Use of coir pith particles in composites with Portland cement.

Science.gov (United States)

Brasileiro, Gisela Azevedo Menezes; Vieira, Jhonatas Augusto Rocha; Barreto, Ledjane Silva

2013-12-15

Brazil is the fourth largest world's producer of coconut (Cocos nucifera L.). Coconut crops generate several wastes, including, coir pith. Coir pith and short fibers are the byproducts of extracting the long fibers and account for approximately 70% of the mature coconut husk. The main use of coir pith is as an agricultural substrate. Due to its shape and small size (0.075-1.2 mm), this material can be considered as a particulate material. The aim of this study was to evaluate the use of coir pith as an aggregate in cementitious composites and to evaluate the effect of the presence of sand in the performance of these composites. Some composites were produced exclusively with coir pith particles and other composites with coir pith partially substituting the natural sand. The cementitious composites developed were tested for their physical and mechanical properties and characterized by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy to evaluate the effect of coir pith particles addition in cement paste and sand-cement-mortar. The statistical significance of the results was evaluated by one-way analysis of variance (ANOVA) test followed by multiple comparisons of the means by Tukey's test that showed that the composites with coir pith particles, with or without natural sand, had similar mechanical results, i.e., means were not statistically different at 5% significance level. There was a reduction in bulk density and an improved post-cracking behavior in the composites with coir pith particles compared to conventional mortar and to cement paste. These composites can be used for the production of lightweight, nonstructural building materials, according to the values of compressive strength (3.97-4.35 MPa) and low bulk density (0.99-1.26 g/cm(3)). Copyright © 2013 Elsevier Ltd. All rights reserved.

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.

Determination of material properties for short fibre reinforced C/C-SiC

Directory of Open Access Journals (Sweden)

Hausherr J.-M.

2015-01-01

Full Text Available Determining the mechanical properties of short fibre reinforced CMC using standard sized coupons has always been a challenge due to a high statistical scattering of the measured values. Although the random orientation of short fibres results in a quasi-isotropic material behavior of 2D-structures with a sufficiently large volume, the small volume typical for test coupons usually results in a non-isotropic fibre orientation in the tested volume. This paper describes a method for manufacturing unidirectional oriented short fibre reinforced CMC materials and presents material properties of UD-C/C-SiC. After verifying the fibre orientation of the CMC using micro-computed tomography, coupons were extracted to determine the orthotropic material properties. These orthotropic material properties were then used to predict the properties of C/C-SiC with randomly distributed short fibres. To validate the method, micro-computed tomography is used to quantitatively determine the fibre orientation within coupons extracted from randomly distributed short fibre C/C-SiC. After mechanical three-point-bending tests, the measured stiffness and bending strength is compared with the predicted properties. Finally, the data are used to devise a method suited for reducing the inherent large spread of material properties associated with the measurement of CMC materials with randomly distributed short fibres.

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.

Coir dust reinforced recycled polypropylene composites

International Nuclear Information System (INIS)

Santos, Bianca B. dos; Costa, Marysilvia F. da; Thire, Rossana M. da S.M.

2015-01-01

The environmental impacts caused by disposed plastics encourage the search for new alternatives. Recycling polymers leads to the degradation of their mechanical properties, which can be modified by the addition of fillers. In this paper, recycled polypropylene from plastic cups with 2%, 5% and 10% of coir dust were produced with and without the addition of additives. These composites were characterized by tensile tests, X-ray diffraction, differential scanning calorimetry and scanning electron microscopy on the fracture surface. It was verified the effectiveness of the addition of coir dust in improving the elasticity modulus of recycled polypropylene besides the effectiveness of additives used in promoting the adhesion of the powder to the matrix. However, higher levels of coir dust caused the appearance of air bubbles inside the material, which contributed to its embrittlement. The addition of coir dust promoted a decrease in the degree of polypropylene crystallinity. (author)

Toughness enhancement of tungsten reinforced with short tungsten fibres

Energy Technology Data Exchange (ETDEWEB)

Jiang, Y. [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China); Zhang, L.H. [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China); University of Science and Technology of China, Hefei 230026 (China); Fang, Q.F., E-mail: qffang@issp.ac.cn [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China); University of Science and Technology of China, Hefei 230026 (China); Zhang, T.; Wang, X.P.; Hao, T.; Liu, C.S. [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China)

2017-04-06

The feasibility and toughening efficiency of the short tungsten fibre reinforcement on tungsten were investigated in W{sub f}/W composites fabricated by powder metallurgy method of spark plasma sintering. Fibres in the composites presented a Z-free laminar structure. Partial recrystallization of fibre grains occurred but fibre crack or damage was not detected. Fracture energy of W{sub f}/W composites was estimated in tensile tests, and the results indicated great toughness improvement over pure tungsten in virtue of frictional pullout and plastic deformation of fibres, and matrix-fibres interfacial debonding since 873 K. The specimen with mass fraction of 10% and fibre diameter of 100 µm exhibits the largest elongation of 9±1.1% and the highest ultimate strength of 482±13 MPa at 873 K.

Chemical Modification Effect on the Mechanical Properties of Coir Fiber

Directory of Open Access Journals (Sweden)

Samia Sultana Mir

2012-04-01

Full Text Available Natural fiber has a vital role as a reinforcing agent due to its renewable, low cost, biodegradable, less abrasive and eco-friendly nature. Whereas synthetic fibers like glass, boron, carbon, metallic, ceramic and inorganic fibers are expensive and not eco-friendly. Coir is one of the natural fibers easily available in Bangladesh and cheap. It is derived from the husk of the coconut (Cocos nucifera. Coir has one of the highest concentrations of lignin, which makes it stronger. In recent years, wide range of research has been carried out on fiber reinforced polymer composites [4-13].The aim of the present research is to characterize brown single coir fiber for manufacturing polymer composites reinforced with characterized fibers. Adhesion between the fiber and polymer is one of factors affecting the strength of manufactured composites. In order to increase the adhesion, the coir fiber was chemically treated separately in single stage (with Cr₂(SO₄3•12(H₂O and double stages (with CrSO₄ and NaHCO₃. Both the raw and treated fibers were characterized by tensile testing, Fourier transform infrared (FTIR spectroscopic analysis, scanning electron microscopic analysis. The result showed that the Young’s modulus increased, while tensile strength and strain to failure decreased with increase in span length. Tensile properties of chemically treated coir fiber was found higher than raw coir fiber, while the double stage treated coir fiber had better mechanical properties compared to the single stage treated coir fiber. Scanning electron micrographs showed rougher surface in case of the raw coir fiber. The surface was found clean and smooth in case of the treated coir fiber. Thus the performance of coir fiber composites in industrial application can be improved by chemical treatment.

Gamma irradiation stability studies of coir pith - a lignocellulosic biosorbent for strontium

International Nuclear Information System (INIS)

Parab, Harshala; Remya Devi, P.S.; Shenoy, Niyoti; Kumar, Sangita D.; Reddy, A.V.R.

2015-01-01

The effects of gamma irradiation on a lignocellulosic biosorbent-coir pith was investigated. The biosorbent was irradiated up to a dosage of 3.6 MGy using high intensity 60 Co source. The physicochemical changes in the coir pith after exposure to γ radiation were evaluated using FTIR and TG-DTA measurements. Coir pith, when irradiated in air showed structural similarity with that of non irradiated coir. However irradiation in aqueous medium partially altered the chemical linkages in coir pith. Thermal analysis revealed stepwise decomposition of structural constituents of coir pith. The changes in the strontium sorption properties of the coir pith upon γ-irradiation were examined. (author)

Microbial degradation of coconut coir dust for biomass production

Energy Technology Data Exchange (ETDEWEB)

Uyenco, F.R.; Ochoa, J.A.K.

Several species of white-rot fungi were studied for its ability to degrade the lignocellulose components of coir dust at optimum conditions. The most effective fungi was Phanerochaeta chrysosporium UPCC 4003. This organism degraded the lignocellulose complex of coir dust at a rate of about 25 percent in 4 weeks. The degradation process was carried on with minimal nitrogen concentration, coconut water supplementation and moisture levels between 85-90 percent. Shake flask cultures of the degraded coir dust using cellulolytic fungi were not effective. In fermentor cultures with Chaetomium cellulolyticum UPCC 3934, supplemented coir dust was converted into a microbial biomass product (MBP) with 15.58 percent lignin, 19.20 percent cellulose and 18.87 percent protein. More work is being done on the utilization of coir dust on a low technology.

Extraction and characterization of coconut (Cocos nucifera L. coir dust

Directory of Open Access Journals (Sweden)

A. U. Israel1,

2011-12-01

Full Text Available Studies were carried out on the characterization and extraction of coconut coir dust using water, acetone, acetone/water (70/30, (50/50 respectively. The acetone extract of the coir dust was phytochemically screened for tannins, polyphenols,flavanoids, phlobatannins. The moisture, ash, lignin, and cellulose contents of the coir dust were determined bymeasuring the cation exchange capacity (CEC and the pH were found to be 2.39 mmol g-1 and 6.4 respectively. The degree ofswelling of coir dust increased with increased solvent contact time. The percentage extract showed the best solvent systemto be acetone/water (70/30. In all the solvent systems, the smaller the particle size of coir dust, the greater the amount ofextract. The phytochemical screening of the acetone extract indicated significant amount of tannins, flavanoids and otherpolyphenols in coir dust.

Treated Coconut Coir Pith as Component of Cementitious Materials

Directory of Open Access Journals (Sweden)

Dana Koňáková

2015-01-01

Full Text Available The presented paper deals with utilization of raw and treated coir pith as potential component of cementitious composites. The studied material is coir pith originating from a coconut production. Its applicability as cement mixture component was assessed in terms of the physical properties of concrete containing different amount of coir pith. Basic physical properties, compressive and bending strength, and hygric transport characteristics as well as thermal properties belong among the studied characteristics. It was proved that the concrete with 5% (by mass of cement of this waste material shows appropriate physical properties and it gives rise to an applicable material for building structures. Generally, the coir pith can be regarded as lightening additive. When 10% of coir pith was added, it has led to higher deterioration of properties than what is acceptable since such dosing is greatly increasing the total porosity. The influence of chemical treatment of coir pith was evaluated as well; both tested treatment methods improved the performance of cementitious composites while the acetylation was somewhat more effective the treatment by NaOH.

Effect of phenolic compounds released during degradation of Coir ...

African Journals Online (AJOL)

MICHAEL

www.bioline.org.br/ja. Effect of phenolic compounds released during degradation of Coir pith by ... of the culture filtrate appears to be non toxic in the tested animals @ JASEM. Coir pith is a highly ... degradation of coir pith by fungi and bacteria were already reported, ... no.1 filter paper and used as feed for the experimental ...

Strength behaviour of kerosene coated coir fiber-reinforced expansive soil

OpenAIRE

Ramasubbarao Godavarthi Venkata

2014-01-01

Coir fibers are extracted from the husks surrounding the coconut. Coir fibers can be effectively used as reinforcing material but it has less durability and hence coir fiber coated with kerosene is used as reinforcement in the present study. The objective of the present investigation is to study the strength behavior of expansive soil reinforced with 5mm long randomly distributed kerosene coated coir fibers in 0% (unreinforced), 0.5%, 1% and 1.5% by dry wei...

Batch biomethanation of banana trash and coir path

Energy Technology Data Exchange (ETDEWEB)

Deivanai, K.; Bai, R.K. [Madurai Kamaraj Univ. (India)

1995-08-01

Anaerobic digestion of banana trash and coir pith was carried out for a period of one month by batch digestion. During biomethanation reduction of total- and volatile-solids was, respectively, 25.3 and 39.6% in banana trash and 13.6 and 21.6% in coir pith. A production of 9.22 l and 1.69 l (per kg TS added) of biogas with average methane content of 72 and 80% was achieved from banana trash and coir pith, respectively. (author)

Expansive soil stabilization with coir waste and lime for flexible pavement subgrade

Science.gov (United States)

Narendra Goud, G.; Hyma, A.; Shiva Chandra, V.; Sandhya Rani, R.

2018-03-01

Expansive soil properties can be improved by various methods to make it suitable for construction of flexible pavement. The coir pith is the by-product (bio-waste) generated from coir industry during extraction of coir fiber from coconut husk. Openly disposed coir pith can make the surrounding areas unhygienic. This bio-waste can be one of the potential materials to stabilize the expansive soils. In the present study coir pith and lime are used as stabilizers. Different combinations of coir pith contents (1%, 2% and 3%) and lime contents (2%, 3% and 4%)are used to study the behavior of expansive soil. Unconfined compressive strength (UCS) of unstabilized and stabilized soils was determined. Optimum content of coir pith and lime are determined based on UCS of the soil. California bearing ratio of soil determined at optimum contents of coir pith and lime. Flexible pavement layer compositions for two levels of traffic using stabilized soil subgrade.

Treated Coconut Coir Pith as Component of Cementitious Materials

OpenAIRE

Koňáková, Dana; Vejmelková, Eva; Čáchová, Monika; Siddique, Jamal Akhter; Polozhiy, Kirill; Reiterman, Pavel; Keppert, Martin; Černý, Robert

2015-01-01

The presented paper deals with utilization of raw and treated coir pith as potential component of cementitious composites. The studied material is coir pith originating from a coconut production. Its applicability as cement mixture component was assessed in terms of the physical properties of concrete containing different amount of coir pith. Basic physical properties, compressive and bending strength, and hygric transport characteristics as well as thermal properties belong among the studied...

Nasobronchial allergy and pulmonary function abnormalities among coir workers of Alappuzha.

Science.gov (United States)

Panicker, Venugopal; Karunakaran, Raseela; Ravindran, C

2010-07-01

Coir is a commercially important natural fiber obtained from the coconut husk. Coir can be woven into strong twine or rope, and is used for padding mattresses, upholstery, etc. Coir industry provides a major share of occupation to the natives of Alappuzha district of Kerala State. It has been noticed earlier that there is increased incidence of nasobronchial allergy among the population involved in this industry. This study was aimed at recognizing the symptomatology and pulmonary functional impairment among symptomatic coir workers. All coir workers who attended our institute over a period of three years were included in the study. Detailed occupational history was taken; symptom profile was studied in detail, clinical examination and pulmonary function tests conducted. Among the 624 symptomatic coir workers selected for this purpose, 64 patients had purely nasal symptoms, while 560 had symptoms of nasobronchial allergy. 357 patients had reversible obstruction on PFT, while 121 had only small airway obstruction. We conclude that coir work induced nasobronchial allergy and pulmonary function abnormalities. In absence of CT scan and bronchial challenge testing it may be inappropriate to label coir work as occupational hazard. However the present study may be used as thought provoking study to initiate further understanding.

Mechanical property evaluation of natural fiber coir composite

International Nuclear Information System (INIS)

Harish, S.; Michael, D. Peter; Bensely, A.; Lal, D. Mohan; Rajadurai, A.

2009-01-01

The fiber which serves as a reinforcement in reinforced plastics may be synthetic or natural. Past studies show that only artificial fibers such as glass, carbon etc., have been used in fiber-reinforced plastics. Although glass and other synthetic fiber-reinforced plastics possess high specific strength, their fields of application are very limited because of their inherent higher cost of production. In this connection, an investigation has been carried out to make use of coir, a natural fiber abundantly available in India. Natural fibers are not only strong and lightweight but also relatively very cheap. In the present work, coir composites are developed and their mechanical properties are evaluated. Scanning electron micrographs obtained from fractured surfaces were used for a qualitative evaluation of the interfacial properties of coir/epoxy and compared with glass fiber/epoxy. These results indicate that coir can be used as a potential reinforcing material for making low load bearing thermoplastic composites

Mechanical properties of short random oil palm fibre reinforced epoxy composites

International Nuclear Information System (INIS)

Mohd Zuhri Mohamed Yusoff; Mohd Sapuan Salit; Napsiah Ismail; Riza Wirawan

2010-01-01

This paper presents the study of mechanical properties of short random oil palm fibre reinforced epoxy (OPF/epoxy) composites. Empty fruit bunch (EFB) was selected as the fibre and epoxy as the matrix. Composite plate with four different volume fractions of oil palm fibre was fabricated, (5 vol %, 10 vol %, 15 vol % and 20 vol %). The fabrication was made by hand-lay up techniques. The tensile and flexural properties showed a decreasing trend as the fibre loading was increased. The highest tensile properties was obtained for the composite with fibre loading of 5 vol % and there were no significant effect for addition of more than 5 vol % to the flexural properties. Interaction between fibre and matrix was observed from the scanning electron microscope (SEM) micrograph. (author)

Enzymatic Hydrolysis of Alkaline Pretreated Coconut Coir

Directory of Open Access Journals (Sweden)

Akbarningrum Fatmawati

2013-06-01

Full Text Available The purpose of this research is to study the effect of concentration and temperature on the cellulose and lignin content, and the reducing sugars produced in the enzymatic hydrolysis of coconut coir. In this research, the coconut coir is pretreated using 3%, 7%, and 11% NaOH solution at 60oC, 80oC, and 100oC. The pretreated coir were assayed by measuring the amount of cellulose and lignin and then hydrolysed using Celluclast and Novozyme 188 under various temperature (30oC, 40oC, 50oC and pH (3, 4, 5. The hydrolysis results were assayed for the reducing sugar content. The results showed that the alkaline delignification was effective to reduce lignin and to increase the cellulose content of the coir. The best delignification condition was observed at 11% NaOH solution and 100oC which removed 14,53% of lignin and increased the cellulose content up to 50,23%. The best condition of the enzymatic hydrolysis was obtained at 50oC and pH 4 which produced 7,57 gr/L reducing sugar. © 2013 BCREC UNDIP. All rights reservedReceived: 2nd October 2012; Revised: 31st January 2013; Accepted: 6th February 2013[How to Cite: Fatmawati, A., Agustriyanto, R., Liasari, Y. (2013. Enzymatic Hydrolysis of Alkaline Pre-treated Coconut Coir. Bulletin of Chemical Reaction Engineering & Catalysis, 8 (1: 34-39 (doi:10.9767/bcrec.8.1.4048.34-39[Permalink/DOI: http://dx.doi.org/10.9767/bcrec.8.1.4048.34-39] | View in  |

Cr(VI) adsorption from electroplating plating wastewater by chemically modified coir pith.

Science.gov (United States)

Suksabye, Parinda; Thiravetyan, Paitip

2012-07-15

Coir pith samples were chemically modified by grafting with acrylic acid for the removal of Cr(VI) from electroplating wastewater. The presence of acrylic acid on the coir pith surface was verified by a scanning electron microscope with an electron dispersive x-ray spectrometer (SEM/EDX), Fourier transform infrared spectroscopy (FTIR) and thermogravimetry (TG). The carbonyl groups (C==O) from the carboxylic acids (COOH) increased on the coir pith surface after grafting with acrylic acid. In addition, the thermal stability of the acrylic acid-grafted coir pith also improved. The optimum conditions for grafting the acrylic acid on the coir pith consisted of 2 M acrylic acid and 0.00125 M ceric ammonium nitrate (CAN, as an initiator). The maximum Cr(VI) removal (99.99 ± 0.07%) was obtained with the following conditions: a 1.3% (w/v) dosage of acrylic acid-grafted coir pith, a system pH of 2, a contact time of 22 h, a temperature of 30 °C, a particle size of <150 μm and an initial Cr(VI) of 1,171 mg l(-1). At system pH of 2, Cr(VI) in the HCrO(4)(-) form can be adsorbed with acrylic acid-grafted coir pith via an electrostatic attraction. The adsorption isotherm of 2 M acrylic acid-grafted coir pith exhibited a good fit with the Langmuir isotherm. The maximum Cr(VI) adsorption capacity of the 2 M acrylic acid-grafted coir pith was 196.00 mg Cr(VI) g(-1) adsorbent, whereas for coir pith without grafting, the maximum Cr(VI) removal was 165.00 mg Cr(VI) g(-1) adsorbent. The adsorption capacity of the acrylic acid-grafted coir pith for Cr(VI) was higher compared to the original coir pith. This result was due to the enhancement of the carbonyl groups on the coir pith surface that may have involved the mechanism of chromium adsorption. The X-ray absorption near edged structure (XANES) and desorption studies suggested that most of the Cr(III) that presented on the acrylic acid-grafted coir pith was due to the Cr(VI) being reduced to Cr(III) on the adsorbent surface. FTIR

Utilization of waste coconut coir dust as a source of fuel

Energy Technology Data Exchange (ETDEWEB)

Festin, T.F.; Jose, W.I.

1979-01-01

A review on the production of a gaseous fuel by the pyrolysis of waste coir dust, which is a by-product in the manufacturing of coir fibers from coconut husks. Experimental and pilot-plant studies on the pyrolysis of coir dust are discussed and the properties of the dust and the fuel gas produced are given. (Refs. 13).

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

Validity and Reproducibility of a Habitual Dietary Fibre Intake Short Food Frequency Questionnaire.

Science.gov (United States)

Healey, Genelle; Brough, Louise; Murphy, Rinki; Hedderley, Duncan; Butts, Chrissie; Coad, Jane

2016-09-10

Low dietary fibre intake has been associated with poorer health outcomes, therefore having the ability to be able to quickly assess an individual's dietary fibre intake would prove useful in clinical practice and for research purposes. Current dietary assessment methods such as food records and food frequency questionnaires are time-consuming and burdensome, and there are presently no published short dietary fibre intake questionnaires that can quantify an individual's total habitual dietary fibre intake and classify individuals as low, moderate or high habitual dietary fibre consumers. Therefore, we aimed to develop and validate a habitual dietary fibre intake short food frequency questionnaire (DFI-FFQ) which can quickly and accurately classify individuals based on their habitual dietary fibre intake. In this study the DFI-FFQ was validated against the Monash University comprehensive nutrition assessment questionnaire (CNAQ). Fifty-two healthy, normal weight male (n = 17) and female (n = 35) participants, aged between 21 and 61 years, completed the DFI-FFQ twice and the CNAQ once. All eligible participants completed the study, however the data from 46% of the participants were excluded from analysis secondary to misreporting. The DFI-FFQ cannot accurately quantify total habitual dietary fibre intakes, however, it is a quick, valid and reproducible tool in classifying individuals based on their habitual dietary fibre intakes.

Short and long carbon fibre reinforced Cu-matrix composites: microstructural results and structural origin of properties

International Nuclear Information System (INIS)

Buchgraber, W.

1997-01-01

Carbon fibre reinforced copper matrix composites possess properties of copper, i.e. excellent thermal and electrical conductivities, and properties of carbon fibre, i.e. a small thermal expansion coefficient. Since the desirable properties of the composite can be obtained by selecting the amount, type and orientation of the carbon fibres, it is considered to be suitable for use as electric and electronic materials. This lecture focuses on two-dimensional isotropic carbon fibre reinforced copper matrix composites with long or short carbon fibres. Short carbon fibre reinforced copper matrix composites have been produced by hot-pressing of copper coated short carbon fibres. During hot-pressing, the carbon fibres take on a preferred orientation in a plane perpendicular to the hot pressing direction. Within this plane the fibre orientation is random. Long carbon fibre reinforced copper matrix composites have been made by hot pressing of monolayers consisting of copper coated long carbon fibres. Different orientations of the monolayers will be compared. Both the physical and mechanical properties of the discussed composites are strongly influenced not only by the properties of its individual constituents, but also by the microstructure and properties of the fibre matrix interface. The problem of poor wettability of the carbon fibre by the copper matrix will be discussed. The microstructure of several types of carbon fibre reinforced copper matrix composites will be discussed. Their thermophysical properties will be compared with microstructural results. (author)

Breakage and debonding of short brittle fibres among particulates in a metal matrix

DEFF Research Database (Denmark)

Tvergaard, Viggo

2004-01-01

or fracture of a relatively long discontinuous fibre among particulates that do not fail. A cohesive zone model that accounts for normal separation as well as tangential separation is used to represent debonding, while fibre fracture is represented by a critical value of the average tensile stress on a cross......The competition of failure by fibre cracking or decohesion of the fibre-matrix interface is analysed for aluminium reinforced by aligned, short SiC fibres. An axisymmetric unit-cell model containing a number of differently shaped fibres or particulates is used here to represent failure by debonding...

Median and common peroneal neuropathy in coir workers of Alappuzha district, Kerala.

Science.gov (United States)

Chandra, Sadanandavalli Retnaswami; Anand, Biji; Issac, Thomas Gregor

2017-01-01

Coir work, in a large number of people involves mechanically rolling the coconut fibers into coir which is later subjected to various processes. The primary work is done as a cottage industry specially by women in the sitting posture for several hours. This study reports evidence of median and common peroneal neuropathy electrophysiologically in people who had been engaged in this job for several years. This study was initiated to establish the possible relationship between coir work and symptomatic neuropathies which was seen in that region with all investigations " for other causes not " contributing to the etiological diagnosis. One hundred and forty-two upper limbs and 142 lower limbs in patients engaged in long years of coir work but having no symptoms were evaluated electrophysiologically with informed consent and financial compensation, appropriate inclusion and exclusion criteria were followed as described in the text. There is electrophysiological evidence for median and common peroneal neuropathy in persons engaged in long years of coir work. Coir workers neuropathy appears to be a new occupational neuropathy which can be prevented by following simple preventive measures.

Kinetic study of enzymatic hydrolysis of acid-pretreated coconut coir

Science.gov (United States)

Fatmawati, Akbarningrum; Agustriyanto, Rudy

2015-12-01

Biomass waste utilization for biofuel production such as bioethanol, has become more prominent currently. Coconut coir is one of lignocellulosic food wastes, which is abundant in Indonesia. Bioethanol production from such materials consists of more than one step. Pretreatment and enzymatic hydrolysis is crucial steps to produce sugar which can then be fermented into bioethanol. In this research, ground coconut coir was pretreated using dilute sulfuric acid at 121°C. This pretreatment had increased the cellulose content and decreased the lignin content of coconut coir. The pretreated coconut coir was hydrolyzed using a mix of two commercial cellulase enzymes at pH of 4.8 and temperature of 50°C. The enzymatic hydrolysis was conducted at several initial coconut coir slurry concentrations (0.1-2 g/100 mL) and reaction times (2-72 hours). The reducing sugar concentration profiles had been produced and can be used to obtain reaction rates. The highest reducing sugar concentration obtained was 1,152.567 mg/L, which was produced at initial slurry concentration of 2 g/100 mL and 72 hours reaction time. In this paper, the reducing sugar concentrations were empirically modeled as a function of reaction time using power equations. Michaelis-Menten kinetic model for enzymatic hydrolysis reaction is adopted. The kinetic parameters of that model for sulfuric acid-pretreated coconut coir enzymatic hydrolysis had been obtained which are Vm of 3.587×104 mg/L.h, and KM of 130.6 mg/L.

The Use of Arbuscular Mycorrhizal Fungi to Improve Strawberry Production in Coir Substrate

Directory of Open Access Journals (Sweden)

Louisa Robinson Boyer

2016-08-01

Full Text Available Strawberry is an important fruit crop within the UK. To reduce the impact of soil-borne diseases and extend the production season, more than half of the UK strawberry production is now in substrate (predominantly coir under protection. Substrates such as coir are usually depleted of microbes including arbuscular mycorrhizal fungi (AMF and consequently the introduction of beneficial microbes is likely to benefit commercial cropping systems. Inoculating strawberry plants in substrate other than coir has been shown to increase plants tolerance to soil-borne pathogens and water stress. We carried out studies to investigate whether AMF could improve strawberry production in coir under low nitrogen input and regulated deficit irrigation. Application of AMF led to an appreciable increase in the size and number of class I fruit, especially under either deficient irrigation or low nitrogen input condition. However, root length colonisation by AMF was reduced in strawberry grown in coir compared to soil and Terragreen. Furthermore, the appearance of AMF colonising strawberry and maize roots grown in coir showed some physical differences from the structure in colonised roots in soil and Terragreen: the colonization structure appeared to be more compact and smaller in coir.

Biosoftening of coir fiber using selected microorganisms.

Science.gov (United States)

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

2005-12-01

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

Ballistic Impact Response of Woven Hybrid Coir/Kevlar Laminated Composites

Directory of Open Access Journals (Sweden)

Azrin Hani A.R

2016-01-01

Full Text Available The effects of different laminated hybrid composites stacking configuration subjected to ballistic impact were investigated. The hybrid composites consist of woven coir (C and woven Kevlar (K layers laminated together. The samples of woven coir were prepared using handloom device. The composites were produced by stacking the laminated woven coir and Kevlar alternately with the presence of the binder. The samples were tested under ballistic impact with different stacking configuration. The results obtained had successfully achieved the National Institute of Justice (NIJ standard level IIA with energy absorption of 435.6 kJ and 412.2 kJ under the projectile speed of between 330 m/s and 321 m/s respectively. Samples that having Kevlar layer at the front face and woven coir layer as back face achieved partial penetration during projectile impact. This orientation is proven to have good impact energy absorption and able to stop projectile at the second panel of the composites.

Growth of lowland broccoli coconut coir dust and peat based growing media using fertigation system

Energy Technology Data Exchange (ETDEWEB)

Ahmad, Asiah; Abdul Rahman, Shyful Azizi; Nordin, Latiffah; Abdullah, Hazlina; Ruslan, Abdul Razak [Malaysian Inst. for Nuclear Technology Research MINT, Bangi (Malaysia). Agrotechnology and Bioscineces Div.; Taib, Mohd Idris [Malaysian Inst. for Nuclear Technology Research MINT, Bangi (Malaysia). Intelligent Group

2004-07-01

A study was carried out inside the greenhouse to determine the response of lowland broccoli (Brassica oleracea) plants grown in five mixtures of coconut coir dust and peat as the growing media. The growing mixes were prepared in the following ratios (% by vol): 100% coconut coir dust, 75% coconut coir dust + 25% peat, 50% coconut coir dust + 50% peat, 25% coconut coir dust + 75% peat and 100% peat. The plants were supplied with 200 mg 1-1 nitrogen using a computerized fertigation system developed at MINT Plants grown on 100% peat exhibited reduced plant growth and yield compared to plants grown on mixes containing coconut coir dust. Plants growth and yield were increased on growing media contained > 50% coconut coir dust; however, the highest total plant dry weight, plant height and yield were obtained from plants grown on 100% coconut coir dust. Total nitrogen concentration in the leaves and stems was not significantly different in all mixture of the growing media regardless of whether coconut coir dust or peat was used. In general, nitrate -nitrogen concentrations were lowest in the floret than in the leaves and stem tissues of plants grown on all growing media used in the study. However, nitrate-nitrogen concentrations in the leaves, stems and florets were lowest in the plants grown on 100% peat compared to the plants grown on growing media containing coconut coir dust. The concentrations of nitrate-nitrogen in the florets, which ranged from 290 to 450 mg N kg-l/dry weight, are considered to be under permissible levels by European standards. (Author)

Growth of lowland broccoli coconut coir dust and peat based growing media using fertigation system

International Nuclear Information System (INIS)

Asiah Ahmad; Shyful Azizi Abdul Rahman; Latiffah Nordin; Hazlina Abdullah; Abdul Razak Ruslan; Mohd Idris Taib

2004-01-01

A study was carried out inside the greenhouse to determine the response of lowland broccoli (Brassica oleracea) plants grown in five mixtures of coconut coir dust and peat as the growing media. The growing mixes were prepared in the following ratios (% by vol): 100% coconut coir dust, 75% coconut coir dust + 25% peat, 50% coconut coir dust + 50% peat, 25% coconut coir dust + 75% peat and 100% peat. The plants were supplied with 200 mg 1-1 nitrogen using a computerized fertigation system developed at MINT Plants grown on 100% peat exhibited reduced plant growth and yield compared to plants grown on mixes containing coconut coir dust. Plants growth and yield were increased on growing media contained > 50% coconut coir dust; however, the highest total plant dry weight, plant height and yield were obtained from plants grown on 100% coconut coir dust. Total nitrogen concentration in the leaves and stems was not significantly different in all mixture of the growing media regardless of whether coconut coir dust or peat was used. In general, nitrate -nitrogen concentrations were lowest in the floret than in the leaves and stem tissues of plants grown on all growing media used in the study. However, nitrate-nitrogen concentrations in the leaves, stems and florets were lowest in the plants grown on 100% peat compared to the plants grown on growing media containing coconut coir dust. The concentrations of nitrate-nitrogen in the florets, which ranged from 290 to 450 mg N kg-l/dry weight, are considered to be under permissible levels by European standards. (Author)

Rigid Polyurethane Foam Reinforced Coconut Coir Fiber Properties

OpenAIRE

Mohd Azham Azmi

2012-01-01

This research work studied the properties of composite foam panels. Coconut coir fibers were used as reinforcement in polyurethane (PU) foam in order to increase the properties of foam. This composite foam panels were fabricated by using polyurethane molded method. The polyurethane foam panels reinforced from 5 to 20wt% coconut coir were produced to investigate the physical and mechanical test via density test and three point bending test respectively. It was found that the density test resul...

Wear rate and surface coating optimization of coconut coir-based ...

Indian Academy of Sciences (India)

The use of fuzzy logic for modeling surface parameters of coconut coir-based composite is the focus of this research paper. Natural fiber–polymer composite has been developed by combining coconut coir as a stimulator and polyester as a fixative. This sturdy material is resistant to scratches in the coating process on the ...

Drying kinetics and mathematical modeling of hot air drying of coconut coir pith.

Science.gov (United States)

Fernando, J A K M; Amarasinghe, A D U S

2016-01-01

Drying kinetics of coir pith was studied and the properties of compressed coir pith discs were analyzed. Coir pith particles were oven dried in the range of temperatures from 100 to 240 °C and the rehydration ability of compressed coir pith was evaluated by finding the volume expansion. The optimum drying temperature was found to be 140 °C. Hot air drying was carried out to examine the drying kinetics by allowing the coir pith particles to fluidize and circulate inside the drying chamber. Particle motion within the drying chamber closely resembled the particle motion in a flash dryer. The effective moisture diffusivity was found to increase from 1.18 × 10(-8) to 1.37 × 10(-8) m(2)/s with the increase of air velocity from 1.4 to 2.5 m/s respectively. Correlation analysis and residual plots were used to determine the adequacy of existing mathematical models for describing the drying behavior of coir pith. The empirical models, Wang and Singh model and Linear model, were found to be adequate for accurate prediction of drying behavior of coir pith. A new model was proposed by modifying the Wang and Singh model and considering the effect of air velocity. It gave the best correlation between observed and predicted moisture ratio with high value of coefficient of determination (R(2)) and lower values of root mean square error, reduced Chi square (χ(2)) and mean relative deviation (E%).

Natural fibres actuators for smart bio-inspired hygromorph biocomposites

Science.gov (United States)

Le Duigou, Antoine; Requile, Samuel; Beaugrand, Johnny; Scarpa, Fabrizio; Castro, Mickael

2017-12-01

Hygromorph biocomposite (HBC) actuators make use of the transport properties of plant fibres to generate an out-of-plane displacement when a moisture gradient is present. HBC actuators possess a design based on the bilayer configuration of natural hygromorph actuators (like pine cone, wheat awn, Selaginella lepidophyll). In this work we present a series of design guidelines for HBCs with improved performance, low environmental footprints and high durability in severe environments. We develop a theoretical actuating response (curvature) formulation of maleic anhydride polypropylene (MAPP)/plant fibres based on bimetallic actuators theory. The actuation response is evaluated as a function of the fibre type (flax, jute, kenaf and coir). We demonstrate that the actuation is directly related to the fibre microstructure and its biochemical composition. The jute and flax fibres appear to be the best candidates for use in HBCs. Flax/MAPP and jute/MAPP HBCs exhibit similar actuating behaviours during the sorption phase (amplitude and speed), but different desorption characteristics due to the combined effect of the lumen size, fibre division and biochemical composition on the desorption mechanism. During hygromechanical fatigue tests the jute/MAPP HBCs exhibit a drastic improvement in durability compared to their flax counterparts. We also provide a demonstration on how HBCs can be used to trigger deployment of more complex structures based on Origami and Kirigami designs.

Effects of ageing on single muscle fibre contractile function following short-term immobilisation

DEFF Research Database (Denmark)

Hvid, Lars G; Ortenblad, Niels; Aagaard, Per

2011-01-01

Very little attention has been given to the combined effects of healthy ageing and short-term disuse on the contractile function of human single muscle fibres. Therefore, the present study investigated the effects of 2 weeks of lower limb cast immobilisation (i.e. disuse) on selected contractile...... IIa: young 18% and old 25%; P selective decrease in Ca(2+) sensitivity in MHC IIa fibres of young (P ....05), respectively. In conclusion, 2 weeks of lower limb immobilisation caused greater impairments in single muscle fibre force and specific force in MHC IIa than MHC I fibres independently of age. In contrast, immobilisation-induced changes in Ca(2+) sensitivity that were dependent on age and MHC isoform....

Creep behaviour of a short-fibre C/PPS composite

Czech Academy of Sciences Publication Activity Database

Fíla, T.; Koudelka_ml., Petr; Kytýř, Daniel; Hos, J.; Šleichrt, J.

2016-01-01

Roč. 50, č. 3 (2016), s. 413-417 ISSN 1580-2949 R&D Projects: GA TA ČR(CZ) TA03010209 Institutional support: RVO:68378297 Keywords : creep * short fibre composite * C/PPS * Findley’s model * DIC Subject RIV: JI - Composite Materials Impact factor: 0.436, year: 2016 http://mit.imt.si/Revija/izvodi/mit163/fila.pdf

Evaluation of secondary crystallization effect in poly hydroxybutyrate and silanized coir dust composites

International Nuclear Information System (INIS)

Mello, Carolina C. de; Costa, Marysilvia F. da; Thire, Rossana M.S.M.

2011-01-01

Polyhydroxybutyrate is a natural and biodegradable polyester, susceptible to secondary crystallization when it is stored at environment temperature. Coir dust is an agroindustrial waste which has good prospects for use as filler in composites. In this context, PHB-coir dust composites were produced. The compatibilization was made by coir dust silanization. The secondary crystallization evolution on materials was evaluated by x-ray diffraction. Its effect was verified by tension tests which presented that elastic modulus increases when crystallinity increases. (author)

Structural characterization of lignin isolated from coconut (Cocos nucifera) coir fibers.

Science.gov (United States)

Rencoret, Jorge; Ralph, John; Marques, Gisela; Gutiérrez, Ana; Martínez, Ángel T; del Río, José C

2013-03-13

The structure of the isolated milled "wood" lignin from coconut coir has been characterized using different analytical methods, including Py-GC/MS, 2D NMR, DFRC, and thioacidolysis. The analyses demonstrated that it is a p-hydroxyphenyl-guaiacyl-syringyl (H-G-S) lignin, with a predominance of G units (S/G ratio 0.23) and considerable amounts of associated p-hydroxybenzoates. Two-dimensional NMR indicated that the main substructures present in this lignin include β-O-4' alkyl aryl ethers followed by phenylcoumarans and resinols. Two-dimensional NMR spectra also indicated that coir lignin is partially acylated at the γ-carbon of the side chain with p-hydroxybenzoates and acetates. DFRC analysis showed that acetates preferentially acylate the γ-OH in S rather than in G units. Despite coir lignin's being highly enriched in G-units, thioacidolysis indicated that β-β' resinol structures are mostly derived from sinapyl alcohol. Finally, we find evidence that the flavone tricin is incorporated into the coconut coir lignin, as has been recently noted for various grasses.

The study of mechanical properties of pineapple leaf fibre reinforced tapioca based bioplastic resin composite

Directory of Open Access Journals (Sweden)

Mathivanan D.

2016-01-01

Full Text Available Natural fibre reinforced composite has brought the material engineering to a high new level of research. Natural fibres are compatible with matrices like polypropylene and can be used as reinforcement material to reduce the composition of plastic in a material. Natural fibres such as kenaf, pineapple leaf, and coir already found its importance in reducing the dependence of petroleum based products. However the biodegradability of the product at the end of the intended lifespan is still questionable. This has led many researches to look for a suitable replacement for synthetic fibres and achieve better adhesion between fibre and matrix. In this study, fiber and matrix which are hydrophilic in nature was used and the mixture was extruded and hot compressed to acquire better mechanical properties. The specimens were fabricated and tested according to ASTM D638. The 30% composition illustrates the best average modulus value among other composition and from this result it can be concluded that the increase of PALF fibre in TBR composite increases the modulus strength of the composite.

Development of Briquette from Coir Dust and Rice Husk Blend: An Alternative Energy Source

Directory of Open Access Journals (Sweden)

Md. Hamidul Islam

2014-05-01

Full Text Available Biomass is one of the predominant renewable energy sources and the use of biomass for the energy generation has got much attention due to its environmental friendliness. Densification of coir dust into fuel briquette can solve waste disposal problem as well as can serve as an alternative energy source. The objective of this study was to investigate the possibility of producing briquette from coir dust and rice husk blend without binder. During this study, a briquetting experiment was conducted with different coir dust and rice husk blends (i.e. coir dust and rice husk ratio of 80:20, 60:40, 50:50, 40:60, 20:80 and 0:100. Briquetting operation was performed using a die-screw press type briquetting machine. The briquettes were tested to evaluate their density, compressive strength, calorific value, burning rate and water vaporizing capacity and it was found that mixing ratio had a significant effect on the physical, mechanical and combustion properties of the coir dust-rice husk briquettes. Density, compressive strength and calorific value and water vaporizing capacity were increased with increasing mixing ratio while burning rate was decreased. Coir dust-rice husk briquettes with mixing ratio of 20:80 had higher density (1.413 g/cm3, compressive strength (218.4 N/cm2, calorific value (4879 kcal/kg, water vaporizing capacity (0.853 l/kg and low burning rate (0.783 kg/hour followed by the mixing ratio 40:60, 50:50, 60:40 and 0:100. The results indicate that coir dust and rice husk blend briquettes were found to have better overall handling characteristics over rice husk briquette. However, production of briquettes from coir dust and rice husk at mixing ratio of 50:50 was found to be more suitable for commercial application in terms of cost effectiveness.

Median and common peroneal neuropathy in coir workers of Alappuzha district, Kerala

Directory of Open Access Journals (Sweden)

Sadanandavalli Retnaswami Chandra

2017-01-01

for other causes not” contributing to the etiological diagnosis. Subjects and Methods: One hundred and forty-two upper limbs and 142 lower limbs in patients engaged in long years of coir work but having no symptoms were evaluated electrophysiologically with informed consent and financial compensation, appropriate inclusion and exclusion criteria were followed as described in the text. Results: There is electrophysiological evidence for median and common peroneal neuropathy in persons engaged in long years of coir work. Conclusions: Coir workers neuropathy appears to be a new occupational neuropathy which can be prevented by following simple preventive measures.

Surface Heave Behaviour of Coir Geotextile Reinforced Sand Beds

Science.gov (United States)

Lal, Dharmesh; Sankar, N.; Chandrakaran, S.

2017-06-01

Soil reinforcement by natural fibers is one of the cheapest and attractive ground improvement techniques. Coir is the most abundant natural fiber available in India and due to its high lignin content; it has a larger life span than other natural fibers. It is widely used in India for erosion control purposes, but its use as a reinforcement material is rather limited. This study focuses on the use of coir geotextile as a reinforcement material to reduce surface heave phenomena occurring in shallow foundations. This paper presents the results of laboratory model tests carried out on square footings supported on coir geotextile reinforced sand beds. The influence of various parameters such as depth of reinforcement, length, and number of layers of reinforcement was studied. It was observed that surface heave is considerably reduced with the provision of geotextile. Heave reduction up to 98.7% can be obtained by the proposed method. Heave reduction is quantified by a non-dimensional parameter called heave reduction factor.

Enhancement of Short Chain Fatty Acid Production from Millet Fibres ...

African Journals Online (AJOL)

Pharmacotherapy Group, Faculty of Pharmacy, University of Benin, Benin City, 300001 Nigeria. ... Methods: The effect of millet dietary fibre fermentation on production of short chain fatty ... fildes PYF enrichment solution was used as the .... where Pa is the peak area of SCFA, Ps is the ..... enzymatic- gravimetric method.

Numerical Investigation of Thermal and Thermo-mechanical Effective Properties for Short Fibre Reinforced Composite

Science.gov (United States)

Ioannou, Ioannis; Hodzic, Alma; Gitman, Inna M.

2017-10-01

This study aims to investigate the thermal conductivity and the linear coefficient of thermal expansion for short fibre reinforced composites. The study combines numerical and statistical analyses in order to primarily examine the representative size and the effective properties of the volume element. Effects of various micromechanical parameters, such as fibre's aspect ratio and fibre's orientation, on the minimum representative size are discussed. The numerically acquired effective properties, obtained for the representative size, are presented and compared with analytical models.

Process for production of high density/high performance binderless boards from whole coconut husk : part I : Lignin as intrinsic thermosetting binder resin

NARCIS (Netherlands)

Dam, van J.E.G.; Oever, van den M.J.A.; Teunissen, W.; Keijsers, E.R.P.; Peralta, A.G.

2004-01-01

Coconuts are abundantly growing in coastal areas of tropical countries. The coconut husk is available in large quantities as residue from coconut production in many areas, which is yielding the coarse coir fibre. The husk comprises ca. 30 wt.% coir fibres and 70 wt.% pith. Both fibre and pith are

Immobilization of anaerobic bacteria on rubberized-coir for psychrophilic digestion of night soil.

Science.gov (United States)

Dhaked, Ram Kumar; Ramana, Karna Venkat; Tomar, Arvind; Waghmare, Chandrakant; Kamboj, Dev Vrat; Singh, Lokendra

2005-08-01

Low-ambient temperatures, biodigesters due to low-growth rate of the constituent bacterial consortium. Immobilization of anaerobic bacteria has been attempted in the biodigester operating at 10 degrees C. Various matrices were screened and evaluated for the immobilization of bacteria in digesters. Anaerobic digestion of night soil was carried out with hydraulic retention time in the range of 9-18 days. Among the tested matrices, rubberized-coir was found to be the most useful at 10 degrees C with optimum hydraulic retention time of 15 days. Optimum amount of coir was found as 25 g/L of the working volume of biodigesters. Immobilization of bacteria on the coir was observed by scanning electron microscopy and fluorescent microscopy. The study indicates that rubberized-coir can be utilized to increase biodegradation of night soil at higher organic loading. Another advantage of using this matrix is that it is renewable and easily available in comparison to other synthetic polymeric matrices.

Load transfer in short fibre reinforced metal matrix composites

International Nuclear Information System (INIS)

Garces, Gerardo; Bruno, Giovanni; Wanner, Alexander

2007-01-01

The internal load transfer and the deformation behaviour of aluminium-matrix composites reinforced with 2D-random alumina (Saffil) short fibres was studied for different loading modes. The evolution of stress in the metallic matrix was measured by neutron diffraction during in situ uniaxial deformation tests. Tensile and compressive tests were performed with loading axis parallel or perpendicular to the 2D-reinforcement plane. The fibre stresses were computed based on force equilibrium considerations. The results are discussed in light of a model recently established by the co-authors for composites with visco-plastic matrix behaviour and extended to the case of plastic deformation in the present study. Based on that model, the evolution of internal stresses and the macroscopic stress-strain were simulated. Comparison between the experimental and computational results shows a qualitative agreement in all relevant aspects

Column study of chromium(VI) adsorption from electroplating industry by coconut coir pith.

Science.gov (United States)

Suksabye, Parinda; Thiravetyan, Paitip; Nakbanpote, Woranan

2008-12-15

The removal of Cr(VI) from electroplating wastewater by coir pith was investigated in a fixed-bed column. The experiments were conducted to study the effect of important parameters such as bed depth (40-60cm) and flow rate (10-30ml min(-1)). At 0.05 C(t)/C(0), the breakthrough volume increased as flow rate decreased or a bed depth increased due to an increase in empty bed contact time (EBCT). The bed depth service time model (BDST) fit well with the experimental data in the initial region of the breakthrough curve, while the simulation of the whole curve using non-linear regression analysis was effective using the Thomas model. The adsorption capacity estimated from the BDST model was reduced with increasing flow rate, which was 16.40mg cm(-3) or 137.91mg Cr(VI)g(-1) coir pith for the flow rates of 10ml min(-1) and 14.05mg cm(-3) or 118.20mg Cr(VI)g(-1) coir pith for the flow rates of 30ml min(-1). At the highest bed depth (60cm) and the lowest flow rate (10mlmin(-1)), the maximum adsorption reached 201.47mg Cr(VI)g(-1) adsorbent according to the Thomas model. The column was regenerated by eluting chromium using 2M HNO(3) after adsorption studies. The desorption of Cr(III) in each of three cycles was about 67-70%. The desorption of Cr(III) in each cycle did not reach 100% due to the fact that Cr(V) was present through the reduction of Cr(VI), and was still in coir pith, possibly bound to glucose in the cellulose part of coir pith. Therefore, the Cr(V) complex cannot be desorbed in solution. The evidence of Cr(V) signal was observed in coir pith, alpha-cellulose and holocellulose extracted from coir pith using electron spin resonance (ESR).

Column study of chromium(VI) adsorption from electroplating industry by coconut coir pith

Energy Technology Data Exchange (ETDEWEB)

Suksabye, Parinda [Joint Graduate School of Energy and Environment, King Mongkut' s University of Technology Thonburi, 91 Pracha-Utit Road, Bangmod, Thungkru, Bangkok 10140 (Thailand); Thiravetyan, Paitip [Division of Biotechnology, School of Bioresources and Technology, King Mongkut' s University of Technology Thonburi, 83 Moo.8 Thakham, Bangkhuntien, Bangkok 10150 (Thailand)], E-mail: paitip.thi@kmutt.ac.th; Nakbanpote, Woranan [Pilot Plant Development and Training Institute, King Mongkut' s University of Technology Thonburi, 83 Moo.8 Thakham, Bangkhuntien, Bangkok 10150 (Thailand)

2008-12-15

The removal of Cr(VI) from electroplating wastewater by coir pith was investigated in a fixed-bed column. The experiments were conducted to study the effect of important parameters such as bed depth (40-60 cm) and flow rate (10-30 ml min{sup -1}). At 0.05 C{sub t}/C{sub 0}, the breakthrough volume increased as flow rate decreased or a bed depth increased due to an increase in empty bed contact time (EBCT). The bed depth service time model (BDST) fit well with the experimental data in the initial region of the breakthrough curve, while the simulation of the whole curve using non-linear regression analysis was effective using the Thomas model. The adsorption capacity estimated from the BDST model was reduced with increasing flow rate, which was 16.40 mg cm{sup -3} or 137.91 mg Cr(VI) g{sup -1} coir pith for the flow rates of 10 ml min{sup -1} and 14.05 mg cm{sup -3} or 118.20 mg Cr(VI) g{sup -1} coir pith for the flow rates of 30 ml min{sup -1}. At the highest bed depth (60 cm) and the lowest flow rate (10 ml min{sup -1}), the maximum adsorption reached 201.47 mg Cr(VI) g{sup -1} adsorbent according to the Thomas model. The column was regenerated by eluting chromium using 2 M HNO{sub 3} after adsorption studies. The desorption of Cr(III) in each of three cycles was about 67-70%. The desorption of Cr(III) in each cycle did not reach 100% due to the fact that Cr(V) was present through the reduction of Cr(VI), and was still in coir pith, possibly bound to glucose in the cellulose part of coir pith. Therefore, the Cr(V) complex cannot be desorbed in solution. The evidence of Cr(V) signal was observed in coir pith, {alpha}-cellulose and holocellulose extracted from coir pith using electron spin resonance (ESR)

Column study of chromium(VI) adsorption from electroplating industry by coconut coir pith

International Nuclear Information System (INIS)

Suksabye, Parinda; Thiravetyan, Paitip; Nakbanpote, Woranan

2008-01-01

The removal of Cr(VI) from electroplating wastewater by coir pith was investigated in a fixed-bed column. The experiments were conducted to study the effect of important parameters such as bed depth (40-60 cm) and flow rate (10-30 ml min -1 ). At 0.05 C t /C 0 , the breakthrough volume increased as flow rate decreased or a bed depth increased due to an increase in empty bed contact time (EBCT). The bed depth service time model (BDST) fit well with the experimental data in the initial region of the breakthrough curve, while the simulation of the whole curve using non-linear regression analysis was effective using the Thomas model. The adsorption capacity estimated from the BDST model was reduced with increasing flow rate, which was 16.40 mg cm -3 or 137.91 mg Cr(VI) g -1 coir pith for the flow rates of 10 ml min -1 and 14.05 mg cm -3 or 118.20 mg Cr(VI) g -1 coir pith for the flow rates of 30 ml min -1 . At the highest bed depth (60 cm) and the lowest flow rate (10 ml min -1 ), the maximum adsorption reached 201.47 mg Cr(VI) g -1 adsorbent according to the Thomas model. The column was regenerated by eluting chromium using 2 M HNO 3 after adsorption studies. The desorption of Cr(III) in each of three cycles was about 67-70%. The desorption of Cr(III) in each cycle did not reach 100% due to the fact that Cr(V) was present through the reduction of Cr(VI), and was still in coir pith, possibly bound to glucose in the cellulose part of coir pith. Therefore, the Cr(V) complex cannot be desorbed in solution. The evidence of Cr(V) signal was observed in coir pith, α-cellulose and holocellulose extracted from coir pith using electron spin resonance (ESR)

Mechanical and dielectric characterization of hemp fibre reinforced polypropylene (HFRPP by dry impregnation process

Directory of Open Access Journals (Sweden)

2010-03-01

Full Text Available Natural fibres such as jute, coir, sisal, bamboo and pineapple are known to have high specific strength and can be effectively used in composites in various applications. The use of hemp fibres to reinforce the polymer aroused great interest and expectations amongst scientists and materials engineers. In this paper, composites with isotactic polypropylene (iPP matrix and hemp fibres were studied. These materials were manufactured via the patented FIBROLINE process based on the principle of the dry impregnation of a fibre assembly with a thermoplastic powder (iPP, using an alternating electric field. The aim of this paper is to show the influence of fibre/matrix interfaces on dielectric properties coupled with mechanical behaviours. Fibres or more probably the fibre/matrix interfaces allow the diffusion of electric charges and delocalise the polarisation energy. In this way, damages are limited during mechanical loading and the mechanical properties of the composites increase. The structure of composite samples was investigated by X-ray and FTIR analysis. The mechanical properties were analysed by quasistatic and dynamic tests. The dielectric investigations were carried out using the SEMME (Scanning Electron Microscope Mirror Effect method coupled with the measurement of the induced current (ICM.

Precast self-compacting concrete (PSCC) panel with added coir fiber: An overview

Science.gov (United States)

Afif Iman, Muhamad; Mohamad, Noridah; Samad, Abdul Aziz Abdul; Goh, W. I.; Othuman Mydin, M. A.; Afiq Tambichik, Muhamad; Bosro, Mohamad Zulhairi Mohd; Wirdawati, A.; Jamaluddin, N.

2018-04-01

Self-compacting concrete (SCC) is the alternative way to reduce construction time and improve the quality and strength of concrete. The panel system fabricated from SCC contribute to the IBS system that is sustainable and environmental friendly. The precast self-compacting concrete (PSCC) panel with added coir fiber will be overview in this paper. The properties of SCC and coir fiber are studied and reviewed from the previous researches. Finite element analysis is used to support the experimental results by conduction parametric simulation study on PSCC under flexure load. In general, it was found that coir fiber has a significant influence on the flexural load and crack propagation. Higher fiber incorporated in SCC resulted with higher ultimate load of PSCC.

Coir dust reinforced recycled polypropylene composites; Compositos de polipropileno reciclado e po de coco

Energy Technology Data Exchange (ETDEWEB)

Santos, Bianca B. dos; Costa, Marysilvia F. da; Thire, Rossana M. da S.M., E-mail: bianca@metalmat.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil)

2015-07-01

The environmental impacts caused by disposed plastics encourage the search for new alternatives. Recycling polymers leads to the degradation of their mechanical properties, which can be modified by the addition of fillers. In this paper, recycled polypropylene from plastic cups with 2%, 5% and 10% of coir dust were produced with and without the addition of additives. These composites were characterized by tensile tests, X-ray diffraction, differential scanning calorimetry and scanning electron microscopy on the fracture surface. It was verified the effectiveness of the addition of coir dust in improving the elasticity modulus of recycled polypropylene besides the effectiveness of additives used in promoting the adhesion of the powder to the matrix. However, higher levels of coir dust caused the appearance of air bubbles inside the material, which contributed to its embrittlement. The addition of coir dust promoted a decrease in the degree of polypropylene crystallinity. (author)

Removal of radium from aqueous solutions using adsorbent produced from coconut coir pith

International Nuclear Information System (INIS)

Zalina Laili; Muhamat Omar; Mohd Zaidi Ibrahim; Esther Phillip; Mohd Abdul Wahab Yusof; Hassan, A.

2008-08-01

A study was conducted to evaluate the potential use of the coconut coir pith as an adsorbent for the removal of radium from aqueous solutions. Experiments to establish adsorptions as a function of pH and contact time were carried out. The results showed that radium adsorption are dependent upon pH and contact time of coconut coir pith with aqueous solutions. 70-80% of radium were adsorbed in the neutral to alkaline pH range. The amount of radium adsorbed also increased with contact time, reaching an optimum after 250 min. Thus, it can be concluded that the coconut coir pith has the potential to be used as an adsorbent in radium removal from aqueous solutions. (Author)

ABSORÇÃO DE NUTRIENTES EM MUDAS DE BERINJELA CULTIVADAS EM PÓ DE COCO VERDE

Directory of Open Access Journals (Sweden)

Alexandre Bosco Oliveira

2009-01-01

Full Text Available This study aimed to carry through chemical caracterization of the coconut fiber powder and evaluate its effect on the absorption of nutrients in the as medium substrate on the production of eggplant seedling. The experiment was conducted for forty days under greenhouse, and it was used seeds of the Florida Market cultivar were cultivated in polyetilene strays with 54 cells and irrigated with nutritive solution two times for day. The substrates were used dust and fiber green coconut coir fibre, in the proportions of 100% of dust, 75% of dust + 25% of fiber and 50% of dust + 50% of fiber, washed and not washed; dry coconut coir fibre not washed; rind of green coconut grinded (fiber and dust mix from machine washed end not washed (fiber and dust mix from machine; commercial substrate not fertilized and control (green coconut coir fibre not washed and not fertilized. It was used a statistical randomized block design with eleven treatments and four replications, with 25 plants per replications. The chemical characterization of substrates was carried through and was valuated nutrient total contents of the plant upper parts. The best results were observed for the seedlings grown in dry coconut coir fibre not washed, followed by commercial substrate and green coconut coir fibre washed.

Remediation of cadmium contaminated vertisol mediated by Prosopis charcoal and coir pith

OpenAIRE

Palaninaicker Senthilkumar; Duraisamy Prabha; Subpiramaniyan Sivakumar; Chandra Venkatasamy Subbhuraam

2015-01-01

Metal contamination of soil due to industrial and agricultural activities is increasingly becoming a global problem, thereby affecting animal and human life, thus rendering soil unsuitable for agricultural purposes. Remediation of cadmium (Cd) contaminated soil (Vertisol) using agricultural by products as source of organic amendments, Coir pith- a by-product of the coir industry and Prosopis charcoal- prepared by burning Prosopis plant wood (Prosopis juliflora L.) was investigated. The allevi...

Environmental friendly method for the extraction of coir fibre and isolation of nanofibre

CSIR Research Space (South Africa)

Abraham, E

2013-02-01

Full Text Available 560, Kerala, India d Fibres and Textiles Competence Area, CSIR, Materials Science and Manufacturing, PE, South Africa ?Corresponding author: Tel.: +91 479 2301730. E-mail address: lapothan@gmail.com (L.A. Pothen). ABSTRACT The objective...

Properties of polyurethane foam/coconut coir fiber as a core material and as a sandwich composites component

Science.gov (United States)

Azmi, M. A.; Abdullah, H. Z.; Idris, M. I.

2013-12-01

This research focuses on the fabrication and characterization of sandwich composite panels using glass fiber composite skin and polyurethane foam reinforced coconut coir fiber core. The main objectives are to characterize the physical and mechanical properties and to elucidate the effect of coconut coir fibers in polyurethane foam cores and sandwich composite panels. Coconut coir fibers were used as reinforcement in polyurethane foams in which later were applied as the core in sandwich composites ranged from 5 wt% to 20 wt%. The physical and mechanical properties found to be significant at 5 wt% coconut coir fiber in polyurethane foam cores as well as in sandwich composites. It was found that composites properties serve better in sandwich composites construction.

Properties of polyurethane foam/coconut coir fiber as a core material and as a sandwich composites component

International Nuclear Information System (INIS)

Azmi, M A; Abdullah, H Z; Idris, M I

2013-01-01

This research focuses on the fabrication and characterization of sandwich composite panels using glass fiber composite skin and polyurethane foam reinforced coconut coir fiber core. The main objectives are to characterize the physical and mechanical properties and to elucidate the effect of coconut coir fibers in polyurethane foam cores and sandwich composite panels. Coconut coir fibers were used as reinforcement in polyurethane foams in which later were applied as the core in sandwich composites ranged from 5 wt% to 20 wt%. The physical and mechanical properties found to be significant at 5 wt% coconut coir fiber in polyurethane foam cores as well as in sandwich composites. It was found that composites properties serve better in sandwich composites construction

Application of bridging-law concepts to short-fibre composites

DEFF Research Database (Denmark)

Lindhagen, J.E.; Gamstedt, Kristofer; Berglund, L.A.

2000-01-01

This is the third paper in a series of four where notch sensitivity, fracture energy and bridging laws are studied in short-fibre polymer composites. Here, bridging laws are derived from experimental crack-opening profiles in centre-hole notched tensile specimens. The materials studied are three...... types of commercial glass-mat composites with different reinforcement structures and matrices. The materials have softening bridging laws and the calculated fracture energies from bridging laws are in good agreement with values determined directly by experiment. The calculated maximum local bridging...

Isolation and Rheological Characterization of Cellulose Nanofibrils (CNFs from Coir Fibers in Comparison to Wood and Cotton

Directory of Open Access Journals (Sweden)

Daran Yue

2018-03-01

Full Text Available In this report, the isolation and rheological characterization of cellulose nanofibrils from coir (CNFs-1 were studied and compared with the CNFs from wood (CNFs-2 and cotton (CNFs-3. Cellulose nanofibrils were isolated successfully from coir fibers by chemical treatments followed by ultrasonic fibrillation. During ultrasonic processing, the size and the crystal structure of the CNFs were influenced by the raw materials. In comparison to CNFs-2 and CNFs-3, CNFs-1 from coir fibers presented diverse advantages, such as sufficient fibrillation with a low diameter distribution, in the range of 2–4 nm and high crystallinity. In the dynamic rheology study of CNFs-1, elastic behavior was observed and maintained due to the formation of gel-like steady network structures, which could not be easily deconstructured by frequency shearing and temperature changing. All results indicated that coir fibers could be used as a valuable resource for the preparation of CNFs, which exhibited comparable properties with those isolated from wood, in regard to morphology and rheological properties. This work provides a basis for further advanced applications using the CNFs isolated from coir fibers.

Effects of ageing on single muscle fibre contractile function following short-term immobilisation

DEFF Research Database (Denmark)

Hvid, Lars G; Ørtenblad, Niels; Aagaard, Per

2011-01-01

Very little attention has been given to the combined effect of healthy ageing and short-term disuse on the contractile function of human single muscle fibres. Therefore, the present study investigated the effects of 2 weeks of lower limb cast immobilisation (i.e. disuse) on selected contractile...

Analysis of Micro-Morphology, Thermal Conductivity, Thermal Diffusivity and Specific Heat Capacity of Coconut Fibre Reinforced Foamed Concrete

Directory of Open Access Journals (Sweden)

Othuman Mydin M.A.

2014-01-01

Full Text Available With the quest for green construction and affordable housing systems for both rural and urban populations in Malaysia, various proposals focusing on cutting down on conventional building material costs have been put forward. One vanguard suggestion has been the sourcing, development and use of alternative, non-conventional local construction materials including the prospect of using some agricultural wastes as construction materials. This research describes experimental studies on the use of coconut coir fibre as an enhancer of foamed concrete with a focus on 2 parameters which are morphology properties and thermal properties of different percentages of coconut fibre (0%, 0.2% and 0.4%. In this study the addition of coconut fibre significantly improved all the properties investigated. The results of the tests showed that the thermal properties of foamed concrete improved with an increase in the proportion of coconut fibre. Findings from this research will also be used to address the knowledge gap on the subject of foamed concrete and will provide an improved understanding and raised awareness of the potential for using waste materials for domestic construction.

Development of a New Class of Scintillating Fibres with Very Short Decay Time and High Light Yield

International Nuclear Information System (INIS)

Borshchev, O.; Ponomarenko, S.; Surin, N.; Cavalcante, A.B.R.; Gavardi, L.; Gruber, L.; Joram, C.; Shinji, O.

2017-01-01

We present first studies of a new class of scintillating fibres which are characterised by very short decay times and high light yield. The fibres are based on a novel type of luminophores admixed to a polystyrene core matrix. These so-called Nanostructured Organosilicon Luminophores (NOL) have high photoluminescense quantum yield and decay times just above 1 ns. A blue and a green emitting prototype fibre with 250 μm diameter were produced and characterised in terms of attenuation length, ionisation light yield, decay time and tolerance to x-ray irradiation. The well-established Kuraray SCSF-78 and SCSF-3HF fibres were taken as references. Even though the two prototype fibres mark just an intermediate step in an ongoing development, their performance is already on a competitive level. In particular, their decay time constants are about a factor of two shorter than the fastest known fibres, which makes them promising candidates for time critical applications.

Power generation using coir-pith and wood derived producer gas in diesel engines

Energy Technology Data Exchange (ETDEWEB)

Ramadhas, A.S.; Jayaraj, S.; Muraleedharan, C. [Department of Mechanical Engineering, National Institute of Technology Calicut, Calicut-673 601, Kerala State (India)

2006-10-15

Partial combustion of biomass in the gasifier generates producer gas that can be used for heating purposes and as supplementary or sole fuel in internal combustion engines. In this study, the potential of coir-pith and wood chips as the feedstock for gasifier is analyzed. The performance of the gasifier-engine system is analyzed by running the engine for various producer gas-air flow ratios and at different load conditions. The system is experimentally optimized with respect to maximum diesel savings and lower emissions in the dual fuel mode operation while using coir-pith and wood chips separately. The performance and emission characteristics of the dual fuel engine are compared with that of diesel engine at different load conditions. Specific energy consumption in the dual fuel mode of operation is found to be in the higher side at all load conditions. The brake thermal efficiency of the engine while using wood chips in the dual mode operation is higher than that of coir-pith. The CO emission is higher in the case of dual fuel mode of operation as compared to that of diesel mode. In the dual fuel mode of operation, the higher diesel savings is achieved while using wood chips as compared to that of coir-pith. The comparison of the performance and emission characteristics of the dual fuel engine with diesel engine is also described. (author)

Remediation of cadmium contaminated vertisol mediated by Prosopis charcoal and coir pith

Directory of Open Access Journals (Sweden)

Palaninaicker Senthilkumar

2015-01-01

Full Text Available Metal contamination of soil due to industrial and agricultural activities is increasingly becoming a global problem, thereby affecting animal and human life, thus rendering soil unsuitable for agricultural purposes. Remediation of cadmium (Cd contaminated soil (Vertisol using agricultural by products as source of organic amendments, Coir pith- a by-product of the coir industry and Prosopis charcoal- prepared by burning Prosopis plant wood (Prosopis juliflora L. was investigated. The alleviation potential of Prosopis charcoal and Coir pith on the negative effects of Cd in soil was evaluated in pot culture experiments with Vigna radiata as the test plant, a Cd accumulator. Cadmium addition to soil resulted in accumulation of Cd in all plant parts of V. radiata predominantly in roots. The influence of Cd in the presence and absence of organic amendments on the various biological and chemical parameters of the soil, on the levels of Cd accumulation and on the growth attributes of V. radiata has been assessed. Among the organic amendments, Prosopis charcoal was found to be more effective in reducing the bioavailable levels of Cd in the soil artificially spiked with Cd in graded concentrations of 0, 5, 10, 20, 40, 60, 80 and 100 µg g-1 and its accumulation in V. radiata, thus resulting in an increase in the root, leaf and stem biomass. Coir pith, however, was effective in increasing the total mycorrhizal colonization of roots and second in reducing Cd levels in plants. Therefore, Prosopis charcoal was considered best for stabilization of Cd in soil.

Flow mechanisms in creep of a short-fibre AZ91 alloy-based composite

Czech Academy of Sciences Publication Activity Database

Pahutová, Marie; Sklenička, Václav; Kuchařová, Květa; Svoboda, Milan; Langdon, T. G.

43 2005, č. 1 (2005), s. 34-44 ISSN 0023-432X R&D Projects: GA ČR(CZ) GA106/03/0901 Institutional research plan: CEZ:AV0Z20410507 Keywords : AZ91 magnesium alloy * metal matrix composite * short fibre reinforcement Subject RIV: JG - Metallurgy Impact factor: 0.973, year: 2005

Mechanical spectroscopy of thermal stress relaxation in aluminium alloys reinforced with short alumina fibres

Energy Technology Data Exchange (ETDEWEB)

Carreno-Morelli, E.; Schaller, R. [Ecole Polytechnique Federale, Lausanne (Switzerland). Inst. de Genie Atomique; Urreta, S.E.

1998-05-01

The mechanical behaviour under low temperature thermal cycling of aluminium-based composites reinforced with short Al{sub 2}O{sub 3} SAFFIL fibres has been investigated by mechanical spectroscopy (mechanical loss and elastic shear modulus measurements). A mechanical loss maximum has been observed during cooling which originates in the relaxation of thermal stresses at the interfaces due to the differential thermal expansion between matrix and reinforcement. The maximum height increases with the volumetric fibre content. In addition, if the matrix strength is increased by the appropriated choice of alloy and thermal treatment, the maximum diminishes and shifts to lower temperatures. No damage accumulation at the interfaces has been detected during long period thermal cycling in the range 100 to 500 K. A description of the damping behaviour is made in terms of the development of microplastic zones which surround the fibres. (orig.) 9 refs.

Experimental and kinetic studies on methylene blue adsorption by coir pith carbon.

Science.gov (United States)

Kavitha, D; Namasivayam, C

2007-01-01

Varying the parameters such as agitation time, dye concentration, adsorbent dose, pH and temperature carried out the potential feasibility of thermally activated coir pith carbon prepared from coconut husk for removal of methylene blue. Greater percentage of dye was removed with decrease in the initial concentration of dye and increase in amount of adsorbent used. Kinetic study showed that the adsorption of dye on coir pith carbon was a gradual process. Lagergren first-order, second-order, intra particle diffusion model and Bangham were used to fit the experimental data. Equilibrium isotherms were analysed by Langmuir, Freundlich, Dubnin-Radushkevich, and Tempkin isotherm. The adsorption capacity was found to be 5.87 mg/g by Langmuir isotherm for the particle size 250-500 microm. The equilibrium time was found to be 30 and 60 min for 10 and 20 mg/L and 100 min for 30, 40 mg/L dye concentrations, respectively. A maximum removal of 97% was obtained at natural pH 6.9 for an adsorbent dose of 100 mg/50 mL and 100% removal was obtained for an adsorbent dose of 600 mg/50 mL of 10 mg/L dye concentration. The pH effect and desorption studies suggest that chemisorption might be the major mode of the adsorption process. The change in entropy (DeltaS0) and heat of adsorption (DeltaH0) of coir pith carbon was estimated as 117.20 J/mol/K and 30.88 kJ/mol, respectively. The high negative value of change in Gibbs free energy indicates the feasible and spontaneous adsorption of methylene blue on coir pith carbon.

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.

Three Point Bending of Top-Hat Stiffened Chopped Short Fibre Ramie/HDPE Thermoplastic Composite Beam

Science.gov (United States)

Hadi, Bambang K.; Nuril, Yogie S.

2018-04-01

The use of natural fibre and thermoplastic matrices in composite materials increased significantly during the last decade especially in the automotive industries. Ramie is one of these potential natural fibres. In this paper, a three point bending of top-hat beam made of ramie/HDPE (High-Density-Polyethylene) composites was performed. Top-hat stiffened structures were common structures found in the aerospace industries. Nevertheless, these structures are beginning to be applied in automotive structures in the forms of chassis and bumpers. The ramie/HDPE composite was manufactured using hot-press technique. The temperature was set to be 135°C and the pressure was 6 bars. Chopped short ramie fibre was used, due to good drape ability characteristics. The experiments showed that the beams produced a large non-linearity. Linear Finite Element Analysis was carried out to be compared with the experimental data. The differences are reasonable.

Use of micro-tomography for validation of method to identify interfacial shear strength from tensile tests of short regenerated cellulose fibre composites

DEFF Research Database (Denmark)

Hajlane, A.; Miettinen, A.; Madsen, Bo

2016-01-01

The interfacial shear strength of short regenerated cellulose fibre/polylactide composites was characterized by means of an industry-friendly adhesion test method. The interfacial shear strength was back-calculated from the experimental tensile stress-strain curves of composites by using a micro......-mechanical model. The parameters characterizing the microstructure of the composites, e.g. fibre length and orientation distributions, used as input in the model were obtained by micro-tomography. The investigation was carried out on composites with untreated and surface treated fibres with various fibre weight...

Properties of carbon composite paper derived from coconut coir as a function of polytetrafluoroethylene content

Science.gov (United States)

Destyorini, Fredina; Indriyati; Indayaningsih, Nanik; Prihandoko, Bambang; Zulfia Syahrial, Anne

2018-03-01

The carbon composite papers were produced by utilizing carbon materials from coconut coir. In the present work, carbon composite papers (CCP) were prepared by mixing carbon materials in the form of powder and fibre with polymer (ethylene vinyl acetate and polyethylene glycol) in xylene at 100°C. Then, polytetrafluoroethylene (PTFE) with different content was used to treat the surface of CCP. The properties of PTFE-coated CCP were analysed by means of contact angle measurement, tensile testing, porosity, density, and electrical conductivity measurements. As expected, all CCP’s surfaces treated with PTFE were found to be hydrophobic with contact angle >120° and relatively constant during 60 minutes measurement. Furthermore, water contact angle, density, and mechanical properties of CCP generally increase with increasing PTFE content. However, the porosity and electrical conductivity of CCP decrease slightly as the PTFE content increased from 0 wt% to 30 wt%. Based on the observation and analysis, the optimum PTFE content on CCP was 20 %, in which the mechanical properties and hydrophobicity behaviour were improved significantly, but it was only caused a very small drop in porosity and electrical conductivity

Cocos nucifera coir-mediated green synthesis of Pd NPs and its investigation against larvae and agricultural pest.

Science.gov (United States)

Elango, Ganesh; Mohana Roopan, Selvaraj; Abdullah Al-Dhabi, Naif; Arasu, Mariadhas Valan; Irukatla Damodharan, Kasinathan; Elumalai, Kuppuswamy

2017-12-01

In recent decades, several scientists focused their process towards nanoparticles synthesis by using various sustainable approaches. Cocos nucifera (C. nucifera) was one of the versatile trees in tropical regions which also can act as a thrust quencher in all over the world. Cocos nucifera coir was one of the waste by-products in all coconut-refining industries and with the help C. nucifera coir, Palladium nanoparticles (Pd NPs) were synthesized. Green-synthesized spherical-shape Pd NPs were over layered by secondary metabolites from C. nucifera coir extract and with an average particle size of 62 ± 2 nm, which were confirmed by morphological analysis. Eco-friendly mediated Pd NPs were further subjected to several biological applications like larvicidal against Aedes aegypti (A. aegypti) and anti-feedent, ovicidal, and oviposition deterrent against agricultural pest Callasobruchus maculates (C. maculates) and compared with C. nuciferacoir methanolic extract, which results in LC 50 value of 288.88 ppm and LC 90 value of 483.06 ppm using LSD-Tukey's test against dengue vector (A. aegypti). Cocos nucifera coir methanolic extract shows significant output while compared with Pd NPs towards anti-feedent assays; ovicidal activity and oviposition deterrent were discussed here.

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.

Effect of glass hybridization and staking sequence on mechanical ...

Indian Academy of Sciences (India)

Coir fibre; glass fibre; polyester resin; hybrid laminate; mechanical properties. 1. Introduction. Natural fibres exhibit many advantageous properties as rein- forcement in fibre-reinforced composites. They are low- density materials, yielding relatively light weight composites with specific properties. In an effort to develop a ...

Coir fiber reinforced polypropylene composite panel for automotive interior applications

Science.gov (United States)

Nadir Ayrilmis; Songklod Jarusombuti; Vallayuth Fueangvivat; Piyawade Bauchongkol; Robert H. White

2011-01-01

In this study, physical, mechanical, and flammability properties of coconut fiber reinforced polypropylene (PP) composite panels were evaluated. Four levels of the coir fiber content (40, 50, 60, and 70 % based on the composition by weight) were mixed with the PP powder and a coupling agent, 3 wt % maleic anhydride grafted PP (MAPP) powder. The water resistance and the...

Drying Shrinkage Behaviour of Fibre Reinforced Concrete Incorporating Polyvinyl Alcohol Fibres and Fly Ash

Directory of Open Access Journals (Sweden)

Amin Noushini

2014-01-01

Full Text Available The current study assesses the drying shrinkage behaviour of polyvinyl alcohol fibre reinforced concrete (PVA-FRC containing short-length (6 mm and long-length (12 mm uncoated monofilament PVA fibres at 0.125%, 0.25%, 0.375%, and 0.5% volumetric fractions. Fly ash is also used as a partial replacement of Portland cement in all mixes. PVA-FRC mixes have been compared to length change of control concrete (devoid of fibres at 3 storage intervals: early-age (0–7 days, short-term (0–28 days, and long-term (28–112 days intervals. The shrinkage results of FRC and control concrete up to 112 days indicated that all PVA-FRC mixes exhibited higher drying shrinkage than control. The shrinkage exhibited by PVA-FRC mixes ranged from 449 to 480 microstrain, where this value was only 427 microstrain in the case of control. In addition, the longer fibres exhibited higher mass loss, thus potentially contributing to higher shrinkage.

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.

Effect of Acid mixtures on the Hydrolysis of Coconut Coir for ...

African Journals Online (AJOL)

In this study, coconut coir was hydrolysed to produce fermentable sugars using dilute nitric and acetic acid. The hydrolysis process was carried out according to a four variable Box-Behnken design which was used to develop a statistical model to describe the relationship between the concentration of fermentable sugars ...

Use of sewage sludge and coconut coir mix as a peat substitute for potted chrysanthemum

Energy Technology Data Exchange (ETDEWEB)

Rosenani, A.B.; Lim, F.Y.; Thohirah, L.A.; Fauziah, C.I.

2003-07-01

Recent central processing of domestic wastewater in Malaysia has initiated investigations into the disposal/utilization of the sewage sludge produced. We had conducted an experiment to investigate the feasibility of using dewatered sewage sludge and coconut coir as a peat substitute in a potting medium for chrysanthemum. The experiment involved 9 treatments with sewage sludge (SS) and coconut coir (CC) mixed in different ratios (v/v) to replace peat in the standard potting medium of 3:2:1 (soil: peat: sand).The potting medium contained the following treatments, T1: peat + recommended rates of Agroblend (Ag), a slow release fertilizer, and Grofas (Gf), a foliar fertilizer (commonly used medium and fertilization), T2: [1SS:1CC] + Ag, T3: [1SS:1CC] + half recommended rates of Agroblend and Grofas (1/2Ag + 1/2Gf), T4: [2SS:1CC] + Ag, T5: [2SS:1CC] + 1/2Ag + 1/2Gf, T6: [3SS:1CC] + Ag, T7: [3SS:1CC] + 1/2Ag + 1/2Gf, T8: [4SS:1CC] + Ag, and T9: [4SS:1CC] + 1/2Ag + 1/2Gf; laid-out in a randomized complete block design with 5 replications. Results of the study show that in general the media with sludge and coconut coir mixtures produced better plant growth and higher total number of flowers than peat. However, the higher ratio of SS:CC, (4SS:1CC) produced poorer plant growth and less number of flowers. Increase in sewage sludge in the medium resulted in increase in foliar contents of heavy metals. This study demonstrates that sewage sludge and coconut coir mixture in the ratio of 1:1 may best substitute peat in the potting medium for chrysanthemum with only Agroblend fertilizer application. (author)

Coir pith of the green coconut in the decontamination of radioactive aqueous effluent

Energy Technology Data Exchange (ETDEWEB)

Monteiro, Raquel Almeida; Yamaura, Mitiko [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)]. E-mail: quequelll_monteiro@yahoo.com.br; myamaura@ipen.br

2007-07-01

Industrial segments as plant of mining, hospitals and university generate considerable volumes of radioactive wastewater containing uranium. The increasing development of the use of the nuclear energy to lead away to an expansion of the sectors of the nuclear fuel cycle, but it leads to security problems and it appears the necessity of control of the removing of uranium and radioactive effluent treatments. Researches evaluate if the technique of the biosorption would promote an alternative process with attractive characteristics of cost-benefit. The residual biomass from agricultural activities has been studied and used as adsorbent of metals and organic composts by low cost, abundance and for being biodegradable. In this work, it is presented the efficiency of the coir pith for the adsorption of ions UO{sub 2}{sup 2+}. The coir pith is a by-product of the harvest of the coconut, a renewable natural source. The study was accomplished using the batch techniques. The influence from pH 2 to 5, the dose of the coir pith, equilibrium time and the models of kinetic reaction were investigated. It was verified that the adsorption increased with the increase of pH and of the dose. The equilibrium time was of 30 min and the best correspondence with the model of pseudo second-order was observed. The results obtained has been promising, so use as adsorbent of metallic ions represents an economic alternative in relation to the conventional treatment of effluent. (author)

Coir pith of the green coconut in the decontamination of radioactive aqueous effluent

International Nuclear Information System (INIS)

Monteiro, Raquel Almeida; Yamaura, Mitiko

2007-01-01

Industrial segments as plant of mining, hospitals and university generate considerable volumes of radioactive wastewater containing uranium. The increasing development of the use of the nuclear energy to lead away to an expansion of the sectors of the nuclear fuel cycle, but it leads to security problems and it appears the necessity of control of the removing of uranium and radioactive effluent treatments. Researches evaluate if the technique of the biosorption would promote an alternative process with attractive characteristics of cost-benefit. The residual biomass from agricultural activities has been studied and used as adsorbent of metals and organic composts by low cost, abundance and for being biodegradable. In this work, it is presented the efficiency of the coir pith for the adsorption of ions UO 2 2+ . The coir pith is a by-product of the harvest of the coconut, a renewable natural source. The study was accomplished using the batch techniques. The influence from pH 2 to 5, the dose of the coir pith, equilibrium time and the models of kinetic reaction were investigated. It was verified that the adsorption increased with the increase of pH and of the dose. The equilibrium time was of 30 min and the best correspondence with the model of pseudo second-order was observed. The results obtained has been promising, so use as adsorbent of metallic ions represents an economic alternative in relation to the conventional treatment of effluent. (author)

Optimization of mechanical properties of non-woven short sisal fibre ...

Indian Academy of Sciences (India)

fibre-reinforced vinyl ester composite using factorial design and GA method ... fibre is extracted from the plant Agave sisalana and is avai- lable in abundant quantity ..... Sotton M and Ferrari M 1989 L'industrie Textile 1197 58. Woodhams R T ...

Photonic crystal fibre enables short-wavelength two-photon laser scanning fluorescence microscopy with fura-2

International Nuclear Information System (INIS)

McConnell, Gail; Riis, Erling

2004-01-01

We report on a novel and compact reliable laser source capable of short-wavelength two-photon laser scanning fluorescence microscopy based on soliton self-frequency shift effects in photonic crystal fibre. We demonstrate the function of the system by performing two-photon microscopy of smooth muscle cells and cardiac myocytes from the rat pulmonary vein and Chinese hamster ovary cells loaded with the fluorescent calcium indicator fura-2/AM

Coconut coir as biosorbent for Cr(VI) removal from laboratory wastewater.

Science.gov (United States)

Gonzalez, Mário H; Araújo, Geórgia C L; Pelizaro, Claudia B; Menezes, Eveline A; Lemos, Sherlan G; de Sousa, Gilberto Batista; Nogueira, Ana Rita A

2008-11-30

A high cost-effective treatment of sulphochromic waste is proposed employing a raw coconut coir as biosorbent for Cr(VI) removal. The ideal pH and sorption kinetic, sorption capacities, and sorption sites were the studied biosorbent parameters. After testing five different isotherm models with standard solutions, Redlich-Peterson and Toth best fitted the experimental data, obtaining a theoretical Cr(VI) sorption capacity (SC) of 6.3 mg g(-1). Acid-base potentiometric titration indicated around of 73% of sorption sites were from phenolic compounds, probably lignin. Differences between sorption sites in the coconut coir before and after Cr adsorption identified from Fourier transform infrared spectra suggested a modification of sorption sites after sulphochromic waste treatment, indicating that the sorption mechanism involves organic matter oxidation and chromium uptake. For sulphocromic waste treatment, the SC was improved to 26.8+/-0.2 mg g(-1), and no adsorbed Cr(VI) was reduced, remaining only Cr(III) in the final solution. The adsorbed material was calcinated to obtain Cr(2)O(3,) with a reduction of more than 60% of the original mass.

Recycling of agricultural solid waste, coir pith: Removal of anions, heavy metals, organics and dyes from water by adsorption onto ZnCl2 activated coir pith carbon

International Nuclear Information System (INIS)

Namasivayam, C.; Sangeetha, D.

2006-01-01

The abundant lignocellulosic agricultural waste, coir pith is used to develop ZnCl 2 activated carbon and applied to the removal of toxic anions, heavy metals, organic compounds and dyes from water. Sorption of inorganic anions such as nitrate, thiocyanate, selenite, chromium(VI), vanadium(V), sulfate, molybdate, phosphate and heavy metals such as nickel(II) and mercury(II) has been studied. Removal of organics such as resorcinol, 4-nitrophenol, catechol, bisphenol A, 2-aminophenol, quinol, O-cresol, phenol and 2-chlorophenol has also been investigated. Uptake of acidic dyes such as acid brilliant blue, acid violet, basic dyes such as methylene blue, rhodamine B, direct dyes such as direct red 12B, congo red and reactive dyes such as procion red, procion orange were also examined to assess the possible use of the adsorbent for the treatment of contaminated ground water. Favorable conditions for maximum removal of all adsorbates at the adsorbate concentration of 20 mg/L were used. Results show that ZnCl 2 activated coir pith carbon is effective for the removal of toxic pollutants from water

Debonding of short fibres among particulates in a metal matrix composite

DEFF Research Database (Denmark)

Tvergaard, Viggo

2003-01-01

of differently shaped fibres or particulates in each unit cell. thus representing debonding of a relatively long discontinuous fibre among particulates that do not debond. Interfacial failure is modelled in terms of a cohesive zone model that accounts for decohesion by normal separation as well as by tangential...... separation. It is found that the evolution of failure can depend rather strongly on the distribution of particulates around a fibre subject to debonding. (C) 2003 Elsevier Ltd. All rights reserved....

Cytocompatibility and Mechanical Properties of Short Phosphate Glass Fibre Reinforced Polylactic Acid (PLA Composites: Effect of Coupling Agent Mediated Interface

Directory of Open Access Journals (Sweden)

Gavin Walker

2012-10-01

Full Text Available In this study three chemical agents Amino-propyl-triethoxy-silane (APS, sorbitol ended PLA oligomer (SPLA and Hexamethylene diisocyanate (HDI were identified to be used as coupling agents to react with the phosphate glass fibre (PGF reinforcement and the polylactic acid (PLA polymer matrix of the composite. Composites were prepared with short chopped strand fibres (l = 20 mm, ϕ = 20 µm in a random arrangement within PLA matrix. Improved, initial composite flexural strength (~20 MPa was observed for APS treated fibres, which was suggested to be due to enhanced bonding between the fibres and polymer matrix. Both APS and HDI treated fibres were suggested to be covalently linked with the PLA matrix. The hydrophobicity induced by these coupling agents (HDI, APS helped to resist hydrolysis of the interface and thus retained their mechanical properties for an extended period of time as compared to non-treated control. Approximately 70% of initial strength and 65% of initial modulus was retained by HDI treated fibre composites in contrast to the control, where only ~50% of strength and modulus was retained after 28 days of immersion in PBS at 37 °C. All coupling agent treated and control composites demonstrated good cytocompatibility which was comparable to the tissue culture polystyrene (TCP control, supporting the use of these materials as coupling agent’s within medical implant devices.

Analysis of filler--fibre interaction in fly ash filled short fibre-epoxy ...

Indian Academy of Sciences (India)

Size and aspect ratio are believed to influence the rheology or the flow in the mixture and in turn the mechanical performance of the composites. Fillers and fibres when used in combination are expected to complement each other's performance resulting in better properties for the composite. They also reduce the extent of ...

Assessment of Cadmium (II) and Chromium (VI) removal from aqueous solution using coconut “Cocosnucifera” Coir as biosorbent in batch and fixed-bed column adsorption

International Nuclear Information System (INIS)

Capili, M.L.S.; Escover, J.J.; San Miguel, J.A.N.; Duavis, A.G.; Sucgang, R.J.

2015-01-01

Heavy metals from industrial effluents are considered contaminants and pose various health risks. Coconut coir is an agricultural waste material abundantly found in the Philippines and is a potential biosorbent of heavy metals. The adsorption of cadmium (II) and chromium (VI) in aqueous solutions were studied under different parameters using coconut coir as the adsorbent. The properties of coconut coir such as crystalline and morphological structure, along with the functional groups present were determined using XRD, SEM and FTIR respectively. The effect of solution pH, initial metal ion concentration and adsorbent dose were determined and optimized concentration of each solution was carried out using AAS. XRF was done to prove that the decrease of metal concentration in the solution was due to the adsorption of the coir. The data obtained from the optimum parameter of each metal were fitted to the Freundlich and Langmuir isotherm models as well as Elovich, first-order and second-order Lagergren kinetic models. These parameters were also used for the adsorption column experiment to determine and compare the adsorption capacity of the coir when applied to a continuous process. Removal optimum parameters for cadmium were at pH 4, initial metal ion concentration of 0.2 mg/L and 0.6g adsorbent dose with a removal efficiency of 99.62%. Optimum parameters for chromium were obtained at pH 5, initial metal ion concentration of 1.2 mg/L and 1g adsorbent dose with a removal efficiency 10.52%. The study indicated that coconut coir is significantly effective in the adsorption of cadmium ions in aqueous solutions than chromium ions based on the reported removal efficiency.(author)

Nitrogen utilisation of lowland cauliflower grown on coconut coir dust

International Nuclear Information System (INIS)

Asiah Ahmad

2004-01-01

Strong wind, high rainfall, the spread of diseases during rainy season and pests problems in open field agriculture have led to the current trend in growing vegetables under protected environment. The occurrence of soil borne disease, and limited suitable land for agriculture are some of the reasons to look for alternative media such as coconut coir dust. The basic properties of coconut coir dust as a soil less growing medium and the utilisation of nitrogen (n) fertiliser for the lowland cauliflower grown in them have not been thoroughly investigated and are therefore not well understood. This study has been conducted by the need to provide a basis for determining optimal levels/ concentration and forms of nitrogen supply, and by the need to minimize environmental consequences of lowland cauliflower production. It focuses on the effects of N supply in terms of different levels of N and ionic N forms in the nutrient solution, on the growth, development and N utilisation of cauliflower grown in coconut coir dust under greenhouse condition in the lowlands. Based on the plant growth parameters studied coconut coir dust was found to be more suitable than oil palm empty fruit bunch as a growing medium. From the growth and development study using coconut coir dust, it can be deduced that the N requirement by the plant is less at later growth stage regardless of low or high level of N in the nutrient solution. However, low level of N of 50 mg l -1 was found to be inadequate for plant growth and curd yield. The N concentration levels of 200 mg l -1 in the nutrient solution optimised both the vegetative and curd production. A somewhat lower level of N (170 mg l -1 ) produced curd weight not significantly different from N level of 200 mg l -1 . The plant growth and curd yield was reduced by about 29.0 % at 400 mg N l -1 . The N level of 400 mg l -1 in the nutrient solution may be in excess to that actually required by the plant, resulting in a high unused N nutrient

Composite Strain Hardening Properties of High Performance Hybrid Fibre Reinforced Concrete

Directory of Open Access Journals (Sweden)

Vikram Jothi Jayakumar

2014-01-01

Full Text Available Hybrid fibres addition in concrete proved to be a promising method to improve the composite mechanical properties of the cementitious system. Fibre combinations involving different fibre lengths and moduli were added in high strength slag based concrete to evaluate the strain hardening properties. Influence of hybrid fibres consisting of steel and polypropylene fibres added in slag based cementitious system (50% CRL was explored. Effects of hybrid fibre addition at optimum volume fraction of 2% of steel fibres and 0.5% of PP fibres (long and short steel fibre combinations were observed in improving the postcrack strength properties of concrete. Test results also indicated that the hybrid steel fibre additions in slag based concrete consisting of short steel and polypropylene (PP fibres exhibited a the highest compressive strength of 48.56 MPa. Comparative analysis on the performance of monofibre concrete consisting of steel and PP fibres had shown lower residual strength compared to hybrid fibre combinations. Hybrid fibres consisting of long steel-PP fibres potentially improved the absolute and residual toughness properties of concrete composite up to a maximum of 94.38% compared to monofibre concrete. In addition, the relative performance levels of different hybrid fibres in improving the matrix strain hardening, postcrack toughness, and residual strength capacity of slag based concretes were evaluated systematically.

Additive Layer Manufacturing of Biologically Inspired Short Fibre Reinforced Composites

Science.gov (United States)

2014-03-01

ductile  fibre   coating  with  enhanced  mechanical...data   for   us   to   critically   assess   the   prospect   of   nanorod-­‐ coated   fibres  for  improved   ductility  in...fully   coated  with   zinc  acetate  seeds,  substrates   are  typically  dipped  in  the  solution  several  times

Coconut coir pith lignin: A physicochemical and thermal characterization.

Science.gov (United States)

Asoka Panamgama, L; Peramune, P R U S K

2018-07-01

The structural and thermal features of coconut coir pith lignin, isolated by three different extraction protocols incorporating two different energy supply sources, were characterized by different analytical tools. The three different chemical extraction protocols were alkaline - 7.5% (w/v) NaOH, organosolv - 85% (v/v) formic and acetic acids at 7:3 (v/v) ratio and polyethylene glycol (PEG): water ratio at 80:20wt%. The two sources of energy were thermal or microwave. Raw lignins were modified by epichlorohydrin to enhance reactivity, and the characteristics of raw and modified lignins were comparatively analysed. Using the thermal energy source, the alkaline and organosolv processes obtained the highest and lowest lignin yields of 26.4±1.5wt% and 3.4±0.2wt%, respectively, as shown by wet chemical analysis. Specific functional group analysis by Fourier transform infrared spectra (FTIR) revealed that significantly different amounts of hydroxyl and carbonyl groups exist in alkaline, organosolv and PEG lignins. Thermogravimetric analysis (TGA) illustrated that the lowest degradation onset temperature was recorded for organosolv lignin, and the overall order was organosolvcoir pith can be performed efficiently with several protocols and that those methods offer practical value to industry. Copyright © 2018 Elsevier B.V. All rights reserved.

Nitrogen utilisation of lowland cauliflower grown on coconut coir dust

Energy Technology Data Exchange (ETDEWEB)

Ahmad, Asiah

2004-07-01

Strong wind, high rainfall, the spread of diseases during rainy season and pests problems in open field agriculture have led to the current trend in growing vegetables under protected environment. The occurrence of soil borne disease, and limited suitable land for agriculture are some of the reasons to look for alternative media such as coconut coir dust. The basic properties of coconut coir dust as a soil less growing medium and the utilisation of nitrogen (n) fertiliser for the lowland cauliflower grown in them have not been thoroughly investigated and are therefore not well understood. This study has been conducted by the need to provide a basis for determining optimal levels/ concentration and forms of nitrogen supply, and by the need to minimize environmental consequences of lowland cauliflower production. It focuses on the effects of N supply in terms of different levels of N and ionic N forms in the nutrient solution, on the growth, development and N utilisation of cauliflower grown in coconut coir dust under greenhouse condition in the lowlands. Based on the plant growth parameters studied coconut coir dust was found to be more suitable than oil palm empty fruit bunch as a growing medium. From the growth and development study using coconut coir dust, it can be deduced that the N requirement by the plant is less at later growth stage regardless of low or high level of N in the nutrient solution. However, low level of N of 50 mg l{sup -1} was found to be inadequate for plant growth and curd yield. The N concentration levels of 200 mg l{sup -1} in the nutrient solution optimised both the vegetative and curd production. A somewhat lower level of N (170 mg l{sup -1}) produced curd weight not significantly different from N level of 200 mg l{sup -1}. The plant growth and curd yield was reduced by about 29.0 % at 400 mg N l{sup -1}. The N level of 400 mg l{sup -1} in the nutrient solution may be in excess to that actually required by the plant, resulting in a high

Muscle architecture and fibre characteristics of rat gastrocnemius and semimembranosus muscles during isometric contractions.

Science.gov (United States)

Huijing, P A; van Lookeren Campagne, A A; Koper, J F

1989-01-01

Rat gastrocnemius medialis (GM) and semimembranosus (SM) muscles have a very different morphology. GM is a very pennate muscle, combining relatively short muscle fibre length with sizable fibre angles and long muscle and aponeurosis lengths. SM is a more parallel-fibred muscle, combining a relatively long fibre length with a small fibre angle and short aponeurosis length. The mechanisms of fibre shortening as well as angle increase are operational in GM as well as SM. However, as a consequence of isometric contraction, changes of fibre length and angle are greater for GM than for SM at any relative muscle length. These differences are particularly notable at short muscle lengths: at 80% of optimum muscle length, fibre length changes of approximately 30% are coupled to fibre angle changes of 15 degrees in GM, while for SM these changes are 4% and 0.6 degrees, respectively. A considerable difference was found for normalized active slack muscle length (GM approximately 80 and SM approximately 45%). This is explained by differences of degree of pennation as well as factors related to differences found for estimated fibre length-force characteristics. Estimated normalized active fibre slack length was considerably smaller for SM than for GM (approximately 40 and 60%, respectively). The most likely explanation of these findings are differences of distribution of optimum fibre lengths, possibly in combination with differences of myofilament lengths and/or fibre length distributions.

Deflection hardening behaviour of short fibre reinforced fly ash based geopolymer composites

International Nuclear Information System (INIS)

Shaikh, F.U.A.

2013-01-01

Highlights: • Deflection hardening behaviour is achieved in the DFRGC similar to that observed in DFRCC. • The first crack load or in other word the limit of proportionality (LOP) of DFRGC is similar to that of DFRCC. • The DFRGC also exhibited higher deflection at peak load than DFRCC. • The toughness at peak load of DFRGC is also high than that of DFRCC. • The ductility of DFRGC is also higher than that of DFRCC. - Abstract: This paper reports the newly developed ductile fibre reinforced geopolymer composite (DFRGC) exhibiting deflection hardening and multiple cracking behaviour. The binder of the above composite is different from that used in conventional cement based system. The class F fly ash is used instead of Portland cement in DFRGC and is activated by alkaline liquids (sodium hydroxide and sodium silicate). In this study, two types of fibres namely steel (ST) and polyvinyl alcohol (PVA) fibres are used in mono as well as in ST–PVA hybrid form, with a total volume fraction of 2%. The deflection hardening behaviour of newly developed DFRGC is also compared with that of conventional ductile fibre reinforced cementitious composites (DFRCC). The effects of two different sizes of sand (1.18 mm, and 0.6 mm) and sand/binder ratios of 0.5 and 0.75 on the deflection hardening and multiple cracking behaviour of both DFRGC and DFRCC are also evaluated. Results revel that the deflection hardening and multiple cracking behaviour is achieved in geopolymer based DFRGC similar to that of cement based system. For a given sand size and sand content, comparable deflection hardening behaviour, ultimate flexural strength and the deflection at peak load are observed in both cement and geopolymer based composites irrespective of fibre types and combination. The deflection hardening behaviour of DFRGC is also confirmed by the calculated toughness index values of I 20 > 20. The scanning electron microscope (SEM) study shows no degradation of PVA and steel fibres in the

Asbestos as 'toxic short-circuit' optic-fibre for UV within the cell-net: — Likely roles and hazards for secret UV and IR metabolism

International Nuclear Information System (INIS)

Traill, Robert R

2011-01-01

The most toxic asbestos fibres have widths 250nm-10nm, and this toxicity is 'physical', which could mean either mechanical or optical: Tangling with chromosomes is a mechanical hazard occasionally reported, and fibres 100nm wide — or chrysotile (white asbestos) is >150nm. In both cases, UV A /UV B -transmission would then predominate. (Chrysotile 150nm might be benign — escaping both mechanical and optical!). But what would generate such UV, and why would its transmission be toxic? Thar and Kühl (J.Theor.Biol.:2004) explain that the long mitochondria on microtubules may be able to act as UV-lasers, (and many observers since Gurwitsch 1923 have reported ultraweak UV emissions escaping from all types of living bio-tissue). That all suggests some universal secret role for UV, apparently related to mitosis. Insertion of fibre 'short-circuits' could then cause upsets in mitosis-control, and hence DNA irregularities. Such UV-control could parallel similar lower-powered Infra-Red control-systems (as considered elsewhere for coaxial myelin; or as portrayed by G.Albrecht-Buehler's online animations etc.); and the traditional short mitochondria seem better suited for this IR task.

Influence of fibre treatments on mechanical properties of short Sansevieria cylindrica/polyester composites

International Nuclear Information System (INIS)

Sreenivasan, V.S.; Ravindran, D.; Manikandan, V.; Narayanasamy, R.

2012-01-01

Highlights: ► Fibre treatments were performed to improve interfacial bond between SCF and matrix. ► Mechanical properties of treated SCFP composites are greater than USCFP composites. ► PSCFP composites show maximum mechanical properties among treated SCFP composites. ► SEM analysis revealed that the wetting of PSCFs by the polyester resin was good. ► KMnO 4 treatment is ideal treatment for SCFs to get optimum mechanical properties. -- Abstract: In the present study, to improve the interfacial bond between Sansevieria cylindrica fibres (SCFs) and polyester matrix, chemical surface treatments have been performed on the fibres. Treatments including alkali, benzoyl peroxide, potassium permanganate and stearic acid were carried out to modify the fibre surface. Raw and each type of treated SCF samples were utilised separately for fabricating the composites. The mechanical properties of composites prepared from the chemically treated SCFs are found to be much better than those of the untreated ones. Potassium-permanganate-treated S. cylindrica fibre/polyester (PSCFP) composites showed optimum mechanical properties among the treated S. cylindrica fibre/polyester (SCFP) composites. The surface morphologies of fracture surfaces of composites were recorded using scanning electron microscopy (SEM). The SEM micrographs reveal that interfacial bonding between potassium-permanganate-treated SCF (PSCF) and polyester matrix has significantly improved, suggesting that better dispersion of PSCF into the matrix has occurred upon potassium permanganate treatment of SCF.

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...

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

Multibeam Fibre Laser Cutting

DEFF Research Database (Denmark)

Olsen, Flemming Ove

The appearance of the high power high brilliance fibre laser has opened for new possibilities in laser materials processing. In laser cutting this laser has demonstrated high cutting performance compared to the dominating cutting laser, the CO2-laser. However, quality problems in fibre......-laser cutting have until now limited its application in metal cutting. In this paper the first results of proof-of-principle studies applying a new approach (patent pending) for laser cutting with high brightness short wavelength lasers will be presented. In the approach, multi beam patterns are applied...... to control the melt flow out of the cut kerf resulting in improved cut quality in metal cutting. The beam patterns in this study are created by splitting up beams from 2 single mode fibre lasers and combining these beams into a pattern in the cut kerf. The results are obtained with a total of 550 W of single...

Winding of fibre composites; Vikling af fiberkompositter

Energy Technology Data Exchange (ETDEWEB)

Lystrup, Aage

2006-01-01

Within the project 'Storage of hydrogen in advanced high pressure vessels' under the PSO-R AND D 2005 program one of the tasks is to describe the technology, which is used for manufacturing of fibre reinforced pressure vessels. Fibre reinforced pressure vessels for high pressures are manufactured by winding structural load bearing fibres around a mandrel or an internal liner. There are two different types of cylindrical pressure vessels: 1) Cylinders with thick metal liner, where only the cylindrical part is over wrapped with hoop windings, and 2) cylinders with a thin metal or polymer liner, where both the cylindrical part and the end domes are over wrapped with more layers with different fibre orientations (helical and hoop windings). This report describes the fundamental principles for filament winding of fibre reinforced polymer composites. After a short introduction to the advanced fibre composites, their properties and semi-raw materials used for fibre composites, the focus is on the process parameters, which have influence on the material quality of filament wound components. The report is both covering winding of fibre reinforced thermo-setting polymers as well as thermoplastic polymers, and there are references to vendors of filament winding machines, accessory equipment and computer software for design and manufacturing of filament wound components. (au)

Mechanical properties evaluation of single and hybrid composites polyester reinforced bamboo, PALF and coir fiber

Science.gov (United States)

Rihayat, T.; Suryani, S.; Fauzi, T.; Agusnar, H.; Wirjosentono, B.; Syafruddin; Helmi; Zulkifli; Alam, P. N.; Sami, M.

2018-03-01

This study aims to determine the composition fiber natural of bamboo, pineapple leaf and coir in single and hybrid composite to see the best characteristics of tensile strength and flexural test by using a Universal Testing Machine (UTM) and observe the effect on the microstructure of the composite through optical and scanning electron microscopy. Bamboo, Palf and coir have synthesis from natural fiber was used as reinforcement in polyester composite using hand lay up or a hot-compression moulding while filler:matrix was used (45%:55wt.%, 70%:30wt.% and 15%:85wt.%). From the variation of the volume fraction between filler and matrix show that mechanical properties of composites increased with increasing amount of filler in the matrix. This is evidenced by the high mechanical properties A:B:C/Ps in compositions 45%: 55wt.% 136 Mpa while flexural strength 93 N and good structure surface morphology. This research has produced a hybrid composite materials that have high mechanical properties and bending compared with conventional synthetic fibers and other materials.

Natural fibre reinforced non-asbestos organic non-metallic friction composites: effect of abaca fibre on mechanical and tribological behaviour

Science.gov (United States)

Liu, Yucheng; Ma, Yunhai; Che, Junjian; Duanmu, Lingjian; Zhuang, Jian; Tong, Jin

2018-05-01

To obtain a natural fibre reinforced non-asbestos organic non-metallic friction composite with good wear resistance and environmental-friendly performances, friction composites reinforced with different lengths of abaca fibre were fabricated by a compression molder equipment and evaluated by using a constant-speed friction test machine. The worn surface morphologies were observed and analyzed using a Scanning Electron Microscopy (SEM). Experimental results show that the length of abaca fibre had no significant effect on the density and hardness, but was obvious on impact strength. The impact strength increased and then decreased with the increasing of length of abaca fibres. Abaca fibres, especially short fibre (lengths of 5 mm, 10 mm), could improve the wear resistance of the friction composites. Meanwhile, the increase of test temperature could result in the increasing of wear rates of the friction composites. A large amount of secondary plateaux presented on the worn surface of specimens FC1 and FC2 which showe relatively smooth worn surfaces and yield the better wear resistance performance.

Removal and recovery of molybdenum from aqueous solutions by adsorption onto Surfactant-Modified coir pith, a lignocellulosic polymer

Energy Technology Data Exchange (ETDEWEB)

Namasivayam, Chinnaiya [Environmental Chemistry Division, Department of Environmental Sciences, Bharathiar University, Coimbatore (India); Sureshkumar, Molagoundanpalayam Venkatachalam [Department of Chemistry, PARK College of Engineering and Technology, Coimbatore (India)

2009-01-15

Coconut coir pith, a lignocellulosic polymer, is an unwanted by-product of the coir fiber industry. The pith was used as a biosorbent for the removal of Molybdenum(VI) after modification with a cationic surfactant, hexadecyltrimethylammonium bromide. The optimum pH for maximum adsorption of Mo(VI) was found to be 3.0. Langmuir, Freundlich and Dubinin Radushkevich isotherms were used to model the adsorption equilibrium data and the system was seen to follow all three isotherms. The Langmuir adsorption capacity of the biosorbent was found to be 57.5 mg g{sup -1}. Kinetic studies showed that the adsorption generally obeyed a second-order kinetic model. Desorption studies showed that the recovery of Mo(VI) from the spent adsorbent was feasible. The effect of foreign anions on the adsorption of Mo(VI) was also examined. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

Stress strain modelling and analysis of a piezo-coated optical fibre sensor

Science.gov (United States)

Al-Raweshidy, H.; Ali, H.; Obayya, S. S. A.; Langley, R.; Batchelor, J.

2005-02-01

A finite element model, using commercially available software, is presented to simulate the piezoelectrically induced stresses and strains in an optical fibre to be used as antenna. These stresses and strains are generated by a layer of piezoelectric polymer deposited on the cladding of a short fibre sample. The theoretical basis for the work is briefly explained and the modelling process is emphasised. Two types of fibre are investigated - circular fibre and D-fibre, and the results compared, analysed and discussed. It is shown that in the D-fibre, the stress and displacement increased by 1.46 and 115 times, respectively, in comparison with the circular fibre.

Controlled light localisation and nonlinear-optical interactions of short laser pulses in holey fibres

International Nuclear Information System (INIS)

Fedotov, Andrei B; Zheltikov, Aleksei M; Golovan', Leonid A; Kashkarov, Pavel K; Tarasevitch, A P; Podshivalov, Alexey A; Alfimov, Mikhail V; Ivanov, Anatoliy A; Beloglazov, V I; Haus, J W; Linde, D von der

2001-01-01

The influence of the structure of holey-fibre cladding on the effective waveguide mode area and the spectral broadening of femtosecond pulses of titanium-sapphire and forsterite lasers is experimentally studied. These experiments demonstrate that the increase in the air-filling fraction of the holey-fibre cladding may substantially enhance the spectral broadening of laser pulses due to the increase in the degree of light localisation in the fibre core. (femtosecond technologies)

Crystallization of the C-terminal head domain of the avian adenovirus CELO long fibre

Energy Technology Data Exchange (ETDEWEB)

Guardado Calvo, Pablo [Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Santiago de Compostela, Campus Sur, E-15782 Santiago de Compostela (Spain); Llamas-Saiz, Antonio L. [Unidad de Difracción de Rayos X, Laboratorio Integral de Dinámica y Estructura de Biomoléculas José R. Carracido, Edificio CACTUS, Universidad de Santiago de Compostela, Campus Sur, E-15782 Santiago de Compostela (Spain); Langlois, Patrick [Agence Francaise de Securité Sanitaire des Aliments, Unité Génétique Virale et Biosecurité, Site Les Croix, BP 53, F-22440 Ploufragan (France); Raaij, Mark J. van, E-mail: vanraaij@usc.es [Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Santiago de Compostela, Campus Sur, E-15782 Santiago de Compostela (Spain); Unidad de Difracción de Rayos X, Laboratorio Integral de Dinámica y Estructura de Biomoléculas José R. Carracido, Edificio CACTUS, Universidad de Santiago de Compostela, Campus Sur, E-15782 Santiago de Compostela (Spain)

2006-05-01

Avian adenovirus long-fibre head trimers were expressed, purified and crystallized. The crystals belong to space group C2 (unit-cell parameters a = 216.5, b = 59.2, c = 57.5 Å, β = 101.3°). A complete highly redundant data set was collected to 2.2 Å resolution at 100 K using a rotating-anode X-ray source. Avian adenovirus CELO contains two different fibres: fibre 1, the long fibre, and fibre 2, the short fibre. The short fibre is responsible for binding to an unknown avian receptor and is essential for infection of birds. The long fibre is not essential, but is known to bind the coxsackievirus and adenovirus receptor protein. Both trimeric fibres are attached to the same penton base, of which each icosahedral virus contains 12 copies. The short fibre extends straight outwards, while the long fibre emerges at an angle. The carboxy-terminal amino acids 579–793 of the avian adenovirus long fibre have been expressed with an amino-terminal hexahistidine tag and the expressed trimeric protein has been purified by nickel-affinity chromatography and crystallized. Crystals were grown at low pH using PEG 10 000 as precipitant and belonged to space group C2. The crystals diffracted rotating-anode Cu Kα radiation to at least 1.9 Å resolution and a complete data set was collected from a single crystal to 2.2 Å resolution. Unit-cell parameters were a = 216.5, b = 59.2, c = 57.5 Å, β = 101.3°, suggesting one trimer per asymmetric unit and a solvent content of 46%. The long fibre head does not have significant sequence homology to any other protein of known structure and molecular-replacement attempts with known fibre-head structures were unsuccessful. However, a map calculated using SIRAS phasing shows a clear trimer with a shape similar to known adenovirus fibre-head structures. Structure solution is in progress.

Effect of the doped fibre length on soliton pulses of a bidirectional mode-locked fibre laser

Energy Technology Data Exchange (ETDEWEB)

Ahmad, H; Alwi Kutty, N A; Zulkifli, M Z; Harun, S W [Photonics Research Center (Department of Physics), University of Malaya, 50603 Kuala Lumpur (Malaysia)

2015-08-31

A passively bidirectional mode-locked fibre laser is demonstrated using a highly concentrated erbium-doped fibre (EDF) as a gain medium. To accomplish mode-locked operation in a short cavity, use is made of carbon nanotubes (CNTs) as a saturable absorber. Soliton pulses are obtained at a wavelength of 1560 nm with a repetition rate ranging from 43.92 MHz to 46.97 MHz and pulse width stretching from 0.56 ps to 0.41 ps as the EDF length is reduced from 60 cm to 30 cm. (lasers)

Effect Application of Sea Sand, Coconut and Banana Coir on the Growth and Yield of Rice Planted at Ustic Endoaquert Soil

Directory of Open Access Journals (Sweden)

Nurdin

2014-06-01

Full Text Available The research was aimed to study effect application of sea sand (SS, coconut coir (CC and banana coir (BC on the growth and yield of rice (Oryza sativa L. planted at Ustic Endoaquert soil. The pot experiment was carried out using a factorial design with 3 factors. The first factor was SS consisted of three levels i.e.: 0%, 25%, and 50%. The second and third factors were CC and BC, each consisted of three levels i.e.: 0, 10, and 20 Mg ha-1. Application of SS and BC significantly increased leaf length where the highest increasing percentage was 16.47% which was achieved at 25% SS application. Their effect on leaf numbers and tiller numbers were relatively not similar pattern where leaf number only increased about 65.52% by BC application, while tiller numbers only increased about 10.77% by SS application. Furthermore, the application of CC and BC significantly increased panicle numbers to 29.53% and 29.05%, respectively compared to control. All ameliorants significantly increased panicle numbers, but the best was CC with the increasing up to 46.49% at 20 Mg ha-1 CC compared to SS or BC application. However, only coconut coir significantly increased the rice grain numbers.

Refractive Index Measurement within a Photonic Crystal Fibre Based on Short Wavelength Diffraction

Directory of Open Access Journals (Sweden)

Nathaniel Groothoff

2007-10-01

Full Text Available A new class of refractive index sensors using solid core photonic crystal fibres isdemonstrated. Coherent scattering at the cladding lattice is used to optically characterizematerials inserted into the fibre holes. The liquid to solid phase transition of water uponfreezing to ice 1h is characterized by determining the refractive index.

The environmental impact of fibre crops in industrial applications

NARCIS (Netherlands)

Dam, van J.E.G.; Bos, H.L.

2004-01-01

A short literature survey is presented on health and environmental issues in relation to the production and use of fibre crops. Next a short introduction to Life Cycle Analysis (LCA) is given and the various commonly applied methods for quantifying ecological impacts are discussed in short. The

Regeneration of irradiated optical fibres by photo-bleaching?

International Nuclear Information System (INIS)

Henschel, H.; Koehn, O.

1999-01-01

It is known that a light power between 0,1 and 20 μW caused bleaching of colour centres, which implies a reduction of induced loss. Older fibres especially those with a core made of undoped, low OH silica, experience tremendous photo-bleaching. Light of shorter wavelengths has a higher bleaching efficiency than that of longer wavelengths and same light intensity. The investigations have demonstrated that the injection of photo-bleaching light of shorter wavelength and higher intensity can distinctly decrease the radiation-induced loss of Ge-doped fibres, especially at low temperatures. Another possibility to apply photo-bleaching by short wavelength is to regenerate fibres that are permanently installed in radiation environments. Modern undoped multi-mode (MM) step index (Si), Ge-doped MM graded index (Gi) and Ge-doped single-mode (SM) fibres that had been irradiated were submitted to bleaching light. In this article it is shown how loss reduction and necessary bleaching time depend on wavelength and intensity of the bleaching light, on fibre length (bleaching time) and on radiation dose. These results are promising for the regeneration of optical fibres in facilities where the fibres cannot be replaced easily by new ones. (A.C.)

Statistical data for the tensile properties of natural fibre composites

Directory of Open Access Journals (Sweden)

J.P. Torres

2017-06-01

Full Text Available This article features a large statistical database on the tensile properties of natural fibre reinforced composite laminates. The data presented here corresponds to a comprehensive experimental testing program of several composite systems including: different material constituents (epoxy and vinyl ester resins; flax, jute and carbon fibres, different fibre configurations (short-fibre mats, unidirectional, and plain, twill and satin woven fabrics and different fibre orientations (0°, 90°, and [0,90] angle plies. For each material, ~50 specimens were tested under uniaxial tensile loading. Here, we provide the complete set of stress–strain curves together with the statistical distributions of their calculated elastic modulus, strength and failure strain. The data is also provided as support material for the research article: “The mechanical properties of natural fibre composite laminates: A statistical study” [1].

Dual fuel mode operation in diesel engines using renewable fuels: Rubber seed oil and coir-pith producer gas

Energy Technology Data Exchange (ETDEWEB)

Ramadhas, A.S.; Jayaraj, S.; Muraleedharan, C. [Department of Mechanical Engineering, National Institute of Technology Calicut, Calicut-673601 (India)

2008-09-15

Partial combustion of biomass in the gasifier generates producer gas that can be used as supplementary or sole fuel for internal combustion engines. Dual fuel mode operation using coir-pith derived producer gas and rubber seed oil as pilot fuel was analyzed for various producer gas-air flow ratios and at different load conditions. The engine is experimentally optimized with respect to maximum pilot fuel savings in the dual fuel mode operation. The performance and emission characteristics of the dual fuel engine are compared with that of diesel engine at different load conditions. Specific energy consumption in the dual-fuel mode of operation with oil-coir-pith operation is found to be in the higher side at all load conditions. Exhaust emission was found to be higher in the case of dual fuel mode of operation as compared to neat diesel/oil operation. Engine performance characteristics are inferior in fully renewable fueled engine operation but it suitable for stationary engine application, particularly power generation. (author)

Effect of water absorption on mechanical properties of flax fibre reinforced composites

CSIR Research Space (South Africa)

Guduri, BBR

2007-01-01

Full Text Available Scutched and line flax fibres, with mean linear density of about 19.5 decitex, were utilized for this study. Mechanical properties of fibre and resin were measured for assessing their contribution in the composite matrix. Polypropylene (PP)/ short...

Preparation of super water absorption materials by radiation grafting of sodium acrylate onto coir dust for agriculture use

International Nuclear Information System (INIS)

Nguyen Trong Hoanh Phong; Nguyen Tan Man; Nguyen Tuong Ly Lan; Tran Thi Thuy; Le Van Toan; Le Huu Tu; Le Xuan Cuong; Pham Thi Sam; Le Hong En; Le Hai

2013-01-01

Preparation of super water absorption materials using coir dust and sodium acrylate has been carried out by radiation grafting techniques using gamma irradiator of Co-60 source, at Radiation technology Dept., Nuclear Research Institute. Effect of irradiation dose, coir dust content and NaOH concentration to the forming-gel yield has been studied. Results show the gel content achieved the highest value of 96%, at 15 kGy of irradiation dose, 25% coir dust content and 20% NaOH. The parameters affect to the swelling behavior of studied products have been investigated. The characteristics of product structure have been determined by FTIR and SEM. It is indicated that swelling degree of products increases in the increasing of immerging time but decreases with the increase of irradiation dose. In the other hands, the swelling behavior of studied products extremely depends on processing condition such as drying temperature and their particle size. It is seen that 50 o C and 200 µm are the optimal parameters of drying temperature and particle sizes of product. The efficiency of water retention of products in sandy and soil media has been determined, results show the amount of water has been remained higher than 40%, in case of sand and soil contain 0.7% PSHT and keeping in dry condition after 60 days. Meanwhile the amount of water almost equal to 0 after 20 days and 60 days for sand and soil respectively. Application of studied products for corn and coffee crops on sand and soil has been evaluated for positive results after 45 days without irrigation but their growing still stable. (author)

Intralobar fibres of the occipital lobe: a post mortem dissection study.

Science.gov (United States)

Vergani, Francesco; Mahmood, Sajedha; Morris, Cristopher M; Mitchell, Patrick; Forkel, Stephanie J

2014-07-01

The atlas by Heinrich Sachs (1892) provided an accurate description of the intralobar fibres of the occipital lobe, with a detailed representation of the short associative tracts connecting different parts of the lobe. Little attention has been paid to the work of Sachs since its publication. In this study, we present the results of the dissection of three hemispheres, performed according to the Klingler technique (1935). Our anatomical findings are then compared to the original description of the occipital fibres anatomy as detailed by Sachs. Three hemispheres were dissected according to Klingler's technique (1935). Specimens were fixed in 10% formalin and frozen at -15 °C for two weeks. After defreezing, dissection of the white matter fibres was performed with blunt dissectors. Coronal sections were obtained according to the cuts originally described by Sachs. In addition, medial to lateral and lateral to medial dissection of the white matter of the occipital lobe was also performed. A network of short association fibres was demonstrated in the occipital lobe, comprising intralobar association fibres and U-shaped fibres, which are connecting neighbouring gyri. Lateral to the ventricles, longitudinal fibres of the stratum sagittale were also identified that are arranged as external and internal layers. Fibres of the forceps major were also found to be in direct contact with the ventricular walls. We were able to replicate all tracts originally described by Sachs. In addition, a previously unrecognised tract, connecting the cuneus to the lingual gyrus, was identified. This tract corresponds to the "sledge runner", described in tractography studies. The occipital lobe shows a rich network of intralobar fibres, arranged around the ventricular wall. Good concordance was observed between the Klingler dissection technique and the histological preparations of Sachs. Copyright © 2014 Elsevier Ltd. All rights reserved.

Mechanical behaviour of fibre reinforced concrete using soft - drink can

Science.gov (United States)

Ilya, J.; Cheow Chea, C.

2017-11-01

This research was carried out to study the behaviour of concrete, specifically compressive and flexural strength, by incorporating recycled soft drink aluminium can as fibre reinforcement in the concrete. Another aim of the research is to determine the maximum proportion of fibres to be added in the concrete. By following standard mix design, Ordinary Portland Cement (OPC) concrete was made to have a target mean strength of 30 N/mm2 with not more than 30 mm of slump. Having the same workability, OPC concrete with 0%, 1% and 2% of soft drink can aluminium fibre was prepared based on weight of cement. The specimens were tested for compressive strength and flexural strength. Laboratory test results based on short term investigation reveals that the compressive strength and flexural strength of concrete containing fibre are higher than of normal OPC concrete. Among two volume fractions, concrete with 1% of soft drink can fibre have performed better result in compressive strength and flexural strength compared with 2% amount of soft drink can fibre. The optimum proportion of aluminium fibre to be added in the concrete as fibre reinforcement is 1% fibre content by weight of cement which gave all the positive response from all the tests conducted.

Porosity Assessment for Different Diameters of Coir Lignocellulosic Fibers

Science.gov (United States)

da Luz, Fernanda Santos; Paciornik, Sidnei; Monteiro, Sergio Neves; da Silva, Luiz Carlos; Tommasini, Flávio James; Candido, Verônica Scarpini

2017-10-01

The application of natural lignocellulosic fibers (LCFs) in engineering composites has increased interest in their properties and structural characteristics. In particular, the inherent porosity of an LCF markedly affects its density and the adhesion to polymer matrices. For the first time, both open and closed porosities of a natural LCF, for different diameter ranges, were assessed. Fibers extracted from the mesocarp of the coconut fruit were investigated by nondestructive methods of density measurements and x-ray microtomography (microCT). It was found that, for all diameter ranges, the closed porosity is significantly higher than the open porosity. The total porosity increases with diameter to around 60% for coir fibers with more than 503 μm in diameter. The amount and characteristics of these open and closed porosities were revealed by t test and Weibull statistics as well as by microCT.

Scintillating optical fibres and the detection of very short lived particles

International Nuclear Information System (INIS)

Fisher, C.M.

1985-01-01

The application of scintillating fiber optics to the problem of heavy flavour particle detection in both fixed target and collider experiments is reviewed. Brief specifications for both fibres and read-out systems are given. (orig.)

Experimental investigation on an entrained flow type biomass gasification system using coconut coir dust as powdery biomass feedstock.

Science.gov (United States)

Senapati, P K; Behera, S

2012-08-01

Based on an entrained flow concept, a prototype atmospheric gasification system has been designed and developed in the laboratory for gasification of powdery biomass feedstock such as rice husks, coconut coir dust, saw dust etc. The reactor was developed by adopting L/D (height to diameter) ratio of 10, residence time of about 2s and a turn down ratio (TDR) of 1.5. The experimental investigation was carried out using coconut coir dust as biomass feedstock with a mean operating feed rate of 40 kg/h The effects of equivalence ratio in the range of 0.21-0.3, steam feed at a fixed flow rate of 12 kg/h, preheat on reactor temperature, product gas yield and tar content were investigated. The gasifier could able to attain high temperatures in the range of 976-1100 °C with gas lower heating value (LHV) and peak cold gas efficiency (CGE) of 7.86 MJ/Nm3 and 87.6% respectively. Copyright © 2012 Elsevier Ltd. All rights reserved.

Loss of protohaem IX farnesyltransferase in mature dentate granule cells impairs short-term facilitation at mossy fibre to CA3 pyramidal cell synapses.

Science.gov (United States)

Booker, Sam A; Campbell, Graham R; Mysiak, Karolina S; Brophy, Peter J; Kind, Peter C; Mahad, Don J; Wyllie, David J A

2017-03-15

Neurodegenerative disorders can exhibit dysfunctional mitochondrial respiratory chain complex IV activity. Conditional deletion of cytochrome c oxidase, the terminal enzyme in the respiratory electron transport chain of mitochondria, from hippocampal dentate granule cells in mice does not affect low-frequency dentate to CA3 glutamatergic synaptic transmission. High-frequency dentate to CA3 glutamatergic synaptic transmission and feedforward inhibition are significantly attenuated in cytochrome c oxidase-deficient mice. Intact presynaptic mitochondrial function is critical for the short-term dynamics of mossy fibre to CA3 synaptic function. Neurodegenerative disorders are characterized by peripheral and central symptoms including cognitive impairments which have been associated with reduced mitochondrial function, in particular mitochondrial respiratory chain complex IV or cytochrome c oxidase activity. In the present study we conditionally removed a key component of complex IV, protohaem IX farnesyltransferase encoded by the COX10 gene, in granule cells of the adult dentate gyrus. Utilizing whole-cell patch-clamp recordings from morphologically identified CA3 pyramidal cells from control and complex IV-deficient mice, we found that reduced mitochondrial function did not result in overt deficits in basal glutamatergic synaptic transmission at the mossy-fibre synapse because the amplitude, input-output relationship and 50 ms paired-pulse facilitation were unchanged following COX10 removal from dentate granule cells. However, trains of stimuli given at high frequency (> 20 Hz) resulted in dramatic reductions in short-term facilitation and, at the highest frequencies (> 50 Hz), also reduced paired-pulse facilitation, suggesting a requirement for adequate mitochondrial function to maintain glutamate release during physiologically relevant activity patterns. Interestingly, local inhibition was reduced, suggesting the effect observed was not restricted to synapses

Latest developments in silica fibre luminescence dosimetry

Energy Technology Data Exchange (ETDEWEB)

Bradley, D. A.; Abdul S, S. F.; Jafari, S. M.; Alanazi, A. [University of Surrey, Department of Physics, GU2 7XH Guildford, Surrey (United Kingdom); Amouzad M, G. [University of Malaya, Faculty of Engineering, Department of Electrical Engineering, Integrated Lightwave Research Group, 50603 Kuala Lumpur (Malaysia); Addul R, H. A.; Mizanur R, A. K. M.; Zubair, H. T.; Begum, M.; Yusoff, Z.; Omar, N. Y. M. [Multimedia University, Faculty of Engineering, 2010 Cyberjaya, Selangor (Malaysia); Maah, M. J. [University of Malaya, Department of Chemistry, 50603 Kuala Lumpur (Malaysia); Collin, S. [National Physical Laboratory, Hampton Road, Teddington, TW11 OLW Middlesex (United Kingdom); Mat-Sharif, K. A.; Muhd-Yassin, S. Z.; Zulkifli, M. I., E-mail: d.a.bradley@surrey.ac.uk [Telekom Malaysia Research and Development Sdn Bhd., 63000 Cyberjaya, Selangor (Malaysia)

2015-10-15

Full text: Using tailor made sub-mm diameter doped-silica fibres, we are carrying out luminescence dosimetry studies for a range of situations, including thermoluminescence (Tl)investigations on a liquid alpha source formed of {sup 223}RaCl (the basis of the Bayer Health care product Xofigo), the Tl response to a 62 MeV proton source and Tl response to irradiation from an {sup 241}Am-Be neutron source. In regard to the former, in accord with the intrinsic high linear energy transfer (Let) and short path length (<100 um) of the α-particles in calcified tissue, the product is in part intended as a bone-seeking radionuclide for treatment of metastatic cancer, offering high specificity and efficacy. The Tl yield of Ge-doped SiO{sub 2} fibres has been investigated including for photonic crystal fibre un collapsed, flat fibres and single mode fibres, these systems offering many advantages over conventional passive dosimetry types. In particular, one can mention comparable and even superior sensitivity, an effective atomic number Z{sub eff} of the silica dosimetric material close to that of bone, and the glassy nature of the fibres offering the additional advantage of being able to place such dosimeters directly into liquid environments. Finally we review the use of our tailor made fibres for on-line radioluminescence measurements of radiotherapy beams. The outcome from these various lines of research is expected to inform development of doped fiber radiation dosimeters of versatile utility, ranging from clinical applications through to industrial studies and environmental evaluations. (Author)

Mechanical properties of kenaf bast and core fibre reinforced unsaturated polyester composites

Energy Technology Data Exchange (ETDEWEB)

Ishak, M R; Leman, Z; Sapuan, S M [Department of Mechanical and Manufacturing Engineering, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Edeerozey, A M M; Othman, I S, E-mail: zleman@eng.upm.edu.my [Faculty of Manufacturing Engineering, Universiti Teknikal Malaysia Melaka, 76109 Durian Tunggal, Melaka (Malaysia)

2010-05-15

Kenaf fibre has high potential to be used for composite reinforcement in biocomposite material. It is made up of an inner woody core and an outer fibrous bark surrounding the core. The aim of this study was to compare the mechanical properties of short kenaf bast and core fibre reinforced unsaturated polyester composites with varying fibre weight fraction i.e. 0%, 5%, 10%, 20%, 30% and 40%. The compression moulding technique was used to prepare the composite specimens for tensile, flexural and impact tests in accordance to the ASTM D5083, ASTM D790 and ASTM D256 respectively. The overall results showed that the composites reinforced with kenaf bast fibre had higher mechanical properties than kenaf core fibre composites. The results also showed that the optimum fibre content for achieving highest tensile strength for both bast and core fibre composites was 20%wt. It was also observed that the elongation at break for both composites decreased as the fibre content increased. For the flexural strength, the optimum fibre content for both composites was 10%wt while for impact strength, it was at 10%wt and 5%wt for bast and core fibre composites respectively.

Mechanical properties of kenaf bast and core fibre reinforced unsaturated polyester composites

International Nuclear Information System (INIS)

Ishak, M R; Leman, Z; Sapuan, S M; Edeerozey, A M M; Othman, I S

2010-01-01

Kenaf fibre has high potential to be used for composite reinforcement in biocomposite material. It is made up of an inner woody core and an outer fibrous bark surrounding the core. The aim of this study was to compare the mechanical properties of short kenaf bast and core fibre reinforced unsaturated polyester composites with varying fibre weight fraction i.e. 0%, 5%, 10%, 20%, 30% and 40%. The compression moulding technique was used to prepare the composite specimens for tensile, flexural and impact tests in accordance to the ASTM D5083, ASTM D790 and ASTM D256 respectively. The overall results showed that the composites reinforced with kenaf bast fibre had higher mechanical properties than kenaf core fibre composites. The results also showed that the optimum fibre content for achieving highest tensile strength for both bast and core fibre composites was 20%wt. It was also observed that the elongation at break for both composites decreased as the fibre content increased. For the flexural strength, the optimum fibre content for both composites was 10%wt while for impact strength, it was at 10%wt and 5%wt for bast and core fibre composites respectively.

Analysis of damage processes in short glass fibre reinforced polyamide under mechanical loading by X-ray refractometry, fracture mechanics and fractography; Analyse der Schaedigungsprozesse in einem kurzglasfaserverstaerkten Polyamid unter mechanischer Belastung mittels Roentgenrefraktometrie, Bruchmechanik und Fraktografie

Energy Technology Data Exchange (ETDEWEB)

Guenzel, Stephan

2013-04-01

This thesis presents an analysis of the damage behaviour in a short glass fibre reinforced polyamide. The micro cracking is investigated by X-ray refraction technique under various, mechanical in-service loadings. In this context, potentials and limits of X-ray refraction analysis for short glass fibre reinforced polyamides are compiled. In particular the influence of fibre orientation and the influence of damage mechanisms are examined according to the X-ray refraction analysis and its interpretation. The method offers a quantitative and phenomenological based characterisation of micro crack damage. For the investigated material micro crack damage emerges as fibre matrix debonding and matrix micro cracking. The state of damage correlates with a nonlinear strain portion in a linear manner and depends on the kind of loading. Absorption of moisture in the material may influence significantly the micro crack damage behaviour. Damage of micro cracking appears preferentially under tension. The macro damage due to propagation of a single crack is characterised in an automated test setup, considering the fibre orientation and content of moisture. Based on the findings an empirical assessment approach is developed. The investigations of the micro and macro damage behaviour are accompanied by fractography, in order to support the model assumptions according to damage and fracture mechanisms.

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...

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

Pó de coco como substrato para produção de mudas de tomateiro Coconut coir fiber as a potting media for tomato seedling production

Directory of Open Access Journals (Sweden)

Elineide B. Silveira

2002-06-01

, quatro isolados de Pseudomonas fluorescentes, cinco isolados de Bacillus spp. e a mistura dos isolados Trichoderma + Pseudomonas fluorescentes + Bacillus. As suspensões foram adicionadas dois dias antes do plantio, na concentração de 0,52 A e 5 x 10(6 conídios/mL para bactérias e fungos, respectivamente. O incremento da população microbiana dos substratos não promoveu o crescimento das plântulas de tomateiro. Conclui-se que a utilização de pó de coco em mistura com outros substratos, principalmente com o PlantmaxÒ, é viável barateando o custo de produção de mudas de tomateiro.The production of seedlings is very important in the horticultural transplant industry and depends on the substrate utilization. The use of coconut coir fiber alone was evaluated or in combination with other potting media to produce transplants of tomato cv. 'Santa Adélia'. Cococnut coir fiber potting media PlantmaxÒ and earthworm castings were tested separated and in volumetric combinations: PlantmaxÒ + cocunut coir fiber, worm cast + cocunut coir fiber, PlantmaxÒ + earthworm casting and PlantmaxÒ + coconut coir fiber + earthworm casting, evaluating the variables germination 10 days after planting, leaf number, plant height, shoot fresh matter and shoot dry matter at 25 days after planting. The mixed substrates were superior to those from single components mainly PlantmaxÒ + coconut coir fiber + earthworm casting. The indigenous microbial population in each one of the three substrates was quantified in relation to the variables total bacteria, total fungi, fluorescent Pseudomonas spp., Bacillus and Trichoderma. In coconut coir fiber and earthworm casting the bacterial population surpassed the fungal. Earthworm casting and coconut coir fiber showed respectively higher population of total bacteria (240.56 x 10(4 UFC/g of dry substrate and total fungi (86.98 x 10(4 UFC/g of dry substrate. Fluorescent Pseudomonas spp. were detected in earthworm casting (1.65 x 10(4 UFC/g of dry

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 ...

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.

3D modelling of the flow of self-compacting concrete with or without steel fibres. Part II: L-box test and the assessment of fibre reorientation during the flow

Science.gov (United States)

Deeb, R.; Kulasegaram, S.; Karihaloo, B. L.

2014-12-01

The three-dimensional Lagrangian particle-based smooth particle hydrodynamics method described in Part I of this two-part paper is used to simulate the flow of self-compacting concrete (SCC) with and without steel fibres in the L-box configuration. As in Part I, the simulation of the SCC mixes without fibres emphasises the distribution of large aggregate particles of different sizes throughout the flow, whereas the simulation of high strength SCC mixes which contain steel fibres is focused on the distribution of fibres and their orientation during the flow. The capabilities of this methodology are validated by comparing the simulation results with the L-box test carried out in the laboratory. A simple method is developed to assess the reorientation and distribution of short steel fibres in self-compacting concrete mixes during the flow. The reorientation of the fibres during the flow is used to estimate the fibre orientation factor (FOF) in a cross section perpendicular to the principal direction of flow. This estimation procedure involves the number of fibres cut by the section and their inclination to the cutting plane. This is useful to determine the FOF in practical image analysis on cut sections.

Impact of cereal fibre on glucose-regulating factors

DEFF Research Database (Denmark)

Weickert, M O; Mohlig, M; Koebnick, C

2005-01-01

postprandial glucose response on the following day subsequent to ingestion of a control meal (AUC(C-C) 4,140+/-401, AUC(C-WF) 2,850+/-331 [p=0.007], AUC(C-OF) 2,830+/-277 [p=0.011]), with no difference in maximal concentration and T(max) of glucose responses. No differences in insulin responses were observed......AIMS/HYPOTHESIS: Insoluble dietary fibre intake is associated, by unknown mechanisms, with a reduced risk of type 2 diabetes. We investigated whether a short-term dietary intervention with purified insoluble fibres influences acute and delayed responses of glucose, insulin, glucose...

Study of pyrolysed acid and based treated coconut coir as green photocatalyst substrate

Science.gov (United States)

Asim, Nilofar; Emdadi, Zeynab; Abdullah, N. A.; Mohammad, Masita; Badiei, Marzieh; Sopian, Kamaruzzaman

2017-12-01

This study investigates the possible contribution to sustainable development by utilizing agriculture waste materials to prepare a substrate for photo-catalysis application. The photocatalytic performance of impregnated TiO2 on acid and base- treated coconut coir (CC) and their pyrolysed form have been studied. The photocatalytic performance of impregnated TiO2 on acid treated CC improved compared to bare TiO2. However, the pyrolysed samples showed higher thermal stability and porosity compared to only treated CC, their catalytic performance was decreased. It seems that impregnated TiO2 undergo interaction with treated CC during pyrolysis. More investigations to reveal exact reason of this behavior is in progress.

A planar model study of creep in metal matrix composites with misaligned short fibres

DEFF Research Database (Denmark)

Sørensen, N.J.

1993-01-01

The effect of fibre misalignment on the creep behaviour of metal matrix composites is modelled, including hardening behaviour (stage 1), dynamic recovery and steady state creep (stage 2) of the matrix material, using an internal variable constitutive model for the creep behaviour of the metal...... matrix. Numerical plane strain results in terms of average properties and detailed local deformation behaviour up to large strains are needed to show effects of fibre misalignment on the development of inelastic strains and the resulting over-all creep resistance of the material. The creep resistance...

Production process for high density high performance binderless boards from whole coconut husk

NARCIS (Netherlands)

Dam, van J.E.G.; Oever, van den M.J.A.; Keijsers, E.R.P.

2004-01-01

Coconuts are typically growing in coastal areas of tropical countries. The husk is abundantly available as cheap residue from coconut production in many areas, which is known to yield the coarse coir fibre. In this project a simple and efficient technology has been developed to produce high

Preparation of Reducing Sugar Hydrolyzed from High-Lignin Coconut Coir Dust Pretreated by the Recycled Ionic Liquid [mmim][dmp] and Combination with Alkaline

Directory of Open Access Journals (Sweden)

Hanny Frans Sangian

2015-03-01

Full Text Available This study aims to produce reducing sugar hydrolyzed from substrate, coconut coir dust pretreated by recycled ionic liquid and its combination with alkaline. The 1H NMR and FTIR were performed to ver-ify the synthesized ionic liquid methylmethylimidazolium dimethyl phosphate ([mmim][dmp]. The structure of pretreated substrates was analyzed by XRD measurement. The used ionic liquid was recy-cled twice to re-employ for substrate pretreatment. The treated- and untreated-coconut coir dust were hydrolyzed into sugars using pure cellulase. The reaction, which called an enzymatic hydrolysis, was conducted at 60 °C, pH 3, for 48 h. The yields of sugar hydrolyzed from fresh IL-pretreated, 1R*IL-pretreated and 2R*IL-pretreated substrates were of 0.19, 0.15 and 0.15 g sugar / g cellu-lose+hemicellulose, respectively. Pretreatment with NaOH or the combination of NaOH+IL resulted in yields of reducing sugars of 0.25, 0.28 g/g, respectively. When alkaline combined with the recycled ionic liquids, NaOH+1R*IL, NaOH+2R*IL in the pretreatment, the yields of sugar were relatively similar to those obtained using alkaline followed by fresh ionic liquid. If the mixture enzymes, cellu-lase+xylanase, used to liberate sugars from fresh IL-pretreated, or recycled IL-pretreated substrates, the amount of sugar (concentration or yield increased slightly compared to that employing a single cel-lulase. These findings showed that recycled IL pretreatment of the high-lignin lignocellulose, coconut coir dust, is a new prospect for the economical manufacture of fermentable sugars and biofuel in the coming years. © 2015 BCREC UNDIP. All rights reservedReceived: 1st July 2014; Revised: 5th September 2014; Accepted: 5th September 2014 How to Cite: Sangian, H.F., Kristian, J., Rahma, S., Dewi, H., Puspasari, D., Agnesty, S., Gunawan, S., Widjaja, A. (2015. Preparation of Reducing Sugar Hydrolyzed from High-Lignin Coconut Coir Dust Pretreated by the Recycled Ionic Liquid [mmim

3D modelling of the flow of self-compacting concrete with or without steel fibres. Part I: slump flow test

Science.gov (United States)

Deeb, R.; Kulasegaram, S.; Karihaloo, B. L.

2014-12-01

In part I of this two-part paper, a three-dimensional Lagrangian smooth particle hydrodynamics method has been used to model the flow of self-compacting concrete (SCC) with or without short steel fibres in the slump cone test. The constitutive behaviour of this non-Newtonian viscous fluid is described by a Bingham-type model. The 3D simulation of SCC without fibres is focused on the distribution of large aggregates (larger than or equal to 8 mm) during the flow. The simulation of self-compacting high- and ultra-high- performance concrete containing short steel fibres is focused on the distribution of fibres and their orientation during the flow. The simulation results show that the fibres and/or heavier aggregates do not precipitate but remain homogeneously distributed in the mix throughout the flow.

Effects of fibre content on mechanical properties and fracture ...

Indian Academy of Sciences (India)

Administrator

cost. The most important factors that affect the short fibres reinforcement are ... made with conventional techniques, including single or twin screw extruding (Li et al 2005), wet ball-milling mixing (Song et al 2002) and high-speed mechanical.

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.

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

In vitro acellular dissolution of mineral fibres: A comparative study.

Science.gov (United States)

Gualtieri, Alessandro F; Pollastri, Simone; Bursi Gandolfi, Nicola; Gualtieri, Magdalena Lassinantti

2018-05-04

The study of the mechanisms by which mineral fibres promote adverse effects in both animals and humans is a hot topic of multidisciplinary research with many aspects that still need to be elucidated. Besides length and diameter, a key parameter that determines the toxicity/pathogenicity of a fibre is biopersistence, one component of which is biodurability. In this paper, biodurability of mineral fibres of social and economic importance (chrysotile, amphibole asbestos and fibrous erionite) has been determined for the first time in a systematic comparative way from in vitro acellular dissolution experiments. Dissolution was possible using the Gamble solution as simulated lung fluid (pH = 4 and at body temperature) so to reproduce the macrophage phagolysosome environment. The investigated mineral fibres display very different dissolution rates. For a 0.25 μm thick fibre, the calculated dissolution time of chrysotile is in the range 94-177 days, very short if compared to that of amphibole fibres (49-245 years), and fibrous erionite (181 years). Diffraction and SEM data on the dissolution products evidence that chrysotile rapidly undergoes amorphization with the formation of a nanophasic silica-rich fibrous metastable pseudomorph as first dissolution step whereas amphibole asbestos and fibrous erionite show minor signs of dissolution even after 9-12 months.

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

Nonlocal plasticity effects on fibre debonding in a whisker-reinforced metal

DEFF Research Database (Denmark)

Niordson, Christian Frithiof; Tvergaard, Viggo

2002-01-01

Numerical cell-model analyses for the matrix-fibre debonding in a metal matrix composite are used to study the effect of a characteristic material length in the plasticity description of the matrix material deformations. Characteristic material lengths are already present in the model problem...... in the problem. The nonlocal plasticity effect tends to increase the stress level at a given overall strain, which clearly tends to promote the onset of debonding......., in the form of fibre sizes and the length associated with the debonding process, so the nonlocal plasticity model brings in an additional material length. The analyses for metal reinforced by aligned short fibres are used to obtain an understanding of the interaction of the different length scales...

Cavitation instabilities between fibres in a metal matrix composite

DEFF Research Database (Denmark)

Tvergaard, Viggo

2016-01-01

induced by bonding to the ceramics that only show elastic deformation. In an MMC the stress state in the metal matrix is highly non-uniform, varying between regions where shear stresses are dominant and regions where hydrostatic tension is strong. An Al–SiC whisker composite with a periodic pattern......Short fibre reinforced metal matrix composites (MMC) are studied here to investigate the possibility that a cavitation instability can develop in the metal matrix. The high stress levels needed for a cavitation instability may occur in metal–ceramic systems due to the constraint on plastic flow...... of transversely staggered fibres is here modelled by using an axisymmetric cell model analysis. First the critical stress level is determined for a cavitation instability in an infinite solid made of the Al matrix material. By studying composites with different distributions and aspect ratios of the fibres...

Factors optimization to improve the tensile and flexural properties of short fibre non-woven hedgehog chestnuts spines reinforced polyester composites

OpenAIRE

Ribeiro, J.E.; Rocha, João; Queijo, Luís

2016-01-01

Over the last decade has been observed an increased interest in the use of natural fibers instead of synthetic fibres (i.e. glass, carbon or kevlar fibres). The natural fibre composites (NFC) have important advantages like their fibers are a renewable resource, for which production requires little energy, involves CO2 absorption, whilst returning oxygen to the environment and can be produced at lower cost than synthetic fibre [1]. However, the NFC have also some limitations, na...

New insulating particleboards from durian peel and coconut coir

Energy Technology Data Exchange (ETDEWEB)

Khedari, J.; Charoenvai, S.; Hirunlabh, J. [King Mongkut' s Univ. of Technology Thonburi, Bangkok (Thailand). Building Scientific Research Center

2002-03-01

The development of new particleboards from tropical fruit peels with low thermal conductivity as a component of construction panels for energy conservation of building is the main purpose of this study. Durian (Durio zibethinus) peels and coconut (Cocos nucifera) coir fibers were used as the raw material to manufacture particleboards. Two main parameters were investigated namely binder types, (UF 12%, PF 6% and IC 3%) and board density. In general, the effect of adhesive type on the properties of boards was not obvious whereas that of the density was more significant on most properties of boards. Experimental investigation indicated that the mechanical strength of all boards such as modulus of rupture and modulus of elasticity increased with increasing board density, but it is still rather low. However, this decreased the dimensional stability, measured in term of thickness swelling, and thermal conductivity as well. Finally, as the raw materials are agriculture waste, manufacturing particleboards is therefore an economic and interesting option. Such natural particleboards with a low thermal conductivity could be utilized for specific applications as in insulating ceiling and walls.(author)

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.

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...

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.

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.

The dry-heat loss effect of melt-spun phase change material fibres.

Science.gov (United States)

Tjønnås, Maria Suong; Færevik, Hilde; Sandsund, Mariann; Reinertsen, Randi E

2015-01-01

Phase change materials (PCM) have the ability to store latent heat when they change phases, a property that gives clothing that incorporates PCM its cooling effect. This study investigated the effect of dry-heat loss (cooling) of a novel melt-spun PCM fibre on the basis of the area covered, mass, the latent heat of fusion and melting temperature, compared to a known PCM clothing product. PCM fibres with melting temperatures of 28.4 and 32.0°C and PCM packs with melting temperatures of 28.0 and 32.0°C were studied. The results showed that the PCM fibres had a larger initial peak cooling effect than that of the PCM packs. The duration of the cooling effect of PCM fibres was primarily dependent on the PCM mass and the latent heat of fusion capacity, and secondly on the covered area and melting temperature of the PCM. This study investigates the cooling effect of PCM fibres on a thermal manikin. The PCM fibres had a high but short-lasting cooling effect. This study contributes to the knowledge of how the body's temperature regulation may be affected by the cooling properties of clothing that incorporates PCM.

Growth and Yield of Rice Plant by the Applications of River Sand, Coconut and Banana Coir in Ustic Endoaquert

Directory of Open Access Journals (Sweden)

Nurdin

2013-03-01

Full Text Available The research aimed to study effect the application of river sand (RS, coconut coir (CC, and banana coir (BC on growth and yield of rice (Oryza sativa L. in Ustic Endoaquert. The research was carried out in a green house using 3 × 3 × 3 factorial design. The RS factor consists of three treatment levels which were 0% RS, 25% RS, and 50% RS. Meanwhile, the CC and BC consist of three treatment levels, where each level were 0 Mg ha-1, 10 Mg ha-1 and 20 Mg ha-1. The results showed that RS, CC and BC applications did not have significant effect on plant height. On the other hand, all ameliorant applications had significantly increase leaf length and the highest percentage increasing was in BC (13.49%. The leaf numbers and tiller numbers had relatively similar pattern, except BC that had significantly increased leaf numbers by 77.69% and amount of tiller numbers by 49.45%. Furthermore, for yield components, RS, CC and BC applications had significant increased panicle numbers by 37.76%. It was only RS and BC that increased panicle lenght and the best increasing of 26.82% on RS. Meanwhile, the BC application only increased the rice grain numbers.

Static and cyclic performance of cementitious composites reinforced with glass-fibres

International Nuclear Information System (INIS)

Arabi, N.

2018-01-01

This paper concerns an experimental study of the influence of short glass-fibres randomly oriented of a reinforced cement-based composite on the mechanical behaviour. The matrix material parameters used are: cement/sand ratio and water/cement ratio fixed at 0.5; the glass-fibre content (0%, 0.5%, 1.0%, 1.5%, 2% and 2.5%) and fibre lengths (3, 6 and 12 mm). Composites mechanical characterisation under static behaviour at flexural and compression tests, shows that the reinforcement effect is beneficial only in flexural case. A synergy (matrix-reinforcement) was observed when fibre length of 12 mm is used with application rate of 2% in flexural. The fatigue behaviour determined by Wöhler plots (stress-number of cycles to rupture), derived from experimental results; showed a large results dispersion which is attributed to many causes initiating this damage. The cyclic tests illustrate brittle character of these materials; even with low-amplitude cycles of loading no adaptation of these materials can be reported. [es

Adsorption characteristics of cadmium(II) onto functionalized poly(hydroxyethylmethacrylate)-grafted coconut coir pith.

Science.gov (United States)

Anirudhan, Thayyath Sreenivasan; Divya, Lekshmi; Rijith, Sreenivasan

2010-07-01

This study explored the feasibility of utilizing a novel adsorbent, poly(hydroxyethylmethacrylate)-grafted coconut coir pith with carboxyl functionality (PGCP-COOH) for the removal of cadmium(II) from water and wastewater. Maximum removal of 99.9% was observed for an initial concentration of 25 mg/L at pH 6.0 and adsorbent dose of 2.0 g/L. The first-order reversible kinetic model and Langmuir isotherm model were resulted in high correlation coefficients and described well the adsorption of Cd(II) onto PGCP-COOH. The complete removal of 22.4 mg/L Cd(II) from fertilizer industry wastewater was achieved by 2.0 g/L PGCP-COOH. The reusability of the PGCP-COOH for several cycles was demonstrated using 0.1 M HCl solution.

Hybrid fibre-reinforced concrete under repeated loading

International Nuclear Information System (INIS)

Komlos, K.; Babal, B.; Nuernbergerova, T.

1995-01-01

Fibre-reinforced concrete containing several volume fractions in different ratios of two types of fibre - polypropylene and steel - were tested under repeated loading. The mechanical properties of specimens - cubes 150mm x 150mm x 150mm (for compressive strength), prisms 100mm x 100mm x 400mm (for flexural strength) and short cylinders 150mm long and 60mm in diameter (for impact strength) - have been experimentally investigated before and after cyclic loading after a curing time of 28 days.Mix proportions were designed according to DIN 1045 with maximum aggregate size 8mm and grading curve B8. Portland cement PC 40 in the amount of 450kgm -3 was applied and the water-to-cement ratio was 0.55. The workability of mixes was measured by the Vebe method and regulated by the plasticizing admixture Ligoplast Na. The maximum hybrid fibre volume fraction (polypropylene+steel) was 1.0%. The dynamic forces generated in a Schenck testing machine with a frequency of 16Hz had a sinusoidal waveform varying between 0.7 and 0.1 of the static mechanical characteristics. The number of cycles in all tests was 10 5 . The residual MOR in the static four-point bending test and working force-deflection diagram were also obtained. The impact properties after repeated loading in compression were tested by means of the falling-weight test. Relationships between the composition of fibre composites with different amounts of polypropylene (0.2, 0.3 and 0.5vol.%) and steel fibre content (0.5, 0.7 and 0.8vol.%) were obtained and the technological properties of the mixes as well. (orig.)

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...

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)

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.

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)

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...

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

Effect of molarity in geo polymer earth brick reinforced with fibrous coir wastes using sandy soil and quarry dust as fine aggregate. (Case study

Directory of Open Access Journals (Sweden)

P. Palanisamy

2018-06-01

Full Text Available The studies are mainly carried out on strength development for various grades of geo-polymer mortar with varying molarity (M for producing geo-polymer earth brick (GPEB. The studies are focused on use of more sandy soil sieved from the raw earth available at site and quarry dust on replaced with river sand for making the un-burnt brick. The brick is reinforced with fibrous coir waste to increase shear strength and further pressed by hand compaction. Geo-polymer mortar is based on an inorganic alumina silicate binder system and it has more advantages of quick strength gain, negligence of water curing, best mechanical properties, eco-friendly, sustainable and alternate to ordinary Portland cement (OPC based mortar. Fly Ash (FA, Ground Granulated Blast-furnace Slag (GGBS, sandy soil sieved from earth and Quarry Dust (QD are mixed with alkaline solution in different molarities 6 M, 8 M and 10 M to prepare specimens. Specimens are tested against workability, compressive strength, and water absorption test, rate of water absorption, abraded test and also fiber content of the brick. The research found that the brick is made by FA & GGBS as binders and soil & quarry dust as fine aggregate in ratio of 0.5:0.5:1.75:0.25 with fibrous coir waste 1% and alkaline solution 10 M for preparing mortar to produce, excellent compressive strength, low water absorption, low rate of absorption, good abrasive resistance etc., The new brick is placed an alternate to compressed stabilized earth block, cement block and traditional burnt brick. Keywords: Fiber reinforced geo-polymer earth brick, Geo-polymer mortar using sandy soil and quarry dust as fine-aggregate, Nature fibrous coir wastes, Un-burnt brick, Alternate to compressed stabilized earth block

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...

Novel technique for solar power illumination using plastic optical fibres

Science.gov (United States)

Munisami, J.; Kalymnios, D.

2008-09-01

Plastic Optical Fibres (POF) were developed almost 3 decades ago. They are mainly used for short haul data communications (up to 1 km with data rates up to 1 Gbps). Over the years, POF has found applications in many other areas including solar energy transport for illumination. In such an application, light is collected from the sun and is directed into a space which needs to be illuminated. The use of fibres and more specifically POF, in daylighting systems, started only a few years ago. Several approaches have been investigated and we have seen the development of a few commercial products. The market however, has not really taken off for these technologies simply because of their enormous price tags. It is important to note that the use of POF in these designs has been limited to the function of POF as the transmission medium only. We propose a novel solar illumination technique using POF as both the light collecting/concentrating mechanism and the transmission medium. By modifying the structure of the fibre, solar light can be directed into the fibre by using an analogous process to fibre side emission but, in the reverse. We shall report on the solar light capturing efficiency of POF as modified by several types of external imperfections introduced onto the fibre. One major advantage of our proposed approach lies in the fact that we aim to eliminate at least one of the two axes of sun tracking that is currently used in existing solar illumination systems.

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.

Fractionation of high Kappa number kraft pulps of the South African softwoods and sulfonating of coarse fibre enriched fraction for production of sack paper

CSIR Research Space (South Africa)

Johakimu, Jonas K

2011-03-01

Full Text Available properties except tear strength: Tensile index (54%), TEA index (104%), Burst index (65%) and sheet density (23%). A tear index decrease (30%) could be attrib- uted to a high proportion of short and fine fibres in the accept stream. The reject stream... gave pulp samples with inferior strength properties with exception of tear strength. This may be due to high proportion of coarse fibres which have limited fibre collapsibility. Poor fibre collapsibility leads to a limited fibre bond- ing ability...

Fibre autoradiography of repair and replication in DNA from single cells: the effect of DNA synthesis inhibitors

Energy Technology Data Exchange (ETDEWEB)

Ockey, C.H.

1982-04-01

DNA fibre autoradiography, after incorporation of high specific activity /sup 3/H-thymidine and /sup 3/H-deoxycytidine, has been used to investigate repair in DNA fibres from single cells following UV, or methyl-methane sulphonate (MMS) treatment. Asynchronously growing human fibroblasts, leucocytes, and HeLa cells at different phases of the cell cycle have been investigated. Isotope incorporation in repair could be differentiated from that involved in replication by the distribution and density of silver grains along the DNA fibres. Grain distribution due to repair was continuous over long stretches of the fibres and was at a low density, occasionally interspersed with short slightly denser segments. Replication labelling on the other hand, was dense and usually in short tandem segments. Repair labelling was of a similar overall density in fibres from a single cell, but differed in intensity from cell to cell. In mutagen treated Go (leucocytes) of G/sub 1/ (HeLa cells), repair labelling was not increased by the presence of the DNA inhibitors, hydroxyurea (HU) or 5-fluorodeoxyuridine (FUdR). Repair was not detectable in S cells however without the use of these inhibitors to reduce endogenous nucleoside production. FUdR enhanced the repair labelling in S cells only slightly, while HU increased it beyond that observed in UV irradiated, HU treated, G/sub 1/ cells. The intensity of repair labelling in fibres from mutagen treated S cells appears to be proportional to the degree of reduction of DNA chain elongation in replicons.

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.

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 ...

Mercury(II) removal from aqueous solutions and wastewaters using a novel cation exchanger derived from coconut coir pith and its recovery

International Nuclear Information System (INIS)

Anirudhan, T.S.; Divya, L.; Ramachandran, M.

2008-01-01

A new adsorbent (PGCP-COOH) having carboxylate functional group at the chain end was synthesized by grafting poly(hydroxyethylmethacrylate) onto coconut coir pith, CP (a coir industry-based lignocellulosic residue), using potassium peroxydisulphate as an initiator and in the presence of N,N'-methylenebisacrylamide as a cross-linking agent. The adsorbent was characterized with the help of infrared spectroscopy, powder X-ray diffraction, scanning electron microscopy, and potentiometric titrations. The ability of PGCP-COOH to remove Hg(II) from aqueous solutions was assessed using batch adsorption technique under kinetic and equilibrium conditions. Adsorbent exhibits very high adsorption potential for Hg(II) and more than 99.0% removal was achieved in the pH range 5.5-8.0. Adsorption process was found to follow first-order-reversible kinetics. An increase of ionic strength of the medium caused a decrease in metal removal, indicating the occurrence of outer-sphere surface complex mechanism. The equilibrium data were fitted well by the Freundlich isotherm model (R 2 = 0.99; χ 2 1.81). The removal efficiency was tested using chlor-alkali industry wastewater. Adsorption isotherm experiments were also conducted for comparison using a commercial carboxylate-functionalized ion exchanger, Ceralite IRC-50. Regeneration experiments were tried for four cycles and results indicate a capacity loss of <9.0%

Mercury(II) removal from aqueous solutions and wastewaters using a novel cation exchanger derived from coconut coir pith and its recovery.

Science.gov (United States)

Anirudhan, T S; Divya, L; Ramachandran, M

2008-09-15

A new adsorbent (PGCP-COOH) having carboxylate functional group at the chain end was synthesized by grafting poly(hydroxyethylmethacrylate) onto coconut coir pith, CP (a coir industry-based lignocellulosic residue), using potassium peroxydisulphate as an initiator and in the presence of N,N'-methylenebisacrylamide as a cross-linking agent. The adsorbent was characterized with the help of infrared spectroscopy, powder X-ray diffraction, scanning electron microscopy, and potentiometric titrations. The ability of PGCP-COOH to remove Hg(II) from aqueous solutions was assessed using batch adsorption technique under kinetic and equilibrium conditions. Adsorbent exhibits very high adsorption potential for Hg(II) and more than 99.0% removal was achieved in the pH range 5.5-8.0. Adsorption process was found to follow first-order-reversible kinetics. An increase of ionic strength of the medium caused a decrease in metal removal, indicating the occurrence of outer-sphere surface complex mechanism. The equilibrium data were fitted well by the Freundlich isotherm model (R(2)=0.99; chi(2)=1.81). The removal efficiency was tested using chlor-alkali industry wastewater. Adsorption isotherm experiments were also conducted for comparison using a commercial carboxylate-functionalized ion exchanger, Ceralite IRC-50. Regeneration experiments were tried for four cycles and results indicate a capacity loss of <9.0%.

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.

Wear and friction behaviour of soft particles filled random direction short GFRP composites

International Nuclear Information System (INIS)

Srivastava, V.K.; Wahne, S.

2007-01-01

The random direction short E-glass fibre reinforced epoxy resin composites filled with the particles of mica and tricalcium phosphate (TCP) were prepared by hand lay-up method. The wear and friction behaviour of random direction short E-glass fibre reinforced epoxy resin (GFRP) composites sliding against AISI-1045 steel in a pin-on-disc configuration were evaluated on a TR-20LE wear and friction tester. The microhardness, density, tensile strength and compressive strength of the filled and unfilled mica as well as TCP particles were determined. The morphology of the worn surfaces of the unfilled and filled random E-glass fibre composites and the transfer films were analyzed with the scanning electron microscope. It was found that the particles as the fillers contributed significantly to improve the mechanical properties and wear resistance of the E-glass fibre. This was because the particulates as the fillers contributed to enhance the bonding strength between the fibre and the epoxy resin. Moreover, the wear and friction properties of the random E-glass fibre composites were reduced by increasing filler weight of particles

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.)

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.

The relationship between critical flux and fibre movement induced by bubbling in a submerged hollow fibre system.

Science.gov (United States)

Wicaksana, F; Fan, A G; Chen, V

2005-01-01

Bubbling has been used to enhance various processes. In this paper we deal with the effect of bubbling on submerged hollow fibre membranes, where bubbling is applied to prevent severe membrane fouling. Previous work with submerged hollow fibres has observed that significant fibre movement can be induced by bubbling and that there is a qualitative relationship between fibre movement and filtration performance. Therefore, the aim of the present research has been to analyse the link between bubbling, fibre movement and critical flux, identified as the flux at which the transmembrane pressure (TMP) starts to rise. Tests were performed on vertical isolated fibres with a model feed of yeast suspension. The fibres were subject to steady bubbling from below. The parameters of interest were the fibre characteristics, such as tightness, diameter and length, as well as feed concentration. The results confirmed that the critical fluxes are affected by the fibre characteristics and feed concentration. Higher critical flux values can be achieved by using loose fibres, smaller diameters and longer fibres. The enhancement is partially linked to fibre movement and this is confirmed by improved performance when fibres are subject to mechanical movement in the absence of bubbling.

Evaluation of Thermal and Thermomechanical Behaviour of Bio-Based Polyamide 11 Based Composites Reinforced with Lignocellulosic Fibres

Directory of Open Access Journals (Sweden)

Helena Oliver-Ortega

2017-10-01

Full Text Available In this work, polyamide 11 (PA11 and stone ground wood fibres (SGW were used, as an alternative to non-bio-based polymer matrices and reinforcements, to obtain short fibre reinforced composites. The impact of the reinforcement on the thermal degradation, thermal transitions and microstructure of PA11-based composites were studied. Natural fibres have lower degradation temperatures than PA11, thus, composites showed lower onset degradation temperatures than PA11, as well. The thermal transition and the semi-crystalline structure of the composites were similar to PA11. On the other hand, when SGW was submitted to an annealing treatment, the composites prepared with these fibres increased its crystallinity, with increasing fibre contents, compared to PA11. The differences between the glass transition temperatures of annealed and untreated composites decreased with the fibre contents. Thus, the fibres had a higher impact in the composites mechanical behaviour than on the mobility of the amorphous phase. The crystalline structure of PA11 and PA11-SGW composites, after annealing, was transformed to α’ more stable phase, without any negative impact on the properties of the fibres.

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).

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.

Can the gastrointestinal microbiota be modulated by dietary fibre to treat obesity?

Science.gov (United States)

Davis, H C

2018-05-01

Recent research suggests that the human gastrointestinal microbiota is greatly involved in yielding, storing and expending energy from the diet; therefore, it may be a further factor in linking diet to obesity. The gut microbial composition is affected by diet throughout the human lifespan, and is highly dynamic and efficient in response to dietary alterations in particular to dietary fibre intake. Short-chained fatty acids (SCFA) are the bi-product of fibre fermentation and have both obesogenic and anti-obesogenic properties. The production of specific forms of SCFAs depends on the microbes available in the gut and the type of fibre ingested. The gut microbiome associated with healthy lean individuals has a higher microbial biodiversity and a greater Bacteroidete to Firmicute ratio compared to the obese individuals associated with microbiome. These gut microbial associations are similar to those seen in individuals with high and low dietary fibre intakes, respectively. Metabolites generated by Bacteroidetes and Firmicutes include the three main SCFA related to obesity, namely butyrate, acetate and propionate. However, neither Bacteroidetes nor Firmicutes is purely causative or purely preventative of obesity. More research is crucial in linking the various types of fibre with particular SCFA production and the microbiome it promotes before suggesting that dietary fibre modulation of the gut microbiome can treat obesity. However, the long-term dietary trend plays the principal role in assembling the diversity and abundance of gut microbes; thus, a sustained diet high in fibre may help prevent obesity by promoting a microbiome associated with a lean phenotype.

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

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...

Environmental effect on the mechanical properties of commingled-yarn-based carbon fibre/polyamide 6 composites

DEFF Research Database (Denmark)

Raghavalu Thirumalai, Durai Prabhakaran; Toftegaard, Helmuth Langmaack

2014-01-01

The main objective of this experimental investigation was to evaluate the changes from accelerated ageing on selected properties of carbon fibre/polyamide 6 composites based on hybrid yarns. In this study, two types of mechanical tests were performed to measure the environmental influence...... on the material properties. They are three-point bending to measure the flexural strength and stiffness, and short beam three-point bending to measure the interlaminar shear strength. The 10-mm-thick quasi-isotropic carbon fibre/polyamide 6 composites with 52% volume fraction of carbon fibre to be tested were...... temperature. The interlaminar shear strength values also drop to about 75% at both −45 and 115. Extreme temperatures and long-time exposure to humidity of quasi-isotropic carbon fibre/polyamide 6 laminates can thus reduce the bending stiffness and strength by up to 35% and the interlaminar shear strength...

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...

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…

Durability and inflammogenic impact of carbon nanotubes compared with asbestos fibres

Directory of Open Access Journals (Sweden)

Clark Steve

2011-05-01

inflammogenic effect in the peritoneal cavity assay used here. Conclusions These results support the view that carbon nanotubes are generally durable but may be subject to bio-modification in a sample-specific manner. They also suggest that pristine carbon nanotubes, either individually or in rope-like aggregates of sufficient length and aspect ratio, can induce asbestos-like responses in mice, but that the effect may be mitigated for certain types that are less durable in biological systems. Results indicate that durable carbon nanotubes that are either short or form tightly bundled aggregates with no isolated long fibres are less inflammogenic in fibre-specific assays.

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.

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.

Behaviour of AR glass fibre for building structural applications

Directory of Open Access Journals (Sweden)

Miravete, A.

2005-12-01

Full Text Available The AR glass reinforcement fibres were designed to resist the alkalis from the concrete. This is the main reason for its utilisation as a short-fibre-reinforcement of mortar and concrete for the last decades. Originally, the AR glass fibre sizing was not compatible with synthetic resins, so that this type of reinforcement was applied exclusively to mortar and concrete matrices. Recently, due to the developments of sizing, which are compatible with synthetic resins, the AR- glass fibres may be used as reinforcement of organic matrix composite materials, broadening the range of structural applications. The mechanical properties of AR glass fibre and organic matrix composite materials will be studied in this paper. First, the behaviour of this material under stress corrosion will be analysed. Their mass loss will be compared to E, C, and boron free glass fibres. Second, an experimental study dealing with 3P test bending and short beam ofAR glass fibre/polyester will de described with the goal of obtaining their Young modulus and tensile and interlaminar shear strengths. Finally, these experimental results will be compared to E glass fibre/polyester and several conclusions about their structural applications will be drawn.

El vidrio AR y su presentación en forma de fibras de refuerzo, fue diseñado para ser inerte a los álcalis de los cementos. Por este motivo se viene utilizando desde hace varias décadas como refuerzo de morteros y hormigones en forma de fibra corta. El ensimaje que estas fibras de vidrio de refuerzo A R presentaba en su origen no era compatible con resinas de tipo sintéticas, por lo que el refuerzo era exclusivo para cementos y hormigones fuera cual fuera la aplicación, formato o proceso productivo. Recientemente, gracias al desarrollo específico de ensimajes especiales acordes a las fibras de vidrio AR ha aparecido la misma tipología de vidrio AR como refuerzo en forma de fibra continua compatible con resinas sint

New insights into the toxicity of mineral fibres: A combined in situ synchrotron μ-XRD and HR-TEM study of chrysotile, crocidolite, and erionite fibres found in the tissues of Sprague-Dawley rats.

Science.gov (United States)

Gualtieri, Alessandro F; Bursi Gandolfi, Nicola; Pollastri, Simone; Burghammer, Manfred; Tibaldi, Eva; Belpoggi, Fiorella; Pollok, Kilian; Langenhorst, Falko; Vigliaturo, Ruggero; Dražić, Goran

2017-05-15

Along the line of the recent research topic aimed at understanding the in vivo activity of mineral fibres and their mechanisms of toxicity, this work describes the morpho-chemical characteristics of the mineral fibres found in the tissues of Sprague-Dawley rats subjected to intraperitoneal/intrapleural injection of UICC chrysotile, UICC crocidolite and erionite-Na from Nevada (USA). The fibres are studied with in situ synchrotron powder diffraction and high resolution transmission electron microscopy to improve our understanding of the mechanisms of toxicity of these mineral fibres. In contact with the tissues of the rats, chrysotile fibres are prone to dissolve, with leaching of Mg and production of a silica rich relict. On the other hand, crocidolite and erionite-Na fibres are stable even for very long contact times within the tissues of the rats, showing just a thin dissolution amorphous halo. These findings support the model of a lower biopersistence of chrysotile with respect to crocidolite and erionite-Na but the formation of a silica-rich fibrous residue after the pseudo-amorphization of chrysotile may justify a higher cytotoxic potential and intense inflammatory activity of chrysotile in the short term in contact with the lung tissues. Copyright © 2017 Elsevier B.V. All rights reserved.

Economic production and processing of agricultural fibre plants for high quality applications in automotive, building and furniture industry

Energy Technology Data Exchange (ETDEWEB)

Pecenka, R.; Furll, C.; Gusovius, H.J. [Leibniz Inst. for Agricultural Engineering, Potsdam (Germany)

2010-07-01

The demand for high-quality fibres and shives from hemp and flax as an alternative raw material for the automotive and building industry is increasing. Fibres are used primarily for composite reinforcement instead of synthetic fibres. Shives are used for animal bedding, but processing trials in wood industry for the production of low weight particle boards from shives are also very promising. Fibre producers require experience in cultivation and harvesting as well as modern processing technologies in order to supply flax fibres or shives at competitive prices under the changing conditions of international raw material markets. A complete processing line has been developed, installed and tested at the Leibniz Institute for Agricultural Engineering (ATB) to study all the processing stages of fibre production. The new ATB line can produce high quality fibres and shives from retted and unretted hemp, flax and oilseed flax straw without technical changes of the machine line. The ATB pilot plant has been operated by a cooperation of farmers since 2008. Experience from industrial operation has been used to develop a modern fibre processing line with a throughput of up to 5 t per h hemp straw in only one short line.

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)

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.

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.

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.

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...

Mercury(II) removal from aqueous solutions and wastewaters using a novel cation exchanger derived from coconut coir pith and its recovery

Energy Technology Data Exchange (ETDEWEB)

Anirudhan, T.S. [Department of Chemistry, University of Kerala, Kariavattom, Trivandrum 695581 (India)], E-mail: tsani@rediffmail.com; Divya, L.; Ramachandran, M. [Department of Chemistry, University of Kerala, Kariavattom, Trivandrum 695581 (India)

2008-09-15

A new adsorbent (PGCP-COOH) having carboxylate functional group at the chain end was synthesized by grafting poly(hydroxyethylmethacrylate) onto coconut coir pith, CP (a coir industry-based lignocellulosic residue), using potassium peroxydisulphate as an initiator and in the presence of N,N'-methylenebisacrylamide as a cross-linking agent. The adsorbent was characterized with the help of infrared spectroscopy, powder X-ray diffraction, scanning electron microscopy, and potentiometric titrations. The ability of PGCP-COOH to remove Hg(II) from aqueous solutions was assessed using batch adsorption technique under kinetic and equilibrium conditions. Adsorbent exhibits very high adsorption potential for Hg(II) and more than 99.0% removal was achieved in the pH range 5.5-8.0. Adsorption process was found to follow first-order-reversible kinetics. An increase of ionic strength of the medium caused a decrease in metal removal, indicating the occurrence of outer-sphere surface complex mechanism. The equilibrium data were fitted well by the Freundlich isotherm model (R{sup 2} = 0.99; {chi}{sup 2} 1.81). The removal efficiency was tested using chlor-alkali industry wastewater. Adsorption isotherm experiments were also conducted for comparison using a commercial carboxylate-functionalized ion exchanger, Ceralite IRC-50. Regeneration experiments were tried for four cycles and results indicate a capacity loss of <9.0%.

Distributed acoustic fibre optic sensors for condition monitoring of pipelines

Science.gov (United States)

Hussels, Maria-Teresa; Chruscicki, Sebastian; Habib, Abdelkarim; Krebber, Katerina

2016-05-01

Industrial piping systems are particularly relevant to public safety and the continuous availability of infrastructure. However, condition monitoring systems based on many discrete sensors are generally not well-suited for widespread piping systems due to considerable installation effort, while use of distributed fibre-optic sensors would reduce this effort to a minimum. Specifically distributed acoustic sensing (DAS) is employed for detection of third-party threats and leaks in oil and gas pipelines in recent years and can in principle also be applied to industrial plants. Further possible detection routes amenable by DAS that could identify damage prior to emission of medium are subject of a current project at BAM, which aims at qualifying distributed fibre optic methods such as DAS as a means for spatially continuous monitoring of industrial piping systems. Here, first tests on a short pipe are presented, where optical fibres were applied directly to the surface. An artificial signal was used to define suitable parameters of the measurement system and compare different ways of applying the sensor.

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.

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

Science.gov (United States)

Liu, He Liang

the common silicate fibres were used. Due to the high solubility of erbium ions in bismuth oxide based erbium-doped fibre (Bi-EDF), a stable and short-cavity fibre ring laser was realized by employing only 0.85 m of Bi-EDF. Ultrawide continuous wavelength tuning range over 100 nm was obtained by using a tuning MEMS filter or scanning fibre FP filter. A very narrow linewidth, single-longitudinal mode fibre ring laser, using an unpumped EDF acting as saturable absorber in the cavity, was realized. The linewidth of the fibre ring laser was measured by two optical mixing methods and about 1.17 kHz linewidth was measuring by the delayed self-heterodyne technique. (Abstract shortened by UMI.)

Additive manufacturing of short and mixed fibre-reinforced polymer

Science.gov (United States)

Lewicki, James; Duoss, Eric B.; Rodriguez, Jennifer Nicole; Worsley, Marcus A.; King, Michael J.

2018-01-09

Additive manufacturing of a fiber-reinforced polymer (FRP) product using an additive manufacturing print head; a reservoir in the additive manufacturing print head; short carbon fibers in the reservoir, wherein the short carbon fibers are randomly aligned in the reservoir; an acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin in the reservoir, wherein the short carbon fibers are dispersed in the acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin; a tapered nozzle in the additive manufacturing print head operatively connected to the reservoir, the tapered nozzle produces an extruded material that forms the fiber-reinforced polymer product; baffles in the tapered nozzle that receive the acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin with the short carbon fibers dispersed in the acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin; and a system for driving the acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin with the short carbon fibers dispersed in the acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin from the reservoir through the tapered nozzle wherein the randomly aligned short carbon fibers in the acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin are aligned by the baffles and wherein the extruded material has the short carbon fibers aligned in the acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin that forms the fiber-reinforced polymer product.

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

to 25 kGy. Still at this total dose, we did not observe significant change in the optical transmission due to radiation. From the point of view of radiation hardness, this fibre appears to be promising for thermography applications but several intrinsic shortcomings, mainly its high intrinsic absorption (∼ 1 dB/m ) and strong optical sensitivity regarding the bending radius, limit the applicability of this technology. Further irradiation tests are currently in progress to evaluate the radiation resistance of sapphire and chalcogenide fibres. At the time of the conference, we will compare the radiation resistance of all these IR fibres. For the time being, we conclude that zirconium fibres could be used in the 3-4 μm region if the radiation flux does not exceed 1 Gy/s and if the fibre is simultaneously heated around 100 o C. For wavelength above 3 μm, hollow fibres appears to be a good candidate but for short fibre length only. (author)

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...

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.

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

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

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)

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)

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

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

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...

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

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.

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...

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...

Steel fibre concrete, a safer material for reactor construction. A general theory for rupture prediction

International Nuclear Information System (INIS)

Rammant, J.P.; Van Laethem, L.; Backx, E.

1977-01-01

The effect of steel fibre reinforcement on the mechanical behavior of concrete reactor structures is studied. It is shown that this material leads to a higher safety factor for highly stressed concrete structures like prestressed concrete pressure vessels. The reinforcement of concrete with short steel fibres results clearly in a fundamental change of the material properties. The study comprises basic experiments, the elaboration of an expression of the material laws, the development of a general computer program and the comparison of computational results with more elaborate experiments. Basic experimental work is conducted to determine the material characteristics of the fibre reinforced concrete. It is shown how the fibre reinforcement mechanism is translated into mathematical formulae by expressing the principal characteristics as matrix relationships. These relationships describe the elasto-plastic behavior and the cracked behavior. Probabilistic principles are used to express to fibre efficiency, such that a general stress-strain relationship is incorporated in a subsequent computer program. A general finite element program is developed which includes the new matrix relationships, the pull-out of fibres and the general stress-strain equations. A nonlinear calculation method gives the propagation of the distributed cracks with increasing load untill failure of the structure. Similarly, thermal cycling conditions are accounted for. For example the crack propagation in a fibre reinforced beam was measured by the photostress coating technique: the comparison with the computed crack propagation reveals an excellent agreement. Other comparative studies on simple structural parts are also reported

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.

Electrostatic flocking of chitosan fibres leads to highly porous, elastic and fully biodegradable anisotropic scaffolds.

Science.gov (United States)

Gossla, Elke; Tonndorf, Robert; Bernhardt, Anne; Kirsten, Martin; Hund, Rolf-Dieter; Aibibu, Dilibar; Cherif, Chokri; Gelinsky, Michael

2016-10-15

Electrostatic flocking - a common textile technology which has been applied in industry for decades - is based on the deposition of short polymer fibres in a parallel aligned fashion on flat or curved substrates, covered with a layer of a suitable adhesive. Due to their highly anisotropic properties the resulting velvet-like structures can be utilised as scaffolds for tissue engineering applications in which the space between the fibres can be defined as pores. In the present study we have developed a fully resorbable compression elastic flock scaffold from a single material system based on chitosan. The fibres and the resulting scaffolds were analysed concerning their structural and mechanical properties and the biocompatibility was tested in vitro. The tensile strength and Young's modulus of the chitosan fibres were analysed as a function of the applied sterilisation technique (ethanol, supercritical carbon dioxide, γ-irradiation and autoclaving). All sterilisation methods decreased the Young's modulus (from 14GPa to 6-12GPa). The tensile strength was decreased after all treatments - except after the autoclaving of chitosan fibres submerged in water. Compressive strength of the highly porous flock scaffolds was 18±6kPa with a elastic modulus in the range of 50-100kPa. The flocked scaffolds did not show any cytotoxic effect during indirect or direct culture of human mesenchymal stem cells or the sarcoma osteogenic cell line Saos-2. Furthermore cell adhesion and proliferation of both cell types could be observed. This is the first demonstration of a fully biodegradable scaffold manufactured by electrostatic flocking. Most tissues possess anisotropic fibrous structures. In contrast, most of the commonly used scaffolds have an isotropic morphology. By utilising the textile technology of electrostatic flocking, highly porous and clearly anisotropic scaffolds can be manufactured. Flocking leads to parallel aligned short fibres, glued on the surface of a substrate

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

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...

Parametric study of a polymer-coated fibre-optic humidity sensor

International Nuclear Information System (INIS)

David, Nigel A; Wild, Peter M; Djilali, Ned

2012-01-01

A relative humidity sensor based on polymer-coated optical fibre Bragg gratings is presented. This fully functional sensor has response time and resolution comparable to the current capacitive relative humidity (RH) sensors, but with greater applicability. Numerical and experimental methods are used to determine the effects of coating thickness and fibre diameter on the response time and sensitivity of Bragg gratings coated with Pyralin. Transient results indicate that coating thicknesses of less than 4 μm are needed to achieve a response time of 5 s, competitive with commercial capacitive RH sensors. Using thin coatings of ∼2 μm, for a short response time, sensors with reduced fibre diameter were fabricated and tested under steady-state, transient and saturated conditions. By chemical etching from 125 to 20 μm, the sensitivity increased by a factor of 7. Such an increase in sensitivity allows for the resolution and response time of the Pyralin-coated sensor to be comparable to commercial capacitive RH sensors. These characteristics, in addition to the sensor’s rapid recovery from saturation in liquid water, indicate good potential for use of this sensor design in applications where electronic RH sensors are not suitable. (paper)

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

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.

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...

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...

Measurements and radiation tests on scintillating fibres for the LHCb SciFi project

CERN Document Server

Joram, Christian; Shatalov, Pavel

2014-01-01

This note describes a number of measurements and a radiation test performed on the baseline fibre of the LHCb SciFi upgrade project. These include measurements of the optical attenuation length - globally and wavelength resolved -, measurements of the photoelectric yield, and finally the assessment of the impact of proton irradiation on these quantities. The fibres were irradiated at the CERN PS with 24 GeV/c protons up to a fluence of 7•10$^{13}$ p/cm$^2$ equivalent to an ionizing dose of about 22 kGy. Measurements on the fibres, in particular in view of possible recovery effects, are still ongoing and the report is expected to be updated in the coming months. This report is meant as backup document for the LHCb internal SciFi review in February 2013. It had to be produced in a short available time. Missing information will be added and style as well as formatting will be improved in the forthcoming version.

Developing connectivity of the phases in a short fibre reinforced aluminium piston alloy subjected to creep; Entwicklung der Konnektivitaet der Phasen in einer kurzfaserverstaerkten Aluminium-Kolbenlegierung unter Kriechbelastung

Energy Technology Data Exchange (ETDEWEB)

Requena, G.C.; Degischer, H.P.; Marks, E.D. [Institute of Materials Science and Technology, Vienna University of Technology, Karlsplatz 13/308 - A1040 Vienna (Australia); Boller, E. [European Synchrotron Radiation Facility (France)

2007-11-15

The evolution of the micro-structure during creep of an AlSi12CuMgNi piston alloy with 15 vol% of Al{sub 2}O{sub 3} short fibres is investigated by means of synchrotron micro-tomography. The results reveal a 3D morphology of the rigid phases in the composite: the eutectic-Si, the short fibres and the Fe- and Ni-rich intermetallic particles, which form an interconnected hybrid reinforcement. The connectivity of these phases increases during creep exposure at 300 C due to the diffusion induced ripening of Si and of the intermetallic particles. The hybrid reinforcement reaches almost complete percolation after 6400 h of creep exposure. The fibre orientation analysed by three-dimensional Fast Fourier Transformation does not indicate any reorientation of the fibres along the load direction. The formerly observed strengthening effect during creep exposure is attributed to the increasing load carrying capacity of the interconnected hybrid reinforcement. The analysis of creep damage during secondary creep stage shows the increase of the void volume fraction by a factor of 2 with respect to the void content from processing, while the number of voids per volume remains practically constant. The voids are located at interfaces of the rigid phases and not within the {alpha}-aluminium matrix. (Abstract Copyright [2007], Wiley Periodicals, Inc.) [German] Das drei-dimensionale Gefuege einer AlSi12CuMgNi-Kolbenlegierung verstaerkt mit 15 vol% Al{sub 2}O{sub 3}-Kurzfasern wird mittels Synchrotron Mikro-Tomographie dargestellt. Der loesungsgegluehte Ausgangszustand enthaelt ein zusammenhaengendes Netzwerk aus Kurzfasern und Fe- und Ni-reichen Primaerausscheidungen, das darueber hinaus durch eine Vielzahl von Si-Bruecken des Eutektikums verbunden wird. Die Konnektivitaet nimmt mit der Dauer der Kriechbelastung bei 300 C zu, besonders durch die Reifung der Si-Teilchen, die zu einer in sich zusammenhaengenden Struktur zusammenwachsen, die mit dem bereits vorhandenen Netzwerk mit den

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.

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.

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.)

Physico-mechanical properties of coir fiber/LDPE composites: Effect of chemical treatment and compatibilizer

Energy Technology Data Exchange (ETDEWEB)

Prasad, Nirupama; Agarwal, Vijay Kumar; Sihha, Shishir [Indian Institute of Technology Roorkee, Uttrakhand (India)

2015-12-15

Coir fiber/low density polyethylene (LDPE) composites were fabricated with different fiber loading (10- 30 wt%) using compression molding technique. A fiber loading of 20 wt% was found optimum, with maximum mechanical properties. Further, the effect of fiber treatment (alkali and acrylic acid) and compatibilizer (MA-g-LDPE) incorporation on the mechanical and water absorption properties of the LDPE composites were studied and compared. The results showed that MA-g-LDPE incorporation into untreated and treated fiber composites led to improved mechanical properties and water resistance compared with the same composite formulation without MA-g-LDPE. However, treated fiber composites with MA-g-LDPE showed lower mechanical properties than untreated fiber without MA-g- LDPE, due to the removal of hydroxyl groups from the hemicellulose and lignin region of the fiber and degradation of fibers by chemical attack. From SEM studies on the tensile fractured composite samples, a good relationship has been observed between the morphological and mechanical properties.

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....

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

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...

Sustainable Absorption Panels from Agricultural Wastes

Directory of Open Access Journals (Sweden)

Ismail F.Z.

2014-01-01

Full Text Available Noise has become a serious environmental problem and there are demands for alternative sustainable materials which capable to reduce the noise level at various frequency ranges. Therefore, the aim of this research is to study the potential of turning the agricultural waste and waste paper into a sound absorption panel. For the purpose of this study, combination of two materials was under studied; coconut coir fibre from agriculture waste and shredded waste paper from the office. There were two main objective of the research; first is to develop absorption panels from coconut coir powder that available locally with a combination of shredded paper at different percentage of mixture. Second objective is to identify the absorption rate of the panels. The study encompasses the fabrication of the particle board using the coconut husk powder mix with shredded waste paper and using the gypsum powder as the binder for the two materials. Four acoustic panels of size 0.5m x 0.5m and 0.012 m thick were fabricated with different mix ratio; 25% of coconut coir powder mixed with 75% of shredded waste papers for sample 1, 50% both of the material for sample 2, 75% of coconut coir powder mixed with 25% of shredded waste paper for sample 3, and lastly 100% of coconut coir powder for sample 4. The absorption coefficient of the panels was tested in a reverberation chamber and in accordance with ISO 354:1985 standards. Based on the results, sample 1 gave the highest absorption coefficient compared to sample 2, 3 and 4. It can be concluded that the acoustic panel made from a mixture of 25% coconut coir powder with 75% shredded waste paper provided higher absorption coefficient compared to the performance of the other samples. This might be caused by the size of the coir powder which is very small, creating less void space in between the panel and thus causing it to absorb less sound. Since sound absorption is very much affected by the availability of void space of

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)

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)

Study of physical and sound absorbing property of epoxy blended coir dust biocomposite

Science.gov (United States)

Nath, G.; Mishra, S. P.

2016-09-01

Reinforcement biocomposite has gained more attention recently due to its low cost, abundantly availability, low density, specific properties, easy method of separation, enhanced energy recovery, CO2 neutrality, biodegradability and recyclable in nature. As a waste product of coconut fruit, the coconut coir dust (CCD) obtained from the coconut husk. The biocomposite material prepared from the CCD modified with the proper blended solution with the help of ultrasonic technique. The study of adiabatic compressibility of acetone / water (70/30) worth its blending property for bleaching of CCD. The biocomposite material of CCD was prepared with epoxy resin. The different physical properties such as sound absorption coefficient, thermal conductivity and electrical conductivity were measured. The morphological study of biocomposite and measurement of sound absorption coefficient shows good evidence of sound absorbing characteristics of biocomposite of CCD. The sound absorption property of composite material shows a significant result where as the thermal conductivity and electrical conductivity executes a weak result. Thus biocomposite of CCD can acts as a good sound absorber and band conductor of heat and electric current.

Colonic production of butyrate in patients with previous colonic cancer during long-term treatment with dietary fibre (Plantago ovata seeds)

DEFF Research Database (Denmark)

Nordgaard, I; Hove, H; Clausen, M R

1996-01-01

BACKGROUND: Butyrate has antineoplastic properties against colorectal cancer cells and is the preferred oxidative substrate for colonocytes. Like acetate and propionate (short-chain fatty acids; SCFAs), butyrate is produced by colonic fermentation of dietary fibre. METHODS: Twenty patients resected...... for colorectal cancer were treated with 20 g/day of the fibre Plantago ovata seeds for 3 months, which increased the intake of fibre by 17.9 +/- 0.8 g/day, from basal levels of 19.2 +/- 1.7 g/day; 17 patients completed the study. Faecal samples were obtained on eight occasions, twice before treatment......, and monthly three times during and three time after treatment. RESULTS: One month of fibre therapy increased faecal concentrations of butyrate by 42 +/- 12% (from 13.2 +/- 1.2 to 19.3 +/- 3.0 mmol/l; P

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

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...

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...

Influence of fibre distribution and grain size on the mechanical behaviour of friction stir processed Mg–C composites

Energy Technology Data Exchange (ETDEWEB)

Mertens, A., E-mail: anne.mertens@ulg.ac.be [Université de Liège, Faculty of Applied Science, A& M Department, Metallic Materials Science Unit (Belgium); Simar, A. [Université catholique de Louvain, Institute of Mechanics, Materials and Civil Engineering (Belgium); Adrien, J.; Maire, E. [Institut National des Sciences Appliquées de Lyon (INSA Lyon), MATEIS Laboratory (France); Montrieux, H.-M. [Université de Liège, Faculty of Applied Science, A& M Department, Metallic Materials Science Unit (Belgium); Delannay, F. [Université catholique de Louvain, Institute of Mechanics, Materials and Civil Engineering (Belgium); Lecomte-Beckers, J. [Université de Liège, Faculty of Applied Science, A& M Department, Metallic Materials Science Unit (Belgium)

2015-09-15

Short C fibres–Mg matrix composites have been produced by friction stir processing sandwiches made of a layer of C fabric stacked between two sheets of Mg alloy AZ31B or AZ91D. This novel processing technique can allow the easy production of large-scale metal matrix composites. The paper investigates the microstructure of FSPed C fibre–Mg composites in relation with the fragmentation of the C fibres during FSP and their influence on the tensile properties. 3D X-ray tomography reveals that the fibres orient like onion rings and are more or less fragmented depending on the local shear stress during the process. The fibre volume fraction can be increased from 2.3% to 7.1% by reducing the nugget volume, i.e. by using a higher advancing speed in AZ31B alloy or a stronger matrix alloy, like AZ91D alloy. A higher fibre volume fraction leads to a smaller grain size which brings about an increase of the composite yield strength by 15 to 25%. However, a higher fibre volume fraction also leads to a lower fracture strain. Fracture surface observations reveal that damage occurs by fibre/matrix decohesion along fibres oriented perpendicularly to the loading direction. - Graphical abstract: Display Omitted - Highlights: • C–Mg MMCs were produced by FSP sandwiches made of a C fabric between Mg sheets. • Fibre fragmentation and erosion is larger when the temperature reached during FSP is lower. • A lower advancing speed brings a lower fibre volume fraction and a lower grain size. • X-ray tomography reveals that fibres orient along the FSP material flow. • The fibres and grain size reduction increase the yield strength by 15 to 25%.

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...

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)

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...

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...

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

Effects of dietary fibre and protein on urea transport across the cecal mucosa of piglets

NARCIS (Netherlands)

Stumpff, F.; Lodemann, U.; Kessel, A.G. van; Pieper, R.; Klingspor, S.; Wolf, K. van der; Martens, H.; Zentek, J.; Aschenbach, J.R.

2013-01-01

In ruminants, gastrointestinal recycling of urea is acutely enhanced by fibre-rich diets that lead to high ruminal concentration of short chain fatty acids (SCFA), while high ammonia has inhibitory effects. This study attempted to clarify if urea flux to the porcine cecum is similarly regulated.

Development of a Brillouin scattering based distributed fibre optic strain sensor

Science.gov (United States)

Brown, Anthony Wayne

2001-07-01

The parameters of the Brillouin spectrum of an optical fibre depend upon the strain and temperature conditions of the fibre. As a result, fibre optic distributed sensors based on Brillouin scattering can measure strain and temperature in arbitrary regions of a sensing fibre. In the past, such sensors have often been demonstrated under laboratory conditions, demonstrating the principle of operation. Although some field tests of temperature sensing have been reported, the actual deployment of such sensors in the field for strain measurements has been limited by poor spatial resolution (typically 1 m or more) and poor strain accuracy (+/-100 muepsilon). Also, cross-sensitivity of the Brillouin spectrum to temperature further reduces the accuracy of strain measurement while long acquisition times hinders field use. The high level of user knowledge and lack of automation required to operate the equipment is another limiting factor of the only commercially available unit. The potential benefits of distributed measurements are great for instrumentation of civil structures provided that the above limitations are overcome. However, before this system is used with confidence by practitioners, it is essential that it can be effectively operated in field conditions. In light of this, the fibre optics group at the University of New Brunswick has been developing an automated system for field measurement of strain in civil structures, particularly in reinforced concrete. The development of the sensing system hardware and software was the main focus of this thesis. This has been made possible, in part, by observation of the Brillouin spectrum for the case of using very short light pulses (performance to measure strain to an accuracy of 10 muepsilon; and allow the simultaneous measurement of strain and temperature to an accuracy of 204 muepsilon and 3°C are presented. Finally, the results of field measurement of strain on a concrete structure are presented.

An ultra-wideband tunable multi-wavelength Brillouin fibre laser based on a semiconductor optical amplifier and dispersion compensating fibre in a linear cavity configuration

International Nuclear Information System (INIS)

Zulkifli, M Z; Ahmad, H; Hassan, N A; Jemangin, M H; Harun, S W

2011-01-01

A multi-wavelength Brillouin fibre laser (MBFL) with an ultra-wideband tuning range from 1420 nm to 1620 nm is demonstrated. The MBFL uses an ultra-wideband semiconductor optical amplifier (SOA) and a dispersion compensating fibre (DCF) as the linear gain medium and nonlinear gain medium, respectively. The proposed MBFL has a wide tuning range covering the short (S-), conventional (C-) and long (L-) bands with a wavelength spacing of 0.08 nm, making it highly suitable for DWDM system applications. The output power of the observed Brillouin Stokes ranges approximately from -5.94 dBm to -0.41 dBm for the S-band, from -4.34 dBm to 0.02 dBm for the C-band and from -2.19 dBm to 0.39 dBm for the L-band. The spacing between each adjacent wavelengths of all the three bands is about 0.08 nm, which is approximately 10.7 GHz for the frequency domain. (lasers)

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 networks for safeguards applications

International Nuclear Information System (INIS)

Smith, B.G.R.; Chare, P.; Barrier, A.

1991-01-01

The Euratom Safeguards Directorate has recently installed a fibre optic network in a new large scale nuclear facility in the European Communities. The selection, installation and commissioning of the fibre optic network is discussed from the viewpoint of network topology, physical testing, trouble shooting and authentication. The future use of fibre optic networks for safeguards applications is discussed

Demonstration of the postcommissural fibres of the fornix in short-inversion time inversion-recovery imaging on a high-field system

Energy Technology Data Exchange (ETDEWEB)

Saeki, N.; Kansaku, K.; Higuchi, Y.; Yamaura, A. [Dept. of Neurological Surgery, Chiba University School of Medicine (Japan); Kawano, K.; Iijima, T. [Electrotechnical Lab., Tsukuba (Japan); Inoue, N. [GE Yokagawa Medical Systems, Tokyo (Japan)

2001-07-01

Short-inversion time inversion-recovery (STIR) imaging using a 3 tesla system was assessed to reveal the postcommissural fibres (PF) of the fornix, which have rarely been highlighted neuroradiologically in the clinical setting. We studied 27 normal subjects. Sequence parameters were TR/TE/TI 8000/52/150 ms. STIR was expected to take advantage of the high signal-to-noise ratio of a high-field system, due to the long repetition time. PF were identifiable in axial and coronal slices in all cases. They were bordered anteriorly and superiorly by the anterior commissure and posteriorly and inferiorly by the mamillary body. Behind the anterior commissure, they ran in an arch-shaped posterior and inferior course in the hypothalamic nuclei and joined the mamillary body anterolaterally. They usually extended through three 3-mm slices (with 1 mm interslice gap) in anteroposterior and vertical dimensions. Little variation was observed in their course or size. Demonstration of the PF would provide a more detailed correlation of human neuroanatomy to hypothalamic function and individualised understanding of hypothalamic pathology and influence therapy. (orig.)

Demonstration of the postcommissural fibres of the fornix in short-inversion time inversion-recovery imaging on a high-field system

International Nuclear Information System (INIS)

Saeki, N.; Kansaku, K.; Higuchi, Y.; Yamaura, A.; Kawano, K.; Iijima, T.; Inoue, N.

2001-01-01

Short-inversion time inversion-recovery (STIR) imaging using a 3 tesla system was assessed to reveal the postcommissural fibres (PF) of the fornix, which have rarely been highlighted neuroradiologically in the clinical setting. We studied 27 normal subjects. Sequence parameters were TR/TE/TI 8000/52/150 ms. STIR was expected to take advantage of the high signal-to-noise ratio of a high-field system, due to the long repetition time. PF were identifiable in axial and coronal slices in all cases. They were bordered anteriorly and superiorly by the anterior commissure and posteriorly and inferiorly by the mamillary body. Behind the anterior commissure, they ran in an arch-shaped posterior and inferior course in the hypothalamic nuclei and joined the mamillary body anterolaterally. They usually extended through three 3-mm slices (with 1 mm interslice gap) in anteroposterior and vertical dimensions. Little variation was observed in their course or size. Demonstration of the PF would provide a more detailed correlation of human neuroanatomy to hypothalamic function and individualised understanding of hypothalamic pathology and influence therapy. (orig.)

Mineral fibres and health

International Nuclear Information System (INIS)

Hoskins, J.A.

2001-01-01

The use of inorganic fibrous materials is a comparatively new phenomenon and was uncommon before the Industrial Revolution. Humans evolved in a comparatively fibre-free environment and consequently never fully developed the defence mechanisms needed to deal with the consequences of inhaling fibres. However, the urban environment now has an airborne fibre concentration of around 1 f.l -1 , which is a tenfold increase on the natural background. Any sample of ambient air collected indoors or outdoors will probably contain some mineral fibres, but there is little evidence that these pose any risk to human health. They come from asbestos used in brakes, glass and mineral wools used as insulation and fire proofing of buildings, gypsum from plaster and a variety of types from many sources. Few of these have the potential to do any harm. Asbestos is the only fibre of note but urban levels are insignificant compared to occupational exposures. When the health of cohorts occupationally exposed to the several types of asbestos is studied the problem can be put into perspective. Studies of workers in the chrysotile industry exposed to much higher dust levels than in a factory today show no excess lung cancer or mesothelioma. By comparison those living near crocidolite mines, let alone working in them, may develop asbestos-related disease. As always, dose is the critical factor. Chrysotile is cleared from the lungs very efficiently, only the amphiboles are well retained. The only real health problem comes from the earlier use of asbestos products that may now be old, friable and damaged and made from amphibole or mixed fibre. If though, these are still in good condition, they do not pose a health problem. Asbestos-related diseases are very rare in those not occupationally exposed. Where they exist exposure has nearly always been to crocidolite. (author)

Photonic crystal fibres and effective index approaches

DEFF Research Database (Denmark)

Riishede, Jesper; Libori, Stig E. Barkou; Bjarklev, Anders Overgaard

2001-01-01

Photonic crystal fibres are investigated with an effective index approach. The effective index of both core and cladding is found to be wavelength dependent. Accurate modelling must respect the rich topology of these fibres.......Photonic crystal fibres are investigated with an effective index approach. The effective index of both core and cladding is found to be wavelength dependent. Accurate modelling must respect the rich topology of these fibres....

New Insights into Muscle Fibre Types in Casertana Pig

Directory of Open Access Journals (Sweden)

Salvatore Velotto

2010-01-01

Full Text Available Little is known about the Casertana pig. The aim of this study was to evaluate the effect of sex on histochemical and morphometrical characteristics of muscle fibres (myocytes in this pure breed and to verify the presence of giant fibres as well as vascularity of the muscle. Finally, maximum shortening velocity and isometric tension were measured in single muscle fibres. Sixteen Casertana pigs (8 males, 8 females from a farm in Campania (Italy were slaughtered at one year of age. Muscle tissues were obtained from psoas minor, rhomboideus and longissimus dorsi. Myofibres were stained for myosin adenosine triphosphatase, succinic dehydrogenase, and α-amylase-periodic acid schiff. For all fibre types, the area and perimeter were measured. Slowtwitch oxidative fibres, fast-twitch glycolytic fibres and fast-twitch oxidative-glycolytic fibres were histochemically differentiated; an image-analyzing system was used. The results showed significant differences between the sexes in the size of all three fibre types. The psoas minor muscle had a high percentage of slow-twitch oxidative fibres and contained more capillaries per fibre and per mm2 than rhomboideus and longissimus dorsi, in which fast-twitch glycolytic fibres dominated. The cross-sectional area of all fibre types was larger in longissimus dorsi than in rhomboideus and psoas minor muscles; the giant fibres were present in the longissimus dorsi muscle only. Besides, isometric tension values were higher in fast-twitch glycolytic fibres than in the other ones. Variations in fibre type composition may contribute to meat quality.

Fatigue Damage Evolution in Fibre Composites for Wind Turbine Blades

DEFF Research Database (Denmark)

Jespersen, Kristine Munk

on the micro-scale in the non-crimp fabric based composites used for wind turbine blades. The results show that fibre fractures in the unidirectional (UD) load carrying fibre bundles initiate from off-axis cracks in the thin supporting backing fibre bundles. With an increasing number of fatigue load cycles......, the UD fibre fractures progress gradually into the thickness direction of the UD fibre bundles, which eventually results in final fracture of the fibre composite. It is also found that the UD fibre fracture regions generally grow larger and initiate earlier at cross-over regions of the backing fibre...... bundles than at single backing fibre bundle regions. Furthermore, UD Fibre fractures are only observed to initiate at locations where the backing fibre bundles are ‘in contact’ with a UD fibre bundle. By observing the damage progression in 3D, it is also clear that the UD fibre fractures initiated...

Fibre-optic temperature sensor

International Nuclear Information System (INIS)

Zhao Jie; Liu Zhenyuan.

1993-04-01

This experiment is a kind of nonfunction fibre-optic temperature sensor. It utilizes high-sensitive bimetallic strip for element of measuring temperature. The changing of bimetallic strip alterates intensity of light through fibre-optic. This equipment is simple in structure, subtle in design, extensive in application, and so on. (author). 4 refs, 6 figs, 1 tab

Polarisation effects in fibre lasers

OpenAIRE

Lin, J.T.; Morkel, P.R.; Reekie, L.; Payne, D.N.

1987-01-01

Two orthogonal polarisation eigenmodes have been observed in a single-mode fibre laser. Experimental investigation shows good agreement with theoretical analysis. Both Nd3+ and Er3+-doped single-polarisation single-mode fibre lasers have been demonstrated

Myosin heavy-chain isoform distribution, fibre-type composition and fibre size in skeletal muscle of patients on haemodialysis

DEFF Research Database (Denmark)

Molsted, Stig; Eidemak, Inge; Sorensen, Helle Tauby

2007-01-01

of age-, gender- and BMI-matched untrained control subjects. The aerobic work capacity of the patients was also determined. Results. The MHC composition for I, IIA and IIX isoforms was found to be 35.3%±18.2%, 35.9%±7.1% and 28.9%±15.6%, respectively, findings supported by the ATPase histochemically...... determined fibre-type composition of the vastus lateralis muscle. The mean fibre area of type 1 and 2 fibres was 3283±873 and 3594±1483 µm2, respectively. The MHC composition and the size of the type 1 fibres of the patients on HD were significantly different from those of the control subjects. Conclusions....... The data demonstrate relatively fewer type 1 and consequently more type 2x fibres, with a corresponding change in MHC isoforms (MHC I and MHC IIX) in the skeletal muscle of patiens on HD. Several patients on HD were found to have type 1 (or relative percentage of MHC I) fibres. Such a low percentage...

All-fibre Q-switching YDFL operation with bismuth-doped fibre as saturable absorber

Science.gov (United States)

Muhammad, A. R.; Haris, H.; Arof, H.; Tan, S. J.; Ahmad, M. T.; Harun, S. W.

2018-05-01

We demonstrate the generation of a passively Q-switched ytterbium-doped fibre laser (YDFL) using a bismuth-doped fibre (BDF) as a solid-state fibre saturable absorber (FSA) in a ring cavity. The BDF used has a wide and low absorption band of 5 dB/m at the 1.0 μm region due to the ion transition of ? that occurs around the region. When introduced into a YDFL laser cavity, a stable Q-switched pulse operation was observed and the pulse repetition rate was proportional to the input pump power. It was limited to 72.99 kHz by the maximum power that the laser diode could supply. Meanwhile, the pulse width decreased from 12.22 to 4.85 μs as the pump power was increased from 215.6 to 475.6 mW. The finding suggests that BDF could be used as a potential SA for the development of robust, compact, efficient and low cost Q-switched fibre lasers operating at 1 micron region.

A target fibre study on seats in public houses.

Science.gov (United States)

Kelly, E; Griffin, R M

1998-01-01

A target fibre survey was conducted to assess the random occurrence of a blue wool fibre on seats in public houses throughout the United Kingdom. Fibre tape lifts were taken from 80 seats. Four seats yielded matching fibres and five of these were found on one seat. A total of 292 fibres were identified; nine fibres proved indistinguishable from the target after comparison microscopy, microspectro-photometry and attempts at thin layer chromatography, and two of these fibres were still apparently indistinguishable after TLC analysis although only one dye component was visible.

Fibre laser cutting of polycaprolactone sheet for stents manufacturing: A feasibility study

Science.gov (United States)

Guerra, Antonio J.; Farjas, Jordi; Ciurana, Joaquim

2017-10-01

The role of the stent is temporary and it is limited to the intervention and shortly thereafter. Bioresorbable polymer stents were introduced to overcome this problem, making the stent manufacturing process rather difficult considering the complexity of the material. The stent forecast sale makes constant technology development necessary on this field. The adaptation of the laser manufacturing industry to these new materials is costly, thus further studies employing different sorts of lasers are necessary. This paper aims to explore the feasibility of 1.08 μm wavelength fibre laser to cut polycaprolactone sheet, which is especially interesting for long-term implantable devices, such as stents. The laser cut samples were analysed by Differential Scanning Calorimetry (DSC), Tensile Stress Test, and Optical Microscopy in order to study the effects of the laser process over the workpiece. The parameters measured were: taper angle, dimensional precision, material structure changes and mechanical properties changes. Results showed a dimensional precision above 95.75% with a taper angle lower than 0.033°. The laser ablation process has exhibited a minor influence upon material properties. Results exhibit the feasibility of fibre laser to cut polycaprolactone, making the fibre laser an alternative to manufacture stents.

The hygroscopic behavior of plant fibres: a review

Directory of Open Access Journals (Sweden)

Amandine eCélino

2014-01-01

Full Text Available Environmental concern has resulted in a renewed interest in bio-based materials. Among them, plant fibres are perceived as an environmentally friendly substitute to glass fibres for the reinforcement of composites, particularly in automotive engineering. Due to their wide availability, low cost, low density, high-specific mechanical properties and eco-friendly image, they are increasingly being employed as reinforcements in polymer matrix composites. Indeed, their complex microstructure as a composite material makes plant fibre a really interesting and challenging subject to study. Research subjects about such fibres are abundant because there are always some issues to prevent their use at large scale (poor adhesion, variability, low thermal resistance, hydrophilic behavior. The choice of natural fibres rather than glass fibres as filler yields a change of the final properties of the composite. One of the most relevant differences between the two kinds of fibre is their response to humidity. Actually, glass fibres are considered as hydrophobic whereas plant fibres have a pronounced hydrophilic behavior. Composite materials are often submitted to variable climatic conditions during their lifetime, including unsteady hygroscopic conditions. However, in humid conditions, strong hydrophilic behaviour of such reinforcing fibres leads to high level of moisture absorption in wet environments. This results in the structural modification of the fibres and an evolution of their mechanical properties together with the composites in which they are fitted in. Thereby, the understanding of these moisture absorption mechanisms as well as the influence of water on the final properties of these fibres and their composites is of great interest to get a better control of such new biomaterials. This is the topic of this review paper.

The hygroscopic behavior of plant fibres: a review

Science.gov (United States)

Célino, Amandine; Freour, Sylvain; Jacquemin, Frederic; Casari, Pascal

2013-12-01

Environmental concern has resulted in a renewed interest in bio-based materials. Among them, plant fibres are perceived as an environmentally friendly substitute to glass fibres for the reinforcement of composites, particularly in automotive engineering. Due to their wide availability, low cost, low density, high-specific mechanical properties and eco-friendly image, they are increasingly being employed as reinforcements in polymer matrix composites. Indeed, their complex microstructure as a composite material makes plant fibre a really interesting and challenging subject to study. Research subjects about such fibres are abundant because there are always some issues to prevent their use at large scale (poor adhesion, variability, low thermal resistance, hydrophilic behavior). The choice of natural fibres rather than glass fibres as filler yields a change of the final properties of the composite. One of the most relevant differences between the two kinds of fibre is their response to humidity. Actually, glass fibres are considered as hydrophobic whereas plant fibres have a pronounced hydrophilic behavior. Composite materials are often submitted to variable climatic conditions during their lifetime, including unsteady hygroscopic conditions. However, in humid conditions, strong hydrophilic behaviour of such reinforcing fibres leads to high level of moisture absorption in wet environments. This results in the structural modification of the fibres and an evolution of their mechanical properties together with the composites in which they are fitted in. Thereby, the understanding of these moisture absorption mechanisms as well as the influence of water on the final properties of these fibres and their composites is of great interest to get a better control of such new biomaterials. This is the topic of this review paper.

Short term (14 days) consumption of insoluble wheat bran fibre-containing breakfast cereals improves subjective digestive feelings, general wellbeing and bowel function in a dose dependent manner.

Science.gov (United States)

Lawton, Clare L; Walton, Jenny; Hoyland, Alexa; Howarth, Elaine; Allan, Peter; Chesters, David; Dye, Louise

2013-04-22

This study investigated whether increasing insoluble (predominantly wheat bran) fibre over 14 days improves subjective digestive feelings, general wellbeing and bowel function. A single centre, multi-site, open, within subjects design with a 14 day non-intervention (baseline) monitoring period followed by a 14 day fibre consumption (intervention) period was performed. 153 low fibre consumers (breakfast cereal containing at least 5.4 g fibre (3.5 g from wheat bran) for 14 days and completed a daily symptom diary. Significant improvements were demonstrated in subjective perception of bowel function (e.g., ease of defecation) and digestive feelings (bloating, constipation, feeling sluggish and digestive discomfort). Significant improvements were also found in subjective perception of general wellbeing (feeling less fat, more mentally alert, slim, happy and energetic whilst experiencing less stress, mental and physical tiredness, difficulty concentrating and fewer headaches). In general, improvements in study outcomes increased with increasing cereal/fibre consumption. However, consuming an additional minimum 5.4 g of fibre (3.5 g wheat bran) per day was shown to deliver measurable and significant benefits for digestive health, comfort and wellbeing. Encouraging consumption of relatively small amounts of wheat bran could also provide an effective method of increasing overall fibre consumption.

Comparison the physicochemical properties of bunch press fibre cellulose and cyclone fibre cellulose of waste from industry Crude Palm Oil (CPO

Directory of Open Access Journals (Sweden)

Irfan Gustian

2013-10-01

Full Text Available Normal 0 false false false EN-US X-NONE X-NONE Study on comparison the physicochemical properties of bunch press fibre cellulose (Bpfc and cyclone fibre cellulose (Cfc wastes from industry Crude Palm oil (CPO have been performed. The physicochemical properties both of celluloses have been done such as the average degree of polymerization (DP, solubility properties, functional group analysis, thermal properties and X-ray diffraction patterns. The average degrees of polymerization (DP have been obtained 2195 and 567 for Bpfc and Cfc. Bunch press fibre cellulose and cyclone fibre cellulose were soluble in cupriethylenediamine (CED. FT-IR analysis showed the same pattern of spectrum but different intensities. Thermal stability of bunch press fibre cellulose and cyclone fibre cellulose remains stable up to a temperature of 250 °C. Glass transition bunch press fibre cellulose greater than the glass transition cyclone fibre cellulose and X-ray diffraction pattern shows the same pattern and intensity varies.

Natural Pineapple Leaf Fibre Extraction On Josapine And Morris

Directory of Open Access Journals (Sweden)

Mazalan Muhammad Firdaus

2017-01-01

Full Text Available The pineapple’s leaf plant contains approximately 2.5% to 3.5% of strong white silky fibres. These fibres are useful and can be extracted from the leaves. There are a few ways to extract the fibre such as hand scrapping and by extraction machine. The objective of this research is to study the quality of fibre extraction by using different age of pineapple leaf. Next, the study aims to compare the quality of Josapine and Morris pineapple leaf with tensile test. Fibre yield percentage are calculated to determine which type of pineapple leaf produce high production of dry fibre. The mechanical properties of the fibres are analysed by Tensile Test under American Standard Testing Methods (ASTM C1577-03 and Scanning Electron Microscope (SEM. The result of the fibre yield percentage show the Josapine type on 12 month ages are the highest value fibre yield percentage which is 7.89%. Based on fibre yield percentages, it showed the Josapine type produce better dry fibre production compare to Morris type. Based on mechanical test, it showed Josapine type on 12 months ages are the strongest fibre compare to Morris type since it can withstand on 67.6 N of load.

Positional short-range order in the nematic phase of n BABAs

Science.gov (United States)

Usha Deniz, K.; Pepy, G.; Parette, G.; Keller, P.

1991-10-01

The positional short-range order, SRO ⊥, perpendicular to the nematic director n̂ has been studied in the fibre-type nematics, nBABAs, by neutron diffraction. SRO ⊥ is found to be dependent on other types of nematic short-range order but not on the orientational long-range order.

Thermal Conductivity of Structural Glass/Fibre Epoxy Composite as a Function of Fibre Orientation

CERN Document Server

Cugnet, D; Kuijper, A; Parma, Vittorio; Vandoni, Giovanna

2002-01-01

The LHC, the new superconducting particle accelerator presently under construction at CERN, makes use of some 1200 dipole magnets for orbit bending and 500 quadrupole magnets for focusing/defocusing of the circulating high-energy proton beams. Two or three column-type support posts sustain each cryomagnet. The choice of a convenient material for these supports is critical, because of the required high positioning accuracy of the magnets in their cryostats and stringent thermal budget requirements imposed by the LHC cryogenic system. A glass-fibre/epoxy resin composite has been chosen for its good combination of high stiffness and low thermal conductivity over the 2-293 K temperature range. Plies of long glass-fibres are stacked optimally yielding the best mechanical behaviour. However, heat leaks from the supports are influenced by the thermal characteristics of the composite, which in turn depend on the orientation of the fibres. To study the dependence of the thermal conductivity on fibre's orientation, we ...

Theorem of comparative sensitivity of fibre sensors

Science.gov (United States)

Belovolov, M. I.; Paramonov, V. M.; Belovolov, M. M.

2017-12-01

We report an analysis of sensitivity of fibre sensors of physical quantities based on different types of interferometers. We formulate and prove the following theorem: under the time-dependent external physical perturbations at nonzero frequencies (i.e., except the static and low-frequency ones) on the sensitive arms of an interferometer in the form of multiturn elements (coils), there exist such lengths L of the measuring arms of the fibre interferometers at which the sensitivity of sensors based on the Sagnac fibre interferometers can be comparable with the sensitivity of sensors based on Michelson, Mach - Zehnder, or Fabry - Perot fibre interferometers, as well as exceed it under similar other conditions (similar-type perturbations, similar arm lengths and single-mode fibre types). The consequences that follow from the theorem, important for practical implementation of arrays of fibre sensors for measurement purposes and the devices with stable metrological properties, are discussed.

Two functionally different muscle fibre types in some salps?

Directory of Open Access Journals (Sweden)

Q. Bone

1998-12-01

Full Text Available This paper describes the structure and operation of the fibres in the locomotor muscle bands of several salp species. In many species, for example Thalia democratica or Pegea confoederata, all the muscle fibres of the locomotor muscle bands are similar in width and structure. In others, for example Salpa fusiformis and S. maxima, although fibre structure is similar, the marginal fibres edging the bands may be some 3-4 times the width of those in the centre of the band. In Ihlea punctata, not only is there a more striking difference in width between the marginal and central fibres of the bands, but also the two differ in structure. The marginal fibres are up to 10 times the width of the central fibres and the two differ in myofibrillar and mitochondrial content. Intracellular recordings from the fibres show that the normally compound spike potentials do not overshoot resting potentials (up to -70 mV, and are decremental. The two types of fibre may be separately activated. It is suggested that in Ihlea punctata, the wide marginal fibres may be involved in slow swimming, the central narrow fibres in `escape´ swimming.

Neuromuscular organization of avian flight muscle: architecture of single muscle fibres in muscle units of the pectoralis (pars thoracicus) of pigeon (Columba livia)

Science.gov (United States)

Sokoloff, A. J.

1999-01-01

The M. pectoralis (pars thoracicus) of pigeons (Columba livia) is comprised of short muscle fibres that do not extend from muscle origin to insertion but overlap 'in-series'. Individual pectoralis motor units are limited in territory to a portion of muscle length and are comprised of either fast twitch, oxidative and glycolytic fibres (FOG) or fast twitch and glycolytic fibres (FG). FOG fibres make up 88 to 90% of the total muscle population and have a mean diameter one-half of that of the relatively large FG fibres. Here we report on the organization of individual fibres identified in six muscle units depleted of glycogen, three comprised of FOG fibres and three comprised of FG fibres. For each motor unit, fibre counts revealed unequal numbers of depleted fibres in different unit cross-sections. We traced individual fibres in one unit comprised of FOG fibres and a second comprised of FG fibres. Six fibres from a FOG unit (total length 15.45 mm) ranged from 10.11 to 11.82 mm in length and averaged (± s.d.) 10.74 ± 0.79 mm. All originated bluntly (en mass) from a fascicle near the proximal end of the muscle unit and all terminated intramuscularly. Five of these ended in a taper and one ended bluntly. Fibres coursed on average for 70% of the muscle unit length. Six fibres from a FG unit (total length 34.76 mm) ranged from 8.97 to 18.38 mm in length and averaged 15.32 ± 3.75 mm. All originated bluntly and terminated intramuscularly; one of these ended in a taper and five ended bluntly. Fibres coursed on average for 44% of the muscle unit length. Because fibres of individual muscle units do not extend the whole muscle unit territory, the effective cross-sectional area changes along the motor unit length. These non-uniformities in the distribution of fibres within a muscle unit emphasize that the functional interactions within and between motor units are complex.

The effect of fibre layering pattern in resisting bending loads of natural fibre-based hybrid composite materials

Directory of Open Access Journals (Sweden)

Jusoh Muhamad Shahirul Mat

2016-01-01

Full Text Available The effect of fibre layering pattern and hybridization on the flexural properties of composite hybrid laminates between natural fibres of basalt, jute and flax with synthetic fibre of E-glass reinforced epoxy have been investigated experimentally. Results showed that the effect fibre layering pattern was highly significant on the flexural strength and modulus, which were strongly dependent on the hybrid configuration between sandwich-like (SL and intercalation (IC sequence of fibre layers. In addition, specific modulus based on the variation densities of the hybrid laminates was used to discover the best combination either basalt, jute or flax with E-glass exhibits superior properties concerning on the strength to weight-ratio. Generally, SL sequence of glass/basalt exhibited superior strength and stiffness compared with glass/jute and glass/flax in resisting bending loads. In terms of hybridization effect, glass/jute was found to be the best combination with E-glass compared to the rest of natural fibres investigated in the present study. Hence, the proper stacking sequences and material selection are among predominant factors that influence on mechanical properties and very crucial in designing composite hybrid system to meet the desired requirements.

Sensitivity of a fibre scattered-light interferometer to external phase perturbations in an optical fibre

Energy Technology Data Exchange (ETDEWEB)

Alekseev, A E; Potapov, V T [V.A.Kotel' nikov Institute of Radio Engineering and Electronics, Russian Academy of Sciences, Fryazino Branch, Fryazino, Moscow region (Russian Federation); Gorshkov, B G [OOO ' Petrofaiber' , Russia, Tula region, Novomoskovsk (Russian Federation)

2015-10-31

Sensitivity of a fibre scattered-light interferometer to external phase perturbations is studied for the first time. An expression is derived for an average power of a useful signal at the interferometer output under external harmonic perturbations in a signal fibre of the interferometer. It is shown that the maximum sensitivity of the scattered-light interferometer depends on the dispersion of the interferogram intensity. An average signal-to-noise ratio is determined theoretically and experimentally at the output of the interferometer at different amplitudes of external perturbations. Using the measured dependences of the signal-to-noise ratio, the threshold sensitivity of the fibre scattered-light interferometer to external phase perturbations is found. The results obtained can be used to optimise characteristics of optical time-domain reflectometers and to design individual phase-sensitive fibre-optic sensors. (laser applications and other topics in quantum electronics)

Geometrical Characterisation of Individual Fibres From X-Ray Tomograms

DEFF Research Database (Denmark)

Emerson, Monica Jane; Dahl, Vedrana Andersen; Mikkelsen, Lars Pilgaard

2017-01-01

We have developed an image analysis pipeline1 that can extract individual fibre tracksfrom low contrast X-ray tomograms of unidirectional composites with high fibre volumefraction. Measuring individual fibre tracks opens up the possibility of modelling thisempirical data in a statistical manner....... Thus, allowing to analyse the spatial distributionsof the parameters characterising the orientation and curvature of these individual fibres,which can also provide insights on the interactions amongst the individual fibres.Finite element models (FEMs) can be built from the extracted geometry...... to simulatethe performance of the scanned fibre structure under realistic conditions. Moreover, as-pects of the fibre architecture that inuence the macroscopic behaviour of the compositecan be quantified. Examples are 2D FEMs to predict the transverse stifiness or the quantification of fibre orientations...

Modelling of polypropylene fibre-matrix composites using finite element analysis

Directory of Open Access Journals (Sweden)

2009-01-01

Full Text Available Polypropylene (PP fibre-matrix composites previously prepared and studied experimentally were modelled using finite element analysis (FEA in this work. FEA confirmed that fibre content and composition controlled stress distribution in all-PP composites. The stress concentration at the fibre-matrix interface became greater with less fibre content. Variations in fibre composition were more significant in higher stress regions of the composites. When fibre modulus increased, the stress concentration at the fibres decreased and the shear stress at the fibre-matrix interface became more intense. The ratio between matrix modulus and fibre modulus was important, as was the interfacial stress in reducing premature interfacial failure and increasing mechanical properties. The model demonstrated that with low fibre concentration, there were insufficient fibres to distribute the applied stress. Under these conditions the matrix yielded when the applied stress reached the matrix yield stress, resulting in increased fibre axial stress. When the fibre content was high, there was matrix depletion and stress transfer was inefficient. The predictions of the FEA model were consistent with experimental and published data.

Current status of natural fibres

CSIR Research Space (South Africa)

Anandjiwala, RD

2006-12-01

Full Text Available Fiber Selection Conference, 17-19 May 1999, Greenville, SC, USA. 16. Sankari, H.S. 2000. Comparison of bast fibre yield and mechanical fibre properties of hemp (Cannabis sativa L.) cultivars. Industrial Crops and Products (11) 1: 73-84. 17. W...

Hybrid RSOA and fibre raman amplified long reach feeder link for WiMAX-on-fibre

DEFF Research Database (Denmark)

Amaya Fernández, Ferney Orlando; Martinez, Javier; Yu, Xianbin

2009-01-01

A distributed fibre Raman amplified long reach optical access feeder link using a reflective semiconductor optical amplifier in the remote base station is experimentally demonstrated for supporting WiMAXover- fibre transmission. The measured values for the error vector magnitude for quadrature...

Continuous jute fibre reinforced laminated paper composite

Indian Academy of Sciences (India)

Jute fibre; laminated paper composite; plastic bag pollution. Abstract. Plastic bags create a serious environmental problem. The proposed jute fibre reinforced laminated paper composite and reinforcement-fibre free paper laminate may help to combat the war against this pollutant to certain extent. The paper laminate ...

Multicore fibre photonic lanterns for precision radial velocity Science

Science.gov (United States)

Gris-Sánchez, Itandehui; Haynes, Dionne M.; Ehrlich, Katjana; Haynes, Roger; Birks, Tim A.

2018-04-01

Incomplete fibre scrambling and fibre modal noise can degrade high-precision spectroscopic applications (typically high spectral resolution and high signal to noise). For example, it can be the dominating error source for exoplanet finding spectrographs, limiting the maximum measurement precision possible with such facilities. This limitation is exacerbated in the next generation of infra-red based systems, as the number of modes supported by the fibre scales inversely with the wavelength squared and more modes typically equates to better scrambling. Substantial effort has been made by major research groups in this area to improve the fibre link performance by employing non-circular fibres, double scramblers, fibre shakers, and fibre stretchers. We present an original design of a multicore fibre (MCF) terminated with multimode photonic lantern ports. It is designed to act as a relay fibre with the coupling efficiency of a multimode fibre (MMF), modal stability similar to a single-mode fibre and low loss in a wide range of wavelengths (380 nm to 860 nm). It provides phase and amplitude scrambling to achieve a stable near field and far-field output illumination pattern despite input coupling variations, and low modal noise for increased stability for high signal-to-noise applications such as precision radial velocity (PRV) science. Preliminary results are presented for a 511-core MCF and compared with current state of the art octagonal fibre.

REINFORCING FIBRES AS PART OF TECHNOLOGY OF CONCRETES

Directory of Open Access Journals (Sweden)

Zhukov Aleksey Dmitrievich

2012-07-01

It was identified that the basalt fibre consumption rate influences both the strength and the density of products made of cellular concrete. The length of the basalt fibre impacts the strength of products. A nomogram was developed to identify the consumption rate of the basalt fibre driven by the strength of products and the Portland cement consumption rate. The authors also studied the influence of the consumption rate of Portland cement and basalt fibre onto the structural quality ratio of the foamed fibre concrete.

Reinforcing of Cement Composites by Estabragh Fibres

Science.gov (United States)

Merati, A. A.

2014-04-01

The influence of Estabragh fibres has been studied to improve the performance characteristics of the reinforced cement composites. The concrete shrinkage was evaluated by counting the number of cracks and measuring the width of cracks on the surface of concrete specimens. Although, the Estabragh fibres lose their strength in an alkali environment of cement composites, but, the ability of Estabragh fibres to bridge on the micro cracks in the concrete matrix causes to decrease the width of the cracks on the surface of the concrete samples in comparison with the plain concrete. However, considering the mechanical properties of specimens such as bending strength and impact resistance, the specimens with 0.25 % of Estabragh fibre performed better in all respects compared to the physical and mechanical properties of reinforced cement composite of concrete. Consequently, by adding 0.25 % of Estabragh fibres to the cement composite of concrete, a remarkable improvement in physical and mechanical properties of fibre-containing cement composite is achieved.

Dietary fibre: new frontiers for food and health

National Research Council Canada - National Science Library

Kamp, J. W. van der

2010-01-01

... papers of the Dietary fibre analysis workshop and the HEALTHGRAIN Symposium Cereal grain fibre and health , both held in conjunction with DF09. This book is titled Dietary fibre- new frontiers for food and health . With the adoption - after decades of debate - of almost identical definitions of dietary fibre by Codex Alimentarius and the European Un...

Process monitoring of fibre reinforced composites using optical fibre sensors

Energy Technology Data Exchange (ETDEWEB)

Fernando, G.F.; Degamber, B.

2006-04-15

The deployment of optical fibre based sensor systems for process monitoring of advanced fibre reinforced organic matrix composites is reviewed. The focus is on thermosetting resins and the various optical and spectroscopy-based techniques that can be used to monitor the processing of these materials. Following brief consideration of the manufacturing methods commonly used in the production of thermoset based composites, a discussion is presented on sensor systems that can be used to facilitate real-time chemical process monitoring. Although the focus is on thermosets, the techniques described can be adapted for chemical monitoring of organic species in general. (author)

Short Term (14 Days Consumption of Insoluble Wheat Bran Fibre-Containing Breakfast Cereals Improves Subjective Digestive Feelings, General Wellbeing and Bowel Function in a Dose Dependent Manner

Directory of Open Access Journals (Sweden)

Louise Dye

2013-04-01

Full Text Available This study investigated whether increasing insoluble (predominantly wheat bran fibre over 14 days improves subjective digestive feelings, general wellbeing and bowel function. A single centre, multi-site, open, within subjects design with a 14 day non-intervention (baseline monitoring period followed by a 14 day fibre consumption (intervention period was performed. 153 low fibre consumers (<15 g/day AOAC 985.29 completed a daily symptom diary for 14 days after which they consumed one bowl of ready-to-eat breakfast cereal containing at least 5.4 g fibre (3.5 g from wheat bran for 14 days and completed a daily symptom diary. Significant improvements were demonstrated in subjective perception of bowel function (e.g., ease of defecation and digestive feelings (bloating, constipation, feeling sluggish and digestive discomfort. Significant improvements were also found in subjective perception of general wellbeing (feeling less fat, more mentally alert, slim, happy and energetic whilst experiencing less stress, mental and physical tiredness, difficulty concentrating and fewer headaches. In general, improvements in study outcomes increased with increasing cereal/fibre consumption. However, consuming an additional minimum 5.4 g of fibre (3.5 g wheat bran per day was shown to deliver measurable and significant benefits for digestive health, comfort and wellbeing. Encouraging consumption of relatively small amounts of wheat bran could also provide an effective method of increasing overall fibre consumption.

Short Term (14 Days) Consumption of Insoluble Wheat Bran Fibre-Containing Breakfast Cereals Improves Subjective Digestive Feelings, General Wellbeing and Bowel Function in a Dose Dependent Manner

Science.gov (United States)

Lawton, Clare L.; Walton, Jenny; Hoyland, Alexa; Howarth, Elaine; Allan, Peter; Chesters, David; Dye, Louise

2013-01-01

This study investigated whether increasing insoluble (predominantly wheat bran) fibre over 14 days improves subjective digestive feelings, general wellbeing and bowel function. A single centre, multi-site, open, within subjects design with a 14 day non-intervention (baseline) monitoring period followed by a 14 day fibre consumption (intervention) period was performed. 153 low fibre consumers (<15 g/day AOAC 985.29) completed a daily symptom diary for 14 days after which they consumed one bowl of ready-to-eat breakfast cereal containing at least 5.4 g fibre (3.5 g from wheat bran) for 14 days and completed a daily symptom diary. Significant improvements were demonstrated in subjective perception of bowel function (e.g., ease of defecation) and digestive feelings (bloating, constipation, feeling sluggish and digestive discomfort). Significant improvements were also found in subjective perception of general wellbeing (feeling less fat, more mentally alert, slim, happy and energetic whilst experiencing less stress, mental and physical tiredness, difficulty concentrating and fewer headaches). In general, improvements in study outcomes increased with increasing cereal/fibre consumption. However, consuming an additional minimum 5.4 g of fibre (3.5 g wheat bran) per day was shown to deliver measurable and significant benefits for digestive health, comfort and wellbeing. Encouraging consumption of relatively small amounts of wheat bran could also provide an effective method of increasing overall fibre consumption. PMID:23609776

Study on the Sensing Coating of the Optical Fibre CO2 Sensor

Directory of Open Access Journals (Sweden)

Karol Wysokiński

2015-12-01

Full Text Available Optical fibre carbon dioxide (CO2 sensors are reported in this article. The principle of operation of the sensors relies on the absorption of light transmitted through the fibre by a silica gel coating containing active dyes, including methyl red, thymol blue and phenol red. Stability of the sensor has been investigated for the first time for an absorption based CO2 optical fiber sensor. Influence of the silica gel coating thickness on the sensitivity and response time has also been studied. The impact of temperature and humidity on the sensor performance has been examined too. Response times of reported sensors are very short and reach 2–3 s, whereas the sensitivity of the sensor ranges from 3 to 10 for different coating thicknesses. Reported parameters make the sensor suitable for indoor and industrial use.

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.

Differential modal delay measurements in a graded-index multimode fibre waveguide, using a single-mode fibre pro mode selection

International Nuclear Information System (INIS)

Sunak, H.R.D.; Soares, S.M.

1981-01-01

Differential model delay (DMD) measurements in graded-index multimode optical fibre waveguides, which are very promising for many types of communication system were carried out. These DMD measurements give a direct indication of the deviation of the refractive index profile, from the optimum value, at a given wavelength. For the first time, by using a single-mode fibre, a few guided modes in the graded-index fibre were selected, in two different ways: launching a few modes at the input end or selecting a few modes at the output end. By doing so important features of propagation in the fibre were revealed, especially the intermodal coupling that may exist. The importance of this determination of intermodal coupling or mode mixing, particularly when many fibres are joined together in a link, and the merits of DMD measurements in general and their importance for the production of high bandwidth graded-index fibres are discussed. (Author) [pt

Dietary fibre in foods: a review

OpenAIRE

Dhingra, Devinder; Michael, Mona; Rajput, Hradesh; Patil, R. T.

2011-01-01

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 li...

Fibre Bragg Grating Sensor Signal Post-processing Algorithm: Crack Growth Monitoring in Fibre Reinforced Plastic Structures

DEFF Research Database (Denmark)

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

2016-01-01

A novel method to assess a crack growing/damage event in fibre reinforced plastic, using conventional single mode Fibre Bragg Grating sensors embedded in the host material is presented in this article. Three different damage mechanisms that can change the sensor output, longitudinal strain εxx......, transversal stress σyy;zz, and non-uniform strain εxx(xx), were identified. These damage mechanisms were identified during the experimental testing and linked with the sensor output using a digital image correlation technique. A dedicated algorithm to extract information from the reflected spectrum...... that enables crack detection was developed. Double Cantilever Beams specimens made with glass fibre and bonded with structural adhesive, were instrumented with a Fibre Bragg Grating array embedded in the host material, and tested using an experimental fracture procedure. This method was successfully validated...

Adaptive functional specialisation of architectural design and fibre type characteristics in agonist shoulder flexor muscles of the llama, Lama glama.

Science.gov (United States)

Graziotti, Guillermo H; Chamizo, Verónica E; Ríos, Clara; Acevedo, Luz M; Rodríguez-Menéndez, J M; Victorica, C; Rivero, José-Luis L

2012-08-01

Like other camelids, llamas (Lama glama) have the natural ability to pace (moving ipsilateral limbs in near synchronicity). But unlike the Old World camelids (bactrian and dromedary camels), they are well adapted for pacing at slower or moderate speeds in high-altitude habitats, having been described as good climbers and used as pack animals for centuries. In order to gain insight into skeletal muscle design and to ascertain its relationship with the llama's characteristic locomotor behaviour, this study examined the correspondence between architecture and fibre types in two agonist muscles involved in shoulder flexion (M. teres major - TM and M. deltoideus, pars scapularis - DS and pars acromialis - DA). Architectural properties were found to be correlated with fibre-type characteristics both in DS (long fibres, low pinnation angle, fast-glycolytic fibre phenotype with abundant IIB fibres, small fibre size, reduced number of capillaries per fibre and low oxidative capacity) and in DA (short fibres, high pinnation angle, slow-oxidative fibre phenotype with numerous type I fibres, very sparse IIB fibres, and larger fibre size, abundant capillaries and high oxidative capacity). This correlation suggests a clear division of labour within the M. deltoideus of the llama, DS being involved in rapid flexion of the shoulder joint during the swing phase of the gait, and DA in joint stabilisation during the stance phase. However, the architectural design of the TM muscle (longer fibres and lower fibre pinnation angle) was not strictly matched with its fibre-type characteristics (very similar to those of the postural DA muscle). This unusual design suggests a dual function of the TM muscle both in active flexion of the shoulder and in passive support of the limb during the stance phase, pulling the forelimb to the trunk. This functional specialisation seems to be well suited to a quadruped species that needs to increase ipsilateral stability of the limb during the support

Adaptive functional specialisation of architectural design and fibre type characteristics in agonist shoulder flexor muscles of the llama, Lama glama

Science.gov (United States)

Graziotti, Guillermo H; Chamizo, Verónica E; Ríos, Clara; Acevedo, Luz M; Rodríguez-Menéndez, J M; Victorica, C; Rivero, José-Luis L

2012-01-01

Like other camelids, llamas (Lama glama) have the natural ability to pace (moving ipsilateral limbs in near synchronicity). But unlike the Old World camelids (bactrian and dromedary camels), they are well adapted for pacing at slower or moderate speeds in high-altitude habitats, having been described as good climbers and used as pack animals for centuries. In order to gain insight into skeletal muscle design and to ascertain its relationship with the llama’s characteristic locomotor behaviour, this study examined the correspondence between architecture and fibre types in two agonist muscles involved in shoulder flexion (M. teres major – TM and M. deltoideus, pars scapularis – DS and pars acromialis – DA). Architectural properties were found to be correlated with fibre-type characteristics both in DS (long fibres, low pinnation angle, fast-glycolytic fibre phenotype with abundant IIB fibres, small fibre size, reduced number of capillaries per fibre and low oxidative capacity) and in DA (short fibres, high pinnation angle, slow-oxidative fibre phenotype with numerous type I fibres, very sparse IIB fibres, and larger fibre size, abundant capillaries and high oxidative capacity). This correlation suggests a clear division of labour within the M. deltoideus of the llama, DS being involved in rapid flexion of the shoulder joint during the swing phase of the gait, and DA in joint stabilisation during the stance phase. However, the architectural design of the TM muscle (longer fibres and lower fibre pinnation angle) was not strictly matched with its fibre-type characteristics (very similar to those of the postural DA muscle). This unusual design suggests a dual function of the TM muscle both in active flexion of the shoulder and in passive support of the limb during the stance phase, pulling the forelimb to the trunk. This functional specialisation seems to be well suited to a quadruped species that needs to increase ipsilateral stability of the limb during the

Fabrication and oxidation resistance of titanium carbide-coated carbon fibres by reacting titanium hydride with carbon fibres in molten salts

International Nuclear Information System (INIS)

Dong, Z.J.; Li, X.K.; Yuan, G.M.; Cong, Y.; Li, N.; Jiang, Z.Y.; Hu, Z.J.

2009-01-01

Using carbon fibres and titanium hydride as a reactive carbon source and a metal source, respectively, a protective titanium carbide (TiC) coating was formed on carbon fibres in molten salts, composed of LiCl-KCl-KF, at 750-950 o C. The structure and morphology of the TiC coatings were characterised by X-ray diffraction and scanning electron microscopy, respectively. The oxidation resistance of the TiC-coated carbon fibres was measured by thermogravimetric analysis. The results reveal that control of the coating thickness is very important for improvement of the oxidation resistance of TiC-coated carbon fibres. The oxidative weight loss initiation temperature for the TiC-coated carbon fibres increases significantly when an appropriate coating thickness is used. However, thicker coatings lead to a decrease of the carbon fibres' weight loss initiation temperature due to the formation of cracks in the coating. The TiC coating thickness on carbon fibres can be controlled by adjusting the reaction temperature and time of the molten salt synthesis.

Fibre inflation and α-attractors

Energy Technology Data Exchange (ETDEWEB)

Kallosh, Renata; Linde, Andrei [Stanford Univ., Stanford, CA (United States). Stanford Inst. for Theoretical Physics and Dept. of Physics; Leiden Univ. (Netherlands). Lorentz Inst. for Theoretical Physics; Roest, Diederik [Groningen Univ. (Netherlands). Van Swinderen Inst. for Particle Physics and Gravity; Westphal, Alexander [DESY, Hamburg (Germany). Theory Group; Yamada, Yusuke [Stanford Univ., Stanford, CA (United States). Stanford Inst. for Theoretical Physics and Dept. of Physics

2017-07-15

Fibre inflation is a specific string theory construction based on the Large Volume Scenario that produces an inflationary plateau. We outline its relation to α-attractor models for inflation, with the cosmological sector originating from certain string theory corrections leading to α=2 and α=1/2. Above a certain field range, the steepening effect of higher-order corrections leads first to the breakdown of single-field slow-roll and after that to the onset of 2-field dynamics: the overall volume of the extra dimensions starts to participate in the effective dynamics. Finally, we propose effective supergravity models of fibre inflation based on an D3 uplift term with a nilpotent superfield. Specific moduli dependent D3 induced geometries lead to cosmological fibre models but have in addition a de Sitter minimum exit. These supergravity models motivated by fibre inflation are relatively simple, stabilize the axions and disentangle the Hubble parameter from supersymmetry breaking.

Fibre inflation and α-attractors

Science.gov (United States)

Kallosh, Renata; Linde, Andrei; Roest, Diederik; Westphal, Alexander; Yamada, Yusuke

2018-02-01

Fibre inflation is a specific string theory construction based on the Large Volume Scenario that produces an inflationary plateau. We outline its relation to α-attractor models for inflation, with the cosmological sector originating from certain string theory corrections leading to α = 2 and α = 1/2. Above a certain field range, the steepening effect of higher-order corrections leads first to the breakdown of single-field slow-roll and after that to the onset of 2-field dynamics: the overall volume of the extra dimensions starts to participate in the effective dynamics. Finally, we propose effective supergravity models of fibre inflation based on an \\overline{D3} uplift term with a nilpotent superfield. Specific moduli dependent \\overline{D3} induced geometries lead to cosmological fibre models but have in addition a de Sitter minimum exit. These supergravity models motivated by fibre inflation are relatively simple, stabilize the axions and disentangle the Hubble parameter from supersymmetry breaking.

Electrical stimulation to the trigeminal proprioceptive fibres that innervate the mechanoreceptors in Müller's muscle induces involuntary reflex contraction of the frontalis muscles.

Science.gov (United States)

Matsuo, Kiyoshi; Osada, Yoshiro; Ban, Ryokuya

2013-02-01

The levator and frontalis muscles lack interior muscle spindles, despite consisting of slow-twitch fibres that involuntarily sustain eyelid-opening and eyebrow-raising against gravity. To compensate for this anatomical defect, this study hypothetically proposes that initial voluntary contraction of the levator fast-twitch muscle fibres stretches the mechanoreceptors in Müller's muscle and evokes proprioception, which continuously induces reflex contraction of slow-twitch fibres of the levator and frontalis muscles. This study sought to determine whether unilateral transcutaneous electrical stimulation to the trigeminal proprioceptive fibres that innervate the mechanoreceptors in Müller's muscle could induce electromyographic responses in the frontalis muscles, with monitoring responses in the orbicularis oculi muscles. The study population included 27 normal subjects and 23 subjects with aponeurotic blepharoptosis, who displayed persistently raised eyebrows on primary gaze and light eyelid closure. The stimulation induced a short-latency response in the ipsilateral frontalis muscle of all subjects and long-latency responses in the bilateral frontalis muscles of normal subjects. However, it did not induce long-latency responses in the bilateral frontalis muscles of subjects with aponeurotic blepharoptosis. The orbicularis oculi muscles showed R1 and/or R2 responses. The stimulation might reach not only the proprioceptive fibres, but also other sensory fibres related to the blink or corneal reflex. The experimental system can provoke a monosynaptic short-latency response in the ipsilateral frontalis muscle, probably through the mesencephalic trigeminal proprioceptive neuron and the frontalis motor neuron, and polysynaptic long-latency responses in the bilateral frontalis muscles through an unknown pathway. The latter neural circuit appeared to be engaged by the circumstances of aponeurotic blepharoptosis.

Failure phenomena in fibre-reinforced composites. Part 6: a finite element study of stress concentrations in unidirectional carbon fibre-reinforced epoxy composites

NARCIS (Netherlands)

van den Heuvel, P.W.J.; Goutianos, S.; Young, R.J.; Peijs, A.A.J.M.

2004-01-01

A three-dimensional (3-D) finite element (FE) analysis of the stress situation around a fibre break in a unidirectional carbon fibre-reinforced epoxy composite has been performed. Two cases were considered: (i) good fibre/matrix adhesion and (ii) fibre/matrix debonding. In the case of good adhesion,

Analysing the nanoporous structure of aramid fibres

DEFF Research Database (Denmark)

Pauw, Brian Richard; Vigild, Martin Etchells; Mortensen, Kell

2010-01-01

After consideration of the applicability of classical methods, a novel analysis method for the characterization of fibre void structures is presented, capable of fitting the entire anisotropic two-dimensional scattering pattern to a model of perfectly aligned, polydisperse ellipsoids. It is tested...... for validity against the computed scattering pattern for a simulated nanostructure, after which it is used to fit the scattering from the void structure of commercially available heat-treated poly(p-phenylene terephtalamide) fibre and its as-spun precursor fibre. The application shows a reasonable fit...... scattering on the scattering pattern. The fit to the scattering pattern of as-spun aramid fibre is improved by the introduction of the large scatterers, while the fit to the scattering pattern obtained from the heat-treated fibre improves when an orientation distribution is taken into account...

The renaissance and bright future of fibre lasers

International Nuclear Information System (INIS)

Tuennermann, A; Schreiber, T; Roeser, F; Liem, A; Hoefer, S; Zellmer, H; Nolte, S; Limpert, J

2005-01-01

The first rare-earth-doped fibre lasers were operated in the early 1960s and produced a few milliwatts at a wavelength around 1 μm. For the next several decades, fibre lasers were little more than a low-power laboratory curiosity. Recently, however, fibre lasers have entered the realm of kilowatt powers with diffraction-limited beam quality. In this paper we review the reasons for this power evolution. Beyond this, we will discuss how the next generation of fibres, so-called photonic crystal fibres, enable upward power scaling and therefore open up the avenue to new performance levels of solid-state lasers

Fatigue mechanisms in unidirectional glass-fibre-reinforced polypropylene

DEFF Research Database (Denmark)

Gamstedt, E.K.; Berglund, L.A.; Peijs, T.

1999-01-01

Polypropylene (PP) and polypropylene modified with maleic anhydride (MA-PP) reinforced by continuous longitudinal glass fibres have been investigated. The most prominent effect of the modification with maleic anhydride in the composite is a stronger fibre/matrix interface. The effects of interfac......Polypropylene (PP) and polypropylene modified with maleic anhydride (MA-PP) reinforced by continuous longitudinal glass fibres have been investigated. The most prominent effect of the modification with maleic anhydride in the composite is a stronger fibre/matrix interface. The effects...... of interfacial strength on fatigue performance and on the underlying micromechanisms have been studied for these composite systems. Tension-tension fatigue tests (R = 0.1) were carried out on 0 degrees glass-fibre/PP and glass-fibre/ MA-PP coupons. The macroscopic fatigue behaviour was characterized in terms...

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.

Mechanical characterisation of hybrid composite laminates based on basalt fibres in combination with flax, hemp and glass fibres manufactured by vacuum infusion

International Nuclear Information System (INIS)

Petrucci, R.; Santulli, C.; Puglia, D.; Sarasini, F.; Torre, L.; Kenny, J.M.

2013-01-01

Highlights: ► For the first time, hybrid laminates with three different fibres were produced. ► Concerns are confirmed on the brittleness of hybrid laminates with basalt fibre core. ► An optimal configuration (FHB) for flexural properties was singled out. ► Differences between tensile and flexural properties of hybrids were identified. ► In general, the specific mechanical properties of the hybrids are quite high. - Abstract: This work concerns the production by vacuum infusion and the comparison of the properties of different hybrid composite laminates, based on basalt fibre composites as the inner core, and using also glass, flax and hemp fibre laminates to produce symmetrical configurations, all of them with a 21–23% fibre volume, in an epoxy resin. The laminates have been subjected to tensile, three-point flexural and interlaminar shear strength tests and their fracture surfaces have been characterised by scanning electron microscopy. The mechanical performance of all the hybrid laminates appears superior to pure hemp and flax fibre reinforced laminates and inferior to basalt fibre laminates. Among the hybrids, the best properties are offered by those obtained by adding glass and flax to basalt fibre reinforced laminates. Scanning electron microscopy (SEM) observation of hybrid laminates showed the diffuse presence of fibre pull-out in hemp and flax fibre reinforced layers and a general trend of brittle failure

Glass fibre sensors for medical applications - fibre-optical dosimeter system. Cooperation project 1991-1994. Final report

International Nuclear Information System (INIS)

1996-01-01

The final report summarizes the results of a cooperation project on the applications of fibre-optical sensors in medical technology. The FADOS dosimeter system is presented which comprises an implantable glass fibre dosimeter. It can be applied in radiotherapy for online dose metering directly at the tumour or in the surrounding healthy tissue. The dosimeter is placed in a tissue-compatible flexible catheter tube and remains inside the body during the radiotherapy treatiment. The measuring principle is based on the effect of radiation-induced damping inside a glass fibre. (DG) [de

Human skeletal muscle: transition between fast and slow fibre types.

Science.gov (United States)

Neunhäuserer, Daniel; Zebedin, Michaela; Obermoser, Magdalena; Moser, Gerhard; Tauber, Mark; Niebauer, Josef; Resch, Herbert; Galler, Stefan

2011-05-01

Human skeletal muscles consist of different fibre types: slow fibres (slow twitch or type I) containing the myosin heavy chain isoform (MHC)-I and fast fibres (fast twitch or type II) containing MHC-IIa (type IIA) or MHC-IId (type IID). The following order of decreasing kinetics is known: type IID > type IIA > type I. This order is especially based on the kinetics of stretch activation, which is the most discriminative property among fibre types. In this study we tested if hybrid fibres containing both MHC-IIa and MHC-I (type C fibres) provide a transition in kinetics between fast (type IIA) and slow fibres (type I). Our data of stretch activation kinetics suggest that type C fibres, with different ratios of MHC-IIa and MHC-I, do not provide a continuous transition. Instead, a specialized group of slow fibres, which we called "transition fibres", seems to provide a transition. Apart of their kinetics of stretch activation, which is most close to that of type IIA, the transition fibres are characterized by large cross-sectional areas and low maximal tensions. The molecular cause for the mechanical properties of the transition fibres is unknown. It is possible that the transition fibres contain an unknown slow MHC isoform, which cannot be separated by biochemical methods. Alternatively, or in addition, isoforms of myofibrillar proteins, other than MHC, and posttranslational modifications of myofibrillar proteins could play a role regarding the characteristics of the transition fibres.

THERMOMECHANICAL PROPERTIES OF JUTE/BAGASSE HYBRID FIBRE REINFORCED EPOXY THERMOSET COMPOSITES

OpenAIRE

Sudhir Kumar Saw; Chandan Datta

2009-01-01

Natural fibres are partly replacing currently used synthetic fibres as reinforcement for polymer composites. Jute fibre bundles were high-cellulose-content modified by alkali treatment, while the bagasse fibre bundles were modified by creating quinones in the lignin portions of fibre surfaces and reacting them with furfuryl alcohol (FA) to increase their adhesiveness. The effects of different fibre bundle loading and modification of bagasse fibre surfaces in hybrid fibre reinforced epoxy comp...

Panel Board From Coconut Fibre And Pet Bottle

Science.gov (United States)

Ngadiman, Norhayati; Kaamin, Masiri; Abd. Kadir, Aslila; Sahat, Suhaila; Zaini, Aziza; Raihana Nor Zentan, Siti; Ain Ahmad, Nur; Amran, Wan Haizatul Aisyhah Wan

2018-03-01

The rate of global deforestation and its impact on the environment has led particle board manufacture to search for alternative feedstock, especially in countries where wood is less available compared to other cellulosic natural product. Based on the properties of coconut fibre and PET bottle, these two materials can be recycle as raw material for manufacture of panel board. As for this study, the coconut fibre were used as the filler and PET bottle as outer lining of the panel board. Two types of coconut fibre were used which are grinding and un-grinding coconut fibre. At first, the coconut fibre are undergoes softening, grinding, drying and sieving process, while PET bottle was cleaning, shredding, sieving before compacted using hydraulic hot press machine. There are four types of testing that been carried out which are swelling, water absorption, Modulus of Elasticity (MOE) and Modulus of Rupture (MOR). The result show the conventional board has the highest value for MOE test, so it's indicate that the conventional board is less strength from the coconut fibre board. As for water absorption test, the average water absorption of coconut fibre based panel board is less than conventional board. Overall, the coconut fibre board is better than conventional panel board because coconut fibre board are less swelling, has low water absorption, high modulus of rupture and low modulus of elasticity. Based on the finding, this coconut fibre panel board has potential as a stronger and long-lasting panel board than the conventional board in the market. Other than that, the panel also have their own aesthetic value since the recycled plastic bottle used as outer lining is colourful and giving aesthetic value.

Effects of Basalt Fibres on Mechanical Properties of Concrete

Directory of Open Access Journals (Sweden)

El-Gelani A. M.

2018-01-01

Full Text Available This paper presents the results of an experimental program carried out to investigate the effects of Basalt Fibre Reinforced Polymers (BFRP on some fundamental mechanical properties of concrete. Basalt fibres are formed by heating crushed basalt rocks and funnelling the molten basalt through a spinneret to form basalt filaments. This type of fibres have not been widely used till recently. Two commercially available chopped basalt fibres products with different aspect ratios were investigated, which are dry basalt (GeoTech Fibre and basalt pre-soaked in an epoxy resin (GeoTech Matrix .The experimental work included compression tests on 96 cylinders made of multiple batches of concrete with varying amounts of basalt fibre additives of the two mentioned types, along with control batches containing no fibres. Furthermore, flexural tests on 24 prisms were carries out to measure the modulus of rupture, in addition to 30 prisms for average residual strength test. Results of the research indicated that use of basalt fibres has insignificant effects on compressive strength of plain concrete, where the increase in strength did not exceed about 5%. On the other hand, results suggest that the use of basalt fibres may increase the compressive strength of concrete containing fly as up top 40%. The rupture strength was increased also by 8% to 28% depending on mix and fibre types and contents. Finally, there was no clear correlation between the average residual strength and ratios of basalt fibres mixed with the different concrete batches.

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...

Effects of chemical treatments on hemp fibre structure

Energy Technology Data Exchange (ETDEWEB)

Kabir, M.M., E-mail: kabirm@usq.edu.au [Centre of Excellence in Engineered Fibre Composite (CEEFC), Faculty of Engineering and Surveying, University of Southern Queensland, Toowoomba, Queensland 4350 (Australia); Wang, H. [Centre of Excellence in Engineered Fibre Composite (CEEFC), Faculty of Engineering and Surveying, University of Southern Queensland, Toowoomba, Queensland 4350 (Australia); Lau, K.T. [Centre of Excellence in Engineered Fibre Composite (CEEFC), Faculty of Engineering and Surveying, University of Southern Queensland, Toowoomba, Queensland 4350 (Australia); Department of Mechanical Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong Special Administrative Region (Hong Kong); Cardona, F. [Centre of Excellence in Engineered Fibre Composite (CEEFC), Faculty of Engineering and Surveying, University of Southern Queensland, Toowoomba, Queensland 4350 (Australia)

2013-07-01

In this study, hemp fibres were treated with alkali, acetyl and silane chemicals. Fibre constituents such as cellulose, hemicellulose and lignin constituents were separated from treated fibres. The chemical and thermal influences of these constituents on the treated fibres were examined by using scanning electron microscope (SEM), fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). Experimental results revealed that, hemicellulose was degraded faster than that of cellulose and lignin. Cellulose exhibited better thermal stability and lignin was degraded in a wide range of temperatures. The hydrophilic nature of the fibres was predominantly caused by the presence of hemicellulose and then lignin constituents. Hemicellulose and lignin were mostly removed by the alkalisation with higher concentrations of NaOH, followed by acetylation. Silane treatment could not remove the hemicellulose and lignin, rather this treatment facilitated coupling with the fibre constituents.

Effects of chemical treatments on hemp fibre structure

International Nuclear Information System (INIS)

Kabir, M.M.; Wang, H.; Lau, K.T.; Cardona, F.

2013-01-01

In this study, hemp fibres were treated with alkali, acetyl and silane chemicals. Fibre constituents such as cellulose, hemicellulose and lignin constituents were separated from treated fibres. The chemical and thermal influences of these constituents on the treated fibres were examined by using scanning electron microscope (SEM), fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). Experimental results revealed that, hemicellulose was degraded faster than that of cellulose and lignin. Cellulose exhibited better thermal stability and lignin was degraded in a wide range of temperatures. The hydrophilic nature of the fibres was predominantly caused by the presence of hemicellulose and then lignin constituents. Hemicellulose and lignin were mostly removed by the alkalisation with higher concentrations of NaOH, followed by acetylation. Silane treatment could not remove the hemicellulose and lignin, rather this treatment facilitated coupling with the fibre constituents.

Factors That Improve the Impact Responses of Ukam Plant Fibre ...

African Journals Online (AJOL)

Natural fibres around us have mechanical properties capable of making them compete effectively with synthetic fibres in the development of fibre reinforced composites. Synthetic fibres (such as glass fibres) and resins (such as polyester resin) have long been used in the development of structural components for car bodies, ...

Fibre optics compatibility with radiative environment inside PWR containment

International Nuclear Information System (INIS)

Breuze, G.; Jucker, P.; Serre, J.

1993-01-01

Fibre optic links operating with multiplexed sensors data are potentially attractive for nuclear power plant applications. It hence became essential to test for radiation vulnerability not only transmission support -fibres- but also fibre-end electro-optical components which could be exposed to hostile environment, perhaps in worse conditions than fibres. Present paper gives results of multimode silica-based fibre behaviour during long-term steady-state low dose-rate gamma ray exposure - one year under 0.1 to 0.2 Gy/h. Studies concerned radiation-induced loss (ΔL) measurement of eight different commercially available fibres and bit error-rate (BER) recording of four 1 100 m length data links operating with a 100 m part exposed to gamma-rays. Main result is the good behaviour of pure silica-core fibres, especially a step-index polymer-clad fibre transmitting 850 nm light but also a graded-index fluorine-clad fibre for 1 300 nm window. Mean ΔL values are respectively 3 dB/km and 4.5 dB/km at the exposure end. Complementary result is no influence of gamma-ray exposure upon data link initial 10 -9 BER. (authors). 9 figs., 7 tabs., 26 refs

Genetic analysis of fibre quality traits in upland cotton

International Nuclear Information System (INIS)

Khan, I.A.; Shakeel, A.; Azhar, F.M.

2001-01-01

Five-parent diallel cross data were analysed following Hayman-Jinks genetic model in order to study pattern of inheritance of staple length, fibre strength, fibre fineness and fibre uniformity of upland cotton. The regression analysis of the F/sub 1/ data revealed that the simple additive dominance model was adequate for genetic analysis. Graphic analysis showed the presence of over-dominance type of gene action in the inheritance e of all the traits. The comparison of array means indicated that varieties Co-2-1 and B-682 had good general combining ability for staple length and fibre strength respectively, whilst CIM-443 showed better general combining ability for fibre fineness and fibre uniformity than the other varieties. The cross combination of Co-2-1 and CIM-443 with B-682 expressed best specific combining ability for staple length and fibre uniformity respectively. Similarly variety B-682 nickel well with DPL 7740-424 for the fibre strength, and coker-307 with CO-2-1 for fibre fineness. The type of gene action controlling inheritance of these characters, and better performance of some of the hybrids suggest that improvement may be possible by developing on appropriate breeding programme. (author)

Design of dual-mode optical fibres for the FTTH applications

Science.gov (United States)

Chen, Ming-Yang; Li, Yu-Rong; Zhang, Yin; Zhu, Yuan-Feng; Zhang, Yong-Kang; Zhou, Jun

2011-01-01

We present in this article a proposal and design for dual-mode optical fibres for fibre-to-the-home applications. High-order modes in the fibre can be effectively suppressed by the connection of the fibre with standard single-mode optical fibres at the two ends of the fibre. The alignment tolerance at the splicing process is presented. In particular, a low bending loss operation with low splice loss is demonstrated using the proposed technique.

Design of dual-mode optical fibres for the FTTH applications

International Nuclear Information System (INIS)

Chen, Ming-Yang; Li, Yu-Rong; Zhang, Yin; Zhu, Yuan-Feng; Zhang, Yong-Kang; Zhou, Jun

2011-01-01

We present in this article a proposal and design for dual-mode optical fibres for fibre-to-the-home applications. High-order modes in the fibre can be effectively suppressed by the connection of the fibre with standard single-mode optical fibres at the two ends of the fibre. The alignment tolerance at the splicing process is presented. In particular, a low bending loss operation with low splice loss is demonstrated using the proposed technique

Optical fibres in the radiation environment of CERN

Science.gov (United States)

Guillermain, E.

2017-11-01

CERN, the European Organization for Nuclear Research (in Geneva, Switzerland), is home to a complex scientific instrument: the 27-kilometre Large Hadron Collider (LHC) collides beams of high-energy particles at close to the speed of light. Optical fibres are widely used at CERN, both in surface areas (e.g. for inter-building IT networks) and in the accelerator complex underground (e.g. for cryogenics, vacuum, safety systems). Optical fibres in the accelerator are exposed to mixed radiation fields (mainly composed of protons, pions, neutrons and other hadrons, gamma rays and electrons), with dose rates depending on the particular installation zone, and with radiation levels often significantly higher than those encountered in space. In the LHC and its injector chain radiation levels range from relatively low annual doses of a few Gy up to hundreds of kGy. Optical fibres suffer from Radiation Induced Attenuation (RIA, expressed in dB per unit length) that affect light transmission and which depends on the irradiation conditions (e.g. dose rate, total dose, temperature). In the CERN accelerator complex, the failure of an optical link can affect the proper functionality of control or monitoring systems and induce the interruption of the accelerator operation. The qualification of optical fibres for installation in critical radiation areas is therefore crucial. Thus, all optical fibre types installed in radiation areas at CERN are subject to laboratory irradiation tests, in order to evaluate their RIA at different total dose and dose rates. This allows the selection of the appropriate optical fibre type (conventional or radiation resistant) compliant with the requirements of each installation. Irradiation tests are performed in collaboration with Fraunhofer INT (irradiation facilities and expert team in Euskirchen, Germany). Conventional off-the-shelf optical fibres can be installed for optical links exposed to low radiation levels (i.e. annual dose typically below few

Life cycle strain monitoring in glass fibre reinforced polymer laminates using embedded fibre Bragg grating sensors from manufacturing to failure

DEFF Research Database (Denmark)

Nielsen, Michael Wenani; Schmidt, Jacob Wittrup; Høgh, Jacob Herold

2013-01-01

A holistic approach to strain monitoring in fibre-reinforced polymer composites is presented using embedded fibre Bragg grating sensors. Internal strains are monitored in unidirectional E-glass/epoxy laminate beams during vacuum infusion, curing, post-curing and subsequent loading in flexure until...... of the different cure temperatures and tool/part interfaces used. Substantial internal process-induced strains develop in the transverse fibre direction, which should be taken into consideration when designing fibre-reinforced polymer laminates. Flexure tests indicate no significant difference in the mechanical...

Removal of hexavalent Cr by coconut coir and derived chars--the effect of surface functionality.

Science.gov (United States)

Shen, Ying-Shuian; Wang, Shan-Li; Tzou, Yu-Min; Yan, Ya-Yi; Kuan, Wen-Hui

2012-01-01

The Cr(VI) removal by coconut coir (CC) and chars obtained at various pyrolysis temperatures were evaluated. Increasing the pyrolysis temperature resulted in an increased surface area of the chars, while the corresponding content of oxygen-containing functional groups of the chars decreased. The Cr(VI) removal by CC and CC-derived chars was primarily attributed to the reduction of Cr(VI) to Cr(III) by the materials and the extent and rate of the Cr(VI) reduction were determined by the oxygen-containing functional groups in the materials. The contribution of pure Cr(VI) adsorption to the overall Cr(VI) removal became relatively significant for the chars obtained at higher temperatures. Accordingly, to develop a cost-effective method for removing Cr(VI) from water, the original CC is more advantageous than the carbonaceous counterparts because no pyrolysis is required for the application and CC has a higher content of functional groups for reducing Cr(VI) to less toxic Cr(III). Copyright © 2011 Elsevier Ltd. All rights reserved.

Soybean Protein Fibres Part 2: Soybean Fibres Properties and Application Areas

Directory of Open Access Journals (Sweden)

Fatma Filiz Yıldırım

2015-01-01

Full Text Available Soybean protein fibres (SPF, which is a protein based botanic fibre, has various beneficialproperties such as softness, brightness, smoothness, drape, UV and bacterial resistance. These fibers areused in production of various yarn blends, woven, knit and nonwoven fabrics to manufature apperal andhome textiles such as t-shirts, bedding, sweater and baby dress due to these superior properties. This review,about SPF, is divided into two sections. In the first part; structure and production stages of SPF and itsenviromental effects had been described. In the second part of this review, properties and application areasof SPF have been described.

Cool application for Optical Fibres

CERN Multimedia

2001-01-01

In a new first for CERN, optical fibres have been put on test to measure very low temperatures. If these tests prove successful, this new technology could lead to important cost-saving changes in the way the temperatures of superconducting magnets are measured. There was excitement in the air last March when the team led by Walter Scandale and Luc Thévenaz tested very low temperature measurement using optical fibres. This spring in CERN's Cryogenics lab an idea was put to the test as a new kind of low-temperature thermometry using optical fibres was tested down to 2 Kelvin (around 300 degrees below room temperature), and the first results are looking good. Optical fibres are well known for their ability to carry large amounts of data around the world, but it is less well known that they can be used for measuring temperatures. The intuition that they might be able to measure very low temperatures - such as those of the LHC magnets - came to the attention of CERN's Walter Scandale at the Optical Fi...

Zeonex Microstructured Polymer Optical Fibre Bragg Grating Sensor

DEFF Research Database (Denmark)

Woyessa, Getinet; Fasano, Andrea; Markos, Christos

2016-01-01

We fabricated an endlessly single mode and humidity insensitive Zeonex microstructured polymer optical fibre (mPOF) for fibre Bragg grating (FBG) temperature and strain sensors. We inscribed and characterise FBGs in Zeonex mPOF for the first time.......We fabricated an endlessly single mode and humidity insensitive Zeonex microstructured polymer optical fibre (mPOF) for fibre Bragg grating (FBG) temperature and strain sensors. We inscribed and characterise FBGs in Zeonex mPOF for the first time....

FTIR characterization ans chemo-mechanical distinction of reted kenaf fibres

Directory of Open Access Journals (Sweden)

Emannuel Omenna

2017-12-01

Full Text Available Inadequate information on the binding characteristics of kenaf biomass at the molecular level has adversely affected the modifications of its cellulose-hemicellulose-lignin structure. This study was undertaken to assess the characteristic features and chemo-mechanical properties of kenaf fibres retted under three different media namely: tank, stream and ribbon. Fourier transform infra-red (FTIR spectra analysis as well as the ASTM standard for tensile tests were applied. The results showed that the broad bands occurred at the range of 3312- 3420 cm−1 for all the retted fibres were due to the presence of hydroxyl (–OH group while the peaks were obtained at 1635.76, 1635.34, and 1730.69 cm−1 for stream, tank and ribbon retted fibres respectively. However, tank retted fibres had the most broad band intensity at 3419.78cm-1 while ribbon fibres had the highest absorption peak of 1730.69cm-1 corresponding to C=O stretching of the acetyl group in hemi-cellulose. Stream retted Kenaf fibres had the highest tensile strength followed by the tank retted fibres while ribbon fibres had the least. Furthermore, there was no significant difference between stream and tank retted Kenaf fibres in terms of tensile modulus and this was significantly higher than that of ribbon fibre. The α-cellulose content of stream retted fibres was slightly higher than that of ribbon fibres while tank retted fibres had the least. From the results, tank retted Kenaf fibre was ranked as ‘the best fibre’ with the most intensive broad bands and least in lignin and hemi-cellulose content which were regarded as the impurities, gummy and waxy materials, responsible for an easy deformation of the fibre cellular networks.

Panel Board From Coconut Fibre And Pet Bottle

Directory of Open Access Journals (Sweden)

Ngadiman Norhayati

2018-01-01

Full Text Available The rate of global deforestation and its impact on the environment has led particle board manufacture to search for alternative feedstock, especially in countries where wood is less available compared to other cellulosic natural product. Based on the properties of coconut fibre and PET bottle, these two materials can be recycle as raw material for manufacture of panel board. As for this study, the coconut fibre were used as the filler and PET bottle as outer lining of the panel board. Two types of coconut fibre were used which are grinding and un-grinding coconut fibre. At first, the coconut fibre are undergoes softening, grinding, drying and sieving process, while PET bottle was cleaning, shredding, sieving before compacted using hydraulic hot press machine. There are four types of testing that been carried out which are swelling, water absorption, Modulus of Elasticity (MOE and Modulus of Rupture (MOR. The result show the conventional board has the highest value for MOE test, so it’s indicate that the conventional board is less strength from the coconut fibre board. As for water absorption test, the average water absorption of coconut fibre based panel board is less than conventional board. Overall, the coconut fibre board is better than conventional panel board because coconut fibre board are less swelling, has low water absorption, high modulus of rupture and low modulus of elasticity. Based on the finding, this coconut fibre panel board has potential as a stronger and long-lasting panel board than the conventional board in the market. Other than that, the panel also have their own aesthetic value since the recycled plastic bottle used as outer lining is colourful and giving aesthetic value.

Superoleophillic electrospun polystrene/exofoliated graphite fibre for selective removal of crude oil from water

Science.gov (United States)

Alayande, S. Oluwagbemiga; Dare, Enock O.; Olorundare, F. O. Grace; Nkosi, D.; Msagati, Titus A. M.; Mamba, B. B.

2016-04-01

During oil spills, the aquatic environment is greatly endangered because oil floats on water making the penetration of sunlight difficult therefore primary productivity is compromised, birds and aquatic organisms are totally eliminated within a short period. It is therefore essential to remove the oil from the water bodies after the spillage. This work reports on the fabrication of oil loving electrospun polystyrene-exofoliated graphite fibre with hydrophobic and oleophillic surface properties. The fibre was applied for the selective adsorption of crude oil from simulated crude oil spillage on water. The maximum oil adsorption capacity of the EPS/EG was 1.15 kg/g in 20 min while the lowest oil adsorption capacity was 0.81 kg/g in 10 min. Cheap oil adsorbent was developed with superoleophillic and superhydrophobic properties.

Design of DFB fibre lasers

DEFF Research Database (Denmark)

Lauridsen, Vibeke Claudia; Povlsen, Jørn Hedegaard; Varming, Poul

1998-01-01

A numerical model for erbium distributed feedback (DFB) fibre lasers is presented. The model is used to optimise the location of a discrete phase-shift to obtain maximum output power. For DFB fibre lasers of up to 10cm in length it is shown that the influence of Kerr nonlinearity with respect to ...... to output power is negligible....

Application of Raman spectroscopy to forensic fibre cases.

Science.gov (United States)

Lepot, L; De Wael, K; Gason, F; Gilbert, B

2008-09-01

Five forensic fibre cases in which Raman spectroscopy proved to be a good complementary method for microspectrophotometry (MSP) are described. Absorption spectra in the visible range are indeed sometimes characteristic ofa certain dye but this one can be subsequently identified unambiguously by Raman spectroscopy using a spectral library. In other cases the comparison of Raman spectra of reference fibres and suspect fibres led to an improvement of the discrimination power. The Raman measurements have been performed directly on mounted fibres and the spectra showed only little interference from the mounting resin and glass. Raman spectroscopy is therefore a powerful method that can be applied in routine fibre analysis following optical microscopy and MSP measurements.

Meal replacements and fibre supplement as a strategy for weight loss. Proprietary PGX® meal replacement and PGX® fibre supplement in addition to a calorie-restricted diet to achieve weight loss in a clinical setting.

Science.gov (United States)

Reichert, Ronald G; Reimer, Raylene A; Kacinik, Veronica; Pal, Sebely; Gahler, Roland J; Wood, Simon

2013-01-01

Meal replacements and viscous soluble fibre represent safe and sustainable aids for weight loss. Our purpose was to determine if PGX® meal replacements and PGX(®) fibre complex in combination with a calorie-restricted diet would aid in weight loss in a clinical setting. Fifty-two overweight and obese participants (49 women, 3 men; average age 47.1 years) with a mean body mass index (BMI) of 33.8 ± 6.4 kg/m(2) consumed 57 g of proprietary PGX® meal replacement product at breakfast and another 57 g at lunch for 12 weeks. In addition to the meal replacements, they were also asked to consume 5 g/day of PGX® fibre in the form of granules, powder or capsules together with 250 mlwater. A registered dietician recommended low-fat, low-glycaemic-index foods for snacks and the dinner menus such that each volunteer was consuming a total of 1200 kcal/day. All participants (n = 52) lost a significant amount of weight from baseline (-4.69 ± 3.73 kg), which was further reflected in the reductions in their waist (-7.11 ± 6.35 cm) and hip circumference (-5.59 ± 3.58 cm) over the 12-week study (p meal replacements and PGX(®) fibre along with a controlled dietary caloric intake is of benefit for short-term weight loss.

In vitro fracture resistance of molar teeth restored with a short fibre-reinforced composite material.

Science.gov (United States)

Fráter, Márk; Forster, András; Keresztúri, Márk; Braunitzer, Gábor; Nagy, Katalin

2014-09-01

The purpose of this in vitro study was to evaluate the efficiency of a short fibre-reinforced composite (SFRC) material compared to conventional composites when restoring class II. MOD cavities in molar teeth with different layering techniques. One hundred and thirty mandibular third molars were divided into 5 groups (n=26). Except for the control group (intact teeth), in all other groups MOD cavities were prepared. The cavities were restored by either conventional composite with horizontal and oblique layering or by SFRC with horizontal and oblique layering. The specimens were submitted to static fracture toughness test. Fracture thresholds and fracture patterns were evaluated. In general, no statistically significant difference was found in fracture toughness between the study groups, except for horizontally layered conventional composite restorations, which turned out to be significantly weaker than controls. However, SFRC yielded noticeably higher fracture thresholds and only obliquely applied SFRC restorations exhibited favourable fracture patterns above chance level. The application of SFRC did not lead to a statistically significant improvement of the fracture toughness of molar teeth with MOD cavities. Still, SFRC applied in oblique increments measurably reduces the chance of unrestorable fractures of molar teeth with class II MOD cavities. The restoration of severely weakened molar teeth with the use of SFRC combined with composite might have advantages over conventional composites alone. It was observed from the statistical data, that the application of SFRC with an oblique layering technique yielded not significantly but better fracture thresholds and more favourable fracture patterns than any other studied material/technique combination. Thus further investigations need to be carried out, to investigate the possible positive mechanical effects of SFRC. The application of the horizontal layering technique with conventional composite materials is inferior

Engineering Performance of High Strength Concrete Containing Steel Fibre Reinforcement

Directory of Open Access Journals (Sweden)

Md Azree Othuman Mydin

2013-09-01

Full Text Available The development and utilization of the high strength concrete in the construction industry have been increasing rapidly. Fiber reinforced concrete is introduced to overcome the weakness of the conventional concrete because concrete normally can crack under a low tensile force and it is known to be brittle. Steel fibre is proved to be the popular and best combination in the high strength concrete to result the best in the mechanical and durability properties of high strength concrete with consideration of curing time, steel fibre geometry, concrete grade and else more. The incorporation of steel fibre in the mortar mixture is known as steel fibre reinforced concrete have the potential to produce improvement in the workability, strength, ductility and the deformation of high strength concrete. Besides that, steel fibre also increases the tensile strength of concrete and improves the mechanical properties of the steel fibre reinforced concrete. The range for any high strength concrete is between 60MPa-100MPa. Steel fibre reinforced concrete which contains straight fibres has poorer physical properties than that containing hooked end stainless steel fibre due to the length and the hooked steel fibre provide a better effective aspects ratio. Normally, steel fibre tensile strength is in the range of 1100MPa-1700MPa. Addition of less steel fibre volumes in the range of 0.5% to 1.0% can produce better increase in the flexural fatigue strength. The strength can be increased with addition of steel fibre up to certain percentage. This paper will review and present some basic properties of steel fibre reinforced concrete such as mechanical, workability and durability properties.

EXPERIMENTAL STUDY ON LIGHT TRANSMITTING CONCRETE BY USING OPTICAL FIBRE

OpenAIRE

S. Suganya; S. Minu Gopika

2017-01-01

Light transmitting concrete is one of the fibre reinforced concrete which is mainly used for aesthetic application by incorporating the optical fibres in concrete. Optical fibres help to transmit the light through the fibres and the end-light type of fibre is used to increase the aesthetic appearance of the concrete which is like a transparent concrete. Fibres are arranged in different layers, to increase the load carrying capacity and also the pattern can be created to make the concrete deco...

Natural Pineapple Leaf Fibre Extraction On Josapine And Morris

OpenAIRE

Mazalan Muhammad Firdaus; Yusof Yusri

2017-01-01

The pineapple’s leaf plant contains approximately 2.5% to 3.5% of strong white silky fibres. These fibres are useful and can be extracted from the leaves. There are a few ways to extract the fibre such as hand scrapping and by extraction machine. The objective of this research is to study the quality of fibre extraction by using different age of pineapple leaf. Next, the study aims to compare the quality of Josapine and Morris pineapple leaf with tensile test. Fibre yield percentage are calcu...

Mechanical and thermal properties of short-coirfiber-reinforced natural rubber/polyethylene composites

Science.gov (United States)

Xu, Zh. H.; Kong, Zh. N.

2014-07-01

Natural rubber (NR) and polyethylene (PE) composites were compounded with chemically treated coir fibers by using a heated two-roll mill. Two chemical treatments of the fibers — by silane and sodium hydroxide — were carried out to improve the interfacial adhesion between them and the polyethylene matrix. The mechanical properties of the composites obtained were evaluated and compared with those made from a neat polymer and untreated fibers. The mechanical properties of the composites, such as the tensile strength, Young's modulus, and the elongation at break, were examined, and their shrinkage and flame retardant characteristics were measured. From these experiments, the effect of plasma treatment on the mechanical-physical behavior of coconut-fiberreinforced NR/PE composites was identified. In addition, their thermal characteristics were evaluated, and the results showed a slight decrease in them with increasing content of coir fibers.

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)

Cellulose fibres, nanofibrils and microfibrils: The morphological sequence of MFC components from a plant physiology and fibre technology point of view

Directory of Open Access Journals (Sweden)

Chinga-Carrasco Gary

2011-01-01

Full Text Available Abstract During the last decade, major efforts have been made to develop adequate and commercially viable processes for disintegrating cellulose fibres into their structural components. Homogenisation of cellulose fibres has been one of the principal applied procedures. Homogenisation has produced materials which may be inhomogeneous, containing fibres, fibres fragments, fibrillar fines and nanofibrils. The material has been denominated microfibrillated cellulose (MFC. In addition, terms relating to the nano-scale have been given to the MFC material. Several modern and high-tech nano-applications have been envisaged for MFC. However, is MFC a nano-structure? It is concluded that MFC materials may be composed of (1 nanofibrils, (2 fibrillar fines, (3 fibre fragments and (4 fibres. This implies that MFC is not necessarily synonymous with nanofibrils, microfibrils or any other cellulose nano-structure. However, properly produced MFC materials contain nano-structures as a main component, i.e. nanofibrils.

Cellulose fibres, nanofibrils and microfibrils: The morphological sequence of MFC components from a plant physiology and fibre technology point of view.

Science.gov (United States)

Chinga-Carrasco, Gary

2011-06-13

During the last decade, major efforts have been made to develop adequate and commercially viable processes for disintegrating cellulose fibres into their structural components. Homogenisation of cellulose fibres has been one of the principal applied procedures. Homogenisation has produced materials which may be inhomogeneous, containing fibres, fibres fragments, fibrillar fines and nanofibrils. The material has been denominated microfibrillated cellulose (MFC). In addition, terms relating to the nano-scale have been given to the MFC material. Several modern and high-tech nano-applications have been envisaged for MFC. However, is MFC a nano-structure? It is concluded that MFC materials may be composed of (1) nanofibrils, (2) fibrillar fines, (3) fibre fragments and (4) fibres. This implies that MFC is not necessarily synonymous with nanofibrils, microfibrils or any other cellulose nano-structure. However, properly produced MFC materials contain nano-structures as a main component, i.e. nanofibrils.

Mechanical properties of thermoplastic composites reinforced with Entada Mannii fibre

Directory of Open Access Journals (Sweden)

Oluwayomi BALOGUN

2017-06-01

Full Text Available The mechanical properties and fracture mechanisms of thermoplastic composites reinforced with Entada mannii fibres was investigated. Polypropylene reinforced with 1, 3, 5, and 7 wt% KOH treated and untreated Entada mannii fibres were processed using a compression moulding machine. The tensile properties, impact strength, and flexural properties of the composites were evaluated while the tensile fracture surface morphology was examined using scanning electron microscopy. The results show that reinforcing polypropylene with Entada mannii fibres resulted in improvement of the tensile strength and elastic modulus. This improvement is remarkable for 5 wt% KOH treated Entada mannii fibre reinforced composites by 28 % increase as compared with the unreinforced polypropylene. The composites reinforced with Entada mannii fibres also had impact strength values of 70 % higher than the unreinforced polypropylene. However, the polypropylene reinforced with 5 and 7wt% KOH treated fibres exhibited significantly higher flexural strength and Young’s modulus by 53% and 52% increase as compared with the unreinforced polypropylene. The fracture surface of the polypropylene composites reinforced with untreated Entada mannii fibres were characterized by fibre debonding, fibre pull-out and matrix yielding while less voids and fibre pull-outs are observed in the composites reinforced with KOH treated Entada mannii fibres. v

Optimisation of mechanical properties of bamboo fibre reinforced-PLA biocomposites

Science.gov (United States)

Nurnadia M., J.; Fazita, M. R. Nurul; Abdul Khalil H. P., S.; Mohamad Haafiz M., K.

2017-12-01

The majority of the raw materials that have been widely used in industries are petroleum-based. Growing environmental awareness, the depletion of fossil fuels, and climate change are the key drivers to seek more ecologically friendly materials, such as natural fibres to replace synthetic fibres in polymeric composite. Among the natural fibres available, bamboo fibre has relatively high strength. Poly (lactic) acid (PLA), one of the well-known biopolymers, has been used as a matrix in order to produce totally biodegradable biocomposites. In this study, bamboo fibres were compounded with PLA by a twin screw extruder. The bamboo fibre reinforced PLA composites were then manufactured via the compression moulding method. The influences of screw speed and die temperature during extrusion on the mechanical properties, the tensile and flexural of the biocomposites, were studied. The effects of fibre content and fibre length were also investigated. Taguchi experimental design approach was adopted to determine the optimum set of conditions to achieve the "best" mechanical properties of the composites. Tensile and flexural properties were characterised based on the D638-10 and D790-10 standards, respectively. It was observed that the fibre aspect ratio and fibre content significantly affected the mechanical performance of bamboo fibres reinforced PLA composites.

Simplifying the design of microstructured optical fibre pressure sensors.

Science.gov (United States)

Osório, Jonas H; Chesini, Giancarlo; Serrão, Valdir A; Franco, Marcos A R; Cordeiro, Cristiano M B

2017-06-07

In this paper, we propose a way to simplify the design of microstructured optical fibres with high sensitivity to applied pressure. The use of a capillary fibre with an embedded core allows the exploration of the pressure-induced material birefringence due to the capillary wall displacements and the photoelastic effect. An analytical description of pressure-induced material birefringence is provided, and fibre modal characteristics are explored through numerical simulations. Moreover, a capillary fibre with an embedded core is fabricated and used to probe pressure variations. Even though the embedded-core fibre has a non-optimized structure, measurements showed a pressure sensitivity of (1.04 ± 0.01) nm/bar, which compares well with more complex, specially designed fibre geometries reported in the literature. These results demonstrate that this geometry enables a novel route towards the simplification of microstructured fibre-based pressure sensors.

Self-centring technique for fibre optic microlens mounting using a concave cone-etched fibre

International Nuclear Information System (INIS)

Demagh, Nacer-Eddine; Guessoum, Assia; Zegari, Rabah; Gharbi, Tijani

2011-01-01

Several techniques of centring a microlens onto the fibre optic end face are studied. In most of them, microsphere lenses are centred with the aid of high-accuracy micro-positioners. This process is complicated with regard to the difficulty in manipulating microsphere lenses. In this paper, a simple and accurate self-centring method for mounting microsphere lenses using a concave cone etched fibre (Demagh et al 2006 Meas. Sci. Technol. 17 119–22) is described. This technique allows the centring of a wide variety of microlens radii, typically 7 µm to over 24 µm. The proposed process, however, is not affected by any spatial positioning control of microspheres. In over 85% of the attempts, the microsphere lenses were centred on the fibre axis to within 0.12 µm

ETUDE DE L' ARRACHEMENT DES FIBRES METALLIQUES ET CARACTERISATION DE LA LIAISON FIBRE MATRICE

Directory of Open Access Journals (Sweden)

F Z MIMOUNE

2002-12-01

Full Text Available Cette étude compare trois modes de caractérisation mécanique des propriétés de la liaison fibre matrice dans un composite d’argile ciment fibre d’acier. Des essais ont été effectués avec différents diamètres de fibres afin de mesurer une contrainte d’adhérence. Les différents résultats montrent la nature complexe de la liaison avec chacune des trois méthodes. Une explication du mécanisme et de la divergence des résultats est proposée, qui conduit à préférer l’un des trois tests vis-à-vis de son utilisation pour prévoir les qualités du composite.

Natural Composites: Cellulose Fibres and the related Performance of Composites

DEFF Research Database (Denmark)

Lilholt, Hans; Madsen, Bo

2014-01-01

Biobased materials are becoming of increasing interest as potential structural materials for the future. A useful concept in this context is the fibre reinforcement of materials by stiff and strong fibres. The biobased resources can contribute with cellulose fibres and biopolymers. This offers th...... in stiffness, on the packing ability of cellulose fibres and the related maximum fibre volume fraction in composites, on the moisture sorption of cellulose fibres and the related mass increase and (large) hygral strains induced, and on the mechanical performance of composites....

Tensile properties of compressed moulded Napier/glass fibre reinforced epoxy composites

Science.gov (United States)

Fatinah, T. S.; Majid, M. S. Abdul; Ridzuan, M. J. M.; Hong, T. W.; Amin, N. A. M.; Afendi, M.

2017-10-01

This paper describes the experimental investigation of the tensile properties of compressed moulded Napier grass fibres reinforced epoxy composites. The effect of treatment 5% sodium hydroxide (NaOH) concentrated solution and hybridization of Napier with CSM E-glass fibres on tensile properties was also studied. The untreated and treated Napier fibres with 25% fibre loading were fabricated with epoxy resin by a cold press process. 7% fibre loading of CSM glass fibre was hybrid as the skin layer for 18% fibre loading of untreated Napier grass fibre. The tensile tests were conducted using Universal Testing Machine in accordance with ASTM D638. The tensile properties of the untreated Napier/epoxy composites were compared with treated Napier/epoxy and untreated Napier/CSM/epoxy composites. The results demonstrated that the tensile performance of untreated Napier fibre composites was significantly improved by both of the modification; alkali treatment and glass fibre hybridization. Napier grass fibres showed promising potentials to be used as reinforcement in the polymer based composites.

The magnetic properties of aligned M hexa-ferrite fibres

International Nuclear Information System (INIS)

Pullar, R.C.; Bhattacharya, A.K.

2006-01-01

Aligned and random fibres of strontium hexa ferrite (SrM, SrFe 12 O 19 ) and barium hexaferrite (BaM, BaFe 12 O 19 ) were manufactured by blow spinning from an aqueous inorganic sol-gel precursor, which was then fired to give the hexagonal ferrite fibre. Their magnetic properties were studied by VSM, investigating the evolution of these properties with firing and measurement temperature, and in particular the effects of fibre alignment. It has been predicted that aligned ferrite fibres will demonstrate an enhanced magnetisation along the axis of alignment with respect to perpendicular to the axis, and this has been demonstrated here for the first time. The optimum firing temperature was 1000 deg. C, at which point they still had submicron grains. In BaM random fibres M s =63.8 emu g -1 and H c =428.1 kA m -1 , and in SrM random fibres M s =63.3 emu g -1 and H c =452.8 kA m -1 , high values for polycrystalline materials. Fibres aligned parallel to the applied field had saturation magnetisation (M s ) values equal to those of the random fibres, whilst fibres aligned perpendicular to the field had M s values 62% and 75% lower, for BaM and SrM, respectively. There was no change in coercivity (H c ) between random or aligned fibres of any orientation, and fibres aligned 45 deg. and parallel to H appeared identical. Therefore, properties along the axis of alignment were superior when compared to measurements perpendicular to the axis of alignment, giving a directionality to the magnetisation in an otherwise randomly oriented ferrite material

A statistical analysis of fibre size and shape distribution after compounding in composites reinforced by natural fibres

NARCIS (Netherlands)

Moigne, Le N.; Oever, van den M.J.A.; Budtova, T.

2011-01-01

Using high resolution optical microscopy coupled with image analysis software and statistical methods, fibre length and aspect ratio distributions in polypropylene composites were characterized. Three types of fibres, flax, sisal and wheat straw, were studied. Number and surface weighted

Crack Growth Monitoring by Embedded Optical Fibre Bragg Grating Sensors: Fibre Reinforced Plastic Crack Growing Detection

DEFF Research Database (Denmark)

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

2015-01-01

This article presents a novel method to asses a crack growing/damage event in fibre reinforced plastic, or adhesive using Fibre Bragg Grating (FBG) sensors embedded in a host material. Different features of the crack mechanism that induce a change in the FBG response were identified. Double Canti...

Recent advances in poled optical fibres

DEFF Research Database (Denmark)

Pruneri, V.; Margulis, W.; Myrén, N.

2005-01-01

A second-order nonlinearity can be induced in optical fibres through poling. We describe accomplishments of the EU project GLAMOROUS in making low-cost high performance electrooptic and nonlinear optical fibre- and waveguide-based components. In particular a comparison with more traditional...

Optical Fibre Pressure Sensors in Medical Applications

Directory of Open Access Journals (Sweden)

Sven Poeggel

2015-07-01

Full Text Available This article is focused on reviewing the current state-of-the-art of optical fibre pressure sensors for medical applications. Optical fibres have inherent advantages due to their small size, immunity to electromagnetic interferences and their suitability for remote monitoring and multiplexing. The small dimensions of optical fibre-based pressure sensors, together with being lightweight and flexible, mean that they are minimally invasive for many medical applications and, thus, particularly suited to in vivo measurement. This means that the sensor can be placed directly inside a patient, e.g., for urodynamic and cardiovascular assessment. This paper presents an overview of the recent developments in optical fibre-based pressure measurements with particular reference to these application areas.

Optical Fibre Pressure Sensors in Medical Applications.

Science.gov (United States)

Poeggel, Sven; Tosi, Daniele; Duraibabu, DineshBabu; Leen, Gabriel; McGrath, Deirdre; Lewis, Elfed

2015-07-15

This article is focused on reviewing the current state-of-the-art of optical fibre pressure sensors for medical applications. Optical fibres have inherent advantages due to their small size, immunity to electromagnetic interferences and their suitability for remote monitoring and multiplexing. The small dimensions of optical fibre-based pressure sensors, together with being lightweight and flexible, mean that they are minimally invasive for many medical applications and, thus, particularly suited to in vivo measurement. This means that the sensor can be placed directly inside a patient, e.g., for urodynamic and cardiovascular assessment. This paper presents an overview of the recent developments in optical fibre-based pressure measurements with particular reference to these application areas.

Optical Fibre Pressure Sensors in Medical Applications

Science.gov (United States)

Poeggel, Sven; Tosi, Daniele; Duraibabu, DineshBabu; Leen, Gabriel; McGrath, Deirdre; Lewis, Elfed

2015-01-01

This article is focused on reviewing the current state-of-the-art of optical fibre pressure sensors for medical applications. Optical fibres have inherent advantages due to their small size, immunity to electromagnetic interferences and their suitability for remote monitoring and multiplexing. The small dimensions of optical fibre-based pressure sensors, together with being lightweight and flexible, mean that they are minimally invasive for many medical applications and, thus, particularly suited to in vivo measurement. This means that the sensor can be placed directly inside a patient, e.g., for urodynamic and cardiovascular assessment. This paper presents an overview of the recent developments in optical fibre-based pressure measurements with particular reference to these application areas. PMID:26184228

A Grey Fuzzy Logic Approach for Cotton Fibre Selection

Science.gov (United States)

Chakraborty, Shankar; Das, Partha Protim; Kumar, Vidyapati

2017-06-01

It is a well known fact that the quality of ring spun yarn predominantly depends on various physical properties of cotton fibre. Any variation in these fibre properties may affect the strength and unevenness of the final yarn. Thus, so as to achieve the desired yarn quality and characteristics, it becomes imperative for the spinning industry personnel to identify the most suitable cotton fibre from a set of feasible alternatives in presence of several conflicting properties/attributes. This cotton fibre selection process can be modelled as a Multi-Criteria Decision Making (MCDM) problem. In this paper, a grey fuzzy logic-based approach is proposed for selection of the most apposite cotton fibre from 17 alternatives evaluated based on six important fibre properties. It is observed that the preference order of the top-ranked cotton fibres derived using the grey fuzzy logic approach closely matches with that attained by the past researchers which proves the application potentiality of this method in solving varying MCDM problems in textile industries.

Environmental impact assessment of man-made cellulose fibres

NARCIS (Netherlands)

Shen, L.; Worrell, E.; Patel, M.K.

2010-01-01

Man-made cellulose fibres have played an important role in the production of textile products for more than 70 years. The purpose of this study is to assess the environmental impact of man-made cellulose fibres. Life cycle assessment (LCA) was conducted for three types of fibres (i.e. Viscose, Modal

High stress monitoring of prestressing tendons in nuclear concrete vessels using fibre-optic sensors

Energy Technology Data Exchange (ETDEWEB)

Perry, M., E-mail: marcus.perry@strath.ac.uk [Institute for Energy and Environment, University of Strathclyde, 204 George Street, Glasgow G1 1XW (United Kingdom); Yan, Z.; Sun, Z.; Zhang, L. [Aston Institute of Photonic Technologies, Aston University, Birmingham B4 7ET (United Kingdom); Niewczas, P. [Institute for Energy and Environment, University of Strathclyde, 204 George Street, Glasgow G1 1XW (United Kingdom); Johnston, M. [Civil Design Group, EDF Energy, Nuclear Generation, East Kilbride G74 5PG (United Kingdom)

2014-03-15

Highlights: • We weld radiation-resistant optical fibre strain sensors to steel prestressing tendons. • We prove the sensors can survive 1300 MPa stress (80% of steel's tensile strength). • Mechanical relaxation of sensors is characterised under 1300 MPa stress over 10 h. • Strain transfer between tendon and sensor remains at 69% after relaxation. • Sensors can withstand and measure deflection of tendon around a 4.5 m bend radius. - Abstract: Maintaining the structural health of prestressed concrete nuclear containments is a key element in ensuring nuclear reactors are capable of meeting their safety requirements. This paper discusses the attachment, fabrication and characterisation of optical fibre strain sensors suitable for the prestress monitoring of irradiated steel prestressing tendons. The all-metal fabrication and welding process allowed the instrumented strand to simultaneously monitor and apply stresses up to 1300 MPa (80% of steel's ultimate tensile strength). There were no adverse effects to the strand's mechanical properties or integrity. After sensor relaxation through cyclic stress treatment, strain transfer between the optical fibre sensors and the strand remained at 69%. The fibre strain sensors could also withstand the non-axial forces induced as the strand was deflected around a 4.5 m bend radius. Further development of this technology has the potential to augment current prestress monitoring practices, allowing distributed measurements of short- and long-term prestress losses in nuclear prestressed-concrete vessels.

Removal of chromium(VI) from water and wastewater using surfactant modified coconut coir pith as a biosorbent.

Science.gov (United States)

Namasivayam, C; Sureshkumar, M V

2008-05-01

Coconut coir pith, an agricultural solid waste was used as biosorbent for the removal of chromium(VI) after modification with a cationic surfactant, hexadecyltrimethylammonium bromide. Optimum pH for Cr(VI) adsorption was found to be 2.0. Reduction of Cr(VI) to Cr(III) occurred to a slight extent during the removal. Langmuir, Freundlich and Dubinin Radushkevich (D-R) isotherms were used to model the adsorption equilibrium data and the system followed all the three isotherms. The adsorption capacity of the biosorbent was found to be 76.3 mg g(-1), which is higher or comparable to the adsorption capacity of various adsorbents reported in literature. Kinetic studies showed that the adsorption obeyed second order and Elovich model. Thermodynamic parameters such as delta G0, delta H0 and delta S0 were evaluated, indicating that the overall adsorption process was endothermic and spontaneous. Effects of foreign anions were also examined. The adsorbent was also tested for the removal of Cr(VI) from electroplating effluent.

Development of tailor-made silica fibres for TL dosimetry

International Nuclear Information System (INIS)

Bradley, D.A.; Abdul Sani, Siti F.; Alalawi, Amani I.; Jafari, S.M.; Noor, Noramaliza M.; Hairul Azhar, A.R.; Mahdiraji, Ghafour Amouzad; Tamchek, Nizam; Ghosh, S.; Paul, M.C.; Alzimami, Khalid S.; Nisbet, A.; Maah, M.J.

2014-01-01

The Ge dopant in commercially available silica optical fibres gives rise to appreciable thermoluminscence (TL), weight-for-weight offering sensitivity to MV X-rays several times that of the LiF dosimeter TLD100. The response of these fibres to UV radiation, X-rays, electrons, protons, neutrons and alpha particles, with doses from a fraction of 1 Gy up to 10 kGy, have stimulated further investigation of the magnitude of the TL signal for intrinsic and doped SiO 2 fibres. We represent a consortium effort between Malaysian partners and the University of Surrey, aimed at production of silica fibres with specific TL dosimetry applications, utilizing modified chemical vapour deposition (MCVD) doped silica–glass production and fibre-pulling facilities. The work is informed by defect and dopant concentration and various production dependences including pulling parameters such as temperature, speed and tension; the fibres also provide for spatial resolutions down to <10 µm, confronting many limitations faced in use of conventional (TL) dosimetry. Early results are shown for high spatial resolution (∼0.1 mm) single-core Ge-doped TL sensors, suited to radiotherapy applications. Preliminary results are also shown for undoped flat optical fibres of mm dimensions and Ge-B doped flat optical fibres of sub-mm dimensions, with potential for measurement of doses in medical diagnostic applications. - Highlights: • Optical fibres tailor-made for TL dosimetry. • Sensitive to diagnostic as well as therapy doses in medicine. • Preform and fibre pulling facilities. • Relative TL and EPR measurements

Fractographic observations of the microstructural characteristics of flax fibre composites

DEFF Research Database (Denmark)

Madsen, Bo; Asian, Mustafa; Lilholt, Hans

2016-01-01

Natural fibre composites possess a number of special microstructural characteristics, which need to be documented to aid in the further development of these materials. Using field emission scanning electron microscopy, fractographic observations of the microstructural characteristics of aligned f...... novel observations, measurements and interpretations to be used in the further analysis and understanding of the properties of natural fibre composites. (C) 2015 Elsevier Ltd. All rights reserved.......Natural fibre composites possess a number of special microstructural characteristics, which need to be documented to aid in the further development of these materials. Using field emission scanning electron microscopy, fractographic observations of the microstructural characteristics of aligned...... flax fibre/thermoplastic composites are presented. The findings are presented in relation to the three operational parts in composites: fibres, matrix and fibre/matrix interface. For the flax fibres, the striated structure on the fibre surface is shown to consist of cellulose macrofibrils oriented...

On the behaviour of gelled fibre suspensions in steady shear

Energy Technology Data Exchange (ETDEWEB)

Wolf, Bettina [Unilever Corporate Research, Bedford (United Kingdom); University of Nottingham, Division of Food Sciences, Loughborough (United Kingdom); White, Duncan; Melrose, John R.; Frith, William J. [Unilever Corporate Research, Bedford (United Kingdom)

2007-03-15

The shear rheological properties of suspensions of gelled agar fibres in a low viscosity Newtonian matrix fluid were investigated. Two classes of fibres, low aspect ratio fibres and high aspect ratio fibres with an aspect ratio of the order of 10 and 100 respectively were included in the investigations. For all fibre phase volumes investigated, from as low as 0.01 upwards, the flow curves are characterised by an apparent yield stress followed by shear-thinning which was independent of the fibre aspect ratio. Based on our analysis of the flow curves, we conclude that the high aspect ratio fibres behave like flexible threads in contrast to the low aspect ratio fibres whose high shear relative viscosity is successfully described by a relation for long rigid rods. These findings are supported by flow visualisation using an optical shearing stage coupled to a light microscope. (orig.)

Processing with kW fibre lasers: advantages and limits

Science.gov (United States)

Kratky, A.; Schuöcker, D.; Liedl, G.

2008-10-01

Up-to-date fibre lasers produce multi-kw radiation with an excellent beam quality. Compared to CO2-lasers, fibre lasers have relatively low operational costs and offer a very high flexibility in production due to the beam delivery with process fibres. As a consequence, fibre lasers have attracted more and more attention. On the other hand, their use in industrial applications especially in the automotive industry is still limited to a certain extent and fibre lasers haven't replaced all other laser sources till now as it could be expected. In laser cutting, the small kerf width produced by fibre lasers should be advantageous since the heated volume is smaller compared to CO2-lasers. In fact, cutting velocities are usually much higher which is also caused by the higher absorption coefficient of most metals at the wavelength emitted by fibre lasers. Nevertheless, cutting with fibre lasers of some metals - e.g. stainless steels - is restricted to a small thicknesses of approx. 5mm. The reason for this is that the surface roughness of the edges increases dramatically with the thickness of the work piece. Applications of fibre lasers include e.g. remote welding or even remote cutting of a large variety of materials with usually excellent results. Due to the excellent beam quality the aspect ratio of the weld seam in relation to the penetration depth is quite good. In the case of thin sheet metal welding such a small beam waist is beneficial - but with thicker sheet metals it is very often disadvantageous since the preparation of samples is more complicated, costs increase and requirements on clamping devices rise. In this paper, advantages and disadvantages of fibre lasers are discussed briefly. Applications of a 1.5 kW fibre laser are presented and compared to classical laser systems.

Fibre-reinforced hydrogels for tissue engineering

Science.gov (United States)

Waters, Sarah; Byrne, Helen; Chen, Mike; Dias Castilho, Miguel; Kimpton, Laura; Please, Colin; Whiteley, Jonathan

2017-11-01

Tissue engineers aim to grow replacement tissues in vitro to replace those in the body that have been damaged through age, trauma or disease. One approach is to seed cells within a scaffold consisting of an interconnected 3D-printed lattice of polymer fibres, cast in a hydrogel, and subject the construct (cell-seeded scaffold) to an applied load in a bioreactor. A key question is to understand how this applied load is distributed throughout the construct to the mechanosensitive cells. To address this, we exploit the disparate length scales (small inter-fibre spacing compared with construct dimensions). The fibres are treated as a linear elastic material and the hydrogel as a poroelastic material. We employ homogenisation theory to derive equations governing the material properties of a periodic, elastic-poroelastic composite. To validate the mobel, model solutions are compared to experimental data describing the unconfined compression of the fibre-reinforced hydrogels. The model is used to derive the bulk mechanical properties of a cylindrical construct of the composite material for a range of fibre spacings, and the local mechanical environment experienced by cells embedded within the construct is determined. Funded by the European Union Seventh Framework Programme (FP7/2007-2013).

Nanoporous ultrahigh specific surface polyacrylonitrile fibres

International Nuclear Information System (INIS)

Zhang Lifeng; Hsieh, Y-L

2006-01-01

The concept of phase separation was coupled with electrospinning to generate polyacrylonitrile (PAN) and poly(ethylene oxide) (PEO) bicomponent fibres that, upon removal of the phase-separated PEO domains, became nanoporous. Electrospinning of PAN (150 kDa) with 15-50% w/w PEO (10 kDa) at a 8% w/w total concentration in N,N-dimethylformamide produced fibres with decreasing averaged diameters from 390 to 130 nm. Evidence of phase separation between PAN and PEO in the bicomponent fibres was indicated by the characteristic PAN and PEO peaks by Fourier transform infrared (FTIR) spectroscopy and solid-state nuclear magnetic resonance (NMR) imaging, and confirmed by the co-existence of PAN cyclization and PEO melting by differential scanning calorimetry (DSC) and the presence of PEO crystalline diffraction by wide-angle x-ray scattering (WAXS). Removal of PEO by dissolution in water was confirmed by the matched mass loss to PEO fraction and the absence of PEO by FTIR and DSC. The water-treated bicomponent fibres appeared slightly larger in diameter and contained internal pores of nanometre scale. The nanoporous fibres generated from 50/50 PAN/PEO bicomponent precursor contained internal pores of a few nanometres to tens of nanometres in size and had 50% higher pore volume and 2.5-fold higher specific surface

Effects of Dietary Addition of a Low-Pectin Apple Fibre Preparation on Rats

Directory of Open Access Journals (Sweden)

Fotschki Bartosz

2014-09-01

Full Text Available The aim of this study was to scrutinise if the dietary addition of a low-pectin fibre preparation obtained from apple pomace, the by-product of apple concentrate processing, is able to favourably affect the gut metabolism, antioxidant status and blood bio-markers of the organism, as it takes place when apple fibre is present in the diet as an unprocessed ingredient. The nutritional experiment was performed on rats allocated to 2 groups of 10 animals each and fed for 2 weeks with either a control cellulose-containing diet or an experimental low-pectin apple fibre-containing diet. To induce metabolic disorders a diet rich in saturated fat and fructose was used in both diet-specific groups. The dietary apple fibre preparation (AFP significantly reduced the activity of sucrase and maltase in the mucosa of the small intestine. In the caecal digesta, the dietary AFP significantly increased bacterial α-glucosidase and α-galactosidase activity, whereas bacterial β-glucuronidase activity was significantly reduced. Also, the content of short chain fatty acids in the caecal digesta was significantly increased after the AFP supplementation. In the blood serum, the dietary AFP significantly reduced the glucose concentration, and decreased the ratio of total cholesterol to HDL cholesterol. In conclusion, the tested dietary AFP is still able to favourably affect the gut metabolism and can also ameliorate blood glucose concentration, which seems to be related to the inhibition of mucosal disaccharidase activities. However, the analysed preparation has no influence on the antioxidant status of the organism and may trigger adverse effects on cholesterol metabolism.

Fatigue damage propagation in unidirectional glass fibre reinforced composites

DEFF Research Database (Denmark)

Hansen, Jens Zangenberg; Alzamora Guzman, Vladimir Joel; Østergaard, R.C.

2012-01-01

bundles. The underlying mechanisms are examined using digital microscopy, and it is postulated that fatigue damage initiates due to stress concentrations between the backing (transverse) layer and the unidirectional layer, followed by a cyclic fretting and axial fibre debonding. This fretting mechanism......Damage progression in unidirectional glass fibre reinforced composites exposed to tension fatigue is investigated, and a quantitative explanation is given for the observed stiffness loss. The stiffness degradation during fatigue is directly related to fibre breaks in the load-carrying axial fibre...... needs further attention and understanding in order to improve the fatigue life-time of glass fibre reinforced composites....

Thermal recycling and re-manufacturing of glass fibre thermosetting composites

DEFF Research Database (Denmark)

Fraisse, Anthony; Beauson, Justine; Brøndsted, Povl

2016-01-01

The impact of using thermally recycled glass fibre in re-manufactured composites was investigated. A unidirectional glass fibre thermosetting composite laminate was manufactured. The matrix in one part of the laminate was burnt off to recover the glass fibres. These recycled glass fibres were used...

Development of Diamond-like Carbon Fibre Wheel

Institute of Scientific and Technical Information of China (English)

魏源迁; 山口勝美; 洞口巌; 竹内雅之

2004-01-01

A unique diamond-like carbon (DLC) grinding wheel was developed, in which the DLC fibres were made by rolling Al sheets coated with DLC films and aligned normally to the grinding wheel surface by laminating Al sheets together with DLC fibres. In this paper, the formation process of DLC fibres and the fabrication process of a DLC fibre wheel were investigated. Many grinding experiments were also carried out on a precision NC plane milling machine using a newly developed DLC wheel. Grinding of specimens of silicon wafers, optical glasses, quartz, granites and hardened die steel SKD11 demonstrated the capabilities of nanometer surface finish. A smooth surface with a roughness value of Ra2.5nm (Ry26nm) was achieved.

Comparison of two novel approaches to model fibre reinforced concrete

NARCIS (Netherlands)

Radtke, F.K.F.; Simone, A.; Sluys, L.J.

2009-01-01

We present two approaches to model fibre reinforced concrete. In both approaches, discrete fibre distributions and the behaviour of the fibre-matrix interface are explicitly considered. One approach employs the reaction forces from fibre to matrix while the other is based on the partition of unity

Neutral detergent fibre in piglet diets: performance and gastrointestinal implications

Directory of Open Access Journals (Sweden)

Rafael Carlos Nepomuceno

2016-04-01

Full Text Available ABSTRACT The intestinal health of piglets depends on the balance between diet, microflora and mucosal integrity. Disruption of this balance can compromise the digestive functions, leading to diarrhoeal frame and decline in performance of piglets. However, the level and type of fibre can limit digestive disorders. Thirty newly weaned piglets were used to evaluate the levels of neutral detergent fibre (NDF in diets regarding performance, pH, viscosity and concentration of short chain fatty acids of digestive contents, gastrointestinal transit time, morphology of the intestinal mucosa, weights of organs and occurrence of diarrhoea. NDF level had quadratic effect on weight gain and feed conversion ratio of piglets, estimating best results at the level of 10.4%. NDF level had no effect on the pH, viscosity and concentration of short chain fatty acids. NDF levels below 10.2% or above 13.5% reduced the transit time of digesta. There was quadratic effect on villus height in the duodenum and jejunum and in the crypt depth of jejunum. There was linear increase in stomach, caecum and colon weights and linear decrease in the occurrence of diarrhoea according to increasing NDF levels. It is concluded that levels below 10.2% and above 13.5% reduce the transit time of digesta, whereas 12.2% NDF level results in better mucosa structure of the small intestinal, with an increase in the weights of the stomach, caecum and colon and a reduction in the occurrence of diarrhoea with increasing NDF level in diets, resulting in better performance of weaned piglets with 10.4% of NDF.

Durability of fibre reinforced concrete structures

DEFF Research Database (Denmark)

Hansen, Ernst Jan De Place; Hansen, Kurt Kielsgaard

1996-01-01

The planned research will indicate, whether fibre reinforced concrete has better or worse durability than normal concrete. Durability specimens will be measured on cracked as well as uncracked specimens. Also the pore structure in the concrete will be characterized.Keywords: Fibre reinforced...... concrete, durability, pore structure, mechanical load...

Selective filling of Photonic Crystal Fibres

DEFF Research Database (Denmark)

Nielsen, Kristian; Noordegraaf, Danny; Sørensen, Thorkild

2005-01-01

A model for calculating the time necessary for filling one or more specific holes in a photonic crystal fibre is made. This model is verified for water, and its enabling potential is illustrated by a polymer application. Selective filling of the core in an air-guide photonic crystal fibre...

A Review on Pineapple Leaves Fibre and Its Composites

Directory of Open Access Journals (Sweden)

M. Asim

2015-01-01

Full Text Available Natural fibre based composites are under intensive study due to their ecofriendly nature and peculiar properties. The advantage of natural fibres is their continuous supply, easy and safe handling, and biodegradable nature. Although natural fibres exhibit admirable physical and mechanical properties, it varies with the plant source, species, geography, and so forth. Pineapple leave fibre (PALF is one of the abundantly available wastes materials of Malaysia and has not been studied yet as it is required. A detailed study of chemical, physical, and mechanical properties will bring out logical and reasonable utilization of PALF for various applications. From the socioeconomic prospective, PALF can be a new source of raw material to the industries and can be potential replacement of the expensive and nonrenewable synthetic fibre. However, few studies on PALF have been done describing the interfacial adhesion between fibres and reinforcement compatibility of fibre but a detailed study on PALF properties is not available. In this review, author covered the basic information of PALF and compared the chemical, physical, and mechanical properties with other natural fibres. Furthermore, it summarizes the recent work reported on physical, mechanical, and thermal properties of PALF reinforced polymer composites with its potential applications.

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.

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.

Investigation on effect of fibre hybridization and orientation on ...

Indian Academy of Sciences (India)

2017-07-25

Jul 25, 2017 ... for fibres to assess their efficiency. The first ... alternative to flax spun yarns. Bledzki et al ... Natural fibre composite are renewable, light in weight with ..... absorbs more energy due to hybridization of abaca and neem fibres.

Steel fibre corrosion in cracks:durability of sprayed concrete

OpenAIRE

Nordström, Erik

2000-01-01

Steel fibre reinforced sprayed concrete is common practice for permanent linings in underground construction. Today there is a demand on "expected technical service life" of 120 years. Thin steel fibres could be expected to discontinue carrying load fast with a decrease of fibre diameter caused by corrosion, especially in cracks. The thesis contains results from inspections on existing sprayed concrete structures and a literature review on corrosion of steel fibres in cracked concrete. To stu...

Advanced materials and techniques for fibre-optic sensing

Science.gov (United States)

Henderson, Philip J.

2014-06-01

Fibre-optic monitoring systems came of age in about 1999 upon the emergence of the world's first significant commercialising company - a spin-out from the UK's collaborative MAST project. By using embedded fibre-optic technology, the MAST project successfully measured transient strain within high-performance composite yacht masts. Since then, applications have extended from smart composites into civil engineering, energy, military, aerospace, medicine and other sectors. Fibre-optic sensors come in various forms, and may be subject to embedment, retrofitting, and remote interrogation. The unique challenges presented by each implementation require careful scrutiny before widespread adoption can take place. Accordingly, various aspects of design and reliability are discussed spanning a range of representative technologies that include resonant microsilicon structures, MEMS, Bragg gratings, advanced forms of spectroscopy, and modern trends in nanotechnology. Keywords: Fibre-optic sensors, fibre Bragg gratings, MEMS, MOEMS, nanotechnology, plasmon.

Insertion of optic fibre for CMS

CERN Multimedia

Maximilien Brice

2003-01-01

The MicroJET system uses high pressure to carefully put the optical fibres into their protective tubes. These fibres are vital for rapid data transfer, but are also very delicate and, if damanged, may not work at the required efficiency. Similiar methods are used to install cables for the telecommunications industry.

Endovenous laser ablation of the great saphenous vein using a bare fibre versus a tulip fibre: a randomised clinical trial.

Science.gov (United States)

Vuylsteke, M E; Thomis, S; Mahieu, P; Mordon, S; Fourneau, I

2012-12-01

This clinical trial aimed to evaluate the clinical results of the use of a tulip fibre versus the use of a bare fibre for endovenous laser ablation. In a multicentre prospective randomised trial 174 patients were randomised for the treatment of great saphenous vein reflux. A duplex scan was scheduled 1 month, 6 months and 1 year postoperatively. Ecchymosis was measured on the 5th postoperative day. In addition, pain, analgesics requirement, postoperative quality of life (CIVIQ 2) and patient satisfaction rate were noted. Patients treated with a tulip fibre had significantly less postoperative ecchymosis (0.04 vs. 0.21; p tulip fibre for EVLA of the great saphenous vein results, when compared with the use of a bare fibre, in equal occlusion rates at 1 year but causes less postoperative ecchymosis and pain and in a better postoperative quality of life. Copyright © 2012 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

Influence of accompanying substances of hemp fibres on their electric resistance

Directory of Open Access Journals (Sweden)

Pejić Biljana

2006-01-01

Full Text Available Hemp fibres belong to the group of natural, cellulose bast fibres. These fibres have exceptional properties such as: antimicrobial effect, absence of allergy effect, extraordinary sorption properties, good electro-physical properties (small static electricity in regard to other cellulose fibres as well as high values of breaking strength (the natural fibre with the highest strength. However, hemp fibres have some defects: heterogeneous chemical composition, large quantity of accompanying substances (lignin pectins, waxes and unsatisfactory fineness and eveness. It is possible to a great extent to eliminate or reduce, the defects of hemp fibres by of appropriate modification treatments. In order to determine the appropriate modification treatment of hemp fibres, the dependences between the chemical composition, fineness and electric resistance of hemp fibres were presented in this paper. In the experimental part of the paper, by the application of a procedure for the determination of the chemical composition, the accompanying supstances of hemp fibres were gradually removed. After each phase some fibrous substrates were separated. After that the fineness and electric resistance were determined. This experiment was conducted in order to define the influence of each component of hemp fibres on the fineness and electric resistance. In this paper, hemp fibres were modified by an aqueous solution of sodium hydroxide, under different conditions of modification. The influence of modification conditions on the fineness and electric resistance were studied.

Ion irradiation effects on tensile properties of carbon fibres

International Nuclear Information System (INIS)

Kurumada, A.; Ishihara, M.; Baba, S.; Aihara, J.

2004-01-01

Carbon/carbon composite materials have high thermal conductivity and excellent mechanical properties at high temperatures. They have been used as structural materials at high temperatures in fission and experimental fusion reactors. The changes in the microstructures and the mechanical properties due to irradiation damage must be measured for the safety design and the life assessment of the materials. The purpose of this study is to obtain a basic knowledge of the development of new carbon composite materials having high thermal conductivity and excellent resistance to irradiation damage. Five kinds of carbon fibres were selected, including a vapour growth carbon fibre (VGCF; K1100X), a polyacrylonitrile-based fibre (PAN; M55JB by Toray Corp.), two meso-phase pitch-based fibres (YS-15-60S and YS-70-60S by Nippon Graphite Fiber Corp.) and a pitch-based fibre (K13C2U by Mitsubishi Chemical Co.). They were irradiated by high-energy carbon, nickel and argon ions. Irradiation damages in the carbon fibres are expected to be uniform across the cross-section, as the diameters of the carbon fibres are about 20 μm and are sufficiently smaller than the ranges of ions. The cross-sectional areas increased due to ion irradiation, with the exception of the K1100X of VGCF. One of the reasons for the increases is the swelling of carbon basal planes due to lattice defects in the graphite interlayer. The tensile strengths and the Young's moduli decreased due to ion irradiation except for the K1100X of VGCF and the YS-15-60S of meso-phase pitch-based fibres. One of the reasons for the decreases is thought to be that the microstructures of carbon fibres are damaged in the axial direction, as ions were irradiated vertically with respect to the longitudinal direction of carbon fibres. The results of this study indicate that the VGCF and the meso-phase pitch-based carbon fibres could be useful as reinforcement fibres of new carbon composite materials having high thermal conductivity and