WorldWideScience

Sample records for nanocluster composite fabricated

  1. Fabrication and modification of metal nanocluster composites using ion and laser beams

    International Nuclear Information System (INIS)

    Haglund, R.F. Jr.; Osborne, D.H. Jr.; Magruder, R.H. III; White, C.W.; Zuhr, R.A.; Townsend, P.D.; Hole, D.E.; Leuchtner, R.E.

    1994-12-01

    Metal nanocluster composites have attractive properties for applications in nonlinear optics. However, traditional fabrication techniques -- using melt-glass substrates -- are severely constrained by equilibrium thermodynamics and kinetics. This paper describes the fabrication of metal nanoclusters in both crystalline and glassy hosts by ion implantation and pulsed laser deposition. The size and size distribution of the metal nanoclusters can be modified by controlling substrate temperature during implantation, by subsequent thermal annealing, or by laser irradiation. The authors have characterized the optical response of the composites by absorption and third-order nonlinear-optical spectroscopies; electron and scanning-probe microscopies have been used to benchmark the physical characteristics of the composites. The outlook for controlling the structure and nonlinear optical response properties of these nanophase materials appears increasingly promising

  2. Nonlinear optical properties of Cu nanocluster composite fabricated by 180 keV ion implantation

    Science.gov (United States)

    Wang, Y. H.; Wang, Y. M.; Lu, J. D.; Ji, L. L.; Zang, R. G.; Wang, R. W.

    2009-11-01

    Metal nanocluster composite glass prepared by 180 keV Cu ions into silica with dose of 5×10 16 ions/cm 2 has been studied. The microstructural properties of the nanoclusters has been verified by optical absorption spectra and transmission electron microscopy (TEM). Third-order nonlinear optical properties of the nanoclusters were measured at 1064 and 532 nm excitations using Z-scan technique. The nonlinear refraction index, nonlinear absorption coefficient, and the real and imaginary parts of the third-order nonlinear susceptibility were deduced. Results of the investigation of nonlinear refraction by the off-axis Z-scan configuration were presented and the mechanisms responsible for the nonlinear response were discussed. Third-order nonlinear susceptibility χ(3) of this kind of sample was determined to be 8.7×10 -8 esu at 532 nm and 6.0×10 -8 esu at 1064 nm, respectively.

  3. Fabrication of highly catalytic silver nanoclusters/graphene oxide nanocomposite as nanotag for sensitive electrochemical immunoassay

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jiamian; Wang, Xiuyun; Wu, Shuo, E-mail: wushuo@dlut.edu.cn; Song, Jie; Zhao, Yanqiu; Ge, Yanqiu; Meng, Changgong

    2016-02-04

    Silver nanoclusters and graphene oxide nanocomposite (AgNCs/GRO) is synthesized and functionalized with detection antibody for highly sensitive electrochemical sensing of carcinoembryonic antigen (CEA), a model tumor marker involved in many cancers. AgNCs with large surface area and abundant amount of low-coordinated sites are synthesized with DNA as template and exhibit high catalytic activity towards the electrochemical reduction of H{sub 2}O{sub 2}. GRO is employed to assemble with AgNCs because it has large specific surface area, super electronic conductivity and strong π-π stacking interaction with the hydrophobic bases of DNA, which can further improve the catalytic ability of the AgNCs. Using AgNCs/GRO as signal amplification tag, an enzyme-free electrochemical immunosensing protocol is designed for the highly sensitive detection of CEA on the capture antibody functionalized immunosensing interface. Under optimal conditions, the designed immunosensor exhibits a wide linear range from 0.1 pg mL{sup −1} to 100 ng mL{sup −1} and a low limit of detection of 0.037 pg mL{sup −1}. Practical sample analysis reveals the sensor has good accuracy and reproducibility, indicating the great application prospective of the AgNCs/GRO in fabricating highly sensitive immunosensors, which can be extended to the detection of various kinds of low abundance disease related proteins. - Highlights: • An enzyme-free electrochemical immunosensor is reported for detecting proteins. • A silver nanocluster/graphene oxide composite is synthesized as nanotag. • The nanotags exhibit highly catalytic activity to the electro-reduction of H{sub 2}O{sub 2}. • The as-fabricated immunosensor could detect protein in serum samples.

  4. Highly fluorescent silver nanoclusters in alumina-silica composite optical fiber

    Energy Technology Data Exchange (ETDEWEB)

    Halder, A.; Chattopadhyay, R.; Majumder, S.; Paul, M. C.; Das, S.; Bhadra, S. K., E-mail: skbhadra@cgcri.res.in [Fiber Optics and Photonics Division, CSIR-Central Glass and Ceramic Research Institute, 196, Raja S. C. Mullick Road, Kolkata 700032 (India); Bysakh, S.; Unnikrishnan, M. [Material Characterization Division, CSIR-Central Glass and Ceramic Research Institute, 196, Raja S. C. Mullick Road, Kolkata 700032 (India)

    2015-01-05

    An efficient visible fluorescent optical fiber embedded with silver nanoclusters (Ag-NCs) having size ∼1 nm, uniformly distributed in alumina-silica composite core glass, is reported. Fibers are fabricated in a repetitive controlled way through modified chemical vapour deposition process associated with solution doping technique. Fibers are drawn from the transparent preforms by conventional fiber drawing process. Structural characteristics of the doped fibers are studied using transmission electron microscopy and electron probe micro analysis. The oxidation state of Ag within Ag-NCs is investigated by X-ray photo electron spectroscopy. The observed significant fluorescence of the metal clusters in fabricated fibers is correlated with electronic model. The experimentally observed size dependent absorption of the metal clusters in fabricated fibers is explained with the help of reported results calculated by ab-initio density functional theory. These optical fibers may open up an opportunity of realizing tunable wavelength fiber laser without the help of rare earth elements.

  5. Multilayered nanoclusters of platinum and gold: insights on electrodeposition pathways, electrocatalysis, surface and bulk compositional properties

    CSIR Research Space (South Africa)

    Mkwizu, TS

    2013-06-01

    Full Text Available Electrochemical, surface and bulk compositional properties of multilayered nanoclusters of Pt and Au, electrochemically deposited on glassy carbon under conditions involving sequential surface–limited redox–replacement reactions (performed at open...

  6. Fluorescent Pressure Response of Protein-Nanocluster Polymer Composites

    Science.gov (United States)

    2016-05-01

    nanoclusters exhibit fluorescent effects similarly to semiconductor-based quantum dots and are not nearly as toxic due to their lack of heavy metals .7...Strongly emissive individual DNA -encapsulated Ag nanoclusters as single molecule fluorophores. PNAS 31. 2007:12616–12621. 5. Wang F, Tan WB

  7. Luminescent golden silk and fabric through in situ chemically coating pristine-silk with gold nanoclusters.

    Science.gov (United States)

    Zhang, Pu; Lan, Jing; Wang, Yi; Xiong, Zu Hong; Huang, Cheng Zhi

    2015-01-01

    Silk is an excellent natural material and has been used for a variety of applications. Modification of the pristine silk is usually needed depending on the intended purpose. The technical treatments involved in the modification not only should be easy, rapid, environmentally friendly, and cheap but should also retain the features of the pristine silk. Herein, we demonstrate that luminescent silk and fabric can be produced through nanotechnology. The surface of the natural silk fiber is chemically coated with luminescent gold nanoclusters (AuNCs) composed of tens to hundreds of Au atoms through a redox reaction between the protein-based silk and an Au salt precursor. The luminescent silk coated with AuNCs (called golden silk) possesses good optical properties, including a relatively long wavelength emission, high quantum yields, a long fluorescent lifetime, and photostability. Moreover, golden silk prepared this way has better mechanical properties than pristine silk, is better able to inhibit UV, and has lower toxicity in vitro. This work not only provides an effective strategy for in situ preparation of luminescent metal nanoclusters on a solid substrate but also paves the way for large-scale and industrialized production of novel silk-based materials or fabrics through nanotechnology. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Antibacterial silver nanocluster/silica composite coatings on stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Ferraris, M.; Perero, S. [Politecnico di Torino, Department of Applied Science and Technology, Torino, C.so Duca degli Abruzzi 24, I-10129 (Italy); Ferraris, S., E-mail: sara.ferraris@polito.it [Politecnico di Torino, Department of Applied Science and Technology, Torino, C.so Duca degli Abruzzi 24, I-10129 (Italy); Miola, M.; Vernè, E. [Politecnico di Torino, Department of Applied Science and Technology, Torino, C.so Duca degli Abruzzi 24, I-10129 (Italy); Skoglund, S. [KTH Royal Institute of Technology, Div. Surface and Corrosion Science, Dr. Kristinas v. 51, SE-100 44 (Sweden); Blomberg, E. [KTH Royal Institute of Technology, Div. Surface and Corrosion Science, Dr. Kristinas v. 51, SE-100 44 (Sweden); SP Technical Research Institute of Sweden, Chemistry, Materials and Surfaces, P.O. Box 5607, SE-114 86 Stockholm (Sweden); Odnevall Wallinder, I. [KTH Royal Institute of Technology, Div. Surface and Corrosion Science, Dr. Kristinas v. 51, SE-100 44 (Sweden)

    2017-02-28

    Highlights: • A silver nanocluster-silica composite coating sputter-deposited onto stainless steel. • Good adhesion and resistance upon cleaning with NaOH, H{sub 2}SO{sub 4} and detergents. • Low release of silver ions and no release as silver nanoparticles. • Good antibacterial activity against S. aureus even after heating to 450 °C. • Good antibacterial activity shown during cheese production. - Abstract: A coating made of silver nanocluster/silica composites has been deposited, via a radio frequency (RF) co-sputtering technique, for the first time onto stainless steel (AISI 304L) with the aim to improve its antibacterial properties. Different thermal treatments after coating deposition have been applied in order to optimize the coating adhesion, cohesion and its antibacterial properties. Its applicability has been investigated at realistic conditions in a cheese production plant. The physico-chemical characteristics of the coatings have been analyzed by means of different bulk and surface analytical techniques. Field emission scanning electron microscopy (FESEM), X-ray Photoelectron Spectroscopy (XPS), contact angle measurements and atomic force microscopy (AFM) were employed to assess coating morphology, composition, surface roughness, wetting properties, size and local distribution of the nanoparticles within the coating. Tape tests were used to determine the adhesion/cohesion properties of the coating. The amount and time-dependence of released silver in solutions of acetic acid, artificial water, artificial tap water and artificial milk were determined by means of Atomic Absorption Spectroscopy (AAS). The antibacterial effect of the coating was evaluated at different experimental conditions using a standard bacterial strain of Staphylococcus aureus in compliance with National Committee for Clinical Laboratory Standards (NCCLS) and AATCC 147 standards. The Ahearn test was performed to measure the adhesion of bacteria to the coated stainless steel

  9. Antibacterial silver nanocluster/silica composite coatings on stainless steel

    International Nuclear Information System (INIS)

    Ferraris, M.; Perero, S.; Ferraris, S.; Miola, M.; Vernè, E.; Skoglund, S.; Blomberg, E.; Odnevall Wallinder, I.

    2017-01-01

    Highlights: • A silver nanocluster-silica composite coating sputter-deposited onto stainless steel. • Good adhesion and resistance upon cleaning with NaOH, H 2 SO 4 and detergents. • Low release of silver ions and no release as silver nanoparticles. • Good antibacterial activity against S. aureus even after heating to 450 °C. • Good antibacterial activity shown during cheese production. - Abstract: A coating made of silver nanocluster/silica composites has been deposited, via a radio frequency (RF) co-sputtering technique, for the first time onto stainless steel (AISI 304L) with the aim to improve its antibacterial properties. Different thermal treatments after coating deposition have been applied in order to optimize the coating adhesion, cohesion and its antibacterial properties. Its applicability has been investigated at realistic conditions in a cheese production plant. The physico-chemical characteristics of the coatings have been analyzed by means of different bulk and surface analytical techniques. Field emission scanning electron microscopy (FESEM), X-ray Photoelectron Spectroscopy (XPS), contact angle measurements and atomic force microscopy (AFM) were employed to assess coating morphology, composition, surface roughness, wetting properties, size and local distribution of the nanoparticles within the coating. Tape tests were used to determine the adhesion/cohesion properties of the coating. The amount and time-dependence of released silver in solutions of acetic acid, artificial water, artificial tap water and artificial milk were determined by means of Atomic Absorption Spectroscopy (AAS). The antibacterial effect of the coating was evaluated at different experimental conditions using a standard bacterial strain of Staphylococcus aureus in compliance with National Committee for Clinical Laboratory Standards (NCCLS) and AATCC 147 standards. The Ahearn test was performed to measure the adhesion of bacteria to the coated stainless steel surface

  10. Formation of functionalized nanoclusters by solvent evaporation and their effect on the physicochemical properties of dental composite resins.

    Science.gov (United States)

    Rodríguez, Henry A; Giraldo, Luis F; Casanova, Herley

    2015-07-01

    The aim of this work was to study the effect of silica nanoclusters (SiNC), obtained by a solvent evaporation method and functionalized by 3-methacryloxypropyltrimethoxysilane (MPS) and MPS+octyltrimethoxysilane (OTMS) (50/50wt/wt), on the rheological, mechanical and sorption properties of urethane dimethylacrylate (UDMA)/triethylenglycol dimethacrylate (TEGDMA) (80/20wt/wt) resins blend. Silica nanoparticles (SiNP) were silanized with MPS or MPS+OTMS (50/50wt/wt) and incorporated in an UDMA-isopropanol mix to produce functionalized silica nanoclusters after evaporating the isopropanol. The effect of functionalized SiNC on resins rheological properties was determined by large and small deformation tests. Mechanical, thermal, sorption and solubility properties were evaluated for composite materials. The UDMA/TEGDMA (80/20wt/wt) resins blend with added SiNC (ca. 350nm) and functionalized with MPS showed a Newtonian flow behavior associated to their spheroidal shape, whereas the resins blend with nanoclusters silanized with MPS+OTMS (50/50wt/wt) (ca. 400nm) showed a shear-thinning behavior due to nanoclusters irregular shape. Composite materials prepared with bare silica nanoclusters showed lower compressive strength than functionalized silica nanoclusters. MPS functionalized nanoclusters showed better mechanical properties but higher water sorption than functionalized nanoclusters with both silane coupling agents, MPS and OTMS. The solvent evaporation method applied to functionalized nanoparticles showed to be an alternative way to the sinterization method for producing nanoclusters, which improved some dental composite mechanical properties and reduced water sorption. The shape of functionalized silica nanoclusters showed to have influence on the rheological properties of SiNC resin suspensions and the mechanical and sorption properties of light cured composites. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  11. Compositional evolution of Pd-based nanoclusters under thermal annealing in ion implanted SiO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Mattei, G. E-mail: mattei@padova.infm.it; Battaglin, G.; Bello, V.; Cattaruzza, E.; De Julian, C.; De Marchi, G.; Maurizio, C.; Mazzoldi, P.; Parolin, M.; Sada, C

    2004-06-01

    Sequential ion implantation has been used to synthesize Pd-based alloy nanoclusters in SiO{sub 2}. Three systems have been investigated (PdCu, PdAg and PdFe) in terms of nanocluster formation and stability under thermal annealing. In particular, we focused on the role played by the annealing atmosphere. A comparison is made with similar alloy-based systems obtained by sequential ion implantation in silica of Au-Ag or Au-Cu followed by annealing under similar conditions. Strong similarities have been found in the compositional evolution of Pd-based and Au-based nanoclusters.

  12. Facile Fabrication of a Gold Nanocluster-Based Membrane for the Detection of Hydrogen Peroxide

    Directory of Open Access Journals (Sweden)

    Pu Zhang

    2016-07-01

    Full Text Available In this work, we present a simple and rapid method to synthesize red luminescent gold nanoclusters (AuNCs with high quantum yield (QY, ~16%, excellent photostability and biocompatibility. Next, we fabricated a solid membrane by loading the as-prepared AuNCs in an agar matrix. Different from nanomaterials dispersed in solution, the AuNCs-based solid membrane has distinct advantages including convenience of transportation, while still maintaining strong red luminescence, and relatively long duration storage without aggregation. Taking hydrogen peroxide (H2O2 as a typical example, we then employed the AuNCs as a luminescent probe and investigated their sensing performance, either in solution phase or on a solid substrate. The detection of H2O2 could be achieved in wide concentration ranges over 805 nM–1.61 mM and 161 μM–19.32 mM in solution and on a solid membrane, respectively, with limits of detection (LOD of 80 nM and 20 μM. Moreover, the AuNCs-based membrane could also be used for visual detection of H2O2 in the range of 0–3.22 mM. In view of the convenient synthesis route and attractive luminescent properties, the AuNCs-based membrane presented in this work is quite promising for applications such as optical sensing, fluorescent imaging, and photovoltaics.

  13. Fabrication of highly catalytic silver nanoclusters/graphene oxide nanocomposite as nanotag for sensitive electrochemical immunoassay.

    Science.gov (United States)

    Wang, Jiamian; Wang, Xiuyun; Wu, Shuo; Song, Jie; Zhao, Yanqiu; Ge, Yanqiu; Meng, Changgong

    2016-02-04

    Silver nanoclusters and graphene oxide nanocomposite (AgNCs/GRO) is synthesized and functionalized with detection antibody for highly sensitive electrochemical sensing of carcinoembryonic antigen (CEA), a model tumor marker involved in many cancers. AgNCs with large surface area and abundant amount of low-coordinated sites are synthesized with DNA as template and exhibit high catalytic activity towards the electrochemical reduction of H2O2. GRO is employed to assemble with AgNCs because it has large specific surface area, super electronic conductivity and strong π-π stacking interaction with the hydrophobic bases of DNA, which can further improve the catalytic ability of the AgNCs. Using AgNCs/GRO as signal amplification tag, an enzyme-free electrochemical immunosensing protocol is designed for the highly sensitive detection of CEA on the capture antibody functionalized immunosensing interface. Under optimal conditions, the designed immunosensor exhibits a wide linear range from 0.1 pg mL(-1) to 100 ng mL(-1) and a low limit of detection of 0.037 pg mL(-1). Practical sample analysis reveals the sensor has good accuracy and reproducibility, indicating the great application prospective of the AgNCs/GRO in fabricating highly sensitive immunosensors, which can be extended to the detection of various kinds of low abundance disease related proteins. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Fabrication of peptide stabilized fluorescent gold nanocluster/graphene oxide nanocomplex and its application in turn-on detection of metalloproteinase-9.

    Science.gov (United States)

    Nguyen, Phuong-Diem; Cong, Vu Thanh; Baek, Changyoon; Min, Junhong

    2017-03-15

    This study introduces the double-ligands stabilizing gold nanoclusters and the fabrication of gold nanocluster/graphene nanocomplex as a "turn-on" fluorescent probe for the detection of cancer-related enzyme matrix metalloproteinase-9. A facile, one-step approach was developed for the synthesis of fluorescent gold nanoclusters using peptides and mercaptoundecanoic acid as co-templating ligands. The peptide was designed to possess a metalloproteinase-9 cleavage site and to act not only as a stabilizer but also as a targeting ligand for the enzyme detection. The prepared gold nanoclusters show an intense red fluorescence with a broad adsorption spectrum. In the presence of the enzyme, due to the excellent quenching properties and the negligible background of graphene oxide, the developed peptide-gold nanocluster/graphene nanocomplex yielded an intense "turn-on" fluorescent response, which strongly correlated with the enzyme concentration. The limit of detection of the nanocomplex was 0.15nM. The sensor was successfully applied for "turn-on" detection of metalloproteinase-9 secreted from human breast adenocarcinoma MCF-7 cells with high sensitivity, selectivity, significant improvement in terms of detection time and simplicity. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Pulse Laser Deposition Fabricating Gold Nanoclusters on a Glassy Carbon Surface for Nonenzymatic Glucose Sensing.

    Science.gov (United States)

    Shu, Honghui; Chang, Gang; Wang, Zhiqiang; Li, Pai; Zhang, Yuting; He, Yunbin

    2015-01-01

    A One-step technique for depositing gold nanoclusters (GNCs) onto the surface of a glassy carbon (GC) plate was developed by using pulse laser deposition (PLD) with appropriate process parameters. The method is simple and clean without using any templates, surfactants, or stabilizers. The experimental factors (pulse laser number and the pressure of inert gas (Ar)) that affect the morphology and structure of GNCs, and thus affect the electrocatalytic oxidation performance towards glucose were systematically investigated by means of transmission electron microscopy (TEM) and electrochemical methods (cyclic voltammograms (CV) and chronoamperometry methods). The GC electrode modified by GNCs exhibited a rapid response time (about 2 s), a broad linear range (0.1 to 20 mM), and good stability. The sensitivity was estimated to be 31.18 μA cm(-2) mM(-1) (vs. geometric area), which is higher than that of the Au bulk electrode. It has a good resistance to the common interfering species, such as ascorbic acid (AA), uric acid (UA) and 4-acetaminophen (AP). Therefore, this work has demonstrated a simple and effective sensing platform for the nonenzymatic detection of glucose, and can be used as a new material for a novel non-enzymatic glucose sensor.

  16. Natural fabric sandwich laminate composites: development and ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 40; Issue 1 ... Natural fabrics; jute; linen; sandwich laminate; mechanical properties; fractographic analysis. ... In this work, eco-friendly natural fabric sandwich laminate (NFSL) composites are formulated using jute and linen-fabric-reinforced epoxy with different layer ...

  17. Application of spacer fabrics in composite production

    OpenAIRE

    Mecit, Diren; , Arzu Marmaralı

    2012-01-01

    Developments in the field of textile reinforced composites have been increasing in the last several years. In the first developed composite materials, fibers were used as reinforcement element. Textile materials such as staple fibers, bands, filament yarns, cables and two dimensional textiles are widely used as reinforcement elements in composite materials. Spacer fabrics consist of two outer surfaces and a connection layer between those outer surfaces. Spacer fabrics can be classified in the...

  18. Application of spacer fabrics in composite production

    OpenAIRE

    Mecit, Diren; -, Arzu Marmaralı

    2014-01-01

    Developments in the field of textile reinforced composites have been increasing in the last several years. In the first developed composite materials, fibers were used as reinforcement element. Textile materials such as staple fibers, bands, filament yarns, cables and two dimensional textiles are widely used as reinforcement elements in composite materials. Spacer fabrics consist of two outer surfaces and a connection layer between those outer surfaces. Spacer fabrics can be classified in the...

  19. Fabrication and in vitro characterization of gadolinium-based nanoclusters for simultaneous drug delivery and radiation enhancement

    Science.gov (United States)

    Yoo, Shannon S.; Guo, Linghong; Sun, Xuejun; Shaw, Andrew R.; Yuan, Zhipeng; Löbenberg, Raimar; Roa, Wilson H.

    2016-09-01

    We report the synthesis of a gadolinium hydroxide (Gd(OH)3) nanorod based doxorubicin (Dox) delivery system that can enhance both magnetic resonance imaging contrast and radiation sensitivity. A simple and cost effective wet-chemical method was utilized in the presence of manganese (Mn) ions and Dox to produce the Gd(OH)3:Mn·Dox nanocluster structure. The Gd(OH)3:Mn·Dox nanocluster was composed of Mn-doped Gd(OH)3 nanorods arranged in parallel with Dox as a linker molecule between the adjacent nanorods. No other studies have utilized Dox as both the linker and therapeutic molecule in a nanostructure to date. The Gd(OH)3 nanorod is reported to have no significant cellular or in vivo toxicity, which makes it an ideal base material for this biomedical application. The Gd(OH)3:Mn·Dox nanocluster exhibited paramagnetic behavior and was stable in a colloidal solution. The nanocluster also enabled high Dox loading capacity and specifically released Dox in a sustained and pH-dependent manner. The positively charged Gd(OH)3:Mn·Dox nanoclusters were readily internalized into MDA-MB-231 breast cancer cells via endocytosis, which resulted in intracellular release of Dox. The released Dox in cells was effective in conferring cytotoxicity and inhibiting proliferation of cancer cells. Furthermore, a synergistic anticancer effect could be observed with radiation treatment. Overall, the Gd(OH)3:Mn·Dox nanocluster drug delivery system described herein may have potential utility in clinics as a multifunctional theranostic nanoparticle with combined benefits in both diagnosis and therapy in the management of cancer.

  20. Chemical, mechanical and antibacterial properties of silver nanocluster/silica composite coated textiles for safety systems and aerospace applications

    Energy Technology Data Exchange (ETDEWEB)

    Ferraris, S., E-mail: sara.ferraris@polito.it [Politecnico di Torino, Torino, C.so Duca degli Abruzzi 24, 10129 (Italy); Perero, S.; Miola, M.; Vernè, E. [Politecnico di Torino, Torino, C.so Duca degli Abruzzi 24, 10129 (Italy); Rosiello, A.; Ferrazzo, V.; Valletta, G. [Aero Sekur S.p.A., Aprilia, via delle Valli 46, 04011 (Italy); Sanchez, J.; Ohrlander, M. [Bactiguard AB, Biblioteksgatan 25, Box 5070, SE-10242, Stockholm (Sweden); Tjörnhammar, S.; Fokine, M.; Laurell, F. [KTH Royal Institute of Technology, Department of Applied Physics, Roslagstullsbacken 21, SE-106 91 Laserphysics, Stockholm (Sweden); Blomberg, E. [KTH Royal Institute of Technology, Div. Surface and Corrosion Science, Drottning Kristinas väg 51, SE-100 44, Stockholm (Sweden); SP Technical Research Institute of Sweden, Chemistry, Materials and Surfaces, Box 5607, SE-114 86, Stockholm (Sweden); Skoglund, S.; Odnevall Wallinder, I. [KTH Royal Institute of Technology, Div. Surface and Corrosion Science, Drottning Kristinas väg 51, SE-100 44, Stockholm (Sweden); Ferraris, M. [Politecnico di Torino, Torino, C.so Duca degli Abruzzi 24, 10129 (Italy)

    2014-10-30

    Highlights: • Silver nanoclusters-silica composite coatings were deposited on textiles. • Textiles for NBC protection suites and for aerospace applications were considered. • The coating process conferred all textiles a good antibacterial activity. • The coating does not alter the properties of bare textiles. - Abstract: This work describes the chemical, mechanical and antibacterial properties of a novel silver nanocluster/silica composite coating, obtained by sputtering, on textiles for use in nuclear bacteriological and chemical (NBC) protection suites and for aerospace applications. The properties of the coated textiles were analyzed in terms of surface morphology, silver concentration and silver release in artificial sweat and synthetic tap water, respectively. No release of silver nanoparticles was observed at given conditions. The water repellency, permeability, flammability and mechanical resistance of the textiles before and after sputtering demonstrated that the textile properties were not negatively affected by the coating. The antibacterial effect was evaluated at different experimental conditions using a standard bacterial strain of Staphylococcus aureus and compared with the behavior of uncoated textiles. The coating process conferred all textiles a good antibacterial activity. Optimal deposition conditions were elaborated to obtain sufficient antibacterial action without altering the aesthetical appearance of the textiles. The antibacterial coating retained its antibacterial activity after one cycle in a washing machine only for the Nylon based textile.

  1. Chemical, mechanical and antibacterial properties of silver nanocluster/silica composite coated textiles for safety systems and aerospace applications

    International Nuclear Information System (INIS)

    Ferraris, S.; Perero, S.; Miola, M.; Vernè, E.; Rosiello, A.; Ferrazzo, V.; Valletta, G.; Sanchez, J.; Ohrlander, M.; Tjörnhammar, S.; Fokine, M.; Laurell, F.; Blomberg, E.; Skoglund, S.; Odnevall Wallinder, I.; Ferraris, M.

    2014-01-01

    Highlights: • Silver nanoclusters-silica composite coatings were deposited on textiles. • Textiles for NBC protection suites and for aerospace applications were considered. • The coating process conferred all textiles a good antibacterial activity. • The coating does not alter the properties of bare textiles. - Abstract: This work describes the chemical, mechanical and antibacterial properties of a novel silver nanocluster/silica composite coating, obtained by sputtering, on textiles for use in nuclear bacteriological and chemical (NBC) protection suites and for aerospace applications. The properties of the coated textiles were analyzed in terms of surface morphology, silver concentration and silver release in artificial sweat and synthetic tap water, respectively. No release of silver nanoparticles was observed at given conditions. The water repellency, permeability, flammability and mechanical resistance of the textiles before and after sputtering demonstrated that the textile properties were not negatively affected by the coating. The antibacterial effect was evaluated at different experimental conditions using a standard bacterial strain of Staphylococcus aureus and compared with the behavior of uncoated textiles. The coating process conferred all textiles a good antibacterial activity. Optimal deposition conditions were elaborated to obtain sufficient antibacterial action without altering the aesthetical appearance of the textiles. The antibacterial coating retained its antibacterial activity after one cycle in a washing machine only for the Nylon based textile

  2. Composite fabrication via resin transfer molding technology

    Energy Technology Data Exchange (ETDEWEB)

    Jamison, G.M.; Domeier, L.A.

    1996-04-01

    The IMPReS (Integrated Modeling and Processing of Resin-based Structures) Program was funded in FY95 to consolidate, evaluate and enhance Sandia`s capabilities in the design and fabrication of composite structures. A key driver of this and related programs was the need for more agile product development processes and for model based design and fabrication tools across all of Sandia`s material technologies. A team of polymer, composite and modeling personnel was assembled to benchmark Sandia`s existing expertise in this area relative to industrial and academic programs and to initiate the tasks required to meet Sandia`s future needs. RTM (Resin Transfer Molding) was selected as the focus composite fabrication technology due to its versatility and growing use in industry. Modeling efforts focused on the prediction of composite mechanical properties and failure/damage mechanisms and also on the uncured resin flow processes typical of RTM. Appropriate molds and test composites were fabricated and model validation studies begun. This report summarizes and archives the modeling and fabrication studies carried out under IMPReS and evaluates the status of composite technology within Sandia. It should provide a complete and convenient baseline for future composite technology efforts within Sandia.

  3. Heterostructure of Au nanocluster tipping on a ZnS quantum rod: controlled synthesis and novel luminescence.

    Science.gov (United States)

    Tian, Yang; Wang, Ligang; Yu, Shanshan; Zhou, Weiwei

    2015-08-14

    Heterostructures of metal nanoparticles and semiconductors are widely studied for their unique properties. However, few reports are available on the heterostructure of metal nanoclusters and semiconductors. In the present study, a heterostructure, in which gold nanoclusters selectively locate at ZnS quantum rod (QR) tips, was fabricated using a two-step solvothermal route. The composition, intrinsic crystallography, and junction of the prepared heterostructure were thoroughly investigated, and it was observed to exhibit novel luminescent behaviours. By comparison with the individual components of ZnS QRs and gold clusters, the resultant heterostructure shows an enhanced exciton emission and complete depression of defect emission for the ZnS component, and a pronounced red emission for the gold nanocluster component. The mechanism of these properties and the charge transfer between gold nanoclusters and ZnS QRs were also explored. The size and location of gold in the heterostructure were also controlled during synthesis to study their effects on the luminescence.

  4. Method of fabricating composite superconductors

    International Nuclear Information System (INIS)

    Koike, Y.; Shiraki, H.; Suzuki, E.; Yoshida, M.

    1977-01-01

    A method of making stabilized superconductors of a composition such as Nb 3 Sn is disclosed. The method includes forming a stock product comprising a tin base alloy as a core with a copper jacket and having a niobium tube clad thereon. The stock product is then embedded in a good thermally and electrically conducting matrix which is then coreduced until the desired size is obtained. This cold worked product is then submitted to a heat treatment to form superconductors of Nb 3 Sn

  5. A scalable synthesis of highly stable and water dispersible Ag 44(SR)30 nanoclusters

    KAUST Repository

    AbdulHalim, Lina G.

    2013-01-01

    We report the synthesis of atomically monodisperse thiol-protected silver nanoclusters [Ag44(SR)30] m, (SR = 5-mercapto-2-nitrobenzoic acid) in which the product nanocluster is highly stable in contrast to previous preparation methods. The method is one-pot, scalable, and produces nanoclusters that are stable in aqueous solution for at least 9 months at room temperature under ambient conditions, with very little degradation to their unique UV-Vis optical absorption spectrum. The composition, size, and monodispersity were determined by electrospray ionization mass spectrometry and analytical ultracentrifugation. The produced nanoclusters are likely to be in a superatom charge-state of m = 4-, due to the fact that their optical absorption spectrum shares most of the unique features of the intense and broadly absorbing nanoparticles identified as [Ag44(SR) 30]4- by Harkness et al. (Nanoscale, 2012, 4, 4269). A protocol to transfer the nanoclusters to organic solvents is also described. Using the disperse nanoclusters in organic media, we fabricated solid-state films of [Ag44(SR)30]m that retained all the distinct features of the optical absorption spectrum of the nanoclusters in solution. The films were studied by X-ray diffraction and photoelectron spectroscopy in order to investigate their crystallinity, atomic composition and valence band structure. The stability, scalability, and the film fabrication method demonstrated in this work pave the way towards the crystallization of [Ag44(SR)30]m and its full structural determination by single crystal X-ray diffraction. Moreover, due to their unique and attractive optical properties with multiple optical transitions, we anticipate these clusters to find practical applications in light-harvesting, such as photovoltaics and photocatalysis, which have been hindered so far by the instability of previous generations of the cluster. © 2013 The Royal Society of Chemistry.

  6. Impact damage in woven fabric reinforced composites

    NARCIS (Netherlands)

    Akkerman, Remko; Warnet, Laurent; van der Ven, E.C.

    2002-01-01

    Very often, woven fabrics are used as the reinforcement in advanced composite materials. Although the resulting inplane stiffness is lower than of their unidirectional counterparts, the excellent drapability of these materials eases the production of more general doubly curved components. In

  7. Natural fabric sandwich laminate composites: development and ...

    Indian Academy of Sciences (India)

    Natural fabrics; jute; linen; sandwich laminate; mechanical properties; fractographic analysis. 1. Introduction. Owing to ecological necessities and strict regulations, incor- porating natural fibres in the place of synthetic fibres becomes inevitable for the manufacturers to accomplish new composite materials originated from ...

  8. Natural fabric sandwich laminate composites: development and ...

    Indian Academy of Sciences (India)

    Sci., Vol. 40, No. 1, February 2017, pp. 139–146. c Indian Academy of Sciences. DOI 10.1007/s12034-016-1356-y. Natural fabric sandwich laminate composites: development and investigation ... studied by Gassan and Bledzki [17]. An investigation on the ... spread with the aid of a brush. Another layer of reinforce- ment in ...

  9. Formation of optical properties of intermetallic nanoclusters formed by sequential ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Zuhr, R.A. [Oak Ridge National Lab., TN (United States). Solid State Div.; Magruder, R.H. III; Anderson, T.S. [Vanderbilt Univ., Nashville, TN (United States). Dept. of Applied and Engineering Sciences

    1997-09-01

    Recent demonstrations that large third order nonlinear responses can be achieved in metal nanocluster glass composites are of significant interest because of their potential for use in all optical switching networks. These composite materials exhibit picosecond switching and relaxation times, thermal and chemical stability, high laser damage thresholds, and low two photon absorption. Ion implantation has been shown to be a useful fabrication method to form these nanoclusters in silica because of its ability to produce thin films in waveguide configurations containing a high volume fraction (> 1%) of metal colloids with well defined vertical and horizontal dimensional control. Using sequential ion implantation of more than one element the authors can modify the composition and microstructure of the composites by forming intermetallic metal colloids. In this work the authors report on the improved optical response of metallic nanocluster composites formed by sequential implantation of Cd and Ag and Sb and Ag. Characterization of the samples by transmission electron microscopy (TEM) reveals that approximately spherical metallic colloids are formed for all implanted species during the implantation process. Selected area diffraction patterns indicate that the colloids formed are intermetallic in composition. Linear optical absorption measurements made at room temperature in air from 900 to 200 nm show significant changes in both the magnitude and wavelength of the surface plasmon resonance. The formation of intermetallic nanoclusters results in changes in both the linear and nonlinear optical properties of the composite material that are not possible with single element colloids alone. The results are explained in terms of effective medium theory.

  10. Fabrication of Flexible Piezoelectric PZT/Fabric Composite

    Directory of Open Access Journals (Sweden)

    Caifeng Chen

    2013-01-01

    Full Text Available Flexible piezoelectric PZT/fabric composite material is pliable and tough in nature which is in a lack of traditional PZT patches. It has great application prospect in improving the sensitivity of sensor/actuator made by piezoelectric materials especially when they are used for curved surfaces or complicated conditions. In this paper, glass fiber cloth was adopted as carrier to grow PZT piezoelectric crystal particles by hydrothermal method, and the optimum conditions were studied. The results showed that the soft glass fiber cloth was an ideal kind of carrier. A large number of cubic-shaped PZT nanocrystallines grew firmly in the carrier with a dense and uniform distribution. The best hydrothermal condition was found to be pH 13, reaction time 24 h, and reaction temperature 200°C.

  11. Fabrication of novel compound SERS substrates composed of silver nanoparticles and porous gold nanoclusters: A study on enrichment detection of urea

    Science.gov (United States)

    Li, Yali; Li, Qianwen; Sun, Chengbin; Jin, Sila; Park, Yeonju; Zhou, Tieli; Wang, Xu; Zhao, Bing; Ruan, Weidong; Jung, Young Mee

    2018-01-01

    A new type of surface-enhanced Raman scattering (SERS) substrate was fabricated through the layer-by-layer self-assembly of silver nanoparticles (AgNPs, av. 45 nm in diameter) and porous gold nanoclusters/nanoparticles (AuNPs, av. 143 nm in diameter). The development of the porosity of the AuNPs was investigated, and successful SERS applications of the porous AuNPs were also examined. As compared with AgNP films, the enhancement factor of Ag-Au compound substrates is increased 6 times at the concentration of 10-6 M. This additional enhancement contributes to the trace-amount-detection of target molecules enormously. The contribution is generated through the increase of the usable surface area arising from the nanoscale pores distributed three-dimensionally in the porous AuNPs, which enrich the adsorption sites and hot spots for the adsorption of probe molecules, making the developed nanofilms highly sensitive SERS substrates. The substrates were used for the detection of a physiological metabolite of urea molecules. The results reached to a very low concentration of 1 mM and exhibited good quantitative character over the physiological concentration range (1 ∼ 20 mM) under mimicking biophysical conditions. These results show that the prepared substrate has great potential in the ultrasensitive SERS-based detection and in SERS-based biosensors.

  12. Method of Fabricating a Piezoelectric Composite Apparatus

    Science.gov (United States)

    Wilkie, W. Keats (Inventor); Bryant, Robert (Inventor); Fox, Robert L. (Inventor); Hellbaum, Richard F. (Inventor); High, James W. (Inventor); Jalink, Antony, Jr. (Inventor); Little, Bruce D. (Inventor); Mirick, Paul H. (Inventor)

    2003-01-01

    A method for fabricating a piezoelectric macro-fiber composite actuator comprises providing a piezoelectric material that has two sides and attaching one side upon an adhesive backing sheet. The method further comprises slicing the piezoelectric material to provide a plurality of piezoelectric fibers in juxtaposition. A conductive film is then adhesively bonded to the other side of the piezoelectric material, and the adhesive backing sheet is removed. The conductive film has first and second conductive patterns formed thereon which are electrically isolated from one another and in electrical contact with the piezoelectric material. The first and second conductive patterns of the conductive film each have a plurality of electrodes to form a pattern of interdigitated electrodes. A second film is then bonded to the other side of the piezoelectric material. The second film may have a pair of conductive patterns similar to the conductive patterns of the first film.

  13. Method of Fabricating a Composite Apparatus

    Science.gov (United States)

    Wilkie, W. Keats (Inventor); Bryant, Robert G. (Inventor); Fox, Robert L. (Inventor); Hellbaum, Richard F. (Inventor); High, James W. (Inventor); Jalink, Antony, Jr. (Inventor)

    2007-01-01

    A method for fabricating a piezoelectric macro-fiber composite actuator comprises making a piezoelectric fiber sheet by providing a plurality of wafers of piezoelectric material, bonding the wafers together with an adhesive material to from a stack of alternating layers of piezoelectric material and adhesive material, and cutting through the stack in a direction substantially parallel to the thickness of the stack and across the alternating layers of piezoelectric material and adhesive material to provide at least one piezoelectric fiber sheet having two sides comprising a plurality of piezoelectric fibers in juxtaposition to the adhesive material. The method further comprises bonding two electrically conductive films to the two sides of the piezoelectric fiber sheet. At least one conductive film has first and second conductive patterns formed thereon which are electrically isolated from one another and in electrical contact with the piezoelectric fiber sheet.

  14. Optimum processing parameters for the fabrication of twill flax fabric-reinforced polypropylene (PP) composites

    Science.gov (United States)

    Zuhudi, Nurul Zuhairah Mahmud; Minhat, Mulia; Shamsuddin, Mohd Hafizi; Isa, Mohd Dali; Nur, Nurhayati Mohd

    2017-12-01

    In recent years, natural fabric thermoplastic composites such as flax have received much attention due to its attractive capabilities for structural applications. It is crucial to study the processing of flax fabric materials in order to achieve good quality and cost-effectiveness in fibre reinforced composites. Though flax fabric has been widely utilized for several years in composite applications due to its high strength and abundance in nature, much work has been concentrated on short flax fibre and very little work focused on using flax fabric. The effectiveness of the flax fabric is expected to give higher strength performance due to its structure but the processing needs to be optimised. Flax fabric composites were fabricated using compression moulding due to its simplicity, gives good surface finish and relatively low cost in terms of labour and production. Further, the impregnation of the polymer into the fabric is easier in this process. As the fabric weave structure contributes to the impregnation quality which leads to the overall performance, the processing parameters of consolidation i.e. pressure, time, and weight fraction of fabric were optimized using the Taguchi method. This optimization enhances the consolidation quality of the composite by improving the composite mechanical properties, three main tests were conducted i.e. tensile, flexural and impact test. It is observed that the processing parameter significantly affected the consolidation and quality of composite.

  15. Bone formation: The rules for fabricating a composite ceramic

    Energy Technology Data Exchange (ETDEWEB)

    Caplan, A.I. (Case Western Reserve Univ., Cleveland, OH (USA))

    1990-01-01

    Bone, teeth and shells are complex composite ceramics which are fabricated at low temperature by living organisms. The detailed understanding of this fabrication process is required if we are to attempt to mimic this low temperature assembly process. The guiding principles and major components are outlined with the intent of establishing non-vital fabrication schemes to form a complex composite ceramic consisting of an organix matrix inorganic crystalline phase. 19 refs.

  16. Radiation-sustained nanocluster metastability in oxide dispersion strengthened materials

    Energy Technology Data Exchange (ETDEWEB)

    Ribis, J., E-mail: joel.ribis@cea.fr [CEA, DEN, SRMA, F-91191 Gif sur Yvette (France); Bordas, E.; Trocellier, P.; Serruys, Y. [CEA, DEN, Service de Recherches de Métallurgie Physique, Laboratoire JANNUS, 91191 Gif sur Yvette (France); Carlan, Y. de [CEA, DEN, SRMA, F-91191 Gif sur Yvette (France); Legris, A. [UMET, CNRS/UMR 8207, Bât. C6, Univ. Lille 1, 59655 Villeneuve d’Ascq (France)

    2015-12-15

    ODS materials constitute a new promising class of structural materials for advanced fission and fusion energy application. These Fe–Cr based ferritic steels contain ultra-high density of dispersion-strengthening nanoclusters conferring excellent mechanical properties to the alloy. Hence, guarantee the nanocluster stability under irradiation remain a critical issue. Nanoclusters are non-equilibrium multicomponent compounds (YTiCrO) forming through a complex nucleation pathway during the elaboration process. In this paper, it is proposed to observe the response of these nanoclusters when the system is placed far from equilibrium by means of ion beam. The results indicate that the Y, Ti, O and Cr atoms self-organized so that nanoclusters coarsened but maintain their non-equilibrium chemical composition. It is discussed that the radiation-sustained nanocluster metastability emerges from cooperative effects: radiation-induced Ostwald ripening, permanent creation of vacancies in the clusters, and fast Cr diffusion mediated by interstitials.

  17. Fique Fabric: A Promising Reinforcement for Polymer Composites

    Directory of Open Access Journals (Sweden)

    Sergio Neves Monteiro

    2018-02-01

    Full Text Available A relatively unknown natural fiber extracted from the leaves of the fique plant, native of the South American Andes, has recently shown potential as reinforcement of polymer composites for engineering applications. Preliminary investigations indicated a promising substitute for synthetic fibers, competing with other well-known natural fibers. The fabric made from fique fibers have not yet been investigated as possible composite reinforcement. Therefore, in the present work a more thorough characterization of fique fabric as a reinforcement of composites with a polyester matrix was performed. Thermal mechanical properties of fique fabric composites were determined by dynamic mechanical analysis (DMA. The ballistic performance of plain woven fique fabric-reinforced polyester matrix composites was investigated as a second layer in a multilayered armor system (MAS. The results revealed a sensible improvement in thermal dynamic mechanical behavior. Both viscoelastic stiffness and glass transition temperature were increased with the amount of incorporated fique fabric. In terms of ballistic results, the fique fabric composites present a performance similar to that of the much stronger KevlarTM as an MAS second layer with the same thickness. A cost analysis indicated that armor vests with fique fabric composites as an MAS second layer would be 13 times less expensive than a similar creation made with Kevlar™.

  18. Composite metal foil and ceramic fabric materials

    Science.gov (United States)

    Webb, Brent J.; Antoniak, Zen I.; Prater, John T.; DeSteese, John G.

    1992-01-01

    The invention comprises new materials useful in a wide variety of terrestrial and space applications. In one aspect, the invention comprises a flexible cloth-like material comprising a layer of flexible woven ceramic fabric bonded with a layer of metallic foil. In another aspect, the invention includes a flexible fluid impermeable barrier comprising a flexible woven ceramic fabric layer having metal wire woven therein. A metallic foil layer is incontinuously welded to the woven metal wire. In yet another aspect, the invention includes a material comprising a layer of flexible woven ceramic fabric bonded with a layer of an organic polymer. In still another aspect, the invention includes a rigid fabric structure comprising a flexible woven ceramic fabric and a resinous support material which has been hardened as the direct result of exposure to ultraviolet light. Inventive methods for producing such material are also disclosed.

  19. The Design, Fabrication, and Testing of Composite Heat Exchange Coupons

    Science.gov (United States)

    Quade, Derek J.; Meador, Michael A.; Shin, Euy-Sik; Johnston, James C.; Kuczmarski, Maria A.

    2011-01-01

    Several heat exchanger (HX) test panels were designed, fabricated and tested at the NASA Glenn Research Center to explore the fabrication and performance of several designs for composite heat exchangers. The development of these light weight, high efficiency air-liquid test panels was attempted using polymer composites and carbon foam materials. The fundamental goal of this effort was to demonstrate the feasibility of the composite HX for various space exploration and thermal management applications including Orion CEV and Altair. The specific objectives of this work were to select optimum materials, designs, and to optimize fabrication procedures. After fabrication, the individual design concept prototypes were tested to determine their thermal performance and to guide the future development of full-size engineering development units (EDU). The overall test results suggested that the panel bonded with pre-cured composite laminates to KFOAM Grade L1 scored above the other designs in terms of ease of manufacture and performance.

  20. Design and Fabrication of Aerospace-Grade Digital Composite Materials

    Data.gov (United States)

    National Aeronautics and Space Administration — This project aims to advance design rules and fabrication approaches to create aerospace-grade structures from digital composite materials. Digital materials are...

  1. Ratiometric Fluorescent Detection of Phosphate in Aqueous Solution Based on Near Infrared Fluorescent Silver Nanoclusters/Metal-Organic Shell Composite.

    Science.gov (United States)

    Dai, Cong; Yang, Cheng-Xiong; Yan, Xiu-Ping

    2015-11-17

    Synthesis of near-infrared (NIR) fluorescent AgNCs with high quantum yield and stability is challenging but important for sensing and bioimaging application. Here, we report the fabrication of AgNCs/metal-organic shell composite via the deposition of metal-organic (zinc-nitrogen) coordination shell around AgNCs for ratiometric detection of phosphate. The composite exhibits NIR emission at 720 nm with 30 nm red-shift in comparison to bare AgNCs and a weak emission at 510 nm from the shell. The absolute quantum yield of NIR fluorescence of the composite is 15%, owing to FRET from the shell to the AgNCs core under the excitation at 430 nm. Besides, the composite is stable due to the protection of the shell. On the basis of the composite, a novel ratiometric fluorescence probe for the detection of phosphate in aqueous solution with good sensitivity and selectivity was developed. The limit of detection (3s) is 0.06 μM, and the relative standard deviation for 10 replicate detections of 10 μM phosphate was 0.6%. The recoveries of spiked phosphate in water, human urine, and serum samples ranged from 94.1% to 103.4%.

  2. Investigation on mechanical properties of basalt composite fabrics (experiment study

    Directory of Open Access Journals (Sweden)

    Talebi Mazraehshahi H.

    2010-06-01

    Full Text Available To fully appreciate the role and application of composite materials to structures, correct understanding of mechanical behaviors required for selection of optimum material. Fabric reinforced composites are composed of a matrix that is reinforced with pliable fabric, glass fabric is most popular reinforcement for different application specially in aircraft structure, although other fabric material are also used. At this study new fabric material called basalt with epoxy resin introduced and mechanical behaviors of this material investigated from view point of testing. For this study two type of fabric with different thickness used. Comparison between this composite reinforcement with popular reinforcement as carbon, glass, kevlar performed. To determine mechanical properties of epoxy based basalt fabric following test procedure performed : 1. Tensile testing according to ASTM D3039 in 0° and 90° direction to find ultimate strength in tension and shear, modulus of elasticity, elangation and ultimate strain. 2. Compression testing according to EN 2850 ultimate compression strength and maximum deformation under compression loading. 3. Shear testing according to ASTM D3518-94 to find in plane shear response of polymer matrix composites materials. 4. Predict flexural properties of sandwich construction which manufactured from basalt facing with PVC foam core according to ASTM C393-94. Material strength properties must be based on enough tests of material to meet the test procedure specifications [1]. For this reason six specimens were manufactured for testing and the tests were performed on them using an INSTRON machine model 5582. In the study, the effect of percent of resin in basalt reinforced composite was investigated. Also the weights of the ballast based composites with different percent of resin were measured with conventional composites. As the weight is an important parameter in aerospace industry when the designer wants to replace one

  3. Investigation on mechanical properties of basalt composite fabrics (experiment study)

    Science.gov (United States)

    Talebi Mazraehshahi, H.; Zamani, H.

    2010-06-01

    To fully appreciate the role and application of composite materials to structures, correct understanding of mechanical behaviors required for selection of optimum material. Fabric reinforced composites are composed of a matrix that is reinforced with pliable fabric, glass fabric is most popular reinforcement for different application specially in aircraft structure, although other fabric material are also used. At this study new fabric material called basalt with epoxy resin introduced and mechanical behaviors of this material investigated from view point of testing. For this study two type of fabric with different thickness used. Comparison between this composite reinforcement with popular reinforcement as carbon, glass, kevlar performed. To determine mechanical properties of epoxy based basalt fabric following test procedure performed : 1). Tensile testing according to ASTM D3039 in 0° and 90° direction to find ultimate strength in tension and shear, modulus of elasticity, elangation and ultimate strain. 2). Compression testing according to EN 2850 ultimate compression strength and maximum deformation under compression loading. 3). Shear testing according to ASTM D3518-94 to find in plane shear response of polymer matrix composites materials. 4). Predict flexural properties of sandwich construction which manufactured from basalt facing with PVC foam core according to ASTM C393-94. Material strength properties must be based on enough tests of material to meet the test procedure specifications [1]. For this reason six specimens were manufactured for testing and the tests were performed on them using an INSTRON machine model 5582. In the study, the effect of percent of resin in basalt reinforced composite was investigated. Also the weights of the ballast based composites with different percent of resin were measured with conventional composites. As the weight is an important parameter in aerospace industry when the designer wants to replace one material with

  4. Design, Static Analysis And Fabrication Of Composite Joints

    Science.gov (United States)

    Mathiselvan, G.; Gobinath, R.; Yuvaraja, S.; Raja, T.

    2017-05-01

    The Bonded joints will be having one of the important issues in the composite technology is the repairing of aging in aircraft applications. In these applications and also for joining various composite material parts together, the composite materials fastened together either using adhesives or mechanical fasteners. In this paper, we have carried out design, static analysis of 3-D models and fabrication of the composite joints (bonded, riveted and hybrid). The 3-D model of the composite structure will be fabricated by using the materials such as epoxy resin, glass fibre material and aluminium rivet for preparing the joints. The static analysis was carried out with different joint by using ANSYS software. After fabrication, parametric study was also conducted to compare the performance of the hybrid joint with varying adherent width, adhesive thickness and overlap length. Different joint and its materials tensile test result have compared.

  5. Role of carbon fabric in carbon-carbon composite reinforcement

    Czech Academy of Sciences Publication Activity Database

    Košková, B.; Glogar, Petr

    7(113) (1999), s. 63-79 ISSN 1212-1576 R&D Projects: GA ČR GA106/96/0596 Institutional research plan: CEZ:AV0Z3046908 Keywords : carbon-carbon composite * fabric reinforcement * braided reinforcement Subject RIV: JI - Composite Materials

  6. Natural fabric of Hildegardia populifolia composites

    CSIR Research Space (South Africa)

    Guduri, BBR

    2006-12-01

    Full Text Available -polycarbonate toughened epoxy composites was investigated using Instron and scanning electron microscope (SEM). It was found that the presence of NaOH and silane coupling agent treatment has an effect on the mechanical properties of composites. In the presence of surface...

  7. Organic-inorganic composites for THz device fabrication

    Science.gov (United States)

    Cai, B.; Ye, T. M.; Bo, G.; Wang, X. C.; Li, Y. Z.; Zhu, Y. M.; Sugihara, O.

    2016-02-01

    In this paper, several organic-inorganic composites were prepared for Terahertz (THz) devices fabrication. First, a two-layer structure was designed for femtosecond (fs) laser/THz radiation separation. The top layer was made by sintered 20-40 nm hollow quartz particles which can diffuse the incident fs laser thus decrease the power intensity. The bottom layer comprised of silicon 100 nm particles and cycle-olefine polymer (COP), by which the fs laser light can be greatly scattered and absorbed but THz radiation can propagate insusceptibly. With this two-layer structure a high efficient fs-laser/THz filter was fabricated successfully. Second, titania-polymer composites with a very high refractiveindex tunability and high transparency in the THz region were prepared. By controlling the blending ratio of the titania particle, a broad refractive-index tuning range from 1.5 to 3.1 was realized. Then, the composites were used to fabricate antireflective (AR) layers on a high-resistivity silicon (HR-Si) substrate. By utilizing the thermoplasticity of the titania- polymer composite, a graded-index structure was fabricated via a hot-embossing method. Because of the good refractive-index matching between the composite and the HR-Si substrate, a broadband AR layer was fabricated.

  8. A Wear Geometry Model of Plain Woven Fabric Composites

    Directory of Open Access Journals (Sweden)

    Gu Dapeng

    2014-09-01

    Full Text Available The paper g describes a model meant for analysis of the wear geometry of plain woven fabric composites. The referred model consists of a mathematical description of plain woven fabric based on Peirce’s model coupled with a stratified method for the solution of the wear geometry. The evolutions of the wear area ratio of weft yarn, warp yarn and matrix resin on the worn surface are simulated by MatLab software in combination of warp and weft yarn diameters, warp and weft yarn-to-yarn distances, fabric structure phases (SPs. By comparing theoretical and experimental results from the PTFE/Kevlar fabric wear experiment, it can be concluded that the model can present a trend of the component area ratio variations along with the thickness of fabric, but has a inherently large error in quantitative analysis as an idealized model.

  9. Finite element analysis of the stiffness of fabric reinforced composites

    Science.gov (United States)

    Foye, R. L.

    1992-01-01

    The objective of this work is the prediction of all three dimensional elastic moduli of textile fabric reinforced composites. The analysis is general enough for use with complex reinforcing geometries and capable of subsequent improvements. It places no restrictions on fabric microgeometry except that the unit cell be determinate and rectangular. The unit cell is divided into rectangular subcells in which the reinforcing geometries are easier to define and analyze. The analysis, based on inhomogeneous finite elements, is applied to a variety of weave, braid, and knit reinforced composites. Some of these predictions are correlated to test data.

  10. Nanoparticles with tunable shape and composition fabricated by nanoimprint lithography

    International Nuclear Information System (INIS)

    Alayo, Nerea; Bausells, Joan; Pérez-Murano, Francesc; Conde-Rubio, Ana; Labarta, Amilcar; Batlle, Xavier; Borrisé, Xavier

    2015-01-01

    Cone-like and empty cup-shaped nanoparticles of noble metals have been demonstrated to provide extraordinary optical properties for use as optical nanoanntenas or nanoresonators. However, their large-scale production is difficult via standard nanofabrication methods. We present a fabrication approach to achieve arrays of nanoparticles with tunable shape and composition by a combination of nanoimprint lithography, hard-mask definition and various forms of metal deposition. In particular, we have obtained arrays of empty cup-shaped Au nanoparticles showing an optical response with distinguishable features associated with the excitations of localized surface plasmons. Finally, this route avoids the most common drawbacks found in the fabrication of nanoparticles by conventional top-down methods, such as aspect ratio limitation, blurring, and low throughput, and it can be used to fabricate nanoparticles with heterogeneous composition. (paper)

  11. Fabrication of Composite Combustion Chamber/Nozzle for Fastrac Engine

    Science.gov (United States)

    Lawrence, T.; Beshears, R.; Burlingame, S.; Peters, W.; Prince, M.; Suits, M.; Tillery, S.; Burns, L.; Kovach, M.; Roberts, K.

    2001-01-01

    The Fastrac Engine developed by the Marshall Space Flight Center for the X-34 vehicle began as a low cost engine development program for a small booster system. One of the key components to reducing the engine cost was the development of an inexpensive combustion chamber/nozzle. Fabrication of a regeneratively cooled thrust chamber and nozzle was considered too expensive and time consuming. In looking for an alternate design concept, the Space Shuttle's Reusable Solid Rocket Motor Project provided an extensive background with ablative composite materials in a combustion environment. An integral combustion chamber/nozzle was designed and fabricated with a silica/phenolic ablative liner and a carbon/epoxy structural overwrap. This paper describes the fabrication process and developmental hurdles overcome for the Fastrac engine one-piece composite combustion chamber/nozzle.

  12. Fabrication of low specific resistance ceramic carbon composites by ...

    Indian Academy of Sciences (India)

    2017-09-07

    Sep 7, 2017 ... C showing resistor behaviour even at low carbon content (1 wt%). In this work, ceramic carbon composites were fabricated using alumina–clay slurries with addition of glucose as a soluble carbon source. Morphology of the sintered samples was characterized by field emission gun (FEG) electron ...

  13. Processes for fabricating composite reinforced material

    Science.gov (United States)

    Seals, Roland D.; Ripley, Edward B.; Ludtka, Gerard M.

    2015-11-24

    A family of materials wherein nanostructures and/or nanotubes are incorporated into a multi-component material arrangement, such as a metallic or ceramic alloy or composite/aggregate, producing a new material or metallic/ceramic alloy. The new material has significantly increased strength, up to several thousands of times normal and perhaps substantially more, as well as significantly decreased weight. The new materials may be manufactured into a component where the nanostructure or nanostructure reinforcement is incorporated into the bulk and/or matrix material, or as a coating where the nanostructure or nanostructure reinforcement is incorporated into the coating or surface of a "normal" substrate material. The nanostructures are incorporated into the material structure either randomly or aligned, within grains, or along or across grain boundaries.

  14. Nano-fabricated superconducting radio-frequency composites, method for producing nano-fabricated superconducting rf composites

    Science.gov (United States)

    Norem, James H.; Pellin, Michael J.

    2013-06-11

    Superconducting rf is limited by a wide range of failure mechanisms inherent in the typical manufacture methods. This invention provides a method for fabricating superconducting rf structures comprising coating the structures with single atomic-layer thick films of alternating chemical composition. Also provided is a cavity defining the invented laminate structure.

  15. Industry to Education Technical Transfer Program & Composite Materials. Composite Materials Course. Fabrication I Course. Fabrication II Course. Composite Materials Testing Course. Final Report.

    Science.gov (United States)

    Massuda, Rachel

    These four reports provide details of projects to design and implement courses to be offered as requirements for the associate degree program in composites and reinforced plastics technology. The reports describe project activities that led to development of curricula for four courses: composite materials, composite materials fabrication I,…

  16. Fabrication and testing of SMA composite beam with shape control

    Science.gov (United States)

    Noolvi, Basavaraj; S, Raja; Nagaraj, Shanmukha; Mudradi, Varada Raj

    2017-07-01

    Smart materials are the advanced materials that have characteristics of sensing and actuation in response to the external stimuli like pressure, heat or electric charge etc. These materials can be integrated in to any structure to make it smart. From the different types of smart materials available, Shape Memory Alloy (SMA) is found to be more useful in designing new applications, which can offer more actuating speed, reduce the overall weight of the structure. The unique property of SMA is the ability to remember and recover from large strains of upto 8% without permanent deformation. Embedding the SMA wire/sheet in fiber-epoxy/flexible resin systems has many potential applications in Aerospace, Automobile, Medical, Robotics and various other fields. In this work the design, fabrication, and testing of smart SMA composite beam has been carried out. Two types of epoxy based resin systems namely LY 5210 resin system and EPOLAM 2063 resin system are used in fabricating the SMA composite specimens. An appropriate mould is designed and fabricated to retain the pre-strain of SMA wire during high temperature post curing of composite specimens. The specimens are fabricated using vacuum bag technique.

  17. Composite smart materials using high-volume microelectronics fabrication techniques

    Science.gov (United States)

    Winzer, Stephen R.; Shankar, Natarajan; Caldwell, Paul J.; May, Russell G.

    1995-05-01

    Smart materials, containing sensors, actuators and processing electronics, are of great potential use in defense and commercial applications from acoustic stealth to medial imaging. While 1:3 composites using PZT rods are now available commercially in limited quantities, composites with individually addressable actuator and sensor arrays are not, nor have conditioning and processing electronics been embedded in the same material. There are several technical and cost reasons for this, including the complexity of interconnections, capacitance of individual elements, thermal dissipation, and the expense of fabricating the material. We have been developing composite materials comprising arrays of miniature actuators fabricated using surface mount capacitor technology, and amenable to automated fabrication using `pick and place' techniques. Miniature actuators with up to 0.1% strain, and operating at 30 V bias and ac swing of +/- 30 V have been fabricated, and placed in 10-by- 10 actuator arrays on Kapton sheets on which circuits have been printed. The arrays were then `potted' in RTV liquid rubbers. Individual actuator motion and multiple actuator influence functions were measured as a function of applied voltage and adjacent actuator motion. These results, along with in-water performance (source level and directivity), are presented.

  18. Fabrication and Characterization of Silicon Carbide Epoxy Composites

    Science.gov (United States)

    Townsend, James

    Nanoscale fillers can significantly enhance the performance of composites by increasing the extent of filler-to-matrix interaction. Thus far, the embedding of nanomaterials into composites has been achieved, but the directional arrangement has proved to be a challenging task. Even with advances in in-situ and shear stress induced orientation, these methods are both difficult to control and unreliable. Therefore, the fabrication of nanomaterials with an ability to orient along a magnetic field is a promising pathway to create highly controllable composite systems with precisely designed characteristics. To this end, the goal of this dissertation is to develop magnetically active nanoscale whiskers and study the effect of the whiskers orientation in a polymer matrix on the nanocomposite's behavior. Namely, we report the surface modification of silicon carbide whiskers (SiCWs) with magnetic nanoparticles and fabrication of SiC/epoxy composite materials. The magnetic nanoparticles attachment to the SiCWs was accomplished using polyelectrolyte polymer-to-polymer complexation. The "grafting to" and adsorption techniques were used to attach the polyelectrolytes to the surface of the SiCWs and magnetic nanoparticles. The anchored polyelectrolytes were polyacrylic acid (PAA) and poly(2-vinylpyridine) (P2VP). Next, the SiC/epoxy composites incorporating randomly oriented and magnetically oriented whiskers were fabricated. The formation of the composite was studied to determine the influence of the whiskers' surface composition on the epoxy curing reaction. After curing, the composites' thermal and thermo-mechanical properties were studied. These properties were related to the dispersion and orientation of the fillers in the composite samples. The obtained results indicated that the thermal and thermo-mechanical properties could be improved by orienting magnetically-active SiCWs inside the matrix. Silanization, "grafting to", adsorption, and complexation were used to modify

  19. Net-Shape Tailored Fabrics For Complex Composite Structures

    Science.gov (United States)

    Farley, Gary L.

    1995-01-01

    Proposed novel looms used to make fabric preforms for complex structural elements, both stiffening elements and skin, from continuous fiber-reinforced composite material. Components of looms include custom reed and differential fabric takeup system. Structural parts made best explained by reference to curved "I" cross-section frame. Technology not limited to these fiber orientations or geometry; fiber angles, frame radius of curvature, frame height, and flange width changed along length of structure. Weaving technology equally applicable to structural skins, such as wing of fuselage skins.

  20. Surface structures and compositions of Au-Rh bimetallic nanoclusters supported on thin-film Al2O3/NiAl(100) probed with CO.

    Science.gov (United States)

    Lee, Hsuan; Liao, Zhen-He; Hsu, Po-Wei; Hung, Ting-Chieh; Wu, Yu-Cheng; Lin, Yuwei; Wang, Jeng-Han; Luo, Meng-Fan

    2017-07-28

    The surface structures and compositions of Au-Rh bimetallic nanoclusters on an ordered thin film of Al 2 O 3 /NiAl(100) were investigated, primarily with infrared reflection absorption spectra and temperature-programmed desorption of CO as a probe molecule under ultrahigh-vacuum conditions and calculations based on density-functional theory. The bimetallic clusters were formed by sequential deposition of vapors of Au and Rh onto Al 2 O 3 /NiAl(100) at 300 K. Alloying in the clusters was active and proceeded toward a specific structure-a fcc phase, (100) orientation, and Rh core-Au shell structure, regardless of the order of metal deposition. For Au clusters incorporating deposited Rh, the Au atoms remained at the cluster surface through position exchange and became less coordinated; for deposition in reverse order, deposited Au simply decorated the surfaces of Rh clusters. Both adsorption energy and infrared absorption intensity were enhanced for CO on Au sites of the bimetallic clusters; both of them are associated with the bonding to Rh and also a decreased coordination number of CO-binding Au. These enhancements can thus serve as a fingerprint for alloying and atomic inter-diffusion in similar bimetallic systems.

  1. Fabrication of Fe-Based Diamond Composites by Pressureless Infiltration

    Directory of Open Access Journals (Sweden)

    Meng Li

    2016-12-01

    Full Text Available A metal-based matrix is usually used for the fabrication of diamond bits in order to achieve favorable properties and easy processing. In the effort to reduce the cost and to attain the desired bit properties, researchers have brought more attention to diamond composites. In this paper, Fe-based impregnated diamond composites for drill bits were fabricated by using a pressureless infiltration sintering method at 970 °C for 5 min. In addition, boron was introduced into Fe-based diamond composites. The influence of boron on the density, hardness, bending strength, grinding ratio, and microstructure was investigated. An Fe-based diamond composite with 1 wt % B has an optimal overall performance, the grinding ratio especially improving by 80%. After comparing with tungsten carbide (WC-based diamond composites with and without 1 wt % B, results showed that the Fe-based diamond composite with 1 wt % B exhibits higher bending strength and wear resistance, being satisfactory to bit needs.

  2. Fabrication of an Electrically-Resistive, Varistor-Polymer Composite

    Directory of Open Access Journals (Sweden)

    Sanaz A. Mohammadi

    2012-11-01

    Full Text Available This study focuses on the fabrication and electrical characterization of a polymer composite based on nano-sized varistor powder. The polymer composite was fabricated by the melt-blending method. The developed nano-composite was characterized by X-ray diffraction (XRD, transmission electron microscopy (TEM, field emission scanning electron microscopy (FeSEM, and energy-dispersive X-ray spectroscopy (EDAX. The XRD pattern revealed the crystallinity of the composite. The XRD study also showed the presence of secondary phases due to the substitution of zinc by other cations, such as bismuth and manganese. The TEM picture of the sample revealed the distribution of the spherical, nano-sized, filler particles throughout the matrix, which were in the 10–50 nm range with an average of approximately 11 nm. The presence of a bismuth-rich phase and a ZnO matrix phase in the ZnO-based varistor powder was confirmed by FeSEM images and EDX spectra. From the current-voltage curves, the non-linear coefficient of the varistor polymer composite with 70 wt% of nano filler was 3.57, and its electrical resistivity after the onset point was 861 KΩ. The non-linear coefficient was 1.11 in the sample with 100 wt% polymer content. Thus, it was concluded that the composites established a better electrical non-linearity at higher filler amounts due to the nano-metric structure and closer particle linkages.

  3. Ceramic matrix composite article and process of fabricating a ceramic matrix composite article

    Science.gov (United States)

    Cairo, Ronald Robert; DiMascio, Paul Stephen; Parolini, Jason Robert

    2016-01-12

    A ceramic matrix composite article and a process of fabricating a ceramic matrix composite are disclosed. The ceramic matrix composite article includes a matrix distribution pattern formed by a manifold and ceramic matrix composite plies laid up on the matrix distribution pattern, includes the manifold, or a combination thereof. The manifold includes one or more matrix distribution channels operably connected to a delivery interface, the delivery interface configured for providing matrix material to one or more of the ceramic matrix composite plies. The process includes providing the manifold, forming the matrix distribution pattern by transporting the matrix material through the manifold, and contacting the ceramic matrix composite plies with the matrix material.

  4. Fabrication of polypeptide-based piezoelectric composite polymer film

    International Nuclear Information System (INIS)

    Farrar, Dawnielle; West, James E.; Busch-Vishniac, Ilene J.; Yu, Seungju M.

    2008-01-01

    A new class of molecular composite piezoelectric material was produced by simultaneous poling and curing of a homogeneous solution comprising poly(γ-benzyl α,L-glutamate) and methylmethacrylate via corona discharge methods. This film exhibited high piezoelectricity (d 33 = 23 pC N -1 ), and its mechanical characteristics (modulus = 450 MPa) were similar to those of low molecular weight poly(methylmethacrylate). As it is produced via solution-based fabrication processes, the composite film is conducive to miniaturization for small sensors with integrated electronics, and could also potentially be used in piezoelectric coating applications

  5. Analysis of woven fabrics for reinforced composite materials

    Science.gov (United States)

    Dow, Norris F.; Ramnath, V.; Rosen, B. Walter

    1987-01-01

    The use of woven fabrics as reinforcements for composites is considered. Methods of analysis of properties are reviewed and extended, with particular attention paid to three-dimensional constructions having through-the-thickness reinforcements. Methodology developed is used parametrically to evaluate the performance potential of a wide variety of reinforcement constructions including hybrids. Comparisons are made of predicted and measured properties of representative composites having biaxial and triaxial woven, and laminated tape lay-up reinforcements. Overall results are incorporated in advanced weave designs.

  6. Fluxible nanoclusters of Fe3O4 nanocrystal-embedded polyaniline by macromolecule-induced self-assembly.

    Science.gov (United States)

    Huang, Jing; Li, Qi; Li, Denian; Wang, Yue; Dong, Lijie; Xie, Haian; Wang, Jun; Xiong, Chuanxi

    2013-08-13

    We have prepared Fe3O4 nanocrystal-embedded polyaniline hybrids with well-defined cluster-like morphology through macromolecule-induced self-assembly. These magnetic and electrically conductive composite nanoclusters show flowability at room temperature in the absence of any solvent, which offers great potential in applications such as microwave absorbents and electromagnetic shielding coatings. This macromolecule-induced self-assembly strategy can be readily applied on the fabrication of other ion oxide/conjugated polymer composites to achieve robust multifunctional materials.

  7. Multi-facet implications of PEGylated lysozyme stabilized-silver nanoclusters loaded recombinant PTEN cargo in cancer theranostics.

    Science.gov (United States)

    Arora, Neha; Gavya S, Lalitha; Ghosh, Siddhartha S

    2018-05-01

    Amalgamation of delivery and tracking of therapeutically relevant moieties on a single platform is made possible by the application of metal nanoclusters, an innovative class of luminescent nanomaterials. Metal nanoclusters, possessing molecule-like attributes, display extraordinary size and shape tunable properties befitting theranostic applications. Herein, we report successful assembly of therapeutically significant phosphatase protein PTEN and fluorescent lysozyme-stabilized silver nanoclusters to accomplish delivery and tracking of the protein. Down-regulation of PTEN perturbs the cellular networking leading to copious pathological conditions. The integration of purified recombinant PTEN with silver nanoclusters was evaluated by fluorescence spectroscopy study. A key feature of this study is the use of polyethylene glycol coating that allows fabrication of the assembly into spherical nanocomposites as characterized by transmission electron microscope along with retention of both optical functionality of the cluster and biological activity of the protein. Prior to cellular application, the functional integrity of PTEN in the composite was determined in vitro, by enzymatic assay employing para-nitrophenylphosphate as substrate. Cellular internalization of the cargo was studied by confocal microscopy and flow cytometry analysis. The efficacy of the payload on modulation of cellular signaling was assessed on cell lines that expressed PTEN differentially. PTEN null U-87 MG and PTEN expressing MCF7 cell lines displayed successful alteration of AKT and FAK signaling proteins culminating in cell cycle arrest and reduced wound healing capacity. A dose dependent reduction in cell proliferation of MCF7 cells was achieved. For U-87 MG, treatment with the payload resulted in chemosensitization toward anti-cancer drug erlotinib. Thus, PEG coated GST-PTEN loaded silver nanoclusters serves as a comprehensive system encompassing cellular imaging and protein delivery with

  8. Early Damage Detection in Composites during Fabrication and Mechanical Testing.

    Science.gov (United States)

    Chandarana, Neha; Sanchez, Daniel Martinez; Soutis, Constantinos; Gresil, Matthieu

    2017-06-22

    Fully integrated monitoring systems have shown promise in improving confidence in composite materials while reducing lifecycle costs. A distributed optical fibre sensor is embedded in a fibre reinforced composite laminate, to give three sensing regions at different levels through-the-thickness of the plate. This study follows the resin infusion process during fabrication of the composite, monitoring the development of strain in-situ and in real time, and to gain better understanding of the resin rheology during curing. Piezoelectric wafer active sensors and electrical strain gauges are bonded to the plate after fabrication. This is followed by progressive loading/unloading cycles of mechanical four point bending. The strain values obtained from the optical fibre are in good agreement with strain data collected by surface mounted strain gauges, while the sensing regions clearly indicate the development of compressive, neutral, and tensile strain. Acoustic emission event detection suggests the formation of matrix (resin) cracks, with measured damage event amplitudes in agreement with values reported in published literature on the subject. The Felicity ratio for each subsequent loading cycle is calculated to track the progression of damage in the material. The methodology developed here can be used to follow the full life cycle of a composite structure, from manufacture to end-of-life.

  9. Fabrication Process and Reliability Evaluation of Shape Memory Alloy Composite

    International Nuclear Information System (INIS)

    Lee, Jin Kyung; Choi, Il Kook; Park, Young Chul; Lee, Kyu Chang; Lee, Joon Hyun

    2001-01-01

    Shape memory alloy has been used to improve the tensile strength of composite by the occurrence of compressive residual stress in matrix using its shape memory effect. In order to fabricate shape memory alloy composite, TiNi alloy and A16061 were used as reinforcing material and mix, respectively. In this study, TiNi/A16061 shape memory alloy composite was made by using hot press method. However, the specimen fabricated by this method had the bonding problem at the boundary between TiNi fiber and Al matrix when the load was applied to it. A cold rolling was imposed to the specimen to improve the bonding effect. It was found that tensile strength of specimen subjected to cold rolling was more increased than that of specimen which did not underwent cold rolling. In addition, acoustic emission technique was used to quantify the microscopic damage behavior of cold rolled TiNi/A16061 shape memory alloy composite at high temperature

  10. Fabrication of conductive network formed by polyaniline-ZnO composite on fabric surfaces

    International Nuclear Information System (INIS)

    Zhao Yaping; Cai Zaisheng; Zhou Zhaoyi; Fu Xiaolan

    2011-01-01

    A conductive network consisting of polyaniline (PANI) and PANI/nm-ZnO immobilized on the surfaces of poly(ethylene terephthalate) (PET) fabrics was synthesized by a route involving a wet-chemical technique and in-situ chemical oxidative polymerization procedures. Morphological, structural, thermal and electrical properties of the PET fabrics modified with PANI-ZnO composites were analyzed. X-ray diffraction (XRD) measurements of the composites revealed that the crystal structure of incorporated ZnO undergone a weak distortion during the polymerization reaction and the XRD pattern of PANI was predominate. Attenuated total reflection Fourier transform infrared spectroscopic studies indicated the presence of interaction between ZnO nanorods and molecular chains of PANI in the ZnO/PANI layers. Field emission scanning electron microscope images implied the thin composite layers showed a submicro-sized rod like network and the homogeneous distribution on the substrates. Thermogravimetric studies exhibited that the PET-ZnO/PANI composite had a higher thermal stability than anyone of PET and PET-PANI. The surface resistance of ZnO/PANI conductive films was found to be smaller than the PANI film, which was declined as aniline concentration in adsorption bath increased and reached a relatively low value when Zn(NO 3 ) 2 concentration was at 0.03 mol/L in the precursor solution.

  11. Fabrication and characterization of magnetic nanoparticle composite membranes

    Science.gov (United States)

    Cruickshank, Akeem Armand

    To effectively and accurately deliver drugs within the human body, both new designs and components for implantable micropumps are being studied. Designs must ensure high biocompatibility, drug compatibility, accuracy and small power consumption. The focus of this thesis was to fabricate a prototype magnetic nanoparticle membrane for eventual incorporation into a biomedical pump and then determine the relationship between this membrane deflection and applied pneumatic or magnetic force. The magnetic nanoparticle polymer composite (MNPC) membranes in this study were composed of crosslinked polydimethylsiloxane (PDMS) and iron oxide nanoparticles (IONPs). An optimal iron oxide fabrication route was identified and particle size in each batch was approximately 24.6 nm. Once these nanoparticles were incorporated into a membrane (5 wt. %), the nanoparticle formed agglomerates with an average diameter of 2.26 +/-1.23 microm. Comparisons between the 0 and 5 wt. % loading of particles into the membranes indicated that the elastic modulus of the composite decreased with increasing particle concentration. The pressure- central deflection of the membranes could not be predicated by prior models and variation between magnetic and pneumatic pressure-deflection curves was quantified. Attempts to fabricate membranes with above 5 wt. % nanoparticles were not successful (no gelation). Fourier Transform Infrared (FTIR) spectroscopy results suggest that excess oleic acid on the nanoparticles prior to mixing might have prevented crosslinking.

  12. Economical Fabrication of Thick-Section Ceramic Matrix Composites

    Science.gov (United States)

    Babcock, Jason; Ramachandran, Gautham; Williams, Brian; Benander, Robert

    2010-01-01

    A method was developed for producing thick-section [>2 in. (approx.5 cm)], continuous fiber-reinforced ceramic matrix composites (CMCs). Ultramet-modified fiber interface coating and melt infiltration processing, developed previously for thin-section components, were used for the fabrication of CMCs that were an order of magnitude greater in thickness [up to 2.5 in. (approx.6.4 cm)]. Melt processing first involves infiltration of a fiber preform with the desired interface coating, and then with carbon to partially densify the preform. A molten refractory metal is then infiltrated and reacts with the excess carbon to form the carbide matrix without damaging the fiber reinforcement. Infiltration occurs from the inside out as the molten metal fills virtually all the available void space. Densification to coatings to the fiber preform was also required to accommodate the high preform thickness. The thick-section CMC processing developed in this work proved to be invaluable for component development, fabrication, and testing in two complementary efforts. In a project for the Army, involving SiC/SiC blisk development, nominally 0.8 in. thick x 8 in. diameter (approx. 2 cm thick x 20 cm diameter) components were successfully infiltrated. Blisk hubs were machined using diamond-embedded cutting tools and successfully spin-tested. Good ply uniformity and extremely low residual porosity (matrix composites fabricated via CVI or PIP. The pyrolytic carbon/zirconium nitride interface coating optimized in this work for use on carbon fibers was incorporated in the SiC/SiC composites and yielded a >41 ksi (approx. 283 MPa) flexural strength.

  13. Dry friction characterisation of carbon fibre tow and satin weave fabric for composite applications

    NARCIS (Netherlands)

    Cornelissen, Bo; Sachs, Ulrich; Rietman, Bert; Akkerman, Remko

    2014-01-01

    Composites forming processes such as resin transfer moulding (RTM) typically involve a preforming step in which dry fabric material is deformed. Frictional forces in tool–fabric and fabric–fabric contacts determine the fabric deformation behaviour to a large extent. Previous investigations of the

  14. Effect of fabric material and tightness on the mechanical properties of fabric–cement composites

    Directory of Open Access Journals (Sweden)

    Magdi El Messiry

    2014-12-01

    Full Text Available This study shows the effect of fabric tightness and fabric material on the mechanical properties of fabric–cement composites. Six fabric designs from the same fabric material were used. These fabric designs are vary in the specific tightness. Also, three fabric materials with the same fabric design were used in this work. Different sets of specimens were made, after that these specimens were tested on tensile and bending testing machines. It was found that the mechanical properties of the composite materials were influenced by the length of the warp thread float, i.e. the longer is the yarns float in the fabric, the greater is the tensile strength properties of the reinforced fabric, its construction and the material of the reinforced fabric. Therefore, it is recommended to use fabric with yarns with higher tenacity in the direction of the application of load and with either long float or minimum number of intersections.

  15. Fabrication of cationic chitin nanofiber/alginate composite materials.

    Science.gov (United States)

    Sato, Koki; Tanaka, Kohei; Takata, Yusei; Yamamoto, Kazuya; Kadokawa, Jun-Ichi

    2016-10-01

    We have already found that an amidinated chitin, which was prepared by the reaction of a partially deacetylated chitin with N,N-dimethylacetamide dimethyl acetal, was converted into an amidinium chitin bicarbonate with nanofiber morphology by CO2 gas bubbling and ultrasonic treatments in water. In this study, we performed the fabrication of composite materials of such cationic chitin nanofibers with an anionic polysaccharide, sodium alginate, by ion exchange. When the amidinium chitin bicarbonate nanofiber aqueous dispersion was added to an aqueous solution of sodium alginate, the composite material was agglomerated, which was isolated by centrifugation, filtration, and lyophilization, to form a manipulatable sheet. The morphology of the resulting sheet at nano-scale was evaluated by SEM measurement. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Composites of 3D-Printed Polymers and Textile Fabrics*

    Science.gov (United States)

    Martens, Yasmin; Ehrmann, Andrea

    2017-08-01

    3D printing belongs to the rapidly emerging technologies of our time. Due to its recent drawback - the technology is relatively slow compared with other primary shaping methods, such as injection molding -, 3D printing is often not used for creating complete large components but to add specific features to existing larger objects. One of the possibilities to create such composites with an additional value consists in combining 3D printed polymers with textile fabrics. Several attempts have been made to enhance the adhesion between both materials, a task which is still challenging for diverse material combinations. Our paper reports about new experiments combining 3D printed embossed designs, snap fasteners and zip fasteners with different textile base materials, showing the possibilities and technical limits of these novel composites.

  17. New Fabrication Technique of Conductive Polymer / Insulating Polymer Composite Films

    Science.gov (United States)

    Abe, Yayoi; Mathur, Paramatma Chandra; Bhatnagar, Pramod Kumar; Tada, Kazuya; Onoda, Mitsuyoshi

    The electrochemical polymerization of pyrrole on an ITO (indium-tin oxide) coated glass electrode with an insulating film of poly(vinyl alcohol), PVA produces a flexible composite polymer film with electrical, optical and electrochemical properties very similar to polypyrrole (PPy). The rate of electrochemical polymerization depends on the diffusion of the electrolyte across the PVA film to the ITO electrode. Especially, the solvent with hydrophilic nature easily penetrates into the PVA film. By applying this new process, we demonstrate a unique method to form electrically conductive pattern in PVA film. It will be possible to develop electrodes for electrical stimulation of the nervous system using conducting polymer, PPy. Then, by using similar technique we have fabricated poly (3,4-ethylenedioxythiophene), PEDOT/PVA composite films and investigated their electrochemical basic properties.

  18. Pt, Co–Pt and Fe–Pt alloy nanoclusters encapsulated in virus capsids

    International Nuclear Information System (INIS)

    Okuda, M; Eloi, J-C; Jones, S E Ward; Schwarzacher, W; Verwegen, M; Cornelissen, J J L M

    2016-01-01

    Nanostructured Pt-based alloys show great promise, not only for catalysis but also in medical and magnetic applications. To extend the properties of this class of materials, we have developed a means of synthesizing Pt and Pt-based alloy nanoclusters in the capsid of a virus. Pure Pt and Pt-alloy nanoclusters are formed through the chemical reduction of [PtCl 4 ] − by NaBH 4 with/without additional metal ions (Co or Fe). The opening and closing of the ion channels in the virus capsid were controlled by changing the pH and ionic strength of the solution. The size of the nanoclusters is limited to 18 nm by the internal diameter of the capsid. Their magnetic properties suggest potential applications in hyperthermia for the Co–Pt and Fe–Pt magnetic alloy nanoclusters. This study introduces a new way to fabricate size-restricted nanoclusters using virus capsid. (paper)

  19. High Temperature Resin/Carbon Nanotube Composite Fabrication

    Science.gov (United States)

    Ghose, Sayata; Watson, Kent A.; Sun, Keun J.; Criss, Jim M.; Siochi, Emilie J.; Connell, John W.

    2006-01-01

    For the purpose of incorporating multifunctionality into advanced composites, blends of phenylethynyl terminated imides-330 (PETI-330) and multi-walled carbon nanotubes (MWCNTs) were prepared, characterized and fabricated into moldings. PETI-330/MWCNT mixtures were prepared at concentrations ranging from 3 to 25 weight percent by dry mixing the components in a ball mill. The resulting powders were characterized for degree of mixing, thermal and rheological properties. Based on the characterization results, PETI-330/MWCNT samples were scaled up to approximately 300 g and used to fabricate moldings by injecting the mixtures at 260-280 deg C into a stainless steel tool followed by curing for 1 h at 371 deg C. The tool was designed to impart a degree of shear during the injection process in an attempt to achieve some alignment of the MWCNTs in the flow direction. Obtained moldings were subsequently characterized for thermal, mechanical, and electrical properties. The degree of dispersion and alignment of MWCNTs were investigated using high-resolution scanning electron microscopy. The preparation and preliminary characterization of PETI-330/MWCNT composites will be discussed.

  20. Polycaprolactone/starch composite: Fabrication, structure, properties, and applications.

    Science.gov (United States)

    Ali Akbari Ghavimi, Soheila; Ebrahimzadeh, Mohammad H; Solati-Hashjin, Mehran; Abu Osman, Noor Azuan

    2015-07-01

    Interests in the use of biodegradable polymers as biomaterials have grown. Among the different polymeric composites currently available, the blend of starch and polycaprolactone (PCL) has received the most attention since the 1980s. Novamont is the first company that manufactured a PCL/starch (SPCL) composite under the trademark Mater-Bi®. The properties of PCL (a synthetic, hydrophobic, flexible, expensive polymer with a low degradation rate) and starch (a natural, hydrophilic, stiff, abundant polymer with a high degradation rate) blends are interesting because of the composite components have completely different structures and characteristics. PCL can adjust humidity sensitivity of starch as a biomaterial; while starch can enhance the low biodegradation rate of PCL. Thus, by appropriate blending, SPCL can overcome important limitations of both PCL and starch components and promote controllable behavior in terms of mechanical properties and degradation which make it suitable for many biomedical applications. This article reviewed the different fabrication and modification methods of the SPCL composite; different properties such as structural, physical, and chemical as well as degradation behavior; and different applications as biomaterials. © 2014 Wiley Periodicals, Inc.

  1. Surface-enrichment with hydroxyapatite nanoparticles in stereolithography-fabricated composite polymer scaffolds promotes bone repair

    NARCIS (Netherlands)

    Guillaume, O.; Geven, M. A.; Sprecher, C. M.; Stadelmann, V. A.; Grijpma, D. W.; Tang, T.T.; Qin, L.; Lai, Y.; Alini, M.; de Bruijn, J. D.; Yuan, H.; Richards, R.G.; Eglin, D.

    2017-01-01

    Fabrication of composite scaffolds using stereolithography (SLA) for bone tissue engineering has shown great promises. However, in order to trigger effective bone formation and implant integration, exogenous growth factors are commonly combined to scaffold materials. In this study, we fabricated

  2. GE NANOCLUSTERS IN PLANAR GLASS WAVEGUIDES DEPOSITED BY PECVD

    DEFF Research Database (Denmark)

    Haiyan, Ou; Olsen, Johnny H.; Rottwitt, Karsten

    2004-01-01

    . In this work we study the size and distribution of the nanoclusters by transmission electron microscopy (TEM) and Raman spectroscopy. The formation of the clusters is investigated by varying the Ge concentration in the glass and changing the annealing conditions such as temperature, atmosphere and time....... The combined effect of a strong nonlinear glass material and a material platform that is well known from standard planar lightwave components makes this Ge nanoclusters material very promising for optical nonlinear waveguide components that are readily fabricated by using the same processing as standard...

  3. Electromagnetic absorption behaviour of ferrite loaded three phase carbon fabric composites

    Science.gov (United States)

    Jagatheesan, Krishnasamy; Ramasamy, Alagirusamy; Das, Apurba; Basu, Ananjan

    2018-02-01

    This article investigates the electromagnetic absorption behaviours of carbon helical yarn fabric reinforced composites and manganese-zinc (Mn-Zn) ferrite particles loaded 3 phase fabric composites. A carbon helical yarn having stainless steel core was prepared and made into single jersey knitted fabric. The composite was prepared by sandwiching a fabric with polypropylene films and thermal pressed. The absorption values of helical yarn fabric composite was observed to be less in the C band region (4-8 GHz). For improving the absorption coefficients of composite, Mn-Zn ferrite particles were dispersed in the polypropylene (PP) composite. The ferrite loaded PP composites exhibited better permittivity and permeability values, hence the absorption loss of the composite was improved. The helical yarn fabric reinforced with Mn-Zn ferrite/PP composite showed larger absorption coefficients than virgin PP/fabric composite. The change in thermal stability and particle size distribution in the Mn-Zn ferrite/PP composite was also analyzed. At higher ferrite concentration, bimodal particle distribution was observed which increased the conductivity and shielding effectiveness (SE) of the composite. In addition, complex permittivity value was also increased for higher incident frequency (4-8 GHz). As the ferrite content increases, the dielectric loss and magnetic permeability of PP/ferrite increases due to increased magnetic loss. Hence, ferrite loaded PP composite showed the total SE of -14.2 dB with the absorption coefficients of 0.717. The S1C7 fabric composite having ferrite dispersion showed the better absorption loss and lower reflection coefficient of 14.2 dB and 0.345 respectively compared to virgin PP/helical yarn fabric composite. The increasing ferrite content (45 wt%) improved the absorption loss and total SE. Though, ferrite based fabric composite exhibits moderate absorptive shielding, it can be used as shielding panels in the electronic industries.

  4. Fabrication and modelling of 3-3 piezoelectric composites

    International Nuclear Information System (INIS)

    Perry, Andrew John

    2002-01-01

    Three-dimensional modelling of a 3-3 piezoelectric structure was carried out using ANSYS finite element modelling software. Hydrophone figures of merit were calculated for structures with increasing amounts of interconnecting porosity. In addition to air being the second phase, polymer fillers were added to the three dimensional model in order to observe the effect of polymer Young's modulus and Poisson's ratio on the piezoelectric response of the composite material. Results show that increasing the porosity has the effect of improving the hydrostatic piezoelectric properties for applications such as low frequency hydrophones. The optimum amount of porosity depends on the figure of merit to be maximised. In order to validate model predictions, porous piezoelectric structures were fabricated by either the BurPS (Burnt out Polymer Spheres) method or polymer foam reticulation. Corresponding measurements of piezoelectric coefficients were carried out on the porous samples. Experimental results confirmed finite element modelling predictions. PZT-porosity composites and PZT-polymer composites were produced exhibiting superior hydrostatic strain constant (d h ), hydrostatic voltage constant (g h ) and hydrostatic figure of merit (d h g h compared to that of dense PZT. (author)

  5. Improved inhomogeneous finite elements for fabric reinforced composite mechanics analysis

    Science.gov (United States)

    Foye, R. L.

    1992-01-01

    There is a need to do routine stress/failure analysis of fabric reinforced composite microstructures to provide additional confidence in critical applications and guide materials development. Conventional methods of 3-D stress analysis are time consuming to set up, run and interpret. A need exists for simpler methods of modeling these structures and analyzing the models. The principal difficulty is the discrete element mesh generation problem. Inhomogeneous finite elements are worth investigating for application to these problems because they eliminate the mesh generation problem. However, there are penalties associated with these elements. Their convergence rates can be slow compared to homogeneous elements. Also, there is no accepted method for obtaining detailed stresses in the constituent materials of each element. This paper shows that the convergence rate can be significantly improved by a simple device which substitutes homogeneous elements for the inhomogeneous ones. The device is shown to work well in simple one and two dimensional problems. However, demonstration of the application to more complex two and three dimensional problems remains to be done. Work is also progressing toward more realistic fabric microstructural geometries.

  6. Scalable fabrication of immunosensors based on carbon nanotube polymer composites

    Energy Technology Data Exchange (ETDEWEB)

    Mendoza, Ernest; Gonzalez-Guerrero, Ana B [Institut Catala de Nanotecnologia, Campus Universitat Autonoma de Barcelona, 08193 Bellaterra (Spain); Orozco, Jahir; Jimenez-Jorquera, Cecilia; Fernandez-Sanchez, Cesar [Instituto de Microelectronica de Barcelona, CNM-IMB (CSIC), Campus Universitat Autonoma de Barcelona, 08193 Bellaterra (Spain); Calle, Ana; Lechuga, Laura M [Instituto de Microelectronica de Madrid, CNM-IMM (CSIC), Isaac Newton 8, 28760 Tres Cantos, Madrid (Spain)], E-mail: Ernest.Mendoza.icn@uab.es

    2008-02-20

    In this work we present the fabrication and characterization of immunosensors based on polystyrene (PS)-multiwalled carbon nanotube (MWCNT) composites. The electrochemical properties of the sensors have been investigated and show that the surface area is increased upon addition of the MWCNT-PS layer. Furthermore, a plasma activation process is used to partially remove the PS and expose the MWCNTs. This results in a huge increase in the electrochemical area and opens up the possibility of binding biomolecules to the MWCNT wall. The MWCNTs have been functionalized covalently with a model antibody (rabbit IgG). The biosensors have been tested using amperometric techniques and show detection limits comparable to standard techniques such as ELISA.

  7. Reactive infiltration in fabricating silicon carbide composites for electronic packaging

    Science.gov (United States)

    Xiao, Liming

    The silicon carbide (SiC) composite is a promising material to improve thermal dissipation and thermal expansion matching for electronic packaging, but its wide application has been greatly hindered by the high fabrication cost. To address this cost issue, two new reactive infiltration methods have been proposed and developed to fabricate SiC composite in a net-shape manner. They are Method 1--locally magnesium-enhanced infiltration and Method 2--globally carbon-enhanced infiltration. In Method 1, a magnesium wetting agent was strategically inserted at the interface between SiC powder and Al-Si alloy. The molten Al-Si alloy was assisted by chemical reaction to infiltrate into the porous SiC powder in an inert atmosphere sealed in a quartz tube or a steel cup. The infiltration kinetics was characterized by measuring the infiltration weight gain with respect to time. It was found that the infiltration kinetics could be divided into three stages: infiltration initiation, rapid infiltration, and slow infiltration, and most of the weight gain occurred in the rapid infiltration stage. The rapid infiltration was due to the magnesium-silicon oxide reaction and the magnesium accumulation at the infiltration front. Modeling of the infiltration kinetics showed the magnesium dilution increased the dynamic contact angle, which in turn decreased the infiltration rate. The SiC oxidation, Mg content and temperature were shown to be important factors affecting the infiltration. In Method 2, a carbon wetting agent is coated globally on every SiC particle. To accomplish this coating, a slip casting, drying, curing and carbonization process was developed. A crucibleless infiltration method was designed to fabricate SiC composites in an open atmosphere protected by nitrogen. The temperature change of SiC preform during infiltration was monitored to determine the infiltration kinetics. The silicon-carbon reaction was found to create a spontaneous infiltration of molten Si or molten Al

  8. Growth of cluster assembled ZnO film by nanocluster beam deposition technique

    Energy Technology Data Exchange (ETDEWEB)

    Halder, Nilanjan [Department of Physics, Manipal University Jaipur, Jaipur-303007 (India)

    2015-06-24

    ZnO is considered as one of the most promising material for optoelectronic devices. The present work emphasizes production of cluster assembled ZnO films by a UHV nanocluster beam deposition technique where the nanoclusters were produced in a laser vaporization cluster source. The microstructural and the optical properties of the ZnO nanocluster film deposited were investigated. As the wet chemical processes are not compatible with current solid state methods of device fabrication, therefore alternative UHV technique described in the paper is the need of the hour.

  9. Fabrication of Biosensor Based on Polyaniline/Gold Nanorod Composite

    Directory of Open Access Journals (Sweden)

    Uğur Tamer

    2011-01-01

    Full Text Available This present paper describes a new approach to fabricate a new amperometric sensor for the determination of glucose. Polyaniline (PANI film doped with colloidal gold nanorod particles has been used to immobilize glucose oxidase by glutaraldehyde. The polyaniline/gold nanorod composite structure gave an excellent matrix for enzyme immobilization due to the large specific surface area and higher electroactivity. The composite has been characterized by cyclic voltammetry (CV, scanning electron microscopy (SEM, and surface-enhanced Raman spectroscopy (SERS. The SERS spectrum of the surface-immobilized glucose oxidase and the spectrum of the native enzyme indicate that the main feature of the native structure of glucose oxidase was conserved after being immobilized on the polymer matrix. The amperometric response was measured as a function of concentration of glucose at a potential of 0.6 V versus Ag/AgCl in 0.1 M phosphate buffer at pH 6.4. Linear range of the calibration curve was from 17.6 μM to 1 mM with a sensitivity of 13.8 μA⋅mM−1⋅cm−2 and a limit of detection (LOD of 5.8 μM. The apparent Michaelis-Menten constant KM was calculated as 1.0 mM and the response time was less than 3 seconds.

  10. Fabrication and characterization of magnetic composite membrane pressure sensor

    KAUST Repository

    Khan, Mohammed Asadullah

    2016-04-20

    This paper describes a magnetic field powered pressure sensor, which comprises a coil array and a magnetic composite membrane. The composite membrane is made by embedding a ribbon of the amorphous soft magnetic alloy Vitrovac®, in a 17 mm x 25 mm x 1.5 mm Polydimethylsiloxane (PDMS) layer. PDMS is chosen for its low Young\\'s modulus and the amorphous alloy for its high permeability. The membrane is suspended 1.5 mm above a 17x19 array of microfabricated planar coils. The coils are fabricated by patterning a 620 nm thick gold layer. Each coil occupies an area of 36000 μm2 and consists of 14 turns. The sensor is tested by subjecting it to pressure and simultaneously exciting it by a 24 A/m, 100 kHz magnetic field. A pressure change from 0 kPa to 5.1 kPa, results in a 5400 ppm change in the voltage output.

  11. Synthesis and Doping of Ligand-Protected Atomically-Precise Metal Nanoclusters

    KAUST Repository

    Aljuhani, Maha A.

    2016-05-01

    Rapidly expanding research in nanotechnology has led to exciting progress in a versatile array of applications from medical diagnostics to catalysis. This success resulted from the manipulation of the desired properties of nanomaterials by controlling their size, shape, and composition. Among the most thriving areas of research about nanoparticle is the synthesis and doping of the ligand-protected atomically-precise metal nanoclusters. In this thesis, we developed three different novel metal nanoclusters, such as doped Ag29 with five gold (Au) atoms leading to enhance its quantum yield with remarkable stability. We also developed half-doped (alloyed) cluster of Ni6 nanocluster with molybdenum (Mo). This enabled enhanced stability and better catalytic activity. The third metal nanocluster that we synthesized was Au28 nanocluster by using di-thiolate as the ligand stabilizer instead of mono-thiolate. The new metal clusters obtained have been characterized by spectroscopic, electrochemical and crystallographic methods.

  12. Performance of Plain Woven Jute Fabric-Reinforced Polyester Matrix Composite in Multilayered Ballistic System

    Directory of Open Access Journals (Sweden)

    Sergio Neves Monteiro

    2018-02-01

    Full Text Available The ballistic performance of plain woven jute fabric-reinforced polyester matrix composites was investigated as the second layer in a multilayered armor system (MAS. Volume fractions of jute fabric, up to 30 vol %, were mixed with orthophthalic polyester to fabricate laminate composites. Ballistic tests were conducted using high velocity 7.62 mm ammunition. The depth of penetration caused by the bullet in a block of clay witness, simulating a human body, was used to evaluate the MAS ballistic performance according to the international standard. The fractured materials after tests were analyzed by scanning electron microscopy (SEM. The results indicated that jute fabric composites present a performance similar to that of the much stronger Kevlar™, which is an aramid fabric laminate, as MAS second layer with the same thickness. The mechanism of this similar ballistic behavior as well as the comparative advantages of the jute fabric composites over the Kevlar™ are discussed.

  13. Controle de la fabrication des composites par injection sur renforts

    Science.gov (United States)

    Lebel, Francois

    Liquid Composite Molding (LCM) is an increasingly used class of processes to manufacture high performance composites. A multiscale study is presented in this thesis in order to better understand the fundamental physics of impregnation and air entrapment phenomena in dual scale fibrous reinforcements and thus propose practical solutions for process control engineers. First of all, an experimental setup is developed to study the saturation of fibrous reinforcements, at the macroscopic scale, during the Resin Transfer Molding (RTM). This setup is used to determine some key parameters of the part filling step and industrial post-filling strategies (mold bleeding and consolidation) that control the impregnation quality of fibrous reinforcements. These key parameters are identified using three series of experiments. These parameters are the flow front velocity, the inlet mold pressure and the bleeding flow rate. The analyses in these three series of experiments are based on an ASTM standard procedure for void content determination in the composite parts by carbonization (also called loss on ignition (LOI)). These three series of experiments have related a posteriori the key parameters of LCM processes to phenomena of void formation, migration and dissolution in composite parts made of E-glass non crimp fabric (NCF) and vinyl ester resin. The second part of this thesis aims to investigate, at the mesoscopic and microscopic scale, the impregnation mechanisms of fibrous reinforcements during LCM processes. This analysis focuses more specifically on wicking phenomenon in fiber tows and in fibrous laminates, namely here stacks of non crimp fabric plies. This experimental study is carried out to better understand the physics which explain that the impregnation velocity is one of the key parameters that control the quality of composite parts manufactured by LCM processes. This analysis also aims to identify the structural features of fiber tows and fibrous reinforcements that

  14. Experimental Investigation on Mechanical Properties of Hemp/E-Glass Fabric Reinforced Polyester Hybrid Composites

    Directory of Open Access Journals (Sweden)

    M R SANJAY

    2016-09-01

    Full Text Available This research work has been focusing on Hemp fibers has an alternative reinforcement for fiber reinforced polymer composites due to its eco-friendly and biodegradable characteristics. This work has been carried out to evaluate the mechanical properties of hemp/E-glass fabrics reinforced polyester hybrid composites. Vacuum bagging method was used for the preparation of six different kinds of hemp/glass fabrics reinforced polyester composite laminates as per layering sequences. The tensile, flexural, impact and water absorption tests of these hybrid composites were carried out experimentally according to ASTM standards. It reveals that an addition of E-glass fabrics with hemp fabrics can increase the mechanical properties of composites and decrease the water absorption of the hybrid composites.

  15. The influence of stiffeners on axial crushing of glass-fabric-reinforced epoxy composite shells

    Directory of Open Access Journals (Sweden)

    A. Vasanthanathan

    2017-01-01

    Full Text Available A generic static and impact experimental procedure has been developed in this work aimed at improving the stability of glass fabric reinforced epoxy shell structures by bonding with axial stiffeners. Crashworthy structures fabricated from composite laminate with stiffeners would offer energy absorption superior to metallic structures under compressive loading situations. An experimental material characterisation of the glass fabric reinforced epoxy composite under uni-axial tension has been carried out in this study. This work provides a numerical simulation procedure to describe the static and dynamic response of unstiffened glass fabric reinforced epoxy composite shell (without stiffeners and stiffened glass fabric reinforced epoxy composite shell (with axial stiffeners under static and impact loading using the Finite Element Method. The finite element calculation for the present study was made with ANSYS®-LS-DYNA® software. Based upon the experimental and numerical investigations, it has been asserted that glass fabric reinforced epoxy shells stiffened with GFRP stiffeners are better than unstiffened glass fabric reinforced epoxy shell and glass fabric reinforced epoxy shell stiffened with aluminium stiffeners. The failure surfaces of the glass fabric reinforced epoxy composite shell structures tested under impact were examined by SEM.

  16. Tensile and Flexural Properties of Cement Composites Reinforced with Flax Nonwoven Fabrics

    Directory of Open Access Journals (Sweden)

    Josep Claramunt

    2017-02-01

    Full Text Available The aim of this study is to develop a process to produce high-performance cement-based composites reinforced with flax nonwoven fabrics, analyzing the influence of the fabric structure—thickness and entanglement—on mechanical behavior under flexural and tensile loadings. For this purpose, composite with flax nonwoven fabrics with different thicknesses were first prepared and their cement infiltration was evaluated with backscattered electron (BSE images. The nonwoven fabrics with the optimized thickness were then subjected to a water treatment to improve their stability to humid environments and the fiber-matrix adhesion. For a fixed thickness, the effect of the nonwoven entanglement on the mechanical behavior was evaluated under flexural and direct tension tests. The obtained results indicate that the flax nonwoven fabric reinforcement leads to cement composites with substantial enhancement of ductility.

  17. Tensile and Flexural Properties of Cement Composites Reinforced with Flax Nonwoven Fabrics

    Science.gov (United States)

    Claramunt, Josep; Ventura, Heura; Fernández-Carrasco, Lucía J; Ardanuy, Mònica

    2017-01-01

    The aim of this study is to develop a process to produce high-performance cement-based composites reinforced with flax nonwoven fabrics, analyzing the influence of the fabric structure—thickness and entanglement—on mechanical behavior under flexural and tensile loadings. For this purpose, composite with flax nonwoven fabrics with different thicknesses were first prepared and their cement infiltration was evaluated with backscattered electron (BSE) images. The nonwoven fabrics with the optimized thickness were then subjected to a water treatment to improve their stability to humid environments and the fiber-matrix adhesion. For a fixed thickness, the effect of the nonwoven entanglement on the mechanical behavior was evaluated under flexural and direct tension tests. The obtained results indicate that the flax nonwoven fabric reinforcement leads to cement composites with substantial enhancement of ductility. PMID:28772573

  18. Dopant ink composition and method of fabricating a solar cell there from

    Science.gov (United States)

    Loscutoff, Paul; Wu, Kahn; Molesa, Steven Edward

    2015-03-31

    Dopant ink compositions and methods of fabricating solar cells there from are described. A dopant ink composition may include a cross-linkable matrix precursor, a bound dopant species, and a solvent. A method of fabricating a solar cell may include delivering a dopant ink composition to a region above a substrate. The dopant ink composition includes a cross-linkable matrix precursor, a bound dopant species, and a solvent. The method also includes baking the dopant ink composition to remove a substantial portion of the solvent of the dopant ink composition, curing the baked dopant ink composition to cross-link a substantial portion of the cross-linkable matrix precursor of the dopant ink composition, and driving dopants from the cured dopant ink composition toward the substrate.

  19. Dopant ink composition and method of fabricating a solar cell there from

    Energy Technology Data Exchange (ETDEWEB)

    Loscutoff, Paul; Wu, Kahn; Molesa, Steven Edward

    2017-10-25

    Dopant ink compositions and methods of fabricating solar cells there from are described. A dopant ink composition may include a cross-linkable matrix precursor, a bound dopant species, and a solvent. A method of fabricating a solar cell may include delivering a dopant ink composition to a region above a substrate. The dopant ink composition includes a cross-linkable matrix precursor, a bound dopant species, and a solvent. The method also includes baking the dopant ink composition to remove a substantial portion of the solvent of the dopant ink composition, curing the baked dopant ink composition to cross-link a substantial portion of the cross-linkable matrix precursor of the dopant ink composition, and driving dopants from the cured dopant ink composition toward the substrate.

  20. Calculation of the relative uniformity coefficient on the green composites reinforced with cotton and hemp fabric

    Science.gov (United States)

    Baciu, Florin; Hadǎr, Anton; Sava, Mihaela; Marinel, Stǎnescu Marius; Bolcu, Dumitru

    2016-06-01

    In this paper it is studied the influence of discontinuities on elastic and mechanical properties of green composite materials (reinforced with fabric of cotton or hemp). In addition, it is studied the way variations of the volume f the reinforcement influences the elasticity modulus and the tensile strength for the studied composite materials. In order to appreciate the difference in properties between different areas of the composite material, and also the dimensions of the defective areas, we have introduced a relative uniformity coefficient with which the mechanical behavior of the studied composite is compared with a reference composite. To validate the theoretical results we have obtained we made some experiments, using green composites reinforced with fabric, with different imperfection introduced special by cutting the fabric.

  1. Enhanced impact properties of cementitious composites reinforced with pultruded flax/polymeric matrix fabric

    Directory of Open Access Journals (Sweden)

    Magdi El-Messiry

    2017-09-01

    Full Text Available Fiber reinforced concrete (FRC has become increasingly applied in civil engineering in the last decades. Natural fiber fabric reinforced cement composites are considered to prevent damage resulting from an impact loading on the cementite plate. Flax woven fabric that has a high energy absorption capability was chosen. To increase the interfacial shear properties, the fabric was pultruded with different matrix properties that affect the strength and toughness of the pultruded fabric. In this study, three fabric structures are used to increase the anchoring of the cement in the fabric. The compressive strength and the impact energy were measured. The results revealed that pultruded fabric reinforced cement composite (PFRC absorbs much more impact energy. PFRC under impact loading has more micro cracks, while plain cement specimen shows brittle failure. The compressive test results of PFRC indicate that flax fiber fabric polymer enhanced compressive strength remarkably. Fiber reinforcement is a very effective in improving the impact resistance of PFRC. The study defines the influence factors that control the energy dissipation of the composite, which are the hardness of the polymer and the fabric cover factor. Significant correlation between impact energy and compressive strength was proved.

  2. Flax fabric reinforced arylated soy protein composites: A brittle-matrix behaviour

    CSIR Research Space (South Africa)

    Kumar, R

    2012-05-01

    Full Text Available Biocomposites were successfully prepared by the reinforcement of soy protein isolate (SPI) with different weight fractions of woven flax fabric. The flax-fabric-reinforced SPI-based composites were then arylated with 2,2-diphenyl-2-hydroxyethanoic...

  3. On possibility of fabrication of monolith composite materials on niobium carbide base

    International Nuclear Information System (INIS)

    Ploshkin, V.V.; Ul'yanina, I.Yu.; Filonenko, V.P.

    1984-01-01

    An attempt was made to fabricate the composite material on niobium carbide base possessing the elevated heat resistance, erosion and chemical resistance in special media, as well as capable of withstanding sufficient thermal shocks. Powder of niobium carbide of 10 μm fraction was used as base material, the powder of pure copper of 10...12 μm fraction - as binder. It was shown that samples of composite mateiral on niobium carbide base fabricated by the method of hydrostatic pressing possessed the minimal porosity as compared to samples fabricated by usual methods of powder metallurgy. The basic phases of composite material-copper and niobium carbide - distribute uniformly over sample cross-section and don't interact with each other under any conditions. The fabricated composite material possesses sufficient thermal shock resistance and isn't subjected to brittle fracture

  4. Polyimide Composites Properties of RTM370 Fabricated by Vacuum Assisted Resins Transfer Molding (VARTM)

    Science.gov (United States)

    Chuang, Kathy C.; Criss, Jim M.; Mintz, Eric A.

    2011-01-01

    RTM370 imide resin based on 2,3,3 ,4 -biphenyl dianhydride ( a-BPDA), 3,4 -oxydianinline (3,4 -ODA) with 4-phenylethynylphthalic (PEPA) endcap has shown to exhibit high Tg (370 C) and low melt viscosity (10-30 poise) at 280 C with a pot-life of 1-2 h. Previously, RTM370 resin has been fabricated into composites with T650-35 carbon fabrics by resin transfer molding (RTM) successfully. RTM370 composites exhibit excellent mechanical properties up to 327 C (620 F), and outstanding property retention after aging at 288 C (550 F) for 1000 hrs. In this presentation, RTM 370 composites will be fabricated by vacuum assisted resins transfer molding (VARTM), using vacuum bags without mold. The mechanical properties of RTM370 composites fabricated by VARTM will be compared to those of RTM370 made by RTM.

  5. Mechanical properties of uniaxial natural fabric Grewia tilifolia reinforced epoxy based composites: Effects of chemical treatment

    CSIR Research Space (South Africa)

    Jayaramudu, J

    2014-07-01

    Full Text Available The effects of chemical treatment on the mechanical, morphological, and chemical resistance properties of uniaxial natural fabrics, Grewia tilifolia/epoxy composites, were studied. In order to enhance the interfacial bonding between the epoxy matrix...

  6. Composite Properties of RTM370 Polyimide Fabricated by Vacuum Assisted Resin Transfer Molding (VARTM)

    Science.gov (United States)

    Chuang, Kathy C.; Criss, James M.; Mintz, Eric A.; Shonkwiler, Brian; McCorkle, Linda S.

    2011-01-01

    RTM370 imide resin based on 2,3,3?,4?-biphenyl dianhydride (a-BPDA), 3,4'-oxydianinline (3,4'-ODA) with the 4-phenylethynylphthalic (PEPA) endcap has been shown to exhibit a high cured T(sub g) (370 C) and low melt viscosity (10-30 poise) at 280 C with a pot-life of 1-2 h. Previously, RTM370 resin has been successfully fabricated into composites reinforced with T650-35 carbon fabrics by resin transfer molding (RTM). RTM370 composites exhibit excellent mechanical properties up to 327?C (620?F), and outstanding property retention after aging at 288?C (550?F) for 1000 h. In this work, RTM370 composites were fabricated by vacuum assisted resin transfer molding (VARTM), using vacuum bags on a steel plate. The mechanical properties of RTM370 composites fabricated by VARTM are compared to those prepared by RTM.

  7. Polyester fabric coated with Ag/ZnO composite film by magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Xiaohong, E-mail: yxhong1981_2004@126.com [Key Laboratory of Eco-Textiles, Ministry of Education, Jiangnan University, Wuxi 214122, Jiangsu (China); Faculty of Clothing and Design, Minjiang University, Fuzhou 350121, Fujian (China); Xu, Wenzheng, E-mail: xwz8199@126.com [Key Laboratory of Eco-Textiles, Ministry of Education, Jiangnan University, Wuxi 214122, Jiangsu (China); Huang, Fenglin, E-mail: windhuang325@163.com [Key Laboratory of Eco-Textiles, Ministry of Education, Jiangnan University, Wuxi 214122, Jiangsu (China); Chen, Dongsheng, E-mail: mjuchen@126.com [Faculty of Clothing and Design, Minjiang University, Fuzhou 350121, Fujian (China); Wei, Qufu, E-mail: qfwei@jiangnan.edu.cn [Key Laboratory of Eco-Textiles, Ministry of Education, Jiangnan University, Wuxi 214122, Jiangsu (China)

    2016-12-30

    Highlights: • Ag/ZnO composite film was successfully deposited on polyester fabric by magnetron sputtering technique. • Ag film was easily oxidized into Ag{sub 2}O film in high vacuum oxygen environment. • The zinc film coated on the surface of Ag film before RF reactive sputtering could protect the silver film from oxidation. • Polyester fabric coated with Ag/ZnO composite film can obtained structural color. • The anti-ultraviolet and antistatic properties of polyester fabric coated with Ag/ZnO composite film all were good. - Abstract: Ag/ZnO composite film was successfully deposited on polyester fabric by using direct current (DC) magnetron sputtering and radio frequency (RF) magnetron reaction sputtering techniques with pure silver (Ag) and zinc (Zn) targets. X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) were used to examine the deposited film on the fabric. It was found that the zinc film coated on Ag film before RF reactive sputtering could protect the silver film from oxidation. Anti-ultraviolet property and antistatic property of the coated samples using different magnetron sputtering methods were also investigated. The experimental results showed that Ag film was oxidized into in Ag{sub 2}O film in high vacuum oxygen environment. The deposition of Zn film on the surface of the fabric coated with Ag film before RF reactive sputtering, could successfully obtained Ag/ZnO composite film, and also generated structural color on the polyester fabric.

  8. Wear behavior of light-cured resin composites with bimodal silica nanostructures as fillers.

    Science.gov (United States)

    Wang, Ruili; Bao, Shuang; Liu, Fengwei; Jiang, Xiaoze; Zhang, Qinghong; Sun, Bin; Zhu, Meifang

    2013-12-01

    To enhance wear behavior of resin composites, bimodal silica nanostructures including silica nanoparticles and silica nanoclusters were prepared and proposed as fillers. The silica nanoclusters, a combination of individually dispersed silica nanoparticles and their agglomerations, with size distribution of 0.07-2.70 μm, were fabricated by the coupling reaction between amino and epoxy functionalized silica nanoparticles, which were obtained by the surface modification of silica nanoparticles (~70 nm) using 3-aminopropyl triethoxysilane (APTES) and 3-glycidoxypropyl trimethoxysilane (GPS) as coupling agents, respectively. Silica nanoparticles and nanoclusters were then silanized with 3-methacryloxypropyl trimethoxysilane (γ-MPS) to prepare composites by mixing with bisphenol A glycerolate dimethacrylate (Bis-GMA) and tri (ethylene glycol) dimethacrylate (TEGDMA). Experimental composites with various filler compositions were prepared and their wear behaviors were assessed in this work. The results suggested that composites with increasing addition of silica nanoparticles in co-fillers possessed lower wear volume and smoother worn surface. Particularly, the composite 53:17 with the optimum weight ratio of silica nanoparticles and silica nanoclusters presented the excellent wear behavior with respect to that of the commercial Esthet-X, although the smallest wear volume was achieved by Z350 XT. The introduction of bimodal silica nanostructures as fillers might provide a new sight for the design of resin composites with significantly improved wear resistance. Crown Copyright © 2013. All rights reserved.

  9. Solvent-free fabrication of thermally conductive insulating epoxy composites with boron nitride nanoplatelets as fillers.

    Science.gov (United States)

    Wang, Zifeng; Fu, Yuqiao; Meng, Wenjun; Zhi, Chunyi

    2014-01-01

    A solvent-free method for the fabrication of thermally conductive epoxy-boron nitride (BN) nanoplatelet composite material is developed in this study. By this method, polymer composites with nearly any filler fractions can be easily fabricated. The maximum thermal conductivity reaches 5.24 W/mK, which is 1,600% improvement in comparison with that of pristine epoxy material. In addition, the as-fabricated samples exhibit excellent overall performances with great mechanical property and thermal stability well preserved.

  10. Antifungal activity of fabrics knitted by metalized Silver/Polyester composite yarn

    Science.gov (United States)

    Özkan, İ.; Duru Baykal, P.

    2017-10-01

    In this study, antifungal properties of fabric knitted from metalized silver/polyester composite yarn were investigated. Intermingling is an alternative technique for yarn blending process. Yarns having different features can be combined by feeding the same intermingling jet. This process is defined as commingling. In the study, intermingling process was used to produce metalized silver/polyester composite yarn. Commingled yarns were knitted to single jersey fabrics by IPM brand sample type circular knitting machine. Antifungal activity test was applied to samples against Aspergillus Niger according to AATCC 30 test procedure. It has been identified that the application provides antifungal activity to fabric.

  11. Mechanical Properties Of 3D-Structure Composites Based On Warp-Knitted Spacer Fabrics

    Directory of Open Access Journals (Sweden)

    Chen Si

    2015-06-01

    Full Text Available In this paper, the mechanical properties (compression and impact behaviours of three-dimension structure (3D-structure composites based on warp-knitted spacer fabrics have been thoroughly investigated. In order to discuss the effect of fabric structural parameters on the mechanical performance of composites, six different types of warp-knitted spacer fabrics having different structural parameters (such as outer layer structure, diameter of spacer yarn, spacer yarn inclination angle and thickness were involved for comparison study. The 3D-structure composites were fabricated based on a flexible polyurethane foam. The produced composites were characterised for compression and impact properties. The findings obtained indicate that the fabric structural parameters have strong influence on the compression and impact responses of 3D-structure composites. Additionally, the impact test carried out on the 3D-structure composites shows that the impact loads do not affect the integrity of composite structure. All the results reveal that the product exhibits promising mechanical performance and its service life can be sustained.

  12. Structures and properties of the polyacrylonitrile fabric coated with ZnO-Ag composites

    International Nuclear Information System (INIS)

    Shao Dongfeng; Gao Dawei; Wei Qufu; Zhu Hong; Tao Lizhen; Ge Mingqiao

    2010-01-01

    The polyacrylonitrile (PAN) fabric coated with ZnO-Ag composite was achieved by hydrothermal synthesis techniques and photochemical method. The PAN fabrics coated with ZnO-Ag composite were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR), UV-vis spectrophotometer and fabric induced static tester, respectively. The SEM images revealed the formation of the coating aggregates on the fiber surface. The FT-IR spectra and XRD patterns revealed the chemical structures of the coatings on the PAN fabrics. The results of UV-vis test showed that there was an obvious increase in ultraviolet resistant properties after coating. The antistatic properties results revealed the improvement in the antistatic performance of coated fabrics, attributed to the superior electrical and optical properties of ZnO and Ag.

  13. The expanding universe of thiolated gold nanoclusters and beyond.

    Science.gov (United States)

    Jiang, De-en

    2013-08-21

    Thiolated gold nanoclusters form a universe of their own. Researchers in this field are constantly pushing the boundary of this universe by identifying new compositions and in a few "lucky" cases, solving their structures. Such solved structures, even if there are only few, provide important hints for predicting the many identified compositions that are yet to be crystallized or structure determined. Structure prediction is the most pressing issue for a computational chemist in this field. The success of the density functional theory method in gauging the energetic ordering of isomers for thiolated gold clusters has been truly remarkable, but to predict the most stable structure for a given composition remains a great challenge. In this feature article from a computational chemist's point of view, the author shows how one understands and predicts structures for thiolated gold nanoclusters based on his old and new results. To further entertain the reader, the author also offers several "imaginative" structures, claims, and challenges for this field.

  14. Fabrication of low specific resistance ceramic carbon composites by ...

    Indian Academy of Sciences (India)

    2017-10-15

    Oct 15, 2017 ... In this work, ceramic carboncomposites were fabricated using alumina–clay slurries with addition of glucose as a soluble carbon source. Morphology ofthe sintered samples was characterized by field emission gun (FEG) electron microscopy. Phase analysis was done by X-raydiffraction (XRD). Electrical ...

  15. Assessing the Suitability of Woven Fabric and Composite Textile ...

    African Journals Online (AJOL)

    This art studio experimental study explored the suitability of woven cotton fabric as alternative material for creating pictorial designs for murals based on the batik, tie-and-dye, screen printing, appliqué and embroidery techniques in textiles. While painted and sculpted murals abound in Ghana, the study found textile murals a ...

  16. Fabrication and characterization of PDLLA/pyrite composite bone ...

    Indian Academy of Sciences (India)

    pyrite (Zi-Ran-Tong, FeS2) scaffold containing 5–20% of pyrite was fabricated by particle leaching combined with the thermal-induced phase separation method. Pyrite (FeS2, named as Zi-Ran-Tong in Chinese medicine), as a traditional ...

  17. Application of ionizing radiation for metal nanoclusters synthesis

    International Nuclear Information System (INIS)

    Smietanko-Chmielewska, D.K.; Chmielewski, A.G.; Warsaw University of Technology, Warsaw

    2011-01-01

    Complete text of publication follows. Possibility of ionizing radiation application in nanotechnology has been observed from very beginning when this field of science and technology was named. The lithography is based on electron and ion beam applications, and metal clusters synthesis by radiation induced radicals was reported many years ago. International Atomic Energy Agency was the first organization which has started coordinated programs on radiation applications in nanotechnology which are being continued in the frame of regional cooperation project RER8014. Some of applications led to patented technical solutions. Then review papers and chapters in the books have been published. The main applications beside of lithography deal with metal nanoclusters and nano-composites synthesis. Polymer composites containing metal nanoparticles have attracted a great interest due to their unique chemical and physical properties. 'Green' chemistry promotes application of natural fibers in such structures, among them cellulose is one of the most frequently used. However, cellulose fabric have ability to absorb moisture, so under certain conditions of humidity and temperature they can be subjected to microbial attack. One of the most popular and best known antibacterial agents is silver, which serves as a potential antibacterial material acting against an exceptionally broad spectrum of bacteria including activity against antibiotic-resistant bacteria. Silver nanoparticles (Ag NPs) were grown at the cellulose fibers surface by direct reduction of AgNO 3 with electron beam (EB) application. The big field of development concerns nano composites, possibility of e/X units application enlarge this possibility to industrial scale product manufacturing. Acknowledgement: This work was supported by the IAEA, regional project RER/8/014 and by the Ministry of Science and Higher Education, project DPN/W14/IAEA/2009.

  18. Hydrothermal Synthesis of Nanoclusters of ZnS Comprised on Nanowires.

    Science.gov (United States)

    Ibupoto, Zafar Hussain; Khun, Kimleang; Liu, Xianjie; Willander, Magnus

    2013-09-09

    Cetyltrimethyl ammonium bromide cationic (CTAB) surfactant was used as template for the synthesis of nanoclusters of ZnS composed of nanowires, by hydrothermal method. The structural and morphological studies were performed by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM) techniques. The synthesized ZnS nanoclusters are composed of nanowires and high yield on the substrate was observed. The ZnS nanocrystalline consists of hexagonal phase and polycrystalline in nature. The chemical composition of ZnS nanoclusters composed of nanowires was studied by X-ray photo electron microscopy (XPS). This investigation has shown that the ZnS nanoclusters are composed of Zn and S atoms.

  19. Hydrothermal Synthesis of Nanoclusters of ZnS Comprised on Nanowires

    Directory of Open Access Journals (Sweden)

    Magnus Willander

    2013-09-01

    Full Text Available Cetyltrimethyl ammonium bromide cationic (CTAB surfactant was used as template for the synthesis of nanoclusters of ZnS composed of nanowires, by hydrothermal method. The structural and morphological studies were performed by using X-ray diffraction (XRD, scanning electron microscopy (SEM and high resolution transmission electron microscopy (HRTEM techniques. The synthesized ZnS nanoclusters are composed of nanowires and high yield on the substrate was observed. The ZnS nanocrystalline consists of hexagonal phase and polycrystalline in nature. The chemical composition of ZnS nanoclusters composed of nanowires was studied by X-ray photo electron microscopy (XPS. This investigation has shown that the ZnS nanoclusters are composed of Zn and S atoms.

  20. Mechanical properties of waste paper/jute fabric reinforced polyester resin matrix hybrid composites.

    Science.gov (United States)

    Das, Sekhar

    2017-09-15

    Hybrid composites were prepared with jute fabric and un-shredded newspaper in polyester resin matrix. The experiment was designed 1:2 weights ratio jute and unshredded newspaper to have 42 (w/w)% fibre content hybrid composites and two different sequences jute/paper/jute and paper/jute/paper of waste newspaper and jute fabric arrangement. Reinforcing material is characterized by chemically, X-ray diffraction methods, Fourier transform infrared spectroscopy and tensile testing. The tensile, flexural and interlaminar shear strength and fracture surface morphology of composites were evaluated and compared. It was found that tensile and flexural properties of the hybrid composite are higher than that of pure paper-based composite but less than pure woven jute composite. The hybridization effect of woven jute fabric and layering pattern effect on mechanical properties of newspaper/woven jute fabric hybrid composites were studied. The test results of composites were analyzed by one-way ANOVA (α=0.05), it showed significant differences among the groups. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Studies on the mechanical properties of woven jute fabric reinforced poly(l-lactic acid composites

    Directory of Open Access Journals (Sweden)

    G.M. Arifuzzaman Khan

    2016-01-01

    Full Text Available Development of ecofriendly biocomposites to replace non-biodegradable synthetic fiber composites is the main objective of this study. To highlight the biocomposites as a perfect replacement, the plain woven jute fabric (WJF reinforced poly(l-lactic acid (PLLA composites were prepared by the hot press molding method. The influence of woven structure and direction on the mechanical properties i.e. tensile, flexural and impact properties was investigated. The average tensile strength (TS, tensile modulus (TM, flexural strength (FS, flexural modulus (FM, and impact strength (IS of untreated woven jute composite (in warp direction were improved about 103%, 211%, 95.2%, 42.4% and 85.9%, respectively and strain at maximum tensile stress for composite samples was enhanced by 11.7%. It was also found that the strengths and modulus of composites in warp direction are higher than those in weft direction. WJF composites in warp and weft directions presented superior mechanical properties than non-woven jute fabric (NWJF composites. Chemical treatment of jute fabric through benzoylation showed a positive effect on the properties of composites. Morphological studies by SEM demonstrated that better adhesion between the treated fabric and PLLA was achieved.

  2. Fabrication of carbon film composites for high-strength structures

    Science.gov (United States)

    Preiswerk, P. R.; Lippman, M.

    1972-01-01

    Physical and mechanical properties of fiber composite materials consisting of carbon films are described. Application of carbon film structural composites for constructing microwave filters or optical instruments is proposed. Applications in aerospace and architectural structures for high strength and low density properties are discussed.

  3. XFEM modelling of open-hole woven fabric kenaf composite plates

    Science.gov (United States)

    Ahmad, H.; Supar, K.; Romanye, A. H.

    2017-09-01

    Woven fabric kenaf composites offer superior specific stiffness (and strength), renewable, better handling and relatively cheaper than commercial fiber composites counterparts. Current work is carried out to predict the notched strength of woven fabric kenaf fiber reinforced polymer (KFRP) composite plates containing a circular hole. Extended finite element framework is implemented within two-dimensional ABAQUS CAE to implement traction-separation as a constitutive model. The parameter used in constitutive modeling are unnotched strength, σ0 (which is measured independently) and a single fracture energy value, Gc* was used throughout all modeling framework series. The modeling series covers a range of lay-up types woven fabric kenaf composites lay-ups with notch size of 2.5 mm, 5 mm and 10 mm at the plate centerline. The prediction in current study showed reasonable agreement with experimental datasets.

  4. Feasibility and Manufacturing Considerations of Hemp Textile Fabric Utilized in Pre-Impregnated Composites

    Science.gov (United States)

    Osusky, Gregory

    This study investigates the fabrication and mechanical properties of semicontinuous, hemp fiber reinforced thermoset composites. This research determines if off-the-shelf refined woven hemp fabric is suitable as composite reinforcement using resin pre-impregnated method. Industrial hemp was chosen for its low cost, low resource input as a crop, supply chain from raw product to refined textile and biodegradability potential. Detail is placed on specimen fabrication considerations. Lab testing of tension and compression is conducted and optimization considerations are examined. The resulting composite is limited in mechanical properties as tested. This research shows it is possible to use woven hemp reinforcement in pre-impregnated processed composites, but optimization in mechanical properties is required to make the process commercially practical outside niche markets.

  5. Fabrication and measurement of a flexoelectric micro-pyramid composite

    OpenAIRE

    Wenbin Huang; Longlong Shu; Seol Ryung Kwon; Shujun Zhang; Fuh-Gwo Yuan; Xiaoning Jiang

    2014-01-01

    A fabrication method by combining precision mechanical dicing and wet etching was developed to prepare micro-pyramid structures based on (Ba0.67Sr0.33)TiO3 ceramics. The effective piezoelectric properties of flexoelectric pyramid structures in ten micrometers scale were investigated and measured through converse flexoelectric effect. The scaling effect of the flexoelectric response was demonstrated as the structure size shrinks down. The results do suggest the great potential of flexoelectric...

  6. Effect of Sericin on Mechanical Behavior of Composite Material Reinforced by Silk Woven Fabric

    Science.gov (United States)

    Kimura, Teruo; Ino, Haruhiro; Hanada, Koji; Katori, Sigetaka

    Recent, attention has been given to shift from glass fibers and carbon fibers to natural fibers for FRP composites for the goal of protecting the environment. This paper concerned with the application of silk fabric for composite materials. Polypropylene (PP) was used for the matrix material and the silk fabric composites were molded using a compression molding method. Especially, the effect of sericin on mechanical behaviors of composite materials was discussed. Good adhesion between silk and PP was obtained by removing the sericin existing around the fibroin. The tensile modulus of composite decreased with decreasing the sericin because of the flexibility of silk fibers without sericin. In particular, the higher Izod impact value was obtained for the composites containing the silk fibers without sericin.

  7. Analysis of woven and braided fabric reinforced composites

    Science.gov (United States)

    Naik, Rajiv A.

    1994-01-01

    A general purpose micromechanics analysis that discretely models the yarn architecture within the textile repeating unit cell, was developed to predict overall, three dimensional, thermal and mechanical properties. This analytical technique was implemented in a user-friendly, personal computer-based, windows compatible code called Textile Composite Analysis for Design (TEXCAD). TEXCAD was used to analyze plain, 5-harness satin, and 8-harness satin weave composites along with 2-D braided and 2x2, 2-D triaxial braided composites. The calculated overall stiffnesses correlated well with available 3-D finite element results and test data for both the woven and the braided composites. Parametric studies were performed to investigate the effects of yarn size on the yarn crimp and the overall thermal and mechanical constants for plain weave composites. The effects of braid angle were investigated for the 2-D braided composites. Finally, the effects of fiber volume fraction on the yarn undulations and the thermal and mechanical properties of 2x2, 2-D triaxial braided composites were also investigated.

  8. The Effect of Pre-Tension on Deformation Behaviour of Natural Fabric Reinforced Composite

    Directory of Open Access Journals (Sweden)

    Paulė BEKAMPIENĖ

    2011-03-01

    Full Text Available In the fiber-reinforced composites industry together with the promotion of environmental friendly production, synthetic materials are attempted to be replaced by renewable, biodegradable and recyclable materials. The most important challenge is to improve strength and durability of these materials. Matrix that supports the fiber-reinforcement in composite generally is brittle and deformation causes fragmentation of the matrix. Pre-tension of reinforcement is a well-known method to increase tensile strength of woven material. The current study develops the idea to use pre-tension of woven fabric in order to improve quality and strength properties of the obtained composite. Natural (cotton fiber and synthetic (glass fiber woven fabrics were investigated. The pressure forming operation was carried out in order to study clamping imposed strain variation across the surface of woven fabric. The uniaxial tension test of single-layer composite specimens with and without pre-tension was performed to study the effect of pre-tension on strength properties of composite. The results have shown that pre-tension imposed by clamping is an effective method to improve the quality of shaped composite parts (more smoothed contour is obtained and to increase the strength properties of composite reinforced by woven natural fabric. After pre-tension the tensile strength at break increased in 12 % in warp direction, in 58 % in weft direction and in 39 % in bias direction.http://dx.doi.org/10.5755/j01.ms.17.1.250

  9. Method of Fabricating NASA-Standard Macro-Fiber Composite Piezoelectric Actuators

    Science.gov (United States)

    High, James W.; Wilkie, W. Keats

    2003-01-01

    The NASA Macro-Fiber Composite actuator is a flexible piezoelectric composite device designed for controlling vibrations and shape deformations in high performance aerospace structures. A complete method for fabricating the standard NASA Macro-Fiber Composite actuator is presented in this document. When followed precisely, these procedures will yield devices with electromechanical properties identical to the standard actuator manufactured by NASA Langley Research Center.

  10. Chairside fabricated fiber-reinforced composite fixed partial denture

    Directory of Open Access Journals (Sweden)

    Sufyan Garoushi

    2007-01-01

    Full Text Available The advances in the materials and techniques for adhesive dentistry have allowed the development of non-invasive or minimally invasive approaches for replacing a missing tooth in those clinical situations when conservation of adjacent teeth is needed. Good mechanical and cosmetic/aesthetic properties of fiber-reinforced composite (FRC, with good bonding properties with composite resin cement and veneering composite are needed in FRC devices. Some recent studies have shown that adhesives of composite resins and luting cements allow diffusion of the adhesives to the FRC framework of the bridges. By this so-called interdiffusion bonding is formed [1]. FRC bridges can be made in dental laboratories or chairside. This article describes a clinical case of chairside (directly made FRC Bridge, which was used according to the principles of minimal invasive approach. Treatment was performed by Professor Vallittu from the University of Turku, Finland.

  11. Failure analysis of woven and braided fabric reinforced composites

    Science.gov (United States)

    Naik, Rajiv A.

    1994-01-01

    A general purpose micromechanics analysis that discretely models the yarn architecture within the textile repeating unit cell was developed to predict overall, three dimensional, thermal and mechanical properties, damage initiation and progression, and strength. This analytical technique was implemented in a user-friendly, personal computer-based, menu-driven code called Textile Composite Analysis for Design (TEXCAD). TEXCAD was used to analyze plain weave and 2x2, 2-D triaxial braided composites. The calculated tension, compression, and shear strengths correlated well with available test data for both woven and braided composites. Parametric studies were performed on both woven and braided architectures to investigate the effects of parameters such as yarn size, yarn spacing, yarn crimp, braid angle, and overall fiber volume fraction on the strength properties of the textile composite.

  12. Fabrication and characterization of polymer composites for endodontic use.

    Science.gov (United States)

    Alhashimi, R; Mannocci, F; Foxton, R; Deb, S

    2014-06-01

    To develop a low-density polyethylene-hydroxyapatite (HA-PE) composite with properties tailored to function as a potential root canal filling material. Hydroxyapatite and polyethylene mixed with strontium oxide as a radiopacifier were extruded from a single screw extruder fitted with an appropriate die to form fibres. The composition of the composite was optimized with clinical handling and placement in the canal being the prime consideration. The fibres were characterized using infrared spectroscopy (FTIR), and their thermal properties determined using differential scanning calorimetry (DSC). The tensile strength and elastic modulus of the composite fibres and gutta-percha were compared, dry and after 1 month storage in simulated body fluid (SBF), using a universal testing machine. The radiopacity of the fibres was determined using digital radiography. The interaction of the composites with eugenol was evaluated and compared with gutta-percha. Data of the tensile test were submitted to two-way anova and Bonferroni tests (P composites ranged between 110.5 and 111.2 °C, whereas gutta-percha exhibited a melting point at 52 °C. The tensile strength and elastic modulus of the silanated HA/PE composites were significantly higher than those of gutta-percha (P composites were unchanged. Radiological evaluations demonstrated that silanated HA/PE fibres were sufficiently radiopaque. Promising materials for endodontic applications have been developed, offering relevant benefits over the traditional materials in terms of mechanical and chemical properties. © 2013 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  13. Mechanical Properties of Glass Fiber Composites Reinforced by Textile Fabric

    OpenAIRE

    Macanovskis, Arturs; Krasnikovs, Andrejs; Kononova, Olga; Harjkova, Galina; Yevstignejevs, Vladislav

    2015-01-01

    Interest to structural application of textile reinforced polymer matrix composite materials (CM) is growing during last years. In different branches of machine building, aerospace, automotive and others industries we can find structural elements preferably be produced using such reinforcement. At the same time, such materials are exhibiting elastic and strength properties scatter. In the framework of the present investigation, we observe yarn penetrated by a resin in a composite as a reinforc...

  14. Polyester fabric coated with Ag/ZnO composite film by magnetron sputtering

    Science.gov (United States)

    Yuan, Xiaohong; Xu, Wenzheng; Huang, Fenglin; Chen, Dongsheng; Wei, Qufu

    2016-12-01

    Ag/ZnO composite film was successfully deposited on polyester fabric by using direct current (DC) magnetron sputtering and radio frequency (RF) magnetron reaction sputtering techniques with pure silver (Ag) and zinc (Zn) targets. X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) were used to examine the deposited film on the fabric. It was found that the zinc film coated on Ag film before RF reactive sputtering could protect the silver film from oxidation. Anti-ultraviolet property and antistatic property of the coated samples using different magnetron sputtering methods were also investigated. The experimental results showed that Ag film was oxidized into in Ag2O film in high vacuum oxygen environment. The deposition of Zn film on the surface of the fabric coated with Ag film before RF reactive sputtering, could successfully obtained Ag/ZnO composite film, and also generated structural color on the polyester fabric.

  15. Mercuric iodide composite films using polyamide, polycarbonate and polystyrene fabricated by casting

    International Nuclear Information System (INIS)

    Ugucioni, J.C.; Ghilardi Netto, T.; Mulato, M.

    2010-01-01

    Mercuric iodide (HgI 2 ) composite films were obtained by using the casting technique. Insulator polymers such as polyamide, polycarbonate and polystyrene were mixed to HgI 2 crystallites forming a final sub-millimeter thick self-standing film. Fabrication temperature varied from 10 to 100 o C, and total fabrication time reached at most 5 min. The larger the fabrication temperature, the thinner the film and the smaller its electrical resistivity. Electrical characterization was performed in the dark, under UV illumination and under mammographic X-ray exposure. The final properties of the films are discussed and related to fabrication conditions. The optimized composite film might be a better candidate for use as X-ray detector for medical imaging, in place of the single HgI 2 crystalline device.

  16. Fabrication and measurement of a flexoelectric micro-pyramid composite

    Science.gov (United States)

    Huang, Wenbin; Shu, Longlong; Ryung Kwon, Seol; Zhang, Shujun; Yuan, Fuh-Gwo; Jiang, Xiaoning

    2014-12-01

    A fabrication method by combining precision mechanical dicing and wet etching was developed to prepare micro-pyramid structures based on (Ba0.67Sr0.33)TiO3 ceramics. The effective piezoelectric properties of flexoelectric pyramid structures in ten micrometers scale were investigated and measured through converse flexoelectric effect. The scaling effect of the flexoelectric response was demonstrated as the structure size shrinks down. The results do suggest the great potential of flexoelectric micro pyramids as an alternative to lead-free piezoelectric material.

  17. Fabrication and measurement of a flexoelectric micro-pyramid composite

    Directory of Open Access Journals (Sweden)

    Wenbin Huang

    2014-12-01

    Full Text Available A fabrication method by combining precision mechanical dicing and wet etching was developed to prepare micro-pyramid structures based on (Ba0.67Sr0.33TiO3 ceramics. The effective piezoelectric properties of flexoelectric pyramid structures in ten micrometers scale were investigated and measured through converse flexoelectric effect. The scaling effect of the flexoelectric response was demonstrated as the structure size shrinks down. The results do suggest the great potential of flexoelectric micro pyramids as an alternative to lead-free piezoelectric material.

  18. Investigation Of Sound Absorption Properties Of Bark Cloth Nonwoven Fabric And Composites

    OpenAIRE

    Rwawiire Samson; Tomkova Blanka; Gliscinska Eulalia; Krucinska Izabella; Michalak Marina; Militky Jiri; Jabbar Abdul

    2015-01-01

    The quest for sound-absorbing materials that are not only environmentally friendly, but also sustainable is the foremost reason for natural fibre-acoustic materials. Bark cloth is a natural non-woven fabric that is largely produced from Ficus trees. An exploratory investigation of bark cloth a non-woven material and its reinforcement in epoxy polymer composites has been fabricated and investigated for the sound absorption properties so as to find the most suitable applications and also to see...

  19. Effects of Crimped Fiber Paths on Mixed Mode Delamination Behaviors in Woven Fabric Composites

    Science.gov (United States)

    2016-09-01

    Mode Delamination Behaviors in Woven Fabric Composites 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR( S ) Paul V. Cavallaro...compression using experiments and XFEM modeling. The cylinder was constructed of unidirectional ( non - woven ) tapes oriented along the hoop and...NUWC-NPT Technical Report 12,216 1 September 2016 Effects of Crimped Fiber Paths on Mixed-Mode Delamination Behaviors in Woven Fabric

  20. Fabrication of naturel pumice/hydroxyapatite composite for biomedical engineering.

    Science.gov (United States)

    Komur, Baran; Lohse, Tim; Can, Hatice Merve; Khalilova, Gulnar; Geçimli, Zeynep Nur; Aydoğdu, Mehmet Onur; Kalkandelen, Cevriye; Stan, George E; Sahin, Yesim Muge; Sengil, Ahmed Zeki; Suleymanoglu, Mediha; Kuruca, Serap Erdem; Oktar, Faik Nuzhet; Salman, Serdar; Ekren, Nazmi; Ficai, Anton; Gunduz, Oguzhan

    2016-07-07

    We evaluated the Bovine hydroxyapatite (BHA) structure. BHA powder was admixed with 5 and 10 wt% natural pumice (NP). Compression strength, Vickers micro hardness, Fourier transform infrared spectroscopy, scanning electron microscopy (SEM) and X-ray diffraction studies were performed on the final NP-BHA composite products. The cells proliferation was investigated by MTT assay and SEM. Furthermore, the antimicrobial activity of NP-BHA samples was interrogated. Variances in the sintering temperature (for 5 wt% NP composites) between 1000 and 1300 °C, reveal about 700 % increase in the microhardness (~100 and 775 HV, respectively). Composites prepared at 1300 °C demonstrate the greatest compression strength with comparable result for 5 wt% NP content (87 MPa), which are significantly better than those for 10 wt% and those that do not include any NP (below 60 MPa, respectively). The results suggested the optimal parameters for the preparation of NP-BHA composites with increased mechanical properties and biocompatibility. Changes in micro-hardness and compression strength can be tailored by the tuning the NP concentration and sintering temperature. NP-BHA composites have demonstrated a remarkable potential for biomedical engineering applications such as bone graft and implant.

  1. FABRICATION AND CHARACTERIZATION OF CARBON COMPOSITE FROM COCONUT SHELL CARBON

    Directory of Open Access Journals (Sweden)

    Meytij Jeanne Rampe

    2011-11-01

    Full Text Available Structure and chemical composition of coconut shell carbon with polyvinyl alcohol (PVA as the stimulant through the observation of TG-DTA, SEM-EDS and FTIR has been studied. The process was carried out by calcining coconut shell charcoal at the temperature of 873 and 1023 K under Nitrogen flow, then mixed with polyvinyl alcohol (PVA under composition of 2.5 to 7.5% (wt in water solvent. The growing of carbon composite structure was observed by heating the samples in Argon gas of 1673 K, the rate of temperature was 10 K/min in 3 h. The products were then analyzed by TG-DTA, SEM-EDS, FTIR and XRD. The result showed that the products were in uniform particle sizes of micrometer dimensions and spherical particles shape, with average content of C element was 97.44% (wt, aromatic character and semi-crystalline structure.

  2. Fabrication of ZrC–SiC composites using zirconium salt as raw materials

    Directory of Open Access Journals (Sweden)

    Yan Ma

    2014-12-01

    Full Text Available A ZrC–SiC matrix was fabricated by means of in situ reaction method, using zirconium salt, silicon powder and phenolic resin as raw materials. The performances of zirconium salt determined the possibility of ZrC–SiC matrix fabricated using them. The reactions were completed at a relatively low temperature (∼1500 °C. With this concept to produce a ZrC–SiC matrix costs can be reduced. Three-dimensional needle Cf/ZrC–SiC composites were successfully fabricated via the polymer infiltration and pyrolysis (PIP process using zirconium salt, silicon powder and phenolic resin as raw materials.

  3. Advancement in conductive cotton fabrics through in situ polymerization of polypyrrole-nanocellulose composites.

    Science.gov (United States)

    Hebeish, A; Farag, S; Sharaf, S; Shaheen, Th I

    2016-10-20

    Current research was undertaking with a view to innovate a new approach for development of conductive - coated textile materials through coating cotton fabrics with nanocellulose/polypyrrole composites. The study was designed in order to have a clear understanding of the role of nanocellulose as well as modified composite thereof under investigation. It is anticipated that incorporation of nanocellulose in the pyrrole/cotton fabrics/FeCl3/H2O system would form an integral part of the composites with mechanical, electrical or both properties. Three different nanocellulosic substrates are involved in the oxidation polymerization reaction of polypyrrole (Ppy) in presence of cotton fabrics. Polymerization was subsequently carried out by admixing at various ratios of FeCl3 and pyrrole viz. Ppy1, Ppy2 and pp3. The conductive, mechanical and thermal properties of cotton fabrics coated independently with different nanocellulose/polypyrrole were investigated. FTIR, TGA, XRD, SEM and EDX were also used for further characterization. Results signify that, the conductivity of cotton fabrics increases exponentially with increasing the dose of pyrrole and oxidant irrespective of nanocellulose substrate used. While, the mechanical properties of cotton fabrics are not significantly affected by the oxidant treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Mechanical and dielectric properties of epoxy/dicyclopentadiene bisphenol cyanate ester/glass fabric composites

    Directory of Open Access Journals (Sweden)

    2008-02-01

    Full Text Available The impact and flexural strengths of epoxy-dicyclopentadiene bisphenol cyanate ester (EP-DCPDCE hybrid thermoset as well as the interlaminar shear strength (ILSS and flexural strength of the composites consisting of the hybrid thermoset and glass fabric were studied. It is found that the addition of epoxy resin (EP-51 can improve the mechanical properties, particularly, the impact strength of DCPDCE matrix and the ILSS of glass fabric reinforced composites. The improvements of the mechanical properties were obvious when the content of EP-51 is from 15 to 30 wt%. The investigations of the interphase of composites by scanning electron microscope (SEM and dynamic mechanical analysis (DMA confirm the improvement of mechanical properties of the composites. However the addition of EP-51 has negative effects on the thermal and dielectric property of the composites.

  5. Characterization of Three-Dimensional Printed Composite Scaffolds Prepared with Different Fabrication Methods

    Directory of Open Access Journals (Sweden)

    Szlązak K.

    2016-06-01

    Full Text Available An optimal method for composites preparation as an input to rapid prototyping fabrication of scaffolds with potential application in osteochondral tissue engineering is still needed. Scaffolds in tissue engineering applications play a role of constructs providing appropriate mechanical support with defined porosity to assist regeneration of tissue. The aim of the presented study was to analyze the influence of composite fabrication methods on scaffolds mechanical properties. The evaluation was performed on polycaprolactone (PCL with 5 wt% beta-tricalcium phosphate (TCP scaffolds fabricated using fused deposition modeling (FDM. Three different methods of PCL-TCP composite preparation: solution casting, particles milling, extrusion and injection were used to provide material for scaffold fabrication. The obtained scaffolds were investigated by means of scanning electron microscope, x-ray micro computed tomography, thermal gravimetric analysis and static material testing machine. All of the scaffolds had the same geometry (cylinder, 4×6 mm and fiber orientation (0/60/120°. There were some differences in the TCP distribution and formation of the ceramic agglomerates in the scaffolds. They depended on fabrication method. The use of composites prepared by solution casting method resulted in scaffolds with the best combination of compressive strength (5.7±0.2 MPa and porosity (48.5±2.7 %, both within the range of trabecular bone.

  6. Fabrication of low specific resistance ceramic carbon composites by ...

    Indian Academy of Sciences (India)

    2017-09-07

    Sep 7, 2017 ... the produced carbon is responsible for low electrical specific resistance of the ceramic carbon composites. References. [1] Takahashi M, Adachi K, Menchavez R L and Fuji M 2006 J. Mater. Sci. 41 1965. [2] ShuKMandTuGC2003Int. J. Machine Tools Manufacture43. 845. [3] Mikeska K R 1997 United States ...

  7. Multi-Scale Modeling the Mechanical Properties of Biaxial Weft Knitted Fabrics for Composite Applications

    Science.gov (United States)

    Abghary, Mohammad Javad; Nedoushan, Reza Jafari; Hasani, Hossein

    2017-08-01

    In this paper a multi-scale numerical model for simulating the mechanical behavior of biaxial weft knitted fabrics produced based on 1×1 rib structure is presented. Fabrics were produced on a modern flat knitting machine using polyester as stitch yarns and nylon as straight yarns. A macro constitutive equation was presented to model the fabric mechanical behavior as a continuum material. User defined material subroutines were provided to implement the constitutive behavior in Abaqus software. The constitutive equation needs remarkable tensile tests on the fabric as the inputs. To solve this drawbacks meso scale modeling of the fabric was used to predict stress-strain curves of the fabric in three different directions (course, wale and 45°). In these simulations only the yarn properties are needed. To evaluate the accuracy of the proposed macro and meso models, fabric tensile behavior in 22.5 and 67.5° directions were simulated by the calibrated macro model and compared with experimental results. Spherical deformation was also simulated by the multi scale model and compared with experimental results. The results showed that the multi-scale modeling can successfully predict the tensile and spherical deformation of the biaxial weft knitted fabric with least required experiments. This model will be useful for composite applications.

  8. TiB2 reinforced aluminum based in situ composites fabricated by stir casting

    International Nuclear Information System (INIS)

    Chen, Fei; Chen, Zongning; Mao, Feng; Wang, Tongmin; Cao, Zhiqiang

    2015-01-01

    In this study, a new technique involving mechanical stirring at the salts/aluminum interface was developed to fabricate TiB 2 particulate reinforced aluminum based in situ composites with improved particle distribution. Processing parameters in terms of stirring intensity, stirring duration and stirring start time were optimized according to the microstructure and mechanical properties evaluation. The results show that, the first and last 15 min of the entire 60 min holding are of prime importance to the particle distribution of the final composites. When applying 180 rpm (revolutions per minute) stirring at the salts/aluminum interface in these two intervals, a more uniform microstructure can be achieved and the Al-4 wt% TiB 2 composite thus produced exhibits superior mechanical performance. Synchrotron radiation X-ray computed tomography (SR-CT) was used to give a full-scale imaging of the particle distribution. From the SR-CT results, the in situ Al–xTiB 2 composites (x=1, 4 and 7, all in wt%) fabricated by the present technique are characterized by fine and clean TiB 2 particles distributed uniformly throughout the Al matrix. These composites not only have higher yield strength (σ 0.2 ) and ultimate tensile strength (UTS), but also exhibit superior ductility, with respect to the Al–TiB 2 composites fabricated by the conventional process. The σ 0.2 and UTS of the Al–7TiB 2 composite in the present work, are 260% and 180% higher than those of the matrix. A combined mechanism was also presented to interpret the improvements in yield strength of the composites as influenced by their microstructures and processing history. The predicted values are in good agreement with the experimental results, strongly supporting the strengthening mechanism we proposed. Fractography reveals that the composites thus fabricated, follow ductile fracture mechanism in spite of the presence of stiff reinforcements

  9. Fabrication of slag-glass composite with controlled porosity

    Directory of Open Access Journals (Sweden)

    Ranko Adziski

    2008-06-01

    Full Text Available The preparation and performance of porous ceramics made from waste materials were investigated. Slag from thermal electrical plant Kakanj (Bosnia and Herzegovina with defined granulations: (0.500÷0.250 mm; (0.250÷0.125 mm; (0.125÷0.063 mm; (0.063÷0.045 mm and 20/10 wt.% of the waste TV screen glass with a granulation <0.063 mm were used for obtaining slag-glass composites with controlled porosity. The one produced from the slag powder fraction (0.125÷0.063 mm and 20 wt.% TV screen glass, sintered at 950°C/2h, was considered as the optimal. This system possesses open porosity of 26.8±1.0%, and interconnected pores with the size of 250–400 μm. The values of E-modulus and bending strength of this composite were 10.6±0.6 GPa and 45.7±0.7 MPa, respectively. The coefficient of thermal expansion was 8.47·10-6/°C. The mass loss in 0.1M HCl solution after 30 days was 1.2 wt.%. The permeability and the form coefficient of the porous composite were K0=0.12 Da and C0=4.53·105 m-1, respectively. The porous composite shows great potential to be used as filters, diffusers for water aeration, dust collectors, acoustic absorbers, etc.

  10. Practical Considerations of Design, Fabrication and Tests for Composite Materials,

    Science.gov (United States)

    1982-09-01

    that c < o (1 - 2a/w) as in Fig 6. IMPACT DAMAGE IN COMPOSITES Traditionally pendulum impact tests such as Izod and Charpy tests have been used to...more concern with the residual mechanical properties under realistic loading than with the energy absorption measured by conventional pendulum impact...cracks longer than about 20 mm in torsion pendulum experiments at about 5% of the failure strain, and they show that this is about the same level of

  11. Fabrication and performances of AI/CuO nano composite films for ignition application

    Science.gov (United States)

    Li, Yong; Gao, Yun; Jia, Xin; Zhou, Bin; Shen, Rui-Qi

    2015-07-01

    In an effort to explore the application possibility of composite films in ignition field, Al/CuO was fabricated on semiconductor bridge (SCB) chip by ion beam sputtering technique. Surface morphology and elemental composition of the composite films were analysed by scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). Spatial size and duration of the products was detected with the open-air combustion experiment. The results showed that the prepared composite films surface is smooth, flat, and uniform. Element weight ratio meets the design requirements. And the chemical reaction of the Al/CuO nCFs improves output performances of ignition chip.

  12. Possibility of superradiance by magnetic nanoclusters

    International Nuclear Information System (INIS)

    Yukalov, V I; Yukalova, E P

    2011-01-01

    The possibility of realizing spin superradiance by an assembly of magnetic nanoclusters is analyzed. The known obstacles for realizing such a coherent radiation by magnetic nanoclusters are their large magnetic anisotropy, strong dephasing dipole interactions, and an essential nonuniformity of their sizes. In order to give a persuasive conclusion, a microscopic theory is developed, providing an accurate description of nanocluster spin dynamics. It is shown that, despite the obstacles, it is feasible to organize such a setup that magnetic nanoclusters would produce strong superradiant emission

  13. Multilayered ceramic/metal composites by extrusion freeform fabrication

    Science.gov (United States)

    Kasichainula, Sridhar

    Metal layers within a laminar ceramic can improve damage tolerance of ceramics by arresting large cracks either by ductile bridging or by crack deflection at the ceramic/metal interface, which will allow engineers to design reliable ceramics for structural applications. At low volume fractions of the metal ductile bridging is not very effective, mainly owing to decreased distance between the crack tip and next ceramic layer. Significant increase in the energy absorption during fracture can come from delamination, but depends on the interfacial fracture resistance. A two-fold increase in energy absorption is realized in the case of glass-ceramic/silver laminates prepared by extrusion freeform fabrication. Interfacial fracture energy for glass-ceramic/silver is found to be 100 J/m2 in comparison to 15 J/m2 for glass-ceramic/SiC, which should explain the sporadic crack deflection in notched four-point bend. For a short beam flexural test shear failure is more favorable in four-point than in three-point bending. In four-point tests, the shear stresses between the outer and inner loading pins can precipitate shear delamination prior to tensile cracking of the layers. Damage modes under low velocity impact tests are similar to four-point bend showing delamination as primary energy dissipation mechanism.

  14. Fabrication and Water Treatment Application of Carbon Nanotubes (CNTs)-Based Composite Membranes: A Review.

    Science.gov (United States)

    Ma, Lining; Dong, Xinfa; Chen, Mingliang; Zhu, Li; Wang, Chaoxian; Yang, Fenglin; Dong, Yingchao

    2017-03-18

    Membrane separation technology is widely explored for various applications, such as water desalination and wastewater treatment, which can alleviate the global issue of fresh water scarcity. Specifically, carbon nanotubes (CNTs)-based composite membranes are increasingly of interest due to the combined merits of CNTs and membrane separation, offering enhanced membrane properties. This article first briefly discusses fabrication and growth mechanisms, characterization and functionalization techniques of CNTs, and then reviews the fabrication methods for CNTs-based composite membranes in detail. The applications of CNTs-based composite membranes in water treatment are comprehensively reviewed, including seawater or brine desalination, oil-water separation, removal of heavy metal ions and emerging pollutants as well as membrane separation coupled with assistant techniques. Furthermore, the future direction and perspective for CNTs-based composite membranes are also briefly outlined.

  15. Fabrication and Water Treatment Application of Carbon Nanotubes (CNTs-Based Composite Membranes: A Review

    Directory of Open Access Journals (Sweden)

    Lining Ma

    2017-03-01

    Full Text Available Membrane separation technology is widely explored for various applications, such as water desalination and wastewater treatment, which can alleviate the global issue of fresh water scarcity. Specifically, carbon nanotubes (CNTs-based composite membranes are increasingly of interest due to the combined merits of CNTs and membrane separation, offering enhanced membrane properties. This article first briefly discusses fabrication and growth mechanisms, characterization and functionalization techniques of CNTs, and then reviews the fabrication methods for CNTs-based composite membranes in detail. The applications of CNTs-based composite membranes in water treatment are comprehensively reviewed, including seawater or brine desalination, oil-water separation, removal of heavy metal ions and emerging pollutants as well as membrane separation coupled with assistant techniques. Furthermore, the future direction and perspective for CNTs-based composite membranes are also briefly outlined.

  16. Friction and Wear Behavior of Carbon Fabric-Reinforced Epoxy Composites

    Science.gov (United States)

    Şahin, Y.; De Baets, Patrick

    2017-12-01

    Besides intrinsic material properties, weight/energy savings and wear performance play an important role in the selection of materials for any engineering application. The tribological behavior of carbon fabric-reinforced epoxy composites produced by molding technique was investigated using a reciprocating pin-on-plate configuration. It was shown that the wear rate considerably decreased (by a factor of approx. 8) with the introduction of the reinforcing carbon fabric into the epoxy matrix. It was observed that the wear rate of the tested composites increased with an increase in normal load. Moreover, the coefficient of friction for epoxy/steel and composites/steel tribo-pairs was also determined and decreased with increasing load. By means of scanning electron microscopy of the wear tracks, different wear mechanisms such as matrix wear, matrix fatigue and cracking, matrix debris formation for neat epoxy together with fabric/fiber thinning, fabric breakage and fabric/matrix debonding for the reinforced epoxy could be distinguished.

  17. Studies on the mechanical properties of woven jute fabric reinforced poly(l-lactic acid) composites

    OpenAIRE

    G.M. Arifuzzaman Khan; M. Terano; M.A. Gafur; M. Shamsul Alam

    2016-01-01

    Development of ecofriendly biocomposites to replace non-biodegradable synthetic fiber composites is the main objective of this study. To highlight the biocomposites as a perfect replacement, the plain woven jute fabric (WJF) reinforced poly(l-lactic acid) (PLLA) composites were prepared by the hot press molding method. The influence of woven structure and direction on the mechanical properties i.e. tensile, flexural and impact properties was investigated. The average tensile strength (TS), te...

  18. METHOD OF MANUFACTURING A COMPOSITE STRUCTURE INCLUDING A TEXTILE FABRIC ASSEMBLY

    DEFF Research Database (Denmark)

    2017-01-01

    of manufacturing a composite structure (10). The method may comprise providing a form (8) that has a shape corresponding to a desired shape of an internal cavity in the composite structure (10) to be manufactured. The textile fabric assembly (1) is arranged around the form (8), and a curable material (9) is filled......The invention relates to a textile fabric assembly (1) comprising at least two textile layers (2). The textile layers (2) are joined at a plurality of points (3) and/or along a plurality of lines (6) so that they form inner and outer walls, respectively. The invention also relates to a method...... into the at least one inner space (4) between the textile layers (2). The form (8) may be inflatable. Alternatively, the method may comprise arranging the textile fabric assembly (1) around an initial structure and/or mechanically fastened to a surface of an initial structure to be reinforced and then filling...

  19. Shape distortions in fabric reinforced composite products due to processing induced fibre reorientation

    NARCIS (Netherlands)

    Lamers, E.A.D.

    2004-01-01

    Woven fabric reinforced composite materials are typically applied in plate or shell structures, such as ribs, stiffeners and skins. Products of these types can be produced with several production processes. A few examples are diaphragm forming, matched metal die forming and rubber press forming.

  20. Sound absorption properties of porous composites fabricated by a hydrogel templating technique

    NARCIS (Netherlands)

    Rutkevicius, M.; Mehl, G.H.; Paunov, V.N.; Qin, Q.; Rubini, P.A.; Stoyanov, S.D.; Petkov, J.

    2013-01-01

    We have used a hydrogel templating technique followed by the subsequent evaporation of water present to fabricate porous cement and porous PDMS composites, and we have analyzed their sound absorption properties. All experiments were carried out with hydrogel slurries of broad bead size

  1. Composite fuel-cladding tubes and its fabrication

    International Nuclear Information System (INIS)

    Higashinakagawa, Emiko; Kawashima, Junko; Sato, Kanemitsu; Kuwae, Ryosho.

    1985-01-01

    Purpose: To reduce stress-corrosion cracks in a fuel cladding tube. Method: By inserting the sleeve of pure zirconium forming a liner layer into the hollow billet of zirconium alloy as an outer tube, then the composed tube is completed through hot-extruding. Then, the composite tube is pressed, by cold working through several passes, into a tube with a predetermined smaller inner-diameter and thinner wall. Heat treatment is applied between each of the passes of the cold working to recrystallize the zirconium-alloy outer tube substantially, as well as to integrally join the outer tube and the liner layer metal-lurgically. It serves as a buffer for moderating the mechanical interaction with the fuel pellets, whereby the resistance to stress-corrosion cracks can be increased. (Moriyama, K.)

  2. Photoluminescent nanofiber composites, methods for fabrication, and related lighting devices

    Science.gov (United States)

    Guzan, Kimberly A.; Mills, Karmann C.; Han, Li; Davis, James Lynn; Hoertz, Paul G.

    2015-08-04

    A photoluminescent nanofiber composite includes a nanofiber substrate, first luminescent particles, and second luminescent particles. The first luminescent particles are supported by the nanofibers and span at least a portion of a substrate surface, as a layer on the substrate surface, or with some particles located in a bulk of the substrate, or both. The second luminescent particles are disposed on the substrate. The second luminescent particles may be disposed directly on the substrate surface or on the first luminescent particles. The second luminescent particles may be deposited in a pattern of deposition units. The first and second luminescent particles are configured for emitting light of different respective wavelengths in response to excitation by a light beam. One or more surface treatment coatings may be provided at different locations.

  3. The Layer of Kevlar Angle-interlock Woven Fabric Effect on the Tensile Properties of Composite Materials

    Science.gov (United States)

    Xie, Wan-Chen; Guo, Xu-Yi; Yan, Tao; Zhang, Shang-Yong

    2017-09-01

    This article is based on the structure of three-dimensional angle-interlock longitudinal.The 3-layer, 5-layer, 7-layer and 9-layer of angle-interlock 3D fabrics are woven on sample weaving machine respectively with the 1500D Kevlar fiber twist filament produced by United States DuPont. At the same time, Kevlar plain weave fabric is woven, and three, five, seven and nine layers’ fabric are to be compared. In the process of VARTM composite technology, epoxy resin is matrix material, acetone is diluent, triethylene tetramine is curing agent and the five different fabrics are the reinforced materials respectively. Finally, eight different three-dimensional woven fabric composites were prepared. In this paper, the tensile properties of eight kinds of three-dimensional woven fabric composites were tested respectively.Finally, it is concluded that the five-layer angle-interlock woven fabric prepared by Kevlar fiber shows the best tensile property.

  4. FABRICATION AND MATERIAL ISSUES FOR THE APPLICATION OF SiC COMPOSITES TO LWR FUEL CLADDING

    Directory of Open Access Journals (Sweden)

    WEON-JU KIM

    2013-08-01

    Full Text Available The fabrication methods and requirements of the fiber, interphase, and matrix of nuclear grade SiCf/SiC composites are briefly reviewed. A CVI-processed SiCf/SiC composite with a PyC or (PyC-SiCn interphase utilizing Hi-Nicalon Type S or Tyranno SA3 fiber is currently the best combination in terms of the irradiation performance. We also describe important material issues for the application of SiC composites to LWR fuel cladding. The kinetics of the SiC corrosion under LWR conditions needs to be clarified to confirm the possibility of a burn-up extension and the cost-benefit effect of the SiC composite cladding. In addition, the development of end-plug joining technology and fission products retention capability of the ceramic composite tube would be key challenges for the successful application of SiC composite cladding.

  5. Comparison of mechanical properties for polyamide 12 composite-based biomaterials fabricated by fused filament fabrication and injection molding

    Science.gov (United States)

    Rahim, Tuan Noraihan Azila Tuan; Abdullah, Abdul Manaf; Akil, Hazizan Md; Mohamad, Dasmawati

    2016-12-01

    The emergence of 3D printing technology known as fused filament fabrication (FFF) has offered the possibility of producing an anatomically accurate, patient specific implant with more affordable prices. The only weakness of this technology is related to incompatibility and lack of properties of current material to be applied in biomedical. Therefore, this study aims to develop a new, polymer composite-based biomaterial that exhibits a high processability using FFF technique, strong enough and shows acceptable biocompatibility, and safe for biomedical use. Polyamide 12 (PA12), which meets all these requirements was incorporated with two bioceramic fillers, zirconia and hydroxyapatite in order to improve the mechanical and bioactivity properties. The obtained mechanical properties were compared with injection-molded specimens and also a commercial biomedical product, HAPEXTM which is composed of hydroxyapatite and polyethylene. The yield strength and modulus of the PA12 composites increased steadily with increasing filler loading. Although the strength of printed PA12 composites were reduced compared with injection molded specimen, but still higher than HAPEXTM material. The higher surface roughness obtained by printed PA12 was expected to enhance the cell adhesion and provide better implant fixation.

  6. Optimisation of Fabric Reinforced Polymer Composites Using a Variant of Genetic Algorithm

    Science.gov (United States)

    Axinte, Andrei; Taranu, Nicolae; Bejan, Liliana; Hudisteanu, Iuliana

    2017-12-01

    Fabric reinforced polymeric composites are high performance materials with a rather complex fabric geometry. Therefore, modelling this type of material is a cumbersome task, especially when an efficient use is targeted. One of the most important issue of its design process is the optimisation of the individual laminae and of the laminated structure as a whole. In order to do that, a parametric model of the material has been defined, emphasising the many geometric variables needed to be correlated in the complex process of optimisation. The input parameters involved in this work, include: widths or heights of the tows and the laminate stacking sequence, which are discrete variables, while the gaps between adjacent tows and the height of the neat matrix are continuous variables. This work is one of the first attempts of using a Genetic Algorithm ( GA) to optimise the geometrical parameters of satin reinforced multi-layer composites. Given the mixed type of the input parameters involved, an original software called SOMGA (Satin Optimisation with a Modified Genetic Algorithm) has been conceived and utilised in this work. The main goal is to find the best possible solution to the problem of designing a composite material which is able to withstand to a given set of external, in-plane, loads. The optimisation process has been performed using a fitness function which can analyse and compare mechanical behaviour of different fabric reinforced composites, the results being correlated with the ultimate strains, which demonstrate the efficiency of the composite structure.

  7. Mechanical Properties of Composites with Titanium Diboride Fabricated by Spark Plasma Sintering

    Directory of Open Access Journals (Sweden)

    Sulima I.

    2017-09-01

    Full Text Available Microstructure and mechanical properties of the 316L steel composite reinforced with TiB2 phase were examined. The test materials were obtained by SPS technique from powders. From testing of the mechanical properties it follows that the optimum temperature for the fabrication of 316Lsteel-TiB2 composites by SPS is 1100°C. Studies have also proved that the critical content of TiB2 phase in steel matrix should not exceed 6vol%. Above this level, the plastic properties of the composite become unstable and strongly dependent on the time of sintering.

  8. Preliminary investigation of fabrication composite structures by using shape memory alloys

    Science.gov (United States)

    Klein, W.; Dudek, O.

    2017-09-01

    The paper shows method of smart forming composite structures and fundamentals of propose fabrication technology. The presented method is based on innovative 3D printing technics with SMA (Shape Memory Alloy) fibres application. The SMA fibres layout cause an eccentric axial load after thermal activation. The result of this process is composite structures deflection in a predictable direction. The technology demonstrator sample was fabricated as well as numerical simulations were performed in aim of proof of concept. The identification process was developed to determine the layout of SMA fibres. The simulations were performed in MATLAB and ANSYS environment, where the genetic algorithm was used to identify geometrical parameters. The MAC (Modal Assurance Criterion) criterion was used to compare nodal solution with the predefined shape pattern. The simulation results shows possibilities of forming composite structures on the example of deflected beam.

  9. Silver Nanocluster Reparative Effect in Hernioplasty

    Directory of Open Access Journals (Sweden)

    Nikolay M. Anichkov

    2014-06-01

    Full Text Available Background: The acceleration of re-epithelialization and fibroblast differentiation were noted during the experiments with silver nanoclusters (SNs by interrupting the negative development of inflammation at the level of cytokines and promoting a positive course of reparative processes. The aim of this work was to elaborate the experimental model of prosthesis hernioplasty in subcutaneous and intraperitoneal locations of hernioprostheses with SNs, which allowed us to study the course of reparative reactions in all layers of the anterior abdominal wall. Material and Methods: We used a modified hernioprosthesis made from polyester fibers coated with a metal-polymer composition, including the stabilized SN in a concentration of 6.8 and 11.3 mg per 1 g of the hernioprosthesis mesh. During this research we used guinea pigs to study the in vivo tissue reactions. The clinical part of the study included the group of 212 patients who underwent removal of an inguinal hernia. We have identified various factors associated with infectious and toxic effects on the body by determining the level of the serum glutamate-pyruvate-transaminase (SGPT. Results: In implantation of the hernioprostheses, including the high concentration of SN in the laparotomy wound, the exudative component of the inflammation was weakly expressed. It was mostly the proliferative changes that took place. We did not find either CD8-positive type T lymphocytes or PAX5-positive type B activated cells in the exudate. Conclusion: Our research has shown that the use of hernioprostheses that include silver nanoclusters leads to the reduction of inflammation in the exudative phase and to a more favorable course of reparative processes.

  10. Surface-enrichment with hydroxyapatite nanoparticles in stereolithography-fabricated composite polymer scaffolds promotes bone repair.

    Science.gov (United States)

    Guillaume, O; Geven, M A; Sprecher, C M; Stadelmann, V A; Grijpma, D W; Tang, T T; Qin, L; Lai, Y; Alini, M; de Bruijn, J D; Yuan, H; Richards, R G; Eglin, D

    2017-05-01

    Fabrication of composite scaffolds using stereolithography (SLA) for bone tissue engineering has shown great promises. However, in order to trigger effective bone formation and implant integration, exogenous growth factors are commonly combined to scaffold materials. In this study, we fabricated biodegradable composite scaffolds using SLA and endowed them with osteopromotive properties in the absence of biologics. First we prepared photo-crosslinkable poly(trimethylene carbonate) (PTMC) resins containing 20 and 40wt% of hydroxyapatite (HA) nanoparticles and fabricated scaffolds with controlled macro-architecture. Then, we conducted experiments to investigate how the incorporation of HA in photo-crosslinked PTMC matrices improved human bone marrow stem cells osteogenic differentiation in vitro and kinetic of bone healing in vivo. We observed that bone regeneration was significantly improved using composite scaffolds containing as low as 20wt% of HA, along with difference in terms of osteogenesis and degree of implant osseointegration. Further investigations revealed that SLA process was responsible for the formation of a rich microscale layer of HA corralling scaffolds. To summarize, this work is of substantial importance as it shows how the fabrication of hierarchical biomaterials via surface-enrichment of functional HA nanoparticles in composite polymer stereolithographic structures could impact in vitro and in vivo osteogenesis. This study reports for the first time the enhance osteopromotion of composite biomaterials, with controlled macro-architecture and microscale distribution of hydroxyapatite particles, manufactured by stereolithography. In this process, the hydroxyapatite particles are not only embedded into an erodible polymer matrix, as reported so far in the literature, but concentrated at the surface of the structures. This leads to robust in vivo bone formation at low concentration of hydroxyapatite. The reported 3D self-corralling composite

  11. Beryllide pebble fabrication of Be–Zr compositions as advanced neutron multipliers

    Energy Technology Data Exchange (ETDEWEB)

    Nakamichi, Masaru, E-mail: nakamichi.masaru@jaea.go.jp; Kim, Jae Hwan; Ochiai, Kentaro

    2016-11-01

    Highlights: • Fabrication of beryllide pebbles of Be–Zr compositions was conducted from the viewpoint of pebble mass production. • Prototypic Be–Zr beryllides pebbles were successfully fabricated using the plasma-sintered electrodes by the rotating electrode method. • By utilizing plasma-sintered electrodes with high Be and Zr contents, Be{sub 13}Zr pebbles had a high granulation yield of 84%. • The Be{sub 13}Zr pebbles displayed better oxidation properties as compared to pure Be pebbles. - Abstract: Fusion reactors require advanced neutron multipliers with high stability at high temperatures. Beryllium intermetallic compounds (beryllides) have a universally robust potential for high temperature use. Fabrication of beryllide pebbles of Be–Zr compositions was conducted from the viewpoint of pebble mass production. Prototypic pebbles were successfully fabricated using the plasma-sintered electrodes with high Be and Zr contents for enhanced of the thermal shock resistivity of the electrodes during granulation by a rotating electrode method. From the results of granulation examinations, it was revealed that granulation yields varied greatly depending on compositions of the plasma-sintered electrodes themselves. By utilizing plasma-sintered electrodes with high Be and Zr contents, Be{sub 13}Zr pebbles had a high granulation yield of 84%. Moreover, the Be{sub 13}Zr pebbles displayed better oxidation properties as compared to pure Be pebbles.

  12. Processing and Electromagnetic Shielding Properties of Multifunctional Metal Composite Knitted Fabric used as Socks

    Directory of Open Access Journals (Sweden)

    Yu Zhicai

    2016-01-01

    Full Text Available In this research, a type of bamboo charcoal polyester (BC-PET/antibacterial nylon(AN/stainless steel wire (SSW metal composite yarn was prepared with a hollow spindle spinning machine, which using the SSW as the core material, the BC-PET and AN as the outer and inner wrapped yarns, respectively. The wrapping numbers was set at 8.0turns/cm for the produced metal composite yarns. Furthermore, a type of plated knitted fabric was designed and produced by using the automatic jacquard knitting machine. The plated knitted fabric presents the BC-PET/AN/SSW metal composite yarn on the knitted fabric face and the crisscross-section polyester (CSP on the knit back. The effect of lamination numbers and angles on the electromagnetic shielding effectiveness (EMSE were discussed in this study. EMSE measurement showed that the lamination angles will influence the EMSE, but not affect the air permeability. Finally, a novel EM shielding socks was designed with the produced plated knitted fabric. Finally, the performance of thermal resistance and evaporation resistance was also test usingThe sweating guarded hot plate apparatus.

  13. Bio-composites fabricated by sandwiching sisal fibers with polypropylene (PP)

    International Nuclear Information System (INIS)

    Sosiati, H.; Nahyudin, A.; Fauzi, I.; Wijayanti, D. A.; Triyana, K.

    2016-01-01

    Sisal fibers reinforced polypropylene (PP) composites were successfully fabricated using sandwiching sisal fibers with PP sheets. The ratio of fiber and polymer matrix was 50:50 (wt. %). Untreated short and long sisal fibers, and alkali treated short sisal fibers in 6% NaOH at 100°C for 1 and 3 h were used as reinforcement or fillers. A small amount (3 wt. %) of maleic anhydride grafted polypropylene (MAPP) was added as a coupling agent. Scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy were used to characterize the surface morphology and chemical composition of the fibers, respectively. Flexural test of sisal/PP composites was done according to ASTM D 790-02. The results showed that flexural strength of untreated long fiber reinforced composite is much higher than that of the untreated and alkali treated short fibers reinforced composites with and without the addition of MAPP. Alkalization related to fiber surface modification, fiber length/fiber orientation and a composite fabrication technique are important factors in contributing to the fiber distribution within the matrix, the bonding between the fiber and the matrix and the enhancement of flexural strength of the bio-composite.

  14. Bio-composites fabricated by sandwiching sisal fibers with polypropylene (PP)

    Science.gov (United States)

    Sosiati, H.; Nahyudin, A.; Fauzi, I.; Wijayanti, D. A.; Triyana, K.

    2016-04-01

    Sisal fibers reinforced polypropylene (PP) composites were successfully fabricated using sandwiching sisal fibers with PP sheets. The ratio of fiber and polymer matrix was 50:50 (wt. %). Untreated short and long sisal fibers, and alkali treated short sisal fibers in 6% NaOH at 100°C for 1 and 3 h were used as reinforcement or fillers. A small amount (3 wt. %) of maleic anhydride grafted polypropylene (MAPP) was added as a coupling agent. Scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy were used to characterize the surface morphology and chemical composition of the fibers, respectively. Flexural test of sisal/PP composites was done according to ASTM D 790-02. The results showed that flexural strength of untreated long fiber reinforced composite is much higher than that of the untreated and alkali treated short fibers reinforced composites with and without the addition of MAPP. Alkalization related to fiber surface modification, fiber length/fiber orientation and a composite fabrication technique are important factors in contributing to the fiber distribution within the matrix, the bonding between the fiber and the matrix and the enhancement of flexural strength of the bio-composite.

  15. Fabrication, polarization, and characterization of PVDF matrix composites for integrated structural load sensing

    International Nuclear Information System (INIS)

    Haghiashtiani, Ghazaleh; Greminger, Michael A

    2015-01-01

    The focus of this work is to evaluate a new carbon fiber reinforced composite structure with integrated sensing capabilities. In this composite structure, the typical matrix material used for carbon fiber reinforced composites is replaced with the thermoplastic polyvinylidene difluoride (PVDF). Since PVDF has piezoelectric properties, it enables the structure to be used for integrated load sensing. In addition, the electrical conductivity property of the carbon fabric is harnessed to form the electrodes of the integrated sensor. In order to prevent the carbon fiber electrodes from shorting to each other, a thin Kevlar fabric layer is placed between the two carbon fiber electrode layers as a dielectric. The optimal polarization parameters were determined using a design of experiments approach. Once polarized, the samples were then used in compression and tensile tests to determine the effective d 33 and d 31 piezoelectric coefficients. The degree of polarization of the PVDF material was determined by relating the effective d 33 coefficient of the composite to the achieved d 33 of the PVDF component of the composite using a closed form expression. Using this approach, it was shown that optimal polarization of the composite material results in a PVDF component d 33 of 3.2 pC N −1 . Moreover, the Young’s modulus of the composite structure has been characterized. (paper)

  16. Fabrication and biocompatibility of poly(L-lactic acid) and chitosan composite scaffolds with hierarchical microstructures

    Energy Technology Data Exchange (ETDEWEB)

    Lou, Tao, E-mail: taolou72@aliyun.com [College of Chemistry and Chemical Engineering, Qingdao University, Qingdao 266071 (China); Wang, Xuejun [College of Chemistry and Chemical Engineering, Qingdao University, Qingdao 266071 (China); Yan, Xu [College of Physics & Collaborative Innovation Center for Low-Dimensional Nanomaterials and Optoelectronic Devices, Qingdao University, Qingdao 266071 (China); Miao, Yu [Department of Mechanical Engineering, Columbia University, New York, NY 10027 (United States); Long, Yun-Ze, E-mail: yunzelong@163.com [College of Physics & Collaborative Innovation Center for Low-Dimensional Nanomaterials and Optoelectronic Devices, Qingdao University, Qingdao 266071 (China); Yin, Hai-Lei [Department of Osteology, No. 401 Hospital of P. L. A., Qingdao 266071 (China); Sun, Bin [College of Physics & Collaborative Innovation Center for Low-Dimensional Nanomaterials and Optoelectronic Devices, Qingdao University, Qingdao 266071 (China); Song, Guojun [College of Chemistry and Chemical Engineering, Qingdao University, Qingdao 266071 (China)

    2016-07-01

    The scaffold microstructure is crucial to reconstruct tissue normal functions. In this article, poly(L-lactic acid) and chitosan fiber (PLLA/CTSF) composite scaffolds with hierarchical microstructures both in fiber and pore sizes were successfully fabricated by combining thermal induced phase separation and salt leaching techniques. The composite scaffolds consisted of a nanofibrous PLLA matrix with diameter of 50–500 nm, and chitosan fibers with diameter of about 20 μm were homogenously distributed in the PLLA matrix as a microsized reinforcer. The composite scaffolds also had high porosity (> 94%) and hierarchical pore size, which were consisted of both micropores (50 nm–10 μm) and macropores (50–300 μm). By tailoring the microstructure and chemical composition, the mechanical property, pH buffer and protein adsorption capacity of the composite scaffold were improved significantly compared with those of PLLA scaffold. Cell culture results also revealed that the PLLA/CTSF composite scaffolds supported MG-63 osteoblast proliferation and penetration. - Highlights: • Composite scaffolds fabricated by combining thermal induced phase separation and salt leaching techniques • Hierarchical microstructure both in fiber and pore sizes • The scaffold microenvironment facilitates the protein adsorption, cell proliferation and penetration.

  17. Micromechanics Fatigue Damage Analysis Modeling for Fabric Reinforced Ceramic Matrix Composites

    Science.gov (United States)

    Min, J. B.; Xue, D.; Shi, Y.

    2013-01-01

    A micromechanics analysis modeling method was developed to analyze the damage progression and fatigue failure of fabric reinforced composite structures, especially for the brittle ceramic matrix material composites. A repeating unit cell concept of fabric reinforced composites was used to represent the global composite structure. The thermal and mechanical properties of the repeating unit cell were considered as the same as those of the global composite structure. The three-phase micromechanics, the shear-lag, and the continuum fracture mechanics models were integrated with a statistical model in the repeating unit cell to predict the progressive damages and fatigue life of the composite structures. The global structure failure was defined as the loss of loading capability of the repeating unit cell, which depends on the stiffness reduction due to material slice failures and nonlinear material properties in the repeating unit cell. The present methodology is demonstrated with the analysis results evaluated through the experimental test performed with carbon fiber reinforced silicon carbide matrix plain weave composite specimens.

  18. Low-velocity impact behavior of weft-knitted spacer fabrics reinforced composites based on energy absorption

    Science.gov (United States)

    Hasanalizadeh, F.; Dabiryan, H.; Sadighi, M.

    2017-10-01

    Spacer fabrics are prefered to other types of textile fabrics in energy absorption applications due to existence of pile yarns. The particular geometry of spacer fabrics induce to increase resisting out of plane forces such as impact along their thickness. In order to investigate the low-velocity impact behaviour of composites reinforced with spacer fabric, weft-knitted spacer fabrics with different types of pile orientation and pile length were produced using E-glass yarns. Using produced fabrics and epoxy resin, composites samples were provided by hand lay-up method. Low-velocity impact test was carried out on the prepared samples based on a drop-weight method using spherical steel projectile. The indentation at maximum force was extracted as - comparative criteria used to calculate absorbed energy.The results show that the energy absorption of composites increases by increasing the pile density and pile length.

  19. Silica Treatments: A Fire Retardant Strategy for Hemp Fabric/Epoxy Composites

    Directory of Open Access Journals (Sweden)

    Francesco Branda

    2016-08-01

    Full Text Available In this paper, for the first time, inexpensive waterglass solutions are exploited as a new, simple and ecofriendly chemical approach for promoting the formation of a silica-based coating on hemp fabrics, able to act as a thermal shield and to protect the latter from heat sources. Fourier Transform Infrared (FTIR and solid-state Nuclear Magnetic Resonance (NMR analysis confirm the formation of –C–O–Si– covalent bonds between the coating and the cellulosic substrate. The proposed waterglass treatment, which is resistant to washing, seems to be very effective for improving the fire behavior of hemp fabric/epoxy composites, also in combination with ammonium polyphosphate. In particular, the exploitation of hemp surface treatment and Ammonium Polyphosphate (APP addition to epoxy favors a remarkable decrease of the Heat Release Rate (HRR, Total Heat Release (THR, Total Smoke Release (TSR and Specific Extinction Area (SEA (respectively by 83%, 35%, 45% and 44% as compared to untreated hemp/epoxy composites, favoring the formation of a very stable char, as also assessed by Thermogravimetric Analysis (TGA. Because of the low interfacial adhesion between the fabrics and the epoxy matrix, the obtained composites show low strength and stiffness; however, the energy absorbed by the material is higher when using treated hemp. The presence of APP in the epoxy matrix does not affect the mechanical behavior of the composites.

  20. CRADA/NFE-15-05779 Report: Fabrication of Large Area Printable Composite Magnets

    Energy Technology Data Exchange (ETDEWEB)

    Paranthaman, M Parans [ORNL

    2016-09-29

    The technical objective of this technical collaboration phase I proposal was to fabricate large area NdFeB composite magnets at the Oak Ridge National Laboratory Manufacturing Demonstration Facility (ORNL MDF). The goal was to distribute domestically produced isotropic and highly anisotropic high energy density magnetic particles throughout the composite structure in order to enable site specific placement of magnetic phases and minimize the generated waste associated with permanent magnet manufacturing. Big area additive manufacturing (BAAM) and magnet composite fabrication methods were used in this study. BAAM was used to fabricate 65 vol % isotropic MQP NdFeB magnets in nylon polymer matrix. BAAM magnet cylinder was sliced to two magnetic arc-shaped braces. The density of the small BAAM magnet pieces reached 4.1 g/cm3, and the room temperature magnetic properties are: Intrinsic coercivity Hci = 8.8 kOe, Remanence Br = 4.2 kG, and energy product (BH)max = 3.7 MGOe. Also, 1.5” x 1.5” composite magnets with anisotropic MQA NdFeB magnet in a resin were also fabricated under magnetic field. The unaligned sample had a density of 3.75 g/cm3. However, aligned sample possessed a density of 4.27 g/cm3. The magnetic properties didn’t degrade during this process. This study provides a pathway for preparing composite magnets for various magnetic applications.

  1. Fabrication and Tribological Behavior of Stir Cast Mg/B4C Metal Matrix Composites

    Science.gov (United States)

    Singh, Amandeep; Bala, Niraj

    2017-10-01

    Magnesium-based metal matrix composites (MMMCs) have emerged as good alternative material to conventional materials due to their promising advanced properties. In the present work, magnesium-based metal matrix composites (MMMCs) reinforced with B4C particles were successfully fabricated by cost-effective conventional stir casting technique. MMMCs with an average particle size of 63 µm and different weight percent (wt pct) of B4C between 3 and 12 were fabricated. Wear tests were carried out using a pin-on-disk against a steel disk under dry sliding condition at loads that varied between 1 and 5 kg at fixed sliding velocity of 1 m/s. The wear data clearly showed that wear resistance of cast composites is better than that of unreinforced magnesium, which is attributed to dispersion hardening caused by carbide particles. An increase in wt pct of B4C showed the wear resistance and hardness to increase significantly. The wear rate and coefficient of friction increased with an increase in applied load. The SEM and EDS analysis of the worn surfaces delineated the dominant wear mechanisms to be abrasion, adhesion, and oxidation under the different sliding conditions. At lower loads, the wear mechanism transformed from severe abrasive wear in pure magnesium (Mg) to mild abrasion, slight delamination, and oxidation in the Mg/12 wt pct B4C fabricated composite. At higher loads, severe abrasion, adhesion, delamination, and oxidation were found to be the major wear mechanisms in pure Mg, whereas in the Mg/12 wt pct B4C fabricated composites the corresponding mechanisms were mild abrasion, mild adhesion, slight delamination, and oxidation.

  2. Tribological characterization of Al7075–graphite composites fabricated by mechanical alloying and hot extrusion

    International Nuclear Information System (INIS)

    Deaquino-Lara, R.; Soltani, N.; Bahrami, A.; Gutiérrez-Castañeda, E.; García-Sánchez, E.; Hernandez-Rodríguez, M.A.L.

    2015-01-01

    Highlights: • Al7075–graphite composites were synthesized by mechanical alloying and hot extrusion. • Effects of graphite content and milling time on the mechanical and wear properties of fabricated composites were analyzed. • Microstructure and worn surfaces of samples were studied by transmission and scanning electron microscope. • The friction coefficient, wear rate and debris thickness of fabricated composite were investigated. - Abstract: Aluminum matrix composites (AMCs) are candidate materials for aerospace and automotive industry owing to their large elastic modulus, improved strength and low wear rate. A simple method for fabrication of Al7075–graphite composites produced by mechanical alloying (MI) and hot extrusion is described in this paper. Effects of milling time (0–10 h) and graphite concentration (0–1.5 wt.%) on friction, hardness and wear resistance of the AMC were investigated. Wear resistance was determined by the pin-on-disk wear method using 20 and 40 N normal loads at a 0.367 m/s sliding velocity. The worn surfaces were examined by scanning electron microscopy (SEM) to identify distinct topographical features for elucidation of the prevailing wear mechanisms. Experimental results indicated considerable improvement in AMC hardness and wear resistance by adding 1.5% G (wt.) and 10 h of milling, showing homogenous distribution of the reinforcement particles in the Al-base metal-matrix composite. It was found that abrasion is the dominant wear mechanism in all extruded composites, whilst a combination of adhesion and delamination seems to be the governing mechanism for the 7075 aluminum alloy

  3. Fabrication, characterization, and mechanical properties of spark plasma sintered Al–BN nanoparticle composites

    Energy Technology Data Exchange (ETDEWEB)

    Firestein, Konstantin L., E-mail: kosty@firestein.ru [National University of Science and Technology “MISIS”, Leninsky prospect 4, Moscow 119049 (Russian Federation); Steinman, Alexander E.; Golovin, Igor S. [National University of Science and Technology “MISIS”, Leninsky prospect 4, Moscow 119049 (Russian Federation); Cifre, Joan [Universitat de les Illes Balears, Ctra. de Valldemossa, km. 7.5, E-07122 Palma de Mallorca (Spain); Obraztsova, Ekaterina A.; Matveev, Andrei T.; Kovalskii, Andrey M. [National University of Science and Technology “MISIS”, Leninsky prospect 4, Moscow 119049 (Russian Federation); Lebedev, Oleg I. [CRISMAT, UMR 6508, CNRS-ENSICAEN, 6Bd Marechal Juin, 14050 Caen (France); Shtansky, Dmitry V., E-mail: shtansky@shs.misis.ru [National University of Science and Technology “MISIS”, Leninsky prospect 4, Moscow 119049 (Russian Federation); Golberg, Dmitri, E-mail: golberg.dmitri@nims.go.jp [World Premier International Center for Materials Nanoarchitectonics (WPI-MANA) National Institute for Materials Science (NIMS), Namiki 1, Tsukuba, Ibaraki 3050044 (Japan)

    2015-08-26

    Fabrication of high strength yet light and low cost composite materials with good mechanical properties at room and elevated temperatures is a challenge that metallurgy and materials science communities are facing for many years, and no “dream material” has been developed so far. The primary goal of this study was to fabricate, characterize, and to carry out tensile tests on Al-based composite materials strengthened with commercially-available BN nanoparticles (BNNPs). The composites were fabricated by spark plasma sintering (SPS) technique. The structures of powder mixtures and composite materials, as well as their fracture surfaces, were studied by scanning and transmission electron microscopy. The influence of BNNPs content (0.5, 1.5, 3, 4.5, 6, and 7.5 wt%) and holding times (5, 60, and 300 min) at 600 °C during SPS on the tensile strength was investigated. A maximum increase in strength was observed for Al-based composites with 4.5 wt% of BNNPs. The sample demonstrated a 50% increase in tensile strength compared with pristine Al. Although the tensile tests performed at 300 °C revealed that the tensile strength became 20% lower than the strength at room temperature, it was, however, still 75% higher compared with that of the pure Al at 300 °C. In addition, at 300 °C the Al–BNNPs composites demonstrated a much higher value of yield stress, about 115 MPa, which is 190% higher than that of pure Al at the same temperature. The damping properties of Al–BNNPs composites were evaluated by temperature dependent internal friction (TDIF) measurements. The obtained results are discussed based on structural analysis and the TDIF data.

  4. Fabrication and characterization of aerosol-jet printed strain sensors for multifunctional composite structures

    Science.gov (United States)

    Zhao, Da; Liu, Tao; Zhang, Mei; Liang, Richard; Wang, Ben

    2012-11-01

    Traditional multifunctional composite structures are produced by embedding parasitic parts, such as foil sensors, optical fibers and bulky connectors. As a result, the mechanical properties of the composites, especially the interlaminar shear strength (ILSS), could be largely undermined. In the present study, we demonstrated an innovative aerosol-jet printing technology for printing electronics inside composite structures without degrading the mechanical properties. Using the maskless fine feature deposition (below 10 μm) characteristics of this printing technology and a pre-cure protocol, strain sensors were successfully printed onto carbon fiber prepregs to enable fabricating composites with intrinsic sensing capabilities. The degree of pre-cure of the carbon fiber prepreg on which strain sensors were printed was demonstrated to be critical. Without pre-curing, the printed strain sensors were unable to remain intact due to the resin flow during curing. The resin flow-induced sensor deformation can be overcome by introducing 10% degree of cure of the prepreg. In this condition, the fabricated composites with printed strain sensors showed almost no mechanical degradation (short beam shearing ILSS) as compared to the control samples. Also, the failure modes examined by optical microscopy showed no difference. The resistance change of the printed strain sensors in the composite structures were measured under a cyclic loading and proved to be a reliable mean strain gauge factor of 2.2 ± 0.06, which is comparable to commercial foil metal strain gauge.

  5. Low Cost Fabrication of Silicon Carbide Based Ceramics and Fiber Reinforced Composites

    Science.gov (United States)

    Singh, M.; Levine, S. R.

    1995-01-01

    A low cost processing technique called reaction forming for the fabrication of near-net and complex shaped components of silicon carbide based ceramics and composites is presented. This process consists of the production of a microporous carbon preform and subsequent infiltration with liquid silicon or silicon-refractory metal alloys. The microporous preforms are made by the pyrolysis of a polymerized resin mixture with very good control of pore volume and pore size thereby yielding materials with tailorable microstructure and composition. Mechanical properties (elastic modulus, flexural strength, and fracture toughness) of reaction-formed silicon carbide ceramics are presented. This processing approach is suitable for various kinds of reinforcements such as whiskers, particulates, fibers (tows, weaves, and filaments), and 3-D architectures. This approach has also been used to fabricate continuous silicon carbide fiber reinforced ceramic composites (CFCC's) with silicon carbide based matrices. Strong and tough composites with tailorable matrix microstructure and composition have been obtained. Microstructure and thermomechanical properties of a silicon carbide (SCS-6) fiber reinforced reaction-formed silicon carbide matrix composites are discussed.

  6. Fabrication of Aligned-Carbon-Nanotube-Composite Paper with High and Anisotropic Conductivity

    Directory of Open Access Journals (Sweden)

    Yuki Fujitsuka

    2012-01-01

    Full Text Available A functional carbon-nanotube (CNT-composite paper is described in which the CNTs are aligned. This “aligned-CNT composite paper” is a flexible composite material that has CNT functionality (e.g., electrical conductivity despite being a paper. An advanced fabrication method was developed to overcome the problem of previous CNT-composite papers, that is, reduced conductivity due to random CNT alignment. Aligning the CNTs by using an alternating current (AC field was hypothesized to increase the electrical conductivity and give the paper an anisotropic characteristic. Experimental results showed that a nonionic surfactant was not suitable as a CNT dispersant for fabricating aligned-CNT composite paper and that catechin with its six-membered rings and hydrophilic groups was suitable. Observation by scanning electron microscopy of samples prepared using catechin showed that the CNTs were aligned in the direction of the AC field on the paper fibers. Measurement of the electric conductivity showed that the surface resistance was different between the direction of the aligned CNTs (high conductivity and that of verticality (low. The conductivity of the aligned-CNT-composite paper samples was higher than that of nonaligned samples. This unique and functional paper, which has high and anisotropic conductivity, is applicable to a conductive material to control the direction of current.

  7. Rate Dependent Multicontinuum Progressive Failure Analysis of Woven Fabric Composite Structures under Dynamic Impact

    Directory of Open Access Journals (Sweden)

    James Lua

    2004-01-01

    Full Text Available Marine composite materials typically exhibit significant rate dependent response characteristics when subjected to extreme dynamic loading conditions. In this work, a strain-rate dependent continuum damage model is incorporated with multicontinuum technology (MCT to predict damage and failure progression for composite material structures. MCT treats the constituents of a woven fabric composite as separate but linked continua, thereby allowing a designer to extract constituent stress/strain information in a structural analysis. The MCT algorithm and material damage model are numerically implemented with the explicit finite element code LS-DYNA3D via a user-defined material model (umat. The effects of the strain-rate hardening model are demonstrated through both simple single element analyses for woven fabric composites and also structural level impact simulations of a composite panel subjected to various impact conditions. Progressive damage at the constituent level is monitored throughout the loading. The results qualitatively illustrate the value of rate dependent material models for marine composite materials under extreme dynamic loading conditions.

  8. Study on titanium-magnesium composites with bicontinuous structure fabricated by powder metallurgy and ultrasonic infiltration.

    Science.gov (United States)

    Jiang, S; Huang, L J; An, Q; Geng, L; Wang, X J; Wang, S

    2018-02-14

    Titanium-magnesium (Ti-Mg) composites with bicontinuous structure have been successfully fabricated by powder metallurgy and ultrasonic infiltration for biomaterial potential. In the composites, Ti phase is distributed continuously by sintering necks, while Mg phase is also continuous, distributing at the interconnected pores surrounding the Ti phase. The results showed that the fabricated Ti-Mg composites exhibited low modulus and high strength, which are very suitable for load bearing biomedical materials. The composites with 100 µm and 230 µm particle sizes exhibited Young's modulus of 37.6 GPa and 23.4 GPa, 500.7 MPa and 340 MPa of compressive strength and 631.5 MPa and 375.2 MPa of bending strength, respectively. Moreover, both of the modulus and strength of the composites increase with decreasing of Ti particle sizes. In vitro study has been done for the preliminary evaluation of the Ti-Mg composites. Copyright © 2018 Elsevier Ltd. All rights reserved.

  9. Modeling of an improved chemical vapor infiltration process for ceramic composites fabrication

    International Nuclear Information System (INIS)

    Tai, N.H.; Chou, T.W.

    1990-01-01

    A quasi-steady-state approach is applied to model the pressure-driven, temperature-gradient chemical vapor infiltration (improved CVI process) for ceramic matrix composites fabrication. The deposited matrix in this study is SiC which is converted from the thermal decomposition of methyltrichlorosilane gas under excess hydrogen. A three-dimensional unit cell is adopted to simulate the spatial arrangements of reinforcements in discontinuous fiber mats and three-dimensionally woven fabrics. The objectives of this paper are to predict the temperature and density distributions in a fibrous preform during processing, the advancement of the solidified front, the total fabrication period, and the vapor inlet pressure variation for maintaining a constant flow rate

  10. Submicron-sized actuators based on enhanced shape memory composite material fabricated by FIB-CVD

    International Nuclear Information System (INIS)

    Zakharov, Dmitry; Lebedev, Gor; Irzhak, Artemy; Podgorny, Dmitry; Tabachkova, Natalia; Afonina, Veronika; Mashirov, Alexey; Kalashnikov, Vladimir; Koledov, Viktor; Shavrov, Vladimir; Shelyakov, Alexander

    2012-01-01

    An enhanced scheme for a functional bilayered composite material with shape memory effect has been successfully applied on the microscale to fabricate a thermally controlled microactuator. Fabrication of cantilever-type microactuators from melt spun ribbon of TiNiCu shape memory alloy included electro-chemical polishing followed by focused ion beam milling and ion-assisted chemical vapor deposition of Pt elastic layer. The smallest working microactuator had a volume of 0.9 µm 3 . The structure and thermal stability of the Pt layer have been investigated. The fabricated actuator has been proposed for use as micromechanical nanotweezers for manipulation of submicron- and nano-sized objects. Manipulation of a carbon nanotube bunch has been demonstrated. (fast track communication)

  11. High-Strength Composite Fabric Tested at Structural Benchmark Test Facility

    Science.gov (United States)

    Krause, David L.

    2002-01-01

    Large sheets of ultrahigh strength fabric were put to the test at NASA Glenn Research Center's Structural Benchmark Test Facility. The material was stretched like a snare drum head until the last ounce of strength was reached, when it burst with a cacophonous release of tension. Along the way, the 3-ft square samples were also pulled, warped, tweaked, pinched, and yanked to predict the material's physical reactions to the many loads that it will experience during its proposed use. The material tested was a unique multi-ply composite fabric, reinforced with fibers that had a tensile strength eight times that of common carbon steel. The fiber plies were oriented at 0 and 90 to provide great membrane stiffness, as well as oriented at 45 to provide an unusually high resistance to shear distortion. The fabric's heritage is in astronaut space suits and other NASA programs.

  12. High energy ballistic and fracture comparison between multilayered armor systems using non-woven curaua fabric composites and aramid laminates

    Directory of Open Access Journals (Sweden)

    Fábio de Oliveira Braga

    2017-10-01

    Full Text Available For personal protection against high kinetic energy projectiles, multilayered armor systems (MAS are usually the best option. They combine synergistically the properties of different materials such as ceramics, composites and metals. In the present work, ballistic tests were performed to evaluate multilayered armor systems (MAS using curaua non-woven fabric epoxy composites as second layer. A comparison to a MAS using aramid (Kevlar™ fabric laminates was made. The results showed that the curaua non-woven fabric composites are suitable to the high ballistic applications, and are promising substitutes for aramid fabric laminates. Keywords: Composite, Natural fiber, Curaua fiber, Non-woven fabric, Aramid laminate, Ballistic test

  13. A Comparative Application for Evaluating Composite Fabrics Used in Electromagnetic Shielding

    Directory of Open Access Journals (Sweden)

    F. G. Kizilcay Abdulla

    2017-12-01

    Full Text Available Composite fabrics containing metal filaments are used widely for preventing electromagnetic radiation. Many experiments involving them are carried out continuously. Results are simulated in order to analyze their performance. Coding in Matlab is a popular method to compare the electromagnetic shielding properties of composite fabrics but for different options Matlab codes must be edited each time. Scientists who are not experts in coding have difficulties on editing such codes. To overcome this, an application written in C# in Visual Studio with .Net platform was developed. This application is integrated with Bunifu, which allows the application to be well designed. The proposed interface is user friendly and lets the user choose the available fabric with its stitch length from panel section. By setting options one can get the electromagnetic parameters such as scattering (S parameters, reflection, transmission and absorption coefficients and total shielding effectiveness (SE values with one click. As the application is integrated with Matlab codes, output is given as a Matlab graph with desired options. In this way the distinctions between the chosen fabrics can be analyzed easily.

  14. Fabrication of Composite Filaments with High Dielectric Permittivity for Fused Deposition 3D Printing.

    Science.gov (United States)

    Wu, Yingwei; Isakov, Dmitry; Grant, Patrick S

    2017-10-23

    Additive manufacturing of complex structures with spatially varying electromagnetic properties can enable new applications in high-technology sectors such as communications and sensors. This work presents the fabrication method as well as microstructural and dielectric characterization of bespoke composite filaments for fused deposition modeling (FDM) 3D printing of microwave devices with a high relative dielectric permittivity ϵ = 11 in the GHz frequency range. The filament is composed of 32 vol % of ferroelectric barium titanate (BaTiO 3 ) micro-particles in a polymeric acrylonitrile butadiene styrene (ABS) matrix. An ionic organic ester surfactant was added during formulation to enhance the compatibility between the polymer and the BaTiO 3 . To promote reproducible and robust printability of the fabricated filament, and to promote plasticity, dibutyl phthalate was additionally used. The combined effect of 1 wt % surfactant and 5 wt % plasticizer resulted in a uniform, many hundreds of meters, continuous filament of commercial quality capable of many hours of uninterrupted 3D printing. We demonstrate the feasibility of using the high dielectric constant filament for 3D printing through the fabrication of a range of optical devices. The approach herein may be used as a guide for the successful fabrication of many types of composite filament with varying functions for a broad range of applications.

  15. Fabrication of Composite Filaments with High Dielectric Permittivity for Fused Deposition 3D Printing

    Directory of Open Access Journals (Sweden)

    Yingwei Wu

    2017-10-01

    Full Text Available Additive manufacturing of complex structures with spatially varying electromagnetic properties can enable new applications in high-technology sectors such as communications and sensors. This work presents the fabrication method as well as microstructural and dielectric characterization of bespoke composite filaments for fused deposition modeling (FDM 3D printing of microwave devices with a high relative dielectric permittivity ϵ = 11 in the GHz frequency range. The filament is composed of 32 vol % of ferroelectric barium titanate (BaTiO 3 micro-particles in a polymeric acrylonitrile butadiene styrene (ABS matrix. An ionic organic ester surfactant was added during formulation to enhance the compatibility between the polymer and the BaTiO 3 . To promote reproducible and robust printability of the fabricated filament, and to promote plasticity, dibutyl phthalate was additionally used. The combined effect of 1 wt % surfactant and 5 wt % plasticizer resulted in a uniform, many hundreds of meters, continuous filament of commercial quality capable of many hours of uninterrupted 3D printing. We demonstrate the feasibility of using the high dielectric constant filament for 3D printing through the fabrication of a range of optical devices. The approach herein may be used as a guide for the successful fabrication of many types of composite filament with varying functions for a broad range of applications.

  16. Fabrication of Composite Filaments with High Dielectric Permittivity for Fused Deposition 3D Printing

    Science.gov (United States)

    Wu, Yingwei

    2017-01-01

    Additive manufacturing of complex structures with spatially varying electromagnetic properties can enable new applications in high-technology sectors such as communications and sensors. This work presents the fabrication method as well as microstructural and dielectric characterization of bespoke composite filaments for fused deposition modeling (FDM) 3D printing of microwave devices with a high relative dielectric permittivity ϵ=11 in the GHz frequency range. The filament is composed of 32 vol % of ferroelectric barium titanate (BaTiO3) micro-particles in a polymeric acrylonitrile butadiene styrene (ABS) matrix. An ionic organic ester surfactant was added during formulation to enhance the compatibility between the polymer and the BaTiO3. To promote reproducible and robust printability of the fabricated filament, and to promote plasticity, dibutyl phthalate was additionally used. The combined effect of 1 wt % surfactant and 5 wt % plasticizer resulted in a uniform, many hundreds of meters, continuous filament of commercial quality capable of many hours of uninterrupted 3D printing. We demonstrate the feasibility of using the high dielectric constant filament for 3D printing through the fabrication of a range of optical devices. The approach herein may be used as a guide for the successful fabrication of many types of composite filament with varying functions for a broad range of applications. PMID:29065537

  17. A novel method of fabricating carbon nanotubes-polydimethylsiloxane composite electrodes for electrocardiography.

    Science.gov (United States)

    Liu, Benyan; Chen, Yingmin; Luo, Zhangyuan; Zhang, Wenzan; Tu, Quan; Jin, Xun

    2015-01-01

    Polymer-based flexible electrodes are receiving much attention in medical applications due to their good wearing comfort. The current fabrication methods of such electrodes are not widely applied. In this study, polydimethylsiloxane (PDMS) and conductive additives of carbon nanotubes (CNTs) were employed to fabricate composite electrodes for electrocardiography (ECG). A three-step dispersion process consisting of ultrasonication, stirring, and in situ polymerization was developed to yield homogenous CNTs-PDMS mixtures. The CNTs-PDMS mixtures were used to fabricate CNTs-PDMS composite electrodes by replica technology. The influence of ultrasonication time and CNT concentration on polymer electrode performance was evaluated by impedance and ECG measurements. The signal amplitude of the electrodes prepared using an ultrasonication time of 12 h and CNT content of 5 wt% was comparable to that of commercial Ag/AgCl electrodes. The polymer electrodes were easily fabricated by conventional manufacturing techniques, indicating a potential advantage of reduced cost for mass production.

  18. Fabrication and Application of Iron(III-Oxide Nanoparticle/Polydimethylsiloxane Composite Cone in Microfluidic Channels

    Directory of Open Access Journals (Sweden)

    Cheng-Chun Huang

    2012-01-01

    Full Text Available This paper presented the fabrication and applications of an iron(III-oxide nanoparticle/polydimethylsiloxane (PDMS cone as a component integrated in lab on a chip. The two main functions of this component were to capture magnetic microbeads in the microfluid and to mix two laminar fluids by generating disturbance. The iron(III-oxide nanoparticle/PDMS cone was fabricated by automatic dispensing and magnetic shaping. Three consecutive cones of 300 μm in height were asymmetrically placed along a microchannel of 2 mm in width and 1.1 mm in height. Flow passing the cones was effectively redistributed for Renolds number lower than . Streptavidin-coated magnetic microbeads which were bound with biotin were successfully captured by the composite cones as inspected under fluorescence microscope. The process parameters for fabricating the composite cones were investigated. The fabricated cone in the microchannel could be applied in lab on a chip for bioassay in the future.

  19. Cotton fabric with plasma pretreatment and ZnO/Carboxymethyl chitosan composite finishing for durable UV resistance and antibacterial property.

    Science.gov (United States)

    Wang, Chunxia; Lv, Jingchun; Ren, Yu; Zhou, Qingqing; Chen, Jiayi; Zhi, Tian; Lu, Zhenqian; Gao, Dawei; Ma, Zhipeng; Jin, Limin

    2016-03-15

    ZnO/carboxymethyl chitosan (ZnO/CMCS) composite was prepared and confirmed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Ultraviolet-visible (UV-vis) spectroscopy, Scanning electron microscope (SEM), Transmission electron microscope (TEM). The combination of plasma pretreatment and ZnO/CMCS composite finishing was applied to provide durable UV resistance and antibacterial activity for cotton fabric. Cotton fabric was pretreated by cold oxygen plasma and the ZnO/CMCS composite finishing was carried out by pad-dry-cure. Cotton fabric was characterized by SEM, FTIR, UV resistance, antibacterial activity and Thermogravimetry (TG). SEM and FTIR analysis demonstrated the presence of ZnO/CMCS composite on cotton fabric and the increasing loading efficiency of ZnO/CMCS composite owing to plasma treatment. UV resistance and antibacterial activity of the finished cotton fabric were greatly improved, which increased with the increasing concentration of ZnO/CMCS composite. TG analysis indicated that the combined finishing of cotton fabric with plasma pretreatment and ZnO/CMCS composite could improve its thermal property. The finished cotton fabric exhibited an excellent laundering durability in UV resistance and antibacterial activity. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Apparatus, system, and method for providing fabric-elastomer composites as pneumatic actuators

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, Ramses V.; Whitesides, George M.

    2017-10-25

    Soft pneumatic actuators based on composites consisting of elastomers with embedded sheet or fiber structures (e.g., paper or fabric) that are flexible but not extensible are described. On pneumatic inflation, these actuators move anisotropically, based on the motions accessible by their composite structures. They are inexpensive, simple to fabricate, light in weight, and easy to actuate. This class of structure is versatile: the same principles of design lead to actuators that respond to pressurization with a wide range of motions (bending, extension, contraction, twisting, and others). Paper, when used to introduce anisotropy into elastomers, can be readily folded into three-dimensional structures following the principles of origami; these folded structures increase the stiffness and anisotropy of the elastomeric actuators, while keeping them light in weight.

  1. Preparation and properties of copper/polyaniline/polyester composite electromagnetic shielding fabric

    Directory of Open Access Journals (Sweden)

    Jing YU

    2016-04-01

    Full Text Available Conductive polyaniline and polyester composite fabric(PANI/PET is prepared by in-situ polymerization, and after it is activated by hyperbranched polyamidomine/Ag+, Cu is uniformly deposited on its surface by electroless copper plating, finally Cu/PANI/PET composite fabric is obtained. Scanning electron microscope, X-ray diffraction and electromagnetic shielding effectiveness are used to analyze the samples. The results show that using PANI as the middle layer can reduce the average grain size apparently and improve the thermal stability and the friction resistance, and the electromagnetic shielding effectiveness of Cu/PANI/PET can reach 130 dB in the frequency range of 300 kHz~3 GHz.

  2. Fabrication and characterization of nanofiber-nanoparticle-composites with phase change materials by electrospinning

    International Nuclear Information System (INIS)

    Babapoor, Aziz; Karimi, Gholamreza; Khorram, Mohammad

    2016-01-01

    Highlights: • Form-stable nanofibers with phase change material are produced by electrospinning. • PA6 and PEG are used as the supporting matrix and phase change material. • Various nanoparticles are used to enhance thermal properties of the fibers. • The nanofiber-nanoparticle composites exhibited desirable thermal stability. • Al 2 O 3 nanoparticles improved thermal conductivity of the composites considerably. - Graphical Abstract: Display Omitted - Abstract: Thermal energy storage has been recognized as one of the most important technologies for the utilization of renewable energy sources and conserving energy. In this investigation, through combination of polyethylene glycol (PEG) as a phase change material (PCM), polyamid6 (PA6) and various nanoparticles (SiO 2 , Al 2 O 3 , Fe 2 O 3 and ZnO) as supporting materials, novel form-stable PCMs-based composites were fabricated by single nozzle electrospinning. The structure, morphology and thermal properties of the prepared nanofiber-nanocomposite-enhanced phase change materials (NEPCMs) were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy and differential scanning calorimeter, respectively. Based on the results, nanocomposites-nanofibers were successfully fabricated with high thermal stability and reliability. It is observed that in all composites, the fiber diameter is decreased by increasing the nanoparticles loading. The lowest average diameter obtained was for Fe 2 O 3 composite. Al 2 O 3 composite showed the maximum thermal conductivity enhancement. This study suggests that the fabricated nanocomposite-PCMs offer proper phase transition temperature range and high heat enthalpy values and hence, have potential for thermal energy storage applications.

  3. Fabrication of Porous Materials from Natural/Synthetic Biopolymers and Their Composites

    Directory of Open Access Journals (Sweden)

    Udeni Gunathilake T.M. Sampath

    2016-12-01

    Full Text Available Biopolymers and their applications have been widely studied in recent years. Replacing the oil based polymer materials with biopolymers in a sustainable manner might give not only a competitive advantage but, in addition, they possess unique properties which cannot be emulated by conventional polymers. This review covers the fabrication of porous materials from natural biopolymers (cellulose, chitosan, collagen, synthetic biopolymers (poly(lactic acid, poly(lactic-co-glycolic acid and their composite materials. Properties of biopolymers strongly depend on the polymer structure and are of great importance when fabricating the polymer into intended applications. Biopolymers find a large spectrum of application in the medical field. Other fields such as packaging, technical, environmental, agricultural and food are also gaining importance. The introduction of porosity into a biomaterial broadens the scope of applications. There are many techniques used to fabricate porous polymers. Fabrication methods, including the basic and conventional techniques to the more recent ones, are reviewed. Advantages and limitations of each method are discussed in detail. Special emphasis is placed on the pore characteristics of biomaterials used for various applications. This review can aid in furthering our understanding of the fabrication methods and about controlling the porosity and microarchitecture of porous biopolymer materials.

  4. Fabrication and Water Treatment Application of Carbon Nanotubes (CNTs)-Based Composite Membranes: A Review

    OpenAIRE

    Ma, Lining; Dong, Xinfa; Chen, Mingliang; Zhu, Li; Wang, Chaoxian; Yang, Fenglin; Dong, Yingchao

    2017-01-01

    Membrane separation technology is widely explored for various applications, such as water desalination and wastewater treatment, which can alleviate the global issue of fresh water scarcity. Specifically, carbon nanotubes (CNTs)-based composite membranes are increasingly of interest due to the combined merits of CNTs and membrane separation, offering enhanced membrane properties. This article first briefly discusses fabrication and growth mechanisms, characterization and functionalization tec...

  5. A new method to fabricate Fe-TiC composite using conventional sintering and steam hammer

    OpenAIRE

    LAHOUEL, Ali; BOUDEBANE, Saïd; IOST, Alain; MONTAGNE, Alex

    2017-01-01

    International audience; The aim of this research paper is to fabricate a Fe-TiC composite by a novel and simple manufacturing method. The latter is based on two cumulative processes; a conventional sintering (transient liquid phase sintering) and a hot forging with steam hammer respectively. The blinder phase of the studied simples is varied from carbon steel to high alloy steel using alloying additive powders. The obtained outcomes showed that after the sintering process, the relative densit...

  6. Exploring mechanical property balance in tufted carbon fabric/epoxy composites.

    OpenAIRE

    Dell'Anno, Giuseppe; Cartié, Denis D. R.; Partridge, Ivana K.; Rezai, Amir

    2007-01-01

    The paper details the manufacturing processes involved in the preparation of through-the-thickness reinforced composites via the ‘dry preform–tufting–liquid resin injection’ route. Samples for mechanical testing were prepared by tufting a 5 harness satin weave carbon fabric in a 3 mm × 3 mm square pitch configuration with a commercial glass or carbon tufting thread, infusing the reinforced preforms with liquid epoxy resin and curing them under moderate pressure. The glass th...

  7. Facile fabrication of a lotus-effect composite coating via wrapping silica with polyurethane

    Energy Technology Data Exchange (ETDEWEB)

    Su Changhong, E-mail: suchhnju@yahoo.com.cn [Department of Material Science, School of Material Science and Engineering, Shandong University of Technology, Zhangzou Road 22, Zibo 255049 (China)

    2010-01-15

    A lotus-effect coating was fabricated by wrapping micro-silica and nano-silica with polyurethane (PU) and subsequent spraying. The coating shows the similar self-cleaning property as lotus leaves: the contact angle is as large as 168 deg. and the sliding angle is as low as 0.5 deg. Surface morphology of the coating was studied with scanning electron microscopy and atomic force microscopy. The composite coating shows the similar structure as lotus leaves.

  8. Damage and fracture in fabric-reinforced composites under quasi-static and dynamic bending

    International Nuclear Information System (INIS)

    Ullah, H; Harland, A R; Silberschmidt, V V

    2013-01-01

    Fabric-reinforced polymer composites used in sports products can be exposed to different in-service conditions such as large deformations caused by quasi-static and dynamic loading. Composite materials subjected to such bending loads can demonstrate various damage modes – matrix cracking, delamination and, ultimately, fabric fracture. Damage evolution in composites affects both their in-service properties and performance that can deteriorate with time. Such behaviour needs adequate means of analysis and investigation, the main approaches being experimental characterisation and non-destructive examination of internal damage in composite laminates. This research deals with a deformation behaviour and damage in carbon fabric-reinforced polymer (CFRP) laminates caused by quasi-static and dynamic bending. Experimental tests were carried out to characterise the behaviour of a CFRP material under large-deflection bending, first in quasi-static and then in dynamic conditions. Izod-type impact bending tests were performed on un-notched specimens of CFRP using a Resil impactor to assess the transient response and energy absorbing capability of the material. X-ray micro computed tomography (micro-CT) was used to analyse various damage modes in the tested specimens. X-ray tomographs revealed that through-thickness matrix cracking, inter-ply and intra-ply delamination such as tow debonding, and fabric fracture were the prominent damage modes both in quasi-static and dynamic test specimens. However, the inter-ply damage was localised at impact location in dynamically tested specimens, whereas in the quasi-static specimens, it spread almost over the entire interface

  9. Damage and fracture in fabric-reinforced composites under quasi-static and dynamic bending

    Science.gov (United States)

    Ullah, H.; Harland, A. R.; Silberschmidt, V. V.

    2013-07-01

    Fabric-reinforced polymer composites used in sports products can be exposed to different in-service conditions such as large deformations caused by quasi-static and dynamic loading. Composite materials subjected to such bending loads can demonstrate various damage modes - matrix cracking, delamination and, ultimately, fabric fracture. Damage evolution in composites affects both their in-service properties and performance that can deteriorate with time. Such behaviour needs adequate means of analysis and investigation, the main approaches being experimental characterisation and non-destructive examination of internal damage in composite laminates. This research deals with a deformation behaviour and damage in carbon fabric-reinforced polymer (CFRP) laminates caused by quasi-static and dynamic bending. Experimental tests were carried out to characterise the behaviour of a CFRP material under large-deflection bending, first in quasi-static and then in dynamic conditions. Izod-type impact bending tests were performed on un-notched specimens of CFRP using a Resil impactor to assess the transient response and energy absorbing capability of the material. X-ray micro computed tomography (micro-CT) was used to analyse various damage modes in the tested specimens. X-ray tomographs revealed that through-thickness matrix cracking, inter-ply and intra-ply delamination such as tow debonding, and fabric fracture were the prominent damage modes both in quasi-static and dynamic test specimens. However, the inter-ply damage was localised at impact location in dynamically tested specimens, whereas in the quasi-static specimens, it spread almost over the entire interface.

  10. Size and composition-controlled fabrication of VO2 nanocrystals by terminated cluster growth

    Energy Technology Data Exchange (ETDEWEB)

    Anders, Andre; Slack, Jonathan

    2013-05-14

    A physical vapor deposition-based route for the fabrication of VO2 nanoparticles is demonstrated, consisting of reactive sputtering and vapor condensation at elevated pressures. The oxidation of vanadium atoms is an efficient heterogeneous nucleation method, leading to high nanoparticle throughtput. Fine control of the nanoparticle size and composition is obtained. Post growth annealing leads to crystalline VO2 nanoparticles with optimum thermocromic and plasmonic properties.

  11. Cyrogenic and radiation resistant properties of three dimensional fabric reinforced composite materials

    International Nuclear Information System (INIS)

    Yasuda, J.; Hirodawa, T.; Uemura, T.; Iwasaki, Y.; Nishijima, S.; Okada, T.; Okuyama, H.; Wang, Y.A.

    1988-01-01

    The insulating and/or structural materials for the fusion superconducting magnets are used under such strict environments as the cryogenic temperatures, high stresses and radiation environments. It is recognized that the usual laminated composite materials reinforced by glass clothes (2D-GFRP) are difficult to be used in such strict conditions. The three dimensional glass fabric reinforced composite materials (3D-GFRP) have high interlaminar shear strength due to the fibers in thickness direction. The cryogenic and radiation resistance properties of 3D-GFRP had been measured and the results compared with those of the 2D-GFRP

  12. Fabrication of high thermal conductivity arrays of carbon nanotubes and their composites

    Science.gov (United States)

    Geohegan, David B [Knoxville, TN; Ivanov, Ilya N [Knoxville, TN; Puretzky, Alexander A [Knoxville, TN

    2010-07-27

    Methods and apparatus are described for fabrication of high thermal conductivity arrays of carbon nanotubes and their composites. A composition includes a vertically aligned nanotube array including a plurality of nanotubes characterized by a property across substantially all of the vertically aligned nanotube array. A method includes depositing a vertically aligned nanotube array that includes a plurality of nanotubes; and controlling a deposition rate of the vertically aligned nanotubes array as a function of an in situ monitored property of the plurality of nanotubes.

  13. Fabrication of superhydrophobic sol-gel composite films using hydrophobically modified colloidal zinc hydroxide.

    Science.gov (United States)

    Lakshmi, R V; Basu, Bharathibai J

    2009-11-15

    A superhydrophobic sol-gel composite film was fabricated by incorporating hydrophobically modified colloidal zinc hydroxide (CZH) in sol-gel matrix. CZH was prepared by controlled precipitation and modified by treatment with stearic acid. The concentration of stearic acid and stirring time were optimized to obtain modified CZH with very high water contact angle (WCA) of 165 degrees and sliding angle (SA)superhydrophobic surfaces. FTIR spectrum also confirmed the presence of zinc stearate in the composite film. The method is simple and cost-effective and does not involve any expensive chemicals or equipments.

  14. Fabrication of graphene/polydopamine/copper foam composite material and its application as supercapacitor electrode

    Science.gov (United States)

    Zheng, Y.; Lu, S. X.; Xu, W. G.; He, G.; Cheng, Y. Y.; Xiao, F. Y.; Zhang, Y.

    2018-01-01

    In this work, a composite electrode was fabricated by chemical deposition of polydopamine (PDA) and graphene oxide (GO) on the copper foam (CF) surface, followed by annealing treatment. Owing to the cohesive effect of the PDA middle film, GO was coated on CF surface successfully, and then reduced simultaneously while annealing. The resulted rGO/PDA/CF composite electrode was directly used as a supercapacitor electrode and exhibited excellent electrochemical performance, with a high specific capacitance of 1250 F g-1 at 2 A g-1 and favorable cycle stability.

  15. Osteoconductive and degradable electrospun nonwoven poly(epsilon-caprolactone)/CaO-SiO2 gel composite fabric.

    Science.gov (United States)

    Seol, Yang-Jo; Kim, Kyoung-Hwa; Kim, In Ae; Rhee, Sang-Hoon

    2010-08-01

    A nonwoven ceramic/polymer composite fabric composed of randomly mixed bioactive and fast degradable CaO-SiO(2) gel fibers and biodegradable poly(epsilon-caprolactone) (PCL) fibers is prepared with a simultaneous electrospinning method for potential use as bone grafting materials. A 17% PCL solution is prepared using 1,1,3,3-hexafluoro-2-propanol as the solvent, whereas the CaO-SiO(2) gel solution is prepared via a condensation reaction following the hydrolysis of tetraethyl orthosilicate. PCL and CaO-SiO(2) gel solutions are spun simultaneously with two separate nozzles. As controls, pure PCL and CaO-SiO(2) gel nonwoven fabrics are also made by the same methods. The three nonwoven fabrics were exposed to simulated body fluid for 1 week and resulted in the deposition of a layer of apatite crystals on the surfaces of both the CaO-SiO(2) gel and PCL/CaO-SiO(2) gel composite fabrics, but not on the PCL fabric. A tensile strength test showed that the fracture behavior of the CaO-SiO(2) gel fabric was brittle, that of the PCL fabric was ductile-tough, and that of the PCL/CaO-SiO(2) gel composite fabric was intermediate between that of the CaO-SiO(2) gel and PCL fabrics. Our in vivo tests showed that the CaO-SiO(2) gel and PCL/CaO-SiO(2) gel composite fabrics had good osteoconductivity and fast degradation rates in calvarial defects of New Zealand white rabbits within 4 weeks, in contrast to the pure PCL fabric. Together, these results suggest that the composite fabric composed of PCL and CaO-SiO(2) gel fibers must have a great potential for use in applications such as bone grafting because of its good osteoconductivity and adequate mechanical properties. (c) 2010 Wiley Periodicals, Inc.

  16. A novel method for Al/SiC composite fabrication. Lost foam casting

    Energy Technology Data Exchange (ETDEWEB)

    Guler, Kerem A.; Kisasoz, Alptekin; Karaaslan, Ahmet [Yildiz Technical Univ., Istanbul (Turkey). Dept. of Metallurgy and Materials Engineering

    2011-03-15

    In this paper, an innovative manufacturing approach to cast metal-matrix composite is proposed. Aluminum matrix composite production by lost foam casting has been investigated. In order to produce metal-matrix composite by lost foam casting, expanded polystyrene boards were designed as sandwich shaped and three layered. SiC particulates with 60 {mu}m average grain size were settled between the board layers, while A6063 and A413 aluminum alloys were used as matrix materials. The effect of the matrix materials on the mechanical properties of the composite specimens was investigated and fabricated specimens were characterized using image analysis, hardness tests, scanning electron microscope and X-ray diffraction analysis. The results show that in the lost foam casting method, the hardness of the A6063 and the A413 materials specimens increases with SiC reinforcement up to 70% and 80%, respectively. (orig.)

  17. Tungsten Oxide and Polyaniline Composite Fabricated by Surfactant-Templated Electrodeposition and Its Use in Supercapacitors

    Directory of Open Access Journals (Sweden)

    Benxue Zou

    2014-01-01

    Full Text Available Composite nanostructures of tungsten oxide and polyaniline (PANI were fabricated on carbon electrode by electrocodeposition using sodium dodecylbenzene sulfonate (SDBS as the template. The morphology of the composite can be controlled by changing SDBS surfactant and aniline monomer concentrations in solution. With increasing concentration of aniline in surfactant solution, the morphological change from nanoparticles to nanofibers was observed. The nanostructured WO3/PANI composite exhibited enhanced capacitive charge storage with the specific capacitance of 201 F g−1 at 1.28 mA cm−2 in large potential window of -0.5~ 0.65 V versus SCE compared to the bulk composite film. The capacitance retained about 78% when the sweeping potential rate increased from 10 to 150 mV/s.

  18. PEDOT–CNT Composite Microelectrodes for Recording and Electrostimulation Applications: Fabrication, Morphology, and Electrical Properties

    Science.gov (United States)

    Gerwig, Ramona; Fuchsberger, Kai; Schroeppel, Birgit; Link, Gordon Steve; Heusel, Gerhard; Kraushaar, Udo; Schuhmann, Wolfgang; Stett, Alfred; Stelzle, Martin

    2012-01-01

    Composites of carbon nanotubes and poly(3,4-ethylenedioxythiophene, PEDOT) and layers of PEDOT are deposited onto microelectrodes by electropolymerization of ethylenedioxythiophene in the presence of a suspension of carbon nanotubes and polystyrene sulfonate. Analysis by FIB and SEM demonstrates that CNT–PEDOT composites exhibit a porous morphology whereas PEDOT layers are more compact. Accordingly, capacitance and charge injection capacity of the composite material exceed those of pure PEDOT layers. In vitro cell culture experiments reveal excellent biocompatibility and adhesion of both PEDOT and PEDOT–CNT electrodes. Signals recorded from heart muscle cells demonstrate the high S/N ratio achievable with these electrodes. Long-term pulsing experiments confirm stability of charge injection capacity. In conclusion, a robust fabrication procedure for composite PEDOT–CNT electrodes is demonstrated and results show that these electrodes are well suited for stimulation and recording in cardiac and neurophysiological research. PMID:22586394

  19. PEDOT-CNT composite microelectrodes for recording and electrostimulation applications: fabrication, morphology and electrical properties

    Directory of Open Access Journals (Sweden)

    Ramona eGerwig

    2012-05-01

    Full Text Available Composites of carbon nanotubes and poly(3,4-ethylenedioxythiophene (PEDOT and layers of PEDOT are deposited onto microelectrodes by electropolymerization of ethylenedioxythiophene in the presence of a suspension of carbon nanotubes and polystyrenesulfonate. Analysis by FIB and SEM demonstrate that CNT-PEDOT composites exhibit a porous morphology whereas PEDOT layers are more compact. Accordingly, capacitance and charge injection capacity of the composite material exceed those of pure PEDOT layers. In vitro cell culture experiments reveal excellent biocompatibility and mechanical stability of both PEDOT and PEDOT-CNT electrodes. Signals recorded from heart muscle cells demonstrate the high S/N ratio achievable with these electrodes. Long-term pulsing experiments confirm stability of charge injection capacity. In conclusion, a robust fabrication procedure for composite PEDOT-CNT electrodes is demonstrated and results show that these electrodes are well suited for stimulation and recording in cardiac and neurophysiological research.

  20. Improvement in mechanical properties of glass fiber fabric/PVC composites with chopped glass fibers and coupling agent

    Science.gov (United States)

    Lee, Jaewoong; Park, Su Bin; Lee, Joon Seok; Kim, Jong Won

    2017-07-01

    Glass fiber reinforced polyvinylchloride (PVC) composite is used widely because of its low price, chemical resistance, and dimensional stability, but most are short fiber reinforced PVC composites. Fabric reinforced composite have undulated regions, which is the only region without fiber, due to the characteristics of the weave construction, and it limits increasing the mechanical properties. Therefore, in this study, to increase the mechanical properties, the undulated regions of the glass fiber fabric/PVC composite were filled with a silane coupling agent treated chopped fiber. The physical properties, dynamic mechanical thermal properties, and mechanical properties of the prepared composite were observed. The critical fiber aspect ratio of the chopped fiber is different for each mechanical property. This shows that the fabric-reinforced composite of chopped fibers affect each of the mechanical properties differently. In addition, the silane coupling treatment increases the compatibility of the composite components, improving the mechanical properties.

  1. Thermal shock cycling effect on the mechanical behavior of epoxy matrix-woven flax fabric composites

    Science.gov (United States)

    Papanicolaou, G. C.; Chalkias, D. A.; Koutsomitopoulou, A. F.

    2018-02-01

    Thermal fatigue occurs in many engineering constructions, made of polymeric composites, during several applications. Due to the structural heterogeneity of composite materials the fatigue damage after large cyclic temperature variation is complex. It is important to examine thermal fatigue, studying the parameters affecting the process and if possible, describe their effect through mathematical equations in order to predict the properties degradation of the fatigued composites. In the present investigation epoxy matrix-woven flax fabric composites were fabricated and subsequently submitted to thermal shock cycling. Next, their mechanical behavior was studied through quasi-static 3-point bending tests. Thermal shock cycling experiments, of a maximum number of 200 thermal cycles, were performed, each cycle consisted of a 10 minutes exposure of composite specimens in an oven at 50 °C, followed by an abrupt exposure of the same specimens in a freezer for another 10 minutes at -20 °C. From the entire study, it was found that there is a certain number of cycles above which damage increases rapidly, reaching a plateau where saturation of micro-damage is attained. Finally, it is worth to mentioning that all experimental results were accurately predicted by applying the RPM model (Residual Property Model), a semi-analytical predictive model developed by the corresponding author.

  2. Fabrication and characterisation of a novel biomimetic anisotropic ceramic/polymer-infiltrated composite material.

    Science.gov (United States)

    Al-Jawoosh, Sara; Ireland, Anthony; Su, Bo

    2018-04-10

    To fabricate and characterise a novel biomimetic composite material consisting of aligned porous ceramic preforms infiltrated with polymer. Freeze-casting was used to fabricate and control the microstructure and porosity of ceramic preforms, which were subsequently infiltrated with 40-50% by volume UDMA-TEGDMA polymer. The composite materials were then subjected to characterisation, namely density, compression, three-point bend, hardness and fracture toughness testing. Samples were also subjected to scanning electron microscopy and computerised tomography (Micro-CT). Three-dimensional aligned honeycomb-like ceramic structures were produced and full interpenetration of the polymer phase was observed using micro-CT. Depending on the volume fraction of the ceramic preform, the density of the final composite ranged from 2.92 to 3.36g/cm 3 , compressive strength ranged from 206.26 to 253.97MPa, flexural strength from 97.73 to 145.65MPa, hardness ranged from 1.46 to 1.62GPa, and fracture toughness from 3.91 to 4.86MPam 1/2 . Freeze-casting provides a novel method to engineer composite materials with a unique aligned honeycomb-like interpenetrating structure, consisting of two continuous phases, inorganic and organic. There was a correlation between the ceramic fraction and the subsequent, density, strength, hardness and fracture toughness of the composite material. Copyright © 2018 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.

  3. Evaluation of Carbon Composite Overwrap Pressure Vessels Fabricated Using Ionic Liquid Epoxies Project

    Science.gov (United States)

    Grugel, Richard

    2015-01-01

    The intent of the work proposed here is to ascertain the viability of ionic liquid (IL) epoxy based carbon fiber composites for use as storage tanks at cryogenic temperatures. This IL epoxy has been specifically developed to address composite cryogenic tank challenges associated with achieving NASA's in-space propulsion and exploration goals. Our initial work showed that an unadulterated ionic liquid (IL) carbon-fiber composite exhibited improved properties over an optimized commercial product at cryogenic temperatures. Subsequent investigative work has significantly improved the IL epoxy and our first carbon-fiber Composite Overwrap Pressure Vessel (COPV) was successfully fabricated. Here additional COPVs, using a further improved IL epoxy, will be fabricated and pressure tested at cryogenic temperatures with the results rigorously analyzed. Investigation of the IL composite for lower pressure liner-less cryogenic tank applications will also be initiated. It is expected that the current Technology Readiness Level (TRL) will be raised from about TRL 3 to TRL 5 where unambiguous predictions for subsequent development/testing can be made.

  4. Static Strength of Adhesively-bonded Woven Fabric Kenaf Composite Plates

    Science.gov (United States)

    Hilton, Ahmad; Lee, Sim Yee; Supar, Khairi

    2017-06-01

    Natural fibers are potentially used as reinforcing materials and combined with epoxy resin as matrix system to form a superior specific strength (or stiffness) materials known as composite materials. The advantages of implementing natural fibers such as kenaf fibers are renewable, less hazardous during fabrication and handling process; and relatively cheap compared to synthetic fibers. The aim of current work is to conduct a parametric study on static strength of adhesively bonded woven fabric kenaf composite plates. Fabrication of composite panels were conducted using hand lay-up techniques, with variation of stacking sequence, over-lap length, joint types and lay-up types as identified in testing series. Quasi-static testing was carried out using mechanical testing following code of practice. Load-displacement profiles were analyzed to study its structural response prior to ultimate failures. It was found that cross-ply lay-up demonstrates better static strength compared to quasi-isotropic lay-up counterparts due to larger volume of 0° plies exhibited in cross-ply lay-up. Consequently, larger overlap length gives better joining strength, as expected, however this promotes to weight penalty in the joining structure. Most samples showed failures within adhesive region known as cohesive failure modes, however, few sample demonstrated interface failure. Good correlations of parametric study were found and discussed in the respective section.

  5. Ultrasonic Transducer Fabricated Using Lead-Free BFO-BTO+Mn Piezoelectric 1-3 Composite

    Directory of Open Access Journals (Sweden)

    Yan Chen

    2015-05-01

    Full Text Available Mn-doped 0.7BiFeO3-0.3BaTiO3 (BFO-0.3BTO+Mn 1% mol lead-free piezoelectric ceramic were fabricated by traditional solid state reaction. The phase structure, microstructure, and ferroelectric properties were investigated. Additionally, lead-free 1–3 composites with 60% volume fraction of BFO-BTO+Mn ceramic were fabricated for ultrasonic transducer applications by a conventional dice-and-fill method. The BFO-BTO+Mn 1-3 composite has a higher electromechanical coupling coefficient (kt = 46.4% and lower acoustic impedance (Za ~ 18 MRayls compared with that of the ceramic. Based on this, lead-free piezoelectric ceramic composite, single element ultrasonic transducer with a center frequency of 2.54 MHz has been fabricated and characterized. The single element transducer exhibits good performance with a broad bandwidth of 53%. The insertion loss of the transducer was about 33.5 dB.

  6. Investigation Of Sound Absorption Properties Of Bark Cloth Nonwoven Fabric And Composites

    Directory of Open Access Journals (Sweden)

    Rwawiire Samson

    2015-09-01

    Full Text Available The quest for sound-absorbing materials that are not only environmentally friendly, but also sustainable is the foremost reason for natural fibre-acoustic materials. Bark cloth is a natural non-woven fabric that is largely produced from Ficus trees. An exploratory investigation of bark cloth a non-woven material and its reinforcement in epoxy polymer composites has been fabricated and investigated for the sound absorption properties so as to find the most suitable applications and also to see whether bark cloth can be used in some applications in place of man-made fibres. Three types of material species were investigated with their respective composites. The fibre morphology showed bark cloth to be a porous fabric that showed promising sound absorption properties at higher frequencies. The sound absorption results of four-layer material selections of Ficus natalensis, Ficus brachypoda and Antiaris toxicaria bark cloth showed sound absorption coefficient of 0.7; 0.71 and 0.91 at f > 6400 Hz, respectively. The bark cloth reinforced laminar epoxy composites had reduced sound absorption coefficients, which ranged from 0.1 to 0.35, which was attributed to decreased porosity and vibration in the bark cloth fibre network.

  7. Magnetic composite nanofibers fabricated by electrospinning of Fe3O4/gelatin aqueous solutions

    International Nuclear Information System (INIS)

    Wang, Shuhong; Sun, Zhiyao; Yan, Eryun; Yuan, Jihong; Gao, Yang; Bai, Yuhao; Chen, Yu; Wang, Cheng; Zheng, Yongjie; Jing, Tao

    2014-01-01

    Graphical abstract: Superparamagnetic Fe 3 O 4 /GE composite nanofibers with saturation magnetization of 12.87 emμ g −1 were prepared from gelatin aqueous solution at an elevated temperature by electrospinning. - Highlights: • Electrospinning GE aqueous solution at higher temperature. • Presenting a simple and effective technique, combining wet blending with high temperature electrospinning to prepare magnetic composite nanofibers. • Developing composite nanofibers with higher superparamagnetic properties is expected to be useful in application for the biomedical field. - Abstract: We have fabricated magnetic composite nanofibers containing superparamagnetic Fe 3 O 4 nanoparticles by the electrospinning method. Highly dispersed Fe 3 O 4 magnetic nanoparticles were synthesized by one-step co-precipitation of Fe 2+ /Fe 3+ under an alkaline condition with 4 wt% poly(vinyl alcohol) (PVA) aqueous solution as the stabilizer. Gelatin (GE) was used as a polymeric matrix for fabricating the nanocomposites. The prepared Fe 3 O 4 /GE composite nanofibers were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD), respectively. These composite nanofibers show uniform and continuous morphology with the Fe 3 O 4 nanoparticles embedded in the nanofibers. By studying the magnetic properties of the Fe 3 O 4 /GE composite nanofibers, we confirm that the composite nanofibers possess superparamagnetic properties with a high saturated magnetization (M s = 12.87 emμ g −1 ) at room temperature. The features of this approach for getting one-dimensional magnetic nanostructure are its simplicity, effectiveness and safety. The Fe 3 O 4 /GE nanofibers with superparamagnetic properties would be potentially applied in biomedical field

  8. Nonlinear optical properties of Cu nanoclusters by ion implantation in silicate glass

    Science.gov (United States)

    Wang, Y. H.; Wang, Y. M.; Lu, J. D.; Ji, L. L.; Zang, R. G.; Wang, R. W.

    2010-02-01

    Metal nanocluster composite glass prepared by 180 keV Cu ions into silica with dose of 1 × 10 17 ions/cm 2 has been studied. The microstructural properties of the nanoclusters were analysed by optical absorption spectra and transmission electron microscopy (TEM). Third-order nonlinear optical properties of the nanoclusters were measured at 1064 nm and 532 nm excitations using Z-scan technique. The nonlinear refraction index, nonlinear absorption coefficient, and the real and imaginary parts of the third-order nonlinear susceptibility were deduced. The mechanisms responsible for the nonlinear response were discussed. Absolute third-order nonlinear susceptibility χ of this kind of sample was determined to be 2.1 × 10 -7 esu at 532 nm and 1.2 × 10 -7 esu at 1064 nm, respectively.

  9. Easily fabricated and lightweight PPy/PDA/AgNW composites for excellent electromagnetic interference shielding.

    Science.gov (United States)

    Wang, Yan; Gu, Fu-Qiang; Ni, Li-Juan; Liang, Kun; Marcus, Kyle; Liu, Shu-Li; Yang, Fan; Chen, Jin-Ju; Feng, Zhe-Sheng

    2017-11-30

    Conductive polymer composites (CPCs) containing nanoscale conductive fillers have been widely studied for their potential use in various applications. In this paper, polypyrrole (PPy)/polydopamine (PDA)/silver nanowire (AgNW) composites with high electromagnetic interference (EMI) shielding performance, good adhesion ability and light weight are successfully fabricated via a simple in situ polymerization method followed by a mixture process. Benefiting from the intrinsic adhesion properties of PDA, the adhesion ability and mechanical properties of the PPy/PDA/AgNW composites are significantly improved. The incorporation of AgNWs endows the functionalized PPy with tunable electrical conductivity and enhanced EMI shielding effectiveness (SE). By adjusting the AgNW loading degree in the PPy/PDA/AgNW composites from 0 to 50 wt%, the electrical conductivity of the composites greatly increases from 0.01 to 1206.72 S cm -1 , and the EMI SE of the composites changes from 6.5 to 48.4 dB accordingly (8.0-12.0 GHz, X-band). Moreover, due to the extremely low density of PPy, the PPy/PDA/AgNW (20 wt%) composites show a superior light weight of 0.28 g cm -3 . In general, it can be concluded that the PPy/PDA/AgNW composites with tunable electrical conductivity, good adhesion properties and light weight can be used as excellent EMI shielding materials.

  10. Nanoclusters a bridge across disciplines

    CERN Document Server

    Jena, Purusottam

    2010-01-01

    This comprehensive book on Nanoclusters comprises sixteen authoritative chapters written by leading researchers in the field. It provides insight into topics that are currently at the cutting edge of cluster science, with the main focus on metal and metal compound systems that are of particular interest in materials science, and also on aspects related to biology and medicine. While there are numerous books on clusters, the focus on clusters as a bridge across disciplines sets this book apart from others. Delivers cutting edge coverage of cluster science Covers a broad range of topics in

  11. One-pot fabrication of chitin-shellac composite microspheres for efficient enzyme immobilization.

    Science.gov (United States)

    Mei, Shuang; Han, Pingping; Wu, Hong; Shi, Jiafu; Tang, Lei; Jiang, Zhongyi

    2018-01-20

    In this study, all-natural composite microspheres were fabricated through adding shellac into chitin solution followed by self-assembly via thermally-induced phase separation. The pore structure of the composite microspheres was altered into wedge-shape from ink-bottle-shape of the chitin microspheres, whereas, the crystalline structure of these two kinds of microspheres remained unaltered. The as-fabricated chitin-shellac composite microspheres were used for enzyme immobilization through adsorption. And yeast alcohol dehydrogenase (YADH) was chosen as the model enzyme, which is a multimer consisting of 4 subunits. The loading capacity of the as-prepared composite microspheres was up to 79.0mg/g (enzyme/carrier). The immobilized enzyme exhibited a comparable catalytic activity compared to its free counterpart and maintained 49.3% of its initial activity after 54days' storage at 4°C while the free enzyme lost all its activity. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Comparison of tensile strength of different carbon fabric reinforced epoxy composites

    Directory of Open Access Journals (Sweden)

    Jane Maria Faulstich de Paiva

    2006-03-01

    Full Text Available Carbon fabric/epoxy composites are materials used in aeronautical industry to manufacture several components as flaps, aileron, landing-gear doors and others. To evaluate these materials become important to know their mechanical properties, for example, the tensile strength. Tensile tests are usually performed in aeronautical industry to determinate tensile property data for material specifications, quality assurance and structural analysis. For this work, it was manufactured four different laminate families (F155/PW, F155/HS, F584/PW and F584/HS using pre-impregnated materials (prepregs based on F155TM and F584TM epoxy resins reinforced with carbon fiber fabric styles Plain Weave (PW and Eight Harness Satin (8HS. The matrix F155TM code is an epoxy resin type DGEBA (diglycidil ether of bisphenol A that contains a curing agent and the F584TM code is a modified epoxy resin type. The laminates were obtained by handing lay-up process following an appropriate curing cycle in autoclave. The samples were evaluated by tensile tests according to the ASTM D3039. The F584/PW laminates presented the highest values of tensile strength. However, the highest modulus results were determined for the 8HS composite laminates. The correlation of these results emphasizes the importance of the adequate combination of the polymeric matrix and the reinforcement arrangement in the structural composite manufacture. The microscopic analyses of the tested specimens show valid failure modes for composites used in aeronautical industry.

  13. Ultra-high dispersion of graphene in polymer composite via solvent free fabrication and functionalization

    Science.gov (United States)

    Noh, Ye Ji; Joh, Han-Ik; Yu, Jaesang; Hwang, Soon Hyoun; Lee, Sungho; Lee, Cheol Ho; Kim, Seong Yun; Youn, Jae Ryoun

    2015-03-01

    The drying process of graphene-polymer composites fabricated by solution-processing for excellent dispersion is time consuming and suffers from a restacking problem. Here, we have developed an innovative method to fabricate polymer composites with well dispersed graphene particles in the matrix resin by using solvent free powder mixing and in-situ polymerization of a low viscosity oligomer resin. We also prepared composites filled with up to 20 wt% of graphene particles by the solvent free process while maintaining a high degree of dispersion. The electrical conductivity of the composite, one of the most significant properties affected by the dispersion, was consistent with the theoretically obtained effective electrical conductivity based on the mean field micromechanical analysis with the Mori-Tanaka model assuming ideal dispersion. It can be confirmed by looking at the statistical results of the filler-to-filler distance obtained from the digital processing of the fracture surface images that the various oxygenated functional groups of graphene oxide can help improve the dispersion of the filler and that the introduction of large phenyl groups to the graphene basal plane has a positive effect on the dispersion.

  14. Fabrication and thermophysical property characterization of UN/U3Si2 composite fuel forms

    Science.gov (United States)

    White, J. T.; Travis, A. W.; Dunwoody, J. T.; Nelson, A. T.

    2017-11-01

    High uranium density composite fuels composed of UN and U3Si2 have been fabricated using a liquid phase sintering route at temperatures between 1873 K and 1973 K and spanning compositions of 10 vol% to 40 vol% U3Si2. Microstructural analysis and phase characterization revealed the formation of an U-Si-N phase of unknown structure. Microcracking was observed in the U-Si portion of the composite microstructure that likely originates from the mismatched coefficient of thermal expansion between the UN and U3Si2 leading to stresses on heating and cooling of the composite. Thermal expansion coefficient, thermal diffusivity, and thermal conductivity were characterized for each of the compositions as a function of temperature to 1673 K. Hysteresis is observed in the thermal diffusivity for the 20 vol% through 40 vol% specimens between room temperature and 1273 K, which is attributed to the microcracking in the U-Si phase. Thermal conductivity of the composites was modeled using the MOOSE framework based on the collected microstructure data. The impact of irradiation on thermal conductivity was also simulated for this class of composite materials.

  15. Investigation on Shielding and Mechanical Behavior of Carbon/Stainless Steel Hybrid Yarn Woven Fabrics and Their Composites

    Science.gov (United States)

    Jagatheesan, Krishnasamy; Ramasamy, Alagirusamy; Das, Apurba; Basu, Ananjan

    2017-08-01

    This study investigates the shielding characteristics of carbon/stainless steel/polypropylene (C/SS/PP) hybrid woven fabrics and their composites in low frequency (50 MHz-1.5 GHz) and C band (4-6 GHz) regions. The hybrid yarns prepared from carbon and SS filaments using a direct twisting machine have been made into woven fabric samples using a sample loom. The composite has been made by sandwiching a hybrid yarn fabric between the polypropylene films in a compression molding machine at 180°C for 5 min. The shielding behavior of the fabric and the composites has been tested using a coaxial transmission holder for the low frequency range and a wave guide method for the C band frequency range. It has been observed that a 1 end float composite showed a higher SE of 81.4 dB than the 4 end float (76.2 dB) and the 8 end float composites (64 dB) at the low frequency region. However, at the C band frequency, the effect of fabric structures on shielding effectiveness (SE) of fabric composite depends on thread density. For example, at low thread density, (i.e.) 3.93 ppcm, the 8 end float fabric composite showed the highest SE of 22.7 dB than did the 4 end (20.4 dB) and the 1 end float (16.5 dB) fabric composite. However, at high thread density (6.3 ppcm), the case was the reverse. The 1 end float fabric composite showed the highest SE of 29.7 dB rather than 4 end and 8 end float fabric composites (25.9 dB). In addition, all the composites showed less SE than their fabric forms. The increase in thread density also increased the shielding behavior of composites in both frequency ranges. A nonlinear regression model was developed using the Box-Behnken design for predicting the shielding behavior of fabric composites in C band region. In addition to shielding behavior, mechanical strength of C/SS/PP hybrid yarn, the fabric and composite has been tested using a Zwick Roell tensile tester. It has been observed that the work of rupture of C/SS/PP hybrid yarn is higher (6830.3 g

  16. Effects of the Addition of Sodium Alginate and the Concentration of Calcium Chloride on the Properties of Composite Nonwoven Fabrics

    Directory of Open Access Journals (Sweden)

    Lou Ching-Wen

    2016-01-01

    Full Text Available Nonwoven fabrics have merits, and for example, they can be simply and quickly processed with a variety of materials and an easily changeable manufacturing process. This study aims to examine the influences of the addition of sodium alginate (SA and the concentration of calcium chloride (CaCl2 on the properties of the composite nonwoven fabrics. Chitosan (CS micro-particles and SA solution are cross-linked with CaCl2 with various concentrations, combined with farir heat preservative staples (FT/cotton (C nonwoven fabrics, and then freeze-dried to form CS/SA/FT/C composite nonwoven fabrics. Afterwards, physical property tests are performed on the resulting composite nonwoven fabrics to determine their properties as related to various concentrations of CaCl2. The addition of SA decreases the water vapor permeability of FT/C nonwoven fabrics by 15 %, but the concentrations of CaCl2 do not influence the water vapor permeability. Compared to FT/C nonwoven fabrics, CS/SA/FT/C composite nonwoven fabrics have significantly lower water absorbency and water vapor permeability, but a greater stiffness.

  17. Studies on the chemical resistance and mechanical properties of natural polyalthia cerasoides woven fabric/glass hybridized epoxy composites

    CSIR Research Space (South Africa)

    Jayaramudu, J

    2015-01-01

    Full Text Available In the present work, natural Polyalthiacerasoide woven fabrics were extracted from the bark of the tree and using these woven fabrics/glass fibre as reinforcements and epoxy as matrix the hybrid composites were prepared by the hand lay-up technique...

  18. Investigation of Springback Associated with Composite Material Component Fabrication (MSFC Center Director's Discretionary Fund Final Report, Project 94-09)

    Science.gov (United States)

    Benzie, M. A.

    1998-01-01

    The objective of this research project was to examine processing and design parameters in the fabrication of composite components to obtain a better understanding and attempt to minimize springback associated with composite materials. To accomplish this, both processing and design parameters were included in a Taguchi-designed experiment. Composite angled panels were fabricated, by hand layup techniques, and the fabricated panels were inspected for springback effects. This experiment yielded several significant results. The confirmation experiment validated the reproducibility of the factorial effects, error recognized, and experiment as reliable. The material used in the design of tooling needs to be a major consideration when fabricating composite components, as expected. The factors dealing with resin flow, however, raise several potentially serious material and design questions. These questions must be dealt with up front in order to minimize springback: viscosity of the resin, vacuum bagging of the part for cure, and the curing method selected. These factors directly affect design, material selection, and processing methods.

  19. The Fabrication and Characterization of PCL/Rice Husk Derived Bioactive Glass-Ceramic Composite Scaffolds

    Directory of Open Access Journals (Sweden)

    Farnaz Naghizadeh

    2014-01-01

    Full Text Available The present study was conducted to fabricate a 3D scaffold using polycaprolactone (PCL and silicate based bioactive glass-ceramic (R-SBgC. Different concentrations of R-SBgC prepared from rice husk ash (RHA were combined with PCL to fabricate a composite scaffold using thermally induced phase separation (TIPS method. The products were then characterized using SEM and EDX. The results demonstrated that R-SBgC in PCL matrix produced a bioactive material which has highly porous structure with interconnected porosities. There appears to be a relationship between the increase in R-SBgC concentration and increased material density and compressive modulus; however, increasing R-SBgC concentration result in reduced scaffold porosity. In conclusion, it is possible to fabricate a PCL/bioactive glass-ceramic composite from processed rice husk. Varying the R-SBgC concentrations can control the properties of this material, which is useful in the development of the ideal scaffold intended for use as a bone substitute in nonload bearing sites.

  20. Green Composites Reinforced with Plant-Based Fabrics: Cost and Eco-Impact Assessment

    Directory of Open Access Journals (Sweden)

    Georgios Koronis

    2018-02-01

    Full Text Available This study considers a green composite under a twofold assessment; evaluating its process-based cost and environmental footprint profile. The initial objective was to project the manufacturing cost and allow for an additional material comparison of alternative scenarios in the resin transfer molding processes. The additional aim is to have an intermediate environmental assessment to assist in selecting materials and adjust manufacturing parameters which would minimize the energy spent and the CO2 emissions. As it has been noted in numerous applications, the incorporation of natural fiber fabrics, as opposed to glass fabrics, bring together weight savings and consequently cost savings. However, the economic analysis suggests that a glass reinforced composite is marginally cheaper at the production volume of 300 parts (1.9% lower cost in contrast to a possible green solution (ramie. Considering jute instead of ramie as a reinforcement, the cost gets immediately lower, and further decreases with proposed improvements to the manufacturing process. Additional reduction of up to 10% in the production cost can be achieved by process upgrade. As indicated by the Eco-Audit analysis, 36% less energy and 44% CO2 per kilo will be generated, respectively when swapping from glass to ramie fabrics in the production of the automotive hood.

  1. Fabrication of bioinspired composite nanofiber membranes with robust superhydrophobicity for direct contact membrane distillation.

    Science.gov (United States)

    Liao, Yuan; Wang, Rong; Fane, Anthony G

    2014-06-03

    The practical application of membrane distillation (MD) for water purification is hindered by the absence of desirable membranes that can fulfill the special requirements of the MD process. Compared to the membranes fabricated by other methods, nanofiber membranes produced by electrospinning are of great interest due to their high porosity, low tortuosity, large surface pore size, and high surface hydrophobicity. However, the stable performance of the nanofiber membranes in the MD process is still unsatisfactory. Inspired by the unique structure of the lotus leaf, this study aimed to develop a strategy to construct superhydrophobic composite nanofiber membranes with robust superhydrophobicity and high porosity suitable for use in MD. The newly developed membrane consists of a superhydrophobic silica-PVDF composite selective skin formed on a polyvinylidene fluoride (PVDF) porous nanofiber scaffold via electrospinning. This fabrication method could be easily scaled up due to its simple preparation procedures. The effects of silica diameter and concentration on membrane contact angle, sliding angle, and MD performance were investigated thoroughly. For the first time, the direct contact membrane distillation (DCMD) tests demonstrate that the newly developed membranes are able to present stable high performance over 50 h of testing time, and the superhydrophobic selective layer exhibits excellent durability in ultrasonic treatment and a continuous DCMD test. It is believed that this novel design strategy has great potential for MD membrane fabrication.

  2. Improved Strength and Toughness of Carbon Woven Fabric Composites with Functionalized MWCNTs

    Directory of Open Access Journals (Sweden)

    Eslam Soliman

    2014-06-01

    Full Text Available This investigation examines the role of carboxyl functionalized multi-walled carbon nanotubes (COOH-MWCNTs in the on- and off-axis flexure and the shear responses of thin carbon woven fabric composite plates. The chemically functionalized COOH-MWCNTs were used to fabricate epoxy nanocomposites and, subsequently, carbon woven fabric plates to be tested on flexure and shear. In addition to the neat epoxy, three loadings of COOH-MWCNTs were examined: 0.5 wt%, 1.0 wt% and 1.5 wt% of epoxy. While no significant statistical difference in the flexure response of the on-axis specimens was observed, significant increases in the flexure strength, modulus and toughness of the off-axis specimens were observed. The average increase in flexure strength and flexure modulus with the addition of 1.5 wt% COOH-MWCNTs improved by 28% and 19%, respectively. Finite element modeling is used to demonstrate fiber domination in on-axis flexure behavior and matrix domination in off-axis flexure behavior. Furthermore, the 1.5 wt% COOH-MWCNTs increased the toughness of carbon woven composites tested on shear by 33%. Microstructural investigation using Fourier Transform Infrared Spectroscopy (FTIR proves the existence of chemical bonds between the COOH-MWCNTs and the epoxy matrix.

  3. Vibration characteristics of Ni-Ti pseudo-elastic wire inter-weaved fabric composites

    Science.gov (United States)

    Xu, Lei; Wang, Rui; Yang, Qiuhong; Dong, Li

    2009-07-01

    This paper presents a study on the vibration characteristics of Ni-Ti wire inter-weaved glass fabric/epoxy composites. The Ni-Ti pseudo-elastic wires were used as warp yarns and embedded in the fabric preforms with various weaving methods. Dynamic Mechanical Analyzer (DMA) and vibration test technique were used to reveal the dynamical behaviors of specimens in different frequencies of vibration. The storage modulus E', the loss tanδ, the natural frequency f and damping ratio η were examined. The energy dissipation behaviors of the Ni-Ti pseudo-elastic wire, the geometry of textile fabric was also studied. The effect of weaving method on the vibration behavior in Shape Memory Alloy (SMA) based textile composites was considered. The results showed that: (I) the energy dissipation capacity of the wire could be significantly improved by increasing the tensile strain and speed, but slightly affected by loading frequency; (II) the woven of few Ni-Ti warps caused the increase of the storage modulus and the change of the loss tanδ. In the buckling vibration, the damping effects of Ni-Ti pseudo-elastic wires vary with the woven structures. The compact woven structure with proper Ni-Ti warp architectures would receive a small amplitude and good damping.

  4. End-of-cure sensing using ultrasonics for autoclave fabrication of composites

    Science.gov (United States)

    Biermann, Paul J.; Cranmer, Joan H.; Nove, Carol A.; Brown, Lawrence M.

    1996-11-01

    The objective of this work was to demonstrate the use of ultrasonics to determine the end-of-curve for autoclave cured, graphite/epoxy composite laminates. The fundamental benefit of this work will be understanding when to complete the temperature hold and cool down the autoclave and, therefore, consistently produce composite laminates with the desired material properties. An additional benefit is the ability to follow the changing viscosity of the resin during the initial part of the cure. The general approach to this program involved using pulse-echo ultrasonics to measure the transit time for longitudinal ultrasonic waves to pass through a graphite/epoxy composite laminate during cure. Sixteen, 32 and 64 ply (0/90)s graphite/Fiberite 934 epoxy panels were fabricated and cured to various end-of-cure conditions. Additionally, panels with various starting conditions were run. Sound speed was calculated using the panel thickness divided by the measured transit time.

  5. Fabrication and AE characteristics of TiNi/A16061 shape memory alloy composite

    International Nuclear Information System (INIS)

    Park, Young Chul; Lee, Jin Kyung

    2004-01-01

    TiNi/A16061 Shape Memory Alloy (SMA) composite was fabricated by hot press method to investigate the microstructure and mechanical properties. Interface bonding between TiNi reinforcement and A1 matrix was observed by using SEM and EDS. Pre-strain was imposed to generate compressive residual stress inside composite. A tensile test for specimen, which underwent pre-strain, was performed at high temperature to evaluate the variation of strength and the effect of pre-strain. It was shown that interfacial reactions occurred at the bonding between matrix and fiber, creating two inter-metallic layers. And yield stress increased with the amount of pre-strain. Acoustic emission technique was also used to nondestructively clarify the microscopic damage behavior at high temperature and the effect of pre-strain of TiNi/A16061 SMA composite

  6. Sub wavelength Microstructures Fabrication by Self-Organization Processes in Photopolymerizable Nano composite

    International Nuclear Information System (INIS)

    Denisyuk, I.Yu.; Sobeshuk, N.O.; Burunkova, J.A.; Vorzobova, N.D.

    2012-01-01

    This paper describes our research results on nanometers sizes sub wavelength nano structure fabrication by UV curing of special nano composite material with self-organization and light self-focusing effects. For this purpose, special UV curable nano composite material with a set of effects was developing: light self-focusing in the photo polymer with positive refractive index change, self-organization based on photo-induced nanoparticles transportation, and oxygen-based polymerization threshold. Both holographic and projection lithography writing methods application for microstructure making shows geometrical optical laws perturbation as result of nano composite self-organization effects with formation of nanometers-sized high-aspect-ratio structures. Obtained results will be useful for diffraction limit overcoming in projection lithography as well as for deep lithography technique.

  7. On carbide particle reinforced Al composites fabricated by pressureless infiltration technique

    Energy Technology Data Exchange (ETDEWEB)

    Lee, K.B.; Sim, H.S.; Kwon, H. [School of Advanced Materials Engineering, Kookmin Univ., Seoul (Korea); Yang, H.R. [Dept. of Mechanical Engineering, Incheon City Coll., Incheon (Korea)

    2005-07-01

    5052 Al matrix composites reinforced with carbide particles (SiC, TiC, and B{sub 4}C) were fabricated by the pressureless infiltration and the tensile properties were analyzed. The strength values in the control Al were significantly increased over those of the commercial alloy while the strain to failure of the former decreased. Strength values in the composite reinforced with carbide particles were further increased compared to the control alloys. It was observed that strengthening effect by an addition of reinforcement varied with according to reinforcement types. By relative comparison, both TiC and B{sub 4}C particles may be effective reinforcement compared to SiC particles in Al matrix composites. (orig.)

  8. Three-dimensional atom probe microscopy study of interphase precipitation and nanoclusters in thermomechanically treated titanium–molybdenum steels

    International Nuclear Information System (INIS)

    Mukherjee, S.; Timokhina, I.B.; Zhu, C.; Ringer, S.P.; Hodgson, P.D.

    2013-01-01

    Atom probe microscopy was used to generate tomographic analyses of solute clustering and precipitation reactions in a Ti–Mo added microalloyed steel under simulated strip-rolling conditions. It was observed that the interphase row spacing of precipitates was reduced with the application of a pre-strain. The atom probe data also revealed the coexistence of nanoclusters and precipitate particles, even after isothermal holding for 3600 s. These microstructural features occurred both within 3-D interphase precipitate sheets, and in randomly selected fields of view. A bimodal distribution of larger (∼8–10 nm) precipitates coexisted with smaller nanoclusters (∼3 nm) within the interphase sheets/rows. Both the nanoclusters and the precipitates possessed a disc morphology, although nanoclusters with less than ∼30 atoms were more irregular in shape. The size of the nanoclusters and the precipitates was expressed as a Guinier radius, and this varied between 0.5 and 8 nm for both strain conditions, with the average size ∼1.8 nm. The composition of the nanoclusters varied over a wide range, yet was mostly rich in C. All of the nanoclusters and precipitates consisted of a mixture of Ti, Mo and C and the average precipitate composition was close to that of MC carbide stoichiometry, where M represents a mixture of Ti and Mo. In the majority of cases, the Ti/Mo ratio in the MC carbides was > 1. As the Guinier radius increased above 2.5 nm, the composition range became narrower, towards the MC carbide stoichiometry, with a small amount of Fe (∼3–12 at.%)

  9. Phosphorescent Nanocluster Light-Emitting Diodes.

    Science.gov (United States)

    Kuttipillai, Padmanaban S; Zhao, Yimu; Traverse, Christopher J; Staples, Richard J; Levine, Benjamin G; Lunt, Richard R

    2016-01-13

    Devices utilizing an entirely new class of earth abundant, inexpensive phosphorescent emitters based on metal-halide nanoclusters are reported. Light-emitting diodes with tunable performance are demonstrated by varying cation substitution to these nanoclusters. Theoretical calculations provide insight about the nature of the phosphorescent emitting states, which involves a strong pseudo-Jahn-Teller distortion. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Shape memory performance of asymmetrically reinforced epoxy/carbon fibre fabric composites in flexure

    Directory of Open Access Journals (Sweden)

    M. Fejos

    2013-06-01

    Full Text Available In this study asymmetrically reinforced epoxy (EP/carbon fibre (CF fabric composites were prepared and their shape memory properties were quantified in both unconstrained and fully constrained flexural tests performed in a dynamic mechanical analyser (DMA. Asymmetric layering was achieved by incorporating two and four CF fabric layers whereby setting a resin- and reinforcement-rich layer ratio of 1/4 and 1/2, respectively. The recovery stress was markedly increased with increasing CF content. The related stress was always higher when the CF-rich layer experienced tension load locally. Specimens with CF-rich layers on the tension side yielded better shape fixity ratio, than those with reinforcement layering on the compression side. Cyclic unconstrained shape memory tests were also run up to five cycles on specimens having the CF-rich layer under local tension. This resulted in marginal changes in the shape fixity and recovery ratios.

  11. Hybrid Composite Laminates Reinforced with Kevlar/Carbon/Glass Woven Fabrics for Ballistic Impact Testing

    Directory of Open Access Journals (Sweden)

    Elias Randjbaran

    2014-01-01

    Full Text Available Current study reported a facile method to investigate the effects of stacking sequence layers of hybrid composite materials on ballistic energy absorption by running the ballistic test at the high velocity ballistic impact conditions. The velocity and absorbed energy were accordingly calculated as well. The specimens were fabricated from Kevlar, carbon, and glass woven fabrics and resin and were experimentally investigated under impact conditions. All the specimens possessed equal mass, shape, and density; nevertheless, the layers were ordered in different stacking sequence. After running the ballistic test at the same conditions, the final velocities of the cylindrical AISI 4340 Steel pellet showed how much energy was absorbed by the samples. The energy absorption of each sample through the ballistic impact was calculated; accordingly, the proper ballistic impact resistance materials could be found by conducting the test. This paper can be further studied in order to characterise the material properties for the different layers.

  12. Hybrid composite laminates reinforced with Kevlar/carbon/glass woven fabrics for ballistic impact testing.

    Science.gov (United States)

    Randjbaran, Elias; Zahari, Rizal; Jalil, Nawal Aswan Abdul; Majid, Dayang Laila Abang Abdul

    2014-01-01

    Current study reported a facile method to investigate the effects of stacking sequence layers of hybrid composite materials on ballistic energy absorption by running the ballistic test at the high velocity ballistic impact conditions. The velocity and absorbed energy were accordingly calculated as well. The specimens were fabricated from Kevlar, carbon, and glass woven fabrics and resin and were experimentally investigated under impact conditions. All the specimens possessed equal mass, shape, and density; nevertheless, the layers were ordered in different stacking sequence. After running the ballistic test at the same conditions, the final velocities of the cylindrical AISI 4340 Steel pellet showed how much energy was absorbed by the samples. The energy absorption of each sample through the ballistic impact was calculated; accordingly, the proper ballistic impact resistance materials could be found by conducting the test. This paper can be further studied in order to characterise the material properties for the different layers.

  13. Determining the applicability of liquid alloy nitriding in fabrication of Al-AlN particle composites

    Directory of Open Access Journals (Sweden)

    J. Śleziona

    2008-08-01

    Full Text Available One of the possible techniques of the fabrication of dispersion-hardened composites is by in situ reaction between the liquid alloy and gas. The study presents the results of the research on nitriding of liquid aluminium alloy containing Mg and Ti as alloying elements under the conditions of high pressure comprised in the range of 150-1000hPa at the temperature of up to 1100oC. It has been stated that under the applied conditions of the synthesis it is possible to obtain the AlN nitride, but it is formed on the liquid alloy surface and as a deposit on the surface of the crucible. Some results of the analysis of the phase constitution obtained in the fabricated products were presented along with the structure of these products.

  14. Comparative Investigation of Tungsten Fibre Nets Reinforced Tungsten Composite Fabricated by Three Different Methods

    Directory of Open Access Journals (Sweden)

    Linhui Zhang

    2017-07-01

    Full Text Available Tungsten fibre nets reinforced tungsten composites (Wf/W containing four net layers were fabricated by spark plasma sintering (SPS, hot pressing (HP and cold rolling after HP (HPCR, with the weight fraction of fibres being 17.4%, 10.5% and 10.5%, respectively. The relative density of the HPCRed samples is the highest (99.8% while that of the HPed composites is the lowest (95.1%. Optical and scanning electron microscopy and electron back scattering diffraction were exploited to characterize the microstructure, while tensile and hardness tests were used to evaluate the mechanical properties of the samples. It was found that partial recrystallization of fibres occurred after the sintering at 1800 °C. The SPSed and HPed Wf/W composites begin to exhibit plastic deformation at 600 °C with tensile strength (TS of 536 and 425 MPa and total elongation at break (TE of 11.6% and 23.0%, respectively, while the HPCRed Wf/W composites exhibit plastic deformation at around 400 °C. The TS and TE of the HPCRed Wf/W composites at 400 °C are 784 MPa and 8.4%, respectively. The enhanced mechanical performance of the Wf/W composites over the pure tungsten can be attributed to the necking, cracking, and debonding of the tungsten fibres.

  15. Fabrication process optimization for improved mechanical properties of Al 7075/SiCp metal matrix composites

    Directory of Open Access Journals (Sweden)

    Dipti Kanta Das

    2016-04-01

    Full Text Available Two sets of nine different silicon carbide particulate (SiCp reinforced Al 7075 Metal Matrix Composites (MMCs were fabricated using liquid metallurgy stir casting process. Mean particle size and weight percentage of the reinforcement were varied according to Taguchi L9 Design of Experiments (DOE. One set of the cast composites were then heat treated to T6 condition. Optical micrographs of the MMCs reveal consistent dispersion of reinforcements in the matrix phase. Mechanical properties were determined for both as-cast and heat treated MMCs for comparison of the experimental results. Linear regression models were developed for mechanical properties of the heat treated MMCs using list square method of regression analysis. The fabrication process parameters were then optimized using Taguchi based grey relational analysis for the multiple mechanical properties of the heat treated MMCs. The largest value of mean grey relational grade was obtained for the composite with mean particle size 6.18 µm and 25 weight % of reinforcement. The optimal combination of process parameters were then verified through confirmation experiments, which resulted 42% of improvement in the grey relational grade. Finally, the percentage of contribution of each process parameter on the multiple performance characteristics was calculated through Analysis of Variance (ANOVA.

  16. Fabrication and Characterization of High Temperature Resin/Carbon Nanofiber Composites

    Science.gov (United States)

    Ghose, Sayata; Watson, Kent A.; Working, Dennis C.; Criss, Jim M.; Siochi, Emilie J.; Connell, John W.

    2005-01-01

    Multifunctional composites present a route to structural weight reduction. Nanoparticles such as carbon nanofibers (CNF) provide a compromise as a lower cost nanosize reinforcement that yields a desirable combination of properties. Blends of PETI-330 and CNFs were prepared and characterized to investigate the potential of CNF composites as a high performance structural medium. Dry mixing techniques were employed and the effect of CNF loading level on melt viscosity was determined. The resulting powders were characterized for degree of mixing, thermal and rheological properties. Based on the characterization results, samples containing 30 and 40 wt% CNF were scaled up to approx.300 g and used to fabricate moldings 10.2 cm x 15.2 cm x 0.32 cm thick. The moldings were fabricated by injecting the mixtures at 260-280 C into a stainless steel tool followed by curing for 1 h at 371 C. The tool was designed to impart high shear during the process in an attempt to achieve some alignment of CNFs in the flow direction. Moldings were obtained that were subsequently characterized for thermal, mechanical and electrical properties. The degree of dispersion and alignment of CNFs were investigated using high-resolution scanning electron microscopy. The preparation and preliminary characterization of PETI-330/CNF composites are discussed. Keywords: resins, carbon nanofibers, scanning electron microscopy, electrical properties, thermal conductivity,injection

  17. Effects of atmosphere composition on fabrication process of hollow glass microspheres in drop-tower furnace

    International Nuclear Information System (INIS)

    Qi Xiaobo; Wei Sheng; Zhang Zhanwen; Li Bo; Chen Sufen; Shi Tao

    2010-01-01

    To fabricate high quality hollow glass microspheres (HGMs) for inertial confinement fusion (ICF) targets by solgel technology, effects of furnace atmosphere composition on the transformation process from gel particles to HGMs and the resulting quality of HGMs were investigated by numerical simulation and experiments. The results show that the furnace atmosphere composition significantly affects the heat and mass transfer process between particles/microspheres and furnace atmosphere, but the falling velocity of the particles/microspheres in drop-tower furnace changes only slightly with the furnace atmosphere compositions. The heating-up rate of gel particles in heat-absorbing stage increases remarkably with the increase of the content of helium in the furnace atmosphere and increasing the helium content accelerates effectively the encapsulation of gel particles. Consequently, higher helium content in furnace atmosphere will result in higher HGM yield with high quality and larger HGM aspect ratio. However, maintaining a proper proportion of helium in the furnace atmosphere is necessary to improve HGM surface smoothness. With the volume percentage of helium ranging from 50% to 80%, HGMs with high sphericity, concentricity and surface smoothness can be fabricated with high yield. (authors)

  18. AC/TiO2/Rubber Composite Sheet Catalysts; Fabrication, Characterization and Photocatalytic Activities

    Directory of Open Access Journals (Sweden)

    Sriwong Chaval

    2015-01-01

    Full Text Available The AC/TiO2/Rubber (ACTR composite sheets weresuccessfully fabricated by a simply mixing of fixed TiO2 suspension and natural rubber latex (60% HA contents withthe varyingamounts of activated carbon (AC suspension, followed by stirring, pouring into apetri dish mold, drying at room temperature (RT, after that taking out from a mold, reversing and drying again at RT. Then, the as-fabricated ACTR composite sheets were characterized by X-ray diffractometer (XRD, attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR, energy dispersive X-ray spectroscopy (EDS and scanning electron microscopy (SEMtechniques. The photocatalytic efficiencies of all ACTR composite sheet samples were evaluated by photo degrading of methylene blue (MB dye solution under UV light irradiation. The results showed that the photocatalytic activity of ACTR sheet with10.0wt%AC loading has the highest efficiency for the photo degradation of MB dye than the other sheets. This is due to the fact that it is relatively with the synergistic effect of well-combined titanium dioxide catalyst and activated carbon adsorbent.

  19. Nylon-Graphene Composite Nonwovens as Monolithic Conductive or Capacitive Fabrics.

    Science.gov (United States)

    Pan, Qin; Shim, Eunkyoung; Pourdeyhimi, Behnam; Gao, Wei

    2017-03-08

    Here we describe a nylon-graphene nonwoven (NGN) composite, prepared via melt-blowing of nylon-6 into nonwoven fabrics and infiltrate those with graphene oxide (GO) in aqueous dispersions, which were further chemically reduced into graphene to offer electrical conductivity. The correlation between the conductivity and the graphene loading is described by the percolation scaling law σ = (p - p c ) t , with an exponent t of 1.2 and a critical concentration p c of 0.005 wt %, the lowest among all the nylon composites reported. Monolithic supercapacitors have been further developed on the nylon-GO nonwoven composites (NGO), via a programed CO 2 -laser patterning process. The nylon nonwoven works as an efficient matrix, providing high capacity to GO and ensuring enough electrode materials generated via the subsequent laser patterning processes. Our best monolithic supercapacitors exhibited an areal capacitance of 10.37 mF cm -2 in PVA-H 2 SO 4 electrolyte, much higher than the 1-3 mF cm -2 reported for typical microsupercapacitors. Moreover, our supercapacitors were able to retain a capacitance density of 5.07 mF cm -2 at an ultrahigh scan rate (1 V s -1 ), probably due to the facilitated ion migration within the highly porous nonwoven framework. This is the first report of highly functional nylon-6 nonwovens, fabricated via industrially scalable pathways into low-cost conductive polymer matrices and disposable energy storage systems.

  20. Study on the friction and wear properties of carbon fabric composites reinforced with micro- and nano-particles

    International Nuclear Information System (INIS)

    Zhang Zhaozhu; Su Fenghua; Wang Kun; Jiang Wei; Men Xuehu; Liu Weimin

    2005-01-01

    The carbon fabric composites filled with the particulates of polyfluo-150 wax (PFW), nano-particles of ZnO (nano-ZnO), and nano-particles of SiC (nano-SiC), respectively, were prepared by dip-coating of the carbon fabric in a phenolic resin containing the particulates to be incorporated and the successive curing. The friction and wear behaviors of the carbon fabric composites sliding against AISI-1045 steel in a pin-on-disk configuration are evaluated on a Xuanwu-III high-temperature friction and wear tester. The morphologies of the worn surfaces of the filled carbon fabric composites and the counterpart steel pins are analyzed by means of scanning electron microscopy. The effect of the fillers on the adhesion strength of the adhesive is evaluated using a DY35 universal materials tester. It is found that the fillers PFW, nano-ZnO, and nano-SiC contribute to significantly increasing anti-wear abilities of the carbon fabric composites, however, nano-SiC increase the friction coefficient of the carbon fabric composites. The wear rates of the composites at elevated temperature above 180 deg. C are much larger than that below 180 deg. C, which attribute to the degradation and decomposition of the adhesive resin at an excessively elevated temperature. That the interface bonding strength among the carbon fabric, the adhesive, and the particles is significantly increased after solidification and with the transferred film of the varied features largely account for the increased wear-resistance of the filled carbon fabric composites as compared with the unfilled one

  1. Fabrication and characterization of laminated SiC composites reinforced with graphene nanoplatelets

    Energy Technology Data Exchange (ETDEWEB)

    Pereira dos Santos Tonello, Karolina, E-mail: karolina.pereira@polito.it; Padovano, Elisa; Badini, Claudio; Biamino, Sara; Pavese, Matteo; Fino, Paolo

    2016-04-06

    Nanosized allotropes of carbon have been attracting a lot of attention recently, but despite the steady growth of the number of scientific works on materials based on graphene family, there is still much to be explored. These two-dimensional carbon materials, such as graphene nanoplatelets, multilayer graphene or few layer graphene have emerged as a possible second phase for reinforcing ceramics, resulting in remarkable properties of these composites. Typically, graphene ceramic matrix composites are prepared by a colloidal or a powder route followed by pressure assisted sintering. Recently other traditional ceramic processes, such as tape casting, were also successfully studied. The aim of this research is to fabricate α-SiC multi-layer composites containing 2, 4 and 8 vol% of graphene nanoplatelets (GNP) by tape casting and study the effect of these additions on the mechanical behavior of the composites. In order to achieve this purpose, samples were pressureless sintered and tested for density and mechanical properties. The elastic modulus was measured by the impulse excitation of vibration method, the hardness by Vickers indentation and fracture toughness using micro Vickers indentation and by three-point bending applying the pre-cracked beam approach. Results showed that up to 4 vol%, the density and mechanical properties were directly proportional to the amount of GNP added but showed a dramatic decrease for 8 vol% of GNP. Composites with 4 vol% of GNP had a 23% increment elastic modulus, while the fracture toughness had a 34% increment compared to SiC tapes fabricated under the same conditions. Higher amounts of GNP induces porosity in the samples, thus decreasing the mechanical properties. This study, therefore, indicates that 4% is an optimal amount of GNP and suggests that excessive amounts of GNP are rather detrimental to the mechanical properties of silicon carbide ceramic materials prepared by tape casting.

  2. Fabrication of metal matrix composite by semi-solid powder processing

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Yufeng [Iowa State Univ., Ames, IA (United States)

    2011-01-01

    Various metal matrix composites (MMCs) are widely used in the automotive, aerospace and electrical industries due to their capability and flexibility in improving the mechanical, thermal and electrical properties of a component. However, current manufacturing technologies may suffer from insufficient process stability and reliability and inadequate economic efficiency and may not be able to satisfy the increasing demands placed on MMCs. Semi-solid powder processing (SPP), a technology that combines traditional powder metallurgy and semi-solid forming methods, has potential to produce MMCs with low cost and high efficiency. In this work, the analytical study and experimental investigation of SPP on the fabrication of MMCs were explored. An analytical model was developed to understand the deformation mechanism of the powder compact in the semi-solid state. The densification behavior of the Al6061 and SiC powder mixtures was investigated with different liquid fractions and SiC volume fractions. The limits of SPP were analyzed in terms of reinforcement phase loading and its impact on the composite microstructure. To explore adoption of new materials, carbon nanotube (CNT) was investigated as a reinforcing material in aluminum matrix using SPP. The process was successfully modeled for the mono-phase powder (Al6061) compaction and the density and density distribution were predicted. The deformation mechanism at low and high liquid fractions was discussed. In addition, the compaction behavior of the ceramic-metal powder mixture was understood, and the SiC loading limit was identified by parametric study. For the fabrication of CNT reinforced Al6061 composite, the mechanical alloying of Al6061-CNT powders was first investigated. A mathematical model was developed to predict the CNT length change during the mechanical alloying process. The effects of mechanical alloying time and processing temperature during SPP were studied on the mechanical, microstructural and

  3. Innovative fabrication processing of advanced composite materials concepts for primary aircraft structures

    Science.gov (United States)

    Kassapoglou, Christos; Dinicola, Al J.; Chou, Jack C.

    1992-01-01

    The autoclave based THERM-X(sub R) process was evaluated by cocuring complex curved panels with frames and stiffeners. The process was shown to result in composite parts of high quality with good compaction at sharp radius regions and corners of intersecting parts. The structural properties of the postbuckled panels fabricated were found to be equivalent to those of conventionally tooled hand laid-up parts. Significant savings in bagging time over conventional tooling were documented. Structural details such as cocured shear ties and embedded stiffener flanges in the skin were found to suppress failure modes such as failure at corners of intersecting members and skin stiffeners separation.

  4. Fabrication, testing and analysis of steel/composite DLS adhesive joints

    DEFF Research Database (Denmark)

    Hashim, S.; Berggreen, Christian; Tsouvalis, N.

    2011-01-01

    This paper describes experimental and numerical techniques to study the structural design of double lap shear joints that are based on thick-adherend steel/steel and steel/composite, with epoxy adhesive. A standard practical fabrication method was used to produce specimens of various dimensions...... and the results showed that joint strength depends largely on materials combination and overlap length. The testing also included the use of an advanced imaging system to determine failure initiation and propagation. Two-dimensional finite element analysis (FEA) stress models were applied and showed...

  5. Fabrication and characterization of laminated Ti-(TiB+La2O3/Ti composite

    Directory of Open Access Journals (Sweden)

    Yuanfei Han

    2015-10-01

    Full Text Available The incorporation of ceramic particulate reinforcements into titanium alloys can improve the specific strength and specific stiffness, while inevitably reduce the plasticity and ductility. In this study, in situ synthesized multilayer Ti-(TiB+La2O3/Ti composite was designed by learning from the microstructure of nature biological materials with excellent mechanical properties. The Ti-(TiB+La2O3/Ti composite with unique characteristic of laminated structure was prepared by combined powder metallurgy and hot rolling. The method has the synthesize advantages with in-situ reaction of Ti and LaB6 at high temperature and controllability of reinforcements size and constituent phases in composites. The result shows that the pores in the as sintered laminated structure composite completely disappeared after hot rolling at 1050 °C. The agglomerated reinforcement particles were well dispersed and distributed uniformly along the rolling direction. The thickness of pure Ti layer and (TiB+La2O3/Ti composite layer decreased from 1 mm to about 200 μm. Meanwhile, the grains size was refined obviously after rolling deformation. The room temperature tensile test indicates that the elongation of the laminated Ti-(TiB+La2O3/Ti composite improved from 13% to 17% in comparison with the uniform (TiB+La2O3/Ti composite, while the tensile strength had little change. It provides theoretical and experimental basis for fabricating the novel high performance laminated Ti-(TiB+La2O3/Ti composites.

  6. Enhanced photocatalytic activity of Bi2WO6/TiO2 composite coated polyester fabric under visible light irradiation

    Science.gov (United States)

    Du, Zoufei; Cheng, Cheng; Tan, Lin; Lan, Jianwu; Jiang, Shouxiang; Zhao, Ludan; Guo, Ronghui

    2018-03-01

    In this study, a visible-light-driven photocatalyst Bi2WO6/TiO2 composite was reported using one-step hydrothermal method and then coated on the polyester fabric. The samples were systematically characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area, UV-vis diffuse reflection spectroscopy and photoluminescence spectroscopy (PL). The photocatalytic activity of Bi2WO6/TiO2 coated polyester fabric was evaluated by degradation of Rhodamine B (RhB) and Methylene blue (MB) under visible light irradiation. The self-cleaning property of the fabrics was assessed through removing red wine stain. The results reveal that the Bi2WO6/TiO2 composites with irregular shape are coated on the polyester fabric successfully. The UV-vis absorption spectra show a broad absorption band in the visible region, which extends the scope of absorption spectrum and helps to improve the photocatalytic degradation efficiency. Photocatalytic activities of the Bi2WO6/TiO2 composite polyester fabric are associated with the content of TiO2. Bi2WO6/15%TiO2 coated polyester fabric exhibits the degradation efficiency for RhB and MB up to 98% and 95.1%, respectively, which is much higher than that of pure Bi2WO6 and TiO2 coated polyester fabric. Moreover, Bi2WO6/15%TiO2 coated polyester fabric shows good cycle stability toward continuous three cycles of photocatalytic experiment for dyes degradation. In addition, the Bi2WO6/TiO2 coated polyester fabric shows good self-cleaning property. This work could be extended to design of other composite photocatalyst coating on the fabric for enhancing activity by coupling suitable wide and narrow band-gap semiconductors.

  7. Silicone nanocomposite coatings for fabrics

    Science.gov (United States)

    Eberts, Kenneth (Inventor); Lee, Stein S. (Inventor); Singhal, Amit (Inventor); Ou, Runqing (Inventor)

    2011-01-01

    A silicone based coating for fabrics utilizing dual nanocomposite fillers providing enhanced mechanical and thermal properties to the silicone base. The first filler includes nanoclusters of polydimethylsiloxane (PDMS) and a metal oxide and a second filler of exfoliated clay nanoparticles. The coating is particularly suitable for inflatable fabrics used in several space, military, and consumer applications, including airbags, parachutes, rafts, boat sails, and inflatable shelters.

  8. Fabrication and evaluation of mechanical properties of alkaline treated sisal/hemp fiber reinforced hybrid composite

    Science.gov (United States)

    Venkatesha Gupta, N. S.; Akash; Sreenivasa Rao, K. V.; kumar, D. S. Arun

    2016-09-01

    Fiber reinforced polymer composite have acquired a dominant place in variety of applications because of higher specific strength and modulus, the plant based natural fiber are partially replacing currently used synthetic fiber as reinforcement for polymer composites. In this research work going to develop a new material which posses a strength to weight ratio that for exceed any of the present material. The hybrid composite sisal/hemp reinforced with epoxy matrix has been developed by compression moulding technique according to ASTM standards. Sodium hydroxide (NAOH) was used as alkali for treating the fibers. The amount of reinforcement was varied from 10% to 50% in steps of 10%. Prepared specimens were examined for mechanical properties such as tensile strength, flexural strength, and hardness. Hybrid composite with 40wt% sisal/hemp fiber were found to posses higher strength (tensile strength = 53.13Mpa and flexural strength = 82.07Mpa) among the fabricated hybrid composite specimens. Hardness value increases with increasing the fiber volume. Morphological examinations are carried out to analyze the interfacial characteristics, internal structure and fractured surfaces by using scanning electron microscope.

  9. High temperature formability of graphene nanoplatelets-AZ31 composites fabricated by stir-casting method

    Directory of Open Access Journals (Sweden)

    Muhammad Rashad

    2016-12-01

    Full Text Available Outstanding mechanical properties of graphene nanoplatelets (GNPs make them ideal reinforcement for mass production of composites. In this research, the composites were fabricated by stir-casting method. GNPs were added in 1.5 and 3.0 wt.% into Mg–3wt.% Al–1wt.% Zn (AZ31 magnesium alloy. As cast ingots were preheated for one hour and extruded at 350 °C with extrusion ratio of 5.2:1. As extruded AZ31-GNPs composites were micro-structurally characterized with X-ray diffraction, optical microscopy and scanning electron microscopy. Vickers micro-hardness of synthesized materials was investigated both in parallel and perpendicular to extrusion directions. Room temperature mechanical testing revealed that with increasing GNP's content, tensile fracture strain was remarkably increased without significant compromise in tensile strength. Furthermore, as extruded AZ31-3GNPs composites were subjected to tensile testing at temperatures ranging from 75 °C to 300 °C with initial strain rate of 2 × 10−3 s−1 to evaluate high temperature formability of composite. It was found that like CNTs, GNPs also have the potential to sustain tensile strength at high temperatures.

  10. Atomically Precise Metal Nanoclusters for Catalytic Application

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Rongchao [Carnegie Mellon Univ., Pittsburgh, PA (United States)

    2016-11-18

    The central goal of this project is to explore the catalytic application of atomically precise gold nanoclusters. By solving the total structures of ligand-protected nanoclusters, we aim to correlate the catalytic properties of metal nanoclusters with their atomic/electronic structures. Such correlation unravel some fundamental aspects of nanocatalysis, such as the nature of particle size effect, origin of catalytic selectivity, particle-support interactions, the identification of catalytically active centers, etc. The well-defined nanocluster catalysts mediate the knowledge gap between single crystal model catalysts and real-world conventional nanocatalysts. These nanoclusters also hold great promise in catalyzing certain types of reactions with extraordinarily high selectivity. These aims are in line with the overall goals of the catalytic science and technology of DOE and advance the BES mission “to support fundamental research to understand, predict, and ultimately control matter and energy at the level of electrons, atoms, and molecules”. Our group has successfully prepared different sized, robust gold nanoclusters protected by thiolates, such as Au25(SR)18, Au28(SR)20, Au38(SR)24, Au99(SR)42, Au144(SR)60, etc. Some of these nanoclusters have been crystallographically characterized through X-ray crystallography. These ultrasmall nanoclusters (< 2 nm diameter) exhibit discrete electronic structures due to quantum size effect, as opposed to quasicontinuous band structure of conventional metal nanoparticles or bulk metals. The available atomic structures (metal core plus surface ligands) of nanoclusters serve as the basis for structure-property correlations. We have investigated the unique catalytic properties of nanoclusters (i.e. not observed in conventional nanogold catalysts) and revealed the structure-selectivity relationships. Highlights of our

  11. A new formaldehyde sensor from silver nanoclusters modified Tollens' reagent.

    Science.gov (United States)

    Chaiendoo, Kanokwan; Sooksin, Sawarin; Kulchat, Sirinan; Promarak, Vinich; Tuntulani, Thawatchai; Ngeontae, Wittaya

    2018-07-30

    A selective colorimetric assay for detecting formaldehyde (FA) was proposed based on silver nanoclusters (AgNCs) templated by polymethacrylic acid (PMAA). The chemodosimeter was easily fabricated by the formation of Tollens' reagent in the presence of AgNCs (AgNCs@Tollens). The detection principle was based on the change in the color caused by the change in the particle size from nanoclusters (no LSPR) to nanoparticles (with LSPR) upon the reduction of Tollens' reagent by FA. In the presence of FA, the intensity of a new absorbance band with a maximum at a wavelength of 430 nm corresponding to the LSPR of the AgNPs linearly increased as a function of the FA concentration, exhibiting a color change that could be observed by the naked eye. This method provided a working range of 30-50 µM with lower detection limit (LOD) of 27.99 µM. The proposed method exhibited excellent selectivity towards FA over other aldehyde-containing compounds. Copyright © 2018 Elsevier Ltd. All rights reserved.

  12. Systematic Study on the Self-Assembled Hexagonal Au Voids, Nano-Clusters and Nanoparticles on GaN (0001.

    Directory of Open Access Journals (Sweden)

    Puran Pandey

    Full Text Available Au nano-clusters and nanoparticles (NPs have been widely utilized in various electronic, optoelectronic, and bio-medical applications due to their great potentials. The size, density and configuration of Au NPs play a vital role in the performance of these devices. In this paper, we present a systematic study on the self-assembled hexagonal Au voids, nano-clusters and NPs fabricated on GaN (0001 by the variation of annealing temperature and deposition amount. At relatively low annealing temperatures between 400 and 600°C, the fabrication of hexagonal shaped Au voids and Au nano-clusters are observed and discussed based on the diffusion limited aggregation model. The size and density of voids and nano-clusters can systematically be controlled. The self-assembled Au NPs are fabricated at comparatively high temperatures from 650 to 800°C based on the Volmer-Weber growth model and also the size and density can be tuned accordingly. The results are symmetrically analyzed and discussed in conjunction with the diffusion theory and thermodynamics by utilizing AFM and SEM images, EDS maps and spectra, FFT power spectra, cross-sectional line-profiles and size and density plots.

  13. Poly (methyl methacrylate) Composites with Size-Selected Silver Nanoparticles Fabricated using Cluster Beam Technique

    DEFF Research Database (Denmark)

    Hanif, Muhammad; Juluri, Raghavendra Rao; Chirumamilla, Manohar

    2016-01-01

    An embedment of metal nanoparticles of well-defined sizes in thin polymer films is of significant interest for a number of practical applications, in particular, for preparing materials with tunable plasmonic properties. In this article, we present a fabrication route for metal–polymer composites...... tendency to flattening upon impact. By controlling the polymer hardness (from viscous to soft state) prior the cluster deposition and annealing conditions after the deposition the degree of immersion of the nanoparticles into polymer can be tuned, thus, making it possible to create composites with either...... particles partly or fully embedded into the film. Good size selection and rather homogeneous dispersion of nanoparticles in the thin polymer film lead to excellent plasmonic properties characterized by the narrow band and high quality factor of localized surface plasmon resonance....

  14. Fabrication of in-situ grown graphene reinforced Cu matrix composites

    Science.gov (United States)

    Chen, Yakun; Zhang, Xiang; Liu, Enzuo; He, Chunnian; Shi, Chunsheng; Li, Jiajun; Nash, Philip; Zhao, Naiqin

    2016-01-01

    Graphene/Cu composites were fabricated through a graphene in-situ grown approach, which involved ball-milling of Cu powders with PMMA as solid carbon source, in-situ growth of graphene on flaky Cu powders and vacuum hot-press sintering. SEM and TEM characterization results indicated that graphene in-situ grown on Cu powders guaranteed a homogeneous dispersion and a good combination between graphene and Cu matrix, as well as the intact structure of graphene, which was beneficial to its strengthening effect. The yield strength of 244 MPa and tensile strength of 274 MPa were achieved in the composite with 0.95 wt.% graphene, which were separately 177% and 27.4% enhancement over pure Cu. Strengthening effect of in-situ grown graphene in the matrix was contributed to load transfer and dislocation strengthening. PMID:26763313

  15. POLYMER COMPOSITE FILMS WITH SIZE-SELECTED METAL NANOPARTICLES FABRICATED BY CLUSTER BEAM TECHNIQUE

    DEFF Research Database (Denmark)

    Ceynowa, F. A.; Chirumamilla, Manohar; Popok, Vladimir

    2017-01-01

    Formation of polymer films with size-selected silver and copper nanoparticles (NPs) is studied. Polymers are prepared by spin coating while NPs are fabricated and deposited utilizing a magnetron sputtering cluster apparatus. The particle embedding into the films is provided by thermal annealing...... after the deposition. The degree of immersion can be controlled by the annealing temperature and time. Together with control of cluster coverage the described approach represents an efficient method for the synthesis of thin polymer composite layers with either partially or fully embedded metal NPs....... Combining electron beam lithography, cluster beam deposition and thermal annealing allows to form ordered arrays of metal NPs on polymer films. Plasticity and flexibility of polymer host and specific properties added by coinage metal NPs open a way for different applications of such composite materials...

  16. Surface enhanced Raman scattering by organic and inorganic semiconductors formed on laterally ordered arrays of Au nanoclusters

    Energy Technology Data Exchange (ETDEWEB)

    Milekhin, Alexander G., E-mail: milekhin@thermo.isp.nsc.ru [A.V. Rzhanov Institute of Semiconductor Physics, Lavrentiev av. 13, 630090, Novosibirsk (Russian Federation); Novosibirsk State University, Pirogov str. 2, 630090, Novosibirsk (Russian Federation); Yeryukov, Nikolay A., E-mail: yeryukov@isp.nsc.ru [A.V. Rzhanov Institute of Semiconductor Physics, Lavrentiev av. 13, 630090, Novosibirsk (Russian Federation); Sveshnikova, Larisa L.; Duda, Tatyana A.; Rodyakina, Ekaterina E. [A.V. Rzhanov Institute of Semiconductor Physics, Lavrentiev av. 13, 630090, Novosibirsk (Russian Federation); Sheremet, Evgeniya S.; Ludemann, Michael; Gordan, Ovidiu D. [Semiconductor Physics, Chemnitz University of Technology, D-09107, Chemnitz (Germany); Latyshev, Alexander V. [A.V. Rzhanov Institute of Semiconductor Physics, Lavrentiev av. 13, 630090, Novosibirsk (Russian Federation); Novosibirsk State University, Pirogov str. 2, 630090, Novosibirsk (Russian Federation); Zahn, Dietrich R.T. [Semiconductor Physics, Chemnitz University of Technology, D-09107, Chemnitz (Germany)

    2013-09-30

    This work is devoted to the investigation of surface-enhanced Raman scattering by vibrational modes of cobalt phthalocyanine ultrathin films and CuS nanocrystals prepared using by organic molecular beam vapor deposition and the Langmuir–Blodgett technique, respectively, on laterally ordered arrays of Au nanoclusters formed by electron beam lithography on Si and GaAs substrates. The surface-enhanced Raman scattering study of cobalt phthalocyanine films demonstrates the strong dependence of Raman intensity of vibrational modes in cobalt phthalocyanine on the laser excitation wavelength as well as on the size and period of Au nanoclusters. By tuning the optical resonance conditions a maximal enhancement factor of 2 × 10{sup 4} is achieved. The investigation of surface-enhanced Raman scattering by cobalt phthalocyanine deposited on laterally ordered arrays of paired Au nanoclusters (dimers) reveals anisotropic enhancement with respect to polarization of the scattered light parallel or perpendicular to the dimer axis. - Highlights: • Controllable and reproducible Au nanocluster and dimer arrays were fabricated. • Surface enhanced Raman scattering (SERS) by CuS nanocrystals was observed. • SERS by ultrathin cobalt phthalocyanine (CoPc) films was observed. • Dependence of SERS enhancement factor on the size of Au nanoclusters is resonant. • SERS by ultrathin CoPc films formed on Au dimer arrays is polarization dependent.

  17. Quantitative analysis of a reinforcing fabric structure as a prerequisite for modelling the mechanical properties of composites

    Czech Academy of Sciences Publication Activity Database

    Košková, B.; Glogar, Petr; Černý, M.

    11(128) (2003), s. 11-17 ISSN 1212-1576 R&D Projects: GA ČR GA106/99/0096 Institutional research plan: CEZ:AV0Z3046908 Keywords : fabric reinforced composite * image analysis * spectral analysis Subject RIV: JI - Composite Materials

  18. One-step controllable fabrication of superhydrophobic surfaces with special composite structure on zinc substrates.

    Science.gov (United States)

    Ning, Tao; Xu, Wenguo; Lu, Shixiang

    2011-09-01

    Stable superhydrophobic platinum surfaces have been effectively fabricated on the zinc substrates through one-step replacement deposition process without further modification or any other post-treatment procedures. The fabrication process was controllable, which could be testified by various morphologies and hydrophobic properties of different prepared samples. By conducting SEM and water CA analysis, the effects of reaction conditions on the surface morphology and hydrophobicity of the resulting surfaces were carefully studied. The results show that the optimum condition of superhydrophobic surface fabrication depends largely on the positioning of zinc plate and the concentrations of reactants. When the zinc plate was placed vertically and the concentration of PtCl(4) solution was 5 mmol/L, the zinc substrate would be covered by a novel and interesting composite structure. The structure was composed by microscale hexagonal cavities, densely packed nanoparticles layer and top micro- and nanoscale flower-like structures, which exhibit great surface roughness and porosity contributing to the superhydrophobicity. The maximal CA value of about 171° was obtained under the same reaction condition. The XRD, XPS and EDX results indicate that crystallite pure platinum nanoparticles were aggregated on the zinc substrates in accordance with a free deposition way. Copyright © 2011 Elsevier Inc. All rights reserved.

  19. Characterization of fabricated three dimensional scaffolds of bio ceramic-polymer composite via microstereolithography technique

    International Nuclear Information System (INIS)

    Marina Talib; Covington, J.A.; Bolarinwa, A.

    2013-01-01

    Full-text: Microstereolithography is a method used for rapid proto typing of polymeric and ceramic components. This technique converts a computer-aided design (CAD) to a three dimensional (3D) model, and enables layer per layer fabrication curing a liquid resin with UV-light or laser source. The aim of this project was to formulate photo curable polymer reinforced with synthesized calcium pyrophosphate (CPP), and to fabricate a 3D scaffolds with optimum mechanical properties for specific tissue engineering applications. The photo curable ceramic suspension was prepared with acrylate polyester, multifunctional acrylate monomer with the addition of 50-70 wt % of CPP, photo initiators and photo inhibitors. The 3D structure of disc (5 mm height x 4 mm diameter) was successfully fabricated using Envisiontec Perfactory3. They were then sintered at high temperature for polymer removal, to obtain a ceramic of the desired porosity. The density increased to more than 35 % and the dimensional shrinkage after sintering were 33 %. The discs were then subjected compressive measurement, biodegradation and bioactivity test. Morphology and CPP content of the sintered polymer was investigated with SEM and XRD, respectively. The addition of CPP coupled with high temperature sintering, had a significant effect on the compressive strength exhibited by the bio ceramic. The values are in the range of cancellous bone (2-4 MPa). In biodegradation and bioactivity test, the synthesized CPP induced the formation of apatite layer and its nucleation onto the composite surface. (author)

  20. Characterization of fabricated three dimensional scaffolds of bioceramic-polymer composite via microstereolithography technique

    Science.gov (United States)

    Talib, Marina; Covington, James A.; Bolarinwa, Aminat

    2014-02-01

    Microstereolithography is a method used for rapid prototyping of polymeric and ceramic components. This technique converts a computer-aided design (CAD) to a three dimensional (3D) model, and enables layer per layer fabrication curing a liquid resin with UV-light or laser source. The aim of this project was to formulate photocurable polymer reinforced with synthesized calcium pyrophosphate (CPP), and to fabricate a 3D scaffolds with optimum mechanical properties for specific tissue engineering applications. The photocurable ceramic suspension was prepared with acrylate polyester, multifunctional acrylate monomer with the addition of 50-70wt% of CPP, photoinitiators and photoinhibitors. The 3D structure of disc (5 mm height × 4 mm diameter) was successfully fabricated using Envisiontec Perfactory3® . They were then sintered at high temperature for polymer removal, to obtain a ceramic of the desired porosity. The density increased to more than 35% and the dimensional shrinkage after sintering were 33%. The discs were then subjected compressive measurement, biodegradation and bioactivity test. Morphology and CPP content of the sintered polymer was investigated with SEM and XRD, respectively. The addition of CPP coupled with high temperature sintering, had a significant effect on the compressive strength exhibited by the bioceramic. The values are in the range of cancellous bone (2-4 MPa). In biodegradation and bioactivity test, the synthesized CPP induced the formation of apatite layer and its nucleation onto the composite surface.

  1. Fabrication and Testing of Durable Redundant and Fluted-Core Joints for Composite Sandwich Structures

    Science.gov (United States)

    Lin, Shih-Yung; Splinter, Scott C.; Tarkenton, Chris; Paddock, David A.; Smeltzer, Stanley S.; Ghose, Sayata; Guzman, Juan C.; Stukus, Donald J.; McCarville, Douglas A.

    2013-01-01

    The development of durable bonded joint technology for assembling composite structures is an essential component of future space technologies. While NASA is working toward providing an entirely new capability for human space exploration beyond low Earth orbit, the objective of this project is to design, fabricate, analyze, and test a NASA patented durable redundant joint (DRJ) and a NASA/Boeing co-designed fluted-core joint (FCJ). The potential applications include a wide range of sandwich structures for NASA's future launch vehicles. Three types of joints were studied -- splice joint (SJ, as baseline), DRJ, and FCJ. Tests included tension, after-impact tension, and compression. Teflon strips were used at the joint area to increase failure strength by shifting stress concentration to a less sensitive area. Test results were compared to those of pristine coupons fabricated utilizing the same methods. Tensile test results indicated that the DRJ design was stiffer, stronger, and more impact resistant than other designs. The drawbacks of the DRJ design were extra mass and complex fabrication processes. The FCJ was lighter than the DRJ but less impact resistant. With barely visible but detectable impact damages, all three joints showed no sign of tensile strength reduction. No compression test was conducted on any impact-damaged sample due to limited scope and resource. Failure modes and damage propagation were also studied to support progressive damage modeling of the SJ and the DRJ.

  2. Cellulose/inorganic-composite fibers for producing textile fabrics of high X-ray absorption properties

    Energy Technology Data Exchange (ETDEWEB)

    Günther, Karoline; Giebing, Christina; Askani, Antonia [FTB, Hochschule Niederrhein – University of Applied Science, Faculty of Textile and Clothing Technology, Webschulstr. 31, 41065 Mönchengladbach (Germany); Leisegang, Tilmann [Saxray GmbH, Maria-Reiche-Str. 1, 01109 Dresden (Germany); Krieg, Marcus [TITK, Thüringisches Institut für Textil- und Kunststoff-Forschung e.V., Breitscheidstraße 97, 07407 Rudolstadt (Germany); Kyosev, Yordan; Weide, Thomas [FTB, Hochschule Niederrhein – University of Applied Science, Faculty of Textile and Clothing Technology, Webschulstr. 31, 41065 Mönchengladbach (Germany); Mahltig, Boris, E-mail: Boris.Mahltig@hs-niederrhein.de [FTB, Hochschule Niederrhein – University of Applied Science, Faculty of Textile and Clothing Technology, Webschulstr. 31, 41065 Mönchengladbach (Germany)

    2015-11-01

    Common textile materials as cotton or polyester do not possess reliable X-ray absorption properties. This is due to their morphology and chemical composition in particular. Common fibers are built up from organic polymers containing mainly the elements carbon, hydrogen, oxygen and nitrogen. These “light” elements only have low X-ray absorption coefficients. In contrast, inorganic materials composed of “heavy” elements with high atomic numbers, e.g. barium or bismuth, exhibit X-ray absorption coefficients higher by up to two orders of magnitude. To obtain a flexible yarn with high X-ray absorption properties both these materials, the organic polymer and the inorganic X-ray absorber, are combined to an inorganic/organic composite fiber material. Hence, as the organic component cellulose from modified Lyocell-process is used as carrier fiber and blended with inorganic absorber particles of low toxicity and high absorption coefficients, as bariumsulphate, bariumtitanate or bismuthoxide. A content of inorganic absorber particles equally distributed in the whole fiber of up to 20% is achieved. The composite fibers are produced as staple or filament fibers and processed to multifilament or staple fiber yarns. The staple fiber yarns are rotor-spinned to increase the comfort of the subsequent textile material. Several woven fabrics, considering multilayer structure and different warp/weft density, are developed. The energy dependent X-ray shielding properties are determined in dependence on the different yarn compositions, yarn types and structural parameters of the woven fabrics. As a result, a production process of textile materials with comfortable and dedicated X-ray absorption properties is established. It offers a promising opportunity for manufacturing of specialized textiles, working clothes or uniforms applicable for medicine, air craft and security personal, mining as well as for innovative composite materials. - Highlights: • Preparation of cellulosic

  3. Transport behavior of n-alkane penetrants into castor oil based polyurethane-polyester nonwoven fabric composites

    International Nuclear Information System (INIS)

    Satheesh Kumar, M.N.; Manjula, K.S.; Siddaramaiah

    2007-01-01

    Castor oil based polyurethane (PU)-polyester nonwoven fabric composites were fabricated by impregnating the polyester nonwoven fabric in a composition containing castor oil and diisocyanate. Composites were fabricated with two different isocyanates such as toluene-2,4-diisocyanate (TDI) and hexamethylene diisocyanate (HMDI). Transport behavior of n-alkane penetrants (pentane, hexane and heptane) into both PUs and PU-polyester nonwoven fabric composites were studied. Sorption studies were carried out at different temperatures. From the sorption results, the diffusion (D) and permeation (P) coefficients of penetrants have been calculated. Significant increase in the diffusion and permeation coefficients was observed with increase in the temperature of sorption experiments. Drastical reduction in diffusion and permeation coefficients was noticed in the composites compared to neat PUs. Attempts were made to estimate the empirical parameters like n, which suggests the mode of transport and K is a constant depends on the structural characteristics of the composite in addition to its interaction with penetrants. The temperature dependence of the transport coefficients has been used to estimate the activation energy parameter for diffusion (E D ) and permeation (E P ) processes from Arrhenius plots. Furthermore, the sorption results have been interpreted in terms of the thermodynamic parameters such as enthalpy (ΔH) and entropy (ΔS)

  4. NiCoCrAl/YSZ laminate composites fabricated by EB-PVD

    International Nuclear Information System (INIS)

    Shi Guodong; Wang Zhi; Liang Jun; Wu Zhanjun

    2011-01-01

    Highlights: → The metal-ceramic laminate composites were fabricated by EB-PVD. → Both metal and ceramic layers consisted of straight columns with banded structures. → Columnar grain size was limited by the periodic layer interfaces in the laminates. → Effect of columns on fracture property was decreased by limiting layer thickness. → Laminates showed greater specific strength than monolithic metal foil. - Abstract: Two NiCoCrAl/YSZ laminate composites (A and B) with different metal-layer thickness (∼35 μm and 14 μm, respectively) were fabricated by electron beam physical vapor deposition (EB-PVD). Their microstructure was examined and their mechanical properties were compared with the 289 μm thick NiCoCrAl monolithic foil produced by EB-PVD. Both the YSZ and NiCoCrAl layers of the laminate composites had columnar grain structure. But the periodic layer interfaces limited the columnar grain size. Some pores between the columns were also observed. It was found that the strength of the laminate A was equal approximately to that of the NiCoCrAl monolithic foil, and that laminate B had the greater strength. Moreover, the density of the foils decreased with the increasing thickness ratio of YSZ/NiCoCrAl layers and the increasing the layer number. Thus, comparing with the NiCoCrAl monolithic foil, the NiCoCrAl/YSZ laminate composites not only had the equal or greater strength, but also had the much greater specific strength.

  5. An analytical and experimental investigation of high-speed mechanisms fabricated with composite laminates

    Science.gov (United States)

    Thompson, B. S.; Sung, C. K.

    1986-12-01

    The articulating members of linkage machinery must be designed and manufactured with high stiffness-to-weight ratios in order that these machine systems operate successfully in a high-speed mode. One approach to satisfying this criterion is to exploit the high specific stiffnesses of polymeric fibrous composite laminates. In this paper, results of mechanical tests of candidate materials are presented and the material constitutive behaviour classified. A variational theorem is then derived by using the Stieltjes convolution notation which enables the equations governing the geometrically-non-linear dynamic response of linkages fabricated in linear viscoelastic composite materials to be systematically established. The formulation includes inertial terms which couple the kinematic deformations of the link material with the kinematics governing the gross motion of the linkage being analyzed. This variational principle provides the basis for a finite element formulation in which the properties of the heterogeneous, two-constituent laminates are represented by a continuum model for a homogeneous single-constituent material. The predictive capability of this model is evaluated by simulating the vibrational response of both experimental four-bar linkages and also slider-crank mechanisms fabricated with simple link geometries, prior to comparing the computer results with experimental data from these laboratory mechanisms.

  6. Tribology of Polymer Matrix Composites (PMCs) Fabricated by Additive Manufacturing (AM)

    Science.gov (United States)

    Gupta, S.; Dunnigan, R.; Salem, A.; Kuentz, L.; Halbig, M. C.; Singh, M.

    2016-01-01

    The integral process of depositing thin layers of material, one after another, until the designed component is created is collectively referred to as Additive Manufacturing (AM). Fused deposition process (FDP) is a type of AM where feedstock is extruded into filaments which then are deposited by 3D printing, and the solidification occurs during cooling of the melt. Currently, complex structures are being fabricated by commercial and open source desktop 3D printers. Recently, metal powder containing composite filaments based on polylactic acid (PLA) and acrylonitrile butadiene styrene (ABS) have emerged, which could be utilized for multifunctional applications. For further deployment in the field, especially for aerospace and ground-based applications, it is critical to understand the tribological behavior of 3D printed materials. In this presentation, we will report the tribological behavior of different polymer matrix composites fabricated by fused deposition process. These results will be compared with the base polymer systems. During this study, the tribological behavior of all the samples will be evaluated with tab-on-disc method and compared for different metallic powder reinforcements.

  7. Fabrication of block copolymer templated mesoporous metal oxide composites for energy storage applications

    Science.gov (United States)

    Bhaway, Sarang M.

    Block copolymer templated mesoporous (2 nm-50 nm) metal oxides are considered promising electrode materials for energy storage devices such as electrochemical capacitors or lithium/sodium ion batteries. The mesoporous electrode morphology offers several advantages: (1) high surface area and porosity facilitate charge transfer across the electrolyte-electrode interface, (2) nanoscale-dimension of the oxide framework minimizes the solid state ion diffusion paths, and (3) interconnected porous morphology enables rapid electrolyte transport through the electrodes, leading to overall enhancement in charge storage capabilities. This research attempts to study the effect of mesoporosity and mesopore geometry on charge storage capabilities and cycling stability of ordered mesoporous metal oxide electrodes in energy storage devices. The first part of this dissertation focuses on fabrication of ordered mesoporous metal oxide composites utilizing the Evaporation Induced Self-Assembly (EISA) and the Block Copolymer Micelle Templating (BCMT) strategy. Firstly, we demonstrate fabrication of ordered mesoporous carbon-vanadium oxide composites utilizing EISA of phenolic resin oligomer (resol), VOCl3 and an amphiphilic triblock. We illustrate that carbon yield from resol carbonization can prevent break-out crystallization of vanadia during calcination and help maintain an ordered mesostructure. The mesoporous carbon-vanadia mesostructured thin films exhibit specific capacitance 7 times higher than their non-porous analog at high scan rates when tested as electrode in aqueous supercapacitor. The second part of this thesis focuses on BCMT technique to fabricate ordered mesoporous mixed-metal oxide electrodes for battery applications. Ordered mesoporous NixCo(3-x)O4 thin films with varying chemical composition are fabricated using a metal nitrate-citric acid complex and an amphiphilic PEGMA-b-PBA block copolymer template. This templating strategy is further extended to fabricate

  8. Fabrication and characterisation of composites materials similar optically and in composition to native dental tissues

    Science.gov (United States)

    Seredin, P. V.; Goloshchapov, D. L.; Prutskij, T.; Ippolitov, Yu. A.

    This study investigated the luminescence characteristics of synthesized biocomposites similar in organic and mineral composition to native dental tissues, enamel and dentine. It was found that the luminescence spectrum of intact enamel is similar to that of calcium hydroxyapatite (HAP) used to synthesize biomimetic materials. Despite the morphological differences between the synthesized biocomposite and native tissue, their luminescence spectra suggest that the shape of the luminescence spectrum is more influenced by defects in the crystal structure of the employed hydroxyapatite than by the structure and order of the apatite nanocrystals typical of native dental tissues. The spectrum of intact human dentine possessed a wider luminescence band, unlike that of enamel, with a maximum typical of intact dentine. Analysis of the spectra of biomimetic material modelling the properties of dentine indicated that both the organic and non-organic components contribute to their luminescence.

  9. Fabrication and characterisation of composites materials similar optically and in composition to native dental tissues

    Directory of Open Access Journals (Sweden)

    P.V. Seredin

    Full Text Available This study investigated the luminescence characteristics of synthesized biocomposites similar in organic and mineral composition to native dental tissues, enamel and dentine. It was found that the luminescence spectrum of intact enamel is similar to that of calcium hydroxyapatite (HAP used to synthesize biomimetic materials. Despite the morphological differences between the synthesized biocomposite and native tissue, their luminescence spectra suggest that the shape of the luminescence spectrum is more influenced by defects in the crystal structure of the employed hydroxyapatite than by the structure and order of the apatite nanocrystals typical of native dental tissues. The spectrum of intact human dentine possessed a wider luminescence band, unlike that of enamel, with a maximum typical of intact dentine. Analysis of the spectra of biomimetic material modelling the properties of dentine indicated that both the organic and non-organic components contribute to their luminescence.

  10. Fabrication and characterization of Ni–Zr composite coatings using electrodepositing technique

    International Nuclear Information System (INIS)

    Cai, Fei; Jiang, Chuanhai; Zhang, Zhongquan; Muttini, Enzo; Fu, Peng; Zhao, Yuantao; Ji, Vincent

    2015-01-01

    Highlights: • A novel Ni–Zr coatings with higher Zr content were fabricated. • Increasing Zr content resulted in the (1 1 1) preferred orientation. • The (1 1 1) preferred orientation increased the corrosion resistance. • Relationship between corrosion and Zr content, grain and texture was discussed. - Abstract: The main goal of this research is to prepare Ni–Zr composite coatings with different amounts of Zr micro-particles by using electrodeposition technology. Different characterization techniques including X-ray diffractometer (XRD), field emission scanning electron microscopy (FESEM) and Energy Dispersive X-ray Spectroscopy (EDX) were used to investigate the effects of Zr micro-particle contents on the surface morphology, texture, grain size, residual stress and hardness of the Ni–Zr composite coatings. The electrochemical impedance and potentiodynamic polarization measurements were also used to examine the corrosion resistance. As the Zr contents in the Ni–Zr composite coating increased, the (2 0 0) texture changed to the (1 1 1) texture, the grain size decreased, the residual stress and hardness increased. The anti-corrosion properties of the Ni–Zr composite coatings could be linked to several reasons such as the amount of Zr micro-particles in the deposits, a decrease in grain size, and a change in the texture of the deposits

  11. Fabrication and characterization of polymer blends and composites derived from biopolymers

    Science.gov (United States)

    Sharma, Suraj

    This research focuses on fabricating blends and composites from natural polymers especially from proteins and natural epoxy, and describing the properties of plastics made from them. Specifically, plastic samples from partially denatured feathermeal and bloodmeal proteins, derived from the animal co-products (rendering) industry, were successfully produced through a compression molding process. The modulus (stiffness) of the material obtained was found to be comparable with that of commercial synthetic materials, such as polystyrene, but was found to have lower toughness characteristics, which is a common phenomenon among plastics produced from animal and plant proteins. Therefore, this study explored blending methods for improving the toughness. Plastic forming conditions for undenatured animal proteins such as chicken egg whites albumin and whey, used as a model, were established to prepare plastics from their blends with animal co-product proteins. The resultant plastic samples from these biomacromolecular blends demonstrated improved mechanical properties that were also compared with the established theoretical models known for polymer blends and composites. Moreover, plastics from albumin of chicken egg whites and human serum have demonstrated their potential in medical applications that require antibacterial properties. Another natural polymer vegetable oil-based epoxy, especially epoxidized linseed oil, showed significant potential to replace petroleum-derived resins for use as a matrix for composites in structural applications. Moreover, the research showed the benefits of ultrasonic curing, which can help in preparing the out-of-autoclave composites.

  12. Fabrication and electromagnetic interference shielding effectiveness of polymeric composites filled with silver-coated microorganism cells

    Energy Technology Data Exchange (ETDEWEB)

    Lan, Mingming, E-mail: lan_mingming@163.com [College of Mechanical and Electrical Engineering, Henan Agricultural University, Zhengzhou 450002 (China); Zhang, Deyuan; Cai, Jun; Hu, Yanyan; Yuan, Liming [Bionic and Micro/Nano/Bio Manufacturing Technology Research Center, School of Mechanical Engineering and Automation, Beihang University, Beijing 100191 (China)

    2014-07-01

    In this paper, helical silver-coated Spirulina cells were used as conductive fillers for the fabrication of polymeric composites. The morphology and composition of the coated Spirulina cells were analyzed with scanning electron microscope and energy dispersive X-ray spectrometer. The densities of silver-coated Spirulina cells were measured using the standard Archimedes method with distilled water. The electrical resistivity was measured by four-probe technique using ammeter and voltmeter whereas electromagnetic interference shielding effectiveness was measured by four-port method using vector network analyzer and coaxial-airline sample holder. The results showed that the silver-coated Spirulina cells with different coating thickness were lightweight fillers compared to the other typical conductive particles. The polymeric composites could achieve good conductivity at the lower content of silver-coated Spirulina cells owing to their helical shape. The shielding effectiveness of polymeric composites had a strong dependence on their conductivity. At the coating thickness of 0.96 μm and the content of 40 vol%, the shielding effectiveness could reach above 74.3 dB in entire test wave band.

  13. Planar Porous Graphene Woven Fabric/Epoxy Composites with Exceptional Electrical, Mechanical Properties, and Fracture Toughness.

    Science.gov (United States)

    Liu, Xu; Sun, Xinying; Wang, Zhenyu; Shen, Xi; Wu, Ying; Kim, Jang-Kyo

    2015-09-30

    Planar interconnected graphene woven fabrics (GWFs) are prepared by template-based chemical vapor deposition and the GWFs are employed as multifunctional filler for epoxy-based composites. Apart from flexibility, transparency, lightweight, and high electrical conductivity, the GWFs have unique morphological features consisting of orthogonally interweaved, inherently percolated, hollow graphene tubes (GTs). The orthogonal GT structure means that the GWF/epoxy composites hold significant anisotropy in mechanical and fracture properties. The composites with 0.62 wt % graphene deliver a combination of excellent electrical and fracture properties: e.g., an electrical conductivity of ~0.18 S/cm; and fracture toughness of 1.67 and 1.78 MPa·m(1/2) when loaded along the 0° and 45° directions relative to the GT direction, respectively, equivalent to notable 57% and 67% rises compared to the solid epoxy. Unique fracture processes in GWF/epoxy composites are identified by in situ examinations, revealing crack tip blunting that occurs when the crack impinges GTs, especially those at 45° to the crack growth direction, as well as longitudinal tearing of hollow GTs as the two major toughening mechanisms.

  14. Fabrication of Surface Level Cu/Si Cp Nano composites by Friction Stir Processing Route

    International Nuclear Information System (INIS)

    Srinivasan, R. C.; Karunanithi, M.

    2015-01-01

    Friction stir processing (FSP) technique has been successfully employed as low energy consumption route to prepare copper based surface level nano composites reinforced with nano sized silicon carbide particles (Si Cp). The effect of FSP parameters such as tool rotational speed, processing speed, and tool tilt angle on microstructure and microhardness was investigated. Single pass FSP was performed based on Box-Behnken design at three factors in three levels. A cluster of blind holes 2 mm in diameter and 3 mm in depth was used as particulate deposition technique in order to reduce the agglomeration problem during composite fabrication. K-type thermocouples were used to measure temperature histories during FSP. The results suggest that the heat generation during FSP plays a significant role in deciding the microstructure and microhardness of the surface composites. Microstructural observations revealed a uniform dispersion of nano sized Si Cp without any agglomeration problem and well bonded with copper matrix at different process parameter combinations. X-ray diffraction study shows that no intermetallic compound was produced after processing. The microhardness of nano composites was remarkably enhanced and about 95% more than that of copper matrix

  15. Effects of mechanical properties of polymer on ceramic-polymer composite thick films fabricated by aerosol deposition

    OpenAIRE

    Kwon, Oh-Yun; Na, Hyun-Jun; Kim, Hyung-Jun; Lee, Dong-Won; Nam, Song-Min

    2012-01-01

    Two types of ceramic-polymer composite thick films were deposited on Cu substrates by an aerosol deposition process, and their properties were investigated to fabricate optimized ceramic-based polymer composite thick films for application onto integrated substrates with the advantage of plasticity. When polymers with different mechanical properties, such as polyimide (PI) and poly(methyl methacrylate) (PMMA), are used as starting powders together with α-Al2O3 powder, two types of composite fi...

  16. Biochar composite membrane for high performance pollutant management: Fabrication, structural characteristics and synergistic mechanisms.

    Science.gov (United States)

    Ghaffar, Abdul; Zhu, Xiaoying; Chen, Baoliang

    2018-02-01

    Biochar, a natural sourced carbon-rich material, has been used commonly in particle shape for carbon sequestration, soil fertility and environmental remediation. Here, we report a facile approach to fabricate freestanding biochar composite membranes for the first time. Wood biochars pyrolyzed at 300 °C and 700 °C were blended with polyvinylidene fluoride (PVdF) in three percentages (10%, 30% and 50%) to construct membranes through thermal phase inversion process. The resultant biochar composite membranes possess high mechanical strength and porous structure with uniform distribution of biochar particles throughout the membrane surface and cross-section. The membrane pure water flux was increased with B300 content (4825-5411 ± 21 L m -2 h -1 ) and B700 content (5823-6895 ± 72 L m -2 h -1 ). The membranes with B300 were more hydrophilic with higher surface free energy (58.84-60.31 mJ m -2 ) in comparison to B700 (56.32-51.91 mJ m -2 ). The biochar composite membranes indicated promising adsorption capacities (47-187 mg g -1 ) to Rhodamine B (RhB) dye. The biochar membranes also exhibited high retention (74-93%) for E. coli bacterial suspensions through filtration. After simple physical cleaning, both the adsorption and sieving capabilities of the biochar composite membranes could be effectively recovered. Synergistic mechanisms of biochar/PVdF in the composite membrane are proposed to elucidate the high performance of the membrane in pollutant management. The multifunctional biochar composite membrane not only effectively prevent the problems caused by directly using biochar particle as sorbent but also can be produced in large scale, indicating great potential for practical applications. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Fabrication and properties of polyimide composites filled with zirconium tungsten phosphate of negative thermal expansion

    Energy Technology Data Exchange (ETDEWEB)

    Shi, XinWei, E-mail: Shixw@zzu.edu.cn [School of Physical Science & Engineering, Zhengzhou University, 100th Science Road, Zhengzhou 450001 (China); Lian, Hong; Yan, XiaoSheng; Qi, Ruiqiong; Yao, Ning [School of Physical Science & Engineering, Zhengzhou University, 100th Science Road, Zhengzhou 450001 (China); Li, Tao [Department of Technology & Physics, Zhengzhou University of Lightindustry, 5th Dongfeng Road, Zhengzhou 450002 (China)

    2016-08-15

    Negative thermal expansion Zr{sub 2}WP{sub 2}O{sub 12} (ZWP) powder prepared by hydrothermal method was used as fillers to tailor the thermal expansion coefficient (TEC) of the polyimide (PI)-based composites. A series of PI-based composites containing different loading (0–40 wt% or 0–19.6 vol%) of ZWP powder were fabricated by the in-situ polymerization technique. Their structures and properties were characterized by Scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), Impedance meter, Thermal mechanical analysis (TMA) and Thermogravimetric analysis (TGA). The additions of ZWP steadily reduced the TEC of the PI matrix at all loadings studied. A 40 wt% (19.6 vol%) ZWP loading gives a 32.5% (about 15 × 10{sup −6}/K) reduction of TEC. The thermal stability of the ZWP/PI composites can be enhanced with the increment of ZWP powder. The independence of the dielectric constant on frequency is improved by introduction of ZWP particles to PIs. The dielectric loss displays good stability, which indicates that the ZWP/PI composites show potential applications in microelectronic and aerospace industries. - Graphical abstract: With increasing of ZWP in the composites, the CTEs of the ZWP/PI were reduced. A 40 wt% (19.6 vol%) ZWP loading gives a 32.5% (about 15 × 10{sup −6}/K) reduction of CTE of the composite. - Highlights: • Zr{sub 2}P{sub 2}WO{sub 12} was firstly used as filler to tune the TEC of polyimides. • The TECs of polyimides were reduced by introduction of Zr{sub 2}P{sub 2}WO{sub 12} powders. • Polyimides with reduced TECs have favorable thermal and dielectric properties.

  18. Fabrication of functionally gradient materials with internal channels in ceramics and ceramic composites

    Science.gov (United States)

    Shin, Hyea-Weon

    Functionally Gradient Materials (FGMs) are inhomogeneous materials whose compositions vary from one phase to another. By tailoring the inhomogeneous properties, FGMs can be used to reduce the stresses that are caused by severe thermal gradients. Thermal gradient loading can further be compensated by heat transfer into a cooling fluid circulating in a network of channels and manifolds. In an envisioned application, heat from a localized source is transferred to the cooling fluid, easing sharp thermal loads while minimizing the unwanted spread of heat energy to the ambient surroundings. This study reports on the fabrication of functionally gradient ceramics and the embedding of simple internal channels within these ceramics. Functional gradiency (variation of composition) is built in via the layering of different components across the thickness of a plate sample. Traditional powder processing techniques are applied to fabricate the test pieces, and recently developed methods of joining are used to build assemblies from individually sintered plate layers. For a well-formed FGM to be made, materials parameters need to be selected based on mechanical, thermal and chemical properties. As a class, ceramics are hard, wear-resistant, refractory, electrically and thermally insulative, nonmagnetic, chemically stable, and oxidation-resistant. However, because of their brittleness, ceramics with minute channels are difficult to machine. Instead, for this study, a graphite fugitive phase is used as a spacer to support channel volumes within a ceramic powder compact; during pre-sintering, the graphite burns out to expose a network of channels. Full sintering fixes the final shape. At the operating temperatures of the ovens used in our fabrication study, sintering of alumina, partially stabilized zirconia, fully stabilized zirconia and hydroxyapatite have been successful, and these ceramic powders form the basis of the present fabrication studies. Inhomogeneities inherent in the

  19. Fabrication, testing, and analysis of anisotropic carbon/glass hybrid composites: volume 1: technical report.

    Energy Technology Data Exchange (ETDEWEB)

    Wetzel, Kyle K. (Wetzel Engineering, Inc. Lawrence, Kansas); Hermann, Thomas M. (Wichita state University, Wichita, Kansas); Locke, James (Wichita state University, Wichita, Kansas)

    2005-11-01

    Anisotropic carbon/glass hybrid composite laminates have been fabricated, tested, and analyzed. The laminates have been fabricated using vacuum-assisted resin transfer molding (VARTM). Five fiber complexes and a two-part epoxy resin system have been used in the study to fabricate panels of twenty different laminate constructions. These panels have been subjected to physical testing to measure density, fiber volume fraction, and void fraction. Coupons machined from these panels have also been subjected to mechanical testing to measure elastic properties and strength of the laminates using tensile, compressive, transverse tensile, and in-plane shear tests. Interlaminar shear strength has also been measured. Out-of-plane displacement, axial strain, transverse strain, and inplane shear strain have also been measured using photogrammetry data obtained during edgewise compression tests. The test data have been reduced to characterize the elastic properties and strength of the laminates. Constraints imposed by test fixtures might be expected to affect measurements of the moduli of anisotropic materials; classical lamination theory has been used to assess the magnitude of such effects and correct the experimental data for the same. The tensile moduli generally correlate well with experiment without correction and indicate that factors other than end constraints dominate. The results suggest that shear moduli of the anisotropic materials are affected by end constraints. Classical lamination theory has also been used to characterize the level of extension-shear coupling in the anisotropic laminates. Three factors affecting the coupling have been examined: the volume fraction of unbalanced off-axis layers, the angle of the off-axis layers, and the composition of the fibers (i.e., carbon or glass) used as the axial reinforcement. The results indicate that extension/shear coupling is maximized with the least loss in axial tensile stiffness by using carbon fibers oriented 15{sup

  20. Metal Catalysts for Heterogeneous Catalysis: From Single Atoms to Nanoclusters and Nanoparticles.

    Science.gov (United States)

    Liu, Lichen; Corma, Avelino

    2018-04-16

    Metal species with different size (single atoms, nanoclusters, and nanoparticles) show different catalytic behavior for various heterogeneous catalytic reactions. It has been shown in the literature that many factors including the particle size, shape, chemical composition, metal-support interaction, and metal-reactant/solvent interaction can have significant influences on the catalytic properties of metal catalysts. The recent developments of well-controlled synthesis methodologies and advanced characterization tools allow one to correlate the relationships at the molecular level. In this Review, the electronic and geometric structures of single atoms, nanoclusters, and nanoparticles will be discussed. Furthermore, we will summarize the catalytic applications of single atoms, nanoclusters, and nanoparticles for different types of reactions, including CO oxidation, selective oxidation, selective hydrogenation, organic reactions, electrocatalytic, and photocatalytic reactions. We will compare the results obtained from different systems and try to give a picture on how different types of metal species work in different reactions and give perspectives on the future directions toward better understanding of the catalytic behavior of different metal entities (single atoms, nanoclusters, and nanoparticles) in a unifying manner.

  1. Facile Fabrication of 100% Bio-based and Degradable Ternary Cellulose/PHBV/PLA Composites

    Directory of Open Access Journals (Sweden)

    Tao Qiang

    2018-02-01

    Full Text Available Modifying bio-based degradable polymers such as polylactide (PLA and poly(hydroxybutyrate-co-hydroxyvalerate (PHBV with non-degradable agents will compromise the 100% degradability of their resultant composites. This work developed a facile and solvent-free route in order to fabricate 100% bio-based and degradable ternary cellulose/PHBV/PLA composite materials. The effects of ball milling on the physicochemical properties of pulp cellulose fibers, and the ball-milled cellulose particles on the morphology and mechanical properties of PHBV/PLA blends, were investigated experimentally and statistically. The results showed that more ball-milling time resulted in a smaller particle size and lower crystallinity by way of mechanical disintegration. Filling PHBV/PLA blends with the ball-milled celluloses dramatically increased the stiffness at all of the levels of particle size and filling content, and improved their elongation at the break and fracture work at certain levels of particle size and filling content. It was also found that the high filling content of the ball-milled cellulose particles was detrimental to the mechanical properties for the resultant composite materials. The ternary cellulose/PHBV/PLA composite materials have some potential applications, such as in packaging materials and automobile inner decoration parts. Furthermore, filling content contributes more to the variations of their mechanical properties than particle size does. Statistical analysis combined with experimental tests provide a new pathway to quantitatively evaluate the effects of multiple variables on a specific property, and figure out the dominant one for the resultant composite materials.

  2. Designing of epoxy composites reinforced with carbon nanotubes grown carbon fiber fabric for improved electromagnetic interference shielding

    Directory of Open Access Journals (Sweden)

    B. P. Singh

    2012-06-01

    Full Text Available In this letter, we report preparation of strongly anchored multiwall carbon nanotubes (MWCNTs carbon fiber (CF fabric preforms. These preforms were reinforced in epoxy resin to make multi scale composites for microwave absorption in the X-band (8.2-12.4GHz. The incorporation of MWCNTs on the carbon fabric produced a significant enhancement in the electromagnetic interference shielding effectiveness (EMI-SE from −29.4 dB for CF/epoxy-composite to −51.1 dB for CF-MWCNT/epoxy multiscale composites of 2 mm thickness. In addition to enhanced EMI-SE, interlaminar shear strength improved from 23 MPa for CF/epoxy-composites to 50 MPa for multiscale composites indicating their usefulness for making structurally strong microwave shields.

  3. Fabrication of Wood-Rubber Composites Using Rubber Compound as a Bonding Agent Instead of Adhesives

    Directory of Open Access Journals (Sweden)

    Dongwei Shao

    2016-06-01

    Full Text Available Differing from the hot-pressing method in the manufacturing of traditional wood-rubber composites (WRCs, this study was aimed at fabricating WRCs using rubber processing to improve water resistance and mechanical properties. Three steps were used to make WRCs, namely, fiber-rubber mixing, tabletting, and the vulcanization molding process. Ninety-six WRC panels were made with wood fiber contents of 0%–50% at rotor rotational speeds of 15–45 rpm and filled coefficients of 0.55–0.75. Four regression equations, i.e., the tensile strength (Ts, elongation at break (Eb, hardness (Ha and rebound resilience (Rr as functions of fiber contents, rotational speed and filled coefficient, were derived and a nonlinear programming model were developed to obtain the optimum composite properties. Although the Ts, Eb and Rr of the panels were reduced, Ha was considerably increased by 17%–58% because of the wood fiber addition. Scanning electron microscope images indicated that fibers were well embedded in rubber matrix. The 24 h water absorption was only 1%–3%, which was much lower than commercial wood-based composites.

  4. Fabrication of Wood-Rubber Composites Using Rubber Compound as a Bonding Agent Instead of Adhesives.

    Science.gov (United States)

    Shao, Dongwei; Xu, Min; Cai, Liping; Shi, Sheldon Q

    2016-06-14

    Differing from the hot-pressing method in the manufacturing of traditional wood-rubber composites (WRCs), this study was aimed at fabricating WRCs using rubber processing to improve water resistance and mechanical properties. Three steps were used to make WRCs, namely, fiber-rubber mixing, tabletting, and the vulcanization molding process. Ninety-six WRC panels were made with wood fiber contents of 0%-50% at rotor rotational speeds of 15-45 rpm and filled coefficients of 0.55-0.75. Four regression equations, i.e. , the tensile strength ( T s), elongation at break ( E b), hardness ( H a) and rebound resilience ( R r) as functions of fiber contents, rotational speed and filled coefficient, were derived and a nonlinear programming model were developed to obtain the optimum composite properties. Although the T s, E b and R r of the panels were reduced, H a was considerably increased by 17%-58% because of the wood fiber addition. Scanning electron microscope images indicated that fibers were well embedded in rubber matrix. The 24 h water absorption was only 1%-3%, which was much lower than commercial wood-based composites.

  5. Design and Fabrication of a Composite Morphing Radiator Panel Using High Conductivity Fibers

    Science.gov (United States)

    Wescott, Matthew T.; McQuien, J. Scott; Bertagne, Christopher L.; Whitcomb, John D.; Hart, Darren J.; Erickson, Lisa R.

    2017-01-01

    Upcoming crewed space missions will involve large internal and external heat loads and require advanced thermal control systems to maintain a desired internal environment temperature. Radiators with at least 12:1 turndown ratios (the ratio between the maximum and minimum heat rejection rates) will be needed. However, current technologies are only able to achieve turndown ratios of approximately 3:1. A morphing radiator capable of altering shape could significantly increase turndown capabilities. Shape memory alloys offer qualities that may be well suited for this endeavor; their temperature-dependent phase changes could offer radiators the ability to passively control heat rejection. In 2015, a morphing radiator prototype was constructed and tested in a thermal vacuum environment, where it successfully demonstrated the morphing behavior and variable heat rejection. Newer composite prototypes have since been designed and manufactured using two distinct types of SMA materials. These models underwent temperature cycling tests in a thermal vacuum chamber and a series of fatigue tests to characterize the lifespan of these designs. The focus of this paper is to present the design approach and testing of the morphing composite facesheet. The discussion includes: an overall description of the project background, definition of performance requirements, composite materials selection, use of analytic and numerical design tools, facesheet fabrication, and finally fatigue testing with accompanying results.

  6. Large-scale fabrication and utilization of novel hexagonal/turbostratic composite boron nitride nanosheets

    KAUST Repository

    Zhong, Bo

    2017-02-15

    In this report, we have developed a scalable approach to massive synthesis of hexagonal/turbostratic composite boron nitride nanosheets (h/t-BNNSs). The strikingly effective, reliable, and high-throughput (grams) synthesis is performed via a facile chemical foaming process at 1400°C utilizing ammonia borane (AB) as precursor. The characterization results demonstrate that high quality of h/t-BNNSs with lateral size of tens of micrometers and thickness of tens of nanometers are obtained. The growth mechanism of h/t-BNNSs is also discussed based on the thermogravimetric analysis of AB which clearly shows two step weight loss. The h/t-BNNSs are further used for making thermoconductive h/t-BNNSs/epoxy resin composites. The thermal conductivity of the composites is obviously improved due to the introduction of h/t-BNNSs. Consideration of the unique properties of boron nitride, these novel h/t-BNNSs are envisaged to be very valuable for future high performance polymer based material fabrication.

  7. Fabrication and Dielectric Properties of AlN Filled Epoxy Nano-composites

    Energy Technology Data Exchange (ETDEWEB)

    Gao Naiui; Yu Xin; Jin Haiyun; He Bo; Dong Pu [State Key Laboratory of Electrical Insulation and Power Equipment, Xi' an Jiaotong University, Xi' an, 710049 (China); Gao Chao, E-mail: hyjin@mail.xjtu.edu.cn

    2011-10-29

    Epoxy resins were materials with excellent mechanical, electrical properties and good chemical stability. Thus, they had been used in various fields, especially in electrical and electronic application. However, because they were brittle material, the fields of application were limited. Adding nano-Aluminum Nitride (AlN) into Epoxy resins could improve the toughness of the composites, the thermal behaviors of composites could also be improved, but the influence on dielectric properties was not very clear. In this research, epoxy resin based composites were fabricated. The relationships between the dielectric properties and the nano-AlN particle content were investigated. The results showed that, both relative permittivity ({epsilon}{sub r}) and dielectric loss tangent (tan{delta}) decreased to be less than that of monolithic epoxy when nano-AlN particle content was no more than certain amount, the DC volume resistivity ({rho}{sub v}) and low frequency resistivity decreased with increasing nano-AlN content (in certain range of content). AC breakdown strength (E{sub B}) did not have an obvious tendency with nano-AlN content.

  8. Fabrication and Crystal Structure of Sol-Gel Deposited BST Thin Films with Compositional Gradient

    Directory of Open Access Journals (Sweden)

    Czekaj D.

    2017-06-01

    Full Text Available In the present research technology of compositionally graded barium strontium titanate Ba1-xSrxTiO3 thin films deposited on stainless steel substrates by sol-gel spin coating followed with thermal annealing at T = 650°C is reported. Results of thermal behavior of the sol-gel derived powders with compositions used for fabrication of graded structure (i.e. with Sr mole fraction x = 0.5, 0.4 and 0.3 are described. X-ray diffraction studies of the phase composition and crystal structure of such complex thin film configuration are given. It was found that gel powders exhibited a large total weight loss of about Δm ≈ 44-47%. Three stages of weight loss took place at temperature ranges: below T ≈ 300°C, at ΔT ≈ 300-500°C and between T = 600°C and T = 800°C. Phase analysis has shown that the dominating phase is Ba0.67Sr0.33TiO3 compound while the second phase is Ba0.7Sr0.3TiO3 or Ba0.5Sr0.5TiO3 for “up-graded” and “down-graded” structure, respectively.

  9. Fabrication of superhydrophobic coating for preventing microleakage in a dental composite restoration.

    Science.gov (United States)

    Cao, Danfeng; Zhang, Yingchao; Li, Yao; Shi, Xiaoyu; Gong, Haihuan; Feng, Dan; Guo, Xiaowei; Shi, Zuosen; Zhu, Song; Cui, Zhanchen

    2017-09-01

    Superhydrophobic coatings were successfully fabricated by photo-crosslinked polyurethane (PU) and organic fluoro group-functionalized SiO 2 nanoparticles (F-SiO 2 NPs), and were introduced for preventing microleakage in a dental composite restoration. The F-SiO 2 NPs possessed low surface energy and the PU can not only improve the mechanical stability but also promote F-SiO 2 NPs to form multiscale structure, which could facilitate the properties of the as-prepared superhydrophobic coating by synergetic effect. The morphology and properties of the resulted superhydrophobic coatings with different PU/F-SiO 2 ratios were studied using 1 H NMR spectrum, fourier transform infrared spectra, scanning electron microscopy, atomic force microscopy and UV-vis spectrophotometry. The results showed that the superhydrophobic coatings with low PU/F-SiO 2 ratio (1:3) possessed excellent hierarchical papillae structure with trapped air pockets, high contact angle (160.1°), low sliding angle (superhydrophobic property, the as-prepared superhydrophobic coatings effectively prevented water permeation in resin composite restoration evaluation. This research may provide an effective method to solve the problem of microleakage and will efficiently increase the success rate of dental composite restorations. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Comprehensive mechanical characterization of PLA fabric combined with PCL to form a composite structure vascular graft.

    Science.gov (United States)

    Li, Chaojing; Wang, Fujun; Douglas, Graeham; Zhang, Ze; Guidoin, Robert; Wang, Lu

    2017-05-01

    Vascular grafts made by tissue engineering processes are prone to buckling and twisting, which can impede blood flow and lead to collapse of the vessel. These vascular conduits may suffer not only from insufficient tensile strength, but also from vulnerabilities related to compression, torsion, and pulsatile pressurization. Aiming to develop a tissue engineering-inspired blood conduit, composite vascular graft (cVG) prototypes were created by combining a flexible polylactic acid (PLA) knitted fabric with a soft polycaprolactone (PCL) matrix. The graft is to be populated in-situ with cellular migration and proliferation into the device. Comprehensive characterizations probed the relationship between structure and mechanical properties of the different cVG prototypes. The composite grafts exhibited major improvements in mechanical characteristics compared to single-material devices, with particular improvement in compression and torsional resistance. A commercial expanded polytetrafluoroethylene (ePTFE) vascular graft was used as a control against the proposed composite vascular grafts. CVG devices showed high tensile strength, high bursting strength, and improved suture retention. Compression, elastic recovery, and compliance were similar to those for the ePTFE graft. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Approximating the stress field within the unit cell of a fabric reinforced composite using replacement elements

    Science.gov (United States)

    Foye, R. L.

    1993-01-01

    This report concerns the prediction of the elastic moduli and the internal stresses within the unit cell of a fabric reinforced composite. In the proposed analysis no restrictions or assumptions are necessary concerning yarn or tow cross-sectional shapes or paths through the unit cell but the unit cell itself must be a right hexagonal parallelepiped. All the unit cell dimensions are assumed to be small with respect to the thickness of the composite structure that it models. The finite element analysis of a unit cell is usually complicated by the mesh generation problems and the non-standard, adjacent-cell boundary conditions. This analysis avoids these problems through the use of preprogrammed boundary conditions and replacement materials (or elements). With replacement elements it is not necessary to match all the constitutional material interfaces with finite element boundaries. Simple brick-shaped elements can be used to model the unit cell structure. The analysis predicts the elastic constants and the average stresses within each constituent material of each brick element. The application and results of this analysis are demonstrated through several example problems which include a number of composite microstructures.

  12. Fabrication of AO/LDH fluorescence composite and its detection of Hg2+in water.

    Science.gov (United States)

    Liu, Meng; Lv, Guocheng; Mei, Lefu; Wei, Yanke; Liu, Jieyuan; Li, Zhaohui; Liao, Libing

    2017-10-17

    Divalent mercury ion (Hg 2+ ) is one of the most common pollutants in water with high toxicity and significant bioaccumulation, for which sensitive and selective detection methods are highly necessary to carry out its detection and quantification. Fluorescence detection by organic dyes is a simple and rapid method in pollutant analyses and is limited because of quenching caused by aggregation dye molecules. Hydrotalcite (LDH) is one of the most excellent carrier materials. In this study, an organic dye acridine orange (AO) was successfully loaded on the LDH layers, which significantly inhibited fluorescence quenching of AO. The composite AO/LDH reaches the highest fluorescence intensity when the AO initial concentration is 5 mg/L. With its enhanced fluorescent property, the composite powder was fabricated to fluorescence test papers. The maximal fluorescence intensity was achieved with a pulp to AO/LDH ratio of 1:5 which can be used to detect Hg 2+ in water by naked eyes. Hg 2+ in aqueous solution can be detected by instruments in the range of 0.5 to 150 mM. The novelty of this study lies on both the development of a new type of mineral-dye composite material, as well as its practical applications for fast detection.

  13. Controlled fabrication and tunable photoluminescence properties of Mn2+ doped graphene–ZnO composite

    International Nuclear Information System (INIS)

    Luan, Xinglong; Zhang, Yihe; Tong, Wangshu; Shang, Jiwu; An, Qi; Huang, Hongwei

    2014-01-01

    Highlights: • Graphene–ZnO composites were synthesized by a mixed solvothermal method. • ZnO quantum dots are distributed uniformly on the graphene sheets. • A possible hypothesis is raised for the influence of graphene oxide on the nucleation of ZnO. • Mn 2+ doped graphene–ZnO composites were fabricated and the emission spectra can be tuned by doping. - Abstract: Graphene–ZnO composites (G–ZnO) with controlled morphology and photoluminescence property were synthesized by a mixed solvothermal method. Mixed solvent were composed by dimethyl sulfoxide and ethylene glycol. Fourier transform infrared spectroscopy, transmission electron microscopy and photoluminescence spectra were used to characterize G–ZnO. Graphene as a substrate can help the distribution and the dispersity of ZnO, and a possible model of the interaction between graphene oxide and ZnO particles is proposed. At the same time, graphene also reduce the size of ZnO particles to about 5 nm. Furthermore, Mn 2+ ions dopes G–ZnO successfully by the mixed solvothermal synthesis and the doping of Mn 2+ makes G–ZnO shift red from 465 nm to 548 nm and 554 nm in the emission spectrum. The changes of the emission spectrum by the adding of Mn 2+ make G–ZnO have tunable photoluminescence spectrum which is desirable for practical applications

  14. Fabrication and Dielectric Properties of AlN Filled Epoxy Nano-composites

    International Nuclear Information System (INIS)

    Gao Naiui; Yu Xin; Jin Haiyun; He Bo; Dong Pu; Gao Chao

    2011-01-01

    Epoxy resins were materials with excellent mechanical, electrical properties and good chemical stability. Thus, they had been used in various fields, especially in electrical and electronic application. However, because they were brittle material, the fields of application were limited. Adding nano-Aluminum Nitride (AlN) into Epoxy resins could improve the toughness of the composites, the thermal behaviors of composites could also be improved, but the influence on dielectric properties was not very clear. In this research, epoxy resin based composites were fabricated. The relationships between the dielectric properties and the nano-AlN particle content were investigated. The results showed that, both relative permittivity (ε r ) and dielectric loss tangent (tanδ) decreased to be less than that of monolithic epoxy when nano-AlN particle content was no more than certain amount, the DC volume resistivity (ρ v ) and low frequency resistivity decreased with increasing nano-AlN content (in certain range of content). AC breakdown strength (E B ) did not have an obvious tendency with nano-AlN content.

  15. Electronic Properties of Metallic Nanoclusters on Semiconductor Surfaces: Implications for Nanoelectronic Device Applications

    International Nuclear Information System (INIS)

    Lee, Takhee; Liu Jia; Chen, N.-P.; Andres, R.P.; Janes, D.B.; Reifenberger, R.

    2000-01-01

    We review current research on the electronic properties of nanoscale metallic islands and clusters deposited on semiconductor substrates. Reported results for a number of nanoscale metal-semiconductor systems are summarized in terms of their fabrication and characterization. In addition to the issues faced in large-area metal-semiconductor systems, nano-systems present unique challenges in both the realization of well-controlled interfaces at the nanoscale and the ability to adequately characterize their electrical properties. Imaging by scanning tunneling microscopy as well as electrical characterization by current-voltage spectroscopy enable the study of the electrical properties of nanoclusters/semiconductor systems at the nanoscale. As an example of the low-resistance interfaces that can be realized, low-resistance nanocontacts consisting of metal nanoclusters deposited on specially designed ohmic contact structures are described. To illustrate a possible path to employing metal/semiconductor nanostructures in nanoelectronic applications, we also describe the fabrication and performance of uniform 2-D arrays of such metallic clusters on semiconductor substrates. Using self-assembly techniques involving conjugated organic tether molecules, arrays of nanoclusters have been formed in both unpatterned and patterned regions on semiconductor surfaces. Imaging and electrical characterization via scanning tunneling microscopy/spectroscopy indicate that high quality local ordering has been achieved within the arrays and that the clusters are electronically coupled to the semiconductor substrate via the low-resistance metal/semiconductor interface

  16. Enzymatic hydrophobization of jute fabrics and its effect on the mechanical and interfacial properties of jute/PP composites

    Directory of Open Access Journals (Sweden)

    A. Dong

    2016-05-01

    Full Text Available In this work, a hydrophobic surface of lignocellulosic jute fabric was achieved via the laccase-mediated grafting of octadecylamine (OA on lignin moieties of jute aiming to improve the interfacial compatibility with the hydrophobic polypropylene (PP resins in the fiber-reinforced composites. Firstly, the surface and total elemental compositions of the modified jute fabrics were investigated by X-ray photoelectron spectroscopy (XPS and elemental analysis, respectively. The increases in the surface C/O ratio and total nitrogen content of jute fabrics after the laccase/OA treatment indicated that OA molecules were successfully grafted onto the jute surface mediated by laccase. The grafting percentage of OA on jute fabrics was 0.96%. The surface hydrophobicity of jute fabrics with static contact angle of 112.5°, advancing angle of 116.4° and receding angle of 42.7° supported the presence of nonpolar alkyl chains on the jute surface after the laccase-mediated OA-grafting. The tensile strength, tensile modulus as well as the elongation at break of the hydrophobized jute/PP composites were increased. The fracture surface of the composites became neat and the jute fibers on the section surface were surrounded by PP resins closely, which suggested better interfacial adhesion between the jute reinforcement and the PP resin.

  17. Highly selective GaN-nanowire/TiO2-nanocluster hybrid sensors for detection of benzene and related environment pollutants.

    Science.gov (United States)

    Aluri, Geetha S; Motayed, Abhishek; Davydov, Albert V; Oleshko, Vladimir P; Bertness, Kris A; Sanford, Norman A; Rao, Mulpuri V

    2011-07-22

    Nanowire-nanocluster hybrid chemical sensors were realized by functionalizing gallium nitride (GaN) nanowires (NWs) with titanium dioxide (TiO(2)) nanoclusters for selectively sensing benzene and other related aromatic compounds. Hybrid sensor devices were developed by fabricating two-terminal devices using individual GaN NWs followed by the deposition of TiO(2) nanoclusters using RF magnetron sputtering. The sensor fabrication process employed standard microfabrication techniques. X-ray diffraction and high-resolution analytical transmission electron microscopy using energy-dispersive x-ray and electron energy-loss spectroscopies confirmed the presence of the anatase phase in TiO(2) clusters after post-deposition anneal at 700 °C. A change of current was observed for these hybrid sensors when exposed to the vapors of aromatic compounds (benzene, toluene, ethylbenzene, xylene and chlorobenzene mixed with air) under UV excitation, while they had no response to non-aromatic organic compounds such as methanol, ethanol, isopropanol, chloroform, acetone and 1,3-hexadiene. The sensitivity range for the noted aromatic compounds except chlorobenzene were from 1% down to 50 parts per billion (ppb) at room temperature. By combining the enhanced catalytic properties of the TiO(2) nanoclusters with the sensitive transduction capability of the nanowires, an ultra-sensitive and selective chemical sensing architecture is demonstrated. We have proposed a mechanism that could qualitatively explain the observed sensing behavior.

  18. Progress in Imidazolium Ionic Liquids Assisted Fabrication of Carbon Nanotube and Graphene Polymer Composites

    Directory of Open Access Journals (Sweden)

    Xiaolin Xie

    2013-06-01

    Full Text Available Carbon nanotubes (CNTs and graphene sheets are the most promising fillers for polymer nanocomposites due to their superior mechanical, electrical, thermal optical and gas barrier properties, as well as high flame-retardant efficiency. The critical challenge, however, is how to uniformly disperse them into the polymer matrix to achieve a strong interface for good load transfer between the two. This problem is not new but more acute in CNTs and graphene, both because they are intrinsically insoluble and tend to aggregate into bundles and because their surfaces are atomically smooth. Over the past decade, imidazolium ionic liquids (Imi-ILs have played a multifunctional role (e.g., as solvents, dispersants, stabilizers, compatibilizers, modifiers and additives in the fabrication of polymer composites containing CNTs or graphene. In this review, we first summarize the liquid-phase exfoliation, stabilization, dispersion of CNTs and graphene in Imi-ILs, as well as the chemical and/or thermal reduction of graphene oxide to graphene with the aid of Imi-ILs. We then present a full survey of the literature on the Imi-ILs assisted fabrication of CNTs and graphene-based nanocomposites with a variety of polymers, including fluoropolymers, hydrocarbon polymers, polyacrylates, cellulose and polymeric ionic liquids. Finally, we give a future outlook in hopes of facilitating progress in this emerging area.

  19. Nanosized-Particle Dispersion-Strengthened Al Matrix Composites Fabricated by the Double Mechanical Alloying Process.

    Science.gov (United States)

    Kim, Chungseok

    2018-03-01

    The objective of this study was to fabricate an Al metal matrix composite strengthened by nanosized Al3Ti particles via double mechanical alloying process. Several Al-xTi alloys were fabricated, including Al-12%Ti, Al-15%Ti, and Al-12%Ti-1%Y2O3. The lattice parameter of as-milled state was calculated to be 4.0485 Å; after a milling time of 540 min, it was 4.0401 Å. This decrease was induced by Ti solutionizing into the Al matrix. The equivalent size of a coarse Al3Ti particle was 200-500 nm after the heat treatment; however, the particles were uniformly distributed and were refined through the MA2 process. The particle size of a Al3Ti phase was 30 nm or less, and the particles were uniformly distributed. These particles remained in a fine state in the matrix without growth and coarsening, even after the hot extrusion process. The microstructure of hot extruded alloys consisted of a uniform distribution of Al3Ti particles and other dispersoids in the Al matrix.

  20. A self-healing 3D woven fabric reinforced shape memory polymer composite for impact mitigation

    Science.gov (United States)

    Nji, Jones; Li, Guoqiang

    2010-03-01

    In this paper, a three-dimensional (3D) woven fabric reinforced shape memory polymer composite for impact mitigation was proposed, fabricated, programmed using a three-step strain-controlled thermomechanical cycle at a pre-strain level of 5% and machined to two groups of specimens (G1 and G2) with dimensions 152.4 mm × 101.6 mm × 12.7 mm. The specimens were impact tested, transversely, centrally and repeatedly with 32 and 42 J of energy. G1 specimens were healed after each impact until perforation occurred. G2 specimens were not healed after each impact and served as controls. At 32 J impact energy, G2 specimens were perforated at the 9th impact while G1 specimens lasted until the 15th impact; at 42 J impact energy, G2 specimens were perforated at the 5th impact while G1 specimens were perforated at the 7th impact. Visual inspection, C-scan, and scanning electron microscopy techniques were used to evaluate damage, failure modes, and healing efficiency.

  1. PCL/PLA Polymer Composite Filament Fabrication using Full Factorial Design (DOE) for Fused Deposition Modelling

    Science.gov (United States)

    Haq, R. H. A.; Khairilhijra, K. Rd.; Wahab, M. S.; Sa’ude, N.; Ibrahim, M.; Marwah, O. M. F.; Yusof, M. S.; Rahman, M. N. A.; Ariffin, A. M. T.; Hassan, M. F.; Yunos, M. Z.; Adzila, S.

    2017-10-01

    In this study, Polycaprolactone / Polylactice Acid (PCL/PLA) composite are used to fabricate filament wire with the specific diameter, which is in the range of 1.75 to 1.80 mm. Full factorial experimental design technique was used to study the main effects and the interaction effects between operational parameter which is (A) die temperature, (B) roller puller speed, (C) spindle speed and (D) inlet temperature. Besides that, there are two levels (-1 and +1) and the response are filament wire diameter. There are 16 numbers of runs and plus 8 centre points per blocks which makes the runs into 24 runs. From the experiment it shows that there are four factor that are significant effects on the filament wire diameter which is A, B, C and BC. The optimum parameter setting are also determined and there are 10 suggestions to achieve the target with different setting of parameter. The margin error for confirmation run is below than 15% when the parameter set at 6 Hz spindle speed, 4.99 rpm roller puller, 100.31 °C die temperature and 79.65 °C inlet temperature which can be noted that the confirmation run result is acceptable. The optimization parameter setting can use to continue in Fused Deposition Modelling (FDM). Filament wire from PCL/PLA are succesfully fabricated with acceptable diameter size and ready to be used for Fused Depotion Modelling process (FDM).

  2. RC beams shear-strengthened with fabric-reinforced-cementitious-matrix (FRCM) composite

    Science.gov (United States)

    Loreto, Giovanni; Babaeidarabad, Saman; Leardini, Lorenzo; Nanni, Antonio

    2015-12-01

    The interest in retrofit/rehabilitation of existing concrete structures has increased due to degradation and/or introduction of more stringent design requirements. Among the externally-bonded strengthening systems fiber-reinforced polymers is the most widely known technology. Despite its effectiveness as a material system, the presence of an organic binder has some drawbacks that could be addressed by using in its place a cementitious binder as in fabric-reinforced cementitious matrix (FRCM) systems. The purpose of this paper is to evaluate the behavior of reinforced concrete (RC) beams strengthened in shear with U-wraps made of FRCM. An extensive experimental program was undertaken in order to understand and characterize this composite when used as a strengthening system. The laboratory results demonstrate the technical viability of FRCM for shear strengthening of RC beams. Based on the experimental and analytical results, FRCM increases shear strength but not proportionally to the number of fabric plies installed. On the other hand, FRCM failure modes are related with a high consistency to the amount of external reinforcement applied. Design considerations based on the algorithms proposed by ACI guidelines are also provided.

  3. Mechanical properties of composites made of hybrid fabric impregnated with silica nanoparticles and epoxy resin

    Science.gov (United States)

    Kordani, N.; Alizadeh, M.; Lohrasby, F.; Khajavi, R.; Baharvandi, H. R.; Rezanejad, M.; Ahmadzadeh, M.

    2017-09-01

    In this study, the mechanical properties of composites will be examined which were made from Kenaf and hybrid fabric with a simple structure that was coated with epoxy resin and nano silica particles. This fabric cotton has a different situation in terms of yarn score and the type of fiber that is used in textiles. Nano silica particles of 200 nm, polyethylene glycol with 200 molecular weights and ethanol with mechanical weight molecular with ratio of 6:1 will be mixed. Suspension of 60% was chosen according to the silica particles. The D6264 standard test for concentrated force was carried out through the cone edge to determine the strength of each of the samples. Increasing of resistance against penetration in the Kenaf samples from the raw until impregnated with the shear thickening fluid is less than the hybrid samples. Slippage of the fibers with the change of round edge indenter to cone edge indenter has changed. Penetration by cone edge to the cloth is done with lower force and it shows the effect of slippage of fibers on the resistance of the penetration. Samples impregnated with the shear thickening fluid in comparison with epoxy resin have lower resistance. Slippage of natural fibers in comparison with synthetic fibers is lower and on the other hand the average of friction between fibers in the natural fibers is more than synthetic fibers.

  4. A self-healing 3D woven fabric reinforced shape memory polymer composite for impact mitigation

    International Nuclear Information System (INIS)

    Nji, Jones; Li, Guoqiang

    2010-01-01

    In this paper, a three-dimensional (3D) woven fabric reinforced shape memory polymer composite for impact mitigation was proposed, fabricated, programmed using a three-step strain-controlled thermomechanical cycle at a pre-strain level of 5% and machined to two groups of specimens (G1 and G2) with dimensions 152.4 mm × 101.6 mm × 12.7 mm. The specimens were impact tested, transversely, centrally and repeatedly with 32 and 42 J of energy. G1 specimens were healed after each impact until perforation occurred. G2 specimens were not healed after each impact and served as controls. At 32 J impact energy, G2 specimens were perforated at the 9th impact while G1 specimens lasted until the 15th impact; at 42 J impact energy, G2 specimens were perforated at the 5th impact while G1 specimens were perforated at the 7th impact. Visual inspection, C-scan, and scanning electron microscopy techniques were used to evaluate damage, failure modes, and healing efficiency

  5. Design and fabrication of microfluidic mixer from carbonyl iron–PDMS composite membrane

    KAUST Repository

    Li, Jiaxing

    2010-10-12

    This paper introduces a carbonyl iron-PDMS (CI-PDMS) composite magnetic elastomer in which carbonyl iron (CI) particles are uniformly distributed in a PDMS matrix. The CI particles and the PDMS were mixed at different weight ratios and tested to determine the influence of CI concentration. The magnetic and mechanical properties of the magnetic elastomers were characterized, respectively, by vibrating-sample magnetometer and by tensile testing using a mechanical analyzer. The elastomer was found to exhibit high magnetization and good mechanical flexibility. The morphology and deformation of the CI-PDMS membrane also were observed. A magnetically actuated microfluidic mixer (that is, a micromixer) integrated with CI-PDMS elastomer membranes was successfully designed and fabricated. The high efficiency and quality of the mixing makes possible the impressive potential applications of this unique CI-PDMS material in microfluidic systems. © Springer-Verlag 2010.

  6. Technique for fabricating individualized dentures with a gingiva-shade composite resin.

    Science.gov (United States)

    Park, Beom-Woo; Kim, Nam-Jin; Lee, Jonghyuk; Lee, Hae-Hyoung

    2016-05-01

    More natural dental esthetics have been sought by patients who wear conventional complete or partial dentures. Recently, gingiva-shade composite resins (GSCRs) have become available for replicating soft tissue for both fixed and removable prostheses. The technique presented is for fabricating individualized complete dentures. First the acrylic resin is mixed with a coloring agent and processed to modify the base shade of the denture. GSCRs are light polymerized onto a prepared space on the buccal surfaces of denture base to replicate the appearance of gingival tissues including blood vessels. The technique provides an outstanding natural, gingiva-like, appearance and allows complete dentures to harmonize with the individual patient's surrounding oral tissues. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  7. Damage development in woven fabric composites during tension-tension fatigue

    DEFF Research Database (Denmark)

    Hansen, U.

    1999-01-01

    of the operating fatigue damage mechanism(s). Fatigue leads to a degradation of material properties. Consequently, in connection with impact induced local stress raisers, fatigue produces continuously changing non-uniform stress fields because of stress redistribution effects. Other models addressing evolution......Impacted woven fabric composites were tested in tension-tension fatigue. In contrast to results from static testing, the effects of low energy impact damage in a fatigue environment were found to be the critical element leading to failure of the specimen. This difference emphasizes the need...... to identify and understand the fatigue damage mechanism. A relatively new non-destructive inspection technique using infrared thermography was found to be a very useful tool in detecting damage initiation and growth. Furthermore, this technique supplies valuable information to the characterization...

  8. Fabrication and electromagnetic performance of talc/NiTiO3 composite

    Science.gov (United States)

    Qin, Wen-Li; Xia, Tian; Ye, Ying; Zhang, Ping-Ping

    2018-02-01

    In this study, the electromagnetic (EM) performance of talc/NiTiO3 composite was evaluated. The morphology of talc displayed a lamella structure; there were many nanoparticles of NiTiO3 coated on the talc lamella. Thermal destruction occurred, which increased the surface area from 2.51 m2 g-1 to 79.09 m2 g-1 at the calcined stage at 650°C. The presence of NiTiO3 increased dielectric loss and magnetic loss of talc. The calculation of EM wave absorption of talc/NiTiO3 obtained a maximum reflection loss of -11.94 dB at the thickness of 6.85 mm; the optimum thickness for microwave absorption is 6.3-7.3 mm. This study revealed a new approach for fabricating an EM absorber and broadening applications of both talc and NiTiO3 in EM absorption.

  9. Fabrication of tungsten composite parts by direct HIP of powders in solid phase

    International Nuclear Information System (INIS)

    Mandet, F.; Palacio, M.; Boncoeur, M.

    1985-01-01

    Tungsten composites of the type W = 95%, Ni = 3.5% Fe = 1.5%, which are usually produced by cold isostatic pressing (CIP) followed by liquid phase natural sintering, are obtained here by direct hot isostatic pressing (HIP) of powders in solid phase. This method which is more reliable than the traditional process allows the production of large-sized parts while considerably reducing the required quantity of powder. The product fabrication by HIP is described as well as the results of the final material's character. Although the density of the product is similar to that of the commercial product, the mechanical properties in traction, and especially elongation, are weaker. Several hypotheses are suggested to explain this fall in ductility

  10. Damage Simulation in Non-Crimp Fabric Composite Plates Subjected to Impact Loads

    Science.gov (United States)

    Satyanarayana, Arunkumar; Bogert, Philip B.; Aitharaju, Venkat; Aashat, Satvir; Kia, Hamid

    2014-01-01

    Progressive failure analysis (PFA) of non-crimp fabric (NCF) composite laminates subjected to low velocity impact loads was performed using the COmplete STress Reduction (COSTR) damage model implemented through VUMAT and UMAT41 user subroutines in the frame works of the commercial finite element programs ABAQUS/Explicit and LS-DYNA, respectively. To validate the model, low velocity experiments were conducted and detailed correlations between the predictions and measurements for both intra-laminar and inter-laminar failures were made. The developed material and damage model predicts the peak impact load and duration very close with the experimental results. Also, the simulation results of delamination damage between the ply interfaces, in-plane matrix damages and fiber damages were all in good agreement with the measurements from the non-destructive evaluation data.

  11. Fluorescent DNA Stabilized Silver Nanoclusters as Biosensors

    Directory of Open Access Journals (Sweden)

    Alfonso Latorre

    2013-01-01

    Full Text Available DNA stabilized fluorescent silver nanoclusters are promising materials, of which fluorescent properties can be exploited to develop sensors. Particularly, the presence of a DNA strand in the structure has promoted the development of gene sensors where one part of the sensor is able to recognize the target gene sequence. Moreover, since oligonucleotides can be designed to have binding properties (aptamers a variety of sensors for proteins and cells have been developed using silver nanoclusters. In this review the applications of this material as sensors of different biomolecules are summarized.

  12. Efficient and clean synthesis of graphene supported platinum nanoclusters and its application in direct methanol fuel cell

    International Nuclear Information System (INIS)

    Ji Kai; Chang Gang; Oyama, Munetaka; Shang Xunzhong; Liu Xiong; He Yunbin

    2012-01-01

    Highlights: ► Pt nanoclusters/graphene (PtNCs/graphene) was synthesized within one-step process. ► Environment friendly ascorbic acid was chosen as the reductant. ► The synthesized PtNCs/graphene show superior electrocatalytic activity to methanol. ► PtNCs/graphene show superior electrocatalytic stability in methanol electrooxidation. - Abstract: The graphene supported platinum nanoclusters was synthesized by an efficient and clean method, in which graphene oxide and Pt ion precursor were reduced by ascorbic acid within one-step process. The obtained Pt nanoclusters attached graphene composite (PtNCs/graphene) was characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS), which can directly show that Pt nanoclusters successfully formed on graphene and well distributed on the edges and wrinkles of graphene sheets. The further electrochemical characterizations including cyclic voltammograms (CV), current–time methods indicated that PtNCs/graphene has significantly higher electrocatalytic activity and stability for methanol electrooxidation compared to the normal Vulcan XC-72 and graphite supported Pt nanoclusters, which will lead a further application as a new electrode material in direct methanol fuel cell (DMFC).

  13. Plasmon tsunamis on metallic nanoclusters.

    Science.gov (United States)

    Lucas, A A; Sunjic, M

    2012-03-14

    A model is constructed to describe inelastic scattering events accompanying electron capture by a highly charged ion flying by a metallic nanosphere. The electronic energy liberated by an electron leaving the Fermi level of the metal and dropping into a deep Rydberg state of the ion is used to increase the ion kinetic energy and, simultaneously, to excite multiple surface plasmons around the positively charged hole left behind on the metal sphere. This tsunami-like phenomenon manifests itself as periodic oscillations in the kinetic energy gain spectrum of the ion. The theory developed here extends our previous treatment (Lucas et al 2011 New J. Phys. 13 013034) of the Ar(q+)/C(60) charge exchange system. We provide an analysis of how the individual multipolar surface plasmons of the metallic sphere contribute to the formation of the oscillatory gain spectrum. Gain spectra showing characteristic, tsunami-like oscillations are simulated for Ar(15+) ions capturing one electron in distant collisions with Al and Na nanoclusters.

  14. Disposal Options of Bamboo Fabric-Reinforced Poly(Lactic Acid Composites for Sustainable Packaging: Biodegradability and Recyclability

    Directory of Open Access Journals (Sweden)

    M.R. Nurul Fazita

    2015-08-01

    Full Text Available The present study was conducted to determine the recyclability and biodegradability of bamboo fabric-reinforced poly(lactic acid (BF-PLA composites for sustainable packaging. BF-PLA composite was recycled through the granulation, extrusion, pelletization and injection processes. Subsequently, mechanical properties (tensile, flexural and impact strength, thermal stability and the morphological appearance of recycled BF-PLA composites were determined and compared to BF-PLA composite (initial materials and virgin PLA. It was observed that the BF-PLA composites had the adequate mechanical rigidity and thermal stability to be recycled and reused. Moreover, the biodegradability of BF-PLA composite was evaluated in controlled and real composting conditions, and the rate of biodegradability of BF-PLA composites was compared to the virgin PLA. Morphological and thermal characteristics of the biodegradable BF-PLA and virgin PLA were obtained by using environment scanning electron microscopy (ESEM and differential scanning calorimetry (DSC, respectively. The first order decay rate was found to be 0.0278 and 0.0151 day−1 in a controlled composting condition and 0.0008 and 0.0009 day−1 in real composting conditions for virgin PLA and BF-PLA composite, respectively. Results indicate that the reinforcement of bamboo fabric in PLA matrix minimizes the degradation rate of BF-PLA composite. Thus, BF-PLA composite has the potential to be used in product packaging for providing sustainable packaging.

  15. Fabrication of High Thermal Conductivity NARloy-Z-Diamond Composite Combustion Chamber Liner for Advanced Rocket Engines

    Science.gov (United States)

    Bhat, Biliyar N.; Greene, Sandra E.; Singh, Jogender

    2016-01-01

    This paper describes the process development for fabricating a high thermal conductivity NARloy-Z-Diamond composite (NARloy-Z-D) combustion chamber liner for application in advanced rocket engines. The fabrication process is challenging and this paper presents some details of these challenges and approaches used to address them. Prior research conducted at NASA-MSFC and Penn State had shown that NARloy-Z-40%D composite material has significantly higher thermal conductivity than the state of the art NARloy-Z alloy. Furthermore, NARloy-Z-40 %D is much lighter than NARloy-Z. These attributes help to improve the performance of the advanced rocket engines. Increased thermal conductivity will directly translate into increased turbopump power, increased chamber pressure for improved thrust and specific impulse. Early work on NARloy-Z-D composites used the Field Assisted Sintering Technology (FAST, Ref. 1, 2) for fabricating discs. NARloy-Z-D composites containing 10, 20 and 40vol% of high thermal conductivity diamond powder were investigated. Thermal conductivity (TC) data. TC increased with increasing diamond content and showed 50% improvement over pure copper at 40vol% diamond. This composition was selected for fabricating the combustion chamber liner using the FAST technique.

  16. Matrix Sputtering Method: A Novel Physical Approach for Photoluminescent Noble Metal Nanoclusters.

    Science.gov (United States)

    Ishida, Yohei; Corpuz, Ryan D; Yonezawa, Tetsu

    2017-12-19

    Noble metal nanoclusters are believed to be the transition between single metal atoms, which show distinct optical properties, and metal nanoparticles, which show characteristic plasmon absorbance. The interesting properties of these materials emerge when the particle size is well below 2 nm, such as photoluminescence, which has potential application particularly in biomedical fields. These photoluminescent ultrasmall nanoclusters are typically produced by chemical reduction, which limits their practical application because of the inherent toxicity of the reagents used in this method. Thus, alternative strategies are sought, particularly in terms of physical approaches, which are known as "greener alternatives," to produce high-purity materials at high yields. Thus, a new approach using the sputtering technique was developed. This method was initially used to produce thin films using solid substrates; now it can be applied even with liquid substrates such as ionic liquids or polyethylene glycol as long as these liquids have a low vapor pressure. This revolutionary development has opened up new areas of research, particularly for the synthesis of colloidal nanoparticles with dimensions below 10 nm. We are among the first to apply the sputtering technique to the physical synthesis of photoluminescent noble metal nanoclusters. Although typical sputtering systems have relied on the effect of surface composition and viscosity of the liquid matrix on controlling particle diameters, which only resulted in diameters ca. 3-10 nm, that were all plasmonic, our new approach introduced thiol molecules as stabilizers inspired from chemical methods. In the chemical syntheses of metal nanoparticles, controlling the concentration ratio between metal ions and stabilizing reagents is a possible means of systematic size control. However, it was not clear whether this would be applicable in a sputtering system. Our latest results showed that we were able to generically produce a

  17. Effect of fabrication processes on mechanical properties of glass fiber reinforced polymer composites for 49 meter (160 foot recreational yachts

    Directory of Open Access Journals (Sweden)

    Dave (Dae-Wook Kim

    2010-03-01

    Full Text Available Polymer composite materials offer high strength and stiffness to weight ratio, corrosion resistance, and total life cost reductions that appeal to the marine industry. The advantages of composite construction have led to their incorporation in U.S. yacht hull structures over 46 meters (150 feet in length. In order to construct even larger hull structures, higher quality composites with lower cost production techniques need to be developed. In this study, the effect of composite hull fabrication processes on mechanical properties of glass fiber reinforced plastic (GFRP composites is presented. Fabrication techniques investigated during this study are hand lay-up (HL, vacuum infusion (VI, and hybrid (HL + VI processes. Mechanical property testing includes: tensile, compressive, and ignition loss sample analysis. Results demonstrate that the vacuum pressure implemented during composite fabrication has an effect on mechanical properties. The VI processed GFRP yields improved mechanical properties in tension/compression strengths and tensile modulus. The hybrid GFRP composites, however, failed in a sequential manor, due to dissimilar failure modes in the HL and VI processed sides. Fractography analysis was conducted to validate the mechanical property testing results.

  18. Fabrication, Microstructure, and Mechanical Property of NiAl-based Composite with Microlaminated Architecture by Roll Bonding and Annealing Treatment

    Science.gov (United States)

    Fan, Guohua; Wang, Qingwei; Geng, Lin; Zhang, Jie; Hu, Weiping; Du, Yan

    2016-03-01

    Microlaminated TiB2-NiAl composite sheets consisting of alternating TiB2-rich and monolithic NiAl layers have been successfully fabricated by roll bonding and reaction annealing of Ni sheets and TiB2/Al composite sheets. Solid-liquid reaction mechanisms including diffusion reaction and precipitation were determined in the initial multi-laminated Ni-(TiB2/Al) sheets at 1473 K (1200 °C). After fabrication, the microlaminated composite sheets have a strong texture with parallel to normal direction formed by phase transformation inheritance from initial rolling texture of Ni sheets via diffusion reaction. Both the tensile strength and elongation of the microlaminated TiB2-NiAl composite sheets were significantly improved when tested at the temperatures above BDTT, which could be attributed to the unique laminated structure, bimodal grain size distribution in NiAl matrix, and enhanced interface bonding between both layers.

  19. Green Route Fabrication of Graphene Oxide Reinforced Polymer Composites with Enhanced Mechanical Properties

    International Nuclear Information System (INIS)

    Mahendran, R.; Sridharan, D.; Santhakumar, K.; Gnanasekaran, G.

    2016-01-01

    A facile and “Green” route has been applied to fabricate graphene oxide (GO) reinforced polymer composites utilizing “deionized water” as solvent. The GO was reinforced into water soluble poly(vinyl alcohol) (PVA) and poly-2-acrylamido-2-methyl-1-propanesulfonic acid (PAMPS) matrix by ultrasonication followed by mechanical stirring. The incorporation and dispersion of the GO in the polymer matrix were analyzed by XRD, FE-SEM, AFM, FT-IR, and TGA. Further, the FE-SEM and AFM images revealed that the surface roughness and agglomeration of the GO in the polymer matrix increased by increasing its concentration. Ionic exchange capacity, proton conductivity, and tensile texture results showed that the reinforcement of GO in the polymer matrix enhances the physicochemical properties of the host polymer. These PVA/PAMPS/GO nano composites showed improved mechanical stability compared to the pristine polymer, because of strong interfacial interactions within the components and homogeneous dispersion of the GO sheets in the PVA/PAMPS matrix.

  20. Design, fabrication, and testing of a SMA hybrid composite jet engine chevron

    Science.gov (United States)

    Turner, Travis L.; Cabell, Randolph H.; Cano, Roberto J.; Fleming, Gary A.

    2006-01-01

    Control of jet noise continues to be an important research topic. Exhaust nozzle chevrons have been shown to reduce jet noise, but parametric effects are not well understood. Additionally, thrust loss due to chevrons at cruise suggests significant benefit from deployable chevrons. The focus of this study is development of an active chevron concept for the primary purpose of parametric studies for jet noise reduction in the laboratory and technology development to leverage for full scale systems. The active chevron concept employed in this work consists of a laminated composite structure with embedded shape memory alloy (SMA) actuators, termed a SMA hybrid composite (SMAHC). The actuators are embedded on one side of the middle surface such that thermal excitation generates a moment and deflects the structure. A brief description of the chevron design is given followed by details of the fabrication approach. Results from bench top tests are presented and correlated with numerical predictions from a model for such structures that was recently implemented in MSC.Nastran and ABAQUS. Excellent performance and agreement with predictions is demonstrated. Results from tests in a representative flow environment are also presented. Excellent performance is again achieved for both open- and closed-loop tests, the latter demonstrating control to a specified immersion into the flow. The actuation authority and immersion performance is shown to be relatively insensitive to nozzle pressure ratio (NPR). Very repeatable immersion control with modest power requirements is demonstrated.

  1. ESTIMATION OF THE DYNAMIC PROPERTIES OF EPOXY GLASS FABRIC COMPOSITES WITH NATURAL RUBBER PARTICLE INCLUSIONS

    Directory of Open Access Journals (Sweden)

    H. Ravi Sankar

    2013-06-01

    Full Text Available Conventional materials are being replaced in the field of engineering by composite materials, due to their tailorable properties and high specific properties. These materials are extensively used in structural applications. Damping is one of the important properties of the materials used in structures, and needs to be enhanced in order to reduce structural vibrations. In the present work, the improvement of the material damping of glass fabric epoxy composites with particle rubber inclusions is studied. The effect of particle size on the damping and stiffness parameters at different frequencies and temperatures is studied experimentally. Considerable enhancement in damping without significant reduction in stiffness is observed at lower particle sizes. The damping property in both bending and shear modes is more with 0.254 mm rubber particle inclusions among the selected sizes. A lower reduction in stiffness is observed with the inclusion of lower particle sizes (0.254 mm and 0.09 mm when compared with higher particle sizes. An ANN-based prediction model is developed to predict these properties for a given frequency/temperature and particle size. The predicted values are very close to the experimental values with an maximum error of 5%.

  2. Fabrication of epoxy composites with large-pore sized mesoporous silica and investigation of their thermal expansion.

    Science.gov (United States)

    Suzuki, Norihiro; Kiba, Shosuke; Yamauchi, Yusuke

    2012-02-01

    We fabricate epoxy composites with low thermal expansion by using mesoporous silica particles with a large pore diameter (around 10 nm) as inorganic fillers. From a simple calculation, almost all the mesopores are estimated to be completely filled with the epoxy polymer. The coefficient of linear thermal expansion (CTE) values of the obtained epoxy composites proportionally decrease with the increase of the mesoporous silica content.

  3. A fabrication method of unique Nafion® shapes by painting for ionic polymer-metal composites

    Science.gov (United States)

    Trabia, Sarah; Hwang, Taeseon; Kim, Kwang J.

    2016-08-01

    Ionic polymer-metal composites (IPMC) are useful actuators because of their ability to be fabricated in different shapes and move in various ways. However, producing unique or intricate shapes can be difficult based upon the current fabrication techniques. Presented here is a fabrication method of producing the Nafion® membrane or thin film through a painting method. Using an airbrush, a Nafion water dispersion is sprayed onto an acrylonitrile butadiene styrene surface with a stencil of the desired shape. To verify that this method of fabrication produces a Nafion membrane similar to that which is commercially available, a sample that was made using the painting method and Nafion 117 purchased from DuPont™ were tested for various characteristics and compared. The results show promising similarities. The painted Nafion sample was chemically plated with platinum and compared with a traditional IPMC for its displacement and blocking force capabilities. The painted IPMC sample showed comparable results.

  4. The suitability of XRF analysis for compositional classification of archaeological ceramic fabric: A comparison with a previous NAA study

    Energy Technology Data Exchange (ETDEWEB)

    Padilla, R. [Centro de Aplicaciones Tecnologicas y Desarrollo Nuclear (CEADEN), Laboratorio de Analisis Quimico, Calle 30 no. 502, Playa, Ciudad Habana (Cuba)]. E-mail: roman.padilla@infomed.sld.cu; Espen, P. van [University of Antwerp (Belgium); Torres, P.P. Godo [Centro de Antropologia, Havana (Cuba)

    2006-02-03

    The main drawbacks of EDXRF techniques, restricting its more frequent use for the specific purpose of compositional analysis of archaeological ceramic fabric, have been the insufficient sensitivity to determine some important elements (like Cr, REE, among others), a somewhat worse precision and the inability to perform standard-less quantitative procedures in the absence of suitable certified reference materials (CRM) for ceramic fabric. This paper presents the advantages of combining two energy dispersive X-ray fluorescence methods for fast and non-destructive analysis of ceramic fabric with increased sensitivity. Selective polarized excitation using secondary targets (EDPXRF) and radioisotope excitation (R-XRF) using a {sup 241}Am source. The analytical performance of the methods was evaluated by analyzing several CRM of sediment type, and the fitness for the purpose of compositional classification was compared with that obtained by using Instrumental Neutron Activation Analysis in a previous study of Cuban aborigine pottery.

  5. Facile fabrication of TiO2-graphene composite with enhanced photovoltaic and photocatalytic properties by electrospinning.

    Science.gov (United States)

    Zhu, Peining; Peining, Zhu; Nair, A Sreekumaran; Shengjie, Peng; Shengyuan, Yang; Ramakrishna, Seeram

    2012-02-01

    We report the fabrication of one-dimensional TiO(2)-graphene nanocomposite by a facile and one-step method of electrospinning. The unique nanostructured composite showed a significant enhancement in the photovoltaic and photocatalytic properties in comparison to TiO(2) as demonstrated in dye-sensitized solar cells and photodegradation of methyl orange.

  6. Property improvement of stainless-steel-base surface composites fabricated by high-energy electron-beam irradiation

    Science.gov (United States)

    Shin, Keesam; Lee, Sunghak

    2003-12-01

    This is a study on the fabrication of surface composites of SiC, TiC particulates, and AISI 304 substrate by high voltage electron beam irradiation. Using CaF2 powders as flux, two kinds of surface composites were fabricated for a comparative analysis of the microstructural modification and mechanical properties. Through the employed process, the powders and substrate surface were melted and surface composite layers were successfully formed in both cases. In the specimen fabricated with SiC powders, a volume fraction of Cr23C6 particles (-22 vol.%) were homogeneously distributed along solidification cell boundaries. The large amount of Cr23C6 particles in combination with solid solution hardening of Si in the matrix resulted in the improved hardness and wear resistance of the surface composite layer, that are 2 to 3 times those of the substrate. In the specimen fabricated with SiC and Ti+SiC powders, TiC and Cr23C6 particles were precipitated without precipitation of SiC.

  7. 3d Finite Element Modelling of Non-Crimp Fabric Based Fibre Composite Based on X-Ray Ct Data

    DEFF Research Database (Denmark)

    Jespersen, Kristine Munk; Asp, Leif; Mikkelsen, Lars Pilgaard

    2017-01-01

    initiation and progression in the material. In the current study, the real bundle structure inside a non-crimp fabric based fibre composite is extracted from 3D X-ray CT images and imported into ABAQUS for numerical modelling.The local stress concentrations when loaded in tension caused by the fibre bundle...

  8. Peptide-stabilized, fluorescent silver nanoclusters

    DEFF Research Database (Denmark)

    Gregersen, Simon; Vosch, Tom André Jos; Jensen, Knud Jørgen

    2016-01-01

    Few-atom silver nanoclusters (AgNCs) can exhibit strong fluorescence; however, they require ligands to prevent aggregation into larger nanoparticles. Fluorescent AgNCs in biopolymer scaffolds have so far mainly been synthesized in solution, and peptides have only found limited use compared to DNA...

  9. The fcc structure isomerization in gold nanoclusters.

    Science.gov (United States)

    Zhuang, Shengli; Liao, Lingwen; Li, Man-Bo; Yao, Chuanhao; Zhao, Yan; Dong, Hongwei; Li, Jin; Deng, Haiteng; Li, Lingling; Wu, Zhikun

    2017-10-12

    Structural isomerization is an important concept in organic chemistry and it is recently found to be applicable to thiolated gold nanoparticles. However, to the best of our knowledge, the isomerization with the kernel structure of the cluster changed while maintaining fcc packing was not previously found. Here, we report such a structural isomerization by synthesizing a novel gold nanocluster and solving its atomic structure. The as-obtained novel gold nanocluster Au 52 (PET) 32 (PET = phenylethanethiolate) has completely the same Au/S molar ratio as a well-known gold nanocluster Au 52 (TBBT) 32 (TBBT = 4-tert-butyl-benzenethiolate) but an essentially different fcc structure. As a result of fcc structure isomerization, Au 52 (PET) 32 has remarkably different UV/vis/NIR absorption from Au 52 (TBBT) 32 . Another interesting finding in this work is that the kernel of Au 52 (PET) 32 has high-indexed (311)-like facets, which is not previously reported in the structures of gold nanoclusters to the best of our knowledge.

  10. The design and fabrication of highly piezoelectric polymeric composites and their use in responsive devices

    Science.gov (United States)

    Baur, Cary Allen

    In this work, novel approaches to the design of highly piezoelectric and flexible polymer composites were explored. Diverging from past work focused on the addition of piezoelectric particles into polymer matrices, this research explores the ability to increase the piezoelectric performance of a host polymer through the incorporation of charge via polarizable, organic particles. The ability to insert charge into polymers, known as electrets, is well documented but widely considered impractical because of the low lifetime and temperature resistance of the inserted charge. Through the addition of particles that are polarizable, charge can be inserted into a system in a stable manner that results in highly charged materials with long lifetimes. Here, carbon structures, such as Buckminsterfullerenes (C60) and single-walled nanotubes (SWNTs), were composited into poly(vinylidene difluoride) at very low loading levels (0.05-0.25 wt%), resulting in the ability to insert stable charge into the system. We show that these highly charged systems can result in a doubling of the piezoelectric response of the host polymer when optimized. The low amount of nanoparticle filler required to improve these materials allows for the advantageous properties of the polymer matrix such as flexibility and compliance to be preserved, enabling highly piezoelectric and flexible system. This dissertation outlines research efforts towards the design and fabrication of 1) polymer composites with high piezoelectric response, 2) piezoelectric composites with increased operating temperatures, 3) motion control devices that incorporate piezoelectric materials and shape memory polymers, and 4) artificial muscles with piezoelectric polymers. The piezoelectric polymer composites developed in this work have potential to be utilized as highly efficient, flexible energy harvesters that can be used to capture ambient energy from environmental vibrations and motion from the human body. As actuators, these

  11. Electrolytic deposition of PZT on carbon fibers for fabricating multifunctional composites

    International Nuclear Information System (INIS)

    Lin, Y; Shaffer, J W; Sodano, H A

    2010-01-01

    Piezoelectric fiber composites (PFCs) have been developed in order to overcome the fragile nature of monolithic piezoelectric materials by embedding piezoceramic inclusions into a polymer matrix. The flexible nature of the polymer matrix protects the piezoelectric fiber from damage or fracture under mechanical loading and allows the composites to be easily conformed to curved surfaces for use in many applications. Although PFCs have many useful properties, they still suffer from several drawbacks, namely the required separate electrodes make it impossible to embed the composites into the host structure, and the relatively low tensile modulus of the piezoelectric inclusion means that it contributes little to structural properties. To resolve the inadequacies of current PFCs, a novel active structural fiber (ASF) was developed that can be embedded into a composite structure to perform sensing and actuation, and provide load bearing functionality. The concept and feasibility of this ASF has been validated by coating a silicon carbide (SiC) fiber with a barium titanate (BaTiO 3 ) shell using electrophoresis deposition techniques. However, lead based ceramics react with SiC fiber during high temperature sintering and thus the use of these highly coupled piezoceramics requires alternative deposition approaches. This paper will introduce a new ASF fabricated by coating a single carbon fiber with a concentric PZT (PbZr 0.52 Ti 0.48 O 3 ) shell using electrolytic deposition (ELD). ELD quickly and uniformly coats the fiber and, since the PZT precursor has a low crystallization temperature, the carbon fiber is not exposed to high sintering temperatures which typically degrade the in-plane material properties of the fiber and composite. Carbon fiber has been widely used in industry and studied in academia due to its excellent mechanical properties, while PZT has been extensively used for sensing or actuation because of its high piezoelectric coupling. Crystal structures of the

  12. Fabrication and application of flexible graphene silk composite film electrodes decorated with spiky Pt nanospheres

    Science.gov (United States)

    Liang, Bo; Fang, Lu; Hu, Yichuan; Yang, Guang; Zhu, Qin; Ye, Xuesong

    2014-03-01

    A free-standing graphene silk composite (G/S) film was fabricated via vacuum filtration of a mixed suspension of graphene oxide and silk fibres, followed by chemical reduction. Spiky structured Pt nanospheres were grown on the film substrate by cyclic voltammetry electrodeposition. The electrical and mechanical performance of a single graphene coated silk fibre was investigated. The conductivity of a single graphene coated silk fibre is 57.9 S m-1. During 1000 bending measurements, the conductivity was stable and showed negligible variation. The G/S film has a sheet resistivity of 90 Ω □-1 with a porous and hierarchical structure. The spiky Pt nanosphere decorated G/S film was directly used as a H2O2 electrode with a sensitivity of 0.56 mA mM-1 cm-2, a linear range of 0-2.5 mM and an ultralow detection limit of 0.2 μM (S/N = 3). A glucose biosensor electrode was further fabricated by enzyme immobilization. The results show a sensitivity of 150.8 μA mM-1 cm-2 and a low detection limit of 1 μM (S/N = 3) for glucose detection. The strategy of coating graphene sheets on a silk fibre surface provides a new approach for developing electrically conductive biomaterials, tissue engineering scaffolds, bendable electrodes, and wearable biomedical devices.A free-standing graphene silk composite (G/S) film was fabricated via vacuum filtration of a mixed suspension of graphene oxide and silk fibres, followed by chemical reduction. Spiky structured Pt nanospheres were grown on the film substrate by cyclic voltammetry electrodeposition. The electrical and mechanical performance of a single graphene coated silk fibre was investigated. The conductivity of a single graphene coated silk fibre is 57.9 S m-1. During 1000 bending measurements, the conductivity was stable and showed negligible variation. The G/S film has a sheet resistivity of 90 Ω □-1 with a porous and hierarchical structure. The spiky Pt nanosphere decorated G/S film was directly used as a H2O2 electrode with a

  13. The effects of composition and sintering temperature on the silica foam fabricated by slurry method

    Energy Technology Data Exchange (ETDEWEB)

    Baharom, Syazwani, E-mail: hd140001@siswa.uthm.edu.my; Ahmad, Sufizar, E-mail: sufizar@uthm.edu.my; Taib, Hariati, E-mail: hariati@uthm.edu.my; Muda, Rizamarhaiza, E-mail: hd130013@siswa.uthm.edu.my [Department of Material and Design Engineering, Faculty of Mechanical and Manufacturing Engineering, Universiti Tun Hussein Onn Malaysia (UTHM), 86400 Parit Raja, Batu Pahat, Johor (Malaysia)

    2016-07-19

    Reticulated ceramic or open pore ceramic foam is a well-known material which exhibits extremely high porosities, with a significant degree of interconnectivity that makes them desirable in a wide range of applications. There were broad types of ceramic foam fabrication method such as polymeric sponge method, direct foaming, and starch consolidation. In this study, the slurry method has been chosen to fabricate Silica (SiO{sub 2}) foam. In this process, Polyurethane (PU) foam template was dipped into ceramic slurry and followed by drying and sintering to obtain foam which contains porosity in the range of 50% to 70%. The compositions of SiO{sub 2} were varied starting from 55 wt.%, 60 wt.%, 65 wt.% and 70 wt.%. The samples of SiO{sub 2} that have been dipped and dried were sintered at 900°C, 1000°C, 1100°C, and 1250°C. The sintered SiO{sub 2} ceramic foam samples were characterized to observe their morphology, and physical properties. Thus, the microstructure of the SiO{sub 2} ceramic foams samples was examined by Scanning Electron Microscopy (SEM), and Electron Dispersive Spectroscopy (EDS). Meanwhile, the physical properties of the SiO{sub 2} ceramic foam samples such as the total porosity (%) and bulk density were determined using Archimedes method. It was found that the density of ceramic foam produced was in the range of 0.25 g/cm{sup 3} up to 0.75 g/cm{sup 3}, whereas the level of porosity percentage was in the range of 61.81% to 82.18% with the size of open pore or window cells were in between 141 µm up to 626 µm.

  14. Mechanical properties of banana/kenaf fiber-reinforced hybrid polyester composites: Effect of woven fabric and random orientation

    International Nuclear Information System (INIS)

    Alavudeen, A.; Rajini, N.; Karthikeyan, S.; Thiruchitrambalam, M.; Venkateshwaren, N.

    2015-01-01

    Highlights: • This paper is presents the fabrications of kenaf/banana fiber hybrid composites. • Effect of weaving pattern and random orientation on mechanical properties was studied. • Role of interfacial adhesion due to chemical modifications were analyzed with the aid of SEM. • Hybridization of kenaf and banana fibers in plain woven composites exhibits maximum mechanical strength. - Abstract: The present work deals with the effect of weaving patterns and random orientatation on the mechanical properties of banana, kenaf and banana/kenaf fiber-reinforced hybrid polyester composites. Composites were prepared using the hand lay-up method with two different weaving patterns, namely, plain and twill type. Of the two weaving patterns, the plain type showed improved tensile properties compared to the twill type in all the fabricated composites. Furthermore, the maximum increase in mechanical strength was observed in the plain woven hybrid composites rather than in randomly oriented composites. This indicates minimum stress development at the interface of composites due to the distribution of load transfer along the fiber direction. Moreover, alkali (NaOH) and sodium lauryl sulfate (SLS) treatments appear to provide an additional improvement in mechanical strength through enhanced interfacial bonding. Morphological studies of fractured mechanical testing samples were performed by scanning electron microscopy (SEM) to understand the de-bonding of fiber/matrix adhesion

  15. Multi scale analysis by acoustic emission of damage mechanisms in natural fibre woven fabrics/epoxy composites.

    Directory of Open Access Journals (Sweden)

    Touchard F.

    2010-06-01

    Full Text Available This paper proposes to develop an experimental program to characterize the type and the development of damage in composite with complex microstructure. A multi-scale analysis by acoustic emission has been developed and applied to hemp fibre woven fabrics/epoxy composite. The experimental program consists of tensile tests performed on single yarn, neat epoxy resin and composite materials to identify their AE amplitude signatures. A statistical analysis of AE amplitude signals has been realised and correlated with microscopic observations. Results have enabled to identify three types of damage in composites and their associated AE amplitudes: matrix cracking, interfacial debonding and reinforcement damage and fracture. Tracking of these damage mechanisms in hemp/epoxy composites has been performed to show the process of damage development in natural fibre reinforced composites.

  16. Characterizations of Polystyrene-Based Hybrid Particles Containing Hydrophobic Mg(OH2 Powder and Composites Fabricated by Employing Resultant Hybrid Particles

    Directory of Open Access Journals (Sweden)

    Shuichi Kimura

    2007-01-01

    unchanged, even when the ST-1 powder content increased from 10 to 50 phr. Furthermore, a composite fabricated by employing the hybrid particles achieved homogenous distribution of ST-1 powder and showed a higher oxygen index than that of a composite fabricated by directly mixing of PS pellets and ST-1 powder.

  17. Experimental and Theoretical Investigations of the Impact Localization of a Passive Smart Composite Plate Fabricated Using Piezoelectric Materials

    Directory of Open Access Journals (Sweden)

    M. M. S. Dezfouli

    2013-01-01

    Full Text Available Two passive smart composite plates are fabricated using one and two PZT patches that are cheaper than the PZT wafer. The composite plate is fabricated in low temperature through the hand lay-up method to avoid PZT patch decoupling and wire spoiling. The locus of the impact point is identified using the output voltage to identify the impact location using one sensor. The output voltages of the sensors are analyzed to identify the impact location using two sensors. The locations of the impacts are determined based on the crossing points of two circles and the origin of an intended Cartesian coordinate system that is concentric with one of the sensors. This study proposes the impact location identification of the passive smart composite using the low-cost PZT patch PIC155 instead of common embedded materials (wafer and element piezoelectric.

  18. Fabrication, characterization and biomedical application of two-nozzle electrospun polycaprolactone/zein-calcium lactate composite nonwoven mat.

    Science.gov (United States)

    Liao, Nina; Joshi, Mahesh Kumar; Tiwari, Arjun Prasad; Park, Chan-Hee; Kim, Cheol Sang

    2016-07-01

    The objective of the current work is to incorporate calcium lactate (CL) into polycaprolactone (PCL)/zein composite micro/nanofibrous scaffolds via electrospinning to engineer bone tissue. In this study, a composite micro/nano fibrous scaffold was fabricated using a single two-nozzle electrospinning system to combine indicative nanofibers from a blended solution of zein-CL and micro-sized fibers from a PCL solution. Incorporation of the CL into the PCL/zein fibers were shown to improve the wettability, tensile strength and biological activity of the composite mats. Moreover, the composite mats have a high efficiency to nucleate calcium phosphate from simulated body fluid (SBF) solution. An in vitro cell culture with osteoblast cells demonstrated that the electrospun composite mats possessed improved biological properties, including a better cell adhesion, spread and proliferation. This study has demonstrated that the PCL/zein-CL composite provides a simple platform to fabricate a new biomimetic scaffold for bone tissue engineering, which can recapitulate both the morphology of extracellular matrix and composition of the bone. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Design, fabrication, and properties of 2-2 connectivity cement/polymer based piezoelectric composites with varied piezoelectric phase distribution

    International Nuclear Information System (INIS)

    Dongyu, Xu; Xin, Cheng; Shifeng, Huang; Banerjee, Sourav

    2014-01-01

    The laminated 2-2 connectivity cement/polymer based piezoelectric composites with varied piezoelectric phase distribution were fabricated by employing Lead Zirconium Titanate ceramic as active phase, and mixture of cement powder, epoxy resin, and hardener as matrix phase with a mass proportion of 4:4:1. The dielectric, piezoelectric, and electromechanical coupling properties of the composites were studied. The composites with large total volume fraction of piezoelectric phase have large piezoelectric strain constant and relative permittivity, and the piezoelectric and dielectric properties of the composites are independent of the dimensional variations of the piezoelectric ceramic layer. The composites with small total volume fraction of piezoelectric phase have large piezoelectric voltage constant, but also large dielectric loss. The composite with gradually increased dimension of piezoelectric ceramic layer has the smallest dielectric loss, and that with the gradually increased dimension of matrix layer has the largest piezoelectric voltage constant. The novel piezoelectric composites show potential applications in fabricating ultrasonic transducers with varied surface vibration amplitude of the transducer

  20. Design, Fabrication, and Testing of a Composite Rack Prototype in Support of the Deep Space Habitat Program

    Science.gov (United States)

    Smith, Russ; Hagen, Richard

    2015-01-01

    In support of the Deep Space Habitat project a number of composite rack prototypes were developed, designed, fabricated and tested to various extents ( with the International Standard Payload Rack configuration, or crew quarters, as a baseline). This paper focuses specifically on a composite rack prototype with a direct tie in to Space Station hardware. The outlined prototype is an all composite construction, excluding metallic fasteners, washers, and their associated inserts. The rack utilizes braided carbon composite tubing for the frame with the sidewalls, backwall and flooring sections utilizing aircraft grade composite honeycomb sandwich panels. Novel additively manufactured thermoplastic joints and tube inserts were also developed in support of this effort. Joint and tube insert screening tests were conducted at a preliminary level. The screening tests allowed for modification, and enhancement, of the fabrication and design approaches, which will be outlined. The initial joint tests did not include mechanical fasteners. Adhesives were utilized at the joint to composite tube interfaces, along with mechanical fasteners during final fabrication (thus creating a stronger joint than the adhesive only variant). In general the prototype was focused on a potential in-space assembly approach, or kit-of-parts construction concept, which would not necessarily require the inclusion of an adhesive in the joint regions. However, given the tie in to legacy Station hardware (and potential flight loads with imbedded hardware mass loadings), the rack was built as stiff and strong as possible. Preliminary torque down tests were also conducted to determine the feasibility of mounting the composite honeycomb panels to the composite tubing sections via the additively manufactured tube inserts. Additional fastener torque down tests were also conducted with inserts (helicoils) imbedded within the joints. Lessons learned are also included and discussed.

  1. Design and fabrication of inner-selective thin-film composite (TFC) hollow fiber modules for pressure retarded osmosis (PRO)

    KAUST Repository

    Wan, Chun Feng

    2016-08-03

    Pressure retarded osmosis (PRO) is a promising technology to harvest the renewable osmotic energy from salinity gradients. There are great progresses in the fabrication of PRO membranes in the last decade. Thin-film composite (TFC) hollow fibers have been widely studied and demonstrated superior performance. However, the lack of effective TFC hollow fiber modules hinders the commercialization of the PRO technology. Knowledge and experiences to fabricate TFC hollow fiber modules remain limited in the open literature. In this study, we aim to reveal the engineering and science on how to fabricate TFC hollow fiber modules including the formation of inner-selective polyamide layers and the repair of leakages. TFC-PES hollow fiber modules with 30% and 50% packing densities have been successfully fabricated, showing peak power densities of 20.0 W/m2 and 19.4 W/m2, respectively, at 20 bar using 1 M NaCl solution and DI water as feeds. The modules may be damaged during handling and high pressure testing. The repaired modules have a power density of 18.2 W/m2, 91% of the power densities of the undamaged ones. This study would make up the gap between TFC membrane fabrication and TFC membrane module fabrication in the membrane industry. © 2016 Elsevier B.V.

  2. Polyoxotungstate nanoclusters supported on silica as an efficient solid-phase microextraction fiber of polycyclic aromatic hydrocarbons

    International Nuclear Information System (INIS)

    Abolghasemi, Mir Mahdi; Yousefi, Vahid; Rafiee, Ezzat

    2014-01-01

    A highly porous silica-supported tungstophosphoric acid (PW) nanocluster was prepared for use in solid-phase microextraction (SPME) of polycyclic aromatic hydrocarbons (PAHs). The PWs represent a class of discrete transition metal-oxide nanoclusters and their structures resemble discrete fragments of metal-oxide structures of definite size and shape. Transition metal-oxide nanoclusters display large structural diversity, and their monodisperse sizes can be tuned from several Ångstroms up to 10 nm. The highly porous silica-supported tungstophosphoric acid nanocluster material is found to be capable of efficiently extracting PAHs from aqueous sample solutions. The nanomaterial was immobilized on a stainless steel wire for fabrication of the SPME fiber. Following thermal desorption, the PAHs were quantified by GC-MS. Analytical merits include limits of detection that range from 0.02 to 0.1 pg mL −1 and a dynamic range as wide as from 0.001 to 100 ng mL −1 . Under optimum conditions, the repeatability for one fiber (n = 3), expressed as the relative standard deviation, is between 4.3 % and 8.6 %. The method is simple, rapid, and inexpensive. The thermal stability of the fiber and the high relative recovery make this method superior to conventional methods of extraction. (author)

  3. Fabrication and capacitive characteristics of conjugated polymer composite p-polyaniline/n-WO{sub 3} heterojunction

    Energy Technology Data Exchange (ETDEWEB)

    Amaechi, C.I.; Asogwa, P.U.; Ekwealor, A.B.C. [University of Nigeria, Department of Physics and Astronomy, Nsukka, Enugu State (Nigeria); Osuji, R.U.; Ezema, F.I. [University of Nigeria, Department of Physics and Astronomy, Nsukka, Enugu State (Nigeria); iThemba LABS-National Research Foundation, Nanosciences African Network (NANOAFNET), Somerset West, Western Cape Province (South Africa); University of South Africa (UNISA), UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology, College of Graduate Studies, Pretoria (South Africa); Maaza, M. [iThemba LABS-National Research Foundation, Nanosciences African Network (NANOAFNET), Somerset West, Western Cape Province (South Africa); University of South Africa (UNISA), UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology, College of Graduate Studies, Pretoria (South Africa)

    2014-11-15

    A nanocrystalline and porous p-polyaniline/n-WO{sub 3} dissimilar heterojunction at ambient temperature is reported. The high-quality and well-reproducible conjugated polymer composite films have been fabricated by oxidative polymerization of anilinium ion on predeposited WO{sub 3} thin film by chemical bath deposition followed by thermal annealing at 573 K for 1 h. Atomic force microscopy (AFM) analyses reveal a homogenous but irregular cluster of faceted spherically shaped grains with pores. The scanning electron microscopy confirms the porous network of grains, which is in good agreement with the AFM result. The optical absorption analysis of polyaniline/WO{sub 3} hybrid films showed that direct optical transition exist in the photon energy range 3.50-4.00 eV with bandgap of 3.70 eV. The refractive index developed peak at 445 nm in the dispersion region while the high-frequency dielectric constant, ε {sub ∞}, and the carrier concentration to effective mass ratio, N/m{sup *}, was found to be 1.58 and 1.10 x 10{sup 39} cm{sup -3}, respectively. The temperature dependence of electrical resistivity of the deposited films follows the semiconductor behavior while the C-V characteristics (Mott-Schottky plots) show that the flat band potential was -791 and 830 meV/SCE for WO{sub 3} and polyaniline. (orig.)

  4. Fabrication of Composite Microneedle Array Electrode for Temperature and Bio-Signal Monitoring

    Directory of Open Access Journals (Sweden)

    Yiwei Sun

    2018-04-01

    Full Text Available Body temperature and bio-signals are important health indicators that reflect the human health condition. However, monitoring these indexes is inconvenient and time-consuming, requires various instruments, and needs professional skill. In this study, a composite microneedle array electrode (CMAE was designed and fabricated. It simultaneously detects body temperature and bio-signals. The CMAE consists of a 6 × 6 microneedles array with a height of 500 μm and a base diameter of 200 μm. Multiple insertion experiments indicate that the CMAE possesses excellent mechanical properties. The CMAE can pierce porcine skin 100 times without breaking or bending. A linear calibration relationship between temperature and voltage are experimentally obtained. Armpit temperature (35.8 °C and forearm temperature (35.3 °C are detected with the CMAE, and the measurements agree well with the data acquired with a clinical thermometer. Bio-signals including EII, ECG, and EMG are recorded and compared with those obtained by a commercial Ag/AgCl electrode. The CMAE continuously monitors bio-signals and is more convenient to apply because it does not require skin preparation and gel usage. The CMAE exhibits good potential for continuous and repetitive monitoring of body temperature and bio-signals.

  5. Fabrication of Composite Microneedle Array Electrode for Temperature and Bio-Signal Monitoring.

    Science.gov (United States)

    Sun, Yiwei; Ren, Lei; Jiang, Lelun; Tang, Yong; Liu, Bin

    2018-04-13

    Body temperature and bio-signals are important health indicators that reflect the human health condition. However, monitoring these indexes is inconvenient and time-consuming, requires various instruments, and needs professional skill. In this study, a composite microneedle array electrode (CMAE) was designed and fabricated. It simultaneously detects body temperature and bio-signals. The CMAE consists of a 6 × 6 microneedles array with a height of 500 μm and a base diameter of 200 μm. Multiple insertion experiments indicate that the CMAE possesses excellent mechanical properties. The CMAE can pierce porcine skin 100 times without breaking or bending. A linear calibration relationship between temperature and voltage are experimentally obtained. Armpit temperature (35.8 °C) and forearm temperature (35.3 °C) are detected with the CMAE, and the measurements agree well with the data acquired with a clinical thermometer. Bio-signals including EII, ECG, and EMG are recorded and compared with those obtained by a commercial Ag/AgCl electrode. The CMAE continuously monitors bio-signals and is more convenient to apply because it does not require skin preparation and gel usage. The CMAE exhibits good potential for continuous and repetitive monitoring of body temperature and bio-signals.

  6. Fast-dissolving core-shell composite microparticles of quercetin fabricated using a coaxial electrospray process.

    Directory of Open Access Journals (Sweden)

    Chen Li

    Full Text Available This study reports on novel fast-dissolving core-shell composite microparticles of quercetin fabricated using coaxial electrospraying. A PVC-coated concentric spinneret was developed to conduct the electrospray process. A series of analyses were undertaken to characterize the resultant particles in terms of their morphology, the physical form of their components, and their functional performance. Scanning and transmission electron microscopies revealed that the microparticles had spherical morphologies with clear core-shell structure visible. Differential scanning calorimetry and X-ray diffraction verified that the quercetin active ingredient in the core and sucralose and sodium dodecyl sulfate (SDS excipients in the shell existed in the amorphous state. This is believed to be a result of second-order interactions between the components; these could be observed by Fourier transform infrared spectroscopy. In vitro dissolution and permeation studies showed that the microparticles rapidly released the incorporated quercetin within one minute, and had permeation rates across the sublingual mucosa around 10 times faster than raw quercetin.

  7. Fabrication of superhydrophobic polyurethane/organoclay nano-structured composites from cyclomethicone-in-water emulsions

    International Nuclear Information System (INIS)

    Bayer, I.S.; Steele, A.; Martorana, P.J.; Loth, E.

    2010-01-01

    Nano-structured polyurethane/organoclay composite films were fabricated by dispersing moisture-curable polyurethanes and fatty amine/amino-silane surface modified montmorillonite clay (organoclay) in cyclomethicone-in-water emulsions. Cyclomethicone Pickering emulsions were made by emulsifying decamethylcyclopentasiloxane (D 5 ), dodecamethylcyclohexasiloxane (D 6 ) and aminofunctional siloxane polymers with water using montmorillonite particles as emulsion stabilizers. Polyurethane and organoclay dispersed emulsions were spray coated on aluminum surfaces. Upon thermosetting, water repellent self-cleaning coatings were obtained with measured static water contact angles exceeding 155 o and low contact angle hysteresis ( o ). Electron microscopy images of the coating surfaces revealed formation of self-similar hierarchical micro- and nano-scale surface structures. The surface morphology and the coating adhesion strength to aluminum substrates were found to be sensitive to the relative amounts of dispersed polyurethane and organoclay in the emulsions. The degree of superhydrophobicity was analyzed using static water contact angles as well as contact angle hysteresis measurements. Due to biocompatibility of cyclomethicones and polyurethane, developed coatings can be considered for specific bio-medical applications.

  8. Fabrication and performances of microencapsulated paraffin composites with polymethylmethacrylate shell based on ultraviolet irradiation-initiated

    Energy Technology Data Exchange (ETDEWEB)

    Wang Yi, E-mail: wangyi@lut.cn [State Key Laboratory of Gansu Advanced Non-ferrous Metal Materials, Lanzhou University of Technology, Lanzhou 730050 (China); College of Petrochemical Technology, Lanzhou University of Technology, Lanzhou 730050 (China); Shi Huan [College of Petrochemical Technology, Lanzhou University of Technology, Lanzhou 730050 (China); Xia Tiandong [State Key Laboratory of Gansu Advanced Non-ferrous Metal Materials, Lanzhou University of Technology, Lanzhou 730050 (China); Zhang Ting; Feng Huixia [College of Petrochemical Technology, Lanzhou University of Technology, Lanzhou 730050 (China)

    2012-07-16

    In order to identify the validity of fabricating microencapsulated phase change material by ultraviolet irradiation-initiated method, the paraffin wax/polymethyl methacrylate microcapsules were prepared. The structural characteristics and thermal properties of the microcapsules were also determined by various techniques. The results of differential scanning calorimetry analyses indicate that the melting and freezing temperatures and latent heats of the microcapsules are 55.8 Degree-Sign C, 50.1 Degree-Sign C and 106.9 J g{sup -1}, 112.3 J g{sup -1}, respectively. Morphology and chemical characteristic analysis indicate that the spherical microcapsules were formed with average diameter of 0.21 {mu}m and maximum microencapsulation ratio of 66 wt.% without leakage of core materials. The results of accelerated thermal cyclic test show that the microcapsules have good thermal reliability and chemical stability although they were subjected 3000 melting/freezing cycles. Based on all these results, it can be concluded that the microencapsulated paraffin composites have good potential for thermal energy storage purposes and ultraviolet irradiation-initiated method is a prominent candidate for preparing microencapsulated PCMs. - Highlights: Black-Right-Pointing-Pointer Microencapsulated paraffin with PMMA shell was synthesized via self-assembly. Black-Right-Pointing-Pointer Microcapsules with excellent properties can be prepared by UV initiated method. Black-Right-Pointing-Pointer The microencapsulation ratio is as high as 66 wt.%. Black-Right-Pointing-Pointer Thermal properties are as high as comparable with microcapsules in the literature.

  9. Fabrication and performances of microencapsulated paraffin composites with polymethylmethacrylate shell based on ultraviolet irradiation-initiated

    International Nuclear Information System (INIS)

    Wang Yi; Shi Huan; Xia Tiandong; Zhang Ting; Feng Huixia

    2012-01-01

    In order to identify the validity of fabricating microencapsulated phase change material by ultraviolet irradiation-initiated method, the paraffin wax/polymethyl methacrylate microcapsules were prepared. The structural characteristics and thermal properties of the microcapsules were also determined by various techniques. The results of differential scanning calorimetry analyses indicate that the melting and freezing temperatures and latent heats of the microcapsules are 55.8 °C, 50.1 °C and 106.9 J g −1 , 112.3 J g −1 , respectively. Morphology and chemical characteristic analysis indicate that the spherical microcapsules were formed with average diameter of 0.21 μm and maximum microencapsulation ratio of 66 wt.% without leakage of core materials. The results of accelerated thermal cyclic test show that the microcapsules have good thermal reliability and chemical stability although they were subjected 3000 melting/freezing cycles. Based on all these results, it can be concluded that the microencapsulated paraffin composites have good potential for thermal energy storage purposes and ultraviolet irradiation-initiated method is a prominent candidate for preparing microencapsulated PCMs. - Highlights: ► Microencapsulated paraffin with PMMA shell was synthesized via self-assembly. ► Microcapsules with excellent properties can be prepared by UV initiated method. ► The microencapsulation ratio is as high as 66 wt.%. ► Thermal properties are as high as comparable with microcapsules in the literature.

  10. Interface structure and properties of CNTs/Cu composites fabricated by electroless deposition and spark plasma sintering

    Science.gov (United States)

    Wang, Hu; Zhang, Zhao-Hui; Hu, Zheng-Yang; Song, Qi; Yin, Shi-Pan

    2018-01-01

    In this paper, we fabricated a novel copper matrix composites reinforced by carbon nanotubes (CNTs) using electroless deposition (ED) and spark plasma sintering technique. Microstructure, mechanical, electric conductivity, and thermal properties of the CNTs/Cu composites were investigated. The results show that a favorable interface containing C–O and O–Cu bond was formed between CNTs and matrix when the CNTs were coated with nano-Cu by ED method. Thus, we accomplished the uniformly dispersed CNTs in the CNTs/Cu powders and compacted composites, which eventually leads to the enhancement of the mechanical properties of the CNTs/Cu composites in the macro-scale environment. However, the interface structure can hinder the movement of carriers and free electrons and increase the interface thermal resistance, which leads to modest decrease of electrical and thermal conductivity of the CNTs/Cu composites.

  11. Multi-Scaled Modeling the Mechanical Properties of Tubular Composites Reinforced with Innovated 3D Weft Knitted Spacer Fabrics

    Science.gov (United States)

    Omrani, Elahe; Hasani, Hossein; Dibajian, Sayed Houssain

    2018-02-01

    Textile composites of 3D integrated spacer configurations have been recently focused by several researchers all over the world. In the present study, newly-designed tubular composites reinforced with 3D spacer weft knitted fabrics were considered and the effects of their structural parameters on some applicable mechanical properties were investigated. For this purpose, two different samples of 3D spacer weft knitted textile types in tubular form were produced on an electronic flat knitting machine, using glass/nylon hybrid yarns. Thermoset tubular-shaped composite parts were manufactured via vacuum infusion molding process using epoxy resin. The mechanical properties of the produced knitted composites in term of external static and internal hydrostatic pressures were evaluated. Resistance of the produced composites against the external static and internal hydrostatic pressures was numerically simulated using multi-scale modeling method. The finding revealed that there is acceptable correlation between experimental and theoretical results.

  12. Fabrication and Prototyping Lab

    Data.gov (United States)

    Federal Laboratory Consortium — Purpose: The Fabrication and Prototyping Lab for composite structures provides a wide variety of fabrication capabilities critical to enabling hands-on research and...

  13. GLASS FABRICATION AND PRODUCT CONSISTENCY TESTING OF LANTHANIDE BOROSILICATE FRIT X COMPOSITION FOR PLUTONIUM DISPOSITION

    Energy Technology Data Exchange (ETDEWEB)

    Marra, J

    2006-11-15

    The Department of Energy Office of Environmental Management (DOE/EM) plans to conduct the Plutonium Disposition Project at the Savannah River Site (SRS) to disposition excess weapons-usable plutonium. A plutonium glass waste form is the preferred option for immobilization of the plutonium for subsequent disposition in a geologic repository. A reference glass composition (Lanthanide Borosilicate (LaBS) Frit B) was developed during the Plutonium Immobilization Program (PIP) to immobilize plutonium in the late 1990's. A limited amount of performance testing was performed on this baseline composition before efforts to further pursue Pu disposition via a glass waste form ceased. Recent FY05 studies have further investigated the LaBS Frit B formulation as well as development of a newer LaBS formulation denoted as LaBS Frit X. The objectives of this present task were to fabricate plutonium loaded LaBS Frit X glass and perform corrosion testing to provide near-term data that will increase confidence that LaBS glass product is suitable for disposal in the Yucca Mountain Repository. Specifically, testing was conducted in an effort to provide data to Yucca Mountain Project (YMP) personnel for use in performance assessment calculations. Plutonium containing LaBS glass with the Frit X composition with a 9.5 wt% PuO{sub 2} loading was prepared for testing. Glass was prepared to support Product Consistency Testing (PCT) at Savannah River National Laboratory (SRNL). The glass was thoroughly characterized using x-ray diffraction (XRD) and scanning electron microscopy coupled with energy dispersive spectroscopy (SEM/EDS) prior to performance testing. A series of PCTs were conducted at SRNL using quenched Pu Frit X glass with varying exposed surface areas. Effects of isothermal and can-in-canister heat treatments on the Pu Frit X glass were also investigated. Another series of PCTs were performed on these different heat-treated Pu Frit X glasses. Leachates from all these PCTs

  14. Fabrication and characterization of a biodegradable Mg-2Zn-0.5Ca/1β-TCP composite.

    Science.gov (United States)

    Huang, Yan; Liu, Debao; Anguilano, Lorna; You, Chen; Chen, Minfang

    2015-09-01

    A biodegradable magnesium matrix and beta-tricalcium phosphate (β-TCP) particles reinforced composite Mg-2Zn-0.5Ca/1beta-TCP (wt.%) was fabricated for biomedical applications by the novel route of combined high shear solidification (HSS) and equal channel angular extrusion (ECAE). The as-cast composite obtained by HSS showed a fine and equiaxed grain structure with globally uniformly distributed β-TCP particles in aggregates of 2-25 μm in size. The ECAE processing at 300 °C resulted in further microstructural refinement and the improvement of β-TCP particle distribution. During ECAE, the β-TCP aggregates were broken into smaller ones or individual particles, forming a dispersion in the matrix. Such fabricated composite exhibited enhanced hardness and in vitro corrosion resistance. The enhanced hardness was attributed to both the addition of β-TCP particles and grain refinement while the development of a Ca-P rich surface layer from β-TCP during corrosion was responsible for the improvement in corrosion resistance. The composite was characterized in terms of microstructural evolution during fabrication, mechanical properties and electrochemical performance during polarization and immersion tests in a simulated body fluid. Discussions are made on the benefits of both HSS and ECAE and the mechanisms responsible for the enhanced corrosion resistance. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Investigations on mechanical and two-body abrasive wear behaviour of glass/carbon fabric reinforced vinyl ester composites

    International Nuclear Information System (INIS)

    Suresha, B.; Kumar, Kunigal N. Shiva

    2009-01-01

    The aim of the research article is to study the mechanical and two-body abrasive wear behaviour of glass/carbon fabric reinforced vinyl ester composites. The measured wear volume loss increases with increase in abrading distance/abrasive particle size. However, the specific wear rate decreases with increase in abrading distance and decrease in abrasive particle size. The results showed that the highest specific wear rate is for glass fabric reinforced vinyl ester composite with a value of 10.89 x 10 -11 m 3 /Nm and the lowest wear rate is for carbon fabric reinforced vinyl ester composite with a value of 4.02 x 10 -11 m 3 /Nm. Mechanical properties were evaluated and obtained values are compared with the wear behaviour. The worn surface features have been examined using scanning electron microscope (SEM). Photomicrographs of the worn surfaces revealed higher percentage of broken glass fiber as compared to carbon fiber. Also better interfacial adhesion between carbon and vinyl ester in carbon reinforced vinyl ester composite was observed.

  16. Microstructure, Hardness, and Corrosion Behavior of TiC-Duplex Stainless Steel Composites Fabricated by Spark Plasma Sintering

    Science.gov (United States)

    Han, Ying; Zhang, Wei; Sun, Shicheng; Chen, Hua; Ran, Xu

    2017-08-01

    Duplex stainless steel composites with various weight fractions of TiC particles are prepared by spark plasma sintering. Ferritic 434L and austenitic 316L stainless steel powders are premixed in a 50:50 weight ratio and added with 3-9 wt.% TiC. The compacts are sintered in the solid state under vacuum conditions at 1223 K for 5 min. The effects of TiC content on the microstructure, hardness, and corrosion resistance of duplex stainless steel composites fabricated by powder metallurgy are evaluated. The results indicate that the TiC particulates as reinforcements can be distributed homogeneously in the steel matrix. Densification of sintered composites decreases with increasing TiC content. M23C6 carbide precipitates along grain boundary, and its neighboring Cr-Mo-depleted region is formed in the sintered microstructure, which can be eliminated subsequently with appropriate heat treatment. With the addition of TiC, the hardness of duplex stainless steel fabricated by powder metallurgy can be markedly enhanced despite increased porosity in the composites. However, TiC particles increase the corrosion rate and degrade the passivation capability, particularly for the composite with TiC content higher than 6 wt.%. Weakened metallurgical bonding in the composite with high TiC content provides the preferred sites for pitting nucleation and/or dissolution.

  17. Ultrafine-grained porous titanium and porous titanium/magnesium composites fabricated by space holder-enabled severe plastic deformation

    Energy Technology Data Exchange (ETDEWEB)

    Qi, Yuanshen, E-mail: yuanshen.qi@monash.edu [Centre for Advanced Hybrid Materials, Department of Materials Engineering, Monash University, Clayton, Victoria 3800 (Australia); Contreras, Karla G. [Monash Institute of Medical Engineering, Faculty of Engineering, Monash University, Clayton, Victoria 3800 (Australia); Jung, Hyun-Do [Liquid Processing & Casting Technology R& D Group, Korea Institute of Industrial Technology, Incheon 406-840 (Korea, Republic of); Department of Materials Science and Engineering, Seoul National University, Seoul 151-742 (Korea, Republic of); Kim, Hyoun-Ee [Department of Materials Science and Engineering, Seoul National University, Seoul 151-742 (Korea, Republic of); Advanced Institutes of Convergence Technology, Seoul National University, Gwanggyo, Yeongtong-gu, Suwon-si, Gyeonggi-do 443-270 (Korea, Republic of); Lapovok, Rimma [Centre for Advanced Hybrid Materials, Department of Materials Engineering, Monash University, Clayton, Victoria 3800 (Australia); Estrin, Yuri, E-mail: yuri.estrin@monash.edu [Centre for Advanced Hybrid Materials, Department of Materials Engineering, Monash University, Clayton, Victoria 3800 (Australia); Laboratory of Hybrid Nanostructured Materials, NUST MISiS, Moscow 119490 (Russian Federation)

    2016-02-01

    Compaction of powders by equal channel angular pressing (ECAP) using a novel space holder method was employed to fabricate metallic scaffolds with tuneable porosity. Porous Ti and Ti/Mg composites with 60% and 50% percolating porosity were fabricated using powder blends with two kinds of sacrificial space holders. The high compressive strength and good ductility of porous Ti and porous Ti/Mg obtained in this way are believed to be associated with the ultrafine grain structure of the pore walls. To understand this, a detailed electron microscopy investigation was employed to analyse the interface between Ti/Ti and Ti/Mg particles, the grain structures in Ti particles and the topography of pore surfaces. It was found that using the proposed compaction method, high quality bonding between particles was obtained. Comparing with other powder metallurgy methods to fabricate Ti with an open porous structure, where thermal energy supplied by a laser beam or high temperature sintering is essential, the ECAP process conducted at a relatively low temperature of 400 °C was shown to produce unique properties. - Highlights: • Porous Ti and porous Ti/Mg composite scaffolds were fabricated successfully. • Space holder-enabled severe plastic deformation was first used in this application. • Silicon particles as sacrificial space holders were used for the first time. • Ultrafine-grained microstructure and good bonding between particles were obtained. • Good preosteoblast cell response to as-manufactured porous Ti was achieved.

  18. Ultrafine-grained porous titanium and porous titanium/magnesium composites fabricated by space holder-enabled severe plastic deformation

    International Nuclear Information System (INIS)

    Qi, Yuanshen; Contreras, Karla G.; Jung, Hyun-Do; Kim, Hyoun-Ee; Lapovok, Rimma; Estrin, Yuri

    2016-01-01

    Compaction of powders by equal channel angular pressing (ECAP) using a novel space holder method was employed to fabricate metallic scaffolds with tuneable porosity. Porous Ti and Ti/Mg composites with 60% and 50% percolating porosity were fabricated using powder blends with two kinds of sacrificial space holders. The high compressive strength and good ductility of porous Ti and porous Ti/Mg obtained in this way are believed to be associated with the ultrafine grain structure of the pore walls. To understand this, a detailed electron microscopy investigation was employed to analyse the interface between Ti/Ti and Ti/Mg particles, the grain structures in Ti particles and the topography of pore surfaces. It was found that using the proposed compaction method, high quality bonding between particles was obtained. Comparing with other powder metallurgy methods to fabricate Ti with an open porous structure, where thermal energy supplied by a laser beam or high temperature sintering is essential, the ECAP process conducted at a relatively low temperature of 400 °C was shown to produce unique properties. - Highlights: • Porous Ti and porous Ti/Mg composite scaffolds were fabricated successfully. • Space holder-enabled severe plastic deformation was first used in this application. • Silicon particles as sacrificial space holders were used for the first time. • Ultrafine-grained microstructure and good bonding between particles were obtained. • Good preosteoblast cell response to as-manufactured porous Ti was achieved.

  19. The fabrication of iron oxide nanoparticle-nanofiber composites by electrospinning and their applications in tissue engineering.

    Science.gov (United States)

    Mortimer, Chris J; Wright, Chris J

    2017-07-01

    This paper reviews the use of iron oxide nanoparticle-nanofiber composites in tissue engineering with a focus on the electrospinning technique. Electrospinning is an established method of scaffold fabrication offering a number of key advantages which include its facile nature, with electrospun materials offering a high surface area to volume ratio, potential for the release of drugs and antimicrobials, controllable fiber diameters and high porosity and permeability. A number of different techniques for the preparation of iron oxide nanoparticles including their functionalization are discussed along with their applications in the biomedical field. The review then focusses on the fabrication of nanoparticle-nanofiber composite scaffolds formed using electrospinning. The advantages and disadvantages of current fabrication techniques are discussed including the fabrication of nanofibers using pre-synthesized nanoparticles and post-treatment synthesized nanoparticles. We demonstrate that emerging in-situ synthesis techniques show promise by offering a reduced number of steps and simpler procedures for the production of magnetic scaffolds. These scaffolds have a number of applications in tissue engineering, allowing for improved bone and tissue repair. Copyright © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Hot consolidated all-PP composites from textile fabrics composed of isotactic PP filaments with different degrees of orientation

    Directory of Open Access Journals (Sweden)

    2007-12-01

    Full Text Available Self-reinforced polypropylene composites (SRPPC were hot pressed from textile layers (carded mat, knitted fabrics at three different temperatures (160, 165 and 170°C by setting a constant pressure (6 MPa and constant holding time (2 min. Both textiles consist of two kinds of isotactic polypropylene (iPP fibers differing in their orientation. In these compositions the highly oriented iPP works as reinforcement and the less oriented one fulfills the role of the matrix after hot consolidation. Two textile assemblies, viz. carded (also needle punched mats and knitted fabrics were hot pressed; and the properties of the resultant SRPPC plates were investigated under tensile and falling weight impact conditions. The microstructure of the SRPPC was analyzed by light microscopy using polished sections and by SEM using cut surfaces.

  1. Ras acylation, compartmentalization and signaling nanoclusters (Review)

    OpenAIRE

    HENIS, YOAV I.; HANCOCK, JOHN F.; PRIOR, IAN A.

    2008-01-01

    Ras proteins have become paradigms for isoform- and compartment-specific signaling. Recent work has shown that Ras isoforms are differentially distributed within cell surface signaling nanoclusters and on endomembranous compartments. The critical feature regulating Ras protein localization and isoform-specific functions is the C-terminal hypervariable region (HVR). In this review we discuss the differential post-translational modifications and reversible targeting functions of Ras isoform HVR...

  2. Fabrication of lithium titanate/graphene composites with high rate capability as electrode materials for hybrid electrochemical supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Rong, E-mail: xuerongsmile@qq.com; Yan, Jingwang, E-mail: yanjw@dicp.ac.cn; Jiang, Liang, E-mail: jiangliang@dicp.ac.cn; Yi, Baolian, E-mail: blyi@dicp.ac.cn

    2015-06-15

    A lithium titanate (Li{sub 4}Ti{sub 5}O{sub 12})/graphene composite (LTO/graphene) is fabricated with a one-pot sol–gel method. Graphite oxide is dispersed in an aqueous solution of lithium acetate and tetrabutyl titanate followed by heat treatment in H{sub 2}/Ar. The LTO/graphene composite with reduced aggregation and improved homogeneity is investigated as an anode material for electrochemical capacitors. Electron transport is improved by the conductive graphene network in the insulating Li{sub 4}Ti{sub 5}O{sub 12} particles. The charge transfer resistance at the particle/electrolyte interface is reduced from 83.1 Ω to 55.4 Ω. The specific capacity of LTO/graphene composite is 126 mAh g{sup −1} at 20C. The energy density and power density of a hybrid electrochemical supercapacitor with a LTO/graphene negative electrode and an activated carbon positive electrode are 120.8 Wh kg{sup −1} and 1.5 kW kg{sup −1}, respectively, which is comparable to that of conventional electrochemical double layer capacitors (EDLCs). The LTO/graphene composite fabricated by the one-pot sol–gel method is a promising anode material for hybrid electrochemical supercapacitors. - Highlights: • A Li{sub 4}Ti{sub 5}O{sub 12}/graphene composite was fabricated with a one-pot sol–gel method. • The Li{sub 4}Ti{sub 5}O{sub 12}/graphene composite showed a reduced aggregation and an improved homogeneity. • The Li{sub 4}Ti{sub 5}O{sub 12}/graphene based hybrid supercapacitor exhibited higher energy and power densities.

  3. Assembly, Structure and Properties of DNA Programmable Nanoclusters

    Science.gov (United States)

    Chi, Cheng

    Finite size nanoclusters can be viewed as a nanoscale analogue of molecules. Just as molecules, synthesized from atoms, give access to new properties, clusters composed of nanoparticles modulate of their functional properties of nanoparticles. In contrast to synthetic chemistry which is a mature field, the creation of nanoscale clusters with well-defined architectures is a new and challenging area of research. My work explores how to assemble model systems of nanoclusters using DNA-programmable interparticle linkages. The simplest clusters of two particles, dimers, allow one to investigate fundamental effects in these systems. Such clusters serve as a versatile platform to understand DNA-mediated interactions, especially in the non-trivial regime where the nanoparticle and DNA chains are comparable in size. I systematically studied a few fundamental questions as follows: Firstly, we examined the structure of nanoparticle dimers in detail by a combination of X-ray scattering experiments and molecular simulations. We found that, for a given DNA length, the interparticle separation within the dimer is controlled primarily by the number of linking DNA. We summarized our findings in a simple model that captures the interplay of the number of DNA bridges, their length, the particle's curvature and the excluded volume effects. We demonstrated the applicability of the model to our results, without any free parameters. As a consequence, the increase of dimer separation with increasing temperature can be understood as a result of changing the number of connecting DNA. Later, we investigated the self-assembly process of DNA-functionalized particles in the presence of various lengths of the DNA linkage strands using 3 different pathways. We observed a high yield of dimer formation when significantly long linkers were applied. Small Angle X-ray Scattering revealed two configurations of the small clusters by different pathways. In one case, the interparticle distance increases

  4. Design, ancillary testing, analysis and fabrication data for the advanced composite stabilizer for Boeing 737 aircraft. Volume 1: Technical summary

    Science.gov (United States)

    Aniversario, R. B.; Harvey, S. T.; Mccarty, J. E.; Parsons, J. T.; Peterson, D. C.; Pritchett, L. D.; Wilson, D. R.; Wogulis, E. R.

    1983-01-01

    The horizontal stabilizer of the 737 transport was redesigned. Five shipsets were fabricated using composite materials. Weight reduction greater than the 20% goal was achieved. Parts and assemblies were readily produced on production-type tooling. Quality assurance methods were demonstrated. Repair methods were developed and demonstrated. Strength and stiffness analytical methods were substantiated by comparison with test results. Cost data was accumulated in a semiproduction environment. FAA certification was obtained.

  5. GLASS FABRICATION AND PRODUCT CONSISTENCY TESTING OF LANTHANIDE BOROSHILICATE FRIT X COMPOSITION FOR PLUTONIUM DISPOSITION

    Energy Technology Data Exchange (ETDEWEB)

    Marra, J

    2006-11-21

    The Department of Energy Office of Environmental Management (DOE/EM) plans to conduct the Plutonium Disposition Project at the Savannah River Site (SRS) to disposition excess weapons-usable plutonium. A plutonium glass waste form is the preferred option for immobilization of the plutonium for subsequent disposition in a geologic repository. A reference glass composition (Lanthanide Borosilicate (LaBS) Frit B) was developed during the Plutonium Immobilization Program (PIP) to immobilize plutonium in the late 1990's. A limited amount of performance testing was performed on this baseline composition before efforts to further pursue Pu disposition via a glass waste form ceased. Recent FY05 studies have further investigated the LaBS Frit B formulation as well as development of a newer LaBS formulation denoted as LaBS Frit X. The objectives of this present task were to fabricate plutonium loaded LaBS Frit X glass and perform corrosion testing to provide near-term data that will increase confidence that LaBS glass product is suitable for disposal in the Yucca Mountain Repository. Specifically, testing was conducted in an effort to provide data to Yucca Mountain Project (YMP) personnel for use in performance assessment calculations. Plutonium containing LaBS glass with the Frit X composition with a 9.5 wt% PuO{sub 2} loading was prepared for testing. Glass was prepared to support Product Consistency Testing (PCT) at Savannah River National Laboratory (SRNL). The glass was thoroughly characterized using x-ray diffraction (XRD) and scanning electron microscopy coupled with energy dispersive spectroscopy (SEM/EDS) prior to performance testing. A series of PCTs were conducted at SRNL using quenched Pu Frit X glass with varying exposed surface areas. Effects of isothermal and can-in-canister heat treatments on the Pu Frit X glass were also investigated. Another series of PCTs were performed on these different heat-treated Pu Frit X glasses. Leachates from all these PCTs

  6. Embedded Si/Graphene Composite Fabricated by Magnesium-Thermal Reduction as Anode Material for Lithium-Ion Batteries

    Science.gov (United States)

    Zhu, Jiangliu; Ren, Yurong; Yang, Bo; Chen, Wenkai; Ding, Jianning

    2017-12-01

    Embedded Si/graphene composite was fabricated by a novel method, which was in situ generated SiO2 particles on graphene sheets followed by magnesium-thermal reduction. The tetraethyl orthosilicate (TEOS) and flake graphite was used as original materials. On the one hand, the unique structure of as-obtained composite accommodated the large volume change to some extent. Simultaneously, it enhanced electronic conductivity during Li-ion insertion/extraction. The MR-Si/G composite is used as the anode material for lithium ion batteries, which shows high reversible capacity and ascendant cycling stability reach to 950 mAh·g-1 at a current density of 50 mA·g-1 after 60 cycles. These may be conducive to the further advancement of Si-based composite anode design.

  7. Evaluation of a non-woven fabric coated with a chitosan bi-layer composite for wound dressing.

    Science.gov (United States)

    Liu, Bai-Shuan; Yao, Chun-Hsu; Fang, Shr-Shin

    2008-05-13

    This study presents a novel design of an easily stripped bi-layer composite that consists of an upper layer of a soybean protein non-woven fabric coated with a lower layer, a genipin-crosslinked chitosan film, as a wound dressing material. This study examines the in vitro properties of the genipin-crosslinked chitosan film and the bi-layer composite. Furthermore, in vivo experiments are conducted to study wounds treated with the composite in a rat model. Experimental results show that the degree of crosslinking and the in vitro degradation rate of the genipin-crosslinked chitosan films can be controlled by varying the genipin contents. In addition, the genipin contents should exceed 0.025 wt.-% of the chitosan-based material if complete crosslinking reactions between genipin and chitosan molecules are required. Water contact angle analysis shows that the genipin-crosslinked chitosan film is not highly hydrophilic; therefore, the genipin-crosslinked chitosan layer is not entangled with the soybean protein non-woven fabric, which forms an easily stripped interface layer between them. Furthermore, this new wound dressing material provides adequate moisture, thereby minimizing the risk of wound dehydration, and exhibits good mechanical properties. The in vivo histological assessment results reveal that epithelialization and reconstruction of the wound are achieved by covering the wound with the composite, and the composite is easily stripped from the wound surface without damaging newly regenerated tissue.

  8. Fabrication and Performance Test of Aluminium Alloy-Rice Husk Ash Hybrid Metal Matrix Composite as Industrial and Construction Material

    Directory of Open Access Journals (Sweden)

    Md. Rahat Hossain

    2017-12-01

    Full Text Available Aluminium matrix composites (AMCs used extensively in various engineering fields due to their exceptional mechanical properties. In this present study, aluminium matrix composites (AMCs such as aluminium alloy (A356 reinforced with rice husk ash particles (RHA are made to explore the possibilities of reinforcing aluminium alloy. The stir casting method was applied to produce aluminium alloy (A356 reinforced with various amounts of (2%, 4%, and 6% rice husk ash (RHA particles. Physical treatment was carried out before the rice husk ash manufacturing process. The effect of mechanical strength of the fabricated hybrid composite was investigated. Therefore, impact test, tensile stress, compressive stress, and some other tests were carried out to analyse the mechanical properties. From the experimental results, it was found that maximum tensile, and compressive stress were found at 6% rice husk ash (RHA and aluminium matrix composites (AMCs. In future, the optimum percentages of rice husk ash (RHA to fabricate the hybrid composites will be determined. Also, simulation by finite element method (FEM will be applied for further investigation.

  9. Passivation of cobalt nanocluster assembled thin films with hydrogen

    DEFF Research Database (Denmark)

    Romero, C.P.; Volodin, A.; Di Vece, M.

    2012-01-01

    The effect of hydrogen passivation on bare and Pd capped cobalt nanocluster assembled thin films was studied with Rutherford backscattering spectrometry (RBS) and magnetic force microscopy (MFM) after exposure to ambient conditions. The nanoclusters are produced in a laser vaporization cluster...

  10. Synthesis and characterization of mixed ligand chiral nanoclusters

    KAUST Repository

    Guven, Zekiye P.

    2016-06-22

    Chiral mixed ligand silver nanoclusters were synthesized in the presence of a chiral and an achiral ligand. While the chiral ligand led mostly to the formation of nanoparticles, the presence of the achiral ligand drastically increased the yield of nanoclusters with enhanced chiral properties. © 2016 The Royal Society of Chemistry.

  11. Fabrication of AZ31/MWCNTs Surface Metal Matrix Composites by Friction Stir Processing: Investigation of Microstructure and Mechanical Properties

    Science.gov (United States)

    Arab, Seyed Mohammad; Zebarjad, Seyed Mojtaba; Jahromi, Seyed Ahmad Jenabali

    2017-11-01

    The surface metal matrix composites of AZ31 Mg alloy reinforced with multiwall carbon nanotubes (MWCNTs) have been fabricated through the friction stir processing by a conventional and two stepped tools. The microstructure and mechanical properties of fabricated composites were studied by optical and electron microscopy, microhardness and tensile tests, respectively. The processing has developed a fine-grain structure along with good distribution of reinforcements. The hardness and tensile strength of fabricated MWCNT/AZ31 composites are generally higher than as-received and FSPed samples. The accumulative effect of grain refinement and reinforcing nanotubes is assumed to be the reason for increasing the ductility after friction stir processing. The hardness is nearly doubled for FSPed samples and some more for nanocomposites compared with the as-received sample. The elongation of nanocomposites is about two times greater than that of the as-rolled sample. The speed ratio, pass number and CNT amount are three important factors influencing the resulting microstructure and mechanical properties. The stepped tools also give a more uniform distribution of reinforcement and higher grain refinement.

  12. [Energy dispersive spectrum analysis of surface compositions of selective laser melting cobalt-chromium alloy fabricated by different processing parameters].

    Science.gov (United States)

    Qian, Liang; Zeng, Li; Wei, Bin; Gong, Yao

    2015-06-01

    To fabricate selective laser melting cobalt-chromium alloy samples by different processing parameters, and to analyze the changes of energy dispersive spectrum(EDS) on their surface. Nine groups were set up by orthogonal experimental design according to different laser powers,scanning speeds and powder feeding rates(laser power:2500-3000 W, scanning speed: 5-15 mm/s, powder feeding rate: 3-6 r/min). Three cylinder specimens(10 mm in diameter and 3 mm in thickness) were fabricated in each group through Rofin DL 035Q laser cladding system using cobalt-chromium alloy powders which were developed independently by our group.Their surface compositions were then measured by EDS analysis. Results of EDS analysis of the 9 groups fabricated by different processing parameters(Co:62.98%-67.13%,Cr:25.56%-28.50%,Si:0.49%-1.23%) were obtained. They were similar to the compositions of cobalt-chromium alloy used in dental practice. According to EDS results, the surface compositions of the selective laser melting cobalt-chromium alloy samples are stable and controllable, which help us gain a preliminary sight into the range of SLM processing parameters. Supported by "973" Program (2012CB910401) and Research Fund of Science and Technology Committee of Shanghai Municipality (12441903001 and 13140902701).

  13. Fabrication of Nano-CeO2 and Application of Nano-CeO2 in Fe Matrix Composites

    International Nuclear Information System (INIS)

    Tiebao, W.; Chunxiang, C.; Xiaodong, W.; Guobin, L.

    2010-01-01

    It is expatiated that nano-CeO2 is fabricated by the direct sedimentation method. The components and particles diameter of nano-CeO2 powders are analyzed by XRD and SEM . The thermodynamic analysis and acting mechanism of nano-CeO2 with Al in Fe matrix composites are researched, which shows that the reaction is generated between CeO2 and Al in the composite, that is, 3CeO2+4Al - 2Al2O3+3[Ce], which obtains Al2O3 and active [Ce] during the sintering process. The active [Ce] can improve the performance of CeO2/Fe matrix composites. The suitable amount of CeO2 is about 0.05% in CeO2/Fe matrix composites. SEM fracture analysis shows that the toughness sockets in nano-CeO2/Fe matrix composites are more than those in no-added nano-CeO2 composites, which can explain that adding nano-CeO2 into Fe matrix composite, the toughness of the composite is improved significantly. Applied nano-CeO2 to Fe matrix diamond saw blades shows that Fe matrix diamond saw blade is sharper and of longer cutting life than that with no-added nano-CeO2.

  14. Structure and properties of short fiber reinforced polymer composite and hybrid composite fabricated by injection molding process

    OpenAIRE

    UAWONGSUWAN, PUTINUN

    2015-01-01

    Short fiber reinforced polymer composites have found extensive applications in many fields due to their low cost, easy processing and superior mechanical properties over the neat thermoplastics. For interpreting the mechanical properties of composite by several variable parameters, additional measurements are required when changes occur in the composite system variables. Thus, experiments may be time consuming and cost prohibitive. Therefore, theoretical models of determining composite proper...

  15. Sonochemical fabrication of petal array-like copper/nickel oxide composite foam as a pseudocapacitive material for energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Karthik, Namachivayam; Edison, Thomas Nesakumar Jebakumar Immanuel [School of Chemical Engineering, Yeungnam University, Gyeongsan 712-749 (Korea, Republic of); Sethuraman, Mathur Gopalakrishnan, E-mail: mgsethu@gmail.com [Department of Chemistry, Gandhigram Rural Institute – Deemed University, Gandhigram, 624 302, Dindigul District, Tamil Nadu (India); Lee, Yong Rok, E-mail: yrlee@yu.ac.kr [School of Chemical Engineering, Yeungnam University, Gyeongsan 712-749 (Korea, Republic of)

    2017-02-28

    Highlights: • A composite Ni foam textured with Cu particles was fabricated by a sonication method. • The foam can be used as a pseudocapacitive material for energy storage applications. • The foam has a high specific capacitance of 1773 F g{sup −1} at a scan rate of 5 mV s{sup −1}. - Abstract: Copper/nickel oxide composite foam (Cu/Ni) with petal array-like textures were successfully fabricated via a facile sonochemical approach, and its applications as a pseudocapacitive material for energy storage were examined. The nickel foam was immersed into a mixture of copper chloride (CuCl{sub 2}) and hydrochloric acid (HCl) and subsequently sonicated for 30 min at 60 °C. As a result of galvanic replacement, nickel was oxidized while copper was reduced, and the walls of the nickel foam were coated with copper particles. Studies using field emission scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopic analyses confirmed the morphology and chemical structure of the as-obtained Cu/Ni oxide composite foam. The supercapacitive performance of the as-fabricated Cu/Ni oxide composite foam was evaluated in 2 M KOH by employing cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy analyses. Cyclic voltammograms revealed that the Cu/Ni oxide composite foam exhibited pseudocapacitive behavior and delivered a high specific capacitance of 1773 F g{sup −1} at a scan rate of 5 mV s{sup −1}. This improvement may be attributed to the morphology, surface functionalization with heteroatoms, hydrogen evolution, and high conductivity, along with the low resistance due to short path lengths for electron transportation.

  16. Gradients of Rac1 Nanoclusters Support Spatial Patterns of Rac1 Signaling.

    Science.gov (United States)

    Remorino, Amanda; De Beco, Simon; Cayrac, Fanny; Di Federico, Fahima; Cornilleau, Gaetan; Gautreau, Alexis; Parrini, Maria Carla; Masson, Jean-Baptiste; Dahan, Maxime; Coppey, Mathieu

    2017-11-14

    Rac1 is a small RhoGTPase switch that orchestrates actin branching in space and time and protrusion/retraction cycles of the lamellipodia at the cell front during mesenchymal migration. Biosensor imaging has revealed a graded concentration of active GTP-loaded Rac1 in protruding regions of the cell. Here, using single-molecule imaging and super-resolution microscopy, we show an additional supramolecular organization of Rac1. We find that Rac1 partitions and is immobilized into nanoclusters of 50-100 molecules each. These nanoclusters assemble because of the interaction of the polybasic tail of Rac1 with the phosphoinositide lipids PIP2 and PIP3. The additional interactions with GEFs and possibly GAPs, downstream effectors, and other partners are responsible for an enrichment of Rac1 nanoclusters in protruding regions of the cell. Our results show that subcellular patterns of Rac1 activity are supported by gradients of signaling nanodomains of heterogeneous molecular composition, which presumably act as discrete signaling platforms. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  17. First-principles calculated decomposition pathways for LiBH4 nanoclusters

    Science.gov (United States)

    Huang, Zhi-Quan; Chen, Wei-Chih; Chuang, Feng-Chuan; Majzoub, Eric H.; Ozoliņš, Vidvuds

    2016-05-01

    We analyze thermodynamic stability and decomposition pathways of LiBH4 nanoclusters using grand-canonical free-energy minimization based on total energies and vibrational frequencies obtained from density-functional theory (DFT) calculations. We consider (LiBH4)n nanoclusters with n = 2 to 12 as reactants, while the possible products include (Li)n, (B)n, (LiB)n, (LiH)n, and Li2BnHn; off-stoichiometric LinBnHm (m ≤ 4n) clusters were considered for n = 2, 3, and 6. Cluster ground-state configurations have been predicted using prototype electrostatic ground-state (PEGS) and genetic algorithm (GA) based structural optimizations. Free-energy calculations show hydrogen release pathways markedly differ from those in bulk LiBH4. While experiments have found that the bulk material decomposes into LiH and B, with Li2B12H12 as a kinetically inhibited intermediate phase, (LiBH4)n nanoclusters with n ≤ 12 are predicted to decompose into mixed LinBn clusters via a series of intermediate clusters of LinBnHm (m ≤ 4n). The calculated pressure-composition isotherms and temperature-pressure isobars exhibit sloping plateaus due to finite size effects on reaction thermodynamics. Generally, decomposition temperatures of free-standing clusters are found to increase with decreasing cluster size due to thermodynamic destabilization of reaction products.

  18. Atomic characterization of Si nanoclusters embedded in SiO2 by atom probe tomography

    Science.gov (United States)

    2011-01-01

    Silicon nanoclusters are of prime interest for new generation of optoelectronic and microelectronics components. Physical properties (light emission, carrier storage...) of systems using such nanoclusters are strongly dependent on nanostructural characteristics. These characteristics (size, composition, distribution, and interface nature) are until now obtained using conventional high-resolution analytic methods, such as high-resolution transmission electron microscopy, EFTEM, or EELS. In this article, a complementary technique, the atom probe tomography, was used for studying a multilayer (ML) system containing silicon clusters. Such a technique and its analysis give information on the structure at the atomic level and allow obtaining complementary information with respect to other techniques. A description of the different steps for such analysis: sample preparation, atom probe analysis, and data treatment are detailed. An atomic scale description of the Si nanoclusters/SiO2 ML will be fully described. This system is composed of 3.8-nm-thick SiO layers and 4-nm-thick SiO2 layers annealed 1 h at 900°C. PMID:21711666

  19. Atomic characterization of Si nanoclusters embedded in SiO2 by atom probe tomography

    Directory of Open Access Journals (Sweden)

    Gourbilleau Fabrice

    2011-01-01

    Full Text Available Abstract Silicon nanoclusters are of prime interest for new generation of optoelectronic and microelectronics components. Physical properties (light emission, carrier storage... of systems using such nanoclusters are strongly dependent on nanostructural characteristics. These characteristics (size, composition, distribution, and interface nature are until now obtained using conventional high-resolution analytic methods, such as high-resolution transmission electron microscopy, EFTEM, or EELS. In this article, a complementary technique, the atom probe tomography, was used for studying a multilayer (ML system containing silicon clusters. Such a technique and its analysis give information on the structure at the atomic level and allow obtaining complementary information with respect to other techniques. A description of the different steps for such analysis: sample preparation, atom probe analysis, and data treatment are detailed. An atomic scale description of the Si nanoclusters/SiO2 ML will be fully described. This system is composed of 3.8-nm-thick SiO layers and 4-nm-thick SiO2 layers annealed 1 h at 900°C.

  20. Fabrication and in vitro evaluation of a sponge-like bioactive-glass/gelatin composite scaffold for bone tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Nadeem, Danish [Biomaterials Engineering Group, School of Oral and Dental Sciences, University of Bristol, BS1 2LY (United Kingdom); Kiamehr, Mostafa [Biomaterials and Tissue Engineering Group, Leeds Dental Institute, University of Leeds, LS2 9LU (United Kingdom); Yang, Xuebin [Biomaterials and Tissue Engineering Group, Leeds Dental Institute, University of Leeds, LS2 9LU (United Kingdom); NIHR Leeds Musculoskeletal Biomedical Research Unit, Chapel Allerton Hospital, Leeds LS7 4SA (United Kingdom); Su, Bo, E-mail: b.su@bristol.ac.uk [Biomaterials Engineering Group, School of Oral and Dental Sciences, University of Bristol, BS1 2LY (United Kingdom)

    2013-07-01

    In this work a bioactive composite scaffold, comprised of bioactive-glass and gelatin, is introduced. Through direct foaming a sponge-like composite of a sol–gel derived bioactive-glass (70S30C; 70% SiO{sub 2}, 30% CaO) and porcine gelatin was developed for use as a biodegradable scaffold for bone tissue engineering. The composite was developed to provide a suitable alternative to synthetic polymer based scaffolds, allowing directed regeneration of bone tissue. The fabricated scaffold was characterised through X-ray microtomography, scanning electron and light microscopy demonstrating a three dimensionally porous and interconnected structure, with an average pore size (170 μm) suitable for successful cell proliferation and tissue ingrowth. Acellular bioactivity was assessed through apatite formation during submersion in simulated body fluid (SBF) whereby the rate and onset of apatite nucleation was found to be comparable to that of bioactive-glass. Modification of dehydrothermal treatment parameters induced varying degrees of crosslinking, allowing the degradation of the composite to be tailored to suit specific applications and establishing its potential for a wide range of applications. Use of genipin to supplement crosslinking by dehydrothermal treatment provided further means of modifying degradability. Biocompatibility of the composite was qualified through successful cultures of human dental pulp stem cells (HDPSCs) on samples of the composite scaffold. Osteogenic differentiation of HDPSCs and extracellular matrix deposition were confirmed through positive alkaline phosphatase staining and immunohistochemistry. - Highlights: ► Optimised composition and fabrication produced sponge-like porosity (pore size ∼ 170 μm). ► Maximum aqueous stability via dehydrothermal treatment at 145 °C, for 48 h ► Biocompatibility and osteogenic potential confirmed via successful HDPSC cultures. ► Minimal toxicity exhibited in optimally crosslinked samples (10 m

  1. Interfacial characteristics of diamond/aluminum composites with high thermal conductivity fabricated by squeeze-casting method

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Longtao, E-mail: longtaojiang@163.com [Department of Material Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Wang, Pingping [Department of Material Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Xiu, Ziyang [Skate Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Chen, Guoqin [Department of Material Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Lin, Xiu [Heilongjiang Academy of Industrial Technology, Harbin 150001 (China); Dai, Chen; Wu, Gaohui [Department of Material Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)

    2015-08-15

    In this work, aluminum matrix composites reinforced with diamond particles (diamond/aluminum composites) were fabricated by squeeze casting method. The material exhibited a thermal conductivity as high as 613 W / (m · K). The obtained composites were investigated by scanning electron microscope and transmission electron microscope in terms of the (100) and (111) facets of diamond particles. The diamond particles were observed to be homogeneously distributed in the aluminum matrix. The diamond{sub (111)}/Al interface was found to be devoid of reaction products. While at the diamond{sub (100)}/Al interface, large-sized aluminum carbides (Al{sub 4}C{sub 3}) with twin-crystal structure were identified. The interfacial characteristics were believed to be responsible for the excellent thermal conductivity of the material. - Graphical abstract: Display Omitted - Highlights: • Squeeze casting method was introduced to fabricate diamond/Al composite. • Sound interfacial bonding with excellent thermal conductivity was produced. • Diamond{sub (111)}/ aluminum interface was firstly characterized by TEM/HRTEM. • Physical combination was the controlling bonding for diamond{sub (111)}/aluminum. • The growth mechanism of Al{sub 4}C{sub 3} was analyzed by crystallography theory.

  2. Fabrication and Characterization of SnO2/Graphene Composites as High Capacity Anodes for Li-Ion Batteries

    Directory of Open Access Journals (Sweden)

    Abirami Dhanabalan

    2013-11-01

    Full Text Available Tin-oxide and graphene (TG composites were fabricated using the Electrostatic Spray Deposition (ESD technique, and tested as anode materials for Li-ion batteries. The electrochemical performance of the as-deposited TG composites were compared to heat-treated TG composites along with pure tin-oxide films. The heat-treated composites exhibited superior specific capacity and energy density than both the as-deposited TG composites and tin oxide samples. At the 70th cycle, the specific capacities of the as-deposited and post heat-treated samples were 534 and 737 mA·h/g, respectively, and the corresponding energy densities of the as-deposited and heat-treated composites were 1240 and 1760 W·h/kg, respectively. This improvement in the electrochemical performance of the TG composite anodes as compared to the pure tin oxide samples is attributed to the synergy between tin oxide and graphene, which increases the electrical conductivity of tin oxide and helps alleviate volumetric changes in tin-oxide during cycling.

  3. Influence of methyl mercaptan on the repair bond strength of composites fabricated using self-etch adhesives.

    Science.gov (United States)

    Yokokawa, Miho; Rikuta, Akitomo; Tsujimoto, Akimasa; Tsuchiya, Kenji; Shibasaki, Syo; Matsuyoshi, Saki; Miyazaki, Masashi

    2015-02-01

    The influence of methyl mercaptan on the repair bond strength of composites fabricated using self-etch adhesives was investigated. The surface free-energies were determined by measuring the contact angles of test liquids placed on composites that had been immersed in different concentrations of methyl mercaptan (0.01, 0.1, and 1.0 M). To determine the repair bond strength, self-etch adhesives were applied to the aged composite, and then newly added composites were condensed. Ten samples of each specimen were subjected to shear testing at a crosshead speed of 1.0 mm min(-1). Samples were analyzed using two-way ANOVA followed by Tukey's honestly significant difference (HSD) test. Although the dispersion force of the composites remained relatively constant, their polar force increased slightly as the concentration of methyl mercaptan increased. The hydrogen-bonding forces were significantly higher after immersion in 1.0 M methyl mercaptan, leading to higher surface-free energies. However, the repair bond strengths for the repair restorations prepared from composites immersed in 1.0 M methyl mercaptan were significantly lower than for those immersed in 0.01 and 0.10 M methyl mercaptan. Considering the results of this study, it can be concluded that the repair bond strengths of both the aged and newly added composites were affected by immersion in methyl mercaptan solutions. © 2014 Eur J Oral Sci.

  4. Effects of mechanical properties of polymer on ceramic-polymer composite thick films fabricated by aerosol deposition

    Science.gov (United States)

    Kwon, Oh-Yun; Na, Hyun-Jun; Kim, Hyung-Jun; Lee, Dong-Won; Nam, Song-Min

    2012-05-01

    Two types of ceramic-polymer composite thick films were deposited on Cu substrates by an aerosol deposition process, and their properties were investigated to fabricate optimized ceramic-based polymer composite thick films for application onto integrated substrates with the advantage of plasticity. When polymers with different mechanical properties, such as polyimide (PI) and poly(methyl methacrylate) (PMMA), are used as starting powders together with α-Al2O3 powder, two types of composite films are formed with different characteristics - surface morphologies, deposition rates, and crystallite size of α-Al2O3. Through the results of micro-Vickers hardness testing, it was confirmed that the mechanical properties of the polymer itself are associated with the performances of the ceramic-polymer composite films. To support and explain these results, the microstructures of the two types of polymer powders were observed after planetary milling and an additional modeling test was carried out. As a result, we could conclude that the PMMA powder is distorted by the impact of the Al2O3 powder, so that the resulting Al2O3-PMMA composite film had a very small amount of PMMA and a low deposition rate. In contrast, when using PI powder, the Al2O3-PI composite film had a high deposition rate due to the cracking of PI particles. Consequently, it was revealed that the mechanical properties of polymers have a considerable effect on the properties of the resulting ceramic-polymer composite thick films.

  5. Evidence for a composite organic-inorganic fabric of belemnite rostra: implication for palaeoceanography

    Science.gov (United States)

    Hoffmann, Rene; Richter, Detlev K.; Neuser, Rolf D.; Jöns, Niels; Linzmeier, Benjamin J.; Lemanis, Robert E.; Fusseis, Florian; Xiao, Xianghui; Immenhauser, Adrian

    2017-04-01

    with modern cephalopods. Intra-rostral porosity was occluded post mortem by earliest diagenetic isopachous calcite cements of a non-biogenic origin. These may have been precipitated due to increased alkalinity related to the decay of organic matter. If this holds true, then the resulting fabric represents a composite biogenic/abiogenic structure precipitated at different times and depths in the water column. We suggest that these findings have significance for those using belemnite rostra as archives of their palaeoenvironment, for the reconstruction of belemnite palaeoecology, and for the functional interpretation of belemnite rostra.

  6. Fabricating fast triggered electro-active shape memory graphite/silver nanowires/epoxy resin composite from polymer template.

    Science.gov (United States)

    Zhou, Jie; Li, Hua; Tian, Ran; Dugnani, Roberto; Lu, Huiyuan; Chen, Yujie; Guo, Yiping; Duan, Huanan; Liu, Hezhou

    2017-07-17

    In recent years shape-memory polymers have been under intense investigation due to their unique mechanical, thermal, and electrical properties that could potentially make them extremely valuable in numerous engineering applications. In this manuscript, we report a polymer-template-assisted assembly manufacturing strategy used to fabricate graphite/silver nanowires/epoxy resin (PGSE) composite. In the proposed method, the porous polymer foams work as the skeleton by forming three-dimensional graphite structure, whereas the silver nanowires act as the continuous conductive network. Preliminary testing on hybrid foams after vacuum infusion showed high electrical conductivity and excellent thermal stability. Furthermore, the composites were found to recover their original shape within 60 seconds from the application of a 0.8 V mm -1 electric field. Notably, the reported shape-memory polymer composites are manufactured with readily-available raw materials, they are fast to manufacture, and are shape-controlled.

  7. Fabricating and strengthening the carbon nanotube/copper composite fibers with high strength and high electrical conductivity

    Science.gov (United States)

    Han, Baoshuai; Guo, Enyu; Xue, Xiang; Zhao, Zhiyong; Li, Tiejun; Xu, Yanjin; Luo, Liangshun; Hou, Hongliang

    2018-05-01

    Combining the excellent properties of carbon nanotube (CNT) and copper, CNT/Cu composite fibers were fabricated by physical vapor deposition (PVD) and rolling treatment. Dense and continuous copper film (∼2 μm) was coated on the surface of the CNT fibers by PVD, and rolling treatment was adopt to strengthen the CNT/Cu composite fibers. After the rolling treatment, the defects between the Cu grains and the CNT bundles were eliminated, and the structure of both the copper film and the core CNT fibers were optimized. The rolled CNT/Cu composite fibers possess high tensile effective strength (1.01 ± 0.13 GPa) and high electrical conductivity ((2.6 ± 0.3) × 107 S/m), and thus, this material may become a promising wire material.

  8. Fabrication of mesoporous silica/polymer composites through solvent evaporation process and investigation of their excellent low thermal expansion property.

    Science.gov (United States)

    Suzuki, Norihiro; Kiba, Shosuke; Yamauchi, Yusuke

    2011-03-21

    We fabricate mesoporous silica/epoxy polymer composites through a solvent evaporation process. The easy penetration of the epoxy polymers into mesopores is achieved by using a diluted polymer solution including a volatile organic solvent. After the complete solvent evaporation, around 90% of the mesopores are estimated to be filled with the epoxy polymer chains. Here we carefully investigate the thermal expansion behavior of the obtained mesoporous silica/polymer composites. Thermal mechanical analysis (TMA) charts revealed that coefficient of linear thermal expansion (CTE) gradually decreases, as the amount of the doped mesoporous silica increases. Compared with spherical silica particle without mesopores, mesoporous silica particles show a greater effect on lowering the CTE values. Interestingly, it is found that the CTE values are proportionally decreased with the decrease of the total amount of the polymers outside the mesopores. These data demonstrate that polymers embedded inside the mesopores become thermally stable, and do not greatly contribute to the thermal expansion behavior of the composites.

  9. DEVELOPMENT OF A FABRICATION PROCESS FOR SOL-GEL/METAL HYDRIDE COMPOSITE GRANULES

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, E; Eric Frickey, E; Leung Heung, L

    2004-02-23

    An external gelation process was developed to produce spherical granules that contain metal hydride particles in a sol-gel matrix. Dimensionally stable granules containing metal hydrides are needed for applications such as hydrogen separation and hydrogen purification that require columns containing metal hydrides. Gases must readily flow through the metal hydride beds in the columns. Metal hydrides reversibly absorb and desorb hydrogen and hydrogen isotopes. This is accompanied by significant volume changes that cause the metal hydride to break apart or decrepitate. Repeated cycling results in very fine metal hydride particles that are difficult to handle and contain. Fine particles tend to settle and pack making it more difficult to flow gases through a metal hydride bed. Furthermore, the metal hydrides can exert a significant force on the containment vessel as they expand. These problems associated with metal hydrides can be eliminated with the granulation process described in this report. Small agglomerates of metal hydride particles and abietic acid (a pore former) were produced and dispersed in a colloidal silica/water suspension to form the feed slurry. Fumed silica was added to increase the viscosity of the feed slurry which helped to keep the agglomerates in suspension. Drops of the feed slurry were injected into a 27-foot tall column of hot ({approx}70 C), medium viscosity ({approx}3000 centistokes) silicone oil. Water was slowly evaporated from the drops as they settled. The drops gelled and eventually solidified to form spherical granules. This process is referred to as external gelation. Testing was completed to optimize the design of the column, the feed system, the feed slurry composition, and the operating parameters of the column. The critical process parameters can be controlled resulting in a reproducible fabrication technique. The residual silicone oil on the surface of the granules was removed by washing in mineral spirits. The granules were

  10. A facile strategy for fabrication of nano-ZnO/yeast composites and their adsorption mechanism towards lead (II) ions

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Wei; Meng, Lingyin [College of Science, Sichuan Agricultural University, Yaan 625014 (China); Mu, Guiqin [Maize Research Institute of Sichuan Agricultural University, Wenjiang 611130 (China); Zhao, Maojun; Zou, Ping [College of Science, Sichuan Agricultural University, Yaan 625014 (China); Zhang, Yunsong, E-mail: yaanyunsong@126.com [College of Science, Sichuan Agricultural University, Yaan 625014 (China)

    2016-08-15

    Highlights: • Nano-ZnO/yeast composites were fabricated by alkali hydrothermal method. • Nano-ZnO was in-situ achieved and anchored on the yeast surface. • Alkali and hydrothermal process cause more exposed funcitional groups on yeast. • Nano-ZnO/yeast composites show higher Pb{sup 2+} adsorption ability than pristine yeast. • Nano-ZnO and exposed functional groups synergistically participate in adsorption. - Abstract: Nano-ZnO/yeast composites were successfully fabricated by one-step alkali hydrothermal method, and their adsorption properties for Pb{sup 2+} ions were also evaluated. Various influencing parameters of nano-ZnO/yeast composites, such as initial pH, contact time and initial Pb{sup 2+} concentration were investigated, respectively. The maximum adsorption capacity of nano-ZnO/yeast composites for Pb{sup 2+} (31.72 mg g{sup −1}) is 2.03 times higher than that of pristine yeast (15.63 mg g{sup −1}). The adsorption mechanism of nano-ZnO/yeast composites was studied by a series of techniques. Scanning electron microscopy (SEM) showed that nano-ZnO is evenly deposited on yeast surface. Atomic force microscopy (AFM) analysis exhibited that the yeast surface is rougher than that of pristine yeast. Energy dispersive X-ray detector (EDX) and X-ray diffraction (XRD) indicated the existence of nano-ZnO on yeast surface. Additionally, X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) measurements further illustrated that alkali hydrothermal method causes not only the generation and anchorage of nano-ZnO on yeast surface but also the exposure of more functional groups (such as amino, carboxyl groups etc.) on yeast surface, both of which could adsorb Pb{sup 2+} via synergistic effect.

  11. Study on the friction and wear properties of glass fabric composites filled with nano- and micro-particles under different conditions

    International Nuclear Information System (INIS)

    Su Fenghua; Zhang Zhaozhu; Liu Weimin

    2005-01-01

    The glass fabric composites filled with the particulates of polytetrafluoroethylene (PTFE), micro-sized MoS 2 , nano-TiO 2 , and nano-CaCO 3 , respectively, were prepared by dip-coating of the glass fabric in a phenolic resin containing the particulates to be incorporated and the successive curing. The friction and wear behaviors of the resulting glass fabric composites sliding against AISI-1045 steel in a pin-on-disk configuration at various temperatures were evaluated on a Xuanwu-III high temperature friction and wear tester. The morphologies of the worn surfaces of the filled glass fabric composites and the counterpart steel pins were analyzed by means of scanning electron microscopy, and the elemental distribution of F on the worn surface of the counterpart steel was determined by means of energy dispersive X-ray analysis (EDXA). It was found that PTFE and nano-TiO 2 particulates as the fillers contributed to significantly improve the friction-reducing and anti-wear properties of the glass fabric composites, but nano-CaCO 3 and micro-MoS 2 as the fillers were harmful to the friction and wear behavior of the glass fabric composites. The friction and wear properties of the glass fabric composites filled with the particulate fillers were closely dependent on the environmental temperature and the wear rates of the composites at elevated temperature above 200 deg. C were much larger than that below 150 deg. C, which was attributed to the degradation and decomposition of the adhesive resin at excessively elevated temperature. The bonding strengths between the interfaces of the glass fabric, the adhesive resin, and the incorporated particulates varied with the types of the particulate fillers, which largely accounted for the differences in the tribological properties of the glass fabric composites filled with different fillers. Moreover, the transferred layers of varied features formed on the counterpart steel pins also partly accounted for the different friction and

  12. "light-on" sensing of antioxidants using gold nanoclusters

    KAUST Repository

    Hu, Lianzhe

    2014-05-20

    Depletion of intracellular antioxidants is linked to major cytotoxic events and cellular disorders, such as oxidative stress and multiple sclerosis. In addition to medical diagnosis, determining the concentration of antioxidants in foodstuffs, food preservatives, and cosmetics has proved to be very vital. Gold nanoclusters (Au-NCs) have a core size below 2 nm and contain several metal atoms. They have interesting photophysical properties, are readily functionalized, and are safe to use in various biomedical applications. Herein, a simple and quantitative spectroscopic method based on Au-NCs is developed to detect and image antioxidants such as ascorbic acid. The sensing mechanism is based on the fact that antioxidants can protect the fluorescence of Au-NCs against quenching by highly reactive oxygen species. Our method shows great accuracy when employed to detect the total antioxidant capacity in commercial fruit juice. Moreover, confocal fluorescence microscopy images of HeLa cells show that this approach can be successfully used to image antioxidant levels in living cells. Finally, the potential application of this "light-on" detection method in multiple logic gate fabrication was discussed using the fluorescence intensity of Au-NCs as output. © 2014 American Chemical Society.

  13. Tailoring the morphology of raspberry-like carbon black/polystyrene composite microspheres for fabricating superhydrophobic surface

    International Nuclear Information System (INIS)

    Bao, Yubin; Li, Qiuying; Xue, Pengfei; Huang, Jianfeng; Wang, Jibin; Guo, Weihong; Wu, Chifei

    2011-01-01

    In our previous report, raspberry-like carbon black/polystyrene (CB/PS) composite microsphere was prepared through heterocoagulation process. Based on the previous study, in the present work, the morphology of raspberry-like CB/PS particle is tailored through adjusting the polarity and the concentration ratio of CB/PS colloidal suspension with the purpose to prepare particulate film for the fabrication of superhydrophobic surface. Scanning electron microscope (SEM) confirms the morphology of raspberry-like particle and the coverage of CB. Rough surfaces fabricated by raspberry-like particles with proper morphology are observed by SEM and clear evidence of superhydrophobic surface is shown. The structure of raspberry-like particle is analyzed by atom force microscope. The proposed relationship between the hydrophobicity and the structure of CB aggregates on the surface of PS microsphere is discussed in details.

  14. Fabrication of Al5083/B4C surface composite by friction stir processing and its tribological characterization

    Directory of Open Access Journals (Sweden)

    Narayana Yuvaraj

    2015-10-01

    Full Text Available Improved surface properties with the retainment of bulk properties are necessary for a component for enhanced wear characteristics. Friction stir processing (FSP is used to produce such surface composites. Fabrication of 5083 aluminum alloy with reinforced layers of boron carbide (B4C through FSP was carried out. Micro and nano sized B4C particles were used as reinforcements. The friction processed surface composite layer was analyzed through optical and scanning electron microscopical studies. The number of passes and the size of reinforcement play a vital role in the development of surface composites by FSP. Mechanical properties of the friction stir processed surface composites were evaluated through micro hardness and universal tensile tests. The results were compared with the properties of the base metal. The role of reinforcement and number of passes on properties were also evaluated. Tribological performance of the surface composites is tested through pin on disk test. The surface composite layer resulted in three passes with nano particle reinforcement exhibited better properties in hardness, tensile behavior and wear resistance compared to the behavior of the base metal.

  15. Microstructure and characteristics of the metal-ceramic composite (MgCa-HA/TCP) fabricated by liquid metal infiltration.

    Science.gov (United States)

    Gu, X N; Wang, X; Li, N; Li, L; Zheng, Y F; Miao, Xigeng

    2011-10-01

    In this article, a novel MgCa alloy-hydroxyapatite-tricalcium phosphate (HA/TCP) composite was fabricated using the liquid alloy infiltration technique. The feasibility of the composite for biomedical applications was studied through mechanical testing, electrochemical testing, immersion testing, and cell culture evaluation. It was shown that the composite had a strength about 200-fold higher than that of the original porous HA/TCP scaffold but retained half of the strength of the bulk MgCa alloy. The corrosion test indicated that the resulting composite exhibited an average corrosion rate of 0.029 mL cm⁻² h⁻¹ in the Hank's solution at 37°C, which was slower than that of the bulk MgCa alloy alone. The indirect cytotoxicity evaluation revealed that 100% concentrated (i.e., undiluted or as-collected) extract of the MgCa-HA/TCP composite showed significant toxicity to L-929 and MG63 cells (p composite exhibited a similar degree of cell viability (p > 0.05), equivalent to the grade I cytotoxicity of the standard ISO 10993-5: 1999. Copyright © 2011 Wiley Periodicals, Inc.

  16. Resonant surface-enhanced Raman scattering by optical phonons in a monolayer of CdSe nanocrystals on Au nanocluster arrays

    Energy Technology Data Exchange (ETDEWEB)

    Milekhin, Alexander G., E-mail: milekhin@isp.nsc.ru [A.V. Rzhanov Institute of Semiconductor Physics, pr. Lavrentjeva, 13, 630090 Novosibirsk (Russian Federation); Novosibirsk State University, Pirogov str. 2, 630090 Novosibirsk (Russian Federation); Sveshnikova, Larisa L.; Duda, Tatyana A. [A.V. Rzhanov Institute of Semiconductor Physics, pr. Lavrentjeva, 13, 630090 Novosibirsk (Russian Federation); Rodyakina, Ekaterina E. [A.V. Rzhanov Institute of Semiconductor Physics, pr. Lavrentjeva, 13, 630090 Novosibirsk (Russian Federation); Novosibirsk State University, Pirogov str. 2, 630090 Novosibirsk (Russian Federation); Dzhagan, Volodymyr M. [Semiconductor Physics, Technische Universität Chemnitz, D-09107 Chemnitz (Germany); Sheremet, Evgeniya [Solid Surfaces Analysis, Technische Universität Chemnitz, D-09107 Chemnitz (Germany); Gordan, Ovidiu D. [Semiconductor Physics, Technische Universität Chemnitz, D-09107 Chemnitz (Germany); Himcinschi, Cameliu [Institut für Theoretische Physik, TU Bergakademie Freiberg, 09596 Freiberg (Germany); Latyshev, Alexander V. [A.V. Rzhanov Institute of Semiconductor Physics, pr. Lavrentjeva, 13, 630090 Novosibirsk (Russian Federation); Novosibirsk State University, Pirogov str. 2, 630090 Novosibirsk (Russian Federation); Zahn, Dietrich R.T. [Semiconductor Physics, Technische Universität Chemnitz, D-09107 Chemnitz (Germany)

    2016-05-01

    Highlights: • Regular Au nanocluster and dimer arrays as well as single Au dimers are fabricated. • Resonant SERS by monolayers of CdSe nanocrystals deposited on the Au nanostructures is observed. • LO energy change for CdSe NCs on different single Au dimers indicates SERS by single or a few NCs. - Abstract: Here we present the results on an investigation of resonant Stokes and anti- Stokes surface-enhanced Raman scattering (SERS) by optical phonons in colloidal CdSe nanocrystals (NCs) homogeneously deposited on arrays of Au nanoclusters using the Langmuir–Blodgett technology. The thickness of deposited NCs, determined by transmission and scanning electron microscopy, amounts to approximately 1 monolayer. Special attention is paid to the determination of the localized surface plasmon resonance (LSPR) energy in the arrays of Au nanoclusters as a function of the nanocluster size by means of micro-ellipsometry. SERS by optical phonons in CdSe NCs shows a significant enhancement factor with a maximal value of 2 × 10{sup 3} which depends resonantly on the Au nanocluster size and thus on the LSPR energy. The deposition of CdSe NCs on the arrays of Au nanocluster dimers enabled us to study the polarization dependence of SERS. It was found that a maximal SERS signal is observed for the light polarization along the dimer axis. Finally, SERS by optical phonons was observed for CdSe NCs deposited on the structures with a single Au dimer. A difference of the LO phonon energy is observed for CdSe NCs on different single dimers. This effect is explained as the confinement-induced shift which depends on the CdSe nanocrystal size and indicates quasi-single NC Raman spectra being obtained.

  17. Nanoclusters and Microparticles in Gases and Vapors

    CERN Document Server

    Smirnov, Boris M

    2012-01-01

    Research of processes involving Nanoclusters and Microparticleshas been developing fastin many fields of rescent research, in particular in materials science. To stay at the cutting edge of this development, a sound understanding of the processes is needed. In this work, several processes involving small particles are described, such as transport processes in gases, charging of small particles in gases, chemical processes, atom attachment and quenching of excited atomic particles on surfaces, nucleation, coagulation, coalescence and growth processes for particles and aggregates. This work pres

  18. Fabrication, testing and analysis of steel/composite DLS adhesive joints

    DEFF Research Database (Denmark)

    Nashim, S.; Nisar, J.; Tsouvalis, N.

    2009-01-01

    This paper aims to provide a guide on the design and fabrication of thick adherend double lap shear joints (DLS), often referred to as butt connections/joints in ship structures including patch repair. The specimens consist of 10mm steel inner adherend and various outer adherend materials including...... fabrication method, (ii) to determine joint strength and overlap plateau for various specimens with a range of material combinations and (iii) to understand aspects of failure and design of joint under quasi-static loading. The paper presents experimental and numerical details with key conclusions....

  19. Exotic high activity surface patterns in PtAu nanoclusters

    KAUST Repository

    Mokkath, Junais Habeeb

    2013-05-09

    The structure and chemical ordering of PtAu nanoclusters of 79, 135, and 201 atoms are studied via a combination of a basin hopping atom-exchange technique (to locate the lowest energy homotops at fixed composition), a symmetry orbit technique (to find the high symmetry isomers), and density functional theory local reoptimization (for determining the most stable homotop). The interatomic interactions between Pt and Au are derived from the empirical Gupta potential. The lowest energy structures show a marked tendency toward PtcoreAushell chemical ordering by enrichment of the more cohesive Pt in the core region and of Au in the shell region. We observe a preferential segregation of Pt atoms to (111) facets and Au atoms to (100) facets of the truncated octahedron cluster motif. Exotic surface patterns are obtained particularly for Pt-rich compositions, where Pt atoms are being surrounded by Au atoms. These surface arrangements boost the catalytic activity by creating a large number of active sites. © 2013 American Chemical Society.

  20. Direct composite resin layering techniques for creating lifelike CAD/CAM-fabricated composite resin veneers and crowns.

    Science.gov (United States)

    LeSage, Brian

    2014-07-01

    Direct composite resin layering techniques preserve sound tooth structure and improve function and esthetics. However, intraoral placement techniques present challenges involving isolation, contamination, individual patient characteristics, and the predictability of restorative outcomes. Computer-aided design and computer-aided manufacturing (CAD/CAM) restorations enable dentists to better handle these variables and provide durable restorations in an efficient and timely manner; however, milled restorations may appear monochromatic and lack proper esthetic characteristics. For these reasons, an uncomplicated composite resin layering restoration technique can be used to combine the benefits of minimally invasive direct restorations and the ease and precision of indirect CAD/CAM restorations. Because most dentists are familiar with and skilled at composite resin layering, the use of such a technique can provide predictable and highly esthetic results. This article describes the layered composite resin restoration technique. Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  1. Optimal Composite Materials using NASA Resins or POSS Nanoparticle Modifications for Low Cost Fabrication of Large Composite Aerospace Structures Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Reduced mass composite materials are crucial to the success of aerospace systems, but their adoption is inhibited because they require autoclave consolidation, a...

  2. Comfort and Functional Properties of Far-Infrared/Anion-Releasing Warp-Knitted Elastic Composite Fabrics Using Bamboo Charcoal, Copper, and Phase Change Materials

    Directory of Open Access Journals (Sweden)

    Ting-Ting Li

    2016-02-01

    Full Text Available Elastic warp-knitted composite fabrics with far-infrared emissivity and an anion-releasing property were prepared using bamboo charcoal (BC, copper (Cu, and phase-change material (PCM. The functional composite fabric, which was composed of self-made complex yarns with various twisting degrees and material composition, were created using a rotor twister and ring-spinning technique. The fabric structure was diversified by the feeding modes of weft yarn into a crochet-knitting machine. The twist number of complex yarns was optimized by tensile tenacity, twist contraction, and hairiness, and analysis showed that twisting at 12 twists per inch produced the highest tensile tenacity and appropriate twist contraction and hairiness. Comfort evaluation showed that the elastic composite fabrics with BC weft yarns exhibited higher water–vapor transmission rate and air permeability, reaching 876 g/m2∙ day and 73.2 cm3/s/cm2, respectively. Three structures of composite fabric with various weft yarns had >0.85 ε far-infrared emissivity and 350–420 counts/cm3 anion amount. The prepared elastic warp-knitted fabrics can provide a comfortable, dry, and breathable environment to the wearer and can thus be applied as health-care textiles in the future.

  3. Modelling the thermo-elastic properties of skewed woven fabric reinforced composites

    NARCIS (Netherlands)

    Lamers, E.A.D.; Wijskamp, Sebastiaan; Akkerman, Remko

    2000-01-01

    Woven fabrics prove to be a very convenient fibre reinforcement when prepreg layers have to be draped on to double curvature moulds. The process of draping causes the angle between the warp and weft yarns to vary over the product with this double curvature. As a result, the thermomechanical

  4. Fabrication and characterization of poly(vinyl alcohol/carbon nanotube melt-spinning composites fiber

    Directory of Open Access Journals (Sweden)

    Zhiqian Yang

    2015-10-01

    Full Text Available A composite fiber based on carbon nanotube (CNT and poly(vinyl alcohol (PVA was prepared by melt-spinning. Structural features and the mechanical performances of the PVA/CNT composite fiber were investigated as a function of draw condition. Initial moduli and tensile strengths of the drawn composite fibers are much higher than those of undrawn composite fiber. It is identified from XRD and 2D XRD that the composite fiber exhibits enhanced crystallinity and orientation degree with increasing the draw ratio. Accordingly, finger-like pores distributed along the axial direction homogeneous on the melt-spinning PVA fiber surface. After dry and hot-drawn, the hydrophobicity of PVA/CNT composites fiber decreased gradually.

  5. Fabrication of homogeneously dispersed graphene/Al composites by solution mixing and powder metallurgy

    Science.gov (United States)

    Zeng, Xiang; Teng, Jie; Yu, Jin-gang; Tan, Ao-shuang; Fu, Ding-fa; Zhang, Hui

    2018-01-01

    Graphene-reinforced aluminum (Al) matrix composites were successfully prepared via solution mixing and powder metallurgy in this study. The mechanical properties of the composites were studied using microhardness and tensile tests. Compared to the pure Al alloy, the graphene/Al composites showed increased strength and hardness. A tensile strength of 255 MPa was achieved for the graphene/Al composite with only 0.3wt% graphene, which has a 25% increase over the tensile strength of the pure Al matrix. Raman spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, and transmission electron microscopy were used to investigate the morphologies, chemical compositions, and microstructures of the graphene and the graphene/Al composites. On the basis of fractographic evidence, a relevant fracture mechanism is proposed.

  6. Microstructure and Properties of 5083 Al/1060 Al/AZ31 Composite Plate Fabricated by Explosive Welding

    Science.gov (United States)

    Yang, Suyuan; Bao, Jiawei

    2018-03-01

    A 5083 Al/1060 Al/AZ31 composite plate was fabricated by explosive welding. The microstructure and properties of the composite plate were investigated after explosive welding. The results showed that all bonding interfaces were wavy interfaces. With an increasing distance from the detonation point, the wavelength and the amplitude also increased. The EDS results indicated that a 5-μm diffusion layer was observed at the 1060 Al/AZ31 layer, including the Mg2Al3 phase. Adiabatic shear bands and twin structures were observed in AZ31. The shear bond strength of the 5083 Al/1060 Al interface was 60 MPa, and the shear bond strength of the 1060 Al/AZ31 interface was 84 MPa.

  7. Flourescent Peptide-Stabilized Silver-Nanoclusters

    DEFF Research Database (Denmark)

    Gregersen, Simon

    Fluorescent probes are widely used in the fields of imaging, detection, and diagnostics, and in order to achieve methodical progress, the search for new tools is an on-going quest. Within the last few decades, few-atom noble metal nanoclusters (NCs) have gathered increasing attention due to their......Fluorescent probes are widely used in the fields of imaging, detection, and diagnostics, and in order to achieve methodical progress, the search for new tools is an on-going quest. Within the last few decades, few-atom noble metal nanoclusters (NCs) have gathered increasing attention due...... to their physical and optoelectronic properties. These include great photostability, low toxicity, small size, and tunable spectral properties. Chemical stability of noble metal NCs is, however, very low, and they only exist transiently without a stabilizing scaffold. This has to date been done in solution using....../reorganization of the peptide to facilitate NC formation. Following an initial chelation involving the thiol-functionality of cysteine side-chains, the coordination of silver into a defined NC is expected to be the driving force of the folding process. This work also illustrates the shortcomings of MALDI-TOF mass spectrometry...

  8. Fabrication and characterization of a micromachined swirl-shaped ionic polymer metal composite actuator with electrodes exhibiting asymmetric resistance.

    Science.gov (United States)

    Feng, Guo-Hua; Liu, Kim-Min

    2014-05-12

    This paper presents a swirl-shaped microfeatured ionic polymer-metal composite (IPMC) actuator. A novel micromachining process was developed to fabricate an array of IPMC actuators on a glass substrate and to ensure that no shortcircuits occur between the electrodes of the actuator. We demonstrated a microfluidic scheme in which surface tension was used to construct swirl-shaped planar IPMC devices of microfeature size and investigated the flow velocity of Nafion solutions, which formed the backbone polymer of the actuator, within the microchannel. The unique fabrication process yielded top and bottom electrodes that exhibited asymmetric surface resistance. A tool for measuring surface resistance was developed and used to characterize the resistances of the electrodes for the fabricated IPMC device. The actuator, which featured asymmetric electrode resistance, caused a nonzero-bias current when the device was driven using a zero-bias square wave, and we propose a circuit model to describe this phenomenon. Moreover, we discovered and characterized a bending and rotating motion when the IPMC actuator was driven using a square wave. We observed a strain rate of 14.6% and a displacement of 700 μm in the direction perpendicular to the electrode surfaces during 4.5-V actuation.

  9. Fabrication of calcite blocks from gypsum blocks by compositional transformation based on dissolution-precipitation reactions in sodium carbonate solution.

    Science.gov (United States)

    Ishikawa, Kunio; Kawachi, Giichiro; Tsuru, Kanji; Yoshimoto, Ayami

    2017-03-01

    Calcium carbonate (CaCO 3 ) has been used as a bone substitute, and is a precursor for carbonate apatite, which is also a promising bone substitute. However, limited studies have been reported on the fabrication of artificial calcite blocks. In the present study, cylindrical calcite blocks (ϕ6×3mm) were fabricated by compositional transformation based on dissolution-precipitation reactions using different calcium sulfate blocks as a precursor. In the dissolution-precipitation reactions, both CaSO 4 ·2H 2 O and CaSO 4 transformed into calcite, a polymorph of CaCO 3 , while maintaining their macroscopic structure when immersed in 1mol/L Na 2 CO 3 solution at 80°C for 1week. The diametral tensile strengths of the calcite blocks formed using CaSO 4 ·2H 2 O and CaSO 4 were 1.0±0.3 and 2.3±0.7MPa, respectively. The fabrication of calcite blocks using CaSO 4 ·2H 2 O and CaSO 4 proposed in this investigation may be a useful method to produce calcite blocks because of the self-setting ability and high temperature stability of gypsum precursors. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Characterization of fabricated cobalt-based alloy/nano bioactive glass composites

    International Nuclear Information System (INIS)

    Bafandeh, Mohammad Reza; Gharahkhani, Raziyeh; Fathi, Mohammad Hossein

    2016-01-01

    In this work, cobalt-based alloy/nano bioactive glass (NBG) composites with 10, 15 and 20 wt% NBG were prepared and their bioactivity after immersion in simulated body fluid (SBF) for 1 to 4 weeks was studied. Scanning electron microscopy images of two- step sintered composites revealed relatively dense microstructure. The results showed that density of composite samples decreased with increase in NBG amount. The microstructure analysis as well as energy dispersive X-ray analysis (EDX) revealed that small amount of calcium phosphate phases precipitates on the surface of composite samples after 1 week immersion in SBF. After 2 weeks immersion, considerable amounts of cauliflower-like shaped precipitations were seen on the surface of the composites. Based on EDX analysis, these precipitations were composed mainly from Ca, P and Si. The observed bands in the Fourier transform infrared spectroscopy of immersed composites samples for 4 weeks in SBF, were characteristic bands of hydroxyapatite. Therefore it is possible to form hydroxyapatite layer on the surface of composite samples during immersion in SBF. The results indicated that prepared composites unlike cobalt-based alloy are bioactive, promising their possibility for implant applications. - Highlights: • Co-based alloy/nano bioactive glass (NBG) composites with 10, 15 and 20 wt% NBG were prepared. • In order to study their bioactivity, composite samples were immersed in SBF solution for 1 to 4 weeks. • Immersion in SBF accompanied with precipitation of hydroxyapatite on surface of samples. • Prepared composite samples unlike cobalt-based alloy were bioactive.

  11. Fabrication, thermal and electrical properties of polyphenylene sulphide/copper composites

    International Nuclear Information System (INIS)

    Goyal, R.K.; Kambale, K.R.; Nene, S.S.; Selukar, B.S.; Arbuj, S.; Mulik, U.P.

    2011-01-01

    Highlights: → Polyphenylene sulphide/copper composites show a low percolation threshold, i.e., about 6 vol% Cu. → Both pre- and post- glass transition coefficient of thermal expansion (CTE) of composites decreased significantly. → The microhardness was increased by more than 50% compared to pure PPS matrix. → The electrical conductivity was increased by about eight orders of magnitude for 18 vol% Cu composite. → Dielectric constant and dissipation factor of composites measured at MHz was increased to about 6-fold and 70-fold compared to PPS matrix. - Abstract: The thermal and electrical properties of high performance poly(phenylene sulphide) (PPS) composites reinforced up to 31 vol% Cu particles were investigated to be used as materials for electronic applications. The thermal stability and char yield of the composites increased significantly. Both pre- and post- glass transition coefficient of thermal expansion (CTE) of composites decreased significantly. The microhardness was increased by more than 50% compared to pure PPS matrix. Microhardness and CTE of composites correlated well with the rule of mixtures. A percolation threshold about 6 vol% Cu was obtained. The electrical conductivity was increased by about eight orders of magnitude for 18 vol% composite. Dielectric constant and dissipation factor of composites at 1 MHz was increased by about 6-fold and 70-fold compared to matrix, respectively. They decreased gradually with increasing frequency up to 1 MHz and thereafter, there was insignificant change. The scanning electron microscope showed almost uniform distribution of Cu particles in the matrix. Owing to better dimensional stability and good electrical properties, these composites are very promising for electronic applications.

  12. Fabrication of Mn3O4-carbon nanotube composites with high areal capacitance using cationic and anionic dispersants.

    Science.gov (United States)

    Ata, M S; Milne, J; Zhitomirsky, I

    2018-02-15

    Mn 3 O 4 -multiwalled carbon nanotube (MWCNT) electrodes for supercapacitors with high active mass loadings have been fabricated with the goal of achieving a high area normalized capacitance (C S ) and enhanced capacitance retention at high charge-discharge rates. Poly(4-styrenesulfonic acid-co-maleic acid) sodium salt P(SSA-MA) was used as a charging and dispersing agent for the fabrication of Mn 3 O 4 . The unique bonding properties of the MA monomers allowed efficient P(SSA-MA) adsorption on Mn 3 O 4 , whereas SSA monomers imparted a negative charge. Cationic ethyl violet (EV) and pyronin Y (PY) dyes were used for dispersion and charging of MWCNT. Good dispersion of the individual components and their electrostatic heterocoagulation facilitated efficient mixing, which allowed enhanced capacitive behavior at mass loadings of 28.4 mg cm -2 , which meet requirements for practical applications. The highest capacitance of 2.8 F cm -2 was obtained at a scan rate of 2 mV s -1 for the composites, prepared using PY. However, the composites, prepared using EV showed better capacitance retention of 88% in the scan rate range of 2-100 mV s -1 and the capacitance of 2.1 F cm -2 was obtained at a scan rate of 100 mV s -1 . The composites showed activation behavior during cycling, which resulted in a capacitance increase and electrical resistance reduction. The results of this investigation showed that Mn 3 O 4 -MWCNT composites, prepared by new colloidal methods are promising materials for practical applications in electrochemical supercapacitors. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Fabrication and characterization of microstructure of stainless steel matrix composites containing up to 25 vol% NbC

    International Nuclear Information System (INIS)

    Kan, Wen Hao; Ye, Zi Jie; Zhu, Yue; Bhatia, Vijay Kumar; Dolman, Kevin; Lucey, Timothy; Tang, Xinhu; Proust, Gwénaëlle; Cairney, Julie

    2016-01-01

    AISI 440 stainless steels reinforced with various volume fractions of niobium carbide (NbC) particles of up to 25 vol% were fabricated in-situ using an argon arc furnace and then heat-treated to produce a martensitic matrix. Optical and scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and electron back-scatter diffraction (EBSD) techniques were used to analyze the microstructure, phases and composition of these composites. Interestingly, it was found that Chinese-script NbC could nucleate on existing primary NbC particles creating NbC clusters with complex microstructures. Additionally, hardness tests were used to evaluate viability in mining and mineral processing applications. The increase in NbC content resulted in an overall increase in the hardness of the composites while causing a marginal decrease in the amount of Cr in solid solution with the matrix, which could be a concern for corrosion resistance. The latter was due to the fact that the NbC lattice could dissolve a minor amount of Cr. Thermodynamic simulations also attributed this to a slight increase in M 7 C 3 precipitation. Nonetheless, these novel composites show great promise for applications in wear and corrosive environments. - Highlights: •Stainless steels reinforced with NbC particles of up to 25 vol% were fabricated. •NbC was formed in-situ in the steels using an arc melter. •Martensitic transformation of the matrix of each sample was achieved. •NbC reinforcements increased the bulk hardness values of the steels. •Dissolved Cr in the matrix of each sample was sufficient for passivity in theory.

  14. Wood-based Tri-Axial Sandwich Composite Materials: Design, Fabrication, Testing, Modeling and Application

    Science.gov (United States)

    Jinghao Li; John F. Hunt; Shaoqin Gong; Zhiyong Cai

    2014-01-01

    As the demand for sustainable materials increases, there are unique challenges and opportunities to develop light-weight green composites materials for a wide range of applications. Thus wood-based composite materials from renewable forests may provide options for some niche applications while helping to protect our environment. In this paper, the wood-based tri-axial...

  15. Fabrication and performances of MWCNT/TiO2 composites derived ...

    Indian Academy of Sciences (India)

    Administrator

    composites showed microbicidal effects and strong anti- bacterial activity against E. coli. Solar disinfection with. MWCNT/TiO2 composite is a consequence of both the direct action of the light on the microorganisms and the photocatalytic action of the photo-induced electron (e. –. ) accepted by the MWCNT from the sunlight.

  16. Influence of nanoparticles additivies on mechanical properties of fabric reinforced composites

    Czech Academy of Sciences Publication Activity Database

    Suchý, T.; Balík, Karel; Sucharda, Zbyněk; Černý, Martin; Sochor, M.

    2007-01-01

    Roč. 10, 69-72 (2007), s. 1-2 ISSN 1429-7248. [Conference Biomaterials in Medicine and Veterinary Medicine /17./. Rytro, 11.10.2007-14.10.2007] R&D Projects: GA ČR GA106/03/1167 Institutional research plan: CEZ:AV0Z30460519 Keywords : composites * hydroxyapatite * mechanicle properties Subject RIV: JI - Composite Materials

  17. Fabrication and performances of MWCNT/TiO2 composites derived ...

    Indian Academy of Sciences (India)

    Multi-walled carbon nanotubes (MWCNTs)/TiO2 composites were synthesized by sol–gel technique using titanium (IV) -butoxide (TNB), titanium (IV) isopropoxide (TIP) and titanium (IV) propoxide (TPP) as different titanium alkoxide precursors. The as-prepared composites were comprehensively characterized by BET ...

  18. X-ray structure analysis and elastic properties of a fabric reinforced carbon-carbon composite

    Czech Academy of Sciences Publication Activity Database

    Dobiášová, L.; Starý, V.; Glogar, Petr; Valvoda, V.

    2002-01-01

    Roč. 40, č. 9 (2002), s. 1419-1426 ISSN 0008-6223 R&D Projects: GA ČR GA106/99/0626 Institutional research plan: CEZ:AV0Z3046908 Keywords : carbon-carbon composite Subject RIV: JI - Composite Materials Impact factor: 3.048, year: 2002

  19. Crystallization of silicon nanoclusters with inert gas temperature control

    Science.gov (United States)

    Zhao, Junlei; Singh, Vidyadhar; Grammatikopoulos, Panagiotis; Cassidy, Cathal; Aranishi, Kengo; Sowwan, Mukhles; Nordlund, Kai; Djurabekova, Flyura

    2015-01-01

    We analyze the fundamental process of crystallization of silicon nanoclusters by means of molecular dynamics simulations, complemented by magnetron-sputter inert gas condensation, which was used to synthesize polycrystalline silicon nanoclusters with good size control. We utilize two well-established Si interatomic potentials: the Stillinger-Weber and the Tersoff III. Both the simulations and experiments show that upon cooling down by an Ar gas thermal bath, initially liquid, free-standing Si nanocluster can grow multiple crystal nuclei, which drive their transition into polycrystalline solid nanoclusters. The simulations allow detailed analysis of the mechanism, and show that the crystallization temperature is size-dependent and that the probability of crystalline phase nucleation depends on the highest temperature the cluster reaches during the initial condensation and the cooling rate after it.

  20. Toward an Understanding of Catalysis by Supported Metal Nanoclusters

    Energy Technology Data Exchange (ETDEWEB)

    D. W. Goodman; J. Wang; B. K. Min; E. Ozensoy; F. Yang

    2002-01-01

    OAK (B204) The goal of this program is an atomic-level understanding of catalysis by supported metal nanoclusters, especially the surface intermediates in selective oxidation by noble metal nanocatalysts.

  1. Adsorption of small gas molecules on B36 nanocluster

    Indian Academy of Sciences (India)

    Supplementary Information. Journal of Chemical Sciences. Adsorption of small gas molecules on B36 nanocluster. YOUNES VALADBEIGI. *. , HOSSEIN FARROKHPOUR and MAHMOUD TABRIZCHI. Department of chemistry, Isfahan University of Technology, Isfahan, 84156-83111, Iran. *. Corresponding Author: Younes ...

  2. Fabrication and characterization of LATP/PAN composite fiber-based lithium-ion battery separators

    International Nuclear Information System (INIS)

    Liang Yinzheng; Lin Zhan; Qiu Yiping; Zhang Xiangwu

    2011-01-01

    Lithium aluminum titanium phosphate (LATP)/polyacrylonitrile (PAN) composite fiber-based membranes were prepared by electrospinning dispersions of LATP particles in PAN solutions. The electrolyte uptakes of the electrospun LATP/PAN composite fiber-based membranes were measured and the results showed that the electrolyte uptake increased as the LATP content increased. The lithium ion conductivity, the electrochemical oxidation limit and the interface resistance of liquid electrolyte-soaked electrospun LATP/PAN composite fiber-based membranes were also measured and it was found that as the LATP content increased, the electrospun LATP/PAN composite fiber-based membranes had higher lithium ion conductivity, better electrochemical stability, and lower interfacial resistance with lithium electrode. Additionally, lithium//1 M LiPF 6 /EC/EMC//lithium iron phosphate cells using LATP/PAN composite fiber-based membranes as the separator demonstrated high charge/discharge capacity and good cycle performance.

  3. Characteristics of W-20Cu nano-crystallite composites fabricated by mechanical alloying.

    Science.gov (United States)

    Wang, Fengtao; Wu, Yucheng; Wang, Tugen; Ren, Rong

    2010-08-01

    In the present study, the microstructure and properties characteristics of W-20Cu nano-crystallite composites were investigated. Characterization techniques like XRD and SEM have been used to study the crystallite size of W-Cu powder obtained by mechanical alloying. As well as, the effect of milling time on the microstructure and properties of W-20Cu composites was discussed. The results show that with increasing milling time, the crystallite size of W-Cu composite powder decreased and kept steady at last, and the crystallite size of W(Cu) solid solution was 6.6 nm for milling 20 h. The microstructure of W-20Cu composites became homogeneous and tungsten crystallite size became fine. The relative density and bending strength of W-20Cu composites increased. The value of thermal conductivity peaked when milling time was 20 h.

  4. Fabrication and dielectric characterization of barium hexaferrite/UHMWPE composite for energy storage applications

    Science.gov (United States)

    Aljarrah, Mohannad T.; Al-Saleh, Mohammed H.; Al-Harahsheh, Mohammad

    2017-10-01

    Barium hexaferrite (BaM)/ultrahigh molecular weight polyethylene (UHMWPE) composite with remarkably high electrical charge storage capabilities has been developed. The BaM particles were synthesized by the chemical co-precipitation approach followed by sintering at high temperatures. The composites were prepared by dry compounding followed by molding at high temperature and pressure. The BaM nanoparticles were localized at the surface of the UHMWPE microparticles and consequently formed a mesh-like network of honeycomb structure within the composite matrix. The impedance analysis showed that the composite filled with only 2 wt% BaM exhibits a dielectric (ε ‧) constant and dissipation factor (tan δ) of 116 and 0.01, respectively, revealing that this composite is attractive for electric charge storage applications.

  5. Isotropy equilibrium of the double woven fabric with cotton face and wool reverse fibrous compositions

    Science.gov (United States)

    Rahnev, I.; Rimini, G.

    2017-10-01

    The equilibrium of the masses and the mechanical properties between the warp and the weft is a determining factor for the quality of the woven fabrics. When the fabric has a multi-layered structure and is designed for protective clothing, the uniform distribution of the elastical resistance acquires a paramount importance for the consumer properties. Isotropy in the sense of absolute equalising of the properties between the base and the weft evaluates the achieved optimum cohesion between the weaving threads and directs the weaving cycle settings. The possible variation of the ratio between the elastic modules of the warp and the weft, depending on the weft spacing and the warp tension, is the basic idea of this article.

  6. Influence of graphite filler on two-body abrasive wear behaviour of carbon fabric reinforced epoxy composites

    International Nuclear Information System (INIS)

    Suresha, B.; Ramesh, B.N.; Subbaya, K.M.; Ravi Kumar, B.N.; Chandramohan, G.

    2010-01-01

    The influence of graphite filler additions on two-body abrasive wear behaviour of compression moulded carbon-epoxy (C-E) composites have been evaluated using reciprocating wear unit and pin-on-disc wear unit under single pass and multi-pass conditions respectively. The carbon fabric used in the present study is a plain one; each warp fiber pass alternately under and over each weft fiber. The fabric is symmetrical, with good stability and reasonable porosity. Abrasive wear studies were carried out under different loads/abrading distance using different grades of SiC abrasive paper (150 and 320 grit size). Graphite filler in C-E reduced the specific wear rate. Further, the wear volume loss drops significantly with increase in graphite content. Comparative wear performance of all the composites showed higher specific wear rate in two-body wear (single-pass conditions) compared to multi-pass conditions. Further, the tribo-performance of C-E indicated that the graphite filler inclusion resulted in enhancement of wear behaviour significantly. Wear mechanisms were suggested and strongly supported by worn surface morphology using scanning electron microscopy.

  7. Digital selective fabrication of micro/nano-composite structured TiO2 nanorod arrays by laser direct writing

    Science.gov (United States)

    Jiang, Wei; He, Xiaoning; Liu, Hongzhong; Yin, Lei; Shi, Yongsheng; Ding, Yucheng

    2014-11-01

    In this article, we report on the digital selective fabrication of micro/nano-composite structured TiO2 nanorod arrays by laser direct writing. The pattern of TiO2 nanorod arrays can be easily designed and fabricated by laser scanning technology integrated with a computer-aided design system, which allows a high degree of freedom corresponding to the various pattern design demands. The approach basically involves the hydrothermal growth of TiO2 nanorod arrays on a transparent conductive substrate, the micropattern of TiO2 nanorod arrays and surface fluorination treatment. With these micro/nano-composite TiO2 nanorod array based films, we have demonstrated superhydrophilic patterned TiO2 nanorod arrays with rapid water spreading ability and superhydrophobic patterned TiO2 nanorod arrays with an excellent droplet bouncing effect and a good self-cleaning performance. The dynamic behaviours of the water droplets observed on the patterned TiO2 nanorod arrays were demonstrated by experiments and simulated by a finite element method. The approaches we will show are expected to provide potential applications in fields such as self-cleaning, surface protection, anticrawling and microfluidic manipulation.

  8. One-Pot Hydrothermal Synthesis of Magnetite Prussian Blue Nano-Composites and Their Application to Fabricate Glucose Biosensor

    Directory of Open Access Journals (Sweden)

    Ezzaldeen Younes Jomma

    2016-02-01

    Full Text Available In this work, we presented a simple method to synthesize magnetite Prussian blue nano-composites (Fe3O4-PB through one-pot hydrothermal process. Subsequently, the obtained nano-composites were used to fabricate a facile and effective glucose biosensor. The obtained nanoparticles were characterized using transmission electron microscopy, scanning electron microscopy, Fourier-transform infrared spectroscopy, UV-vis absorbance spectroscopy, cyclic voltammetry and chronoamperometry. The resultant Fe3O4-PB nanocomposites have magnetic properties which could easily controlled by an external magnetic field and the electro-catalysis of hydrogen peroxide. Thus, a glucose biosensor based on Fe3O4-PB was successfully fabricated. The biosensor showed super-electrochemical properties toward glucose detection exhibiting fast response time within 3 to 4 s, low detection limit of 0.5 µM and wide linear range from 5 µM to 1.2 mM with sensitivity of 32 µA∙mM−1∙cm−2 and good long-term stability.

  9. All-Polyamide Composite Coated-Fabric as an Alternative Material of Construction for Textile-Bioreactors (TBRs

    Directory of Open Access Journals (Sweden)

    Mostafa Jabbari

    2017-11-01

    Full Text Available All-polyamide composite coated-fabric (APCCF was used as an alternative material for the construction of textile-bioreactors (TBRs, which are prepared as a replacement of the traditional stainless steel bioreactors (SSBRs or concrete-based bioreactors. The material characteristics, as well as the fermentation process performance of the APCCF-TBR, was compared with a TBR made using the polyvinyl chloride (PVC-coated polyester fabric (PVCCF. The TBRs were used for the anaerobic fermentation process using baker’s yeast; and, for aerobic fermentation process using filamentous fungi, primarily by using waste streams from ethanol industries as the substrates. The results from the fermentation experiments were similar with those that were obtained from the cultivations that were carried out in conventional bioreactors. The techno-economic analysis conducted using a 5000 m3 APCCF-TBR for a typical fermentation facility would lead to a reduction of the annual production cost of the plant by $128,000,000 when compared to similar processes in SSBR. The comparative analyses (including mechanical and morphological studies, density measurements, thermal stability, ageing, and techno-economic analyses revealed that the APCCF is a better candidate for the material of construction of the TBR. As the APCCF is a 100% recyclable single-polymer composite, which was prepared from Nylon 66 textile production-line waste, it could be considered as an environmentally sustainable product.

  10. Fabrication of TiO2Nanosheet Aarrays/Graphene/Cu2O Composite Structure for Enhanced Photocatalytic Activities.

    Science.gov (United States)

    Huang, Jinzhao; Fu, Ke; Deng, Xiaolong; Yao, Nannan; Wei, Mingzhi

    2017-12-01

    TiO 2 NSAs/graphene/Cu 2 O was fabricated on the carbon fiber to use as photocastalysts by coating Cu 2 O on the graphene (G) decorated TiO 2 nanosheet arrays (NSAs). The research focus on constructing the composite structure and investigating the reason to enhance the photocatalytic ability. The morphological, structural, and photocatalytic properties of the as-synthesized products were characterized. The experimental results indicate that the better photocatalytic performance is ascribed to the following reasons. First, the TiO 2 NSAs/graphene/Cu 2 O composite structure fabricated on the carbon cloth can form a 3D structure which can provide a higher specific surface area and enhance the light absorption. Second, the graphene as an electron sink can accept the photoelectrons from the photoexcited Cu 2 O which will reduce the recombination. Third, the TiO 2 nanosheet can provide more favorable carrier transportation channel which can reduce the recombination of carriers. Finally, the Cu 2 O can extend the light absorption range.

  11. Nanotexturing of High-Performance Woven Fabrics for Novel Composite Applications

    Science.gov (United States)

    2006-11-29

    polyimides, polyetherimides, carbon fibers , silk, cellulose, wool, cotton, linen , etc… PLASMA ON Average process speed: 15 ft/min web width: >20 inches...modification of fibers and textiles has been used to increase fabric performance in areas ranging from biocidal capability to stain resistance and water...to create nanoscale chemical scaffolding and surface textures on model polyethylene films and fibers . This approach was successful at modifying the

  12. Enhancement of flame retardancy and water repellency properties of cotton fabrics using silanol based nano composites.

    Science.gov (United States)

    Mohamed, Amina L; El-Sheikh, Manal A; Waly, Ahmed I

    2014-02-15

    Environmental concerns related to fluorinated and organophosphorus compounds led to a consideration of the methods for imparting flame retardancy and water/oil repellency to textiles. A simple and facile method for fabricating the cotton fabric with superhydrophobicity and flame retardancy is described in the present work. Complex coating with amino-functionalized silica nano-particles on epoxy-functionalized cotton accompanied with ZnO nano-particles coating are carried out. In This context, new preparation techniques were used to prepare both aminated silica and ZnO nano-particles. The particle size was investigated using Transition Electron Microscope (TEM) and the chemical structure was investigated using FT-IR analysis and other analytical techniques. Cotton was functionalized with epoxy and carboxyl via grafting cotton with nano-emulsion consisted of mixture of glycidyl methacrylate (GMA) and acrylic acid (AA), and then treated for functional finishing through conventional pad-dry-cure method. The treated fabrics showed good water repellency and excellent flame retardant properties as determined by the standard test methods. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Novel powder/solid composites possessing low Young’s modulus and tunable energy absorption capacity, fabricated by electron beam melting, for biomedical applications

    International Nuclear Information System (INIS)

    Ikeo, Naoko; Ishimoto, Takuya; Nakano, Takayoshi

    2015-01-01

    Highlights: • We fabricated novel porous composites by electron beam melting. • The composites consist of necked powder and melted solid framework. • Unmelted powder that is usually discarded was mechanically functionalized by necking. • The composites possess controllably low Young’s modulus and excellent toughness. • The composites would be promising for utilization in biomedical applications. - Abstract: A novel, hierarchical, porous composite from a single material composed of necked powder and melted solid, with tunable mechanical properties, is fabricated by electron beam melting and subsequent heat treatment. The composite demonstrates low Young’s modulus (⩽31 GPa) and excellent energy absorption capacity, both of which are necessary for use in orthopedic applications. To the best of our knowledge, this is the first report on the synthesis of a material combining controllably low Young’s modulus and excellent toughness

  14. Optimal Composite Material for Low Cost Fabrication of Large Composite Aerospace Structures using NASA Resins or POSS Nanoparticle Modifications

    Science.gov (United States)

    Lamontia, Mark A.; Gruber, Mark B.; Jensen, Brian J.

    2006-01-01

    Thermoplastic laminates in situ consolidated via tape or tow placement require full mechanical properties. Realizing full properties requires resin crystallinity to be controlled - partial crystallinity leads to unacceptably low laminate compression properties. There are two approaches: utilize an amorphous matrix resin; or place material made from a semi-crystalline resin featuring kinetics faster than the process. In this paper, a matrix resin evaluation and trade study was completed with commercial and NASA amorphous polyimides on the one hand, and with PEKK mixed with POSS nanoparticles for accelerated crystallinity growth on the other. A new thermoplastic impregnated material, 6 mm wide (0.25-in) AS-4 carbon/LaRC(TradeMark)8515 dry polyimide tow, was fabricated. Since LaRC(TradeMark)8515 is fully amorphous, it attains full properties following in situ consolidation, with no post processing required to build crystallinity. The tow in situ processing was demonstrated via in situ thermoplastic filament winding it into rings.

  15. Composite film fabricated on biomedical material with corona streamer plasma processing to mitigate bacterial adhesion

    Science.gov (United States)

    Alhamarneh, Ibrahim; Pedrow, Patrick; Eskhan, Asma; Abu-Lail, Nehal

    2011-10-01

    Composite films might control bacterial adhesion and concomitant biofouling that afflicts biomedical materials. Different size molecules of polyethylene glycol (PEG) with nominal molecular weights 600, 2000, and 20000 g/mol were used to synthesize composite films with plasma processing and dip-coating procedures on surgical-grade 316L stainless steel. Before dip-coating, the substrate was pre-coated with plasma-polymerized di(ethylene glycol) vinyl ether (pp-EO2V) in an atmospheric pressure corona streamer plasma reactor. The PEG dip-coating step followed immediately in the same chamber due to the finite lifetime of radicals associated with freshly deposited pp-EO2V. Morphology of the composite film was investigated with an ESEM. FTIR confirmed incorporation of pp-EO2V and PEG species into the composite film. More investigations on the composite film were conducted by XPS measurements. Adhesion of the composite film was evaluated with a standard peel-off test. Stability of the composite film in buffer solution was evaluated by AFM. AFM was also used to measure the film roughness and thickness. Polar and non-polar contact angle measurements were included.

  16. Fabrication of flower-like tin/carbon composite microspheres as long-lasting anode materials for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Tae-Woo [Department of Chemical Engineering, College of Engineering, Hanyang University, Seoul, 133-791 (Korea, Republic of); Lim, Hyung-Seok [Department of WCU Engineering, College of Engineering, Hanyang University, Seoul, 133-791 (Korea, Republic of); Park, Seong-Jin [Department of Chemical Engineering, College of Engineering, Hanyang University, Seoul, 133-791 (Korea, Republic of); Sun, Yang-Kook [Department of WCU Engineering, College of Engineering, Hanyang University, Seoul, 133-791 (Korea, Republic of); Suh, Kyung-Do, E-mail: kdsuh@hanyang.ac.kr [Department of Chemical Engineering, College of Engineering, Hanyang University, Seoul, 133-791 (Korea, Republic of)

    2017-01-01

    In this work, we report the fabrication of the flower-like tin/carbon (Sn/C) composite microspheres using sulfonated semi-interpenetrating polystyrene (SPS) microspheres as a carbon precursor. The sulfonation degree of SPS has great effects on the resulting particle size, morphology, amount of introduced Sn, and the carbonization yield of the microspheres after heat treatment. The obtained Sn/C composite microspheres were characterized by scanning electron microscopy (SEM), focused-ion beam SEM, and X-ray diffraction. The flower-like Sn/C composite electrodes exhibited higher charge-discharge capacities than those of graphite as an anode material for a lithium ion battery. In addition, they show a long lasting cyclability, even through 400 cycles. - Highlights: • Tin nanocrystals are introduced in flower-like carbon spheres with many ripples. • Long lasting cyclability is exhibited at 1 C rate up to 400 cycles. • Tin content of composite spheres depends on chemical treatment of polymer microspheres.

  17. Structural characterization, formation mechanism and stability of curcumin in zein-lecithin composite nanoparticles fabricated by antisolvent co-precipitation.

    Science.gov (United States)

    Dai, Lei; Sun, Cuixia; Li, Ruirui; Mao, Like; Liu, Fuguo; Gao, Yanxiang

    2017-12-15

    Curcumin (Cur) exhibits a range of bioactive properties, but its application is restrained due to its poor water solubility and sensitivity to environmental stresses. In this study, zein-lecithin composite nanoparticles were fabricated by antisolvent co-precipitation technique for delivery of Cur. The result showed that the encapsulation efficiency of Cur was significantly enhanced from 42.03% in zein nanoparticles to 99.83% in zein-lecithin composite nanoparticles. The Cur entrapped in the nanoparticles was in an amorphous state confirmed by differential scanning calorimetry and X-ray diffraction. Fourier transform infrared analysis revealed that hydrogen bonding, electrostatic interaction and hydrophobic attraction were the main interactions among zein, lecithin, and Cur. Compared with single zein and lecithin nanoparticles, zein-lecithin composite nanoparticles significantly improved the stability of Cur against thermal treatment, UV irradiation and high ionic strength. Therefore, zein-lecithin composite nanoparticles could be a potential delivery system for water-insoluble bioactive compounds with enhanced encapsulation efficiency and chemical stability. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Fabrication and characterization dye sensitized solar cell (DSSC) based on TiO2/SnO2 composite

    Science.gov (United States)

    Musyaro'ah, Huda, Ichsanul; Indayani, Wahyu; Gunawan, Bodi; Yudhoyono, G.; Endarko

    2017-01-01

    Dye-sensitized solar cell (DSSC) based on TiO2/SnO2 composite electrode has been fabricated. In this research, modifications TiO2 electrode in the form of composite TiO2/SnO2 which aims to optimize the process of transfer and charge separation that reduces premature recombination in the cells, so as to increase the conversion efficiency and stability of dye-sensitized solar cell performance. In this study, DSSC is composed of several components, among others, a semiconductor oxide, a layer of dye, a counter electrode, and an electrolyte. This study used three types of semiconductors at the working electrode is pure TiO2, composite TiO2/SnO2 and pure SnO2, electrolyte gel based polymer PEG with BM 1000, plate carbon as the counter electrode (cathode), and the use of dye from synthetic materials N-749 as dye sensitizer. This study tested with xenon lamp light source intensity of 100mW/cm2. Results of research and calculations showed that the DSSC based composite electrode TiO2/SnO2 better than the DSSC based pure TiO2 electrodes and based pure SnO2 electrodes, this is indicated by the value efficient as follows: 0.041%, 0.019%, and 0.0114%.

  19. Fabrication of γ-MnS/rGO composite by facile one-pot solvothermal approach for supercapacitor applications

    Science.gov (United States)

    Li, Xianfu; Shen, Jianfeng; Li, Na; Ye, Mingxin

    2015-05-01

    γ-MnS/reduced graphene oxide (γ-MnS/rGO) composite was successfully fabricated via a facile one-pot solvothermal route using graphene oxide (GO), thioacetamide (TAA, CH3CSNH2) and MnCl2·4H2O as reactants. It reveals that TAA plays an important role in reducing GO and sulfurizing γ-MnS. The synthesized composite was characterized via X-ray diffraction and scanning electron microscopy for structural and morphological studies. Electrochemical performance was also investigated through cyclic voltammetry and galvanostatic charge-discharge. As for the application of supercapacitors, the γ-MnS/rGO composite shows a great value of 802.5 F g-1 at a current density of 5 A g-1. Furthermore, the capacitance of γ-MnS/rGO has no decrease of its initial values after 2000 cycles. The galvanostatic charge-discharge curve demonstrates the ideal capacitive behavior of γ-MnS/rGO composite electrodes.

  20. Coated protein nanoclusters from influenza H7N9 HA are highly immunogenic and induce robust protective immunity.

    Science.gov (United States)

    Wang, Li; Chang, Timothy Z; He, Yuan; Kim, Jong R; Wang, Shelly; Mohan, Teena; Berman, Zachary; Tompkins, S Mark; Tripp, Ralph A; Compans, Richard W; Champion, Julie A; Wang, Bao-Zhong

    2017-01-01

    Recurring influenza viruses pose an annual threat to public health. A time-saving, cost-effective and egg-independent influenza vaccine approach is important particularly when responding to an emerging pandemic. We fabricated coated, two-layer protein nanoclusters from recombinant trimeric hemagglutinin from an avian-origin H7N9 influenza A virus as an approach for vaccine development in response to an emerging pandemic. Assessment of the virus-specific immune responses and protective efficacy in mice immunized with the nanoclusters demonstrated that the vaccine candidates were highly immunogenic, able to induce protective immunity and long-lasting humoral antibody responses to this virus without the use of adjuvants. Because the advantages of the highly immunogenic coated nanoclusters also include rapid productions in an egg-independent system, this approach has great potential for influenza vaccine production not only in response to an emerging pandemic, but also as a replacement for conventional seasonal influenza vaccines. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Development of budesonide nanocluster dry powder aerosols: preformulation.

    Science.gov (United States)

    El-Gendy, Nashwa; Selvam, Parthiban; Soni, Pravin; Berkland, Cory

    2012-09-01

    Wet milling was previously demonstrated as a simple process for producing agglomerates of budesonide nanoparticles (also known as NanoClusters) for use in dry powder aerosol formulation. The resulting budesonide NanoCluster powders exhibited a large emitted fraction and a high fine particle fraction (FPF) from a Monodose® dry powder inhaler. In this work, excipients were added premilling or postmilling and the performance of budesonide NanoCluster dry powders was investigated. Sodium chloride, Pluronic®, or ethanol was added prior to milling due to their ability to modify surface tension or ionic strength and thereby affect the attrition/agglomeration process. Lactose or l-leucine was added after milling because these are known to modify powder flow and dispersion. The chemical stability of budesonide was maintained in all cases, but the physical aerosol properties changed substantially with the addition of excipients. In all cases, the addition of excipients led to an increase in the size of the budesonide NanoClusters and tended to reduce the emitted fraction and FPF. Titrating excipients may provide a means to discretely modify the aerosol properties of budesonide NanoClusters but did not match the performance of excipient-free NanoCluster powder. Copyright © 2012 Wiley Periodicals, Inc.

  2. Controlled nanoclustering of magnetic nanoparticles using telechelic polysiloxane and disiloxane

    Science.gov (United States)

    Thong-On, Bandit; Rutnakornpituk, Boonjira; Wichai, Uthai; Rutnakornpituk, Metha

    2015-06-01

    Diacrylate-terminated polydimethylsiloxane (PDMS) and disiloxane were synthesized and used for controlling degree of nanoclustering of magnetite nanoparticles (MNPs). PDMS was synthesized via a ring-opening polymerization of octamethylcyclotetrasiloxane (D4), followed by end functionalization with diacrylate groups. Diacrylate-terminated disiloxane was separately synthesized in a similar fashion without the use of D4 in the reaction. They were then reacted with amino-coated MNPs to obtain MNP-embedded siloxane nanoclusters. Transmission electron microscopy showed the formation of MNP-siloxane nanoclusters with the size of 70-200 nm. Degree of MNP nanoclustering can be adjusted by varying the MNP-to-siloxane ratio to obtain hydrodynamic size ranging from 200 to 2400 nm. Using the same ratio of MNPs to the siloxanes, PDMS resulted in the nanoclusters with smaller D h and more stable in toluene than those coated with disiloxane. These novel nanoclusters with controllable size might be ideal candidates for biomedical and other advanced applications after suitable surface modification.

  3. Tailoring the magnetic properties of cobalt-ferrite nanoclusters

    Science.gov (United States)

    de la Vega, A. Estrada; Garza-Navarro, M. A.; Durán-Guerrero, J. G.; Moreno Cortez, I. E.; Lucio-Porto, R.; González-González, V.

    2016-01-01

    In this contribution, we report on the tuning of magnetic properties of cobalt-ferrite nanoclusters. The cobalt-ferrite nanoclusters were synthesized from a two-step approach that consists of the synthesis of cobalt-ferrite nanoparticles in organic media, followed by their dispersion into aqueous dissolution to form an oil-in-water emulsion. These emulsions were prepared at three different concentrations of the cationic surfactant cetyltrimethylammonium bromide (CTAB), in order to control the size and clustering density of the nanoparticles in the nanoclusters. The synthesized samples were characterized by transmission electron microscopy and their related techniques, such as bright-field and Z-contrast imaging, electron diffraction and energy-dispersive X-ray spectrometry; as well as static magnetic measures. The experimental evidence indicates that the size, morphology, and nanoparticles clustering density in the nanoclusters is highly dependent of the cobalt-ferrite:CTAB molar ratio that is used in their synthesis. In addition, due to the clustering of the nanoparticles into the nanoclusters, their magnetic moments are blocked to relax cooperatively. Hence, the magnetic response of the nanoclusters can be tailored by controlling the size and nanoparticles clustering density.

  4. Tailoring the magnetic properties of cobalt-ferrite nanoclusters

    Energy Technology Data Exchange (ETDEWEB)

    Vega, A. Estrada de la; Garza-Navarro, M. A., E-mail: marco.garzanr@uanl.edu.mx; Durán-Guerrero, J. G.; Moreno Cortez, I. E.; Lucio-Porto, R.; González-González, V. [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica (Mexico)

    2016-01-15

    In this contribution, we report on the tuning of magnetic properties of cobalt-ferrite nanoclusters. The cobalt-ferrite nanoclusters were synthesized from a two-step approach that consists of the synthesis of cobalt-ferrite nanoparticles in organic media, followed by their dispersion into aqueous dissolution to form an oil-in-water emulsion. These emulsions were prepared at three different concentrations of the cationic surfactant cetyltrimethylammonium bromide (CTAB), in order to control the size and clustering density of the nanoparticles in the nanoclusters. The synthesized samples were characterized by transmission electron microscopy and their related techniques, such as bright-field and Z-contrast imaging, electron diffraction and energy-dispersive X-ray spectrometry; as well as static magnetic measures. The experimental evidence indicates that the size, morphology, and nanoparticles clustering density in the nanoclusters is highly dependent of the cobalt-ferrite:CTAB molar ratio that is used in their synthesis. In addition, due to the clustering of the nanoparticles into the nanoclusters, their magnetic moments are blocked to relax cooperatively. Hence, the magnetic response of the nanoclusters can be tailored by controlling the size and nanoparticles clustering density.

  5. Effect of thermal treatment on the growth, structure and luminescence of nitride-passivated silicon nanoclusters

    Directory of Open Access Journals (Sweden)

    Normand Elise

    2011-01-01

    Full Text Available Abstract Silicon nanoclusters (Si-ncs embedded in silicon nitride films have been studied to determine the effects that deposition and processing parameters have on their growth, luminescent properties, and electronic structure. Luminescence was observed from Si-ncs formed in silicon-rich silicon nitride films with a broad range of compositions and grown using three different types of chemical vapour deposition systems. Photoluminescence (PL experiments revealed broad, tunable emissions with peaks ranging from the near-infrared across the full visible spectrum. The emission energy was highly dependent on the film composition and changed only slightly with annealing temperature and time, which primarily affected the emission intensity. The PL spectra from films annealed for duration of times ranging from 2 s to 2 h at 600 and 800°C indicated a fast initial formation and growth of nanoclusters in the first few seconds of annealing followed by a slow, but steady growth as annealing time was further increased. X-ray absorption near edge structure at the Si K- and L3,2-edges exhibited composition-dependent phase separation and structural re-ordering of the Si-ncs and silicon nitride host matrix under different post-deposition annealing conditions and generally supported the trends observed in the PL spectra.

  6. Fabrication and properties of ceramic composites with a boron nitride matrix

    International Nuclear Information System (INIS)

    Kim, D.P.; Cofer, C.G.; Economy, J.

    1995-01-01

    Boron nitride (BN) matrix composites reinforced by a number of different ceramic fibers have been prepared using a low-viscosity, borazine oligomer which converts in very high yield to a stable BN matrix when heated to 1,200 C. Fibers including Nicalon (SiC), FP (Al 2 O 3 ), Sumica and Nextel 440 (Al 2 O 3 -SiO 2 ) were evaluated. The Nicalon/BN and Sumica/BN composites displayed good flexural strengths of 380 and 420 MPa, respectively, and modulus values in both cases of 80 GPa. On the other hand, FP/BN and Nextel/BN composites exhibited very brittle behavior. Nicalon fiber with a carbon coating as a buffer barrier improved the strength by 30%, with a large amount of fiber pullout from the BN matrix. In all cases except for Nicalon, the composites showed low dielectric constant and loss

  7. Evaluation of Carbon Composite Vessels Fabrication using Ionic Liquid Epoxies for Cryogenic Liquid Containment

    Data.gov (United States)

    National Aeronautics and Space Administration — The intent of the work proposed here is to ascertain the viability of ionic liquid (IL) epoxy based carbon fiber composites for use as storage tanks at cryogenic...

  8. Toughened and corrosion- and wear-resistant composite structures and fabrication methods thereof

    Science.gov (United States)

    Seals, Roland D.; Ripley, Edward B.; Hallman, Russell L.

    2017-06-20

    Composite structures having a reinforced material interjoined with a substrate, wherein the reinforced material comprises a compound selected from the group consisting of titanium monoboride, titanium diboride, and combinations thereof.

  9. Defect analysis in drilling needle-punched carbon–carbon composites perpendicular to nonwoven fabrics

    Directory of Open Access Journals (Sweden)

    Chenwei Shan

    2015-08-01

    Full Text Available Carbon–carbon composites are unique materials consisting of carbon fibers embedded in a carbonaceous matrix. Drilling of carbon–carbon composites is difficult to carry out due to the anisotropic, high specific stiffness and brittleness, nonhomogeneous inner structure of composites, and high abrasiveness of their reinforcing constituents. These typically result in defects being introduced into the workpiece and in very rapid wear development in the drilling tool. Defects are the undesired effects of machining using nonappropriate drilling parameters or worn drill. Aimed at this issue, first, the major defects caused in drilling needle-punched carbon–carbon composites are analyzed in detail. Second, the fiber fuzz factor and the ripping factor of fibers are defined to depict the drilling defects. Experiments are carried out using a conventional twist drill, and the results indicate that material structures, federates, and cutting speeds are reckoned to be the most significant factors contributing to defects.

  10. Fabrication and Characterization of Ni-CNT Composites by Electrical Explosion of Wire in Different Liquids

    Directory of Open Access Journals (Sweden)

    Thuyet-Nguyen M.

    2017-06-01

    Full Text Available In this study, Ni-CNT powders and colloids were synthesized via the Electrical explosion of wire (EEW in different liquid conditions. The influence of ambient solvents (D.I. Water, ethanol, methanol, acetone and ethylene-glycol on characteristics of the as-synthesized Ni-CNT was investigated. The morphology and size were observed by field emission scanning electron microscopy (FE-SEM. The Ni particles were spherical or near spherical shape. The phase of the composite powders analyzed via X-ray diffraction demonstrate the presence of CNTs in composite powders is not affect the structure of Ni. However, the phase of the composites was changed based on the changing of liquid conditions. Stability of colloids was investigated by Turbiscan technique. Magnetic properties were also investigated by Vibrating sample magnetometer (VSM at room temperature. The as-synthesized composite powders revealed a ferromagnetic characteristic material.

  11. Fabrication of carbon nanofiber-reinforced aluminum matrix composites assisted by aluminum coating formed on nanofiber surface by in situ chemical vapor deposition

    Science.gov (United States)

    Ogawa, Fumio; Masuda, Chitoshi

    2015-01-01

    The van der Waals agglomeration of carbon nanofibers (CNFs) and the weight difference and poor wettability between CNFs and aluminum hinder the fabrication of dense CNF-reinforced aluminum matrix composites with superior properties. In this study, to improve this situation, CNFs were coated with aluminum by a simple and low-cost in situ chemical vapor deposition (in situ CVD). Iodine was used to accelerate the transport of aluminum atoms. The coating layer formed by the in situ CVD was characterized using scanning electron microscopy, transmission electron microscopy, x-ray diffraction, Fourier transform-infrared spectroscopy, and x-ray photoelectron spectroscopy. The results confirmed that the CNFs were successfully coated with aluminum. The composites were fabricated to investigate the effect of the aluminum coating formed on the CNFs. The dispersion of CNFs, density, Vickers micro-hardness and thermal conductivity of the composites fabricated by powder metallurgy were improved. Pressure-less infiltration experiments were conducted to fabricate composites by casting. The results demonstrated that the wettability and infiltration were dramatically improved by the aluminum coating layer on CNFs. The aluminum coating formed by the in situ CVD technique was proved to be effective for the fabrication of CNF-reinforced aluminum matrix composites.

  12. Development and fabrication of high strength alloy fibers for use in metal-metal matrix composites

    Science.gov (United States)

    King, G. W.; Petrasek, D. W.

    1979-01-01

    Metal fiber reinforced superalloys are being considered for construction of critical components in turbine engines that operate at high temperature. The problems involved in fabricating refractory metal alloys into wire form in such a manner as to maximize their strength properties without developing excessive structural defects are described. The fundamental principles underlying the development of such alloy fibers are also briefly discussed. The progress made to date in developing tungsten, tantalum and columbium base alloys for fiber reinforcement is reported and future prospects for alloy fiber development considered.

  13. Fatigue damage propagation in unidirectional glass fibre reinforced composites made of a non-crimp fabric

    DEFF Research Database (Denmark)

    Hansen, Jens Zangenberg; Brøndsted, Povl; Gillespie Jr., John W.

    2014-01-01

    -mechanisms are examined using three distinct microscopic analyses, and the transverse crack density is measured. It is documented that the stiffness loss in fatigue is directly related to fibre fractures in the load-carrying axial fibre bundles, initialised by interface debonding and cracking in the transverse backing...... fatigue, gives rise to axial fibre fractures and a loss of stiffness, eventually leading to final failure. The uniqueness of the present work is identification of the mechanisms associated with tension fatigue failure of unidirectional non-crimp fabrics used for wind turbine blades. The observed damage...

  14. Fabrication and properties of luminescence polymer composites with erbium/ytterbium oxides and gold nanoparticles

    Directory of Open Access Journals (Sweden)

    Julia A. Burunkova

    2016-04-01

    Full Text Available Rare-earth-doped optical materials are important for light sources in optoelectronics, as well as for efficient optical amplification elements and other elements of photonics. On the basis of the previously developed method of anhydrous, low-temperature synthesis of Er/Yb oxides from their chlorides we fabricated proper nanoparticles with defined parameters and used them for the development of optically transparent, luminescent polymer nanocomposite with low optical scattering, suitable for direct, light-induced formation of photonic elements. Introduction of preformed gold nanoparticles in such a nanocomposite was also performed and an enhancement of luminescence due to the influence of plasmon effects was detected.

  15. Fabrication, microstructural characterization and wear characteristics of A380 alloy-alumina composites

    KAUST Repository

    Nurani, Sheikh Jaber

    2016-03-10

    To obtain better mechanical and tribological properties than aluminium alloys aluminium is reinforced with alumina particles making aluminium metal matrix composites. In this work scrap piston A380 alloy was used as the matrix alloy. Alumina particles were added by 5%, 10% and 15% into matrix alloy respectively to form desired composites by stir casting technique. Pin on disc wear testing machine with counter surface as steel disc of hardness HRC 32 and surface roughness of 0.62 μm was used to conduct the wear test. In result composites showed superior wear resistance property over A380 alloy. The effect of load, sliding speed and sliding distance on wear behaviour were also examined in this study. Wear mechanism was identified from the worn surface. Both optical and scanning electron microscope (SEM) of the composites was performed to determine the microstructures. Optical micrograph shows grain size decreases with addition of alumina particles. EDS analysis was performed to confirm the presence of α-Al matrix, primary Si particles and intermetallic. As a general method, phase compositions were analyzed by using a scanning electron microscope (SEM) equipped with an energy dispersive spectroscopy (EDS). Optical microstructures were consistent with the SEM micrographs. © 2015 IEEE.

  16. Density variation effects on cross dimension (cd) strength of phenolic multilayered composites fabricated via vartm

    International Nuclear Information System (INIS)

    Nasir, M.A.

    2014-01-01

    Different phenolic composites categorized on the basis of different reinforcing fibers, each fiber has a constant length of 50 mm in its respective composite grade, are investigated on the basis of varying number of piles per square area of tested zone. As the piles differ in interested zone then resultantly density is changed for each composite grade, although the resin and hardener are kept constant for each sample of tested composite type. Vacuum Assisted Resin Transfer Molding (VARTM) technique is used to synthesis all phenolic composites used in this research. During synthesis of each grade the same resin (Resole) and hardener (Rylex-30) are used in VARTM setup, however the fiber volume ratio is changed from 52-60% with respect to density range utilized in this work. Detail design description of VARTM is also discussed and optimized up to maximum scale to acquire compact, uniformly strengthen and porosity banned specimens. Cross Dimension (CD) Tensile and flexure strength variability with respect to density (changing fiber volume ratio) of each grade is viewed on experimental basis and tried to explain their behavior. (author)

  17. Characterization and Formability of Titanium/Aluminum Laminate Composites Fabricated by Hot Pressing

    Science.gov (United States)

    Qin, Liang; Wang, Hui; Cui, Shengqiang; Wu, Qian; Fan, Minyu; Yang, Zonghui; Tao, Jie

    2017-07-01

    The Ti/Al laminate composites were prepared by hot pressing to investigate the forming performance due to the corresponding potential applications in both the aerospace and auto industry. The bonding interface morphology and element distributions were characterized by SEM and EDS. The phase constituent was detected by XRD. It was observed that these composites presented good bonding interfaces between Ti and Al layers, and no low-sized voids and intermetallic compounds formed at the interface. In addition, the formability of these laminate composites was studied by the uniaxial tension tests, the limit drawing ratio (LDR) and the forming limit curve (FLC) experiments, respectively. The results indicated that the flow stress increased along with the strain rate increment. A constitutive equation was developed for deformation behavioral description of these laminate composites. The LDR value was 1.8, and the most susceptible region to present cracks was located at the punch profile radius. The forming limit curve of the laminate composites was located between the curves of titanium and aluminum and intersected with the major strain line at approximately 0.31. The macroscopic cracks of the FLC sample demonstrated a saw-toothed crack feature.

  18. Fabrication of Coupling Structure and Composite Properties by Electro-brush Plating and Laser Processing

    Directory of Open Access Journals (Sweden)

    LI Jing

    2016-12-01

    Full Text Available To obtain a superhydrophobic aluminum alloy surface, a kind of special coupling structure was fabricated on the aluminum alloy surface by a couple ways which was electro-brush plating combined with laser processing. The surface has excellent anti-adhesion and corrosion resistance property. The contact angle can reach as high as 155.1°, while the sliding angle less than 5.6°. The morphological feature, chemical structures, and wettability of resultant surfaces were characterized by scanning electronic microscope (SEM, X-ray diffraction (XRD and water contact angle measurements. The surface corrosion resistance was researched by a corrosion resistance experiment. The results show that surface consists of micro-scale grooves and like-cauliflower mastoids, the grooves in a regular arrangement with mastoid structures for a coupling structure on the surface. The special coupling structure makes the surface already have superhydrophobicity. The wettability of the surface changes from hydrophilicity to superhydrophobicity. There have no peaks from other phases can be detected between electro-brush plating surface and aluminum alloy substrates. The peak intensity is changed by laser processing, and the organization structure of the material is further refined. The corrosion resistance of the surface that is fabricated by couple ways improves.

  19. Design, Fabrication, and Testing of Composite Energy-Absorbing Keel Beams for General Aviation Type Aircraft

    Science.gov (United States)

    Kellas, Sotiris; Knight, Norman F., Jr.

    2002-01-01

    A lightweight energy-absorbing keel-beam concept was developed and retrofitted in a general aviation type aircraft to improve crashworthiness performance. The energy-absorbing beam consisted of a foam-filled cellular structure with glass fiber and hybrid glass/kevlar cell walls. Design, analysis, fabrication and testing of the keel beams prior to installation and subsequent full-scale crash testing of the aircraft are described. Factors such as material and fabrication constraints, damage tolerance, crush stress/strain response, seat-rail loading, and post crush integrity, which influenced the course of the design process are also presented. A theory similar to the one often used for ductile metal box structures was employed with appropriate modifications to estimate the sustained crush loads for the beams. This, analytical tool, coupled with dynamic finite element simulation using MSC.Dytran were the prime design and analysis tools. The validity of the theory as a reliable design tool was examined against test data from static crush tests of beam sections while the overall performance of the energy-absorbing subfloor was assessed through dynamic testing of 24 in long subfloor assemblies.

  20. Mechanical properties, mineralogical composition, and micro fabric of Opalinus Clay. Sandy and shaly facies (Mont Terri, Switzerland)

    Energy Technology Data Exchange (ETDEWEB)

    Kaufhold, Annette; Graesle, Werner [BGR Hannover (Germany); Plischke, Ingo

    2015-07-01

    For the safe disposal of high-level radioactive waste, different host rocks are currently considered. The favorable properties of claystone are low permeability, retention capacity for some radionuclides, and the ability to self-seal cracks, e.g. by swelling or time-dependent compaction creep. For the understanding of the long-term behavior of clay host rocks, the interaction between mechanical behavior, micro fabric, and mineral composition has to be understood (Bock et al., 2010). In the international research project Mont Terri (Switzerland) the Opalinus Clay (Jurassic Formation) is investigated in an underground rock laboratory (URL). In the present study the relationship between mechanical, mineralogical and micro fabric properties were studied on representative samples of the sandy and shaly facies of the Opalinus Clay (OPA) from Mont Terri. The mineral composition of all samples was analysed by using a complex mineral phase analysis. Therefore, the results of the X-ray diffraction, X-ray fluoreszence, organic and inorganic carbonate analysis (LECO) were adjusted with each other. In the case of the sandy facies (OPA) the mechanical strength inrcreases with increasing carbonate content. Here small carbonate particles form the matrix and act as stabilisator. The carbonates of the shaly facies (OPA), on the other hand, are mainly fossil fragments (e.g. shells) aligned parallel to bedding. These large carbonate particles are acting as predetermined breaking surfaces. Hence, in the case of shaly facies (OPA) the mechanical strength decreases with increasing carbonate content. Image Analyses (Fiji {sup registered}) of scattering electron microscope images of polished sections proved the determined microstructural differences. Besides, carbonate particles in the sandy facies are mostly isometric, in contrast carbonates of the shaly facies show different shapes. This is explained further in terms of the aspect ratio. The mechanical tests were carried out as triaxial

  1. Fabrication of composite microstructures by capillarity-driven wetting of aligned carbon nanotubes with polymers

    Energy Technology Data Exchange (ETDEWEB)

    GarcIa, E J [Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Hart, A J [Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Wardle, B L [Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Slocum, A H [Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

    2007-04-25

    The interaction, or wetting, of long aligned carbon nanotube (CNT) forests with off-the-shelf (no solvent added) commercial thermoset polymers is investigated experimentally. A technique for creating vertically aligned CNT composite microstructures of various shapes is presented. The effective wetting of the forests, as evidenced by a lack of voids, by three polymers with widely varying viscosities supports the feasibility of using CNT forests in large-scale hybrid advanced composite architectures. Among various routes identified for the polymer to penetrate the forest, capillarity-driven wetting along the CNT axis is the preferred route. Aligned CNT microstructures are useful in many applications including test structures for direct mechanical and multifunctional property characterization of the aligned CNT-polymer composite materials.

  2. Fabrication of Environmentally Resistant NITE-SiC/SiC Composites

    Energy Technology Data Exchange (ETDEWEB)

    Park, J S; Jung, H C [Muroran Establishment, IEST Co., Ltd., 27-1 Mizumoto-cho, Muroran 050-8585 (Japan); Ooi, Y; Kishimoto, K; Kohyama, A, E-mail: jspark@iest.jp [OASIS, Muroran Institute of Technology, 27-1 Mizumoto-cho, Muroran 050-8585 (Japan)

    2011-10-29

    NITE-SiC, SiC/SiC qualification of environmental resistance in various conditions is on-going toward early utilization in advanced energy and aero-space systems. Multi-layered SiC/SiC composites for preventing environmental attacks to pyrocarbon interphase was provided. Thermal exposure test in air and liquid metal(Pb and Li-Pb) compatibility test were carried out. It was confirmed the significant loss of PyC interphase in SiC/SiC composites. In case of Li-Pb-layered SiC/SiC composites, an attack of air and liquid metal has been sucessfuly supressed by surface SiC layer

  3. Fabrication of fiber composites with a MAX phase matrix by reactive melt infiltration

    International Nuclear Information System (INIS)

    Lenz, F; Krenkel, W

    2011-01-01

    Due to the inherent brittleness of ceramics it is very desirable to increase the damage tolerance of ceramics. The ternary MAX phases are a promising group of materials with high fracture toughness. The topic of this study is the development of ceramic matrix composites (CMCs) with a matrix containing MAX phases, to achieve a damage tolerant structural composite material. For this purpose carbon fiber reinforced preforms with a carbon-titanium carbide matrix (C/C-TiC) were developed and infiltrated with silicon by a pressureless reactive melt infiltration. Finally liquid silicon caused the formation of SiC, TiSi 2 and Ti 3 SiC 2 in the matrix of the composite.

  4. Failure behavior / characteristics of fabric reinforced polymer matrix composite and aluminum6061 on dynamic tensile loading

    Energy Technology Data Exchange (ETDEWEB)

    Bang, Hyejin; Cho, Chongdu [Inha University, Incheon (Korea, Republic of)

    2017-08-15

    Composite materials are composed of multiple types of materials as reinforcement and matrix. Among them, CFRP (Carbon fiber reinforced polymer) is widely used materials in automotive and defense industry. Carbon fibers are used as a reinforcement, of which Young's modulus is in a prepreg form. In automotive industry, especially, high strain rate test is needed to measure dynamic properties, used in dynamic analysis like high inertia included simulation as a car crash. In this paper, a SHTB (Split Hopkinson tensile bar) machine is employed for estimating stress-strain curve under dynamic load condition on aluminum 6061 and CFRP. The strain rate range is about from 100 /s to 1000 /s and the number of prepreg layers of composite specimen is total eight plies which are stacked symmetrically to structure CFRP. As a result, stress / strain point data are obtained and used for simulation into stacked composites.

  5. Fabrication and characterization of silver/titanium dioxide composite nanoparticles in ethylene glycol with alkaline solution through sonochemical process.

    Science.gov (United States)

    Jhuang, Ya-Yi; Cheng, Wen-Tung

    2016-01-01

    This paper aims to study fabrication and characterization of silver/titanium oxide composite nanoparticle through sonochemical process in the presence of ethylene glycol with alkaline solution. By using ultrasonic irradiation of a mixture of silver nitrate, the dispersed TiO2 nanoparticle in ethylene glycol associated with aqueous solution of sodium oxide yields Ag/TiO2 composite nanoparticle with shell/core-type geometry. The powder X-ray diffraction (XRD) of the Ag/TiO2 composites showed additional diffraction peaks corresponding to the face-centered cubic (fcc) structure of silver crystallization phase, apart from the signals from the cores of TiO2. Transmission electron microscopy (TEM) images of Ag/TiO2 composites, which average particle size is roughly 80 nm, reveal that the titanium oxide coated by Ag nanoparticle with a grain size of about 2-5 nm. Additionally, the formation of silver nanoparticles on TiO2 was monitored by ultraviolet visible light spectrophotometer (UV-Vis). As measured the optical absorption spectra of as-synthesized Ag nanoparticle varying with time, the mechanism of surface formatting silver shell on the cores of TiO2 could be explored by autocatalytic reaction; the conversion of Ag particle from silver ion is 98% for the reaction time of 1000 s; and the activity energy of synthesizing Ag nanoparticles on TiO2 is 40 kJ/mol at temperature ranging from 5 to 25°C. Hopefully, this preliminary investigation could be used for mass production of composite nanoparticles assisted by ultrasonic chemistry in the future. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Hierarchical mesoporous bioactive glass/alginate composite scaffolds fabricated by three-dimensional plotting for bone tissue engineering

    International Nuclear Information System (INIS)

    Luo Yongxiang; Lode, Anja; Gelinsky, Michael; Wu Chengtie

    2013-01-01

    Constructing bioactive scaffolds with controllable architecture for bone tissue engineering and drug delivery still maintains a significant challenge. In this study, we have developed a composite material consisting of mesoporous bioactive glass (MBG) and concentrated alginate pastes for fabrication of hierarchical scaffolds by 3D plotting. The scaffold structure contains well-ordered nano-channels, micropores as well as controllable macropores beneficial for bone tissue engineering applications and drug delivery. The structural architecture of the scaffolds has been optimized by efficient designing of the plotting coordination. The effects of MBG on mechanical strength, apatite mineralization, cytocompatibility and drug delivery properties of the composite scaffolds have been systematically studied. Transmission electron microscopy, scanning electron microscopy and energy-dispersive spectrometry were used to characterize composition and microstructure of the composite scaffolds. The MBG/alginate pastes showed good processability in the 3D plotting process, in which stable MBG/alginate composite scaffolds with controllable architecture can be prepared. The incorporation of MBG particles significantly improved the mechanical properties and apatite-mineralization ability of alginate scaffolds as well as enhanced the attachment and alkaline phosphatase activity of human bone marrow-derived mesenchymal stem cells cultivated onto the scaffolds. Dexamethasone, used as a model drug, can be efficiently loaded in MBG particles and then incorporated into alginate scaffolds resulting in a more sustained release as a function of the MBG content. Our results have indicated that 3D-plotted MBG incorporated alginate scaffolds with well-ordered nano-pores, controllable large pores, and significantly improved physicochemical, biological and drug-delivery properties could be a platform for bone tissue engineering. (paper)

  7. Flourescent Peptide-Stabilized Silver-Nanoclusters

    DEFF Research Database (Denmark)

    Gregersen, Simon

    throughput dramatically with regards to discovery of novel ligands. Our approach employs Fmoc solid-phase peptide synthesis on a PEGA resin which allows for on-resin screening of peptide ligands which, in turn, removes the tedious and labor-intensive work-up of synthesized peptides. The method allows for on......Fluorescent probes are widely used in the fields of imaging, detection, and diagnostics, and in order to achieve methodical progress, the search for new tools is an on-going quest. Within the last few decades, few-atom noble metal nanoclusters (NCs) have gathered increasing attention due....../reorganization of the peptide to facilitate NC formation. Following an initial chelation involving the thiol-functionality of cysteine side-chains, the coordination of silver into a defined NC is expected to be the driving force of the folding process. This work also illustrates the shortcomings of MALDI-TOF mass spectrometry...

  8. Synthesis of crystalline Ge nanoclusters in PE-CVD-deposited SiO2 films

    DEFF Research Database (Denmark)

    Leervad Pedersen, T.P.; Skov Jensen, J.; Chevallier, J.

    2005-01-01

    The synthesis of evenly distributed Ge nanoclusters in plasma-enhanced chemical-vapour-deposited (PE-CVD) SiO2 thin films containing 8 at. % Ge is reported. This is of importance for the application of nanoclusters in semiconductor technology. The average diameter of the Ge nanoclusters can...

  9. Method for rapid fabrication of fiber preforms and structural composite materials

    Science.gov (United States)

    Klett, James W.; Burchell, Timothy D.; Bailey, Jeffrey L.

    1998-01-01

    A densified carbon matrix carbon fiber composite preform is made by vacuum molding an aqueous slurry of carbon fibers and carbonizable organic powder to form a molded part. The molded part is dried in an oven at 50.degree. C. for 14 hours and hot pressed at 2000 psi at 400.degree. C. for 3 hours. The hot pressed part is carbonized at 650.degree. C. under nitrogen for 3 hours and graphitized at 2400.degree. C. to form a graphitic structure in the matrix of the densified carbon matrix carbon fiber composite preform. The densified preform has a density greater than 1.1 g/cc.

  10. Fabrication of polypyrrole/graphene oxide composite nanosheets and their applications for Cr(VI removal in aqueous solution.

    Directory of Open Access Journals (Sweden)

    Shangkun Li

    Full Text Available In this paper, we report on the simple, reliable synthesis of polypyrrole (PPy/graphene oxide (GO composite nanosheets by using sacrificial-template polymerization method. Herein, MnO(2 nanoslices were chosen as a sacrificial-template to deposit PPy, which served as the oxidant as well. During the polymerization of pyrrole on surface of GO nanosheets, MnO(2 component was consumed incessantly. As a result, the PPy growing on the surface of GO nanosheets has the morphology just like the MnO(2 nanoslices. This method can provide the fabrication of PPy nanostructures more easily than conventional route due to its independence of removing template, which usually is a complex and tedious experimental process. The as-prepared PPy/GO composite nanosheets exhibited an enhanced properties for Cr(VI ions removal in aqueous solution based on the synergy effect. The adsorption capacity of the PPy/GO composite nanosheets is about two times as large as that of conventional PPy nanoparticles. We believe that our findings can open a new and effective avenue to improve the adsorption performance in removing heavy metal ions from waste water.

  11. Dynamic Shock Response of an S2 Glass/SC15 Epoxy Woven Fabric Composite Material System

    Science.gov (United States)

    Key, Christopher; Alexander, Scott; Harstad, Eric; Schumacher, Shane

    2017-06-01

    The use of S2 glass/SC15 epoxy woven fabric composite materials for blast and ballistic protection has been an area of on-going research over the past decade. In order to accurately model this material system within potential applications under extreme loading conditions, a well characterized and well understood anisotropic equation of state (EOS) is needed. This work details both an experimental program and associated analytical modelling efforts which aim to provide better physical understanding of the anisotropic EOS behavior of this material. Experimental testing focused on planar shock impact tests loading the composite to peak pressures of 15 GPa in both the through-thickness and on-fiber orientation. Test results highlighted the anisotropic response of the material and provided a basis by which the associated numeric micromechanical investigation was compared. Results of the combined experimental and numerical modelling investigation provided insights into not only the constituent material influence on the composite response but also the importance of the geometrical configuration of the plain weave microstructure and the stochastic significance of the microstructural configuration. Sandia National Laboratories is a multi-mission laboratory operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin company, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  12. The fabrication of graphene/polydopamine/nickel foam composite material with excellent electrochemical performance as supercapacitor electrode

    Science.gov (United States)

    Zheng, Yu; Lu, Shixiang; Xu, Wenguo; He, Ge; Cheng, Yuanyuan; Yu, Tianlong; Zhang, Yan

    2018-02-01

    A three dimensional composite electrode consisted of reduced graphene oxide (rGO), polydopamine (PDA) and nickel foam (NF) (rGO/PDA/NF) was fabricated by immersing NF into PDA aqueous solution and then graphene oxide (GO) suspension solution respectively, and followed by annealing treatment. During the procedure, GO was coated on NF with assistance of cohesive effect of the PDA middle film, and the reduction of GO and nitrogen doping occurred simultaneously while annealing. Through XRD analyzing, the composites GO/PDA and rGO/PDA treated in experiment are amorphous. The resulted rGO/PDA/NF composite electrode was directly applied as a supercapacitor electrode and showed excellent electrochemical performance, with a high specific capacitance of 566.9 F g-1 at 1 A g-1, the maximum energy density of 172.7 W h kg-1 and a power density of 27.2 kW kg-1 in 1 mol L-1 Na2SO4 electrolyte.

  13. Microstructure and mechanical properties of Cu/SiC metal matrix composite fabricated via friction stir processing

    International Nuclear Information System (INIS)

    Akramifard, H.R.; Shamanian, M.; Sabbaghian, M.; Esmailzadeh, M.

    2014-01-01

    Highlights: • Designing a net hole was effective to achieve uniform distribution SiC particles and prevent agglomeration of them. • SZ has fine and equiaxed grains and distribution of SiC particles in the matrix is almost uniform. • No intermetallic compound was formed after FSP. • In comparison to pure Cu, Cu/SiC composite shows higher hardness and better wear behavior. - Abstract: In the present investigation, pure Cu sheets were reinforced with 25 μm SiC particles to fabricate a composite surface layer by friction stir processing (FSP). In order to improve distribution of reinforcing SiC particles, a net of holes were designed by drill on the surface of pure Cu sheet. For evaluation of microstructure, Optical Microscope (OM) and Scanning Electron Microscope (SEM) were used. Microstructural observation confirmed fine and equiaxed grains in the stir zone (SZ) and showed that SiC particles act as heterogeneous nucleation sites in the dynamic recrystallization of Cu grains. Moreover, agglomeration of particles was not observed and fine particles had a good distribution in SZ. In the SEM micrographs, porosities were detected as microstructure defects. Microhardness measurements showed that surface hardness was two times as high as that of substrate. The rotational wear tests demonstrated that use of SiC particles enhanced wear resistance and increased average friction coefficient of pure Cu. No intermetallic compound was found in Cu/SiC composite as revealed by XRD analysis

  14. Fabrication and tribological response of aluminium 6061 hybrid composite reinforced with bamboo char and boron carbide micro-fillers

    Science.gov (United States)

    Chethan, K. N.; Pai, Anand; Keni, Laxmikant G.; Singhal, Ashish; Sinha, Shubham

    2018-02-01

    Metal matrix composites (MMCs) have a wide scope of industrial applications and triumph over conventional materials due to their light weight, higher specific strength, good wear resistance and lower coefficient of thermal expansion. The present study aims at establishing the feasibility of using Bamboo charcoal particulate and boron carbide as reinforcements in Al-6061 alloy matrix and to investigate their effect on the wear of composites taking into consideration the interfacial adhesion of the reinforcements in the alloy. Al-6061 alloy was chosen as a base metallic alloy matrix. Sun-dried bamboo canes were used for charcoal preparation with the aid of a muffle furnace. The carbon content in the charcoal samples was determined by EDS (energy dispersive spectroscopy). In present study, stir casting technique was used to prepare the samples with 1%, 2%, and 3% weight of bamboo charcoal and boron carbide with Al-6061. The fabricated composites were homogenised at 570°C for 6 hours and cooled at room temperature. Wear studies were carried out on the specimens with different speed and loads. It was found that wear rate and coefficient of friction decreased with increase in the reinforcement content.

  15. Cellular Energy Absorbing TRIP-Steel/Mg-PSZ Composite: Honeycomb Structures Fabricated by a New Extrusion Powder Technology

    Directory of Open Access Journals (Sweden)

    Ulrich Martin

    2010-01-01

    Full Text Available Lightweight linear cellular composite materials on basis of austenite stainless TRIP- (TRansformation Induced Plasticity- steel as matrix with reinforcements of MgO partially stabilized zirconia (Mg-PSZ are described. Two-dimensional cellular materials for structural applications are conventionally produced by sheet expansion or corrugation processes. The presented composites are fabricated by a modified ceramic extrusion powder technology. Characterization of the microstructure in as-received and deformed conditions was carried out by optical and scanning electron microscopy. Magnetic balance measurements and electron backscatter diffraction (EBSD were used to identify the deformation-induced martensite evolution in the cell wall material. The honeycomb composite samples exhibit an increased strain hardening up to a certain engineering compressive strain and an extraordinary high specific energy absorption per unit mass and unit volume, respectively. Based on improved property-to-weight ratio such linear cellular structures will be of interest as crash absorbers or stiffened core materials for aerospace, railway, or automotive applications.

  16. Polystyrene/nano-SiO2 composite microspheres fabricated by Pickering emulsion polymerization: Preparation, mechanisms and thermal properties

    Directory of Open Access Journals (Sweden)

    W. H. Zhang

    2012-07-01

    Full Text Available We report the preparation, mechanisms and thermal properties of core-shell structured polymer/inorganic nanoparticle composite microspheres prepared by Pickering emulsion polymerization. Stable Pickering emulsion was firstly fabricated by using surface-modified nano-SiO2 particles as stabilizer. And then, two kinds of polystyrene/nano-SiO2 (PS/SiO2 composite microspheres with different sizes and morphologies were synthesized using hydrophobic azobisisobutyronitrile (AIBN and hydrophilic ammonium persulfate (APS as initiator, respectively. The possible mechanisms of Pickering emulsion polymerization initiated by different initiators were proposed according to the results of transmission electron microscope (TEM and scanning electron microscope (SEM. The chemical structure and molecular weight of the composite microspheres were characterized by Fourier transform infrared spectroscopy (FTIR, X-ray diffractometer (XRD and gel permeation chromatography coupled with a multi-angle laser light scattering photometer (GPC-MALLS. Thermogravimetric analysis (TGA and differential scanning calorimeter (DSC were used to comparatively analyze the thermal properties of nanocomposites and corresponding pure polymer. The results indicated that the decomposition temperature and glass transition temperature (Tg of nanocomposites were elevated to a certain degree due to the existence of nano-SiO2.

  17. Effect of montmorillonite clay on flax fabric reinforced poly lactic acid composites with amphiphilic additives

    CSIR Research Space (South Africa)

    Kumar, R

    2010-01-01

    Full Text Available assessed from SEM micrographs of fractured specimens. Intercalation of MMT with 1.4 nm basal spacing was observed in the PLA matrix leading to the increased modulus and water resistance of the bio-composites. Results indicated that mandelic acid and dicumyl...

  18. Flax fiber reinforced PLA composites: studies on types of PLA and different methods of fabrication

    CSIR Research Space (South Africa)

    Kumar, R

    2011-05-01

    Full Text Available in the last decade. It is well known that natural fiber reinforced PLA composites can be prepared by solution casting cum compression molding and injection molding methods. The authors have prepared flax fiber reinforced PLA (procured from Cereplast Ltd...

  19. Hierarchically porous composites fabricated by hydrogel templating and viscous trapping techniques

    NARCIS (Netherlands)

    Thompson, Benjamin R.; Horozov, Tommy S.; Stoyanov, Simeon D.; Paunov, Vesselin N.

    2018-01-01

    Two methods for the preparation of hierarchically porous composites have been developed and explored. The first involved templating mixed slurries of hydrogel beads with two different average bead size distributions with gypsum slurry which allows for precise control over the porosity, pore size

  20. High performance poly(etherketoneketone) (PEKK) composite parts fabricated using Big Area Additive Manufacturing (BAAM) processes

    Energy Technology Data Exchange (ETDEWEB)

    Kunc, Vlastimil [ORNL; Kishore, Vidya [ORNL; Chen, Xun [ORNL; Ajinjeru, Christine [ORNL; Duty, Chad [University of Tennessee (UTK) and Oak Ridge National Laboratory (ORNL); Hassen, Ahmed A [ORNL

    2016-09-01

    ORNL collaborated with Arkema Inc. to investigate poly(etherketoneketone) (PEKK) and its composites as potential feedstock material for Big Area Additive Manufacturing (BAAM) system. In this work thermal and rheological properties were investigated and characterized in order to identify suitable processing conditions and material flow behavior for BAAM process.