core material, in endodontically treated, maxillary anterior teeth covered with full-ceramic crowns. The study population comprised 192 patients and 526 endodontically treated teeth, with various degrees of hard-tissue loss, restored by the post-and-core technique. Four groups were defined based on post shape and core build-up materials, and within each group post-and-core restorations were assigned randomly with respect to root morphology. Inclusion criteria were symptom-free endodontic therapy, root-canal treatment with a minimum apical seal of 4mm, application of rubber dam, need for post-and-core complex because of coronal tooth loss, and tooth with at least one residual coronal wall. Survival rate of the post-and-core restorations was determined using Kaplan-Meier statistical analysis. The restorations were examined clinically and radiologically; mean observation period was 5.3 years. The overall survival rate of glass-fiber post-and-core restorations was 98.5%. The survival rate for parallel-sided posts was 98.6% and for tapered posts was 96.8%. Survival rates for core build-up materials were 100% for dual-cure composite and 96.8% for hybrid light-cure composite. For both glass-fiber post designs and for both core build-up materials, clinical performance was satisfactory. Survival was higher for teeth retaining four and three coronal walls.

Fiber optic gap gauge

DOEpatents

Wood, Billy E [Livermore, CA; Groves, Scott E [Brentwood, CA; Larsen, Greg J [Brentwood, CA; Sanchez, Roberto J [Pleasanton, CA

2006-11-14

A lightweight, small size, high sensitivity gauge for indirectly measuring displacement or absolute gap width by measuring axial strain in an orthogonal direction to the displacement/gap width. The gap gauge includes a preferably titanium base having a central tension bar with springs connecting opposite ends of the tension bar to a pair of end connector bars, and an elongated bow spring connected to the end connector bars with a middle section bowed away from the base to define a gap. The bow spring is capable of producing an axial strain in the base proportional to a displacement of the middle section in a direction orthogonal to the base. And a strain sensor, such as a Fabry-Perot interferometer strain sensor, is connected to measure the axial strain in the base, so that the displacement of the middle section may be indirectly determined from the measurement of the axial strain in the base.

Optimization Of Shear Modes To Produce Enhanced Bandwidth In Ghz GaP Bragg Cells

NASA Astrophysics Data System (ADS)

Soos, J., I.; Rosemeier, R. G.; Rosenbaum, J.

1988-02-01

Applications of Gallium Phosphide (GaP) acousto-optic devices, at wavelengths from 570nm - 1.06um seem to be ideal for fiber optic modulators, scanners, deflectors, frequency shifters, Q-switches and mode lockers. One of the major applications are for RF spectrometers in early warning radar receivers and auto-correlators. Longitudinal GaP acousto-optic Bragg cells which have respectively operational frequencies in the range of 200 MHz - 3 GHz and diffraction efficiencies in the range of 120%/RF watt to 1%/RF watt have recently been fabricated. Comparatively, shear GaP devices which have operational frequencies in the range of 200 MHz to 2 GHz and diffraction efficiencies from 80%/RF watt to 7%/RF watt have also been constructed.

Fabrication of 3-D Photonic Band Gap Crystals Via Colloidal Self-Assembly

NASA Technical Reports Server (NTRS)

Subramaniam, Girija; Blank, Shannon

2005-01-01

The behavior of photons in a Photonic Crystals, PCs, is like that of electrons in a semiconductor in that, it prohibits light propagation over a band of frequencies, called Photonic Band Gap, PBG. Photons cannot exist in these band gaps like the forbidden bands of electrons. Thus, PCs lend themselves as potential candidates for devices based on the gap phenomenon. The popular research on PCs stem from their ability to confine light with minimal losses. Large scale 3-D PCs with a PBG in the visible or near infra red region will make optical transistors and sharp bent optical fibers. Efforts are directed to use PCs for information processing and it is not long before we can have optical integrated circuits in the place of electronic ones.

Motivational Gaps and Perceptual Bias of Initial Motivation Additional Indicators of Quality for e-Learning Courses

ERIC Educational Resources Information Center

Cação, Rosário

2017-01-01

We describe a study on the motivation of trainees in e-learning-based professional training and on the effect of their motivation upon the perceptions they build about the quality of the courses. We propose the concepts of "perceived motivational gap" and "real motivational gap" as indicators of e-learning quality, which…

Wind tunnel measurements of three-dimensional wakes of buildings. [for aircraft safety applications

NASA Technical Reports Server (NTRS)

Logan, E., Jr.; Lin, S. H.

1982-01-01

Measurements relevant to the effect of buildings on the low level atmospheric boundary layer are presented. A wind tunnel experiment was undertaken to determine the nature of the flow downstream from a gap between two transversely aligned, equal sized models of rectangular cross section. These building models were immersed in an equilibrium turbulent boundary layer which was developed on a smooth floor in a zero longitudinal pressure gradient. Measurements with an inclined (45 degree) hot-wire were made at key positions downstream of models arranged with a large, small, and no gap between them. Hot-wire theory is presented which enables computation of the three mean velocity components, U, V and W, as well as Reynolds stresses. These measurements permit understanding of the character of the wake downstream of laterally spaced buildings. Surface streamline patterns obtained by the oil film method were used to delineate the separation region to the rear of the buildings for a variety of spacings.

The role of rapid solidification processing in the fabrication of fiber reinforced metal matrix composites

NASA Technical Reports Server (NTRS)

Locci, Ivan E.; Noebe, Ronald D.

1989-01-01

Advanced composite processing techniques for fiber reinforced metal matrix composites require the flexibility to meet several widespread objectives. The development of uniquely desired matrix microstructures and uniformly arrayed fiber spacing with sufficient bonding between fiber and matrix to transmit load between them without degradation to the fiber or matrix are the minimum requirements necessary of any fabrication process. For most applications these criteria can be met by fabricating composite monotapes which are then consolidated into composite panels or more complicated components such as fiber reinforced turbine blades. Regardless of the end component, composite monotapes are the building blocks from which near net shape composite structures can be formed. The most common methods for forming composite monotapes are the powder cloth, foil/fiber, plasma spray, and arc spray processes. These practices, however, employ rapid solidification techniques in processing of the composite matrix phase. Consequently, rapid solidification processes play a vital and yet generally overlooked role in composite fabrication. The future potential of rapid solidification processing is discussed.

Photonic crystal fiber sensing characteristics research based on alcohol asymmetry filling

NASA Astrophysics Data System (ADS)

Shi, Fu-quan; Luo, Yan; Li, Hai-tao; Peng, Bao-jin

2018-02-01

A new type of Sagnac fiber temperature sensor based on alcohol asymmetric filling photonic crystal fiber is proposed. First, the corrosion of photonic crystal fiber and the treatment of air hole collapse are carried out. Then, the asymmetric structure of photonic crystal fiber is filled with alcohol, and then the structure is connected to the Sagnac interference ring. When the temperature changes, the thermal expansion effect of filling alcohol will lead to the change of birefringence of photonic crystal fiber, so that the interference spectrum of the sensor will drift along with the change of temperature. The experimental results show that the interference red shift will occur with the increase of temperature, and the temperature sensitivity is 0.1864nm/ °C. The sensor has high sensitivity to temperature. At the same time, the structure has the advantages of high stability, anti electromagnetic interference and easy to build. It provides a new method for obtaining birefringence in ordinary photonic crystal fibers.

IEA EBC Annex 66: Definition and simulation of occupant behavior in buildings

DOE PAGES

Yan, Da; Hong, Tianzhen; Dong, Bing; ...

2017-09-28

Here, more than 30% of the total primary energy in the world is consumed in buildings. It is crucial to reduce building energy consumption in order to preserve energy resources and mitigate global climate change. Building performance simulations have been widely used for the estimation and optimization of building performance, providing reference values for the assessment of building energy consumption and the effects of energy-saving technologies. Among the various factors influencing building energy consumption, occupant behavior has drawn increasing attention. Occupant behavior includes occupant presence, movement, and interaction with building energy devices and systems. However, there are gaps in occupantmore » behavior modeling as different energy modelers have employed varied data and tools to simulate occupant behavior, therefore producing different and incomparable results. Aiming to address these gaps, the International Energy Agency (IEA) Energy in Buildings and Community (EBC) Programme Annex 66 has established a scientific methodological framework for occupant behavior research, including data collection, behavior model representation, modeling and evaluation approaches, and the integration of behavior modeling tools with building performance simulation programs. Annex 66 also includes case studies and application guidelines to assist in building design, operation, and policymaking, using interdisciplinary approaches to reduce energy use in buildings and improve occupant comfort and productivity. This paper highlights the key research issues, methods, and outcomes pertaining to Annex 66, and offers perspectives on future research needs to integrate occupant behavior with the building life cycle.« less

IEA EBC Annex 66: Definition and simulation of occupant behavior in buildings

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

Yan, Da; Hong, Tianzhen; Dong, Bing

Here, more than 30% of the total primary energy in the world is consumed in buildings. It is crucial to reduce building energy consumption in order to preserve energy resources and mitigate global climate change. Building performance simulations have been widely used for the estimation and optimization of building performance, providing reference values for the assessment of building energy consumption and the effects of energy-saving technologies. Among the various factors influencing building energy consumption, occupant behavior has drawn increasing attention. Occupant behavior includes occupant presence, movement, and interaction with building energy devices and systems. However, there are gaps in occupantmore » behavior modeling as different energy modelers have employed varied data and tools to simulate occupant behavior, therefore producing different and incomparable results. Aiming to address these gaps, the International Energy Agency (IEA) Energy in Buildings and Community (EBC) Programme Annex 66 has established a scientific methodological framework for occupant behavior research, including data collection, behavior model representation, modeling and evaluation approaches, and the integration of behavior modeling tools with building performance simulation programs. Annex 66 also includes case studies and application guidelines to assist in building design, operation, and policymaking, using interdisciplinary approaches to reduce energy use in buildings and improve occupant comfort and productivity. This paper highlights the key research issues, methods, and outcomes pertaining to Annex 66, and offers perspectives on future research needs to integrate occupant behavior with the building life cycle.« less

Subsidence monitoring system for offshore applications: technology scouting and feasibility studies

NASA Astrophysics Data System (ADS)

Miandro, R.; Dacome, C.; Mosconi, A.; Roncari, G.

2015-11-01

Because of concern about possible impacts of hydrocarbon production activities on coastal-area environments and infrastructures, new hydrocarbon offshore development projects in Italy must submit a monitoring plan to Italian authorities to measure and analyse real-time subsidence evolution. The general geological context, where the main offshore Adriatic fields are located, is represented by young unconsolidated terrigenous sediments. In such geological environments, sea floor subsidence, caused by hydrocarbon extraction, is quite probable. Though many tools are available for subsidence monitoring onshore, few are available for offshore monitoring. To fill the gap ENI (Ente Nazionale Idrocarburi) started a research program, principally in collaboration with three companies, to generate a monitoring system tool to measure seafloor subsidence. The tool, according to ENI design technical-specification, would be a robust long pipeline or cable, with a variable or constant outside diameter (less than or equal to 100 mm) and interval spaced measuring points. The design specifications for the first prototype were: to detect 1 mm altitude variation, to work up to 100 m water depth and investigation length of 3 km. Advanced feasibility studies have been carried out with: Fugro Geoservices B.V. (Netherlands), D'Appolonia (Italy), Agisco (Italy). Five design (using three fundamental measurements concepts and five measurement tools) were explored: cable shape changes measured by cable strain using fiber optics (Fugro); cable inclination measured using tiltmeters (D'Appolonia) and measured using fiber optics (Fugro); and internal cable altitude-dependent pressure changes measured using fiber optics (Fugro) and measured using pressure transducers at discrete intervals along the hydraulic system (Agisco). Each design tool was analysed and a rank ordering of preferences was performed. The third method (measurement of pressure changes), with the solution proposed by Agisco, was deemed most feasible. Agisco is building the first prototype of the tool to be installed in an offshore field in the next few years. This paper describes design of instruments from the three companies to satisfy the design specification.

Reciprocal Modulation of IK1–INa Extends Excitability in Cardiac Ventricular Cells

PubMed Central

Varghese, Anthony

2016-01-01

The inwardly rectifying potassium current (IK1) and the fast inward sodium current (INa) are reciprocally modulated in mammalian ventricular myocytes. An increase in the expression of channels responsible for one of these two currents results in a corresponding increase in expression of the other. These currents are critical in the propagation of action potentials (AP) during the normal functioning of the heart. This study identifies a physiological role for IK1–INa reciprocal modulation in ventricular fiber activation thresholds and conduction. Simulations of action potentials in single cells and propagating APs in cardiac fibers were carried out using an existing model of electrical activity in cardiac ventricular myocytes. The conductances, GK1, of the inwardly rectifying potassium current, and GNa, of the fast inward sodium current were modified independently and in tandem to simulate reciprocal modulation. In single cells, independent modulation of GK1 alone resulted in changes in activation thresholds that were qualitatively similar to those for reciprocal GK1–GNa modulation and unlike those due to independent modulation of GNa alone, indicating that GK1 determines the cellular activation threshold. On the other hand, the variations in conduction velocity in cardiac cell fibers were similar for independent GNa modulation and for tandem changes in GK1–GNa, suggesting that GNa is primarily responsible for setting tissue AP conduction velocity. Conduction velocity dependence on GK1–GNa is significantly affected by the intercellular gap junction conductance. While the effects on the passive fiber space constant due to changes in both GK1 and the intercellular gap junction conductance, Ggj, were in line with linear cable theory predictions, both conductances had surprisingly large effects on fiber activation thresholds. Independent modulation of GK1 rendered cardiac fibers inexcitable at higher levels of GK1 whereas tandem GK1–GNa changes allowed fibers to remain excitable at high GK1 values. Reciprocal modulation of the inwardly rectifying potassium current and the fast inward sodium current may have a functional role in allowing cardiac tissue to remain excitable when IK1 is upregulated. PMID:27895596

Characterization and modeling of tensile behavior of ceramic woven fabric composites

NASA Technical Reports Server (NTRS)

Kuo, Wen-Shyong; Chen, Wennei Y.; Parvizi-Majidi, Azar; Chou, Tsu-Wei

1991-01-01

This paper examines the tensile behavior of SiC/SiC fabric composites. In the characterization effort, the stress-strain relation and damage evolution are studied with a series of loading and unloading tensile test experiments. The stress-strain relation is linear in response to the initial loading and becomes nonlinear when loading exceeds the proportional limit. Transverse cracking has been observed to be a dominant damage mode governing the nonlinear deformation. The damage is initiated at the inter-tow pores where fiber yarns cross over each other. In the modeling work, the analysis is based upon a fiber bundle model, in which fiber undulation in the warp and fill directions and gaps among fiber yarns have been taken into account. Two limiting cases of fabric stacking arrangements are studied. Closed form solutions are obtained for the composite stiffness and Poisson's ratio. Transverse cracking in the composite is discussed by applying a constant failure strain criterion.

Optical microresonator for application to an opto-electronic oscillator

NASA Astrophysics Data System (ADS)

Wu, Yu-Mei; Vivien, Laurent; Cassan, Eric; Luong, Vu Hai Nam; Nguyen, Lam Duy; Journet, Bernard

2010-02-01

Optoelectronic oscillators are classically based on a feedback fiber loop acting as a delay line for high spectral purity. One of the problems due to long fiber loops is the size and the requirement of temperature control. Going toward integrated solutions requires the introduction of optical resonators with a very high quality factor. A structure based on silicon on insulator material has been designed for application to an oscillator working at 8 GHz. The micro-resonator has a stadium shape with a ridge of 30 nm height, 1 μm width, a millimetric radius and a gap of some microns in agreement with the required free spectral range. A quality factor of 500000 can be achieved leading to an equivalent fiber loop of 2 km.

Adaptive Crack Modeling with Interface Solid Elements for Plain and Fiber Reinforced Concrete Structures.

PubMed

Zhan, Yijian; Meschke, Günther

2017-07-08

The effective analysis of the nonlinear behavior of cement-based engineering structures not only demands physically-reliable models, but also computationally-efficient algorithms. Based on a continuum interface element formulation that is suitable to capture complex cracking phenomena in concrete materials and structures, an adaptive mesh processing technique is proposed for computational simulations of plain and fiber-reinforced concrete structures to progressively disintegrate the initial finite element mesh and to add degenerated solid elements into the interfacial gaps. In comparison with the implementation where the entire mesh is processed prior to the computation, the proposed adaptive cracking model allows simulating the failure behavior of plain and fiber-reinforced concrete structures with remarkably reduced computational expense.

Adaptive Crack Modeling with Interface Solid Elements for Plain and Fiber Reinforced Concrete Structures

PubMed Central

Zhan, Yijian

2017-01-01

The effective analysis of the nonlinear behavior of cement-based engineering structures not only demands physically-reliable models, but also computationally-efficient algorithms. Based on a continuum interface element formulation that is suitable to capture complex cracking phenomena in concrete materials and structures, an adaptive mesh processing technique is proposed for computational simulations of plain and fiber-reinforced concrete structures to progressively disintegrate the initial finite element mesh and to add degenerated solid elements into the interfacial gaps. In comparison with the implementation where the entire mesh is processed prior to the computation, the proposed adaptive cracking model allows simulating the failure behavior of plain and fiber-reinforced concrete structures with remarkably reduced computational expense. PMID:28773130

Plug and Process Loads Capacity and Power Requirements Analysis

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

Sheppy, M.; Gentile-Polese, L.

2014-09-01

This report addresses gaps in actionable knowledge that would help reduce the plug load capacities designed into buildings. Prospective building occupants and real estate brokers lack accurate references for plug and process load (PPL) capacity requirements, so they often request 5-10 W/ft2 in their lease agreements. Limited initial data, however, suggest that actual PPL densities in leased buildings are substantially lower. Overestimating PPL capacity leads designers to oversize electrical infrastructure and cooling systems. Better guidance will enable improved sizing and design of these systems, decrease upfront capital costs, and allow systems to operate more energy efficiently. The main focus ofmore » this report is to provide industry with reliable, objective third-party guidance to address the information gap in typical PPL densities for commercial building tenants. This could drive changes in negotiations about PPL energy demands.« less

Capacity Building and Financing Oral Health in the African and Middle East Region.

PubMed

Mumghamba, E G; Joury, E; Fatusi, O; Ober-Oluoch, J; Onigbanjo, R J; Honkala, S

2015-07-01

Many low- and middle-income countries do not yet have policies to implement effective oral health programs. A reason is lack of human and financial resources. Gaps between resource needs and available health funding are widening. By building capacity, countries aim to improve oral health through actions by oral health care personnel and oral health care organizations and their communities. Capacity building involves achieving measurable and sustainable results in training, research, and provision of care. Actions include advancement of knowledge, attitudes and skills, expansion of support, and development of cohesiveness and partnerships. The aim of this critical review is to review existing knowledge and identify gaps and variations between and within different income levels in relation to the capacity building and financing oral health in the African and Middle East region (AMER). A second aim is to formulate research priorities and outline a research agenda for capacity building and financing to improve oral health and reduce oral health inequalities in the AMER. The article focuses on capacity building for oral health and oral health financing in the AMER of the IADR. In many communities in the AMER, there are clear and widening gaps between the dental needs and the existing capacity to meet these needs in terms of financial and human resources. Concerted efforts are required to improve access to oral health care through appropriate financing mechanisms, innovative health insurance schemes, and donor support and move toward universal oral health care coverage to reduce social inequality in the region. It is necessary to build capacity and incentivize the workforce to render evidence-based services as well as accessing funds to conduct research on equity and social determinants of oral health while promoting community engagement and a multidisciplinary approach. © International & American Associations for Dental Research 2015.

Textural analyses of carbon fiber materials by 2D-FFT of complex images obtained by high frequency eddy current imaging (HF-ECI)

NASA Astrophysics Data System (ADS)

Schulze, Martin H.; Heuer, Henning

2012-04-01

Carbon fiber based materials are used in many lightweight applications in aeronautical, automotive, machine and civil engineering application. By the increasing automation in the production process of CFRP laminates a manual optical inspection of each resin transfer molding (RTM) layer is not practicable. Due to the limitation to surface inspection, the quality parameters of multilayer 3 dimensional materials cannot be observed by optical systems. The Imaging Eddy- Current (EC) NDT is the only suitable inspection method for non-resin materials in the textile state that allows an inspection of surface and hidden layers in parallel. The HF-ECI method has the capability to measure layer displacements (misaligned angle orientations) and gap sizes in a multilayer carbon fiber structure. EC technique uses the variation of the electrical conductivity of carbon based materials to obtain material properties. Beside the determination of textural parameters like layer orientation and gap sizes between rovings, the detection of foreign polymer particles, fuzzy balls or visualization of undulations can be done by the method. For all of these typical parameters an imaging classification process chain based on a high resolving directional ECimaging device named EddyCus® MPECS and a 2D-FFT with adapted preprocessing algorithms are developed.

Non-proximity resonant tunneling in multi-core photonic band gap fibers: An efficient mechanism for engineering highly-selective ultra-narrow band pass splitters

NASA Astrophysics Data System (ADS)

Florous, Nikolaos J.; Saitoh, Kunimasa; Murao, Tadashi; Koshiba, Masanori; Skorobogatiy, Maksim

2006-05-01

The objective of the present investigation is to demonstrate the possibility of designing compact ultra-narrow band-pass filters based on the phenomenon of non-proximity resonant tunneling in multi-core photonic band gap fibers (PBGFs). The proposed PBGF consists of three identical air-cores separated by two defected air-holes which act as highly-selective resonators. With a fine adjustment of the design parameters associated with the resonant-air-holes, phase matching at two distinct wavelengths can be achieved, thus enabling very narrow-band resonant directional coupling between the input and the two output cores. The validation of the proposed design is ensured with an accurate PBGF analysis based on finite element modal and beam propagation algorithms. Typical characteristics of the proposed device over a single polarization are: reasonable short coupling length of 2.7 mm, dual bandpass transmission response at wavelengths of 1.339 and 1.357 μm, with corresponding full width at half maximum bandwidths of 1.2 nm and 1.1 nm respectively, and a relatively high transmission of 95% at the exact resonance wavelengths. The proposed ultra-narrow band-pass filter can be employed in various applications such as all-fiber bandpass/bandstop filtering and resonant sensors.

Using Finite Element and Eigenmode Expansion Methods to Investigate the Periodic and Spectral Characteristic of Superstructure Fiber Bragg Gratings

PubMed Central

He, Yue-Jing; Hung, Wei-Chih; Lai, Zhe-Ping

2016-01-01

In this study, a numerical simulation method was employed to investigate and analyze superstructure fiber Bragg gratings (SFBGs) with five duty cycles (50%, 33.33%, 14.28%, 12.5%, and 10%). This study focuses on demonstrating the relevance between design period and spectral characteristics of SFBGs (in the form of graphics) for SFBGs of all duty cycles. Compared with complicated and hard-to-learn conventional coupled-mode theory, the result of the present study may assist beginner and expert designers in understanding the basic application aspects, optical characteristics, and design techniques of SFBGs, thereby indirectly lowering the physical concepts and mathematical skills required for entering the design field. To effectively improve the accuracy of overall computational performance and numerical calculations and to shorten the gap between simulation results and actual production, this study integrated a perfectly matched layer (PML), perfectly reflecting boundary (PRB), object meshing method (OMM), and boundary meshing method (BMM) into the finite element method (FEM) and eigenmode expansion method (EEM). The integrated method enables designers to easily and flexibly design optical fiber communication systems that conform to the specific spectral characteristic by using the simulation data in this paper, which includes bandwidth, number of channels, and band gap size. PMID:26861322

Non-proximity resonant tunneling in multi-core photonic band gap fibers: An efficient mechanism for engineering highly-selective ultra-narrow band pass splitters.

PubMed

Florous, Nikolaos J; Saitoh, Kunimasa; Murao, Tadashi; Koshiba, Masanori; Skorobogatiy, Maksim

2006-05-29

The objective of the present investigation is to demonstrate the possibility of designing compact ultra-narrow band-pass filters based on the phenomenon of non-proximity resonant tunneling in multi-core photonic band gap fibers (PBGFs). The proposed PBGF consists of three identical air-cores separated by two defected air-holes which act as highly-selective resonators. With a fine adjustment of the design parameters associated with the resonant-air-holes, phase matching at two distinct wavelengths can be achieved, thus enabling very narrow-band resonant directional coupling between the input and the two output cores. The validation of the proposed design is ensured with an accurate PBGF analysis based on finite element modal and beam propagation algorithms. Typical characteristics of the proposed device over a single polarization are: reasonable short coupling length of 2.7 mm, dual bandpass transmission response at wavelengths of 1.339 and 1.357 mum, with corresponding full width at half maximum bandwidths of 1.2 nm and 1.1 nm respectively, and a relatively high transmission of 95% at the exact resonance wavelengths. The proposed ultra-narrow band-pass filter can be employed in various applications such as all-fiber bandpass/bandstop filtering and resonant sensors.

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.

Ten-year monitoring of high-rise building columns using long-gauge fiber optic sensors

NASA Astrophysics Data System (ADS)

Glisic, B.; Inaudi, D.; Lau, J. M.; Fong, C. C.

2013-05-01

A large-scale lifetime building monitoring program was implemented in Singapore in 2001. The monitoring aims of this unique program were to increase safety, verify performance, control quality, increase knowledge, optimize maintenance costs, and evaluate the condition of the structures after a hazardous event. The first instrumented building, which has now been monitored for more than ten years, is presented in this paper. The long-gauge fiber optic strain sensors were embedded in fresh concrete of ground-level columns, thus the monitoring started at the birth of both the construction material and the structure. Measurement sessions were performed during construction, upon completion of each new story and the roof, and after the construction, i.e., in-service. Based on results it was possible to follow and evaluate long-term behavior of the building through every stage of its life. The results of monitoring were analyzed at a local (column) and global (building) level. Over-dimensioning of one column was identified. Differential settlement of foundations was detected, localized, and its magnitude estimated. Post-tremor analysis was performed. Real long-term behavior of concrete columns was assessed. Finally, the long-term performance of the monitoring system was evaluated. The researched monitoring method, monitoring system, rich results gathered over approximately ten years, data analysis algorithms, and the conclusions on the structural behavior and health condition of the building based on monitoring are presented in this paper.

Does rat granulation tissue maturation involve gap junction communications?

PubMed

Au, Katherine; Ehrlich, H Paul

2007-07-01

Wound healing, a coordinated process, proceeds by sequential changes in cell differentiation and terminates with the deposition of a new connective tissue matrix, a scar. Initially, there is the migratory fibroblast, followed by the proliferative fibroblast, then the synthetic fibroblast, which transforms into the myofibroblast, and finally the apoptotic fibroblast. Gap junction intercellular communications are proposed to coordinate the stringent control of fibroblast phenotypic changes. Does added oleamide, a natural fatty acid that blocks gap junction intercellular communications, alter the phenotypic progression of wound fibroblasts? Pairs of polyvinyl alcohol sponges attached to Alzet pumps, which constantly pumped either oleamide or vehicle solvent, were implanted subcutaneously into three rats. On day 8, implants were harvested and evaluated histologically and biochemically. The capsule of oleamide-treated sponge contained closely packed fibroblasts with little connective tissue between them. The birefringence intensity of that connective tissue was reduced, indicating a reduced density of collagen fiber bundles. Myofibroblasts, identified immunohistologically by alpha-smooth muscle actin-stained stress fibers, were reduced in oleamide-treated implants. Western blot analysis showing less alpha-smooth muscle actin confirmed the reduced density of myofibroblasts. It appears that oleamide retards the progression of wound repair, where less connective tissue is deposited, the collagen is less organized, and the appearance of myofibroblasts is impaired. These findings support the hypothesis that gap junction intercellular communications between wound fibroblasts in granulation tissue play a role in the progression of repair and the maturation of granulation tissue into scar.

Fixed Access Network Sharing

NASA Astrophysics Data System (ADS)

Cornaglia, Bruno; Young, Gavin; Marchetta, Antonio

2015-12-01

Fixed broadband network deployments are moving inexorably to the use of Next Generation Access (NGA) technologies and architectures. These NGA deployments involve building fiber infrastructure increasingly closer to the customer in order to increase the proportion of fiber on the customer's access connection (Fibre-To-The-Home/Building/Door/Cabinet… i.e. FTTx). This increases the speed of services that can be sold and will be increasingly required to meet the demands of new generations of video services as we evolve from HDTV to "Ultra-HD TV" with 4k and 8k lines of video resolution. However, building fiber access networks is a costly endeavor. It requires significant capital in order to cover any significant geographic coverage. Hence many companies are forming partnerships and joint-ventures in order to share the NGA network construction costs. One form of such a partnership involves two companies agreeing to each build to cover a certain geographic area and then "cross-selling" NGA products to each other in order to access customers within their partner's footprint (NGA coverage area). This is tantamount to a bi-lateral wholesale partnership. The concept of Fixed Access Network Sharing (FANS) is to address the possibility of sharing infrastructure with a high degree of flexibility for all network operators involved. By providing greater configuration control over the NGA network infrastructure, the service provider has a greater ability to define the network and hence to define their product capabilities at the active layer. This gives the service provider partners greater product development autonomy plus the ability to differentiate from each other at the active network layer.

Excitation of resonances of microspheres on an optical fiber

NASA Astrophysics Data System (ADS)

Serpengüzel, A.; Arnold, S.; Griffel, G.

1995-04-01

Morphology-dependent resonances (MDR's) of solid microspheres are excited by using an optical fiber coupler. The narrowest measured MDR linewidths are limited by the excitation laser linewidth ( < 0.025 nm). Only MDR's, with an on-resonance to off-resonance intensity ratio of 104, contribute to scattering. The intensity of various resonance orders is understood by the localization principle and the recently developed generalized Lorentz-Mie theory. The microsphere fiber system has potential for becoming a building block in dispersive microphotonics. The basic physics underlying our approach may be considered a harbinger for the coupling of active photonic microstructures such as microdisk lasers.

Effect of Soft Tissue Releases on Joint Space Opening in Total Knee Arthroplasty.

PubMed

Burkhart, Timothy A; Perry, Kevin I; Dobbin, Emily; Howard, James; Lanting, Brent

2016-12-01

The purpose of this study was to determine the gap achieved to the medial and lateral compartments following sectioning and release of the relevant soft tissues in preparation for a total knee arthroplasty. A custom-designed knee tensioner allowed the application of forces to the medial and lateral compartments of 12 cadaveric knee specimens. Loads of 100 N and 200 N were applied to each compartment, and the resulting displacement was measured in the following conditions: (1) All soft tissues intact, (2) an arthrotomy, (3) anterior cruciate ligament (ACL) sectioned, (4) posterior cruciate ligament (PCL) sectioned, and (5) release of the anterior aspect of the deep medial collateral ligament (MCL) fibers. Tensions were applied for all conditions from 90° to 0° of knee flexion in 30° increments. No differences were found in medial or lateral displacement after the arthrotomy or releasing the ACL or PCL at either 100 N or 200 N. At the 100 N load application, there was a significant increase in gap width when the anterior portion of the deep MCL was released (7.49 mm) compared to the intact (5.28 mm) and arthrotomy (5.75 mm) conditions. With respect to the 200 N load application, there were statistically significant differences detected between the deep MCL fiber release (11.09 mm) and intact conditions (8.05 mm) and release of the deep MCL and arthrotomy conditions (8.77 mm). The medial parapetellar arthrotomy, ACL and PCL sectioning did not result in medial or lateral displacement changes. The release of the anterior fibers of the deep MCL as part of the surgical exposure increased the medial gap magnitude. Copyright © 2016 Elsevier Inc. All rights reserved.

Activation of protein kinase C and disruption of endothelial monolayer integrity by sodium arsenite-Potential mechanism in the development of atherosclerosis

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

Pereira, Flavia E.; Coffin, J. Douglas; Beall, Howard D.

2007-04-15

Arsenic exposure has been shown to exacerbate atherosclerosis, beginning with activation of the endothelium that lines the vessel wall. Endothelial barrier integrity is maintained by proteins of the adherens junction (AJ) such as vascular endothelial cadherin (VE-cadherin) and {beta}-catenin and their association with the actin cytoskeleton. In the present study, human aortic endothelial cells (HAECs) were exposed to 1, 5 and 10 {mu}M sodium arsenite [As(III)] for 1, 6, 12 and 24 h, and the effects on endothelial barrier integrity were determined. Immunofluorescence studies revealed formation of actin stress fibers and non-uniform VE-cadherin and {beta}-catenin staining at cell-cell junctions thatmore » were concentration- and time-dependent. Intercellular gaps were observed with a measured increase in endothelial permeability. In addition, concentration-dependent increases in tyrosine phosphorylation (PY) of {beta}-catenin and activation of protein kinase C{alpha} (PKC{alpha}) were observed. Inhibition of PKC{alpha} restored VE-cadherin and {beta}-catenin staining at cell-cell junctions and abolished the As(III)-induced formation of actin stress fibers and intercellular gaps. Endothelial permeability and PY of {beta}-catenin were also reduced to basal levels. These results demonstrate that As(III) induces activation of PKC{alpha}, which leads to increased PY of {beta}-catenin downstream of PKC{alpha} activation. Phosphorylation of {beta}-catenin plausibly severs the association of VE-cadherin and {beta}-catenin, which along with formation of actin stress fibers, results in intercellular gap formation and increased endothelial permeability. To the best of our knowledge, this is the first report demonstrating that As(III) causes a loss of endothelial monolayer integrity, which potentially could contribute to the development of atherosclerosis.« less

Asbestos-containing materials and airborne asbestos levels in industrial buildings in Korea.

PubMed

Choi, Sangjun; Suk, Mee-Hee; Paik, Nam Won

2010-03-01

Recently in Korea, the treatment of asbestos-containing materials (ACM) in building has emerged as one of the most important environmental health issues. This study was conducted to identify the distribution and characteristics of ACM and airborne asbestos concentrations in industrial buildings in Korea. A total of 1285 presumed asbestos-containing material (PACM) samples were collected from 80 workplaces across the nation, and 40% of the PACMs contained more than 1% of asbestos. Overall, 94% of the surveyed workplaces contained ACM. The distribution of ACM did not show a significant difference by region, employment size, or industry. The total ACM area in the buildings surveyed was 436,710 m2. Ceiling tile ACM accounted for 61% (267,093 m2) of the total ACM area, followed by roof ACM (32%), surfacing ACM (6.1%), and thermal system insulation (TSI). In terms of asbestos type, 98% of total ACM was chrysotile, while crocidolite was not detected. A comparison of building material types showed that the material with the highest priority for regular management is ceiling tile, followed by roof, TSI, and surfacing material. The average airborne concentration of asbestos sampled without disturbing in-place ACM was 0.0028 fibers/cc by PCM, with all measurements below the standard of recommendation for indoor air quality in Korea (0.01 fibers/cc).

Multi-criteria thermal evaluation of wall enclosures of high-rise buildings insulated products based on modified fibers

NASA Astrophysics Data System (ADS)

Pavlov, Alexey; Pavlova, Larisa; Pavlova, Lyudmila

2018-03-01

In article results of research of versions of offered types of heaters on the basis of products from the modified fibers for designing energy efficient building enclosures residential high-rise buildings are presented. Traditional building materials (reinforced concrete, brick, wood) are not able to provide the required value of thermal resistance in areas with a temperate and harsh Russia climate in a single-layered enclosing structure. It can be achieved in a multi-layered enclosing structure, where the decisive role is played by new insulating materials with high thermal properties. In general, modern design solutions for external walls are based on the use of new effective thermal insulation materials with the use of the latest technology. The relevance of the proposed topic is to research thermoinsulation properties of new mineral heaters. Theoretical researches of offered heaters from mineral wool on slime-colloidal binder, bentocolloid and microdispersed binders are carried out. In addition, theoretical studies were carried out with several types of facade systems. Comprehensive studies were conducted on the resistance to heat transfer, resistance to vapor permeation and air permeability. According to the received data, recommendations on the use of insulation types depending on the number of storeys of buildings are proposed.

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.

Dietary fiber future directions: integrating new definitions and findings to inform nutrition research and communication.

PubMed

Jones, Julie Miller

2013-01-01

The CODEX Alimentarius definition of dietary fiber includes all nondigestible carbohydrate polymers with a degree of polymerization of 3 or more as dietary fiber with the proviso that they show health benefits. The global definition, if accepted by all authoritative bodies, offers a chance for international harmonization in research, food composition tables, and food labeling. Its nonacceptance highlights problems that may develop when definitions vary by region. The definition requires that the research community agrees upon physiological effects for which there is substantial scientific agreement, e.g., fibers' effects on laxation and gut health, on attenuating blood lipids and blood glucose and insulin, and in promoting fermentation in the large bowel. The definition also necessitates the delineation of research protocols to prove the benefits of various isolated and synthesized fibers. These should emanate from evidence-based reviews that fairly weigh epidemiological data while considering that added fibers are not reflected in many food composition databases. They then should include well-controlled, randomized, control trials and utilize animal studies to determine mechanisms. Agreement on many study variables such as the type of subject and the type of baseline diet that best fits the question under investigation will also be needed. Finally, the definition establishes that all types of fiber can address the severe fiber consumption gap that exists throughout the world by recognizing that the combination of fiber-rich and -fortified foods increases fiber intake while allowing consumers to stay within allowed energy levels.

A Mini Review on Nanocarbon-Based 1D Macroscopic Fibers: Assembly Strategies and Mechanical Properties

NASA Astrophysics Data System (ADS)

Kou, Liang; Liu, Yingjun; Zhang, Cheng; Shao, Le; Tian, Zhanyuan; Deng, Zengshe; Gao, Chao

2017-10-01

Nanocarbon-based materials, such as carbon nanotubes (CNTs) and graphene have been attached much attention by scientific and industrial community. As two representative nanocarbon materials, one-dimensional CNTs and two-dimensional graphene both possess remarkable mechanical properties. In the past years, a large amount of work have been done by using CNTs or graphene as building blocks for constructing novel, macroscopic, mechanically strong fibrous materials. In this review, we summarize the assembly approaches of CNT-based fibers and graphene-based fibers in chronological order, respectively. The mechanical performances of these fibrous materials are compared, and the critical influences on the mechanical properties are discussed. Personal perspectives on the fabrication methods of CNT- and graphene-based fibers are further presented.

41. View of electro/mechanical fiber optic system panel in transmitter ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

41. View of electro/mechanical fiber optic system panel in transmitter building no. 102. Images projected to screen (panel at upper left) are projected to back side of screen located in MWOC to display changing information. - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK

Effect of ultraviolet light irradiation period on bond strengths between fiber-reinforced composite post and core build-up composite resin.

PubMed

Asakawa, Yuya; Takahashi, Hidekazu; Iwasaki, Naohiko; Kobayashi, Masahiro

2014-01-01

The aim of the present study was to characterize the effects of the ultraviolet light (UV) irradiation period on the bond strength of fiber-reinforced composite (FRC) posts to core build-up resin. Three types of FRC posts were prepared using polymethyl methacrylate, urethane dimethacrylate, and epoxy resin. The surfaces of these posts were treated using UV irradiation at a distance of 15 mm for 0 to 600 s. The pull-out bond strength was measured and analyzed with the Dunnett's comparison test (α=0.05). The bond strengths of the post surfaces without irradiation were 6.9 to 7.4 MPa; those after irradiation were 4.2 to 26.1 MPa. The bond strengths significantly increased after 15 to 120-s irradiation. UV irradiation on the FRC posts improved the bond strengths between the FRC posts and core build-up resin regardless of the type of matrix resin.

Use of Natural-Fiber Bio-Composites in Construction versus Traditional Solutions: Operational and Embodied Energy Assessment.

PubMed

Galan-Marin, Carmen; Rivera-Gomez, Carlos; Garcia-Martinez, Antonio

2016-06-13

During the last decades natural polymers have become more and more frequent to replace traditional inorganic stabilizers in building materials. The purpose of this research is to establish a comparison between the most conventional building material solutions for load-bearing walls and a type of biomaterial. This comparison will focus on load-bearing walls as used in a widespread type of twentieth century dwelling construction in Europe and still used in developing countries nowadays. To carry out this analysis, the structural and thermal insulation characteristics of different construction solutions are balanced. The tool used for this evaluation is the life cycle assessment throughout the whole lifespan of these buildings. This research aims to examine the environmental performance of each material assessed: fired clay brick masonry walls (BW), concrete block masonry walls (CW), and stabilized soil block masonry walls (SW) stabilized with natural fibers and alginates. These conventional and new materials are evaluated from the point of view of both operational and embodied energy.

Use of Natural-Fiber Bio-Composites in Construction versus Traditional Solutions: Operational and Embodied Energy Assessment

PubMed Central

Galan-Marin, Carmen; Rivera-Gomez, Carlos; Garcia-Martinez, Antonio

2016-01-01

During the last decades natural polymers have become more and more frequent to replace traditional inorganic stabilizers in building materials. The purpose of this research is to establish a comparison between the most conventional building material solutions for load-bearing walls and a type of biomaterial. This comparison will focus on load-bearing walls as used in a widespread type of twentieth century dwelling construction in Europe and still used in developing countries nowadays. To carry out this analysis, the structural and thermal insulation characteristics of different construction solutions are balanced. The tool used for this evaluation is the life cycle assessment throughout the whole lifespan of these buildings. This research aims to examine the environmental performance of each material assessed: fired clay brick masonry walls (BW), concrete block masonry walls (CW), and stabilized soil block masonry walls (SW) stabilized with natural fibers and alginates. These conventional and new materials are evaluated from the point of view of both operational and embodied energy. PMID:28773586

How Properties of Kenaf Fibers from Burkina Faso Contribute to the Reinforcement of Earth Blocks

PubMed Central

Millogo, Younoussa; Aubert, Jean-Emmanuel; Hamard, Erwan; Morel, Jean-Claude

2015-01-01

Physicochemical characteristics of Hibiscus cannabinus (kenaf) fibers from Burkina Faso were studied using X-ray diffraction (XRD), infrared spectroscopy, thermal gravimetric analysis (TGA), chemical analysis and video microscopy. Kenaf fibers (3 cm long) were used to reinforce earth blocks, and the mechanical properties of reinforced blocks, with fiber contents ranging from 0.2 to 0.8 wt%, were investigated. The fibers were mainly composed of cellulose type I (70.4 wt%), hemicelluloses (18.9 wt%) and lignin (3 wt%) and were characterized by high tensile strength (1 ± 0.25 GPa) and Young’s modulus (136 ± 25 GPa), linked to their high cellulose content. The incorporation of short fibers of kenaf reduced the propagation of cracks in the blocks, through the good adherence of fibers to the clay matrix, and therefore improved their mechanical properties. Fiber incorporation was particularly beneficial for the bending strength of earth blocks because it reinforces these blocks after the failure of soil matrix observed for unreinforced blocks. Blocks reinforced with such fibers had a ductile tensile behavior that made them better building materials for masonry structures than unreinforced blocks.

Piezoelectric paper fabricated via nanostructured barium titanate functionalization of wood cellulose fibers.

PubMed

Mahadeva, Suresha K; Walus, Konrad; Stoeber, Boris

2014-05-28

We have successfully developed hybrid piezoelectric paper through fiber functionalization that involves anchoring nanostructured BaTiO3 into a stable matrix with wood cellulose fibers prior to the process of making paper sheets. This is realized by alternating immersion of wood fibers in a solution of poly(diallyldimethylammonium chloride) PDDA (+), followed by poly(sodium 4-styrenesulfonate) PSS (-), and once again in PDDA (+), resulting in the creation of a positively charged surface on the wood fibers. The treated wood fibers are then immersed in a BaTiO3 suspension, resulting in the attachment of BaTiO3 nanoparticles to the wood fibers due to a strong electrostatic interaction. Zeta potential measurements, X-ray diffraction, and microscopic and spectroscopic analysis imply successful functionalization of wood fibers with BaTiO3 nanoparticles without altering the hydrogen bonding and crystal structure of the wood fibers. The paper has the largest piezoelectric coefficient, d33 = 4.8 ± 0.4 pC N(-1), at the highest nanoparticle loading of 48 wt % BaTiO3. This newly developed piezoelectric hybrid paper is promising as a low-cost substrate to build sensing devices.

Exploring the effects of electrospinning processing protocols on fiber surface morphology and polymer chain conformation

NASA Astrophysics Data System (ADS)

Stephens, Jean S.

Electrospinning is a fiber formation technique that uses electrostatic forces to create continuous, nanometer diameter fibers. The work presented here focuses on the continuing efforts to build a stronger fundamental understanding of electrospinning by exploring structure/property/process relationships by investigating the effects of process protocols on fiber surface morphology and polymer chain conformation. By varying the processing parameters it has been possible to produce fibers with unique surface features, microtextured/nanoporous fibers and nanowebs. In the microtextured/nanoporous fiber studies, changing the solution concentration, solvent volatility, and relative humidity was found to alter the size, shape, and distribution of pores on the fiber surface. The mechanisms that can explain the pore formation and texturing on the surface of the fibers are phase separation (aggregation into polymer rich and polymer lean regions) and breath figures (evaporative cooling and vapor condensation). Through a judicious choice of the electrospinning processing parameters we have also been able to create "web" like structures of nanofibers (5--25 nm) from collagen, dragline silk analog, nylon, and denatured collagen. Electrostatic repulsion and thin film dewetting are thought to be responsible for the formation of the nanowebs. These unique structures were characterized using FESEM, TEM, OM, and AFM. Raman spectroscopy, initially developed as a "real time" characterization technique to study electrospun fiber formation, has also been used to investigate the effect of electrospinning on the chain conformation of bioinspired polymers. Comparing the spectrum of the bulk material to that of the electrospun material identified conformational changes in nylon 6 and dragline silk analog. The conformational change in nylon 6 (alpha-form to gamma-form) results from the stresses induced on the electrospinning jet during fiber formation, whereas the conformational change in the silk analog (beta-sheet to alpha-helical) result from electric field assembling of the charged a-helical segments of the protein polymer in solution. The investigations described here have allowed us to build a virtual database of the processing conditions needed to create materials for tissue engineering constructs. Electrospun collagen membranes have been used in preliminary cell attachment studies. From the trials it was observed that the cells migrated into the membranes indicating that the membranes are suitable for tissue engineering scaffolds.

Autocorrelation Function for Monitoring the Gap between The Steel Plates During Laser Welding

NASA Astrophysics Data System (ADS)

Mrna, Libor; Hornik, Petr

Proper alignment of the plates prior to laser welding represents an important factor that determines the quality of the resulting weld. A gap between the plates in a butt or overlap joint affects the oscillations of the keyhole and the surrounding weld pool. We present an experimental study of the butt and overlap welds with the artificial gap of the different thickness of the plates. The welds were made on a 2 kW fiber laser machine for the steel plates and the various welding parameters settings. The eigenfrequency of the keyhole oscillations and its changes were determined from the light emissions of the plasma plume using an autocorrelation function. As a result, we describe the relations between the autocorrelation characteristics, the thickness of the gap between plates and the weld geometry.

Flux density measurement of radial magnetic bearing with a rotating rotor based on fiber Bragg grating-giant magnetostrictive material sensors.

PubMed

Ding, Guoping; Zhang, Songchao; Cao, Hao; Gao, Bin; Zhang, Biyun

2017-06-10

The rotational magnetic field of radial magnetic bearings characterizes remarkable time and spatial nonlinearity due to the eddy current and induced electromagnetic field. It is significant to experimentally obtain the features of the rotational magnetic field of the radial magnetic bearings to validate the theoretical analysis and reveal the discipline of a rotational magnetic field. This paper developed thin-slice fiber Bragg grating-giant magnetostrictive material (FBG-GMM) magnetic sensors to measure air-gap flux density of a radial magnetic bearing with a rotating rotor; a radial magnetic bearing test rig was constructed and the rotational magnetic field with different rotation speed was measured. Moreover, the finite element method (FEM) was used to simulate the rotational magnetic field; the measurement results and FEM results were investigated, and it was concluded that the FBG-GMM sensors were capable of measuring the radial magnetic bearing's air gap flux density with a rotating rotor, and the measurement results showed a certain degree of accuracy.

Deformation and flexural properties of denture base polymer reinforced with glass fiber sheet.

PubMed

Kanie, Takahito; Arikawa, Hiroyuki; Fujii, Koichi; Ban, Seiji

2005-09-01

The purpose of this study was to investigate the deformation and flexural properties of acrylic and urethane polymers reinforced with glass fiber sheet. Four types of specimen--self-curing resin plate (R), light-curing oligomer plate containing a reinforcement (GO), and self-curing resin plate containing a reinforcement on one (GR) or both (GRG) sides--were prepared with three thicknesses: 1.5, 2.4, and 3.0 mm. Gaps between polymerized test specimen and a standard metal plate were measured at the corner (C), middle of the long sides (LS), and middle of the short sides (SS). The gaps for R were 0-2.0 microm. GO and GR markedly deformed at Points C, LS, and SS, and the degree of deformation increased as GO became thinner. Flexural strength was significantly increased by the reinforcement (p < 0.05). The flexural moduli of 3.0-mm thick R, GO, and GR were significantly smaller than that of 1.5-mm thick specimens.

Stochastic and Geometric Reasoning for Indoor Building Models with Electric Installations - Bridging the Gap Between GIS and Bim

NASA Astrophysics Data System (ADS)

Dehbi, Y.; Haunert, J.-H.; Plümer, L.

2017-10-01

3D city and building models according to CityGML encode the geometry, represent the structure and model semantically relevant building parts such as doors, windows and balconies. Building information models support the building design, construction and the facility management. In contrast to CityGML, they include also objects which cannot be observed from the outside. The three dimensional indoor models characterize a missing link between both worlds. Their derivation, however, is expensive. The semantic automatic interpretation of 3D point clouds of indoor environments is a methodically demanding task. The data acquisition is costly and difficult. The laser scanners and image-based methods require the access to every room. Based on an approach which does not require an additional geometry acquisition of building indoors, we propose an attempt for filling the gaps between 3D building models and building information models. Based on sparse observations such as the building footprint and room areas, 3D indoor models are generated using combinatorial and stochastic reasoning. The derived models are expanded by a-priori not observable structures such as electric installation. Gaussian mixtures, linear and bi-linear constraints are used to represent the background knowledge and structural regularities. The derivation of hypothesised models is performed by stochastic reasoning using graphical models, Gauss-Markov models and MAP-estimators.

Optical Fiber Design And Fabrication: Discussion On Recent Developments

NASA Astrophysics Data System (ADS)

Roy, Philippe; Devautour, Mathieu; Lavoute, Laure; Gaponov, Dmitry; Brasse, Gurvan; Hautreux, Stéphanie; Février, Sébastien; Restoin, Christine; Auguste, Jean-Louis; Gérôme, Frédéric; Humbert, Georges; Blondy, Jean-Marc

2008-10-01

Level of emitted power and beam quality of singlemode fiber lasers have been drastically increased at the expense of loss due to bend sensitivity, simplicity of manufacturing and packaging. Furthermore, the extension of the spectral coverage was primarily explored by exploiting non-linear effects, neglecting numerous possible transitions of rare earths. Through different research areas, we demonstrate the possibilities offered by new fiber designs and alternative methods of manufacturing. Photonic Band Gap fibers reconcile diffraction limited beam and large mode area with low bending loss. 80% slope efficiency is demonstrated together with a robust propagation allowing the fiber to be tightly bent until wounding radii as small as 6 cm. Highly ytterbium doped multimode core surrounded by high refractive index rods fiber exhibits a transverse singlemode behavior under continuous wave laser regime. A robust LP01 mode is observed and filtering effect is clearly observed. A non CVD process based on silica sand vitrification allows the synthesis of large and highly doped core with high index homogeneity, opening the way to design of efficient large mode area fiber lasers. 74% slope efficiency is measured, demonstrating the good quality of the core material. Finally, the use of rare earth (Er3+) doped zirconia nanocrystals in silica matrix offers a large panel of ignored energy transitions for visible or off-usual band of emission.

Dietary Fiber and the Human Gut Microbiota: Application of Evidence Mapping Methodology.

PubMed

Sawicki, Caleigh M; Livingston, Kara A; Obin, Martin; Roberts, Susan B; Chung, Mei; McKeown, Nicola M

2017-02-10

Interest is rapidly growing around the role of the human gut microbiota in facilitating beneficial health effects associated with consumption of dietary fiber. An evidence map of current research activity in this area was created using a newly developed database of dietary fiber intervention studies in humans to identify studies with the following broad outcomes: (1) modulation of colonic microflora; and/or (2) colonic fermentation/short-chain fatty acid concentration. Study design characteristics, fiber exposures, and outcome categories were summarized. A sub-analysis described oligosaccharides and bacterial composition in greater detail. One hundred eighty-eight relevant studies were identified. The fiber categories represented by the most studies were oligosaccharides (20%), resistant starch (16%), and chemically synthesized fibers (15%). Short-chain fatty acid concentration (47%) and bacterial composition (88%) were the most frequently studied outcomes. Whole-diet interventions, measures of bacterial activity, and studies in metabolically at-risk subjects were identified as potential gaps in the evidence. This evidence map efficiently captured the variability in characteristics of expanding research on dietary fiber, gut microbiota, and physiological health benefits, and identified areas that may benefit from further research. We hope that this evidence map will provide a resource for researchers to direct new intervention studies and meta-analyses.

Dietary Fiber and the Human Gut Microbiota: Application of Evidence Mapping Methodology

PubMed Central

Sawicki, Caleigh M.; Livingston, Kara A.; Obin, Martin; Roberts, Susan B.; Chung, Mei; McKeown, Nicola M.

2017-01-01

Interest is rapidly growing around the role of the human gut microbiota in facilitating beneficial health effects associated with consumption of dietary fiber. An evidence map of current research activity in this area was created using a newly developed database of dietary fiber intervention studies in humans to identify studies with the following broad outcomes: (1) modulation of colonic microflora; and/or (2) colonic fermentation/short-chain fatty acid concentration. Study design characteristics, fiber exposures, and outcome categories were summarized. A sub-analysis described oligosaccharides and bacterial composition in greater detail. One hundred eighty-eight relevant studies were identified. The fiber categories represented by the most studies were oligosaccharides (20%), resistant starch (16%), and chemically synthesized fibers (15%). Short-chain fatty acid concentration (47%) and bacterial composition (88%) were the most frequently studied outcomes. Whole-diet interventions, measures of bacterial activity, and studies in metabolically at-risk subjects were identified as potential gaps in the evidence. This evidence map efficiently captured the variability in characteristics of expanding research on dietary fiber, gut microbiota, and physiological health benefits, and identified areas that may benefit from further research. We hope that this evidence map will provide a resource for researchers to direct new intervention studies and meta-analyses. PMID:28208609

Gaussian Curvature Directs Stress Fiber Orientation and Cell Migration.

PubMed

Bade, Nathan D; Xu, Tina; Kamien, Randall D; Assoian, Richard K; Stebe, Kathleen J

2018-03-27

We show that substrates with nonzero Gaussian curvature influence the organization of stress fibers and direct the migration of cells. To study the role of Gaussian curvature, we developed a sphere-with-skirt surface in which a positive Gaussian curvature spherical cap is seamlessly surrounded by a negative Gaussian curvature draping skirt, both with principal radii similar to cell-length scales. We find significant reconfiguration of two subpopulations of stress fibers when fibroblasts are exposed to these curvatures. Apical stress fibers in cells on skirts align in the radial direction and avoid bending by forming chords across the concave gap, whereas basal stress fibers bend along the convex direction. Cell migration is also strongly influenced by the Gaussian curvature. Real-time imaging shows that cells migrating on skirts repolarize to establish a leading edge in the azimuthal direction. Thereafter, they migrate in that direction. This behavior is notably different from migration on planar surfaces, in which cells typically migrate in the same direction as the apical stress fiber orientation. Thus, this platform reveals that nonzero Gaussian curvature not only affects the positioning of cells and alignment of stress fiber subpopulations but also directs migration in a manner fundamentally distinct from that of migration on planar surfaces. Copyright © 2018 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Long-term high-level exercise promotes muscle reinnervation with age.

PubMed

Mosole, Simone; Carraro, Ugo; Kern, Helmut; Loefler, Stefan; Fruhmann, Hannah; Vogelauer, Michael; Burggraf, Samantha; Mayr, Winfried; Krenn, Matthias; Paternostro-Sluga, Tatjana; Hamar, Dusan; Cvecka, Jan; Sedliak, Milan; Tirpakova, Veronika; Sarabon, Nejc; Musarò, Antonio; Sandri, Marco; Protasi, Feliciano; Nori, Alessandra; Pond, Amber; Zampieri, Sandra

2014-04-01

The histologic features of aging muscle suggest that denervation contributes to atrophy, that immobility accelerates the process, and that routine exercise may protect against loss of motor units and muscle tissue. Here, we compared muscle biopsies from sedentary and physically active seniors and found that seniors with a long history of high-level recreational activity up to the time of muscle biopsy had 1) lower loss of muscle strength versus young men (32% loss in physically active vs 51% loss in sedentary seniors); 2) fewer small angulated (denervated) myofibers; 3) a higher percentage of fiber-type groups (reinnervated muscle fibers) that were almost exclusive of the slow type; and 4) sparse normal-size muscle fibers coexpressing fast and slow myosin heavy chains, which is not compatible with exercise-driven muscle-type transformation. The biopsies from the old physically active seniors varied from sparse fiber-type groupings to almost fully transformed muscle, suggesting that coexpressing fibers appear to fill gaps. Altogether, the data show that long-term physical activity promotes reinnervation of muscle fibers and suggest that decades of high-level exercise allow the body to adapt to age-related denervation by saving otherwise lost muscle fibers through selective recruitment to slow motor units. These effects on size and structure of myofibers may delay functional decline in late aging.

Shortening the decade-long gap between adult and paediatric drug formulations: a new framework based on the HIV experience in low- and middle-income countries.

PubMed

Penazzato, Martina; Lewis, Linda; Watkins, Melynda; Prabhu, Vineet; Pascual, Fernando; Auton, Martin; Kreft, Wesley; Morin, Sébastien; Vicari, Marissa; Lee, Janice; Jamieson, David; Siberry, George K

2018-02-01

Despite the coordinated efforts by several stakeholders to speed up access to HIV treatment for children, development of optimal paediatric formulations still lags 8 to 10 years behind that of adults, due mainly to lack of market incentives and technical complexities in manufacturing. The small and fragmented paediatric market also hinders launch and uptake of new formulations. Moreover, the problems affecting HIV similarly affect other disease areas where development and introduction of optimal paediatric formulations is even slower. Therefore, accelerating processes for developing and commercializing optimal paediatric drug formulations for HIV and other disease areas is urgently needed. The Global Accelerator for Paediatric Formulations (GAP-f) is an innovative collaborative model that will accelerate availability of optimized treatment options for infectious diseases, such as HIV, tuberculosis and viral hepatitis, affecting children in low- and middle-income countries (LMICs). It builds on the HIV experience and existing efforts in paediatric drug development, formalizing collaboration between normative bodies, research networks, regulatory agencies, industry, supply and procurement organizations and funding bodies. Upstream, the GAP-f will coordinate technical support to companies to design and study optimal paediatric formulations, harmonize efforts with regulators and incentivize manufacturers to conduct formulation development. Downstream, the GAP-f will reinforce coordinated procurement and communication with suppliers. The GAP-f will be implemented in a three-stage process: (1) development of a strategic framework and promotion of key regulatory efficiencies; (2) testing of feasibility and results, building on the work of existing platforms such as the Paediatric HIV Treatment Initiative (PHTI) including innovative approaches to incentivize generic development and (3) launch as a fully functioning structure. GAP-f is a key partnership example enhancing North-South and international cooperation on and access to science and technology and capacity building, responding to Sustainable Development Goal (SDG) 17.6 (technology) and 17.9. (capacity-building). By promoting access to the most needed paediatric formulations for HIV and high-burden infectious diseases in low-and middle-income countries, GAP-f will support achievement of SDG 3.2 (infant mortality), 3.3 (end of AIDS and combat other communicable diseases) and 3.8 (access to essential medicines), and be an essential component of meeting the global Start Free, Stay Free, AIDS Free super-fast-track targets. © 2018 World Health Organization; licensee IAS.

Production of fumaric acid by immobilized Rhizopus arrhizus RH 7-13-9# on loofah fiber in a stirred-tank reactor.

PubMed

Liu, Huan; Zhao, Shijie; Jin, Yuhan; Yue, Xuemin; Deng, Li; Wang, Fang; Tan, Tianwei

2017-11-01

Fumaric acid is an important building-block chemical. The production of fumaric acid by fermentation is possible. Loofah fiber is a natural, biodegradable, renewable polymer material with highly sophisticated and pore structure. This work investigated a new immobilization method using loofah fiber as carrier to produce fumaric acid in a stirred-tank reactor. Compared with other carriers, loofah fiber was proven to be efficiently and successfully used in the reactor. After the optimization process, 20g addition of loofah fiber and 400rpm agitation speed were chosen as the most suitable process conditions. 30.3g/L fumaric acid in the broth as well as 19.16g fumaric acid in the precipitation of solid was achieved, while the yield from glucose reached 0.211g/g. Three batches of fermentation using the same loofah fiber carrier were conducted successfully, which meant it provided a new method to produce fumaric acid in a stirred-tank reactor. Copyright © 2017. Published by Elsevier Ltd.

Direct writing of half-meter long CNT based fiber for flexible electronics.

PubMed

Huang, Sihan; Zhao, Chunsong; Pan, Wei; Cui, Yi; Wu, Hui

2015-03-11

Rapid construction of flexible circuits has attracted increasing attention according to its important applications in future smart electronic devices. Herein, we introduce a convenient and efficient "writing" approach to fabricate and assemble ultralong functional fibers as fundamental building blocks for flexible electronic devices. We demonstrated that, by a simple hand-writing process, carbon nanotubes (CNTs) can be aligned inside a continuous and uniform polymer fiber with length of more than 50 cm and diameters ranging from 300 nm to several micrometers. The as-prepared continuous fibers exhibit high electrical conductivity as well as superior mechanical flexibility (no obvious conductance increase after 1000 bending cycles to 4 mm diameter). Such functional fibers can be easily configured into designed patterns with high precision according to the easy "writing" process. The easy construction and assembly of functional fiber shown here holds potential for convenient and scalable fabrication of flexible circuits in future smart devices like wearable electronics and three-dimensional (3D) electronic devices.

Laboratory measurements of modal noise on optical fiber

NASA Astrophysics Data System (ADS)

Iuzzolino, M.; Sanna, N.; Tozzi, A.; Oliva, E.

Many scientific instruments are nowadays coupled to the telescope through optical fibers. This is also the case of the current configuration of GIANO, the high resolution near infrared echelle spectrograph installed at the TNG telescope. As experienced and frequent users of the IR optical fiber, the GIANO building team decided to go deep in the characterization of the optical fiber in the IR band, and in particular to understand and analyze the fiber modal noise. This work is also a preparatory study for the future HIRES@E-ELT instrument design. This paper consists in the description of the fiber laboratory tests, and in the explanation of the results. The whole job defines a wider comprehension of the modal noise, and demonstrates the existence of two aspects influencing this noise. The first one, well known in literature, refers to the interferences between the fiber modes at the exit endface of the fiber, and it can be mitigated by mechanical scrambling techniques. The second one, unknown before, is entirely dependent on the way in which light is injected at the entrance of the fiber, and no mitigation have been observed with any classical scrambling technique (e.g. double-scramblers). These considerations apply to both ZBLAN or fused silica optical fiber, and to both circular and octagonal core shape.

Transformer partial discharge monitoring based on optical fiber sensing

NASA Astrophysics Data System (ADS)

Wang, Kun; Tong, Xinglin; Zhu, Xiaolong

2014-06-01

The power transformer is the most important equipment of the high voltage power grid, however, some traditional methods of online partial discharge monitoring have some limitations. Based on many advantages of the optical fiber sensing technology, we have done some research on fiber optics Fabry-Perot (FP) sensing which can be useful for the transformer on online partial discharge monitoring. This research aimed at improving the reliability of power system safety monitoring. We have done some work as follows: designing a set for fiber optics FP sensor preparation, according to the fabrication procedure strictly making out the sensors, building a reasonable signal demodulation system for fiber optics FP sensing, doing a preliminary analysis about online partial discharge signal monitoring, including the research on different discharge intensities with the same measuring distance and different measuring distances with the same discharge intensity, and then making a detailed analysis of the experimental results.

Hierarchical Macro-meso-microporous ZSM-5 Zeolite Hollow Fibers With Highly Efficient Catalytic Cracking Capability

PubMed Central

Liu, Jia; Jiang, Guiyuan; Liu, Ying; Di, Jiancheng; Wang, Yajun; Zhao, Zhen; Sun, Qianyao; Xu, Chunming; Gao, Jinsen; Duan, Aijun; Liu, Jian; Wei, Yuechang; Zhao, Yong; Jiang, Lei

2014-01-01

Zeolite fibers have attracted growing interest for a range of new applications because of their structural particularity while maintaining the intrinsic performances of the building blocks of zeolites. The fabrication of uniform zeolite fibers with tunable hierarchical porosity and further exploration of their catalytic potential are of great importance. Here, we present a versatile and facile method for the fabrication of hierarchical ZSM-5 zeolite fibers with macro-meso-microporosity by coaxial electrospinning. Due to the synergistic integration of the suitable acidity and the hierarchical porosity, high yield of propylene and excellent anti-coking stability were demonstrated on the as-prepared ZSM-5 hollow fibers in the catalytic cracking reaction of iso-butane. This work may also provide good model catalysts with uniform wall thickness and tunable porosity for studying a series of important catalytic reactions. PMID:25450726

A Refractive Index Sensor Based on the Resonant Coupling to Cladding Modes in a Fiber Loop

PubMed Central

Reyes, Mauricio; Monzón-Hernández, David; Martínez-Ríos, Alejandro; Silvestre, Enrique; Díez, Antonio; Cruz, José Luis; Andrés, Miguel V.

2013-01-01

We report an easy-to-build, compact, and low-cost optical fiber refractive index sensor. It consists of a single fiber loop whose transmission spectra exhibit a series of notches produced by the resonant coupling between the fundamental mode and the cladding modes in a uniformly bent fiber. The wavelength of the notches, distributed in a wavelength span from 1,400 to 1,700 nm, can be tuned by adjusting the diameter of the fiber loop and are sensitive to refractive index changes of the external medium. Sensitivities of 170 and 800 nm per refractive index unit for water solutions and for the refractive index interval 1.40–1.442, respectively, are demonstrated. We estimate a long range resolution of 3 × 10−4 and a short range resolution of 2 × 10−5 for water solutions. PMID:23979478

Fiber Bragg grating ring resonators under rotation for angular velocity sensing.

PubMed

Campanella, C E; De Leonardis, F; Passaro, V M N

2015-05-20

In this paper we investigate the possibility of using hybrid resonators based on fiber Bragg grating ring resonators (FBGRRs) and π-shifted FBGRRs (i.e., defective FBGRRs) as rotation sensitive elements for gyroscope applications. In particular, we model the conventional fiber Bragg grating (FBG) with the coupled mode theory by taking into account how the Sagnac effect, induced by the rotation, modifies the eigenvalues, the photonic band gap, and the spectral response of the FBG. Then, on the basis of the FBG model under rotation conditions, the spectral responses of the FBGRR and π-FBGRR have been evaluated, confirming that the Sagnac effect manifests itself with a spectral shift of the eigensolutions. This physical investigation can be exploited for opening new ways in the optical gyroscope platforms.

Deodorizing Properties of Photocatalyst Textiles and Its Effect Analysis

NASA Astrophysics Data System (ADS)

Zhang, Hongxia; Ge, Caihong; Zhu, Chengyan; Li, Yanqing; Tian, Wei; Cheng, Dongzhi; Pan, Zhongxiang

In this paper, yarns of photocatalyst modified polyester staple fiber, cotton and blended yarn of bamboo fiber and photocatalyst modified polyester were selected. Series of woven fabric were manufactured.The photocatalyst fiber contents of woven fabrics were changed from 0% to 100% with 20% gap, that is 0%,40%,60%,80% and 100%. The deodorant performance of these fabrics were tested and analyzed, it can be concluded that when the content of the photocatalyst is 80% or 100%, the fabrics owns better deodorant; when the photocatalyst content in fabric is 40% or 60%, it has the deodorantion properties but the effect was not good. It can be shown from this experimental study that the deodorizing fabrics can be considered to develop if only the content of photocatalyst is above the 80%.

Thermal conductivity of cement stabilized earth bricks reinforced with date palm fiber

NASA Astrophysics Data System (ADS)

Berrehail, Tahar; Zemmouri, Noureddine; Agoudjil, Boudjemaa

2018-05-01

Recently, some cheap materials are available and adaptable to climate seem to meet current requirements. This paper investigates the thermal and mechanical properties of cement stabilized earth bricks(CSEB) reinforced with date palm fibers (DPF). The main goal is to develop and expand the field of use of these materials in the construction sector, and investigate the possibility of new bio composite as renewable, insulating building material with low cost, made of earth and reinforced with palm wood waste. In this study, a particular interest is brought to the thermal and mechanical characteristics, which constitute a decisive character for the choice of a building material. A series of earthen samples stabilized at 5% and reinforced with DPF of various fiber weight fractions, (5%, 10%), were manufactured and compacted applying two levels compacting, (5MPa and 10MPa). Compressive strength and thermal conductivity were experimentally studied; heating capacity and diffusivity were indirectly calculated. It was found that the fibrous reinforcement proved thermal conductivity and compressive strength. it also enhanced thermal performances. Thus, the results found allow us to investigate hygrothermal behaviour and its impact on occupants comfort.

Fiber-optic security monitoring sensor

NASA Astrophysics Data System (ADS)

Englund, Marja; Ipatti, Ari; Karioja, Pentti

1997-09-01

In security monitoring, fiber-optic sensors are advantageous because strong and rugged optical fibers are thin, light, flexible and immune to electromagnetic interference. Optical fibers packaged into cables, such as, building and underground cables, can be used to detect even slightest disturbances, movements, vibrations, pressure changes and impacts along their entire length. When running an optical cable around a structure, and when using speckle pattern recognition technique for alarm monitoring, the distributed monitoring of the structure is possible. The sensing cable can be strung along fences, buried underground, embedded into concrete, mounted on walls, floors and ceilings, or wrapped around the specific components. In this paper, a fiber-optic security monitoring sensor based on speckle pattern monitoring is described. The description of the measuring method and the results of the experimental fiber installations are given. The applicability of embedded and surface mounted fibers to monitor the pressure and impact induced vibrations of fences and concrete structures as well as the loosening of critical parts in a power plant machinery were demonstrated in field and laboratory conditions. The experiences related to the applications and optical cable types are also discussed.

Fiber optic security monitoring sensor

NASA Astrophysics Data System (ADS)

Englund, Marja; Ipatti, Ari; Karioja, Pentti

1997-09-01

In security monitoring, fiber-optic sensors are advantageous because strong and rugged optical fibers are thin, light, flexible and immune to electromagnetic interference. Optical fibers packaged into cables, such as, building and underground cables, can be used to detect even slightest disturbances, movements, vibrations, pressure changes and impacts along their entire length. When running an optical cable around a structure, and when using speckle pattern recognition technique for alarm monitoring, the distributed monitoring of the structure is possible. The sensing cable can be strung along fences, buried underground, embedded into concrete, mounted on walls, floors and ceilings, or wrapped around the specific components. In this paper, a fiber-optic security monitoring sensor based on speckle pattern monitoring is described. The description of the measuring method and the results of the experimental fiber installations are given. The applicability of embedded and surface mounted fibers to monitor the pressure and impact induced vibrations of fences and concrete structures as well as the loosening of critical parts in a power plant machinery were demonstrated in field and laboratory conditions. The experiences related to the applications and optical cable types are also discussed.

Manufacture of dissolving pulps from cornstalk by novel method coupling steam explosion and mechanical carding fractionation.

PubMed

Wang, Ning; Chen, Hong-Zhang

2013-07-01

In order to solve the inhomogeneity of cornstalk as fiber material to manufacture dissolving pulp, a novel method of steam explosion coupling mechanical carding was put forward to fractionate cornstalk long fiber for the production of cornstalk dissolving pulp. The fractionated long fiber had homogeneous structure and low hemicellulose and ash content. The fiber cell content was up to 85% in area, and the hemicellulose and ash content was 8.34% and 1.10% respectively. The α-cellulose content of cornstalk dissolving pulps was up to 93.10-97.10%, the viscosity was 14.37-23.96 mPas, and the yields of cornstalk dissolving pulps were from 10.11% to 12.44%. In addition, the fractionated short fiber was to be hydrolyzed by enzyme to build sugar platform. The constructed method of steam explosion coupling mechanical carding achieved the fractionation of cornstalk into long fiber and short fiber cleanly and effectively, and provided a new way for cornstalk integrated refinery. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effects of humidity and solution viscosity on electrospun fiber morphology.

PubMed

Nezarati, Roya M; Eifert, Michelle B; Cosgriff-Hernandez, Elizabeth

2013-10-01

Electrospinning is a popular technique to fabricate tissue engineering scaffolds due to the exceptional tunability of fiber morphology that can be used to control scaffold mechanical properties, degradation rate, and cell behavior. Although the effects of modulating processing or solution parameters on fiber morphology have been extensively studied, there remains limited understanding of the impact of environmental parameters such as humidity. To address this gap, three polymers (poly(ethylene glycol) [PEG], polycaprolactone [PCL], and poly(carbonate urethane) [PCU]) were electrospun at a range of relative humidities (RH = 5%-75%) and the resulting fiber architecture characterized with scanning electron microscopy. Low relative humidity (< 50%) resulted in fiber breakage for all three polymers due to decreased electrostatic discharge from the jet. At high relative humidity (> 50%), three distinct effects were observed based on individual polymer properties. An increase in fiber breakage and loss of fiber morphology occurred in the PEG system as a result of increased water absorption at high relative humidity. In contrast, surface pores on PCL fibers were observed and hypothesized to have formed via vapor-induced phase separation. Finally, decreased PCU fiber collection occurred at high humidity likely due to increased electrostatic discharge. These findings highlight that the effects of relative humidity on electrospun fiber morphology are dependent on polymer hydrophobicity, solvent miscibility with water, and solvent volatility. An additional study was conducted to highlight that small changes in molecular weight can strongly influence solution viscosity and resulting fiber morphology. We propose that solution viscosity rather than concentration is a more useful parameter to report in electrospinning methodology to enable reproduction of findings. In summary, this study further elucidates key mechanisms in electrospun fiber formation that can be utilized to fabricate tissue engineering scaffolds with tunable and reproducible properties.

Effects of Humidity and Solution Viscosity on Electrospun Fiber Morphology

PubMed Central

Nezarati, Roya M.; Eifert, Michelle B.

2013-01-01

Electrospinning is a popular technique to fabricate tissue engineering scaffolds due to the exceptional tunability of fiber morphology that can be used to control scaffold mechanical properties, degradation rate, and cell behavior. Although the effects of modulating processing or solution parameters on fiber morphology have been extensively studied, there remains limited understanding of the impact of environmental parameters such as humidity. To address this gap, three polymers (poly(ethylene glycol) [PEG], polycaprolactone [PCL], and poly(carbonate urethane) [PCU]) were electrospun at a range of relative humidities (RH=5%–75%) and the resulting fiber architecture characterized with scanning electron microscopy. Low relative humidity (<50%) resulted in fiber breakage for all three polymers due to decreased electrostatic discharge from the jet. At high relative humidity (>50%), three distinct effects were observed based on individual polymer properties. An increase in fiber breakage and loss of fiber morphology occurred in the PEG system as a result of increased water absorption at high relative humidity. In contrast, surface pores on PCL fibers were observed and hypothesized to have formed via vapor-induced phase separation. Finally, decreased PCU fiber collection occurred at high humidity likely due to increased electrostatic discharge. These findings highlight that the effects of relative humidity on electrospun fiber morphology are dependent on polymer hydrophobicity, solvent miscibility with water, and solvent volatility. An additional study was conducted to highlight that small changes in molecular weight can strongly influence solution viscosity and resulting fiber morphology. We propose that solution viscosity rather than concentration is a more useful parameter to report in electrospinning methodology to enable reproduction of findings. In summary, this study further elucidates key mechanisms in electrospun fiber formation that can be utilized to fabricate tissue engineering scaffolds with tunable and reproducible properties. PMID:23469941

Braided Carbon Fiber Rope Flow Characteristics. Degree awarded by Utah Univ.

NASA Technical Reports Server (NTRS)

Heman, J. R. C.; McCool, A. (Technical Monitor)

2000-01-01

I am submitting the following technical subject for consideration as a thesis topic for the master degree: The reusable solid rocket motor (RSRM) nozzle internal joints are being evaluated for the incorporation of a carbon fiber rope (CFR) as a thermal barrier. The CFR is approximately 0.260 in. diameter and is composed of approximately 12,000 carbon fibers, woven in ten sheaths or layers. The CFR is manufactured by a sub-tier vendor and subsequently several of its manufacturing details are proprietary to that vendor. The CFR design intent is to prevent hot motor combustion products and slag from intruding into the joint scaling area while still approaching a vented joint design to avoid the detriments of gas jet impingement. As a member of the Heat Transfer section at Thiokol Propulsion, two main goals exist as part of this NASA funded design effort: (1) development of flow model through the CFR and (2) development of a heat transfer model through the CFR. While both models are needed and most probably interrelated, the gas flow model is being targeted as the subject matter. Essentially, the topic would be "Modeling of Gas Flow through a Braided Carbon Fiber Rope". An AIAA journal or conference paper is being considered through Thiokol/NASA as well. A sub-scale CFR flow test fixture was designed to simulate the relative levels of CFR compression. The test fixture provides the means to measure gas mass flow rate upstream of the CFR and the pressure and temperature both upstream and downstream of the CFR. The test fixture was designed to eliminate the possibility of dynamic gapping at the CFR location and provide minimal flow resistance to ambient for gases exiting the rope. The data collected in the experiment will be evaluated to define a permeability/flow resistance model. Two possibilities exist for the flow characteristics through the CFR from choked flow to strictly friction driven. A test matrix for evaluating the CFR has been compiled, which addresses both of these characteristics. The range of pressures to be tested covers a relatively low delta pressure where non-choked flow is impossible, while the high pressure shown is dictated by the RSRM joint operating pressure where choking is possible. The test matrix, was also designed for a range of rope compressions or test fixture gaps ranging from 0.025" to 0.070". These gaps are controlled by the range of RSRM full-scale hardware joint gaps that will be expected by virtue of the joint design.

Statistical and Detailed Analysis on Fiber Reinforced Self-Compacting Concrete Containing Admixtures- A State of Art of Review

NASA Astrophysics Data System (ADS)

Athiyamaan, V.; Mohan Ganesh, G.

2017-11-01

Self-Compacting Concrete is one of the special concretes that have ability to flow and consolidate on its own weight, completely fill the formwork even in the presence of dense reinforcement; whilst maintaining its homogeneity throughout the formwork without any requirement for vibration. Researchers all over the world are developing high performance concrete by adding various Fibers, admixtures in different proportions. Various different kinds Fibers like glass, steel, carbon, Poly propylene and aramid Fibers provide improvement in concrete properties like tensile strength, fatigue characteristic, durability, shrinkage, impact, erosion resistance and serviceability of concrete[6]. It includes fundamental study on fiber reinforced self-compacting concrete with admixtures; its rheological properties, mechanical properties and overview study on design methodology statistical approaches regarding optimizing the concrete performances. The study has been classified into seven basic chapters: introduction, phenomenal study on material properties review on self-compacting concrete, overview on fiber reinforced self-compacting concrete containing admixtures, review on design and analysis of experiment; a statistical approach, summary of existing works on FRSCC and statistical modeling, literature review and, conclusion. It is so eminent to know the resent studies that had been done on polymer based binder materials (fly ash, metakaolin, GGBS, etc.), fiber reinforced concrete and SCC; to do an effective research on fiber reinforced self-compacting concrete containing admixtures. The key aim of the study is to sort-out the research gap and to gain a complete knowledge on polymer based Self compacting fiber reinforced concrete.

Dietary Fiber Future Directions: Integrating New Definitions and Findings to Inform Nutrition Research and Communication12

PubMed Central

Jones, Julie Miller

2013-01-01

The CODEX Alimentarius definition of dietary fiber includes all nondigestible carbohydrate polymers with a degree of polymerization of 3 or more as dietary fiber with the proviso that they show health benefits. The global definition, if accepted by all authoritative bodies, offers a chance for international harmonization in research, food composition tables, and food labeling. Its nonacceptance highlights problems that may develop when definitions vary by region. The definition requires that the research community agrees upon physiological effects for which there is substantial scientific agreement, e.g., fibers’ effects on laxation and gut health, on attenuating blood lipids and blood glucose and insulin, and in promoting fermentation in the large bowel. The definition also necessitates the delineation of research protocols to prove the benefits of various isolated and synthesized fibers. These should emanate from evidence-based reviews that fairly weigh epidemiological data while considering that added fibers are not reflected in many food composition databases. They then should include well-controlled, randomized, control trials and utilize animal studies to determine mechanisms. Agreement on many study variables such as the type of subject and the type of baseline diet that best fits the question under investigation will also be needed. Finally, the definition establishes that all types of fiber can address the severe fiber consumption gap that exists throughout the world by recognizing that the combination of fiber-rich and -fortified foods increases fiber intake while allowing consumers to stay within allowed energy levels. PMID:23319118

Intermediate filament mechanics in vitro and in the cell: from coiled coils to filaments, fibers and networks.

PubMed

Köster, Sarah; Weitz, David A; Goldman, Robert D; Aebi, Ueli; Herrmann, Harald

2015-02-01

Intermediate filament proteins form filaments, fibers and networks both in the cytoplasm and the nucleus of metazoan cells. Their general structural building plan accommodates highly varying amino acid sequences to yield extended dimeric α-helical coiled coils of highly conserved design. These 'rod' particles are the basic building blocks of intrinsically flexible, filamentous structures that are able to resist high mechanical stresses, that is, bending and stretching to a considerable degree, both in vitro and in the cell. Biophysical and computer modeling studies are beginning to unfold detailed structural and mechanical insights into these major supramolecular assemblies of cell architecture, not only in the 'test tube' but also in the cellular and tissue context. Copyright © 2015 Elsevier Ltd. All rights reserved.

Building Insulation Materials Compilation.

DTIC Science & Technology

1979-09-01

Fiber Rock or slag wool mineral fiber or mineral wool insulation is produced in a manner similar to that of fiberglass. In the U.S.A. the material most...commonly used to manufacture mineral wool is slag - from the production of steel, copper or lead. Rock wool and fiberglass are similar forms of...Insulation, Inc. Edina, Minnesota 55435 P.O. Box 188 (612) 835-3717 2705 West Highway 55 Hamel, Minnesota 55340 Casco Mineral Wool Division (612) 478-6614

The international implications of national and local coordination on building energy codes: Case studies in six cities

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

Evans, Meredydd; Yu, Sha; Staniszewski, Aaron

Building energy efficiency is an important strategy for reducing greenhouse gas emissions globally. In fact, 55 countries have included building energy efficiency in their Nationally Determined Contributions (NDCs) under the Paris Agreement. This research uses building energy code implementation in six cities across different continents as case studies to assess what it may take for countries to implement the ambitions of their energy efficiency goals. Specifically, we look at the cases of Bogota, Colombia; Da Nang, Vietnam; Eskisehir, Turkey; Mexico City, Mexico; Rajkot, India; and Tshwane, South Africa, all of which are “deep dive” cities under the Sustainable Energy formore » All's Building Efficiency Accelerator. The research focuses on understanding the baseline with existing gaps in implementation and coordination. The methodology used a combination of surveys on code status and interviews with stakeholders at the local and national level, as well as review of published documents. We looked at code development, implementation, and evaluation. The cities are all working to improve implementation, however, the challenges they currently face include gaps in resources, capacity, tools, and institutions to check for compliance. Better coordination between national and local governments could help improve implementation, but that coordination is not yet well established. For example, all six of the cities reported that there was little to no involvement of local stakeholders in development of the national code; only one city reported that it had access to national funding to support code implementation. More robust coordination could better link cities with capacity building and funding for compliance, and ensure that the code reflects local priorities. By understanding gaps in implementation, it can also help in designing more targeted interventions to scale up energy savings.« less

The international implications of national and local coordination on building energy codes: Case studies in six cities

DOE PAGES

Evans, Meredydd; Yu, Sha; Staniszewski, Aaron; ...

2018-04-17

Building energy efficiency is an important strategy for reducing greenhouse gas emissions globally. In fact, 55 countries have included building energy efficiency in their Nationally Determined Contributions (NDCs) under the Paris Agreement. This research uses building energy code implementation in six cities across different continents as case studies to assess what it may take for countries to implement the ambitions of their energy efficiency goals. Specifically, we look at the cases of Bogota, Colombia; Da Nang, Vietnam; Eskisehir, Turkey; Mexico City, Mexico; Rajkot, India; and Tshwane, South Africa, all of which are “deep dive” cities under the Sustainable Energy formore » All's Building Efficiency Accelerator. The research focuses on understanding the baseline with existing gaps in implementation and coordination. The methodology used a combination of surveys on code status and interviews with stakeholders at the local and national level, as well as review of published documents. We looked at code development, implementation, and evaluation. The cities are all working to improve implementation, however, the challenges they currently face include gaps in resources, capacity, tools, and institutions to check for compliance. Better coordination between national and local governments could help improve implementation, but that coordination is not yet well established. For example, all six of the cities reported that there was little to no involvement of local stakeholders in development of the national code; only one city reported that it had access to national funding to support code implementation. More robust coordination could better link cities with capacity building and funding for compliance, and ensure that the code reflects local priorities. By understanding gaps in implementation, it can also help in designing more targeted interventions to scale up energy savings.« less

The missing links between planning and budgeting. Keys to survival in an era of entrepreneurialism.

PubMed

Rice, J A; Garside, P M

1984-03-01

For hospitals to survive the challenges of their turbulent environment, they must build stronger links between their planning and budgeting processes. Hospitals have traditionally experienced a gap between their long-range plans and short-range budgets. This article examines the scope, nature, and causes of this gap; clarifies the need to bridge this gap; and then discusses three major initiatives (missing links) to bridge the gap. Implications of these missing links for the hospital's board, physicians, managers, and systems are also described.

Developing health information literacy: a needs analysis from the perspective of preprofessional health students.

PubMed

Ivanitskaya, Lana V; Hanisko, Kaitlyn A; Garrison, Julie A; Janson, Samantha J; Vibbert, Danielle

2012-10-01

The research identified the skills, if any, that health preprofessional students wished to develop after receiving feedback on skill gaps as well as any strategies they intended to use to address these gaps. A qualitative approach was used to elicit students' reflections on building health information literacy skills. First, the students took the Research Readiness Self-Assessment instrument, which measured their health information literacy, and then they received individually tailored feedback about their scores and skill gaps. Second, students completed a post-assessment survey asking how they intended to close identified gaps in their skills on these. Three trained coders analyzed qualitative comments by 181 students and grouped them into themes relating to "what skills to improve" and "how to improve them." Students intended to develop library skills (64% of respondents), Internet skills (63%), and information evaluation skills (63%). Most students reported that they would use library staff members' assistance (55%), but even more respondents (82%) planned to learn the skills by practicing on their own. Getting help from librarians was a much more popular learning strategy than getting assistance from peers (20%) or professors (17%). The study highlighted the importance of providing health preprofessional students with resources to improve skills on their own, remote access to library staff members, and instruction on the complexity of building health literacy skills, while also building relationships among students, librarians, and faculty.

On the role of CFRP reinforcement for wood beams stiffness

NASA Astrophysics Data System (ADS)

Ianasi, A. C.

2015-11-01

In recent years, carbon fiber composites have been increasingly used in different ways in reinforcing structural elements. Specifically, the use of composite materials as a reinforcement for wood beams under bending loads requires paying attention to several aspects of the problem such as the number of the composite layers applied on the wood beams. Study consolidation of composites revealed that they are made by bonding fibrous material impregnated with resin on the surface of various elements, to restore or increase the load carrying capacity (bending, cutting, compression or torque) without significant damage of their rigidity. Fibers used in building applications can be fiberglass, aramid or carbon. Items that can be strengthened are concrete, brick, wood, steel and stone, and in terms of structural beams, walls, columns and floors. This paper describes an experimental study which was designed to evaluate the effect of composite material on the stiffness of the wood beams. It proposes a summary of the fundamental principles of analysis of composite materials and the design and use. The type of reinforcement used on the beams is the carbon fiber reinforced polymer (CFRP) sheet and plates and also an epoxy resin for bonding all the elements. Structural epoxy resins remain the primary choice of adhesive to form the bond to fiber-reinforced plastics and are the generally accepted adhesives in bonded CFRP-wood connections. The advantages of using epoxy resin in comparison to common wood-laminating adhesives are their gap-filling qualities and the low clamping pressures that are required to form the bond between carbon fiber plates or sheets and the wood beams. Mechanical tests performed on the reinforced wood beams showed that CFRP materials may produce flexural displacement and lifting increases of the beams. Observations of the experimental load-displacement relationships showed that bending strength increased for wood beams reinforced with CFRP composite plates and sheets compared to those without CFRP reinforcement. The main conclusion of the tests is that the tensioning forces allow beam taking a maximum load for a while, something that is particularly useful when we consider a real construction, so in case of excess lift beam, we have time to take strengthening measures and when is about a catastrophic request (earthquake) the construction remain partially functional. The experiments have shown that the method of increasing resistance of wood constructions with composite materials is good for it. The solution is easy to implement and has low costs.

Building Cultural Bridges with Aboriginal Learners and Their "Classmates" for Transformative Environmental Education

ERIC Educational Resources Information Center

Hatcher, Annamarie

2012-01-01

The educational gap between Aboriginal and non-Aboriginal Canadians is the most significant social policy challenge facing Canada (Richards 2008). This gap is particularly evident in the science fields. Educational institutions are still regarded as mechanisms of colonization by many Aboriginal people. Their "foreign" Eurocentric (or…

Manipulation of spontaneous emission in a tapered photonic crystal fibre

NASA Astrophysics Data System (ADS)

Myers, S. J.; Fussell, D. P.; Dawes, J. M.; Mägi, E.; McPhedran, R. C.; Eggleton, B. J.; de Sterke, C. Martijn

2006-12-01

We characterize the spontaneous emission of dye that is introduced into the central core of a tapered photonic crystal fiber. Since the photonic crystal period in the fibre cladding varies along the taper, the transmission and spontaneous emission spectra over a wide range of relative frequencies can be observed. The spontaneous emission spectra of the fibre transverse to the fiber axis show suppression due to partial band-gaps of the structure, and also enhancement of spontaneous emission near the band edges. We associate these with van Hove features, as well as finite cluster size effects.

The development of the experimental setup for measuring the cell membrane electrical potential by Sucrose-Gap Technique

NASA Astrophysics Data System (ADS)

Yuzhakov, AD; Nosarev, AV; Aleinik, AN

2017-11-01

This article describes the development of the experimental setup for measuring the cell membrane electrical potential by Double -Sucrose-Gap Technique. The double-gap isolation method allows the simultaneous measurement of electrical activity and tension output from contracting segments of muscle fibers. This technique has been widely used as a convenient tool for recording of the membrane activities from myelinated or unmyelinated nerves and muscle preparations. This device can be an effective way to provide undergraduate biomedical engineering students with invaluable experiences in neurophysiology. The installation design and its main characteristics are described. The advantages of the described device are the simplicity of the experiment, relatively low cost, the possibility of long-term experiment.

FlySPEX: a flexible multi-angle spectropolarimetric sensing system

NASA Astrophysics Data System (ADS)

Snik, Frans; Keller, Christoph U.; Wijnen, Merijn; Peters, Hubert; Derks, Roy; Smulders, Edwin

2016-05-01

Accurate multi-angle spectropolarimetry permits the detailed and unambiguous characterization of a wide range of objects. Science cases and commercial applications include atmospheric aerosol studies, biomedical sensing, and food quality control. We introduce the FlySPEX spectropolarimetric fiber-head that constitutes the essential building block of a novel multi-angle sensing system. A combination of miniaturized standard polarization optics inside every fiber-head encodes the full linear polarization information as a spectral modulation of the light that enters two regular optical fibers. By orienting many FlySPEX fiber-heads in any desired set of directions, a fiber bundle contains the complete instantaneous information on polarization as a function of wavelength and as a function of the set of viewing directions. This information is to be recorded by one or several multi-fiber spectrometers. Not only is this system flexible in the amount of viewing directions and their configuration, it also permits multiplexing different wavelength ranges and spectral resolutions by implementing different spectrometers. We present the design and prototyping for a FlySPEX fiber-head that is optimized for both polarimetric accuracy and commercial series production. We integrate the polarimetric calibration of each FlySPEX fiber-head in the manufacturing process.

Hollow fiber: a biophotonic implant for live cells

NASA Astrophysics Data System (ADS)

Silvestre, Oscar F.; Holton, Mark D.; Summers, Huw D.; Smith, Paul J.; Errington, Rachel J.

2009-02-01

The technical objective of this study has been to design, build and validate biocompatible hollow fiber implants based on fluorescence with integrated biophotonics components to enable in fiber kinetic cell based assays. A human osteosarcoma in vitro cell model fiber system has been established with validation studies to determine in fiber cell growth, cell cycle analysis and organization in normal and drug treated conditions. The rationale for implant development have focused on developing benchmark concepts in standard monolayer tissue culture followed by the development of in vitro hollow fiber designs; encompassing imaging with and without integrated biophotonics. Furthermore the effect of introducing targetable biosensors into the encapsulated tumor implant such as quantum dots for informing new detection readouts and possible implant designs have been evaluated. A preliminary micro/macro imaging approach has been undertaken, that could provide a mean to track distinct morphological changes in cells growing in a 3D matrix within the fiber which affect the light scattering properties of the implant. Parallel engineering studies have showed the influence of the optical properties of the fiber polymer wall in all imaging modes. Taken all together, we show the basic foundation and the opportunities for multi-modal imaging within an in vitro implant format.

Excitation of resonances of microspheres on an optical fiber.

PubMed

Serpengüzel, A; Arnold, S; Griffel, G

1995-04-01

Morphology-dependent resonances (MDR's) of solid microspheres are excited by using an optical fiber coupler. The narrowest measured MDR linewidths are limited by the excitation laser linewidth (<0.025 nm). Only MDR's, with an on-resonance to off-resonance intensity ratio of 10(4), contribute to scattering. The intensity of various resonance orders is understood by the localization principle and the recently developed generalized Lorentz-Mie theory. The microsphere fiber system has potential for becoming a building block in dispersive microphotonics. The basic physics underlying our approach may be considered a harbinger for the coupling of active photonic microstructures such as microdisk lasers.

Physical properties of recycled PET non-woven fabrics for buildings

NASA Astrophysics Data System (ADS)

Üstün Çetin, S.; Tayyar, A. E.

2017-10-01

Recycled fibers have been commonly used in non-woven production technology for engineering applications such as textile engineering and civil engineering. Nonwovens including recycled fibers can be utilized in insulation, roofing and floor separation applications. In this study, physical performance properties such as drape, bending resistance, tensile strength, and breaking elongation values of non-woven fabrics consisting of v-PET (virgin) and r-PET (recycled) fibers in five different blend ratios are examined comparatively. The test results indicated that r-PET can be used in non-wovens for civil engineering applications such as insulation, roofing and floor separation fulfilling the acceptable quality level values.

47 CFR 32.2426 - Intrabuilding network cable.

Code of Federal Regulations, 2013 CFR

2013-10-01

...) Nonmetallic cable. This subsidiary record category shall include the original cost of optical fiber cable and... between buildings on one customer's same premises. Intrabuilding network cables are used to distribute...

47 CFR 32.2426 - Intrabuilding network cable.

Code of Federal Regulations, 2014 CFR

2014-10-01

...) Nonmetallic cable. This subsidiary record category shall include the original cost of optical fiber cable and... between buildings on one customer's same premises. Intrabuilding network cables are used to distribute...

47 CFR 32.2426 - Intrabuilding network cable.

Code of Federal Regulations, 2012 CFR

2012-10-01

...) Nonmetallic cable. This subsidiary record category shall include the original cost of optical fiber cable and... between buildings on one customer's same premises. Intrabuilding network cables are used to distribute...

Interior. Plantcrushing and fiberprocessing apparatus used in latexextraction experiments. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Interior. Plant-crushing and fiber-processing apparatus used in latex-extraction experiments. - Thomas A. Edison Laboratories, Building No. 2, Main Street & Lakeside Avenue, West Orange, Essex County, NJ

Interior. Plantcrushing and fiberprocessing equipment used in latexextraction experiments. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Interior. Plant-crushing and fiber-processing equipment used in latex-extraction experiments. - Thomas A. Edison Laboratories, Building No. 2, Main Street & Lakeside Avenue, West Orange, Essex County, NJ

The Impact Of Multimode Fiber Chromatic Dispersion On Data Communications

NASA Astrophysics Data System (ADS)

Hackert, Michael J.

1990-01-01

Capability for the lowest cost is the goal of contemporary communications managers. With all of the competitive pressures that modern businesses are experiencing these days, communications needs must be met with the most information carrying capacity for the lowest cost. Optical fiber communication systems meet these requirements while providing reliability, system integrity, and potential future upgradability. Consequently, optical fiber is finding numerous applications in addition to its traditional telephony plant. Fiber based systems are meeting these requirements in building networks and computer interconnects at a lower cost than copper based systems. A fiber type being chosen by industry to meet these needs in standard systems such as FDDI, is multimode fiber. Multimode fiber systems offer cost advantages over single-mode fiber through lower fiber connection costs. Also, system designers can gain savings by using low cost, high reliability, wide spectral width sources such as LEDs instead of lasers and by operating at higher bit rates than used for multimode systems in the past. However, in order to maximize the cost savings while ensuring the system will operate as intended, the chromatic dispersion of the fiber must be taken into account. This paper explains how to do that and shows how to calculate multimode chromatic dispersion for each of the standard fiber sizes (50 μm, 62.5 μm, 85 μm, and 100μm core diameter).

Carbon Fiber Manufacturing Facility Siting and Policy Considerations: International Comparison

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

Cook, Jeffrey J.; Booth, Samuel

Carbon fiber is increasingly used in a wide variety of applications due largely to its superior material properties such as high strength-to-weight ratio. The current global carbon fiber manufacturing industry is predominately located in China, Europe, Japan, and the United States. The carbon fiber market is expected to expand significantly through 2024 and to require additional manufacturing capacity to meet demand. Carbon fiber manufacturing facilities can offer significant economic development and employment opportunities as exemplified by the $1 billion investment and 500 jobs expected at a new Toray plant in Moore, South Carolina. Though the market is expected to expand,more » it is unclear where new manufacturing facilities will locate to meet demand. This uncertainty stems from the lack of research evaluating how different nations with significant carbon fiber manufacturing capacity compare as it relates to certain manufacturing facility siting factors such as costs of labor and energy as well as policy directed at supporting carbon fiber development, domestic deployment, and exports. This report fills these gaps by evaluating the top carbon fiber manufacturing countries, including China, European Union countries, Japan, Mexico, South Korea, Taiwan, and the United States. The report documents how the United States compares to these countries based on a range of manufacturing siting considerations and existing policies related to carbon fiber. It concludes with a discussion of various policy options the United States could adopt to both (1) increase the competitiveness of the United States as it relates to attracting new carbon fiber manufacturing and (2) foster broader end-use markets for deployment.« less

Radiation hardening of optical fibers and fiber sensors for space applications: recent advances

NASA Astrophysics Data System (ADS)

Girard, S.; Ouerdane, Y.; Pinsard, E.; Laurent, A.; Ladaci, A.; Robin, T.; Cadier, B.; Mescia, L.; Boukenter, A.

2017-11-01

In these ICSO proceedings, we review recent advances from our group concerning the radiation hardening of optical fiber and fiber-based sensors for space applications and compare their benefits to state-of-the-art results. We focus on the various approaches we developed to enhance the radiation tolerance of two classes of optical fibers doped with rare-earths: the erbium (Er)-doped ones and the ytterbium/erbium (Er/Yb)-doped ones. As a first approach, we work at the component level, optimizing the fiber structure and composition to reduce their intrinsically high radiation sensitivities. For the Erbium-doped fibers, this has been achieved using a new structure for the fiber that is called Hole-Assisted Carbon Coated (HACC) optical fibers whereas for the Er/Ybdoped optical fibers, their hardening was successfully achieved adding to the fiber, the Cerium element, that prevents the formation of the radiation-induced point defects responsible for the radiation induced attenuation in the infrared part of the spectrum. These fibers are used as part of more complex systems like amplifiers (Erbium-doped Fiber Amplifier, EDFA or Yb-EDFA) or source (Erbium-doped Fiber Source, EDFS or Yb- EDFS), we discuss the impact of using radiation-hardened fibers on the system radiation vulnerability and demonstrate the resistance of these systems to radiation constraints associated with today and future space missions. Finally, we will discuss another radiation hardening approach build in our group and based on a hardening-by-system strategy in which the amplifier is optimized during its elaboration for its future mission considering the radiation effects and not in-lab.

Evidence-Based Approach to Fiber Supplements and Clinically Meaningful Health Benefits, Part 1

PubMed Central

McRorie, Johnson W.

2015-01-01

Dietary fiber that is intrinsic and intact in fiber-rich foods (eg, fruits, vegetables, legumes, whole grains) is widely recognized to have beneficial effects on health when consumed at recommended levels (25 g/d for adult women, 38 g/d for adult men). Most (90%) of the US population does not consume this level of dietary fiber, averaging only 15 g/d. In an attempt to bridge this “fiber gap,” many consumers are turning to fiber supplements, which are typically isolated from a single source. Fiber supplements cannot be presumed to provide the health benefits that are associated with dietary fiber from whole foods. Of the fiber supplements on the market today, only a minority possess the physical characteristics that underlie the mechanisms driving clinically meaningful health benefits. The first part (current issue) of this 2-part series will focus on the 4 main characteristics of fiber supplements that drive clinical efficacy (solubility, degree/rate of fermentation, viscosity, and gel formation), the 4 clinically meaningful designations that identify which health benefits are associated with specific fibers, and the gel-dependent mechanisms in the small bowel that drive specific health benefits (eg, cholesterol lowering, improved glycemic control). The second part (next issue) of this 2-part series will focus on the effects of fiber supplements in the large bowel, including the 2 mechanisms by which fiber prevents/relieves constipation (insoluble mechanical irritant and soluble gel-dependent water-holding capacity), the gel-dependent mechanism for attenuating diarrhea and normalizing stool form in irritable bowel syndrome, and the combined large bowel/small bowel fiber effects for weight loss/maintenance. The second part will also discuss how processing for marketed products can attenuate efficacy, why fiber supplements can cause gastrointestinal symptoms, and how to avoid symptoms for better long-term compliance. PMID:25972618

Evidence-Based Approach to Fiber Supplements and Clinically Meaningful Health Benefits, Part 2

PubMed Central

McRorie, Johnson W.

2015-01-01

Dietary fiber that is intrinsic and intact in fiber-rich foods (eg, fruits, vegetables, legumes, whole grains) is widely recognized to have beneficial effects on health when consumed at recommended levels (25 g/d for adult women, 38 g/d for adult men). Most (90%) of the US population does not consume this level of dietary fiber, averaging only 15 g/d. In an attempt to bridge this “fiber gap,” many consumers are turning to fiber supplements, which are typically isolated from a single source. Fiber supplements cannot be presumed to provide the health benefits that are associated with dietary fiber from whole foods. Of the fiber supplements on the market today, only a minority possess the physical characteristics that underlie the mechanisms driving clinically meaningful health benefits. In this 2-part series, the first part (previous issue) described the 4 main characteristics of fiber supplements that drive clinical efficacy (solubility, degree/rate of fermentation, viscosity, and gel formation), the 4 clinically meaningful designations that identify which health benefits are associated with specific fibers, and the gel-dependent mechanisms in the small bowel that drive specific health benefits (eg, cholesterol lowering, improved glycemic control). The second part (current issue) of this 2-part series will focus on the effects of fiber supplements in the large bowel, including the 2 mechanisms by which fiber prevents/relieves constipation (insoluble mechanical irritant and soluble gel-dependent water-holding capacity), the gel-dependent mechanism for attenuating diarrhea and normalizing stool form in irritable bowel syndrome, and the combined large bowel/small bowel fiber effects for weight loss/maintenance. The second part will also discuss how processing for marketed products can attenuate efficacy, why fiber supplements can cause gastrointestinal symptoms, and how to avoid symptoms for better long-term compliance. PMID:25972619

Influence of the Gap Width on the Geometry of the Welded Joint in Hybrid Laser-Arc Welding

NASA Astrophysics Data System (ADS)

Turichin, G.; Tsibulskiy, I.; Kuznetsov, M.; Akhmetov, A.; Mildebrath, M.; Hassel, T.

The aim of this research was the experimental investigation of the influence of the gap width and speed of the welding wire on the changes of the geometry in the welded joint in the hybrid laser-arc welding of shipbuilding steel RS E36. The research was divided into three parts. First, in order to understand the influence of the gap width on the welded joint geometry, experimental research was done using continuous wave fiber laser IPG YLS-15000 with arc rectifier VDU-1500DC. The second part involved study of the geometry of the welded joint and hardness test results. Three macrosections from each welded joint were obtained. Influence of the gap width and welding wire speed on the welded joint geometry was researched in the three lines: in the right side of the plates, middle welded joint and in the root welded joint.

Action potentials recorded from bundles of very thin, gray matter axons in rat cerebellar slices using a grease-gap method.

PubMed

Palani, Damodharan; Pekala, Dobromila; Baginskas, Armantas; Szkudlarek, Hanna; Raastad, Morten

2012-07-15

We investigated the ability of a grease-gap method to record fast and slow changes of the membrane potential from bundles of gray matter axons. Their membrane potentials are of particular interest because these axons are different from most axons that have been investigated using intra-axonal or gap techniques. One of the main differences is that gray matter axons typically have closely spaced presynaptic specializations, called boutons or varicosities, distributed along their entire paths. In response to electrical activation of bundles of parallel fiber axons we were able to record small (128-416μV) but stable signals that we show most likely represented a fraction of the trans-membrane action potentials. A less-than 100% fraction prevents measurements of absolute values for membrane potentials, but the good signal-to-noise ratio (typically 10-16) allows detection of changes in resting membrane potential, action potentials and their after-potentials. Because very little is known about the shape of action potentials and after-potentials in these axons we used several independent methods to make it likely that the grease-gap signal was of intra-axonal origin. We demonstrate the utility of the method by showing that the action potentials in cerebellar parallel fibers and hippocampal Schaffer collaterals had a slowly decaying, depolarized after-potential. The method is ideal for pharmacological tests, which we demonstrate by showing that the slow after-potential was sensitive to 4-AP, and that the membrane potential was reduced by 200μM Ba(2+). Copyright © 2012 Elsevier B.V. All rights reserved.

Municipal Broadband in Wilson, North Carolina: A Study

ERIC Educational Resources Information Center

O'Boyle, Timothy

2012-01-01

Relatively little empirical attention has been paid to the political economy of publicly-retailed fiber-optic broadband internet service. To address this gap in the literature, this dissertation examines the history, dynamics and trends in the municipal broadband movement. In specific, Wilson, North Carolina's Greenlight service is examined in…

Scalable air cathode microbial fuel cells using glass fiber separators, plastic mesh supporters, and graphite fiber brush anodes.

PubMed

Zhang, Xiaoyuan; Cheng, Shaoan; Liang, Peng; Huang, Xia; Logan, Bruce E

2011-01-01

The combined use of brush anodes and glass fiber (GF1) separators, and plastic mesh supporters were used here for the first time to create a scalable microbial fuel cell architecture. Separators prevented short circuiting of closely-spaced electrodes, and cathode supporters were used to avoid water gaps between the separator and cathode that can reduce power production. The maximum power density with a separator and supporter and a single cathode was 75 ± 1 W/m(3). Removing the separator decreased power by 8%. Adding a second cathode increased power to 154 ± 1 W/m(3). Current was increased by connecting two MFCs connected in parallel. These results show that brush anodes, combined with a glass fiber separator and a plastic mesh supporter, produce a useful MFC architecture that is inherently scalable due to good insulation between the electrodes and a compact architecture. Copyright © 2010 Elsevier Ltd. All rights reserved.

Optical fibre PH sensor based on immobilized indicator

NASA Astrophysics Data System (ADS)

Cai, Defu; Cao, Qiang; Han, JingHong; Cai, Jine; Li, YaTing; Zhu, ZeMin; Fan, Jie; Gao, Ning

1991-08-01

An optical fiber pH sensor which has the immobilized pH sensitive indicator dye reagents on the tip of the optical fiber has been studied. The probe is made by covalently immobilizing the phenol red, bromine phenol blue, or bromothymol blue on the polyacrylamide microsphere fixed by polyterafluoroethylene (PTFE) film. A gap between the dye and optical fiber was used to make the diffusion of the hydrogen ions easier. The parameters of the optical fiber pH sensor have been given completely. The ranges of measurement are 3.0 - 5.0 pH, 7.0 - 8.5 pH, and 8.0 - 10.0 pH for bromine phenol blue, phenol red, and bromothymol blue, respectively. The sensitivity is 66.6 mV/pH. The probe has a precision of better than 0.55 pH. The linear correlation coefficient is 0.999. The response time is 1 - 2 min. The hysteresis is 0.52%. The repeatability is 0.013 mV, while the stability is 0.015 pH/h.

Shear transfer in concrete reinforced with carbon fibers

NASA Astrophysics Data System (ADS)

El-Mokadem, Khaled Mounir

2001-10-01

Scope and method of study. The research started with preliminary tests and studies on the behavior and effect of carbon fibers in different water solutions and mortar/concrete mixes. The research work investigated the use of CF in the production of concrete pipes and prestressed concrete double-tee sections. The research then focused on studying the effect of using carbon fibers on the direct shear transfer of sand-lightweight reinforced concrete push-off specimens. Findings and conclusions. In general, adding carbon fibers to concrete improved its tensile characteristics but decreased its compressive strength. The decrease in compressive strength was due to the decrease in concrete density as fibers act as three-dimensional mesh that entrapped air. The decrease in compressive strength was also due to the increase in the total surface area of non-cementitious material in the concrete. Sand-lightweight reinforced concrete push-off specimens with carbon fibers had lower shear carrying capacity than those without carbon fibers for the same cement content in the concrete. Current building codes and specifications estimate the shear strength of concrete as a ratio of the compressive strength. If applying the same principals then the ratio of shear strength to compressive strength for concrete reinforced with carbon fibers is higher than that for concrete without carbon fibers.

Plasma vitrification of asbestos fibers

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

Camacho, S.L.

Asbestos is a mineral in the form of long, thread-like fibers. Asbestos fibers have been among the best insulators of pipes, boilers, ducts, tanks, etc., in buildings, ships, and industrial furnaces. Over 150,000 metric tons of asbestos were consumed in the United States in 1984. The Environmental Protection Agency has declared asbestos fibers a known human carcinogen. And today, asbestos insulators are being replaced by manmade non-hazardous fibers. Millions of tons of replaced asbestos fiber insulators are in storage, awaiting the demonstration of effective alternative disposal technologies. Plasma vitrification has been demonstrated during May, June and July 1995 as amore » viable, cost-effective, safe technology for asbestos fiber disposal. A low-mass plasma arc heater is submerged under the waste asbestos insulating materials, and the intense heat of the plasma flame heats and melts the fibers. The by-product is dark, non-hazardous glass pellets. The vitrification process renders the asbestos waste safe for use as road construction aggregates or other fill materials. This paper will describe the results of start-up of a 1 ton-per-hour Plasma Mobile Asbestos Vitrification (MAV) Plant at a DOD Site in Port Clinton, Ohio. The Plasma MAV Plant is being demonstrated for the on-site disposal of 1.5 million pounds of Amosite asbestos fibers.« less

Building electronic data infrastructure for comparative effectiveness research: accomplishments, lessons learned and future steps.

PubMed

Randhawa, Gurvaneet S

2014-11-01

There are large gaps in our knowledge on the potential impact of diagnostics and therapeutics on outcomes of patients treated in the real world. Comparative effectiveness research aims to fill these gaps to maximize effectiveness of these interventions. Health information technology has the potential to dramatically improve the practice of medicine and of research. This is an overview of about US$100 million of American Recovery and Reinvestment Act investment in 12 projects managed by the Agency for Healthcare Research and Quality to build an electronic clinical data infrastructure that connects research with healthcare delivery. The achievements and lessons learned from these projects provided a foundation for the National Patient-Centered Clinical Research Network (PCORnet)and will help to guide future infrastructure development needed to build an efficient, scalable and sustainable learning health system.

The polymorphisms of the chromatin fiber

NASA Astrophysics Data System (ADS)

Boulé, Jean-Baptiste; Mozziconacci, Julien; Lavelle, Christophe

2015-01-01

In eukaryotes, the genome is packed into chromosomes, each consisting of large polymeric fibers made of DNA bound with proteins (mainly histones) and RNA molecules. The nature and precise 3D organization of this fiber has been a matter of intense speculations and debates. In the emerging picture, the local chromatin state plays a critical role in all fundamental DNA transactions, such as transcriptional control, DNA replication or repair. However, the molecular and structural mechanisms involved remain elusive. The purpose of this review is to give an overview of the tremendous efforts that have been made for almost 40 years to build physiologically relevant models of chromatin structure. The motivation behind building such models was to shift our representation and understanding of DNA transactions from a too simplistic ‘naked DNA’ view to a more realistic ‘coated DNA’ view, as a step towards a better framework in which to interpret mechanistically the control of genetic expression and other DNA metabolic processes. The field has evolved from a speculative point of view towards in vitro biochemistry and in silico modeling, but is still longing for experimental in vivo validations of the proposed structures or even proof of concept experiments demonstrating a clear role of a given structure in a metabolic transaction. The mere existence of a chromatin fiber as a relevant biological entity in vivo has been put into serious questioning. Current research is suggesting a possible reconciliation between theoretical studies and experiments, pointing towards a view where the polymorphic and dynamic nature of the chromatin fiber is essential to support its function in genome metabolism.

Gap junction- and hemichannel-independent actions of connexins.

PubMed

Jiang, Jean X; Gu, Sumin

2005-06-10

Connexins have been known to be the protein building blocks of gap junctions and mediate cell-cell communication. In contrast to the conventional dogma, recent evidence suggests that in addition to forming gap junction channels, connexins possess gap junction-independent functions. One important gap junction-independent function for connexins is to serve as the major functional component for hemichannels, the un-apposed halves of gap junctions. Hemichannels, as independent functional units, play roles that are different from that of gap junctions in the cell. The other functions of connexins appear to be gap junction- and hemichannel-independent. Published studies implicate the latter functions of connexins in cell growth, differentiation, tumorigenicity, injury, and apoptosis, although the mechanistic aspects of these actions remain largely unknown. In this review, gap junction- and hemichannel-independent functions of connexins are summarized, and the molecular mechanisms underlying these connexin functions are speculated and discussed.

Investigating the Gap Between Estimated and Actual Energy Efficiency and Conservation Savings for Public Buildings Projects & Programs in United States

NASA Astrophysics Data System (ADS)

Qaddus, Muhammad Kamil

The gap between estimated and actual savings in energy efficiency and conservation (EE&C) projects or programs forms the problem statement for the scope of public and government buildings. This gap has been analyzed first on impact and then on process-level. On the impact-level, the methodology leads to categorization of the gap as 'Realization Gap'. It then views the categorization of gap within the context of past and current narratives linked to realization gap. On process-level, the methodology leads to further analysis of realization gap on process evaluation basis. The process evaluation criterion, a product of this basis is then applied to two different programs (DESEU and NYC ACE) linked to the scope of this thesis. Utilizing the synergies of impact and process level analysis, it offers proposals on program development and its structure using our process evaluation criterion. Innovative financing and benefits distribution structure is thus developed and will remain part of the proposal. Restricted Stakeholder Crowd Financing and Risk-Free Incentivized return are the products of proposed financing and benefit distribution structure respectively. These products are then complimented by proposing an alternative approach in estimating EE&C savings. The approach advocates estimation based on range-allocation rather than currently utilized unique estimated savings approach. The Way Ahead section thus explores synergy between financial and engineering ranges of energy savings as a multi-discipline approach for future research. Moreover, it provides the proposed program structure with risk aversion and incentive allocation while dealing with uncertainty. This set of new approaches are believed to better fill the realization gap between estimated and actual energy efficiency savings.

Automated Fabrication Technologies for High Performance Polymer Composites

NASA Technical Reports Server (NTRS)

Shuart , M. J.; Johnston, N. J.; Dexter, H. B.; Marchello, J. M.; Grenoble, R. W.

1998-01-01

New fabrication technologies are being exploited for building high graphite-fiber-reinforced composite structure. Stitched fiber preforms and resin film infusion have been successfully demonstrated for large, composite wing structures. Other automatic processes being developed include automated placement of tacky, drapable epoxy towpreg, automated heated head placement of consolidated ribbon/tape, and vacuum-assisted resin transfer molding. These methods have the potential to yield low cost high performance structures by fabricating composite structures to net shape out-of-autoclave.

802.11ac WLAN MIMO radio-over-fiber distributed antenna system for in-building networks based on multicore fiber

NASA Astrophysics Data System (ADS)

Morant, Maria; Llorente, Roberto

2017-01-01

In this work we propose and evaluate experimentally the performance of IEEE 802.11ac WLAN standard signals in radio-over-fiber (RoF) distributed-antenna systems based on multicore fiber (MCF) for in-building WLAN connectivity. The RoF performance of WLAN signals with different bandwidth is investigated considering up to IEEE 802.11ac maximum of 160 MHz per user. We evaluate experimentally the performance of WLAN signals employing different modulation and coding schemes achieving bitrates from 78 Mbps to 1404 Mbps per user in distances up to 300 m in a 4-core MCF. The performance of the wireless standard multiple-input multiple-output (MIMO) processing algorithms included in WLAN signals applied to the RoF transmission in MCF optical systems is also evaluated. The impact on the quality of the signal from one of the cores in the MIMO processing is investigated and compared with the results achieved with single-input single-output (SISO) transmission in each core. We measured the error vector magnitude (EVM) and the OFDM data burst information of the received WLAN signals after RoF transmission for different distributed-antenna systems with uni- and bi-directional MCF communication. Finally, we compare the received EVM of a single-antenna system (SISO arrangement) with WLAN systems using two antennas (2×2 MIMO) and four antennas (4×4 MIMO).

Capacity-Building in Open Education: An Australian Approach

ERIC Educational Resources Information Center

Bossu, Carina; Fountain, Wendy

2015-01-01

Addressing the gap between global open educational resource (OER) proliferation and the slow adoption of OER and open educational practices (OEP) in Australian higher education, this paper focuses on a capacity-building project targeting academics, academic support staff and educational developers. The conception, design, development, piloting and…

Evidence for Altered Ca2+ Handling in Growth Associated Protein 43-Knockout Skeletal Muscle

PubMed Central

Caprara, Giusy A.; Morabito, Caterina; Perni, Stefano; Navarra, Riccardo; Guarnieri, Simone; Mariggiò, Maria A.

2016-01-01

Neuronal growth-associated protein 43 (GAP43) has crucial roles in the nervous system, and during development, regeneration after injury, and learning and memory. GAP43 is expressed in mouse skeletal muscle fibers and satellite cells, with suggested its involvement in intracellular Ca2+ handling. However, the physiological role of GAP43 in muscle remains unknown. Using a GAP43-knockout (GAP43−/−) mouse, we have defined the role of GAP43 in skeletal muscle. GAP43−/− mice showed low survival beyond weaning, reduced adult body weight, decreased muscle strength, and changed myofiber ultrastructure, with no significant differences in the expression of markers of satellite cell and myotube progression through the myogenic program. Thus, GAP43 expression is involved in timing of muscle maturation in-vivo. Intracellular Ca2+ measurements in-vitro in myotubes revealed GAP43 involvement in Ca2+ handling. In the absence of GAP43 expression, the spontaneous Ca2+ variations had greater amplitudes and higher frequency. In GAP43−/− myotubes, also the intracellular Ca2+ variations induced by the activation of dihydropyridine and ryanodine Ca2+ channels, resulted modified. These evidences suggested dysregulation of Ca2+ homeostasis. The emerging hypothesis indicates that GAP43 interacts with calmodulin to indirectly modulate the activities of dihydropyridine and ryanodine Ca2+ channels. This thus influences intracellular Ca2+ dynamics and its related intracellular patterns, from functional excitation-contraction coupling, to cell metabolism, and gene expression. PMID:27833566

Building America FY 2016 Annual Report: Building America Is Driving Real Solutions in the Race to Zero Energy Homes

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

Farrar, Sara; Rothgeb, Stacey; Polly, Ben

The U.S. Department of Energy (DOE) Building America Program enables the transformation of the U.S. housing industry to achieve energy savings through energy-efficient, high-performance homes with improved durability, comfort, and health for occupants. Building America bridges the gap between the development of emerging technologies and the adoption of codes and standards by engaging industry partners in applied research, development, and demonstration of high-performance solutions.

Educating Moral Emotions or Moral Selves: A False Dichotomy?

ERIC Educational Resources Information Center

Kristjansson, Kristjan

2010-01-01

In the post-Kohlbergian era of moral education, a "moral gap" has been identified between moral cognition and moral action. Contemporary moral psychologists lock horns over how this gap might be bridged. The two main contenders for such bridge-building are moral emotions and moral selves. I explore these two options from an Aristotelian…

Toward A Theory of HRD Learning Participation

ERIC Educational Resources Information Center

Wang, Greg G.; Wang, Jia

2005-01-01

This article fills a gap by identifying an under-studied area for learning participation (LP) in HRD theory building. A literature review is presented to identify gaps in adult education and HRD literature. An HRD LP framework is then proposed, from cross-sectional/time-series perspectives, to describe the pattern, factors, structure, and the…

Singling Black Boys to Close the Gaps

ERIC Educational Resources Information Center

Glassman, Phyllis; Roelle, Robert J.

2007-01-01

This article discusses the Ossining Union Free School District in suburban Westchester County, New York and its efforts to build successful school experiences for its black and African-American males. The leadership in the Ossining School District has made it a "moral imperative" to eradicate the achievement gap between the races in its…

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.

Multi-wavelength Praseodymium fiber laser using stimulated Brillouin scattering

NASA Astrophysics Data System (ADS)

Ahmad, H.; Aidit, S. N.; Tiu, Z. C.

2018-02-01

A multi-wavelength Brillouin Praseodymium fiber laser (MWBPFL) operating at 1300 nm region is demonstrated based on the hybrid scheme by utilizing Brillouin gain medium and Praseodymium-doped fluoride fiber as linear gain medium. A 15 μm air gap is incorporated into the cavity to allow the switching of Brillouin frequency spacing from double to single spacing. Under the Brillouin pump of 8 dBm and the 1020 nm pump power of 567.2 mW, 36 Stokes lines with a wavelength spacing of 0.16 nm and 24 Stokes lines with a wavelength spacing of 0.08 nm are achieved. The wavelength tunability of 8 nm is realized for both MWBPFLs by shifting the Brillouin pump wavelength. The MWBPFLs exhibit an excellent stability in the number of generated Stokes and power level over one-hour period.

Tapered optical fiber tip probes based on focused ion beam-milled Fabry-Perot microcavities

NASA Astrophysics Data System (ADS)

André, Ricardo M.; Warren-Smith, Stephen C.; Becker, Martin; Dellith, Jan; Rothhardt, Manfred; Zibaii, M. I.; Latifi, H.; Marques, Manuel B.; Bartelt, Hartmut; Frazão, Orlando

2016-09-01

Focused ion beam technology is combined with dynamic chemical etching to create microcavities in tapered optical fiber tips, resulting in fiber probes for temperature and refractive index sensing. Dynamic chemical etching uses hydrofluoric acid and a syringe pump to etch standard optical fibers into cone structures called tapered fiber tips where the length, shape, and cone angle can be precisely controlled. On these tips, focused ion beam is used to mill several different types of Fabry-Perot microcavities. Two main cavity types are initially compared and then combined to form a third, complex cavity structure. In the first case, a gap is milled on the tapered fiber tip which allows the external medium to penetrate the light guiding region and thus presents sensitivity to external refractive index changes. In the second, two slots that function as mirrors are milled on the tip creating a silica cavity that is only sensitive to temperature changes. Finally, both cavities are combined on a single tapered fiber tip, resulting in a multi-cavity structure capable of discriminating between temperature and refractive index variations. This dual characterization is performed with the aid of a fast Fourier transform method to separate the contributions of each cavity and thus of temperature and refractive index. Ultimately, a tapered optical fiber tip probe with sub-standard dimensions containing a multi-cavity structure is projected, fabricated, characterized and applied as a sensing element for simultaneous temperature and refractive index discrimination.

Interior. Distillation apparatus used for extracting small test amounts of ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Interior. Distillation apparatus used for extracting small test amounts of latex from plant fiber. - Thomas A. Edison Laboratories, Building No. 2, Main Street & Lakeside Avenue, West Orange, Essex County, NJ

Role of Mutagenicity in Asbestos Fiber-Induced Carcinogenicity and Other Diseases

PubMed Central

Huang, Sarah X. L.; Jaurand, Marie-Claude; Kamp, David W.; Whysner, John; Hei, Tom K.

2011-01-01

The cellular and molecular mechanisms of how asbestos fibers induce cancers and other diseases are not well understood. Both serpentine and amphibole asbestos fibers have been shown to induce oxidative stress, inflammatory responses, cellular toxicity and tissue injuries, genetic changes, and epigenetic alterations in target cells in vitro and tissues in vivo. Most of these mechanisms are believe to be shared by both fiber-induced cancers and noncancerous diseases. This article summarizes the findings from existing literature with a focus on genetic changes, specifically, mutagenicity of asbestos fibers. Thus far, experimental evidence suggesting the involvement of mutagenesis in asbestos carcinogenicity is more convincing than asbestos-induced fibrotic diseases. The potential contributions of mutagenicity to asbestos-induced diseases, with an emphasis on carcinogenicity, are reviewed from five aspects: (1) whether there is a mutagenic mode of action (MOA) in fiber-induced carcinogenesis; (2) mutagenicity/carcinogenicity at low dose; (3) biological activities that contribute to mutagenicity and impact of target tissue/cell type; (4) health endpoints with or without mutagenicity as a key event; and finally, (5) determinant factors of toxicity in mutagenicity. At the end of this review, a consensus statement of what is known, what is believed to be factual but requires confirmation, and existing data gaps, as well as future research needs and directions, is provided. PMID:21534089

Mathematical modeling and fluorescence imaging to study the Ca2+ turnover in skinned muscle fibers.

PubMed Central

Uttenweiler, D; Weber, C; Fink, R H

1998-01-01

A mathematical model was developed for the simulation of the spatial and temporal time course of Ca2+ ion movement in caffeine-induced calcium transients of chemically skinned muscle fiber preparations. Our model assumes cylindrical symmetry and quantifies the radial profile of Ca2+ ion concentration by solving the diffusion equations for Ca2+ ions and various mobile buffers, and the rate equations for Ca2+ buffering (mobile and immobile buffers) and for the release and reuptake of Ca2+ ions by the sarcoplasmic reticulum (SR), with a finite-difference algorithm. The results of the model are compared with caffeine-induced spatial Ca2+ transients obtained from saponin skinned murine fast-twitch fibers by fluorescence photometry and imaging measurements using the ratiometric dye Fura-2. The combination of mathematical modeling and digital image analysis provides a tool for the quantitative description of the total Ca2+ turnover and the different contributions of all interacting processes to the overall Ca2+ transient in skinned muscle fibers. It should thereby strongly improve the usage of skinned fibers as quantitative assay systems for many parameters of the SR and the contractile apparatus helping also to bridge the gap to the intact muscle fiber. PMID:9545029

Desalination by Membrane Distillation using Electrospun Polyamide Fiber Membranes with Surface Fluorination by Chemical Vapor Deposition.

PubMed

Guo, Fei; Servi, Amelia; Liu, Andong; Gleason, Karen K; Rutledge, Gregory C

2015-04-22

Fibrous membranes of poly(trimethyl hexamethylene terephthalamide) (PA6(3)T) were fabricated by electrospinning and rendered hydrophobic by applying a conformal coating of poly(1H,1H,2H,2H-perfluorodecyl acrylate) (PPFDA) using initiated chemical vapor deposition (iCVD). A set of iCVD-treated electrospun PA6(3)T fiber membranes with fiber diameters ranging from 0.25 to 1.8 μm were tested for desalination using the air gap membrane distillation configuration. Permeate fluxes of 2-11 kg/m2/h were observed for temperature differentials of 20-45 °C between the feed stream and condenser plate, with rejections in excess of 99.98%. The liquid entry pressure was observed to increase dramatically, from 15 to 373 kPa with reduction in fiber diameter. Contrary to expectation, for a given feed temperature the permeate flux was observed to increase for membranes of decreasing fiber diameter. The results for permeate flux and salt rejection show that it is possible to construct membranes for membrane distillation even from intrinsically hydrophilic materials after surface modification by iCVD and that the fiber diameter is shown to play an important role on the membrane distillation performance in terms of permeate flux, salt rejection, and liquid entry pressure.

Finite element modeling of the cyclic wetting mechanism in the active part of wheat awns.

PubMed

Zickler, Gerald A; Ruffoni, Davide; Dunlop, John W C; Elbaum, Rivka; Weinkamer, Richard; Fratzl, Peter; Antretter, Thomas

2012-12-01

Many plant tissues and organs are capable of moving due to changes in the humidity of the environment, such as the opening of the seed capsule of the ice plant and the opening of the pine cone. These are fascinating examples for the materials engineer, as these tissues are non-living and move solely through the differential swelling of anisotropic tissues and in principle may serve as examples for the bio-inspired design of artificial actuators. In this paper, we model the microstructure of the wild wheat awn (Triticum turgidum ssp. dicoccoides) by finite elements, especially focusing on the specific microscopic features of the active part of the awn. Based on earlier experimental findings, cell walls are modeled as multilayered cylindrical tubes with alternating cellulose fiber orientation in successive layers. It is shown that swelling upon hydration of this system leads to the formation of gaps between the layers, which could act as valves, thus enabling the entry of water into the cell wall. This supports the hypothesis that this plywood-like arrangement of cellulose fibrils enhances the effect of ambient humidity by accelerated water or vapor diffusion along the gaps. The finite element model shows that a certain distribution of axially and tangentially oriented fibers is necessary to generate sufficient tensile stresses within the cell wall to open nanometer-sized gaps between cell wall layers.

The Myosin IXb Motor Activity Targets the Myosin IXb RhoGAP Domain as Cargo to Sites of Actin Polymerization

PubMed Central

van den Boom, Frank; Düssmann, Heiko; Uhlenbrock, Katharina; Abouhamed, Marouan

2007-01-01

Myosin IXb (Myo9b) is a single-headed processive myosin that exhibits Rho GTPase-activating protein (RhoGAP) activity in its tail region. Using live cell imaging, we determined that Myo9b is recruited to extending lamellipodia, ruffles, and filopodia, the regions of active actin polymerization. A functional motor domain was both necessary and sufficient for targeting Myo9b to these regions. The head domains of class IX myosins comprise a large insertion in loop2. Deletion of the large Myo9b head loop 2 insertion abrogated the enrichment in extending lamellipodia and ruffles, but enhanced significantly the enrichment at the tips of filopodia and retraction fibers. The enrichment in the tips of filopodia and retraction fibers depended on four lysine residues C-terminal to the loop 2 insertion and the tail region. Fluorescence recovery after photobleaching and photoactivation experiments in lamellipodia revealed that the dynamics of Myo9b was comparable to that of actin. The exchange rates depended on the Myo9b motor region and motor activity, and they were also dependent on the turnover of F-actin. These results demonstrate that Myo9b functions as a motorized RhoGAP molecule in regions of actin polymerization and identify Myo9b head sequences important for in vivo motor properties. PMID:17314409

Nervous System of Periplaneta americana Cockroach as a Model in Toxinological Studies: A Short Historical and Actual View

PubMed Central

Stankiewicz, Maria; Dąbrowski, Marcin; de Lima, Maria Elena

2012-01-01

Nervous system of Periplaneta americana cockroach is used in a wide range of pharmacological studies, including electrophysiological techniques. This paper presents its role as a preparation in the development of toxinological studies in the following electrophysiological methods: double-oil-gap technique on isolated giant axon, patch-clamp on DUM (dorsal unpaired median) neurons, microelectrode technique in situ conditions on axon in connective and DUM neurons in ganglion, and single-fiber oil-gap technique on last abdominal ganglion synapse. At the end the application of cockroach synaptosomal preparation is mentioned. PMID:22666245

Formulation and characterization of date palm fibers mortar by addition of silica fume

NASA Astrophysics Data System (ADS)

Mokhtari, A.; Kriker, A.; Ouaggad, H.; Merad, N.

2018-05-01

This paper presents the results of experimental investigations of the formulated and characterization of date palm fibers mortar by addition of silica fume. The use of addition mineral is widely used in the production of cements through the world. The objective of this work is to bring our contribution to the recovery of local resources in the occurrence vegetable fibers of date palm to weak cost and from renewable source and integrate it in the filled of building. Date palm fiber are from Ouargla town in south of Algeria. Different mortar mixtures were prepared in which the cement was substitute by 10% of silica fume. The mechanical characteristics (compressive and flexural strength) of date palm fibers mortar by treatment of the matrix by the adding of silica fume were examined. The results obtained have shown that the mortar workability as well as the compressive and flexural strength decreases with increasing the silica fume replacement. The results showed that the use of silica fume enabled to evaluate the flexural strength. However, another treatment of fibers and matrix will be recommended for Improved the characteristics.

Integrating quantum key distribution with classical communications in backbone fiber network.

PubMed

Mao, Yingqiu; Wang, Bi-Xiao; Zhao, Chunxu; Wang, Guangquan; Wang, Ruichun; Wang, Honghai; Zhou, Fei; Nie, Jimin; Chen, Qing; Zhao, Yong; Zhang, Qiang; Zhang, Jun; Chen, Teng-Yun; Pan, Jian-Wei

2018-03-05

Quantum key distribution (QKD) provides information-theoretic security based on the laws of quantum mechanics. The desire to reduce costs and increase robustness in real-world applications has motivated the study of coexistence between QKD and intense classical data traffic in a single fiber. Previous works on coexistence in metropolitan areas have used wavelength-division multiplexing, however, coexistence in backbone fiber networks remains a great experimental challenge, as Tbps data of up to 20 dBm optical power is transferred, and much more noise is generated for QKD. Here we present for the first time, to the best of our knowledge, the integration of QKD with a commercial backbone network of 3.6 Tbps classical data at 21 dBm launch power over 66 km fiber. With 20 GHz pass-band filtering and large effective core area fibers, real-time secure key rates can reach 4.5 kbps and 5.1 kbps for co-propagation and counter-propagation at the maximum launch power, respectively. This demonstrates feasibility and represents an important step towards building a quantum network that coexists with the current backbone fiber infrastructure of classical communications.

Study of the mechanical properties of Ziziphus nummularia (ber) fibers for formation of fiber reinforced composites

NASA Astrophysics Data System (ADS)

Joshi, Akshay; Mangal, R.; Bhojak, N.

2018-05-01

Ziziphus is the one of the most abundant plant of arid region of Rajasthan and rest part of desert land in world. There are a lots of research work going on and has been done on medical applications of this plant and it is playing very important role in economy of desert areas. In this paper our discussion will bring the attention its physical properties so that we can find the possibility of its applications in the various field of fiber reinforced composites which either can be used in such as interior & exterior part of automotive so it can reduce their overall weight, cost and improve its fuel efficiency without compromising in strength or can be used in flywheel technology for energy saving in automobiles or in building materials and so on. In this paper our approach is to extract the fiber from this plant, analyze the mechanical properties of the fiber and then discuss the various possibility of its application in appropriate field of composites. To find the possibility in FRC for Ziziphus fiber our next step is to compare it with other fibers whose composites have already been formed and studied.

UNC-Utah NA-MIC framework for DTI fiber tract analysis.

PubMed

Verde, Audrey R; Budin, Francois; Berger, Jean-Baptiste; Gupta, Aditya; Farzinfar, Mahshid; Kaiser, Adrien; Ahn, Mihye; Johnson, Hans; Matsui, Joy; Hazlett, Heather C; Sharma, Anuja; Goodlett, Casey; Shi, Yundi; Gouttard, Sylvain; Vachet, Clement; Piven, Joseph; Zhu, Hongtu; Gerig, Guido; Styner, Martin

2014-01-01

Diffusion tensor imaging has become an important modality in the field of neuroimaging to capture changes in micro-organization and to assess white matter integrity or development. While there exists a number of tractography toolsets, these usually lack tools for preprocessing or to analyze diffusion properties along the fiber tracts. Currently, the field is in critical need of a coherent end-to-end toolset for performing an along-fiber tract analysis, accessible to non-technical neuroimaging researchers. The UNC-Utah NA-MIC DTI framework represents a coherent, open source, end-to-end toolset for atlas fiber tract based DTI analysis encompassing DICOM data conversion, quality control, atlas building, fiber tractography, fiber parameterization, and statistical analysis of diffusion properties. Most steps utilize graphical user interfaces (GUI) to simplify interaction and provide an extensive DTI analysis framework for non-technical researchers/investigators. We illustrate the use of our framework on a small sample, cross sectional neuroimaging study of eight healthy 1-year-old children from the Infant Brain Imaging Study (IBIS) Network. In this limited test study, we illustrate the power of our method by quantifying the diffusion properties at 1 year of age on the genu and splenium fiber tracts.

UNC-Utah NA-MIC framework for DTI fiber tract analysis

PubMed Central

Verde, Audrey R.; Budin, Francois; Berger, Jean-Baptiste; Gupta, Aditya; Farzinfar, Mahshid; Kaiser, Adrien; Ahn, Mihye; Johnson, Hans; Matsui, Joy; Hazlett, Heather C.; Sharma, Anuja; Goodlett, Casey; Shi, Yundi; Gouttard, Sylvain; Vachet, Clement; Piven, Joseph; Zhu, Hongtu; Gerig, Guido; Styner, Martin

2014-01-01

Diffusion tensor imaging has become an important modality in the field of neuroimaging to capture changes in micro-organization and to assess white matter integrity or development. While there exists a number of tractography toolsets, these usually lack tools for preprocessing or to analyze diffusion properties along the fiber tracts. Currently, the field is in critical need of a coherent end-to-end toolset for performing an along-fiber tract analysis, accessible to non-technical neuroimaging researchers. The UNC-Utah NA-MIC DTI framework represents a coherent, open source, end-to-end toolset for atlas fiber tract based DTI analysis encompassing DICOM data conversion, quality control, atlas building, fiber tractography, fiber parameterization, and statistical analysis of diffusion properties. Most steps utilize graphical user interfaces (GUI) to simplify interaction and provide an extensive DTI analysis framework for non-technical researchers/investigators. We illustrate the use of our framework on a small sample, cross sectional neuroimaging study of eight healthy 1-year-old children from the Infant Brain Imaging Study (IBIS) Network. In this limited test study, we illustrate the power of our method by quantifying the diffusion properties at 1 year of age on the genu and splenium fiber tracts. PMID:24409141

Batako Quality Optimization with Addition of Palm Oil Stem Fiber from Kampar District and Dumai City

NASA Astrophysics Data System (ADS)

Zainuri; Yanti, Gusneli; Wahyuni Megasari, Shanti

2017-12-01

The waste of dry palm oil produced by 148 trees per hectare is 3,108 ton/month or 37,296 ton/year as calculated. Riau province has oil palm plantations covering an area of 2.399.172 hectares (BPS Riau Province, 2014). It can be estimated the amount of waste generated. Palm stem waste can be utilized, one of which is the utilization of midrib fiber as an added material in the manufacture of batako. Batako- fiber that is made still must be examined feasibility as building materials. The purpose of this study was to determine the optimization of the quality of batako works by the addition of palm stem fiber originated from the districts of Kampar and Dumai. This research used experimental method with laboratory research. Batako-fiber with the addition of palm fiber stem 1% of the weight of cement can increase the value of compressive strength above the normal batako and a batako with first quality according to SNI 03-0349-1989 standard. The use of palm stem fiber originating from the Kampar district resulted in better batakos with higher average compressive strength values than the dumai-derived fibers, especially in the addition of 1% fiber by weight of cement. The finding of this research is that the batakos originating from Kampar district are better than those from Dumai city. The most optimal addition of palm fiber burrs to batako-fiber products is 1% of the weight of cement.

Developing health information literacy: a needs analysis from the perspective of preprofessional health students*

PubMed Central

Ivanitskaya, Lana V.; Hanisko, Kaitlyn A.; Garrison, Julie A.; Janson, Samantha J.; Vibbert, Danielle

2012-01-01

Objective: The research identified the skills, if any, that health preprofessional students wished to develop after receiving feedback on skill gaps as well as any strategies they intended to use to address these gaps. Methods: A qualitative approach was used to elicit students' reflections on building health information literacy skills. First, the students took the Research Readiness Self-Assessment instrument, which measured their health information literacy, and then they received individually tailored feedback about their scores and skill gaps. Second, students completed a post-assessment survey asking how they intended to close identified gaps in their skills on these. Three trained coders analyzed qualitative comments by 181 students and grouped them into themes relating to “what skills to improve” and “how to improve them.” Results: Students intended to develop library skills (64% of respondents), Internet skills (63%), and information evaluation skills (63%). Most students reported that they would use library staff members' assistance (55%), but even more respondents (82%) planned to learn the skills by practicing on their own. Getting help from librarians was a much more popular learning strategy than getting assistance from peers (20%) or professors (17%). Conclusions: The study highlighted the importance of providing health preprofessional students with resources to improve skills on their own, remote access to library staff members, and instruction on the complexity of building health literacy skills, while also building relationships among students, librarians, and faculty. PMID:23133327

Photoemission and energy gap of MgWO4 particles connecting as nanofibers synthesized by electrospinning-calcination combinations

NASA Astrophysics Data System (ADS)

Wannapop, Surangkana; Thongtem, Titipun; Thongtem, Somchai

2012-03-01

Mixtures of magnesium acetate tetrahydrate ((CH3COO)2Mg·4H2O), ammonium tungstate tetrahydrate ((NH4)6W7O24·4H2O), and poly(vinyl alcohol) with the molecular weight of 72,000 were electrospun through a +15 kV direct voltage to form fibers on ground flat aluminum foils. The electrospun fibers of 1.5, 3.0, and 4.5 mmol of each starting material containing 1.3 g poly(vinyl alcohol) were further calcined at 500-700 °C for 3 h constant length of time. At 500 and 600 °C calcination, both monoclinic and anorthic phases of MgWO4 particles with different sizes connecting as fibrous assemblies were detected. Upon increasing the calcination temperature to 700 °C, only monoclinic phase of facet nanoparticles interconnecting along the fibrous axes with 4.19 eV indirect band gap and 461 nm photoemission was synthesized. In the present research, formation of MgWO4 molecules as well as nucleation and growth of nanoparticles was also proposed.

Basalt fiber insulating material with a mineral binding agent for industrial use

NASA Astrophysics Data System (ADS)

Drozdyuk, T.; Aizenshtadt, A.; Tutygin, A.; Frolova, M.

2016-04-01

The paper considers a possibility of using mining industry waste as a binding agent for heat insulating material on the basis of basalt fiber. The main objective of the research is to produce a heat-insulating material to be applied in machine building in high-temperature environments. After synthetic binder having been replaced by a mineral one, an environmentally sound thermal insulating material having desirable heat-protecting ability and not failing when exposed to high temperatures was obtained.

E-beam-Cure Fabrication of Polymer Fiber/Matrix Composites for Multifunctional Radiation Shielding

NASA Technical Reports Server (NTRS)

Wilson, John W.; Jensen, Brian J.; Thibeault, Sheila A.; Hou, Tan-Hung; Saether, Erik; Glaessgen, Edward H.; Humes, Donald H.; Chang, Chie K.; Badavi, Francis F.; Kiefer, Rrichard L.;

Manhattan Solar Cannon

NASA Astrophysics Data System (ADS)

Treffers, Richard R.; Loisos, George; Ubbelohde, Susan; Douglas, Susanna; Pintos, Eduardo; Mulherin, James; Pasley, David

2015-01-01

We describe a 2.4 m hexagonal solar collector atop a Manhattan office building used for a solar / arts project. The collector uses an afocal design to concentrate the sunlight into a 0.6 m diameter beam which is directed by mirrors into a 80 m long fiber optic sculpture which descends an interior stairwell. The collector is fully steerable and follows the sun each day robotically. The control system and the optical design of the collector as well as the fiber optic sculpture will be discussed.

Merging building maintainability and sustainability assessment: A multicriteria decision making approach

NASA Astrophysics Data System (ADS)

Asmone, A. S.; Chew, M. Y. L.

2018-02-01

Accurately predicting maintainability has been a challenge due to the complex nature of buildings, yet it is an important research area with a rising necessity. This paper explores the use of multicriteria decision making approach for merging maintainability and sustainability elements into building grading systems to attain long-term sustainability in the building industry. The paper conducts a systematic literature review on multicriteria decision analysis approach and builds on the existing knowledge of maintainability to achieve this. A conceptual framework is developed to bridge the gap between building operations and maintenance with green facilities management by forecasting green maintainability at the design stage.

Robustness effect of gap junctions between Golgi cells on cerebellar cortex oscillations

PubMed Central

2011-01-01

Background Previous one-dimensional network modeling of the cerebellar granular layer has been successfully linked with a range of cerebellar cortex oscillations observed in vivo. However, the recent discovery of gap junctions between Golgi cells (GoCs), which may cause oscillations by themselves, has raised the question of how gap-junction coupling affects GoC and granular-layer oscillations. To investigate this question, we developed a novel two-dimensional computational model of the GoC-granule cell (GC) circuit with and without gap junctions between GoCs. Results Isolated GoCs coupled by gap junctions had a strong tendency to generate spontaneous oscillations without affecting their mean firing frequencies in response to distributed mossy fiber input. Conversely, when GoCs were synaptically connected in the granular layer, gap junctions increased the power of the oscillations, but the oscillations were primarily driven by the synaptic feedback loop between GoCs and GCs, and the gap junctions did not change oscillation frequency or the mean firing rate of either GoCs or GCs. Conclusion Our modeling results suggest that gap junctions between GoCs increase the robustness of cerebellar cortex oscillations that are primarily driven by the feedback loop between GoCs and GCs. The robustness effect of gap junctions on synaptically driven oscillations observed in our model may be a general mechanism, also present in other regions of the brain. PMID:22330240

Towards the use of bioresorbable fibers in time-domain diffuse optics.

PubMed

Di Sieno, Laura; Boetti, Nadia G; Dalla Mora, Alberto; Pugliese, Diego; Farina, Andrea; Konugolu Venkata Sekar, Sanathana; Ceci-Ginistrelli, Edoardo; Janner, Davide; Pifferi, Antonio; Milanese, Daniel

2018-01-01

In the last years bioresorbable materials are gaining increasing interest for building implantable optical components for medical devices. In this work we show the fabrication of bioresorbable optical fibers designed for diffuse optics applications, featuring large core diameter (up to 200 μm) and numerical aperture (0.17) to maximize the collection efficiency of diffused light. We demonstrate the suitability of bioresorbable fibers for time-domain diffuse optical spectroscopy firstly checking the intrinsic performances of the setup by acquiring the instrument response function. We then validate on phantoms the use of bioresorbable fibers by applying the MEDPHOT protocol to assess the performance of the system in measuring optical properties (namely, absorption and scattering coefficients) of homogeneous media. Further, we show an ex-vivo validation on a chicken breast by measuring the absorption and scattering spectra in the 500-1100 nm range using interstitially inserted bioresorbable fibers. This work represents a step toward a new way to look inside the body using optical fibers that can be implanted in patients. These fibers could be useful either for diagnostic (e. g. for monitoring the evolution after surgical interventions) or treatment (e. g. photodynamic therapy) purposes. Picture: Microscopy image of the 100 μm core bioresorbable fiber. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fiber-based wearable electronics: a review of materials, fabrication, devices, and applications.

PubMed

Zeng, Wei; Shu, Lin; Li, Qiao; Chen, Song; Wang, Fei; Tao, Xiao-Ming

2014-08-20

Fiber-based structures are highly desirable for wearable electronics that are expected to be light-weight, long-lasting, flexible, and conformable. Many fibrous structures have been manufactured by well-established lost-effective textile processing technologies, normally at ambient conditions. The advancement of nanotechnology has made it feasible to build electronic devices directly on the surface or inside of single fibers, which have typical thickness of several to tens microns. However, imparting electronic functions to porous, highly deformable and three-dimensional fiber assemblies and maintaining them during wear represent great challenges from both views of fundamental understanding and practical implementation. This article attempts to critically review the current state-of-arts with respect to materials, fabrication techniques, and structural design of devices as well as applications of the fiber-based wearable electronic products. In addition, this review elaborates the performance requirements of the fiber-based wearable electronic products, especially regarding the correlation among materials, fiber/textile structures and electronic as well as mechanical functionalities of fiber-based electronic devices. Finally, discussions will be presented regarding to limitations of current materials, fabrication techniques, devices concerning manufacturability and performance as well as scientific understanding that must be improved prior to their wide adoption. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Shrinkage modeling of concrete reinforced by palm fibres in hot dry environments

NASA Astrophysics Data System (ADS)

Akchiche, Hamida; Kriker, Abdelouahed

2017-02-01

The cement materials, such as concrete and conventional mortar present very little resistance to traction and cracking, these hydraulic materials which induces large withdrawals on materials and cracks in structures. The hot dry environments such as: the Saharan regions of Algeria, Indeed, concrete structures in these regions are very fragile, and present high shrinkage. Strengthening of these materials by fibers can provide technical solutions for improving the mechanical performance. The aim of this study is firstly, to reduce the shrinkage of conventional concrete with its reinforcement with date palm fibers. In fact, Algeria has an extraordinary resources in natural fibers (from Palm, Abaca, Hemp) but without valorization in practical areas, especially in building materials. Secondly, to model the shrinkage behavior of concrete was reinforced by date palm fibers. In the literature, several models for still fiber concrete were founded but few are offers for natural fiber concretes. To do so, a still fiber concretes model of YOUNG - CHERN was used. According to the results, a reduction of shrinkage with reinforcement by date palm fibers was showed. A good ability of molding of shrinkage of date palm reinforced concrete with YOUNG - CHERN Modified model was obtained. In fact, a good correlation between experimental data and the model data was recorded.

Building and Testing a Superconductivity Measurement Platform for a Helium Cryostat

NASA Astrophysics Data System (ADS)

Rose, Heath; Ostrander, Joshua; Wu, Jim; Ramos, Roberto

2013-03-01

Superconductivity experiments using Josephson junctions are an excellent environment to study quantum mechanics and materials science. A standard electrical transport technique uses filtered four wire measurement of these superconducting devices. We report our experience as undergraduates in a liberal arts college in building and testing an experimental platform anchored on the cold-finger of a helium cryostat and designed for performing differential conductance measurements in Josephson junctions. To filter out RF, we design, build and test cryogenic filters using ceramic capacitors and inductors and thermocoax cables. We also use fixed attenuators for thermal anchoring and use miniature connectors to connect wires and coax to a sample box. We report on progress in our diagnostic measurements as well as low-temperature tunneling experiments to probe the structure of the energy gap in both single- and multi-gapped superconductors. We acknowledge the support of the National Science Foundation through NSF Grant DMR-1206561.

Research Networks, Mentorship and Sustainability Knowledge

NASA Astrophysics Data System (ADS)

Kafle, A.; Mukhopadhyay, P.; Nepal, M.; Shyamsundar, P.

2015-12-01

In South Asia, a majority of institutions are ill-equipped to undertake research on multi-disciplinary environmental problems, though these problems are increasing at a fast rate and connected to the region's poverty and growth objectives. In this context, the South Asian Network for Development and Environmental Economics (SANDEE) tries to fill a research, training and knowledge gap by building skills in the area of Environment and Development Economics. In this paper, the authors argue that research networks contribute to the growth of sustainability knowledge through (a) knowledge creation, (b) knowledge transfer and (c) knowledge deepening. The paper tries to show the relationship between capacity building, mentorship and research scholarship. It demonstrates that researchers, by associating with the network and its multiple training and mentoring processes, are able to build skills, change curricula and deliver useful knowledge products. The paper discusses the need for interdisciplinary research and the challenges of bridging the gap between research outputs and policy reforms.

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

Neural networks within multi-core optic fibers

PubMed Central

Cohen, Eyal; Malka, Dror; Shemer, Amir; Shahmoon, Asaf; Zalevsky, Zeev; London, Michael

2016-01-01

Hardware implementation of artificial neural networks facilitates real-time parallel processing of massive data sets. Optical neural networks offer low-volume 3D connectivity together with large bandwidth and minimal heat production in contrast to electronic implementation. Here, we present a conceptual design for in-fiber optical neural networks. Neurons and synapses are realized as individual silica cores in a multi-core fiber. Optical signals are transferred transversely between cores by means of optical coupling. Pump driven amplification in erbium-doped cores mimics synaptic interactions. We simulated three-layered feed-forward neural networks and explored their capabilities. Simulations suggest that networks can differentiate between given inputs depending on specific configurations of amplification; this implies classification and learning capabilities. Finally, we tested experimentally our basic neuronal elements using fibers, couplers, and amplifiers, and demonstrated that this configuration implements a neuron-like function. Therefore, devices similar to our proposed multi-core fiber could potentially serve as building blocks for future large-scale small-volume optical artificial neural networks. PMID:27383911

Neural networks within multi-core optic fibers.

PubMed

Cohen, Eyal; Malka, Dror; Shemer, Amir; Shahmoon, Asaf; Zalevsky, Zeev; London, Michael

2016-07-07

Hardware implementation of artificial neural networks facilitates real-time parallel processing of massive data sets. Optical neural networks offer low-volume 3D connectivity together with large bandwidth and minimal heat production in contrast to electronic implementation. Here, we present a conceptual design for in-fiber optical neural networks. Neurons and synapses are realized as individual silica cores in a multi-core fiber. Optical signals are transferred transversely between cores by means of optical coupling. Pump driven amplification in erbium-doped cores mimics synaptic interactions. We simulated three-layered feed-forward neural networks and explored their capabilities. Simulations suggest that networks can differentiate between given inputs depending on specific configurations of amplification; this implies classification and learning capabilities. Finally, we tested experimentally our basic neuronal elements using fibers, couplers, and amplifiers, and demonstrated that this configuration implements a neuron-like function. Therefore, devices similar to our proposed multi-core fiber could potentially serve as building blocks for future large-scale small-volume optical artificial neural networks.

Microflow1, a sheathless fiber-optic flow cytometry biomedical platform: demonstration onboard the international space station.

PubMed

Dubeau-Laramée, Geneviève; Rivière, Christophe; Jean, Isabelle; Mermut, Ozzy; Cohen, Luchino Y

2014-04-01

A fiber-optic based flow cytometry platform was designed to build a portable and robust instrument for space applications. At the core of the Microflow1 is a unique fiber-optic flow cell fitted to a fluidic system and fiber coupled to the source and detection channels. A Microflow1 engineering unit was first tested and benchmarked against a commercial flow cytometer as a reference in a standard laboratory environment. Testing in parabolic flight campaigns was performed to establish Microflow1's performance in weightlessness, before operating the new platform on the International Space Station. Microflow1 had comparable performances to commercial systems, and operated remarkably and robustly in weightlessness (microgravity). Microflow1 supported immunophenotyping as well as microbead-based multiplexed cytokine assays in the space environment and independently of gravity levels. Results presented here provide evidence that this fiber-optic cytometer technology is inherently compatible with the space environment with negligible compromise to analytical performance. © 2013 International Society for Advancement of Cytometry.

Building Energy Monitoring and Analysis

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

Hong, Tianzhen; Feng, Wei; Lu, Alison

This project aimed to develop a standard methodology for building energy data definition, collection, presentation, and analysis; apply the developed methods to a standardized energy monitoring platform, including hardware and software, to collect and analyze building energy use data; and compile offline statistical data and online real-time data in both countries for fully understanding the current status of building energy use. This helps decode the driving forces behind the discrepancy of building energy use between the two countries; identify gaps and deficiencies of current building energy monitoring, data collection, and analysis; and create knowledge and tools to collect and analyzemore » good building energy data to provide valuable and actionable information for key stakeholders.« less

A Self-Referenced Optical Intensity Sensor Network Using POFBGs for Biomedical Applications

PubMed Central

Moraleda, Alberto Tapetado; Montero, David Sánchez; Webb, David J.; García, Carmen Vázquez

2014-01-01

This work bridges the gap between the remote interrogation of multiple optical sensors and the advantages of using inherently biocompatible low-cost polymer optical fiber (POF)-based photonic sensing. A novel hybrid sensor network combining both silica fiber Bragg gratings (FBG) and polymer FBGs (POFBG) is analyzed. The topology is compatible with WDM networks so multiple remote sensors can be addressed providing high scalability. A central monitoring unit with virtual data processing is implemented, which could be remotely located up to units of km away. The feasibility of the proposed solution for potential medical environments and biomedical applications is shown. PMID:25615736

Experimental study on slow flexural waves around the defect modes in a phononic crystal beam using fiber Bragg gratings

NASA Astrophysics Data System (ADS)

Chuang, Kuo-Chih; Zhang, Zhi-Qiang; Wang, Hua-Xin

2016-12-01

This work experimentally studies influences of the point defect modes on the group velocity of flexural waves in a phononic crystal Timoshenko beam. Using the transfer matrix method with a supercell technique, the band structures and the group velocities around the defect modes are theoretically obtained. Particularly, to demonstrate the existence of the localized defect modes inside the band gaps, a high-sensitivity fiber Bragg grating sensing system is set up and the displacement transmittance is measured. Slow propagation of flexural waves via defect coupling in the phononic crystal beam is then experimentally demonstrated with Hanning windowed tone burst excitations.

A self-referenced optical intensity sensor network using POFBGs for biomedical applications.

PubMed

Tapetado Moraleda, Alberto; Sánchez Montero, David; Webb, David J; Vázquez García, Carmen

2014-12-12

This work bridges the gap between the remote interrogation of multiple optical sensors and the advantages of using inherently biocompatible low-cost polymer optical fiber (POF)-based photonic sensing. A novel hybrid sensor network combining both silica fiber Bragg gratings (FBG) and polymer FBGs (POFBG) is analyzed. The topology is compatible with WDM networks so multiple remote sensors can be addressed providing high scalability. A central monitoring unit with virtual data processing is implemented, which could be remotely located up to units of km away. The feasibility of the proposed solution for potential medical environments and biomedical applications is shown.

Investigation of fiber-reinforced self-consolidating concrete.

DOT National Transportation Integrated Search

2010-05-01

The rising cost of materials and labor, as well as the demand for faster construction, has prompted development of cheaper, faster alternatives to conventional building techniques. Self-consolidating concrete (SCC), a high performance concrete charac...

Guilty as Charged? Principals' Perspectives on Disciplinary Practices and the Racial Discipline Gap

ERIC Educational Resources Information Center

DeMatthews, David E.; Carey, Roderick L.; Olivarez, Arturo; Moussavi Saeedi, Kevin

2017-01-01

Background: For decades, Black students have been more likely to be suspended than their White peers despite any evidence suggesting they are more likely to misbehave. This research builds on critical race theory and social justice leadership to explore and contextualize leadership practice as it relates to the racial discipline gap. Purpose: The…

Preparing for Democracy: How Community-Based Organizations Build Civic Engagement among Urban Youth

ERIC Educational Resources Information Center

Shiller, Jessica T.

2013-01-01

The National Assessment of Education Progress (NAEP) shows a civic knowledge gap similar to the achievement gap, showing urban youth struggling in particular. However, research has shown that urban youth can be civically engaged when they are involved in projects or organizing intended to improve community conditions, not simply absorbing civic…

Building Capacity to Support Students with Autism Spectrum Disorder: A Modular Approach to Intervention

ERIC Educational Resources Information Center

Anderson, Cynthia M.; Smith, Tristram; Iovannone, Rose

2018-01-01

There is a large gap between research-based interventions for supporting children with autism spectrum disorder (ASD) and current practices implemented by educators to meet the needs of these children in typical school settings. Myriad reasons for this gap exist including the external validity of existing research, the complexity of ASD, and…

Building a Bridge to Span the Minority-Majority Achievement Gap.

ERIC Educational Resources Information Center

Lanasa, Philip J., III; Potter, Jane Hopkins

A number of hypotheses have been advanced to explain why black students lag behind whites in school achievement. In the 1950s and 1960s, an environmental hypothesis emerged which attributed the achievement gap to environment. Environmentalists at this point were divided between those who felt the family determined achievement and those who felt…

Unequally Safe: The Race Gap in School Safety. Working Paper #01-13

ERIC Educational Resources Information Center

Lacoe, Johanna

2013-01-01

Inequality in educational outcomes is a frequent topic of policy debate. This paper investigates one potential source of educational inequality--school safety. With panel survey data of middle school students, this paper estimates racial gaps in student feelings of safety in the classroom, in the hallways, and outside the school building, and how…

Why Race and Culture Matter in Schools: Closing the Achievement Gap in America's Classrooms. Multicultural Education Series

ERIC Educational Resources Information Center

Howard, Tyrone C.

2010-01-01

While race and culture remain important variables in how young people experience schools, they are often misunderstood by educators and school personnel. Building on the work of three studies that investigated schools successful in closing the achievement gap, Tyrone Howard shows how adopting greater awareness and comprehensive understanding of…

Increasing power and amplified spontaneous emission suppression for weak signal amplification in pulsed fiber amplifier

NASA Astrophysics Data System (ADS)

Luo, Yi; Zhang, Hanwei; Wang, Xiaolin; Su, Rongtao; Ma, Pengfei; Zhou, Pu; Jiang, Zongfu

2017-10-01

In the pulsed fiber amplifiers with repetition frequency of several tens kHz, amplified spontaneous emission (ASE) is easy to build up because of the low repetition frequency and weak pulse signal. The ASE rises the difficulty to amplify the weak pulse signal effectively. We have demonstrated an all-fiber preamplifier stage structure to amplify a 40 kHz, 10 ns bandwidth (FWHM) weak pulse signal (299 μW) with center wavelength of 1062 nm. Compared synchronous pulse pump with continuous wave(CW) pump, the results indicate that synchronous pulse pump shows the better capability of increasing the output power than CW pump. In the condition of the same pump power, the output power of synchronous pulse pump is twice as high as CW pump. In order to suppress ASE, a longer gain fiber is utilized to reabsorb the ASE in which the wavelength is shorter than 1062nm. We amplified weak pulse signal via 0.8 m and 2.1 m gain fiber in synchronous pulse pump experiments respectively, and more ASE in the output spectra are observed in the 0.8 m gain fiber system. Due to the weaker ASE and consequent capability of higher pump power, the 2.1 m gain fiber is capable to achieve higher output power than shorter fiber. The output power of 2.1 m gain fiber case is limited by pump power.

What Age Gap? Building Intergenerational Relationships

ERIC Educational Resources Information Center

Davidson, Stephanie R.; Boals-Gilbert, Beverly

2010-01-01

Few people are willing to admit that senior adults and young children share many common characteristics, including: (1) changes in development; (2) need for companionship; and (3) the desire to be understood. These two groups are connected mostly through direct interaction with middle-aged adults. One very practical way to build a greater sense of…

Building and Activating Students' Background Knowledge: It's What They Already Know That Counts

ERIC Educational Resources Information Center

Fisher, Douglas; Frey, Nancy; Lapp, Diane

2012-01-01

Students enter the middle grades with varying amounts of background knowledge. Teachers must assess student background knowledge for gaps or misconceptions and then provide instruction to build on that base. This article discusses effective strategies for assessing and developing students' background knowledge so they can become independent…

Designing Capacity-Building in E-Learning Expertise: Challenges and Strategies

ERIC Educational Resources Information Center

Aczel, J. C.; Peake, S. R.; Hardy, P.

2008-01-01

This research study looks at how organizations in developing countries perceive the challenge of building capacity in e-learning expertise. Data was collected on six such organizations, and a range of perceived rationales and constraints were identified. The paper hypothesizes a four-part framework to define the e-learning capacity gaps that these…

Gap Junctional Coupling in Lenses from α8 Connexin Knockout Mice

PubMed Central

Baldo, George J.; Gong, Xiaohua; Martinez-Wittinghan, Francisco J.; Kumar, Nalin M.; Gilula, Norton B.; Mathias, Richard T.

2001-01-01

Lens fiber cell gap junctions contain α3 (Cx46) and α8 (Cx50) connexins. To examine the roles of the two different connexins in lens physiology, we have genetically engineered mice lacking either α3 or α8 connexin. Intracellular impedance studies of these lenses were used to measure junctional conductance and its sensitivity to intracellular pH. In Gong et al. 1998, we described results from α3 connexin knockout lenses. Here, we present original data from α8 connexin knockout lenses and a comparison with the previous results. The lens has two functionally distinct domains of fiber cell coupling. In wild-type mouse lenses, the outer shell of differentiating fibers (see 1, DF) has an average coupling conductance per area of cell–cell contact of ∼1 S/cm2, which falls to near zero when the cytoplasm is acidified. In the inner core of mature fibers (see 1, MF), the average coupling conductance is ∼0.4 S/cm2, and is insensitive to acidification of the cytoplasm. Both connexin isoforms appear to contribute about equally in the DF since the coupling conductance for either heterozygous knockout (+/−) was ∼70% of normal and 30–40% of the normal for both −/− lenses. However, their contribution to the MF was different. About 50% of the normal coupling conductance was found in the MF of α3 +/− lenses. In contrast, the coupling of MF in the α8 +/− lenses was the same as normal. Moreover, no coupling was detected in the MF of α3 −/− lenses. Together, these results suggest that α3 connexin alone is responsible for coupling MF. The pH- sensitive gating of DF junctions was about the same in wild-type and α3 connexin −/− lenses. However, in α8 −/− lenses, the pure α3 connexin junctions did not gate closed in the response to acidification. Since α3 connexin contributes about half the coupling conductance in DF of wild-type lenses, and that conductance goes to zero when the cytoplasmic pH drops, it appears α8 connexin regulates the gating of α3 connexin. Both connexins are clearly important to lens physiology as lenses null for either connexin lose transparency. Gap junctions in the MF survive for the lifetime of the organism without protein turnover. It appears that α3 connexin provides the long-term communication in MF. Gap junctions in DF may be physiologically regulated since they are capable of gating when the cytoplasm is acidified. It appears α8 connexin is required for gating in DF. PMID:11696604

Tensile strength of ramie yarn (spinning by machine)/HDPE thermoplastic matrix composites

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

Banowati, Lies, E-mail: liesbano@gmail.com; Hadi, Bambang K., E-mail: bkhadi@ae.itb.ac.id; Suratman, Rochim, E-mail: rochim@material.itb.ac.id

2016-03-29

Technological developments should be trooped to prevent a gap between technology and environmental sustainability, then it needs to be developed “Green technology”. In this research is making of green composites which use natural fiber ramie as reinforcement. Whereas the matrix used was HDPE (High Density Polyethylene) thermoplastic polymer which could be recycled and had a good formability and flexibility. The ramie yarns and fibers for unidirectional (0°) direction respectively were mixed with HDPE powder and processed using hot compression molding. The surface morphology was observed by SEM (Scanning Electrone Microscopy). Results showed that both tensile strength of the ramie fiber/HDPEmore » composites increased in comparison with the ramie yarn (spinning by machine)/HDPE composites. However, the ramie yarn (spinning by machine)/HDPE composites have a good producibility for wider application. Analysis of the test results using the Weibull distribution as approaches to modeling the reliability of the specimens.« less

Black phosphorus: a two-dimension saturable absorption material for mid-infrared Q-switched and mode-locked fiber lasers

PubMed Central

Li, Jianfeng; Luo, Hongyu; Zhai, Bo; Lu, Rongguo; Guo, Zhinan; Zhang, Han; Liu, Yong

2016-01-01

Black phosphorus (BP) as a novel class of two-dimension (2D) materials has recently attracted enormous attention as a result of its unique physical and chemical features. The remarkably strong light-matter interaction and tunable direct band-gap at a wide range make it an ideal candidate especially in the mid-infrared wavelength region as the saturable absorber (SA). In this paper, the simple and effective liquid phase exfoliation (LPE) method was used to fabricate BP. By introducing the same BP SA into two specifically designed rare earth ions doped fluoride fiber lasers at mid-infrared wavebands, Q-switching with the pulse energy of 4.93 μJ and mode-locking with the pulse duration of 8.6 ps were obtained, respectively. The operation wavelength of ~2970 nm for generated pulse is the reported longest wavelength for BP SA based fiber lasers. PMID:27457338

The long-term performance of electrically charged filters in a ventilation system.

PubMed

Raynor, Peter C; Chae, Soo Jae

2004-07-01

The efficiency and pressure drop of filters made from polyolefin fibers carrying electrical charges were compared with efficiency and pressure drop for filters made from uncharged glass fibers to determine if the efficiency of the charged filters changed with use. Thirty glass fiber filters and 30 polyolefin fiber filters were placed in different, but nearly identical, air-handling units that supplied outside air to a large building. Using two kinds of real-time aerosol counting and sizing instruments, the efficiency of both sets of filters was measured repeatedly for more than 19 weeks while the air-handling units operated almost continuously. Pressure drop was recorded by the ventilation system's computer control. Measurements showed that the efficiency of the glass fiber filters remained almost constant with time. However, the charged polyolefin fiber filters exhibited large efficiency reductions with time before the efficiency began to increase again toward the end of the test. For particles 0.6 microm in diameter, the efficiency of the polyolefin fiber filters declined from 85% to 45% after 11 weeks before recovering to 65% at the end of the test. The pressure drops of the glass fiber filters increased by about 0.40 in. H2O, whereas the pressure drop of the polyolefin fiber filters increased by only 0.28 in. H2O. The results indicate that dust loading reduces the effectiveness of electrical charges on filter fibers. Copyright 2004 JOEH, LLC

The Dual Functions of WLIM1a in Cell Elongation and Secondary Wall Formation in Developing Cotton Fibers[C][W

PubMed Central

Han, Li-Bo; Li, Yuan-Bao; Wang, Hai-Yun; Wu, Xiao-Min; Li, Chun-Li; Luo, Ming; Wu, Shen-Jie; Kong, Zhao-Sheng; Pei, Yan; Jiao, Gai-Li; Xia, Gui-Xian

2013-01-01

LIN-11, Isl1 and MEC-3 (LIM)-domain proteins play pivotal roles in a variety of cellular processes in animals, but plant LIM functions remain largely unexplored. Here, we demonstrate dual roles of the WLIM1a gene in fiber development in upland cotton (Gossypium hirsutum). WLIM1a is preferentially expressed during the elongation and secondary wall synthesis stages in developing fibers. Overexpression of WLIM1a in cotton led to significant changes in fiber length and secondary wall structure. Compared with the wild type, fibers of WLIM1a-overexpressing plants grew longer and formed a thinner and more compact secondary cell wall, which contributed to improved fiber strength and fineness. Functional studies demonstrated that (1) WLIM1a acts as an actin bundler to facilitate elongation of fiber cells and (2) WLIM1a also functions as a transcription factor to activate expression of Phe ammonia lyase–box genes involved in phenylpropanoid biosynthesis to build up the secondary cell wall. WLIM1a localizes in the cytosol and nucleus and moves into the nucleus in response to hydrogen peroxide. Taken together, these results demonstrate that WLIM1a has dual roles in cotton fiber development, elongation, and secondary wall formation. Moreover, our study shows that lignin/lignin-like phenolics may substantially affect cotton fiber quality; this finding may guide cotton breeding for improved fiber traits. PMID:24220634

The Audacity of Fiber-Wireless (FiWi) Networks

NASA Astrophysics Data System (ADS)

Maier, Martin; Ghazisaidi, Navid; Reisslein, Martin

A plethora of enabling optical and wireless technologies have been emerging that can be used to build future-proof bimodal fiber-wireless (FiWi) broadband access networks. After overviewing key enabling radio-over-fiber (RoF) and radio-and-fiber (R&F) technologies and briefly surveying the state of the art of FiWi networks, we introduce an Ethernet-based access-metro FiWi network, called SuperMAN, that integrates next-generation WiFi and WiMAX networks with WDM-enhanced EPON and RPR networks. Throughout the paper we pay close attention to the technical challenges and opportunities of FiWi networks, but also elaborate on their societal benefits and potential to shift the current research focus from optical-wireless networking to the exploitation of personal and in-home computing facilities to create new unforeseen services and applications as we are about to enter the Petabyte age.

Fiber optic sensor system for entrance areas monitoring

NASA Astrophysics Data System (ADS)

Fajkus, Marcel; Nedoma, Jan; Kepak, Stanislav; Cubik, Jakub; Jargus, Jan; Zboril, Ondřej; Martinek, Radek; Vasinek, Vladimir

2017-10-01

Authors of this article present the fiber-optic system based on fiber Bragg gratings (FBGs) which are used to secure the entrance areas such as buildings, halls, warehouses, etc. The system uses the specially encapsulated sensory array of fiber Bragg gratings which are implemented into the floor or on the floor and allows for monitoring the area of 1 m2 up to 100 m2 depending on the number of FBG sensors. The sensory array is characterized by immunity to electromagnetic interference (EMI), passivity regarding electrical power supply, the possibility of remote evaluation (up to units of km) and high sensitivity. Proposed sensor system has detection capability greater than 99 % and furthermore, provides information about the weight load to an accuracy of +/- 5 kg. The concept has been tested in a real environment within the test polygon for several weeks. As the reference devices, we used the CCTV (Closed Circuit Television).

Building Nanoporous Metal-Organic Frameworks "Armor" on Fibers for High-Performance Composite Materials.

PubMed

Yang, Xiaobin; Jiang, Xu; Huang, Yudong; Guo, Zhanhu; Shao, Lu

2017-02-15

The nanoporous metal-organic frameworks (MOFs) "armor" is in situ intergrown onto the surfaces of carbon fibers (CFs) by nitric acid oxidization to supply nucleation sites and serves as a novel interfacial linker between the fiber and polymer matrix and a smart cushion to release interior and exterior applied forces. Simultaneous enhancements of the interfacial and interlaminar shear strength as well as the tensile strength of CFs were achieved. With the aid of an ultrasonic "cleaning" process, the optimized surface energy and tensile strength of CFs with a MOF "armor" are 83.79 mN m -1 and 5.09 GPa, for an increase of 102% and 11.6%, respectively. Our work finds that the template-induced nucleation of 3D MOF onto 1D fibers is a general and promising approach toward advanced composite materials for diverse applications to meet scientific and technical demands.

Transmission of 2.5 Gbit/s Spectrum-sliced WDM System for 50 km Single-mode Fiber

NASA Astrophysics Data System (ADS)

Ahmed, Nasim; Aljunid, Sayed Alwee; Ahmad, R. Badlisha; Fadil, Hilal Adnan; Rashid, Mohd Abdur

2011-06-01

The transmission of a spectrum-sliced WDM channel at 2.5 Gbit/s for 50 km of single mode fiber using an system channel spacing only 0.4 nm is reported. We have investigated the system performance using NRZ modulation format. The proposed system is compared with conventional system. The system performance is characterized as the bit-error-rate (BER) received against the system bit rates. Simulation results show that the NRZ modulation format performs well for 2.5 Gbit/s system bit rates. Using this narrow channel spectrum-sliced technique, the total number of multiplexed channels can be increased greatly in WDM system. Therefore, 0.4 nm channel spacing spectrum-sliced WDM system is highly recommended for the long distance optical access networks, like the Metro Area Network (MAN), Fiber-to-the-Building (FTTB) and Fiber-to-the-Home (FTTH).

Polyimides formulated from a partially fluorinated diamine for aerospace tribological applications

NASA Technical Reports Server (NTRS)

Fusaro, R. L.

1983-01-01

Preliminary tribological studies on polyimides formulated from the diamine 2,2-bis 4-(4-aminophenoxy)phenyl hexafluorapane (4-BDAF) indicate that polyimides formulated from this diamine have excellent potential for high temperature tribological applications. The dianhydrides used to make the polyimides were pyromellitic (PMDA) and benzophenonetetracarboxylic acid (BTDA). Friction and wear studies at 25 and 200 C indicate that polyimides formulated using 50 mole percent of the PMDA dianhydride and 50 mole percent of the BTDA dianhydride perform better than polyimides formulated solely with the BTDA dianhydride. Graphite fiber reinforced polyimide composites were formulated with the polyimide made from the BTDA dianhydride, both graphitic and non-graphitic fibers were evaluated. Graphitic fibers produced better tribological results, since thin, flowing, "layer-like' transfer films were produced which did not build-up with long sliding durations. Non-graphitic fibers did not produce this type of transfer.

Deep learning and model predictive control for self-tuning mode-locked lasers

NASA Astrophysics Data System (ADS)

Baumeister, Thomas; Brunton, Steven L.; Nathan Kutz, J.

2018-03-01

Self-tuning optical systems are of growing importance in technological applications such as mode-locked fiber lasers. Such self-tuning paradigms require {\\em intelligent} algorithms capable of inferring approximate models of the underlying physics and discovering appropriate control laws in order to maintain robust performance for a given objective. In this work, we demonstrate the first integration of a {\\em deep learning} (DL) architecture with {\\em model predictive control} (MPC) in order to self-tune a mode-locked fiber laser. Not only can our DL-MPC algorithmic architecture approximate the unknown fiber birefringence, it also builds a dynamical model of the laser and appropriate control law for maintaining robust, high-energy pulses despite a stochastically drifting birefringence. We demonstrate the effectiveness of this method on a fiber laser which is mode-locked by nonlinear polarization rotation. The method advocated can be broadly applied to a variety of optical systems that require robust controllers.

A hybrid lightwave transmission system based on light injection/optoelectronic feedback techniques and fiber-VLLC integration

NASA Astrophysics Data System (ADS)

Tsai, Wen-Shing; Lu, Hai-Han; Li, Chung-Yi; Chen, Bo-Rui; Lin, Hung-Hsien; Lin, Dai-Hua

2016-04-01

A hybrid lightwave transmission system based on light injection/optoelectronic feedback techniques and fiber-visible laser light communication (VLLC) integration is proposed and experimentally demonstrated. To be the first one of its kind in employing light injection and optoelectronic feedback techniques in a fiber-VLLC integration lightwave transmission system, the light is successfully directly modulated with Community Access Television (CATV), 16-QAM, and 16-QAM-OFDM signals. Over a 40 km SMF and a 10 m free-space VLLC transport, good performances of carrier-to-noise ratio (CNR)/composite second-order (CSO)/composite triple-beat (CTB)/bit error rate (BER) are achieved for CATV/16-QAM/16-QAM-OFDM signals transmission. Such a hybrid lightwave transmission system would be very useful since it can provide broadband integrated services including CATV, Internet, and telecommunication services over both distribute fiber and in-building networks.

Smooth muscle-like tissue constructs with circumferentially oriented cells formed by the cell fiber technology.

PubMed

Hsiao, Amy Y; Okitsu, Teru; Onoe, Hiroaki; Kiyosawa, Mahiro; Teramae, Hiroki; Iwanaga, Shintaroh; Kazama, Tomohiko; Matsumoto, Taro; Takeuchi, Shoji

2015-01-01

The proper functioning of many organs and tissues containing smooth muscles greatly depends on the intricate organization of the smooth muscle cells oriented in appropriate directions. Consequently controlling the cellular orientation in three-dimensional (3D) cellular constructs is an important issue in engineering tissues of smooth muscles. However, the ability to precisely control the cellular orientation at the microscale cannot be achieved by various commonly used 3D tissue engineering building blocks such as spheroids. This paper presents the formation of coiled spring-shaped 3D cellular constructs containing circumferentially oriented smooth muscle-like cells differentiated from dedifferentiated fat (DFAT) cells. By using the cell fiber technology, DFAT cells suspended in a mixture of extracellular proteins possessing an optimized stiffness were encapsulated in the core region of alginate shell microfibers and uniformly aligned to the longitudinal direction. Upon differentiation induction to the smooth muscle lineage, DFAT cell fibers self-assembled to coiled spring structures where the cells became circumferentially oriented. By changing the initial core-shell microfiber diameter, we demonstrated that the spring pitch and diameter could be controlled. 21 days after differentiation induction, the cell fibers contained high percentages of ASMA-positive and calponin-positive cells. Our technology to create these smooth muscle-like spring constructs enabled precise control of cellular alignment and orientation in 3D. These constructs can further serve as tissue engineering building blocks for larger organs and cellular implants used in clinical treatments.

Smooth Muscle-Like Tissue Constructs with Circumferentially Oriented Cells Formed by the Cell Fiber Technology

PubMed Central

Hsiao, Amy Y.; Okitsu, Teru; Onoe, Hiroaki; Kiyosawa, Mahiro; Teramae, Hiroki; Iwanaga, Shintaroh; Kazama, Tomohiko; Matsumoto, Taro; Takeuchi, Shoji

2015-01-01

The proper functioning of many organs and tissues containing smooth muscles greatly depends on the intricate organization of the smooth muscle cells oriented in appropriate directions. Consequently controlling the cellular orientation in three-dimensional (3D) cellular constructs is an important issue in engineering tissues of smooth muscles. However, the ability to precisely control the cellular orientation at the microscale cannot be achieved by various commonly used 3D tissue engineering building blocks such as spheroids. This paper presents the formation of coiled spring-shaped 3D cellular constructs containing circumferentially oriented smooth muscle-like cells differentiated from dedifferentiated fat (DFAT) cells. By using the cell fiber technology, DFAT cells suspended in a mixture of extracellular proteins possessing an optimized stiffness were encapsulated in the core region of alginate shell microfibers and uniformly aligned to the longitudinal direction. Upon differentiation induction to the smooth muscle lineage, DFAT cell fibers self-assembled to coiled spring structures where the cells became circumferentially oriented. By changing the initial core-shell microfiber diameter, we demonstrated that the spring pitch and diameter could be controlled. 21 days after differentiation induction, the cell fibers contained high percentages of ASMA-positive and calponin-positive cells. Our technology to create these smooth muscle-like spring constructs enabled precise control of cellular alignment and orientation in 3D. These constructs can further serve as tissue engineering building blocks for larger organs and cellular implants used in clinical treatments. PMID:25734774

Production of fiberglass/metal composite material suitable for building habitat and manufacturing facilities

NASA Technical Reports Server (NTRS)

1987-01-01

The production of a fiberglass/metal composite material suitable for building habitats and manufacturing facilities was the project for Clemson. The concept and development of the knowledge necessary to produce glass fibers originated in the spring semester. During the summer, while at Johnson Space Center, fiberglass from a rock composition similar to ones found at the Apollo 16 site on the moon was successfully produced. The project this year was a continuation of last year's studies. We addressed the following problems which emerged as the work progressed: (1) Methods for coating the fibers with a metal were explored. We manufactured composites in two stages: Glass fibers without any coating on them; and fibers coated with metals as they were made. This proved to be a difficult process. Future activities include using a chemical vapor deposition process on fibers which have been made. (2) A glass furnace was developed which relies primarily on solar energy for melting the glass. The temperature of the melted glass is maintained by electrical means. The design is for 250 kg of glass per day. An electrical engineering student developed a scheme for controlling the melting and manufacturing process from the earth. This was done to minimize the human risk. Graphite refractories are relied on to contain the melt. (3) The glass composition chosen for the project is a relatively pure anorthite which is available in the highland regions of the lunar surface. A major problems with this material is that it melts at a comparatively high temperature. This problem will be solved by using graphite refractory materials for the furnace. The advantage of this glass composition is that it is very stable and does not tend to crystallize. (4) We have also refined the experimental furnace and fiber making machinery which we will be using at Johnson Space Center this summer. We believe that we will be able to draw and coat glass fibers in a vacuum for use in composites. We intend to make and test the mechanical properties of these composites.

Embedded Active Fiber Optic Sensing Network for Structural Health Monitoring in Harsh Environments

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

Wang, Anbo

This report summarizes technical progress on the program “Embedded Active Fiber Optic Sensing Network for Structural Health Monitoring in Harsh Environments” funded by the National Energy Technology Laboratory of the U.S. Department of Energy, and performed by the Center for Photonics Technology at Virginia Tech. The objective of this project is to develop a first-of-a-kind technology for remote fiber optic generation and detection of acoustic waves for structural health monitoring in harsh environments. During the project period, which is from April 1, 2013 to Septemeber 30, 2016, three different acoustic generation mechanisms were studied in detail for their applications inmore » building a fiber optic acoustic generation unit (AGU), including laser induced plasma breakdown (LIP), Erbium-doped fiber laser absorption, and metal laser absorption. By comparing the performance of the AGUs designed based on these three mechanisms and analyzing the experimental results with simulations, the metal laser absorption method was selected to build a complete fiber optic structure health monitoring (FO-SHM) system for the proposed high temperature multi-parameter structure health monitoring application. Based on the simulation of elastic wave propagation and fiber Bragg grating acoustic pulse detection, an FO-SHM element together with a completed interrogation system were designed and built. This system was first tested on an aluminum piece in the low-temperature range and successfully demonstrated its capability of multi-parameter monitoring and multi-point sensing. In the later stages of the project, the research was focused on improving the surface attachment design and preparing the FO-SHM element for high temperature environment tests. After several upgrades to the surface attachment methods, the FO-SHM element was able to work reliably up to 600oC when attached to P91 pipes, which are the target material of this project. In the final stage of this project, this FO-SHM sensing system was tested in the simulated harsh environment for its multi-parameter monitoring performance and high-temperature survivability.« less

MNASA as a Test for Carbon Fiber Thermal Barrier Development

NASA Technical Reports Server (NTRS)

Bauer, Paul; McCool, Alex (Technical Monitor)

2001-01-01

A carbon fiber rope thermal barrier is being evaluated as a replacement for the conventional room temperature vulcanizing (RTV) thermal barrier that is currently used to protect o-rings in Reusable Solid Rocket Motor (RSRM) nozzle joints. Performance requirements include its ability to cool any incoming, hot propellant gases that fill and pressurize the nozzle joints, filter slag and particulates, and to perform adequately in various joint assembly conditions as well as dynamic flight motion. Modified National Aeronautics and Space Administration (MNASA) motors, with their inherent and unique ability to replicate select RSRM internal environment features, were an integral step in the development path leading to full scale RSRM static test demonstration of the carbon fiber rope (CFR) joint concept. These 1/4 scale RSRM motors serve to bridge the gap between the other classes of subscale test motors (extremely small and moderate duration, or small scale and short duration) and the critical asset RSRM static test motors. A series of MNASA tests have been used to demonstrate carbon fiber rope performance and have provided rationale for implementation into a full-scale static motor and flight qualification.

A state of the art review on reinforced concrete beams with openings retrofitted with FRP

NASA Astrophysics Data System (ADS)

Osman, Bashir H.; Wu, Erjun; Ji, Bohai; S Abdelgader, Abdeldime M.

2016-09-01

The use of externally bonded fiber reinforced polymer (FRP) sheets, strips or steel plates is a modern and convenient way for strengthening of reinforced concrete (RC) beams. Several researches have been carried out on reinforced concrete beams with web openings that strengthened using fiber reinforced polymer composite. Majority of researches focused on shear strengthening compared with flexural strengthening, while others studied the effect of openings on shear and flexural separately with various loading. This paper investigates the impact of more than sixty articles on opening reinforced concrete beams with and without strengthening by fiber reinforcement polymers FRP. Moreover, important practical issues, which are contributed in shear strengthening of beams with different strengthening techniques, such as steel plate and FRP laminate, and detailed with various design approaches are discussed. Furthermore, a simple technique of applying fiber reinforced polymer contributed with steel plate for strengthening the RC beams with openings under different load application is concluded. Directions for future research based on the existing gaps of the present works are presented.

A novel hypothesis about mechanisms affecting conduction velocity of central myelinated fibers.

PubMed

Adriano, Enrico; Perasso, Luisa; Panfoli, Isabella; Ravera, Silvia; Gandolfo, Carlo; Mancardi, Gianluigi; Morelli, Alessandro; Balestrino, Maurizio

2011-10-01

The hypothesis that gap junctions are implicated in facilitating axonal conduction has not yet been experimentally demonstrated at the electrophysiological level. We found that block of gap junctions with oleammide slows down axonal conduction velocity in the hippocampal Schaffer collaterals, a central myelinated pathway. Moreover, we explored the possibility that support by the oligodendrocyte to the axon involves energy metabolism, a hypothesis that has been recently proposed by some of us. In agreement with this hypothesis, we found that the effect of oleammide was reversed by pretreatment with creatine, a compound that is known to increase the energy charge of the tissue. Moreover, conduction velocity was also slowed down by anoxia, a treatment that obviously decreases the energy charge of the tissue, and by ouabain, a compound that blocks plasma membrane Na/K-ATPase, the main user of ATP in the brain. We hypothesize that block of gap junctions slows down conduction velocity in central myelinated pathways because oligodendrocytes synthesize ATP and transfer it to the axon through gap junctions.

Filler bar heating due to stepped tiles in the shuttle orbiter thermal protection system

NASA Technical Reports Server (NTRS)

Petley, D. H.; Smith, D. M.; Edwards, C. L. W.; Patten, A. B.; Hamilton, H. H., II

1983-01-01

An analytical study was performed to investigate the excessive heating in the tile to tile gaps of the Shuttle Orbiter Thermal Protection System due to stepped tiles. The excessive heating was evidence by visible discoloration and charring of the filler bar and strain isolation pad that is used in the attachment of tiles to the aluminum substrate. Two tile locations on the Shuttle orbiter were considered, one on the lower surface of the fuselage and one on the lower surface of the wing. The gap heating analysis involved the calculation of external and internal gas pressures and temperatures, internal mass flow rates, and the transient thermal response of the thermal protection system. The results of the analysis are presented for the fuselage and wing location for several step heights. The results of a study to determine the effectiveness of a half height ceramic fiber gap filler in preventing hot gas flow in the tile gaps are also presented.

Quantification of short and long asbestos fibers to assess asbestos exposure: a review of fiber size toxicity

PubMed Central

2014-01-01

The fibrogenicity and carcinogenicity of asbestos fibers are dependent on several fiber parameters including fiber dimensions. Based on the WHO (World Health Organization) definition, the current regulations focalise on long asbestos fibers (LAF) (Length: L ≥ 5 μm, Diameter: D < 3 μm and L/D ratio > 3). However air samples contain short asbestos fibers (SAF) (L < 5 μm). In a recent study we found that several air samples collected in buildings with asbestos containing materials (ACM) were composed only of SAF, sometimes in a concentration of ≥10 fibers.L−1. This exhaustive review focuses on available information from peer-review publications on the size-dependent pathogenetic effects of asbestos fibers reported in experimental in vivo and in vitro studies. In the literature, the findings that SAF are less pathogenic than LAF are based on experiments where a cut-off of 5 μm was generally made to differentiate short from long asbestos fibers. Nevertheless, the value of 5 μm as the limit for length is not based on scientific evidence, but is a limit for comparative analyses. From this review, it is clear that the pathogenicity of SAF cannot be completely ruled out, especially in high exposure situations. Therefore, the presence of SAF in air samples appears as an indicator of the degradation of ACM and inclusion of their systematic search should be considered in the regulation. Measurement of these fibers in air samples will then make it possible to identify pollution and anticipate health risk. PMID:25043725

FIBER AND INTEGRATED OPTICS: Problems involved in the profiling of quantum wells and barriers for optoelectronic applications

NASA Astrophysics Data System (ADS)

Eliseev, P. G.; Zakhar'ev, B. N.

1992-10-01

Some important problems concerning the profiling of the potential energy in quantum-well lasers are discussed. The goals being sought are to introduce a relative shift of the levels of localized states, to introduce an energy gap, and to reduce the transmission of barriers without increasing their height.

"This Is How We Roll!": How "Successful" White Social Studies Teachers Build Solidarity with African American Students

ERIC Educational Resources Information Center

Boucher, Michael Lee, Jr.

2013-01-01

Despite a decade of concentration on closing the pervasive achievement gap in America, White students and Black students still attend schools with unequal results. Many strategies aimed at closing the gap exist, including increasing the number of African American teachers, but the majority of urban teachers are White, which will remain the case…

Lessons along the Cultural Spectrum: Educators Can Build on the Variety of Cultures and Daily Experiences to Shape Students' Learning and Development

ERIC Educational Resources Information Center

Williams, Belinda

2006-01-01

Although economically disadvantaged and minority students made some gains in their academic achievement performance, education reforms still fail to close the academic achievement gap between them. A discussion of the factors that influence the achievement gap is presented and provides some professional development implications. According to the…

Glass fiber effect on mechanical properties of Eco-SCC

NASA Astrophysics Data System (ADS)

Prasad M. L., V.; Loksesh, G.; Ramanjaneyulu, B.; Venkatesh, S.; Mousumi, K.

2017-07-01

Sustainable Construction encouraging the use of recycled materials and implies adoption of fewer natural resources in buildings and other infrastructure. In this paper Quarry Dust (QD) is used as partial replacement for River Sand (RS) to make Self Compacting Concrete (SCC) of grade M40. Glass fiber is used as strengthening material to the developed concrete. The present study mainly focused to develop Eco-SCC using QD. In this study it was found that, for developing Eco-SCC, what is the optimum dosage of replacement of QD in RS. Fresh properties of SCC are satisfying the EFNARC specifications and also target strength is achieved. Further it is concluded that, with the glass fiber addition there is an improvement in the split and flexural strength values.

Implementation and characterization of a stable optical frequency distribution system.

PubMed

Bernhardt, Birgitta; Hänsch, Theodor W; Holzwarth, Ronald

2009-09-14

An optical frequency distribution system has been developed that continuously delivers a stable optical frequency of 268 THz (corresponding to a wavelength of 1118 nm) to different experiments in our institute. For that purpose, a continuous wave (cw) fiber laser has been stabilized onto a frequency comb and distributed across the building by the use of a fiber network. While the light propagates through the fiber, acoustic and thermal effects counteract against the stability and accuracy of the system. However, by employing proper stabilization methods a stability of 2 x 10(-13) tau(-1/2) is achieved, limited by the available radio frequency (RF) reference. Furthermore, the issue of counter-dependant results of the Allan deviation was examined during the data evaluation.

Statistical analysis of interfacial gap in a cementless stem FE model.

PubMed

Park, Youngbae; Choi, Donok; Hwang, Deuk Soo; Yoon, Yong-San

2009-02-01

In cementless total hip arthroplasty, a fair amount of interfacial gap exists between the femoral stem and the bone. However, the effect of these gaps on the mechanical stability of the stem is poorly understood. In this paper, a finite element model with various interfacial gap definitions is used to quantify the effect of interfacial gaps on the primary stability of a Versys Fiber Metal Taper stem under stair climbing loads. In the first part, 500 random interfacial gap definitions were simulated. The resulting micromotion was approximately inversely proportional to the contact ratio, and the variance of the micromotion was greater with a lower contact ratio. Moreover, when the magnitude of the micromotion was compared between the gap definitions that had contact at a specific site and those that had no contact at that site, it was found that gaps located in the proximal-medial region of the stem surface had the most important effect on the micromotion. In a second trial, 17 gap definitions mimicking a gap pattern that has been observed experimentally were simulated. For a given contact ratio, the micromotion observed in the second trial was lower than the average result of those in the first, where the gaps were placed randomly. In either trial, when the contact ratio was higher than 40%, the micromotion showed no significant difference (first trial) or a gentle slope (-0.24 mum% in the second trial) in relation to the contact ratio. Considering the reported contact ratios for properly implanted stems, variations in the amount of interfacial gap would not likely cause a drastic difference in micromotion, and this effect could be easily overshadowed by other clinical factors. In conclusion, differences in interfacial gaps are not expected to have a noticeable effect on the clinical micromotion of this cementless stem.

Monolithic multi-color light emission/detection device

DOEpatents

Wanlass, Mark W.

1995-01-01

A single-crystal, monolithic, tandem, multi-color optical transceiver device is described, including (a) an InP substrate having upper and lower surfaces, (b) a first junction on the upper surface of the InP substrate, (c) a second junction on the first junction. The first junction is preferably GaInAsP of defined composition, and the second junction is preferably InP. The two junctions are lattice matched. The second junction has a larger energy band gap than the first junction. Additional junctions having successively larger energy band gaps may be included. The device is capable of simultaneous and distinct multi-color emission and detection over a single optical fiber.

Hygroscopic expansion of self-adhesive resin cements and the integrity of all-ceramic crowns.

PubMed

Kirsten, Magdalena; Matta, Ragai Edward; Belli, Renan; Lohbauer, Ulrich; Wichmann, Manfred; Petschelt, Anselm; Zorzin, José

2018-04-27

Low pH neutralization and subsequent remnant hydrophilicity can lead to hygroscopic expansion of self-adhesive resin cements (SARCs) after water storage. The aim of this in vitro study was to investigate the effects of hygroscopic expansion of SARCs, used as luting and partial core build-up material, on integrity and cement gap thickness increase of all-ceramic CAD/CAM crowns. Human third molars (n=48) were prepared and anatomical all-ceramic CAD/CAM crowns were manufactured (VITABLOCS Mark II, VITA Zahnfabrik). Crowns internal surfaces were HF etched and silanized. The prepared teeth with their respective crowns were divided into 6 groups (n=8). In groups 1, 3 and 5 the coronal dentin was removed to simulate a partial core build-up. Groups 1 and 2 were luted with iCEM (Heraeus Kulzer), 3 and 4 with RelyX Unicem 2 Automix (3M), 5 and 6 with Variolink Esthetic DC (Ivoclar Vivadent). All specimens were dual cured and stored in distilled water at 37°C. Crown integrity was controlled at baseline and in regular intervals until 180 days. Cement gap thickness was measured using an optical 3D scanner (ATOS Triple scan, GOM) at baseline and after 180 days. Crown integrity was statistically analysed using Kaplan-Meier survival analysis and cement gap thickness increase using two-way ANOVA (α=0.05). After 180 days storage, crack formation was observed in all specimens of group 1 (mean survival time of 85.5 days), in one specimen of group 2 and in two specimens of group 4. Two-way ANOVA analysis revealed a statistically significant interaction between material type and build-up on cement gap size increase for iCEM. Within the limits of this study, the application of SARCs with low pH neutralization as partial build-up material under CAD/CAM crowns is not recommended for clinical use. Copyright © 2018 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.

Asbestos' Impact on Indoor Air Quality

EPA Pesticide Factsheets

Asbestos is a mineral fiber that has been used commonly in a variety of building construction materials for insulation and as a fire-retardant. EPA and CPSC have banned several asbestos products. Manufacturers have also voluntarily limited uses of asbesto

Superior Sensor Making Sense in Military, Medicine

NASA Technical Reports Server (NTRS)

2004-01-01

A fiber-optic voltage sensor developed a decade ago for NASA's aircraft and space power systems has been the building block for a string of new sensor products offering safe, accurate detection and measurement for electrically noisy and hazardous environments.

24 CFR 200.942 - Supplementary specific procedural requirements under HUD building product standards and...

Code of Federal Regulations, 2010 CFR

2010-04-01

... the following standards: (i) AATCC 20A-81—Fiber Analysis: Quantitative; (ii) AATCC 16E-82... 12215, Research Triangle Park, NC 27709; (ii) American Society for Testing and Materials (ASTM), 1916...

24 CFR 200.942 - Supplementary specific procedural requirements under HUD building product standards and...

Code of Federal Regulations, 2014 CFR

2014-04-01

... the following standards: (i) AATCC 20A-81—Fiber Analysis: Quantitative; (ii) AATCC 16E-82... 12215, Research Triangle Park, NC 27709; (ii) American Society for Testing and Materials (ASTM), 1916...

24 CFR 200.942 - Supplementary specific procedural requirements under HUD building product standards and...

Code of Federal Regulations, 2011 CFR

2011-04-01

... the following standards: (i) AATCC 20A-81—Fiber Analysis: Quantitative; (ii) AATCC 16E-82... 12215, Research Triangle Park, NC 27709; (ii) American Society for Testing and Materials (ASTM), 1916...

24 CFR 200.942 - Supplementary specific procedural requirements under HUD building product standards and...

Code of Federal Regulations, 2013 CFR

2013-04-01

... the following standards: (i) AATCC 20A-81—Fiber Analysis: Quantitative; (ii) AATCC 16E-82... 12215, Research Triangle Park, NC 27709; (ii) American Society for Testing and Materials (ASTM), 1916...

24 CFR 200.942 - Supplementary specific procedural requirements under HUD building product standards and...

Code of Federal Regulations, 2012 CFR

2012-04-01

... the following standards: (i) AATCC 20A-81—Fiber Analysis: Quantitative; (ii) AATCC 16E-82... 12215, Research Triangle Park, NC 27709; (ii) American Society for Testing and Materials (ASTM), 1916...

Super-Strong, Super-Stiff Macrofibers with Aligned, Long Bacterial Cellulose Nanofibers.

PubMed

Wang, Sha; Jiang, Feng; Xu, Xu; Kuang, Yudi; Fu, Kun; Hitz, Emily; Hu, Liangbing

2017-09-01

With their impressive properties such as remarkable unit tensile strength, modulus, and resistance to heat, flame, and chemical agents that normally degrade conventional macrofibers, high-performance macrofibers are now widely used in various fields including aerospace, biomedical, civil engineering, construction, protective apparel, geotextile, and electronic areas. Those macrofibers with a diameter of tens to hundreds of micrometers are typically derived from polymers, gel spun fibers, modified carbon fibers, carbon-nanotube fibers, ceramic fibers, and synthetic vitreous fibers. Cellulose nanofibers are promising building blocks for future high-performance biomaterials and textiles due to their high ultimate strength and stiffness resulting from a highly ordered orientation along the fiber axis. For the first time, an effective fabrication method is successfully applied for high-performance macrofibers involving a wet-drawing and wet-twisting process of ultralong bacterial cellulose nanofibers. The resulting bacterial cellulose macrofibers yield record high tensile strength (826 MPa) and Young's modulus (65.7 GPa) owing to the large length and the alignment of nanofibers along fiber axis. When normalized by weight, the specific tensile strength of the macrofiber is as high as 598 MPa g -1 cm 3 , which is even substantially stronger than the novel lightweight steel (227 MPa g -1 cm 3 ). © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Automated fiber placement composite manufacturing: The mission at MSFC's Productivity Enhancement Complex

NASA Technical Reports Server (NTRS)

Vickers, John H.; Pelham, Larry I.

1993-01-01

Automated fiber placement is a manufacturing process used for producing complex composite structures. It is a notable leap to the state-of-the-art in technology for automated composite manufacturing. The fiber placement capability was established at the Marshall Space Flight Center's (MSFC) Productivity Enhancement Complex in 1992 in collaboration with Thiokol Corporation to provide materials and processes research and development, and to fabricate components for many of the Center's Programs. The Fiber Placement System (FPX) was developed as a distinct solution to problems inherent to other automated composite manufacturing systems. This equipment provides unique capabilities to build composite parts in complex 3-D shapes with concave and other asymmetrical configurations. Components with complex geometries and localized reinforcements usually require labor intensive efforts resulting in expensive, less reproducible components; the fiber placement system has the features necessary to overcome these conditions. The mechanical systems of the equipment have the motion characteristics of a filament winder and the fiber lay-up attributes of a tape laying machine, with the additional capabilities of differential tow payout speeds, compaction and cut-restart to selectively place the correct number of fibers where the design dictates. This capability will produce a repeatable process resulting in lower cost and improved quality and reliability.

Optical system components for navigation grade fiber optic gyroscopes

NASA Astrophysics Data System (ADS)

Heimann, Marcus; Liesegang, Maximilian; Arndt-Staufenbiel, Norbert; Schröder, Henning; Lang, Klaus-Dieter

2013-10-01

Interferometric fiber optic gyroscopes belong to the class of inertial sensors. Due to their high accuracy they are used for absolute position and rotation measurement in manned/unmanned vehicles, e.g. submarines, ground vehicles, aircraft or satellites. The important system components are the light source, the electro optical phase modulator, the optical fiber coil and the photodetector. This paper is focused on approaches to realize a stable light source and fiber coil. Superluminescent diode and erbium doped fiber laser were studied to realize an accurate and stable light source. Therefor the influence of the polarization grade of the source and the effects due to back reflections to the source were studied. During operation thermal working conditions severely affect accuracy and stability of the optical fiber coil, which is the sensor element. Thermal gradients that are applied to the fiber coil have large negative effects on the achievable system accuracy of the optic gyroscope. Therefore a way of calculating and compensating the rotation rate error of a fiber coil due to thermal change is introduced. A simplified 3 dimensional FEM of a quadrupole wound fiber coil is used to determine the build-up of thermal fields in the polarization maintaining fiber due to outside heating sources. The rotation rate error due to these sources is then calculated and compared to measurement data. A simple regression model is used to compensate the rotation rate error with temperature measurement at the outside of the fiber coil. To realize a compact and robust optical package for some of the relevant optical system components an approach based on ion exchanged waveguides in thin glass was developed. This waveguides are used to realize 1x2 and 1x4 splitter with fiber coupling interface or direct photodiode coupling.

Composite ceramic superconducting wires for electric motor applications

NASA Astrophysics Data System (ADS)

Halloran, John W.

1988-12-01

This is the Second Quarterly report on a project to develop HTSC wire for an HTSC motor. The raw material for fiber production is an improved YBa2Cu3O(7-x) powder. Continuous spools of green YBa2Cu3O(7-x) fiber are being produced. The major effort in fiber spinning is aimed at improving fiber quality and reducing fiber. Binder burnout and sintering has been intensively investigated. Fiber sintering fibers is done by the rapid zone sintering method. A continuous furnace received near the end of this Quarter will be used for continuous sintering. Continuous silver coated green fiber are produced. We have made progress toward continuous cladding using the mechanical cladding concept. The melt spinning process was successfully applied to YBa2Cu3O(7-x) powders at 50 vol percent solids loadings. The cladding work centered on mechanical cladding of silver treated filaments by solder bonding to copper strips. Aluminum deposits on YBa2Cu3O(7-x) filament surfaces were produced by MOCVD at ATM, but the superconductivity was degraded. Electrical characterization work focused on methods of making low resistance contacts on YBa2Cu3O(7-x) filaments. Emerson Motor Division has begun work on DC heteropolar and homopolar motor designs. The mechanical stresses on conventional copper wires during winding have been characterized to determine the mechanical parameters of motor building.

Development and application of nonflammable, high-temperature beta fibers

NASA Technical Reports Server (NTRS)

Dawn, Frederic S.

1989-01-01

Recent advances in fiber technology have contributed to the success of the U.S. space program. The inorganic fiber Beta, developed as a result of efforts begun in the early 1960's and heightened following the January 27, 1967 Apollo fire is unique among inorganic and organic fibers. It has been developed into woven, nonwoven, knitted, braided, coated and printed structures. All of these were used extensively for the Apollo, Skylab, Apollo-Soyuz test project, space shuttle, Spacelab, and satellite programs. In addition to being used successfully in the space program, Beta fibers are being used commercially as firesafe fabrics in homes, hospitals, institutions, public buildings, aircraft, and public transportation, wherever total nonflammability is required. One of the most unique applications of the Beta composite structure is the roofing material for the 80,000-seat Detroit Lion's Silverdome and 5 square miles of the Jeddah International Airport in Saudi Arabia. This fiber has been successfully incorporated into 165 major public construction projects around the globe. The United States alone has used more than 12 million square yards of the material. Beta fiber has been used successfully to date and has a promising future with unlimited potential for both space and commercial application. Efforts are currently underway to improve Beta fiber to meet the requirements of extended service life for the Space Station Freedom, lunar outpost, and Mars exploration missions.

The Girl Game Company: Engaging Latina Girls in Information Technology

ERIC Educational Resources Information Center

Denner, Jill; Bean, Steve; Martinez, Jacob

2009-01-01

This article describes the Girl Game Company's involvement in teaching Latina girls to design and program computer games while building a network of support to help them pursue IT courses and careers. Afterschool programs like the Girl Game Company can fill an important gap by providing opportunities for underserved youth to build IT fluency. A…

Building Teachers' Data-Use Capacity: Insights from Strong and Developing Coaches

ERIC Educational Resources Information Center

Huguet, Alice; Marsh, Julie A.; Farrell, Caitlin C.

2014-01-01

Coaching has become a central strategy in district and school efforts to build teacher capacity to interpret and respond to student learning data. Despite their popularity, there is limited research on the implementation of these initiatives. This article begins to addresses this gap by examining the elements of a coach's practice that appear…

Building Capacity for Research and Audit: Outcomes of a Training Workshop for Pacific Physicians and Nurses

ERIC Educational Resources Information Center

Ekeroma, Alec J.; Kenealy, Tim; Shulruf, Boaz; Nosa, Vili; Hill, Andrew

2015-01-01

Building the research capacity of clinicians in the Pacific Island countries is important in addressing evidence gaps relevant to local policy and clinical practice. This paper aimed to assess the effectiveness of a reproductive health research workshop in increasing research knowledge and intention to perform research amongst a diverse group of…

Statistics of acoustic emissions and stress drops during granular shearing using a stick-slip fiber bundle mode

NASA Astrophysics Data System (ADS)

Cohen, D.; Michlmayr, G.; Or, D.

2012-04-01

Shearing of dense granular materials appears in many engineering and Earth sciences applications. Under a constant strain rate, the shearing stress at steady state oscillates with slow rises followed by rapid drops that are linked to the build up and failure of force chains. Experiments indicate that these drops display exponential statistics. Measurements of acoustic emissions during shearing indicates that the energy liberated by failure of these force chains has power-law statistics. Representing force chains as fibers, we use a stick-slip fiber bundle model to obtain analytical solutions of the statistical distribution of stress drops and failure energy. In the model, fibers stretch, fail, and regain strength during deformation. Fibers have Weibull-distributed threshold strengths with either quenched and annealed disorder. The shape of the distribution for drops and energy obtained from the model are similar to those measured during shearing experiments. This simple model may be useful to identify failure events linked to force chain failures. Future generalizations of the model that include different types of fiber failure may also allow identification of different types of granular failures that have distinct statistical acoustic emission signatures.

Multi-rater feedback with gap analysis: an innovative means to assess communication skill and self-insight.

PubMed

Calhoun, Aaron W; Rider, Elizabeth A; Peterson, Eleanor; Meyer, Elaine C

2010-09-01

Multi-rater assessment with gap analysis is a powerful method for assessing communication skills and self-insight, and enhancing self-reflection. We demonstrate the use of this methodology. The Program for the Approach to Complex Encounters (PACE) is an interdisciplinary simulation-based communication skills program. Encounters are assessed using an expanded Kalamazoo Consensus Statement Essential Elements Checklist adapted for multi-rater feedback and gap analysis. Data from a representative conversation were analyzed. Likert and forced-choice data with gap analysis are used to assess performance. Participants were strong in Demonstrating Empathy and Providing Closure, and needed to improve Relationship Building, Gathering Information, and understanding the Patient's/Family's Perspective. Participants under-appraised their abilities in Relationship Building, Providing Closure, and Demonstrating Empathy, as well as their overall performance. The conversion of these results into verbal feedback is discussed. We describe an evaluation methodology using multi-rater assessment with gap analysis to assess communication skills and self-insight. This methodology enables faculty to identify undervalued skills and perceptual blind spots, provide comprehensive, data driven, feedback, and encourage reflection. Implementation of graphical feedback forms coupled with one-on-one discussion using the above methodology has the potential to enhance trainee self-awareness and reflection, improving the impact of educational programs. Copyright (c) 2010 Elsevier Ireland Ltd. All rights reserved.

Network-Based Real-time Integrated Fire Detection and Alarm (FDA) System with Building Automation

NASA Astrophysics Data System (ADS)

Anwar, F.; Boby, R. I.; Rashid, M. M.; Alam, M. M.; Shaikh, Z.

2017-11-01

Fire alarm systems have become increasingly an important lifesaving technology in many aspects, such as applications to detect, monitor and control any fire hazard. A large sum of money is being spent annually to install and maintain the fire alarm systems in buildings to protect property and lives from the unexpected spread of fire. Several methods are already developed and it is improving on a daily basis to reduce the cost as well as increase quality. An integrated Fire Detection and Alarm (FDA) systems with building automation was studied, to reduce cost and improve their reliability by preventing false alarm. This work proposes an improved framework for FDA system to ensure a robust intelligent network of FDA control panels in real-time. A shortest path algorithmic was chosen for series of buildings connected by fiber optic network. The framework shares information and communicates with each fire alarm panels connected in peer to peer configuration and declare the network state using network address declaration from any building connected in network. The fiber-optic connection was proposed to reduce signal noises, thus increasing large area coverage, real-time communication and long-term safety. Based on this proposed method an experimental setup was designed and a prototype system was developed to validate the performance in practice. Also, the distributed network system was proposed to connect with an optional remote monitoring terminal panel to validate proposed network performance and ensure fire survivability where the information is sequentially transmitted. The proposed FDA system is different from traditional fire alarm and detection system in terms of topology as it manages group of buildings in an optimal and efficient manner.Introduction

Identification of differentially expressed placental transcripts during multiple gestations in the Eurasian beaver (Castor fiber L.).

PubMed

Lipka, A; Paukszto, L; Majewska, M; Jastrzebski, J P; Myszczynski, K; Panasiewicz, G; Szafranska, B

2017-09-01

The Eurasian beaver is one of the largest rodents that, despite its high impact on the environment, is a non-model species that lacks a reference genome. Characterising genes critical for pregnancy outcome can serve as a basis for identifying mechanisms underlying effective reproduction, which is required for the success of endangered species conservation programs. In the present study, high-throughput RNA sequencing (RNA-seq) was used to analyse global changes in the Castor fiber subplacenta transcriptome during multiple pregnancy. De novo reconstruction of the C. fiber subplacenta transcriptome was used to identify genes that were differentially expressed in placentas (n=5) from two females (in advanced twin and triple pregnancy). Analyses of the expression values revealed 124 contigs with significantly different expression; of these, 55 genes were identified using MegaBLAST. Within this group of differentially expressed genes (DEGs), 18 were upregulated and 37 were downregulated in twins. Most DEGs were associated with the following gene ontology terms: cellular process, single organism process, response to stimulus, metabolic process and biological regulation. Some genes were also assigned to the developmental process, the reproductive process or reproduction. Among this group, four genes (namely keratin 19 (Krt19) and wingless-type MMTV integration site family - member 2 (Wnt2), which were downregulated in twins, and Nik-related kinase (Nrk) and gap junction protein β2 (Gjb2), which were upregulated in twins) were assigned to placental development and nine (Krt19, Wnt2 and integrin α 7 (Itga7), downregulated in twins, and Nrk, gap junction protein β6 (Gjb6), GATA binding protein 6 (Gata6), apolipoprotein A-I (ApoA1), apolipoprotein B (ApoB) and haemoglobin subunit α 1 (HbA1), upregulated in twins) were assigned to embryo development. The results of the present study indicate that the number of fetuses affects the expression profile in the C. fiber subplacental transcriptome. Enhancement of transcriptomic resources for C. fiber will improve understanding of the pathways relevant to proper placental development and successful reproduction.

Asbestos removal in the construction industry. Master's thesis

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

Banks, A.J.

The purpose of this report is to examine the impact of asbestos abatement on the construction industry. It is estimated that the cleanup effort may cost $100 billion over the next twenty five years. More than 733,000 structures, or twenty percent of U. S. commercial and public properties are believed to contain asbestos. Some of the material is in a friable state. This asbestos is crumbling into microscopic fibers that can float in through the air. The use of asbestos was restricted after high doses of its fibers were found to scar lungs, causing cancer and other diseases. Construction businessesmore » use 50 percent of the U. S. supply of asbestos in asbestos cement pipes, sheets, siding shingles, floor tiles, coatings, and sealants. Some 29,000 workers install asbestos insulation during building construction. Other estimates of exposed workers include 20,400 in demolition, 67,800 in abatement, 82,500 in general building renovation, 135,700 doing routine maintenance in buildings, and 183,200 in routine maintenance in general industry. The demand for asbestos removal services exceeds the ability of the industry to supply it safely. Asbestos management and removal are major issues for the construction industry world wide.« less

Local area networking in a radio quiet environment

NASA Astrophysics Data System (ADS)

Childers, Edwin L.; Hunt, Gareth; Brandt, Joseph J.

2002-11-01

The Green Bank facility of the National Radio Astronomy Observatory is spread out over 2,700 acres in the Allegheny Mountains of West Virginia. Good communication has always been needed between the radio telescopes and the control buildings. The National Radio Quiet Zone helps protect the Green Bank site from radio transmissions that interfere with the astronomical signals. Due to stringent Radio Frequency Interference (RFI) requirements, a fiber optic communication system was used for Ethernet transmissions on the site and coaxial cable within the buildings. With the need for higher speed communications, the entire network has been upgraded to use optical fiber with modern Ethernet switches. As with most modern equipment, the implementation of the control of the newly deployed Green Bank Telescope (GBT) depends heavily on TCP/IP. In order to protect the GBT from the commodity Internet, the GBT uses a non-routable network. Communication between the control building Local Area Network (LAN) and the GBT is implemented using a Virtual LAN (VLAN). This configuration will be extended to achieve isolation between trusted local user systems, the GBT, and other Internet users. Legitimate access to the site, for example by remote observers, is likely to be implemented using a virtual private network (VPN).

Selected Bibliography on Fiber-Reinforced Cement and Concrete. Supplement Number 4.

DTIC Science & Technology

1982-08-01

Building Industry," L’Industria Italiana del Cemento , Vol 50, No. 12, Dec 1980, pp 1135-1144. 19. Bartos, P., "Pullout Failure of Fibres Embedded in Cement...Vol 43, No. 11, Nov 1977, pp 561-564. 21. Bassan, M., "Model of Behavior of Fiber-Reinforced Concretes Under Impact Stresses," il Cemento , Vol 74, No...Pastes," il Cemento , Vol 75, No. 3, Jul-Sep 1978, pp 277-284. 210. Mills, R. H., "Age-Embrittlement of Glass-Reinforced Concrete Containing Blastfurance

Design and Manufacture of Conical Shell Structures Using Prepreg Laminates

NASA Astrophysics Data System (ADS)

Khakimova, Regina; Burau, Florian; Degenhardt, Richard; Siebert, Mark; Castro, Saullo G. P.

2016-06-01

The design and manufacture of unstiffened composite conical structures is very challenging, as the variation of the fiber orientations, lay-up and the geometry of the ply pieces have a significant influence on the thickness imperfections and ply angle deviations imprinted to the final part. This paper deals with the manufacture of laminated composite cones through the prepeg/autoclave process. The cones are designed to undergo repetitive buckling tests without accumulating permanent damage. The aim is to define a process that allows the control of fiber angle deviations and the removal of thickness imperfections generated from gaps and overlaps between ply pieces. Ultrasonic scan measurements are used to proof the effectiveness of the proposed method.

Building Energy Management Open Source Software

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

Rahman, Saifur

Funded by the U.S. Department of Energy in November 2013, a Building Energy Management Open Source Software (BEMOSS) platform was engineered to improve sensing and control of equipment in small- and medium-sized commercial buildings. According to the Energy Information Administration (EIA), small- (5,000 square feet or smaller) and medium-sized (between 5,001 to 50,000 square feet) commercial buildings constitute about 95% of all commercial buildings in the U.S. These buildings typically do not have Building Automation Systems (BAS) to monitor and control building operation. While commercial BAS solutions exist, including those from Siemens, Honeywell, Johnsons Controls and many more, they aremore » not cost effective in the context of small- and medium-sized commercial buildings, and typically work with specific controller products from the same company. BEMOSS targets small and medium-sized commercial buildings to address this gap.« less

Yb-doped polarizing fiber

NASA Astrophysics Data System (ADS)

Gillooly, A.; Webb, A. S.; Favero, F. C.; Bouchan, T.; Cooper, L. J.; Read, D.; Hill, M.

2017-02-01

An ytterbium (Yb) doped polarizing fiber is demonstrated. The fiber offers the opportunity to build all-fiber lasers with single polarization output and without the need for free-space polarizing components. Traditional single polarization fiber lasers utilize polarization-maintaining (PM) gain fiber with a single polarization stimulation signal. Whilst this results in an approximation to a single polarization laser, the spontaneous emission from the unstimulated polarization state limits the polarization extinction ratio (PER). The PER is further limited as the stimulated signal is prone to crosstalk. Furthermore, controlling amplitude modulation of the stimulated signal is critical for maximizing the peak power of an optical pulse, particularly for high energy lasers. If light is allowed to leak in to the unstimulated axis it will travel at a different velocity to the stimulated axis and can cross-couple back into the signal axis, creating an interference effect which leads to amplitude modulation on the signal pulse. Single-polarization Yb-doped fiber ensures that light on the fast axis is constantly attenuated; ensuring that light on the unstimulated axis cannot propagate and thus cannot degrade the PER or create amplitude modulation. In this paper we report on, to the best of our knowledge, the first demonstration of a single polarization Yb-doped bowtie optical fiber manufactured using a combination of Modified Chemical Vapor Deposition (MCVD) and rare-earth solution doping technology. The fiber has a single-polarization window of 80nm at the operating wavelength of 1060nm and a PER of >18dB. The fabrication and characterization of the fiber is reported.

Temperature and velocity conditions of air flow in vertical channel of hinged ventilated facade of a multistory building.

NASA Astrophysics Data System (ADS)

Statsenko, Elena; Ostrovaia, Anastasia; Pigurin, Andrey

2018-03-01

This article considers the influence of the building's tallness and the presence of mounting grooved lines on the parameters of heat transfer in the gap of a hinged ventilated facade. A numerical description of the processes occurring in a heat-gravitational flow is given. The average velocity and temperature of the heat-gravitational flow of a structure with open and sealed rusts are determined with unchanged geometric parameters of the gap. The dependence of the parameters influencing the thermomechanical characteristics of the enclosing structure is derived depending on the internal parameters of the system. Physical modeling of real multistory structures is performed by projecting actual parameters onto a reduced laboratory model (scaling).

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.

Characterization and modeling of microstructured chalcogenide fibers for efficient mid-infrared wavelength conversion.

PubMed

Xing, Sida; Grassani, Davide; Kharitonov, Svyatoslav; Billat, Adrien; Brès, Camille-Sophie

2016-05-02

We experimentally demonstrate wavelength conversion in the 2 µm region by four-wave mixing in an AsSe and a GeAsSe chalcogenide photonic crystal fibers. A maximum conversion efficiency of -25.4 dB is measured for 112 mW of coupled continuous wave pump in a 27 cm long fiber. We estimate the dispersion parameters and the nonlinear refractive indexes of the chalcogenide PCFs, establishing a good agreement with the values expected from simulations. The different fiber geometries and glass compositions are compared in terms of performance, showing that GeAsSe is a more suited candidate for nonlinear optics at 2 µm. Building from the fitted parameters we then propose a new tapered GeAsSe PCF geometry to tailor the waveguide dispersion and lower the zero dispersion wavelength (ZDW) closer to the 2 µm pump wavelength. Numerical simulations shows that the new design allows both an increased conversion efficiency and bandwidth, and the generation of idler waves further in the mid-IR regions, by tuning the pump wavelength in the vicinity of the fiber ZDW.

Space-division-multiplexed transmission of 3x3 multiple-input multiple-output wireless signals over conventional graded-index multimode fiber.

PubMed

Lei, Yi; Li, Jianqiang; Fan, Yuting; Yu, Dawei; Fu, Songnian; Yin, Feifei; Dai, Yitang; Xu, Kun

2016-12-12

In this paper, we experimentally demonstrate space-division-multiplexed (SDM) transmission of IEEE 802.11ac-compliant 3-spatial-stream WLAN signals over 3 spatial modes of conventional 50um graded-index (GI) multimode fiber (MMF) employing non-mode-selective 3D-waveguide photonic lantern. Two kinds of scenarios, including fiber-only transmission and fiber-wireless hybrid transmission, were investigated by measuring error vector magnitude (EVM) performance for each stream and condition number (CN) of the channel matrix. The experimental results show that, SDM-based MMF link could offer a CN< 20dB well-conditioned MIMO channel over up to 1km fiber length within 0-6GHz, achieving as low as 2.38%, 2.97% and 2.11% EVM performance for 1km MMF link at 2.4GHz, 5.8GHz, and 200m MMF link followed by 1m air distance at 2.7GHz, respectively. These results indicate the possibility to distribute wireless MIMO signals over existing in-building commercially-available MMFs with enormous cost-saving.

Shifting Gears: Building New Pathways for Low-Skilled Workers to Succeed in the 21st Century Economy

ERIC Educational Resources Information Center

Joyce Foundation, 2013

2013-01-01

The United States faces an increasing gap between the skills possessed by its workforce and those that are necessary to succeed in the 21st century economy. This gap poses a threat to the financial wellbeing of low-skilled American workers and their families and to the nation's long-term economic growth. Recognizing the threat posed by these…

Exposure to PM2.5 in modern office buildings through elemental characterization and oxidative potential

NASA Astrophysics Data System (ADS)

Szigeti, Tamás; Kertész, Zsófia; Dunster, Christina; Kelly, Frank J.; Záray, Gyula; Mihucz, Victor G.

2014-09-01

Fifty samples of indoor and outdoor PM2.5 were collected onto quartz fiber and Teflon membrane filters in five office buildings equipped with heating, ventilation and air-conditioning system for 8 h daily in order to coincide with the work shift of employees. Samples were analyzed for i) mass concentration; ii) elemental concentration; and iii) oxidative potential (OP) through antioxidant depletion. The PM2.5 mass concentration exceeded the annual mean guideline of 10 μg m-3 WHO in 50% of the samples. Indoor and outdoor PM2.5 mass concentrations correlated almost linearly. Proton-induced X-ray emission (PIXE) spectrometry was used for the monitoring of 21 elements. Quantitative determination was achieved in the case of Teflon filters only for Al, Si, S, Cl, K, Ca, Ti, Cr, Mn, Fe and Zn at ng m-3 concentration level. Quartz fiber filters were less adequate for the PIXE measurements due to their greater thickness and filamentary structure. Ca, Cr, Zn and Ti had generally higher concentration (mg g-1) indoors. Indoor/outdoor (I/O) OP values were higher than one in 14% and 57% of the samples in the case of ascorbate and reduced glutathione (GSH), respectively. Spatial and temporal variations of OP were observed across the office buildings. The I/O ratios for OP, Cr and Zn concentrations in the case of GSH were higher for three buildings. Significant relationship was observed between GSH oxidation and Cr and Zn concentrations. Thus, employees were exposed to a higher extent to reactive oxygen species in three buildings.

[Identification of varieties of textile fibers by using Vis/NIR infrared spectroscopy technique].

PubMed

Wu, Gui-Fang; He, Yong

2010-02-01

The aim of the present paper was to provide new insight into Vis/NIR spectroscopic analysis of textile fibers. In order to achieve rapid identification of the varieties of fibers, the authors selected 5 kinds of fibers of cotton, flax, wool, silk and tencel to do a study with Vis/NIR spectroscopy. Firstly, the spectra of each kind of fiber were scanned by spectrometer, and principal component analysis (PCA) method was used to analyze the characteristics of the pattern of Vis/NIR spectra. Principal component scores scatter plot (PC1 x PC2 x PC3) of fiber indicated the classification effect of five varieties of fibers. The former 6 principal components (PCs) were selected according to the quantity and size of PCs. The PCA classification model was optimized by using the least-squares support vector machines (LS-SVM) method. The authors used the 6 PCs extracted by PCA as the inputs of LS-SVM, and PCA-LS-SVM model was built to achieve varieties validation as well as mathematical model building and optimization analysis. Two hundred samples (40 samples for each variety of fibers) of five varieties of fibers were used for calibration of PCA-LS-SVM model, and the other 50 samples (10 samples for each variety of fibers) were used for validation. The result of validation showed that Vis/NIR spectroscopy technique based on PCA-LS-SVM had a powerful classification capability. It provides a new method for identifying varieties of fibers rapidly and real time, so it has important significance for protecting the rights of consumers, ensuring the quality of textiles, and implementing rationalization production and transaction of textile materials and its production.

Southern hardwood growth-use gap closing fast as inventories peak

Treesearch

William A. Bechtold

1989-01-01

The use of hardwood for pulp and paper furnish and other fiber products is steadily increasing in the U.S. Pulpwood now accounts for half of all hardwood roundwood currently harvested for industrial timber products in the Southeast. In addition to domestic consumption, hardwood exports to Europe and Asia are also expanding, and good portion of these are shipped from...

A spaceworthy ADR - Recent developments. [Adiabatic Demagnetization Refrigerator for X ray spectrometer

NASA Technical Reports Server (NTRS)

Serlemitsos, Aristides T.; Warner, Brent A.; Sansebastian, Marcelino; Kunes, Evan

1990-01-01

Recent developments concerning the performance and reliability of a spaceworthy adiabatic demagnetization refrigerator (ADR) for the AXAF X-ray spectrometer are considered. They include a procedure for growing the salt pill around a harness made up of 6080 gold-plated copper wires, a totally modular gas gap heat switch, and a suspension system utilizing Kevlar fibers.

In-situ thermography of automated fiber placement parts

NASA Astrophysics Data System (ADS)

Gregory, Elizabeth D.; Juarez, Peter D.

2018-04-01

Automated fiber placement (AFP) provides precision and repeatable manufacturing of both simple and complex geometry composite parts. However, AFP also introduces the possibility for unique flaws such as overlapping tows, gaps between tows, tow twists, lack of layer adhesion and foreign object debris. These types of flaws can all result in a significant loss of performance in the final part. The current inspection method for these flaws is a costly and time intensive visual inspection of each ply layer. This work describes some initial efforts to incorporate thermal inspection on the AFP head and analysis of the data to identify the previously mentioned flaws. Previous bench-top laboratory experiments demonstrated that laps, gaps, and twists were identified from a thermal image. The AFP head uses an on- board lamp to preheat the surface of the part during layup to increase ply consolidation. The preheated surface is used as a thermal source to observe the state of the new material after compaction. We will present data collected with the Integrated Structural Assembly of Advanced Composites (ISAAC) AFP machine at Langley Research Center showing that changes to the temperature profile is sufficient for identifying all types of flaws.

Optical Fiber Sensors for Advanced Civil Structures

NASA Astrophysics Data System (ADS)

de Vries, Marten Johannes Cornelius

1995-01-01

The objective of this dissertation is to develop, analyze, and implement optical fiber-based sensors for the nondestructive quantitative evaluation of advanced civil structures. Based on a comparative evaluation of optical fiber sensors that may be used to obtain quantitative information related to physical perturbations in the civil structure, the extrinsic Fabry-Perot interferometric (EFPI) optical fiber sensor is selected as the most attractive sensor. The operation of the EFPI sensor is explained using the Kirchhoff diffraction approach. As is shown in this dissertation, this approach better predicts the signal-to-noise ratio as a function of gap length than methods employed previously. The performance of the optical fiber sensor is demonstrated in three different implementations. In the first implementation, performed with researchers in the Civil Engineering Department at the University of Southern California in Los Angeles, optical fiber sensors were used to obtain quantitative strain information from reinforced concrete interior and exterior column-to-beam connections. The second implementation, performed in cooperation with researchers at the United States Bureau of Mines in Spokane, Washington, used optical fiber sensors to monitor the performance of roof bolts used in mines. The last implementation, performed in cooperation with researchers at the Turner-Fairbanks Federal Highway Administration Research Center in McLean, Virginia, used optical fiber sensors, attached to composite prestressing strands used for reinforcing concrete, to obtain absolute strain information. Multiplexing techniques including time, frequency and wavelength division multiplexing are briefly discussed, whereas the principles of operation of spread spectrum and optical time domain reflectometery (OTDR) are discussed in greater detail. Results demonstrating that spread spectrum and OTDR techniques can be used to multiplex optical fiber sensors are presented. Finally, practical considerations that have to be taken into account when implementing optical fiber sensors into a civil structure environment are discussed, and possible solutions to some of these problems are proposed.

High-brightness 800nm fiber-coupled laser diodes

NASA Astrophysics Data System (ADS)

Berk, Yuri; Levy, Moshe; Rappaport, Noam; Tessler, Renana; Peleg, Ophir; Shamay, Moshe; Yanson, Dan; Klumel, Genadi; Dahan, Nir; Baskin, Ilya; Shkedi, Lior

2014-03-01

Fiber-coupled laser diodes have become essential sources for fiber laser pumping and direct energy applications. Single emitters offer reliable multi-watt output power from a 100 m lateral emission aperture. By their combination and fiber coupling, pump powers up to 100 W can be achieved from a low-NA fiber pigtail. Whilst in the 9xx nm spectral range the single emitter technology is very mature with <10W output per chip, at 800nm the reliable output power from a single emitter is limited to 4 W - 5 W. Consequently, commercially available fiber coupled modules only deliver 5W - 15W at around 800nm, almost an order of magnitude down from the 9xx range pumps. To bridge this gap, we report our advancement in the brightness and reliability of 800nm single emitters. By optimizing the wafer structure, laser cavity and facet passivation process we have demonstrated QCW device operation up to 19W limited by catastrophic optical damage to the 100 μm aperture. In CW operation, the devices reach 14 W output followed by a reversible thermal rollover and a complete device shutdown at high currents, with the performance fully rebounded after cooling. We also report the beam properties of our 800nm single emitters and provide a comparative analysis with the 9xx nm single emitter family. Pump modules integrating several of these emitters with a 105 μm / 0.15 NA delivery fiber reach 35W in CW at 808 nm. We discuss the key opto-mechanical parameters that will enable further brightness scaling of multi-emitter pump modules.

A new generation of ultra-dense optical I/O for silicon photonics

NASA Astrophysics Data System (ADS)

Wlodawski, Mitchell S.; Kopp, Victor I.; Park, Jongchul; Singer, Jonathan; Hubner, Eric E.; Neugroschl, Daniel; Chao, Norman; Genack, Azriel Z.

2014-03-01

In response to the optical packaging needs of a rapidly growing silicon photonics market, Chiral Photonics, Inc. (CPI) has developed a new generation of ultra-dense-channel, bi-directional, all-optical, input/output (I/O) couplers that bridge the data transport gap between standard optical fibers and photonic integrated circuits. These couplers, called Pitch Reducing Optical Fiber Arrays (PROFAs), provide a means to simultaneously match both the mode field and channel spacing (i.e. pitch) between an optical fiber array and a photonic integrated circuit (PIC). Both primary methods for optically interfacing with PICs, via vertical grating couplers (VGCs) and edge couplers, can be addressed with PROFAs. PROFAs bring the signal-carrying cores, either multimode or singlemode, of many optical fibers into close proximity within an all-glass device that can provide low loss coupling to on-chip components, including waveguides, gratings, detectors and emitters. Two-dimensional (2D) PROFAs offer more than an order of magnitude enhancement in channel density compared to conventional one-dimensional (1D) fiber arrays. PROFAs can also be used with low vertical profile solutions that simplify optoelectronic packaging while reducing PIC I/O real estate usage requirements. PROFA technology is based on a scalable production process for microforming glass preform assemblies as they are pulled through a small oven. An innovative fiber design, called the "vanishing core," enables tailoring the mode field along the length of the PROFA to meet the coupling needs of disparate waveguide technologies, such as fiber and onchip. Examples of single- and multi-channel couplers fabricated using this technology will be presented.

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

Farrar, Sara; Rothgeb, Stacey; Polly, Ben

The U.S. Department of Energy (DOE) Building America Program enables the transformation of the U.S. housing industry to achieve energy savings through energy-efficient, high-performance homes with improved durability, comfort, and health for occupants. Building America bridges the gap between the development of emerging technologies and the adoption of codes and standards by engaging industry partners in applied research, development, and demonstration of high-performance solutions.

On the photonic implementation of universal quantum gates, bell states preparation circuit and quantum LDPC encoders and decoders based on directional couplers and HNLF.

PubMed

Djordjevic, Ivan B

2010-04-12

The Bell states preparation circuit is a basic circuit required in quantum teleportation. We describe how to implement it in all-fiber technology. The basic building blocks for its implementation are directional couplers and highly nonlinear optical fiber (HNLF). Because the quantum information processing is based on delicate superposition states, it is sensitive to quantum errors. In order to enable fault-tolerant quantum computing the use of quantum error correction is unavoidable. We show how to implement in all-fiber technology encoders and decoders for sparse-graph quantum codes, and provide an illustrative example to demonstrate this implementation. We also show that arbitrary set of universal quantum gates can be implemented based on directional couplers and HNLFs.

Fiber feed for the CFHT Gecko spectrograph

NASA Astrophysics Data System (ADS)

Baudrand, Jacques; Vitry, Rene

2000-08-01

Motivated by a strong concern to keep maintenance work as low as possible the direction of the CFHT had for some times contemplated the possibility to replace the original mirror train f/20 focus feeding their Gecko High Resolution Coude Spectrograph by a more convenient fiber link coupled to the f/8 Cassegrain focus. A decision supporting that idea was ultimately taken two years ago and our group at the OPM was contacted to build such a system according to precise specifications. This telescope facility, baptized CAFÉ for Cassegrain Fiber Environment, has now arrived to near completion and we are able to present here its main characteristics and the technical solutions that were adopted to meet the CFHT requirements and to provide the system with the best performances in terms of robustness and efficiency.

Materials and structures/ACEE

NASA Technical Reports Server (NTRS)

1981-01-01

Light weight composites made from graphite fibers, glass, or man made materials held in an epoxy matrix, and their application to airframe design are reviewed. The Aircraft Energy Efficiency program is discussed. Characteristics of composites, acceptable risks, building parts and confidence, and aeroelastic tailoring are considered.

Exercise Balikatan 2012 Technology Insertion Quicklook Report

DTIC Science & Technology

2012-05-15

expanded polystyrene panels covered with a thin layer of cement, sand, fiberglass, and other additives. A permanent 200 sq ft building with windows... Expanded Polystyrene 1.5# density pre-cut panels and GFRC -Glass Fiber Reinforced Concrete Structural coating (Fiberglass Mesh, Portland Cement, Silica

29 CFR 1910.331 - Scope.

Code of Federal Regulations, 2010 CFR

2010-07-01

... or no such training) working on, near, or with the following installations: (1) Premises wiring. Installations of electric conductors and equipment within or on buildings or other structures, and on other... wiring. Installations of other outside conductors on the premises. (4) Optical fiber cable. Installations...

Monoculture and polyculture: Kenaf (Hibiscus cannabinus) and sunn hemp (Crotalaria juncea)

USDA-ARS?s Scientific Manuscript database

Kenaf (Hibiscus cannabinus L.) and sunn hemp (Crotalaria juncea L.) are fast growing summer annual crops with numerous commercial applications (fibers, biofuels, bioremediation, paper pulp, building materials, cover crops, and livestock forages). Field research was conducted in southeast Oklahoma (...

Kenaf (Hibiscus cannabinus) and sunn hemp (Crotalaria juncea): Monoculture and polyculture production

USDA-ARS?s Scientific Manuscript database

Kenaf (Hibiscus cannabinus L.) and sunn hemp (Crotalaria juncea L.) are fast growing summer annual crops with numerous commercial applications (fibers, biofuels, bioremediation, paper pulp, building materials, cover crops, and livestock forages). Field research was conducted in southeast Oklahoma (...

All Optical Solution for Free Space Optics Point to Point Links

NASA Astrophysics Data System (ADS)

Hirayama, Daigo

Optical network systems are quickly replacing electrical network systems. Optical systems provide better bandwidth, faster data rates, better security to networks, and are less susceptible to noise. Free Space Optics (systems) still rely on numerous electrical systems such as the modulation and demodulation systems to convert optical signals to electrical signals for the transmitting laser. As the concept of the entirely optical network becomes more realizable, the electrical components of the FSO system will become a hindrance to communications. The focus of this thesis is to eliminate the electrical devices for the FSO point to point links by replacing them with optical devices. The concept is similar to an extended beam connector. However, where an extended beam connector deals with a gap of a few millimeters, my focus looks at distances from 100 meters to one kilometer. The aim is to achieve a detectable signal of 1nW at a distance of 500 meters at a wavelength of 1500-1600nm. This leads to application in building to building links and mobile networks. The research examines the design of the system in terms of generating the wave, the properties of the fiber feeding the wave, and the power necessary to achieve a usable distance. The simulation is executed in Code V by Synopsys, which is an industry standard to analyze optical systems. A usable device with a range of around 500m was achieved with an input power of 1mW. The approximations of the phase function resulted in some aberrations to the profile of the beam, but were not very detrimental to the function of the device. The removal of electrical devices from a FSO point to point link decreased the power used to establish the link and decreased the cost.

Smart textiles for tactile sensing and energy storage

NASA Astrophysics Data System (ADS)

Gorgutsa, Stepan

During my master's I have mainly worked on two subjects in the research area of electroactive smart textiles. My first project involved building a touch sensitive textile pad using original home-made all-polymer soft capacitor fibers. The capacitor fibers featuring relatively high capacitance and resistance were fabricated using fiber drawing technique. For the ease of connectorization, a thin copper wire was integrated into the fiber core during drawing procedure. Soft-capacitor fibers have a typical capacitance per unit length of 69 nF/m, and a typical resistivity parameter of 5 kΩ·m. Our measurements and theoretical modeling show that the fiber capacitance is a very stable, geometry defined parameter independent of the fiber diameter, and fiber fabrication parameters. In contrast, fiber resistivity has a very strong positive temperature coefficient, it is highly sensitive to stretching, and it is strongly dependent on the fiber drawing parameters. Next, an individual capacitor fiber was demonstrated to act as a slide sensor that allows determining the touch position along its length by measuring the fiber AC response at a single point at the fiber surface. Electrical response of such a sensor was described by the RC ladder model, with the modelling data in excellent agreement with experimental observations. Developed capacitor fibers are soft, small diameter, lightweight and do not use liquid electrolytes, thus they are ideally suited for the integration into textile products. At the end of the chapter, we have demonstrated that by weaving a one dimensional array of capacitor fibers (in parallel to each other) a fully woven 2D touchpad sensor could be build. Performance of a touchpad sensor was then characterised and the absence of the inter-channel crosstalk was confirmed. We also note that a 2D touchpad has a partial multi-touch functionality. My second project involved assembly of flexible and stretchable Li-ion batteries, their integration into a textile, and their electric characterization in a view of smart textile applications. The chemistry for the battery was developed by my colleague Y. Liu who has combined the relatively conventional Li battery materials including LiFePO4 cathode, Li4Ti 5O12 anode and PEO solid electrolyte into a non-conventional soft electrochemical battery system. I have experimentally demonstrated that flexible batteries can be first cast as sheets, and then cut into thin strips, and finally integrated into textile using conventional weaving techniques. The electrochemical performance of the film batteries was extensively characterized and found to be poorer compared to the performance of batteries based on the powder electrodes and liquid electrolytes. At the same time, cycling performance of the solid film batteries was stable, and together with their soft leather-like feel and appearance, this makes such batteries well suitable for smart textile applications. Although operating voltage of a single flexible battery is relatively low (˜0.3V), nevertheless, when several of them are connected in series, the net voltage can be large enough for practical applications. Finally, as a demonstrator of the technology I have tested a textile battery comprising 8 flexible battery strips woven together and connectorized in series to power up a 3V LED over several hours.

Mechanisms of myocardial capture and temporal excitable gap during spiral wave reentry in a bidomain model.

PubMed

Ashihara, Takashi; Namba, Tsunetoyo; Ikeda, Takanori; Ito, Makoto; Nakazawa, Kazuo; Trayanova, Natalia

2004-02-24

Recent studies have demonstrated that regional capture during cardiac fibrillation is associated with an elevated capture threshold. It is typically assumed that the temporal excitable gap (capture window) during fibrillation reflects the size of the spatial excitable gap (excitable tissue between fibrillation waves). Because capture threshold is high, virtual electrode polarization is expected to be involved in the process. However, little is known about the underlying mechanisms of myocardial capture during fibrillation. To clarify these issues, we conducted altogether 3168 simulations of single spiral wave capture in a bidomain sheet. Unipolar stimuli of strengths 4, 8, 16, and 24 mA and 2-ms duration were delivered at 99 locations in the sheet. We found that cathode-break rather than cathode-make excitation was the dominant mechanism of myocardial capture. When the stimulation site was located diagonally with respect to the core (upper left or lower right if the spiral wave rotates counterclockwise), the cathode-break excitation easily invaded the spatial excitable gap and resulted in a successful capture as a result of the formation of virtual anodes in the direction of the myocardial fibers. Thus, the spatial distribution of the temporal excitable gap did not reflect the spatial excitable gap. The areas exhibiting wide temporal excitable gaps were areas in which the cathode-break excitation wave fronts easily invaded the spatial excitable gap via the virtual anodes. This study provides mechanistic insight into myocardial capture.

Excitation-calcium release uncoupling in aged single human skeletal muscle fibers.

PubMed

Delbono, O; O'Rourke, K S; Ettinger, W H

1995-12-01

The biological mechanisms underlying decline in muscle power and fatigue with age are not completely understood. The contribution of alterations in the excitation-calcium release coupling in single muscle fibers was explored in this work. Single muscle fibers were voltage-clamped using the double Vaseline gap technique. The samples were obtained by needle biopsy of the vastus lateralis (quadriceps) from 9 young (25-35 years; 25.9 +/- 9.1; 5 female and 4 male) and 11 old subjects (65-75 years; 70.5 +/- 2.3; 6 f, 5 m). Data were obtained from 36 and 39 fibers from young and old subjects, respectively. Subjects included in this study had similar physical activity. Denervated and slow-twitch muscle fibers were excluded from this study. A significant reduction of maximum charge movement (Qmax) and DHP-sensitive Ca current were recorded in muscle fibers from the 65-75 group. Qmax values were 7.6 +/- 0.9 and 3.2 +/- 0.3 nC/muF for young and old muscle fibers, respectively (P < 0.01). No evidences of charge inactivation or interconversion (charge 1 to charge 2) were found. The peak Ca current was (-)4.7 +/- 0.08 and (-)2.15 +/- 0.11 muA/muF for young and old fibers, respectively (P < 0.01). The peak calcium transient studied with mag-fura-2 (400 microM) was 6.3 +/- 0.4 microM and 4.2 +/- 0.3 microM for young and old muscle fibers, respectively. Caffeine (0.5 mM) induced potentiation of the peak calcium transient in both groups. The decrease in the voltage-/Ca-dependent Ca release ratio in old fibers (0.18 +/- 0.02) compared to young fibers (0.47 +/- 0.03) (P < 0.01), was recorded in the absence of sarcoplasmic reticulum calcium depletion. These data support a significant reduction of the amount of Ca available for triggering mechanical responses in aged skeletal muscle and, the reduction of Ca release is due to DHPR-ryanodine receptor uncoupling in fast-twitch fibers. These alterations can account, at least partially for the skeletal muscle function impairment associated with aging.

Early Experience in Implementation of a Learning Assessment Toolkit in the AOTrauma Geriatric Fracture Course

PubMed Central

O’Malley, Natasha T.; Cunningham, Michael; Leung, Frankie; Blauth, Michael; Kates, Stephen L.

2011-01-01

Background: Surgical education is continually expanding to encompass new techniques and technologies. It is vital that educational activity is directed at gaps in knowledge and ability to improve the quality of learning. Aim: The aim of this study is to describe a published learning assessment toolkit when applied to participants attending AOTrauma Orthogeriatric Fracture courses. Methods: Precourse, participants received a questionnaire covering 10 competencies to assess knowledge gaps and a 20-question clinical knowledge test. The knowledge gap between perceived and desired knowledge was correlated with clinical knowledge test results to help course faculty focus the course curriculum to meet identified educational needs. A commitment to change survey was also administered. Results: Over 3 courses, 48% of registered attendees responded to the precourse survey, 44.5% responded postcourse. The precourse gap scores were generally highest for 2 competencies (“address secondary prevention,” “build a system of care”) indicating a higher level of motivation to learn in these topics and lowest for a variety of competencies (eg. “restore function early,” “co-manage patient care in the US surgeons group”) indicating lower motivation to learn in these competencies. These precourse gap scores guided adaptations in the course structure. Postcourse gaps were reduced in the 4 cohorts. Large improvements were seen in “Address secondary prevention” and “Build a system of care” in many of the cohorts. Competencies with the lowest precourse knowledge test scores were noted in each cohort. Where low pretest scores were noted, it highlighted the need for faculty to put appropriate emphasis on these topics in the delivery of the course content. Conclusion: The technique of evaluating and identifying gaps in knowledge and ability allows course designers to focus on areas of deficits. Measurable success was shown with a subjectively decreased gap score and objectively improved clinical knowledge, as demonstrated by improved test results after course completion. PMID:23569686

Bioinspired design and macroscopic assembly of poly(vinyl alcohol)-coated graphene into kilometers-long fibers

NASA Astrophysics Data System (ADS)

Kou, Liang; Gao, Chao

2013-05-01

Nacre is characterized by its excellent mechanical performance due to the well-recognized ``brick and mortar'' structure. Many efforts have been applied to make nacre-mimicking materials, but it is still a big challenge to realize their continuous production. Here, we prepared sandwich-like building blocks of poly(vinyl alcohol) (PVA)-coated graphene, and achieved high-nanofiller-content kilometers-long fibers by continuous wet-spinning assembly technology. The fibers have a strict ``brick and mortar'' layered structure, with graphene sheet as rigid brick and PVA as soft mortar. The mortar thickness can be precisely tuned from 2.01 to 3.31 nm by the weight feed ratio of PVA to graphene, as demonstrated by both atomic force microscopy and X-ray diffraction measurements. The mechanical strength of the nacre-mimicking fibers increases with increasing the content of PVA, and it rises gradually from 81 MPa for the fiber with 53.1 wt% PVA to 161 MPa for the fiber with 65.8 wt% PVA. The mechanical performance of our fibers was independent of the molecular weight (MW) of PVA in the wide range of 2-100 kDa, indicating that low MW polymers can also be used to make strong nanocomposites. The tensile stress of fibers immersed in PVA 5 wt% solution reached ca. 200 MPa, surpassing the values of nacre and most of other nacre-mimicking materials. The nacre-mimicking fibers are highly electrically conductive (~350 S m-1) after immersing in hydroiodic acid, enabling them to connect a circuit to illuminate an LED lamp.Nacre is characterized by its excellent mechanical performance due to the well-recognized ``brick and mortar'' structure. Many efforts have been applied to make nacre-mimicking materials, but it is still a big challenge to realize their continuous production. Here, we prepared sandwich-like building blocks of poly(vinyl alcohol) (PVA)-coated graphene, and achieved high-nanofiller-content kilometers-long fibers by continuous wet-spinning assembly technology. The fibers have a strict ``brick and mortar'' layered structure, with graphene sheet as rigid brick and PVA as soft mortar. The mortar thickness can be precisely tuned from 2.01 to 3.31 nm by the weight feed ratio of PVA to graphene, as demonstrated by both atomic force microscopy and X-ray diffraction measurements. The mechanical strength of the nacre-mimicking fibers increases with increasing the content of PVA, and it rises gradually from 81 MPa for the fiber with 53.1 wt% PVA to 161 MPa for the fiber with 65.8 wt% PVA. The mechanical performance of our fibers was independent of the molecular weight (MW) of PVA in the wide range of 2-100 kDa, indicating that low MW polymers can also be used to make strong nanocomposites. The tensile stress of fibers immersed in PVA 5 wt% solution reached ca. 200 MPa, surpassing the values of nacre and most of other nacre-mimicking materials. The nacre-mimicking fibers are highly electrically conductive (~350 S m-1) after immersing in hydroiodic acid, enabling them to connect a circuit to illuminate an LED lamp. Electronic supplementary information (ESI) available: More AFM and SEM images and electrical conductivities of CRG@PVA with different feed ratios, FTIR spectra, Raman and XPS results of GO, CRG and CRG@PVA, SEM images of CRG@PVA fibers with different diameters, SEM images and conductivity of CRG@PVA fibers with different MW of PVA, the tensile curve of CRG@PVA paper, and videos of graphene knot and spring. See DOI: 10.1039/c3nr00455d

Increasing the computational efficient of digital cross correlation by a vectorization method

NASA Astrophysics Data System (ADS)

Chang, Ching-Yuan; Ma, Chien-Ching

2017-08-01

This study presents a vectorization method for use in MATLAB programming aimed at increasing the computational efficiency of digital cross correlation in sound and images, resulting in a speedup of 6.387 and 36.044 times compared with performance values obtained from looped expression. This work bridges the gap between matrix operations and loop iteration, preserving flexibility and efficiency in program testing. This paper uses numerical simulation to verify the speedup of the proposed vectorization method as well as experiments to measure the quantitative transient displacement response subjected to dynamic impact loading. The experiment involved the use of a high speed camera as well as a fiber optic system to measure the transient displacement in a cantilever beam under impact from a steel ball. Experimental measurement data obtained from the two methods are in excellent agreement in both the time and frequency domain, with discrepancies of only 0.68%. Numerical and experiment results demonstrate the efficacy of the proposed vectorization method with regard to computational speed in signal processing and high precision in the correlation algorithm. We also present the source code with which to build MATLAB-executable functions on Windows as well as Linux platforms, and provide a series of examples to demonstrate the application of the proposed vectorization method.

Tow-Steered Panels With Holes Subjected to Compression or Shear Loads

NASA Technical Reports Server (NTRS)

Jegley, Dawn C.; Tatting, Brian F.; Guerdal, Zafer

2005-01-01

Tailoring composite laminates to vary the fiber orientations within a fiber layer of a laminate to address non-uniform stress states and provide structural advantages such as the alteration of principal load paths has potential application to future low-cost, light-weight structures for commercial transport aircraft. Evaluation of this approach requires the determination of the effectiveness of stiffness tailoring through the use of curvilinear fiber paths in flat panels including the reduction of stress concentrations around the holes and the increase in load carrying capability. Panels were designed through the use of an optimization code using a genetic algorithm and fabricated using a tow-steering approach. Manufacturing limitations, such as the radius of curvature of tows the machine could support, avoidance of wrinkling of fibers and minimization of gaps between fibers were considered in the design process. Variable stiffness tow-steered panels constructed with curvilinear fiber paths were fabricated so that the design methodology could be verified through experimentation. Finite element analysis where each element s stacking sequence was accurately defined is used to verify the behavior predicted based on the design code. Experiments on variable stiffness flat panels with central circular holes were conducted with the panels loaded in axial compression or shear. Tape and tow-steered panels are used to demonstrate the buckling, post-buckling and failure behavior of elastically tailored panels. The experimental results presented establish the buckling performance improvements attainable by elastic tailoring of composite laminates.

Monolithic multi-color light emission/detection device

DOEpatents

Wanlass, M.W.

1995-02-21

A single-crystal, monolithic, tandem, multi-color optical transceiver device is described, including (a) an InP substrate having upper and lower surfaces, (b) a first junction on the upper surface of the InP substrate, (c) a second junction on the first junction. The first junction is preferably GaInAsP of defined composition, and the second junction is preferably InP. The two junctions are lattice matched. The second junction has a larger energy band gap than the first junction. Additional junctions having successively larger energy band gaps may be included. The device is capable of simultaneous and distinct multi-color emission and detection over a single optical fiber. 5 figs.

Development of SiC Large Tapered Crystal Growth

NASA Technical Reports Server (NTRS)

Neudeck, Phil

2011-01-01

Research Focus Area: Power Electronics, Temperature Tolerant Devices. Demonstrate initial feasibility of totally new "Large Tapered Crystal" (LTC) process for growing vastly improved large-diameter wide-band gap wafers. Addresses Targets: The goal of this research is to experimentally investigate and demonstrate feasibility of the key unproven LTC growth processes in SiC. Laser-assisted growth of long SiC fiber seeds. Radial epitaxial growth enlargement of seeds into large SiC boules. Uniqueness and Impacts open a new technology path to large-diameter SiC and GaN wafers with 1000-fold defect density improvement at 2-4 fold lower cost. Leapfrog improvement in wide band gap power device capability and cost.

Concentric ring flywheel with hooked ring carbon fiber separator/torque coupler

DOEpatents

Kuklo, Thomas C.

1999-01-01

A concentric ring flywheel with expandable separators, which function as torque couplers, between the rings to take up the gap formed between adjacent rings due to differential expansion between different radius rings during rotation of the flywheel. The expandable separators or torque couplers include a hook-like section at an upper end which is positioned over an inner ring and a shelf-like or flange section at a lower end onto which the next adjacent outer ring is positioned. As the concentric rings are rotated the gap formed by the differential expansion there between is partially taken up by the expandable separators or torque couplers to maintain torque and centering attachment of the concentric rings.

An Objective Measurement of the Build-Up of Auditory Streaming and of Its Modulation by Attention

ERIC Educational Resources Information Center

Thompson, Sarah K.; Carlyon, Robert P.; Cusack, Rhodri

2011-01-01

Three experiments studied auditory streaming using sequences of alternating "ABA" triplets, where "A" and "B" were 50-ms tones differing in frequency by [delta]f semitones and separated by 75-ms gaps. Experiment 1 showed that detection of a short increase in the gap between a B tone and the preceding A tone, imposed on one ABA triplet, was better…

Value Focused Thinking for Nation Building in Afghanistan: A Regional Perspective

DTIC Science & Technology

2012-03-01

Force Instructions/ Orders). Using existing policy documents is known as the “gold standard” and yields the most defendable final decisions. They are...Integrated Gap , characterized by unstable leadership and absence from international trade. The Core can be sub-divided into Old Core (North America...Western Europe, Japan, and Australia) and New Core (China, India, South Africa, Brazil, Argentina, Chile and Russia). The Disconnected Gap includes the

Feasibility study for distributed dose monitoring in ionizing radiation environments with standard and custom-made optical fibers

NASA Astrophysics Data System (ADS)

Van Uffelen, Marco; Berghmans, Francis; Brichard, Benoit; Borgermans, Paul; Decréton, Marc C.

2002-09-01

Optical fibers stimulate much interest since many years for their potential use in various nuclear environments, both for radiation tolerant and EMI-free data communication as well as for distributed sensing. Besides monitoring temperature and stress, measuring ionizing doses with optical fibers is particularly essential in applications such as long-term nuclear waste disposal monitoring, and for real-time aging monitoring of power and signal cables installed inside a reactor containment building. Two distinct options exist to perform optical fiber dosimetry. First, find an accurate model for a restricted application field that accounts for all the parameters that influence the radiation response of a standard fiber, or second, develop a dedicated fiber with a response that will solely depend on the deposited energy. Using various models presented in literature, we evaluate both standard commercially available and custom-made optical fibers under gamma radiation, particularly for distributed dosimetry applications with an optical time domain reflectometer (OTDR). We therefore present the radiation induced attenuation at near-infrared telecom wavelengths up to MGy total dose levels, with dose rates ranging from about 1 Gy/h up to 1 kGy/h, whereas temperature was raised step-wise from 25 °C to 85 °C. Our results allow to determine and compare the practical limitations of distributed dose measurements with both fiber types in terms of temperature sensitivity, dose estimation accuracy and spatial resolution.

RH-LLW Disposal Facility Project CD-2/3 to Design/Build Proposal Reconciliation Report

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

Annette L. Schafer

2012-06-01

A reconciliation plan was developed and implemented to address potential gaps and responses to gaps between the design/build vendor proposals and the Critical Decision-2/3 approval request package for the Remote-Handled Low Level Waste Disposal Facility Project. The plan and results of the plan implementation included development of a reconciliation team comprised of subject matter experts from Battelle Energy Alliance and the Department of Energy Idaho Operations Office, identification of reconciliation questions, reconciliation by the team, identification of unresolved/remaining issues, and identification of follow-up actions and subsequent approvals of responses. The plan addressed the potential for gaps to exist in themore » following areas: • Department of Energy Order 435.1, “Radioactive Waste Management,” requirements, including the performance assessment, composite analysis, monitoring plan, performance assessment/composite analysis maintenance plan, and closure plan • Environmental assessment supporting the National Environmental Policy Act • Nuclear safety • Safeguards and security • Emplacement operations • Requirements for commissioning • General project implementation. The reconciliation plan and results of the plan implementation are provided in a business-sensitive project file. This report provides the reconciliation plan and non-business sensitive summary responses to identified gaps.« less

para-Azaquinodimethane: A Compact Quinodimethane Variant as an Ambient Stable Building Block for High-Performance Low Band Gap Polymers

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

Liu, Xuncheng; He, Bo; Anderson, Christopher L.

Quinoidal structures incorporating expanded para-quinodimethane (p-QM) units have garnered great interest as functional organic electronic, optical, and magnetic materials. The direct use of the compact p-QM unit as an electronic building block, however, has been inhibited by the high reactivity conveyed by its biradical character. Herein, we introduce a stable p-QM variant, namely p-azaquinodimethane (p-AQM), that incorporates nitrogen atoms in the central ring and alkoxy substituents on the periphery to increase the stability of the quinoidal structure. The succinct synthesis from readily available precursors leads to regio- and stereospecific p-AQMs that can be readily integrated into the backbone of conjugatedmore » polymers. The quinoidal character of the p-AQM unit endows the resulting polymers with narrow band gaps and high carrier transport mobilities. The study of a series of copolymers employing different numbers of thiophene units revealed an unconventional trend in band gaps, which is distinct from the widely adopted donor-acceptor approach to tuning the band gaps of conjugated polymers. Theoretical calculations have shed light on the nature of this trend, which may provide a unique class of conjugated polymers with promising optical and electronic properties.« less

para-Azaquinodimethane: A Compact Quinodimethane Variant as an Ambient Stable Building Block for High-Performance Low Band Gap Polymers

DOE PAGES

Liu, Xuncheng; He, Bo; Anderson, Christopher L.; ...

2017-05-24

Quinoidal structures incorporating expanded para-quinodimethane (p-QM) units have garnered great interest as functional organic electronic, optical, and magnetic materials. The direct use of the compact p-QM unit as an electronic building block, however, has been inhibited by the high reactivity conveyed by its biradical character. Herein, we introduce a stable p-QM variant, namely p-azaquinodimethane (p-AQM), that incorporates nitrogen atoms in the central ring and alkoxy substituents on the periphery to increase the stability of the quinoidal structure. The succinct synthesis from readily available precursors leads to regio- and stereospecific p-AQMs that can be readily integrated into the backbone of conjugatedmore » polymers. The quinoidal character of the p-AQM unit endows the resulting polymers with narrow band gaps and high carrier transport mobilities. The study of a series of copolymers employing different numbers of thiophene units revealed an unconventional trend in band gaps, which is distinct from the widely adopted donor-acceptor approach to tuning the band gaps of conjugated polymers. Theoretical calculations have shed light on the nature of this trend, which may provide a unique class of conjugated polymers with promising optical and electronic properties.« less

Applying fiber optical methods for toxicological testing in vitro

NASA Astrophysics Data System (ADS)

Maerz, Holger K.; Buchholz, Rainer; Emmrich, Frank; Fink, Frank; Geddes, Clive L.; Pfeifer, Lutz; Raabe, Ferdinand; Scheper, Thomas-Helmut; Ulrich, Elizabeth; Marx, Uwe

1999-04-01

The new medical developments, e.g. immune therapy, patient oriented chemotherapy or even gene therapy, create a questionable doubt to the further requirement of animal test. Instead the call for humanitarian reproductive in vitro models becomes increasingly louder. Pharmaceutical usage of in vitro has a long proven history. In cancer research and therapy, the effect of chemostatica in vitro in the so-called oncobiogram is being tested; but the assays do not always correlate with in vivo-like drug resistance and sensitivity. We developed a drug test system in vitro, feasible for therapeutic drug monitoring by the combination of tissue cultivation in hollow fiber bioreactors and fiber optic sensors for monitoring the pharmaceutical effect. Using two fiber optic sensors - an optical oxygen sensor and a metabolism detecting Laserfluoroscope, we were able to successfully monitor the biological status of tissue culture and the drug or toxic effects of in vitro pharmaceutical testing. Furthermore, we developed and patented a system for monitoring the effect of minor toxic compounds which can induce Sick Building Syndrome.

Adsorption Properties of Lignin-derived Activated Carbon Fibers (LACF)

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

Contescu, Cristian I.; Gallego, Nidia C.; Thibaud-Erkey, Catherine

The object of this CRADA project between Oak Ridge National Laboratory (ORNL) and United Technologies Research Center (UTRC) is the characterization of lignin-derived activated carbon fibers (LACF) and determination of their adsorption properties for volatile organic compounds (VOC). Carbon fibers from lignin raw materials were manufactured at Oak Ridge National Laboratory (ORNL) using the technology previously developed at ORNL. These fibers were physically activated at ORNL using various activation conditions, and their surface area and pore-size distribution were characterized by gas adsorption. Based on these properties, ORNL did down-select five differently activated LACF materials that were delivered to UTRC formore » measurement of VOC adsorption properties. UTRC used standard techniques based on breakthrough curves to measure and determine the adsorption properties of indoor air pollutants (IAP) - namely formaldehyde and carbon dioxide - and to verify the extent of saturated fiber regenerability by thermal treatments. The results are summarized as follows: (1) ORNL demonstrated that physical activation of lignin-derived carbon fibers can be tailored to obtain LACF with surface areas and pore size distributions matching the properties of activated carbon fibers obtained from more expensive, fossil-fuel precursors; (2) UTRC investigated the LACF potential for use in air cleaning applications currently pursued by UTRC, such as building ventilation, and demonstrated their regenerability for CO2 and formaldehyde, (3) Both partners agree that LACF have potential for possible use in air cleaning applications.« less

New fiber laser for lidar developments in disaster management

NASA Astrophysics Data System (ADS)

Besson, C.; Augere, B.; Canat, G.; Cezard, N.; Dolfi-Bouteyre, A.; Fleury, D.; Goular, D.; Lombard, L.; Planchat, C.; Renard, W.; Valla, M.

2014-10-01

Recent progress in fiber technology has enabled new laser designs along with all fiber lidar architectures. Their asset is to avoid free-space optics, sparing lengthy alignment procedures and yielding compact setups that are well adapted for field operations and on board applications thanks to their intrinsic vibration-resistant architectures. We present results in remote sensing for disaster management recently achieved with fiber laser systems. Field trials of a 3-paths lidar vibrometer for the remote study of modal parameters of buildings has shown that application-related constraints were fulfilled and that the obtained results are consistent with simultaneous in situ seismic sensors measurements. Remote multi-gas detection can be obtained using broadband infrared spectroscopy. Results obtained on methane concentration measurement using an infrared supercontinuum fiber laser and analysis in the 3-4 μm band are reported. For gas flux retrieval, air velocity measurement is also required. Long range scanning all-fiber wind lidars are now available thanks to innovative laser architectures. High peak power highly coherent pulses can be extracted from Er3+:Yb3+ and Tm3+ active fibers using methods described in the paper. The additional laser power provides increased coherent lidar capability in range and scanning of large areas but also better system resistance to adverse weather conditions. Wind sensing at ranges beyond 10 km have been achieved and on-going tests of a scanning system dedicated to airport safety is reported.

Bioinspired design and macroscopic assembly of poly(vinyl alcohol)-coated graphene into kilometers-long fibers.

PubMed

Kou, Liang; Gao, Chao

2013-05-21

Nacre is characterized by its excellent mechanical performance due to the well-recognized "brick and mortar" structure. Many efforts have been applied to make nacre-mimicking materials, but it is still a big challenge to realize their continuous production. Here, we prepared sandwich-like building blocks of poly(vinyl alcohol) (PVA)-coated graphene, and achieved high-nanofiller-content kilometers-long fibers by continuous wet-spinning assembly technology. The fibers have a strict "brick and mortar" layered structure, with graphene sheet as rigid brick and PVA as soft mortar. The mortar thickness can be precisely tuned from 2.01 to 3.31 nm by the weight feed ratio of PVA to graphene, as demonstrated by both atomic force microscopy and X-ray diffraction measurements. The mechanical strength of the nacre-mimicking fibers increases with increasing the content of PVA, and it rises gradually from 81 MPa for the fiber with 53.1 wt% PVA to 161 MPa for the fiber with 65.8 wt% PVA. The mechanical performance of our fibers was independent of the molecular weight (MW) of PVA in the wide range of 2-100 kDa, indicating that low MW polymers can also be used to make strong nanocomposites. The tensile stress of fibers immersed in PVA 5 wt% solution reached ca. 200 MPa, surpassing the values of nacre and most of other nacre-mimicking materials. The nacre-mimicking fibers are highly electrically conductive (∼350 S m(-1)) after immersing in hydroiodic acid, enabling them to connect a circuit to illuminate an LED lamp.

Comparison of self-written waveguide techniques and bulk index matching for low-loss polymer waveguide interconnects

NASA Astrophysics Data System (ADS)

Burrell, Derek; Middlebrook, Christopher

2016-03-01

Polymer waveguides (PWGs) are used within photonic interconnects as inexpensive and versatile substitutes for traditional optical fibers. The PWGs are typically aligned to silica-based optical fibers for coupling. An epoxide elastomer is then applied and cured at the interface for index matching and rigid attachment. Self-written waveguides (SWWs) are proposed as an alternative to further reduce connection insertion loss (IL) and alleviate marginal misalignment issues. Elastomer material is deposited after the initial alignment, and SWWs are formed by injecting ultraviolet (UV) light into the fiber or waveguide. The coupled UV light cures a channel between the two differing structures. A suitable cladding layer can be applied after development. Such factors as longitudinal gap distance, UV cure time, input power level, polymer material selection and choice of solvent affect the resulting SWWs. Experimental data are compared between purely index-matched samples and those with SWWs at the fiber-PWG interface. It is shown that < 1 dB IL per connection can be achieved by either method and results indicate lowest potential losses associated with a fine-tuned self-writing process. Successfully fabricated SWWs reduce overall processing time and enable an effectively continuous low-loss rigid interconnect.