Erbium-doped twin-core fibre narrow-band filter for fibre lasers

Czech Academy of Sciences Publication Activity Database

Peterka, Pavel; Kaňka, Jiří

2001-01-01

Roč. 33, 4/5 (2001), s. 571-581 ISSN 0306-8919. [Optical Waveguide Theory and Numerical Modelling /8./. Prague, 26.05.2000-27.05.2000] R&D Projects: GA ČR GA102/99/M057; GA ČR GA102/99/0393; GA AV ČR IAC2067902 Grant - others:EU COST(XE) OC 265.10 Institutional research plan: CEZ:AV0Z2067918 Keywords : optical fibre lasers * optical fibre filters * optical fibre couplers Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 0.706, year: 2001 http://www.ufe.cz/~peterka/opera/OQE_Peterka01_fulltext.pdf

A tuneable, power efficient and narrow single longitudinal mode fibre ring laser using an inline dual-taper fibre Mach–Zehnder filter

International Nuclear Information System (INIS)

Ahmad, H; Dernaika, M; Alimadad, M; Ibrahim, M F; Lim, K S; Harun, S W; Kharraz, O M

2014-01-01

A tuneable single longitudinal mode fibre ring laser with dual-taper fibre filter is proposed and experimentally demonstrated in this paper. The single longitudinal mode operation, and power limitations for a Mach–Zehnder interferometer filter generated from a single mode fibre, are verified for the first time. Incorporating an in-line taper fibre Mach–Zehnder interferometer filter inside the laser ring cavity causes a spatial mode beating interference, resulting in a passive narrow band filter with the ability to generate stable single longitudinal modes. The single longitudinal mode achieves a side mode suppression ratio of more than 60 dB using low pump power. The tuneability of the fibre laser ranges from 1525 to 1562 nm using a passive band pass filter. A study of the stability and limitation of the single longitudinal mode in the Mach–Zehnder tapered fibre is also presented. (paper)

Air gap membrane distillation. 2. Model validation and hollow fibre module performance analysis

NARCIS (Netherlands)

Guijt, C.M.; Meindersma, G.W.; Reith, T.; de Haan, A.B.

2005-01-01

In this paper the experimental results of counter current flow air gap membrane distillation experiments are presented and compared with predictive model calculations. Measurements were carried out with a cylindrical test module containing a single hollow fibre membrane in the centre and a

Light and gas confinement in hollow-core photonic crystal fibre based photonic microcells

DEFF Research Database (Denmark)

Benabid, F.; Roberts, John; Couny, F.

2009-01-01

guides via a photonic bandgap and the other guides by virtue of an inhibited coupling between core and cladding mode constituents. For the former fibre type, we explore how the bandgap is formed using a photonic analogue of the tight-binding model and how it is related to the anti-resonant reflection...... on electromagnetically induced transparency in a rubidium filled hollow-core photonic crystal fibre, the CW-pumped hydrogen Raman laser and the generation of multi-octave spanning stimulated Raman scattering spectral combs....

Hollow core waveguide as mid-infrared laser modal beam filter

Energy Technology Data Exchange (ETDEWEB)

Patimisco, P.; Giglio, M.; Spagnolo, V. [Dipartimento Interateneo di Fisica, Università e Politecnico di Bari, CNR-IFN UOS BARI, Via Amendola 173, 70126 Bari (Italy); Sampaolo, A. [Dipartimento Interateneo di Fisica, Università e Politecnico di Bari, CNR-IFN UOS BARI, Via Amendola 173, 70126 Bari (Italy); Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, Texas 77005 (United States); Kriesel, J. M. [Opto-Knowledge Systems, Inc. (OKSI), 19805 Hamilton Ave., Torrance, California 90502-1341 (United States); Tittel, F. K. [Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, Texas 77005 (United States)

2015-09-21

A novel method for mid-IR laser beam mode cleaning employing hollow core waveguide as a modal filter element is reported. The influence of the input laser beam quality on fiber optical losses and output beam profile using a hollow core waveguide with 200 μm-bore size was investigated. Our results demonstrate that even when using a laser with a poor spatial profile, there will exist a minimum fiber length that allows transmission of only the Gaussian-like fundamental waveguide mode from the fiber, filtering out all the higher order modes. This essentially single mode output is preserved also when the waveguide is bent to a radius of curvature of 7.5 cm, which demonstrates that laser mode filtering can be realized even if a curved light path is required.

Fibre Optic Notch Filter For The Antiproton Decelerator Stochastic Cooling System

CERN Document Server

Simmonds, Max Vincent John

2016-01-01

The project scope included reverse engineering, upgrading, and recovering the operational conditions of an existing fibre optic notch filter. Once operational, tests were to be preformed to confirm the performance of the temperature stabilisation. The end goal is to use said notch filter in the Antiproton Decelerator (AD) facility at CERN to help aid antimatter research. The notch filter was successfully reverse engineered and then documented. Changes were made in order to increase performance and reliability, and also allow easy integration into the AD. An additional phase was added whereby the notch filter was to be controller via a touchscreen computer, situated next to the filter, allowing engineers to set-up each of the electronic devices used. While one of the devices (Motorised Delay Line) can be controlled by the touchscreen computer, the other two cannot.Due to time constraints and difficulties with the Beckhoff TwincatII programming language, the USB devices were not able to be controlled via the To...

Three-dimensional porous hollow fibre copper electrodes for efficient and high-rate electrochemical carbon dioxide reduction

NARCIS (Netherlands)

Kas, Recep; Hummadi, Khalid Khazzal; Kortlever, Ruud; de Wit, Patrick; Milbrat, Alexander; Luiten-Olieman, Maria W.J.; Benes, Nieck Edwin; Koper, Marc T.M.; Mul, Guido

2016-01-01

Aqueous-phase electrochemical reduction of carbon dioxide requires an active, earth-abundant electrocatalyst, as well as highly efficient mass transport. Here we report the design of a porous hollow fibre copper electrode with a compact three-dimensional geometry, which provides a large area,

Surface modification of poly(vinylidene fluoride) hollow fibre membranes for biogas purification in a gas-liquid membrane contactor system.

Science.gov (United States)

Jin, Pengrui; Huang, Chuan; Li, Jiaxiang; Shen, Yadong; Wang, Liao

2017-11-01

The wetting of hollow fibre membranes decreases the performance of the liquid-gas membrane contactor for CO 2 capture in biogas upgrading. To solve this problem, in this work, a poly(vinylidene fluoride) (PVDF) hollow fibre membrane for a liquid-gas membrane contactor was coated with a superhydrophobic layer composed of a combination of hydrophobic SiO 2 nanoparticles and polydimethylsiloxane (PDMS) by the method of spray deposition. A rough layer of SiO 2 deposited on the PVDF membrane resulted in an enhanced surface hydrophobicity. The surface structure of the pristine PVDF significantly affected the homogeneity of the generated SiO 2 layer. A uniform surface coating on the PVDF upper layer resulted from the presence of micrometre and nanometre-sized roughness on the surface of the PVDF membrane, which was achieved with a SiO 2 concentration of 4.44 mg ml -1 (0.2 g/45 ml) in the coating solution. As a result, the water contact angle of the modified surface was recorded as 155 ± 3°, which is higher than that of the pristine surface. The high contact angle is advantageous for reducing the wetting of the membrane. Additional mass transfer resistance was introduced by the superhydrophobic layer. In addition, continuous CO 2 absorption tests were carried out in original and modified PVDF hollow fibre membrane contactors, using monoethanolamine (MEA) solution as the absorbent. A long-term stability test revealed that the modified PVDF hollow fibre membrane contactor was able to outperform the original membrane contactor and demonstrated outstanding long-term stability, suggesting that spray deposition is a promising approach to obtain superhydrophobic PVDF membranes for liquid-gas membrane absorption.

Supported graphene oxide hollow fibre membrane for oily wastewater treatment

Science.gov (United States)

Othman, Nur Hidayati; Alias, Nur Hashimah; Shahruddin, Munawar Zaman; Hussein, Siti Nurliyana Che Mohamed; Dollah, Aqilah

2017-12-01

Oil and gas industry deals with a large amount of undesirable discharges of liquid, solid, and gaseous wastes and the amounts can considerably change during the production phases. Oilfield wastewater or produced water is known to constitute various organic and inorganic components. Discharging the produced water can pollute surface and underground water and therefore the necessity to treat this oily wastewater is an inevitable challenge. The current technologies for the treatment of this metastable oil-in-water are not really effective and very pricey. As a result, there is a great interest from many parties around the world in finding cost-effective technologies. In recent years, membrane processes have been utilized for oily wastewater treatment. In these work, a graphene oxide membrane supported on a highly porous Al2O3 hollow fibre was prepared using vacuum assisted technique and its performance in treating oily wastewater was investigated. Graphene oxide (GO) was prepared using a modified Hummer's method and further characterized using XRD, FTIR, TGA and SEM. The results showed that the GO was successfully synthesized. The GO membrane was deposited on alumina hollow fibre substrates. The membrane performance was then investigated using dead-end filtration setup with synthetic oily wastewater as a feed. The effects of operating times on rejection rate and permeate flux were investigated. The experimental results showed that the oil rejections were over 90%. It was concluded that the supported GO membrane developed in this study may be considered feasible in treating oily wastewater. Detail study on the effects of transmembrane pressure, oil concentration, pH and fouling should be carried out in the future

Investigation on the effect of sintering temperature on kaolin hollow fibre membrane for dye filtration.

Science.gov (United States)

Mohtor, Nur Hamizah; Othman, Mohd Hafiz Dzarfan; Ismail, Ahmad Fauzi; Rahman, Mukhlis A; Jaafar, Juhana; Hashim, Nur Awanis

2017-07-01

Despite its extraordinary price, ceramic membrane can still be able to surpass polymeric membrane in the applications that require high temperature and pressure conditions, as well as harsh chemical environment. In order to alleviate the high cost of ceramic material that still becomes one of the major factors that contributes to the high production cost of ceramic membrane, various attempts have been made to use low cost ceramic materials as alternatives to well-known expensive ceramic materials such as alumina, silica, and zirconia in the fabrication of ceramic membrane. Thus, local Malaysian kaolin has been chosen as the ceramic material in this study for the preparation of kaolin hollow fibre membrane since it is inexpensive and naturally abundant in Malaysia. Due to the fact that the sintering process plays a prominent role in obtaining the desired morphology, properties, and performances of prepared ceramic membrane, the aim of this work was to study the effect of different sintering temperatures applied (ranging from 1200 to 1500 °C) in the preparation of kaolin hollow fibre membrane via dry/wet phase inversion-based spinning technique and sintering process. The morphology and properties of membrane were then characterised by SEM, AFM, FTIR, XRD, and three-point bending test, while the performances of membrane were investigated by conducting water permeation and Reactive Black 5 (RB5) dye rejection tests. From the experimental results obtained, the sintering temperature of 1400 °C could be selected as the optimum sintering temperature in preparing the kaolin hollow fibre membrane with the dense sponge-like structure of separation layer that resulted in the good mechanical strength of 70 MPa with the appreciable water permeation of 75 L/h m 2  bar and RB5 rejection of 68%.

A monolithic integrated photonic microwave filter

Science.gov (United States)

Fandiño, Javier S.; Muñoz, Pascual; Doménech, David; Capmany, José

2017-02-01

Meeting the increasing demand for capacity in wireless networks requires the harnessing of higher regions in the radiofrequency spectrum, reducing cell size, as well as more compact, agile and power-efficient base stations that are capable of smoothly interfacing the radio and fibre segments. Fully functional microwave photonic chips are promising candidates in attempts to meet these goals. In recent years, many integrated microwave photonic chips have been reported in different technologies. To the best of our knowledge, none has monolithically integrated all the main active and passive optoelectronic components. Here, we report the first demonstration of a tunable microwave photonics filter that is monolithically integrated into an indium phosphide chip. The reconfigurable radiofrequency photonic filter includes all the necessary elements (for example, lasers, modulators and photodetectors), and its response can be tuned by means of control electric currents. This is an important step in demonstrating the feasibility of integrated and programmable microwave photonic processors.

Laser breakdown with millijoule trains of picosecond pulses transmitted through a hollow-core photonic-crystal fibre

CERN Document Server

Konorov, S O; Kolevatova, O A; Beloglasov, V I; Skibina, N B; Shcherbakov, A V; Wintner, E; Zheltikov, A M

2003-01-01

Sequences of picosecond pulses with a total energy in the pulse train of about 1 mJ are transmitted through a hollow-core photonic-crystal fibre with a core diameter of approximately 14 mu m. The fluence of laser radiation coupled into the core of the fibre under these conditions exceeds the breakdown threshold of fused silica by nearly an order of magnitude. The laser beam coming out of the fibre is then focused to produce a breakdown on a solid surface. Parameters of laser radiation were chosen in such a way as to avoid effects related to the excitation of higher order waveguide modes and ionization of the gas filling the fibre in order to provide the possibility to focus the output beam into a spot with a minimum diameter, thus ensuring the maximum spatial resolution and the maximum power density in the focal spot.

Tunable polarisation-maintaining filter based on liquid crystal photonic bandgap fibre

DEFF Research Database (Denmark)

Scolari, Lara; Olausson, Christina Bjarnal Thulin; Weirich, Johannes

2008-01-01

A tunable and polarisation-maintaining all-in-fibre filter based on a liquid crystal photonic bandgap fibre is demonstrated. Its polarisation extinction ratio reaches 14 dB at 1550 nm wavelength. Its spectral tunability range spans over 250 nm in the temperature range 30–70°C. The measured...

PIXE analysis of atmospheric particulate matter in glas fibre filters

International Nuclear Information System (INIS)

Tabacniks, M.H.; Orsini, C.Q.; Maenhaut, W.

1993-01-01

A 3-step extraction procedure was developed to allow particle-induced X-ray emission (PIXE) analysis of particulate matter in normal glass fibre filter samples. The detection limits, expressed in ng/m 3 of air, for the filter extracts were 5 to 30 times lower than those achieved by PIXE analysis or ordinary Nuclepore polycarbonate filter samples. The concentration results were compared with those obtained from routine atomic absorption spectrometry measurements and with the PIXE data from Nuclepore stacked filter unit samples taken in parallel. (orig.)

Light propagation in gas-filled kagomé hollow core photonic crystal fibres

Science.gov (United States)

Rodrigues, Sílvia M. G.; Facão, Margarida; Ferreira, Mário F. S.

2018-04-01

We study the propagation of light in kagomé hollow core photonic crystal fibres (HC-PCFs) filled with three different noble gases, namely, helium, xenon and argon. Various properties, including the guided modes, the group-velocity dispersion, and the nonlinear parameter were determined. The zero dispersion wavelength and the nonlinear parameter vary with the gas pressure which may be used to tune the generation of new frequencies using the same pump laser and the same fibre. In the case of the kagomé HC-PCF filled with xenon, the zero dispersion wavelength shifts from 693 to 1973 nm when the pressure is increased from 1 to 150bar, while the effective Kerr nonlinearity becomes comparable to that of silica. We have simulated the propagation of femtosecond pulses launched at 790 nm in order to study the generation of supercontinuum and UV light in kagomé HC-PCFs filled with the noble gases.

Liquid-phase membrane extraction of targeted pesticides from manufacturing wastewaters in a hollow fibre contactor with feed-stream recycle.

Science.gov (United States)

Đorđević, Jelena; Vladisavljević, Goran T; Trtić-Petrović, Tatjana

2017-01-01

A two-phase membrane extraction in a hollow fibre contactor with feed-stream recycle was applied to remove selected pesticides (tebufenozide, linuron, imidacloprid, acetamiprid and dimethoate) from their mixed aqueous solutions. The contactor consisted of 50 polypropylene hollow fibres impregnated with 5% tri-n-octylphosphine oxide in di-n-hexyl ether. For low-polar pesticides with log P ≥ 2 (tebufenozide and linuron), the maximum removal efficiency increased linearly from 85% to 96% with increasing the feed flow rate. The maximum removal efficiencies of more polar pesticides were significantly higher under feed recirculation (86%) than in a continuous single-pass operation (30%). It was found from the Wilson's plot that the mass transfer resistance of the liquid membrane can be neglected for low-polar pesticides. The pesticide removals from commercial formulations were similar to those from pure pesticide solutions, indicating that built-in adjuvants did not affect the extraction process.

In-line formation of chemically cross-linked P84® co-polyimide hollow fibre membranes for H2/CO2 separation

KAUST Repository

Choi, Seung Hak; Jansen, Johannes C.; Tasselli, Franco; Barbieri, Giuseppe; Drioli, Enrico

2010-01-01

In this study, chemically cross-linked asymmetric P84® co-polyimide hollow fibre membranes with enhanced separation performance were fabricated, using a dry-wet spinning process with an innovative in-line cross-linking step. The chemical

Efficient 1.9-μm Raman generation in a hydrogen-filled hollow-core fibre

Energy Technology Data Exchange (ETDEWEB)

Gladyshev, A V; Kolyadin, A N; Kosolapov, A F; Yatsenko, Yu P; Pryamikov, A D; Biryukov, A S; Bufetov, I A; Dianov, E M [Fiber Optics Research Center, Russian Academy of Sciences, Moscow (Russian Federation)

2015-09-30

Efficient Raman generation in a molecular hydrogenfilled hollow-core fibre having a cladding in the form of a single ring of capillaries has been demonstrated for the first time. The pump source used was a Q-switched Nd:YAG laser with a pulse duration of 125 ns, and a single-pass (cavity-free) configuration was employed. The maximum average output power at 1.9 μm was 300 mW, and the differential quantum efficiency was 87%, a record level for such experiments. (lasers)

All-in-fibre Rayleigh-rejection filter for raman spectroscopy

DEFF Research Database (Denmark)

Brunetti, Anna Chiara; Scolari, L.; Lund-Hansen, T.

2012-01-01

An in-line Rayleigh-rejection filter for Raman spectroscopy is demonstrated. The device is based on a solid-core photonic crystal fibre infiltrated with a high-index liquid. At room temperature, the filter exhibits a full width at half maximum bandwidth of 143 nm and an insertion loss of 0.3 d......B. A shift of 32 nm of the central wavelength is demonstrated by increasing the temperature from 22 to 70°C. FEM simulations of the spectra at different temperatures showed good agreement with experimental results. The device was successfully employed to perform Raman spectroscopy of a sample of cyclohexane...

New generation of optical fibres

Energy Technology Data Exchange (ETDEWEB)

Dianov, E M; Semjonov, S L; Bufetov, I A [Fiber Optics Research Center, Russian Academy of Sciences, Moscow (Russian Federation)

2016-01-31

The growing need for information in contemporary society is the motivating force behind the development of fibre optics in general and optical fibre communications in particular. Intensive research effort has been concentrated on designing new types of optical fibres and extending their application field. This paper reviews results of research on new types of optical fibres: bismuthdoped active fibres, multicore fibres and hollow-core fibres, which can be used as key components of systems that ensure further increase in optical information transfer rate. (invited paper)

Analysis of hollow fibre membrane systems for multicomponent gas separation

KAUST Repository

Khalilpour, Rajab

2013-02-01

This paper analysed the performance of a membrane system over key design/operation parameters. A computation methodology is developed to solve the model of hollow fibre membrane systems for multicomponent gas feeds. The model represented by a nonlinear differential algebraic equation system is solved via a combination of backward differentiation and Gauss-Seidel methods. Natural gas sweetening problem is investigated as a case study. Model parametric analyses of variables, namely feed gas quality, pressure, area, selectivity and permeance, resulted in better understanding of operating and design optima. Particularly, high selectivities and/or permeabilities are shown not to be necessary targets for optimal operation. Rather, a medium selectivity (<60 in the given example) combined with medium permeance (∼300-500×10-10mol/sm2Pa in the given case study) is more advantageous. This model-based membrane systems engineering approach is proposed for the synthesis of efficient and cost-effective multi-stage membrane networks. © 2012 The Institution of Chemical Engineers.

First application of hollow fiber filter for PWR condensate polishing

International Nuclear Information System (INIS)

Tsuda, S.; Otoha, K.; Takiguchi, H.

2002-01-01

In Tsuruga Unit-2 (PWR 1160 MWe commenced commercial operation in 1987), current procedure for secondary system clean-up before start-up had prolonged outage time and had consumed a huge amount of de-ionized (DI) water. In addition, iron oxide in condensate had accelerated the degradation of condensate demineralizer (CD) resin. The corrosion product of iron could also influence the secondary side corrosion of steam generator (SG) tubing if it intruded into SG through CD. To solve these problems, Japan Atomic Power Company (JAPC) decided to introduce hollow fiber filter (HFF) type condensate filter into Tsuruga-2, as the first application to PWR in the world. Because of retro-fitted HFF in Tsuruga Unit-2, limitations for installation space and flow resistance in condensate system and cost reduction required new design for compact and low differential pressure system and for long life filter module. JAPC and ORGANO assessed methodologies to achieve these goals. An advanced HFF system, including a newly developed compact HFF module design, was installed at Tsuruga Unit-2 in 1997 based on the assessment. During the 5 years since the installation, the HFF system has provided excellent crud removal that enables to shorten the outage period and to reduce DI water consumption drastically. Stable differential pressure (dP) trend of the HFF system indicates an expected module life of more than 7 years, with backwash cleaning required only 2 or 3 times per year. In addition to providing the expected operating cost reduction and improved SG tube integrity, numerous additional benefits have resulted from the retrofit. (authors)

Optimising cell aggregate expansion in a perfused hollow fibre bioreactor via mathematical modelling.

KAUST Repository

Chapman, Lloyd A C

2014-08-26

The need for efficient and controlled expansion of cell populations is paramount in tissue engineering. Hollow fibre bioreactors (HFBs) have the potential to meet this need, but only with improved understanding of how operating conditions and cell seeding strategy affect cell proliferation in the bioreactor. This study is designed to assess the effects of two key operating parameters (the flow rate of culture medium into the fibre lumen and the fluid pressure imposed at the lumen outlet), together with the cell seeding distribution, on cell population growth in a single-fibre HFB. This is achieved using mathematical modelling and numerical methods to simulate the growth of cell aggregates along the outer surface of the fibre in response to the local oxygen concentration and fluid shear stress. The oxygen delivery to the cell aggregates and the fluid shear stress increase as the flow rate and pressure imposed at the lumen outlet are increased. Although the increased oxygen delivery promotes growth, the higher fluid shear stress can lead to cell death. For a given cell type and initial aggregate distribution, the operating parameters that give the most rapid overall growth can be identified from simulations. For example, when aggregates of rat cardiomyocytes that can tolerate shear stresses of up to 0:05 Pa are evenly distributed along the fibre, the inlet flow rate and outlet pressure that maximise the overall growth rate are predicted to be in the ranges 2.75 x 10(-5) m(2) s(-1) to 3 x 10(-5) m(2) s(-1) (equivalent to 2.07 ml min(-1) to 2.26 ml min(-1)) and 1.077 x 10(5) Pa to 1.083 x 10(5) Pa (or 15.6 psi to 15.7 psi) respectively. The combined effects of the seeding distribution and flow on the growth are also investigated and the optimal conditions for growth found to depend on the shear tolerance and oxygen demands of the cells.

Performance evaluation and modelling studies of gravel--coir fibre--sand multimedia stormwater filter.

Science.gov (United States)

Samuel, Manoj P; Senthilvel, S; Tamilmani, D; Mathew, A C

2012-09-01

A horizontal flow multimedia stormwater filter was developed and tested for hydraulic efficiency and pollutant removal efficiency. Gravel, coconut (Cocos nucifera) fibre and sand were selected as the media and filled in 1:1:1 proportion. A fabric screen made up of woven sisal hemp was used to separate the media. The adsorption behaviour of coir fibre was determined in a series of column and batch studies and the corresponding isotherms were developed. The hydraulic efficiency of the filter showed a diminishing trend as the sediment level in inflow increased. The filter exhibited 100% sediment removal at lower sediment concentrations in inflow water (>6 g L(-1)). The filter could remove NO3(-), SO4(2-) and total solids (TS) effectively. Removal percentages of Mg(2+) and Na(+) were also found to be good. Similar results were obtained from a field evaluation study. Studies were also conducted to determine the pattern of silt and sediment deposition inside the filter body. The effects of residence time and rate of flow on removal percentages of NO3(-) and TS were also investigated out. In addition, a multiple regression equation that mathematically represents the filtration process was developed. Based on estimated annual costs and returns, all financial viability criteria (internal rate of return, net present value and benefit-cost ratio) were found favourable and affordable to farmers for investment in the developed filtration system. The model MUSIC was calibrated and validated for field conditions with respect to the developed stormwater filter.

Bench scale model studies on sanitary landfill leachate treatment with M. oleifera seed extract and hollow fibre micro-filtration membrane

Directory of Open Access Journals (Sweden)

S. A. Muyibi

2002-10-01

Full Text Available A laboratory-based study using a Bench Scale model of four unit operations made up of coagulation (using Moringa oleifera seed extract as a coagulant, flocculation, sedimentation and micro-filtration, have been adopted to treat the leachate from Air Hitman Sanitary Landfill at Puchong in Malaysia. M. oleifera dosages of 150 and 175 mg/L had achieved 43.8% Cadmium removal, 21.2% Total Chromium removal, 66.8% Lead removal and 16% Iron removal. It also removed 55.4% of Total Suspended Solids, 10% of Total Dissolved Solids and 24.2% of Volatile Suspended Solids. Micro-filtration hollow fibre membrane decreased the turbidity, total suspended solids, total dissolved solids, volatile suspended solids, and organic matter in the leachate by 98.3%, 96.7%, 20.8%, 36.6% and 21.9% respectively. Overall heavy metals removal after micro-filtration using hollow fibre membrane was 94% for Cadmium, 29.8% for Total Chromium, 73.2% for Lead, and 18.3% for Iron. The results have shown that M. oleifera is a promising natural polymer for removing heavy metals from leachates and may be used as a pre-treatment to eliminate a portion of the toxic heavy metals, which limits the activity of micro organisms in the leachates.

Polyethersulfone-based ultrafiltration hollow fibre membrane for drinking water treatment systems

Science.gov (United States)

Chew, Chun Ming; Ng, K. M. David; Ooi, H. H. Richard

2017-12-01

Conventional media/sand filtration has been the mainstream water treatment process for most municipal water treatment plants in Malaysia. Filtrate qualities of conventional media/sand filtration are very much dependent on the coagulation-flocculation process prior to filtration and might be as high as 5 NTU. However, the demands for better quality of drinking water through public piped-water supply systems are growing. Polymeric ultrafiltration (UF) hollow fibre membrane made from modified polyethersulfone (PES) material is highly hydrophilic with high tensile strength and produces excellent quality filtrate of below 0.3 NTU in turbidity. This advanced membrane filtration material is also chemical resistance which allows a typical lifespan of 5 years. Comparisons between the conventional media/sand filtration and PES-based UF systems are carried out in this paper. UF has been considered as the emerging technology in municipal drinking water treatment plants due to its consistency in producing high quality filtrates even without the coagulation-flocculation process. The decreasing cost of PES-based membrane due to mass production and competitive pricing by manufacturers has made the UF technology affordable for industrial-scale water treatment plants.

Comparison of PIXE and XRF analysis of airborne particulate matter samples collected on Teflon and quartz fibre filters

Science.gov (United States)

Chiari, M.; Yubero, E.; Calzolai, G.; Lucarelli, F.; Crespo, J.; Galindo, N.; Nicolás, J. F.; Giannoni, M.; Nava, S.

2018-02-01

Within the framework of research projects focusing on the sampling and analysis of airborne particulate matter, Particle Induced X-ray Emission (PIXE) and Energy Dispersive X-ray Fluorescence (ED-XRF) techniques are routinely used in many laboratories throughout the world to determine the elemental concentration of the particulate matter samples. In this work an inter-laboratory comparison of the results obtained from analysing several samples (collected on both Teflon and quartz fibre filters) using both techniques is presented. The samples were analysed by PIXE (in Florence, at the 3 MV Tandetron accelerator of INFN-LABEC laboratory) and by XRF (in Elche, using the ARL Quant'X EDXRF spectrometer with specific conditions optimized for specific groups of elements). The results from the two sets of measurements are in good agreement for all the analysed samples, thus validating the use of the ARL Quant'X EDXRF spectrometer and the selected measurement protocol for the analysis of aerosol samples. Moreover, thanks to the comparison of PIXE and XRF results on Teflon and quartz fibre filters, possible self-absorption effects due to the penetration of the aerosol particles inside the quartz fibre-filters were quantified.

Effect of internal pressure and gas/liquid interface area on the CO mass transfer coefficient using hollow fibre membranes as a high mass transfer gas diffusing system for microbial syngas fermentation.

Science.gov (United States)

Yasin, Muhammad; Park, Shinyoung; Jeong, Yeseul; Lee, Eun Yeol; Lee, Jinwon; Chang, In Seop

2014-10-01

This study proposed a submerged hollow fibre membrane bioreactor (HFMBR) system capable of achieving high carbon monoxide (CO) mass transfer for applications in microbial synthesis gas conversion systems. Hydrophobic polyvinylidene fluoride (PVDF) membrane fibres were used to fabricate a membrane module, which was used for pressurising CO in water phase. Pressure through the hollow fibre lumen (P) and membrane surface area per unit working volume of the liquid (A(S)/V(L)) were used as controllable parameters to determine gas-liquid volumetric mass transfer coefficient (k(L)a) values. We found a k(L)a of 135.72 h(-1) when P was 93.76 kPa and AS/VL was fixed at 27.5m(-1). A higher k(L)a of 155.16 h(-1) was achieved by increasing AS/VL to 62.5m(-1) at a lower P of 37.23 kPa. Practicality of HFMBR to support microbial growth and organic product formation was assessed by CO/CO2 fermentation using Eubacterium limosum KIST612. Copyright © 2014 Elsevier Ltd. All rights reserved.

Spectral broadening of 25 fs laser pulses via self-phase modulation in a neon filled hollow core fibre

Energy Technology Data Exchange (ETDEWEB)

Weichert, Stefan

2017-05-15

The goal of this work was the realisation of a setup for spectral broadening and subsequent compression of 25 fs laser pulses provided by a commercial Ti:Sapphire based CPA laser system by means of the hollow core fibre chirped mirror compressor technique. For the spectral broadening a vessel containing the hollow waveguide filled with a noble gas serving as the nonlinear medium was set up and an alignment procedure was developed. Neon was chosen as the nonlinear medium for the self-phase modulation of the pulses. With this setup spectral broadening, sufficient for supporting sub 5 fs pulses, was observed. The spectra at different input energies and neon gas pressures were measured and the stability of these and their respective Fourier transform-limited pulses determined in order to find an operating point. For the compression of the self-phase modulated pulses a chirped mirror compressor was designed and set up, but not tested yet. The layout of a single-shot intensity autocorrelator capable of estimating the pulse duration of sub 10 fs pulses was given.

Spectral broadening of 25 fs laser pulses via self-phase modulation in a neon filled hollow core fibre

International Nuclear Information System (INIS)

Weichert, Stefan

2017-05-01

The goal of this work was the realisation of a setup for spectral broadening and subsequent compression of 25 fs laser pulses provided by a commercial Ti:Sapphire based CPA laser system by means of the hollow core fibre chirped mirror compressor technique. For the spectral broadening a vessel containing the hollow waveguide filled with a noble gas serving as the nonlinear medium was set up and an alignment procedure was developed. Neon was chosen as the nonlinear medium for the self-phase modulation of the pulses. With this setup spectral broadening, sufficient for supporting sub 5 fs pulses, was observed. The spectra at different input energies and neon gas pressures were measured and the stability of these and their respective Fourier transform-limited pulses determined in order to find an operating point. For the compression of the self-phase modulated pulses a chirped mirror compressor was designed and set up, but not tested yet. The layout of a single-shot intensity autocorrelator capable of estimating the pulse duration of sub 10 fs pulses was given.

Investigation on Guided-Mode Characteristics of Hollow-Core Photonic Crystal Fibre at Near-Infrared Wavelengths

International Nuclear Information System (INIS)

Jin-Hui, Yuan; Chong-Xiu, Yu; Xin-Zhu, Sang; Wen-Jing, Li; Gui-Yao, Zhou; Shu-Guang, Li; Lan-Tian, Hou

2009-01-01

Guided-mode characteristics of hollow-core photonic crystal fibre (HC-PCF) are experimentally and theoretically investigated. The transmission spectrum in the range from 755 to 845 nm is observed and the loss is measured to be 0.12 dB/m at 800 nm by cut-back method. Based on the full-vector beam propagation method and the full-vector plane-wave method, the characteristics of mode field over propagation distance 1 m are simulated, and the results show that the propagation efficiency can be above 80%. Compared with the fundamental guided mode well confined in air core within shorter propagation distance, the second-order guided mode leaks into the cladding region and gradually attenuates due to larger refractive index difference. The primary loss factors in HC-PCF and the corresponding solutions are elementarily discussed. (fundamental areas of phenomenology (including applications))

3D-printed PMMA Preform for Hollow-core POF Drawing

DEFF Research Database (Denmark)

Zubel, M. G.; Fasano, Andrea; Woyessa, Getinet

2016-01-01

In this paper we report the first, to our knowledge, 3D-printed hollow-core poly(methyl methacrylate) (PMMA) preform for polymer optical fibre drawing. It was printed of commercial PMMA by means of fused deposition modelling technique. The preform was drawn to cane, proving good enough quality...... of drawing process and the PMMA molecular weight to be appropriate for drawing. This ascertains that the manufacturing process provides preforms suitable for hollow-core fibre drawing. The paper focuses on maximisation of transparency of PMMA 3D printouts by optimising printing process parameters: nozzle...... temperature, printing speed and infill...

Hollow Core Photonic Crystal Fibre Comprising a Fibre Grating in the Cladding and its Applications

DEFF Research Database (Denmark)

2010-01-01

An optical fibre is provided having a fibre cladding around a longitudinally extending optical propagation core. The cladding has a reflection region of a varying refractive index in the longitudinal direction....

Fibre optic communication key devices

CERN Document Server

Grote, Norbert

2017-01-01

The book gives an in-depth description of key devices of current and next generation fibre optic communication networks. Devices treated include semiconductor lasers, optical amplifiers, modulators, wavelength filters and other passives, detectors, all-optical switches, but relevant properties of optical fibres and network aspects are included as well. The presentations include the physical principles underlying the various devices, technologies used for their realization, typical performance characteristics and limitations, but development trends towards more advanced components are also illustrated. This new edition of a successful book was expanded and updated extensively. The new edition covers among others lasers for optical communication, optical switches, hybrid integration, monolithic integration and silicon photonics. The main focus is on Indium phosphide-based structures but silicon photonics is included as well. The book covers relevant principles, state-of-the-art implementations, status of curren...

Fabricating process of hollow out-of-plane Ni microneedle arrays and properties of the integrated microfluidic device

Science.gov (United States)

Zhu, Jun; Cao, Ying; Wang, Hong; Li, Yigui; Chen, Xiang; Chen, Di

2013-07-01

Although microfluidic devices that integrate microfluidic chips with hollow out-of-plane microneedle arrays have many advantages in transdermal drug delivery applications, difficulties exist in their fabrication due to the special three-dimensional structures of hollow out-of-plane microneedles. A new, cost-effective process for the fabrication of a hollow out-of-plane Ni microneedle array is presented. The integration of PDMS microchips with the Ni hollow microneedle array and the properties of microfluidic devices are also presented. The integrated microfluidic devices provide a new approach for transdermal drug delivery.

Multimode laser emission from dye-doped hollow polymer optical fibre

Indian Academy of Sciences (India)

2014-02-09

Feb 9, 2014 ... Fibre lasers; optical microcavities; whispering gallery modes. ... A blueshift in the mode structure was observed with decrease in fibre diameter leading to wide range tunability of the laser emission. ... International School of Photonics, Cochin University of Science & Technology, Cochin 682 022, India ...

"The blood pressure and dermal sensitivity effects of Nylon hollow fiber releasing Glycerin Trinitrate in vivo "

Directory of Open Access Journals (Sweden)

"Ostad SN

2002-09-01

Full Text Available In order to improve patient's compliance in taking glycerine trinitrate (GTN nylon hollow fiber which has been successfully used for release of chlorhexidine diacetate and levonorgestrel was employed to make nylon hollow fiber releasing GTN. Hollow nylon fibres of external diameter 0.63 mm, 75 mm long with an internal capacity of 16 μl, were filled with GTN (190 mg/ml in 70% ethanol (v/v or vehicle alone and the ends were heat-sealed. The fibers were then immersed in 10 ml of 0.9% (w/v saline in a separating funnel. The GTN release pattern from fiber, the effect of the product on blood pressure and its potential dermal toxicity were assessed. The release of GTN from the fibres was approximately 2.7 μg/min when the fibres contained 16 mg of drug. The results showed that the amount of GTN within the single fibre was enough to reduce blood pressure significantly, while it did not show significant dermal toxicity. It is concluded that GTN fiber, if used as monofilament, is not an alternative method for GTN delivery.

Multimode laser emission from dye-doped hollow polymer optical fibre

Indian Academy of Sciences (India)

2014-02-09

Feb 9, 2014 ... Dye-doped polymer optical fibre preforms were fabricated by the controlled polymeriza- tion of Rh B-doped methyl methacrylate (MMA). Hole in the preform can be achieved by placing a teflon rod on the centre of the glass tube during the polymerization. Final fibre structure with required diameter was ...

High Extinction Ratio In-Fibre Polarisers by Exploiting Tilted Fibre Bragg Grating Structures for Single-Polarisation High-Power Fibre Lasers and Amplifiers

Science.gov (United States)

2009-11-01

maintaining (PM) fibre, utilising polarisation hole-burning ( PHB ) effect to reduce homogeneous linewidth of the EDFL. In our work, we demonstrate a stable...loss filter which will induce some loss to the cavity around its paired attenuation band region, thus imposing PHB effect to the gain medium. The...polarisation-hole-burning ( PHB ) effect to realise multi-wavelength switchable function in proposed fibre ring laser system. In the proposed fibre ring laser

Monolithic Integrated Ceramic Waveguide Filters

OpenAIRE

Hunter, IC; Sandhu, MY

2014-01-01

Design techniques for a new class of integrated monolithic high permittivity ceramic waveguide filters are presented. These filters enable a size reduction of 50% compared to air-filled TEM filters with the same unloaded Q-Factor. Designs for both chebyshev and asymmetric generalized chebyshev filter are presented, with experimental results for an 1800 MHz chebyshev filter showing excellent agreement with theory.

Long-period fibre grating writing with a slit-apertured femtosecond laser beam (λ = 1026 nm)

International Nuclear Information System (INIS)

Dostovalov, A V; Wolf, A A; Babin, S A

2015-01-01

We report on long-period grating (LPG) writing in a standard telecom fibre, SMF-28e+, via refractive index modification by femtosecond pulses. A method is proposed for grating writing with a slit-apertured beam, which enables one to produce LPGs with reduced background losses and a resonance peak markedly stronger than that in the case of grating writing with a Gaussian beam. The method can be used to fabricate LPGs for use as spectral filters of fibre lasers and sensing elements of sensor systems. (fibre and integrated-optical structures)

Reclamation of the wastewater from an industrial park using hollow-fibre and spiral-wound membranes: 50 m3 d(-1) pilot testing and cost evaluation.

Science.gov (United States)

Chu, C P; Jiaoa, S R; Hung, J M; Lu, C J; Chung, Y J

2009-08-01

The feasibility of reclaiming effluent from industrial park wastewater treatment plants through a membrane process was evaluated in three phases. In phase 1 we selected nine wastewater treatment plants (WWTPs), each with a design capacity exceeding 10,000 m3 d(-1), and analyzed the corresponding effluent composition. 'Potential recycling percentage', R, ranged from 50% to 80% for the industrial park WWTPs, indicating a high feasibility for the reuse of effluent. In phase 2, a 50 m3 d(-1) pilot plant was installed in one of the selected WWTPs and underwent testing for one year. The quality of the reclaimed water was suitable for general-purpose industrial use. In the two ultrafiltration (UF) modules tested, the hydrophilic polyethersulfone hollow-fibre module was more tolerant to variable properties, and had higher recycling percentages than those of backwashable hydrophobic polyvinylidene difluoride spiral-wound module. Using the spiral-wound UF module helped reduce the cost for producing 1 m3 of reclaimed water (US$0.80) compared with a hollow-fibre module (US$0.88). In phase 3, we evaluated the negative effects of refluxing the reverse osmosis retentate, containing high total dissolved solids and non-biodegradable organics, with the biological treatment unit of the upstream WWTP. Biological compactibility tests showed that the refluxed retentate ratio should be reduced to maintain the conductivity of mixed liquor in the aeration tank at less than 110% of the original value.

An Integrated DEMATEL-VIKOR Method-Based Approach for Cotton Fibre Selection and Evaluation

Science.gov (United States)

Chakraborty, Shankar; Chatterjee, Prasenjit; Prasad, Kanika

2018-01-01

Selection of the most appropriate cotton fibre type for yarn manufacturing is often treated as a multi-criteria decision-making (MCDM) problem as the optimal selection decision needs to be taken in presence of several conflicting fibre properties. In this paper, two popular MCDM methods in the form of decision making trial and evaluation laboratory (DEMATEL) and VIse Kriterijumska Optimizacija kompromisno Resenje (VIKOR) are integrated to aid the cotton fibre selection decision. DEMATEL method addresses the interrelationships between various physical properties of cotton fibres while segregating them into cause and effect groups, whereas, VIKOR method helps in ranking all the considered 17 cotton fibres from the best to the worst. The derived ranking of cotton fibre alternatives closely matches with that obtained by the past researchers. This model can assist the spinning industry personnel in the blending process while making accurate fibre selection decision when cotton fibre properties are numerous and interrelated.

Fibre-concrete container

International Nuclear Information System (INIS)

2000-01-01

In this leaflet the fibre-concrete container for radioactive wastes is described. The fibre container is made of fibre-concrete that contains cement, aggregate, sand, filter, flame-silica, super-plastificator, water and scattered metal fibres. The fibre-concrete container has a dice shape with outer dimension 1.7 x 1.7 x 1.7 m. It is mounted of a container body, a container cover and two caps. Total weight of container is 4,240 kg, maximum weight of loaded container do not must exceed 15,000 kg. The physical and mechanical properties of the fibre-concrete container are described in detail. The fibre-concrete container manufactured for storing of low and intermediate radioactive wastes. A fibre-concrete container utilization to store of radioactive wastes solves these problems: increase of stability of stored packages of radioactive waste; watertightness within 300 years at least; static stability of bearing space; better utilization of bearing spaces; insulation of radioactive waste in a case of seismic and geological event; increase of fire resistance; and transport of radioactive waste

Radiation-resistance assessment of IR fibres for ITER thermography diagnostic system

International Nuclear Information System (INIS)

Brichard, B.; Ierschot, S. van; Ooms, H.; Berghmans, F.; Reichle, R.; Pocheau, C.; Decreton, M.

2006-01-01

The actively cooled target plates in the divertor of ITER will be subjected to high thermal fluxes (∼ 10 MW/m 2 ). These target plates are compound structures of an armour material at the surface - either carbon fibre reinforced carbon (CFC) or tungsten - and a water cooled CuCrZr structure inside or below. The thermal limit of the interface between the two materials must not exceed 550 o C. Therefore, the temperature must be carefully monitored to prevent structural damages of the divertor plates. Non contact measurements of the temperature offer the advantage to avoid weakening of the cooling plate structure which is already quite complex to manufacture. Infrared thermography of the target surface is therefore considered as a possible solution. Recently a diagnostic concept for spectrally resolved ITER divertor thermography using optical fibres has been proposed by CEA-Cadarache. However, the divertor region will have to face high-radiation flux and the radiation-resistance of InfraRed (IR)-fibres must be evaluated. In collaboration with CEA-Cadarache, an irradiation program has been started at SCK-CEN (Mol, Belgium) with the aim to measure the radiation-induced absorption of different IR fibre candidates operating in the 1-5 μm range. We selected various commercially available IR technologies: ZrF 4 , Hollow-Waveguide, Sapphire and Chalcogenide. For wavelengths below 2 μm we also tested low-OH silica fibres. We carried out a gamma irradiation at a maximum dose-rate of 0.42 Gy/s up to a total dose of about 5000 Gy. We showed that the optical transmission of ZrF 4 fibres strongly decreased under gamma radiation, primarily for wavelengths below 2 μm. In this type of fibre typical optical losses can reach 50 % at 5000 Gy around 3 μm. Nevertheless, the optical transmission can be significantly recovered by performing a thermal annealing treatment at a temperature of 100 o C. We also irradiated a Silver-coated hollow waveguide fibre at the same dose-rate but up

In-line formation of chemically cross-linked P84® co-polyimide hollow fibre membranes for H2/CO2 separation

KAUST Repository

Choi, Seung Hak

2010-12-13

In this study, chemically cross-linked asymmetric P84® co-polyimide hollow fibre membranes with enhanced separation performance were fabricated, using a dry-wet spinning process with an innovative in-line cross-linking step. The chemical modification was conducted by controlled immersion of the coagulated fibre in an aqueous 1,5-diamino-2-methylpentane (DAMP) cross-linker solution before the take-up. The effect of the cross-linker concentration on the thermal, mechanical, chemical and gas transport properties of the membranes was investigated. FT-IR/ATR analysis was used to identify the chemical changes in the polymer, while DSC analysis confirmed the changes in the Tg and the specific heat of the polymer upon cross-linking. Chemical cross-linking with a 10 wt.% aqueous DAMP solution strongly enhanced the H2/CO2 ideal selectivity from 5.3 to 16.1, while the H2 permeance of the membranes decreased from 7.06 × 10−3 to 1.01 × 10−3 m3(STP) m−2 h−1 bar−1 for a feed pressure of 1 bar at 25 °C. The increase of selectivity with decreasing permeance is somewhat higher than the slope in the Robeson upper bound, evidencing the positive effect of the cross-linking on the separation performance of the fibres. Simultaneously, the cross-linking leads to improved mechanical resistance of the membranes, which could be further enhanced by an additional thermal treatment. The produced membranes are therefore more suitable for use under harsh conditions and have a better overall performance than the uncross-linked ones.

A multiple hollow fibre liquid-phase microextraction method for the determination of halogenated solvent residues in olive oil.

Science.gov (United States)

Manso, J; García-Barrera, T; Gómez-Ariza, J L; González, A G

2014-02-01

The present paper describes a method based on the extraction of analytes by multiple hollow fibre liquid-phase microextraction and detection by ion-trap mass spectrometry and electron capture detectors after gas chromatographic separation. The limits of detection are in the range of 0.13-0.67 μg kg(-1), five orders of magnitude lower than those reached with the European Commission Official method of analysis, with three orders of magnitude of linear range (from the quantification limits to 400 μg kg(-1) for all the analytes) and recoveries in fortified olive oils in the range of 78-104 %. The main advantages of the analytical method are the absence of sample carryover (due to the disposable nature of the membranes), high enrichment factors in the range of 79-488, high throughput and low cost. The repeatability of the analytical method ranged from 8 to 15 % for all the analytes, showing a good performance.

OPTICAL FIBRES AND FIBREOPTIC SENSORS: Fibreoptic distributed temperature sensor with spectral filtration by directional fibre couplers

Science.gov (United States)

Kuznetsov, A. G.; Babin, Sergei A.; Shelemba, Ivan S.

2009-11-01

We demonstrate a Raman-based all-fibre temperature sensor utilising a pulsed erbium fibre laser. The sensor is made of a standard single-mode telecom fibre, SMF-28, and includes a number of directional couplers as band-pass filters. The temperature profile along a 7-km fibreoptic line is measured with an accuracy of 2oC and a spatial resolution of 10 m. In data processing, we take into account the difference in attenuation between the spectral components of the backscatter signal.

safety of carbon fibre reinforced plastic hollow sections in compression

African Journals Online (AJOL)

ADMINUSER

2014-01-06

Jan 6, 2014 ... Steel hollow sections were also designed using the same method. This serves as a basis of ..... used for the numerical analysis and design of circular and rectangular model sections. The software was used to analyse failure ...

Morphology and performance of polyvinylidene fluoride/perfluoro sulphonic acid hollow fiber ultrafiltration blend membranes

International Nuclear Information System (INIS)

Yuan, Guo-Lin; Xu, Zhen-Liang; Wei, Yong-Ming; Yu, Li-Yun

2009-01-01

Polyvinylidene fluoride-perfluoro sulphonic acid hollow fibre ultrafiltration blend membranes were prepared by wet-spinning method. Polyvinylpyrrolidone and ethanol aqueous solutions were employed as additive and coagulants, respectively. The effect of Polyvinylpyrrolidone concentration in the dopes and ethanol concentration in the coagulants on morphology and performance of Polyvinylidene fluoride -perfluoro sulphonic acid hollow fibre ultrafiltration blend membranes were investigated. Blend membranes were characterized in terms of precipitation kinetics, morphology, thermal property and separation performance. The results showed that the increments of Polyvinylpyrrolidone concentration in the dopes and ethanol concentration in coagulants both resulted in higher pure water permeation flux and worse rejection (R) of bovine serum albumin (with the increment of Polyvinylpyrrolidone concentration from 0 to 5 wt% in the dopes, pure water permeation increased from 41.7 L.m -2 .h -1 to 134 L.m -2 .h -1 and R decreased from 99.8% to 84.4% as well as with the increase in ethanol concentration in coagulants from 0 to 40 wt%, pure water permeation increased from 33.5 L.m -2 .h- 1 to 123 L.m -2 .h -1 and R decreased from 97.7% to 88.7%). However, the proportion of sponge-like structure in the cross-section of membranes decreased with the increasing Polyvinylpyrrolidone concentration in the dopes and the proportion increased with the increased ethanol concentration in the coagulations. In addition, the location of the sponge-like structure in the cross-section of membranes was significantly influenced by ethanol concentrations in the coagulants and differential scanning calorimeter results revealed that the crystallinity (X c ) of the blend membrane was in accordance with the proportion of sponge-like structure. These behaviours were attributed to the different roles of Polyvinylpyrrolidone in the dopes and ethanol in the coagulants, respectively. Polyvinylidene fluoride

OPTICAL FIBRES AND FIBREOPTIC SENSORS: Polarisation reflectometry of anisotropic optical fibres

Science.gov (United States)

Konstantinov, Yurii A.; Kryukov, Igor'I.; Pervadchuk, Vladimir P.; Toroshin, Andrei Yu

2009-11-01

Anisotropic, polarisation-maintaining fibres have been studied using a reflectometer and integrated optic polariser. Linearly polarised pulses were launched into the fibre under test at different angles between their plane of polarisation and the main optical axis of the fibre. A special procedure for the correlation analysis of these reflectograms is developed to enhance the reliability of the information about the longitudinal optical uniformity ofanisotropic fibres.

Manufacturing a Micro-model with Integrated Fibre Optic Pressure Sensors

NARCIS (Netherlands)

Zarikos, I.; Hassanizadeh, S.M.; van Oosterhout, L.M.; van Oordt, Wim

The measurement of fluid pressure inside pores is a major challenge in experimental studies of two-phase flow in porous media. In this paper, we describe the manufacturing procedure of a micro-model with integrated fibre optic pressure sensors. They have a circular measurement window with a diameter

Filtering device for primary coolant circuits in BWR type reactors

International Nuclear Information System (INIS)

Tajima, Fumio; Yamamoto, Tetsuo.

1985-01-01

Purpose: To obtain a filtering device with a large filtering area and requiring less space. Constitution: A condensate inlet for introducing condensates to be filtered of primary coolant circuits, a filtrate exit, a backwash water exit and a bent tube are disposed to a container, and a plurality of hollow thread membrane modules are suspended in the container. The condensates are caused to flow through the condensate inlet, filtered through the hollow thread membrane and then discharged from the filtrate exit. When the filtering treatment is proceeded to some extent, since solid contents captured in the hollow thread membranes are accumulated, a differential pressure is produced between the condensate inlet and the filtrate exit. When the differential pressure reaches a predetermined value, the backwash is conducted to discharge the liquid cleaning wastes through the backwash exit. The bent tube disposed to the container body is used for water and air draining. The hollow thread membranes are formed with porous resin such as of polyethylene. (Kawakami, Y.)

Photonic Crystal Fibres for Dispersion and Sensor Applications

DEFF Research Database (Denmark)

Sørensen, Thorkild

2005-01-01

of the involved nonlinear processes. A hollow-core photonic crystal fibre (HC-PCF) is used as a sensor for gas. It is filled with two gasses, 12C2H2 acetylene, and H13CN hydrogen cyanide, and the transmission spectra are subject for a discussion. A model for infusion speed of fluids to a capillary presented...

Manufacturing and testing of wavefront filters for DARWIN

Science.gov (United States)

Flatscher, R.; Artjushenko, V.; Sakharova, T.; Pereira do Carmo, Joao

2017-11-01

Wavefront filtering is mandatory in the realisation of nulling interferometers with high star light suppression capability required to detect extrasolar planets, such as the one foreseen for the ESA Darwin mission. This paper presents the design, manufacturing, and test results of single mode fibres to be used as wavefront filters in mid-infrared range. Fibres made from chalcogenide glass and silver halide crystals were produced. The first class can serve as wavefront filters up to a wavelength of 11 microns, while silver halide fibres can be used over the full Darwin wavelength range from 6.5 to 18 micron. The chalcogenide glass fibres were drawn by double crucible method whereas polycrystalline fibres from silver halides were fabricated by multiple extrusion from a crystalline preform. Multi-layer AR-coatings for fibre ends were developed and environmentally tested for both types of fibres. Special fibre facet polishing procedures were established, in particular for the soft silver halide fibre ends. Cable design and assembly process were also developed, including termination by SMA-connectors with ceramic ferrules and fibre protection by loose PEEK-tubings to prevent excessive bending and chemical attacks for fibres. The wavefront filtering capability of the fibres was demonstrated on a high quality Mach-Zehnder interferometer. Two different groups of laser sources were used to measure the wavefront filtering of the fibres by using a CO-laser for testing in the lower sub-band and a CO2-laser to check the upper sub-band. Measurements of the fibres far field intensity distribution and transmission were performed for numerous cable samples. Single mode behaviour was observed in more than 25 silver halide fibre cables before AR-coating of their ends, while after that 17 cables were compliant with all technical requirements. Residual cladding modes existing in short single mode fibres were effectively removed by applying of a proper absorbing jacket to the fibre

Hollow fibre supported liquid membrane extraction of diphenylhydramine, chlorpheniramine and ketoprofen in pharmaceutical products

Directory of Open Access Journals (Sweden)

Titus A.M. Msagati

2010-08-01

Full Text Available A simple sample pre-treatment method utilizing hollow fibre supported liquid membrane (HFSLM was carried out on pharmaceuticals samples comprising of cough syrups (CS1 and CS2 and an anti-inflammatory product (AI. The active ingredients targeted in the extraction process were diphenylhydramine (DPH, chlorpheniramine (CPA [(S-γ-(4-chlorophenyl-N,N-dimethyl-2-pyridinepropanamine maleate salt] and ketoprofen (KP [(RS2-(3-benzoylphenyl-propionic acid] which were detected by a high performance liquid chromatograph (HPLC-UV/DAD after HFSLM process. Factors controlling the efficiency of HFSLM extraction such as sample pH, stripping phase pH, enrichment time, stirring speed as well as the organic solvent used for the entrapment of these analytes were optimized to achieve the best selectivity and high enrichment factors. KP extracted from AI product had optimal pH of 10 for the stripping solution and 4 for sample with enrichment factors of 339. DPH had optimal pH of 12 (sample and 3 for the stripping solution and had enrichment factors of 519. The optimal sample pH for CPA was 0.5 while the stripping phase pH was 13. The HFSLM technique showed 81% recovery of DPH from CS1, while for CPA from CS2 was 78 % and that of KP from AI was 80 %. The LODs obtained were 0.06 mu;g/L for all the compounds.

Liquid aerosol filtration by fibrous filters in interception and inertial regimes; Filtration des aerosols liquides par les filtres a fibres en regimes d`interception et d`inertie

Energy Technology Data Exchange (ETDEWEB)

Gougeon, R

1994-09-26

In most previous studies of aerosol filtration, attention is focused on the maximum penetrating particle size region where the predominant mechanisms for collection are brownian diffusion and interception. In contrary the inertial regime remains poorly understood. Therefore, the aim of this study was to improve understanding of the behaviour of fibrous filters with liquid aerosols ar high frontal velocities both in the stationary and nonstationary filtration. Stationary filtration is first investigated. Experiments are done with special filters called `formettes` which have well defined structural characteristics. Precise results obtained with those filters allow us to select two relations quoted in the literature in order to describe the diffusion and the interception and to determine an empirical correlation describing the inertial impaction. Then this correlation with an industrial filter. In the second part, the evolution of the performances of fibrous filters loaded with liquid aerosols is studied experimentally and theoretically. We show that, in the inertial regime the filter efficiency first decreases and then increases rapidly with the loading rate. This increase is particularly important at high frontal velocities and with big particles. Macroscopic observations of high loaded filters show that the liquid is located in the fibre`s intersections to form big flat surfaces. A tentative of describing the evolution of the filter efficiency in modifying our stationary filtration model in order to take into account those liquid surfaces in the filter gives encouraging results. (authors). 92 refs., 93 figs., 11 tabs., 4 appends.

A Cluster Randomized Controlled Trial to Reduce Childhood Diarrhea Using Hollow Fiber Water Filter and/or Hygiene–Sanitation Educational Interventions

Science.gov (United States)

Lindquist, Erik D.; George, C. M.; Perin, Jamie; Neiswender de Calani, Karen J.; Norman, W. Ray; Davis, Thomas P.; Perry, Henry

2014-01-01

Safe domestic potable water supplies are urgently needed to reduce childhood diarrheal disease. In periurban neighborhoods in Cochabamba, Bolivia, we conducted a cluster randomized controlled trial to evaluate the efficacy of a household-level hollow fiber filter and/or behavior change communication (BCC) on water, sanitation, and hygiene (WASH) to reduce the diarrheal disease in children less than 5 years of age. In total, 952 households were followed for a period of 12 weeks post-distribution of the study interventions. Households using Sawyer PointONE filters had significantly less diarrheal disease compared with the control arm during the intervention period, which was shown by diarrheal prevalence ratios of 0.21 (95% confidence interval [95% CI] = 0.15–0.30) for the filter arm and 0.27 (95% CI = 0.22–0.34) for the filter and WASH BCC arm. A non-significant reduction in diarrhea prevalence was reported in the WASH BCC study arm households (0.71, 95% CI = 0.59–0.86). PMID:24865680

Self-Q-switched ytterbium-doped cladding-pumped fibre laser

International Nuclear Information System (INIS)

Grukh, Dmitrii A; Kurkov, Andrei S; Razdobreev, I M; Fotiadi, A A

2002-01-01

A self-Q-switched ytterbium-doped double-clad fibre laser is described. A samarium-doped fibre is used as a filter for protecting a pump source. A fibre coupler is employed to obtain a nonlinear feedback. The mechanism of pulse formation in the laser is considered, and the dependence of its output pulse on the coupler parameters is studied. (solitons and optical fibers)

Detection of premature browning in ground beef with an integrated optical-fibre based sensor using reflection spectroscopy and fibre Bragg grating technology

International Nuclear Information System (INIS)

O'Farrell, M; Sheridan, C; Lewis, E

2007-01-01

This paper reports on an optical fibre based sensor system to detect the occurrence of premature browning in ground beef. Premature browning (PMB) occurs when, at a temperature below the pasteurisation temperature of 71 deg. C, there are no traces of pink meat left in the patty. PMB is more frequent if poorer quality beef or beef that has been stored under imperfect conditions. The experimental work pertaining to this paper involved cooking fresh meat and meat that has been stored in a freezer for, 1 week, 1 month and 3 months and recording the reflected spectra and temperature at the core of the product, during the cooking process, in order to develop a classifier based on the spectral response and using a Self-Organising Map (SOM) to classify the patties into one of four categories, based on their colour. Further tests were also carried out on developing an all-optical fibre sensor for measuring both the temperature and colour in a single integrated probe. The integrated probe contains two different sensor concepts, one to monitor temperature, based on Fibre Bragg Grating (FBG) technology and a second for meat quality, based on reflection spectroscopy in the visible wavelength range

Increasing dynamic range of a fibre Bragg grating edge-filtering interrogator with a proportional control loop

International Nuclear Information System (INIS)

Stan, Nikola; Bailey, D C; Chadderdon, S L; Selfridge, R H; Schultz, S M; Webb, S; Zikry, M; Peters, K J

2014-01-01

We present a fibre Bragg grating (FBG) interrogator that uses a microcontroller board and a tunable optical filter in a proportional control loop to increase dynamic range and achieve high strain sensitivity. It is an edge-filtering interrogator with added proportional control loop that locks the operating wavelength to the mid-reflection point on the FBG spectrum. The interrogator separates low-frequency (LF) components of strain and measures them with extended dynamic range, while at the same time measuring high-frequency (HF) strain without loss in strain sensitivity. In this paper, we describe the implementation of the interrogator and analyse the characteristics of individual components, such as the speed and voltage resolution of the microcontroller and the tunable optical filter. We measure the performance of the proportional control loop at frequencies up to 1 kHz and characterize the system using control theory. We illustrate the limitation of the conventional interrogator to measure strains greater than 40 μϵ and demonstrate successful application of the proposed interrogator for simultaneous measurement of 450 μϵ LF strain at 50 Hz superimposed with 32 kHz HF strain. (paper)

Adaptive Federal Kalman Filtering for SINS/GPS Integrated System

Institute of Scientific and Technical Information of China (English)

杨勇; 缪玲娟

2003-01-01

A new adaptive federal Kalman filter for a strapdown integrated navigation system/global positioning system (SINS/GPS) is given. The developed federal Kalman filter is based on the trace operation of parameters estimation's error covariance matrix and the spectral radius of update measurement noise variance-covariance matrix for the proper choice of the filter weight and hence the filter gain factors. Theoretical analysis and results from simulation in which the SINS/GPS was compared to conventional Kalman filter are presented. Results show that the algorithm of this adaptive federal Kalman filter is simpler than that of the conventional one. Furthermore, it outperforms the conventional Kalman filter when the system is undertaken measurement malfunctions because of its possession of adaptive ability. This filter can be used in the vehicle integrated navigation system.

Recovery of cesium from nuclear waste using hollow fibre supported liquid membrane containing calix[4]arene-bis-(2,3-naphtho)-crown-6

International Nuclear Information System (INIS)

Kandwal, P.; Mohapatra, P.K.; Ansari, S.A.; Manchanda, Vijay K.

2011-01-01

Transport behaviour of cesium through hollow fibre supported liquid membrane (HFSLM) containing calix[4]arenebis-(2,3-naphtho)-crown-6 (CNC) as carrier extractant, has been investigated under various experimental conditions. At tracer concentration of cesium, > 99% recovery of cesium was achieved from 3M HNO 3 solution to distilled water with 1 mM of CNC in 80% NPOE + 20 % n-dodecane mixture. Effect of feed phase acidity, ligand concentration, metal ion concentration etc. has been investigated. Recovery of cesium from Pressurized Heavy Water Reactor Simulated High Level Waste (PHWR-SHLW) using 1 mM CNC dissolved proposed diluent as the extractant, was carried out and it was found that it takes 12 hours of continuous operation for 88% recovery of metal ion. Nevertheless, the complete recovery of cesium from SHLW was possible after neutralization of strip phase acidity with NaOH. (author)

Reflective variable optical attenuators and fibre ring lasers for wavelength-division multiplexing systems

Science.gov (United States)

Liu, He Liang

Wavelength division multiplexing (WDM) optical fibre system is an important enabling technology to fulfill the demands for bandwidth in the modern information age. The main objective of this project is to study novel devices with the potential to enhance the performance of WDM systems. In particular, a novel reflective variable optical attenuator (RVOA) used for dynamic gain equalization (DGE) and fibre lasers based on an entirely new type of erbium-doped fibres with ultrawide tuning range were investigated theoretically and experimentally. We proposed a new type of RVOA device which could be potentially integrated with arrayed waveguide grating (AWG) to reduce the cost of DGE substantially. Initially, fibre-based RVOAs, fabricated with optical fibre components such as fibre coupler and Faraday rotator mirror, were investigated theoretically and experimentally. Larger attenuation range up to 22 dB was realized for fibre coupler-based ROVA with a Faraday rotator mirror and its polarization-dependent loss is about 0.5 dB. Then polymeric waveguide-based RVOAs were investigated theoretically and experimentally. Using an epoxy Novolak resin as core material and an UV-cured resin (Norland's NOA61) as cladding material, a polymeric waveguide RVOA was successfully fabricated. The dynamic 15 dB attenuation range was achieved and the PDL was less than 0.2 dB. The measured insertion loss of the polymeric waveguide RVOA was too large (about 18 dB) and was mainly induced by coupling loss, material loss and poor alignment. In the second part of the study, fibre ring lasers with continuous wavelength tuning over wide wavelength range and fibre ring lasers with discrete wavelength tuning were investigated. Tunable lasers are important devices in WDM systems because they could be employed as reserved sources and therefore avoiding the need to stock large inventory of lasers to cover the ITU-wavelength grid. In this project, erbium ions doped bismuth oxide glass fibres instead of

Advances in laser technology and fibre-optic delivery systems in lithotripsy.

Science.gov (United States)

Fried, Nathaniel M; Irby, Pierce B

2018-06-08

The flashlamp-pumped, solid-state holmium:yttrium-aluminium-garnet (YAG) laser has been the laser of choice for use in ureteroscopic lithotripsy for the past 20 years. However, although the holmium laser works well on all stone compositions and is cost-effective, this technology still has several fundamental limitations. Newer laser technologies, including the frequency-doubled, double-pulse YAG (FREDDY), erbium:YAG, femtosecond, and thulium fibre lasers, have all been explored as potential alternatives to the holmium:YAG laser for lithotripsy. Each of these laser technologies is associated with technical advantages and disadvantages, and the search continues for the next generation of laser lithotripsy systems that can provide rapid, safe, and efficient stone ablation. New fibre-optic approaches for safer and more efficient delivery of the laser energy inside the urinary tract include the use of smaller-core fibres and fibres that are tapered, spherical, detachable or hollow steel, or have muzzle brake distal fibre-optic tips. These specialty fibres might provide advantages, including improved flexibility for maximal ureteroscope deflection, reduced cross section for increased saline irrigation rates through the working channel of the ureteroscope, reduced stone retropulsion for improved stone ablation efficiency, and reduced fibre degradation and burnback for longer fibre life.

Modelling effects of current distributions on performance of micro-tubular hollow fibre solid oxide fuel cells

International Nuclear Information System (INIS)

Doraswami, U.; Droushiotis, N.; Kelsall, G.H.

2010-01-01

A three-dimensional model, considering mass, momentum, energy and charge conservation, was developed and the equations solved to describe the physico-chemical phenomena occurring within a single, micro-tubular hollow fibre solid oxide fuel cell (HF-SOFC). The model was used to investigate the spatial distributions of potential, current and reactants in a 10 mm long HF-SOFC. The predicted effects of location of current collectors, electrode conductivities, cathode thickness and porosity were analysed to minimise the ranges of current density distributions and maximise performance by judicious design. To decrease the computational load, azimuthal symmetry was assumed to model 50 and 100 mm long reactors in 2-D. With connectors at the same end of the HF-SOFC operating at a cell voltage of 0.5 V and a mean 5 kA m -2 , axial potential drops of ca. 0.14 V in the cathode were predicted, comparable to the cathode activation overpotential. Those potential drops caused average current densities to decrease from ca. 6.5 to ca.1 kA m -2 as HF-SOFC length increased from 10 to 100 mm, at which much of the length was inactive. Peak power densities were predicted to vary from 3.8 to -2 , depending on the location of the current collectors; performance increased with increasing cathode thickness and decreasing porosity.

Spectrofluorimetry with attomole sensitivity in photonic crystal fibres

International Nuclear Information System (INIS)

Williams, Gareth O S; Jones, Anita C; Euser, Tijmen G; Russell, Philip St J

2013-01-01

We report the use of photonic crystal fibres (PCF) as spectrofluorimetric systems in which sample solutions are excited within the microstructure of the fibre. The use of intra-fibre excitation has several advantages that combine to enable highly sensitive measurements of fluorescence spectra and lifetimes: long path-lengths are achieved by the efficient guidance of the fundamental mode; sample volumes contained within the micron-scale structure are very small, only a few nanolitres per cm of path; collection and guidance of the emitted fluorescence is efficient and the fluorescence lifetime is unperturbed. Fluorophores in bulk solution can be studied in hollow core PCF, whereas the use of PCF with a suspended, solid core enables selective excitation of molecules in close proximity to the silica surface, through interaction with the evanescent field. We demonstrate the measurement of fluorescence spectra and fluorescence lifetimes in each of these excitation regimes and report the detection of attomole quantities of fluorescein. (paper)

Dynamic population gratings in rare-earth-doped optical fibres

Energy Technology Data Exchange (ETDEWEB)

Stepanov, Serguei [Optics Department, CICESE, km.107 carr. Tijuana-Ensenada, Ensenada, 22860, BC (Mexico)], E-mail: steps@cicese.mx

2008-11-21

Dynamic Bragg gratings can be recorded in rare-earth (e.g. Er, Yb) doped optical fibres by two counter-propagating mutually coherent laser waves via local saturation of the fibre optical absorption or gain (in optically pumped fibres). Typical recording cw light power needed for efficient grating formation is of sub-mW-mW scale which results in characteristic recording/erasure times of 10-0.1 ms. This review paper discusses fundamental aspects of the population grating formation, their basic properties, relating wave-mixing processes and also considers different applications of these dynamic gratings in single-frequency fibre lasers, tunable filters, optical fibre sensors and adaptive interferometry.

Dynamic population gratings in rare-earth-doped optical fibres

International Nuclear Information System (INIS)

Stepanov, Serguei

2008-01-01

Dynamic Bragg gratings can be recorded in rare-earth (e.g. Er, Yb) doped optical fibres by two counter-propagating mutually coherent laser waves via local saturation of the fibre optical absorption or gain (in optically pumped fibres). Typical recording cw light power needed for efficient grating formation is of sub-mW-mW scale which results in characteristic recording/erasure times of 10-0.1 ms. This review paper discusses fundamental aspects of the population grating formation, their basic properties, relating wave-mixing processes and also considers different applications of these dynamic gratings in single-frequency fibre lasers, tunable filters, optical fibre sensors and adaptive interferometry.

Fully integrated low-loss band-pass filters for wireless applications

International Nuclear Information System (INIS)

Rais-Zadeh, M; Kapoor, A; Lavasani, H M; Ayazi, F

2009-01-01

Fully integrated low insertion loss micromachined band-pass filters are designed and fabricated on the silicon substrate (ρ = 10–20 Ω cm, ε r = 11.9) for UHF applications. Filters are made of silver, which has the highest conductivity of all metals, to minimize the ohmic loss. A detailed analysis for realizing low insertion loss and high out-of-band rejection filters using elliptic magnitude characteristics is presented, and a comprehensive model to take into account inductive parasitics of the interconnects is developed. Temperature characteristics of the filters are measured and show stable performance. The presented filters are different from the previously reported lumped element filters in that all filters are fully integrated on silicon substrate and occupy a remarkably smaller die area. Two filters are fabricated using the silver micromachining technique with center frequencies at 1.05 and 1.35 GHz. The filters have a constant 3 dB bandwidth of 300 MHz (28.6% and 22.2%) and an insertion loss of 1.4–1.7 dB. The low insertion loss and CMOS compatibility make the presented filters suitable candidates for radio frequency integrated circuits

Static and dynamic pile testing of reinforced concrete piles with structure integrated fibre optic strain sensors

Science.gov (United States)

Schilder, Constanze; Kohlhoff, Harald; Hofmann, Detlef; Basedau, Frank; Habel, Wolfgang R.; Baeßler, Matthias; Niederleithinger, Ernst; Georgi, Steven; Herten, Markus

2013-05-01

Static and dynamic pile tests are carried out to determine the load bearing capacity and the quality of reinforced concrete piles. As part of a round robin test to evaluate dynamic load tests, structure integrated fibre optic strain sensors were used to receive more detailed information about the strains along the pile length compared to conventional measurements at the pile head. This paper shows the instrumentation of the pile with extrinsic Fabry-Perot interferometers sensors and fibre Bragg gratings sensors together with the results of the conducted static load test as well as the dynamic load tests and pile integrity tests.

A discrete fibre dispersion method for excluding fibres under compression in the modelling of fibrous tissues.

Science.gov (United States)

Li, Kewei; Ogden, Ray W; Holzapfel, Gerhard A

2018-01-01

Recently, micro-sphere-based methods derived from the angular integration approach have been used for excluding fibres under compression in the modelling of soft biological tissues. However, recent studies have revealed that many of the widely used numerical integration schemes over the unit sphere are inaccurate for large deformation problems even without excluding fibres under compression. Thus, in this study, we propose a discrete fibre dispersion model based on a systematic method for discretizing a unit hemisphere into a finite number of elementary areas, such as spherical triangles. Over each elementary area, we define a representative fibre direction and a discrete fibre density. Then, the strain energy of all the fibres distributed over each elementary area is approximated based on the deformation of the representative fibre direction weighted by the corresponding discrete fibre density. A summation of fibre contributions over all elementary areas then yields the resultant fibre strain energy. This treatment allows us to exclude fibres under compression in a discrete manner by evaluating the tension-compression status of the representative fibre directions only. We have implemented this model in a finite-element programme and illustrate it with three representative examples, including simple tension and simple shear of a unit cube, and non-homogeneous uniaxial extension of a rectangular strip. The results of all three examples are consistent and accurate compared with the previously developed continuous fibre dispersion model, and that is achieved with a substantial reduction of computational cost. © 2018 The Author(s).

High Efficiency Particulate Air (HEPA) filters from polyester and polypropylene fibre nonwovens

CSIR Research Space (South Africa)

Boguslavsky, L

2010-10-01

Full Text Available filtration efficiency. Glass fibres are more harmful to human, compared to polypropylene and polyester fibre which are chemically inert. Hydroentanglement and chemical bonding techniques were utilised in manufacturing nonwovens for dry filtration. Acrylic...

Integrated cladding-pumped multicore few-mode erbium-doped fibre amplifier for space-division-multiplexed communications

Science.gov (United States)

Chen, H.; Jin, C.; Huang, B.; Fontaine, N. K.; Ryf, R.; Shang, K.; Grégoire, N.; Morency, S.; Essiambre, R.-J.; Li, G.; Messaddeq, Y.; Larochelle, S.

2016-08-01

Space-division multiplexing (SDM), whereby multiple spatial channels in multimode and multicore optical fibres are used to increase the total transmission capacity per fibre, is being investigated to avert a data capacity crunch and reduce the cost per transmitted bit. With the number of channels employed in SDM transmission experiments continuing to rise, there is a requirement for integrated SDM components that are scalable. Here, we demonstrate a cladding-pumped SDM erbium-doped fibre amplifier (EDFA) that consists of six uncoupled multimode erbium-doped cores. Each core supports three spatial modes, which enables the EDFA to amplify a total of 18 spatial channels (six cores × three modes) simultaneously with a single pump diode and a complexity similar to a single-mode EDFA. The amplifier delivers >20 dBm total output power per core and <7 dB noise figure over the C-band. This cladding-pumped EDFA enables combined space-division and wavelength-division multiplexed transmission over multiple multimode fibre spans.

Simple fibre based dispersion management for two-photon excited fluorescence imaging through an endoscope

DEFF Research Database (Denmark)

Dimopoulos, Konstantinos; Marti, Dominik; Andersen, Peter E.

2018-01-01

We want to implement two-photon excitation fluorescence microscopy (TPEFM) into endoscopes, since TPEFM can provide relevant biomarkers for cancer staging and grading in hollow organs, endoscopically accessible through natural orifices. However, many obstacles must be overcome, among others...... the delivery of short laser pulses to the distal end of the endoscope. To this avail, we present imaging results using an all-fibre dispersion management scheme in a TPEFM setup. The scheme has been conceived by Jespersen et al. in 20101 and relies on the combination of a single mode fibre with normal...

Distributed gas sensing with optical fibre photothermal interferometry.

Science.gov (United States)

Lin, Yuechuan; Liu, Fei; He, Xiangge; Jin, Wei; Zhang, Min; Yang, Fan; Ho, Hoi Lut; Tan, Yanzhen; Gu, Lijuan

2017-12-11

We report the first distributed optical fibre trace-gas detection system based on photothermal interferometry (PTI) in a hollow-core photonic bandgap fibre (HC-PBF). Absorption of a modulated pump propagating in the gas-filled HC-PBF generates distributed phase modulation along the fibre, which is detected by a dual-pulse heterodyne phase-sensitive optical time-domain reflectometry (OTDR) system. Quasi-distributed sensing experiment with two 28-meter-long HC-PBF sensing sections connected by single-mode transmission fibres demonstrated a limit of detection (LOD) of ∼10 ppb acetylene with a pump power level of 55 mW and an effective noise bandwidth (ENBW) of 0.01 Hz, corresponding to a normalized detection limit of 5.5ppb⋅W/Hz. Distributed sensing experiment over a 200-meter-long sensing cable made of serially connected HC-PBFs demonstrated a LOD of ∼ 5 ppm with 62.5 mW peak pump power and 11.8 Hz ENBW, or a normalized detection limit of 312ppb⋅W/Hz. The spatial resolution of the current distributed detection system is limited to ∼ 30 m, but it is possible to reduce down to 1 meter or smaller by optimizing the phase detection system.

High-flux MFI-alumina hollow fibres: a membrane-based process for on-board CO2 capture from internal combustion vehicles

International Nuclear Information System (INIS)

Nicolas, C.H.

2011-01-01

This work focuses on the conception and development of a membrane-based process for an on-board CO 2 capture/storage application. In a first part, we simulate an on-board CO 2 capture unit based on a membrane process for the case study of a heavy vehicle (≥3500 kg). This study includes an energy analysis of the impact of gas separation and compression on the required membrane surface and module volume, as well the autonomy of the storage unit and the energy overconsumption involved in the process. In a second part, we study the influence of the hollow-fibre support quality on the final intergrowth level of nano-composite MFI-alumina membranes. Special attention is devoted to the influence of the isomorphic substitution of silica by boron and germanium, and replacement of the counter-cation (proton) by other elements, on the CO 2 /N 2 separation and permeance properties. Next, a complete chapter has been devoted to the evaluation of the thermodynamic (adsorption) and kinetic (diffusion) parameters in the CO 2 /N 2 separation. Finally, we analyze the influence of standard pollutants (water, NO x , hydrocarbons) on the CO 2 separation properties of the synthesized membranes. (author)

Nonlinear Filtering with IMM Algorithm for Ultra-Tight GPS/INS Integration

Directory of Open Access Journals (Sweden)

Dah-Jing Jwo

2013-05-01

Full Text Available Abstract This paper conducts a performance evaluation for the ultra-tight integration of a Global positioning system (GPS and an inertial navigation system (INS, using nonlinear filtering approaches with an interacting multiple model (IMM algorithm. An ultra-tight GPS/INS architecture involves the integration of in-phase and quadrature components from the correlator of a GPS receiver with INS data. An unscented Kalman filter (UKF, which employs a set of sigma points by deterministic sampling, avoids the error caused by linearization as in an extended Kalman filter (EKF. Based on the filter structural adaptation for describing various dynamic behaviours, the IMM nonlinear filtering provides an alternative for designing the adaptive filter in the ultra-tight GPS/INS integration. The use of IMM enables tuning of an appropriate value for the process of noise covariance so as to maintain good estimation accuracy and tracking capability. Two examples are provided to illustrate the effectiveness of the design and demonstrate the effective improvement in navigation estimation accuracy. A performance comparison among various filtering methods for ultra-tight integration of GPS and INS is also presented. The IMM based nonlinear filtering approach demonstrates the effectiveness of the algorithm for improved positioning performance.

Integrated fiber Michelson interferometer based on poled hollow twin-core fiber.

Science.gov (United States)

Liu, Zhihai; Bo, Fusen; Wang, Lei; Tian, Fengjun; Yuan, Libo

2011-07-01

We propose an integrated fiber Michelson interferometer based on a poled hollow twin-core fiber. The Michelson interferometer can be used as an electro-optic modulator by thermal poling one core of the twin-core fiber and introducing second-order nonlinearity in the fiber. The proposed fiber Michelson interferometer is experimentally demonstrated under driving voltages at the frequency range of 149 to 1000 Hz. The half-wave voltage of the poled fiber is 135 V, and the effective second-order nonlinear coefficient χ² is 1.23 pm/V.

Fuzzy Adaptive Cubature Kalman Filter for Integrated Navigation Systems.

Science.gov (United States)

Tseng, Chien-Hao; Lin, Sheng-Fuu; Jwo, Dah-Jing

2016-07-26

This paper presents a sensor fusion method based on the combination of cubature Kalman filter (CKF) and fuzzy logic adaptive system (FLAS) for the integrated navigation systems, such as the GPS/INS (Global Positioning System/inertial navigation system) integration. The third-degree spherical-radial cubature rule applied in the CKF has been employed to avoid the numerically instability in the system model. In processing navigation integration, the performance of nonlinear filter based estimation of the position and velocity states may severely degrade caused by modeling errors due to dynamics uncertainties of the vehicle. In order to resolve the shortcoming for selecting the process noise covariance through personal experience or numerical simulation, a scheme called the fuzzy adaptive cubature Kalman filter (FACKF) is presented by introducing the FLAS to adjust the weighting factor of the process noise covariance matrix. The FLAS is incorporated into the CKF framework as a mechanism for timely implementing the tuning of process noise covariance matrix based on the information of degree of divergence (DOD) parameter. The proposed FACKF algorithm shows promising accuracy improvement as compared to the extended Kalman filter (EKF), unscented Kalman filter (UKF), and CKF approaches.

Fuzzy Adaptive Cubature Kalman Filter for Integrated Navigation Systems

Directory of Open Access Journals (Sweden)

Chien-Hao Tseng

2016-07-01

Full Text Available This paper presents a sensor fusion method based on the combination of cubature Kalman filter (CKF and fuzzy logic adaptive system (FLAS for the integrated navigation systems, such as the GPS/INS (Global Positioning System/inertial navigation system integration. The third-degree spherical-radial cubature rule applied in the CKF has been employed to avoid the numerically instability in the system model. In processing navigation integration, the performance of nonlinear filter based estimation of the position and velocity states may severely degrade caused by modeling errors due to dynamics uncertainties of the vehicle. In order to resolve the shortcoming for selecting the process noise covariance through personal experience or numerical simulation, a scheme called the fuzzy adaptive cubature Kalman filter (FACKF is presented by introducing the FLAS to adjust the weighting factor of the process noise covariance matrix. The FLAS is incorporated into the CKF framework as a mechanism for timely implementing the tuning of process noise covariance matrix based on the information of degree of divergence (DOD parameter. The proposed FACKF algorithm shows promising accuracy improvement as compared to the extended Kalman filter (EKF, unscented Kalman filter (UKF, and CKF approaches.

A biological oil adsorption filter

International Nuclear Information System (INIS)

Pasila, A.

2005-01-01

A new oil adsorption method called adsorption filtration (AF) has been developed. It is a technology where by oil residues can be cleaned from water by running it through a simple filter made from freeze treated, dried, milled and then fragmented plant material. By choosing suitable plants and fragmentation sizes it is possible to produce filters, which pass water but adsorb oil. The aim of this study was to investigate the possibilities of manufacturing oil adsorbing filter materials from reed canary grass (Phalaris arundinacea), flax (Linum usitatissimum L.) or hemp fibre (Cannabis sativa L.). The oil (80 ml) was mixed with de-ionised water (200 ml) and this mixture was filtered through 10 or 20 g adsorption filters. Fine spring harvested hemp fibre (diameter less than 1 mm) and reed canary grass fragments adsorb 2-4 g of oil per gram of adsorption material compared to 1-3 g of water. Adsorption filtration is thus a novel way of gathering spilled oil in shallow coastal waters before the oil reaches the shore. (author)

A biological oil adsorption filter

Energy Technology Data Exchange (ETDEWEB)

Pasila, A [University of Helsinki (Finland). Dept. of Agricultural Engineering and Household Technology

2005-12-01

A new oil adsorption method called adsorption filtration (AF) has been developed. It is a technology where by oil residues can be cleaned from water by running it through a simple filter made from freeze treated, dried, milled and then fragmented plant material. By choosing suitable plants and fragmentation sizes it is possible to produce filters, which pass water but adsorb oil. The aim of this study was to investigate the possibilities of manufacturing oil adsorbing filter materials from reed canary grass (Phalaris arundinacea), flax (Linum usitatissimum L.) or hemp fibre (Cannabis sativa L.). The oil (80 ml) was mixed with de-ionised water (200 ml) and this mixture was filtered through 10 or 20 g adsorption filters. Fine spring harvested hemp fibre (diameter less than 1 mm) and reed canary grass fragments adsorb 2-4 g of oil per gram of adsorption material compared to 1-3 g of water. Adsorption filtration is thus a novel way of gathering spilled oil in shallow coastal waters before the oil reaches the shore. (author)

Design of fibre reinforced PV concepts for building integrated applications

NARCIS (Netherlands)

Reinders, Angelina H.M.E.; de Wit, H.; de Boer, Andries; Ossenbrink Sinke, W.; Helm, P.

2009-01-01

Fibre reinforced polymers present an interesting encapsulation medium for PV-modules. Glass fibres can provide increased strength and stiffness to thin polymer layers overcoming the brittleness and limited deformability of glass-panes. Glass fibre reinforced polymers allows for transparency over a

Stochastic Integration H∞ Filter for Rapid Transfer Alignment of INS.

Science.gov (United States)

Zhou, Dapeng; Guo, Lei

2017-11-18

The performance of an inertial navigation system (INS) operated on a moving base greatly depends on the accuracy of rapid transfer alignment (RTA). However, in practice, the coexistence of large initial attitude errors and uncertain observation noise statistics poses a great challenge for the estimation accuracy of misalignment angles. This study aims to develop a novel robust nonlinear filter, namely the stochastic integration H ∞ filter (SIH ∞ F) for improving both the accuracy and robustness of RTA. In this new nonlinear H ∞ filter, the stochastic spherical-radial integration rule is incorporated with the framework of the derivative-free H ∞ filter for the first time, and the resulting SIH ∞ F simultaneously attenuates the negative effect in estimations caused by significant nonlinearity and large uncertainty. Comparisons between the SIH ∞ F and previously well-known methodologies are carried out by means of numerical simulation and a van test. The results demonstrate that the newly-proposed method outperforms the cubature H ∞ filter. Moreover, the SIH ∞ F inherits the benefit of the traditional stochastic integration filter, but with more robustness in the presence of uncertainty.

Fibre Optic Communication Key Devices

CERN Document Server

Grote, Norbert

2012-01-01

The book gives an in-depth description of the key devices of current and next generation fibre optic communication networks. In particular, the book covers devices such as semiconductor lasers, optical amplifiers, modulators, wavelength filters, and detectors but the relevant properties of optical fibres as well. The presentations include the physical principles underlying the various devices, the technologies used for the realization of the different devices, typical performance characteristics and limitations, and development trends towards more advanced components are also illustrated. Thus the scope of the book spans relevant principles, state-of-the-art implementations, the status of current research and expected future components.

Photonic crystal ring resonator based optical filters for photonic integrated circuits

International Nuclear Information System (INIS)

Robinson, S.

2014-01-01

In this paper, a two Dimensional (2D) Photonic Crystal Ring Resonator (PCRR) based optical Filters namely Add Drop Filter, Bandpass Filter, and Bandstop Filter are designed for Photonic Integrated Circuits (PICs). The normalized output response of the filters is obtained using 2D Finite Difference Time Domain (FDTD) method and the band diagram of periodic and non-periodic structure is attained by Plane Wave Expansion (PWE) method. The size of the device is minimized from a scale of few tens of millimeters to the order of micrometers. The overall size of the filters is around 11.4 μm × 11.4 μm which is highly suitable of photonic integrated circuits

The effect of fibre source on the numbers of some fibre-degrading bacteria of Arabian camel's (Camelus dromedarius) foregut origin.

Science.gov (United States)

Samsudin, Anjas Asmara; Wright, André-Denis; Al Jassim, Rafat

2014-10-01

The total bacterial community of Fibrobacter succinogenes and Ruminococcus flavefaciens in fibre-enriched culture of the foregut contents of 12 adult feral camels (Camelus dromedaries) fed on native vegetation in Australia was investigated using quantitative PCR. Foregut contents were collected postmortem, pooled and filtered before divided into two fractions. One fraction was used for extraction of DNA, while the other fraction was inoculated straight away into BM 10 contained filter paper (FP), cotton thread (CT) or neutral detergent fibre (NDF) as the sole carbohydrate sources in Hungate tubes. The tubes were incubated anaerobically at 39 °C for 1 week. After a near complete degradation of the FP and CT and extensive turbidity in the NDF, media subculturing was carried out into fresh media tubes. This was repeated twice before genomic DNA was extracted and used for quantification of bacteria. Using an absolute quantification method, the numbers of cells in 1 ml of each sample ranged from 4.07 × 10(6) to 2.73 × 10(9) for total bacteria, 1.34 × 10(3) to 2.17 × 10(5) for F. succinogenes and 5.78 × 10(1) to 3.53 × 10(4) for R. flavefaciens. The mean cell number of F. succinogenes was highest in the FP enrichment medium at approximately 107-fold, whereas for the R. flavefaciens targeted primer, the NDF enrichment media had the highest mean cell number at approximately 4-fold when compared to the rumen content. The data presented here provide evidence of fibre type preference by the two main fibre-degrading bacteria and would help us understand the interaction between fibre type and fibre-degrading microorganisms, which has ramification on camel nutrition at different seasons and environments.

Integration of a terahertz quantum cascade laser with a hollow waveguide

Science.gov (United States)

Wanke, Michael C [Albuquerque, NM; Nordquist, Christopher D [Albuquerque, NM

2012-07-03

The present invention is directed to the integration of a quantum cascade laser with a hollow waveguide on a chip to improve both the beam pattern and manufacturability. By coupling the QCL output into a single-mode rectangular waveguide the radiation mode structure can be known and the propagation, manipulation, and broadcast of the QCL radiation can then be entirely controlled by well-established rectangular waveguide techniques. By controlling the impedance of the interface, enhanced functions, such as creating amplifiers, efficient coupling to external cavities, and increasing power output from metal-metal THz QCLs, are also enabled.

Measurement of temperature profiles in process-applications using fibre-optical methods; Prozessgeeignete Temperaturprofilmessungen mit faseroptischen Methoden

Energy Technology Data Exchange (ETDEWEB)

Seefeld, P. [Endress und Hauser Wetzer GmbH und Co.KG, Nesselwang (Germany)

2008-07-01

Fibre-optical temperature measuring methods are offering an approach to detect temperature profiles. According to the NAMUR-Technology-Roadmap the detection of temperature profiles is representing an increased benefit. Intrinsic fibre-optical temperature measuring techniques are presented, known as OTDRmethod (Optical tine domain reflectometry) facilitating a distributed temperature measurement method that allows a resolution in the range of decimetres. For the purpose of such applications a suitable photoncounting device comprises mechanical robust fibre-optical components, 3 db Coupler, referenced Laser- Diode, Y-Coupler with integrated band-filter and APD (Avalanche Diode) used in a detection module. A VHDL-coded FBGA-board provides a basic control-device for - a Laser-Driver to generate adjustable exiting-pulses in the range of nanoseconds at rates up to 100 kHz. - a Photon-Counting module with a minimum opening width in the range of one nanosecond - that permits the co-addition of the photon-counts derived from the spectral resolved Stokes and Anti-Stokes band. (orig.)

Predicting optimal back-shock times in ultrafiltration hollow fiber modules II: Effect of inlet flow and concentration dependent viscosity

DEFF Research Database (Denmark)

Vinther, Frank; Pinelo, Manuel; Brøns, Morten

2015-01-01

This paper concerns mathematical modeling and computational fluid dynamics of back-shocking during hollow fibre ultrafiltration of dextran T500. In this paper we present a mathematical model based on first Principles, i.e., solving the Navier-Stokes equation along with the continuity equation...

Experimental demonstration of a ferroelectric liquid crystal tunable filter for fast demodulation of FBG sensors

Science.gov (United States)

Mathews, Sunish; Semenova, Yuliya; Rajan, Ginu; Farrell, Gerald

2009-05-01

A discretely tunable Surface-Stabilized Ferroelectric Liquid Crystal based Lyot Filter, with tuning speeds in the order of microseconds, is demonstrated experimentally as a channel dropper for the demodulation of multiple Fibre Bragg Grating sensors. The 3-stage Lyot Filter designed and experimentally verified can be used together with the high-speed ratiometric wavelength measurement system employing a fibre bend loss edge filter. Such systems can be used for the demodulation of distributed Fibre Bragg Grating sensors employed in applications such as structural monitoring, industrial sensing and haptic telerobotic surgical systems.

Fibre optic cable in the nuclear industry

International Nuclear Information System (INIS)

Roberts, Berwyn

1987-01-01

The uses of optical fibre cables to transmit light signals include medical applications and telecommunications. In the nuclear industry the applications include process control and monitoring, conventional datacoms, security fencing and sensors. Time division multiplexing is described and currently available fibre optic multipexers are listed and explained. Single and multimode fibres are mentioned. Fibre optics are also used in cryogenics, to monitor the integrity of the storage vessels for cryogenic liquids. The uses of fibre optics at Hartlepool, Heysham I and Torness are mentioned in particular. (UK)

Microstructured Optical Fibres

DEFF Research Database (Denmark)

1999-01-01

The present invention relates to a new class of optical waveguides, in which waveguiding along one or more core regions is obtained through the application of the Photonic Bandgap (PBG) effect. The invention further relates to optimised two-dimensional lattice structures capable of providing......, which are easy to manufacture. Finally, the present invention relates to a new fabrication technique, which allows easy manufacturing of preforms for photonic crystal fibers with large void filling fractions, as well as it allows a high flexibility in the design of the cladding and core structures....... complete PBGs, which reflects light incident from air or vacuum. Such structures may be used as cladding structures in optical fibres, where light is confined and thereby guided in a hollow core region. In addition, the present invention relates to designs for ultra low-loss PBG waveguiding structures...

Effect of age on the structural integrity of HEPA filters

International Nuclear Information System (INIS)

Johnson, J.S.; Beason, D.G.; Smith, P.R.; Gregory, W.S.

1989-01-01

All of the controls on high-efficiency particulate air (HEPA) filters are based on rigid manufacturing standards with regard to filtration efficiency, temperature performance, pressure integrity, and strength. Third-party inspection and testing by the US Department of Energy increases the reliability of new HEPA filters, but only routine in-place testing is used to assure that an aging filter performs adequately. In 1980 the Lawrence Livermore National Laboratory initiated a small evaluation to determine if age has a significant effect on the structural integrity of HEPA filters. A series of used uncontaminated filters dating back to 1965 was obtained for these tests. Tensile strength tests on the old media indicated a decrease in strength. To provide additional measurement of the filters' overall strength, several of these aged filters were subjected to pressure pulses equivalent to the NRC Region I tornado pulses and shock wave over pressures. Data from these tests indicate a decrease in breaking pressure of from 25-50%. A large increase in complete filter pack blow-out during the simulated NRC Region I tornado tests was also observed. The preliminary results indicate the need for an administrative lifetime for HEPA filters used in critical nuclear facilities. Due to the unique conditions in each facility, different administrative lifetimes may be necessary

Fabrication of polymeric hollow nanospheres, hollow nanocubes and hollow plates

Science.gov (United States)

Cheng, Daming; Xia, Haibing; Chan, Hardy Sze On

2006-03-01

A facile strategy for fabricating polypyrrole-chitosan (PPy-CS) hollow nanostructures with different shapes (sphere, cube and plate) and a wide range of sizes (from 35 to 600 nm) is described. These hollow structures have been fabricated using silver bromide as a single template material for polymer nucleation and growth. PPy-CS hollow nanostructures are formed by reaction with an etching agent to remove the core. These hollow nanostructures have been extensively characterized using various techniques such as TEM, FT-IR, UV-vis, and XRD.

Magnesium Coated Bioresorbable Phosphate Glass Fibres: Investigation of the Interface between Fibre and Polyester Matrices

Directory of Open Access Journals (Sweden)

Xiaoling Liu

2013-01-01

Full Text Available Bioresorbable phosphate glass fibre reinforced polyester composites have been investigated as replacement for some traditional metallic orthopaedic implants, such as bone fracture fixation plates. However, composites tested revealed loss of the interfacial integrity after immersion within aqueous media which resulted in rapid loss of mechanical properties. Physical modification of fibres to change fibre surface morphology has been shown to be an effective method to improve fibre and matrix adhesion in composites. In this study, biodegradable magnesium which would gradually degrade to Mg2+ in the human body was deposited via magnetron sputtering onto bioresorbable phosphate glass fibres to obtain roughened fibre surfaces. Fibre surface morphology after coating was observed using scanning electron microscope (SEM. The roughness profile and crystalline texture of the coatings were determined via atomic force microscope (AFM and X-ray diffraction (XRD analysis, respectively. The roughness of the coatings was seen to increase from 40±1 nm to 80±1 nm. The mechanical properties (tensile strength and modulus of fibre with coatings decreased with increased magnesium coating thickness.

Diffusion bonding of transition structures for integral aluminium-fibre reinforced polymer (FRP) compounds

Energy Technology Data Exchange (ETDEWEB)

Hehl, A. von [IWT - Stiftung Institut fuer Werkstofftechnik, Hauptabteilung Werkstofftechnik, Bremen (Germany); Syassen, F. [Airbus Operations GmbH, Metal Technology, Bremen (Germany); Schimanski, K.

2012-04-15

Components in hybrid design become more and more important in terms of their lightweight potential. In this context the demand for weight saving in aerospace leads to increasing numbers of applications of fibre composites for primary structural components. In consequence the use of FRP-metal compounds is necessary. Within the investigations of the researcher group ''Schwarz Silber'' (FOR 1224) founded by the DFG (German Research Foundation) material optimised interface structures for advanced CFRP-aluminium compounds are currently being studied. Within their work the researcher group focussed on three concepts realizing the transition structures: the usage of wires (titanium), foils (titanium) and fibres (glass fibre) as transition elements between CFRP and aluminium. For the connection of the aluminium sheet and the transition element die-casting and laser beam welding are basically used. As a possible alternative to the both liquid phase processes a feasibility study haven been done focussing the solid state processes diffusion bonding. The experimental results show the high potential of this process in view of the transferable loads for integral transition structures. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Polymer filters for ultraviolet-excited integrated fluorescence sensing

International Nuclear Information System (INIS)

Dandin, Marc; Abshire, Pamela; Smela, Elisabeth

2012-01-01

Optical filters for blocking ultraviolet (UV) light were fabricated by doping various polymer hosts with a UV absorbing chromophore. The polymers were polydimethylsiloxane (PDMS), a silicone elastomer frequently used in microfluidics, SU-8, a photopatternable epoxy, and Humiseal 1B66, an acrylic coating used for moisture protection of integrated circuits. The chromophore was 2-(2′-hydroxy-5′-methylphenyl) benzotriazole (BTA), which has a high extinction coefficient between 300 nm and 400 nm. We demonstrate filters 5 µm thick that exhibit high ultraviolet rejection (nearly −40 dB at 342 nm) yet pass visible light (near 0 dB above 400 nm), making them ideal for ultraviolet-excited fluorescence sensing within microsystems. The absorbance of the BTA depended on the host polymer. These filters are promising for integrated fluorescence spectroscopy in bioanalytical platforms because they can be patterned by dry etching, molding or exposure to ultraviolet light. (paper)

Hollow fibre-based liquid phase microextraction combined with high-performance liquid chromatography for the analysis of flavonoids in Echinophora platyloba DC. and Mentha piperita.

Science.gov (United States)

Hadjmohammadi, Mohammadreza; Karimiyan, Hanieh; Sharifi, Vahid

2013-11-15

A simple, inexpensive and efficient three phase hollow fibre liquid phase microextraction (HF-LPME) technique combined with HPLC was used for the simultaneous determination of flavonoids in Echinophora platyloba DC. and Mentha piperita. Different factors affecting the HF-LPME procedure were investigated and optimised. The optimised extraction conditions were as follows: 1-octanol as an organic solvent, pHdonor=2, pHacceptor=9.75, stirring rate of 1000rpm, extraction time of 80min, without addition of salt. Under these conditions, the enrichment factors ranged between 146 and 311. The values of intra and inter-day relative standard deviations (RSD) were in the range of 3.18-6.00% and 7.25-11.00%, respectively. The limits of detection (LODs) ranged between 0.5 and 7.0ngmL(-1). Among the investigated flavonoids quercetin was found in E. platyloba DC. and luteolin was found in M. piperita. Concentration of quercetin and luteolin was 0.015 and 0.025mgg(-1) respectively. Copyright © 2013 Elsevier Ltd. All rights reserved.

Deep Kalman Filter: Simultaneous Multi-Sensor Integration and Modelling; A GNSS/IMU Case Study.

Science.gov (United States)

Hosseinyalamdary, Siavash

2018-04-24

Bayes filters, such as the Kalman and particle filters, have been used in sensor fusion to integrate two sources of information and obtain the best estimate of unknowns. The efficient integration of multiple sensors requires deep knowledge of their error sources. Some sensors, such as Inertial Measurement Unit (IMU), have complicated error sources. Therefore, IMU error modelling and the efficient integration of IMU and Global Navigation Satellite System (GNSS) observations has remained a challenge. In this paper, we developed deep Kalman filter to model and remove IMU errors and, consequently, improve the accuracy of IMU positioning. To achieve this, we added a modelling step to the prediction and update steps of the Kalman filter, so that the IMU error model is learned during integration. The results showed our deep Kalman filter outperformed the conventional Kalman filter and reached a higher level of accuracy.

A Novel CPW BandPass Filter Integrating Periodic Rectangular Slot Cells

Directory of Open Access Journals (Sweden)

Fouad Aytouna

2015-12-01

Full Text Available In this paper, we introduce the design and the achievement of a Bandpass filter structure based on the use of rectangular slot cell. The originality of this work is to achieve a coplanar filter easy to integrate with microwave planar circuits and having a wide frequency bandwidth. The proposed bandpass filter is a low cost and compact planar filter structure. The final circuit is simulated by using two electromagnetic solvers, ADS and HFSS. The validation into simulation is based on using optimization methods integrated into the both solvers. Simulations have taken into account a high meshing density to cover the whole circuit. The fabricated bandpass filter has an area of 35X31mm2 and having a good insertion loss around -0.75dB in the bandwidth. The comparison between simulation and measurement results presents a good agreement.

Two Integrator Loop Filters: Generation Using NAM Expansion and Review

Directory of Open Access Journals (Sweden)

Ahmed M. Soliman

2010-01-01

Full Text Available Systematic synthesis method to generate a family of two integrator loop filters based on nodal admittance matrix (NAM expansion is given. Eight equivalent circuits are obtained; six of them are new. Each of the generated circuits uses two grounded capacitors and employs two current conveyors (CCII or two inverting current conveyors (ICCII or a combination of both. The NAM expansion is also used to generate eight equivalent grounded passive elements two integrator loop filters using differential voltage current conveyor (DVCC; six of them are new. Changing the input port of excitation, two new families of eight unity gain lowpass filter circuits each using two CCII or ICCII or combination of both or two DVCC are obtained.

On a New Family of Kalman Filter Algorithms for Integrated Navigation

Science.gov (United States)

Mahboub, V.; Saadatseresht, M.; Ardalan, A. A.

2017-09-01

Here we present a review on a new family of Kalman filter algorithms which recently developed for integrated navigation. In particular it is useful for vision based navigation due to the type of data. Here we mainly focus on three algorithms namely weighted Total Kalman filter (WTKF), integrated Kalman filter (IKF) and constrained integrated Kalman filter (CIKF). The common characteristic of these algorithms is that they can consider the neglected random observed quantities which may appear in the dynamic model. Moreover, our approach makes use of condition equations and straightforward variance propagation rules. The WTKF algorithm can deal with problems with arbitrary weight matrixes. Both of the observation equations and system equations can be dynamic-errors-in-variables (DEIV) models in the IKF algorithms. In some problems a quadratic constraint may exist. They can be solved by CIKF algorithm. Finally, we compare four algorithms WTKF, IKF, CIKF and EKF in numerical examples.

Deep Kalman Filter: Simultaneous Multi-Sensor Integration and Modelling; A GNSS/IMU Case Study

Directory of Open Access Journals (Sweden)

Siavash Hosseinyalamdary

2018-04-01

Full Text Available Bayes filters, such as the Kalman and particle filters, have been used in sensor fusion to integrate two sources of information and obtain the best estimate of unknowns. The efficient integration of multiple sensors requires deep knowledge of their error sources. Some sensors, such as Inertial Measurement Unit (IMU, have complicated error sources. Therefore, IMU error modelling and the efficient integration of IMU and Global Navigation Satellite System (GNSS observations has remained a challenge. In this paper, we developed deep Kalman filter to model and remove IMU errors and, consequently, improve the accuracy of IMU positioning. To achieve this, we added a modelling step to the prediction and update steps of the Kalman filter, so that the IMU error model is learned during integration. The results showed our deep Kalman filter outperformed the conventional Kalman filter and reached a higher level of accuracy.

Low cost Polymer Optical Fibre based transmission system for feeding integrated broadband wireless in-house LANs

NARCIS (Netherlands)

Ng'Oma, A.; Koonen, A.M.J.; Tafur Monroy, I.; Boom, van den H.P.A.; Smulders, P.F.M.; Khoe, G.D.; Visser, D. Taco; Lenstra, Daan; Schouten, F. Hugo

2002-01-01

A bi-directional transmission system using low cost Polymer Optical Fibre (POF) to feed the required large number of radio access points in next-generation integrated broadband wireless in-house LANs is proposed. Results from simulations and experiments show that, by tuning system parameters, a

Plant fibre composites - porosity and volumetric interaction

DEFF Research Database (Denmark)

Madsen, Bo; Thygesen, Anders; Lilholt, Hans

2007-01-01

the combination of a high fibre volume fraction, a low porosity and a high composite density is optimal. Experimental data from the literature on volumetric composition and density of four types of plant fibre composites are used to validate the model. It is demonstrated that the model provides a concept......Plant fibre composites contain typically a relative large amount of porosity, which considerably influences properties and performance of the composites. The large porosity must be integrated in the conversion of weight fractions into volume fractions of the fibre and matrix parts. A model...... is presented to predict the porosity as a function of the fibre weight fractions, and to calculate the related fibre and matrix volume fractions, as well as the density of the composite. The model predicts two cases of composite volumetric interaction separated by a transition fibre weight fraction, at which...

FibreBags vs. FibreCaps for acid and neutral detergent fibre analysis

OpenAIRE

Koivisto , Jason

2003-01-01

International audience; A new procedure for determining acid detergent fibre and neutral detergent fibre (ADF and NDF) was developed to reduce the need for filtration and to allow for batch processing of forage samples. The FibreBag system is an economically necessary evolution of the earlier FibreCap system. The purpose of this enquiry was to determine if the FibreBag is a suitable replacement for the FibreCap. The FibreBag method produced very similar results to the FibreCap system of analy...

Numerical investigation of a tunable band-pass plasmonic filter with a hollow-core ring resonator

International Nuclear Information System (INIS)

Setayesh, Amir; Mirnaziry, S Reza; Abrishamian, Mohammad Sadegh

2011-01-01

In this study, a compact nanoscale plasmonic filter which consists of two metal–insulator–metal (MIM) waveguides coupled to each other by a rectangular ring resonator is presented and investigated numerically. The propagating modes of surface plasmon polaritons (SPPs) are studied in this structure. By replacing a portion of the ring core with air, while the outer dimensions of the structure are kept constant, we illustrate the possibility of the redshift of resonant wavelengths in order to tune the resonance modes. This feature is useful for integrated circuits in which we have limitations on the outer dimensions of the filter structure and it is not possible to enlarge the dimension of the ring resonator to reach longer resonant wavelengths. The corresponding results are illustrated by the 2D finite-difference time-domain (FDTD) method. The proposed structure has potential applications in plasmonic integrated circuits and can be simply fabricated

Numerical investigation of a tunable band-pass plasmonic filter with a hollow-core ring resonator

Science.gov (United States)

Setayesh, Amir; Mirnaziry, S. Reza; Sadegh Abrishamian, Mohammad

2011-03-01

In this study, a compact nanoscale plasmonic filter which consists of two metal-insulator-metal (MIM) waveguides coupled to each other by a rectangular ring resonator is presented and investigated numerically. The propagating modes of surface plasmon polaritons (SPPs) are studied in this structure. By replacing a portion of the ring core with air, while the outer dimensions of the structure are kept constant, we illustrate the possibility of the redshift of resonant wavelengths in order to tune the resonance modes. This feature is useful for integrated circuits in which we have limitations on the outer dimensions of the filter structure and it is not possible to enlarge the dimension of the ring resonator to reach longer resonant wavelengths. The corresponding results are illustrated by the 2D finite-difference time-domain (FDTD) method. The proposed structure has potential applications in plasmonic integrated circuits and can be simply fabricated.

Progress towards the use of disposable filters

International Nuclear Information System (INIS)

Macphail, I.

1979-08-01

Thermally degradable materials have been evaluated for service in HEPA filter units used to filter gases from active plants. The motivation was to reduce the bulk storage problems of contaminated filters by thermal decomposition to gaseous products and a solid residue substantially comprised of the filtered particulates. It is shown that while there are no commercially available alternatives to the glass fibre used in the filter medium, it would be feasible to manufacture the filter case and spacers from materials which could be incinerated. Operating temperatures, costs and the type of residues for disposal are discussed for filter case materials. (U.K.)

A New Adaptive H-Infinity Filtering Algorithm for the GPS/INS Integrated Navigation

Science.gov (United States)

Jiang, Chen; Zhang, Shu-Bi; Zhang, Qiu-Zhao

2016-01-01

The Kalman filter is an optimal estimator with numerous applications in technology, especially in systems with Gaussian distributed noise. Moreover, the adaptive Kalman filtering algorithms, based on the Kalman filter, can control the influence of dynamic model errors. In contrast to the adaptive Kalman filtering algorithms, the H-infinity filter is able to address the interference of the stochastic model by minimization of the worst-case estimation error. In this paper, a novel adaptive H-infinity filtering algorithm, which integrates the adaptive Kalman filter and the H-infinity filter in order to perform a comprehensive filtering algorithm, is presented. In the proposed algorithm, a robust estimation method is employed to control the influence of outliers. In order to verify the proposed algorithm, experiments with real data of the Global Positioning System (GPS) and Inertial Navigation System (INS) integrated navigation, were conducted. The experimental results have shown that the proposed algorithm has multiple advantages compared to the other filtering algorithms. PMID:27999361

Mixed-integrator-based bi-quad cell for designing a continuous time filter

International Nuclear Information System (INIS)

Chen Yong; Zhou Yumei

2010-01-01

A new mixed-integrator-based bi-quad cell is proposed. An alternative synthesis mechanism of complex poles is proposed compared with source-follower-based bi-quad cells which is designed applying the positive feedback technique. Using the negative feedback technique to combine different integrators, the proposed bi-quad cell synthesizes complex poles for designing a continuous time filter. It exhibits various advantages including compact topology, high gain, no parasitic pole, no CMFB circuit, and high capability. The fourth-order Butterworth lowpass filter using the proposed cells has been fabricated in 0.18 μm CMOS technology. The active area occupied by the filter with test buffer is only 200 x 170 μm 2 . The proposed filter consumes a low power of 201 μW and achieves a 68.5 dB dynamic range. (semiconductor integrated circuits)

Hybrid extended particle filter (HEPF) for integrated inertial navigation and global positioning systems

International Nuclear Information System (INIS)

Aggarwal, Priyanka; Syed, Zainab; El-Sheimy, Naser

2009-01-01

Navigation includes the integration of methodologies and systems for estimating time-varying position, velocity and attitude of moving objects. Navigation incorporating the integrated inertial navigation system (INS) and global positioning system (GPS) generally requires extensive evaluations of nonlinear equations involving double integration. Currently, integrated navigation systems are commonly implemented using the extended Kalman filter (EKF). The EKF assumes a linearized process, measurement models and Gaussian noise distributions. These assumptions are unrealistic for highly nonlinear systems like land vehicle navigation and may cause filter divergence. A particle filter (PF) is developed to enhance integrated INS/GPS system performance as it can easily deal with nonlinearity and non-Gaussian noises. In this paper, a hybrid extended particle filter (HEPF) is developed as an alternative to the well-known EKF to achieve better navigation data accuracy for low-cost microelectromechanical system sensors. The results show that the HEPF performs better than the EKF during GPS outages, especially when simulated outages are located in periods with high vehicle dynamics

Optimization of Recycled Glass Fibre-Reinforced Plastics Gear via Integration of the Taguchi Method and Grey Relational Analysis

Science.gov (United States)

Mizamzul Mehat, Nik; Syuhada Zakarria, Noor; Kamaruddin, Shahrul

2018-03-01

The increase in demand for industrial gears has resulted in the increase in usage of plastic-matrix composites particularly glass fibre-reinforced plastics as the gear materials. The usage of these synthetic fibers is to enhance the mechanical strength and the thermal resistance of the plastic gears. Nevertheless, the production of large quantities of these synthetic fibre-reinforced composites poses a serious threat to the ecosystem. Comprehending to this fact, the present work aimed at investigating the effects of incorporating recycled glass fibre-reinforced plastics in various compositions particularly on dimensional stability and mechanical properties of gear produced with diverse injection moulding processing parameters setting. The integration of Grey relational analysis (GRA) and Taguchi method was adopted to evaluate the influence of recycled glass fibre-reinforced plastics and variation in processing parameters on gear quality. From the experimental results, the blending ratio was found as the most influential parameter of 56.0% contribution in both improving tensile properties as well as in minimizing shrinkage, followed by mould temperature of 24.1% contribution and cooling time of 10.6% contribution. The results obtained from the aforementioned work are expected to contribute to accessing the feasibility of using recycled glass fibre-reinforced plastics especially for gear application.

IAE-adaptive Kalman filter for INS/GPS integrated navigation system

Institute of Scientific and Technical Information of China (English)

Bian Hongwei; Jin Zhihua; Tian Weifeng

2006-01-01

A marine INS/GPS adaptive navigation system is presented in this paper. GPS with two antenna providing vessel's altitude is selected as the auxiliary system fusing with INS to improve the performance of the hybrid system. The Kalman filter is the most frequently used algorithm in the integrated navigation system, which is capable of estimating INS errors online based on the measured errors between INS and GPS. The standard Kalman filter (SKF) assumes that the statistics of the noise on each sensor are given. As long as the noise distributions do not change, the Kalman filter will give the optimal estimation. However GPS receiver will be disturbed easily and thus temporally changing measurement noise will join into the outputs of GPS, which will lead to performance degradation of the Kalman filter. Many researchers introduce fuzzy logic control method into innovation-based adaptive estimation adaptive Kalman filtering (IAE-AKF) algorithm, and accordingly propose various adaptive Kalman filters. However how to design the fuzzy logic controller is a very complicated problem still without a convincing solution. A novel IAE-AKF is proposed herein, which is based on the maximum likelihood criterion for the proper computation of the filter innovation covariance and hence of the filter gain. The approach is direct and simple without having to establish fuzzy inference rules. After having deduced the proposed IAE-AKF algorithm theoretically in detail, the approach is tested by the simulation based on the system error model of the developed INS/GPS integrated marine navigation system. Simulation results show that the adaptive Kalman filter outperforms the SKF with higher accuracy, robustness and less computation. It is demonstrated that this proposed approach is a valid solution for the unknown changing measurement noise exited in the Kalman filter.

Filter element, particularly for cleaning hot gases

International Nuclear Information System (INIS)

Hoelter, H.

1980-01-01

The fibres of the filter cloth consists of aluminium silicate. The filter cloth lies on a mesh made of ceramic material, e.g. 99% SiO 2 and 1% Cr 2 O 3 . In order to reduce the bending stress at the edges of the filter cloth, particularly when cleaning, there are bend protection devices in the form of curved surfaces made of felt or similar material in the edge areas. (DG) [de

10 years of make-up water treatment with integrated reverse osmosis at Grosskraftwerk Mannheim

International Nuclear Information System (INIS)

Spindler, K.; Bloechl, H.; Bursik, A.

1993-01-01

Since 1982, at Grosskraftwerk Mannheim, a make-up water treatment in which three reverse osmosis plants are integrated, has been operating. The original high-pressure hollow fibre module of these plants has been replaced by low-pressure coil modules. The reasons for the change in system are described in the paper. In the low-pressure plant, coil modules have been installed by several manufacturers. The paper reports on experience with the low-pressure elements. The experience gained has been streamed into the planning proposals for the new make-up water treatment plant. (orig.) [de

Electromagnetic design methods in systems-on-chip: integrated filters for wireless CMOS RFICs

International Nuclear Information System (INIS)

Contopanagos, Harry

2005-01-01

We present general methods for designing on-chip CMOS passives and utilizing these integrated elements to design on-chip CMOS filters for wireless communications. These methods rely on full-wave electromagnetic numerical calculations that capture all the physics of the underlying foundry technologies. This is especially crucial for deep sub-micron CMOS technologies as it is important to capture the physical effects of finite (and mediocre) Q-factors limited by material losses and constraints on expensive die area, low self-resonance frequencies and dual parasitics that are particularly prevalent in deep sub-micron CMOS processes (65 nm-0.18 μm. We use these integrated elements in an ideal synthesis of a Bluetooth/WLAN pass-band filter in single-ended or differential architectures, and show the significant deviations of the on-chip filter response from the ideal one. We identify which elements in the filter circuit need to maximize their Q-factors and which Q-factors do not affect the filter performance. This saves die area, and predicts the FET parameters (especially transconductances) and negative-resistance FET topologies that have to be integrated in the filter to restore its performance. (invited paper)

Electromagnetic design methods in systems-on-chip: integrated filters for wireless CMOS RFICs

Energy Technology Data Exchange (ETDEWEB)

Contopanagos, Harry [Institute for Microelectronics, NCSR ' Demokritos' , PO Box 60228, GR-153 10 Aghia Paraskevi, Athens (Greece)

2005-01-01

We present general methods for designing on-chip CMOS passives and utilizing these integrated elements to design on-chip CMOS filters for wireless communications. These methods rely on full-wave electromagnetic numerical calculations that capture all the physics of the underlying foundry technologies. This is especially crucial for deep sub-micron CMOS technologies as it is important to capture the physical effects of finite (and mediocre) Q-factors limited by material losses and constraints on expensive die area, low self-resonance frequencies and dual parasitics that are particularly prevalent in deep sub-micron CMOS processes (65 nm-0.18 {mu}m. We use these integrated elements in an ideal synthesis of a Bluetooth/WLAN pass-band filter in single-ended or differential architectures, and show the significant deviations of the on-chip filter response from the ideal one. We identify which elements in the filter circuit need to maximize their Q-factors and which Q-factors do not affect the filter performance. This saves die area, and predicts the FET parameters (especially transconductances) and negative-resistance FET topologies that have to be integrated in the filter to restore its performance. (invited paper)

Bds/gps Integrated Positioning Method Research Based on Nonlinear Kalman Filtering

Science.gov (United States)

Ma, Y.; Yuan, W.; Sun, H.

2017-09-01

In order to realize fast and accurate BDS/GPS integrated positioning, it is necessary to overcome the adverse effects of signal attenuation, multipath effect and echo interference to ensure the result of continuous and accurate navigation and positioning. In this paper, pseudo-range positioning is used as the mathematical model. In the stage of data preprocessing, using precise and smooth carrier phase measurement value to promote the rough pseudo-range measurement value without ambiguity. At last, the Extended Kalman Filter(EKF), the Unscented Kalman Filter(UKF) and the Particle Filter(PF) algorithm are applied in the integrated positioning method for higher positioning accuracy. The experimental results show that the positioning accuracy of PF is the highest, and UKF is better than EKF.

Plant fibre composites - porosity and stiffness

DEFF Research Database (Denmark)

Madsen, Bo; Thygesen, Anders; Lilholt, Hans

2009-01-01

Plant fibre composites contain typically a relatively large amount of porosity which influences their performance. A model, based on a modified rule of mixtures, is presented to include the influence of porosity on the composite stiffness. The model integrates the volumetric composition...... of the composites with their mechanical properties. The fibre weight fraction is used as an independent parameter to calculate the complete volumetric composition. A maximum obtainable stiffness of the composites is calculated at a certain transition fibre weight fraction, which is characterised by a best possible...... combination of high fibre volume fraction and low porosity. The model is validated with experimental data from the literature on several types of composites. A stiffness diagram is presented to demonstrate that the calculations can be used for tailoring and design of composites with a given profile...

Gyrospun antimicrobial nanoparticle loaded fibrous polymeric filters

Energy Technology Data Exchange (ETDEWEB)

Eranka Illangakoon, U.; Mahalingam, S.; Wang, K. [Department of Mechanical Engineering, University College London, London WC1E 7JE (United Kingdom); Cheong, Y.-K. [School of Engineering and Technology, University of Hertfordshire, Hatfield AL10 9AB (United Kingdom); Canales, E. [Department of Civil, Environmental and Geomatic Engineering, University College London, London WC1E 7JE (United Kingdom); Ren, G.G. [School of Engineering and Technology, University of Hertfordshire, Hatfield AL10 9AB (United Kingdom); Cloutman-Green, E. [Department of Microbiology, Virology, and Infection Prevention Control, Great Ormond Street Hospital NHS Foundation Trust, London WCIN 3JH (United Kingdom); Edirisinghe, M., E-mail: m.edirisinghe@ucl.ac.uk [Department of Mechanical Engineering, University College London, London WC1E 7JE (United Kingdom); Ciric, L. [Department of Civil, Environmental and Geomatic Engineering, University College London, London WC1E 7JE (United Kingdom)

2017-05-01

A one step approach to prepare hybrid nanoparticle embedded polymer fibres using pressurised gyration is presented. Two types of novel antimicrobial nanoparticles and poly(methylmethacrylate) polymer were used in this work. X-ray diffraction analysis of the nanoparticles revealed Ag, Cu and W are the main elements present in them. The concentration of the polymer solution and the nanoparticle concentration had a significant influence on the fibre diameter, pore size and morphology. Fibres with a diameter in the range of 6–20 μm were spun using 20 wt% polymer solutions containing 0.1, 0.25 and 0.5 wt% nanoparticles under 0.3 MPa working pressure and a rotational speed of 36,000 rpm. Continuous, bead-free fibre morphologies were obtained for each case. The pore size in the fibres varied between 36 and 300 nm. Successful incorporation of the nanoparticles in polymer fibres was confirmed by energy dispersive x-ray analysis. The fibres were also gyrospun on to metallic discs to prepare filters which were tested for their antibacterial activity on a suspension of Pseudomonas aeruginosa. Nanoparticle loaded fibres showed higher antibacterial efficacy than pure poly(methylmethacrylate) fibres. - Highlights: • Nanoparticles containing Ag, Cu and W were studied for antimicrobial activity. • Hybrid nanoparticle-polymeric fibres were prepared using pressurised gyration. • Fibre characteristics were tailored using material and forming process variables. • Nanoparticle loaded fibre mats show higher antibacterial efficacy.

High-performance supercapacitors of carboxylate-modified hollow carbon nanospheres coated on flexible carbon fibre paper: Effects of oxygen-containing group contents, electrolytes and operating temperature

International Nuclear Information System (INIS)

Phattharasupakun, Nutthaphon; Wutthiprom, Juthaporn; Suktha, Phansiri; Iamprasertkun, Pawin; Chanlek, Narong; Shepherd, Celine; Hadzifejzovic, Emina; Moloney, Mark G.; Foord, John S.; Sawangphruk, Montree

2017-01-01

Although functionalized carbon-based materials have been widely used as the supercapacitor electrodes, the optimum contents of the functional groups, the charge storage mechanisms, and the effects of electrolytes and operating temperature have not yet been clearly investigated. In this work, carboxylate-modified hollow carbon nanospheres (c-HCN) with different functional group contents synthesized by an oxidation process of carbon nanospheres with nitric acid were coated on flexible carbon fibre paper and used as the supercapacitor electrodes. An as-fabricated supercapacitor of the c-HCN with a finely tuned 6.2 atomic % of oxygen of the oxygen-containing groups in an ionic liquid electrolyte exhibits a specific capacitance of 390 F g"−"1, a specific energy of 115 Wh kg"−"1, and a maximum specific power of 13548 W kg"−"1 at 70 °C. The charge storage mechanism investigated is based on the chemical adsorption of the ionic liquid electrolyte on the c-HCN electrode. This process is highly reversible leading to high capacity retention. The supercapacitor in this work may be practically used in many high energy and power applications.

Design of low noise class D amplifiers using an integrated filter

International Nuclear Information System (INIS)

Wang Haishi; Zhang Bo

2012-01-01

This paper investigates the noise sources in a single-ended class D amplifier (SECDA) and suggests corresponding ways to lower the noise. The total output noise could be expressed as a function of the gain and noises from different sources. According to the function, the bias voltage (V B ) is a primary noise source, especially for a SECDA with a large gain. A low noise SECDA is obtained by integrating a filter into the SECDA to lower the noise of the V B . The filter utilizes an active resister and an 80 pF capacitance to get a 3 Hz pole. A noise test and fast Fourier transform analysis show that the noise performance of this SECDA is the same as that of a SECDA with an external filter. (semiconductor integrated circuits)

Nuclear fallout shelter

International Nuclear Information System (INIS)

Elton, J.

1982-01-01

A nuclear fallout shelter, to be buried below ground level exposing only an access hatch with a cover and ventilators, is constructed of two preformed hollow end sections connected by one or more preformed hollow tubular intermediate sections. The ventilators include a filter for removing radioactive particles from the air entering the shelter. The sections may be moulded shells of glass fibre reinforced plastics material having inwardly directed peripheral end flanges to enable the sections to be bolted together from inside the shelter after they have been positioned in an excavated trench. (author)

Effects of humidity and filter material on diffusive sampling of isocyanates using reagent-coated filters

NARCIS (Netherlands)

Henneken, H.; Vogel, M.; Karst, U.

2006-01-01

Diffusive sampling of methyl isocyanate (MIC) on 4-nitro-7-piperazinobenzo-2-oxa-1,3-diazole (NBDPZ)-coated glass fibre (GF) filters is strongly affected by high relative humidity (RH) conditions. It is shown that the humidity interference is a physical phenomenon, based on displacement of reagent

An Improved Strong Tracking Cubature Kalman Filter for GPS/INS Integrated Navigation Systems.

Science.gov (United States)

Feng, Kaiqiang; Li, Jie; Zhang, Xi; Zhang, Xiaoming; Shen, Chong; Cao, Huiliang; Yang, Yanyu; Liu, Jun

2018-06-12

The cubature Kalman filter (CKF) is widely used in the application of GPS/INS integrated navigation systems. However, its performance may decline in accuracy and even diverge in the presence of process uncertainties. To solve the problem, a new algorithm named improved strong tracking seventh-degree spherical simplex-radial cubature Kalman filter (IST-7thSSRCKF) is proposed in this paper. In the proposed algorithm, the effect of process uncertainty is mitigated by using the improved strong tracking Kalman filter technique, in which the hypothesis testing method is adopted to identify the process uncertainty and the prior state estimate covariance in the CKF is further modified online according to the change in vehicle dynamics. In addition, a new seventh-degree spherical simplex-radial rule is employed to further improve the estimation accuracy of the strong tracking cubature Kalman filter. In this way, the proposed comprehensive algorithm integrates the advantage of 7thSSRCKF’s high accuracy and strong tracking filter’s strong robustness against process uncertainties. The GPS/INS integrated navigation problem with significant dynamic model errors is utilized to validate the performance of proposed IST-7thSSRCKF. Results demonstrate that the improved strong tracking cubature Kalman filter can achieve higher accuracy than the existing CKF and ST-CKF, and is more robust for the GPS/INS integrated navigation system.

Substrate Integrated Evanescent Filters Employing Coaxial Stubs

DEFF Research Database (Denmark)

Zhurbenko, Vitaliy

2015-01-01

Evanescent mode substrate integrated waveguide (SIW) is one of the promising technologies for design of light-weight low-cost microwave components. Traditional realization methods used in the standard evanescent waveguide technology are often not directly applicable to SIW due to dielectric filli...... of the microwave filter are discussed. The approach is useful in applications where a sharp roll-off at the upper stop-band is required....

Studies on pulsed hollow cathode capillary discharges

Energy Technology Data Exchange (ETDEWEB)

Choi, P; Dumitrescu-Zoita, C; Larour, J; Rous, J [Ecole Polytechnique, 91 - Palaiseau (France). Lab. de Physique des Milieux Ionises; Favre, M; Moreno, J; Chuaqui, H; Wyndham, E [Pontificia Univ. Catolica de Chile, Santiago (Chile). Facultad de Fisica; Zambra, M [Comision Chilena de Energia Nuclear, Santiago (Chile); Wong, C S [Univ. of Malaya, Kuala Lumpur (Malaysia). Plasma Research Lab

1997-12-31

Preliminary results on radiation characteristics of pulsed hollow cathode capillary discharges are presented. The device combines the on axis electron beam assisted ionization capabilities of the transient hollow cathode discharge with a novel high voltage low inductance geometrical design, which integrates the local energy storage into the electrode system. A nanosecond regime high temperature plasma is produced in a long, high aspect ratio capillary, with light emission in the UV to XUV region. The discharge is operated from near vacuum to pressure in the 1000 mTorr range. (author). 2 figs., 7 refs.

Mode conversion in magneto photonic crystal fibre

International Nuclear Information System (INIS)

Otmani, Hamza; Bouchemat, Mohamed; Hocini, Abdesselam; Boumaza, Touraya; Benmerkhi, Ahlem

2017-01-01

The first concept of an integrated isolator was based on nonreciprocal TE–TM mode conversion, the nonreciprocal coupling between these modes is caused by the Faraday rotation if the magnetization is aligned along the z–axis, parallel to mode propagation. We propose to study this magneto-optical phenomenon, by the simulation of magneto photonic crystal fibre (MPCF), it consists of a periodic triangular lattice of air-holes filled with magnetic fluid which consists of magnetic nanoparticles into a BIG (Bismuth Iron Garnet) fibre. We simulated the influence of gyrotropy and the wavelength, and calculated Faraday rotation and modal birefringence. In this fibre the light is guided by internal total reflection, like classical fibres. However it was shown that they could function on a mode conversion much stronger than conventional fibres. - Highlights: • We propose to study mode conversion TE–TM, by the simulation of magneto photonic crystal fibre (MPCF). • We simulated the influence of gyrotropy. • We simulated the wavelength. • We calculated Faraday rotation. • We calculated modal birefringence.

iHWG-μNIR: a miniaturised near-infrared gas sensor based on substrate-integrated hollow waveguides coupled to a micro-NIR-spectrophotometer.

Science.gov (United States)

Rohwedder, J J R; Pasquini, C; Fortes, P R; Raimundo, I M; Wilk, A; Mizaikoff, B

2014-07-21

A miniaturised gas analyser is described and evaluated based on the use of a substrate-integrated hollow waveguide (iHWG) coupled to a microsized near-infrared spectrophotometer comprising a linear variable filter and an array of InGaAs detectors. This gas sensing system was applied to analyse surrogate samples of natural fuel gas containing methane, ethane, propane and butane, quantified by using multivariate regression models based on partial least square (PLS) algorithms and Savitzky-Golay 1(st) derivative data preprocessing. The external validation of the obtained models reveals root mean square errors of prediction of 0.37, 0.36, 0.67 and 0.37% (v/v), for methane, ethane, propane and butane, respectively. The developed sensing system provides particularly rapid response times upon composition changes of the gaseous sample (approximately 2 s) due the minute volume of the iHWG-based measurement cell. The sensing system developed in this study is fully portable with a hand-held sized analyser footprint, and thus ideally suited for field analysis. Last but not least, the obtained results corroborate the potential of NIR-iHWG analysers for monitoring the quality of natural gas and petrochemical gaseous products.

Investigation on filter method for smoothing spiral phase plate

Science.gov (United States)

Zhang, Yuanhang; Wen, Shenglin; Luo, Zijian; Tang, Caixue; Yan, Hao; Yang, Chunlin; Liu, Mincai; Zhang, Qinghua; Wang, Jian

2018-03-01

Spiral phase plate (SPP) for generating vortex hollow beams has high efficiency in various applications. However, it is difficult to obtain an ideal spiral phase plate because of its continuous-varying helical phase and discontinued phase step. This paper describes the demonstration of continuous spiral phase plate using filter methods. The numerical simulations indicate that different filter method including spatial domain filter, frequency domain filter has unique impact on surface topography of SPP and optical vortex characteristics. The experimental results reveal that the spatial Gaussian filter method for smoothing SPP is suitable for Computer Controlled Optical Surfacing (CCOS) technique and obtains good optical properties.

Nb2O5 hollow nanospheres as anode material for enhanced performance in lithium ion batteries

International Nuclear Information System (INIS)

Sasidharan, Manickam; Gunawardhana, Nanda; Yoshio, Masaki; Nakashima, Kenichi

2012-01-01

Graphical abstract: Nb 2 O 5 hollow nanosphere constructed electrode delivers high capacity of 172 mAh g −1 after 250 cycles and maintains structural integrity and excellent cycling stability. Highlights: ► Nb 2 O 5 hollow nanospheres synthesis was synthesized by soft-template. ► Nb 2 O 5 hollow nanospheres were investigated as anode material in Li-ion battery. ► Nanostructured electrode delivers high capacity of 172 mAh g −1 after 250 cycles. ► The electrode maintains the structural integrity and excellent cycling stability. ► Nanosized shell domain facilitates fast lithium intercalation/deintercalation. -- Abstract: Nb 2 O 5 hollow nanospheres of average diameter ca. ∼29 nm and hollow cavity size ca. 17 nm were synthesized using polymeric micelles with core–shell–corona architecture under mild conditions. The hollow particles were thoroughly characterized by transmission electron microscope (TEM), X-ray diffraction (XRD), infrared spectroscopy (FTIR), thermal (TG/DTA) and nitrogen adsorption analyses. Thus obtained Nb 2 O 5 hollow nanospheres were investigated as anode materials for lithium ion rechargeable batteries for the first time. The nanostructured electrode delivers high capacity of 172 mAh g −1 after 250 cycles of charge/discharge at a rate of 0.5 C. More importantly, the hollow particles based electrodes maintains the structural integrity and excellent cycling stability even after exposing to high current density 6.25 A g −1 . The enhanced electrochemical behavior is ascribed to hollow cavity coupled with nanosized Nb 2 O 5 shell domain that facilitates fast lithium intercalation/deintercalation kinetics.

Fibre and components induced limitations in high capacity optical networks

DEFF Research Database (Denmark)

Peucheret, Christophe

2003-01-01

The design of future all-optical networks relies on the knowledge of the physical layer transport properties. In this thesis, we focus on two types of system impairments: those induced by the non-ideal transfer functions of optical filters to be found in network elements such as optical add...... design in order to maximise the spectral efficiency in a four add-drop node ring network. The concept of "normalised transmission sections" is introduced in order to ease the dimensioning of transparent domains in future all-optical networks. Normalised sections based on standard single mode fibre (SMF......-drop multiplexers (OADM) and optical cross-connects (OXC), as well as those due to the interaction of group-velocity dispersion, optical fibre non-linearities and accumulation of amplifier noise in the transmission path. The dispersion of fibre optics components is shown to limit their cascadability. Dispersion...

Varactor-tuned Substrate Integrated Evanescent Filter

DEFF Research Database (Denmark)

Zhurbenko, Vitaliy; Acar, Öncel; Dong, Yunfeng

Evanescent mode waveguides allow for more compact microwave component design in comparison to the traditional fundamental mode waveguide technology. Evanescent waveguides can be integrated into a dielectric substrate in order to further reduce the mass and volume. Unfortunately, traditional...... realization methods used in the standard evanescent waveguides are often not directly applicable to substrate integrated waveguide (SIW) technology due to dielectric filling and small height of the waveguide. In this work, one of the realization methods of evanescent waveguides using lumped elements...... is considered. In contrast to other methods described in the literature, it avoids etching split ring resonators in the metal layer of the SIW. The filters presented here use varactors as tuning elements. The varactors (as well as DC decoupling circuits) are mounted on the surface of PCB bringing the lower...

Development and implementation of an automatic integration system for fibre optic sensors in the braiding process with the objective of online-monitoring of composite structures

Science.gov (United States)

Hufenbach, W.; Gude, M.; Czulak, A.; Kretschmann, Martin

2014-04-01

Increasing economic, political and ecological pressure leads to steadily rising percentage of modern processing and manufacturing processes for fibre reinforced polymers in industrial batch production. Component weights beneath a level achievable by classic construction materials, which lead to a reduced energy and cost balance during product lifetime, justify the higher fabrication costs. However, complex quality control and failure prediction slow down the substitution by composite materials. High-resolution fibre-optic sensors (FOS), due their low diameter, high measuring point density and simple handling, show a high applicability potential for an automated sensor-integration in manufacturing processes, and therefore the online monitoring of composite products manufactured in industrial scale. Integrated sensors can be used to monitor manufacturing processes, part tests as well as the component structure during product life cycle, which simplifies allows quality control during production and the optimization of single manufacturing processes.[1;2] Furthermore, detailed failure analyses lead to a enhanced understanding of failure processes appearing in composite materials. This leads to a lower wastrel number and products of a higher value and longer product life cycle, whereby costs, material and energy are saved. This work shows an automation approach for FOS-integration in the braiding process. For that purpose a braiding wheel has been supplemented with an appliance for automatic sensor application, which has been used to manufacture preforms of high-pressure composite vessels with FOS-networks integrated between the fibre layers. All following manufacturing processes (vacuum infiltration, curing) and component tests (quasi-static pressure test, programmed delamination) were monitored with the help of the integrated sensor networks. Keywords: SHM, high-pressure composite vessel, braiding, automated sensor integration, pressure test, quality control, optic-fibre

The design and construction of large diameter pre-filter packed recovery wells at the Ninth Avenue Superfund Site

International Nuclear Information System (INIS)

Lombardo, S.L.; Maley, T.J.; Bono, B.A.

1992-01-01

Large diameter groundwater/oil recovery wells were installed in an unconfined sand aquifer at the Ninth Avenue Superfund Site in Gary, Indiana. To assure adequate filter packs, prefilter packed groundwater/oil recovery wells were selected to minimize silting by using appropriate screen slot size and filter pack. A properly sized filter pack was necessary to prevent the formation material from entering the well. During field drilling operations, open-quotes having sandsclose quotes and silting of existing wells were encountered. By using sieve analyses of the native aquifer soil, described by Driscoll (1989), the filter pack and screen slot size were selected. Prefilter packed well screens were selected for this site to assure the presence of a uniform filter pack, thus minimizing siltation in the wells. A prefilter packed well screen consists of a double screen with the interstitial space filled with granular filter pack material designed specifically for site conditions. These wells provide the adequate filter pack without the need to add additional filter pack material outside the well screen. Wells were installed using 12 1/4 inch ID hollow stem augers. This methodology is EPA-approved, expeditious, and inexpensive. Level B personal protective equipment was required during installation. Therefore, the advantages of hollow stem drilling include short drilling time and no circulation fluids. The 14 recovery wells were successfully installed in 14 days using the hollow stem auger drilling technique. Observations during well development revealed little or no silt present in purged groundwater

Scanners for the quality contol of scintillating plastic fibres

CERN Document Server

Rodigues, Ana Barbara; Garnier, Francois; Giudici, Pierre-Ange; Greim, Roman; Hebler, Philip; Joram, Christian; Kirn, Thomas; Pierschel, Gerhard; Schateikis, Tobias; Stevens, Holger; Bachlechner, Andreas; Deckenhoff, Mirco; Karpinski, Waclaw; Kruse, Florian; Schultz Von Dratzig, Arndt; Schwering, Georg; Swientek, Krzysztof Piotr; Wlochal, Michael

2015-01-01

The use of scintillating plastic fibres in the SciFi tracker requires rigorous quality control. The fibre diameter and in particular local variations in form of bumps and necks have an impact on the regularity of the winding pattern and hence the spatial resolution. Defects in the fibre cladding lead to light losses and inter-fibre cross talk. Machines have been developed which allow scanning at high throughput of the fibre diameter and the integrity of the cladding. We describe the design principles and implementations of these machines and illustrate their performance. While these machines allow to identify and quantify performance issues of the prototype fibres, they will also play a major role during the series production of the SciFi tracker. If needed, the capacity of the machines allows scanning of the full production volume.

Integrated reconfigurable photonic filters based on interferometric fractional Hilbert transforms.

Science.gov (United States)

Sima, C; Cai, B; Liu, B; Gao, Y; Yu, Y; Gates, J C; Zervas, M N; Smith, P G R; Liu, D

2017-10-01

In this paper, we present integrated reconfigurable photonic filters using fractional Hilbert transformers (FrHTs) and optical phase tuning structure within the silica-on-silicon platform. The proposed structure, including grating-based FrHTs, an X-coupler, and a pair of thermal tuning filaments, is fabricated through the direct UV grating writing technique. The thermal tuning effect is realized by the controllable microheaters located on the two arms of the X-coupler. We investigate the 200 GHz maximum bandwidth photonic FrHTs based on apodized planar Bragg gratings, and analyze the reflection spectrum responses. Through device integration and thermal modulation, the device could operate as photonic notch filters with 5 GHz linewidth and controllable single sideband suppression filters with measured 12 dB suppression ratio. A 50 GHz instantaneous frequency measuring system using this device is also schematically proposed and analyzed with potential 3 dB measurement improvement. The device could be configured with these multiple functions according to need. The reconfigurable structure has great potential in ultrafast all-optical signal processing fields.

Ceftaroline efficacy against high-MIC clinical Staphylococcus aureus isolates in an in vitro hollow-fibre infection model.

Science.gov (United States)

Singh, Renu; Almutairi, Mashal; Alm, Richard A; Lahiri, Sushmita D; San Martin, Maryann; Chen, April; Ambler, Jane E

2017-10-01

The current CLSI and EUCAST clinical susceptible breakpoint for 600 mg q12h dosing of ceftaroline (active metabolite of ceftaroline fosamil) for Staphylococcus aureus is ≤1 mg/L. Efficacy data for S. aureus infections with ceftaroline MIC ≥2 mg/L are limited. This study was designed to generate in-depth pharmacokinetic/pharmacodynamics (PK/PD) understanding of S. aureus isolates inhibited by ≥ 2 mg/L ceftaroline using an in vitro hollow-fibre infection model (HFIM). The PK/PD target of ceftaroline was investigated against 12 diverse characterized clinical MRSA isolates with ceftaroline MICs of 2 or 4 mg/L using q8h dosing for 24 h. These isolates carried substitutions in the penicillin-binding domain (PBD) and/or the non-PBD. Additionally, PD responses of mutants with ceftaroline MICs ranging from 2 to 32 mg/L were evaluated against the mean 600 mg q8h human-simulated dose over 72 h. The mean stasis, 1 log10-kill and 2 log10-kill PK/PD targets were 29%, 32% and 35% f T>MIC, respectively. In addition, these data suggest that the PK/PD target for MRSA is not impacted by the presence of substitutions in the non-PBD commonly found in isolates with ceftaroline MIC values of ≤ 2 mg/L. HFIM studies with 600 mg q8h dosing demonstrated a sustained long-term bacterial suppression for isolates with ceftaroline MICs of 2 and 4 mg/L. Overall, efficacy was demonstrated against a diverse collection of clinical isolates using HFIM indicating the utility of 600 mg ceftaroline fosamil for S. aureus isolates with MIC ≤4 mg/L using q8h dosing. © The Author 2017. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

An XPS round robin investigation on analysis of wood pulp fibres and filter paper

Science.gov (United States)

Johansson, Leena-Sisko; Campbell, J. M.; Fardim, Pedro; Hultén, Anette Heijnesson; Boisvert, Jean-Philippe; Ernstsson, Marie

2005-06-01

X-ray photoelectron spectroscopy (XPS) has been applied to pulp and paper research for decades. However, there has been no attempt to standardise or even systematically compare experimental and analysis procedures, even though it is known that fibrous, nature-derived and insulating fibre materials pose remarkable challenges to reliable surface analysis. The experimental problems are mainly linked with neutralisation, energy resolution, contamination and X-ray induced degradation. We have tested applicability, reliability and reproducibility of XPS analysis on real pulp samples with varying lignin and extractives contents in a small round robin investigation. We also tested the instrumental set-ups with an acetone-extracted filter paper, used as a reference sample. The data, collected at four different laboratories with state-of-the-art instruments indicate that reproducible results can be obtained, despite minor differences in experimental and analysis procedures. However, we found that a specified sample handling procedure and limited X-ray exposure are crucial for reproducible, reliable data. Based on the round robin data we recommend dose restricted monochromatic measurements, a cellulosic in situ reference and a consistent sample handling procedure. The data confirms that a paper-based reference material and the correlation of high-resolution C 1s data with O/C atomic ratios can be used in testing instruments and experimental set-ups for pulp and paper materials.

Analysis of residual stresses in a long hollow cylinder

International Nuclear Information System (INIS)

Tokovyy, Yuriy V.; Ma, Chien-Ching

2011-01-01

This paper presents an analytical method for solving the axisymmetric stress problem for a long hollow cylinder subjected to locally-distributed residual (incompatible) strains. This method is based on direct integration of the equilibrium and compatibility equations, which thereby have been reduced to the set of two governing equations for two key functions with corresponding boundary and integral conditions. The governing equations were solved by making use of the Fourier integral transformation. Application of the method is illustrated with an analysis of the welding residual stresses in a butt-welded thick-walled pipe. - Highlights: → A solution to the axisymmetric stress problem for a hollow cylinder is constructed. → The cylinder is subjected to a field of locally-distributed residual strains. → The method is based on direct integration of the equilibrium equations. → An application of our solution to analysis of welding residual stresses is considered.

A setup to perform X-ray irradiation tests on scintillating fibres for the SciFi project

CERN Document Server

Gavardi, Laura; Joram, Christian; Kristic, Robert

2017-01-01

An X-ray setup has been installed at CERN. The setup will serve for quality assurance purposes related to the acceptance of $11'000~ \\text{km}$ of scintillating plastic fibres for the SciFi detector of LHCb. The X-ray tube has a tungsten target and can be powered up to 60kV, 30mA. The setup is intended to monitor the relative radiation response of the different fibre batches. The dose rate absorbed by the fibre under test can be tuned, adjusting the settings of the X-ray tube and adding aluminium filters of different thicknesses. When operating the X-ray tube without filters at a high voltage of $40\\rm \\,kV$ and an anode current of $30\\rm \\,mA$, the dose rate is about $23\\rm \\,Gy/min$. The maximum dose of about $35\\rm \\,kGy$ expected in the SciFi Tracker can be thus reached in about $1\\rm \\,day$.

Mesoscale cavities in hollow-core waveguides for quantum optics with atomic ensembles

Directory of Open Access Journals (Sweden)

Haapamaki C.M.

2016-08-01

Full Text Available Single-mode hollow-core waveguides loaded with atomic ensembles offer an excellent platform for light–matter interactions and nonlinear optics at low photon levels. We review and discuss possible approaches for incorporating mirrors, cavities, and Bragg gratings into these waveguides without obstructing their hollow cores. With these additional features controlling the light propagation in the hollow-core waveguides, one could potentially achieve optical nonlinearities controllable by single photons in systems with small footprints that can be integrated on a chip. We propose possible applications such as single-photon transistors and superradiant lasers that could be implemented in these enhanced hollow-core waveguides.

Hybrid viscous damper with filtered integral force feedback control

DEFF Research Database (Denmark)

Høgsberg, Jan; Brodersen, Mark L.

2016-01-01

In hybrid damper systems active control devices are usually introduced to enhance the performance of otherwise passive dampers. In the present paper a hybrid damper concept is comprised of a passive viscous damper placed in series with an active actuator and a force sensor. The actuator motion...... is controlled by a filtered integral force feedback strategy, where the main feature is the filter, which is designed to render a damper force that in a phase-plane representation operates in front of the corresponding damper velocity. It is demonstrated that in the specific parameter regime where the damper...

Absolute air filtering equipment in the nuclear industrie. Design - Safety - Experience

International Nuclear Information System (INIS)

Lucas, J.C.

1977-01-01

The problems encountered in the design of absolute filters (HEPA FILTERS) are presented: glass-fibre filter papers; standards and characteristics: efficiency, fire-resistance, humidity-resistance, radiation-resistance, etc; various types of paper folding: deep folds and small folds, dihedrally mounted; filtering elements; designs; characteristics and quality control; The design of filtration equipment is also analysed: mounting in metal or concrete casings. French and American designs (Regulatory Guide 1-52); and gas-tight casings allowing contaminated filters to be renewed without breaking the gas-tight seal

A highly linear fully integrated powerline filter for biopotential acquisition systems.

Science.gov (United States)

Alzaher, Hussain A; Tasadduq, Noman; Mahnashi, Yaqub

2013-10-01

Powerline interference is one of the most dominant problems in detection and processing of biopotential signals. This work presents a new fully integrated notch filter exhibiting high linearity and low power consumption. High filter linearity is preserved utilizing active-RC approach while IC implementation is achieved through replacing passive resistors by R-2R ladders achieving area saving of approximately 120 times. The filter design is optimized for low power operation using an efficient circuit topology and an ultra-low power operational amplifier. Fully differential implementation of the proposed filter shows notch depth of 43 dB (78 dB for 4th-order) with THD of better than -70 dB while consuming about 150 nW from 1.5 V supply.

Cleaning metal filters by pulse-jet

International Nuclear Information System (INIS)

Pickard, P.; Perry, R.A.

1986-01-01

Cleanable metal filters have an established use in the Nuclear Industry. The filters that have been installed in the past have not proved to be sufficiently cleanable. A series of tests were undertaken to study the application of pulse-jet cleaning to metal fibre filter elements. The efficiency of dust removal was examined under various operating conditions. A very high degree of particulate removal was achieved, with a return to almost clean pressure drop. The effectiveness of cleaning was found to vary inversely with blowback pressure. The position of the blowback nozzle with respect to the filter element throat was also found to be important to cleaning efficiency. Under the test conditions the effect of re-entrainment when cleaning on line was found to be minimal. (author)

A bioinspired study on the compressive resistance of helicoidal fibre structures.

Science.gov (United States)

Tan, Ting; Ribbans, Brian

2017-10-01

Helicoidal fibre structures are widely observed in natural materials. In this paper, an integrated experimental and analytical approach was used to investigate the compressive resistance of helicoidal fibre structures. First, helicoidal fibre-reinforced composites were created using three-dimensionally printed helicoids and polymeric matrices, including plain, ring-reinforced and helix-reinforced helicoids. Then, load-displacement curves under monotonic compression tests were collected to measure the compressive strengths of helicoidal fibre composites. Fractographic characterization was performed using an X-ray microtomographer and scanning electron microscope, through which crack propagations in helicoidal structures were illustrated. Finally, mathematical modelling was performed to reveal the essential fibre architectures in the compressive resistance of helicoidal fibre structures. This work reveals that fibre-matrix ratios, helix pitch angles and interlayer rotary angles are critical to the compressive resistance of helicoidal structures.

Wet spinning PAN-fibres from aqueous solutions of ZnCl2 and NaSCN

Science.gov (United States)

Köhler, T.; Peterek, S.; Gries, T.

2017-10-01

In 2007 a chemical regulation order was adopted in Europe and China, to protect the environment and human beings from hazardous substances in consumer goods and their working environment. It is a topic of interest for the rest of the world, as well. Some substances are banned by law from industrial application. The organic solvents Dimethylformamide (DMF) and Dimethylacetamide (DMAc) are candidates for prohibition. To be prepared, the producers of carbon fibres, hollow fibres and wet spun textile products are looking for alternative solvents for their production processes and try to gain according process Know- How. Aqueous solutions of inorganic salts are the most promising alternative. Within this work, the the major differences between the organic and inorganic solvents are shown and the effects on the production costs are shown. This should show the chances which are linked with the use of the alternative solvents.

Damping and tuning of the fibre violin modes in monolithic silica suspensions

International Nuclear Information System (INIS)

Gossler, S; Cagnoli, G; Crooks, D R M; Lueck, H; Rowan, S; Smith, J R; Strain, K A; Hough, J; Danzmann, K

2004-01-01

High Q mirror suspensions are a key element of the advanced interferometric gravitational-wave detectors. In December 2002 the last of the final interferometer optics of GEO 600 were monolithically suspended, using fused silica fibres. The violin modes of the suspension fibres can have Q greater than 10 8 and can therefore interfere with the interferometer length control servo. Hence, the violin modes need to be damped, without degrading the pendulum Q itself. Furthermore, the frequency spread of the fibres used has to be small to allow for high Q notch filtering in the length control servo. The requirements for the violin modes of the two GEO 600 inboard suspensions are Q 6 for the fundamental and Q 6 for the first harmonic mode, respectively. The frequency spread should not exceed 10% within one mode. To accomplish that, two sections of the fibres were coated with amorphous Teflon. By applying the coating, the Q of the relevant modes can be degraded to the desired values and furthermore, the frequencies of these modes can be tuned almost independently with a good accuracy over a wide range. After welding the fibres in the monolithic suspension, a corrective coating was applied to some fibres, to compensate for the frequency spread due to the tension spread of the four fibres within a suspension. We present the method and the results achieved

Phase noise cancellation in polarisation-maintaining fibre links

Science.gov (United States)

Rauf, B.; Vélez López, M. C.; Thoumany, P.; Pizzocaro, M.; Calonico, D.

2018-03-01

The distribution of ultra-narrow linewidth laser radiation is an integral part of many challenging metrological applications. Changes in the optical pathlength induced by environmental disturbances compromise the stability and accuracy of optical fibre networks distributing the laser light and call for active phase noise cancellation. Here we present a laboratory scale optical (at 578 nm) fibre network featuring all polarisation maintaining fibres in a setup with low optical powers available and tracking voltage-controlled oscillators implemented. The stability and accuracy of this system reach performance levels below 1 × 10-19 after 10 000 s of averaging.

Guidance and control of MIR TDL radiation via flexible hollow metallic rectangular pipes and fibers for possible LHS and other optical system compaction and integration

Science.gov (United States)

Yu, C.

1983-01-01

Flexible hollow metallic rectangular pipes and infrared fibers are proposed as alternate media for collection, guidance and manipulation of mid-infrared tunable diode laser (TDL) radiation. Certain features of such media are found to be useful for control of TDL far field patterns, polarization and possibly intensity fluctuations. Such improvement in dimension compatibility may eventually lead to laser heterodyne spectroscopy (LHS) and optical communication system compaction and integration. Infrared optical fiber and the compound parabolic coupling of light into a hollow pipe waveguide are discussed as well as the design of the waveguide.

Properties of hemp fibre polymer composites - An optimisation of fibre properties using novel defibration methods and fibre characterisation

DEFF Research Database (Denmark)

Thygesen, Anders

2006-01-01

Characterization of hemp fibres was carried out with fibres obtained with low handling damage and defibration damage to get an indication of how strong cellulose based fibres that can be produced from hemp. Comparison was made with hemp yarn producedunder traditional conditions where damage...... obtained by steam explosion of hemp fibres prior defibrated with pectin degrading enzymes. The S2 layer in the fibre wall of the hemp fibres consisted of1-4 cellulose rich and lignin poor concentric layers constructed of ca. 100 nm thick lamellae. The microfibril angle showed values in the range 0......-10° for the main part of the S2-layer and 70-90° for the S1-layer. The microfibrils that are mainly parallelwith the fibre axis explain the high fibre stiffness, which in defibrated hemp fibres reached 94 GPa. The defibrated hemp fibres had higher fibre stiffness (88-94 GPa) than hemp yarn (60 GPa), which...

Solar Energy Delivering Greenhouse with an Integrated NIR filter

NARCIS (Netherlands)

Sonneveld, P.J.; Swinkels, G.L.A.M.; Holterman, H.J.; Tuijl, van B.A.J.; Bot, G.P.A.

2008-01-01

The scope of this investigation is the design and development of a new type of greenhouse with an integrated filter for rejecting near infrared radiation (NIR) and a solar energy delivery system. Cooled greenhouses are an important issue to cope with the combination of high global radiation and high

Integration of GPS precise point positioning and MEMS-based INS using unscented particle filter.

Science.gov (United States)

Abd Rabbou, Mahmoud; El-Rabbany, Ahmed

2015-03-25

Integration of Global Positioning System (GPS) and Inertial Navigation System (INS) integrated system involves nonlinear motion state and measurement models. However, the extended Kalman filter (EKF) is commonly used as the estimation filter, which might lead to solution divergence. This is usually encountered during GPS outages, when low-cost micro-electro-mechanical sensors (MEMS) inertial sensors are used. To enhance the navigation system performance, alternatives to the standard EKF should be considered. Particle filtering (PF) is commonly considered as a nonlinear estimation technique to accommodate severe MEMS inertial sensor biases and noise behavior. However, the computation burden of PF limits its use. In this study, an improved version of PF, the unscented particle filter (UPF), is utilized, which combines the unscented Kalman filter (UKF) and PF for the integration of GPS precise point positioning and MEMS-based inertial systems. The proposed filter is examined and compared with traditional estimation filters, namely EKF, UKF and PF. Tightly coupled mechanization is adopted, which is developed in the raw GPS and INS measurement domain. Un-differenced ionosphere-free linear combinations of pseudorange and carrier-phase measurements are used for PPP. The performance of the UPF is analyzed using a real test scenario in downtown Kingston, Ontario. It is shown that the use of UPF reduces the number of samples needed to produce an accurate solution, in comparison with the traditional PF, which in turn reduces the processing time. In addition, UPF enhances the positioning accuracy by up to 15% during GPS outages, in comparison with EKF. However, all filters produce comparable results when the GPS measurement updates are available.

On the determination of crystallinity and cellulose content in plant fibres

DEFF Research Database (Denmark)

Thygesen, Anders; Oddershede, Jette; Lilholt, Hans

2005-01-01

A comparative study of cellulose crystallinity based on the sample crystallinity and the cellulose content in plant fibres was performed for samples of different origin. Strong acid hydrolysis was found superior to agricultural fibre analysis and comprehensive plant fibre analysis for a consistent...... determination of the cellulose content. Crystallinity determinations were based on X-ray powder diffraction methods using side-loaded samples in reflection (Bragg-Brentano) mode. Rietveld refinements based on the recently published crystal structure of cellulose I beta followed by integration of the crystalline...... and 60 - 70 g/ 100 g cellulose in wood based fibres. These findings are significant in relation to strong fibre composites and bio-ethanol production....

Commissioning of the first U.S. hollow fiber condensate filtration system

International Nuclear Information System (INIS)

Wilson, John A.; Mura, Michelle; Garcia, Susan E.; Giannelli, Joseph F.

2008-01-01

Exelon Corporation's Oyster Creek Generating Station, a boiling water reactor (BWR), is the first nuclear plant in the U.S. to install and operate a condensate filtration system using HFF (hollow fiber filter) technology developed in Japan. Oyster Creek is a 640 MW (electric)/1 930 MW (thermal) General Electric BWR-2 (non-jet pump plant) with cascaded heater drains. The plant began commercial operation in 1969, and is one of the two oldest operating commercial BWRs in the U.S. Both noble metal chemical addition (NMCA) and hydrogen injection are used for intergranular stress corrosion cracking (IGSCC) mitigation, and depleted zinc oxide (DZO) is injected for drywell radiation field control. The HFF filters, which were installed in preparation for the operating license renewal, were commissioned in November 2007 and are designed to treat 3 639 m 3 . h -1 (16 020 gallons per minute) using a total filtration surface area of 9 457 m 2 (101 796 ft 2 ). The particle retention rating of the hollow fibers is 0.14 μm, which is considerably smaller than the rating of 1-4 μm for filters commonly used in U.S. condensate filtration applications. System performance and monitoring results during the initial year of operation are reported, including the use of a special hollow fiber health monitoring sampling system. Feedwater and reactor water chemistry control and monitoring strategies and results are discussed, including the effects of the transition from the highest feedwater iron to among the lowest in the U.S. BWR fleet. The projected annual average feedwater iron concentration is -1 . Data on the impact of low iron operation on reactor coolant activated corrosion products and the ratio of 60 Co(soluble)/Zn(soluble), the key parameter used to suppress drywell radiation dose rates, are presented. The zinc control strategy and results are presented, including the effect of low feedwater iron on the reactor water to feedwater zinc concentration factor. The potential need and

Novel concept for producing energy integrating a solar collector with a man made mountain hollow

International Nuclear Information System (INIS)

Zhou Xinping; Yang Jiakuan; Wang Jinbo; Xiao Bo

2009-01-01

The concept of the solar chimney thermal power technology was proven with the successful operation of the Manzanares prototype built in the 1980s. However, all previous attempts at producing energy from a commercial solar chimney thermal power plant on a large scale have failed because of bad engineering and safety. A novel concept for producing energy by integrating a solar collector with a mountain hollow is presented and described. Solar energy is collected in the collector and heats the ground, which is used to store heat energy and heat the indoor air. Then, the hot air is forced by the pressure difference between it and the ambient air to move along the tilted segment and up the vertical segment of the 'chimney', driving the turbine generators to generate electricity. The mountain hollow, formed by excavation in a large-elevation mountain, can avoid the safety issues of erecting a gigantic concrete chimney, which is needed for commercial solar chimney thermal power plants. Furthermore, it can also save a great amount of construction materials for constructing a robust chimney structure and reduce the energy cost to a level less than that of a clean coal power plant, providing a good solution to the reclamation and utilization of undeveloped mountains, especially in mountainous countries

Novel concept for producing energy integrating a solar collector with a man made mountain hollow

Energy Technology Data Exchange (ETDEWEB)

Zhou Xinping [School of Civil Engineering and Mechanics, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei 430074 (China)], E-mail: zhxpmark@hotmail.com; Yang Jiakuan; Wang Jinbo; Xiao Bo [School of Environmental Science and Engineering, Huazhong University of Science and Technology, 1037 Luoyu Road Wuhan, Hubei 430074 (China)

2009-03-15

The concept of the solar chimney thermal power technology was proven with the successful operation of the Manzanares prototype built in the 1980s. However, all previous attempts at producing energy from a commercial solar chimney thermal power plant on a large scale have failed because of bad engineering and safety. A novel concept for producing energy by integrating a solar collector with a mountain hollow is presented and described. Solar energy is collected in the collector and heats the ground, which is used to store heat energy and heat the indoor air. Then, the hot air is forced by the pressure difference between it and the ambient air to move along the tilted segment and up the vertical segment of the 'chimney', driving the turbine generators to generate electricity. The mountain hollow, formed by excavation in a large-elevation mountain, can avoid the safety issues of erecting a gigantic concrete chimney, which is needed for commercial solar chimney thermal power plants. Furthermore, it can also save a great amount of construction materials for constructing a robust chimney structure and reduce the energy cost to a level less than that of a clean coal power plant, providing a good solution to the reclamation and utilization of undeveloped mountains, especially in mountainous countries.

Novel concept for producing energy integrating a solar collector with a man made mountain hollow

Energy Technology Data Exchange (ETDEWEB)

Zhou, Xinping [School of Civil Engineering and Mechanics, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei 430074 (China); Yang, Jiakuan; Wang, Jinbo; Xiao, Bo [School of Environmental Science and Engineering, Huazhong University of Science and Technology, 1037 Luoyu Road Wuhan, Hubei 430074 (China)

2009-03-15

The concept of the solar chimney thermal power technology was proven with the successful operation of the Manzanares prototype built in the 1980s. However, all previous attempts at producing energy from a commercial solar chimney thermal power plant on a large scale have failed because of bad engineering and safety. A novel concept for producing energy by integrating a solar collector with a mountain hollow is presented and described. Solar energy is collected in the collector and heats the ground, which is used to store heat energy and heat the indoor air. Then, the hot air is forced by the pressure difference between it and the ambient air to move along the tilted segment and up the vertical segment of the 'chimney', driving the turbine generators to generate electricity. The mountain hollow, formed by excavation in a large-elevation mountain, can avoid the safety issues of erecting a gigantic concrete chimney, which is needed for commercial solar chimney thermal power plants. Furthermore, it can also save a great amount of construction materials for constructing a robust chimney structure and reduce the energy cost to a level less than that of a clean coal power plant, providing a good solution to the reclamation and utilization of undeveloped mountains, especially in mountainous countries. (author)

Integrable microwave filter based on a photonic crystal delay line.

Science.gov (United States)

Sancho, Juan; Bourderionnet, Jerome; Lloret, Juan; Combrié, Sylvain; Gasulla, Ivana; Xavier, Stephane; Sales, Salvador; Colman, Pierre; Lehoucq, Gaelle; Dolfi, Daniel; Capmany, José; De Rossi, Alfredo

2012-01-01

The availability of a tunable delay line with a chip-size footprint is a crucial step towards the full implementation of integrated microwave photonic signal processors. Achieving a large and tunable group delay on a millimetre-sized chip is not trivial. Slow light concepts are an appropriate solution, if propagation losses are kept acceptable. Here we use a low-loss 1.5 mm-long photonic crystal waveguide to demonstrate both notch and band-pass microwave filters that can be tuned over the 0-50-GHz spectral band. The waveguide is capable of generating a controllable delay with limited signal attenuation (total insertion loss below 10 dB when the delay is below 70 ps) and degradation. Owing to the very small footprint of the delay line, a fully integrated device is feasible, also featuring more complex and elaborate filter functions.

Analyses of integrated aircraft cabin contaminant monitoring network based on Kalman consensus filter.

Science.gov (United States)

Wang, Rui; Li, Yanxiao; Sun, Hui; Chen, Zengqiang

2017-11-01

The modern civil aircrafts use air ventilation pressurized cabins subject to the limited space. In order to monitor multiple contaminants and overcome the hypersensitivity of the single sensor, the paper constructs an output correction integrated sensor configuration using sensors with different measurement theories after comparing to other two different configurations. This proposed configuration works as a node in the contaminant distributed wireless sensor monitoring network. The corresponding measurement error models of integrated sensors are also proposed by using the Kalman consensus filter to estimate states and conduct data fusion in order to regulate the single sensor measurement results. The paper develops the sufficient proof of the Kalman consensus filter stability when considering the system and the observation noises and compares the mean estimation and the mean consensus errors between Kalman consensus filter and local Kalman filter. The numerical example analyses show the effectiveness of the algorithm. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Data assimilation in integrated hydrological modeling using ensemble Kalman filtering

DEFF Research Database (Denmark)

Rasmussen, Jørn; Madsen, H.; Jensen, Karsten Høgh

2015-01-01

Groundwater head and stream discharge is assimilated using the ensemble transform Kalman filter in an integrated hydrological model with the aim of studying the relationship between the filter performance and the ensemble size. In an attempt to reduce the required number of ensemble members...... and estimating parameters requires a much larger ensemble size than just assimilating groundwater head observations. However, the required ensemble size can be greatly reduced with the use of adaptive localization, which by far outperforms distance-based localization. The study is conducted using synthetic data...

Co-extrusion of electrolyte/anode functional layer/anode triple-layer ceramic hollow fibres for micro-tubular solid oxide fuel cells-electrochemical performance study

Science.gov (United States)

Li, Tao; Wu, Zhentao; Li, K.

2015-01-01

In this study, the effects of an anode functional layer (AFL) with controlled thickness on physical and electrochemical properties of a micro-tubular SOFC have been systematically studied. A series of electrolyte/AFL/anode triple-layer hollow fibres with controllable AFL thicknesses (16.9-52.7 μm) have been fabricated via a single-step phase-inversion assisted co-extrusion technique. Both robustness of the cell and gas-tightness of the electrolyte layer are considerably improved by introducing the AFL of this type. The fracture force of the sample with the thickest AFL (9.67 N) almost doubles when compared to the electrolyte/anode dual-layer counterpart (5.24 N). Gas-tightness of the electrolyte layer is also considerably increased as AFL contributes to better-matched sintering behaviours between different components. Moreover, the formation of an AFL simultaneously with electrolyte and anode significantly improves the cell performances. The sample with the thinnest AFL (approximately 16.9 μm, 6% of the total anode thickness) leads to a 30% (from 0.89 to 1.21 W cm-2) increase in maximum power density, due to increased triple-phase boundaries (TPB). However, further increase in TPB from a thicker AFL is less effective for improving the cell performance, due to the substantially increased fuel diffusion resistance and subsequently higher concentration polarization. This indicates that the control over the AFL thickness is critically important in avoiding offsetting the benefits of extended TPB and consequently decreased cell performances.

Maximum Correntropy Unscented Kalman Filter for Ballistic Missile Navigation System based on SINS/CNS Deeply Integrated Mode.

Science.gov (United States)

Hou, Bowen; He, Zhangming; Li, Dong; Zhou, Haiyin; Wang, Jiongqi

2018-05-27

Strap-down inertial navigation system/celestial navigation system ( SINS/CNS) integrated navigation is a high precision navigation technique for ballistic missiles. The traditional navigation method has a divergence in the position error. A deeply integrated mode for SINS/CNS navigation system is proposed to improve the navigation accuracy of ballistic missile. The deeply integrated navigation principle is described and the observability of the navigation system is analyzed. The nonlinearity, as well as the large outliers and the Gaussian mixture noises, often exists during the actual navigation process, leading to the divergence phenomenon of the navigation filter. The new nonlinear Kalman filter on the basis of the maximum correntropy theory and unscented transformation, named the maximum correntropy unscented Kalman filter, is deduced, and the computational complexity is analyzed. The unscented transformation is used for restricting the nonlinearity of the system equation, and the maximum correntropy theory is used to deal with the non-Gaussian noises. Finally, numerical simulation illustrates the superiority of the proposed filter compared with the traditional unscented Kalman filter. The comparison results show that the large outliers and the influence of non-Gaussian noises for SINS/CNS deeply integrated navigation is significantly reduced through the proposed filter.

Dispersion engineering of mode-locked fibre lasers

Science.gov (United States)

Woodward, R. I.

2018-03-01

Mode-locked fibre lasers are important sources of ultrashort pulses, where stable pulse generation is achieved through a balance of periodic amplitude and phase evolutions. A range of distinct cavity pulse dynamics have been revealed, arising from the interplay between dispersion and nonlinearity in addition to dissipative processes such as filtering. This has led to the discovery of numerous novel operating regimes, offering significantly improved laser performance. In this Topical Review, we summarise the main steady-state pulse dynamics reported to date through cavity dispersion engineering, including average solitons, dispersion-managed solitons, dissipative solitons, giant-chirped pulses and similaritons. Characteristic features and the stabilisation mechanism of each regime are described, supported by numerical modelling, in addition to the typical performance and limitations. Opportunities for further pulse energy scaling are discussed, in addition to considering other recent advances including automated self-tuning cavities and fluoride-fibre-based mid-infrared mode-locked lasers.

Fibre tracking

International Nuclear Information System (INIS)

Gaillard, J.M.

1994-03-01

A large-size scintillating plastic fibre tracking detector was built as part of the upgrade of the UA2 central detector at the SPS proton-antiproton collider. The cylindrical fibre detector of average radius of 40 cm consisted of 60000 plastic fibres with an active length of 2.1 m. One of the main motivations was to improve the electron identification. The fibre ends were bunched to be coupled to read-out systems of image intensifier plus CCD, 32 in total. The quality and the reliability of the UA2 fibre detector performance exceeded expectations throughout its years of operation. A few examples of the use of image intensifiers and of scintillating fibres in biological instrumentation are described. (R.P.) 11 refs., 15 figs., 2 tabs

Hollow-in-Hollow Carbon Spheres for Lithium-ion Batteries with Superior Capacity and Cyclic Performance

International Nuclear Information System (INIS)

Zang, Jun; Ye, Jianchuan; Fang, Xiaoliang; Zhang, Xiangwu; Zheng, Mingsen; Dong, Quanfeng

2015-01-01

Highlights: • Hollow-in-hollow structured HIHCS was synthesized via a facile templating strategy. • The HCS core and hollow carbon shell constitute the hollow-in-hollow structure. • The HIHCS exhibited superior rate capability and cycle stability as anode material. • The excellent performance is attributed to the unique hollow-in-hollow structure. - Abstract: Hollow spheres structured materials have been intensively pursued due to their unique properties for energy storage. In this paper, hollow-in-hollow carbon spheres (HIHCS) with a multi-shelled structure were successfully synthesized using a facile hard-templating procedure. When evaluated as anode material for lithium-ion batteries, the resultant HIHCS anode exhibited superior capacity and cycling stability than HCS. It could deliver reversible capacities of 937, 481, 401, 304 and 236 mAh g −1 at current densities of 0.1 A g −1 , 1 A g −1 , 2 A g −1 , 5 A g −1 and 10 A g −1 , respectively. And capacity fading is not apparent in 500 cycles at 5 A g −1 . The excellent performance of the HIHCS anode is ascribed to its unique hollow-in-hollow structure and high specific surface area.

All-fibre source of amplitude squeezed light pulses

Energy Technology Data Exchange (ETDEWEB)

Meissner, Markus; Marquardt, Christoph; Heersink, Joel; Gaber, Tobias; Wietfeld, Andre; Leuchs, Gerd; Andersen, Ulrik L [Institut fuer Optik, Information und Photonik, Max-Planck Forschungsgruppe Universitaet Erlangen-Nuernberg, Staudtstrasse 7/B2, 91058, Erlangen (Germany)

2004-08-01

An all-fibre source of amplitude squeezed solitons utilizing the self-phase modulation in an asymmetric Sagnac interferometer is experimentally demonstrated. The asymmetry of the interferometer is passively controlled by an integrated fibre coupler, allowing for the optimization of the noise reduction. We have carefully studied the dependence of the amplitude noise on the asymmetry and the power launched into the Sagnac interferometer. Qualitatively, we find good agreement between the experimental results, a semi-classical theory and earlier numerical calculations (Schmitt et al 1998 Phys. Rev. Lett. 81 2446). The stability and flexibility of this all-fibre source makes it particularly well suited to applications in quantum information science.

Production and cross-sectional characterization of aligned co-electrospun hollow microfibrous bulk assemblies

Energy Technology Data Exchange (ETDEWEB)

Zhou, Feng-Lei [Centre for Imaging Sciences, The University of Manchester, Manchester M13 9PT (United Kingdom); The School of Materials, The University of Manchester, Manchester M13 9PL (United Kingdom); CRUK-EPSRC Cancer Imaging Centre in Cambridge and Manchester (United Kingdom); Parker, Geoff J.M., E-mail: geoff.parker@manchester.ac.uk [Centre for Imaging Sciences, The University of Manchester, Manchester M13 9PT (United Kingdom); CRUK-EPSRC Cancer Imaging Centre in Cambridge and Manchester (United Kingdom); Eichhorn, Stephen J. [College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter EX4 4QF (United Kingdom); Hubbard Cristinacce, Penny L. [Centre for Imaging Sciences, The University of Manchester, Manchester M13 9PT (United Kingdom); School of Psychological Sciences, University of Manchester, Manchester M13 9PT (United Kingdom)

2015-11-15

The development of co-electrospun (co-ES) hollow microfibrous assemblies of an appreciable thickness is critical for many practical applications, including filtration membranes and tissue-mimicking scaffolds. In this study, thick uniaxially aligned hollow microfibrous assemblies forming fiber bundles and strips were prepared by co-ES of polycaprolactone (PCL) and polyethylene oxide (PEO) as shell and core materials, respectively. Hollow microfiber bundles were deposited on a fixed rotating disc, which resulted in non-controllable cross-sectional shapes on a macroscopic scale. In comparison, fiber strips were produced with tuneable thickness and width by additionally employing an x–y translation stage in co-ES. Scanning electron microscopy (SEM) images of cross-sections of fiber assemblies were analyzed to investigate the effects of production time (from 0.5 h to 12 h), core flow rate (from 0.8 mL/h to 2.0 mL/h) and/or translation speed (from 0.2 mm/s to 5 mm/s) on the pores and porosity. We observed significant changes in pore size and shape with core flow rate but the influence of production time varied; five strips produced under the same conditions had reasonably good size and porosity reproducibility; pore sizes didn't vary significantly from strip bottom to surface, although the porosity gradually decreased and then returned to the initial level. - Highlights: • Hollow microfibrous assemblies based on co-electrospinning are demonstrated. • The thickness and width of co-electrospun strips were controllable. • Cross-sections of fibres had non-normally distributed pore sizes and shapes. • Cross-sections were significantly influenced by production time and flow rate. • Co-electrospun strips had reasonably good reproducible cross-sections.

Removal of toxic industrial chemicals using novel adsorbent hollow fibres

OpenAIRE

Jeffs, Corinne

2015-01-01

The current military respirator provides protection from contaminants using a cartridge packed with adsorbent activated carbon particles treated with metal salts to provide protection from toxic gases. However, the user of this respirator is subject to a physiological burden as a result. One component of this burden is the pressure drop, which makes breathing through the respirator filter difficult, with the burden becoming more severe at higher breathing rates. This project investigates the ...

Damping and tuning of the fibre violin modes in monolithic silica suspensions

Energy Technology Data Exchange (ETDEWEB)

Gossler, S [Max-Planck-Institute for Gravitational Physics (Albert-Einstein-Institute) and University of Hannover, Callinstr 38, D-30167 Hannover (Germany); Cagnoli, G [Department of Physics and Astronomy, Institute for Gravitational Research, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Crooks, D R M [Department of Physics and Astronomy, Institute for Gravitational Research, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Lueck, H [Max-Planck-Institute for Gravitational Physics (Albert-Einstein-Institute) and University of Hannover, Callinstr 38, D-30167 Hannover (Germany); Rowan, S [Department of Physics and Astronomy, Institute for Gravitational Research, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Smith, J R [Max-Planck-Institute for Gravitational Physics (Albert-Einstein-Institute) and University of Hannover, Callinstr 38, D-30167 Hannover (Germany); Strain, K A [Department of Physics and Astronomy, Institute for Gravitational Research, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Hough, J [Department of Physics and Astronomy, Institute for Gravitational Research, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Danzmann, K [Max-Planck-Institute for Gravitational Physics (Albert-Einstein-Institute) and University of Hannover, Callinstr 38, D-30167 Hannover (Germany)

2004-03-07

High Q mirror suspensions are a key element of the advanced interferometric gravitational-wave detectors. In December 2002 the last of the final interferometer optics of GEO 600 were monolithically suspended, using fused silica fibres. The violin modes of the suspension fibres can have Q greater than 10{sup 8} and can therefore interfere with the interferometer length control servo. Hence, the violin modes need to be damped, without degrading the pendulum Q itself. Furthermore, the frequency spread of the fibres used has to be small to allow for high Q notch filtering in the length control servo. The requirements for the violin modes of the two GEO 600 inboard suspensions are Q < 3 x 10{sup 6} for the fundamental and Q < 2 x 10{sup 6} for the first harmonic mode, respectively. The frequency spread should not exceed 10% within one mode. To accomplish that, two sections of the fibres were coated with amorphous Teflon. By applying the coating, the Q of the relevant modes can be degraded to the desired values and furthermore, the frequencies of these modes can be tuned almost independently with a good accuracy over a wide range. After welding the fibres in the monolithic suspension, a corrective coating was applied to some fibres, to compensate for the frequency spread due to the tension spread of the four fibres within a suspension. We present the method and the results achieved.

Hollow fibre liquid phase micro-extraction by facilitated anionic exchange for the determination of flavonoids in faba beans (Vicia faba L.).

Science.gov (United States)

Chaieb, Nadia; López-Mesas, Montserrat; Luis González, Johannes; Mars, Messaoud; Valiente, Manuel

2015-01-01

Flavonoids are polyphenolic compounds found ubiquitously in foods of plant origin. They are commonly extracted from plant materials with ethanol, methanol, water, their combination or even with acidified extracting solutions. The disadvantages of these methods are the use of high quantity of organic solvent, the possible loss of analytes in the different steps and the laborious process of the techniques. In addition, the complexity of the phenolic mixtures present in plant materials requires a preliminary clean-up and fractionation of the crude extracts. To develop a hollow fibre liquid phase micro-extraction (HF-LPME) method for a one step clean-up and pre-concentration of flavonoids. Two flavonoids (catechin and rutin) has been extracted by HF-LPME and analysed by HPLC. The related driving force for the liquid membrane has been studied by means of facilitated and non-facilitated transport. Different ionic and non-ionic water insoluble compounds [trioctylamine (TOA), tributyl phosphate (TBP), trioctylphosphine oxide (TOPO) and methyltrioctylammonium chloride (aliquat 336)] were used as carriers. The liquid membrane was constituted by a solution of n-decanol in the presence or absence of carriers. Maximum enrichment factors were obtained with n-decanol/aliquat 336 (20%) as organic liquid membrane, sodium hydroxide (NaOH) (0.1 M) as donor solution, sodium chloride (NaCl) (2 M) as acceptor solution and 3 h as extraction time. Under these conditions, good results for validation parameters were obtained [for linearity, limit of detection (LOD), limit of quantitation (LOQ) and repeatability]. The developed method is simple, effective and has been successfully applied to determine catechin and rutin in ethanolic extracts of faba beans. Copyright © 2015 John Wiley & Sons, Ltd.

Nb{sub 2}O{sub 5} hollow nanospheres as anode material for enhanced performance in lithium ion batteries

Energy Technology Data Exchange (ETDEWEB)

Sasidharan, Manickam [Department of Chemistry, Faculty of Science and Engineering, Saga University, 1 Honjo-machi, Saga 840-8502 (Japan); Gunawardhana, Nanda [Advanced Research Center, Saga University, 1341 Yoga-machi, Saga 840-0047 (Japan); Yoshio, Masaki, E-mail: yoshio@cc.saga-u.ac.jp [Advanced Research Center, Saga University, 1341 Yoga-machi, Saga 840-0047 (Japan); Nakashima, Kenichi, E-mail: nakashik@cc.saga-u.ac.jp [Department of Chemistry, Faculty of Science and Engineering, Saga University, 1 Honjo-machi, Saga 840-8502 (Japan)

2012-09-15

Graphical abstract: Nb{sub 2}O{sub 5} hollow nanosphere constructed electrode delivers high capacity of 172 mAh g{sup −1} after 250 cycles and maintains structural integrity and excellent cycling stability. Highlights: ► Nb{sub 2}O{sub 5} hollow nanospheres synthesis was synthesized by soft-template. ► Nb{sub 2}O{sub 5} hollow nanospheres were investigated as anode material in Li-ion battery. ► Nanostructured electrode delivers high capacity of 172 mAh g{sup −1} after 250 cycles. ► The electrode maintains the structural integrity and excellent cycling stability. ► Nanosized shell domain facilitates fast lithium intercalation/deintercalation. -- Abstract: Nb{sub 2}O{sub 5} hollow nanospheres of average diameter ca. ∼29 nm and hollow cavity size ca. 17 nm were synthesized using polymeric micelles with core–shell–corona architecture under mild conditions. The hollow particles were thoroughly characterized by transmission electron microscope (TEM), X-ray diffraction (XRD), infrared spectroscopy (FTIR), thermal (TG/DTA) and nitrogen adsorption analyses. Thus obtained Nb{sub 2}O{sub 5} hollow nanospheres were investigated as anode materials for lithium ion rechargeable batteries for the first time. The nanostructured electrode delivers high capacity of 172 mAh g{sup −1} after 250 cycles of charge/discharge at a rate of 0.5 C. More importantly, the hollow particles based electrodes maintains the structural integrity and excellent cycling stability even after exposing to high current density 6.25 A g{sup −1}. The enhanced electrochemical behavior is ascribed to hollow cavity coupled with nanosized Nb{sub 2}O{sub 5} shell domain that facilitates fast lithium intercalation/deintercalation kinetics.

Filtering and concentrating device for processing radioactive waste and operation method therefor, processing facility for radioactive wastes and processing method therefor

International Nuclear Information System (INIS)

Serizawa, Ken-ichi; Yamazaki, Masami

1998-01-01

A filtering and concentrating device is prepared by assembling a porous ceramic filtering material having a pore diameter of 1 μm or less secured by a support to a filtering device main body. The porous ceramic filtering material preferably comprises a surface portion having pores having a diameter of 1 μm or less and a hollow ceramic material having filtering flow channels having a diameter greater than the pores on the surface portion. The ratio of the diameter and the thickness of the hollow ceramic material is determined to greater than 50 : 1. The filtering and concentrating device precisely filter and concentrate radioactive liquid wastes containing an insoluble solid content generated from a nuclear power plant to conduct solid/liquid separation thereby forming a filtrate and concentrated wastes having a mass concentration of 20% or more. With such a constitution, stable filtration and concentration can be conducted while reducing occurrence of clogging of filtering materials. In addition, the frequency for the exchange of filtering materials can be reduced. (I.N.)

The Influence of Fibre Content on the Performance of Steel Fibre ...

African Journals Online (AJOL)

The Influence of Fibre Content on the Performance of Steel Fibre Refractory Concrete. ... Little information is available on the effect of fibre content on refractory performance and in particular resistance to thermal shock. This study has examined the influence of fibre content of stainless steel melt extract fibres on the ...

Influence of air pressure on soliton formation in hollow-core photonic bandgap fibers

DEFF Research Database (Denmark)

Lægsgaard, Jesper; Roberts, Peter John

2009-01-01

Abstract Soliton formation during dispersive compression of chirped few-picosecond pulses at the microjoule level in a hollow-core photonic bandgap (HC-PBG) fiber is studied by numerical simulations. Long-pass filtering of the emerging frequency-shifted solitons is investigated with the objective...... of obtaining pedestal-free output pulses. Particular emphasis is placed on the influence of the air pressure in the HC-PBG fiber. It is found that a reduction in air pressure enables an increase in the fraction of power going into the most redshifted soliton and also improves the quality of the filtered pulse...

Oxidation of lignin in hemp fibres by laccase: effects on mechanical properties of hemp fibres and unidirectional fibre/epoxy composites

DEFF Research Database (Denmark)

Liu, Ming; Baum, Andreas; Odermatt, Jürgen

2017-01-01

Laccase activity catalyzes oxidation and polymerization of phenols. The effect of laccase treatment on the mechanical properties of hemp fibres and hemp fibre/epoxy composites was examined. Laccase treatment on top of 0.5% EDTA + 0.2% endo-polygalacturonase (EPG) treatments increased the mechanical...... properties of hemp fibres and fibre/epoxy composites. Comparing all fibre treatments, composites with 0.5% EDTA + 0.2% EPG + 0.5% laccase treated fibres had highest stiffness of 42 GPa and highest ultimate tensile strength (UTS) of 326 MPa at a fibre volume content of 50%. The thermal resistance of hemp...... hemp fibres and their composites were due to laccase catalyzed polymerization of lignin moieties in hemp fibres....

Fibre Length Reduction in Natural Fibre-Reinforced Polymers during Compounding and Injection Moulding—Experiments Versus Numerical Prediction of Fibre Breakage

Directory of Open Access Journals (Sweden)

Katharina Albrecht

2018-03-01

Full Text Available To establish injection-moulded, natural fibre-reinforced polymers in the automotive industry, numerical simulations are important. To include the breakage behaviour of natural fibres in simulations, a profound understanding is necessary. In this study, the length and width reduction of flax and sisal fibre bundles were analysed experimentally during compounding and injection moulding. Further an optical analysis of the fibre breakage behaviour was performed via scanning electron microscopy and during fibre tensile testing with an ultra-high-speed camera. The fibre breakage of flax and sisal during injection moulding was modelled using a micromechanical model. The experimental and simulative results consistently show that during injection moulding the fibre length is not reduced further; the fibre length was already significantly reduced during compounding. For the mechanical properties of a fibre-reinforced composite it is important to overachieve the critical fibre length in the injection moulded component. The micromechanical model could be used to predict the necessary fibre length in the granules.

A validation of the fibre orientation and fibre length attrition prediction for long fibre-reinforced thermoplastics

Science.gov (United States)

Hopmann, Ch.; Weber, M.; van Haag, J.; Schöngart, M.

2015-05-01

To improve the mechanical performance of polymeric parts, fibre reinforcement has established in industrial applications during the last decades. Next to the widely used Short Fibre-reinforced Thermoplastics (SFT) the use of Long Fibre-reinforced Thermoplastics (LFT) is increasingly growing. Especially for non-polar polymeric matrices like polypropylene (PP), longer fibres can significantly improve the mechanical performance. As with every kind of discontinuous fibre reinforcement the fibre orientations (FO) show a high impact on the mechanical properties. On the contrary to SFT where the local fibre length distribution (FLD) can be often neglected, for LFT the FLD show a high impact on the material's properties and has to be taken into account in equal measure to the FOD. Recently numerical models are available in commercial filling simulation software and allow predicting both the local FOD and FLD in LFT parts. The aim of this paper is to compare i.) the FOD results and ii) the FLD results from available orientation- and fibre length attrition-models to those obtained from experimental data. The investigations are conducted by the use of different injection moulded specimens made from long glass fibre reinforced PP. In order to determine the FOD, selected part sections are examined by means of Computed Tomographic (CT) analyses. The fully three dimensional measurement of the FOD is then performed by digital image processing using grey scale correlation. The FLD results are also obtained by using digital image processing after a thermal pyrolytic separation of the polymeric matrix from the fibres. Further the FOD and the FLD are predicted by using a reduced strain closure (RSC) as well as an anisotropic rotary diffusion - reduced strain closure model (ARD-RSC) and Phelps-Tucker fibre length attrition model implemented in the commercial filling software Moldflow, Autodesk Inc., San Rafael, CA, USA.

A validation of the fibre orientation and fibre length attrition prediction for long fibre-reinforced thermoplastics

International Nuclear Information System (INIS)

Hopmann, Ch.; Weber, M.; Haag, J. van; Schöngart, M.

2015-01-01

To improve the mechanical performance of polymeric parts, fibre reinforcement has established in industrial applications during the last decades. Next to the widely used Short Fibre-reinforced Thermoplastics (SFT) the use of Long Fibre-reinforced Thermoplastics (LFT) is increasingly growing. Especially for non-polar polymeric matrices like polypropylene (PP), longer fibres can significantly improve the mechanical performance. As with every kind of discontinuous fibre reinforcement the fibre orientations (FO) show a high impact on the mechanical properties. On the contrary to SFT where the local fibre length distribution (FLD) can be often neglected, for LFT the FLD show a high impact on the material’s properties and has to be taken into account in equal measure to the FOD. Recently numerical models are available in commercial filling simulation software and allow predicting both the local FOD and FLD in LFT parts. The aim of this paper is to compare i.) the FOD results and ii) the FLD results from available orientation- and fibre length attrition-models to those obtained from experimental data. The investigations are conducted by the use of different injection moulded specimens made from long glass fibre reinforced PP. In order to determine the FOD, selected part sections are examined by means of Computed Tomographic (CT) analyses. The fully three dimensional measurement of the FOD is then performed by digital image processing using grey scale correlation. The FLD results are also obtained by using digital image processing after a thermal pyrolytic separation of the polymeric matrix from the fibres. Further the FOD and the FLD are predicted by using a reduced strain closure (RSC) as well as an anisotropic rotary diffusion - reduced strain closure model (ARD-RSC) and Phelps-Tucker fibre length attrition model implemented in the commercial filling software Moldflow, Autodesk Inc., San Rafael, CA, USA

A validation of the fibre orientation and fibre length attrition prediction for long fibre-reinforced thermoplastics

Energy Technology Data Exchange (ETDEWEB)

Hopmann, Ch.; Weber, M.; Haag, J. van; Schöngart, M. [Institute of Plastics Processing (IKV) at RWTH Aachen University, Pontstr. 49, 52062 Aachen (Germany)

2015-05-22

To improve the mechanical performance of polymeric parts, fibre reinforcement has established in industrial applications during the last decades. Next to the widely used Short Fibre-reinforced Thermoplastics (SFT) the use of Long Fibre-reinforced Thermoplastics (LFT) is increasingly growing. Especially for non-polar polymeric matrices like polypropylene (PP), longer fibres can significantly improve the mechanical performance. As with every kind of discontinuous fibre reinforcement the fibre orientations (FO) show a high impact on the mechanical properties. On the contrary to SFT where the local fibre length distribution (FLD) can be often neglected, for LFT the FLD show a high impact on the material’s properties and has to be taken into account in equal measure to the FOD. Recently numerical models are available in commercial filling simulation software and allow predicting both the local FOD and FLD in LFT parts. The aim of this paper is to compare i.) the FOD results and ii) the FLD results from available orientation- and fibre length attrition-models to those obtained from experimental data. The investigations are conducted by the use of different injection moulded specimens made from long glass fibre reinforced PP. In order to determine the FOD, selected part sections are examined by means of Computed Tomographic (CT) analyses. The fully three dimensional measurement of the FOD is then performed by digital image processing using grey scale correlation. The FLD results are also obtained by using digital image processing after a thermal pyrolytic separation of the polymeric matrix from the fibres. Further the FOD and the FLD are predicted by using a reduced strain closure (RSC) as well as an anisotropic rotary diffusion - reduced strain closure model (ARD-RSC) and Phelps-Tucker fibre length attrition model implemented in the commercial filling software Moldflow, Autodesk Inc., San Rafael, CA, USA.

Maximum Correntropy Unscented Kalman Filter for Ballistic Missile Navigation System based on SINS/CNS Deeply Integrated Mode

Directory of Open Access Journals (Sweden)

Bowen Hou

2018-05-01

Full Text Available Strap-down inertial navigation system/celestial navigation system ( SINS/CNS integrated navigation is a high precision navigation technique for ballistic missiles. The traditional navigation method has a divergence in the position error. A deeply integrated mode for SINS/CNS navigation system is proposed to improve the navigation accuracy of ballistic missile. The deeply integrated navigation principle is described and the observability of the navigation system is analyzed. The nonlinearity, as well as the large outliers and the Gaussian mixture noises, often exists during the actual navigation process, leading to the divergence phenomenon of the navigation filter. The new nonlinear Kalman filter on the basis of the maximum correntropy theory and unscented transformation, named the maximum correntropy unscented Kalman filter, is deduced, and the computational complexity is analyzed. The unscented transformation is used for restricting the nonlinearity of the system equation, and the maximum correntropy theory is used to deal with the non-Gaussian noises. Finally, numerical simulation illustrates the superiority of the proposed filter compared with the traditional unscented Kalman filter. The comparison results show that the large outliers and the influence of non-Gaussian noises for SINS/CNS deeply integrated navigation is significantly reduced through the proposed filter.

Hollow laser plasma self-confined microjet generation

Science.gov (United States)

Sizyuk, Valeryi; Hassanein, Ahmed; CenterMaterials under Extreme Environment Team

2017-10-01

Hollow laser beam produced plasma (LPP) devices are being used for the generation of the self-confined cumulative microjet. Most important place by this LPP device construction is achieving of an annular distribution of the laser beam intensity by spot. An integrated model is being developed to detailed simulation of the plasma generation and evolution inside the laser beam channel. The model describes in two temperature approximation hydrodynamic processes in plasma, laser absorption processes, heat conduction, and radiation energy transport. The total variation diminishing scheme in the Lax-Friedrich formulation for the description of plasma hydrodynamic is used. Laser absorption and radiation transport models on the base of Monte Carlo method are being developed. Heat conduction part on the implicit scheme with sparse matrixes using is realized. The developed models are being integrated into HEIGHTS-LPP computer simulation package. The integrated modeling of the hollow beam laser plasma generation showed the self-confinement and acceleration of the plasma microjet inside the laser channel. It was found dependence of the microjet parameters including radiation emission on the hole and beam radiuses ratio. This work is supported by the National Science Foundation, PIRE project.

Switching a Nanocluster Core from Hollow to Non-hollow

KAUST Repository

Bootharaju, Megalamane Siddaramappa

2016-03-24

Modulating the structure-property relationship in atomically precise nanoclusters (NCs) is vital for developing novel NC materials and advancing their applications. While promising biphasic ligand-exchange (LE) strategies have been developed primarily to attain novel NCs, understanding the mechanistic aspects involved in tuning the core and the ligand-shell of NCs in such biphasic processes is challenging. Here, we design a single phase LE process that enabled us to elucidate the mechanism of how a hollow NC (e.g., [Ag44(SR)30]4-, -SR: thiolate) converts into a non-hollow NC (e.g., [Ag25(SR)18]-), and vice versa. Our study reveals that the complete LE of the hollow [Ag44(SPhF)30]4- NCs (–SPhF: 4-fluorobenzenethiolate) with incoming 2,4-dimethylbenzenethiol (HSPhMe2) induced distortions in the Ag44 structure forming the non-hollow [Ag25(SPhMe2)18]- by a disproportionation mechanism. While the reverse reaction of [Ag25(SPhMe2)18]- with HSPhF prompted an unusual dimerization of Ag25, followed by a rearrangement step that reproduces the original [Ag44(SPhF)30]4-. Remarkably, both the forward and the backward reactions proceed through similar size intermediates that seem to be governed by the boundary conditions set by the thermodynamic and electronic stability of the hollow and non-hollow metal cores. Furthermore, the resizing of NCs highlights the surprisingly long-range effect of the ligands which are felt by atoms far deep in the metal core, thus opening a new path for controlling the structural evolution of nanoparticles.

X-ray differential phase-contrast tomographic reconstruction with a phase line integral retrieval filter

International Nuclear Information System (INIS)

Fu, Jian; Hu, Xinhua; Li, Chen

2015-01-01

We report an alternative reconstruction technique for x-ray differential phase-contrast computed tomography (DPC-CT). This approach is based on a new phase line integral projection retrieval filter, which is rooted in the derivative property of the Fourier transform and counteracts the differential nature of the DPC-CT projections. It first retrieves the phase line integral from the DPC-CT projections. Then the standard filtered back-projection (FBP) algorithms popular in x-ray absorption-contrast CT are directly applied to the retrieved phase line integrals to reconstruct the DPC-CT images. Compared with the conventional DPC-CT reconstruction algorithms, the proposed method removes the Hilbert imaginary filter and allows for the direct use of absorption-contrast FBP algorithms. Consequently, FBP-oriented image processing techniques and reconstruction acceleration softwares that have already been successfully used in absorption-contrast CT can be directly adopted to improve the DPC-CT image quality and speed up the reconstruction

Development of Hollow Cathode of High Power Middle Pressure Arcjet

National Research Council Canada - National Science Library

Vaulin, Eujeni

1995-01-01

...: Determine integral performances of arcjet devices in nitrogen, ammonia, and their mixtures using hollow cathode devices at low and high current levels, perform short term tests (up to 50 hours...

Acquiring beam data for a flattening-filter free linear accelerator using organic scintillators

International Nuclear Information System (INIS)

Beierholm, A.R.; Behrens, C.F.; Hoffmann, L.; Andersen, C.E.

2013-01-01

Fibre-coupled organic scintillators have been proven a credible alternative to clinically implemented methods for radiotherapy dosimetry, primarily due to their water equivalence and good spatial resolution. Furthermore, the fast response of the scintillators can be exploited to perform time-resolved dosimetry on a highly detailed level. In this study, we present beam data for a Varian TrueBeam linear accelerator, which is capable of delivering flattening-filter free (FFF 1 ) clinical X-ray beams. The beam data have been acquired using an in-house developed dosimetry system based on fibre-coupled organic scintillators. The presented data exhibit high accuracy and precision when compared with data obtained using commercial dosimetry methods, and agree well with results published in the literature. -- Highlights: •A dosimetry system based on fibre-coupled organic scintillators is presented. •The system is used for radiotherapy beams with and without flattening filter. •Measurements show good agreement with various commercial dosimeters

INFLUENCE OF KENAF AND POLYPROPYLENE FIBRES ON MECHANICAL AND DURABILITY PROPERTIES OF FIBRE REINFORCED LIGHTWEIGHT FOAMED CONCRETE

Directory of Open Access Journals (Sweden)

H. AWANG

2015-04-01

Full Text Available This paper investigates the mechanical and durability properties of lightweight foamed concrete (LFC with the inclusion of kenaf and polypropylene fibres. A density of 1000kg/m3 foamed concrete was used for all the tested specimens. The ratio of cement, sand and water used was 1:1.5:0.45. Polypropylene and kenaf fibres were used as additives at 0.25% and 0.4% by volume of the total mix. A 30% cement replacement by fly ash was used with each type of additive. All the experiments were set up in accordance with International standard methods of testing. Scanning electron microscopy (SEM analysis is included to have a better view of the concrete behavior with fibre inclusions. In reference to the analysis and discussion, the types of fibre used were proven to have a lesser contribution towards compressive strength or might even have reduced the result. However, the integration of fly ash enhanced the compressive strength. In addition, a higher percentage of fiber inclusions had been recorded to have a positive contribution towards flexural, tensile spiltting and shrinkage properties of LFC.

Shrinkage Behaviour of Fibre Reinforced Concrete with Recycled Tyre Polymer Fibres

Directory of Open Access Journals (Sweden)

Marijana Serdar

2015-01-01

Full Text Available Different types of fibres are often used in concrete to prevent microcracking due to shrinkage, and polypropylene fibres are among the most often used ones. If not prevented, microcracks can lead to the development of larger cracks as drying shrinkage occurs, enabling penetration of aggressive substances from the environment and reducing durability of concrete structures. The hypothesis of the present research is that polypropylene fibres, used in concrete for controlling formation of microcracks due to shrinkage, can be replaced with recycled polymer fibres obtained from end-of-life tyres. To test the hypothesis, concrete mixtures containing polypropylene fibres and recycled tyre polymer fibres were prepared and tested. Experimental programme focused on autogenous, free, and restrained shrinkage. It was shown that PP fibres can be substituted with higher amount of recycled tyre polymer fibres obtaining concrete with similar shrinkage behaviour. The results indicate promising possibilities of using recycled tyre polymer fibres in concrete products. At the same time, such applications would contribute to solving the problem of waste tyre disposal.

Hollow Microtube Resonators via Silicon Self-Assembly toward Subattogram Mass Sensing Applications.

Science.gov (United States)

Kim, Joohyun; Song, Jungki; Kim, Kwangseok; Kim, Seokbeom; Song, Jihwan; Kim, Namsu; Khan, M Faheem; Zhang, Linan; Sader, John E; Park, Keunhan; Kim, Dongchoul; Thundat, Thomas; Lee, Jungchul

2016-03-09

Fluidic resonators with integrated microchannels (hollow resonators) are attractive for mass, density, and volume measurements of single micro/nanoparticles and cells, yet their widespread use is limited by the complexity of their fabrication. Here we report a simple and cost-effective approach for fabricating hollow microtube resonators. A prestructured silicon wafer is annealed at high temperature under a controlled atmosphere to form self-assembled buried cavities. The interiors of these cavities are oxidized to produce thin oxide tubes, following which the surrounding silicon material is selectively etched away to suspend the oxide tubes. This simple three-step process easily produces hollow microtube resonators. We report another innovation in the capping glass wafer where we integrate fluidic access channels and getter materials along with residual gas suction channels. Combined together, only five photolithographic steps and one bonding step are required to fabricate vacuum-packaged hollow microtube resonators that exhibit quality factors as high as ∼ 13,000. We take one step further to explore additionally attractive features including the ability to tune the device responsivity, changing the resonator material, and scaling down the resonator size. The resonator wall thickness of ∼ 120 nm and the channel hydraulic diameter of ∼ 60 nm are demonstrated solely by conventional microfabrication approaches. The unique characteristics of this new fabrication process facilitate the widespread use of hollow microtube resonators, their translation between diverse research fields, and the production of commercially viable devices.

Re-Investigation of Generalized Integrator Based Filters From a First-Order-System Perspective

DEFF Research Database (Denmark)

Xin, Zhen; Zhao, Rende; Mattavelli, Paolo

2016-01-01

The generalized integrator (GI)-based filters can be categorized into two types: one is related to quadrature signal generator (QSG), and the other is related to sequence filter (SF). The QSG is used for generating the in-quadrature sinusoidal signals and the SF works for extracting the symmetrical...... extended structures and thus restrict their applications. To overcome the drawback, this paper uses the first-order-system concept to re-investigate the GI-based filters, with which their working principles can be intuitively understood and their structure correlations can be easily discovered. Moreover...

Stress concentrations in an impregnated fibre bundle with random fibre packing

OpenAIRE

Swolfs, Y.; Gorbatikh, L.; Romanov, V.; Orlova, S.; Lomov, S. V.; Verpoest, I.

2013-01-01

The stress redistribution after a single fibre break is a fundamental issue in longitudinal strength models for unidirectional composites. Current models assume hexagonal or square fibre packings. In the present work, random fibre packings were modelled using 3D finite element analysis and compared to ordered fibre packings. Significant differences in the stress redistribution are found. Compared to square and hexagonal packings, random fibre packings result in smaller stress concentration fa...

Blast Resistance of Slurry Infiltrated Fibre Concrete with Waste Steel Fibres from Tires

Directory of Open Access Journals (Sweden)

Drdlová Martina

2018-01-01

Full Text Available The utilization of waste steel fibres (coming from the recycling process of the old tires in production of blast resistant cement based panels was assessed. Waste fibres were incorporated in slurry infiltrated fibre concrete (SIFCON, which is a special type of ultra-highperformance fibre reinforced concrete with high fibre content. The technological feasibility (i.e. suitability of the waste fibres for SIFCON technology was assessed using homogeneity test. Test specimens were prepared with three volume fractions (5; 7.5 and 10 % by vol. of waste unclassified fibres. SIFCON with industrial steel fibres (10% by vol. and ultra-highperformance fibre concrete with industrial fibres were also cast and tested for comparison purposes. Quasi-static mechanical properties were determined. Real blast tests were performed on the slab specimens (500x500x40 mm according to the modified methodology M-T0-VTU0 10/09. Damage of the slab, the change of the ultrasound wave velocity propagation in the slab specimen before and after the blast load in certain measurement points, the weight of fragments and their damage potential were evaluated and compared. Realized tests confirmed the possibility of using the waste fibres for SIFCON technology. The obtained results indicate, that the usage of waste fibres does not significantly reduce the values of SIFCON flexural and compressive strength at quasi-static load - the values were comparable to the specimens with industrially produced fibres. With increasing fibre content, the mechanical parameters are increasing as well. Using of the waste fibres reduces fragmentation of SIFCON at blast load due to the fibre size parameters. Using of low diameter fibres means more fibres in the matrix and thus better homogeneity of the whole composite with less unreinforced areas. Regarding the blast tests, the specimen with waste steel fibres showed the best resistance and outperformed also the specimen with commercial fibres. Using of

Regularized iterative integration combined with non-linear diffusion filtering for phase-contrast x-ray computed tomography.

Science.gov (United States)

Burger, Karin; Koehler, Thomas; Chabior, Michael; Allner, Sebastian; Marschner, Mathias; Fehringer, Andreas; Willner, Marian; Pfeiffer, Franz; Noël, Peter

2014-12-29

Phase-contrast x-ray computed tomography has a high potential to become clinically implemented because of its complementarity to conventional absorption-contrast.In this study, we investigate noise-reducing but resolution-preserving analytical reconstruction methods to improve differential phase-contrast imaging. We apply the non-linear Perona-Malik filter on phase-contrast data prior or post filtered backprojected reconstruction. Secondly, the Hilbert kernel is replaced by regularized iterative integration followed by ramp filtered backprojection as used for absorption-contrast imaging. Combining the Perona-Malik filter with this integration algorithm allows to successfully reveal relevant sample features, quantitatively confirmed by significantly increased structural similarity indices and contrast-to-noise ratios. With this concept, phase-contrast imaging can be performed at considerably lower dose.

Discrete integration of continuous Kalman filtering equations for time invariant second-order structural systems

Science.gov (United States)

Park, K. C.; Belvin, W. Keith

1990-01-01

A general form for the first-order representation of the continuous second-order linear structural-dynamics equations is introduced to derive a corresponding form of first-order continuous Kalman filtering equations. Time integration of the resulting equations is carried out via a set of linear multistep integration formulas. It is shown that a judicious combined selection of computational paths and the undetermined matrices introduced in the general form of the first-order linear structural systems leads to a class of second-order discrete Kalman filtering equations involving only symmetric sparse N x N solution matrices.

An object-oriented language-database integration model: The composition filters approach

NARCIS (Netherlands)

Aksit, Mehmet; Bergmans, Lodewijk; Vural, Sinan; Vural, S.

1991-01-01

This paper introduces a new model, based on so-called object-composition filters, that uniformly integrates database-like features into an object-oriented language. The focus is on providing persistent dynamic data structures, data sharing, transactions, multiple views and associative access,

An Object-Oriented Language-Database Integration Model: The Composition-Filters Approach

NARCIS (Netherlands)

Aksit, Mehmet; Bergmans, Lodewijk; Vural, S.; Vural, Sinan; Lehrmann Madsen, O.

1992-01-01

This paper introduces a new model, based on so-called object-composition filters, that uniformly integrates database-like features into an object-oriented language. The focus is on providing persistent dynamic data structures, data sharing, transactions, multiple views and associative access,

Integrated hollow microneedle-optofluidic biosensor for therapeutic drug monitoring in sub-nanoliter volumes

Science.gov (United States)

Ranamukhaarachchi, Sahan A.; Padeste, Celestino; Dübner, Matthias; Häfeli, Urs O.; Stoeber, Boris; Cadarso, Victor J.

2016-07-01

Therapeutic drug monitoring (TDM) typically requires painful blood drawn from patients. We propose a painless and minimally-invasive alternative for TDM using hollow microneedles suitable to extract extremely small volumes (microneedle is functionalized to be used as a micro-reactor during sample collection to trap and bind target drug candidates during extraction, without requirements of sample transfer. An optofluidic device is integrated with this microneedle to rapidly quantify drug analytes with high sensitivity using a straightforward absorbance scheme. Vancomycin is currently detected by using volumes ranging between 50-100 μL with a limit of detection (LoD) of 1.35 μM. The proposed microneedle-optofluidic biosensor can detect vancomycin with a sample volume of 0.6 nL and a LoD of <100 nM, validating this painless point of care system with significant potential to reduce healthcare costs and patients suffering.

Towards an integrated simulation of casting and structural performance of flowable fibre-reinforced concrete

NARCIS (Netherlands)

Vidal Sarmiento, E.; Hendriks, M.A.N.; Geiker, M. R.; Kanstad, T.

2016-01-01

Most recent studies on fibre-reinforced self-compacting concrete agree on the impact of the casting conditions on the fibre orientation and distribution, and its consequence thereof on the structural performance. A substantial number of investigations are continuously contributing to gain experience

Optofluidic in-fiber interferometer based on hollow optical fiber with two cores.

Science.gov (United States)

Yuan, Tingting; Yang, Xinghua; Liu, Zhihai; Yang, Jun; Li, Song; Kong, Depeng; Qi, Xiuxiu; Yu, Wenting; Long, Qunlong; Yuan, Libo

2017-07-24

We demonstrate a novel integrated optical fiber interferometer for in-fiber optofluidic detection. It is composed of a specially designed hollow optical fiber with a micro-channel and two cores. One core on the inner surface of the micro-channel is served as sensing arm and the other core in the annular cladding is served as reference arm. Fusion-and-tapering method is employed to couple light from a single mode fiber to the hollow optical fiber in this device. Sampling is realized by side opening a microhole on the surface of the hollow optical fiber. Under differential pressure between the end of the hollow fiber and the microhole, the liquids can form steady microflows in the micro-channel. Simultaneously, the interference spectrum of the interferometer device shifts with the variation of the concentration of the microfluid in the channel. The optofluidic in-fiber interferometer has a sensitivity of refractive index around 2508 nm/RIU for NaCl. For medicine concentration detection, its sensitivity is 0.076 nm/mmolL -1 for ascorbic acid. Significantly, this work presents a compact microfluidic in-fiber interferometer with a micro-channel which can be integrated with chip devices without spatial optical coupling and without complex manufacturing procedure of the waveguide on the chips.

Novel Ultrafine Fibrous Poly(tetrafluoroethylene Hollow Fiber Membrane Fabricated by Electrospinning

Directory of Open Access Journals (Sweden)

Qinglin Huang

2018-04-01

Full Text Available Novel poly(tetrafluoroethylene (PTFE hollow fiber membranes were successfully fabricated by electrospinning, with ultrafine fibrous PTFE membranes as separation layers, while a porous glassfiber braided tube served as the supporting matrix. During this process, PTFE/poly(vinylalcohol (PVA ultrafine fibrous membranes were electrospun while covering the porous glassfiber braided tube; then, the nascent PTFE/PVA hollow fiber membrane was obtained. In the following sintering process, the spinning carrier PVA decomposed; meanwhile, the ultrafine fibrous PTFE membrane shrank inward so as to further integrate with the supporting matrix. Therefore, the ultrafine fibrous PTFE membranes had excellent interface bonding strength with the supporting matrix. Moreover, the obtained ultrafine fibrous PTFE hollow fiber membrane exhibited superior performances in terms of strong hydrophobicity (CA > 140°, high porosity (>70%, and sharp pore size distribution. The comprehensive properties indicated that the ultrafine fibrous PTFE hollow fiber membranes could have potentially useful applications in membrane contactors (MC, especially membrane distillation (MD in harsh water environments.

Effect of the preparation conditions on the properties of polyetherimide hollow fibre membranes for gas separation

Czech Academy of Sciences Publication Activity Database

Válek, R.; Malý, D.; Peter, Jakub; Gruart, M.

2017-01-01

Roč. 75, May (2017), s. 300-304 ISSN 1944-3994. [Membrane Conference of Visegrad Countries - PERMEA and International Conference on Membrane and Electromembrane Processes - MELPRO. Prague, 15.05.2016-19.05.2016] Institutional support: RVO:61389013 Keywords : hollow fiber membrane * asymetric membrane * design of experiments Subject RIV: CG - Electrochemistry OBOR OECD: Electrochemistry (dry cells, batteries, fuel cells, corrosion metals, electrolysis) Impact factor: 1.631, year: 2016 http://www.deswater.com/DWT_abstracts/vol_75/75_2017_300.pdf

Fibre illumination system

DEFF Research Database (Denmark)

2012-01-01

Source: EP2426402A The invention relates to a fibre illumination module and system for the collection and delivery of daylight for illumination purposes. The fibre illumination module comprises a plurality of collector elements, each collector element comprising an input fibre having a first end......-directional arrangement. The fibre illumination system comprises a fibre illumination module of the above-mentioned type. By the invention, daylight may be exploited for the illumination of remote interior spaces of buildings in order to save energy, and improve the well-being of users in both housing and working...

Influence of Cellulosic Fibres on the Physical Properties of Fibre Cement Composites

Science.gov (United States)

Hospodarova, V.; Stevulova, N.; Vaclavik, V.; Dvorsky, T.

2017-10-01

Nowadays, there are new approaches directing to processing of non-conventional fibre-cement composites for application in the housing construction. Vegetable cellulosic fibres coming from natural resources used as reinforcement in cost-effective and environmental friendly building products are in the spotlight. The applying of natural fibres in cement based composites is narrowly linked to the ecological building sector, where a choice of materials is based on components including recyclable, renewable raw materials and low-resource manufacture techniques. In this paper, two types of cellulosic fibres coming from wood pulp and recycled waste paper with 0.2%; 0.3% and 0.5% of fibre addition into cement mixtures were used. Differences in the physical characteristics (flowability, density, coefficient of thermal conductivity and water absorbability) of 28 days hardened fibre-cement composites are investigated. Addition of cellulosic fibres to cement mixture caused worsening the workability of fresh mixture as well as absorbability of hardened composites due to hydrophilic nature of biomaterial, whereas density and thermal conductivity of manufactured cement based fibre plaster are enhanced. The physical properties of cement plasters based on cellulosic fibres depend on structural, physical characteristics of cellulosic fibres, their nature and processing.

Dynamics of fibres in a turbulent flow field - A particle-level simulation technique

International Nuclear Information System (INIS)

Sasic, Srdjan; Almstedt, Alf-Erik

2010-01-01

A particle-level simulation technique has been developed for modelling the flow of fibres in a turbulent flow field. A single fibre is conceived here as a chain of segments, thus enabling the model fibre to have all the degrees of freedom (translation, rotation, bending and twisting) needed to realistically reproduce the dynamics of real fibres. Equations of motion are solved for each segment, accounting for the interaction forces with the fluid, the contact forces with other fibres and the forces that maintain integrity of the fibre. The motion of the fluid is resolved as a combination of 3D mean flow velocities obtained from a CFD code and fluctuating turbulent velocities derived from the Langevin equation. A case of homogeneous turbulence is treated in this paper. The results obtained show that fibre flocs in air-fibre flows can be created even when attractive forces are not present. In such a case, contacts between fibres, properties of an individual fibre (such as flexibility and equilibrium shapes) and properties of the flow of the carrying fluid are shown to govern the physics behind formation and breaking up of fibre flocs. Highly irregular fibre shapes and stiff fibres lead to strong flocculation. The modelling framework applied in this work aims at making possible a numerical model applicable for designing processes involving transport of fibres by air at industrial scale.

Pollution by air filters: Continuous vs intermittent air flow

NARCIS (Netherlands)

Cox, C.W.J.; Bluyssen, P.M.

2000-01-01

Within the framework of the EU research project Airless, a long-term experiment of 28 weeks was carried out to investigate the influence of intermittent airflow compared to continuous airflow on the pollution effect of glass fibre filters (F7). No statistical relevant differences between odour

Hollow-Core Fiber Lamp

Science.gov (United States)

Yi, Lin (Inventor); Tjoelker, Robert L. (Inventor); Burt, Eric A. (Inventor); Huang, Shouhua (Inventor)

2016-01-01

Hollow-core capillary discharge lamps on the millimeter or sub-millimeter scale are provided. The hollow-core capillary discharge lamps achieve an increased light intensity ratio between 194 millimeters (useful) and 254 millimeters (useless) light than conventional lamps. The capillary discharge lamps may include a cone to increase light output. Hollow-core photonic crystal fiber (HCPCF) may also be used.

Carbon nanotube filters

Science.gov (United States)

Srivastava, A.; Srivastava, O. N.; Talapatra, S.; Vajtai, R.; Ajayan, P. M.

2004-09-01

Over the past decade of nanotube research, a variety of organized nanotube architectures have been fabricated using chemical vapour deposition. The idea of using nanotube structures in separation technology has been proposed, but building macroscopic structures that have controlled geometric shapes, density and dimensions for specific applications still remains a challenge. Here we report the fabrication of freestanding monolithic uniform macroscopic hollow cylinders having radially aligned carbon nanotube walls, with diameters and lengths up to several centimetres. These cylindrical membranes are used as filters to demonstrate their utility in two important settings: the elimination of multiple components of heavy hydrocarbons from petroleum-a crucial step in post-distillation of crude oil-with a single-step filtering process, and the filtration of bacterial contaminants such as Escherichia coli or the nanometre-sized poliovirus (~25 nm) from water. These macro filters can be cleaned for repeated filtration through ultrasonication and autoclaving. The exceptional thermal and mechanical stability of nanotubes, and the high surface area, ease and cost-effective fabrication of the nanotube membranes may allow them to compete with ceramic- and polymer-based separation membranes used commercially.

Implicit Particle Filter for Power System State Estimation with Large Scale Renewable Power Integration.

Science.gov (United States)

Uzunoglu, B.; Hussaini, Y.

2017-12-01

Implicit Particle Filter is a sequential Monte Carlo method for data assimilation that guides the particles to the high-probability by an implicit step . It optimizes a nonlinear cost function which can be inherited from legacy assimilation routines . Dynamic state estimation for almost real-time applications in power systems are becomingly increasingly more important with integration of variable wind and solar power generation. New advanced state estimation tools that will replace the old generation state estimation in addition to having a general framework of complexities should be able to address the legacy software and able to integrate the old software in a mathematical framework while allowing the power industry need for a cautious and evolutionary change in comparison to a complete revolutionary approach while addressing nonlinearity and non-normal behaviour. This work implements implicit particle filter as a state estimation tool for the estimation of the states of a power system and presents the first implicit particle filter application study on a power system state estimation. The implicit particle filter is introduced into power systems and the simulations are presented for a three-node benchmark power system . The performance of the filter on the presented problem is analyzed and the results are presented.

Bacteria and Hoverflies (Diptera: Syrphidae) in Tree Hollows From the Iberian Mediterranean Forest.

Science.gov (United States)

Sánchez-Galván, I R; Ferrer, J; Galante, E; Marcos-García, M A

2017-02-01

Saproxylic insect communities inhabiting tree hollows in Mediterranean forests depend on a combination of physical characteristics and interactions occurring between community member species. Despite the need to preserve these organisms, little is known about their interrelationships, in particular those relationships between saproxylic insects and microbiota occurring in these microhabitats. In tree hollows of Quercus rotundifolia Lamark that hold water and contain dead leaves, abundant microbial populations can be found. Developing on them are the larvae of Mallota dusmeti Andréu, 1926 (Diptera: Syrphidae), a vulnerable species (IUCN category: Marcos-García and Quinto 2011). This study provides the first data on the microbiota living inside the gut of the larvae of M. dusmeti, as well as the microbiota in the hollow where these larvae develop. Bacteria were identified by amplification and partial sequencing of the V1-V3 regions and the complete nucleotide sequence of 16S rRNA genes. We found eight species of bacteria living in tree hollows and three species in the gut of M. dusmeti larvae: Bacillus cereus, Bacillus toyonensis, and Lysinibacillus sphaericus. The filter-feeding mechanism characteristic of M. dusmeti larvae is selective in enabling ingestion of bacteria only above 2.1 µm in diameter. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

A planar and tunable bandpass filter on a ferrite substrate with integrated windings

KAUST Repository

Arabi, Eyad A.

2015-05-01

Tunable Filters that are based on ferrite materials are often biased by external magnets or coils which are large and bulky. In this work a completely planar, CPW-based bandpass filter is presented with integrated windings. Due to these windings the size of the filter is only 26mm × 34mm × 0.38mm which is orders of magnitude smaller than the traditional designs with external windings. The filter is realized by electroplating of Copper over seed layers of Titanium and Gold over a YIG substrate. The fabricated filter achieves a tunability of 3.4% without any external magnets or coils. A good insertion loss of 2.3 dBs and rejection greater than 50 dBs have been obtained. To the best of the authors knowledge, this design is the first ferrite-based design that is completely planar and self-biased.

Photonic Crystal Fibres

DEFF Research Database (Denmark)

Bjarklev, Anders Overgaard; Broeng, Jes; Sanchez Bjarklev, Araceli

Photonic crystal fibres represent one of the most active research areas today in the field of optics. The diversity of applications that may be addressed by these fibres and their fundamental appeal, by opening up the possibility of guiding light in a radically new way compared to conventional...... optical fibres, have spun an interest from almost all areas of optics and photonics. The aim of this book is to provide an understanding of the different types of photonic crystal fibres and to outline some of the many new and exciting applications that these fibres offer. The book is intended for both...

Abaca fibre reinforced PP composites and comparison with jute and flax fibre PP composites

Directory of Open Access Journals (Sweden)

2007-11-01

Full Text Available Abaca fibre reinforced PP composites were fabricated with different fibre loadings (20, 30, 40, 50wt% and in some cases 35 and 45 wt%. Flax and jute fibre reinforced PP composites were also fabricated with 30 wt% fibre loading. The mechanical properties, odour emission and structure properties were investigated for those composites. Tensile, flexural and Charpy impact strengths were found to increase for fibre loadings up to 40 wt% and then decreased. Falling weight impact tests were also carried out and the same tendency was observed. Owing to the addition of coupling agent (maleated polypropylene -MAH-PP, the tensile, flexural and falling weight impact properties were found to increase in between 30 to 80% for different fibre loadings. When comparing jute and flax fibre composites with abaca fibre composites, jute fibre composites provided best tensile properties but abaca fibre polypropylene composites were shown to provide best notch Charpy and falling weight impact properties. Odours released by flax fibre composites were smaller than jute and abaca fibre composites.

Intrinsically narrowband pair photon generation in microstructured fibres

Energy Technology Data Exchange (ETDEWEB)

Clark, Alex; Bell, Bryn; Fulconis, Jeremie; Halder, Matthaeus M; Cemlyn, Ben; Rarity, John G [Centre for Communications Research, Department of Electrical and Electronic Engineering, University of Bristol, Merchant Venturers Building, Woodland Road, Bristol BS8 1UB (United Kingdom); Alibart, Olivier [Laboratoire de Physique de la Matiere Condensee, Unite Mixte de Recherche 6622, Centre National de la Recherche Scientifique, Universite de Nice-Sophia Antipolis, Parc Valrose 06108, Nice 2 (France); Xiong Chunle; Wadsworth, William J, E-mail: alex.clark@bristol.ac.uk [Centre for Photonics and Photonic Materials, Department of Physics, University of Bath, Claverton Down, Bath BA2 7AY (United Kingdom)

2011-06-15

In this paper, we study the tailoring of photon spectral properties generated by four-wave mixing in a birefringent photonic crystal fibre (PCF). The aim is to produce intrinsically narrow-band photons and hence to achieve high non-classical interference visibility and generate high-fidelity entanglement without any requirement for spectral filtering, leading to high effective detection efficiencies. We show unfiltered Hong-Ou-Mandel interference visibilities of 77% between photons from the same PCF and 80% between separate sources. We compare results from modelling the PCF to these experiments and analyse photon purities.

Dietary fibre fractions in cereal foods measured by a new integrated AOAC method.

Science.gov (United States)

Hollmann, Juergen; Themeier, Heinz; Neese, Ursula; Lindhauer, Meinolf G

2013-10-01

The reliable determination of soluble, insoluble and total dietary fibre in baked goods and cereal flours is an important issue for research, nutritional labelling and marketing. We compared total dietary fibre (TDF) contents of selected cereal based foods determined by AOAC Method 991.43 and the new AOAC Method 2009.01. Fifteen bread and bakery products were included in the study. Our results showed that TDF values of cereal products determined by AOAC Method 2009.01 were always significantly higher than those determined by AOAC Method 991.43. This was explained by the inclusion of low molecular weight soluble fibre fractions and resistant starch fractions in the TDF measurement by AOAC 2009.01. This documents that nutritional labelling of cereal products poses the challenge how to update TDF data in nutrient databases in a reasonable time with an acceptable expenditure. Copyright © 2013. Published by Elsevier Ltd.

Corrosion resistance of steel fibre reinforced concrete – a literature review

DEFF Research Database (Denmark)

Marcos Meson, Victor; Michel, Alexander; Solgaard, Anders

2016-01-01

Steel fibre reinforced concrete (SFRC) is increasingly being used in the construction of prefabricated segmental linings for bored tunnels, since it entails simplified production processes and higher quality standards. However, international standards and guidelines are not consistent regarding...... the consideration of steel fibres for the structural verification of SFRC elements exposed to corrosive environments, hampering the development of civil infrastructure built of SFRC. In particular, the long-term effect of exposure to chlorides is in focus and under discussion. This paper reviews the existing...... the existence of a critical crack width, below 0.20 mm, where corrosion of carbon-steel fibres is not critical and the structural integrity of the exposed SFRC can be ensured over the long-term. A doctoral project investigating chloride-induced corrosion of steel fibres on cracked SFRC has been initiated...

Creep properties of discontinuous fibre composites with partly creeping fibres

International Nuclear Information System (INIS)

Bilde-Soerensen, J.B.; Lilholt, H.

1977-05-01

In a previous report (RISO-M-1810) the creep properties of discontinuous fibre composites with non-creeping fibres were analyzed. In the present report this analysis is extended to include the case of discontinuous composites with partly creeping fibres. It is shown that the creep properties of the composite at a given strain rate, epsilonsub(c), depend on the creep properties of the matrix at a strain rate higher than epsilonsub(c), and on the creep properties of the fibres at epsilonsub(c). The composite creep law is presented in a form which permits a graphical determination of the composite creep curve. This can be constructed on the basis of the matrix and the fibre creep curves by vector operations in a log epsilon vs. log sigma diagram. The matrix contribution to the creep strength can be evaluated by a simple method. (author)

Aligned flax fibre/polylactate composites

DEFF Research Database (Denmark)

Madsen, Bo; Lilholt, Hans; Thygesen, Anders

2008-01-01

The potential of biocomposites in engineering applications is demonstrated by using aligned flax fibre/polylactate composites as a materials model system. The failure stress of flax fibres is measured by tensile testing of single fibres and fibre bundles. For both fibre configurations, it is found...... that failure stress is decreased by increasing the tested fibre volume. Based on two types of flax fibre preforms: carded sliver and unidirectional non-crimp fabric, aligned flax fibre/polylactate composites were fabricated with variable fibre content. The volumetric composition and tensile properties...... of the composite were measured. For composites with a fibre content of 37 % by volume, stiffness is about 20 GPa and failure stress is about 180 MPa. The tensile properties of the composites are analysed with a modified rule of mixtures model, which includes the effect of porosity. The experimental results...

Integrating retention soil filters into urban hydrologic models - Relevant processes and important parameters

Science.gov (United States)

Bachmann-Machnik, Anna; Meyer, Daniel; Waldhoff, Axel; Fuchs, Stephan; Dittmer, Ulrich

2018-04-01

Retention Soil Filters (RSFs), a form of vertical flow constructed wetlands specifically designed for combined sewer overflow (CSO) treatment, have proven to be an effective tool to mitigate negative impacts of CSOs on receiving water bodies. Long-term hydrologic simulations are used to predict the emissions from urban drainage systems during planning of stormwater management measures. So far no universally accepted model for RSF simulation exists. When simulating hydraulics and water quality in RSFs, an appropriate level of detail must be chosen for reasonable balancing between model complexity and model handling, considering the model input's level of uncertainty. The most crucial parameters determining the resultant uncertainties of the integrated sewer system and filter bed model were identified by evaluating a virtual drainage system with a Retention Soil Filter for CSO treatment. To determine reasonable parameter ranges for RSF simulations, data of 207 events from six full-scale RSF plants in Germany were analyzed. Data evaluation shows that even though different plants with varying loading and operation modes were examined, a simple model is sufficient to assess relevant suspended solids (SS), chemical oxygen demand (COD) and NH4 emissions from RSFs. Two conceptual RSF models with different degrees of complexity were assessed. These models were developed based on evaluation of data from full scale RSF plants and column experiments. Incorporated model processes are ammonium adsorption in the filter layer and degradation during subsequent dry weather period, filtration of SS and particulate COD (XCOD) to a constant background concentration and removal of solute COD (SCOD) by a constant removal rate during filter passage as well as sedimentation of SS and XCOD in the filter overflow. XCOD, SS and ammonium loads as well as ammonium concentration peaks are discharged primarily via RSF overflow not passing through the filter bed. Uncertainties of the integrated

Mechanical Property Analysis on Sandwich Structured Hybrid Composite Made from Natural Fibre, Glass Fibre and Ceramic Fibre Wool Reinforced with Epoxy Resin

Science.gov (United States)

Bharat, K. R.; Abhishek, S.; Palanikumar, K.

2017-06-01

Natural fibre composites find wide range of applications and usage in the automobile and manufacturing industries. They find lack in desired properties, which are required for present applications. In current scenario, many developments in composite materials involve the synthesis of Hybrid composite materials to overcome some of the lacking properties. In this present investigation, two sandwich structured hybrid composite materials have been made by reinforcing Aloe Vera-Ceramic Fibre Wool-Glass fibre with Epoxy resin matrix and Sisal fibre-Ceramic Fibre Wool-Glass fibre with Epoxy resin matrix and its mechanical properties such as Tensile, Flexural and Impact are tested and analyzed. The test results from the two samples are compared and the results show that sisal fibre reinforced hybrid composite has better mechanical properties than aloe vera reinforced hybrid composite.

An optimal method for producing low-stress fibre optic cables for astronomy

Science.gov (United States)

Murray, Graham; Tamura, Naoyuki; Takato, Naruhisa; Ekpenyong, Paul; Jenkins, Daniel; Leeson, Kim; Trezise, Shaun; Butterley, Timothy; Gunn, James; Ferreira, Decio; Oliveira, Ligia; Sodre, Laerte

2017-09-01

An increasing number of astronomical spectrographs employ optical fibres to collect and deliver light. For integral-field and high multiplex multi-object survey instruments, fibres offer unique flexibility in instrument design by enabling spectrographs to be located remotely from the telescope focal plane where the fibre inputs are deployed. Photon-starved astronomical observations demand optimum efficiency from the fibre system. In addition to intrinsic absorption loss in optical fibres, another loss mechanism, so-called focal ratio degradation (FRD) must be considered. A fundamental cause of FRD is stress, therefore low stress fibre cables that impart minimum FRD are essential. The FMOS fibre instrument for Subaru Telescope employed a highly effective cable solution developed at Durham University. The method has been applied again for the PFS project, this time in collaboration with a company, PPC Broadband Ltd. The process, planetary stranding, is adapted from the manufacture of large fibre-count, large diameter marine telecommunications cables. Fibre bundles describe helical paths through the cable, incorporating additional fibre per unit length. As a consequence fibre stress from tension and bend-induced `race-tracking' is minimised. In this paper stranding principles are explained, covering the fundamentals of stranded cable design. The authors describe the evolution of the stranding production line and the numerous steps in the manufacture of the PFS prototype cable. The results of optical verification tests are presented for each stage of cable production, confirming that the PFS prototype performs exceptionally well. The paper concludes with an outline of future on-telescope test plans.

COMPUTING THERAPY FOR PRECISION MEDICINE: COLLABORATIVE FILTERING INTEGRATES AND PREDICTS MULTI-ENTITY INTERACTIONS.

Science.gov (United States)

Regenbogen, Sam; Wilkins, Angela D; Lichtarge, Olivier

2016-01-01

Biomedicine produces copious information it cannot fully exploit. Specifically, there is considerable need to integrate knowledge from disparate studies to discover connections across domains. Here, we used a Collaborative Filtering approach, inspired by online recommendation algorithms, in which non-negative matrix factorization (NMF) predicts interactions among chemicals, genes, and diseases only from pairwise information about their interactions. Our approach, applied to matrices derived from the Comparative Toxicogenomics Database, successfully recovered Chemical-Disease, Chemical-Gene, and Disease-Gene networks in 10-fold cross-validation experiments. Additionally, we could predict each of these interaction matrices from the other two. Integrating all three CTD interaction matrices with NMF led to good predictions of STRING, an independent, external network of protein-protein interactions. Finally, this approach could integrate the CTD and STRING interaction data to improve Chemical-Gene cross-validation performance significantly, and, in a time-stamped study, it predicted information added to CTD after a given date, using only data prior to that date. We conclude that collaborative filtering can integrate information across multiple types of biological entities, and that as a first step towards precision medicine it can compute drug repurposing hypotheses.

Shrinking of bumps by drawing scintillating fibres through a hot conical tool

CERN Document Server

Rodrigues Cavalcante, Ana Barbara; Gavardi, Laura; Joram, Christian; Kristic, Robert; Pierschel, Gerhard; Schneider, Thomas

2016-01-01

The LHCb SciFi tracker will be based on scintillating fibres with a nominal diameter of 250 $\\mu$m. A small length fraction of these fibres shows millimetre-scale fluctuations of the diameter, also known as bumps and necks. In particular, bumps exceeding a diameter of about 350 $\\mu$m are problematic as they can distort the winding pattern of the fibre mats over more extended regions. We present a method to reduce the diameter of large bumps to a diameter of 350 $\\mu$m by locally heating and pulling the fibre through a conical tool. The method has been proven to work for bumps up to 450 – 500 $\\mu$m diameter. Larger bumps need to be treated manually by a cut-and-glue technique which relies on UV-curing instant glue. The bump shrinking and cut-and-glue processes were integrated in a fibre diameter scanner at CERN. The central scanning and bump shrinking of all fibres is expected to minimise bump related issues at the four mat winding centres of the SciFi project.

The efficiency of Whatman Type ACG/B filter papers for methyl iodine retention in air

International Nuclear Information System (INIS)

Davis, R.E.; Williams, J.M.E.

1965-11-01

Experiments are described in which charcoal impregnated glass fibre filter papers Type ACG/B were exposed to methyl iodide vapour and the penetration determined for iodide loadings ranging from 2 x 10 - 7 to 2x10 - 1 μg/cm 2 of filter area. Air was subsequently passed through the filters, and at intervals the amount of methyl iodide remaining on them was determined. Penetrations during loading varied from 30% to 80%, but after 10 minutes elution all filters retained less than 5% of the methyl iodide originally present. (author)

Influence of fibre design and curvature on crosstalk in multi-core fibre

International Nuclear Information System (INIS)

Egorova, O N; Astapovich, M S; Semjonov, S L; Dianov, E M; Melnikov, L A; Salganskii, M Yu; Mishkin, S N; Nishchev, K N

2016-01-01

We have studied the influence of cross-sectional structure and bends on optical cross-talk in a multicore fibre. A reduced refractive index layer produced between the cores of such fibre with a small centre-to-centre spacing between neighbouring cores (27 μm) reduces optical cross-talk by 20 dB. The cross-talk level achieved, 30 dB per kilometre of the length of the multicore fibre, is acceptable for a number of applications where relatively small lengths of fibre are needed. Moreover, a significant decrease in optical cross-talk has been ensured by reducing the winding diameter of multicore fibres with identical cores. (fiber optics)

Influence of fibre design and curvature on crosstalk in multi-core fibre

Energy Technology Data Exchange (ETDEWEB)

Egorova, O N; Astapovich, M S; Semjonov, S L; Dianov, E M [Fiber Optics Research Center, Russian Academy of Sciences, Moscow (Russian Federation); Melnikov, L A [Kotel' nikov Institute of Radio Engineering and Electronics, Russian Academy of Sciences, Saratov Branch, Saratov (Russian Federation); Salganskii, M Yu [G.G.Devyatykh Institute of Chemistry of High-Purity Substances, Russian Academy of Sciences, Nizhnii Novgorod (Russian Federation); Mishkin, S N; Nishchev, K N [N.P. Ogarev Mordovia State University, Physics and Chemistry Institute, Saransk (Russian Federation)

2016-03-31

We have studied the influence of cross-sectional structure and bends on optical cross-talk in a multicore fibre. A reduced refractive index layer produced between the cores of such fibre with a small centre-to-centre spacing between neighbouring cores (27 μm) reduces optical cross-talk by 20 dB. The cross-talk level achieved, 30 dB per kilometre of the length of the multicore fibre, is acceptable for a number of applications where relatively small lengths of fibre are needed. Moreover, a significant decrease in optical cross-talk has been ensured by reducing the winding diameter of multicore fibres with identical cores. (fiber optics)

Studies of the Fission Integrals of U-{sup 235} and Pu-{sup 239} with Cadmium and Filters

Energy Technology Data Exchange (ETDEWEB)

Hellstrand, E

1965-04-15

The resonance fissions in U{sup 235} and Pu{sup 239} have been studied using cadmium and boron filters. Fission chambers were used as detectors and the experiments were performed in beam geometry. The neutron energy distribution in the beams transmitted through the different filters was determined with a fast chopper. From the cadmium filter, measurements the fission resonance integrals were determined. The values obtained were 278{+-}9 b for U{sup 235} and 301{+-}10 b for Pu{sup 239}; 0.5 eV < E < 1 MeV. Complementary Pu{sup 239} measurements were made in which the fission events were detected from the fission product activity in irradiated foils. Contrary to what has been reported elsewhere the value of the Pu{sup 239} resonance integral, found in this way, agreed well with that obtained from the fission chamber measurement. The experiments with the boron filters yielded results which, for the thin filter, agreed well with those calculated from the cross section data given in the Karlsruhe compilation. The discrepancy was larger for the thick filter but the values did not disagree outside the common limits of error.

Fibre-Related Dietary Patterns: Socioeconomic Barriers to Adequate Fibre Intake in Polish Adolescents. A Short Report.

Science.gov (United States)

Krusinska, Beata; Kowalkowska, Joanna; Wadolowska, Lidia; Wuenstel, Justyna Weronika; Slowinska, Malgorzata Anna; Niedzwiedzka, Ewa

2017-06-10

There is no complete explanation for the association between socioeconomic status (SES), fibre, and whole diet described by dietary patterns. The aim of this short report was to increase the understanding of adolescent dietary patterns related to fibre in their social context. A cross-sectional study was conducted involving 1176 adolescents aged 13-18 years from central and north-eastern Poland. The overall SES was composed of five single factors: place of residence, self-declared economic situation of family, self-declared economic situation of household, paternal and maternal education. The consumption frequency of nine dietary fibre sources was collected using Block's questionnaire and was expressed in points. Fibre dietary patterns (DPs) were drawn by cluster analysis and odds ratios (ORs) adjusted for age, sex, and BMI were calculated. Three fibre-related DPs were identified: "High-fibre" (mean frequency of total fibre intake 22.7 points; range: 0-36), "Average-fibre" (17.7 points), "Low-fibre" (14.6 points). The "High-fibre" DP was characterized by a relatively higher frequency consumption of white bread, fruit, fruit or vegetable juices, potatoes, green salad and prepared vegetables, and a moderate frequency consumption of high-fibre or bran cereals and wholegrain bread compared to the "Low-fibre" DP. The "Average-fibre" DP was characterized by a relatively higher frequency consumption of wholegrain bread and high-fibre or bran cereals and a moderate frequency consumption of fruit, fruit or vegetable juices, green salad and prepared vegetables compared to the "Low-fibre" DP. Less likely to adhere to the "High-fibre" DP were adolescents with low SES (OR: 0.55, 95% CI: 0.39-0.77) or average SES (0.58, 95% CI: 0.41-0.81) in comparison with high SES (reference) as a result of elementary or secondary paternal or maternal education, rural residence, and lower household economic situation. Similar associations were found for the "Average-fibre" DP. Low and average

Polymorphism of myofibrillar proteins of rabbit skeletal-muscle fibres. An electrophoretic study of single fibres.

OpenAIRE

Salviati, G; Betto, R; Danieli Betto, D

1982-01-01

Rabbit predominantly fast-twitch-fibre and predominantly slow-twitch-fibre skeletal muscles of the hind limbs, the psoas, the diaphragm and the masseter muscles were fibre-typed by one-dimensional polyacrylamide-gel electrophoresis of the myofibrillar proteins of chemically skinned single fibres. Investigation of the distribution of fast-twitch-fibre and slow-twitch-fibre isoforms of myosin light chains and the type of myosin heavy chains, based on peptide 'maps' published in Cleveland. Fisch...

Evaluation of the filtered leapfrog-trapezoidal time integration method

International Nuclear Information System (INIS)

Roache, P.J.; Dietrich, D.E.

1988-01-01

An analysis and evaluation are presented for a new method of time integration for fluid dynamic proposed by Dietrich. The method, called the filtered leapfrog-trapezoidal (FLT) scheme, is analyzed for the one-dimensional constant-coefficient advection equation and is shown to have some advantages for quasi-steady flows. A modification (FLTW) using a weighted combination of FLT and leapfrog is developed which retains the advantages for steady flows, increases accuracy for time-dependent flows, and involves little coding effort. Merits and applicability are discussed

Preparation of TiO2 hollow fibers using poly(vinylidene fluoride) hollow fiber microfiltration membrane as a template

International Nuclear Information System (INIS)

Lu Haiqiang; Zhang Lixiong; Xing Weihong; Wang Huanting; Xu Nanping

2005-01-01

TiO 2 hollow fibers were successfully prepared by using poly(vinylidene fluoride) hollow fiber microfiltration membrane as a template. The preparation procedure includes repeated impregnation of the TiO 2 precursor in the pores of the polymeric membrane, and calcination to burn off the template, producing the TiO 2 hollow fibers. The TiO 2 hollow fibers were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). TiO 2 hollow fibers with other structures, such as honeycomb monolith and spring, were also prepared by preshaping the polymeric membranes into the honeycomb structure and spring, respectively. The phase structure of the TiO 2 hollow fibers could be readily adjusted by changing the calcination temperature

Influence of fibre orientation on the performance of steel fibre-reinforced concrete

OpenAIRE

Grünewald, Steffen; Laranjeira de Oliveira, Filipe; Walraven, Joost; Aguado de Cea, Antonio; Molins i Borrell, Climent

2012-01-01

The performance of fibre-reinforced materials in the hardened state depends on the material behaviour, the production method and influences related to the structure. The position and the orientation of fibres in a structure can differ from the homogenous distribution and the random orientation in a mixer. Due to the flow of the concrete, fibres are able to orient which makes the prediction of the structural behaviour of fibre-reinforced concrete more complex, but it also offers the potential ...

WORKSHOP: Scintillating fibre detectors

International Nuclear Information System (INIS)

Anon.

1989-01-01

Scintillating fibre detector development and technology for the proposed US Superconducting Supercollider, SSC, was the subject of a recent workshop at Fermilab, with participation from the high energy physics community and from industry. Sessions covered the current status of fibre technology and fibre detectors, new detector applications, fluorescent materials and scintillation compositions, radiation damage effects, amplification and imaging structures, and scintillation fibre fabrication techniques

Hemp fibres: Enzymatic effect of microbial processing on fibre bundle structure

DEFF Research Database (Denmark)

Thygesen, Anders; Liu, Ming; Meyer, Anne S.

2013-01-01

The effects of microbial pretreatment on hemp fibres were evaluated after microbial retting using the white rot fungi Ceriporiopsis subvermispora and Phlebia radiata Cel 26 and water retting. Based on chemical composition, P. radiata Cel 26 showed the highest selectivity for pectin and lignin...... degradation and lowest cellulose loss (14%) resulting in the highest cellulose content (78.4%) for the treated hemp fibres. The pectin and lignin removal after treatment with P. radiata Cel 26 were of the order 82% and 50%, respectively. Aligned epoxy-matrix composites were made from hemp fibres defibrated...... with the microbial retting to evaluate the effects on their ultrastructure. SEM microscopy of the composites showed low porosity on the fibre surfaces after defibration with P. radiata Cel 26 and C. subvermispora indicating good epoxy polymer impregnation. In contrast, fibres treated by water retting and the raw...

Vibrated and self-compacting fibre reinforced concrete: experimental investigation on the fibre orientation

Science.gov (United States)

Conforti, A.; Plizzari, G. A.; Zerbino, R.

2017-09-01

In addition to the fibre type and content, the residual properties of fibre reinforced concrete are influenced by fibre orientation. Consequently, the performance fibre reinforced concrete can be affected by its fresh properties (workability, flowing capacity) and by casting and compaction processes adopted. This paper focuses on the study of the orientation of steel or macro-synthetic fibres in two materials characterized by very different fresh properties: vibrated and self-compacting concrete. Four rectangular slabs 1800 mm long, 925 mm wide and 100 mm high were produced changing concrete and fibre type. From each slab, eighteen small prisms (550 mm long) were firstly cut either orthogonal or parallel to casting direction and, secondly, notched and tested in bending according to EN 14651. Experimental results showed that the toughness properties of a thin slab significantly varies both in vibrated and self-compacting concrete, even if in case of self-compacting concrete this variation resulted higher. Steel fibres led to greater variability of results compared to polymer one, underlining a different fibre orientation. A discussion on the relative residual capacity measured on the prisms sawn from the slabs and the parameters obtained from standard specimens is performed.

Degradation of basalt fibre and glass fibre/epoxy resin composites in seawater

International Nuclear Information System (INIS)

Wei Bin; Cao Hailin; Song Shenhua

2011-01-01

Research highlights: → BFRP degradation process in seawater environment was first investigated. → The mass gain change includes two effects: absorption and extraction. → The interfacial adhesion of BFRP is bigger than GFRP. → After treated, the bending strength of BFRP is lower than GFRP. → Reducing the Fe 2+ in the basalt fibre could lead to a higher stability of BFRP. - Abstract: Epoxy resins reinforced, respectively, by basalt fibres and glass fibres were treated with a seawater solution for different periods of time. Both the mass gain ratio and the strength maintenance ratio of the composites were examined after the treatment. The fracture surfaces were characterized using scanning electron microscopy. The tensile and bending strengths of the seawater treated samples showed a decreasing trend with treating time. In general, the anti-seawater corrosion property of the basalt fibre reinforced composites was almost the same as that of the glass fibre reinforced ones. Based on the experimental results, possible corrosion mechanisms were explored, indicating that an effective lowering of the Fe 2+ content in the basalt fibre could lead to a higher stability for the basalt fibre reinforced composites in a seawater environment.

Electrically conducting fibres for e-textiles : An open playground for conjugated polymers and carbon nanomaterials

NARCIS (Netherlands)

Lund, Anja; van der Velden, N.M.; Persson, Nils-Krister; Hamedi, Mahiar M.; Müller, Christian

2018-01-01

Conducting fibres and yarns promise to become an essential part of the next generation of wearable electronics that seamlessly integrate electronic function into one of the most versatile and most widely used form of materials: textiles. This review explores the many types of conducting fibres

Hydrogel–fibre composites with independent control over cell adhesion to gel and fibres as an integral approach towards a biomimetic artificial ECM

International Nuclear Information System (INIS)

Schulte, Vera A; Dhanasingh, Anandhan; Hahn, Kathrin; Heffels, Karl-Heinz; Groll, Jürgen

2014-01-01

In the body, cells are surrounded by an interconnected mesh of insoluble, bioactive protein fibres to which they adhere in a well-controlled manner, embedded in a hydrogel-like highly hydrated matrix. True morphological and biochemical mimicry of this so-called extracellular matrix (ECM) remains a challenge but appears decisive for a successful design of biomimetic three-dimensional in vitro cell culture systems. Herein, an approach is presented which describes the fabrication and in vitro assessment of an artificial ECM which contains two major components, i.e. specifically biofunctionalized fibres and a semi-synthetic hyaluronic acid-based hydrogel, which allows control over cell adhesion towards both components. As proof of principle for the control of cell adhesion, RGD as well-known cell adhesive cue and the control sequence RGE are immobilized in the system. In vitro studies with primary human dermal fibroblasts were conducted to evaluate the specificity of cell adhesion and the potential of the composite system to support cell growth. Finally, one possible application example for guided cell growth is shown by the use of oriented fibres in a hydrogel matrix. (paper)

The Chemical Composition of Grape Fibre

Directory of Open Access Journals (Sweden)

Jolana Karovičová

2015-05-01

Full Text Available Dietary fibres from cereals are much more used than dietary fibres from fruits; however, dietary fibres from fruits have better quality. In recent years, for economic and environmental reasons, there has been a growing pressure to recover and exploit food wastes. Grape fibre is used to fortify baked goods, because the fibre can lower blood sugar, cut cholesterol and may even prevent colon cancer. Grape pomace is a functional ingredient in bakery goods to increase total phenolic content and dietary fibre in nourishment. The aim of this study was to determine the chemical composition of commercial fibres, obtained from different Grape sources concerning their chemical properties such as moisture, ash, fat, protein, total dietary fibre. The chemical composition of Grape fibre is known to vary depending on the Grape cultivar, growth climates, and processing conditions. The obliged characteristics of the fibre product are: total dietary fibre content above 50%, moisture lower than 9%, low content of lipids, a low energy value and neutral flavour and taste. Grape pomace represents a rich source of various high-value products such as ethanol, tartrates and malates, citric acid, Grape seed oil, hydrocolloids and dietary fibre. Used commercial Grape fibres have as a main characteristic, the high content of total dietary fibre. Amount of total dietary fibre depends on the variety of Grapes. Total dietary fibre content (TDF in our samples of Grape fibre varied from 56.8% to 83.6%. There were also determined low contents of moisture (below 9%. In the samples of Grape fibre were determined higher amount of protein (8.6 - 10.8%, mineral (1.3 - 3.8% and fat (2.8 - 8.6%. This fact opens the possibility of using both initial by-products as ingredients in the food industry, due to the effects associated with the high total dietary fibre content.

Hollow Micro-/Nanostructures: Synthesis and Applications

KAUST Repository

Lou, Xiong Wen (David)

2008-11-03

Hollow micro-nanostructures are of great interest in many current and emerging areas of technology. Perhaps the best-known example of the former is the use of fly-ash hollow particles generated from coal power plants as partial replacement for Portland cement, to produce concrete with enhanced strength and durability. This review is devoted to the progress made in the last decade in synthesis and applications of hollow micro-nanostructures. We present a comprehensive overview of synthetic strategies for hollow structures. These strategies are broadly categorized into four themes, which include well-established approaches, such as conventional hard-templating and soft-templating methods, as well as newly emerging methods based on sacrificial templating and template-free synthesis. Success in each has inspired multiple variations that continue to drive the rapid evolution of the field. The Review therefore focuses on the fundamentals of each process, pointing out advantages and disadvantages where appropriate. Strategies for generating more complex hollow structures, such as rattle-type and nonspherical hollow structures, are also discussed. Applications of hollow structures in lithium batteries, catalysis and sensing, and biomedical applications are reviewed. © 2008 WILEY-VCH Verlag GmbH & Co. KGaA,.

A simple pendulum borehole tiltmeter based on a triaxial optical-fibre displacement sensor

Science.gov (United States)

Chawah, P.; Chéry, J.; Boudin, F.; Cattoen, M.; Seat, H. C.; Plantier, G.; Lizion, F.; Sourice, A.; Bernard, P.; Brunet, C.; Boyer, D.; Gaffet, S.

2015-11-01

Sensitive instruments like strainmeters and tiltmeters are necessary for measuring slowly varying low amplitude Earth deformations. Nonetheless, laser and fibre interferometers are particularly suitable for interrogating such instruments due to their extreme precision and accuracy. In this paper, a practical design of a simple pendulum borehole tiltmeter based on laser fibre interferometric displacement sensors is presented. A prototype instrument has been constructed using welded borosilicate with a pendulum length of 0.85 m resulting in a main resonance frequency of 0.6 Hz. By implementing three coplanar extrinsic fibre Fabry-Perot interferometric probes and appropriate signal filtering, our instrument provides tilt measurements that are insensitive to parasitic deformations caused by temperature and pressure variations. This prototype has been installed in an underground facility (Rustrel, France) where results show accurate measurements of Earth strains derived from Earth and ocean tides, local hydrologic effects, as well as local and remote earthquakes. The large dynamic range and the high sensitivity of this tiltmeter render it an invaluable tool for numerous geophysical applications such as transient fault motion, volcanic strain and reservoir monitoring.

Microgel polymer composite fibres

OpenAIRE

Kehren, Dominic

2014-01-01

In this thesis some novel ideas and advancements in the field of polymer composite fibres, specifically microgel-based polymer composite fibres have been achieved. The main task was to investigate and understand the electrospinning process of microgels and polymers and the interplay of parameter influences, in order to fabricate reproducible and continuously homogenous composite fibres. The main aim was to fabricate a composite material which combines the special properties of polymer fibres ...

Separation of Am(III) from SHLW using a hollow fiber supported liquid membrane containing TODGA as the carrier

International Nuclear Information System (INIS)

Ansari, S.A.; Raut, D.R.; Mohapatra, P.K.; Manchanda, V.K.

2008-01-01

Facilitated transport of Am(III) from nitrate medium has been investigated through a hollow fibre supported liquid membrane using N,N,N',N'-tetraoctyl diglycolamide (TODGA) as the carrier. The influence of aqueous feed composition on the permeability of Am(III) is reported. Quantitative transport of Am(III) was observed in 45 min from a feed solution containing 1g/l Nd(III) at 3.5M HNO 3 . Similarly, quantitative transport of Am(III) was observed in 30 min from a synthetic high level waste containing ∼0.6g/l total lanthanides, in addition to the other non-extractable metal ions. (author)

Embedding silica and polymer fibre Bragg gratings (FBG) in plastic 3D-printed sensing patches

DEFF Research Database (Denmark)

Zubel, Michal G.; Sugden, Kate; Webb, David J.

2016-01-01

This paper reports the first demonstration of a silica fibre Bragg grating (SOFBG) embedded in an FDM 3-D printed housing to yield a dual grating temperature-compensated strain sensor. We also report the first ever integration of polymer fibre Bragg grating (POFBG) within a 3-D printed sensing...

Modelling of photonic crystal fibres

DEFF Research Database (Denmark)

Knudsen, Erik

2003-01-01

, as well as a honeycomb bandgap fibre and the first analysis of semi-periodic layered air-hole fibres. Using the modelling framework established as a basis, we provide an analysis of microbend loss, by regarding displacement of a fibre core as a stationary stochastic process, inducing mismatch between......In the presenta ph.d. work a theoretical study of aspects of modelling photonic crystal fibres was carried out. Photonic crystal fibres form a class of optical waveguides where guidance is no longer provided by a difference in refractive index between core and cladding. Instead, guidance...... is provided by an arrangement of air-holes running along the length of the fibre. Depending on the geometry of the fibre, the guiding mechanism may be either arising from the formation of a photonic bandgap in the cladding structure (photonic bandgap fibre), or by an effect resembling total internal...

Surface analysis of glass fibres using XPS and AFM: case study of glass fibres recovered from the glass fibre reinforced polymer using chemical recycling

Science.gov (United States)

Nzioka, A. M.; Kim, Y. J.

2018-01-01

In this study, we present the results of an experimental study of the use of the X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) to characterise the coatings of the recovered E - glass fibres. The recovered E - glass fibres were obtained using chemical recycling process coupled with ultrasound cavitation. The objective of this study was to analyse the impact of chemical recycling and the ultrasound cavitation process on the sizing properties of the recovered fibres. We obtained the recovered fibres and sized using 1 wt% 3 - aminopropyltriethoxysilane (APS). Part of the sized fibres was washed with acetone and analysed all the sample fibres using AFM and XPS. Results showed the different composition of sizing after extraction using acetone. We compared the results of this study with that of virgin clean glass fibres.

An integral equation method for the homogenization of unidirectional fibre-reinforced media; antiplane elasticity and other potential problems.

Science.gov (United States)

Joyce, Duncan; Parnell, William J; Assier, Raphaël C; Abrahams, I David

2017-05-01

In Parnell & Abrahams (2008 Proc. R. Soc. A 464 , 1461-1482. (doi:10.1098/rspa.2007.0254)), a homogenization scheme was developed that gave rise to explicit forms for the effective antiplane shear moduli of a periodic unidirectional fibre-reinforced medium where fibres have non-circular cross section. The explicit expressions are rational functions in the volume fraction. In that scheme, a (non-dilute) approximation was invoked to determine leading-order expressions. Agreement with existing methods was shown to be good except at very high volume fractions. Here, the theory is extended in order to determine higher-order terms in the expansion. Explicit expressions for effective properties can be derived for fibres with non-circular cross section, without recourse to numerical methods. Terms appearing in the expressions are identified as being associated with the lattice geometry of the periodic fibre distribution, fibre cross-sectional shape and host/fibre material properties. Results are derived in the context of antiplane elasticity but the analogy with the potential problem illustrates the broad applicability of the method to, e.g. thermal, electrostatic and magnetostatic problems. The efficacy of the scheme is illustrated by comparison with the well-established method of asymptotic homogenization where for fibres of general cross section, the associated cell problem must be solved by some computational scheme.

Biological durability and oxidative potential of man-made vitreous fibres as compared to crocidolite asbestos fibres

Energy Technology Data Exchange (ETDEWEB)

Hippeli, S.; Dornisch, K.; Elstner, E.F. [Lehrstuhl fuer Phytopathologie, Technische Univ. Muenchen-Weihenstephan, Freising-Weihenstephan (Germany); Wiethege, T.; Mueller, K.M. [Berufsgenossenschaftliche Kliniken Bergmannsheil, Universitaetsklinik, Inst. fuer Pathologie, Bochum (Germany); Gillissen, A. [Medizinische Universitaetsklinik und Poliklinik II, Kardiologie, Pneumologie, Bonn (Germany)

2001-08-01

In this study we investigated relationships between redox properties and biodurability of crocidolite asbestos fibres and three different man-made vitreous fibres (MMVF): traditional stone wool fibres (MMVF 21), glass fibres (MMVF 11) and refractory ceramic fibres (RCF). Each fibre type was incubated up to 22 weeks in four different incubation media: gamble solution (GS) pH 5.0 and pH 7.4, representing blood plasma without proteins, and surfactant-like solution (SLS) pH 5.0 and pH 7.4. During incubation time aliquots of incubation mixtures were removed and analysed in a biochemical model reaction, mimicking activated phagocytes. In addition, changes of fibre morphology and chemical composition were examined using SEM- and EDX-technology. In the presence of crocidolite asbestos fibres and MMVF 21 the formation of OH-radicals according to the Haber-Weiss sequence could be demonstrated, whereas MMVF 11 and RCF showed no reactivity. Crocidolite asbestos fibres exhibited a significant higher activity compared with the stone wool fibres at the onset of incubation. The oxidative capacities of these fibre types were shown to depend on both specific surface area and iron content. The oxidative potentials of crocidolite asbestos fibres as well as MMVF 21 were not constant during incubation over several weeks in each incubation medium. The reactivities showed sinoidal curves including reactivities much higher than those at the onset of incubation time. These irregular changes of oxidative capacity may be explained by changes of the redox state of fibre surface-complexed iron. Furthermore our results showed clear differences between incubation of fibres in GS and SLS, respectively, indicating that phospholipids play an important part in fibre dissolution behaviour and oxidative reactivity. (orig.)

Acousto-optic mode coupling excited by flexural waves in simplified hollow-core photonic crystal fibers

International Nuclear Information System (INIS)

Zhang, Hao; Qiu, Minghui; Wu, Zhifang; Dong, Hongguang; Liu, Bo; Miao, Yinping

2013-01-01

We have demonstrated the formation of an acoustic grating in a simplified hollow-core photonic crystal fiber, which consists of a hollow hexagonal core and six crown-like air holes, by applying flexural acoustic waves along the fiber axis. The dependence of the resonance wavelength on the applied acoustic frequency has been acquired on the basis of the theoretical calculation of the phase matching curve; it is in good agreement with our experimental observation of the transmission spectral evolution as the applied acoustic frequency varies. Experimental results show that the acoustic grating resonance peak possesses acoustic frequency and strain dependences of 728 nm MHz −1 and −6.98 pm με −1 , respectively, based on which high-performance acousto-optic tunable filters and fiber-optic strain sensors with high sensitivity could be achieved. And furthermore, the research work presented in this paper indicates that microbending rather than physical deformation is the main physical mechanism that leads to the formation of equivalent long-period gratings, which would be of significance for developing related grating devices based on simplified hollow-core photonic crystal fibers. (paper)

Pure chiral optical fibres.

Science.gov (United States)

Poladian, L; Straton, M; Docherty, A; Argyros, A

2011-01-17

We investigate the properties of optical fibres made from chiral materials, in which a contrast in optical activity forms the waveguide, rather than a contrast in the refractive index; we refer to such structures as pure chiral fibres. We present a mathematical formulation for solving the modes of circularly symmetric examples of such fibres and examine the guidance and polarisation properties of pure chiral step-index, Bragg and photonic crystal fibre designs. Their behaviour is shown to differ for left- and right-hand circular polarisation, allowing circular polarisations to be isolated and/or guided by different mechanisms, as well as differing from equivalent non-chiral fibres. The strength of optical activity required in each case is quantified.

LiFi: transforming fibre into wireless

Science.gov (United States)

Yin, Liang; Islim, Mohamed Sufyan; Haas, Harald

2017-01-01

Light-fidelity (LiFi) uses energy-efficient light-emitting diodes (LEDs) for high-speed wireless communication, and it has a great potential to be integrated with fibre communication for future gigabit networks. However, by making fibre communication wireless, multiuser interference arises. Traditional methods use orthogonal multiple access (OMA) for interference avoidance. In this paper, multiuser interference is exploited with the use of non-orthogonal multiple access (NOMA) relying on successive interference cancellation (SIC). The residual interference due to imperfect SIC in practical scenarios is characterized with a proportional model. Results show that NOMA offers 5 -10 dB gain on the equivalent signal-to-interference-plus-noise ratio (SINR) over OMA. The bit error rate (BER) performance of direct current optical orthogonal frequency division multiplexing (DCO-OFDM) is shown to be significantly improved when SIC is used.

Integrated organic electronic based optochemical sensors using polarization filters

International Nuclear Information System (INIS)

Kraker, Elke; Haase, Anja; Lamprecht, Bernhard; Jakopic, Georg; Konrad, Christian; Koestler, Stefan

2008-01-01

A compact, integrated photoluminescence based oxygen and pH sensor, utilizing an organic light emitting device (OLED) as the light source and an organic photodiode (OPD) as the detection unit, is described. The main challenge in such an integrated sensor is the suppression of the excitation light at the detector, which is typically by many orders of magnitude higher in intensity than the emitted fluorescence. In our approach, we refrain from utilizing edge filters which require narrow band excitation sources and dyes with an adequate large Stokes shift. We rather developed an integrated sensor concept relying on two polarizers to separate the emission and excitation light. One polarizer is located right after the OLED, while the other one, oriented at 90 deg. to the first, is placed in front of the OPD. The main advantage of this solution is that any combination of excitation and emission light is acceptable, even if the two signals overlap spectrally. This is especially important for the use of OLEDs as the excitation sources, as these devices typically exhibit a broad spectral emission

Laboratory-scale integrated ARP filter test

Energy Technology Data Exchange (ETDEWEB)

Poirier, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Burket, P. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2016-03-01

The Savannah River Site (SRS) is currently treating radioactive liquid waste with the Actinide Removal Process (ARP) and the Modular Caustic Side Solvent Extraction Unit (MCU). Recently, the low filter flux through the ARP of approximately 5 gallons per minute has limited the rate at which radioactive liquid waste can be treated. Salt Batch 6 had a lower processing rate and required frequent filter cleaning. There is a desire to understand the causes of the low filter flux and to increase ARP/MCU throughput. This task attempted to simulate the entire ARP process, including multiple batches (5), washing, chemical cleaning, and blending the feed with heels and recycle streams. The objective of the tests was to determine whether one of these processes is causing excessive fouling of the crossflow or secondary filter. The authors conducted the tests with feed solutions containing 6.6 M sodium Salt Batch 6 simulant supernate with no MST.

From nanoparticles to fibres: effect of dispersion composition on fibre properties

Science.gov (United States)

Schirmer, Katharina S. U.; Esrafilzadeh, Dorna; Thompson, Brianna C.; Quigley, Anita F.; Kapsa, Robert M. I.; Wallace, Gordon G.

2015-06-01

A polyvinyl alcohol (PVA)-stabilized polypyrrole nanodispersion has been optimised for conductivity and processability by decreasing the quantity of PVA before and after synthesis. A reduction of PVA before synthesis leads to the formation of particles with a slight increase in dry particle diameter (51 ± 6 to 63 ± 3 nm), and conversely a reduced hydrodynamic diameter. Conductivity of the dried nanoparticle films was not measureable after a reduction of PVA prior to synthesis. Using filtration of particles after synthesis, PVA content was sufficiently reduced to achieve dried thin film conductivity of 2 S cm-1, while the electroactivity of the dispersed particles remained unchanged. The as-synthesized and PVA-reduced polypyrrole particles were successfully spun into all-nanoparticle fibres using a wet-extrusion approach without the addition of any polymer or gel matrix. Using nanoparticles as a starting material is a novel approach, which allowed the production of macro-scale fibres that consisted entirely of polypyrrole nanoparticles. Fibres made from PVA-reduced polypyrrole showed higher electroactivity compared to fibres composed of the dispersion high in PVA. The mechanical properties of the fibres were also improved by reducing the amount of PVA present, resulting in a stronger, more ductile and less brittle fibre, which could find potential application in various fields.

SU-8 hollow cantilevers for AFM cell adhesion studies

Science.gov (United States)

Martinez, Vincent; Behr, Pascal; Drechsler, Ute; Polesel-Maris, Jérôme; Potthoff, Eva; Vörös, Janos; Zambelli, Tomaso

2016-05-01

A novel fabrication method was established to produce flexible, transparent, and robust tipless hollow atomic force microscopy (AFM) cantilevers made entirely from SU-8. Channels of 3 μm thickness and several millimeters length were integrated into 12 μm thick and 40 μm wide cantilevers. Connected to a pressure controller, the devices showed high sealing performance with no leakage up to 6 bars. Changing the cantilever lengths from 100 μm to 500 μm among the same wafer allowed the targeting of various spring constants ranging from 0.5 to 80 N m-1 within a single fabrication run. These hollow polymeric AFM cantilevers were operated in the optical beam deflection configuration. To demonstrate the performance of the device, single-cell force spectroscopy experiments were performed with a single probe detaching in a serial protocol more than 100 Saccharomyces cerevisiae yeast cells from plain glass and glass coated with polydopamine while measuring adhesion forces in the sub-nanoNewton range. SU-8 now offers a new alternative to conventional silicon-based hollow cantilevers with more flexibility in terms of complex geometric design and surface chemistry modification.

SU-8 hollow cantilevers for AFM cell adhesion studies

International Nuclear Information System (INIS)

Martinez, Vincent; Behr, Pascal; Vörös, Janos; Zambelli, Tomaso; Drechsler, Ute; Polesel-Maris, Jérôme; Potthoff, Eva

2016-01-01

A novel fabrication method was established to produce flexible, transparent, and robust tipless hollow atomic force microscopy (AFM) cantilevers made entirely from SU-8. Channels of 3 μm thickness and several millimeters length were integrated into 12 μm thick and 40 μm wide cantilevers. Connected to a pressure controller, the devices showed high sealing performance with no leakage up to 6 bars. Changing the cantilever lengths from 100 μm to 500 μm among the same wafer allowed the targeting of various spring constants ranging from 0.5 to 80 N m −1 within a single fabrication run. These hollow polymeric AFM cantilevers were operated in the optical beam deflection configuration. To demonstrate the performance of the device, single-cell force spectroscopy experiments were performed with a single probe detaching in a serial protocol more than 100 Saccharomyces cerevisiae yeast cells from plain glass and glass coated with polydopamine while measuring adhesion forces in the sub-nanoNewton range. SU-8 now offers a new alternative to conventional silicon-based hollow cantilevers with more flexibility in terms of complex geometric design and surface chemistry modification. (paper)

Advanced Fibre Based Energy Storage

Science.gov (United States)

Reid, Daniel Oliver

New energy storage devices are required to enable future technologies. With the rise of wearable consumer and medical devices, a suitable flexible and wearable means of storing electrical energy is required. Fibre-based devices present a possible method of achieving this aim. Fibres are inherently more flexible than their bulk counterparts, and as such can be employed to form the electrodes of flexible batteries and capacitors. They also present a facile possibility for incorporation into many fabrics and clothes, further boosting their potential for use in wearable devices. Electrically conducting fibres were produced from a dispersion of carbon nanomaterials in a room temperature ionic liquid. Coagulation of this dispersion was achieved through manual injection into aqueous solutions of xanthan gum. The limitations of this method are highlighted by very low ultimate tensile strengths of these fibres, in the order of 3 MPa, with high variation within all of the fibres. Fibres were also produced via scrolling of bi-component films containing poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) and poly(vinyl alcohol) (PVA). Chemical treatments were employed to impart water compatibility to these fibres, and their electrochemical, physical and electrical properties were analysed. Fibres were wet spun from two PEDOT:PSS sources, in several fibre diameters. The effect of chemical treatments on the fibres were investigated and compared. Short 5 min treatment times with dimethyl sulfoxide (DMSO) on 20 mum fibres produced from Clevios PH1000 were found to produce the best overall treatment. Up to a six-fold increase in electrical conductivity resulted, reaching 800 S cm-1, with up to 40 % increase in specific capacitance and no loss of mechanical strength (55 F g-1 and 150 MPa recorded). A wet spinning system to produce PEDOT:PSS fibres containing functionalised graphenes and carbon nanotubes, as well as birnessite nanotubes was subsequently developed

DETECTORS: scintillating fibres

International Nuclear Information System (INIS)

Anon.

1994-01-01

In the continual search for improved detection techniques, new materials are continually proving profitable. A good example is scintillating plastic fibres - tiny transparent threads sometimes finer than a human hair which transmit light. The narrowness and flexibility of these fibres was a major breakthrough for endoscopy - non-invasive techniques for viewing the otherwise inaccessible in surgery or machine inspection. In a more sophisticated form, these fibres find ready application in communications technology, where the goal is to transmit information rather than electrical power, replacing conventional and unwieldy current-carrying wire conductors. In particle physics, fibres have long been used to take the tiny scintillations produced when high energy particles hit fluorescent materials and 'conduct' them to photosensitive detectors some distance away

A fully integrated continuous-time 1Hz low-pass filter with high dynamic range and low distortion

DEFF Research Database (Denmark)

Shah, Peter Jivan

1993-01-01

A first order 1Hz integrated filter needing no external components is described. It uses an on-chip capacitor of 100pF and a new differential transconductance amplifier which allows direct implementation of very small transconductances by using MOS transistors in their triode region. This further......A first order 1Hz integrated filter needing no external components is described. It uses an on-chip capacitor of 100pF and a new differential transconductance amplifier which allows direct implementation of very small transconductances by using MOS transistors in their triode region...

Adaptive Command Filtered Integrated Guidance and Control for Hypersonic Vehicle with Magnitude, Rate and Bandwidth Constraints

Directory of Open Access Journals (Sweden)

Wang Liang

2018-01-01

Full Text Available This paper proposes a novel integrated guidance and control (IGC method for hypersonic vehicle in terminal phase. Firstly, the system model is developed with a second order actuator dynamics. Then the back-stepping controller is designed hierarchically with command filters, where the first order command filters are implemented to construct the virtual control input with ideal states predicted by an adaptive estimator, and the nonlinear command filter is designed to produce magnitude, rate and bandwidth limited control surface deflection finally tracked by a terminal sliding mode controller with finite convergence time. Through a series of 6-DOF numerical simulations, it’s indicated that the proposed method successfully cancels out the large aerodynamics coefficient uncertainties and disturbances in hypersonic flight under limited control surface deflection. The contribution of this paper lies in the application and determination of nonlinear integrated design of guidance and control system for hypersonic vehicle.

Special fibres and components

DEFF Research Database (Denmark)

Bunge, C.-A.; Woyessa, Getinet; Bremer, K.

2017-01-01

In this chapter we present more specific fibre types for particular applications. Starting with the multi-core fibre, which can be used as a substitution for ordinary SI-POF transmission fibres, but with better bending losses, over the ever increasing range of micro-structured POF for diverse sen...

Mechanical processing of bast fibres: The occurrence of damage and its effect on fibre structure

DEFF Research Database (Denmark)

Hänninen, Tuomas; Thygesen, Anders; Mehmood, Shahid

2012-01-01

Currently, separation processes used for natural fibres for composite reinforcing textiles cause a significant amount of damage to the fibres. Microscopic analysis showed that industrially processed flax (Linum usitassimium L.) fibres contained significantly more defects than green or retted ones...... to heterogeneous reactivity. Analogous findings were observed in hemp (Cannabis sativa L.) fibre damaged in the laboratory under controlled conditions, emphasising the need to develop extraction and separation processes that minimise mechanical damage to the fibres....

Fundamentals of fibre-reinforced soil engineering

CERN Document Server

Shukla, Sanjay Kumar

2017-01-01

This book is intended to serve as a one-stop reference on fibre-reinforced soils. Over the past 30-35 years, the engineering behaviour of randomly distributed/oriented fibre-reinforced soil, also called simply fibre-reinforced soil, has been investigated in detail by researchers and engineers worldwide. Waste fibres (plastic waste fibres, old tyre fibres, etc.) create disposal and environmental problems. Utilization of such fibres in construction can help resolve these concerns. Research studies and some field applications have shown that the fibres can be utilized in large quantities in geotechnical and civil engineering applications in a cost-effective and environmentally friendly manner. This book covers a complete description of fibres, their effects when included within a soil or other similar materials such as the fly ash, and their field applications. It gives a detailed view of fibre-reinforced soil engineering. The book will be useful to students, professional, and researchers alike, and can also ser...

Barley fibre and wet distillers' solubles in the diet of growing cattle

Directory of Open Access Journals (Sweden)

T. ROOT

2008-12-01

Full Text Available Twenty-eight bulls were used in a 3 × 2 factorial design to study the effects of two by-products from the integrated starch-ethanol process, barley fibre and distillers' solubles, as supplements for grass silage. The animals were divided into five blocks and slaughtered when the average live weight (LW of each block reached 500 kg. The three energy supplements were barley (B, a mixture (1:1 on a dry matter (DM basis of barley and barley fibre (BF, and barley fibre (F, fed without (DS- or with (DS+ wet distillers' solubles (200 g kg-1 concentrate on DM basis. Concentrates were given at the rate of 95 g DM kg-1 LW0.6. Including barley fibre in the diet did not affect feed intake, but distillers' solubles tended to increase both silage and total DM intakes as well as amino acids absorbed in the intestine and energy intake. The protein balance in the rumen increased with the inclusion of barley fibre (P

Fun with Optical Fibres

Science.gov (United States)

Alti, Kamlesh

2017-01-01

Optical fibres play a very crucial role in today's technologies. Academic courses in optical fibres start at the undergraduate level. Nevertheless, student's curiosity towards optical fibres starts from the school level. In this paper, some fun experiments have been designed for both school and college students, which have some concrete…

Axial Compression Tests on Corroded Reinforced Concrete Columns Consolidated with Fibre Reinforced Polymers

Directory of Open Access Journals (Sweden)

Bin Ding

2017-06-01

Full Text Available Reinforced concrete structure featured by strong bearing capacity, high rigidity, good integrity, good fire resistance, and extensive applicability occupies a mainstream position in contemporary architecture. However, with the development of social economy, people need higher requirements on architectural structure; durability, especially, has been extensively researched. Because of the higher requirement on building material, ordinary reinforced concrete structure has not been able to satisfy the demand. As a result, some new materials and structures have emerged, for example, fibre reinforced polymers. Compared to steel reinforcement, fibre reinforced polymers have many advantages, such as high tensile strength, good durability, good shock absorption, low weight, and simple construction. The application of fibre reinforced polymers in architectural structure can effectively improve the durability of the concrete structure and lower the maintenance, reinforcement, and construction costs in severe environments. Based on the concepts of steel tube concrete, fibre reinforced composite material confined concrete, and fibre reinforced composite material tubed concrete, this study proposes a novel composite structure, i.e., fibre reinforced composite material and steel tube concrete composite structure. The structure was developed by pasting fibre around steel tube concrete and restraining core concrete using fibre reinforced composite material and steel tubes. The bearing capacity and ultimate deformation capacity of the structure was tested using column axial compression test.

A Micro-Computed Tomography Technique to Study the Quality of Fibre Optics Embedded in Composite Materials

Directory of Open Access Journals (Sweden)

Gabriele Chiesura

2015-05-01

Full Text Available Quality of embedment of optical fibre sensors in carbon fibre-reinforced polymers plays an important role in the resultant properties of the composite, as well as for the correct monitoring of the structure. Therefore, availability of a tool able to check the optical fibre sensor-composite interaction becomes essential. High-resolution 3D X-ray Micro-Computed Tomography, or Micro-CT, is a relatively new non-destructive inspection technique which enables investigations of the internal structure of a sample without actually compromising its integrity. In this work the feasibility of inspecting the position, the orientation and, more generally, the quality of the embedment of an optical fibre sensor in a carbon fibre reinforced laminate at unit cell level have been proven.

Machine remaining useful life prediction: An integrated adaptive neuro-fuzzy and high-order particle filtering approach

Science.gov (United States)

Chen, Chaochao; Vachtsevanos, George; Orchard, Marcos E.

2012-04-01

Machine prognosis can be considered as the generation of long-term predictions that describe the evolution in time of a fault indicator, with the purpose of estimating the remaining useful life (RUL) of a failing component/subsystem so that timely maintenance can be performed to avoid catastrophic failures. This paper proposes an integrated RUL prediction method using adaptive neuro-fuzzy inference systems (ANFIS) and high-order particle filtering, which forecasts the time evolution of the fault indicator and estimates the probability density function (pdf) of RUL. The ANFIS is trained and integrated in a high-order particle filter as a model describing the fault progression. The high-order particle filter is used to estimate the current state and carry out p-step-ahead predictions via a set of particles. These predictions are used to estimate the RUL pdf. The performance of the proposed method is evaluated via the real-world data from a seeded fault test for a UH-60 helicopter planetary gear plate. The results demonstrate that it outperforms both the conventional ANFIS predictor and the particle-filter-based predictor where the fault growth model is a first-order model that is trained via the ANFIS.

Long-period fiber-brating-based filter for generation of picosecond and subpicosecond transform-limited flat-top pulses

Czech Academy of Sciences Publication Activity Database

Slavík, Radan; Park, Y.; Azana, J.

2008-01-01

Roč. 20, č. 10 (2008), s. 806-808 ISSN 1041-1135 R&D Projects: GA AV ČR(CZ) KJB200670601; GA ČR(CZ) GA102/07/0999 Institutional research plan: CEZ:AV0Z20670512 Keywords : optical fibre filter s * passive filter s * optical pulse shaping Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.173, year: 2008

Method for the production of fabricated hollow microspheroids

Science.gov (United States)

Wickramanayake, Shan; Luebke, David R.

2015-06-09

The method relates to the fabrication of a polymer microspheres comprised of an asymmetric layer surrounding a hollow interior. The fabricated hollow microsphere is generated from a nascent hollow microsphere comprised of an inner core of core fluid surrounded by a dope layer of polymer dope, where the thickness of the dope layer is at least 10% and less than 50% of the diameter of the inner core. The nascent hollow microsphere is exposed to a gaseous environment, generating a vitrified hollow microsphere, which is subsequently immersed in a coagulation bath. Solvent exchange produces a fabricated hollow microsphere comprised of a densified outer skin surrounding a macroporous inner layer, which surrounds a hollow interior. In an embodiment, the polymer is a polyimide or a polyamide-imide, and the non-solvent in the core fluid and the coagulation bath is water. The fabricated hollow microspheres are particularly suited as solvent supports for gas separation processes.

From nanoparticles to fibres: effect of dispersion composition on fibre properties

Energy Technology Data Exchange (ETDEWEB)

Schirmer, Katharina S. U.; Esrafilzadeh, Dorna; Thompson, Brianna C.; Quigley, Anita F.; Kapsa, Robert M. I.; Wallace, Gordon G., E-mail: gwallace@uow.edu.au [University of Wollongong, ARC Centre for Electromaterials Science and Intelligent Polymer Research Institute (Australia)

2015-06-15

A polyvinyl alcohol (PVA)-stabilized polypyrrole nanodispersion has been optimised for conductivity and processability by decreasing the quantity of PVA before and after synthesis. A reduction of PVA before synthesis leads to the formation of particles with a slight increase in dry particle diameter (51 ± 6 to 63 ± 3 nm), and conversely a reduced hydrodynamic diameter. Conductivity of the dried nanoparticle films was not measureable after a reduction of PVA prior to synthesis. Using filtration of particles after synthesis, PVA content was sufficiently reduced to achieve dried thin film conductivity of 2 S cm{sup −1}, while the electroactivity of the dispersed particles remained unchanged. The as-synthesized and PVA-reduced polypyrrole particles were successfully spun into all-nanoparticle fibres using a wet-extrusion approach without the addition of any polymer or gel matrix. Using nanoparticles as a starting material is a novel approach, which allowed the production of macro-scale fibres that consisted entirely of polypyrrole nanoparticles. Fibres made from PVA-reduced polypyrrole showed higher electroactivity compared to fibres composed of the dispersion high in PVA. The mechanical properties of the fibres were also improved by reducing the amount of PVA present, resulting in a stronger, more ductile and less brittle fibre, which could find potential application in various fields.

From nanoparticles to fibres: effect of dispersion composition on fibre properties

International Nuclear Information System (INIS)

Schirmer, Katharina S. U.; Esrafilzadeh, Dorna; Thompson, Brianna C.; Quigley, Anita F.; Kapsa, Robert M. I.; Wallace, Gordon G.

2015-01-01

A polyvinyl alcohol (PVA)-stabilized polypyrrole nanodispersion has been optimised for conductivity and processability by decreasing the quantity of PVA before and after synthesis. A reduction of PVA before synthesis leads to the formation of particles with a slight increase in dry particle diameter (51 ± 6 to 63 ± 3 nm), and conversely a reduced hydrodynamic diameter. Conductivity of the dried nanoparticle films was not measureable after a reduction of PVA prior to synthesis. Using filtration of particles after synthesis, PVA content was sufficiently reduced to achieve dried thin film conductivity of 2 S cm −1 , while the electroactivity of the dispersed particles remained unchanged. The as-synthesized and PVA-reduced polypyrrole particles were successfully spun into all-nanoparticle fibres using a wet-extrusion approach without the addition of any polymer or gel matrix. Using nanoparticles as a starting material is a novel approach, which allowed the production of macro-scale fibres that consisted entirely of polypyrrole nanoparticles. Fibres made from PVA-reduced polypyrrole showed higher electroactivity compared to fibres composed of the dispersion high in PVA. The mechanical properties of the fibres were also improved by reducing the amount of PVA present, resulting in a stronger, more ductile and less brittle fibre, which could find potential application in various fields

Fibre Bragg grating and no-core fibre sensors

CERN Document Server

Daud, Suzairi

2018-01-01

This book focuses on the development and set-up of fibre Bragg grating (FBG) and no-core fibre (NCF) sensors. It discusses the properties of the sensors and modelling of the resulting devices, which include electronic, optoelectronic, photovoltaic, and spintronic devices. In addition to providing detailed explanations of the properties of FBG and NCF sensors, it features a wealth of instructive illustrations and tables, helping to visualize the respective devices’ functions.

Machining of Fibre Reinforced Plastic Composite Materials

Science.gov (United States)

2018-01-01

Fibre reinforced plastic composite materials are difficult to machine because of the anisotropy and inhomogeneity characterizing their microstructure and the abrasiveness of their reinforcement components. During machining, very rapid cutting tool wear development is experienced, and surface integrity damage is often produced in the machined parts. An accurate selection of the proper tool and machining conditions is therefore required, taking into account that the phenomena responsible for material removal in cutting of fibre reinforced plastic composite materials are fundamentally different from those of conventional metals and their alloys. To date, composite materials are increasingly used in several manufacturing sectors, such as the aerospace and automotive industry, and several research efforts have been spent to improve their machining processes. In the present review, the key issues that are concerning the machining of fibre reinforced plastic composite materials are discussed with reference to the main recent research works in the field, while considering both conventional and unconventional machining processes and reporting the more recent research achievements. For the different machining processes, the main results characterizing the recent research works and the trends for process developments are presented. PMID:29562635

Machining of Fibre Reinforced Plastic Composite Materials

Directory of Open Access Journals (Sweden)

Alessandra Caggiano

2018-03-01

Full Text Available Fibre reinforced plastic composite materials are difficult to machine because of the anisotropy and inhomogeneity characterizing their microstructure and the abrasiveness of their reinforcement components. During machining, very rapid cutting tool wear development is experienced, and surface integrity damage is often produced in the machined parts. An accurate selection of the proper tool and machining conditions is therefore required, taking into account that the phenomena responsible for material removal in cutting of fibre reinforced plastic composite materials are fundamentally different from those of conventional metals and their alloys. To date, composite materials are increasingly used in several manufacturing sectors, such as the aerospace and automotive industry, and several research efforts have been spent to improve their machining processes. In the present review, the key issues that are concerning the machining of fibre reinforced plastic composite materials are discussed with reference to the main recent research works in the field, while considering both conventional and unconventional machining processes and reporting the more recent research achievements. For the different machining processes, the main results characterizing the recent research works and the trends for process developments are presented.

Sputter etching of polymer fibres

International Nuclear Information System (INIS)

Carter, G.; Hill, A.E.; Nobes, M.J.; Jeffries, R.; Simmens, S.C.

1979-01-01

Fibres of polyamide, polyester and an aromatic polyamide (Kevlar) have been subjected to Ar + ion bombardment erosion in an ion accelerator or an rf discharge system. In the case of the former two polymers, cones are observed to develop upon the fibre surface and these are associated with etch protection resulting from the presence of particles of titanium dioxide pigment. This effect is absent in the third, unpigmented, fibre. In all cases ripple structures with a habit transverse to the fibre axes and of wavelength of approximately 1000 Angstrom are gradually developed during ion bombardment. It is suggested that this morphology results from an underlying periodicity of the fibre structure either inherent in the fibre structure or induced by the irradiation. (author)

Complex Hollow Nanostructures: Synthesis and Energy-Related Applications.

Science.gov (United States)

Yu, Le; Hu, Han; Wu, Hao Bin; Lou, Xiong Wen David

2017-04-01

Hollow nanostructures offer promising potential for advanced energy storage and conversion applications. In the past decade, considerable research efforts have been devoted to the design and synthesis of hollow nanostructures with high complexity by manipulating their geometric morphology, chemical composition, and building block and interior architecture to boost their electrochemical performance, fulfilling the increasing global demand for renewable and sustainable energy sources. In this Review, we present a comprehensive overview of the synthesis and energy-related applications of complex hollow nanostructures. After a brief classification, the design and synthesis of complex hollow nanostructures are described in detail, which include hierarchical hollow spheres, hierarchical tubular structures, hollow polyhedra, and multi-shelled hollow structures, as well as their hybrids with nanocarbon materials. Thereafter, we discuss their niche applications as electrode materials for lithium-ion batteries and hybrid supercapacitors, sulfur hosts for lithium-sulfur batteries, and electrocatalysts for oxygen- and hydrogen-involving energy conversion reactions. The potential superiorities of complex hollow nanostructures for these applications are particularly highlighted. Finally, we conclude this Review with urgent challenges and further research directions of complex hollow nanostructures for energy-related applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A model for the anisotropic response of fibrous soft tissues using six discrete fibre bundles

KAUST Repository

Flynn, Cormac

2011-06-30

The development of constitutive models of fibrous soft-tissues is a challenging problem. Many consider the tissue to be a collection of fibres with a continuous distribution function representing their orientations. A discrete fibre model is presented consisting of six weighted fibre-bundles. Each bundle is oriented such that it passes through opposing vertices of a regular icosahedron. A novel aspect is the use of simple analytical distribution functions to simulate undulated collagen fibres. This approach yields closed-form analytical expressions for the strain energy of the collagen fibre-bundle that avoids the sometimes costly numerical integration of some statistical distribution functions. The elastin fibres are characterized by a modified neo-Hookean type strain energy function which does not allow for fibre compression. The model accurately simulates biaxial stretching of rabbit-skin (error-of-fit 8.7), uniaxial stretching of pig-skin (error-of-fit 7.6), equibiaxial loading of aortic valve cusp (error-of-fit 0.8), and simple shear of rat septal myocardium (error-of-fit 8.9). It compares favourably with previous soft-tissue models and alternative methods of representing undulated collagen fibres. Predicted collagen fibre stiffnesses range from 8.0thinspaceMPa to 930MPa. Elastin fibre stiffnesses range from 2.0 kPa to 154.4 kPa. © 2011 John Wiley & Sons, Ltd.

A model for the anisotropic response of fibrous soft tissues using six discrete fibre bundles

KAUST Repository

Flynn, Cormac; Rubin, M. B.; Nielsen, Poul

2011-01-01

The development of constitutive models of fibrous soft-tissues is a challenging problem. Many consider the tissue to be a collection of fibres with a continuous distribution function representing their orientations. A discrete fibre model is presented consisting of six weighted fibre-bundles. Each bundle is oriented such that it passes through opposing vertices of a regular icosahedron. A novel aspect is the use of simple analytical distribution functions to simulate undulated collagen fibres. This approach yields closed-form analytical expressions for the strain energy of the collagen fibre-bundle that avoids the sometimes costly numerical integration of some statistical distribution functions. The elastin fibres are characterized by a modified neo-Hookean type strain energy function which does not allow for fibre compression. The model accurately simulates biaxial stretching of rabbit-skin (error-of-fit 8.7), uniaxial stretching of pig-skin (error-of-fit 7.6), equibiaxial loading of aortic valve cusp (error-of-fit 0.8), and simple shear of rat septal myocardium (error-of-fit 8.9). It compares favourably with previous soft-tissue models and alternative methods of representing undulated collagen fibres. Predicted collagen fibre stiffnesses range from 8.0thinspaceMPa to 930MPa. Elastin fibre stiffnesses range from 2.0 kPa to 154.4 kPa. © 2011 John Wiley & Sons, Ltd.

Single-mode optical fibres

CERN Document Server

Cancellieri, G

1991-01-01

This book describes signal propagation in single-mode optical fibres for telecommunication applications. Such description is based on the analysis of field propagation, considering waveguide properties and also some of the particular characteristics of the material fibre. The book covers such recent advances as, coherent transmissions; optical amplification; MIR fibres; polarization maintaining; polarization diversity and photon counting.

Airborne asbestos fibre levels in buildings: a summary of UK measurements.

Science.gov (United States)

Burdett, G J; Jaffrey, S A; Rood, A P

1989-01-01

The UK Health and Safety Executive, in conjunction with the Department of the Environment, has carried out a number of surveys of airborne asbestos fibre concentrations in buildings. All samples have been collected on membrane filters and analysed by analytical transmission electron microscopy. Four categories of buildings under normal occupation have been investigated; non-domestic buildings containing sprayed or trowelled asbestos, domestic buildings containing sprayed asbestos or asbestos plaster, buildings with warm air heaters containing asbestos and buildings without asbestos materials. A number of buildings have also been surveyed during and after the removal of asbestos materials. The choice of measurement indices and analytical procedures is reviewed, before measurements are compared in terms of the concentration of asbestos fibres greater than 5 microns long. The decision whether to remove asbestos from occupied buildings is discussed with reference to the associated cost and risk. In the present survey, management of undamaged asbestos appeared preferable to large-scale removal.

Crack Detection in Fibre Reinforced Plastic Structures Using Embedded Fibre Bragg Grating Sensors: Theory, Model Development and Experimental Validation

DEFF Research Database (Denmark)

Pereira, Gilmar Ferreira; Mikkelsen, Lars Pilgaard; McGugan, Malcolm

2015-01-01

properties. When applying this concept to different structures, sensor systems and damage types, a combination of damage mechanics, monitoring technology, and modelling is required. The primary objective of this article is to demonstrate such a combination. This article is divided in three main topics......: the damage mechanism (delamination of FRP), the structural health monitoring technology (fibre Bragg gratings to detect delamination), and the finite element method model of the structure that incorporates these concepts into a final and integrated damage-monitoring concept. A novel method for assessing...... by the end-user. Conjointly, a novel model for sensor output prediction (virtual sensor) was developed using this FBG sensor crack monitoring concept and implemented in a finite element method code. The monitoring method was demonstrated and validated using glass fibre double cantilever beam specimens...

Hollow fiber: a biophotonic implant for live cells

Science.gov (United States)

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.

Fibre Bragg Grating and Long Period Grating Sensors in Polymer Optical Fibres

DEFF Research Database (Denmark)

Bundalo, Ivan-Lazar

mechanisms in polymer fibres using a CO2 laser. One is etching and the other one is perturbation of the microstructured region. After inscription of LPGs, the concept of a biocompatible distributed medical endoscope is presented, where an all-plastic LPG based device is produced. A transducer pod is made...... of applications and pushing the limits. The first part of the work focuses on the fabrication of FBGs in polymer optical fibres. FBGs are a periodic perturbation of the refractive index of the optical fibre core which act as a wavelength specific reflector. The fibres used are made of Polymethyl methacrylate....... In this system a high power CO2 laser is used for the inscription. An LPG is also a periodic perturbation of the guided core mode in fibre, but unlike FBG which reflects the core mode, the LPG couples the core mode to a cladding mode outside the core. We have shown that the LPG grating can be formed through two...

Fibre Concrete 2017

Science.gov (United States)

2017-09-01

9th international conference on fibre reinforced concretes (FRC), textile reinforced concretes (TRC) and ultra-high performance concretes (UHPC) Preface The Fibre Concrete Conference series is held biennially to provide a platform to share knowledge on fibre reinforced concretes, textile concretes and ultra-high performance concretes regarding material properties and behaviour, technology procedures, topics of long-term behaviour, creep, durability; sustainable aspects of concrete including utilisation of waste materials in concrete production and recycling of concrete. The tradition of Fibre Concrete Conferences started in eighties of the last century. Nowadays the conference is organized by the Department of Concrete and Masonry Structures of the Czech Technical University in Prague, Faculty of Civil Engineering. The 9th International Conference Fibre Concrete 2017 had 109 participants from 27 countries all over the world. 55 papers were presented including keynote lectures of Professor Bažant, Professor Bartoš and Dr. Broukalová. The conference program covered wide range of topics from scientific research to practical applications. The presented contributions related to performance and behaviour of cement based composites, their long-term behaviour and durability, sustainable aspects, advanced analyses of structures from these composites and successful applications. This conference was organized also to honour Professor Zděnek P. Bažant on the occasion of his jubilee and to appreciate his merits and discoveries in the field of fibre reinforced composites, structural mechanics and engineering.

Substrate Integrated Waveguide Cross-Coupling Filter with Multilayer Hexagonal Cavity

Directory of Open Access Journals (Sweden)

B. Wu

2013-01-01

Full Text Available Hexagonal cavities and their applications to multilayer substrate integrated waveguide (SIW filters are presented. The hexagonal SIW cavity which can combine flexibility of rectangular one and performance of circular one is convenient for bandpass filter’s design. Three types of experimental configuration with the same central frequency of 10 GHz and bandwidth of 6%, including three-order and four-order cross-coupling topologies, are constructed and fabricated based on low temperature cofired ceramic (LTCC technology. Both theoretical and experimental results are presented.

Miniaturized dielectric waveguide filters

OpenAIRE

Sandhu, MY; Hunter, IC

2016-01-01

Design techniques for a new class of integrated monolithic high-permittivity ceramic waveguide filters are presented. These filters enable a size reduction of 50% compared to air-filled transverse electromagnetic filters with the same unloaded Q-factor. Designs for Chebyshev and asymmetric generalised Chebyshev filter and a diplexer are presented with experimental results for an 1800 MHz Chebyshev filter and a 1700 MHz generalised Chebyshev filter showing excellent agreement with theory.

Characterisation of Flax Fibres and Flax Fibre Composites. Being cellulose based sources of materials

DEFF Research Database (Denmark)

Aslan, Mustafa

-melting temperature polyethylene terephthalate (LPET) filaments were aligned in assemblies of different fibre weight fractions in the range 0.24 to 0.83 to manufacture unidirectional composites using two different consolidation pressures of 1.67 and 4.10 MPa. The maximum attainable fibre volume fraction is found...... to be 47% for the low pressure composites, whereas it is found to be 60% for the high pressure composites. The stiffness of the flax fibre/LPET composites is measured to be in the range 16 to 33 GPa depending on the volumetric composition of the composites. The high pressure composites are found to have...... a similar microstructure at low fibre weight fractions. However, when the fibre content is increased, a difference in porosity content can be observed from the composite cross sections. The nominal tensile strength of the unidirectional flax fibre/LPET composites is measured in the range 180 to 340 MPa...

Development of SERS active fibre sensors

International Nuclear Information System (INIS)

Polwart, Ewan

2002-01-01

Surface-enhanced Raman scattering (SERS) is sensitive and selective and when coupled with fibre-optics could potentially produce an effective chemical sensing system. This thesis concerns the development of a single-fibre-based sensor, with an integral SERS-active substrate. A number of different methods for the manufacture of SERS-active surfaces on glass substrates were investigated and compared. The immobilisation of metal nanoparticles on glass functionalised with (3-aminopropyl)trimethoxysilane emerged as a suitable approach for the production of sensors. Substrates prepared by this approach were characterised using UV-visible spectroscopy, electron microscopy and Raman mapping. It was found that exposure of substrates to laser radiation led to a decrease in the signal recorded from adsorbed analytes. This speed of the decrease was shown to depend on the analyte, and the exciting wavelength and power. SERS-active fibre sensors were produced by immobilisation of silver nanoparticles at the distal end of a (3-aminopropyl)trimethoxysilane-derivatised optical fibre. These sensors were used to obtain spectra with good signal to noise ratios from 4-(benzotriazol-5-ylazo)-3,5-dimethoxyphenylamine and crystal violet. Sensing of dyes in effluent was also investigated. The development of sensors for the measurement of pH, by treating the SERS-active fibre tip with pH sensitive dyes is also described. Spectral changes were observed with these sensors as a response to the pH. Partial least squares regression was used to produce linear calibration models for the pH range 5-11 from which it was possible to predict the pH with an accuracy of ∼0.2 pH units. Some of the limitations of these sensors were explored. The feasibility of using these sensors for measurement of oxygen and thiols, was investigated. The measurement of oxygen using methylene blue as a transducer was demonstrated. Two transduction methodologies--reactions with iron porphyrins and pyrrole-2,5-diones

Hollow bunches production

CERN Document Server

Hancock, S

2017-01-01

Hollow bunches address the issue of high-brightnessbeams suffering from transverse emittance growth in a strongspace charge regime. During the Proton Synchrotron (PS)injection plateau, the negative space charge tune shift canpush the beam onto theQy=6integer resonance. Modify-ing the longitudinal bunch profile in order to reduce the peakline charge density alleviates the detrimental impact of spacecharge. To this end we first produce longitudinally hollowphase space distributions in the PS Booster by exciting aparametric resonance with the phase loop feedback system.These inherently flat bunches are then transferred to the PS,where the beam becomes less prone to the emittance growthcaused by the integer resonance.During the late 2016 machine development sessions inthe PS Booster we profited from solved issues from 2015and managed to reliably extract hollow bunches of1.3eVsmatched longitudinal area. Furthermore, first results to cre-ate hollow bunches with larger longitudinal emittances to-wards the LHC Inject...

A cast partial obturator with hollow occlusal shim and semi-precision attachment

Directory of Open Access Journals (Sweden)

Mukesh Kumar Singhal

2018-01-01

Full Text Available A maxillofacial patient's quality of life is distorted and social integration becomes difficult. An obturator is a maxillofacial prosthesis used to close a congenital or acquired tissue defect, primarily of the hard palate and/or contiguous alveolar/soft-tissue structures. Subsequently, it restores the esthetics, speech, and function. The present clinical report aimed for the prosthetic rehabilitation of a maxillectomy defect by the incorporation of a semi-precision attachment as PRECI-SAGIX – male part of 2.2 mm on fixed partial denture (#22 and #23 teeth and matrix – plastic female part of size 2.2 mm and height 4.2 mm of yellow on cast partial in polymer base. It aids in the retention of a hollow lightweight obturator. The technique also described the method to make a bulbless obturator with a hollow self-cured acrylic resin occlusal shim. A patient is quite satisfied with bulb less, lightweight cast partial and hollow shim palatal obturator.

Analysis of glass fibre sizing

DEFF Research Database (Denmark)

Petersen, Helga Nørgaard; Kusano, Yukihiro; Brøndsted, Povl

2014-01-01

Glass fibre reinforced polymer composites are widely used for industrial and engineering applications which include construction, aerospace, automotive and wind energy industry. During the manufacturing glass fibres, they are surface-treated with an aqueous solution. This process and the treated...... surfaces are called sizing. The sizing influences the properties of the interface between fibres and a matrix, and subsequently affects mechanical properties of composites. In this work the sizing of commercially available glass fibres was analysed so as to study the composition and chemical structures....... Soxhlet extraction was used to extract components of the sizing from the glass fibres. The glass fibres, their extracts and coated glass plates were analysed by Thermo-Gravimetric Analysis combined with a mass spectrometer (TGA-MS), and Attenuated Total Reflectance Fourier Transform Infrared (ATR...

Muscle fibre capillarization is a critical factor in muscle fibre hypertrophy during resistance exercise training in older men.

Science.gov (United States)

Snijders, Tim; Nederveen, Joshua P; Joanisse, Sophie; Leenders, Marika; Verdijk, Lex B; van Loon, Luc J C; Parise, Gianni

2017-04-01

Adequate muscle fibre perfusion is critical for the maintenance of muscle mass; it is essential in the rapid delivery of oxygen, nutrients and growth factors to the muscle, stimulating muscle fibre growth. Muscle fibre capillarization is known to decrease substantially with advancing age. However, whether (relative) low muscle fibre capillarization negatively impacts the muscle hypertrophic response following resistance exercise training in older adults is unknown. Twenty-two healthy older men (71 ± 1 years) performed 24 weeks of progressive resistance type exercise training. To assess the change in muscle fibre characteristics, percutaneous biopsies from the vastus lateralis muscle were taken before and following 12 and 24 weeks of the intervention programme. A comparison was made between participants who had a relatively low type II muscle fibre capillary-to-fibre perimeter exchange index (CFPE; LOW group) and high type II muscle fibre CFPE (HIGH group) at baseline. Type I and type II muscle fibre size, satellite cell, capillary content and distance between satellite cells to the nearest capillary were determined by immunohistochemistry. Overall, type II muscle fibre size (from 5150 ± 234 to 6719 ± 446 µm 2 , P muscle fibre, P muscle fibre capillarization, whereas muscle fibre size (from 5170 ± 390 to 7133 ± 314 µm 2 , P muscle fibre, P muscle fibre capillarization were observed in response to 12 and 24 weeks of resistance exercise training in both the LOW and HIGH group. Type II muscle fibre capillarization at baseline may be a critical factor for allowing muscle fibre hypertrophy to occur during prolonged resistance exercise training in older men. © 2016 The Authors. Journal of Cachexia, Sarcopenia and Muscle published by John Wiley & Sons Ltd on behalf of the Society on Sarcopenia, Cachexia and Wasting Disorders.

Slice image pretreatment for cone-beam computed tomography based on adaptive filter

International Nuclear Information System (INIS)

Huang Kuidong; Zhang Dinghua; Jin Yanfang

2009-01-01

According to the noise properties and the serial slice image characteristics in Cone-Beam Computed Tomography (CBCT) system, a slice image pretreatment for CBCT based on adaptive filter was proposed. The judging criterion for the noise is established firstly. All pixels are classified into two classes: adaptive center weighted modified trimmed mean (ACWMTM) filter is used for the pixels corrupted by Gauss noise and adaptive median (AM) filter is used for the pixels corrupted by impulse noise. In ACWMTM filtering algorithm, the estimated Gauss noise standard deviation in the current slice image with offset window is replaced by the estimated standard deviation in the adjacent slice image to the current with the corresponding window, so the filtering accuracy of the serial images is improved. The pretreatment experiment on CBCT slice images of wax model of hollow turbine blade shows that the method makes a good performance both on eliminating noises and on protecting details. (authors)

Tightly coupled low cost 3D RISS/GPS integration using a mixture particle filter for vehicular navigation.

Science.gov (United States)

Georgy, Jacques; Noureldin, Aboelmagd

2011-01-01

Satellite navigation systems such as the global positioning system (GPS) are currently the most common technique used for land vehicle positioning. However, in GPS-denied environments, there is an interruption in the positioning information. Low-cost micro-electro mechanical system (MEMS)-based inertial sensors can be integrated with GPS and enhance the performance in denied GPS environments. The traditional technique for this integration problem is Kalman filtering (KF). Due to the inherent errors of low-cost MEMS inertial sensors and their large stochastic drifts, KF, with its linearized models, has limited capabilities in providing accurate positioning. Particle filtering (PF) was recently suggested as a nonlinear filtering technique to accommodate for arbitrary inertial sensor characteristics, motion dynamics and noise distributions. An enhanced version of PF called the Mixture PF is utilized in this study to perform tightly coupled integration of a three dimensional (3D) reduced inertial sensors system (RISS) with GPS. In this work, the RISS consists of one single-axis gyroscope and a two-axis accelerometer used together with the vehicle's odometer to obtain 3D navigation states. These sensors are then integrated with GPS in a tightly coupled scheme. In loosely-coupled integration, at least four satellites are needed to provide acceptable GPS position and velocity updates for the integration filter. The advantage of the tightly-coupled integration is that it can provide GPS measurement update(s) even when the number of visible satellites is three or lower, thereby improving the operation of the navigation system in environments with partial blockages by providing continuous aiding to the inertial sensors even during limited GPS satellite availability. To effectively exploit the capabilities of PF, advanced modeling for the stochastic drift of the vertically aligned gyroscope is used. In order to benefit from measurement updates for such drift, which are

Tightly Coupled Low Cost 3D RISS/GPS Integration Using a Mixture Particle Filter for Vehicular Navigation

Directory of Open Access Journals (Sweden)

Jacques Georgy

2011-04-01

Full Text Available Satellite navigation systems such as the global positioning system (GPS are currently the most common technique used for land vehicle positioning. However, in GPS-denied environments, there is an interruption in the positioning information. Low-cost micro-electro mechanical system (MEMS-based inertial sensors can be integrated with GPS and enhance the performance in denied GPS environments. The traditional technique for this integration problem is Kalman filtering (KF. Due to the inherent errors of low-cost MEMS inertial sensors and their large stochastic drifts, KF, with its linearized models, has limited capabilities in providing accurate positioning. Particle filtering (PF was recently suggested as a nonlinear filtering technique to accommodate for arbitrary inertial sensor characteristics, motion dynamics and noise distributions. An enhanced version of PF called the Mixture PF is utilized in this study to perform tightly coupled integration of a three dimensional (3D reduced inertial sensors system (RISS with GPS. In this work, the RISS consists of one single-axis gyroscope and a two-axis accelerometer used together with the vehicle’s odometer to obtain 3D navigation states. These sensors are then integrated with GPS in a tightly coupled scheme. In loosely-coupled integration, at least four satellites are needed to provide acceptable GPS position and velocity updates for the integration filter. The advantage of the tightly-coupled integration is that it can provide GPS measurement update(s even when the number of visible satellites is three or lower, thereby improving the operation of the navigation system in environments with partial blockages by providing continuous aiding to the inertial sensors even during limited GPS satellite availability. To effectively exploit the capabilities of PF, advanced modeling for the stochastic drift of the vertically aligned gyroscope is used. In order to benefit from measurement updates for such drift

A rapid excitation-emission matrix fluorometer utilizing supercontinuum white light and acousto-optic tunable filters

Energy Technology Data Exchange (ETDEWEB)

Wang, Wenbo [Imaging Unit, Integrative Oncology Department, BC Cancer Agency Research Center, 675 West 10th Avenue, Vancouver, British Columbia V5Z 1L3 (Canada); Department of Dermatology and Skin Science, University of British Columbia, 835 West 10th Avenue, Vancouver, British Columbia V5Z 4E8 (Canada); Department of Biomedical Engineering, University of British Columbia, KAIS 5500, 2332 Main Mall, Vancouver, British Columbia V6T 1Z4 (Canada); Wu, Zhenguo; Zhao, Jianhua; Lui, Harvey; Zeng, Haishan, E-mail: hzeng@bccrc.ca [Imaging Unit, Integrative Oncology Department, BC Cancer Agency Research Center, 675 West 10th Avenue, Vancouver, British Columbia V5Z 1L3 (Canada); Department of Dermatology and Skin Science, University of British Columbia, 835 West 10th Avenue, Vancouver, British Columbia V5Z 4E8 (Canada)

2016-06-15

Scanning speed and coupling efficiency of excitation light to optic fibres are two major technical challenges that limit the potential of fluorescence excitation-emission matrix (EEM) spectrometer for on-line applications and in vivo studies. In this paper, a novel EEM system, utilizing a supercontinuum white light source and acousto-optic tunable filters (AOTFs), was introduced and evaluated. The supercontinuum white light, generated by pumping a nonlinear photonic crystal fiber with an 800 nm femtosecond laser, was efficiently coupled into a bifurcated optic fiber bundle. High speed EEM spectral scanning was achieved using AOTFs both for selecting excitation wavelength and scanning emission spectra. Using calibration lamps (neon and mercury argon), wavelength deviations were determined to vary from 0.18 nm to −0.70 nm within the spectral range of 500–850 nm. Spectral bandwidth for filtered excitation light broadened by twofold compared to that measured with monochromatic light between 650 nm and 750 nm. The EEM spectra for methanol solutions of laser dyes were successfully acquired with this rapid fluorometer using an integration time of 5 s.

A rapid excitation-emission matrix fluorometer utilizing supercontinuum white light and acousto-optic tunable filters

International Nuclear Information System (INIS)

Wang, Wenbo; Wu, Zhenguo; Zhao, Jianhua; Lui, Harvey; Zeng, Haishan

2016-01-01

Scanning speed and coupling efficiency of excitation light to optic fibres are two major technical challenges that limit the potential of fluorescence excitation-emission matrix (EEM) spectrometer for on-line applications and in vivo studies. In this paper, a novel EEM system, utilizing a supercontinuum white light source and acousto-optic tunable filters (AOTFs), was introduced and evaluated. The supercontinuum white light, generated by pumping a nonlinear photonic crystal fiber with an 800 nm femtosecond laser, was efficiently coupled into a bifurcated optic fiber bundle. High speed EEM spectral scanning was achieved using AOTFs both for selecting excitation wavelength and scanning emission spectra. Using calibration lamps (neon and mercury argon), wavelength deviations were determined to vary from 0.18 nm to −0.70 nm within the spectral range of 500–850 nm. Spectral bandwidth for filtered excitation light broadened by twofold compared to that measured with monochromatic light between 650 nm and 750 nm. The EEM spectra for methanol solutions of laser dyes were successfully acquired with this rapid fluorometer using an integration time of 5 s.

The development of thermoplastic fibre based reinforcements for the rotational moulding process

Science.gov (United States)

Alemán, D. N. Castellanos; McCourt, M.; Kearns, M. P.; Martin, P. J.; Butterfield, J.

2018-05-01

Rotational moulding is a method used to produce hollow plastic parts through the heating, melting and cooling of polymer powder within a metal mould. A wide range of products are made using this process, such as fluid containment tanks, boats, light weight vehicle bodies and marine buoys. Rotomoulded composites using thermoplastic fibres are of increasing interest to the industry, as they have the potential to significantly improve impact strength, whilst reducing part weight, resulting in a structure that is 100% recyclable compared to a traditional composite. A series of self-reinforced thermoplastic weaves can be used to produce a number of composite structures using the rotational moulding process. This work outlines the improvements obtained from the range of rotomoulded composites structures, as well as preforms that could be used in future rotational moulding work. Characteristics of self-reinforced materials were exploited with the aim of increasing the mechanical properties, preserving the weaves and increasing the nature of the material adhesion. Addition of the fabrics in the cooling stage was shown to be of great interest as this avoided exposure of the material to the peak temperature, which may affect the integrity of the fabric. Placing the weave during cooling was useful as the material could receive the maximum amount of tensile force during the impact test. A total of nine diverse types of compounds were manufactured and tested, with seven of the impact tests showing an increase in strength greater than 50%.

ELASTICITY of SHORT FIBRE REINFORCED POLYAMIDE: MORPHOLOGICAL AND NUMERICAl ANALYSIS OF FIBRE ORIENTATION EFFECTS

Directory of Open Access Journals (Sweden)

Francesca Cosmi

2010-10-01

Full Text Available The fatigue behaviour of injection moulded short fibre reinforced polymers depends upon fibre orientation, as shown in experiments conducted with notched specimens injected through different injection gates. The different fatigue behaviour is mainly related to the different local elastic properties, as determined by the different fibre orientation patterns, resulting into different strain distributions. In order to quantify the relationship between fibre orientation and elastic constants, the Cell Method was applied to volumes extracted from the specimens, reconstructed by micro-tomography.

Method to fabricate hollow microneedle arrays

Energy Technology Data Exchange (ETDEWEB)

Kravitz, Stanley H [Placitas, NM; Ingersoll, David [Albuquerque, NM; Schmidt, Carrie [Los Lunas, NM; Flemming, Jeb [Albuquerque, NM

2006-11-07

An inexpensive and rapid method for fabricating arrays of hollow microneedles uses a photoetchable glass. Furthermore, the glass hollow microneedle array can be used to form a negative mold for replicating microneedles in biocompatible polymers or metals. These microneedle arrays can be used to extract fluids from plants or animals. Glucose transport through these hollow microneedles arrays has been found to be orders of magnitude more rapid than natural diffusion.

Development of fibre reinforced concrete overpacks in France

International Nuclear Information System (INIS)

Boudry, J.C.; Pech, R.

1991-01-01

Radioactive waste conditioning is a major step in the processes implemented in nuclear installations. The objective is to contain the radioactive materials in nuclear waste as satisfactory as possible for man and the environment contained ensuring containment integrity having to be guaranteed over very long periods of time. Medium-level (ML) and even very low-level (LL) waste is no exception to this rule. Cogema thus conducted research for many years and developed a novel process to condition nuclear waste in containers reinforced with metal fibres, called fibre concrete containers. This process, welcomed by the French Safety Authorities and ANDRA, the French Radioactive Waste Management Agency, currently appears to be the best way to condition low and medium-level solid waste. (author)

Evidence of fire resistance of hollow-core slabs

DEFF Research Database (Denmark)

Hertz, Kristian Dahl; Sørensen, Lars Schiøtt; Giuliani, Luisa

is therefore going on in the Netherlands about the fire resistance of hollow-core slabs. In 2014 the producers of hollow-core slabs have published a report of a project called Holcofire containing a collection of 162 fire tests on hollow-core slabs giving for the first time an overview of the fire tests made....... The present paper analyses the evidence now available for assessment of the fire resistance of extruded hollow-core slabs. The 162 fire tests from the Holcofire report are compared against the requirements for testing from the product standard for hollow-core slabs EN1168 and knowledge about the possible......Hollow-core slabs have during the past 50 years comprised a variety of different structures with different cross-sections and reinforcement. At present the extruded hollow-core slabs without cross-reinforcement in the bottom flange and usually round or oval longitudinal channels (holes...

Multisensor Distributed Track Fusion AlgorithmBased on Strong Tracking Filter and Feedback Integration1）

Institute of Scientific and Technical Information of China (English)

YANGGuo-Sheng; WENCheng-Lin; TANMin

2004-01-01

A new multisensor distributed track fusion algorithm is put forward based on combiningthe feedback integration with the strong tracking Kalman filter. Firstly, an effective tracking gateis constructed by taking the intersection of the tracking gates formed before and after feedback.Secondly, on the basis of the constructed effective tracking gate, probabilistic data association andstrong tracking Kalman filter are combined to form the new multisensor distributed track fusionalgorithm. At last, simulation is performed on the original algorithm and the algorithm presented.

Facile synthesis of hollow Co3O4 microspheres and its use as a rapid responsive CL sensor of combustible gases.

Science.gov (United States)

Teng, Fei; Yao, Wenqing; Zheng, Youfei; Ma, Yutao; Xu, Tongguang; Gao, Guizhi; Liang, Shuhui; Teng, Yang; Zhu, Yongfa

2008-09-15

The hollow Co(3)O(4) microspheres (HCMs) were prepared by the carbonaceous templates, which did not need the surface pretreatment. The chemiluminescence (CL) and catalytic properties for CO oxidation over these hollow samples were evaluated. The samples were characterized by scanning electron microscopy (SEM), energy disperse spectra (EDS), transmission electron microscopy (TEM), selected area electron diffraction (ED), X-ray diffraction (XRD), temperature-programmed desorption (TPD) and N(2) adsorption. The influences of filter' band length, flow rate of gas, test temperature, and particle structure on CL intensities were mainly investigated. It was found that compared with the solid Co(3)O(4) particles (SCPs), HCMs had a stronger CL intensity, which was ascribed to its hollow structure; and that CL properties of the catalysts were well correlated with their reaction activities. Moreover, HCMs were used to fabricate a highly sensitive gas detector, which is a rapid and effective method for the selection of catalysts or the detection of environmental deleterious gases.

Oxyfuel combustion using a catalytic ceramic membrane reactor

Energy Technology Data Exchange (ETDEWEB)

Tan, Xiaoyao; Li, K. [Department of Chemical Engineering, Imperial College London, University of London, South Kensington, London SW7 2AZ (United Kingdom); Thursfield, A.; Metcalfe, I.S. [School of Chemical Engineering and Advanced Materials, Newcastle University, Newcastle upon Tyne, NE1 7RU (United Kingdom)

2008-02-29

Membrane catalytic combustion (MCC) is an environmentally friendly technique for heat and power generation from methane. This work demonstrates the performances of a MCC perovskite hollow fibre membrane reactor for the catalytic combustion of methane. The ionic-electronic La{sub 0.6}Sr{sub 0.4}Co{sub 0.2}Fe{sub 0.8}O{sub 3-{alpha}} (LSCF6428) mixed conductor, in the form of an oxygen-permeable hollow fibre membrane, has been prepared successfully by means of a phase-inversion spinning/sintering technique. For this process polyethersulfone (PESf) was used as a binder, N-methyl-2-pyrrollidone (NMP) as solvent and polyvinylpyrrolidone (PVP, K16-18) as an additive. With the prepared LSCF6428 hollow fibre membranes packed with catalyst, hollow fibre membrane reactors (HFMRs) have been assembled to perform the catalytic combustion of methane. A simple mathematical model that combines the local oxygen permeation rate with approximate catalytic reaction kinetics has been developed and can be used to predict the performance of the HFMRs for methane combustion. The effects of operating temperature and methane and air feed flow rates on the performance of the HFMR have been investigated both experimentally and theoretically. Both the methane conversion and oxygen permeation rate can be improved by means of coating platinum on the air side of the hollow fibre membranes. (author)

Concrete workability and fibre content

OpenAIRE

Vikan, Hedda

2007-01-01

Research report Parameters influencing the workability of fibre concrete and maximum fibre content are given in this state of the art report along with the range of fibre types available on today’s market. The study reveales that new placing techniques and production methods are crucial in order to increase fibre content and concrete strength. Achieving the same mechanical properties as traditionally reinforced concrete will probably also demand changes of the matrix. Finally, reco...

Insulation Characteristics of Sisal Fibre/Epoxy Composites

Directory of Open Access Journals (Sweden)

A. Shalwan

2017-01-01

Full Text Available Using natural fibres in civil engineering is the aim of many industrial and academics sectors to overcome the impact of synthetic fibres on environments. One of the potential applications of natural fibres composites is to be implemented in insulation components. Thermal behaviour of polymer composites based on natural fibres is recent ongoing research. In this article, thermal characteristics of sisal fibre reinforced epoxy composites are evaluated for treated and untreated fibres considering different volume fractions of 0–30%. The results revealed that the increase in the fibre volume fraction increased the insulation performance of the composites for both treated and untreated fibres. More than 200% insulation rate was achieved at the volume fraction of 20% of treated sisal fibres. Untreated fibres showed about 400% insulation rate; however, it is not recommended to use untreated fibres from mechanical point of view. The results indicated that there is potential of using the developed composites for insulation purposes.

Boundary integral method to calculate the sensitivity temperature error of microstructured fibre plasmonic sensors

International Nuclear Information System (INIS)

Esmaeilzadeh, Hamid; Arzi, Ezatollah; Légaré, François; Hassani, Alireza

2013-01-01

In this paper, using the boundary integral method (BIM), we simulate the effect of temperature fluctuation on the sensitivity of microstructured optical fibre (MOF) surface plasmon resonance (SPR) sensors. The final results indicate that, as the temperature increases, the refractometry sensitivity of our sensor decreases from 1300 nm/RIU at 0 °C to 1200 nm/RIU at 50 °C, leading to ∼7.7% sensitivity reduction and the sensitivity temperature error of 0.15% °C −1 for this case. These results can be used for biosensing temperature-error adjustment in MOF SPR sensors, since biomaterials detection usually happens in this temperature range. Moreover, the signal-to-noise ratio (SNR) of our sensor decreases from 0.265 at 0 °C to 0.154 at 100 °C with the average reduction rate of ∼0.42% °C −1 . The results suggest that at lower temperatures the sensor has a higher SNR. (paper)

The Electrospun Ceramic Hollow Nanofibers

Directory of Open Access Journals (Sweden)

Shahin Homaeigohar

2017-11-01

Full Text Available Hollow nanofibers are largely gaining interest from the scientific community for diverse applications in the fields of sensing, energy, health, and environment. The main reasons are: their extensive surface area that increases the possibilities of engineering, their larger accessible active area, their porosity, and their sensitivity. In particular, semiconductor ceramic hollow nanofibers show greater space charge modulation depth, higher electronic transport properties, and shorter ion or electron diffusion length (e.g., for an enhanced charging–discharging rate. In this review, we discuss and introduce the latest developments of ceramic hollow nanofiber materials in terms of synthesis approaches. Particularly, electrospinning derivatives will be highlighted. The electrospun ceramic hollow nanofibers will be reviewed with respect to their most widely studied components, i.e., metal oxides. These nanostructures have been mainly suggested for energy and environmental remediation. Despite the various advantages of such one dimensional (1D nanostructures, their fabrication strategies need to be improved to increase their practical use. The domain of nanofabrication is still advancing, and its predictable shortcomings and bottlenecks must be identified and addressed. Inconsistency of the hollow nanostructure with regard to their composition and dimensions could be one of such challenges. Moreover, their poor scalability hinders their wide applicability for commercialization and industrial use.

Luminescent Solar Concentrators with Fibre Geometry

NARCIS (Netherlands)

Edelenbosch, O.Y.; Fisher, M.; Patrignani, L.; Sark, W.G.J.H.M. van; Chatten, A.J.

2013-01-01

The potential of a fibre luminescent solar concentrator has been explored by means of both analytical and ray-tracing techniques. Coated fibres have been found to be more efficient than homogeneously doped fibres, at low absorption. For practical fibres concentration is predicted to be linear

Evolution of nickel sulfide hollow spheres through topotactic transformation

Science.gov (United States)

Wei, Chengzhen; Lu, Qingyi; Sun, Jing; Gao, Feng

2013-11-01

In this study, a topotactic transformation route was proposed to synthesize single-crystalline β-NiS hollow spheres with uniform phase and morphology evolving from polycrystalline α-NiS hollow spheres. Uniform polycrystalline α-NiS hollow spheres were firstly prepared with thiourea and glutathione as sulfur sources under hydrothermal conditions through the Kirkendall effect. By increasing the reaction temperature the polycrystalline α-NiS hollow spheres were transformed to uniform β-NiS hollow spheres. The β-NiS crystals obtained through the topotactic transformation route not only have unchanged morphology of hollow spheres but are also single-crystalline in nature. The as-prepared NiS hollow spheres display a good ability to remove the organic pollutant Congo red from water, which makes them have application potential in water treatment.In this study, a topotactic transformation route was proposed to synthesize single-crystalline β-NiS hollow spheres with uniform phase and morphology evolving from polycrystalline α-NiS hollow spheres. Uniform polycrystalline α-NiS hollow spheres were firstly prepared with thiourea and glutathione as sulfur sources under hydrothermal conditions through the Kirkendall effect. By increasing the reaction temperature the polycrystalline α-NiS hollow spheres were transformed to uniform β-NiS hollow spheres. The β-NiS crystals obtained through the topotactic transformation route not only have unchanged morphology of hollow spheres but are also single-crystalline in nature. The as-prepared NiS hollow spheres display a good ability to remove the organic pollutant Congo red from water, which makes them have application potential in water treatment. Electronic supplementary information (ESI) available: XRD patterns; SEM images and TEM images. See DOI: 10.1039/c3nr03371f

Air Separation Using Hollow Fiber Membranes

Science.gov (United States)

Huang, Stephen E.

2004-01-01

The NASA Glenn Research Center in partnership with the Ohio Aerospace Institute provides internship programs for high school and college students in the areas of science, engineering, professional administrative, and other technical areas. During the summer of 2004, I worked with Dr. Clarence T. Chang at NASA Glenn Research Center s combustion branch on air separation using hollow fiber membrane technology. . In light of the accident of Trans World Airline s flight 800, FAA has mandated that a suitable solution be created to prevent the ignition of fuel tanks in aircrafts. In order for any type of fuel to ignite, three important things are needed: fuel vapor, oxygen, and an energy source. Two different ways to make fuel tanks less likely to ignite are reformulating the fuel to obtain a lower vapor pressure for the fuel and or using an On Board Inert Gas Generating System (OBIGGS) to inert the Central Wing Tank. goal is to accomplish the mission, which means that the Air Separation Module (ASM) tends to be bulky and heavy. The primary goal for commercial aviation companies is to transport as much as they can with the least amount of cost and fuel per person, therefore the ASM must be compact and light as possible. The plan is to take bleed air from the aircraft s engines to pass air through a filter first to remove particulates and then pass the air through the ASM containing hollow fiber membranes. In the lab, there will be a heating element provided to simulate the temperature of the bleed air that will be entering the ASM and analysis of the separated air will be analyzed by a Gas Chromatograph/Mass Spectrometer (GC/MS). The GUMS will separate the different compounds in the exit streams of the ASM and provide information on the performance of hollow fiber membranes. Hopefully I can develop ways to improve efficiency of the ASM. different types of jet fuel were analyzed and data was well represented on SAE Paper 982485. Data consisted of the concentrations of over

Design of a Miniaturized X-Band Diplexer Based on Novel One-Third-Mode Substrate Integrated Resonator Filters

Science.gov (United States)

Zhang, Hao; Kang, Wei; Wu, Wen

2017-12-01

In this paper, a miniaturized diplexer designed with two novel one-third-mode substrate integrated resonator (OTMSIR) filters has been presented. The one-third triangular resonator cavity with two transmission zeros (TZs) and two transmission poles is investigated. TZs are implemented by taking cross couplings of lower order modes in this design. The diplexer is then obtained by integrating two different sizes of OTMSIR filters with a common T-junction structure. A X-band diplexer operating at 10 GHz and 11.5 GHz is designed on a substrate with a dielectric constant of 3.55 to verify the above design concept. This novel structure features more compact size, better transmission performance, higher out of band rejection and easier integration compared with other circuits. A good agreement is obtained between the simulations and the measured results.

Optical fibre sensing: a solution for industry

Science.gov (United States)

Sun, T.; Fabian, M.; Chen, Y.; Vidakovic, M.; Javdani, S.; Grattan, K. T. V.; Carlton, J.; Gerada, C.; Brun, L.

2017-04-01

Optical fibres have been explored widely for their sensing capability to meet increasing industrial needs, building on their success in telecommunications. This paper provides a review of research activities at City University of London in response to industrial challenges through the development of a range of fibre Bragg grating (FBG)-based sensors for transportation structural monitoring. For marine propellers, arrays of FBGs mapped onto the surface of propeller blades allow for capturing vibrational modes, with reference to simulation data. The research funded by EU Cleansky programme enables the development of self-sensing electric motor drives to support `More Electric Aircraft' concept. The partnership with Faiveley Brecknell Willis in the UK enables the integration of FBG sensors into the railway current-collecting pantographs for real-time condition monitoring when they are operating under 25kV conditions.

Proposing Wavelet-Based Low-Pass Filter and Input Filter to Improve Transient Response of Grid-Connected Photovoltaic Systems

Directory of Open Access Journals (Sweden)

Bijan Rahmani

2016-08-01

Full Text Available Available photovoltaic (PV systems show a prolonged transient response, when integrated into the power grid via active filters. On one hand, the conventional low-pass filter, employed within the integrated PV system, works with a large delay, particularly in the presence of system’s low-order harmonics. On the other hand, the switching of the DC (direct current–DC converters within PV units also prolongs the transient response of an integrated system, injecting harmonics and distortion through the PV-end current. This paper initially develops a wavelet-based low-pass filter to improve the transient response of the interconnected PV systems to grid lines. Further, a damped input filter is proposed within the PV system to address the raised converter’s switching issue. Finally, Matlab/Simulink simulations validate the effectiveness of the proposed wavelet-based low-pass filter and damped input filter within an integrated PV system.

Ceramic-supported thin PVA pervaporation membranes combining high flux and high selectivity : contradicting the flux-selectivity paradigm

NARCIS (Netherlands)

Peters, T.A.; Poeth, C.H.S.; Benes, N.E.; Buijs, H.C.W.M.; Vercauteren, F.F.; Keurentjes, J.T.F.

2006-01-01

Thin, high-flux and highly selective cross-linked poly(vinyl)alcohol waterselective layers have been prepared on top of hollow fibre ceramic supports. The supports consist of an alpha-Al2O3 hollow fibre substrate and an intermediate gamma-Al2O3 layer, which provides a sufficiently smooth surface for

Thermal expansion of fibre-reinforced composites

International Nuclear Information System (INIS)

Schneider, B.

1991-07-01

The integral thermal expansion and the coefficient of thermal expansion (CTE) of carbon and Kevlar fibre-reinforced composites were measured with high accuracy from 5 K to room temperature. For this, a laser dilatometer and a sophisticated measuring procedure were used. CTE dependence on the orientation angle ω of angle-ply laminates was determined for samples with 5 different fibre alignments (UD 0deg, +/-30deg, +/-45deg, +/-60deg and UD 90deg). A high variability of the CTE with the orientation angle was shown. At angles of approximately +/-30deg even negative CTEs were found. With suitable reinforcing fibres being selected, their absolute values rose up to 30-100% of the positive CTEs of metals. Hence, composites of this type would be suitable as compensating materials in metal constructions where little thermal expansion is desired. To check the lamination theory, theoretical computations of the CTE- ω -dependence were compared with the measured values. An excellent agreement was found. Using the lamination theory, predictions about the expansion behaviour of angle-ply laminates can be made now, if the thermal and mechanical properties of the unidirectional (UD) laminate are known. Furthermore, it is possible to carry out simulation computations aimed at investigating the influence of a single parameter of the UD-laminate (e.g. shear modulus) on the expansion of the angle-ply laminate. (orig.) [de

The calculation of average error probability in a digital fibre optical communication system

Science.gov (United States)

Rugemalira, R. A. M.

1980-03-01

This paper deals with the problem of determining the average error probability in a digital fibre optical communication system, in the presence of message dependent inhomogeneous non-stationary shot noise, additive Gaussian noise and intersymbol interference. A zero-forcing equalization receiver filter is considered. Three techniques for error rate evaluation are compared. The Chernoff bound and the Gram-Charlier series expansion methods are compared to the characteristic function technique. The latter predicts a higher receiver sensitivity

HIPPI and Fibre Channel

International Nuclear Information System (INIS)

Tolmie, D.E.

1992-01-01

The High-Performance Parallel Interface (HIPPI) and Fibre Channel are near-gigabit per second data communications interfaces being developed in ANSI standards Task Group X3T9.3. HIPPI is the current interface of choice in the high-end and supercomputer arena, and Fibre Channel is a follow-on effort. HIPPI came from a local area network background, and Fibre Channel came from a mainframe to peripheral interface background

Kenaf-and hemp-reinforced natural fibre composites

International Nuclear Information System (INIS)

Sharifah Hanisah Aziz

2003-01-01

The main aim of this research is to combine hemp and kenaf fibres with thermosetting resin matrices to produce sustainable composites and to investigate their mechanical properties. The matirces used in this work are based on either unsaturated polyester resins or cashew nut shell liquid (CNSL). The latter can be polymerised to form a phenolic-based natural resin. Four types of differently formulated polyester resins provided by Scott Bader Ltd, a UK-based resin company, were used to assess the effect of resin formulation on the properties of natural fibre composites. CSNL resins were used because CNSL is a sustainable resource and these resins are compatible with natural fibres. Kenaf, which is extensively grown in the Far East including Malaysia, has been identified as a bast (stem) fibre with significant market potential. Hemp is a United Kingdom-grown bast fibre with strong potential as a natural fibre reinforcement. In order to improve matrix to fibre adhesion, the fibres were treated with 6 % NaOH solution before being made into composites. The composites were fabricated using unidirectional and randomly oriented fibres to assess the effect of fibre alignment on the properties of the composites. The effect of moulding pressure on the fibre volume fraction and mechanical properties was also investigated. Kenaf and hemp fibre composites were successfully hot-pressed with polyester and CNSL resin matrices. Kenaf-CNSL (treated long fibre) composites possess the highest flexural modulus (MOE) at 16.7 GPa and flexural strength (MOR) at 165.4 MPa indicating good matrix to fibre adhesion. Generally, the treated fibre composites gave higher MOE and MOR values compared to the untreated composites. However, the work of fracture values were generally higher for the untreated fibre composites. among the four types of polyester used, the molecular structure of polyester B, modified to make it more polar in nature, resulted in the best performance with treated long kenaf

Hollow core plasma channel generation

International Nuclear Information System (INIS)

Quast, Heinrich Martin

2018-03-01

The use of a hollow plasma channel in plasma-based acceleration has beneficial properties for the acceleration of electron and positron bunches. In the scope of the FLASHForward facility at DESY, the generation of such a plasma structure is examined. Therefore, the generation of a ring-shaped laser intensity profile with different techniques is analyzed. From the obtained intensity profiles the electron density of a hollow plasma channel is simulated in the focal region. Different parameters are scanned to understand their influence on the electron density distribution - an important parameter being, for example, the radius of the central region of the channel. In addition to the simulations, experiments are presented, during which a laser pulse is transformed into a hollow beam with a spiral phase plate. Subsequently, it forms a plasma during the interaction with hydrogen, where the plasma is imaged with interferometry. For energies above 0.9 mJ a hollow plasma structure can be observed at the location of first plasma formation.

A top-down approach for fabricating three-dimensional closed hollow nanostructures with permeable thin metal walls

Directory of Open Access Journals (Sweden)

Carlos Angulo Barrios

2017-06-01

Full Text Available We report on a top-down method for the controlled fabrication of three-dimensional (3D, closed, thin-shelled, hollow nanostructures (nanocages on planar supports. The presented approach is based on conventional microelectronic fabrication processes and exploits the permeability of thin metal films to hollow-out polymer-filled metal nanocages through an oxygen-plasma process. The technique is used for fabricating arrays of cylindrical nanocages made of thin Al shells on silicon substrates. This hollow metal configuration features optical resonance as revealed by spectral reflectance measurements and numerical simulations. The fabricated nanocages were demonstrated as a refractometric sensor with a measured bulk sensitivity of 327 nm/refractive index unit (RIU. The pattern design flexibility and controllability offered by top-down nanofabrication techniques opens the door to the possibility of massive integration of these hollow 3D nano-objects on a chip for applications such as nanocontainers, nanoreactors, nanofluidics, nano-biosensors and photonic devices.

A top-down approach for fabricating three-dimensional closed hollow nanostructures with permeable thin metal walls.

Science.gov (United States)

Barrios, Carlos Angulo; Canalejas-Tejero, Víctor

2017-01-01

We report on a top-down method for the controlled fabrication of three-dimensional (3D), closed, thin-shelled, hollow nanostructures (nanocages) on planar supports. The presented approach is based on conventional microelectronic fabrication processes and exploits the permeability of thin metal films to hollow-out polymer-filled metal nanocages through an oxygen-plasma process. The technique is used for fabricating arrays of cylindrical nanocages made of thin Al shells on silicon substrates. This hollow metal configuration features optical resonance as revealed by spectral reflectance measurements and numerical simulations. The fabricated nanocages were demonstrated as a refractometric sensor with a measured bulk sensitivity of 327 nm/refractive index unit (RIU). The pattern design flexibility and controllability offered by top-down nanofabrication techniques opens the door to the possibility of massive integration of these hollow 3D nano-objects on a chip for applications such as nanocontainers, nanoreactors, nanofluidics, nano-biosensors and photonic devices.

Optical fibre laser velocimetry: a review

International Nuclear Information System (INIS)

Charrett, Thomas O H; James, Stephen W; Tatam, Ralph P

2012-01-01

The applications of optical fibre technology to laser velocimetry are diverse and often critical to their successful implementation, particularly in harsh environments. Applications range from the use of optical fibres for beam delivery and scattered light collection, aiding the miniaturization of instrument probes, to the use of imaging fibre bundles for imaging the flow field in planar velocimetry systems. Optical fibre techniques have also been used in signal processing, for example fibre frequency shifters, and optical fibre devices such as amplifiers and lasers have been exploited. This paper will review the use of optical fibres in point-wise laser velocimetry techniques such as laser Doppler velocimetry and laser transit anemometry, as well as in planar measurement techniques such as particle imaging velocimetry and planar Doppler velocimetry. (topical review)

A linear 180 nm SOI CMOS antenna switch module using integrated passive device filters for cellular applications

International Nuclear Information System (INIS)

Cui Jie; Chen Lei; Liu Yi; Zhao Peng; Niu Xu

2014-01-01

A broadband monolithic linear single pole, eight throw (SP8T) switch has been fabricated in 180 nm thin film silicon-on-insulator (SOI) CMOS technology with a quad-band GSM harmonic filter in integrated passive devices (IPD) technology, which is developed for cellular applications. The antenna switch module (ASM) features 1.2 dB insertion loss with filter on 2G bands and 0.4 dB insertion loss in 3G bands, less than −45 dB isolation and maximum −103 dB intermodulation distortion for mobile front ends by applying distributed architecture and adaptive supply voltage generator. (semiconductor integrated circuits)

Fatigue processes in thermoplastic fibres; Les mecanismes de fatigue dans les fibres thermoplastiques

Energy Technology Data Exchange (ETDEWEB)

Herrera Ramirez, J.M.

2004-09-15

The present study examines and compares the behaviour of the two types of PA66 fibres and two types of PET fibres under fatigue loading up to failure, and the correlation between the fibres (nano)structures and their structural heterogeneities, with fatigue lifetimes. Several techniques have been used to analyze the materials, such as scanning electron microscopy (SEM), microanalysis (EDS), differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXD) and micro-Raman spectroscopy. A meticulous analysis by scanning electron microscopy of the fracture morphology of fibres broken in tension and in fatigue, as well as a study of the fatigue life, were undertaken. The fatigue process occurs when the cyclic load amplitude is sufficiently large, however a condition for fatigue failure is that the minimum load each cycle must be lower than a threshold stress level. Failure under fatigue conditions leads to distinctive fracture morphologies which are very different from those seen after tensile or creep failure and this allows easy identification of the fatigue process. The fibres have been analyzed in the as received state and after fatigue failure in order to observe the microstructural changes resulting from the fatigue loading. The results will be compared with those obtained for fibres loaded under conditions where the fatigue process was hindered. The role of the microstructure of the fibres in determining fatigue will be discussed in this work and the possibility of improving their resistance to fatigue or eliminating the fatigue process will be discussed. (author)

Effects of time-temperature profiles on glow curves of germanium-doped optical fibre

Science.gov (United States)

Lam, S. E.; Alawiah, A.; Bradley, D. A.; Mohd Noor, N.

2017-08-01

The Germanium (Ge) doped silica optical fibres have demonstrated the great potential to be developed as a thermoluminescent (TL) dosimeter that can be used in various applications in radiotherapy, diagnostic radiology, UV dosimetry system and food irradiation industry. Different time-temperature profile (TTP) parameters of the TL reader have been employed by many researchers in various of TL studies. Nevertheless, none of those studies adequately addressed the effects of the reader's preheat temperature and heating rate on the kinetic parameters of the TL glow curve specifically, the Ge-doped silica optical fibres. This research addresses the issue of TTP parameters with special attention to the determination of the kinetic parameters of the glow curve. The glow curve responses were explored and the kinetic parameters were analyzed by the WinGCF software, to show the effect of the preheat temperature and heating rate of the reader on Ge-doped fibre irradiated with 18 Gy of 6 MV photons radiation. The effect of TTP parameters was discussed and compared against the commercial fibre and tailored made fibre of 6 mol% Ge-doped of flat and cylindrical shape. The deconvolution of glow peaks and the kinetic parameters were obtained by the WinGCF software. This enables to fit accurately (1.5%fibre (50 °C) and cylindrical fibre (80 °C and 160 °C). It is found that the glow peaks of cylindrical fibre exhibit the highest peak integral as compared to flat and commercial fibres. This study revealed the possible relationship between the reader's TTP parameters and the kinetic parameters of TL glow curves for the commercial and tailored made Ge-doped silica optical fibres.

Study of injection moulded long glass fibre-reinforced polypropylene and the effect on the fibre length and orientation distribution

Science.gov (United States)

Parveeen, B.; Caton-Rose, P.; Costa, F.; Jin, X.; Hine, P.

2014-05-01

Long glass fibre (LGF) composites are extensively used in manufacturing to produce components with enhanced mechanical properties. Long fibres with length 12 to 25mm are added to a thermoplastic matrix. However severe fibre breakage can occur in the injection moulding process resulting in shorter fibre length distribution (FLD). The majority of this breakage occurs due to the melt experiencing extreme shear stress during the preparation and injection stage. Care should be taken to ensure that the longer fibres make it through the injection moulding process without their length being significantly degraded. This study is based on commercial 12 mm long glass-fibre reinforced polypropylene (PP) and short glass fibre Nylon. Due to the semi-flexiable behaviour of long glass fibres, the fibre orientation distribution (FOD) will differ from the orientation distribution of short glass fibre in an injection molded part. In order to investigate the effect the change in fibre length has on the fibre orientation distribution or vice versa, FOD data was measured using the 2D section image analyser. The overall purpose of the research is to show how the orientation distribution chnages in an injection moulded centre gated disc and end gated plaque geometry and to compare this data against fibre orientation predictions obtained from Autodesk Moldflow Simulation Insight.

Plasma treatment of carbon fibres and glass-fibre-reinforced polyesters at atmospheric pressure for adhesion improvement

DEFF Research Database (Denmark)

Kusano, Yukihiro; Løgstrup Andersen, Tom; Toftegaard, Helmuth Langmaack

2014-01-01

Atmospheric pressure plasma treatment is useful for adhesion improvement, because cleaning, roughening and addition of polar functional groups can be expected at the surfaces. Its possible applications in the wind energy industry include plasma treatment of fibres and fibre-reinforced polymer...... composites before assembling them to build wind turbine blades. In the present work, unsized carbon fibres are continuously treated using a dielectric barrier discharge plasma in helium at atmospheric pressure, and carbon fibre reinforced epoxy composite plates are manufactured for the mechanical test....... The plasma treatment improved fracture toughness, indicating that adhesion between the fibres and the epoxy was enhanced by the treatment. In addition, glass-fibre-reinforced polyester plates are treated using a gliding arc and an ultrasound enhanced dielectric barrier discharge, improving the wettability...

Random distributed feedback fibre lasers

Energy Technology Data Exchange (ETDEWEB)

Turitsyn, Sergei K., E-mail: s.k.turitsyn@aston.ac.uk [Aston Institute of Photonic Technologies, Aston University, Birmingham B4 7ET (United Kingdom); Novosibirsk State University, 2 Pirogova str., 630090, Novosibirsk (Russian Federation); Babin, Sergey A. [Novosibirsk State University, 2 Pirogova str., 630090, Novosibirsk (Russian Federation); Institute of Automation and Electrometry SB RAS, 1 Ac. Koptug. ave., 630090, Novosibirsk (Russian Federation); Churkin, Dmitry V. [Aston Institute of Photonic Technologies, Aston University, Birmingham B4 7ET (United Kingdom); Novosibirsk State University, 2 Pirogova str., 630090, Novosibirsk (Russian Federation); Institute of Automation and Electrometry SB RAS, 1 Ac. Koptug. ave., 630090, Novosibirsk (Russian Federation); Vatnik, Ilya D.; Nikulin, Maxim [Institute of Automation and Electrometry SB RAS, 1 Ac. Koptug. ave., 630090, Novosibirsk (Russian Federation); Podivilov, Evgenii V. [Novosibirsk State University, 2 Pirogova str., 630090, Novosibirsk (Russian Federation); Institute of Automation and Electrometry SB RAS, 1 Ac. Koptug. ave., 630090, Novosibirsk (Russian Federation)

2014-09-10

The concept of random lasers exploiting multiple scattering of photons in an amplifying disordered medium in order to generate coherent light without a traditional laser resonator has attracted a great deal of attention in recent years. This research area lies at the interface of the fundamental theory of disordered systems and laser science. The idea was originally proposed in the context of astrophysics in the 1960s by V.S. Letokhov, who studied scattering with “negative absorption” of the interstellar molecular clouds. Research on random lasers has since developed into a mature experimental and theoretical field. A simple design of such lasers would be promising for potential applications. However, in traditional random lasers the properties of the output radiation are typically characterized by complex features in the spatial, spectral and time domains, making them less attractive than standard laser systems in terms of practical applications. Recently, an interesting and novel type of one-dimensional random laser that operates in a conventional telecommunication fibre without any pre-designed resonator mirrors–random distributed feedback fibre laser–was demonstrated. The positive feedback required for laser generation in random fibre lasers is provided by the Rayleigh scattering from the inhomogeneities of the refractive index that are naturally present in silica glass. In the proposed laser concept, the randomly backscattered light is amplified through the Raman effect, providing distributed gain over distances up to 100 km. Although an effective reflection due to the Rayleigh scattering is extremely small (∼0.1%), the lasing threshold may be exceeded when a sufficiently large distributed Raman gain is provided. Such a random distributed feedback fibre laser has a number of interesting and attractive features. The fibre waveguide geometry provides transverse confinement, and effectively one-dimensional random distributed feedback leads to the

Random distributed feedback fibre lasers

International Nuclear Information System (INIS)

Turitsyn, Sergei K.; Babin, Sergey A.; Churkin, Dmitry V.; Vatnik, Ilya D.; Nikulin, Maxim; Podivilov, Evgenii V.

2014-01-01

The concept of random lasers exploiting multiple scattering of photons in an amplifying disordered medium in order to generate coherent light without a traditional laser resonator has attracted a great deal of attention in recent years. This research area lies at the interface of the fundamental theory of disordered systems and laser science. The idea was originally proposed in the context of astrophysics in the 1960s by V.S. Letokhov, who studied scattering with “negative absorption” of the interstellar molecular clouds. Research on random lasers has since developed into a mature experimental and theoretical field. A simple design of such lasers would be promising for potential applications. However, in traditional random lasers the properties of the output radiation are typically characterized by complex features in the spatial, spectral and time domains, making them less attractive than standard laser systems in terms of practical applications. Recently, an interesting and novel type of one-dimensional random laser that operates in a conventional telecommunication fibre without any pre-designed resonator mirrors–random distributed feedback fibre laser–was demonstrated. The positive feedback required for laser generation in random fibre lasers is provided by the Rayleigh scattering from the inhomogeneities of the refractive index that are naturally present in silica glass. In the proposed laser concept, the randomly backscattered light is amplified through the Raman effect, providing distributed gain over distances up to 100 km. Although an effective reflection due to the Rayleigh scattering is extremely small (∼0.1%), the lasing threshold may be exceeded when a sufficiently large distributed Raman gain is provided. Such a random distributed feedback fibre laser has a number of interesting and attractive features. The fibre waveguide geometry provides transverse confinement, and effectively one-dimensional random distributed feedback leads to the

Comparison of robust H∞ filter and Kalman filter for initial alignment of inertial navigation system

Institute of Scientific and Technical Information of China (English)

HAO Yan-ling; CHEN Ming-hui; LI Liang-jun; XU Bo

2008-01-01

There are many filtering methods that can be used for the initial alignment of an integrated inertial navigation system.This paper discussed the use of GPS,but focused on two kinds of filters for the initial alignment of an integrated strapdown inertial navigation system (SINS).One method is based on the Kalman filter (KF),and the other is based on the robust filter.Simulation results showed that the filter provides a quick transient response and a little more accurate estimate than KF,given substantial process noise or unknown noise statistics.So the robust filter is an effective and useful method for initial alignment of SINS.This research should make the use of SINS more popular,and is also a step for further research.

The Chemical Composition of Grape Fibre

OpenAIRE

Jolana Karovičová; Zlatica Kohajdová; Lucia Minarovičová; Veronika Kuchtová

2015-01-01

Dietary fibres from cereals are much more used than dietary fibres from fruits; however, dietary fibres from fruits have better quality. In recent years, for economic and environmental reasons, there has been a growing pressure to recover and exploit food wastes. Grape fibre is used to fortify baked goods, because the fibre can lower blood sugar, cut cholesterol and may even prevent colon cancer. Grape pomace is a functional ingredient in bakery goods to increase total phenolic content and di...

A spectrometer filter for semiconductor and scintillation detectors

International Nuclear Information System (INIS)

Andronov, O.I.; Brovchenko, V.G.; Evdokimov, S.T.

1995-01-01

The paper describes an integrating low-pass filter which takes signals from a delay line. The filter changes triangular pulses into rectangular ones. The energy resolution of a semiconductor detector whose signal is processed by the filter is 15-20% better than using a common RC-filter. The integrator stores a charge due to the scintillation pulse during the integration time without loss. The energy and time resolution of the device with the spectrometer filter is better than with an RC-filter. The energy resolution of a bismuth-germanate detector in recording radiation from 137 Cs is 9.75%

Fibre optic microarrays.

Science.gov (United States)

Walt, David R

2010-01-01

This tutorial review describes how fibre optic microarrays can be used to create a variety of sensing and measurement systems. This review covers the basics of optical fibres and arrays, the different microarray architectures, and describes a multitude of applications. Such arrays enable multiplexed sensing for a variety of analytes including nucleic acids, vapours, and biomolecules. Polymer-coated fibre arrays can be used for measuring microscopic chemical phenomena, such as corrosion and localized release of biochemicals from cells. In addition, these microarrays can serve as a substrate for fundamental studies of single molecules and single cells. The review covers topics of interest to chemists, biologists, materials scientists, and engineers.

SEPHYDRO: An Integrated Multi-Filter Web-Based Tool for Baseflow Separation

Science.gov (United States)

Serban, D.; MacQuarrie, K. T. B.; Popa, A.

2017-12-01

Knowledge of baseflow contributions to streamflow is important for understanding watershed scale hydrology, including groundwater-surface water interactions, impact of geology and landforms on baseflow, estimation of groundwater recharge rates, etc. Baseflow (or hydrograph) separation methods can be used as supporting tools in many areas of environmental research, such as the assessment of the impact of agricultural practices, urbanization and climate change on surface water and groundwater. Over the past few decades various digital filtering and graphically-based methods have been developed in an attempt to improve the assessment of the dynamics of the various sources of streamflow (e.g. groundwater, surface runoff, subsurface flow); however, these methods are not available under an integrated platform and, individually, often require significant effort for implementation. Here we introduce SEPHYDRO, an open access, customizable web-based tool, which integrates 11 algorithms allowing for separation of streamflow hydrographs. The streamlined interface incorporates a reference guide as well as additional information that allows users to import their own data, customize the algorithms, and compare, visualise and export results. The tool includes one-, two- and three-parameter digital filters as well as graphical separation methods and has been successfully applied in Atlantic Canada, in studies dealing with nutrient loading to fresh water and coastal water ecosystems. Future developments include integration of additional separation algorithms as well as incorporation of geochemical separation methods. SEPHYDRO has been developed through a collaborative research effort between the Canadian Rivers Institute, University of New Brunswick (Fredericton, New Brunswick, Canada), Agriculture and Agri-Food Canada and Environment and Climate Change Canada and is currently available at http://canadianriversinstitute.com/tool/

Individual fibre segmentation from 3D X-ray computed tomography for characterising the fibre orientation in unidirectional composite materials

DEFF Research Database (Denmark)

Emerson, Monica Jane; Jespersen, Kristine Munk; Dahl, Anders Bjorholm

2017-01-01

The aim of this paper is to characterise the fibre orientation in unidirectional fibre reinforced polymers, namely glass and carbon fibre composites. The compression strength of the composite is related to the orientation of the fibres. Thus the orientation is essential when designing materials...... of composites with high fibre volume fraction. From the individual fibre orientations, it is possible to obtain results which are independent of the scanning quality. The compression strength for both composites is estimated from the average fibre orientations and is found to be of the same order of magnitude...

Hollow rods for the oil producing industry

Energy Technology Data Exchange (ETDEWEB)

Khalimova, L M; Elyasheva, M A

1970-01-01

Hollow sucker rods have several advantages over conventional ones. The hollow rods actuate the well pump and at the same time conduct produced fluids to surface. When paraffin deposition occurs, it can be minimized by injecting steam, hot oil or hot water into the hollow rod. Other chemicals, such as demulsifiers, scale inhibitors, corrosion inhibitors, etc., can also be placed in the well through the hollow rods. This reduces cost of preventive treatments, reduces number of workovers, increases oil production, and reduces cost of oil. Because the internal area of the rod is small, the passing liquids have a high velocity and thereby carry sand and dirt out of the well. This reduces pump wear between the piston and the plunger. Specifications of hollow rods, their operating characteristics, and results obtained with such rods under various circumstances are described.

Glass ceramic fibres

International Nuclear Information System (INIS)

Blaschek, O.; Paulitsch, P.

1983-01-01

As the correlation between mineralogical phase and chemical composition influences the type of application at different high temperatures, we studied the mineralogical phases of nine crystal glass fibres of the temperature ranges 1 150 degrees Celsius (Type 1), 1 400 degrees Celsius (Type 2) and 1 500 degrees Celsius (Type 3) at various high temperatures. The methods used in the study were microscopy, X-ray diffraction, transmission electron microscopy and differential thermal analysis. The investigations showed that mullite forms in glassy fibres of the system Al 2 O 3 . SiO 2 from 850 degrees Celsius to 990 degrees Celsius as 2/1 mullite; 3/2 mullite appeared above 990 degrees Celsius besides the crystallization of cristobalite. Fibres with 95 per cent Al 2 O 3 include the phases delta-Al 2 O 3 and alpha- Al 2 O 3 and mullite. Delta- Al 2 O 3 is stable up to 1 100 degrees Celsius. Alpha-Al 2 O 3 and mullite are only stable phases at 1 400 degrees Celsius. These different crystal phases influence the quality of the technical fibre according to the stability field of glass and crystals. This study has determined that it is possible to identify different fibres from different productions by their mineralogical compositions and to relate them to the high temperature application

Method for covering a spme fibre with carbon nanotubes and resulting spme fibre

OpenAIRE

Bertrán, Enric; Jover Comas, Eric; García Céspedes, Jordi; Bayona Termens, Josep María

2010-01-01

[EN] The invention relates to a method for covering solid phase microextraction (SPME) fibres with carbon nanotubes (CNT), comprising the following operations: (i) depositing a layer of a metal material on the SPME fibre; (ii) applying a heat treatment in order to form catalytic metal nanoparticles in a reducing atmosphere; and (iii) applying carbon using chemical deposition techniques, thereby forming CNT on top ofthe metal nanoparticles. The invention also relates to a fibre obtain...

FIBER OPTICS: Fibre optics: Forty years later

Science.gov (United States)

Dianov, Evgenii M.

2010-01-01

This paper presents a brief overview of the state of the art in fibre optics and its main applications: optical fibre communications, fibre lasers and fibre sensors for various physical property measurements. The future of fibre optics and the status of this important area of the modern technology in Russia are discussed.

Influence of the Testing Gage Length on the Strength, Young's Modulus and Weibull Modulus of Carbon Fibres and Glass Fibres

Directory of Open Access Journals (Sweden)

Luiz Claudio Pardini

2002-10-01

Full Text Available Carbon fibres and glass fibres are reinforcements for advanced composites and the fiber strength is the most influential factor on the strength of the composites. They are essentially brittle and fail with very little reduction in cross section. Composites made with these fibres are characterized by a high strength/density ratio and their properties are intrisically related to their microstructure, i.e., amount and orientation of the fibres, surface treatment, among other factors. Processing parameters have an important role in the fibre mechanical behaviour (strength and modulus. Cracks, voids and impurities in the case of glass fibres and fibrillar misalignments in the case of carbon fibres are created during processing. Such inhomogeneities give rise to an appreciable scatter in properties. The most used statistical tool that deals with this characteristic variability in properties is the Weibull distribution. The present work investigates the influence of the testing gage length on the strength, Young's modulus and Weibull modulus of carbon fibres and glass fibres. The Young's modulus is calculated by two methods: (i ASTM D 3379M, and (ii interaction between testing equipment/specimen The first method resulted in a Young modulus of 183 GPa for carbon fibre, and 76 GPa for glass fibre. The second method gave a Young modulus of 250 GPa for carbon fibre and 50 GPa for glass fibre. These differences revelead differences on how the interaction specimen/testing machine can interfere in the Young modulus calculations. Weibull modulus can be a tool to evaluate the fibre's homogeneity in terms of properties and it is a good quality control parameter during processing. In the range of specimen gage length tested the Weibull modulus for carbon fibre is ~ 3.30 and for glass fibres is ~ 5.65, which indicates that for the batch of fibres tested, the glass fibre is more uniform in properties.

Effects of Polarization–Maintaining Fibre Degrading on Precision of Fibre Optic Gyroscopes in Radiation Environment

International Nuclear Information System (INIS)

Wen, Xiao; De-Wen, Liu; Yang, Liu; Xiao-Su, Yi; Lin, Cong

2008-01-01

In the space environment, the precision of fibre optic gyroscopes (FOGs) degrades because of space radiation. Photonic components of FOGs are affected by radiation, especially the polarization-maintaining (PM) fibre coil. In relation to the space radiation environment characteristic, we have carried out a series of radiation experiments on a PM fibre coil with 60 Co radiation source at different dose rates. Based on the experimental results, the formula between the PM-fibre loss and radiation dose rate is built, and the relation between the precision of FOG and radiation dose is obtained accordingly. The results strongly show that the precision of our FOG degrades owing to the attenuation of the polarization-maintaining fibre, which provides theoretical foundation for the radiation-resistant design of the FOG

Development of nuclear safety class filter elements with long life and high quality

International Nuclear Information System (INIS)

Zhang Jinghua

2009-04-01

This paper describes the development on nuclear safety class filter elements with long life and high quality used for collecting radioactive contaminants, fragments of resin and impurities in primary systems of NPPs. The filter elements made of glass fibre elements are used for PWR, and of paper elements are used for PHWR. During the research, a series of tests for optimization were performed for selection of filter material and the improvement of binder. The flow rate and comprehensive performance have been measured in simulated conditions. The result shows that the application requirements for operational NPPs can be met, and the reliability and safety of the frame are also be verified. The comprehensive performance of the filter elements is equivalent to that of oversea similar products. The products have been used in NPPs in operation. (authors)

Performance comparison of various time variant filters

Energy Technology Data Exchange (ETDEWEB)

Kuwata, M [JEOL Engineering Co. Ltd., Akishima, Tokyo (Japan); Husimi, K

1996-07-01

This paper describes the advantage of the trapezoidal filter used in semiconductor detector system comparing with the other time variant filters. The trapezoidal filter is the compose of a rectangular pre-filter and a gated integrator. We indicate that the best performance is obtained by the differential-integral summing type rectangular pre-filter. This filter is not only superior in performance, but also has the useful feature that the rising edge of the output waveform is linear. We introduce an example of this feature used in a high-energy experiment. (author)

Dispersion properties of photonic crystal fibres

DEFF Research Database (Denmark)

Bjarklev, Anders Overgaard; Broeng, Jes; Dridi, Kim

1998-01-01

Approximate dispersion and bending properties of all-silica two-dimensional photonic crystal fibres are characterised by the combination of an effective-index model and classical analysis tools for optical fibres. We believe for the first time to have predicted the dispersion properties of photonic...... crystal fibres. The results strongly indicate that these fibres have potential applications as dispersion managing components...

Transmission properties of hollow-core photonic bandgap fibers

DEFF Research Database (Denmark)

Falk, Charlotte Ijeoma; Hald, Jan; Petersen, Jan C.

2010-01-01

Variations in optical transmission of four types of hollow-core photonic bandgap fibers are measured as a function of laser frequency. These variations influence the potential accuracy of gas sensors based on molecular spectroscopy in hollow-core fibers.......Variations in optical transmission of four types of hollow-core photonic bandgap fibers are measured as a function of laser frequency. These variations influence the potential accuracy of gas sensors based on molecular spectroscopy in hollow-core fibers....

A novel synthesis of micrometer silica hollow sphere

International Nuclear Information System (INIS)

Pan Wen; Ye Junwei; Ning Guiling; Lin Yuan; Wang Jing

2009-01-01

Silica microcapsules (hollow spheres) were synthesized successfully by a novel CTAB-stabilized water/oil emulsion system mediated hydrothermal method. The addition of urea to a solution of aqueous phase was an essential step of the simple synthetic procedure of silica hollow spheres, which leads to the formation of silica hollow spheres with smooth shell during hydrothermal process. The intact hollow spheres were obtained by washing the as-synthesized solid products with distilled water to remove the organic components. A large amount of silanol groups were retained in the hollow spheres by this facile route without calcination. The morphologies and optical properties of the product were characterized by transmission electron microscopy, scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy. Furthermore, on the basis of a series of SEM observations, phenomenological elucidation of a mechanism for the growth of the silica hollow spheres has been presented

Surface treated polypropylene (PP) fibres for reinforced concrete

Energy Technology Data Exchange (ETDEWEB)

López-Buendía, Angel M., E-mail: buendia@uv.es [AIDICO Technological Institute of Construction, Benjamin Franklin 17, 46380 Paterna, Valencia (Spain); Romero-Sánchez, María Dolores [AIDICO Technological Institute of Construction, Marble Technical Unit, Camí de Castella 4, 03660 Novelda. Alicante (Spain); Climent, Verónica [Lafarge Cementos, Polígono Sepes, Isaac Newton s/n, 46500 Sagunto, Valencia (Spain); Guillem, Celia [AIDICO Technological Institute of Construction, Marble Technical Unit, Camí de Castella 4, 03660 Novelda. Alicante (Spain)

2013-12-15

Surface treatments on a polypropylene (PP) fibre have contributed to the improvement of fibre/concrete adhesion in fibre-reinforced concrete. The treatments to the PP fibre were characterized by contact angle measurements, ATR-IR and XPS to analyse chemical alterations. The surface topography and fibre/concrete interaction were analysed by several microscopic techniques, namely optical petrographic, and scanning electron microscopy. Treatment modified the surface chemistry and topography of the fibre by introducing sodium moieties and created additional fibre surface roughness. Modifications in the fibre surface led to an increase in the adhesion properties between the treated fibres and concrete and an improvement in the mechanical properties of the fibre-reinforced concrete composite as compared to the concrete containing untreated PP fibres. Compatibility with the concrete and increased roughness and mineral surface was also improved by nucleated portlandite and ettringite mineral association anchored on the alkaline PP fibre surface, which is induced during treatment.

Fibre Bragg grating encapted with no-core fibre sensors for SRI and temperature monitoring

Directory of Open Access Journals (Sweden)

S. Daud

2018-06-01

Full Text Available In this work, a Fibre Bragg grating (FBG encapted with no-core fibre (NCF as surrounding refractive index (SRI and temperature sensors are practically demonstrated. A FBG with 1550 nm wavelength was attached with 5 cm length of no-core fibre (NCF is used as SRI and temperature sensing probe. The change of temperature and SRI induced the wavelength shift in FBG. The wavelength shift in FBG reacts directly proportional to the temperature with a sensitivity of while the sensitivity of NCF was measured as 13.13 pm °C−1. Keywords: FBG, No-core fibre (NCF, Temperature, Sensor

Investigation of different types of filters for atmospheric trace elements analysis by three analytical techniques

International Nuclear Information System (INIS)

Ali, A.E.; Bacso, J.

1996-01-01

Different atmospheric aerosol samples were collected on three types of filters. Disks of both loaded and clean areas of each kind of filter were investigated by XRF, PIXE and Scanning Electron Microscope (SEM) methods. The blank concentration values of the elements Al, Si, P, S, Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Br and Pb in the three types of filters are discussed. It is found that for trace elemental analysis, the Nuclepore membrane filters are the most suitable for sampling. These have much lower blank element concentration values than the glass fibres and ash free filters. It was found also that the PIXE method is a more reliable analytical technique for atmospheric aerosol particles than the other methods. (author). 20 refs., 3 figs., 3 tabs

Practical Hydrogen Loading of Air Silica Fibres

DEFF Research Database (Denmark)

Sørensen, Henrik Rokkjær; Jensen, Jesper Bevensee; Jensen, Jesper Bo Damm

2005-01-01

A method for hydrogen-loading air-silica optical fibres has been developed allowing out-diffusion times comparable to standard step-index fibres. Examples of the first grating written in Ge-doped air-silica fibres using a 266nm UV-laser are shown.......A method for hydrogen-loading air-silica optical fibres has been developed allowing out-diffusion times comparable to standard step-index fibres. Examples of the first grating written in Ge-doped air-silica fibres using a 266nm UV-laser are shown....

Mixed resin and carbon fibres surface treatment for preparation of carbon fibres composites with good interfacial bonding strength

International Nuclear Information System (INIS)

He, Hongwei; Wang, Jianlong; Li, Kaixi; Wang, Jian; Gu, Jianyu

2010-01-01

The objective of this work is to improve the interlaminar shear strength of composites by mixing epoxy resin and modifying carbon fibres. The effect of mixed resin matrix's structure on carbon fibres composites was studied. Anodic oxidation treatment was used to modify the surface of carbon fibres. The tensile strength of multifilament and interlaminar shear strength of composites were investigated respectively. The morphologies of untreated and treated carbon fibres were characterized by scanning electron microscope and X-ray photoelectron spectroscopy. Surface analysis indicates that the amount of carbon fibres chemisorbed oxygen-containing groups, active carbon atom, the surface roughness, and wetting ability increases after treatment. The tensile strength of carbon fibres decreased little after treatment by anodic oxidation. The results show that the treated carbon fibres composites could possess excellent interfacial properties with mixed resins, and interlaminar shear strength of the composites is up to 85.41 MPa. The mechanism of mixed resins and treated carbon fibres to improve the interfacial property of composites is obtained.

Fibre-Matrix Interaction in Soft Tissue

International Nuclear Information System (INIS)

Guo, Zaoyang

2010-01-01

Although the mechanical behaviour of soft tissue has been extensively studied, the interaction between the collagen fibres and the ground matrix has not been well understood and is therefore ignored by most constitutive models of soft tissue. In this paper, the human annulus fibrosus is used as an example and the potential fibre-matrix interaction is identified by careful investigation of the experimental results of biaxial and uniaxial testing of the human annulus fibrosus. First, the uniaxial testing result of the HAF along the axial direction is analysed and it is shown that the mechanical behaviour of the ground matrix can be well simulated by the incompressible neo-Hookean model when the collagen fibres are all under contraction. If the collagen fibres are stretched, the response of the ground matrix can still be described by the incompressible neo-Hookean model, but the effective stiffness of the matrix depends on the fibre stretch ratio. This stiffness can be more than 10 times larger than the one obtained with collagen fibres under contraction. This phenomenon can only be explained by the fibre-matrix interaction. Furthermore, we find that the physical interpretation of this interaction includes the inhomogeneity of the soft tissue and the fibre orientation dispersion. The dependence of the tangent stiffness of the matrix on the first invariant of the deformation tensor can also be explained by the fibre orientation dispersion. The significant effect of the fibre-matrix interaction strain energy on mechanical behaviour of the soft tissue is also illustrated by comparing some simulation results.

Sandwich-structured hollow fiber membranes for osmotic power generation

KAUST Repository

Fu, Feng Jiang; Zhang, Sui; Chung, Neal Tai-Shung

2015-01-01

In this work, a novel sandwich-structured hollow fiber membrane has been developed via a specially designed spinneret and optimized spinning conditions. With this specially designed spinneret, the outer layer, which is the most crucial part of the sandwich-structured membrane, is maintained the same as the traditional dual-layer membrane. The inner substrate layer is separated into two layers: (1) an ultra-thin middle layer comprising a high molecular weight polyvinylpyrrolidone (PVP) additive to enhance integration with the outer polybenzimidazole (PBI) selective layer, and (2) an inner-layer to provide strong mechanical strength for the membrane. Experimental results show that a high water permeability and good mechanical strength could be achieved without the expensive post treatment process to remove PVP which was necessary for the dual-layer pressure retarded osmosis (PRO) membranes. By optimizing the composition, the membrane shows a maximum power density of 6.23W/m2 at a hydraulic pressure of 22.0bar when 1M NaCl and 10mM NaCl are used as the draw and feed solutions, respectively. To our best knowledge, this is the best phase inversion hollow fiber membrane with an outer selective PBI layer for osmotic power generation. In addition, this is the first work that shows how to fabricate sandwich-structured hollow fiber membranes for various applications. © 2015 Elsevier B.V.

Sandwich-structured hollow fiber membranes for osmotic power generation

KAUST Repository

Fu, Feng Jiang

2015-11-01

In this work, a novel sandwich-structured hollow fiber membrane has been developed via a specially designed spinneret and optimized spinning conditions. With this specially designed spinneret, the outer layer, which is the most crucial part of the sandwich-structured membrane, is maintained the same as the traditional dual-layer membrane. The inner substrate layer is separated into two layers: (1) an ultra-thin middle layer comprising a high molecular weight polyvinylpyrrolidone (PVP) additive to enhance integration with the outer polybenzimidazole (PBI) selective layer, and (2) an inner-layer to provide strong mechanical strength for the membrane. Experimental results show that a high water permeability and good mechanical strength could be achieved without the expensive post treatment process to remove PVP which was necessary for the dual-layer pressure retarded osmosis (PRO) membranes. By optimizing the composition, the membrane shows a maximum power density of 6.23W/m2 at a hydraulic pressure of 22.0bar when 1M NaCl and 10mM NaCl are used as the draw and feed solutions, respectively. To our best knowledge, this is the best phase inversion hollow fiber membrane with an outer selective PBI layer for osmotic power generation. In addition, this is the first work that shows how to fabricate sandwich-structured hollow fiber membranes for various applications. © 2015 Elsevier B.V.

[Synthesis of hollow titania microspheres by using microfluidic droplet-template].

Science.gov (United States)

Ma, Jingyun; Jiang, Lei; Qin, Jianhu

2011-09-01

Droplet-based microfluidics is of great interest due to its particular characteristics compared with the conventional methods, such as reduced reagent consumption, rapid mixing, high-throughput, shape controlled, etc. A novel method using microfluidic droplet as soft template for the synthesis of hollow titania microspheres was developed. A typical polydimethylsiloxane (PDMS) microfluidic device containing "flow-focusing" geometry was used to generate water/oil (W/O) droplet. The mechanism for the hollow structure formation was based on the interfacial hydrolysis reaction between the continuous phase containing titanium butoxide precursor and the dispersed containing water. The continuous phase mixed with butanol was added in the downstream of the channel after the hydrolysis reaction. This step was used for drawing the water out of the microgels for further hydrolysis. The microgels obtained through a glass pipe integrated were washed, dried under vacuum and calcined after aging for a certain time. The fluorescence and scanning electron microscope (SEM) image of the microspheres indicated the hollow structure and the thickness of the shell. In addition, these microspheres with thin shell (about 2 microm) were apt to rupture and collapse. Droplet-based microfluidic offered a gentle and size-controllable manner to moderate this problem. Moreover, it has potential applications in photocatalysis combined with some modification realized on the chip simultaneously.

Fibre Optic Gyroscope Developments Using Integrated Optic Components

Science.gov (United States)

Minford, W. J.; DePaula, R. M.

1988-09-01

The sensing of rotation using counterpropagating optical beams in a fiber loop (the SAGNAC effect) has gone through extensive developments and demonstrations since first proved feasible by Vali and Shorthilll in 1976. The interferometric fiber gyroscope minimum configuration2 which uses a common input-output port and single-mode filter was developed to provide the extreme high stability necessary to reach the sensitivities at low rotation rates attainable with current state-of-the-art detectors. The simplicity and performance of this configuration has led to its acceptance and wide-spread use. In order to increase the mechanical stability of this system, all single-mode fiber components are employed and a further advancement to integrated optics has enabled most of the optical functions to be placed on a single mass-producible substrate. Recent improvements in the components (eg polarization maintaining fiber and low coherence sources) have further enhanced the performance of the minimum configuration gyro. This presentation focused on the impact of LiNbO3 integrated optic components on gyroscope developments. The use of Ti-indiffused LiNbO3 waveguide optical circuits in interferometric fiber optic gyroscopes has taken two directions: to utilize only the phase modulator, or to combine many of the minimum configuration optical functions on the electro-optic substrate. The high-bandwidth phase modulator is the driving force for using LiNbO3 waveguide devices. This device allows both biasing the gyro for maximum sensitivity and closing the loop via frequency shifting, for example, thus increasing the dynamic range of the gyro and the linearity of the scale factor. Efforts to implement most of the minimum configuration optical functions onto a single LiNbO3 substrate have been led by Thomson CSF.3 They have demonstrated an interferometric gyroscope with excellent performance using a LiNbO3 optical circuit containing a Y-splitter, phase modulator, and surface

Characterization of Fibre-Direction Dependent Damping of Glass-Fibre Composites at Low Temperatures and Low Frequencies

DEFF Research Database (Denmark)

Kliem, Mathias; Høgsberg, Jan Becker; Dannemann, Martin

2016-01-01

This paper deals with the characterization of the fibre-direction dependent damping capability of glass fibre reinforced plastics (GFRP) to be used in electrical power transmission pylons. A fibre-direction dependent damping analysis of unidirectional (UD) GFRP samples was carried out using...... a Dynamic Mechanical Analysis (DMA) for five different fibre orientations (0˚ | 30˚ | 45˚ | 60˚ and 90˚) and two different matrix systems (epoxy and a vinyl ester resin). Based on the dynamic characteristics the damping performance of the various composite materials was studied at three temperatures (-10˚C......, 0˚C and 10˚C) and three vibration frequencies (1 Hz, 10 Hz and 30 Hz). It was observed that the loss factor of Glass Fibre Reinforced Vinyl-Ester (GF-VE) was in general slightly higher compared to the Glass Fibre Reinforced Epoxy (GF-EP). The loss factor increased slightly with temperature, while...

A study of the effect of the position of an edge filter within a ratiometric wavelength measurement system

International Nuclear Information System (INIS)

Wu, Qiang; Wang, Pengfei; Semenova, Yuliya; Farrell, Gerald

2010-01-01

The effect of the position of an edge filter within a ratiometric wavelength measurement system was investigated based on three cases: (1) the reflected fibre Bragg grating (FBG) signal passes through both the reference arm and the edge filter arm, (2) the reflected FBG signal is connected directly to the edge filter arm and does not pass through the reference arm, (3) the edge filter sits in line with the FBG and thus the source power is filtered prior to reaching the FBG. Both numerical simulations and experimental results show that cases 1 and 2 have similar system performance whilst case 3 is the best arrangement which offers the highest wavelength resolution

Methodology for characterisation of glass fibre composite architecture

DEFF Research Database (Denmark)

Hansen, Jens Zangenberg; Larsen, J.B.; Østergaard, R.C.

2012-01-01

of the fibres. The information is used for different analyses to investigate and characterise the fibre architecture. As an example, the methodology is applied to glass fibre reinforced composites with varying fibre contents. The different fibre volume fractions (FVFs) affect the number of contact points per......The present study outlines a methodology for microstructural characterisation of fibre reinforced composites containing circular fibres. Digital micrographs of polished cross-sections are used as input to a numerical image processing tool that determines spatial mapping and radii detection...... fibre, the communal fibre distance and the local FVF. The fibre diameter distribution and packing pattern remain somewhat similar for the considered materials. The methodology is a step towards a better understanding of the composite microstructure and can be used to evaluate the interconnection between...

CONFERENCE NOTE: CETO—Centro de Ciências e Tecnologias Opticas, Trends in Optical Fibre Metrology and Standards

Science.gov (United States)

1994-01-01

requirements of the new generation of analogue and digital fibre optical systems, which require sophisticated measurement techniques employing complex instruments unique to optical measurements. The school will foster and enhance the interaction between material, devices, systems, and standards-oriented R&D communities, as well as between engineers concerned with design and manufacturers of systems and instrumentation. Topics Review of optical fibre communication technology and systems Measurement techniques for fibre characterization: Reliability and traceability Reference fibres and calibration artefacts Ribbon fibres Mechanical and environmental testing Fibre reliability Polarimetric measurements Passive components characterization: Splices and connectors Couplers, splitters, taps and WDMs Optical fibres and isolators WDM technologies and applications: WDM technologies Tunable optical filters Fibre amplifiers and sources: Performances and characterization Design and standards Nonlinear effects Subsystem design and standards: Design and fabrication techniques Performance degradation and reliability Evaluation of costs/performance/technology Sensors IR - optical fibres Plastic fibres Instrumentation Registration Participation free of charge for postgraduate students, with some grants available for travel and lodging expenses. All correspondence should be addressed to: Secretariat, Trends in Optical Fibre Metrology and Standards, a/c Prof. Olivério D D Soares, Centro de Ciências e Tecnologias Opticas, Lab. Fisica - Faculdade de Ciências, Praça Gomes Teixeira, P-4000 Porto, Portugal. Tel: 351-2-310290, 351-2-2001648; Fax: 351-2-319267.

Mechanical, degradation and cytocompatibility properties of magnesium coated phosphate glass fibre reinforced polycaprolactone composites.

Science.gov (United States)

Liu, Xiaoling; Hasan, Muhammad S; Grant, David M; Harper, Lee T; Parsons, Andrew J; Palmer, Graham; Rudd, Chris D; Ahmed, Ifty

2014-11-01

Retention of mechanical properties of phosphate glass fibre reinforced degradable polyesters such as polycaprolactone and polylactic acid in aqueous media has been shown to be strongly influenced by the integrity of the fibre/polymer interface. A previous study utilising 'single fibre' fragmentation tests found that coating with magnesium improved the fibre and matrix interfacial shear strength. Therefore, the aim of this study was to investigate the effects of a magnesium coating on the manufacture and characterisation of a random chopped fibre reinforced polycaprolactone composite. Short chopped strand non-woven phosphate glass fibre mats were sputter coated with degradable magnesium to manufacture phosphate glass fibre/polycaprolactone composites. The degradation behaviour (water uptake, mass loss and pH change of the media) of these polycaprolactone composites as well as of pure polycaprolactone was investigated in phosphate buffered saline. The Mg coated fibre reinforced composites revealed less water uptake and mass loss during degradation compared to the non-coated composites. The cations released were also explored and a lower ion release profile for all three cations investigated (namely Na(+), Mg(2+) and Ca(2+)) was seen for the Mg coated composite samples. An increase of 17% in tensile strength and 47% in tensile modulus was obtained for the Mg coated composite samples. Both flexural and tensile properties were investigated and a higher retention of mechanical properties was obtained for the Mg coated fibre reinforced composite samples up to 10 days immersion in PBS. Cytocompatibility study showed both composite samples (coated and non-coated) had good cytocompatibility with human osteosarcoma cell line. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Fibres and energy from wheat straw by simple practice

Energy Technology Data Exchange (ETDEWEB)

Leponiemi, A.

2011-06-15

to store wheat straw chemically with formic acid-based chemicals over a year without significant changes in the chemical composition. The chemical storage can be integrated with the suggested chemical or mechanical defibration process, soda pulping process or any other process utilising non-wood fibres. In China, a clear demand for nonwood- based fibres exists due to a shortage of fibre and also because of the increasing demand for bioenergy. In Europe, the competitiveness of non-wood fibre utilisation will only be established if combined with energy production. (orig.)

Biological durability and oxidative potential of a stonewool mineral fibre compared to crocidolite asbestos fibres

Energy Technology Data Exchange (ETDEWEB)

Hippeli, S. [Lehrstuhl fuer Phytopathologie, Labor fuer Biochemische Toxikologie, Technische Universitaet Muenchen-Weihenstephan, D-85350 Freising-Weihenstephan (Germany); Dornisch, K. [Lehrstuhl fuer Phytopathologie, Labor fuer Biochemische Toxikologie, Technische Universitaet Muenchen-Weihenstephan, D-85350 Freising-Weihenstephan (Germany); Kaiser, S. [Lehrstuhl fuer Phytopathologie, Labor fuer Biochemische Toxikologie, Technische Universitaet Muenchen-Weihenstephan, D-85350 Freising-Weihenstephan (Germany); Draeger, U. [Deutsche Rockwool Mineralwoll GmbH, Karl-Schneider-Strasse 14-18, D-45966 Gladbeck (Germany); Elstner, E.F. [Lehrstuhl fuer Phytopathologie, Labor fuer Biochemische Toxikologie, Technische Universitaet Muenchen-Weihenstephan, D-85350 Freising-Weihenstephan (Germany)

1997-07-01

Experiments are described concerning the differences in redox properties and biodurability of natural asbestos fibres and an experimental stonewool fibre incubated in Gamble solution and reconstructed surfactant fluid. Crocidolite exhibits a significantly higher oxidative potential compared to the tested stonewool fibres. The oxidative acitivity of both types of fibres is not constant during incubation over several weeks, but rather shows a sinoidal curve including reactivities much higher than those at the beginning of the incubation. A continuous loss of mass is concluded not to be definitively connected with a continuous loss of toxicity. (orig.). With 1 fig.

Review article: dietary fibre-microbiota interactions.

Science.gov (United States)

Simpson, H L; Campbell, B J

2015-07-01

Application of modern rapid DNA sequencing technology has transformed our understanding of the gut microbiota. Diet, in particular plant-based fibre, appears critical in influencing the composition and metabolic activity of the microbiome, determining levels of short-chain fatty acids (SCFAs) important for intestinal health. To assess current epidemiological, experimental and clinical evidence of how long-term and short-term alterations in dietary fibre intake impact on the microbiome and metabolome. A Medline search including items 'intestinal microbiota', 'nutrition', 'diet', 'dietary fibre', 'SCFAs' and 'prebiotic effect' was performed. Studies found evidence of fibre-influenced differences in the microbiome and metabolome as a consequence of habitual diet, and of long-term or short-term intervention (in both animals and humans). Agrarian diets high in fruit/legume fibre are associated with greater microbial diversity and a predominance of Prevotella over Bacteroides. 'Western'-style diets, high in fat/sugar, low in fibre, decrease beneficial Firmicutes that metabolise dietary plant-derived polysaccharides to SCFAs and increase mucosa-associated Proteobacteria (including enteric pathogens). Short-term diets can also have major effects, particularly those exclusively animal-based, and those high-protein, low-fermentable carbohydrate/fibre 'weight-loss' diets, increasing the abundance of Bacteroides and lowering Firmicutes, with long-term adherence to such diets likely increasing risk of colonic disease. Interventions to prevent intestinal inflammation may be achieved with fermentable prebiotic fibres that enhance beneficial Bifidobacteria or with soluble fibres that block bacterial-epithelial adherence (contrabiotics). These mechanisms may explain many of the differences in microbiota associated with long-term ingestion of a diet rich in fruit and vegetable fibre. © 2015 The Authors. Alimentary Pharmacology & Therapeutics published by John Wiley & Sons Ltd.

Sky subtraction at the Poisson limit with fibre-optic multiobject spectroscopy

Science.gov (United States)

Sharp, R.; Parkinson, H.

2010-11-01

We report on the limitations of sky-subtraction accuracy for long-duration fibre-optic multiobject spectroscopy of faint astronomical sources during long-duration exposures. We show that while standard sky subtraction techniques yield accuracies consistent with the Poisson noise limit for exposures of 1h duration, there are large-scale systematic defects that inhibit the sensitivity gains expected on the summation of longer duration exposures. For the AAOmega system at the Anglo-Australian Telescope, we identify a limiting systematic sky-subtraction accuracy, which is reached after integration times of 4-10h. We show that these systematic defects can be avoided through the use of the fibre nod-and-shuffle (N+S) observing mode, but with a potential cost in observing efficiency. Finally, we demonstrate that these disadvantages can be overcome through the application of a Principal Components Analysis (PCA) sky-subtraction routine. Such an approach minimize systematic residuals across long-duration exposures, allowing deep integrations. We apply the PCA approach to over 200h of on-sky observations and conclude that for the AAOmega system, the residual error in long-duration observations falls at a rate proportional to τ-0.32 in contrast to the τ-0.5 rate expected from theoretical considerations. With this modest rate of decline, the PCA approach represents a more efficient mode of observation than the N+S technique for observations in the sky limited regime with durations of 10-100h (even before accounting for the additional signal-to-noise ratio and targeting efficiency losses often associated with the N+S technique). This conclusion has important implications for the observing strategies of the next generation of fibre-optics redshift surveys with existing facilities as well as design implications for fibre-optic systems destined for new facilities. It argues against the use of the inherently inefficient N+S technique for faint object fibre-optic survey

Balanced microwave filters

CERN Document Server

Hong, Jiasheng; Medina, Francisco; Martiacuten, Ferran

2018-01-01

This book presents and discusses strategies for the design and implementation of common-mode suppressed balanced microwave filters, including, narrowband, wideband, and ultra-wideband filters This book examines differential-mode, or balanced, microwave filters by discussing several implementations of practical realizations of these passive components. Topics covered include selective mode suppression, designs based on distributed and semi-lumped approaches, multilayer technologies, defect ground structures, coupled resonators, metamaterials, interference techniques, and substrate integrated waveguides, among others. Divided into five parts, Balanced Microwave Filters begins with an introduction that presents the fundamentals of balanced lines, circuits, and networks. Part 2 covers balanced transmission lines with common-mode noise suppression, including several types of common-mode filters and the application of such filters to enhance common-mode suppression in balanced bandpass filters. Next, Part 3 exa...

Dietary fibre in foods: a review.

Science.gov (United States)

Dhingra, Devinder; Michael, Mona; Rajput, Hradesh; Patil, R T

2012-06-01

Dietary fibre is that part of plant material in the diet which is resistant to enzymatic digestion which includes cellulose, noncellulosic polysaccharides such as hemicellulose, pectic substances, gums, mucilages and a non-carbohydrate component lignin. The diets rich in fibre such as cereals, nuts, fruits and vegetables have a positive effect on health since their consumption has been related to decreased incidence of several diseases. Dietary fibre can be used in various functional foods like bakery, drinks, beverages and meat products. Influence of different processing treatments (like extrusion-cooking, canning, grinding, boiling, frying) alters the physico- chemical properties of dietary fibre and improves their functionality. Dietary fibre can be determined by different methods, mainly by: enzymic gravimetric and enzymic-chemical methods. This paper presents the recent developments in the extraction, applications and functions of dietary fibre in different food products.

Photon harvesting, coloring and polarizing in photovoltaic cell integrated color filters: efficient energy routing strategies for power-saving displays.

Science.gov (United States)

Wen, Long; Chen, Qin; Song, Shichao; Yu, Yan; Jin, Lin; Hu, Xin

2015-07-03

We describe the integral electro-optical strategies that combine the functionalities of photovoltaic (PV) electricity generation and color filtering as well as polarizing to realize more efficient energy routing in display technology. Unlike the conventional pigment-based filters and polarizers, which absorb substantial amounts of unwanted spectral components and dissipate them in the form of heat, we propose converting the energy of those photons into electricity by constructing PV cell-integrated color filters based on a selectively transmitting aluminum (Al) rear electrode perforated with nanoholes (NHs). Combining with a dielectric-metal-dielectric (DMD) front electrode, the devices were optimized to enable efficient cavity-enhanced photon recycling in the PV functional layers. We perform a comprehensive theoretical and numerical analysis to explore the extraordinary optical transmission (EOT) through the Al NHs and identify basic design rules for achieving structural coloring or polarizing in our PV color filters. We show that the addition of thin photoactive polymer layers on the symmetrically configured Al NH electrode narrows the bandwidth of the EOT-assisted high-pass light filtering due to the strongly damped anti-symmetric coupling of the surface modes excited on the front and rear surface of the Al NHs, which facilitates the whole visible coloring with relatively high purity for the devices. By engineering the cut-off characteristics of the plasmonic waveguide mode supported by the circular or ellipsoidal Al NHs, beyond the photon recycling capacity, PV color filters and PV polarizing color filters that allow polarization-insensitive and strong polarization-anisotropic color filtering were demonstrated. The findings presented here may shed some light on expanding the utilization of PV electricity generation across new-generation energy-saving electrical display devices.

Laser–fibre vibrometry at 1550 nm

International Nuclear Information System (INIS)

Waz, A T; Kaczmarek, P R; Abramski, K M

2009-01-01

This paper presents new solutions for laser vibrometry, which are based on fibre vibrometry in the third telecommunication window. The scattered laser beam from a vibrating object is guided by a fibre collimator and coherently detected through heterodyning it with an acousto-optical frequency-shifted reference beam. The concept of measuring vibration parameters from many points of the vibrating object has been inspired by wavelength division multiplexing (WDM) in fibre telecommunications. The N-independent WDM separated 15XX nm fibre-coupled laser diodes (used for optical fibre telecommunications) form a system of sources for multipoint vibration measurement according to the rule 'one wavelength–one point'

Microanalytical investigation of fibre-reinforced ceramic materials

International Nuclear Information System (INIS)

Meier, B.; Grathwohl, G.

1989-01-01

Microanalytical investigations have been made on samples of ceramic fibres (SiC fibres, (Nicalon) C fibre coated with TiN) and fibre-reinforced ceramics (SiC-and glass-matrices). High resolution Auger electron spectroscopy (HRAES), electron probe microanalysis (EPMA) and scanning electron microscopy were employed for these examinations. Analysis was best performed with HRAES on account of its lateral and depth resolution. Some of the problems involved in this technique are discussed e.g. electron beam effects. AES depth profiles of ceramic fibres are reported and compared with the surface analysis of fibres in the composites after being broken in situ. (orig.)

Sub-micrometre accurate free-form optics by three-dimensional printing on single-mode fibres

Science.gov (United States)

Gissibl, Timo; Thiele, Simon; Herkommer, Alois; Giessen, Harald

2016-01-01

Micro-optics are widely used in numerous applications, such as beam shaping, collimation, focusing and imaging. We use femtosecond 3D printing to manufacture free-form micro-optical elements. Our method gives sub-micrometre accuracy so that direct manufacturing even on single-mode fibres is possible. We demonstrate the potential of our method by writing different collimation optics, toric lenses, free-form surfaces with polynomials of up to 10th order for intensity beam shaping, as well as chiral photonic crystals for circular polarization filtering, all aligned onto the core of the single-mode fibres. We determine the accuracy of our optics by analysing the output patterns as well as interferometrically characterizing the surfaces. We find excellent agreement with numerical calculations. 3D printing of microoptics can achieve sufficient performance that will allow for rapid prototyping and production of beam-shaping and imaging devices. PMID:27339700

A viscoelastic-viscoplastic model for short-fibre reinforced polymers with complex fibre orientations

Directory of Open Access Journals (Sweden)

Nciri M.

2015-01-01

Full Text Available This paper presents an innovative approach for the modelling of viscous behaviour of short-fibre reinforced composites (SFRC with complex distributions of fibre orientations and for a wide range of strain rates. As an alternative to more complex homogenisation methods, the model is based on an additive decomposition of the state potential for the computation of composite’s macroscopic behaviour. Thus, the composite material is seen as the assembly of a matrix medium and several linear elastic fibre media. The division of short fibres into several families means that complex distributions of orientation or random orientation can be easily modelled. The matrix behaviour is strain-rate sensitive, i.e. viscoelastic and/or viscoplastic. Viscoelastic constitutive laws are based on a generalised linear Maxwell model and the modelling of the viscoplasticity is based on an overstress approach. The model is tested for the case of a polypropylene reinforced with short-glass fibres with distributed orientations and subjected to uniaxial tensile tests, in different loading directions and under different strain rates. Results demonstrate the efficiency of the model over a wide range of strain rates.

Hollow nanocrystals and method of making

Science.gov (United States)

Alivisatos, A Paul [Oakland, CA; Yin, Yadong [Moreno Valley, CA; Erdonmez, Can Kerem [Berkeley, CA

2011-07-05

Described herein are hollow nanocrystals having various shapes that can be produced by a simple chemical process. The hollow nanocrystals described herein may have a shell as thin as 0.5 nm and outside diameters that can be controlled by the process of making.

Study on The Effectiveness of Egg Tray and Coir Fibre as A Sound Absorber

Science.gov (United States)

Kaamin, Masiri; Farah Atiqah Ahmad, Nor; Ngadiman, Norhayati; Kadir, Aslila Abdul; Razali, Siti Nooraiin Mohd; Mokhtar, Mardiha; Sahat, Suhaila

2018-03-01

Sound or noise pollution has become one major issues to the community especially those who lived in the urban areas. It does affect the activity of human life. This excessive noise is mainly caused by machines, traffic, motor vehicles and also any unwanted sounds that coming from outside and even from the inside of the building. Such as a loud music. Therefore, the installation of sound absorption panel is one way to reduce the noise pollution inside a building. The selected material must be a porous and hollow in order to absorb high frequency sound. This study was conducted to evaluate the potential of egg tray and coir fibre as a sound absorption panel. The coir fibre has a good coefficient value which make it suitable as a sound absorption material and can replace the traditional material; syntactic and wooden material. The combination of pyramid shape of egg tray can provide a large surface for uniform sound reflection. This study was conducted by using a panel with size 1 m x 1 m with a thickness of 6 mm. This panel consist of egg tray layer, coir fibre layer and a fabric as a wrapping for the aesthetic value. Room reverberation test has been carried to find the loss of reverberation time (RT). Result shows that, a reverberation time reading is on low frequency, which is 125 Hz to 1600 Hz. Within these frequencies, this panel can shorten the reverberation time of 5.63s to 3.60s. Hence, from this study, it can be concluded that the selected materials have the potential as a good sound absorption panel. The comparison is made with the previous research that used egg tray and kapok as a sound absorption panel.

Study on The Effectiveness of Egg Tray and Coir Fibre as A Sound Absorber

Directory of Open Access Journals (Sweden)

Kaamin Masiri

2018-01-01

Full Text Available Sound or noise pollution has become one major issues to the community especially those who lived in the urban areas. It does affect the activity of human life. This excessive noise is mainly caused by machines, traffic, motor vehicles and also any unwanted sounds that coming from outside and even from the inside of the building. Such as a loud music. Therefore, the installation of sound absorption panel is one way to reduce the noise pollution inside a building. The selected material must be a porous and hollow in order to absorb high frequency sound. This study was conducted to evaluate the potential of egg tray and coir fibre as a sound absorption panel. The coir fibre has a good coefficient value which make it suitable as a sound absorption material and can replace the traditional material; syntactic and wooden material. The combination of pyramid shape of egg tray can provide a large surface for uniform sound reflection. This study was conducted by using a panel with size 1 m x 1 m with a thickness of 6 mm. This panel consist of egg tray layer, coir fibre layer and a fabric as a wrapping for the aesthetic value. Room reverberation test has been carried to find the loss of reverberation time (RT. Result shows that, a reverberation time reading is on low frequency, which is 125 Hz to 1600 Hz. Within these frequencies, this panel can shorten the reverberation time of 5.63s to 3.60s. Hence, from this study, it can be concluded that the selected materials have the potential as a good sound absorption panel. The comparison is made with the previous research that used egg tray and kapok as a sound absorption panel.

Formation of Uniform Hollow Silica microcapsules

Science.gov (United States)

Yan, Huan; Kim, Chanjoong

2013-03-01

Microcapsules are small containers with diameters in the range of 0.1 - 100 μm. Mesoporous microcapsules with hollow morphologies possess unique properties such as low-density and high encapsulation capacity, while allowing controlled release by permeating substances with a specific size and chemistry. Our process is a one-step fabrication of monodisperse hollow silica capsules with a hierarchical pore structure and high size uniformity using double emulsion templates obtained by the glass-capillary microfluidic technique to encapsulate various active ingredients. These hollow silica microcapsules can be used as biomedical applications such as drug delivery and controlled release.

Microring embedded hollow polymer fiber laser

Energy Technology Data Exchange (ETDEWEB)

Linslal, C. L., E-mail: linslal@gmail.com; Sebastian, S.; Mathew, S.; Radhakrishnan, P.; Nampoori, V. P. N.; Girijavallabhan, C. P.; Kailasnath, M. [International School of Photonics, Cochin University of Science and Technology, Cochin 22 (India)

2015-03-30

Strongly modulated laser emission has been observed from rhodamine B doped microring resonator embedded in a hollow polymer optical fiber by transverse optical pumping. The microring resonator is fabricated on the inner wall of a hollow polymer fiber. Highly sharp lasing lines, strong mode selection, and a collimated laser beam are observed from the fiber. Nearly single mode lasing with a side mode suppression ratio of up to 11.8 dB is obtained from the strongly modulated lasing spectrum. The microring embedded hollow polymer fiber laser has shown efficient lasing characteristics even at a propagation length of 1.5 m.

Fractional order integration and fuzzy logic based filter for denoising of echocardiographic image.

Science.gov (United States)

Saadia, Ayesha; Rashdi, Adnan

2016-12-01

Ultrasound is widely used for imaging due to its cost effectiveness and safety feature. However, ultrasound images are inherently corrupted with speckle noise which severely affects the quality of these images and create difficulty for physicians in diagnosis. To get maximum benefit from ultrasound imaging, image denoising is an essential requirement. To perform image denoising, a two stage methodology using fuzzy weighted mean and fractional integration filter has been proposed in this research work. In stage-1, image pixels are processed by applying a 3 × 3 window around each pixel and fuzzy logic is used to assign weights to the pixels in each window, replacing central pixel of the window with weighted mean of all neighboring pixels present in the same window. Noise suppression is achieved by assigning weights to the pixels while preserving edges and other important features of an image. In stage-2, the resultant image is further improved by fractional order integration filter. Effectiveness of the proposed methodology has been analyzed for standard test images artificially corrupted with speckle noise and real ultrasound B-mode images. Results of the proposed technique have been compared with different state-of-the-art techniques including Lsmv, Wiener, Geometric filter, Bilateral, Non-local means, Wavelet, Perona et al., Total variation (TV), Global Adaptive Fractional Integral Algorithm (GAFIA) and Improved Fractional Order Differential (IFD) model. Comparison has been done on quantitative and qualitative basis. For quantitative analysis different metrics like Peak Signal to Noise Ratio (PSNR), Speckle Suppression Index (SSI), Structural Similarity (SSIM), Edge Preservation Index (β) and Correlation Coefficient (ρ) have been used. Simulations have been done using Matlab. Simulation results of artificially corrupted standard test images and two real Echocardiographic images reveal that the proposed method outperforms existing image denoising techniques

Tungsten fibre-reinforced composites for advanced plasma facing components

Directory of Open Access Journals (Sweden)

R. Neu

2017-08-01

Full Text Available The European Fusion Roadmap foresees water cooled plasma facing components in a first DEMO design in order to provide enough margin for the cooling capacity and to only moderately extrapolate the technology which was developed and tested for ITER. In order to make best use of the water cooling concept copper (Cu and copper-chromium-zirconium alloy (CuCrZr are envisaged as heat sink whereas as armour tungsten (W based materials will be used. Combining both materials in a high heat flux component asks for an increase of their operational range towards higher temperature in case of Cu/CuCrZr and lower temperatures for W. A remedy for both issues- brittleness of W and degrading strength of CuCrZr- could be the use of W fibres (Wf in W and Cu based composites. Fibre preforms could be manufactured with industrially viable textile techniques. Flat textiles with a combination of 150/70 µm W wires have been chosen for layered deposition of tungsten-fibre reinforced tungsten (Wf/W samples and tubular multi-layered braidings with W wire thickness of 50 µm were produced as a preform for tungsten-fibre reinforced copper (Wf /Cu tubes. Cu melt infiltration was performed together with an industrial partner resulting in sample tubes without any blowholes. Property estimation by mean field homogenisation predicts strongly enhanced strength of the Wf/CuCrZr composite compared to its pure CuCrZr counterpart. Wf /W composites show very high toughness and damage tolerance even at room temperature. Cyclic load tests reveal that the extrinsic toughening mechanisms counteracting the crack growth are active and stable. FEM simulations of the Wf/W composite suggest that the influence of fibre debonding, which is an integral part of the toughening mechanisms, and reduced thermal conductivity of the fibre due to the necessary interlayers do not strongly influence the thermal properties of future components.

POLARISATION PRESERVING OPTICAL FIBRE

DEFF Research Database (Denmark)

2000-01-01

. This cladding structure provides polarisation preserving properties to the optical fibre. Optical fibres using this technology may have claddings with elements placed non-periodically as well as in a two-dimensional periodic lattice - such as cladding providing Photonic Band Gap (PBG) effects....

SU-F-BRA-03: Integrating Novel Electromagnetic Tracking Hollow Needle Assistance in Permanent Implant Brachytherapy Procedures

Energy Technology Data Exchange (ETDEWEB)

Racine, E; Hautvast, G; Binnekamp, D [Philips Group Innovation - Biomedical Systems, Eindhoven (Netherlands); Beaulieu, L [Centre Hospitalier Univ de Quebec, Quebec, QC (Canada)

2015-06-15

Purpose: To report on the results of a complete permanent implant brachytherapy procedure assisted by an electromagnetic (EM) hollow needle possessing both 3D tracking and seed drop detection abilities. Methods: End-to-end in-phantom EM-assisted LDR procedures were conducted. The novel system consisted of an EM tracking apparatus (NDI Aurora V2, Planar Field Generator), a 3D US scanner (Philips CX50), a hollow needle prototype allowing 3D tracking and seed drop detection and a specially designed treatment planning software (Philips Healthcare). A tungsten-doped 30 cc spherical agarose prostate immersed in gelatin was used for the treatment. A cylindrical shape of 0.8 cc was carved along its diameter to mimic the urethra. An initial plan of 26 needles and 47 seeds was established with the system. The plan was delivered with the EM-tracked hollow needle, and individual seed drop locations were recorded on the fly. The phantom was subsequently imaged with a CT scanner from which seed positions and contour definitions were obtained. The DVHs were then independently recomputed and compared with those produced by the planning system, both before and after the treatment. Results: Of the 47 seeds, 45 (96%) were detected by the EM technology embedded in the hollow needle design. The executed plan (from CT analysis) differed from the initial plan by 2%, 14% and 8% respectively in terms of V100, D90 and V150 for the prostate, and by 8%, 7% and 10% respectively in terms of D5, V100 and V120 for the urethra. Conclusion: The average DVH deviations between initial and executed plans were within a 5% tolerance imposed for this proof-of-concept assessment. This relatively good concordance demonstrates the feasibility and potential benefits of combining EM tracking and seed drop detection for real-time dosimetry validation and assistance in permanent implant brachytherapy procedures. This project has been entirely funded by Philips Healthcare.

Angiogenic effect induced by mineral fibres

International Nuclear Information System (INIS)

Carbonari, Damiano; Campopiano, Antonella; Ramires, Deborah; Strafella, Elisabetta; Staffolani, Sara; Tomasetti, Marco; Curini, Roberta; Valentino, Matteo; Santarelli, Lory; Amati, Monica

2011-01-01

Highlights: → In this study we described the angiogenetic effect of some mineral fibres. → Wollastonite fibres induce blood vessel formation. → The size and shape of the fibres were important factors for the cell signalling. → Wollastonite induce ROS-NFκB activation and EGFR signalling. → Involvement of wollastonite exposure in the development of pathological conditions. -- Abstract: Due to the toxic effect of asbestos, other materials with similar chemical-physical characteristics have been introduced to substitute it. We evaluate the angiogenic effect of certain asbestos substitute fibres such as glass fibres (GFs), ceramic fibres (CFs) and wollastonite fibres (WFs) and then compare angiogenic responses to those induced by crocidolite asbestos fibres (AFs). An in vitro model using human endothelial cells in small islands within a culture matrix of fibroblasts (Angio-Kit) was used to evaluate vessel formation. The release of IL-6, sIL-R6, IL-8, VEGF-A and their soluble receptors, sVEGFR-1, sVEGFR-2, was determined in the conditioning medium of Angio-Kit system after fibre treatment. ROS formation and cell viability were evaluated in cultured endothelial cells (HUVEC). To evaluate the involvement of intracellular mechanisms, EGFR signalling, ROS formation and nuclear factor-κB (NFκB) pathway were then inhibited by incubating HUVEC cells with AG1478, NAC and PDTC respectively, and the cytokine and growth factor release was analyzed in the culture medium after 7 days of fibre incubation. Among the mineral fibres tested, WFs markedly induced blood vessel formation which was associated with release of IL-6 and IL-8, VEGF-A and their soluble receptors. ROS production was observed in HUVEC after WFs treatment which was associated with cell cytotoxicity. The EGFR-induced ERK phosphorylation and ROS-mediated NFκB activation were involved in the cytokine and angiogenic factor release. However, only the EGFR activation was able to induce angiogenesis. The WFs

Action of trypsin on structural changes of collagen fibres from sea cucumber (Stichopus japonicus).

Science.gov (United States)

Liu, Zi-Qiang; Tuo, Feng-Yan; Song, Liang; Liu, Yu-Xin; Dong, Xiu-Ping; Li, Dong-Mei; Zhou, Da-Yong; Shahidi, Fereidoon

2018-08-01

Trypsin, a representative serine proteinase, was used to hydrolyse the collagen fibres from sea cucumber (Stichopus japonicus) to highlight the role of serine proteinase in the autolysis of sea cucumber. Partial disaggregation of collagen fibres into collagen fibrils upon trypsin treatment occurred. The trypsin treatment also caused a time-dependent release of water-soluble glycosaminoglycans and proteins. Therefore, the degradation of the proteoglycan bridges between collagen fibrils might account for the disaggregation of collagen fibrils. For trypsin-treated collagen fibres (72 h), the collagen fibrils still kept their structural integrity and showed characteristic D-banding pattern, and the dissolution rate of hydroxyproline was just 0.21%. Meanwhile, Fourier transform infrared analysis showed the collagen within trypsin-treated collagen fibres (72 h) still retaining their triple-helical conformation. These results suggested that serine proteinase participated in the autolysis of S. japonicus body wall by damaging the proteoglycan bridges between collagen fibrils and disintegrating the latter. Copyright © 2018 Elsevier Ltd. All rights reserved.

Frost resistance of fibre reinforced concrete structures

DEFF Research Database (Denmark)

Hansen, Ernst Jan De Place

1999-01-01

Frost resistance of fibre reinforced concrete with 2.5-4.2% air and 6-9% air (% by volume in fresh concrete) casted in the laboratory and in-situ is compared. Steel fibres with hooked ends (ZP, length 30 mm) and polypropylene fibres (PP, CS, length 12 mm) are applied. It is shown that· addition...... of 0.4-1% by volume of fibres cannot replace air entrainment in order to secure a frost resistant concrete; the minimum amount of air needed to make the concrete frost resistant is not changed when adding fibres· the amount of air entrainment must be increased when fibres are added to establish...

Comparison of testing methods for particulate filters

International Nuclear Information System (INIS)

Ullmann, W.; Przyborowski, S.

1983-01-01

Four testing methods for particulate filters were compared by using the test rigs of the National Board of Nuclear Safety and Radiation Protection: 1) Measurement of filter penetration P as a function of particle size d by using a polydisperse NaC1 test aerosol and a scintillation particle counter; 2) Modified sodium flame test for measurement of total filter penetration P for various polydisperse NaC1 test aerosols; 3) Measurement of total filter penetration P for a polydisperse NaC1 test aerosol labelled with short-lived radon daughter products; 4) Measurement of total filter penetration P for a special paraffin oil test aerosol (oil fog test used in FRG according DIN 24 184, test aerosol A). The investigations were carried out on sheets of glass fibre paper (five grades of paper). Detailed information about the four testing methods and the used particle size distributions is given. The different results of the various methods are the base for the discussion of the most important parameters which influence the filter penetration P. The course of the function P=f(d) shows the great influence of the particle size. As expected there was also found a great dependence both from the test aerosol as well as from the principle and the measuring range of the aerosol-measuring device. The differences between the results of the various test methods are greater the lower the penetration. The use of NaCl test aerosol with various particle size distributions gives great differences for the respective penetration values. On the basis of these results and the values given by Dorman conclusions are made about the investigation of particulate filters both for the determination of filter penetration P as well as for the leak test of installed filters

Interfacial fracture of the fibre-metal laminates based on fibre reinforced thermoplastics

International Nuclear Information System (INIS)

Abdullah, M.R.; Prawoto, Y.; Cantwell, W.J.

2015-01-01

As the adhesion quality plays an important role in determining the mechanical performance and environmental stability of most types of fibre-metal laminates (FMLs), investigating the interfacial fracture properties becomes one of the key factors for the improvement. Adhesion of a self-reinforced polypropylene (SRPP) and glass fibre reinforced polypropylene (GFPP) based FML is evaluated experimentally. Single Cantilever Beam (SCB) tests were performed to access interfacial fracture energy (G c ) of the bi-material laminates and their associated interlayer materials. Simulations mimicking the experiments were also performed. The energy needed to fracture was obtained experimentally and also via stress intensity factor from the simulations. The test results show that good adhesion between the aluminium and fibre reinforced thermoplastics can be achieved using a sulphuric acid anodising surface pre-treatment. Further examination has shown that the edges of the test samples highlighted the presence of significant fibre bridging in the SRPP and plastics deformation in the GFPP. - Highlights: • Adhesion of a self-reinforced polypropylene and glass fibre reinforced polypropylene is evaluated. • Single Cantilever Beam tests were performed to access interfacial fracture energy. • The energy needed to fracture was obtained experimentally and also via stress intensity factor from the simulations. • The test results show that best adhesion is achieved using a sulphuric acid anodizing surface pre-treatment

Laser self-mixing interference fibre sensor

International Nuclear Information System (INIS)

Zhu Jun; Zhao Yan; Jin Guofan

2008-01-01

Fibre sensors exhibit a number of advantages over other sensors such as high sensitivity, electric insulation, corrosion resistance, interference rejection and so on. And laser self-mixing interference can accurately detect the phase difference of feedback light. In this paper, a novel laser self-mixing interference fibre sensor that combines the advantages of fibre sensors with those of laser self-mixing interference is presented. Experimental configurations are set up to study the relationship between laser power output and phase of laser feedback light when the fibre trembles or when the fibre is stretched or pressed. The theoretical analysis of pressure sensors based on laser self-mixing interference is indicated to accord with the experimental results. (classical areas of phenomenology)

Space Charge Mitigation With Longitudinally Hollow Bunches

CERN Multimedia

Oeftiger, Adrian; Rumolo, Giovanni

2016-01-01

Hollow longitudinal phase space distributions have a flat profile and hence reduce the impact of transverse space charge. Dipolar parametric excitation with the phase loop feedback systems provides such hollow distributions under reproducible conditions. We present a procedure to create hollow bunches during the acceleration ramp of CERN’s PS Booster machine with minimal changes to the operational cycle. The improvements during the injection plateau of the downstream Proton Synchrotron are assessed in comparison to standard parabolic bunches.

Flexible RF filter using a nonuniform SCISSOR.

Science.gov (United States)

Zhuang, Leimeng

2016-03-15

This work presents a flexible radiofrequency (RF) filter using an integrated microwave photonic circuit that comprises a nonuniform side-coupled integrated spaced sequence of resonators (N-SCISSOR). The filter passband can be reconfigured by varying the N-SCISSOR parameters. When employing a dual-parallel Mach-Zechnder modulator, the filter is also able to perform frequency down-conversion. In the experiment, various filter response shapes are shown, ranging from a flat-top band-pass filter to a total opposite high-rejection (>40  dB) notch filter, with a frequency coverage of greater than two octaves. The frequency down-conversion function is also demonstrated.

Calcium binding by dietary fibre

International Nuclear Information System (INIS)

James, W.P.T.; Branch, W.J.; Southgate, D.A.T.

1978-01-01

Dietary fibre from plants low in phytate bound calcium in proportion to its uronic-acid content. This binding by the non-cellulosic fraction of fibre reduces the availability of calcium for small-intestinal absorption, but the colonic microbial digestion of uronic acids liberates the calcium. Thus the ability to maintain calcium balance on high-fibre diets may depend on the adaptive capacity on the colon for calcium. (author)

Hollow nanotubular toroidal polymer microrings.

Science.gov (United States)

Lee, Jiyeong; Baek, Kangkyun; Kim, Myungjin; Yun, Gyeongwon; Ko, Young Ho; Lee, Nam-Suk; Hwang, Ilha; Kim, Jeehong; Natarajan, Ramalingam; Park, Chan Gyung; Sung, Wokyung; Kim, Kimoon

2014-02-01

Despite the remarkable progress made in the self-assembly of nano- and microscale architectures with well-defined sizes and shapes, a self-organization-based synthesis of hollow toroids has, so far, proved to be elusive. Here, we report the synthesis of polymer microrings made from rectangular, flat and rigid-core monomers with anisotropically predisposed alkene groups, which are crosslinked with each other by dithiol linkers using thiol-ene photopolymerization. The resulting hollow toroidal structures are shape-persistent and mechanically robust in solution. In addition, their size can be tuned by controlling the initial monomer concentrations, an observation that is supported by a theoretical analysis. These hollow microrings can encapsulate guest molecules in the intratoroidal nanospace, and their peripheries can act as templates for circular arrays of metal nanoparticles.

Hollow spheres: crucial building blocks for novel nanostructures and nanophotonics

Directory of Open Access Journals (Sweden)

Zhong Kuo

2018-03-01

Full Text Available In this review, we summarize the latest developments in research specifically derived from the unique properties of hollow microspheres, in particular, hollow silica spheres with uniform shells. We focus on applications in nanosphere (colloidal lithography and nanophotonics. The lithography from a layer of hollow spheres can result in nanorings, from a multilayer in unique nano-architecture. In nanophotonics, disordered hollow spheres can result in antireflection coatings, while ordered colloidal crystals (CCs of hollow spheres exhibit unique refractive index enhancement upon infiltration, ideal for optical sensing. Furthermore, whispering gallery mode (WGM inside the shell of hollow spheres has also been demonstrated to enhance light absorption to improve the performance of solar cells. These applications differ from the classical applications of hollow spheres, based only on their low density and large surface area, such as catalysis and chemical sensing. We provide a brief overview of the synthesis and self-assembly approaches of the hollow spheres. We elaborate on their unique optical features leading to defect mode lasing, optomicrofluidics, and the existence of WGMs inside shell for light management. Finally, we provide a perspective on the direction towards which future research relevant to hollow spheres might be directed.

Hollow spheres: crucial building blocks for novel nanostructures and nanophotonics

Science.gov (United States)

Zhong, Kuo; Song, Kai; Clays, Koen

2018-03-01

In this review, we summarize the latest developments in research specifically derived from the unique properties of hollow microspheres, in particular, hollow silica spheres with uniform shells. We focus on applications in nanosphere (colloidal) lithography and nanophotonics. The lithography from a layer of hollow spheres can result in nanorings, from a multilayer in unique nano-architecture. In nanophotonics, disordered hollow spheres can result in antireflection coatings, while ordered colloidal crystals (CCs) of hollow spheres exhibit unique refractive index enhancement upon infiltration, ideal for optical sensing. Furthermore, whispering gallery mode (WGM) inside the shell of hollow spheres has also been demonstrated to enhance light absorption to improve the performance of solar cells. These applications differ from the classical applications of hollow spheres, based only on their low density and large surface area, such as catalysis and chemical sensing. We provide a brief overview of the synthesis and self-assembly approaches of the hollow spheres. We elaborate on their unique optical features leading to defect mode lasing, optomicrofluidics, and the existence of WGMs inside shell for light management. Finally, we provide a perspective on the direction towards which future research relevant to hollow spheres might be directed.

Development of Ultra-High Performance Fibre Reinforced Concrete (UHPFRC) : towards an efficient utilization of binders and fibres

NARCIS (Netherlands)

Yu, R.; Spiesz, P.R.; Brouwers, H.J.H.

2015-01-01

This paper presents a method to develop Ultra-High Performance Fibre Reinforced Concrete (UHPFRC). Towards an efficient utilization of binders and fibres in UHPFRC, the modified Andreasen & Andersen particle packing model and the hybridization design of fibres are utilized. Particularly, the UHPFRC

Fibre optic power meter calibration uncertainties

CSIR Research Space (South Africa)

Nel, M

2010-06-01

Full Text Available the patch cord, alternatively feeding into the standard or UUT is labelled ‘reference patch cord’. It is preferred to use a patch cord with a ceramic fibre tip (not metal fibre tip) to reduce reflections between the fibre tip and the detector... tightening effect To empirically quantify the effect of connector tightening, two readings are taken at each measurement, which for briefness are labelled "tight" and "un-tight". A "tight" connection is when the fibre connector is tightened...

Development of tree hollows in pedunculate oak (Quercus robur)

OpenAIRE

Ranius, Thomas; Niklasson, Mats; Berg, Niclas

2009-01-01

Many invertebrates, birds and mammals are dependent on hollow trees. For landscape planning that aims at persistence of species inhabiting hollow trees it is crucial to understand the development of such trees. In this study we constructed an individual-based simulation model to predict diameter distribution and formation of hollows in oak tree populations. Based on tree-ring data from individual trees, we estimated the ages when hollow formation commences for pedunculate oak (Quercus robur) ...

Effect of Chitosan Binder on Water Absorption of Empty Fruit Bunches Filter Media

International Nuclear Information System (INIS)

Aziatul Niza Sadikin; Mohd Ghazali Mohd Nawawi; Norasikin Othman

2015-01-01

The potential of chitosan as filter media binder was investigated in this study. Chitosan solution with different concentrations were applied to the empty fruit bunches using two different deposition techniques, namely, spray method and addition method. In this study, a water absorption test was used to study the sorption behaviour of empty fruit bunches filter media. The water absorption study showed that the water uptake for empty fruit bunches filter media without the chitosan binder increases with time, until the water sorption reaches the equilibrium state. It was observed that the water uptake decreased from 23 % to 14 % for the chitosan-filled filter media as compared to binder-less filter media, over the duration of 24 hours. For 1 % chitosan concentration, the water uptake is higher compared to 3 % chitosan-filled filter media. The water absorption is relatively lower for filter media with a higher concentration of chitosan due to the high compatibility achieved at this interfacial region between empty fruit bunches fibres and chitosan. Alkali-treated filter media showed the lowest water uptake compared to diethyl ether, ethanol and hot water pretreatment methods. (author)

Rare-Earth Doped Photonic Crystal Fibre Lasers and Amplifiers

DEFF Research Database (Denmark)

Hougaard, Kristian G.

2005-01-01

In this thesis, a theoretical and numerical study of the use of rare-earthdoped photonic crystal fibres as optical amplifiers and lasers, has been performed. Photonic crystal fibres or microstructured optical fibres is a new kind of optical fibre in which the cladding region typically consist....... Their novel properties allow for design of optical fibre amplifiers and fibre lasers with superior performance, compared to solutions based on conventional fibres. The primary applications considered are high efficiency fibre amplifiers based on index guiding photonic crystal fibres, and cladding pumped....... The thesis also presents the basic properties of optical amplification, and describes the numerical model developed to model the behaviour of lasers and amplifiers based on photonic crystal fibres. The developed numerical tools are then used to investigate specific applications of photonic crystal fibres...

Individual hollow and mesoporous aero-graphitic microtube based devices for gas sensing applications

Science.gov (United States)

Lupan, Oleg; Postica, Vasile; Marx, Janik; Mecklenburg, Matthias; Mishra, Yogendra K.; Schulte, Karl; Fiedler, Bodo; Adelung, Rainer

2017-06-01

In this work, individual hollow and mesoporous graphitic microtubes were integrated into electronic devices using a FIB/SEM system and were investigated as gas and vapor sensors by applying different bias voltages (in the range of 10 mV-1 V). By increasing the bias voltage, a slight current enhancement is observed, which is mainly attributed to the self-heating effect. A different behavior of ammonia NH3 vapor sensing by increasing the applied bias voltage for hollow and mesoporous microtubes with diameters down to 300 nm is reported. In the case of the hollow microtube, an increase in the response was observed, while a reverse effect has been noticed for the mesoporous microtube. It might be explained on the basis of the higher specific surface area (SSA) of the mesoporous microtube compared to the hollow one. Thus, at room temperature when the surface chemical reaction rate (k) prevails on the gas diffusion rate (DK) the structures with a larger SSA possess a higher response. By increasing the bias voltage, i.e., the overall temperature of the structure, DK becomes a limiting step in the gas response. Therefore, at higher bias voltages the larger pores will facilitate an enhanced gas diffusion, i.e., a higher gas response. The present study demonstrates the importance of the material porosity towards gas sensing applications.

Method for producing small hollow spheres

International Nuclear Information System (INIS)

Hendricks, C.D.

1979-01-01

A method is described for producing small hollow spheres of glass, metal or plastic, wherein the sphere material is mixed with or contains as part of the composition a blowing agent which decomposes at high temperature (T >approx. 600 0 C). As the temperature is quickly raised, the blowing agent decomposes and the resulting gas expands from within, thus forming a hollow sphere of controllable thickness. The thus produced hollow spheres (20 to 10 3 μm) have a variety of application, and are particularly useful in the fabrication of targets for laser implosion such as neutron sources, laser fusion physics studies, and laser initiated fusion power plants

Fibre failure assessment in carbon fibre reinforced polymers under fatigue loading by synchrotron X-ray computed tomography

OpenAIRE

Garcea, Serafina; Sinclair, Ian; Spearing, Simon

2016-01-01

In situ fatigue experiments using synchrotron X-ray computed tomography (SRCT) are used to assess the underpinning micromechanisms of fibre failure in double notch carbon/epoxy coupons. Observations showed fibre breaks along the 0º ply splits, associated with the presence and failure of bridging fibres, as well as fibres failed in the bulk composite within the 0º plies. A tendency for cluster formation, with multiple adjacent breaks in the bulk composite was observed when higher peak loads we...

Tracking Architecture Based on Dual-Filter with State Feedback and Its Application in Ultra-Tight GPS/INS Integration.

Science.gov (United States)

Zhang, Xi; Miao, Lingjuan; Shao, Haijun

2016-05-02

If a Kalman Filter (KF) is applied to Global Positioning System (GPS) baseband signal preprocessing, the estimates of signal phase and frequency can have low variance, even in highly dynamic situations. This paper presents a novel preprocessing scheme based on a dual-filter structure. Compared with the traditional model utilizing a single KF, this structure avoids carrier tracking being subjected to code tracking errors. Meanwhile, as the loop filters are completely removed, state feedback values are adopted to generate local carrier and code. Although local carrier frequency has a wide fluctuation, the accuracy of Doppler shift estimation is improved. In the ultra-tight GPS/Inertial Navigation System (INS) integration, the carrier frequency derived from the external navigation information is not viewed as the local carrier frequency directly. That facilitates retaining the design principle of state feedback. However, under harsh conditions, the GPS outputs may still bear large errors which can destroy the estimation of INS errors. Thus, an innovative integrated navigation filter is constructed by modeling the non-negligible errors in the estimated Doppler shifts, to ensure INS is properly calibrated. Finally, field test and semi-physical simulation based on telemetered missile trajectory validate the effectiveness of methods proposed in this paper.

Photonic bandpass filter characteristics of multimode SOI waveguides integrated with submicron gratings.

Science.gov (United States)

Sah, Parimal; Das, Bijoy Krishna

2018-03-20

It has been shown that a fundamental mode adiabatically launched into a multimode SOI waveguide with submicron grating offers well-defined flat-top bandpass filter characteristics in transmission. The transmitted spectral bandwidth is controlled by adjusting both waveguide and grating design parameters. The bandwidth is further narrowed down by cascading two gratings with detuned parameters. A semi-analytical model is used to analyze the filter characteristics (1500  nm≤λ≤1650  nm) of the device operating in transverse-electric polarization. The proposed devices were fabricated with an optimized set of design parameters in a SOI substrate with a device layer thickness of 250 nm. The pass bandwidth of waveguide devices integrated with single-stage gratings are measured to be ∼24  nm, whereas the device with two cascaded gratings with slightly detuned periods (ΔΛ=2  nm) exhibits a pass bandwidth down to ∼10  nm.

Generation of an elliptic hollow beam using Mathieu and Bessel functions.

Science.gov (United States)

Chakraborty, Rijuparna; Ghosh, Ajay

2006-09-01

A new (to our knowledge) technique for the generation of a propagation-invariant elliptic hollow beam is reported. It avoids the use of the radial Mathieu function and hence is mathematically simpler. Bessel functions with their arguments having elliptic locus are used to generate the mask, which is then recorded using holographic technique. To generate such an elliptic beam, both the angular Mathieu function, i.e., elliptic vortex term, and the expression for the circular vortex are used separately. The resultant mask is illuminated with a plane beam, and the proper filtering of its Fourier transform generates the expected elliptic beam. Results with both vortex terms are satisfactory. It has been observed that even for higher ellipticity the vortices do not separate.

GLUT4 expression at the plasma membrane is related to fibre volume in human skeletal muscle fibres

DEFF Research Database (Denmark)

Gaster, M; Vach, W; Beck-Nielsen, H

2002-01-01

In this study we examined the relationship between GLUT4 expression at the plasma membrane and muscle fibre size in fibre-typed human muscle fibres by immunocytochemistry and morphometry in order to gain further insight into the regulation of GLUT4 expression. At the site of the plasma membrane...

The Riddle of the Apparently Hollow Himalaya

Indian Academy of Sciences (India)

The Riddle of the Apparently Hollow Himalaya. Ramesh .... It was as if the Himalayas were hollow inside. ... block would be consistent with the ground elevation in such a ... Alternative models and possible preference: Many refinements of.

X-ray diffraction of modified and graft polymerised cellulose fibres

International Nuclear Information System (INIS)

Ouajai, S.; Hodzic, A.; Shanks, R.A.

2003-01-01

Full text: The aim of this research is to modify natural cellulosic fibres in order to improve and increase consistency of their performance in biodegradable materials. Fibre modification consisted of solvent extraction and NaOH treatment in order to remove wax and lignin before grafting with acrylonitrile monomer. The mechanical properties, moisture regain and pore structures were investigated. Finally an analysis of crystalline structure was performed using quantitative FTIR, WAXD and SAXS to assess the relationship between structure and properties after modification. Materials: Hemp (Cannabis sativa), Australian Hemp Resource and Manufacture (AHRM) and Flax (Durafibre Grade 1, 95 % purity), Cargill, Canada. Pretreatments: Dewaxing by acetone extraction, alkalisation with NaOH solutions, grafting reaction with acrylonitrile and AIBN thermal initiator after absorption of the monomer. Surface and pore structure analysis using Micromeritics ASAP 2000 BET adsorption instrument, FTIR Perkin-Elmer 2000 spectrometer, wide angle X-ray diffraction, Bruker AXS D8, Ni-filtered CuKα radiation (λ 0.1542 nm) at 40 kV and 35 mA. The diffractograms were recorded from 5 to 60 deg of 2 θ (Bragg angle) by a goniometer with a scintillation counter, scanning speed 0.02 deg/s and sampling rate of 2 data/s. The 2-D small-angle X-ray data was collected by Bruker AXS, Nanostar from 0.5 to 14 deg of 2θ (Bragg angle). Typical exposure time was 5 hours at 40 kV and 35 mA. Single fibre mechanical properties were carried out on a Rheometric DMTA IV at 0.03 mm/min. Moisture regain measurements were performed gravimetrically. The crystalline structure of the fibres were changed from cellulose I to cellulose II after NaOH treatment. The intensity of the 1431 cm -1 band was reduced while the 898 cm -1 band was increased and shifted to 893 cm -1 with an increase of NaOH concentration. X-ray diffractograms of flax and hemp were obtained for each treatment. Untreated fibre shows the

Integral blow moulding for cycle time reduction of CFR-TP aluminium contour joint processing

Science.gov (United States)

Barfuss, Daniel; Würfel, Veit; Grützner, Raik; Gude, Maik; Müller, Roland

2018-05-01

Integral blow moulding (IBM) as a joining technology of carbon fibre reinforced thermoplastic (CFR-TP) hollow profiles with metallic load introduction elements enables significant cycle time reduction by shortening of the process chain. As the composite part is joined to the metallic part during its consolidation process subsequent joining steps are omitted. In combination with a multi-scale structured load introduction element its form closure function enables to pass very high loads and is capable to achieve high degrees of material utilization. This paper first shows the process set-up utilizing thermoplastic tape braided preforms and two-staged press and internal hydro formed load introduction elements. Second focuses on heating technologies and process optimization. Aiming at cycle time reduction convection and induction heating in regard to the resulting product quality is inspected by photo micrographs and computer tomographic scans. Concluding remarks give final recommendations for the process design in regard to the structural design.

Compaction in optical fibres and fibre Bragg gratings under nuclear reactor high neutron and gamma fluence

Energy Technology Data Exchange (ETDEWEB)

Remy, L.; Cheymol, G. [CEA, French Nuclear Energy Commission, Nuclear Energy Division, DPC/SEARS/LISL Bat 467 CEA Saclay 91191 Gif/Yvette Cedex (France); Gusarov, A. [SCK.CEN - Belgian Nuclear Research center, Boeretang 200 2400 Mol (Belgium); Morana, A.; Marin, E.; Girard, S. [Universite de Saint-Etienne, Laboratoire Hubert Curien, UMR CNRS5516, 18, rue du Pr. Lauras, F-42000 Saint-Etienne (France)

2015-07-01

In the framework of the development by CEA and SCK.CEN of a Fabry Perot Sensor (FPS) able to measure dimensional changes in Material Testing Reactor (MTR), the first goal of the SAKE 1 (Smirnof extention - Additional Key-tests on Elongation of glass fibres) irradiation was to measure the linear compaction of single mode fibres under high fast neutron fluence. Indeed, the compaction of the fibre which forms one side of the Fabry Perot cavity, may in particular cause a noticeable measurement error. An accurate quantification of this effect is then required to predict the radiation-induced drift and optimize the sensor design. To achieve this, an innovative approach was used. Approximately seventy uncoated fibre tips (length: 30 to 50 mm) have been prepared from several different fibre samples and were installed in the SCK.CEN BR2 reactor (Mol Belgium). After 22 days of irradiation a total fast (E > 1 MeV) fluence of 3 to 5x10{sup 19} n{sub fast}/cm{sup 2}, depending on the sample location, was accumulated. The temperature during irradiation was 291 deg. C, which is not far from the condition of the intended FPS use. A precise measurement of each fibre tip length was made before the irradiation and compared to the post irradiation measurement highlighting a decrease of the fibres' length corresponding to about 0.25% of linear compaction. The amplitude of the changes is independent of the capsule, which could mean that the compaction effect saturates even at the lowest considered fluence. In the prospect of performing distributed temperature measurement in MTR, several fibre Bragg gratings written using a femtosecond laser have been also irradiated. All the gratings were written in radiation hardened fibres, and underwent an additional treatment with a procedure enhancing their resistance to ionizing radiations. A special mounting made it possible to test the reflection and the transmission of the gratings on fibre samples cut down to 30 to 50 mm. The comparison

Stochastic simulation and robust design optimization of integrated photonic filters

Directory of Open Access Journals (Sweden)

Weng Tsui-Wei

2016-07-01

Full Text Available Manufacturing variations are becoming an unavoidable issue in modern fabrication processes; therefore, it is crucial to be able to include stochastic uncertainties in the design phase. In this paper, integrated photonic coupled ring resonator filters are considered as an example of significant interest. The sparsity structure in photonic circuits is exploited to construct a sparse combined generalized polynomial chaos model, which is then used to analyze related statistics and perform robust design optimization. Simulation results show that the optimized circuits are more robust to fabrication process variations and achieve a reduction of 11%–35% in the mean square errors of the 3 dB bandwidth compared to unoptimized nominal designs.

Hollow metal nanostructures for enhanced plasmonics (Conference Presentation)

Science.gov (United States)

Genç, Aziz; Patarroyo, Javier; Sancho-Parramon, Jordi; Duchamp, Martial; Gonzalez, Edgar; Bastus, Neus G.; Houben, Lothar; Dunin-Borkowski, Rafal; Puntes, Victor F.; Arbiol, Jordi

2016-03-01

Complex metal nanoparticles offer a great playground for plasmonic nanoengineering, where it is possible to cover plasmon resonances from ultraviolet to near infrared by modifying the morphologies from solid nanocubes to nanoframes, multiwalled hollow nanoboxes or even nanotubes with hybrid (alternating solid and hollow) structures. We experimentally show that structural modifications, i.e. void size and final morphology, are the dominant determinants for the final plasmonic properties, while compositional variations allow us to get a fine tuning. EELS mappings of localized surface plasmon resonances (LSPRs) reveal an enhanced plasmon field inside the voids of hollow AuAg nanostructures along with a more homogeneous distributions of the plasmon fields around the nanostructures. With the present methodology and the appropriate samples we are able to compare the effects of hybridization at the nanoscale in hollow nanostructures. Boundary element method (BEM) simulations also reveal the effects of structural nanoengineering on plasmonic properties of hollow metal nanostructures. Possibility of tuning the LSPR properties of hollow metal nanostructures in a wide range of energy by modifying the void size/shell thickness is shown by BEM simulations, which reveals that void size is the dominant factor for tuning the LSPRs. As a proof of concept for enhanced plasmonic properties, we show effective label free sensing of bovine serum albumin (BSA) with some of our hollow nanostructures. In addition, the different plasmonic modes observed have also been studied and mapped in 3D.

Ni hollow spheres as catalysts for methanol and ethanol electrooxidation

Energy Technology Data Exchange (ETDEWEB)

Xu, Changwei [Department of Chemistry and Institute of Nanochemistry, Jinan University, Guangzhou 510632 (China); School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Hu, Yonghong; Rong, Jianhua; Liu, Yingliang [Department of Chemistry and Institute of Nanochemistry, Jinan University, Guangzhou 510632 (China); Jiang, San Ping [School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798 (Singapore)

2007-08-15

In this paper, we successfully synthesized Ni hollow spheres consisting of needle-like nickel particles by using silica spheres as template with gold nanoparticles seeding method. The Ni hollow spheres are applied to methanol and ethanol electrooxidation in alkaline media. The results show that the Ni hollow spheres give a very high activity for alcohol electrooxidation at a very low nickel loading of 0.10 mg cm{sup -2}. The current on Ni hollow spheres is much higher than that on Ni particles. The onset potential and peak potential on Ni hollow spheres are more negative than that on Ni particles for methanol and ethanol electrooxidation. The Ni hollow spheres may be of great potential in alcohol sensor and direct alcohol fuel cells. (author)

Active control of long-period fiber-grating-based filters made in erbium-doped optical fibers

Czech Academy of Sciences Publication Activity Database