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Sample records for 3d graphene foam

  1. Polymer-Enriched 3D Graphene Foams for Biomedical Applications.

    PubMed

    Wang, Jun Kit; Xiong, Gordon Minru; Zhu, Minmin; Özyilmaz, Barbaros; Castro Neto, Antonio Helio; Tan, Nguan Soon; Choong, Cleo

    2015-04-22

    Graphene foams (GFs) are versatile nanoplatforms for biomedical applications because of their excellent physical, chemical, and mechanical properties. However, the brittleness and inflexibility of pristine GF (pGF) are some of the important factors restricting their widespread application. Here, a chemical-vapor-deposition-assisted method was used to synthesize 3D GFs, which were subsequently spin-coated with polymer to produce polymer-enriched 3D GFs with high conductivity and flexibility. Compared to pGF, both poly(vinylidene fluoride)-enriched GF (PVDF/GF) and polycaprolactone-enriched GF (PCL/GF) scaffolds showed improved flexibility and handleability. Despite the presence of the polymers, the polymer-enriched 3D GF scaffolds retained high levels of electrical conductivity because of the presence of microcracks that allowed for the flow of electrons through the material. In addition, polymer enrichment of GF led to an enhancement in the formation of calcium phosphate (Ca-P) compounds when the scaffolds were exposed to simulated body fluid. Between the two polymers tested, PCL enrichment of GF resulted in a higher in vitro mineralization nucleation rate because the oxygen-containing functional group of PCL had a higher affinity for Ca-P deposition and formation compared to the polar carbon-fluorine (C-F) bond in PVDF. Taken together, our current findings are a stepping stone toward future applications of polymer-enriched 3D GFs in the treatment of bone defects as well as other biomedical applications.

  2. Formation of 3D graphene foams on soft templated metal monoliths

    NASA Astrophysics Data System (ADS)

    Tynan, Michael K.; Johnson, David W.; Dobson, Ben P.; Coleman, Karl S.

    2016-07-01

    Graphene foams are leading contenders as frameworks for polymer thermosets, filtration/pollution control and for use as an electrode material in energy storage devices, taking advantage of graphene's high electrical conductivity and the porous structure of the foam. Here we demonstrate a simple synthesis of a macroporous 3D graphene material templated from a dextran/metal salt gel, where the metal was cobalt, nickel, copper, and iron. The gel was annealed to form a metal oxide foam prior to a methane chemical vapour deposition (CVD). Cobalt metal gels were shown to afford the highest quality material as determined by electron microscopy (SEM and TEM) and Raman spectroscopy.Graphene foams are leading contenders as frameworks for polymer thermosets, filtration/pollution control and for use as an electrode material in energy storage devices, taking advantage of graphene's high electrical conductivity and the porous structure of the foam. Here we demonstrate a simple synthesis of a macroporous 3D graphene material templated from a dextran/metal salt gel, where the metal was cobalt, nickel, copper, and iron. The gel was annealed to form a metal oxide foam prior to a methane chemical vapour deposition (CVD). Cobalt metal gels were shown to afford the highest quality material as determined by electron microscopy (SEM and TEM) and Raman spectroscopy. Electronic supplementary information (ESI) available: Raman, EDX, PXRD, TGA, electrical conductivity data and SEM. See DOI: 10.1039/c6nr02455f

  3. Ag Nanoparticles-Modified 3D Graphene Foam for Binder-Free Electrodes of Electrochemical Sensors

    PubMed Central

    Han, Tao; Jin, Jianli; Wang, Congxu; Sun, Youyi; Zhang, Yinghe; Liu, Yaqing

    2017-01-01

    Ag nanoparticles-modified 3D graphene foam was synthesized through a one-step in-situ approach and then directly applied as the electrode of an electrochemical sensor. The composite foam electrode exhibited electrocatalytic activity towards Hg(II) oxidation with high limit of detection and sensitivity of 0.11 µM and 8.0 µA/µM, respectively. Moreover, the composite foam electrode for the sensor exhibited high cycling stability, long-term durability and reproducibility. These results were attributed to the unique porous structure of the composite foam electrode, which enabled the surface of Ag nanoparticles modified reduced graphene oxide (Ag NPs modified rGO) foam to become highly accessible to the metal ion and provided more void volume for the reaction with metal ion. This work not only proved that the composite foam has great potential application in heavy metal ions sensors, but also provided a facile method of gram scale synthesis 3D electrode materials based on rGO foam and other electrical active materials for various applications. PMID:28336878

  4. Ag Nanoparticles-Modified 3D Graphene Foam for Binder-Free Electrodes of Electrochemical Sensors.

    PubMed

    Han, Tao; Jin, Jianli; Wang, Congxu; Sun, Youyi; Zhang, Yinghe; Liu, Yaqing

    2017-02-16

    Ag nanoparticles-modified 3D graphene foam was synthesized through a one-step in-situ approach and then directly applied as the electrode of an electrochemical sensor. The composite foam electrode exhibited electrocatalytic activity towards Hg(II) oxidation with high limit of detection and sensitivity of 0.11 μM and 8.0 μA/μM, respectively. Moreover, the composite foam electrode for the sensor exhibited high cycling stability, long-term durability and reproducibility. These results were attributed to the unique porous structure of the composite foam electrode, which enabled the surface of Ag nanoparticles modified reduced graphene oxide (Ag NPs modified rGO) foam to become highly accessible to the metal ion and provided more void volume for the reaction with metal ion. This work not only proved that the composite foam has great potential application in heavy metal ions sensors, but also provided a facile method of gram scale synthesis 3D electrode materials based on rGO foam and other electrical active materials for various applications.

  5. Advanced Li-Ion Hybrid Supercapacitors Based on 3D Graphene-Foam Composites.

    PubMed

    Liu, Wenwen; Li, Jingde; Feng, Kun; Sy, Abel; Liu, Yangshuai; Lim, Lucas; Lui, Gregory; Tjandra, Ricky; Rasenthiram, Lathankan; Chiu, Gordon; Yu, Aiping

    2016-10-05

    Li-ion hybrid supercapacitors (LIHSs) have recently attracted increasing attention as a new and promising energy storage device. However, it is still a great challenge to construct novel LIHSs with high-performance due to the majority of battery-type anodes retaining the sluggish kinetics of Li-ion storage and most capacitor-type cathodes with low specific capacitance. To solve this problem, 3D graphene-wrapped MoO3 nanobelt foam with the unique porous network structure has been designed and prepared as anode material, which delivers high capacity, improved rate performance, and enhanced cycle stability. First-principles calculation reveals that the combination of graphene dramatically reduces the diffusion energy barrier of Li(+) adsorbed on the surface of MoO3 nanobelt, thus improving its electrochemical performance. Furthermore, 3D graphene-wrapped polyaniline nanotube foam derived carbon is employed as a new type of capacitor-type cathode, demonstrating high specific capacitance, good rate performance, and long cycle stability. Benefiting from these two graphene foam-enhanced materials, the constructed LIHSs show a wide operating voltage range (3.8 V), a long stable cycle life (90% capacity retention after 3000 cycles), a high energy density (128.3 Wh·kg(-1)), and a high power density (13.5 kW·kg(-1)). These encouraging performances indicate that the obtained LIHSs may have promising prospect as next-generation energy-storage devices.

  6. 3D Graphene-Foam-Reduced-Graphene-Oxide Hybrid Nested Hierarchical Networks for High-Performance Li-S Batteries.

    PubMed

    Hu, Guangjian; Xu, Chuan; Sun, Zhenhua; Wang, Shaogang; Cheng, Hui-Ming; Li, Feng; Ren, Wencai

    2016-02-24

    A 3D graphene-foam-reduced-graphene-oxide hybrid nested hierarchical network is synthesized to achieve high sulfur loading and content simultaneously, which solves the "double low" issues of Li-S batteries. The obtained Li-S cathodes show a high areal capacity two times larger than that of commercial lithium-ion batteries, and a good cycling performance comparable to those at low sulfur loading.

  7. Nanostructured pseudocapacitive materials decorated 3D graphene foam electrodes for next generation supercapacitors

    NASA Astrophysics Data System (ADS)

    Patil, Umakant; Lee, Su Chan; Kulkarni, Sachin; Sohn, Ji Soo; Nam, Min Sik; Han, Suhyun; Jun, Seong Chan

    2015-04-01

    Nowadays, advancement in performance of proficient multifarious electrode materials lies conclusively at the core of research concerning energy storage devices. To accomplish superior capacitance performance the requirements of high capacity, better cyclic stability and good rate capability can be expected from integration of electrochemical double layer capacitor based carbonaceous materials (high power density) and pseudocapacitive based metal hydroxides/oxides or conducting polymers (high energy density). The envisioned three dimensional (3D) graphene foams are predominantly advantageous to extend potential applicability by offering a large active surface area and a highly conductive continuous porous network for fast charge transfer with decoration of nanosized pseudocapacitive materials. In this article, we review the latest methodologies and performance evaluation for several 3D graphene based metal oxides/hydroxides and conducting polymer electrodes with improved electrochemical properties for next-generation supercapacitors. The most recent research advancements of our and other groups in the field of 3D graphene based electrode materials for supercapacitors are discussed. To assess the studied materials fully, a careful interpretation and rigorous scrutiny of their electrochemical characteristics is essential. Auspiciously, both nano-structuration as well as confinement of metal hydroxides/oxides and conducting polymers onto a conducting porous 3D graphene matrix play a great role in improving the performance of electrodes mainly due to: (i) active material access over large surface area with fast charge transportation; (ii) synergetic effect of electric double layer and pseudocapacitive based charge storing.

  8. High power density microbial fuel cell with flexible 3D graphene-nickel foam as anode.

    PubMed

    Wang, Hanyu; Wang, Gongming; Ling, Yichuan; Qian, Fang; Song, Yang; Lu, Xihong; Chen, Shaowei; Tong, Yexiang; Li, Yat

    2013-11-07

    The structure and electrical conductivity of anode play a significant role in the power generation of microbial fuel cells (MFCs). In this study, we developed a three-dimensional (3D) reduced graphene oxide-nickel (denoted as rGO-Ni) foam as an anode for MFC through controlled deposition of rGO sheets onto the nickel foam substrate. The loading amount of rGO sheets and electrode surface area can be controlled by the number of rGO loading cycles. 3D rGO-Ni foam anode provides not only a large accessible surface area for microbial colonization and electron mediators, but also a uniform macro-porous scaffold for effective mass diffusion of the culture medium. Significantly, at a steady state of the power generation, the MFC device with flexible rGO-Ni electrodes produced an optimal volumetric power density of 661 W m(-3) calculated based on the volume of anode material, or 27 W m(-3) based on the volume of the anode chamber. These values are substantially higher than that of plain nickel foam, and other conventional carbon based electrodes (e.g., carbon cloth, carbon felt, and carbon paper) measured in the same conditions. To our knowledge, this is the highest volumetric power density reported for mL-scale MFC device with a pure strain of Shewanella oneidensis MR-1. We also demonstrated that the MFC device can be operated effectively in a batch-mode at least for a week. These new 3D rGO-Ni electrodes show great promise for improving the power generation of MFC devices.

  9. Enhanced hydrogen production in microbial electrolysis cell with 3D self-assembly nickel foam-graphene cathode.

    PubMed

    Cai, Weiwei; Liu, Wenzong; Han, Jinglong; Wang, Aijie

    2016-06-15

    In comparison to precious metal catalyst especially Platinum (Pt), nickel foam (NF) owned cheap cost and unique three-dimensional (3D) structure, however, it was scarcely applied as cathode material in microbial electrolysis cell (MEC) as the intrinsic laggard electrochemical activity for hydrogen recovery. In this study, a self-assembly 3D nickel foam-graphene (NF-G) cathode was fabricated by facile hydrothermal approach for hydrogen evolution in MECs. Electrochemical analysis (linear scan voltammetry and electrochemical impedance spectroscopy) revealed the improved electrochemical activity and effective mass diffusion after coating with graphene. NF-G as cathode in MEC showed a significant enhancement in hydrogen production rate compared with nickel foam at a variety of biases. Noticeably, NF-G showed a comparable averaged hydrogen production rate (1.31 ± 0.07 mL H2 mL(-1) reactor d(-1)) to Platinum/carbon (Pt/C) (1.32 ± 0.07 mL H2 mL(-1) reactor d(-1)) at 0.8 V. Profitable energy recovery could be achieved by NF-G cathode at higher applied voltage, which performed the best hydrogen yield of 3.27 ± 0.16 mol H2 mol(-1) acetate at 0.8 V and highest energy efficiency of 185.92 ± 6.48% at 0.6 V.

  10. 3D flexible O/N Co-doped graphene foams for supercapacitor electrodes with high volumetric and areal capacitances

    NASA Astrophysics Data System (ADS)

    Qin, Tianfeng; Wan, Zunyuan; Wang, Zilei; Wen, Yuxiang; Liu, Mengting; Peng, Shanglong; He, Deyan; Hou, Juan; Huang, Fei; Cao, Guozhong

    2016-12-01

    3D flexible O/N co-doped graphene foams (GF) have been designed and fabricated successfully via combining the compression/hot curing strategy with chemical reduction and hydrothermal treatment, in which melamine foams were used not only as the source of N/O functional groups for the introduction of pseudocapacitance but also as the sacrificial template to inhibit the agglomeration of graphene. Also, the mechanism for method of the compressing/hot curing has been investigated systematically. And the resultant GF demonstrates excellent mechanical strength and flexibility. When the compacting GF is used as free-standing electrodes for supercapacitor, it exhibits more excellent ability of charge storage than that of pristine graphene foams. And 10 MPa-GF electrodes delivers high areal capacitance of 375 μF cm-2 at a current density of 1 A g-1, excellent rate capabilities and superior cycling stability of above 100%. According to the analysis of capacitance contribution for 10 MPa-GF electrode, the pseudocapacitance originated from N/O functional groups is up to ∼65% of the contribution of total capacitance. Moreover, the symmetric supercapacitor comprised of 10 MPa-GF electrodes presents a maximum energy density of 16 Wh kg-1 (8 Wh L-1) and a maximum power density of 17 kW kg-1 (8.6 kW L-1).

  11. The effect of annealing on a 3D SnO2/graphene foam as an advanced lithium-ion battery anode

    PubMed Central

    Tian, Ran; Zhang, Yangyang; Chen, Zhihang; Duan, Huanan; Xu, Biyi; Guo, Yiping; Kang, Hongmei; Li, Hua; Liu, Hezhou

    2016-01-01

    3D annealed SnO2/graphene sheet foams (ASGFs) are synthesized by in situ self-assembly of graphene sheets prepared by mild chemical reduction. L-ascorbyl acid is used to effectively reduce the SnO2 nanoparticles/graphene oxide colloidal solution and form the 3D conductive graphene networks. The annealing treatment contributes to the formation of the Sn-O-C bonds between the SnO2 nanoparticles and the reduced graphene sheets, which improves the electrochemical performance of the foams. The ASGF has features of typical aerogels: low density (about 19 mg cm−3), smooth surface and porous structure. The ASGF anodes exhibit good specific capacity, excellent cycling stability and superior rate capability. The first reversible specific capacity is as high as 984.2 mAh g−1 at a specific current of 200 mA g−1. Even at the high specific current of 1000 mA g−1 after 150 cycles, the reversible specific capacity of ASGF is still as high as 533.7 mAh g−1, about twice as much as that of SGF (297.6 mAh g−1) after the same test. This synthesis method can be scaled up to prepare other metal oxides particles/ graphene sheet foams for high performance lithium-ion batteries, supercapacitors, and catalysts, etc. PMID:26754468

  12. 3D nitrogen-doped graphene foam with encapsulated germanium/nitrogen-doped graphene yolk-shell nanoarchitecture for high-performance flexible Li-ion battery.

    PubMed

    Mo, Runwei; Rooney, David; Sun, Kening; Yang, Hui Ying

    2017-01-04

    Flexible electrochemical energy storage devices have attracted extensive attention as promising power sources for the ever-growing field of flexible and wearable electronic products. However, the rational design of a novel electrode structure with a good flexibility, high capacity, fast charge-discharge rate and long cycling lifetimes remains a long-standing challenge for developing next-generation flexible energy-storage materials. Herein, we develop a facile and general approach to three-dimensional (3D) interconnected porous nitrogen-doped graphene foam with encapsulated Ge quantum dot/nitrogen-doped graphene yolk-shell nano architecture for high specific reversible capacity (1,220 mAh g(-1)), long cycling capability (over 96% reversible capacity retention from the second to 1,000 cycles) and ultra-high rate performance (over 800 mAh g(-1) at 40 C). This work paves a way to develop the 3D interconnected graphene-based high-capacity electrode material systems, particularly those that suffer from huge volume expansion, for the future development of high-performance flexible energy storage systems.

  13. 3D nitrogen-doped graphene foam with encapsulated germanium/nitrogen-doped graphene yolk-shell nanoarchitecture for high-performance flexible Li-ion battery

    NASA Astrophysics Data System (ADS)

    Mo, Runwei; Rooney, David; Sun, Kening; Yang, Hui Ying

    2017-01-01

    Flexible electrochemical energy storage devices have attracted extensive attention as promising power sources for the ever-growing field of flexible and wearable electronic products. However, the rational design of a novel electrode structure with a good flexibility, high capacity, fast charge-discharge rate and long cycling lifetimes remains a long-standing challenge for developing next-generation flexible energy-storage materials. Herein, we develop a facile and general approach to three-dimensional (3D) interconnected porous nitrogen-doped graphene foam with encapsulated Ge quantum dot/nitrogen-doped graphene yolk-shell nano architecture for high specific reversible capacity (1,220 mAh g-1), long cycling capability (over 96% reversible capacity retention from the second to 1,000 cycles) and ultra-high rate performance (over 800 mAh g-1 at 40 C). This work paves a way to develop the 3D interconnected graphene-based high-capacity electrode material systems, particularly those that suffer from huge volume expansion, for the future development of high-performance flexible energy storage systems.

  14. 3D nitrogen-doped graphene foam with encapsulated germanium/nitrogen-doped graphene yolk-shell nanoarchitecture for high-performance flexible Li-ion battery

    PubMed Central

    Mo, Runwei; Rooney, David; Sun, Kening; Yang, Hui Ying

    2017-01-01

    Flexible electrochemical energy storage devices have attracted extensive attention as promising power sources for the ever-growing field of flexible and wearable electronic products. However, the rational design of a novel electrode structure with a good flexibility, high capacity, fast charge–discharge rate and long cycling lifetimes remains a long-standing challenge for developing next-generation flexible energy-storage materials. Herein, we develop a facile and general approach to three-dimensional (3D) interconnected porous nitrogen-doped graphene foam with encapsulated Ge quantum dot/nitrogen-doped graphene yolk-shell nano architecture for high specific reversible capacity (1,220 mAh g−1), long cycling capability (over 96% reversible capacity retention from the second to 1,000 cycles) and ultra-high rate performance (over 800 mAh g−1 at 40 C). This work paves a way to develop the 3D interconnected graphene-based high-capacity electrode material systems, particularly those that suffer from huge volume expansion, for the future development of high-performance flexible energy storage systems. PMID:28051065

  15. Bacteria-Affinity 3D Macroporous Graphene/MWCNTs/Fe3O4 Foams for High-Performance Microbial Fuel Cells.

    PubMed

    Song, Rong-Bin; Zhao, Cui-E; Jiang, Li-Ping; Abdel-Halim, Essam Sayed; Zhang, Jian-Rong; Zhu, Jun-Jie

    2016-06-29

    Promoting the performance of microbial fuel cells (MFCs) relies heavily on the structure design and composition tailoring of electrode materials. In this work, three-dimensional (3D) macroporous graphene foams incorporated with intercalated spacer of multiwalled carbon nanotubes (MWCNTs) and bacterial anchor of Fe3O4 nanospheres (named as G/MWCNTs/Fe3O4 foams) were first synthesized and used as anodes for Shewanella-inoculated microbial fuel cells (MFCs). Thanks to the macroporous structure of 3D graphene foams, the expanded electrode surface by MWCNTs spacing, as well as the high affinity of Fe3O4 nanospheres toward Shewanella oneidensis MR-1, the anode exhibited high bacterial loading capability. In addition to spacing graphene nanosheets for accommodating bacterial cells, MWCNTs paved a smoother way for electron transport in the electrode substrate of MFCs. Meanwhile, the embedded bioaffinity Fe3O4 nanospheres capable of preserving the bacterial metabolic activity provided guarantee for the long-term durability of the MFCs. With these merits, the constructed MFC possessed significantly higher power output and stronger stability than that with conventional graphite rod anode.

  16. Synthesis of ZnO nanowire arrays/3D graphene foam and application for determination of levodopa in the presence of uric acid.

    PubMed

    Yue, Hong Yan; Zhang, Hong; Huang, Shuo; Lin, Xuan Yu; Gao, Xin; Chang, Jing; Yao, Long Hui; Guo, Er Jun

    2017-03-15

    Three-dimensional (3D) graphene foam (GF) was prepared by chemical vapor deposition (CVD) using nickel foam as the template. ZnO nanowire arrays (ZnO NWAs) were vertically grown on the 3D GF by hydrothermal synthesis to prepare ZnO NWAs/GF. This hybrid combines the properties of ZnO NWAs and 3D GF, which has favorable electrocatalysis and outstanding electrical conductivity. The vertically aligned ZnO NWAs grown on the GF enlarged the electroactive surface area, which was investigated from the Fe(CN)6(3-4+) redox kinetic study. The ZnO NWAs/GF was used as an electrochemical electrode for the determination of Levodopa (LD) in the presence of uric acid (UA). The electrochemical responses of the ZnO NWAs/GF electrode were investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The results show that the sensitivity of the electrode for LD is 3.15μAμM(-1) in the concentration range of 0.05-20μM and the measured detection limit of the electrode for LD is 50nM. The electrode also shows good selectivity, reproducibility and stability. The proposed electrode is succsefully used to determine LD in human plasma samples and it is potential for use in clinical research.

  17. 3-D foam adhesive deposition

    NASA Technical Reports Server (NTRS)

    Lemons, C. R.; Salmassy, O. K.

    1976-01-01

    Bonding method, which reduces amount and weight of adhesive, is applicable to foam-filled honeycomb constructions. Novel features of process include temperature-viscosity control and removal of excess adhesive by transfer to cellophane film.

  18. Cl-Doped ZnO Nanowire Arrays on 3D Graphene Foam with Highly Efficient Field Emission and Photocatalytic Properties.

    PubMed

    Shao, Dali; Gao, Jian; Xin, Guoqing; Wang, Yiping; Li, Lu; Shi, Jian; Lian, Jie; Koratkar, Nikhil; Sawyer, Shayla

    2015-09-01

    An environmentally friendly, low-cost, and large-scale method is developed for fabrication of Cl-doped ZnO nanowire arrays (NWAs) on 3D graphene foam (Cl-ZnO NWAs/GF), and investigates its applications as a highly efficient field emitter and photocatalyst. The introduction of Cl-dopant in ZnO increases free electrons in the conduction band of ZnO and also leads to the rough surface of ZnO NWAs, which greatly improves the field emission properties of the Cl-ZnO NWAs/GF. The Cl-ZnO NWAs/GF demonstrates a low turn-on field (≈1.6 V μm(-1)), a high field enhancement factor (≈12844), and excellent field emission stability. Also, the Cl-ZnO NWAs/GF shows high photocatalytic efficiency under UV irradiation, enabling photodegradation of organic dyes such as RhB within ≈75 min, with excellent recyclability. The excellent photocatalytic performance of the Cl-ZnO NWAs/GF originates from the highly efficient charge separation efficiency at the heterointerface of Cl-ZnO and GF, as well as improved electron transport efficiency due to the doping of Cl. These results open up new possibilities of using Cl-ZnO and graphene-based hybrid nanostructures for various functional devices.

  19. 3D Printable Graphene Composite

    PubMed Central

    Wei, Xiaojun; Li, Dong; Jiang, Wei; Gu, Zheming; Wang, Xiaojuan; Zhang, Zengxing; Sun, Zhengzong

    2015-01-01

    In human being’s history, both the Iron Age and Silicon Age thrived after a matured massive processing technology was developed. Graphene is the most recent superior material which could potentially initialize another new material Age. However, while being exploited to its full extent, conventional processing methods fail to provide a link to today’s personalization tide. New technology should be ushered in. Three-dimensional (3D) printing fills the missing linkage between graphene materials and the digital mainstream. Their alliance could generate additional stream to push the graphene revolution into a new phase. Here we demonstrate for the first time, a graphene composite, with a graphene loading up to 5.6 wt%, can be 3D printable into computer-designed models. The composite’s linear thermal coefficient is below 75 ppm·°C−1 from room temperature to its glass transition temperature (Tg), which is crucial to build minute thermal stress during the printing process. PMID:26153673

  20. 3D Printing of Graphene Aerogels.

    PubMed

    Zhang, Qiangqiang; Zhang, Feng; Medarametla, Sai Pradeep; Li, Hui; Zhou, Chi; Lin, Dong

    2016-04-06

    3D printing of a graphene aerogel with true 3D overhang structures is highlighted. The aerogel is fabricated by combining drop-on-demand 3D printing and freeze casting. The water-based GO ink is ejected and freeze-cast into designed 3D structures. The lightweight (<10 mg cm(-3) ) 3D printed graphene aerogel presents superelastic and high electrical conduction.

  1. Highly-Sensitive Surface-Enhanced Raman Spectroscopy (SERS)-based Chemical Sensor using 3D Graphene Foam Decorated with Silver Nanoparticles as SERS substrate

    PubMed Central

    Srichan, Chavis; Ekpanyapong, Mongkol; Horprathum, Mati; Eiamchai, Pitak; Nuntawong, Noppadon; Phokharatkul, Ditsayut; Danvirutai, Pobporn; Bohez, Erik; Wisitsoraat, Anurat; Tuantranont, Adisorn

    2016-01-01

    In this work, a novel platform for surface-enhanced Raman spectroscopy (SERS)-based chemical sensors utilizing three-dimensional microporous graphene foam (GF) decorated with silver nanoparticles (AgNPs) is developed and applied for methylene blue (MB) detection. The results demonstrate that silver nanoparticles significantly enhance cascaded amplification of SERS effect on multilayer graphene foam (GF). The enhancement factor of AgNPs/GF sensor is found to be four orders of magnitude larger than that of AgNPs/Si substrate. In addition, the sensitivity of the sensor could be tuned by controlling the size of silver nanoparticles. The highest SERS enhancement factor of ∼5 × 104 is achieved at the optimal nanoparticle size of 50 nm. Moreover, the sensor is capable of detecting MB over broad concentration ranges from 1 nM to 100 μM. Therefore, AgNPs/GF is a highly promising SERS substrate for detection of chemical substances with ultra-low concentrations. PMID:27020705

  2. Biochemistry-Enabled 3D Foams for Ultrafast Battery Cathodes.

    PubMed

    Zhou, Yanping; Rui, Xianhong; Sun, Wenping; Xu, Zhichuan; Zhou, Yan; Ng, Wun Jern; Yan, Qingyu; Fong, Eileen

    2015-04-28

    Metal vanadium phosphates (MVP), particularly Li3V2(PO4)3 (LVP) and Na3V2(PO4)3 (NVP), are regarded as the next-generation cathode materials in lithium/sodium ion batteries. These materials possess desirable properties such as high stability, theoretical capacity, and operating voltages. Yet, low electrical/ionic conductivities of LVP and NVP have limited their applications in demanding devices such as electric vehicles. In this work, a novel synthesis route for the preparation of LVP/NVP micro/mesoporous 3D foams via assembly of elastin-like polypeptides is demonstrated. The as-synthesized MVP 3D foams consist of microporous networks of mesoporous nanofibers, where the surfaces of individual fibers are covered with MVP nanocrystallites. TEM images further reveal that LVP/NVP nanoparticles are about 100-200 nm in diameter, with each particle enveloped by a 5 nm thick carbon shell. The MVP 3D foams prepared in this work exhibit ultrafast rate capabilities (79 mA h g(-1) at 100C and 66 mA h g(-1) at 200C for LVP 3D foams; 73 mA h g(-1) at 100C and 51 mA h g(-1) at 200C for NVP 3D foams) and excellent cycle performance (almost 100% performance retention after 1000 cycles at 100C); their properties are far superior compared to current state-of-the-art active materials.

  3. Highly compressible 3D periodic graphene aerogel microlattices

    SciTech Connect

    Zhu, Cheng; Han, T. Yong-Jin; Duoss, Eric B.; Golobic, Alexandra M.; Kuntz, Joshua D.; Spadaccini, Christopher M.; Worsley, Marcus A.

    2015-04-22

    Graphene is a two-dimensional material that offers a unique combination of low density, exceptional mechanical properties, large surface area and excellent electrical conductivity. Recent progress has produced bulk 3D assemblies of graphene, such as graphene aerogels, but they possess purely stochastic porous networks, which limit their performance compared with the potential of an engineered architecture. Here we report the fabrication of periodic graphene aerogel microlattices, possessing an engineered architecture via a 3D printing technique known as direct ink writing. The 3D printed graphene aerogels are lightweight, highly conductive and exhibit supercompressibility (up to 90% compressive strain). Moreover, the Young’s moduli of the 3D printed graphene aerogels show an order of magnitude improvement over bulk graphene materials with comparable geometric density and possess large surface areas. Ultimately, adapting the 3D printing technique to graphene aerogels realizes the possibility of fabricating a myriad of complex aerogel architectures for a broad range of applications.

  4. Highly compressible 3D periodic graphene aerogel microlattices

    NASA Astrophysics Data System (ADS)

    Zhu, Cheng; Han, T. Yong-Jin; Duoss, Eric B.; Golobic, Alexandra M.; Kuntz, Joshua D.; Spadaccini, Christopher M.; Worsley, Marcus A.

    2015-04-01

    Graphene is a two-dimensional material that offers a unique combination of low density, exceptional mechanical properties, large surface area and excellent electrical conductivity. Recent progress has produced bulk 3D assemblies of graphene, such as graphene aerogels, but they possess purely stochastic porous networks, which limit their performance compared with the potential of an engineered architecture. Here we report the fabrication of periodic graphene aerogel microlattices, possessing an engineered architecture via a 3D printing technique known as direct ink writing. The 3D printed graphene aerogels are lightweight, highly conductive and exhibit supercompressibility (up to 90% compressive strain). Moreover, the Young's moduli of the 3D printed graphene aerogels show an order of magnitude improvement over bulk graphene materials with comparable geometric density and possess large surface areas. Adapting the 3D printing technique to graphene aerogels realizes the possibility of fabricating a myriad of complex aerogel architectures for a broad range of applications.

  5. Highly compressible 3D periodic graphene aerogel microlattices

    PubMed Central

    Zhu, Cheng; Han, T. Yong-Jin; Duoss, Eric B.; Golobic, Alexandra M.; Kuntz, Joshua D.; Spadaccini, Christopher M.; Worsley, Marcus A.

    2015-01-01

    Graphene is a two-dimensional material that offers a unique combination of low density, exceptional mechanical properties, large surface area and excellent electrical conductivity. Recent progress has produced bulk 3D assemblies of graphene, such as graphene aerogels, but they possess purely stochastic porous networks, which limit their performance compared with the potential of an engineered architecture. Here we report the fabrication of periodic graphene aerogel microlattices, possessing an engineered architecture via a 3D printing technique known as direct ink writing. The 3D printed graphene aerogels are lightweight, highly conductive and exhibit supercompressibility (up to 90% compressive strain). Moreover, the Young's moduli of the 3D printed graphene aerogels show an order of magnitude improvement over bulk graphene materials with comparable geometric density and possess large surface areas. Adapting the 3D printing technique to graphene aerogels realizes the possibility of fabricating a myriad of complex aerogel architectures for a broad range of applications. PMID:25902277

  6. High surface area graphene foams by chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Drieschner, Simon; Weber, Michael; Wohlketzetter, Jörg; Vieten, Josua; Makrygiannis, Evangelos; Blaschke, Benno M.; Morandi, Vittorio; Colombo, Luigi; Bonaccorso, Francesco; Garrido, Jose A.

    2016-12-01

    Three-dimensional (3D) graphene-based structures combine the unique physical properties of graphene with the opportunity to get high electrochemically available surface area per unit of geometric surface area. Several preparation techniques have been reported to fabricate 3D graphene-based macroscopic structures for energy storage applications such as supercapacitors. Although reaserch has been focused so far on achieving either high specific capacitance or high volumetric capacitance, much less attention has been dedicated to obtain high specific and high volumetric capacitance simultaneously. Here, we present a facile technique to fabricate graphene foams (GF) of high crystal quality with tunable pore size grown by chemical vapor deposition. We exploited porous sacrificial templates prepared by sintering nickel and copper metal powders. Tuning the particle size of the metal powders and the growth temperature allow fine control of the resulting pore size of the 3D graphene-based structures smaller than 1 μm. The as-produced 3D graphene structures provide a high volumetric electric double layer capacitance (165 mF cm-3). High specific capacitance (100 Fg-1) is obtained by lowering the number of layers down to single layer graphene. Furthermore, the small pore size increases the stability of these GFs in contrast to the ones that have been grown so far on commercial metal foams. Electrodes based on the as-prepared GFs can be a boost for the development of supercapacitors, where both low volume and mass are required.

  7. High-Density 3D-Boron Nitride and 3D-Graphene for High-Performance Nano-Thermal Interface Material.

    PubMed

    Loeblein, Manuela; Tsang, Siu Hon; Pawlik, Matthieu; Phua, Eric Jian Rong; Yong, Han; Zhang, Xiao Wu; Gan, Chee Lip; Teo, Edwin Hang Tong

    2017-02-28

    Compression studies on three-dimensional foam-like graphene and h-BN (3D-C and 3D-BN) revealed their high cross-plane thermal conductivity (62-86 W m(-1) K(-1)) and excellent surface conformity, characteristics essential for thermal management needs. Comparative studies to state-of-the-art materials and other materials currently under research for heat dissipation revealed 3D-foam's improved performance (20-30% improved cooling, temperature decrease by ΔT of 44-24 °C).

  8. Green Synthesis of Porous Three-Dimensional Nitrogen-Doped Graphene Foam for Electrochemical Applications.

    PubMed

    Yu, Hua; Ye, Delai; Butburee, Teera; Wang, Lianzhou; Dargusch, Matthew

    2016-02-03

    A facile and green approach was developed for the production of porous three-dimensional (3D) nitrogen-doped graphene with a foam structure. In comparison with conventional methods, this green approach uses environmental precursors in the preparation of graphene products. The resulting crystalline graphene foam product exhibited a uniform structure with large surface area. These appealing features render the prepared graphene foam product a prospective backbone for producing 3D charge-transport networks. The 3D graphene foam products were employed as the skeleton with an interconnected network for lithium-ion batteries. The lithium-ion batteries with the 3D porous foam structure exhibit superior cycling stability and good rate capability. There is no capacity loss after 800 cycles because the capacity stabilized for the first few cycles, and the lithium-ion batteries with 3D graphene foam showed a discharge capacity of 180 mA h g(-1) at a current density of 1000 mA g(-1). This superior cycling stability and good rate capability was ascribed to the 3D structure with an interconnected porous network and the nitrogen-doping strategy for improved conductive properties of graphene foam, which produces an efficient 3D charge-transport network. The configuration of this 3D transport network in lithium-ion cells not only can improve the electron-transport efficiency but also can suppress the volume effect during charge/discharge cycling. Besides, nitrogen doping could enhance the formation of chemical bonding between carbon and the nearby nitrogen atoms, which could accelerate the diffusion of lithium ions through the whole graphene network.

  9. Highly compressible 3D periodic graphene aerogel microlattices

    DOE PAGES

    Zhu, Cheng; Han, T. Yong-Jin; Duoss, Eric B.; ...

    2015-04-22

    Graphene is a two-dimensional material that offers a unique combination of low density, exceptional mechanical properties, large surface area and excellent electrical conductivity. Recent progress has produced bulk 3D assemblies of graphene, such as graphene aerogels, but they possess purely stochastic porous networks, which limit their performance compared with the potential of an engineered architecture. Here we report the fabrication of periodic graphene aerogel microlattices, possessing an engineered architecture via a 3D printing technique known as direct ink writing. The 3D printed graphene aerogels are lightweight, highly conductive and exhibit supercompressibility (up to 90% compressive strain). Moreover, the Young’s modulimore » of the 3D printed graphene aerogels show an order of magnitude improvement over bulk graphene materials with comparable geometric density and possess large surface areas. Ultimately, adapting the 3D printing technique to graphene aerogels realizes the possibility of fabricating a myriad of complex aerogel architectures for a broad range of applications.« less

  10. Graphene originated 3D structures grown on the assembled nickel particles

    NASA Astrophysics Data System (ADS)

    Paronyan, Tereza; Harutyunyan, Avetik; Honda Research Institute USA Inc. Team

    2013-03-01

    Recently, the fabrication of various morphologies of graphene originated structures became very important due to the perspective of wide range of new applications. Particularly, free standing 3D structured graphene foams could be imperative in energy related areas . Here, we present the new approach of the CVD growth of 3D graphene network by using primarily sintered Ni particle's (~40 μm size) assembles as a template-catalyst via decomposition of low rate of CH4 at 1100° C based on synthesis method described earlier. SEM and Raman spectra analysis revealed the formation of graphene structure containing a single up to few layers grown on the sintered metal particles served as a catalyst-template. After etching the metal frame without using any support polymer, 3D free-standing graphene microporous structure was formed demonstrating high BET surface area. Two probe measurements of frame resistance were ~2-8 Ω. Our approach allows controllable tune the pore size and thereby the surface area of 3D graphene network through the variation of the template-catalyst particles size.

  11. Three-dimensional graphene foam as a biocompatible and conductive scaffold for neural stem cells

    NASA Astrophysics Data System (ADS)

    Li, Ning; Zhang, Qi; Gao, Song; Song, Qin; Huang, Rong; Wang, Long; Liu, Liwei; Dai, Jianwu; Tang, Mingliang; Cheng, Guosheng

    2013-04-01

    Neural stem cell (NSC) based therapy provides a promising approach for neural regeneration. For the success of NSC clinical application, a scaffold is required to provide three-dimensional (3D) cell growth microenvironments and appropriate synergistic cell guidance cues. Here, we report the first utilization of graphene foam, a 3D porous structure, as a novel scaffold for NSCs in vitro. It was found that three-dimensional graphene foams (3D-GFs) can not only support NSC growth, but also keep cell at an active proliferation state with upregulation of Ki67 expression than that of two-dimensional graphene films. Meanwhile, phenotypic analysis indicated that 3D-GFs can enhance the NSC differentiation towards astrocytes and especially neurons. Furthermore, a good electrical coupling of 3D-GFs with differentiated NSCs for efficient electrical stimulation was observed. Our findings implicate 3D-GFs could offer a powerful platform for NSC research, neural tissue engineering and neural prostheses.

  12. Design of advanced porous graphene materials: from graphene nanomesh to 3D architectures.

    PubMed

    Jiang, Lili; Fan, Zhuangjun

    2014-02-21

    In order to make full utilization of the high intrinsic surface area of graphene, recently, porous graphene materials including graphene nanomesh, crumpled graphene and graphene foam, have attracted tremendous attention and research interest, owing to their exceptional porous structure (high surface area, and high pore volume) in combination with the inherent properties of graphene, such as high electronic conductivity, good thermal stability, and excellent mechanical strength. Interestingly, porous graphene materials and their derivatives have been explored in a wide range of applications in the fields of electronic and photonic devices, energy storage, gas separation/storage, oil absorption and sensors. This article reviews recent progress in the synthesis, characterization, properties, and applications of porous graphene materials. We aim to highlight the importance of designing different porous structures of graphene to meet future challenges, and the trend on future design of porous graphene materials is analyzed.

  13. Synthesis and Functionalization of 3D Nano-graphene Materials: Graphene Aerogels and Graphene Macro Assemblies.

    PubMed

    Campbell, Patrick G; Worsley, Marcus A; Hiszpanski, Anna M; Baumann, Theodore F; Biener, Juergen

    2015-11-05

    Efforts to assemble graphene into three-dimensional monolithic structures have been hampered by the high cost and poor processability of graphene. Additionally, most reported graphene assemblies are held together through physical interactions (e.g., van der Waals forces) rather than chemical bonds, which limit their mechanical strength and conductivity. This video method details recently developed strategies to fabricate mass-producible, graphene-based bulk materials derived from either polymer foams or single layer graphene oxide. These materials consist primarily of individual graphene sheets connected through covalently bound carbon linkers. They maintain the favorable properties of graphene such as high surface area and high electrical and thermal conductivity, combined with tunable pore morphology and exceptional mechanical strength and elasticity. This flexible synthetic method can be extended to the fabrication of polymer/carbon nanotube (CNT) and polymer/graphene oxide (GO) composite materials. Furthermore, additional post-synthetic functionalization with anthraquinone is described, which enables a dramatic increase in charge storage performance in supercapacitor applications.

  14. 3D Printed Graphene Based Energy Storage Devices.

    PubMed

    Foster, Christopher W; Down, Michael P; Zhang, Yan; Ji, Xiaobo; Rowley-Neale, Samuel J; Smith, Graham C; Kelly, Peter J; Banks, Craig E

    2017-03-03

    3D printing technology provides a unique platform for rapid prototyping of numerous applications due to its ability to produce low cost 3D printed platforms. Herein, a graphene-based polylactic acid filament (graphene/PLA) has been 3D printed to fabricate a range of 3D disc electrode (3DE) configurations using a conventional RepRap fused deposition moulding (FDM) 3D printer, which requires no further modification/ex-situ curing step. To provide proof-of-concept, these 3D printed electrode architectures are characterised both electrochemically and physicochemically and are advantageously applied as freestanding anodes within Li-ion batteries and as solid-state supercapacitors. These freestanding anodes neglect the requirement for a current collector, thus offering a simplistic and cheaper alternative to traditional Li-ion based setups. Additionally, the ability of these devices' to electrochemically produce hydrogen via the hydrogen evolution reaction (HER) as an alternative to currently utilised platinum based electrodes (with in electrolysers) is also performed. The 3DE demonstrates an unexpectedly high catalytic activity towards the HER (-0.46 V vs. SCE) upon the 1000th cycle, such potential is the closest observed to the desired value of platinum at (-0.25 V vs. SCE). We subsequently suggest that 3D printing of graphene-based conductive filaments allows for the simple fabrication of energy storage devices with bespoke and conceptual designs to be realised.

  15. 3D Printed Graphene Based Energy Storage Devices

    PubMed Central

    Foster, Christopher W.; Down, Michael P.; Zhang, Yan; Ji, Xiaobo; Rowley-Neale, Samuel J.; Smith, Graham C.; Kelly, Peter J.; Banks, Craig E.

    2017-01-01

    3D printing technology provides a unique platform for rapid prototyping of numerous applications due to its ability to produce low cost 3D printed platforms. Herein, a graphene-based polylactic acid filament (graphene/PLA) has been 3D printed to fabricate a range of 3D disc electrode (3DE) configurations using a conventional RepRap fused deposition moulding (FDM) 3D printer, which requires no further modification/ex-situ curing step. To provide proof-of-concept, these 3D printed electrode architectures are characterised both electrochemically and physicochemically and are advantageously applied as freestanding anodes within Li-ion batteries and as solid-state supercapacitors. These freestanding anodes neglect the requirement for a current collector, thus offering a simplistic and cheaper alternative to traditional Li-ion based setups. Additionally, the ability of these devices’ to electrochemically produce hydrogen via the hydrogen evolution reaction (HER) as an alternative to currently utilised platinum based electrodes (with in electrolysers) is also performed. The 3DE demonstrates an unexpectedly high catalytic activity towards the HER (−0.46 V vs. SCE) upon the 1000th cycle, such potential is the closest observed to the desired value of platinum at (−0.25 V vs. SCE). We subsequently suggest that 3D printing of graphene-based conductive filaments allows for the simple fabrication of energy storage devices with bespoke and conceptual designs to be realised. PMID:28256602

  16. 3D Printed Graphene Based Energy Storage Devices

    NASA Astrophysics Data System (ADS)

    Foster, Christopher W.; Down, Michael P.; Zhang, Yan; Ji, Xiaobo; Rowley-Neale, Samuel J.; Smith, Graham C.; Kelly, Peter J.; Banks, Craig E.

    2017-03-01

    3D printing technology provides a unique platform for rapid prototyping of numerous applications due to its ability to produce low cost 3D printed platforms. Herein, a graphene-based polylactic acid filament (graphene/PLA) has been 3D printed to fabricate a range of 3D disc electrode (3DE) configurations using a conventional RepRap fused deposition moulding (FDM) 3D printer, which requires no further modification/ex-situ curing step. To provide proof-of-concept, these 3D printed electrode architectures are characterised both electrochemically and physicochemically and are advantageously applied as freestanding anodes within Li-ion batteries and as solid-state supercapacitors. These freestanding anodes neglect the requirement for a current collector, thus offering a simplistic and cheaper alternative to traditional Li-ion based setups. Additionally, the ability of these devices’ to electrochemically produce hydrogen via the hydrogen evolution reaction (HER) as an alternative to currently utilised platinum based electrodes (with in electrolysers) is also performed. The 3DE demonstrates an unexpectedly high catalytic activity towards the HER (‑0.46 V vs. SCE) upon the 1000th cycle, such potential is the closest observed to the desired value of platinum at (‑0.25 V vs. SCE). We subsequently suggest that 3D printing of graphene-based conductive filaments allows for the simple fabrication of energy storage devices with bespoke and conceptual designs to be realised.

  17. Magnetism in a graphene-4 f -3 d hybrid system

    NASA Astrophysics Data System (ADS)

    Huttmann, Felix; Klar, David; Atodiresei, Nicolae; Schmitz-Antoniak, Carolin; Smekhova, Alevtina; Martínez-Galera, Antonio J.; Caciuc, Vasile; Bihlmayer, Gustav; Blügel, Stefan; Michely, Thomas; Wende, Heiko

    2017-02-01

    We create an interface of graphene with a metallic and magnetic support that leaves its electronic structure largely intact. This is achieved by exposing epitaxial graphene on ferromagnetic thin films of Co and Ni to vapor of the rare earth metal Eu at elevated temperatures, resulting in the intercalation of an Eu monolayer in between graphene and its substrate. The system is atomically well defined, with the Eu monolayer forming a (√{3 }×√{3 }) R 30∘ superstructure with respect to the graphene lattice. Thereby, we avoid the strong hybridization with the (Ni,Co) substrate 3 d states that otherwise drastically modify the electronic structure of graphene. This picture is suggested by our x-ray absorption spectroscopy measurements which show that after Eu intercalation the empty 2 p states of C atoms resemble more the ones measured for graphite in contrast to graphene directly bound to 3 d ferromagnetic substrates. We use x-ray magnetic circular dichroism at the Co and Ni L2 ,3 and Eu M4 ,5 as an element-specific probe to investigate magnetism in these systems. An antiferromagnetic coupling between Eu and Co/Ni moments is found, which is so strong that a magnetic moment of the Eu layer can be detected at room temperature. Density functional theory calculations confirm the antiferromagnetic coupling and provide an atomic insight into the magnetic coupling mechanism.

  18. Ultrafast Synthesis of Multifunctional N-Doped Graphene Foam in an Ethanol Flame.

    PubMed

    Du, Xusheng; Liu, Hong-Yuan; Mai, Yiu-Wing

    2016-01-26

    A hard template method to prepare N-doped graphene foams (NGF) with superfast template removal was developed through a pyrolyzing commercial polyurethane (PU) sponge coated with graphene oxide (GO) sheets in an ethanol flame. The removal of the template was fast and facile, and could be completed in less than 60 s in an open environment. The synthesized graphene foams consisted of a unique structure of 3D interconnected hollow struts with highly wrinkled surfaces, and the morphology of the hollow struts could be tuned by controlling the GO dispersion concentration. The foams showed high hydrophobicity and were used as absorbents for a variety of organic solvents and oils. The unique NGF structure afforded a high absorption rate and capacity, and a remarkable 98.7% pore volume of the foam could be utilized for absorption of hexane, exhibiting one of the highest capacity values among existing absorptive counterparts. The N-doping brought higher capacitive performance than conventional graphene foams prepared by chemical vapor deposition on nickel foam templates. The NGFs also displayed high elasticity and could recover completely after 50% compressive strain. Owing to easy availability and reduction environment of the flame, complete thermal decomposition of the PU sponge and highly porous open-cell structure, and flame resistance of the graphene foam, the present flame method was demonstrated to be a simple, effective, and ultrafast approach to fabricate ultra-low-density NGFs with good electromechanical response, excellent organic liquid absorption, and high-energy dissipation capabilities.

  19. Mechanical Properties of 3-D Printed Cellular Foams with triangular cells

    NASA Astrophysics Data System (ADS)

    Bunga, Pratap Kumar

    In the present work, poly lactic acid (PLA) is used as a model system to investigate the mechanical behavior of 3-D printed foams with triangular cells. Solid PLA tension and compression specimens and foams made of PLA were fabricated using fused deposition 3-D printing technique. The solid PLA tension specimens were characterized for their densities and found to be about 10% lower in density as compared to their bulk counter parts. The triangular foams had a relative density of about 64%. The relationships between the structure of the foams and its deformation behavior under compression along two in-plane directions were characterized. Furthermore, simple finite element models were developed to understand the observed deformation behavior of triangular foams.

  20. Preparation of Three-Dimensional Graphene Foams Using Powder Metallurgy Templates.

    PubMed

    Sha, Junwei; Gao, Caitian; Lee, Seoung-Ki; Li, Yilun; Zhao, Naiqin; Tour, James M

    2016-01-26

    A simple and scalable method which combines traditional powder metallurgy and chemical vapor deposition is developed for the synthesis of mesoporous free-standing 3D graphene foams. The powder metallurgy templates for 3D graphene foams (PMT-GFs) consist of particle-like carbon shells which are connected by multilayered graphene that shows high specific surface area (1080 m(2) g(-1)), good crystallization, good electrical conductivity (13.8 S cm(-1)), and a mechanically robust structure. The PMT-GFs did not break under direct flushing with DI water, and they were able to recover after being compressed. These properties indicate promising applications of PMT-GFs for fields requiring 3D carbon frameworks such as in energy-based electrodes and mechanical dampening.

  1. 3D printed cellular solid outperforms traditional stochastic foam in long-term mechanical response

    NASA Astrophysics Data System (ADS)

    Maiti, A.; Small, W.; Lewicki, J. P.; Weisgraber, T. H.; Duoss, E. B.; Chinn, S. C.; Pearson, M. A.; Spadaccini, C. M.; Maxwell, R. S.; Wilson, T. S.

    2016-04-01

    3D printing of polymeric foams by direct-ink-write is a recent technological breakthrough that enables the creation of versatile compressible solids with programmable microstructure, customizable shapes, and tunable mechanical response including negative elastic modulus. However, in many applications the success of these 3D printed materials as a viable replacement for traditional stochastic foams critically depends on their mechanical performance and micro-architectural stability while deployed under long-term mechanical strain. To predict the long-term performance of the two types of foams we employed multi-year-long accelerated aging studies under compressive strain followed by a time-temperature-superposition analysis using a minimum-arc-length-based algorithm. The resulting master curves predict superior long-term performance of the 3D printed foam in terms of two different metrics, i.e., compression set and load retention. To gain deeper understanding, we imaged the microstructure of both foams using X-ray computed tomography, and performed finite-element analysis of the mechanical response within these microstructures. This indicates a wider stress variation in the stochastic foam with points of more extreme local stress as compared to the 3D printed material, which might explain the latter’s improved long-term stability and mechanical performance.

  2. 3D printed cellular solid outperforms traditional stochastic foam in long-term mechanical response

    DOE PAGES

    Maiti, A.; Small, W.; Lewicki, J.; ...

    2016-04-27

    3D printing of polymeric foams by direct-ink-write is a recent technological breakthrough that enables the creation of versatile compressible solids with programmable microstructure, customizable shapes, and tunable mechanical response including negative elastic modulus. However, in many applications the success of these 3D printed materials as a viable replacement for traditional stochastic foams critically depends on their mechanical performance and micro-architectural stability while deployed under long-term mechanical strain. To predict the long-term performance of the two types of foams we employed multi-year-long accelerated aging studies under compressive strain followed by a time-temperature-superposition analysis using a minimum-arc-length-based algorithm. The resulting master curvesmore » predict superior long-term performance of the 3D printed foam in terms of two different metrics, i.e., compression set and load retention. To gain deeper understanding, we imaged the microstructure of both foams using X-ray computed tomography, and performed finite-element analysis of the mechanical response within these microstructures. As a result, this indicates a wider stress variation in the stochastic foam with points of more extreme local stress as compared to the 3D printed material, which might explain the latter’s improved long-term stability and mechanical performance.« less

  3. 3D printed cellular solid outperforms traditional stochastic foam in long-term mechanical response

    SciTech Connect

    Maiti, A.; Small, W.; Lewicki, J.; Weisgraber, T. H.; Duoss, E. B.; Chinn, S. C.; Pearson, M. A.; Spadaccini, C. M.; Maxwell, R. S.; Wilson, T. S.

    2016-04-27

    3D printing of polymeric foams by direct-ink-write is a recent technological breakthrough that enables the creation of versatile compressible solids with programmable microstructure, customizable shapes, and tunable mechanical response including negative elastic modulus. However, in many applications the success of these 3D printed materials as a viable replacement for traditional stochastic foams critically depends on their mechanical performance and micro-architectural stability while deployed under long-term mechanical strain. To predict the long-term performance of the two types of foams we employed multi-year-long accelerated aging studies under compressive strain followed by a time-temperature-superposition analysis using a minimum-arc-length-based algorithm. The resulting master curves predict superior long-term performance of the 3D printed foam in terms of two different metrics, i.e., compression set and load retention. To gain deeper understanding, we imaged the microstructure of both foams using X-ray computed tomography, and performed finite-element analysis of the mechanical response within these microstructures. As a result, this indicates a wider stress variation in the stochastic foam with points of more extreme local stress as compared to the 3D printed material, which might explain the latter’s improved long-term stability and mechanical performance.

  4. 3D printed cellular solid outperforms traditional stochastic foam in long-term mechanical response

    PubMed Central

    Maiti, A.; Small, W.; Lewicki, J. P.; Weisgraber, T. H.; Duoss, E. B.; Chinn, S. C.; Pearson, M. A.; Spadaccini, C. M.; Maxwell, R. S.; Wilson, T. S.

    2016-01-01

    3D printing of polymeric foams by direct-ink-write is a recent technological breakthrough that enables the creation of versatile compressible solids with programmable microstructure, customizable shapes, and tunable mechanical response including negative elastic modulus. However, in many applications the success of these 3D printed materials as a viable replacement for traditional stochastic foams critically depends on their mechanical performance and micro-architectural stability while deployed under long-term mechanical strain. To predict the long-term performance of the two types of foams we employed multi-year-long accelerated aging studies under compressive strain followed by a time-temperature-superposition analysis using a minimum-arc-length-based algorithm. The resulting master curves predict superior long-term performance of the 3D printed foam in terms of two different metrics, i.e., compression set and load retention. To gain deeper understanding, we imaged the microstructure of both foams using X-ray computed tomography, and performed finite-element analysis of the mechanical response within these microstructures. This indicates a wider stress variation in the stochastic foam with points of more extreme local stress as compared to the 3D printed material, which might explain the latter’s improved long-term stability and mechanical performance. PMID:27117858

  5. Development of a 3D Graphene Electrode Dielectrophoretic Device

    PubMed Central

    Xie, Hongyu; Tewari, Radheshyam; Fukushima, Hiroyuki; Narendra, Jeffri; Heldt, Caryn; King, Julia; Minerick, Adrienne R.

    2014-01-01

    The design and fabrication of a novel 3D electrode microdevice using 50 µm thick graphene paper and 100 µm double sided tape is described. The protocol details the procedures to construct a versatile, reusable, multiple layer, laminated dielectrophoresis chamber. Specifically, six layers of 50 µm x 0.7 cm x 2 cm graphene paper and five layers of double sided tape were alternately stacked together, then clamped to a glass slide. Then a 700 μm diameter micro-well was drilled through the laminated structure using a computer-controlled micro drilling machine. Insulating properties of the tape layer between adjacent graphene layers were assured by resistance tests. Silver conductive epoxy connected alternate layers of graphene paper and formed stable connections between the graphene paper and external copper wire electrodes. The finished device was then clamped and sealed to a glass slide. The electric field gradient was modeled within the multi-layer device. Dielectrophoretic behaviors of 6 μm polystyrene beads were demonstrated in the 1 mm deep micro-well, with medium conductivities ranging from 0.0001 S/m to 1.3 S/m, and applied signal frequencies from 100 Hz to 10 MHz. Negative dielectrophoretic responses were observed in three dimensions over most of the conductivity-frequency space and cross-over frequency values are consistent with previously reported literature values. The device did not prevent AC electroosmosis and electrothermal flows, which occurred in the low and high frequency regions, respectively. The graphene paper utilized in this device is versatile and could subsequently function as a biosensor after dielectrophoretic characterizations are complete. PMID:24998694

  6. 3D Printing Variable Stiffness Foams Using Viscous Thread Instability

    PubMed Central

    Lipton, Jeffrey I.; Lipson, Hod

    2016-01-01

    Additive manufacturing of cellular structures has numerous applications ranging from fabrication of biological scaffolds and medical implants, to mechanical weight reduction and control over mechanical properties. Various additive manufacturing processes have been used to produce open regular cellular structures limited only by the resolution of the printer. These efforts have focused on printing explicitly designed cells or explicitly planning offsets between strands. Here we describe a technique for producing cellular structures implicitly by inducing viscous thread instability when extruding material. This process allows us to produce complex cellular structures at a scale that is finer than the native resolution of the printer. We demonstrate tunable effective elastic modulus and density that span two orders of magnitude. Fine grained cellular structures allow for fabrication of foams for use in a wide range of fields ranging from bioengineering, to robotics to food printing. PMID:27503148

  7. 3D Printing Variable Stiffness Foams Using Viscous Thread Instability.

    PubMed

    Lipton, Jeffrey I; Lipson, Hod

    2016-08-09

    Additive manufacturing of cellular structures has numerous applications ranging from fabrication of biological scaffolds and medical implants, to mechanical weight reduction and control over mechanical properties. Various additive manufacturing processes have been used to produce open regular cellular structures limited only by the resolution of the printer. These efforts have focused on printing explicitly designed cells or explicitly planning offsets between strands. Here we describe a technique for producing cellular structures implicitly by inducing viscous thread instability when extruding material. This process allows us to produce complex cellular structures at a scale that is finer than the native resolution of the printer. We demonstrate tunable effective elastic modulus and density that span two orders of magnitude. Fine grained cellular structures allow for fabrication of foams for use in a wide range of fields ranging from bioengineering, to robotics to food printing.

  8. 3D Printing Variable Stiffness Foams Using Viscous Thread Instability

    NASA Astrophysics Data System (ADS)

    Lipton, Jeffrey I.; Lipson, Hod

    2016-08-01

    Additive manufacturing of cellular structures has numerous applications ranging from fabrication of biological scaffolds and medical implants, to mechanical weight reduction and control over mechanical properties. Various additive manufacturing processes have been used to produce open regular cellular structures limited only by the resolution of the printer. These efforts have focused on printing explicitly designed cells or explicitly planning offsets between strands. Here we describe a technique for producing cellular structures implicitly by inducing viscous thread instability when extruding material. This process allows us to produce complex cellular structures at a scale that is finer than the native resolution of the printer. We demonstrate tunable effective elastic modulus and density that span two orders of magnitude. Fine grained cellular structures allow for fabrication of foams for use in a wide range of fields ranging from bioengineering, to robotics to food printing.

  9. Investigation of foam flow in a 3D printed porous medium in the presence of oil.

    PubMed

    Osei-Bonsu, Kofi; Grassia, Paul; Shokri, Nima

    2017-03-15

    Foams demonstrate great potential for displacing fluids in porous media which is applicable to a variety of subsurface operations such as the enhanced oil recovery and soil remediation. The application of foam in these processes is due to its unique ability to reduce gas mobility by increasing its effective viscosity and to divert gas to un-swept low permeability zones in porous media. The presence of oil in porous media is detrimental to the stability of foams which can influence its success as a displacing fluid. In the present work, we have conducted a systematic series of experiments using a well-characterised porous medium manufactured by 3D printing technique to evaluate the influence of oil on the dynamics of foam displacement under different boundary conditions. The effects of the type of oil, foam quality and foam flow rate were investigated. Our results reveal that generation of stable foam is delayed in the presence of light oil in the porous medium compared to heavy oil. Additionally, it was observed that the dynamics of oil entrapment was dictated by the stability of foam in the presence of oil. Furthermore, foams with high gas fraction appeared to be less stable in the presence of oil lowering its recovery efficiency. Pore-scale inspection of foam-oil dynamics during displacement revealed formation of a less stable front as the foam quality increased, leading to less oil recovery. This study extends the physical understanding of oil displacement by foam in porous media and provides new physical insights regarding the parameters influencing this process.

  10. Solar-thermal conversion and thermal energy storage of graphene foam-based composites

    NASA Astrophysics Data System (ADS)

    Zhang, Lianbin; Li, Renyuan; Tang, Bo; Wang, Peng

    2016-07-01

    Among various utilizations of solar energy, solar-thermal conversion has recently gained renewed research interest due to its extremely high energy efficiency. However, one limiting factor common to all solar-based energy conversion technologies is the intermittent nature of solar irradiation, which makes them unable to stand-alone to satisfy the continuous energy need. Herein, we report a three-dimensional (3D) graphene foam and phase change material (PCM) composite for the seamlessly combined solar-thermal conversion and thermal storage for sustained energy release. The composite is obtained by infiltrating the 3D graphene foam with a commonly used PCM, paraffin wax. The high macroporosity and low density of the graphene foam allow for high weight fraction of the PCM to be incorporated, which enhances the heat storage capacity of the composite. The interconnected graphene sheets in the composite provide (1) the solar-thermal conversion capability, (2) high thermal conductivity and (3) form stability of the composite. Under light irradiation, the composite effectively collects and converts the light energy into thermal energy, and the converted thermal energy is stored in the PCM and released in an elongated period of time for sustained utilization. This study provides a promising route for sustainable utilization of solar energy.Among various utilizations of solar energy, solar-thermal conversion has recently gained renewed research interest due to its extremely high energy efficiency. However, one limiting factor common to all solar-based energy conversion technologies is the intermittent nature of solar irradiation, which makes them unable to stand-alone to satisfy the continuous energy need. Herein, we report a three-dimensional (3D) graphene foam and phase change material (PCM) composite for the seamlessly combined solar-thermal conversion and thermal storage for sustained energy release. The composite is obtained by infiltrating the 3D graphene foam with a

  11. Experimental and Numerical Investigation of Forging Process to Reproduce a 3D Aluminium Foam Complex Shape

    SciTech Connect

    Filice, Luigino; Gagliardi, Francesco; Umbrello, Domenico; Shivpuri, Rajiv

    2007-05-17

    Metallic foams represent one of the most exciting materials introduced in the manufacturing scenario in the last years. In the study here addressed, the experimental and numerical investigations on the forging process of a simple foam billet shaped into complex sculptured parts were carried out. In particular, the deformation behavior of metallic foams and the development of density gradients were investigated through a series of experimental forging tests in order to produce a selected portion of a hip prosthesis. The human bone replacement was chosen as case study due to its industrial demand and for its particular 3D complex shape. A finite element code (Deform 3D) was utilized for modeling the foam behavior during the forging process and an accurate material rheology description was used based on a porous material model which includes the measured local density. Once the effectiveness of the utilized Finite Element model was verified through the comparison with the experimental evidences, a numerical study of the influence of the foam density was investigated. The obtained numerical results shown as the initial billet density plays an important role on the prediction of the final shape, the optimization of the flash as well as the estimation of the punch load.

  12. Three-dimensional graphene foam as a biocompatible and conductive scaffold for neural stem cells

    PubMed Central

    Li, Ning; Zhang, Qi; Gao, Song; Song, Qin; Huang, Rong; Wang, Long; Liu, Liwei; Dai, Jianwu; Tang, Mingliang; Cheng, Guosheng

    2013-01-01

    Neural stem cell (NSC) based therapy provides a promising approach for neural regeneration. For the success of NSC clinical application, a scaffold is required to provide three-dimensional (3D) cell growth microenvironments and appropriate synergistic cell guidance cues. Here, we report the first utilization of graphene foam, a 3D porous structure, as a novel scaffold for NSCs in vitro. It was found that three-dimensional graphene foams (3D-GFs) can not only support NSC growth, but also keep cell at an active proliferation state with upregulation of Ki67 expression than that of two-dimensional graphene films. Meanwhile, phenotypic analysis indicated that 3D-GFs can enhance the NSC differentiation towards astrocytes and especially neurons. Furthermore, a good electrical coupling of 3D-GFs with differentiated NSCs for efficient electrical stimulation was observed. Our findings implicate 3D-GFs could offer a powerful platform for NSC research, neural tissue engineering and neural prostheses. PMID:23549373

  13. Controllable growth of polyaniline nanowire arrays on hierarchical macro/mesoporous graphene foams for high-performance flexible supercapacitors

    NASA Astrophysics Data System (ADS)

    Yu, Pingping; Zhao, Xin; Li, Yingzhi; Zhang, Qinghua

    2017-01-01

    Free-standing hierarchical macro/mesoporous flexible graphene foam have been constructed by rational intergration ofwell dispersed graphene oxide sheets and amino-modified polystyrene (PS) spheres through a facile "templating and embossing" technique. The three dimensional (3D) macro/mesoporous flexible graphene foam not only inherits the uniform porous structures of graphene foam, but also contains hierarchical macro/mesopores on the struts by sacrificing PS spheres and the activation of KOH, which could providing rapid pathways for ionic and electronic transport to high specific capacitance. Vertically polyaniline (PANI) nanowire arrays are then uniformly deposited onto the hierarchical macro/mesoporous graphene foam(fRGO-F/PANI) by a simple in situ polymerization, which show a high specific capacitance of 939 F g-1. Thanks to the synergistic function of 3D bicontinuous hierarchical porous structure of graphene foam and effective immobilization of PANI nanowires on the struts, the assembled symmetric supercapctior with fRGO-F/PANI as electrodes exhibits a maximum energy density and power density of 20.9 Wh kg-1 and 103.2 kW kg-1, respectively. Moreover, it also displays an excellent cyclic stability with a 88.7% retention after 5000 cycles.

  14. A facile synthesis of graphene foam as electrode material for supercapacitor

    NASA Astrophysics Data System (ADS)

    Sivaprakash, S.; Sivaprakash, Prabhavathy

    2016-07-01

    We report here a versatile fabrication approach of graphene foam (GF) with three dimensional (3D) porous conductive networks which reveal great potential for application in energy storage devices. This facile fabrication technique is believed to be favorable for supercapacitor application as the 3D-GF comprises conductive continuous porous networks with large active surface area. Supercapacitors utilize this high surface area electrode to attain improved capacitance. The resulting graphene foam exhibited satisfactory double layer capacitive behavior with improved electrochemical performance having good electrochemical cycling stability and high specific capacitance of 310 F g-1 at current density of 5 A g-1 and 160 F g-1 at current density of 20 A g-1.

  15. Solar-thermal conversion and thermal energy storage of graphene foam-based composites.

    PubMed

    Zhang, Lianbin; Li, Renyuan; Tang, Bo; Wang, Peng

    2016-08-14

    Among various utilizations of solar energy, solar-thermal conversion has recently gained renewed research interest due to its extremely high energy efficiency. However, one limiting factor common to all solar-based energy conversion technologies is the intermittent nature of solar irradiation, which makes them unable to stand-alone to satisfy the continuous energy need. Herein, we report a three-dimensional (3D) graphene foam and phase change material (PCM) composite for the seamlessly combined solar-thermal conversion and thermal storage for sustained energy release. The composite is obtained by infiltrating the 3D graphene foam with a commonly used PCM, paraffin wax. The high macroporosity and low density of the graphene foam allow for high weight fraction of the PCM to be incorporated, which enhances the heat storage capacity of the composite. The interconnected graphene sheets in the composite provide (1) the solar-thermal conversion capability, (2) high thermal conductivity and (3) form stability of the composite. Under light irradiation, the composite effectively collects and converts the light energy into thermal energy, and the converted thermal energy is stored in the PCM and released in an elongated period of time for sustained utilization. This study provides a promising route for sustainable utilization of solar energy.

  16. Experimental and Numerical Investigation of Forging Process to Reproduce a 3D Aluminium Foam Complex Shape

    NASA Astrophysics Data System (ADS)

    Filice, Luigino; Gagliardi, Francesco; Shivpuri, Rajiv; Umbrello, Domenico

    2007-05-01

    Metallic foams represent one of the most exciting materials introduced in the manufacturing scenario in the last years. In the study here addressed, the experimental and numerical investigations on the forging process of a simple foam billet shaped into complex sculptured parts were carried out. In particular, the deformation behavior of metallic foams and the development of density gradients were investigated through a series of experimental forging tests in order to produce a selected portion of a hip prosthesis. The human bone replacement was chosen as case study due to its industrial demand and for its particular 3D complex shape. A finite element code (Deform 3D®) was utilized for modeling the foam behavior during the forging process and an accurate material rheology description was used based on a porous material model which includes the measured local density. Once the effectiveness of the utilized Finite Element model was verified through the comparison with the experimental evidences, a numerical study of the influence of the foam density was investigated. The obtained numerical results shown as the initial billet density plays an important role on the prediction of the final shape, the optimization of the flash as well as the estimation of the punch load.

  17. Flexible and Thermostable Graphene/SiC Nanowire Foam Composites with Tunable Electromagnetic Wave Absorption Properties.

    PubMed

    Han, Meikang; Yin, Xiaowei; Hou, Zexin; Song, Changqing; Li, Xinliang; Zhang, Litong; Cheng, Laifei

    2017-04-05

    Three-dimensional (3D) flexible foams consisting of reduced graphene oxides (rGO) and in situ grown SiC nanowires (NWs) were prepared using freeze-drying and carbothermal reduction processes. By means of incorporating SiC nanowires into rGO foams, both the thermostability and electromagnetic absorption of the composites were improved. It was demonstrated that rGO/SiC NW foams were thermostable beyond ∼630 °C (90% weight retention in air atmosphere). As expected, rGO/SiC NW foams in the poly(dimethylsiloxane) matrix achieved effective absorption in the entire X-band (8.2-12.4 GHz) with a thinner thickness (3 mm) in comparison with those of the pure rGO foams. It is revealed that SiC nanowires with abundant stacking faults, twinning interfaces, and bridged junctions play an important role in the enhanced electromagnetic absorption performance, in addition to the contribution of interconnected graphene networks. Hierarchical rGO/SiC NW foams not only are efficient absorbers in the critical environments but also can be applied in photocatalytic and thermal-management fields.

  18. Self-assembly and embedding of nanoparticles by in situ reduced graphene for preparation of a 3D graphene/nanoparticle aerogel.

    PubMed

    Chen, Wufeng; Li, Sirong; Chen, Chunhua; Yan, Lifeng

    2011-12-15

    A 3D graphene architecture can be prepared via an in situ self-assembly of graphene prepared by a mild chemical reduction. Fe(3) O(4) nanoparticles are homogeneously dispersed into graphene oxide (GO) aqueous suspension and a 3D magnetic graphene/Fe(3) O(4) aerogel is prepared during the reduction of GO to graphene. This provides a general method to prepare 3D graphene/nanoparticle composites for a wide range of applications including catalysis and energy conversion.

  19. Laser induced white lighting of graphene foam

    NASA Astrophysics Data System (ADS)

    Strek, Wieslaw; Tomala, Robert; Lukaszewicz, Mikolaj; Cichy, Bartlomiej; Gerasymchuk, Yuriy; Gluchowski, Pawel; Marciniak, Lukasz; Bednarkiewicz, Artur; Hreniak, Dariusz

    2017-01-01

    Laser induced white light emission was observed from porous graphene foam irradiated with a focused continuous wave beam of the infrared laser diode. It was found that the intensity of the emission increases exponentially with increasing laser power density, having a saturation level at ca. 1.5 W and being characterized by stable emission conditions. It was also observed that the white light emission is spatially confined to the focal point dimensions of the illuminating laser light. Several other features of the laser induced white light emission were also discussed. It was observed that the white light emission is highly dependent on the electric field intensity, allowing one to modulate the emission intensity. The electric field intensity ca. 0.5 V/μm was able to decrease the white light intensity by half. Origins of the laser-induced white light emission along with its characteristic features were discussed in terms of avalanche multiphoton ionization, inter-valence charge transfer and possible plasma build-up processes. It is shown that the laser-induced white light emission may be well utilized in new types of white light sources.

  20. Laser induced white lighting of graphene foam

    PubMed Central

    Strek, Wieslaw; Tomala, Robert; Lukaszewicz, Mikolaj; Cichy, Bartlomiej; Gerasymchuk, Yuriy; Gluchowski, Pawel; Marciniak, Lukasz; Bednarkiewicz, Artur; Hreniak, Dariusz

    2017-01-01

    Laser induced white light emission was observed from porous graphene foam irradiated with a focused continuous wave beam of the infrared laser diode. It was found that the intensity of the emission increases exponentially with increasing laser power density, having a saturation level at ca. 1.5 W and being characterized by stable emission conditions. It was also observed that the white light emission is spatially confined to the focal point dimensions of the illuminating laser light. Several other features of the laser induced white light emission were also discussed. It was observed that the white light emission is highly dependent on the electric field intensity, allowing one to modulate the emission intensity. The electric field intensity ca. 0.5 V/μm was able to decrease the white light intensity by half. Origins of the laser-induced white light emission along with its characteristic features were discussed in terms of avalanche multiphoton ionization, inter-valence charge transfer and possible plasma build-up processes. It is shown that the laser-induced white light emission may be well utilized in new types of white light sources. PMID:28112254

  1. 3D Oxidized Graphene Frameworks for Efficient Nano Sieving

    NASA Astrophysics Data System (ADS)

    Pawar, Pranav Bhagwan; Saxena, Sumit; Badhe, Dhanashree Kamlesh; Chaudhary, Raghvendra Pratap; Shukla, Shobha

    2016-02-01

    The small size of Na+ and Cl‑ ions provides a bottleneck in desalination and is a challenge in providing alternatives for continuously depleting fresh water resources. Graphene by virtue of its structural properties has the potential to address this issue. Studies have indicated that use of monolayer graphene can be used to filter micro volumes of saline solution. Unfortunately it is extremely difficult, resource intensive and almost impractical with current technology to fabricate operational devices using mono-layered graphene. Nevertheless, graphene based devices still hold the key to solve this problem due to its nano-sieving ability. Here we report synthesis of oxidized graphene frameworks and demonstrate a functional device to desalinate and purify seawater from contaminants including Na+ and Cl‑ ions, dyes and other microbial pollutants. Micro-channels in these frameworks help in immobilizing larger suspended solids including bacteria, while nano-sieving through graphene enables the removal of dissolved ions (e.g. Cl‑). Nano-sieving incorporated with larger frameworks has been used in filtering Na+ and Cl‑ ions in functional devices.

  2. 3D Oxidized Graphene Frameworks for Efficient Nano Sieving

    PubMed Central

    Pawar, Pranav Bhagwan; Saxena, Sumit; Badhe, Dhanashree Kamlesh; Chaudhary, Raghvendra Pratap; Shukla, Shobha

    2016-01-01

    The small size of Na+ and Cl− ions provides a bottleneck in desalination and is a challenge in providing alternatives for continuously depleting fresh water resources. Graphene by virtue of its structural properties has the potential to address this issue. Studies have indicated that use of monolayer graphene can be used to filter micro volumes of saline solution. Unfortunately it is extremely difficult, resource intensive and almost impractical with current technology to fabricate operational devices using mono-layered graphene. Nevertheless, graphene based devices still hold the key to solve this problem due to its nano-sieving ability. Here we report synthesis of oxidized graphene frameworks and demonstrate a functional device to desalinate and purify seawater from contaminants including Na+ and Cl− ions, dyes and other microbial pollutants. Micro-channels in these frameworks help in immobilizing larger suspended solids including bacteria, while nano-sieving through graphene enables the removal of dissolved ions (e.g. Cl−). Nano-sieving incorporated with larger frameworks has been used in filtering Na+ and Cl− ions in functional devices. PMID:26892277

  3. Novel Synthesis of 3D Graphene-CNF Electrode Architectures for Supercapacitor Applications

    DTIC Science & Technology

    2013-06-01

    NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA THESIS Approved for public release; distribution is unlimited NOVEL SYNTHESIS OF...AND DATES COVERED Master’s Thesis 4. TITLE AND SUBTITLE NOVEL SYNTHESIS OF 3D GRAPHENE-CNF ELECTRODE ARCHITECTURES FOR SUPERCAPACITOR...Carbon Nanofibers (CNF). The Reduction Expansion Synthesis (RES) approach was used for both, the exfoliation of Graphitic Oxide to produce Graphene

  4. Preparation of Tunable 3D Pillared Carbon Nanotube-Graphene Networks for High-Performance Capacitance

    DTIC Science & Technology

    2011-01-01

    puter modeling has predicted that such a 3D pillared VACNT graphene structure can be used for efficient hydrogen storage after being doped with...Pillared Carbon Nanotube Graphene Networks for High-Performance Capacitance Feng Du,†,§ Dingshan Yu,†,§ Liming Dai,†,* S. Ganguli,‡ V. Varshney,‡ and A...nanotubes (CNTs) and two-dimensional (2D) single-atomic layer graphene , have been demonstrated to show superior thermal, electrical, and mechanical

  5. Synthesis, properties and applications of 3D carbon nanotube-graphene junctions

    NASA Astrophysics Data System (ADS)

    Lin, Chun-Yu; Zhao, Zhenghang; Niu, Jianbing; Xia, Zhenhai

    2016-11-01

    Integration of 1D carbon nanotubes and 2D graphene sheets through covalent bonding can create novel 3D nanoporous hybrid nanostructures that inherit unique mechanical, thermal, electrical and chemical properties of their building blocks and even have new properties in three dimensions. Great progress has been made in developing 3D carbon nanotube-graphene nanoarchitectures for various applications such as mechanical cushions, thermal sinkers, transistors, and renewable energy conversion. This review presents the recent advances in synthesis and analysis of the 3D nanostructures. Emphasis is put on design principles, molecular structures, processes and properties of the materials.

  6. Incommensurate Graphene Foam as a High Capacity Lithium Intercalation Anode

    NASA Astrophysics Data System (ADS)

    Paronyan, Tereza M.; Thapa, Arjun Kumar; Sherehiy, Andriy; Jasinski, Jacek B.; Jangam, John Samuel Dilip

    2017-01-01

    Graphite’s capacity of intercalating lithium in rechargeable batteries is limited (theoretically, 372 mAh g‑1) due to low diffusion within commensurately-stacked graphene layers. Graphene foam with highly enriched incommensurately-stacked layers was grown and applied as an active electrode in rechargeable batteries. A 93% incommensurate graphene foam demonstrated a reversible specific capacity of 1,540 mAh g‑1 with a 75% coulombic efficiency, and an 86% incommensurate sample achieves above 99% coulombic efficiency exhibiting 930 mAh g‑1 specific capacity. The structural and binding analysis of graphene show that lithium atoms highly intercalate within weakly interacting incommensurately-stacked graphene network, followed by a further flexible rearrangement of layers for a long-term stable cycling. We consider lithium intercalation model for multilayer graphene where capacity varies with N number of layers resulting LiN+1C2N stoichiometry. The effective capacity of commonly used carbon-based rechargeable batteries can be significantly improved using incommensurate graphene as an anode material.

  7. Incommensurate Graphene Foam as a High Capacity Lithium Intercalation Anode

    PubMed Central

    Paronyan, Tereza M.; Thapa, Arjun Kumar; Sherehiy, Andriy; Jasinski, Jacek B.; Jangam, John Samuel Dilip

    2017-01-01

    Graphite’s capacity of intercalating lithium in rechargeable batteries is limited (theoretically, 372 mAh g−1) due to low diffusion within commensurately-stacked graphene layers. Graphene foam with highly enriched incommensurately-stacked layers was grown and applied as an active electrode in rechargeable batteries. A 93% incommensurate graphene foam demonstrated a reversible specific capacity of 1,540 mAh g−1 with a 75% coulombic efficiency, and an 86% incommensurate sample achieves above 99% coulombic efficiency exhibiting 930 mAh g−1 specific capacity. The structural and binding analysis of graphene show that lithium atoms highly intercalate within weakly interacting incommensurately-stacked graphene network, followed by a further flexible rearrangement of layers for a long-term stable cycling. We consider lithium intercalation model for multilayer graphene where capacity varies with N number of layers resulting LiN+1C2N stoichiometry. The effective capacity of commonly used carbon-based rechargeable batteries can be significantly improved using incommensurate graphene as an anode material. PMID:28059110

  8. Powder, paper and foam of few-layer graphene prepared in high yield by electrochemical intercalation exfoliation of expanded graphite.

    PubMed

    Wu, Liqiong; Li, Weiwei; Li, Peng; Liao, Shutian; Qiu, Shengqiang; Chen, Mingliang; Guo, Yufen; Li, Qi; Zhu, Chao; Liu, Liwei

    2014-04-09

    A facile and high-yield approach to the preparation of few-layer graphene (FLG) by electrochemical intercalation exfoliation (EIE) of expanded graphite in sulfuric acid electrolyte is reported. Stage-1 H2SO4-graphite intercalation compound is used as a key intermediate in EIE to realize the efficient exfoliation. The yield of the FLG sheets (<7 layers) with large lateral sizes (tens of microns) is more than 75% relative to the total amount of starting expanded graphite. A low degree of oxygen functionalization existing in the prepared FLG flakes enables them to disperse effectively, which contributes to the film-forming characteristics of the FLG flakes. These electrochemically exfoliated FLG flakes are integrated into several kinds of macroscopic graphene structures. Flexible and freestanding graphene papers made of the FLG flakes retain excellent conductivity (≈24,500 S m(-1)). Three-dimensional (3D) graphene foams with light weight are fabricated from the FLG flakes by the use of Ni foams as self-sacrifice templates. Furthermore, 3D graphene/Ni foams without any binders, which are used as supercapacitor electrodes in aqueous electrolyte, provide the specific capacitance of 113.2 F g(-1) at a current density of 0.5 A g(-1), retaining 90% capacitance after 1000 cycles.

  9. Recent advance in fabricating monolithic 3D porous graphene and their applications in biosensing and biofuel cells.

    PubMed

    Qiu, Hua-Jun; Guan, Yongxin; Luo, Pan; Wang, Yu

    2017-03-15

    Graphene shows great potential in biosensing and bioelectronics. To facilitate graphene's applications and enhance its performance, recently, three-dimensional (3D) graphene-based materials especially free-standing porous graphene with tunable pore size and void space, have attracted increasing attention for bio-related applications owing to their special features. 3D graphene usually shows the following merits such as an interconnected porous network, a high electronic conductivity, a large active surface area, good chemical/thermal stability and can be more easily handled compared with dispersed graphene sheets. With modified surface properties, graphene can also be bio-friendly. These properties make 3D graphene a perfect candidate as high-performance electrode materials in bioelectronics devices. In this review, we discuss recent advance in fabricating monolithic 3D graphene and their applications in biosensing and biofuel cells.

  10. Stacked 3D RRAM Array with Graphene/CNT as Edge Electrodes

    PubMed Central

    Bai, Yue; Wu, Huaqiang; Wang, Kun; Wu, Riga; Song, Lin; Li, Tianyi; Wang, Jiangtao; Yu, Zhiping; Qian, He

    2015-01-01

    There are two critical challenges which determine the array density of 3D RRAM: 1) the scaling limit in both horizontal and vertical directions; 2) the integration of selector devices in 3D structure. In this work, we present a novel 3D RRAM structure using low-dimensional materials, including 2D graphene and 1D carbon nanotube (CNT), as the edge electrodes. A two-layer 3D RRAM with monolayer graphene as edge electrode is demonstrated. The electrical results reveal that the RRAM devices could switch normally with this very thin edge electrode at nanometer scale. Meanwhile, benefited from the asymmetric carrier transport induced by Schottky barrier at metal/CNT and oxide/CNT interfaces, a selector built-in 3D RRAM structure using CNT as edge electrode is successfully fabricated and characterized. Furthermore, the discussion of high array density potential is presented. PMID:26348797

  11. Stacked 3D RRAM Array with Graphene/CNT as Edge Electrodes.

    PubMed

    Bai, Yue; Wu, Huaqiang; Wang, Kun; Wu, Riga; Song, Lin; Li, Tianyi; Wang, Jiangtao; Yu, Zhiping; Qian, He

    2015-09-08

    There are two critical challenges which determine the array density of 3D RRAM: 1) the scaling limit in both horizontal and vertical directions; 2) the integration of selector devices in 3D structure. In this work, we present a novel 3D RRAM structure using low-dimensional materials, including 2D graphene and 1D carbon nanotube (CNT), as the edge electrodes. A two-layer 3D RRAM with monolayer graphene as edge electrode is demonstrated. The electrical results reveal that the RRAM devices could switch normally with this very thin edge electrode at nanometer scale. Meanwhile, benefited from the asymmetric carrier transport induced by Schottky barrier at metal/CNT and oxide/CNT interfaces, a selector built-in 3D RRAM structure using CNT as edge electrode is successfully fabricated and characterized. Furthermore, the discussion of high array density potential is presented.

  12. 2D and 3D graphene materials: Preparation and bioelectrochemical applications.

    PubMed

    Gao, Hongcai; Duan, Hongwei

    2015-03-15

    The attractive properties of graphene materials have stimulated intense research and development in the field of bioelectrochemistry. In particular, the construction of 2D and 3D graphene architectures provides new possibilities for developing flexible and porous carbon scaffolds, which not only inherit some of the key properties of individual graphene sheets, but also develop additional functions that are of considerable interest for bioelectrochemical applications. In this review article, we will first summarize the recently developed approaches to preparing graphene sheets, and then focus on the methods to assemble them into macroscopic 2D and 3D structures. Furthermore, we will highlight the potential applications of these materials in electrochemical biosensors and biological fuel cells.

  13. PolyHIPE Derived Freestanding 3D Carbon Foam for Cobalt Hydroxide Nanorods Based High Performance Supercapacitor

    NASA Astrophysics Data System (ADS)

    Patil, Umakant M.; Ghorpade, Ravindra V.; Nam, Min Sik; Nalawade, Archana C.; Lee, Sangrae; Han, Haksoo; Jun, Seong Chan

    2016-10-01

    The current paper describes enhanced electrochemical capacitive performance of chemically grown Cobalt hydroxide (Co(OH)2) nanorods (NRs) decorated porous three dimensional graphitic carbon foam (Co(OH)2/3D GCF) as a supercapacitor electrode. Freestanding 3D porous GCF is prepared by carbonizing, high internal phase emulsion (HIPE) polymerized styrene and divinylbenzene. The PolyHIPE was sulfonated and carbonized at temperature up to 850 °C to obtain graphitic 3D carbon foam with high surface area (389 m2 g‑1) having open voids (14 μm) interconnected by windows (4 μm) in monolithic form. Moreover, entangled Co(OH)2 NRs are anchored on 3D GCF electrodes by using a facile chemical bath deposition (CBD) method. The wide porous structure with high specific surface area (520 m2 g‑1) access offered by the interconnected 3D GCF along with Co(OH)2 NRs morphology, displays ultrahigh specific capacitance, specific energy and power. The Co(OH)2/3D GCF electrode exhibits maximum specific capacitance about ~1235 F g‑1 at ~1 A g‑1 charge-discharge current density, in 1 M aqueous KOH solution. These results endorse potential applicability of Co(OH)2/3D GCF electrode in supercapacitors and signifies that, the porous GCF is a proficient 3D freestanding framework for loading pseudocapacitive nanostructured materials.

  14. PolyHIPE Derived Freestanding 3D Carbon Foam for Cobalt Hydroxide Nanorods Based High Performance Supercapacitor

    PubMed Central

    Patil, Umakant M.; Ghorpade, Ravindra V.; Nam, Min Sik; Nalawade, Archana C.; Lee, Sangrae; Han, Haksoo; Jun, Seong Chan

    2016-01-01

    The current paper describes enhanced electrochemical capacitive performance of chemically grown Cobalt hydroxide (Co(OH)2) nanorods (NRs) decorated porous three dimensional graphitic carbon foam (Co(OH)2/3D GCF) as a supercapacitor electrode. Freestanding 3D porous GCF is prepared by carbonizing, high internal phase emulsion (HIPE) polymerized styrene and divinylbenzene. The PolyHIPE was sulfonated and carbonized at temperature up to 850 °C to obtain graphitic 3D carbon foam with high surface area (389 m2 g−1) having open voids (14 μm) interconnected by windows (4 μm) in monolithic form. Moreover, entangled Co(OH)2 NRs are anchored on 3D GCF electrodes by using a facile chemical bath deposition (CBD) method. The wide porous structure with high specific surface area (520 m2 g−1) access offered by the interconnected 3D GCF along with Co(OH)2 NRs morphology, displays ultrahigh specific capacitance, specific energy and power. The Co(OH)2/3D GCF electrode exhibits maximum specific capacitance about ~1235 F g−1 at ~1 A g−1 charge-discharge current density, in 1 M aqueous KOH solution. These results endorse potential applicability of Co(OH)2/3D GCF electrode in supercapacitors and signifies that, the porous GCF is a proficient 3D freestanding framework for loading pseudocapacitive nanostructured materials. PMID:27762284

  15. Interfacing graphene and related 2D materials with the 3D world.

    PubMed

    Tománek, David

    2015-04-10

    An important prerequisite to translating the exceptional intrinsic performance of 2D materials such as graphene and transition metal dichalcogenides into useful devices precludes their successful integration within the current 3D technology. This review provides theoretical insight into nontrivial issues arising from interfacing 2D materials with 3D systems including epitaxy and ways to accommodate lattice mismatch, the key role of contact resistance and the effect of defects in electrical and thermal transport.

  16. Graphene Oxide-Based Electrode Inks for 3D-Printed Lithium-Ion Batteries.

    PubMed

    Fu, Kun; Wang, Yibo; Yan, Chaoyi; Yao, Yonggang; Chen, Yanan; Dai, Jiaqi; Lacey, Steven; Wang, Yanbin; Wan, Jiayu; Li, Tian; Wang, Zhengyang; Xu, Yue; Hu, Liangbing

    2016-04-06

    All-component 3D-printed lithium-ion batteries are fabricated by printing graphene-oxide-based composite inks and solid-state gel polymer electrolyte. An entirely 3D-printed full cell features a high electrode mass loading of 18 mg cm(-2) , which is normalized to the overall area of the battery. This all-component printing can be extended to the fabrication of multidimensional/multiscale complex-structures of more energy-storage devices.

  17. Polydopamine decorated 3D nickel foam for extraction of sixteen polycyclic aromatic hydrocarbons.

    PubMed

    Cai, Ying; Yan, Zhihong; Yang, Ming; Huang, Xiaoying; Min, Weiping; Wang, Lijia; Cai, Qingyun

    2016-12-23

    In this work, polydopamine coated 3D nickel foam (NF-PDA) was prepared and applied as sorbent for the solid phase extraction (SPE) of 16 polycyclic aromatic hydrocarbons (PAHs) from water samples. NF-PDA were synthesized by situ oxidative self-polymerization procedure and characterized by using the techniques of scanning electron microscopy (SEM), energy dispersive spectrum analysis (EDS) and X-ray photoelectron spectroscopy (XPS). Its performance was evaluated by the SPE of 16 PAHs from water samples, followed by gas chromatography-mass spectrometrical (GC-MS) analysis. The effects of the main experimental parameters (i.e. sorbent amount, desorption solvent, extraction time, water sample volume, elution volume, elution time, ionic strength and samle solution pH.) that could affect the extraction efficiencies were investigated. The results demonstrated that the NF-PDA had an excellent adsorption capability for the compounds. The methodology was validated for river water and wastewater, obtaining recoveries ranging from 89.6 to 97.5% with relative standard deviation values lower than 7.3% and limits of detection in the range 2.3-16.5ng/L.

  18. 3D hydrogel scaffold doped with 2D graphene materials for biosensors and bioelectronics.

    PubMed

    Song, Hyun Seok; Kwon, Oh Seok; Kim, Jae-Hong; Conde, João; Artzi, Natalie

    2017-03-15

    Hydrogels consisting of three-dimensional (3D) polymeric networks have found a wide range of applications in biotechnology due to their large water capacity, high biocompatibility, and facile functional versatility. The hydrogels with stimulus-responsive swelling properties have been particularly instrumental to realizing signal transduction in biosensors and bioelectronics. Graphenes are two-dimensional (2D) nanomaterials with unprecedented physical, optical, and electronic properties and have also found many applications in biosensors and bioelectronics. These two classes of materials present complementary strengths and limitations which, when effectively coupled, can result in significant synergism in their electrical, mechanical, and biocompatible properties. This report reviews recent advances made with hydrogel and graphene materials for the development of high-performance bioelectronics devices. The report focuses on the interesting intersection of these materials wherein 2D graphenes are hybridized with 3D hydrogels to develop the next generation biosensors and bioelectronics.

  19. Wet chemical method for synthesizing 3D graphene/gold nanocomposite: catalytic reduction of methylene blue

    NASA Astrophysics Data System (ADS)

    Xie, Jiliang; Yang, Xujie; Xu, Xingyou

    2017-04-01

    In this paper, a simple and environmentally-friendly approach was reported to synthesize a novel 3D composite of graphene/gold nanoparticles (3DG/Au NPs) in one step. A 3D interlaced framework of graphene, which exhibited hierarchically porous structures, generated directly through the distinct driving force during the hydrothermal growth. Meanwhile, Au NPs with high dispersity, which displayed tunable morphologies, were immobilized on the framework, where the as-prepared graphene was employed as the endogenous reducing agent. Compared with AuNPs, the obtained 3DG/Au NPs exhibited remarkably convenient recyclability and high activity for the reduction of methylene blue which is a kind of organic dye.

  20. Dynamic stress-strain states for metal foams using a 3D cellular model

    NASA Astrophysics Data System (ADS)

    Zheng, Zhijun; Wang, Changfeng; Yu, Jilin; Reid, Stephen R.; Harrigan, John J.

    2014-12-01

    Dynamic uniaxial impact behaviour of metal foams using a 3D cell-based finite element model is examined. At sufficiently high loading rates, these materials respond by forming ‘shock or consolidation waves' (Tan et al., 2005a, 2005b). However, the existing dynamic experimental methods have limitations in fully informing this behaviour, particularly for solving boundary/initial value problems. Recently, the problem of the shock-like response of an open-cell foam has been examined by Barnes et al. (2014) using the Hugoniot-curve representations. The present study is somewhat complementary to that approach and additionally aims to provide insight into the ‘rate sensitivity' mechanism applicable to cellular materials. To assist our understanding of the ‘loading rate sensitivity' behaviour of cellular materials, a virtual ‘test' method based on the direct impact technique is explored. Following a continuum representation of the response, the strain field calculation method is employed to determine the local strains ahead of and behind the resulting ‘shock front'. The dynamic stress-strain states in the densification stage are found to be different from the quasi-static ones. It is evident that the constitutive behaviour of the cellular material is deformation-mode dependent. The nature of the ‘rate sensitivity' revealed for cellular materials in this paper is different from the strain-rate sensitivity of dense metals. It is shown that the dynamic stress-strain states behind a shock front of the cellular material lie on a unique curve and each point on the curve corresponds to a particular ‘impact velocity', referred as the velocity upstream of the shock in this study. The dynamic stress-strain curve is related to a layer-wise collapse mode, whilst the equivalent quasi-static curve is related to a random shear band collapse mode. The findings herein are aimed at improving the experimental test techniques used to characterise the rate-sensitivity behaviour

  1. Porous Structures in Stacked, Crumpled and Pillared Graphene-Based 3D Materials

    PubMed Central

    Guo, Fei; Creighton, Megan; Chen, Yantao; Hurt, Robert; Külaots, Indrek

    2015-01-01

    Graphene, an atomically thin material with the theoretical surface area of 2600 m2g−1, has great potential in the fields of catalysis, separation, and gas storage if properly assembled into functional 3D materials at large scale. In ideal non-interacting ensembles of non-porous multilayer graphene plates, the surface area can be adequately estimated using the simple geometric law ~ 2600 m2g−1/N, where N is the number of graphene sheets per plate. Some processing operations, however, lead to secondary plate-plate stacking, folding, crumpling or pillaring, which give rise to more complex structures. Here we show that bulk samples of multilayer graphene plates stack in an irregular fashion that preserves the 2600/N surface area and creates regular slot-like pores with sizes that are multiples of the unit plate thickness. In contrast, graphene oxide deposits into films with massive area loss (2600 to 40 m2g−1) due to nearly perfect alignment and stacking during the drying process. Pillaring graphene oxide sheets by co-deposition of colloidal-phase particle-based spacers has the potential to partially restore the large monolayer surface. Surface areas as high as 1000 m2g−1 are demonstrated here through colloidal-phase deposition of graphene oxide with water-dispersible aryl-sulfonated ultrafine carbon black as a pillaring agent. PMID:26478597

  2. Superior lithium storage in a 3D macroporous graphene framework/SnO2 nanocomposite

    NASA Astrophysics Data System (ADS)

    Liu, Xiaowu; Cheng, Jianxiu; Li, Weihan; Zhong, Xiongwu; Yang, Zhenzhong; Gu, Lin; Yu, Yan

    2014-06-01

    A three-dimensional (3D) interconnected graphene framework (GF)-based SnO2 nanocomposite (3D SnO2/GFs) was prepared using self-assembly of polystyrene (PS)@SnO2 nanospheres and graphene oxide (GO) nanosheets under suitable pH conditions, followed by a thermal treatment. The electroactive material (SnO2) is anchored to the wall of electrochemically and ionically conductive 3D interconnected GFs. When used as anodes for LIBs, the 3D SnO2/GFs deliver an excellent reversible capacity (1244 mA h g-1 in 50 cycles at 100 mA g-1) and outstanding rate capability (754 mA h g-1 in 200 cycles at 1000 mA g-1). The ultra-small size of SnO2 (sub 10 nm) and dimensional confinement of SnO2 nanoparticles by the wall of GFs limit the volume expansion upon lithium insertion, and the 3D interconnected porous structures serve as buffered spaces during charge-discharge and result in superior electrochemical performance by facilitating the electrolyte to contact the entire nanocomposite materials and reduce lithium diffusion length in the nanocomposite.A three-dimensional (3D) interconnected graphene framework (GF)-based SnO2 nanocomposite (3D SnO2/GFs) was prepared using self-assembly of polystyrene (PS)@SnO2 nanospheres and graphene oxide (GO) nanosheets under suitable pH conditions, followed by a thermal treatment. The electroactive material (SnO2) is anchored to the wall of electrochemically and ionically conductive 3D interconnected GFs. When used as anodes for LIBs, the 3D SnO2/GFs deliver an excellent reversible capacity (1244 mA h g-1 in 50 cycles at 100 mA g-1) and outstanding rate capability (754 mA h g-1 in 200 cycles at 1000 mA g-1). The ultra-small size of SnO2 (sub 10 nm) and dimensional confinement of SnO2 nanoparticles by the wall of GFs limit the volume expansion upon lithium insertion, and the 3D interconnected porous structures serve as buffered spaces during charge-discharge and result in superior electrochemical performance by facilitating the electrolyte to contact

  3. Facile synthesis 3D flexible core-shell graphene/glass fiber via chemical vapor deposition

    PubMed Central

    2014-01-01

    Direct deposition of graphene layers on the flexible glass fiber surface to form the three-dimensional (3D) core-shell structures is offered using a two-heating reactor chemical vapor deposition system. The two-heating reactor is utilized to offer sufficient, well-proportioned floating C atoms and provide a facile way for low-temperature deposition. Graphene layers, which are controlled by changing the growth time, can be grown on the surface of wire-type glass fiber with the diameter from 30 nm to 120 um. The core-shell graphene/glass fiber deposition mechanism is proposed, suggesting that the 3D graphene films can be deposited on any proper wire-type substrates. These results open a facile way for direct and high-efficiency deposition of the transfer-free graphene layers on the low-temperature dielectric wire-type substrates. PACS 81.05.U-; 81.07.-b; 81.15.Gh PMID:25170331

  4. 3D scaffold alters cellular response to graphene in a polymer composite for orthopedic applications.

    PubMed

    Kumar, Sachin; Azam, Dilkash; Raj, Shammy; Kolanthai, Elayaraja; Vasu, K S; Sood, A K; Chatterjee, Kaushik

    2016-05-01

    Graphene-based polymer nanocomposites are being studied for biomedical applications. Polymer nanocomposites can be processed differently to generate planar two-dimensional (2D) substrates and porous three-dimensional (3D) scaffolds. The objective of this work was to investigate potential differences in biological response to graphene in polymer composites in the form of 2D substrates and 3D scaffolds. Polycaprolactone (PCL) nanocomposites were prepared by incorporating 1% of graphene oxide (GO) and reduced graphene oxide (RGO). GO increased modulus and strength of PCL by 44 and 22% respectively, whereas RGO increased modulus and strength by 22 and 16%, respectively. RGO increased the water contact angle of PCL from 81° to 87° whereas GO decreased it to 77°. In 2D, osteoblast proliferated 15% more on GO composites than on PCL whereas RGO composite showed 17% decrease in cell proliferation, which may be attributed to differences in water wettability. In 3D, initial cell proliferation was markedly retarded in both GO (36% lower) and RGO (55% lower) composites owing to increased roughness due to the presence of the protruding nanoparticles. Cells organized into aggregates in 3D in contrast to spread and randomly distributed cells on 2D discs due to the macro-porous architecture of the scaffolds. Increased cell-cell contact and altered cellular morphology led to significantly higher mineralization in 3D. This study demonstrates that the cellular response to nanoparticles in composites can change markedly by varying the processing route and has implications for designing orthopedic implants such as resorbable fracture fixation devices and tissue scaffolds using such nanocomposites.

  5. Superior lithium storage in a 3D macroporous graphene framework/SnO₂ nanocomposite.

    PubMed

    Liu, Xiaowu; Cheng, Jianxiu; Li, Weihan; Zhong, Xiongwu; Yang, Zhenzhong; Gu, Lin; Yu, Yan

    2014-07-21

    A three-dimensional (3D) interconnected graphene framework (GF)-based SnO₂ nanocomposite (3D SnO₂/GFs) was prepared using self-assembly of polystyrene (PS)@SnO₂ nanospheres and graphene oxide (GO) nanosheets under suitable pH conditions, followed by a thermal treatment. The electroactive material (SnO₂) is anchored to the wall of electrochemically and ionically conductive 3D interconnected GFs. When used as anodes for LIBs, the 3D SnO₂/GFs deliver an excellent reversible capacity (1244 mA h g(-1) in 50 cycles at 100 mA g(-1)) and outstanding rate capability (754 mA h g(-1) in 200 cycles at 1000 mA g(-1)). The ultra-small size of SnO₂ (sub 10 nm) and dimensional confinement of SnO₂ nanoparticles by the wall of GFs limit the volume expansion upon lithium insertion, and the 3D interconnected porous structures serve as buffered spaces during charge-discharge and result in superior electrochemical performance by facilitating the electrolyte to contact the entire nanocomposite materials and reduce lithium diffusion length in the nanocomposite.

  6. Scalable Preparation of Multifunctional Fire-Retardant Ultralight Graphene Foams.

    PubMed

    Hu, Chuangang; Xue, Jiangli; Dong, Liye; Jiang, Yue; Wang, Xiaopeng; Qu, Liangti; Dai, Liming

    2016-01-26

    Traditional flame-retardant materials often show poor tolerance to oxidants, strong acidic/alkaline reagents, organic solvents, along with toxicity problems. Herein, highly fire-retardant ultralight graphene foam has been developed, which possesses not only ultralight and compressible characteristics but also efficient flame-retardant properties, outperforming those traditional polymer, metallic oxide, and metal hydroxide based flame retardant materials and their composites. The newly developed unconventional refractory materials are promising for specific applications as demonstrated by the observed high temperature resistant microwave absorption capability.

  7. Controllable Synthesis of Tetraethylenepentamine Modified Graphene Foam (TEPA-GF) for the Removal of Lead ions.

    PubMed

    Han, Zhuo; Tang, Zhihong; Sun, Yuhang; Yang, Junhe; Zhi, Linjie

    2015-11-19

    3D graphene foam for water purification has become pervasive recently, not only because it has high specific surface area for adsorption capacity, but also it is easily separated from solution after adsorption. However, it is still challenging because it is hard to improve the adsorption capacity as well as maintain the high mechanical strength. To overcome the challenge, Tetraethylenepentamine modified Graphene Foam (TEPA-GF) was synthesized via a one-step hydrothermal method by using GO and TEPA as raw materials. TEPA acted as both cross-linker to combine GO sheets together and reductant of GO during hydrothermal process. Results indicated that the resultant hydrogel's formation was highly dependent on the mass ratio of TEPA to GO, they cross-linked into a stable hydrogel with perfect cylindrical only when MTEPA: MGO ≥ 1. What's more, the highest mechanical strength of GF happened at the mass ratio of MTEPA: MGO = 3, which was up to 0.58 kPa. It was worth noting that TEPA-GF demonstrated high adsorption capacity for lead ions, which reached as high as 304.9 mg g(-1), much higher than that of other absorbents. Furthermore, TEPA-GF was easily separated from water after adsorption of Pb(2+), making it a great potential material for water purification.

  8. Controllable Synthesis of Tetraethylenepentamine Modified Graphene Foam (TEPA-GF) for the Removal of Lead ions

    NASA Astrophysics Data System (ADS)

    Han, Zhuo; Tang, Zhihong; Sun, Yuhang; Yang, Junhe; Zhi, Linjie

    2015-11-01

    3D graphene foam for water purification has become pervasive recently, not only because it has high specific surface area for adsorption capacity, but also it is easily separated from solution after adsorption. However, it is still challenging because it is hard to improve the adsorption capacity as well as maintain the high mechanical strength. To overcome the challenge, Tetraethylenepentamine modified Graphene Foam (TEPA-GF) was synthesized via a one-step hydrothermal method by using GO and TEPA as raw materials. TEPA acted as both cross-linker to combine GO sheets together and reductant of GO during hydrothermal process. Results indicated that the resultant hydrogel’s formation was highly dependent on the mass ratio of TEPA to GO, they cross-linked into a stable hydrogel with perfect cylindrical only when MTEPA: MGO ≥ 1. What’s more, the highest mechanical strength of GF happened at the mass ratio of MTEPA: MGO = 3, which was up to 0.58 kPa. It was worth noting that TEPA-GF demonstrated high adsorption capacity for lead ions, which reached as high as 304.9 mg g-1, much higher than that of other absorbents. Furthermore, TEPA-GF was easily separated from water after adsorption of Pb2+, making it a great potential material for water purification.

  9. Controllable Synthesis of Tetraethylenepentamine Modified Graphene Foam (TEPA-GF) for the Removal of Lead ions

    PubMed Central

    Han, Zhuo; Tang, Zhihong; Sun, Yuhang; Yang, Junhe; Zhi, Linjie

    2015-01-01

    3D graphene foam for water purification has become pervasive recently, not only because it has high specific surface area for adsorption capacity, but also it is easily separated from solution after adsorption. However, it is still challenging because it is hard to improve the adsorption capacity as well as maintain the high mechanical strength. To overcome the challenge, Tetraethylenepentamine modified Graphene Foam (TEPA-GF) was synthesized via a one-step hydrothermal method by using GO and TEPA as raw materials. TEPA acted as both cross-linker to combine GO sheets together and reductant of GO during hydrothermal process. Results indicated that the resultant hydrogel’s formation was highly dependent on the mass ratio of TEPA to GO, they cross-linked into a stable hydrogel with perfect cylindrical only when MTEPA: MGO ≥ 1. What’s more, the highest mechanical strength of GF happened at the mass ratio of MTEPA: MGO = 3, which was up to 0.58 kPa. It was worth noting that TEPA-GF demonstrated high adsorption capacity for lead ions, which reached as high as 304.9 mg g−1, much higher than that of other absorbents. Furthermore, TEPA-GF was easily separated from water after adsorption of Pb2+, making it a great potential material for water purification. PMID:26581493

  10. Hydrous Ruthenium Oxide Nanoparticles Anchored to Graphene and Carbon Nanotube Hybrid Foam for Supercapacitors

    PubMed Central

    Wang, Wei; Guo, Shirui; Lee, Ilkeun; Ahmed, Kazi; Zhong, Jiebin; Favors, Zachary; Zaera, Francisco; Ozkan, Mihrimah; Ozkan, Cengiz S.

    2014-01-01

    In real life applications, supercapacitors (SCs) often can only be used as part of a hybrid system together with other high energy storage devices due to their relatively lower energy density in comparison to other types of energy storage devices such as batteries and fuel cells. Increasing the energy density of SCs will have a huge impact on the development of future energy storage devices by broadening the area of application for SCs. Here, we report a simple and scalable way of preparing a three-dimensional (3D) sub-5 nm hydrous ruthenium oxide (RuO2) anchored graphene and CNT hybrid foam (RGM) architecture for high-performance supercapacitor electrodes. This RGM architecture demonstrates a novel graphene foam conformally covered with hybrid networks of RuO2 nanoparticles and anchored CNTs. SCs based on RGM show superior gravimetric and per-area capacitive performance (specific capacitance: 502.78 F g−1, areal capacitance: 1.11 F cm−2) which leads to an exceptionally high energy density of 39.28 Wh kg−1 and power density of 128.01 kW kg−1. The electrochemical stability, excellent capacitive performance, and the ease of preparation suggest this RGM system is promising for future energy storage applications. PMID:24663242

  11. Hydrous ruthenium oxide nanoparticles anchored to graphene and carbon nanotube hybrid foam for supercapacitors

    SciTech Connect

    Wang, Wei; Guo, S.; Lee, I.; Ahmed, K.; Zhong, J.; Favors, Z.; Zaera, F.; Ozkan, M.; Ozkan, C. S

    2014-03-25

    In real life applications, supercapacitors (SCs) often can only be used as part of a hybrid system together with other high energy storage devices due to their relatively lower energy density in comparison to other types of energy storage devices such as batteries and fuel cells. Increasing the energy density of SCs will have a huge impact on the development of future energy storage devices by broadening the area of application for SCs. Here, we report a simple and scalable way of preparing a three-dimensional (3D) sub-5 nm hydrous ruthenium oxide (RuO₂) anchored graphene and CNT hybrid foam (RGM) architecture for high-performance supercapacitor electrodes. This RGM architecture demonstrates a novel graphene foam conformally covered with hybrid networks of RuO₂ nanoparticles and anchored CNTs. SCs based on RGM show superior gravimetric and per-area capacitive performance (specific capacitance: 502.78 F g⁻¹, areal capacitance: 1.11 F cm⁻²) which leads to an exceptionally high energy density of 39.28 Wh kg⁻¹ and power density of 128.01 kW kg⁻¹. The electrochemical stability, excellent capacitive performance, and the ease of preparation suggest this RGM system is promising for future energy storage applications.

  12. Hydrous Ruthenium Oxide Nanoparticles Anchored to Graphene and Carbon Nanotube Hybrid Foam for Supercapacitors

    NASA Astrophysics Data System (ADS)

    Wang, Wei; Guo, Shirui; Lee, Ilkeun; Ahmed, Kazi; Zhong, Jiebin; Favors, Zachary; Zaera, Francisco; Ozkan, Mihrimah; Ozkan, Cengiz S.

    2014-03-01

    In real life applications, supercapacitors (SCs) often can only be used as part of a hybrid system together with other high energy storage devices due to their relatively lower energy density in comparison to other types of energy storage devices such as batteries and fuel cells. Increasing the energy density of SCs will have a huge impact on the development of future energy storage devices by broadening the area of application for SCs. Here, we report a simple and scalable way of preparing a three-dimensional (3D) sub-5 nm hydrous ruthenium oxide (RuO2) anchored graphene and CNT hybrid foam (RGM) architecture for high-performance supercapacitor electrodes. This RGM architecture demonstrates a novel graphene foam conformally covered with hybrid networks of RuO2 nanoparticles and anchored CNTs. SCs based on RGM show superior gravimetric and per-area capacitive performance (specific capacitance: 502.78 F g-1, areal capacitance: 1.11 F cm-2) which leads to an exceptionally high energy density of 39.28 Wh kg-1 and power density of 128.01 kW kg-1. The electrochemical stability, excellent capacitive performance, and the ease of preparation suggest this RGM system is promising for future energy storage applications.

  13. Hyperbolically Patterned 3D Graphene Metamaterial with Negative Poisson's Ratio and Superelasticity.

    PubMed

    Zhang, Qiangqiang; Xu, Xiang; Lin, Dong; Chen, Wenli; Xiong, Guoping; Yu, Yikang; Fisher, Timothy S; Li, Hui

    2016-03-16

    A hyperbolically patterned 3D graphene metamaterial (GM) with negative Poisson's ratio and superelasticity is highlighted. It is synthesized by a modified hydrothermal approach and subsequent oriented freeze-casting strategy. GM presents a tunable Poisson's ratio by adjusting the structural porosity, macroscopic aspect ratio (L/D), and freeze-casting conditions. Such a GM suggests promising applications as soft actuators, sensors, robust shock absorbers, and environmental remediation.

  14. Harnessing Three Dimensional Anatomy of Graphene Foam to Induce Superior Damping in Hierarchical Polyimide Nanostructures.

    PubMed

    Nautiyal, Pranjal; Boesl, Benjamin; Agarwal, Arvind

    2017-03-01

    Graphene foam-based hierarchical polyimide composites with nanoengineered interface are fabricated in this study. Damping behavior of graphene foam is probed for the first time. Multiscale mechanisms contribute to highly impressive damping in graphene foam. Rippling, spring-like interlayer van der Waals interactions and flexing of graphene foam branches are believed to be responsible for damping at the intrinsic, interlayer and anatomical scales, respectively. Merely 1.5 wt% graphene foam addition to the polyimide matrix leads to as high as ≈300% improvement in loss tangent. Graphene nanoplatelets are employed to improve polymer-foam interfacial adhesion by arresting polymer shrinkage during imidization and π-π interactions between nanoplatelets and foam walls. As a result, damping behavior is further improved due to effective stress transfer from the polymer matrix to the foam. Thermo-oxidative stability of these nanocomposites is investigated by exposing the specimens to glass transition temperature of the polyimide (≈400 °C). The composites are found to retain their damping characteristics even after being subjected to such extreme temperature, attesting their suitability in high temperature structural applications. Their unique hierarchical nanostructure provides colossal opportunity to engineer and program material properties.

  15. Fabrication of light, flexible and multifunctional graphene nanoribbon fibers via a 3D solution printing method.

    PubMed

    Wang, Mingqiang; Zhang, Shuai; Song, Yuanjun; Dong, Jidong; Wei, Huawei; Xie, Huaquan; Fang, Xiaojiao; Shao, Lu; Huang, Yudong; Jiang, Zaixing

    2016-11-18

    Graphene oxide nanoribbons (GONRs) are one of the most promising carbon based materials. The integration of 2D GONR sheets into macroscopic materials, such as continuous fibers or film, leads the way in translating the good properties of individual GONR sheets into macroscopic and ordered materials for future applications. In this study, we first report the fabrication of GONR fibers utilizing GONR sheets as the raw material without any supporting surfactant or polymer. The method of fabricating fibers is referred to as '3D solution printing'. GONR fibers exhibit good mechanical and electrical properties, whose tensile strength and electrical conductivity could reach up to 95 MPa and 680 S cm(-1), respectively. Hence, the fabricated 3D integrated circuits are lighter and smaller compared to traditional metal circuits, and with high electrical properties. The 3D integrated circuits, therefore, have a bright future prospect.

  16. Fabrication of light, flexible and multifunctional graphene nanoribbon fibers via a 3D solution printing method

    NASA Astrophysics Data System (ADS)

    Wang, Mingqiang; Zhang, Shuai; Song, Yuanjun; Dong, Jidong; Wei, Huawei; Xie, Huaquan; Fang, Xiaojiao; Shao, Lu; Huang, Yudong; Jiang, Zaixing

    2016-11-01

    Graphene oxide nanoribbons (GONRs) are one of the most promising carbon based materials. The integration of 2D GONR sheets into macroscopic materials, such as continuous fibers or film, leads the way in translating the good properties of individual GONR sheets into macroscopic and ordered materials for future applications. In this study, we first report the fabrication of GONR fibers utilizing GONR sheets as the raw material without any supporting surfactant or polymer. The method of fabricating fibers is referred to as ‘3D solution printing’. GONR fibers exhibit good mechanical and electrical properties, whose tensile strength and electrical conductivity could reach up to 95 MPa and 680 S cm-1, respectively. Hence, the fabricated 3D integrated circuits are lighter and smaller compared to traditional metal circuits, and with high electrical properties. The 3D integrated circuits, therefore, have a bright future prospect.

  17. Graphene oxide foams and their excellent adsorption ability for acetone gas

    SciTech Connect

    He, Yongqiang; Zhang, Nana; Wu, Fei; Xu, Fangqiang; Liu, Yu; Gao, Jianping

    2013-09-01

    Graphical abstract: - Highlights: • GO and RGO foams were prepared using a simple and green method, unidirectional freeze-drying. • The porous structure of the foams can be adjusted by changing GO concentrations. • GO and RGO foams show good adsorption efficiency for acetone gas. - Abstract: Graphene oxide (GO) and reduced graphene oxide (RGO) foams were prepared using a unidirectional freeze-drying method. These porous carbon materials were characterized by thermal gravimetric analysis, differential scanning calorimetry, X-ray photoelectron spectroscopy and scanning electron microscopy. The adsorption behavior of the two kinds of foams for acetone was studied. The result showed that the saturated adsorption efficiency of the GO foams was over 100%, and was higher than that of RGO foams and other carbon materials.

  18. Flyweight 3D Graphene Scaffolds with Microinterface Barrier-Derived Tunable Thermal Insulation and Flame Retardancy.

    PubMed

    Zhang, Qiangqiang; Hao, Menglong; Xu, Xiang; Xiong, Guoping; Li, Hui; Fisher, Timothy S

    2017-04-14

    In this article, flyweight three-dimensional (3D) graphene scaffolds (GSs) have been demonstrated with a microinterface barrier-derived thermal insulation and flame retardancy characteristics. Such 3D GSs were fabricated by a modified hydrothermal method and a unidirectional freeze-casting process with hierarchical porous microstructures. Because of high porosity (99.9%), significant phonon scattering, and strong π-π interaction at the interface barriers of multilayer graphene cellular walls, the GSs demonstrate a sequence of multifunctional properties simultaneously, such as lightweight density, thermal insulating characteristics, and outstanding mechanical robustness. At 100 °C, oxidized GSs exhibit a thermal conductivity of 0.0126 ± 0.0010 W/(m K) in vacuum. The thermal conductivity of oxidized GSs remains relatively unaffected despite large-scale deformation-induced densification of the microstructures, as compared to the behavior of reduced GSs (rGSs) whose thermal conductivity increases dramatically under compression. The contrasting behavior of oxidized GSs and rGSs appears to derive from large differences in the intersheet contact resistance and varying intrinsic thermal conductivity between reduced and oxidized graphene sheets. The oxidized GSs also exhibit excellent flame retardant behavior and mechanical robustness, with only 2% strength decay after flame treatment. In a broader context, this work demonstrates a useful strategy to design porous nanomaterials with a tunable heat conduction behavior through interface engineering at the nanoscale.

  19. 3-D Wizardry: Design in Papier-Mache, Plaster, and Foam.

    ERIC Educational Resources Information Center

    Wolfe, George

    Papier-mache, plaster, and foam are inexpensive and versatile media for 3-dimensional classroom and studio art experiences. They can be used equally well by elementary, high school, or college students. Each medium has its own characteristic. Papier-mache is pliable but dries into a hard, firm surface that can be waterproofed. Plaster can be…

  20. High temperature dependence of thermal transport in graphene foam

    NASA Astrophysics Data System (ADS)

    Li, Man; Sun, Yi; Xiao, Huying; Hu, Xuejiao; Yue, Yanan

    2015-03-01

    In contrast to the decreased thermal property of carbon materials with temperature according to the Umklapp phonon scattering theory, highly porous free-standing graphene foam (GF) exhibits an abnormal characteristic that its thermal property increases with temperature above room temperature. In this work, the temperature dependence of thermal properties of free-standing GF is investigated by using the transient electro-thermal technique. Significant increase for thermal conductivity and thermal diffusivity from ˜0.3 to 1.5 W m-1 K-1 and ˜4 × 10-5 to ˜2 × 10-4 m2 s-1 respectively is observed with temperature from 310 K to 440 K for three GF samples. The quantitative analysis based on a physical model for porous media of Schuetz confirms that the thermal conductance across graphene contacts rather than the heat conductance inside graphene dominates thermal transport of our GFs. The thermal expansion effect at an elevated temperature makes the highly porous structure much tighter is responsible for the reduction in thermal contact resistance. Besides, the radiation heat exchange inside the pores of GFs improves the thermal transport at high temperatures. Since free-standing GF has great potential for being used as supercapacitor and battery electrode where the working temperature is always above room temperature, this finding is beneficial for thermal design of GF-based energy applications.

  1. Three-dimensional nitrogen-doped graphene foam as metal-free catalyst for the hydrogenation reduction of p-nitrophenol.

    PubMed

    Liu, Jiangyong; Yan, Xiaodong; Wang, Lixia; Kong, Liming; Jian, Panming

    2017-07-01

    Developing metal-free catalysts for various applications has been the focus of high interest over the past decade, especially aiming to replace the expensive noble metal-based catalysts. Herein, a well-defined three-dimensional nitrogen-doped graphene foam (3D-NGF) is synthesized and employed as a metal-free catalyst for the hydrogenation reduction of p-Nitrophenol to p-Aminophenol. The apparent activation energy is calculated, and the reaction mechanism with 3D-NGF as the catalyst for the hydrogenation reduction of p-Nitrophenol is proposed. Importantly, the 3D-NGF demonstrates high catalytic activity and robust stability. The high activity can be ascribed to the synergistic effect between the nitrogen-doping induced change in electronic property and the 3D foam-like structure.

  2. 3D graphene nano-grid as a homogeneous protein distributor for ultrasensitive biosensors.

    PubMed

    Chu, Zhenyu; Shi, Lei; Jin, Wanqin

    2014-11-15

    In order to realize the protein uniform immobilization, a 3D nano-gird architecture of thiol grafted graphene film was fabricated to serve as a novel linker between protein and substrate. Relied on the online monitor by QCM, graphene deposition process can be exactly controlled to construct the perfect and continuous cavities with the consistent size of 500 nm. The synergetic characterization of FESEM and Nano-indentation characterizations have revealed the strong stability of grid structure to provide a firm foundation for further protein adsorption. Instead of common partial aggregation behavior, proteins can be spontaneously distributed into cavities by the interaction from thiol group. According to the verifications of various proteins, the efficiency of this distributor will not be constricted by the category and amount of protein, which exhibit its versatility of homogeneous distribution. Glucose and lactate oxidase loaded graphene distributors were directly served as biosensors to verify the superiority of distribution. Their sensitivities can be remarkably improved three times since the adoption of this nano-grid structured graphene distributor.

  3. The improved electrochemical performance of cross-linked 3D graphene nanoribbon monolith electrodes

    NASA Astrophysics Data System (ADS)

    Vineesh, Thazhe Veettil; Alwarappan, Subbiah; Narayanan, Tharangattu N.

    2015-04-01

    Technical advancement in the field of ultra-small sensors and devices demands the development of novel micro- or nano-based architectures. Here we report the design and assembly of cross-linked three dimensional graphene nanoribbons (3D GNRs) using solution based covalent binding of individual 2D GNRs and demonstrate its electrochemical application as a 3D electrode. The enhanced performance of 3D GNRs over individual 2D GNRs is established using standard redox probes - [Ru(NH3)6]3+/2+, [Fe(CN)6]3-/4- and important bio-analytes - dopamine and ascorbic acid. 3D GNRs are found to have high double layer capacitance (2482 μF cm-2) and faster electron transfer kinetics; their exceptional electrocatalytic activity towards the oxygen reduction reaction is indicative of their potential over a wide range of electrochemical applications. Moreover, this study opens a new platform for the design of novel point-of-care devices and electrodes for energy devices.Technical advancement in the field of ultra-small sensors and devices demands the development of novel micro- or nano-based architectures. Here we report the design and assembly of cross-linked three dimensional graphene nanoribbons (3D GNRs) using solution based covalent binding of individual 2D GNRs and demonstrate its electrochemical application as a 3D electrode. The enhanced performance of 3D GNRs over individual 2D GNRs is established using standard redox probes - [Ru(NH3)6]3+/2+, [Fe(CN)6]3-/4- and important bio-analytes - dopamine and ascorbic acid. 3D GNRs are found to have high double layer capacitance (2482 μF cm-2) and faster electron transfer kinetics; their exceptional electrocatalytic activity towards the oxygen reduction reaction is indicative of their potential over a wide range of electrochemical applications. Moreover, this study opens a new platform for the design of novel point-of-care devices and electrodes for energy devices. Electronic supplementary information (ESI) available. See DOI: 10.1039/c

  4. 3D hierarchical porous graphene aerogel with tunable meso-pores on graphene nanosheets for high-performance energy storage

    PubMed Central

    Ren, Long; Hui, K. N.; Hui, K. S.; Liu, Yundan; Qi, Xiang; Zhong, Jianxin; Du, Yi; Yang, Jianping

    2015-01-01

    New and novel 3D hierarchical porous graphene aerogels (HPGA) with uniform and tunable meso-pores (e.g., 21 and 53 nm) on graphene nanosheets (GNS) were prepared by a hydrothermal self-assembly process and an in-situ carbothermal reaction. The size and distribution of the meso-pores on the individual GNS were uniform and could be tuned by controlling the sizes of the Co3O4 NPs used in the hydrothermal reaction. This unique architecture of HPGA prevents the stacking of GNS and promises more electrochemically active sites that enhance the electrochemical storage level significantly. HPGA, as a lithium-ion battery anode, exhibited superior electrochemical performance, including a high reversible specific capacity of 1100 mAh/g at a current density of 0.1 A/g, outstanding cycling stability and excellent rate performance. Even at a large current density of 20 A/g, the reversible capacity was retained at 300 mAh/g, which is larger than that of most porous carbon-based anodes reported, suggesting it to be a promising candidate for energy storage. The proposed 3D HPGA is expected to provide an important platform that can promote the development of 3D topological porous systems in a range of energy storage and generation fields. PMID:26382852

  5. Morphology-Tuned Synthesis of NiCo2 O4 -Coated 3D Graphene Architectures Used as Binder-Free Electrodes for Lithium-Ion Batteries.

    PubMed

    Zhang, Chunfei; Yu, Jong-Sung

    2016-03-18

    Nanostructured NiCo2O4 is directly grown on the surface of three-dimensional graphene-coated nickel foam (3D-GNF) by a facile electrodeposition technique and subsequent annealing. The resulting NiCo2O4 possesses a distinct flower or sheet morphology, tuned by potential or current variation electrodeposition, which are used as binder-free lithium-ion battery anodes for the first time. Both samples exhibit high lithium storage capacity, profiting from the unique binder-free electrode structures. The flower-type NiCo2O4 demonstrates high reversible discharge capacity (1459 mAh g(-1) at 200 mA g(-1)) and excellent cyclability with around 71% retention of the reversible capacity after 60 cycles, which are superior to the sheet-type NiCo2O4. Such superb performance can be attributed to high volume utilization efficiency with unique morphological character, a well-preserved connection between the active materials and the current collector, a short lithium-ion diffusion path, and fast electrolyte transfer in the binder-free NiCo2O4 coated 3D graphene structure. The simple preparation process and easily controllable morphology make the binder-free NiCo2O4/3D-GNF hybrid a potential material for commercial applications.

  6. 3D MoS2-graphene hybrid aerogels as catalyst for enhanced efficient hydrogen evolution

    NASA Astrophysics Data System (ADS)

    Xu, Xiaobing; Sun, Yuan; Qiao, Wen; Zhang, Xing; Chen, Xing; Song, Xueyin; Wu, Liqian; Zhong, Wei; Du, Youwei

    2017-02-01

    Aerogel composite materials consisting of MoS2 and reduced graphite oxide (rGO) are synthesized by a facile general hydrothermal method, where GO is utilized as a template and provides a novel substrate for the nucleation and subsequent growth of MoS2. These MoS2/rGO hybrid nanostructures exhibit three-dimensional (3D) leaf-like morphology, and show excellent electrocatalytic activities of hydrogen evolution reaction (HER), with a low overpotential of approximately 105 mV, a small Tafel slope of 51 mV/dec and a large exchange current density (j0) of 3.28 × 10-5 A/cm2. The superior electrochemical performance should be attributed to the 3D porous MoS2/rGO hybrid architecture, which enhances the conductivity from graphene to MoS2 as well as the HER activity.

  7. 3D Printing Biocompatible Polyurethane/Poly(lactic acid)/Graphene Oxide Nanocomposites: Anisotropic Properties.

    PubMed

    Chen, Qiyi; Mangadlao, Joey Dacula; Wallat, Jaqueline; De Leon, Al; Pokorski, Jonathan K; Advincula, Rigoberto C

    2017-02-01

    Blending thermoplastic polyurethane (TPU) with poly(lactic acid) (PLA) is a proven method to achieve a much more mechanically robust material, whereas the addition of graphene oxide (GO) is increasingly applied in polymer nanocomposites to tailor further their properties. On the other hand, additive manufacturing has high flexibility of structure design which can significantly expand the application of materials in many fields. This study demonstrates the fused deposition modeling (FDM) 3D printing of TPU/PLA/GO nanocomposites and its potential application as biocompatible materials. Nanocomposites are prepared by solvent-based mixing process and extruded into filaments for FDM printing. The addition of GO largely enhanced the mechanical property and thermal stability of the nanocomposites. Interestingly, we found that the mechanical response is highly dependent on printing orientation. Furthermore, the 3D printed nanocomposites exhibit good biocompatibility with NIH3T3 cells, indicating promise as biomaterials scaffold for tissue engineering applications.

  8. Pt-decorated 3D architectures built from graphene and graphitic carbon nitride nanosheets as efficient methanol oxidation catalysts.

    PubMed

    Huang, Huajie; Yang, Shubin; Vajtai, Robert; Wang, Xin; Ajayan, Pulickel M

    2014-08-13

    Homogeneous dispersion of ultrafine Pt nanoparticles on 3D architectures constructed of graphene and exfoliated graphitic carbon nitride results in hybrids with 3D porous structures, large surface area, high nitrogen content, and good electrical conductivity. This leads to excellent electrocatalytic activity, unusually high poison tolerance, and reliable stability for methanol oxidation, making them of interest as catalysts in direct methanol fuel cells.

  9. Preparation of graphene foam with high performance by modified self-assembly method

    NASA Astrophysics Data System (ADS)

    Zhang, Wenhui; Sun, Youyi; Liu, Tantan; Li, Diansen; Hou, Chunlin; Gao, Li; Liu, Yaqing

    2016-03-01

    Recently, self-assembly method was applied for preparation of graphene foam. However, it is still a great challenge to obtain a three-dimensional graphene network with high performance (e.g., low density, high mechanical strength and high conductivity together) for the self-assembly method. Herein, a modified self-assembly method applied for preparation of graphene foam was investigated, in which, L-ascorbic acid and HI were firstly chosen as the reducing agent, and further reduced by hydrazine hydrate. The results demonstrated that the graphene foam showed high compressive strength (ca. 320 kPa), high electrical conductivity (20.6 S/m) and low density (14.7 mg/cm-1). Especially, the obtained compressive strength (ca. 320 kPa) is the highest value compared to the data of graphene foam reported in previous works. This phenomenon may be due to following three reasons: (1) the reaction between hydrazine hydrate and graphene brought some covalent bonds among graphene sheets; (2) graphene foam was achieved by high hydrophobicity and electrostatic repulsion which inhibit the restacking of graphene sheets; (3) the removal of the oxygen groups by hydrazine hydrate efficiently restores conjugation of sp2 regions and the π-π interaction in the cross-linking sites, which tightly bonds the sheets together. The obtained graphene foam not only had good porous structure and mechanical strength, but also showed excellent satisfactory double-layer capacitive behavior with good electrochemical cyclic stability and high specific capacitance of 171.0 F/g for application in electrode of supercapacitors and absorption capacities for the removal of various oils and dyes from water.

  10. A Robust and Cost-Effective Superhydrophobic Graphene Foam for Efficient Oil and Organic Solvent Recovery.

    PubMed

    Zhu, Haiguang; Chen, Dongyun; An, Wei; Li, Najun; Xu, Qingfeng; Li, Hua; He, Jinghui; Lu, Jianmei

    2015-10-21

    Water pollution caused by chemical reagent leaking, industrial wastewater discharging, and crude oil spills has raised global concerns on environmental sustainability, calling for high-performance absorbent materials for effective treatments. However, low-cost materials capable of effectively separating oils and organic solvents from water with a high adsorption capacity and good recyclability are rare on the market. Here, a cost-effective method is reported to fabricate high-performance graphene modified absorbents through the facile thermal reduction of graphene oxide on the skeletons of melamine foam. By integrating the high porosity, superior elasticity, and mechanical stability of raw sponge with the chemical stability and hydrophobicity of graphene sheets, the as-fabricated graphene foam not only possesses a rough and superhydrophobic surface, but also exhibits an excellent adsorption performance and extraordinary recyclability for various oils and organic solvents. It is worth mentioning that the superhydrophobic surface also endows the graphene foam with an excellent efficiency for oil/water separation. More importantly, the cost-effective fabrication method without involving expensive raw materials and sophisticated equipment permits a scale-up of the graphene foam for pollution disposal. All these features make the graphene foam an ideal candidate for removal and collection of oils and organic solvents from water.

  11. Comparison of the bubble size distribution in silicate foams using 2D images and 3D x-ray microtomography

    NASA Astrophysics Data System (ADS)

    Robert, Genevieve; Baker, Don R.; Rivers, Mark L.; Allard, Emilie; Larocque, Jeffery

    2004-10-01

    Three silicate glasses were hydrated at high pressure and then heated at atmospheric pressure to exsolve the water into bubbles and create foams. The bubble size distribution in these foams was measured by x-ray microtomography on the GSECARS BM-13 beamline at the Advanced Photon Source. The bubble area distributions were measured in two dimensions using the image slices produced from the microtomography and the software ImageJ. The bubble volume distributions were measured from the three-dimensional tomographic images with the BLOB3D software. We found that careful analysis of the microtomography data in both two and three dimensions was necessary to avoid the physically unrealistic, experimental artifact of identifying and counting many small bubbles whose surfaces were not defined by a septum of glass. When this artifact was avoided the foams demonstrated power-law distributions of bubble sizes in both two and three dimensions. Conversion of the power-law exponents for bubble areas measured in two dimensions to exponents for bubble volumes usually agreed with the measured three dimensional volume exponents. Furthermore, the power-law distributions for bubble volumes typically agree with multiple theories of bubble growth, all of which yield an exponent of 1 for the cumulative bubble volume distribution. The measured bubble volume distributions with exponents near 0.3 can be explained by diffusive growth as proposed by other authors, but distributions with exponents near 1.4 remain to be explained and are the subject of continuing research on the effects of water concentration and melt viscosity on foaming behavior.

  12. Graphene-based 3D composite hydrogel by anchoring Co3O4 nanoparticles with enhanced electrochemical properties.

    PubMed

    Yuan, Jingjing; Zhu, Junwu; Bi, Huiping; Meng, Xiaoqian; Liang, Shiming; Zhang, Lili; Wang, Xin

    2013-08-21

    Three-dimensional (3D) graphene-based composite materials have attracted increasing attention, owing to their specific surface area, high conductivity and electronic interactions. Here, we report a convenient route to fabricate a 3D Co3O4/Graphene Hydrogel (CGH) composite as an electrode material for supercapacitors. Utilizing the gelation of a graphene oxide dispersion enables the anchoring of Co3O4 nanoparticles on the graphene sheet surfaces and formation of the hydrogel simultaneously. Remarkably, the spherical Co3O4 particles can serve as spacers to keep the neighboring graphene sheets separated. The CGH exhibits a high specific capacitance (Cs) of 757.5 F g(-1) at a current density of 0.5 A g(-1), indicating its potential application as an electrode material for supercapacitors.

  13. 3D-Printed Multidrug-Eluting Stent from Graphene-Nanoplatelet-Doped Biodegradable Polymer Composite.

    PubMed

    Misra, Santosh K; Ostadhossein, Fatemeh; Babu, Ramya; Kus, Joseph; Tankasala, Divya; Sutrisno, Andre; Walsh, Kathleen A; Bromfield, Corinne R; Pan, Dipanjan

    2017-03-21

    Patients with percutaneous coronary intervention generally receive either bare metal stents or drug-eluting stents to restore the normal blood flow. However, due to the lack of stent production with an individual patient in mind, the same level of effectiveness may not be possible in treating two different clinical scenarios. This study introduces for the first time the feasibility of a patient-specific stenting process constructed from direct 3D segmentation of medical images using direct 3D printing of biodegradable polymer-graphene composite with dual drug incorporation. A biodegradable polymer-carbon composite is prepared doped with graphene nanoplatelets to achieve controlled release of combinatorics as anticoagulation and antirestenosis agents. This study develops a technology prototyped for personalized stenting. An in silico analysis is performed to optimize the stent design for printing and its prediction of sustainability under force exerted by coronary artery or blood flow. A holistic approach covering in silico to in situ-in vivo establishes the structural integrity of the polymer composite, its mechanical properties, drug loading and release control, prototyping, functional activity, safety, and feasibility of placement in coronary artery of swine.

  14. A novel graphene based nanocomposite for application in 3D flexible micro-supercapacitors

    NASA Astrophysics Data System (ADS)

    Marasso, S. L.; Rivolo, P.; Giardi, R.; Mombello, D.; Gigot, A.; Serrapede, M.; Benetto, S.; Enrico, A.; Cocuzza, M.; Tresso, E.; Pirri, C. F.

    2016-06-01

    In this work a hybrid graphene-based flexible micro-supercapacitor (MSC) exploiting a novel composite material was fabricated and extensively characterized. The MSC electrodes have been obtained from a synthesized composite aerogel of reduced graphene oxide and polycrystalline nanoparticles of molybdenum (IV) oxide (MoO2) and then dispersed in a solution containing poly(3,4-ethylenedioxythiophene) (PEDOT). Usually in MSCs the electrons have to percolate through the nanostructured Three-dimensional (3D) matrix in order to reach the collectors, made by metal thin films that provide electrical contacts only on the surface of active material. In the attempt to enable a more efficient charge transfer and to allow direct electrical contact without metal deposition, in this study a highly doped PEDOT acting both as current collector and as binder for the nanocomposite material has been employed. 3D MSCs were fabricated through a Lithographie, Galvanoformung, Abformung (LIGA)-like process to obtain high aspect ratio microstructures in polydimethylsiloxane replicas. Capacitance values of 94 F g-1 for the nanocomposite and of 14 mF cm-2 for the device were achieved. Moreover, bending test has demonstrated good performance preservation in a U shape conformation of the device.

  15. Rapid microwave-assisted growth of silver nanoparticles on 3D graphene networks for supercapacitor application.

    PubMed

    Khamlich, S; Khamliche, T; Dhlamini, M S; Khenfouch, M; Mothudi, B M; Maaza, M

    2017-05-01

    Silver nanoparticles (AgNPs) grown on a three dimensional (3d) graphene networks (GNs) has been successfully prepared by an efficient and rapid microwave-assisted growth process to form GNs/AgNPs nanocomposite electrode materials for supercapacitor application. The 3d nature of the used GNs offers a unique architecture, which creates an efficient conduction networks and maximum utilization of space and interface, and acts as a conductive layer for the deposited AgNPs. The electrochemical performances of the fabricated electrode were evaluated by cyclic voltammetry (CV), galvanostatic charge/discharge and electrochemical impedance spectroscopy (EIS) tests. Specifically, the optimal GNs/AgNPs nanocomposite exhibits remarkable performances with a high specific capacitance of 528Fg(-1) at a current density of 1Ag(-1) and excellent capacitance retention of ∼93% after 3000cycles. Moreover, this microwave-assisted growth strategy of AgNPs is simple and effective, which could be extended to the construction of other three dimensional graphene based metallic composites for energy storage and conversion applications.

  16. Binder free three-dimensional sulphur/few-layer graphene foam cathode with enhanced high-rate capability for rechargeable lithium sulphur batteries.

    PubMed

    Xi, Kai; Kidambi, Piran R; Chen, Renjie; Gao, Chenlong; Peng, Xiaoyu; Ducati, Caterina; Hofmann, Stephan; Kumar, R Vasant

    2014-06-07

    A novel ultra-lightweight three-dimensional (3-D) cathode system for lithium sulphur (Li-S) batteries has been synthesised by loading sulphur on to an interconnected 3-D network of few-layered graphene (FLG) via a sulphur solution infiltration method. A free-standing FLG monolithic network foam was formed as a negative of a Ni metallic foam template by CVD followed by etching away of Ni. The FLG foam offers excellent electrical conductivity, an appropriate hierarchical pore structure for containing the electro-active sulphur and facilitates rapid electron/ion transport. This cathode system does not require any additional binding agents, conductive additives or a separate metallic current collector thus decreasing the weight of the cathode by typically ∼20-30 wt%. A Li-S battery with the sulphur-FLG foam cathode shows good electrochemical stability and high rate discharge capacity retention for up to 400 discharge/charge cycles at a high current density of 3200 mA g(-1). Even after 400 cycles the capacity decay is only ∼0.064% per cycle relative to the early (e.g. the 5th cycle) discharge capacity, while yielding an average columbic efficiency of ∼96.2%. Our results indicate the potential suitability of graphene foam for efficient, ultra-light and high-performance batteries.

  17. High-performance hybrid supercapacitor with 3D hierarchical porous flower-like layered double hydroxide grown on nickel foam as binder-free electrode

    NASA Astrophysics Data System (ADS)

    Zhang, Luojiang; Hui, Kwun Nam; San Hui, Kwan; Lee, Haiwon

    2016-06-01

    The synthesis of layered double hydroxide (LDH) as electroactive material has been well reported; however, fabricating an LDH electrode with excellent electrochemical performance at high current density remains a challenge. In this paper, we report a 3D hierarchical porous flower-like NiAl-LDH grown on nickel foam (NF) through a liquid-phase deposition method as a high-performance binder-free electrode for energy storage. With large ion-accessible surface area as well as efficient electron and ion transport pathways, the prepared LDH-NF electrode achieves high specific capacity (1250 C g-1 at 2 A g-1 and 401 C g-1 at 50 A g-1) after 5000 cycles of activation at 20 A g-1 and high cycling stability (76.7% retention after another 5000 cycles at 50 A g-1), which is higher than those of most previously reported NiAl-LDH-based materials. Moreover, a hybrid supercapacitor with LDH-NF as the positive electrode and porous graphene nanosheet coated on NF (GNS-NF) as the negative electrode, delivers high energy density (30.2 Wh kg-1 at a power density of 800 W kg-1) and long cycle life, which outperforms the other devices reported in the literature. This study shows that the prepared LDH-NF electrode offers great potential in energy storage device applications.

  18. Dechlorination of Trichloroacetic Acid Using a Noble Metal-Free Graphene-Cu Foam Electrode via Direct Cathodic Reduction and Atomic H.

    PubMed

    Mao, Ran; Li, Ning; Lan, Huachun; Zhao, Xu; Liu, Huijuan; Qu, Jiuhui; Sun, Meng

    2016-04-05

    A three-dimensional graphene-copper (3D GR-Cu) foam electrode prepared by chemical vapor deposition method exhibited superior electrocatalytic activity toward the dechlorination of trichloroacetic acid (TCAA) as compared to the Cu foam electrode. The cyclic voltammetry and electrochemical impedance spectra analysis confirmed that GR accelerated the electron transfer from the cathode surface to TCAA. With the applied cathode potential of -1.2 V (vs SCE), 95.3% of TCAA (500 μg/L) was removed within 20 min at pH 6.8. TCAA dechlorination at the Cu foam electrode was enhanced at acidic pH, while a slight pH effect was observed at the GR-Cu foam electrode with a significant inhibition for Cu leaching. The electrocatalytic dechlorination of TCAA was accomplished via a combined stepwise and concerted pathway on both electrodes, whereas the concerted pathway was efficiently promoted on the GR-Cu foam electrode. The direct reduction by electrons was responsible for TCAA dechlorination at Cu foam electrode, while at GR-Cu foam electrode, the surface-adsorbed atomic H* also contributed to TCAA dechlorination owing to the chemical storage of hydrogen in the GR structure. Finally, the potential applicability of GR-Cu foam was revealed by its stability in the electrocatalytic dechlorination over 25 cycles.

  19. Ice-templated Self-assembly of VOPO4-Graphene Nanocomposites for Vertically Porous 3D Supercapacitor Electrodes

    NASA Astrophysics Data System (ADS)

    Lee, Kwang Hoon; Lee, Young-Woo; Lee, Seung Woo; Ha, Jeong Sook; Lee, Sang-Soo; Son, Jeong Gon

    2015-09-01

    A simple ice-templated self-assembly process is used to prepare a three-dimensional (3D) and vertically porous nanocomposite of layered vanadium phosphates (VOPO4) and graphene nanosheets with high surface area and high electrical conductivity. The resulting 3D VOPO4-graphene nanocomposite has a much higher capacitance of 527.9 F g-1 at a current density of 0.5 A g-1, compared with ~247 F g-1 of simple 3D VOPO4, with solid cycling stability. The enhanced pseudocapacitive behavior mainly originates from vertically porous structures from directionally grown ice crystals and simultaneously inducing radial segregation and forming inter-stacked structures of VOPO4-graphene nanosheets. This VOPO4-graphene nanocomposite electrode exhibits high surface area, vertically porous structure to the separator, structural stability from interstacked structure and high electrical conductivity, which would provide the short diffusion paths of electrolyte ions and fast transportation of charges within the conductive frameworks. In addition, an asymmetric supercapacitor (ASC) is fabricated by using vertically porous VOPO4-graphene as the positive electrode and vertically porous 3D graphene as the negative electrode; it exhibits a wide cell voltage of 1.6 V and a largely enhanced energy density of 108 Wh kg-1.

  20. Ice-templated Self-assembly of VOPO4–Graphene Nanocomposites for Vertically Porous 3D Supercapacitor Electrodes

    PubMed Central

    Lee, Kwang Hoon; Lee, Young-Woo; Lee, Seung Woo; Ha, Jeong Sook; Lee, Sang-Soo; Son, Jeong Gon

    2015-01-01

    A simple ice-templated self-assembly process is used to prepare a three-dimensional (3D) and vertically porous nanocomposite of layered vanadium phosphates (VOPO4) and graphene nanosheets with high surface area and high electrical conductivity. The resulting 3D VOPO4–graphene nanocomposite has a much higher capacitance of 527.9 F g−1 at a current density of 0.5 A g−1, compared with ~247 F g−1 of simple 3D VOPO4, with solid cycling stability. The enhanced pseudocapacitive behavior mainly originates from vertically porous structures from directionally grown ice crystals and simultaneously inducing radial segregation and forming inter-stacked structures of VOPO4–graphene nanosheets. This VOPO4–graphene nanocomposite electrode exhibits high surface area, vertically porous structure to the separator, structural stability from interstacked structure and high electrical conductivity, which would provide the short diffusion paths of electrolyte ions and fast transportation of charges within the conductive frameworks. In addition, an asymmetric supercapacitor (ASC) is fabricated by using vertically porous VOPO4–graphene as the positive electrode and vertically porous 3D graphene as the negative electrode; it exhibits a wide cell voltage of 1.6 V and a largely enhanced energy density of 108 Wh kg−1. PMID:26333591

  1. In situ growth of manganese oxide on 3D graphene by a reverse microemulsion method for supercapacitors

    NASA Astrophysics Data System (ADS)

    Wei, Bing; Wang, Lidong; Wang, Yang; Yuan, Yinan; Miao, Qinghua; Yang, Ziyue; Fei, Weidong

    2016-03-01

    In this study, a new, effective strategy is reported for the fabrication of composites using manganese oxide (MnO2) grown in situ on three-dimensional (3D) graphene by the reverse microemulsion (water-in-oil) method. A uniform coating of nanoscale MnO2 layers can be observed on the internal surface of 3D graphene, which could benefit rapid ionic and electronic transport. The electrochemical performance of the MnO2/3D graphene composites is optimized by the control of the composite structure and mass loading of MnO2. The MnO2/3D graphene composite thus prepared exhibits a significantly high specific capacitance of 659.7 F g-1 at 0.3 A g-1 and an excellent retention life of 106% after 1000 cycles. The facile synthesis and excellent electrochemical performance of the MnO2/3D graphene composites indicate that the developed method demonstrates potential applications for the fabrication of novel electrode materials for use in energy storage devices.

  2. Controlled 3D Assembly of Graphene Sheets to Build Conductive, Chemically Selective and Shape-Responsive Materials.

    PubMed

    Woltornist, Steven J; Varghese, Deepthi; Massucci, Daniel; Cao, Zhen; Dobrynin, Andrey V; Adamson, Douglas H

    2017-03-06

    Driven by the surface activity of graphene, electrically conductive elastomeric foams have been synthesized by the controlled reassembly of graphene sheets; from their initial stacked morphology, as found in graphite, to a percolating network of exfoliated sheets, defining hollow spheres. This network creates a template for the formation of composite foams, whose swelling behavior is sensitive to the composition of the solvent, and whose electrical resistance is sensitive to physical deformation. The self-assembly of graphene sheets is driven thermodynamically, as graphite is found to act as a 2D surfactant and is spread at high-energy interfaces. This spreading, or exfoliation, of graphite at an oil/water interface stabilizes water-in-oil emulsions, without the need for added surfactants or chemical modification of the graphene. Using a monomer such as butyl acrylate for the emulsion's oil phase, elastomeric foams are created by polymerizing the continuous oil phase. Removal of the aqueous phase then results in robust, conductive, porous, and inexpensive composites, with potential applications in energy storage, filtration, and sensing.

  3. Boosting Power Density of Microbial Fuel Cells with 3D Nitrogen-Doped Graphene Aerogel Electrode.

    PubMed

    Yang, Yang; Liu, Tianyu; Zhu, Xun; Zhang, Feng; Ye, Dingding; Liao, Qiang; Li, Yat

    2016-08-01

    A 3D nitrogen-doped graphene aerogel (N-GA) as an anode material for microbial fuel cells (MFCs) is reported. Electron microscopy images reveal that the N-GA possesses hierarchical porous structure that allows efficient diffusion of both bacterial cells and electron mediators in the interior space of 3D electrode, and thus, the colonization of bacterial communities. Electrochemical impedance spectroscopic measurements further show that nitrogen doping considerably reduces the charge transfer resistance and internal resistance of GA, which helps to enhance the MFC power density. Importantly, the dual-chamber milliliter-scale MFC with N-GA anode yields an outstanding volumetric power density of 225 ± 12 W m(-3) normalized to the total volume of the anodic chamber (750 ± 40 W m(-3) normalized to the volume of the anode). These power densities are the highest values report for milliliter-scale MFCs with similar chamber size (25 mL) under the similar measurement conditions. The 3D N-GA electrode shows great promise for improving the power generation of MFC devices.

  4. A 3D Chemically Modified Graphene Hydrogel for Fast, Highly Sensitive, and Selective Gas Sensor

    PubMed Central

    Wu, Jin; Tao, Kai; Guo, Yuanyuan; Li, Zhong; Wang, Xiaotian; Luo, Zhongzhen; Du, Chunlei; Chen, Di; Norford, Leslie K.

    2016-01-01

    Reduced graphene oxide (RGO) has proved to be a promising candidate in high‐performance gas sensing in ambient conditions. However, trace detection of different kinds of gases with simultaneously high sensitivity and selectivity is challenging. Here, a chemiresistor‐type sensor based on 3D sulfonated RGO hydrogel (S‐RGOH) is reported, which can detect a variety of important gases with high sensitivity, boosted selectivity, fast response, and good reversibility. The NaHSO3 functionalized RGOH displays remarkable 118.6 and 58.9 times higher responses to NO2 and NH3, respectively, compared with its unmodified RGOH counterpart. In addition, the S‐RGOH sensor is highly responsive to volatile organic compounds. More importantly, the characteristic patterns on the linearly fitted response–temperature curves are employed to distinguish various gases for the first time. The temperature of the sensor is elevated rapidly by an imbedded microheater with little power consumption. The 3D S‐RGOH is characterized and the sensing mechanisms are proposed. This work gains new insights into boosting the sensitivity of detecting various gases by combining chemical modification and 3D structural engineering of RGO, and improving the selectivity of gas sensing by employing temperature dependent response characteristics of RGO for different gases. PMID:28331786

  5. High-Strength Stereolithographic 3D Printed Nanocomposites: Graphene Oxide Metastability.

    PubMed

    Manapat, Jill Z; Mangadlao, Joey Dacula; Tiu, Brylee David Buada; Tritchler, Grace C; Advincula, Rigoberto C

    2017-03-22

    The weak thermomechanical properties of commercial 3D printing plastics have limited the technology's application mainly to rapid prototyping. In this report, we demonstrate a simple approach that takes advantage of the metastable, temperature-dependent structure of graphene oxide (GO) to enhance the mechanical properties of conventional 3D-printed resins produced by stereolithography (SLA). A commercially available SLA resin was reinforced with minimal amounts of GO nanofillers and thermally annealed at 50 and 100 °C for 12 h. Tensile tests revealed increasing strength and modulus at an annealing temperature of 100 °C, with the highest tensile strength increase recorded at 673.6% (for 1 wt % GO). Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) also showed increasing thermal stability with increasing annealing temperature. The drastic enhancement in mechanical properties, which is seen to this degree in 3D-printed samples reported in literature, is attributed to the metastable structure of GO, polymer-nanofiller cross-linking via acid-catalyzed esterification, and removal of intercalated water, thus improving filler-matrix interaction as evidenced by spectroscopy and microscopy analyses.

  6. Boosting Power Density of Microbial Fuel Cells with 3D Nitrogen‐Doped Graphene Aerogel Electrode

    PubMed Central

    Yang, Yang; Liu, Tianyu; Zhang, Feng; Ye, Dingding; Liao, Qiang

    2016-01-01

    A 3D nitrogen‐doped graphene aerogel (N‐GA) as an anode material for microbial fuel cells (MFCs) is reported. Electron microscopy images reveal that the N‐GA possesses hierarchical porous structure that allows efficient diffusion of both bacterial cells and electron mediators in the interior space of 3D electrode, and thus, the colonization of bacterial communities. Electrochemical impedance spectroscopic measurements further show that nitrogen doping considerably reduces the charge transfer resistance and internal resistance of GA, which helps to enhance the MFC power density. Importantly, the dual‐chamber milliliter‐scale MFC with N‐GA anode yields an outstanding volumetric power density of 225 ± 12 W m−3 normalized to the total volume of the anodic chamber (750 ± 40 W m−3 normalized to the volume of the anode). These power densities are the highest values report for milliliter‐scale MFCs with similar chamber size (25 mL) under the similar measurement conditions. The 3D N‐GA electrode shows great promise for improving the power generation of MFC devices. PMID:27818911

  7. Multifunctional Polymer-Based Graphene Foams with Buckled Structure and Negative Poisson’s Ratio

    PubMed Central

    Dai, Zhaohe; Weng, Chuanxin; Liu, Luqi; Hou, Yuan; Zhao, Xuanliang; Kuang, Jun; Shi, Jidong; Wei, Yueguang; Lou, Jun; Zhang, Zhong

    2016-01-01

    In this study, we report the polymer-based graphene foams through combination of bottom-up assembly and simple triaxially buckled structure design. The resulting polymer-based graphene foams not only effectively transfer the functional properties of graphene, but also exhibit novel negative Poisson’s ratio (NPR) behaviors due to the presence of buckled structure. Our results show that after the introduction of buckled structure, improvement in stretchability, toughness, flexibility, energy absorbing ability, hydrophobicity, conductivity, piezoresistive sensitivity and crack resistance could be achieved simultaneously. The combination of mechanical properties, multifunctional performance and unusual deformation behavior would lead to the use of our polymer-based graphene foams for a variety of novel applications in future such as stretchable capacitors or conductors, sensors and oil/water separators and so on. PMID:27608928

  8. Multifunctional Polymer-Based Graphene Foams with Buckled Structure and Negative Poisson’s Ratio

    NASA Astrophysics Data System (ADS)

    Dai, Zhaohe; Weng, Chuanxin; Liu, Luqi; Hou, Yuan; Zhao, Xuanliang; Kuang, Jun; Shi, Jidong; Wei, Yueguang; Lou, Jun; Zhang, Zhong

    2016-09-01

    In this study, we report the polymer-based graphene foams through combination of bottom-up assembly and simple triaxially buckled structure design. The resulting polymer-based graphene foams not only effectively transfer the functional properties of graphene, but also exhibit novel negative Poisson’s ratio (NPR) behaviors due to the presence of buckled structure. Our results show that after the introduction of buckled structure, improvement in stretchability, toughness, flexibility, energy absorbing ability, hydrophobicity, conductivity, piezoresistive sensitivity and crack resistance could be achieved simultaneously. The combination of mechanical properties, multifunctional performance and unusual deformation behavior would lead to the use of our polymer-based graphene foams for a variety of novel applications in future such as stretchable capacitors or conductors, sensors and oil/water separators and so on.

  9. Flexible 3D Nanoporous Graphene for Desalination and Bio-decontamination of Brackish Water via Asymmetric Capacitive Deionization.

    PubMed

    El-Deen, Ahmed G; Boom, Remko M; Kim, Hak Yong; Duan, Hongwei; Chan-Park, Mary B; Choi, Jae-Hwan

    2016-09-28

    Nanoporous graphene based materials are a promising nanostructured carbon for energy storage and electrosorption applications. We present a novel and facile strategy for fabrication of asymmetrically functionalized microporous activated graphene electrodes for high performance capacitive desalination and disinfection of brackish water. Briefly, thiocarbohydrazide coated silica nanoparticles intercalated graphene sheets are used as a sacrificial material for creating mesoporous graphene followed by alkaline activation process. This fabrication procedure meets the ideal desalination pore diameter with ultrahigh specific surface area ∼ 2680 m(2) g(-1) of activated 3D graphene based micropores. The obtained activated graphene electrode is modified by carboxymethyl cellulose as negative charge (COO(-2)) and disinfectant quaternary ammonium cellulose with positively charged polyatomic ions of the structure (NR4(+)). Our novel asymmetric coated microporous activated 3D graphene employs nontoxic water-soluble binder which increases the surface wettability and decreases the interfacial resistance and moreover improves the electrode flexibility compared with organic binders. The desalination performance of the fabricated electrodes was evaluated by carrying out single pass mode experiment under various cell potentials with symmetric and asymmetric cells. The asymmetric charge coated microporous activated graphene exhibits exceptional electrosorption capacity of 18.43 mg g(-1) at a flow rate of 20 mL min(-1) upon applied cell potential of 1.4 V with initial NaCl concentration of 300 mg L(-1), high charge efficiency, excellent recyclability, and, moreover, good antibacterial behavior. The present strategy provides a new avenue for producing ultrapure water via green capacitive deionization technology.

  10. Vanadium nanobelts coated nickel foam 3D bifunctional electrode with excellent catalytic activity and stability for water electrolysis

    NASA Astrophysics Data System (ADS)

    Yu, Yu; Li, Pei; Wang, Xiaofang; Gao, Wenyu; Shen, Zongxu; Zhu, Yanan; Yang, Shuliang; Song, Weiguo; Ding, Kejian

    2016-05-01

    Pursuit of highly active, stable and low-cost electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is the key point for large-scale water splitting. A vanadium nanobelts coating on a nickel foam (V/NF) is proposed as an excellent 3D bifunctional electrode for water electrolysis here, which exhibits high activities with overpotentials of 292 and 176 mV at 10 mA cm-2 for OER and HER, respectively. When employed as a bifunctional electrocatalyst in an alkaline water electrolyzer, a cell voltage of 1.80 V was required to achieve 20 mA cm-2 with a slight increase during a 24 h durability test. The existence of the appropriate amount of nitrogen and oxygen elements in the surface region of vanadium nanobelts is regarded to be responsible for the electrocatalytic activity.Pursuit of highly active, stable and low-cost electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is the key point for large-scale water splitting. A vanadium nanobelts coating on a nickel foam (V/NF) is proposed as an excellent 3D bifunctional electrode for water electrolysis here, which exhibits high activities with overpotentials of 292 and 176 mV at 10 mA cm-2 for OER and HER, respectively. When employed as a bifunctional electrocatalyst in an alkaline water electrolyzer, a cell voltage of 1.80 V was required to achieve 20 mA cm-2 with a slight increase during a 24 h durability test. The existence of the appropriate amount of nitrogen and oxygen elements in the surface region of vanadium nanobelts is regarded to be responsible for the electrocatalytic activity. Electronic supplementary information (ESI) available: More SEM, TEM images, XRD patterns, LSV curves, XPS spectra. See DOI: 10.1039/c6nr02395a

  11. Nitrogen-doped 3D macroporous graphene frameworks as anode for high performance lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Liu, Xiaowu; Wu, Ying; Yang, Zhenzhong; Pan, Fusen; Zhong, Xiongwu; Wang, Jiaqing; Gu, Lin; Yu, Yan

    2015-10-01

    Nitrogen-doped 3D graphene frameworks (N-3D GFs) were synthesized by a facile two-step method: Polystyrene (PS) encapsulated in graphene oxide (GO) composites (denoted as PS@GO) are first synthesized, followed by a post-thermal annealing in ammonia step to get N-doped 3D GFs. The resulting N-3D GFs inherit the advantages of graphene, which possesses high electrical conductivity and high specific surface area. Furthermore, the well-defined 3D interconnected structure can facilitate the access of the electrolyte to the electrode surface, thus shortening the diffusion length of both Li+/e-, keeping the overall electrode highly conductive and active in lithium storage. Simultaneously, the in-situ formation of pyridinic N and pyrrolic N in 3D GFs provide high electronic conductivity and structure stability for lithium storage. The designed N-3D GFs electrode delivers a high specific capacity of 1094 mAhg-1 after 100 cycles at 200 mAg-1 and superior rate capability (691 mAhg-1 after 500 cycles at 1000 mAg-1) when used as anode for LIBs. We believe that such an inherently inexpensive, scalable, facile method can significantly increase the feasibility of building high performance energy storage system.

  12. Nickel/cobalt oxide-decorated 3D graphene nanocomposite electrode for enhanced electrochemical detection of urea.

    PubMed

    Nguyen, Nhi Sa; Das, Gautam; Yoon, Hyon Hee

    2016-03-15

    A NiCo2O4 bimetallic electro-catalyst was synthesized on three-dimensional graphene (3D graphene) for the non-enzymatic detection of urea. The structural and morphological properties of the NiCo2O4/3D graphene nanocomposite were characterized by X-ray diffraction, Raman spectroscopy, and scanning electron microscopy. The NiCo2O4/3D graphene was deposited on an indium tin oxide (ITO) glass to fabricate a highly sensitive urea sensor. The electrochemical properties of the prepared electrode were studied by cyclic voltammetry. A high sensitivity of 166 μAmM(-)(1)cm(-)(2) was obtained for the NiCo2O4/3D graphene/ITO sensor. The sensor exhibited a linear range of 0.06-0.30 mM (R(2)=0.998) and a fast response time of approximately 1.0 s with a detection limit of 5.0 µM. Additionally, the sensor exhibited high stability with a sensitivity decrease of only 5.5% after four months of storage in ambient conditions. The urea sensor demonstrates feasibility for urea analysis in urine samples.

  13. Subacute Tissue Response to 3D Graphene Oxide Scaffolds Implanted in the Injured Rat Spinal Cord.

    PubMed

    López-Dolado, Elisa; González-Mayorga, Ankor; Portolés, María Teresa; Feito, María José; Ferrer, María Luisa; Del Monte, Francisco; Gutiérrez, María Concepción; Serrano, María Concepción

    2015-08-26

    The increasing prevalence and high sanitary costs of lesions affecting the central nervous system (CNS) at the spinal cord are encouraging experts in different fields to explore new avenues for neural repair. In this context, graphene and its derivatives are attracting significant attention, although their toxicity and performance in the CNS in vivo remains unclear. Here, the subacute tissue response to 3D flexible and porous scaffolds composed of partially reduced graphene oxide is investigated when implanted in the injured rat spinal cord. The interest of these structures as potentially useful platforms for CNS regeneration mainly relies on their mechanical compliance with neural tissues, adequate biocompatibility with neural cells in vitro and versatility to carry topographical and biological guidance cues. Early tissue responses are thoroughly investigated locally (spinal cord at C6 level) and in the major organs (i.e., kidney, liver, lung, and spleen). The absence of local and systemic toxic responses, along with the positive signs found at the lesion site (e.g., filler effect, soft interface for no additional scaring, preservation of cell populations at the perilesional area, presence of M2 macrophages), encourages further investigation of these materials as promising components of more efficient material-based platforms for CNS repair.

  14. 3D nanostructured inkjet printed graphene via UV-pulsed laser irradiation enables paper-based electronics and electrochemical devices.

    PubMed

    Das, Suprem R; Nian, Qiong; Cargill, Allison A; Hondred, John A; Ding, Shaowei; Saei, Mojib; Cheng, Gary J; Claussen, Jonathan C

    2016-09-21

    Emerging research on printed and flexible graphene-based electronics is beginning to show tremendous promise for a wide variety of fields including wearable sensors and thin film transistors. However, post-print annealing/reduction processes that are necessary to increase the electrical conductivity of the printed graphene degrade sensitive substrates (e.g., paper) and are whole substrate processes that are unable to selectively anneal/reduce only the printed graphene-leaving sensitive device components exposed to damaging heat or chemicals. Herein a pulsed laser process is introduced that can selectively irradiate inkjet printed reduced graphene oxide (RGO) and subsequently improve the electrical conductivity (Rsheet∼0.7 kΩ□(-1)) of printed graphene above previously published reports. Furthermore, the laser process is capable of developing 3D petal-like graphene nanostructures from 2D planar printed graphene. These visible morphological changes display favorable electrochemical sensing characteristics-ferricyanide cyclic voltammetry with a redox peak separation (ΔEp) ≈ 0.7 V as well as hydrogen peroxide (H2O2) amperometry with a sensitivity of 3.32 μA mM(-1) and a response time of <5 s. Thus this work paves the way for not only paper-based electronics with graphene circuits, it enables the creation of low-cost and disposable graphene-based electrochemical electrodes for myriad applications including sensors, biosensors, fuel cells, and theranostic devices.

  15. Facile fabrication of three-dimensional graphene foam/poly(dimethylsiloxane) composites and their potential application as strain sensor.

    PubMed

    Xu, Rongqing; Lu, Yunqing; Jiang, Chunhui; Chen, Jing; Mao, Peng; Gao, Guanghua; Zhang, Labao; Wu, Shan

    2014-08-27

    A three-dimensional (3D) graphene foam (GF)/poly(dimethylsiloxane) (PDMS) composite was fabricated by infiltrating PDMS into 3D GF, which was synthesized by chemical vapor deposition (CVD) with nickel foam as template. The electrical properties of the GF/PDMS composite under bending stress were investigated, indicating the resistance of the GF/PDMS composite was increased with the bending curvature. To improve the bending sensitivity of the GF/PDMS composite, a thin layer of poly(ethylene terephthalate) (PET) was introduced as substrate to form double-layer GF/PDMS-PET composite, whose measurements showed that the resistance of the GF/PDMS-PET composite was still increased when bended to the side of PET, whereas its resistance would be decreased when bended to the side of GF. For both cases, the absolute value of the relative variation of electrical resistance was increased with the bending curvature. More importantly, the relative variation of electrical resistance for double-layer GF/PDMS-PET composite can be up to six times higher than single-layer GF/PDMS composite for the same bending curvature. These observations were further supported by the principle of mechanics of material. The 3D GF/PDMS-PET composite also has higher flexibility and environment stability and can be utilized as a strain sensor with high sensitivity, which can find important applications in real-time monitoring of buildings, such as a bridge, dam, and high-speed railway.

  16. Mesoporous NiCo2O4 Nanoplates on Three-Dimensional Graphene Foam as an Efficient Electrocatalyst for the Oxygen Reduction Reaction.

    PubMed

    Tong, Xili; Chen, Shuai; Guo, Congxiu; Xia, Xinhui; Guo, Xiang-Yun

    2016-01-21

    Catalysts for the oxygen reduction reaction (ORR) are highly important in fuel cells and metal-air batteries. Cheap ORR catalysts with ultrahigh electrochemical activity, selectivity, and stability are extremely desirable but still remain challenging. Herein, mesoporous NiCo2O4 nanoplate (NP) arrays on three-dimensional (3D) graphene foam are shown to be a highly economical ORR catalyst. This mesoporous mixed-valence oxide can provide more electrocatalytic active sites with increased accessible surface area. In addition, graphene-foam-supported NiCo2O4 NP arrays have a 3D hierarchical porous structure, which is of great benefit to ion diffusion and electron transfer. As a result, the mesoporous NiCo2O4 NP arrays/graphene foam catalyst exhibits outstanding ORR performance with the four-electron reduction of O2 to H2O in alkaline media. Furthermore, the mesoporous catalyst shows enhanced electrocatalytic activity with a half-wave potential of 0.86 V vs RHE and better stability compared with a commercial Pt/C catalyst.

  17. Pillared Graphene: A New 3-D Innovative Network Nanostructure Augments Hydrogen Storage

    NASA Astrophysics Data System (ADS)

    Georgios, Dimitrakakis K.; Emmanuel, Tylianakis; George, Froudakis E.

    2009-08-01

    Nowadays, people have turned into finding an alternative power source for everyday applications. One of the most promising energy fuels is hydrogen. It can be used as an energy carrier at small portable devices (e.g. laptops and/or cell phones) up to larger, like cars. Hydrogen is considered as the perfect fuel. It can be burnt in combustion engines and the only by-product is water. For hydrogen-powered vehicles a big liming factor is the gas tank and is the reason for not using widely hydrogen in automobile applications. According to United States' Department of Energy (D.O.E.) the target for reversible hydrogen storage in mobile applications is 6% wt. and 45 gr. H2/L and these should be met by 2010. After their synthesis Carbon Nanotubes (CNTs) were considered as ideal candidates for hydrogen storage especially after some initially incorrect but invitingly results. As it was proven later, pristine carbon nanotubes cannot achieve D.O.E.'s targets in ambient conditions of pressure and temperature. Therefore, a way to increase their hydrogen storage capacity should be found. An attempt was done by doping CNTs with alkali metal atoms. Although the results were promising, even that increment was not enough. Consequently, new architectures were suggested as materials that could potentially enhance hydrogen storage. In this work a novel three dimensional (3-D) nanoporous carbon structure called Pillared Graphene (Figure 1) is proposed for augmented hydrogen storage in ambient conditions. Pillared Graphene consists of parallel graphene sheets and CNTs that act like pillars and support the graphene sheets. The entire structure (Figure 1) can be resembled like a building in its early stages of construction, where the floors are represented by graphene sheets and the pillars are the CNTs. As shown in Figure 1, CNTs do not penetrate the structure from top to bottom. Instead, they alternately go up and down, so that on the same plane do not exist two neighboring CNTs with the

  18. Direct fabrication of 3D graphene on nanoporous anodic alumina by plasma-enhanced chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Zhan, Hualin; Garrett, David J.; Apollo, Nicholas V.; Ganesan, Kumaravelu; Lau, Desmond; Prawer, Steven; Cervenka, Jiri

    2016-01-01

    High surface area electrode materials are of interest for a wide range of potential applications such as super-capacitors and electrochemical cells. This paper describes a fabrication method of three-dimensional (3D) graphene conformally coated on nanoporous insulating substrate with uniform nanopore size. 3D graphene films were formed by controlled graphitization of diamond-like amorphous carbon precursor films, deposited by plasma-enhanced chemical vapour deposition (PECVD). Plasma-assisted graphitization was found to produce better quality graphene than a simple thermal graphitization process. The resulting 3D graphene/amorphous carbon/alumina structure has a very high surface area, good electrical conductivity and exhibits excellent chemically stability, providing a good material platform for electrochemical applications. Consequently very large electrochemical capacitance values, as high as 2.1 mF for a sample of 10 mm3, were achieved. The electrochemical capacitance of the material exhibits a dependence on bias voltage, a phenomenon observed by other groups when studying graphene quantum capacitance. The plasma-assisted graphitization, which dominates the graphitization process, is analyzed and discussed in detail.

  19. Direct fabrication of 3D graphene on nanoporous anodic alumina by plasma-enhanced chemical vapor deposition

    PubMed Central

    Zhan, Hualin; Garrett, David J.; Apollo, Nicholas V.; Ganesan, Kumaravelu; Lau, Desmond; Prawer, Steven; Cervenka, Jiri

    2016-01-01

    High surface area electrode materials are of interest for a wide range of potential applications such as super-capacitors and electrochemical cells. This paper describes a fabrication method of three-dimensional (3D) graphene conformally coated on nanoporous insulating substrate with uniform nanopore size. 3D graphene films were formed by controlled graphitization of diamond-like amorphous carbon precursor films, deposited by plasma-enhanced chemical vapour deposition (PECVD). Plasma-assisted graphitization was found to produce better quality graphene than a simple thermal graphitization process. The resulting 3D graphene/amorphous carbon/alumina structure has a very high surface area, good electrical conductivity and exhibits excellent chemically stability, providing a good material platform for electrochemical applications. Consequently very large electrochemical capacitance values, as high as 2.1 mF for a sample of 10 mm3, were achieved. The electrochemical capacitance of the material exhibits a dependence on bias voltage, a phenomenon observed by other groups when studying graphene quantum capacitance. The plasma-assisted graphitization, which dominates the graphitization process, is analyzed and discussed in detail. PMID:26805546

  20. Thermal conductivity enhancement of laser induced graphene foam upon P3HT infiltration

    NASA Astrophysics Data System (ADS)

    Smith, M. K.; Luong, D. X.; Bougher, T. L.; Kalaitzidou, K.; Tour, J. M.; Cola, B. A.

    2016-12-01

    Significant research has been dedicated to the exploration of high thermal conductivity polymer composite materials with conductive filler particles for use in heat transfer applications. However, poor particle dispersibility and interfacial phonon scattering have limited the effective composite thermal conductivity. Three-dimensional foams with high ligament thermal conductivity offer a potential solution to the two aforementioned problems but are traditionally fabricated through expensive and/or complex manufacturing methods. Here, laser induced graphene foams, fabricated through a simple and cost effective laser ablation method, are infiltrated with poly(3-hexylthiophene) in a step-wise fashion to demonstrate the impact of polymer on the thermal conductivity of the composite system. Surprisingly, the addition of polymer results in a drastic (250%) improvement in material thermal conductivity, enhancing the graphene foam's thermal conductivity from 0.68 W/m-K to 1.72 W/m-K for the fully infiltrated composite material. Graphene foam density measurements and theoretical models are utilized to estimate the effective ribbon thermal conductivity as a function of polymer filling. Here, it is proposed that the polymer solution acts as a binding material, which draws graphene ligaments together through elastocapillary coalescence and bonds these ligaments upon drying, resulting in greatly reduced contact resistance within the foam and an effective thermal conductivity improvement greater than what would be expected from the addition of polymer alone.

  1. Multi and mixed 3D-printing of graphene-hydroxyapatite hybrid materials for complex tissue engineering.

    PubMed

    Jakus, Adam E; Shah, Ramille N

    2017-01-01

    With the emergence of three-dimensional (3D)-printing (3DP) as a vital tool in tissue engineering and medicine, there is an ever growing need to develop new biomaterials that can be 3D-printed and also emulate the compositional, structural, and functional complexities of human tissues and organs. In this work, we probe the 3D-printable biomaterials spectrum by combining two recently established functional 3D-printable particle-laden biomaterial inks: one that contains hydroxyapatite microspheres (hyperelastic bone, HB) and another that contains graphene nanoflakes (3D-graphene, 3DG). We demonstrate that not only can these distinct, osteogenic, and neurogenic inks be co-3D-printed to create complex, multimaterial constructs, but that composite inks of HB and 3DG can also be synthesized. Specifically, the printability, microstructural, mechanical, electrical, and biological properties of a hybrid material comprised of 1:1 HA:graphene by volume is investigated. The resulting HB-3DG hybrid exhibits mixed characteristics of the two distinct systems, while maintaining 3D-printability, electrical conductivity, and flexibility. In vitro assessment of HB-3DG using mesenchymal stem cells demonstrates the hybrid material supports cell viability and proliferation, as well as significantly upregulates both osteogenic and neurogenic gene expression over 14 days. This work ultimately demonstrates a significant step forward towards being able to 3D-print graded, multicompositional, and multifunctional constructs from hybrid inks for complex composite tissue engineering. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 274-283, 2017.

  2. Graphene oxide/chitin nanofibril composite foams as column adsorbents for aqueous pollutants.

    PubMed

    Ma, Zhongshi; Liu, Dagang; Zhu, Yi; Li, Zehui; Li, Zhenxuan; Tian, Huafeng; Liu, Haiqing

    2016-06-25

    A novel graphene oxide/chitin nanofibrils (GO-CNF) composite foam as a column adsorbent was prepared for aqueous contaminant disposal. The structures, morphologies and properties of composite foams supported by nanofibrils were characterized. As a special case, the adsorption of methylene blue (MB) on GO-CNF was investigated regarding the static adsorption and column adsorption-desorption tests. Results from equilibrium adsorption isotherms indicated that the adsorption behavior was well-fitted to Langmuir model. The composite foams reinforced by CNF were dimensionally stable during the column adsorption process and could be reused after elution. The removal efficiency of MB was still nearly 90% after 3 cycles. Furthermore, other inorganic or organic pollutants adsorbed by composite foams were also explored. Therefore, this novel composite foam with remarkable properties such as dimensional stability, universal adsorbent for cationic pollutants, high adsorption capacity, and ease of regeneration was a desirable adsorbent in the future practical application of water pollutant treatment.

  3. Self-Assembled 3D Foam-Like NiCo2O4 as Efficient Catalyst for Lithium Oxygen Batteries.

    PubMed

    Liu, Lili; Wang, Jun; Hou, Yuyang; Chen, Jun; Liu, Hua-Kun; Wang, Jiazhao; Wu, Yuping

    2016-02-03

    A self-assembled 3D foam-like NiCo2O4 catalyst has been synthesized via a simple and environmental friendly approach, wherein starch acts as the template to form the unique 3D architecture. Interestingly, when employed as a cathode for lithium oxygen batteries, it demonstrates superior bifunctional electrocatalytic activities toward both the oxygen reduction reaction and the oxygen evolution reaction, with a relatively high round-trip efficiency of 70% and high discharge capacity of 10 137 mAh g(-1) at a current density of 200 mA g(-1), which is much higher than those in previously reported results. Meanwhile, rotating disk electrode measurements in both aqueous and nonaqueous electrolyte are also employed to confirm the electrocatalytic activity for the first time. This excellent performance is attributed to the synergistic benefits of the unique 3D foam-like structure and the intrinsically high catalytic activity of NiCo2O4 .

  4. Nanoporous Ni(OH)2 thin film on 3D Ultrathin-graphite foam for asymmetric supercapacitor.

    PubMed

    Ji, Junyi; Zhang, Li Li; Ji, Hengxing; Li, Yang; Zhao, Xin; Bai, Xin; Fan, Xiaobin; Zhang, Fengbao; Ruoff, Rodney S

    2013-07-23

    Nanoporous nickel hydroxide (Ni(OH)2) thin film was grown on the surface of ultrathin-graphite foam (UGF) via a hydrothermal reaction. The resulting free-standing Ni(OH)2/UGF composite was used as the electrode in a supercapacitor without the need for addition of either binder or metal-based current collector. The highly conductive 3D UGF network facilitates electron transport and the porous Ni(OH)2 thin film structure shortens ion diffusion paths and facilitates the rapid migration of electrolyte ions. An asymmetric supercapacitor was also made and studied with Ni(OH)2/UGF as the positive electrode and activated microwave exfoliated graphite oxide ('a-MEGO') as the negative electrode. The highest power density of the fully packaged asymmetric cell (44.0 kW/kg) was much higher (2-27 times higher), while the energy density was comparable to or higher, than high-end commercially available supercapacitors. This asymmetric supercapacitor had a capacitance retention of 63.2% after 10,000 cycles.

  5. Polyaniline nanofiber sponge filled graphene foam as high gravimetric and volumetric capacitance electrode

    NASA Astrophysics Data System (ADS)

    Pedrós, J.; Boscá, A.; Martínez, J.; Ruiz-Gómez, S.; Pérez, L.; Barranco, V.; Calle, F.

    2016-06-01

    A 3D hierarchical porous composite structure is developed via the controlled electrodeposition of a polyaniline nanofiber sponge (PANI-NFS) that fills the pores of a chemical vapor deposited graphene foam (GF). The PANI-NFS/GF composite combines the efficient electronic transport in the GF scaffold (with 100-500 μm pore size) with the rapid diffusion of the electrolyte ions into the high-specific-surface-area and densely-packed PANI-NFS (with 100-500 nm pore size). The factor of 1000 in the pore hierarchy and the synergy between the materials, that form a supercapacitor composite electrode with an integrated extended current collector, lead to both very high gravimetric and volumetric capacitances. In particular, values of 1474 F g-1 and 86 F cm-3 for a GF filling factor of 11% (leading to an estimated value of 782 F cm-3 for 100%), respectively, are obtained at a current density of 0.47 A g-1. Moreover, the composite electrode presents a capacitance retention of 83% after 15000 cycles. This excellent behavior makes the PANI-NFS/GF composite electrodes very attractive for high-performance supercapacitors.

  6. A theory of electrical conductivity, dielectric constant, and electromagnetic interference shielding for lightweight graphene composite foams

    NASA Astrophysics Data System (ADS)

    Xia, Xiaodong; Wang, Yang; Zhong, Zheng; Weng, George J.

    2016-08-01

    This work was driven by the need to understand the electromagnetic interference (EMI) shielding effectiveness (SE) of light weight, flexible, and high performance graphene composite foams, but as EMI SE of a material depends on its electrical conductivity, dielectric permittivity, and magnetic permeability, the investigation of these three properties also became a priority. In this paper, we first present a continuum theory to determine these three electromagnetic properties, and then use the obtained properties to evaluate the EMI SE of the foam. A two-scale composite model is conceived to evaluate these three properties, with the large one being the skeleton-void composite and the small one being the graphene-polymer composite that serves as the skeleton of the foam. To evaluate the properties of the skeleton, the effective-medium approach is taken as the starting point. Subsequently, the effect of an imperfect interface and the contributions of electron tunneling to the interfacial conductivity and Maxwell-Wagner-Sillars polarization mechanism to the dielectric constant are also implemented. The derived skeleton properties are then utilized on the large scale to determine the three properties of the composite foam at a given porosity. Then a uniform plane electromagnetic wave is considered to evaluate the EMI SE of the foam. It is demonstrated that the electrical conductivity, dielectric constant, and EMI SE of the foam calculated from the developed theory are in general agreement with the reported experimental data of graphene/PDMS composite foams. The theory is further proven to be valid for the EMI SE of solid graphene/epoxy and solid carbon nanotube/epoxy nanocomposites. It is also shown that, among the three electromagnetic properties, electrical conductivity has the strongest influence on the EMI shielding effectiveness.

  7. Mobility controlled linear magnetoresistance with 3D anisotropy in a layered graphene pallet

    NASA Astrophysics Data System (ADS)

    Zhang, Qiang; Li, Peng; He, Xin; Li, Jun; Wen, Yan; Ren, Wencai; Cheng, Hui-ming; Yang, Yang; Al-Hadeethi, Yas F.; Zhang, Xixiang

    2016-10-01

    A bulk sample of pressed graphene sheets was prepared under hydraulic pressure (~150 MPa). The cross-section of the sample demonstrates a layered structure, which leads to 3D electrical transport properties with anisotropic mobility. The electrical transport properties of the sample were measured over a wide temperature (2-400 K) and magnetic field (-140 ~\\text{kOe}≤slant H≤slant 140 ~\\text{kOe} ) range. The magnetoresistance measured at a fixed temperature can be described by R≤ft(H,θ \\right)=R≤ft({{\\varepsilon}θ}H,0\\right) with {{\\varepsilon}θ}={≤ft({{\\cos}2}θ +{{γ-2}{{\\sin}2}θ \\right)}1/2} , where γ is the mobility anisotropy constant and θ is the angle between the normal of the sample plane and the magnetic field. The large linear magnetoresistance (up to 36.9% at 400 K and 140 kOe) observed at high fields is ascribed to a classical magnetoresistance caused by mobility fluctuation ( Δ μ ). The magnetoresistance value at 140 kOe was related to the average mobility ≤ft(< μ > \\right) because of the condition Δ μ << μ > . The carrier concentration remained constant and the temperature-dependent resistivity was proportional to the average mobility, as verified by Kohler’s rule. Anisotropic dephasing length was deduced from weak localization observed at low temperatures.

  8. Structural, electronic and magnetic properties of 3d metal trioxide clusters-doped monolayer graphene: A first-principles study

    NASA Astrophysics Data System (ADS)

    Rafique, Muhammad; Shuai, Yong; Tan, He-Ping; Hassan, Muhammad

    2017-03-01

    We present first-principles density-functional calculations for the structural, electronic and magnetic properties of monolayer graphene doped with 3d (Ti, V, Cr, Fe, Co, Mn and Ni) metal trioxide TMO3 halogen clusters. In this paper we used two approaches for 3d metal trioxide clusters (i) TMO3 halogen cluster was embedded in monolayer graphene substituting four carbon (C) atoms (ii) three C atoms were substituted by three oxygen (O) atoms in one graphene ring and TM atom was adsorbed at the hollow site of O atoms substituted graphene ring. All the impurities were tightly bonded in the graphene ring. In first case of TMO3 doped graphene layer, the bond length between Csbnd O atom was reduced and bond length between TM-O atom was increased. In case of Cr, Fe, Co and Ni atoms substitution in between the O atoms, leads to Fermi level shifting to conduction band thereby causing the Dirac cone to move into valence band, however a band gap appears at high symmetric K-point. In case of TiO3 and VO3 substitution, system exhibits semiconductor properties. Interestingly, TiO3-substituted system shows dilute magnetic semiconductor behavior with 2.00 μB magnetic moment. On the other hand, the substitution of CoO3, CrO3, FeO3 and MnO3 induced 1.015 μB, 2.347 μB, 2.084 μB and 3.584 μB magnetic moment, respectively. In second case of O atoms doped in graphene and TM atoms adsorbed at the hollow site, the O atom bulges out of graphene plane and bond length between TM-O atom is increased. After TM atoms adsorption at the O substituted graphene ring the Fermi level (EF) shifts into conduction band. In case of Cr and Ni adsorption, system displays indirect band gap semiconductor properties with 0.0 μB magnetic moment. Co adsorption exhibits dilute magnetic semiconductor behavior producing 0.916 μB magnetic moment. Fe, Mn, Ti and V adsorption introduces band gap at high symmetric K-point also inducing 1.54 μB, 0.9909 μB, 1.912 μB, and 0.98 μB magnetic moments, respectively

  9. Preparation and characterization of three dimensional graphene foam supported platinum-ruthenium bimetallic nanocatalysts for hydrogen peroxide based electrochemical biosensors.

    PubMed

    Kung, Chih-Chien; Lin, Po-Yuan; Buse, Frederick John; Xue, Yuhua; Yu, Xiong; Dai, Liming; Liu, Chung-Chiun

    2014-02-15

    The large surface, the excellent dispersion and the high degrees of sensitivity of bimetallic nanocatalysts were the attractive features of this investigation. Graphene foam (GF) was a three dimensional (3D) porous architecture consisting of extremely large surface and high conductive pathways. In this study, 3D GF was used incorporating platinum-ruthenium (PtRu) bimetallic nanoparticles as an electrochemical nanocatalyst for the detection of hydrogen peroxide (H2O2). PtRu/3D GF nanocatalyst exhibited a remarkable performance toward electrochemical oxidation of H2O2 without any additional mediator showing a high sensitivity (1023.1 µA mM(-1)cm(-2)) and a low detection limit (0.04 µM) for H2O2. Amperometric results demonstrated that GF provided a promising platform for the development of electrochemical sensors in biosensing and PtRu/3D GF nanocatalyst possessed the excellent catalytic activity toward the H2O2 detection. A small particle size and a high degree of the dispersion in obtaining of large active surface area were important for the nanocatalyst for the best H2O2 detection in biosensing. Moreover, potential interference by ascorbic acid and uric acid appeared to be negligible.

  10. Rationally designed graphene-nanotube 3D architectures with a seamless nodal junction for efficient energy conversion and storage

    PubMed Central

    Xue, Yuhua; Ding, Yong; Niu, Jianbing; Xia, Zhenhai; Roy, Ajit; Chen, Hao; Qu, Jia; Wang, Zhong Lin; Dai, Liming

    2015-01-01

    One-dimensional (1D) carbon nanotubes (CNTs) and 2D single-atomic layer graphene have superior thermal, electrical, and mechanical properties. However, these nanomaterials exhibit poor out-of-plane properties due to the weak van der Waals interaction in the transverse direction between graphitic layers. Recent theoretical studies indicate that rationally designed 3D architectures could have desirable out-of-plane properties while maintaining in-plane properties by growing CNTs and graphene into 3D architectures with a seamless nodal junction. However, the experimental realization of seamlessly-bonded architectures remains a challenge. We developed a strategy of creating 3D graphene-CNT hollow fibers with radially aligned CNTs (RACNTs) seamlessly sheathed by a cylindrical graphene layer through a one-step chemical vapor deposition using an anodized aluminum wire template. By controlling the aluminum wire diameter and anodization time, the length of the RACNTs and diameter of the graphene hollow fiber can be tuned, enabling efficient energy conversion and storage. These fibers, with a controllable surface area, meso-/micropores, and superior electrical properties, are excellent electrode materials for all-solid-state wire-shaped supercapacitors with poly(vinyl alcohol)/H2SO4 as the electrolyte and binder, exhibiting a surface-specific capacitance of 89.4 mF/cm2 and length-specific capacitance up to 23.9 mF/cm, — one to four times the corresponding record-high capacities reported for other fiber-like supercapacitors. Dye-sensitized solar cells, fabricated using the fiber as a counter electrode, showed a power conversion efficiency of 6.8% and outperformed their counterparts with an expensive Pt wire counter electrode by a factor of 2.5. These novel fiber-shaped graphene-RACNT energy conversion and storage devices are so flexible they can be woven into fabrics as power sources. PMID:26601246

  11. Three-dimensional B,N-doped Graphene Foam as a Metal-free Catalyst for Oxygen Reduction Reaction

    DTIC Science & Technology

    2013-01-01

    hexagonal boron nitride (h-BN) and C–B bond, respectively, in BN-GF and B-GF. The h-BN peak at 1400 cm1 for BN-GF may also overlap with the B–O mode for B...Societies 2013 4. Conclusions In summary, we have demonstrated the first CVD synthesis of a new class of graphene foams (GFs) doped with nitrogen, boron ...class of new graphene foams (GFs) doped with nitrogen, boron or both. Nitrogen-doped graphene foams (N-GFs) with a nitrogen doping level of 3.1 atom

  12. Binder free three-dimensional sulphur/few-layer graphene foam cathode with enhanced high-rate capability for rechargeable lithium sulphur batteries

    NASA Astrophysics Data System (ADS)

    Xi, Kai; Kidambi, Piran R.; Chen, Renjie; Gao, Chenlong; Peng, Xiaoyu; Ducati, Caterina; Hofmann, Stephan; Kumar, R. Vasant

    2014-05-01

    A novel ultra-lightweight three-dimensional (3-D) cathode system for lithium sulphur (Li-S) batteries has been synthesised by loading sulphur on to an interconnected 3-D network of few-layered graphene (FLG) via a sulphur solution infiltration method. A free-standing FLG monolithic network foam was formed as a negative of a Ni metallic foam template by CVD followed by etching away of Ni. The FLG foam offers excellent electrical conductivity, an appropriate hierarchical pore structure for containing the electro-active sulphur and facilitates rapid electron/ion transport. This cathode system does not require any additional binding agents, conductive additives or a separate metallic current collector thus decreasing the weight of the cathode by typically ~20-30 wt%. A Li-S battery with the sulphur-FLG foam cathode shows good electrochemical stability and high rate discharge capacity retention for up to 400 discharge/charge cycles at a high current density of 3200 mA g-1. Even after 400 cycles the capacity decay is only ~0.064% per cycle relative to the early (e.g. the 5th cycle) discharge capacity, while yielding an average columbic efficiency of ~96.2%. Our results indicate the potential suitability of graphene foam for efficient, ultra-light and high-performance batteries.A novel ultra-lightweight three-dimensional (3-D) cathode system for lithium sulphur (Li-S) batteries has been synthesised by loading sulphur on to an interconnected 3-D network of few-layered graphene (FLG) via a sulphur solution infiltration method. A free-standing FLG monolithic network foam was formed as a negative of a Ni metallic foam template by CVD followed by etching away of Ni. The FLG foam offers excellent electrical conductivity, an appropriate hierarchical pore structure for containing the electro-active sulphur and facilitates rapid electron/ion transport. This cathode system does not require any additional binding agents, conductive additives or a separate metallic current collector

  13. Polymer/Pristine graphene based composites: from emulsions to strong, electrically conducting foams

    SciTech Connect

    Woltornist, Steven J.; Carrillo, Jan-Michael Y.; Xu, Thomas O.; Dobrynin, Andrey V.; Adamson, Douglas H.

    2015-01-21

    The unique electrical, thermal, and mechanical properties of graphene make it a perfect candidate for applications in graphene/graphite based polymer composites, yet challenges due to the lack of solubility of pristine graphene/graphite in water and common organic solvents have limited its practical utilization. In this paper, we report a scalable and environmentally friendly technique to form water-in-oil type emulsions stabilized by overlapping pristine graphene sheets, enabling the synthesis of open cell foams containing a continuous graphitic network. Our approach utilizes the insolubility of graphene/graphite in both water and organic solvents and so does not require oxidation, reduction, surfactants, high boiling solvents, chemical functionalization, or the input of large amounts of mechanical energy or heat. At the heart of our technique is the strong attraction of graphene to high-energy oil and water interfaces. This allows for the creation of stable water-in-oil emulsions with controlled droplet size and overlapping graphene sheets playing the role of surfactant by covering the droplet surface and stabilizing the interfaces with a thin graphitic skin. Finally, these emulsions are used as templates for the synthesis of open cell foams with densities below 0.35 g/cm3 that exhibit remarkable mechanical and electrical properties including compressive moduli up to ~100 MPa, compressive strengths of over 8.3 MPa (1200 psi), and bulk conductivities approaching 7 S/m.

  14. Polymer/Pristine graphene based composites: from emulsions to strong, electrically conducting foams

    DOE PAGES

    Woltornist, Steven J.; Carrillo, Jan-Michael Y.; Xu, Thomas O.; ...

    2015-01-21

    The unique electrical, thermal, and mechanical properties of graphene make it a perfect candidate for applications in graphene/graphite based polymer composites, yet challenges due to the lack of solubility of pristine graphene/graphite in water and common organic solvents have limited its practical utilization. In this paper, we report a scalable and environmentally friendly technique to form water-in-oil type emulsions stabilized by overlapping pristine graphene sheets, enabling the synthesis of open cell foams containing a continuous graphitic network. Our approach utilizes the insolubility of graphene/graphite in both water and organic solvents and so does not require oxidation, reduction, surfactants, high boilingmore » solvents, chemical functionalization, or the input of large amounts of mechanical energy or heat. At the heart of our technique is the strong attraction of graphene to high-energy oil and water interfaces. This allows for the creation of stable water-in-oil emulsions with controlled droplet size and overlapping graphene sheets playing the role of surfactant by covering the droplet surface and stabilizing the interfaces with a thin graphitic skin. Finally, these emulsions are used as templates for the synthesis of open cell foams with densities below 0.35 g/cm3 that exhibit remarkable mechanical and electrical properties including compressive moduli up to ~100 MPa, compressive strengths of over 8.3 MPa (1200 psi), and bulk conductivities approaching 7 S/m.« less

  15. Self-Propagating Combustion Triggered Synthesis of 3D Lamellar Graphene/BaFe12O19 Composite and Its Electromagnetic Wave Absorption Properties

    PubMed Central

    Zhao, Tingkai; Ji, Xianglin; Jin, Wenbo; Yang, Wenbo; Peng, Xiarong; Duan, Shichang; Dang, Alei; Li, Hao; Li, Tiehu

    2017-01-01

    The synthesis of 3D lamellar graphene/BaFe12O19 composites was performed by oxidizing graphite and sequentially self-propagating combustion triggered process. The 3D lamellar graphene structures were formed due to the synergistic effect of the tremendous heat induced gasification as well as huge volume expansion. The 3D lamellar graphene/BaFe12O19 composites bearing 30 wt % graphene present the reflection loss peak at −27.23 dB as well as the frequency bandwidth at 2.28 GHz (< −10 dB). The 3D lamellar graphene structures could consume the incident waves through multiple reflection and scattering within the layered structures, prolonging the propagation path of electromagnetic waves in the absorbers. PMID:28336889

  16. Highly-flexible 3D Li2S/graphene cathode for high-performance lithium sulfur batteries

    NASA Astrophysics Data System (ADS)

    He, Jiarui; Chen, Yuanfu; Lv, Weiqiang; Wen, Kechun; Li, Pingjian; Qi, Fei; Wang, Zegao; Zhang, Wanli; Li, Yanrong; Qin, Wu; He, Weidong

    2016-09-01

    Three-dimensional Li2S/graphene hierarchical architecture (3DLG) is synthesized with a facile infiltration method. Highly-crystalline Li2S nanoparticles are deposited homogenously into three-dimensional graphene foam (3DGF) network grown by chemical vapor deposition (CVD), resulting in 3DLG with high surface area, porosity, flexibility and conductivity. The 3DLG is employed as flexible, free-standing and binder-free cathode without metallic current collectors or conducting additives. Due to the unique structure, the 3DLG exhibits a high discharge capacity of 894.7 mAh g-1 at 0.1 C, a high capacity retention of 87.7% after 300 cycles at 0.2 C, and the high-rate capacity up to 4 C reaches 598.6 mAh g-1. The cyclic performance is record-breaking compared to the previous reports on free-standing graphene-Li2S cathodes. Flexible lithium-sulfur batteries based on the high-capacity 3DLG cathode have promising application potentials in flexible electronics, electrical vehicles, etc.

  17. The fabrication of foam-like 3D mesoporous NiO-Ni as anode for high performance Li-ion batteries

    SciTech Connect

    Huang, Peng; Zhang, Xin; Wei, Jumeng; Pan, Jiaqi; Sheng, Yingzhou; Feng, Boxue

    2015-03-15

    Graphical abstract: Foam-like 3 dimensional (3D) mesoporous NiO on 3D micro-porous Ni was fabricated. - Highlights: • We prepare NiO-Ni foam composite via hydrothermal etching and subsequent annealing. • The NiO exhibits novel foam-like 3D mesoporous architecture. • The NiO-Ni anode shows good cycle stability. - Abstract: Foam-like three dimensional mesoporous NiO on Ni foam was fabricated via facile hydrothermal etching and subsequent annealing treatment. The porous NiO consists of a large number of nanosheets with mean thickness about 50 nm, among which a large number of mesoscopic pores with size ranges from 100 nm to 1 μm distribute. The electrochemical performance of the as-prepared NiO-Ni as anode for lithium ion battery was studied by conventional charge/discharge test, which shows excellent cycle stability and rate capability. It exhibits initial discharge and charge capacities of 979 and 707 mA h g{sup −1} at a charge/discharge rate of 0.7 C, which maintain of 747 and 738 mA h g{sup −1} after 100 cycles. Even after 60 cycles at various rates from 0.06 to 14 C, the 10th discharge and charge capacities of the NiO-Ni electrode can revert to 699 and 683 mA h g{sup −1} when lowering the charge/discharge rate to 0.06 C.

  18. Efficient Electrochemical and Photoelectrochemical Water Splitting by a 3D Nanostructured Carbon Supported on Flexible Exfoliated Graphene Foil.

    PubMed

    Hou, Yang; Qiu, Ming; Zhang, Tao; Ma, Ji; Liu, Shaohua; Zhuang, Xiaodong; Yuan, Chris; Feng, Xinliang

    2017-01-01

    A novel 3D Co-Nx |P-complex-doped carbon grown on flexible exfoliated graphene foil is designed and constructed for both electrochemical and photoelectrochemical water splitting. The coordination of Co-Nx active centers hybridized with that of neighboring P atoms enhances the electron transfer and optimizes the charge distribution of the carbon surface, which synergistically promotes reaction kinetics by providing more exposed active sites.

  19. Nanosized LiFePO4-decorated emulsion-templated carbon foam for 3D micro batteries: a study of structure and electrochemical performance.

    PubMed

    Asfaw, Habtom D; Roberts, Matthew R; Tai, Cheuk-Wai; Younesi, Reza; Valvo, Mario; Nyholm, Leif; Edström, Kristina

    2014-08-07

    In this article, we report a novel 3D composite cathode fabricated from LiFePO4 nanoparticles deposited conformally on emulsion-templated carbon foam by a sol-gel method. The carbon foam is synthesized via a facile and scalable method which involves the carbonization of a high internal phase emulsion (polyHIPE) polymer template. Various techniques (XRD, SEM, TEM and electrochemical methods) are used to fully characterize the porous electrode and confirm the distribution and morphology of the cathode active material. The major benefits of the carbon foam used in our work are closely connected with its high surface area and the plenty of space suitable for sequential coating with battery components. After coating with a cathode material (LiFePO4 nanoparticles), the 3D electrode presents a hierarchically structured electrode in which a porous layer of the cathode material is deposited on the rigid and bicontinuous carbon foam. The composite electrodes exhibit impressive cyclability and rate performance at different current densities affirming their importance as viable power sources in miniature devices. Footprint area capacities of 1.72 mA h cm(-2) at 0.1 mA cm(-2) (lowest rate) and 1.1 mA h cm(-2) at 6 mA cm(-2) (highest rate) are obtained when the cells are cycled in the range 2.8 to 4.0 V vs. lithium.

  20. Polymer/Pristine Graphene Based Composites: From Emulsions to Strong, Electrically Conducting Foams

    NASA Astrophysics Data System (ADS)

    Woltornist, Steven; Carrillo, Jan-Michael; Xu, Thomas; Dobrynin, Andrey; Adamson, Douglas

    2015-03-01

    The unique electrical, thermal and mechanical properties of graphene make it a perfect candidate for applications in graphene/graphite based polymer composites, yet challenges due to the lack of solubility of pristine graphene/graphite in water, common organic solvents, and polymer solutions and melts have limited its practical utilization. Here we report a scalable and environmentally friendly technique to form water-in-oil type emulsions stabilized by a graphitic skin consisting of overlapping pristine graphene sheets that enables the synthesis of open cell foams containing a continuous graphitic skin network. At the heart of our technique is the strong attraction of graphene to high-energy oil and water interfaces. This allows for the creation of stable water-in-oil emulsions with controlled droplet size and overlapping graphene sheets playing the role of surfactant by covering the droplet surface and stabilizing the interfaces with a thin graphitic skin. These emulsions are used as templates for the synthesis of the open cell foams with densities below 0.35 g/cm3 and exhibiting remarkable mechanical and electrical properties including compressive moduli up to ~ 100 MPa, compressive strengths of over 8.3 MPa, and bulk conductivities approaching 7 S/m.

  1. 3D polyaniline porous layer anchored pillared graphene sheets: enhanced interface joined with high conductivity for better charge storage applications.

    PubMed

    Sekar, Pandiaraj; Anothumakkool, Bihag; Kurungot, Sreekumar

    2015-04-15

    Here, we report synthesis of a 3-dimensional (3D) porous polyaniline (PANI) anchored on pillared graphene (G-PANI-PA) as an efficient charge storage material for supercapacitor applications. Benzoic acid (BA) anchored graphene, having spatially separated graphene layers (G-Bz-COOH), was used as a structure controlling support whereas 3D PANI growth has been achieved by a simple chemical oxidation of aniline in the presence of phytic acid (PA). The BA groups on G-Bz-COOH play a critical role in preventing the restacking of graphene to achieve a high surface area of 472 m(2)/g compared to reduced graphene oxide (RGO, 290 m(2)/g). The carboxylic acid (-COOH) group controls the rate of polymerization to achieve a compact polymer structure with micropores whereas the chelating nature of PA plays a crucial role to achieve the 3D growth pattern of PANI. This type of controlled interplay helps G-PANI-PA to achieve a high conductivity of 3.74 S/cm all the while maintaining a high surface area of 330 m(2)/g compared to PANI-PA (0.4 S/cm and 60 m(2)/g). G-PANI-PA thus conceives the characteristics required for facile charge mobility during fast charge-discharge cycles, which results in a high specific capacitance of 652 F/g for the composite. Owing to the high surface area along with high conductivity, G-PANI-PA displays a stable specific capacitance of 547 F/g even with a high mass loading of 3 mg/cm(2), an enhanced areal capacitance of 1.52 F/cm(2), and a volumetric capacitance of 122 F/cm(3). The reduced charge-transfer resistance (RCT) of 0.67 Ω displayed by G-PANI-PA compared to pure PANI (0.79 Ω) stands out as valid evidence of the improved charge mobility achieved by the system by growing the 3D PANI layer along the spatially separated layers of the graphene sheets. The low RCT helps the system to display capacitance retention as high as 65% even under a high current dragging condition of 10 A/g. High charge/discharge rates and good cycling stability are the other

  2. Superior Mechanical Properties of Epoxy Composites Reinforced by 3D Interconnected Graphene Skeleton.

    PubMed

    Ni, Ya; Chen, Lei; Teng, Kunyue; Shi, Jie; Qian, Xiaoming; Xu, Zhiwei; Tian, Xu; Hu, Chuansheng; Ma, Meijun

    2015-06-03

    Epoxy-based composites reinforced by three-dimensional graphene skeleton (3DGS) were fabricated in resin transfer molding method with respect to the difficulty in good dispersion and arrangement of graphene sheets in composites by directly mixing graphene and epoxy. 3DGS was synthesized in the process of self-assembly and reduction with poly(amidoamine) dendrimers. In the formation of 3DGS, graphene sheets were in good dispersion and ordered state, which resulted in exceptional mechanical properties and thermal stability for epoxy composites. For 3DGS/epoxy composites, the tensile and compressive strengths significantly increased by 120.9% and 148.3%, respectively, as well as the glass transition temperature, which increased by a notable 19 °C, unlike the thermal exfoliation graphene/epoxy composites via direct-mixing route, which increased by only 0.20 wt % content of fillers. Relative to the graphene/epoxy composites in direct-mixing method mentioned in literature, the increase in tensile and compressive strengths of 3DGS/epoxy composites was at least twofold and sevenfold, respectively. It can be expected that 3DGS, which comes from preforming graphene sheets orderly and dispersedly, would replace graphene nanosheets in polymer nanocomposite reinforcement and endow composites with unique structure and some unexpected performance.

  3. Noninvasive 3D Visualization of Defects and Crack Propagation in Layered Foam Structures by Phase Contrast Microimaging

    NASA Technical Reports Server (NTRS)

    Hu, Z. W.; DeCarlo, F.

    2006-01-01

    Applications of polymeric foams in our modern society continue to grow because of their light weight, high strength, excellent thermal and mechanical insulation, and the ease of engineering. Among others, closed-cell foam has been structurally used for thermally insulating the shuttle external tank. However, internal defects of the foams were difficult to observe non-invasively due to limited sensitivity to the low-density structures possessed by traditional imaging tools such as computed X-ray tomography By combining phase contrast X-ray imaging with pressure loading, we succeeded in precisely mapping intact cellular structure and defects inside the bulk of layered foam and visualizing its subsequent response to the pressure in three-dimensional space. The work demonstrated a powerfir1 approach for yielding insight into underlying problems in lightweight cellular materials otherwise unobtainable.

  4. One-Pot Synthesis of Fe3O4 Nanoparticle Loaded 3D Porous Graphene Nanocomposites with Enhanced Nanozyme Activity for Glucose Detection.

    PubMed

    Wang, Qingqing; Zhang, Xueping; Huang, Liang; Zhang, Zhiquan; Dong, Shaojun

    2017-03-01

    A novel one-pot strategy is proposed to fabricate 3D porous graphene (3D GN) decorated with Fe3O4 nanoparticles (Fe3O4 NPs) by using hemin as iron source. During the process, graphene oxide was simultaneously reduced and self-assembled to form 3D graphene hydrogel while Fe3O4 NPs synthesized from hemin distributed uniformly on 3D GN. The preparation process is simple, facile, economical, and green. The obtained freeze-dried product (3D GH-5) exhibits outstanding peroxidase-like activity. Compared to the traditional 2D graphene-based nanocomposites, the introduced 3D porous structure dramatically improved the catalytic activity, as well as the catalysis velocity and its affinity for substrate. The high catalytic activity could be ascribed to the formation of Fe3O4 NPs and 3D porous graphene structures. Based on its peroxidase-like activity, 3D GH-5 was used for colorimetric determination of glucose with a low detection limit of 0.8 μM.

  5. 3D architecture of a graphene/CoMoO4 composite for asymmetric supercapacitors usable at various temperatures.

    PubMed

    Jiang, Yaru; Zheng, Xin; Yan, Xiaoqin; Li, Yong; Zhao, Xuan; Zhang, Yue

    2017-05-01

    Designing and optimizing the electrode materials and studying the electrochemical performance or cycle life of the supercapacitor under different working conditions are crucial to its practical application. Herein, we proposed a rational design of 3D-graphene/CoMoO4 nanoplates by a facile two-step hydrothermal method. Owing to the high electron transfer rate of graphene and the high activity of the CoMoO4 nanoplates, the three-dimensional electrode architectures achieved remarkable electrochemical performances with high areal specific capacitance (1255.24F/g at 1A/g) and superior cycling stability (91.3% of the original specific capacitance after 3000 cycles at 1A/g). The all-solid-state asymmetric supercapacitor composed of 3D-graphene/CoMoO4 and activated carbon (AC) exhibited a specific capacitance of 109F/g at 0.2A/g and an excellent cycling stability with only 12.1% of the initial specific capacitance off after 3000 cycles at 2A/g. The effects of temperature and charge-discharge current densities on the charge storage capacity of the supercapacitor were also investigated in detail for practical applications.

  6. High-density 3D graphene-based monolith and related materials, methods, and devices

    DOEpatents

    Worsley, Marcus A.; Baumann, Theodore F.; Biener, Juergen; Charnvanichborikarn, Supakit; Kucheyev, Sergei; Montalvo, Elizabeth; Shin, Swanee; Tylski, Elijah

    2017-03-21

    A composition comprising at least one high-density graphene-based monolith, said monolith comprising a three-dimensional structure of graphene sheets crosslinked by covalent carbon bonds and having a density of at least 0.1 g/cm.sup.3. Also provided is a method comprising: preparing a reaction mixture comprising a suspension and at least one catalyst, said suspension selected from a graphene oxide (GO) suspension and a carbon nanotube suspension; curing the reaction mixture to produce a wet gel; drying the wet gel to produce a dry gel, said drying step is substantially free of supercritical drying and freeze drying; and pyrolyzing the dry gel to produce a high-density graphene-based monolith. Exceptional combinations of properties are achieved including high conductive and mechanical properties.

  7. Thermal transport in three-dimensional foam architectures of few-layer graphene and ultrathin graphite.

    PubMed

    Pettes, Michael Thompson; Ji, Hengxing; Ruoff, Rodney S; Shi, Li

    2012-06-13

    At a very low solid concentration of 0.45 ± 0.09 vol %, the room-temperature thermal conductivity (κ(GF)) of freestanding graphene-based foams (GF), comprised of few-layer graphene (FLG) and ultrathin graphite (UG) synthesized through the use of methane chemical vapor deposition on reticulated nickel foams, was increased from 0.26 to 1.7 W m(-1) K(-1) after the etchant for the sacrificial nickel support was changed from an aggressive hydrochloric acid solution to a slow ammonium persulfate etchant. In addition, κ(GF) showed a quadratic dependence on temperature between 11 and 75 K and peaked at about 150 K, where the solid thermal conductivity (κ(G)) of the FLG and UG constituents reached about 1600 W m(-1) K(-1), revealing the benefit of eliminating internal contact thermal resistance in the continuous GF structure.

  8. Heteroatom Polymer-Derived 3D High-Surface-Area and Mesoporous Graphene Sheet-Like Carbon for Supercapacitors.

    PubMed

    Sheng, Haiyang; Wei, Min; D'Aloia, Alyssa; Wu, Gang

    2016-11-09

    Current supercapacitors suffer from low energy density mainly due to the high degree of microporosity and insufficient hydrophilicity of their carbon electrodes. Development of a supercapacitor capable of simultaneously storing as much energy as a battery, along with providing sufficient power and long cycle stability would be valued for energy storage applications and innovations. Differing from commonly studied reduced graphene oxides, in this work we identified an inexpensive heteroatom polymer (polyaniline-PANI) as a carbon/nitrogen precursor, and applied a controlled thermal treatment at elevated temperature to convert PANI into 3D high-surface-area graphene-sheet-like carbon materials. During the carbonization process, various transition metals including Fe, Co, and Ni were added, which play critical roles in both catalyzing the graphitization and serving as pore forming agents. Factors including post-treatments, heating temperatures, and types of metal were found crucial for achieving enhanced capacitance performance on resulting carbon materials. Using FeCl3 as precursor along with optimal heating temperature 1000 °C and mixed acid treatment (HCl+HNO3), the highest Brunauer-Emmett-Teller (BET) surface area of 1645 m(2)g(-1) was achieved on the mesopore dominant graphene-sheet-like carbon materials. The unique morphologies featured with high-surface areas, dominant mesopores, proper nitrogen doping, and 3D graphene-like structures correspond to remarkably enhanced electrochemical specific capacitance up to 478 Fg(-1) in 1.0 M KOH at a scan rate of 5 mV s(-1). Furthermore, in a real two-electrode system of a symmetric supercapacitor, a specific capacitance of 235 Fg(-1) using Nafion binder is obtained under a current density of 1 Ag(-1) by galvanostatic charge-discharge tests in 6.0 M KOH. Long-term cycle stability up to 5000 cycles by using PVDF binder in electrode was systematically evaluated as a function of types of metals and current densities.

  9. Nanosized LiFePO4-decorated emulsion-templated carbon foam for 3D micro batteries: a study of structure and electrochemical performance

    NASA Astrophysics Data System (ADS)

    Asfaw, Habtom D.; Roberts, Matthew R.; Tai, Cheuk-Wai; Younesi, Reza; Valvo, Mario; Nyholm, Leif; Edström, Kristina

    2014-07-01

    In this article, we report a novel 3D composite cathode fabricated from LiFePO4 nanoparticles deposited conformally on emulsion-templated carbon foam by a sol-gel method. The carbon foam is synthesized via a facile and scalable method which involves the carbonization of a high internal phase emulsion (polyHIPE) polymer template. Various techniques (XRD, SEM, TEM and electrochemical methods) are used to fully characterize the porous electrode and confirm the distribution and morphology of the cathode active material. The major benefits of the carbon foam used in our work are closely connected with its high surface area and the plenty of space suitable for sequential coating with battery components. After coating with a cathode material (LiFePO4 nanoparticles), the 3D electrode presents a hierarchically structured electrode in which a porous layer of the cathode material is deposited on the rigid and bicontinuous carbon foam. The composite electrodes exhibit impressive cyclability and rate performance at different current densities affirming their importance as viable power sources in miniature devices. Footprint area capacities of 1.72 mA h cm-2 at 0.1 mA cm-2 (lowest rate) and 1.1 mA h cm-2 at 6 mA cm-2 (highest rate) are obtained when the cells are cycled in the range 2.8 to 4.0 V vs. lithium.In this article, we report a novel 3D composite cathode fabricated from LiFePO4 nanoparticles deposited conformally on emulsion-templated carbon foam by a sol-gel method. The carbon foam is synthesized via a facile and scalable method which involves the carbonization of a high internal phase emulsion (polyHIPE) polymer template. Various techniques (XRD, SEM, TEM and electrochemical methods) are used to fully characterize the porous electrode and confirm the distribution and morphology of the cathode active material. The major benefits of the carbon foam used in our work are closely connected with its high surface area and the plenty of space suitable for sequential coating

  10. A Flexible and Highly Sensitive Pressure Sensor Based on a PDMS Foam Coated with Graphene Nanoplatelets

    PubMed Central

    Rinaldi, Andrea; Tamburrano, Alessio; Fortunato, Marco; Sarto, Maria Sabrina

    2016-01-01

    The demand for high performance multifunctional wearable devices is more and more pushing towards the development of novel low-cost, soft and flexible sensors with high sensitivity. In the present work, we describe the fabrication process and the properties of new polydimethylsiloxane (PDMS) foams loaded with multilayer graphene nanoplatelets (MLGs) for application as high sensitive piezoresistive pressure sensors. The effective DC conductivity of the produced foams is measured as a function of MLG loading. The piezoresistive response of the MLG-PDMS foam-based sensor at different strain rates is assessed through quasi-static pressure tests. The results of the experimental investigations demonstrated that sensor loaded with 0.96 wt.% of MLGs is characterized by a highly repeatable pressure-dependent conductance after a few stabilization cycles and it is suitable for detecting compressive stresses as low as 10 kPa, with a sensitivity of 0.23 kPa−1, corresponding to an applied pressure of 70 kPa. Moreover, it is estimated that the sensor is able to detect pressure variations of ~1 Pa. Therefore, the new graphene-PDMS composite foam is a lightweight cost-effective material, suitable for sensing applications in the subtle or low and medium pressure ranges. PMID:27999251

  11. A Flexible and Highly Sensitive Pressure Sensor Based on a PDMS Foam Coated with Graphene Nanoplatelets.

    PubMed

    Rinaldi, Andrea; Tamburrano, Alessio; Fortunato, Marco; Sarto, Maria Sabrina

    2016-12-16

    The demand for high performance multifunctional wearable devices is more and more pushing towards the development of novel low-cost, soft and flexible sensors with high sensitivity. In the present work, we describe the fabrication process and the properties of new polydimethylsiloxane (PDMS) foams loaded with multilayer graphene nanoplatelets (MLGs) for application as high sensitive piezoresistive pressure sensors. The effective DC conductivity of the produced foams is measured as a function of MLG loading. The piezoresistive response of the MLG-PDMS foam-based sensor at different strain rates is assessed through quasi-static pressure tests. The results of the experimental investigations demonstrated that sensor loaded with 0.96 wt.% of MLGs is characterized by a highly repeatable pressure-dependent conductance after a few stabilization cycles and it is suitable for detecting compressive stresses as low as 10 kPa, with a sensitivity of 0.23 kPa(-1), corresponding to an applied pressure of 70 kPa. Moreover, it is estimated that the sensor is able to detect pressure variations of ~1 Pa. Therefore, the new graphene-PDMS composite foam is a lightweight cost-effective material, suitable for sensing applications in the subtle or low and medium pressure ranges.

  12. High Sensitivity Gas Detection Using a Macroscopic Three-Dimensional Graphene Foam Network

    PubMed Central

    Yavari, Fazel; Chen, Zongping; Thomas, Abhay V.; Ren, Wencai; Cheng, Hui-Ming; Koratkar, Nikhil

    2011-01-01

    Nanostructures are known to be exquisitely sensitive to the chemical environment and offer ultra-high sensitivity for gas-sensing. However, the fabrication and operation of devices that use individual nanostructures for sensing is complex, expensive and suffers from poor reliability due to contamination and large variability from sample-to-sample. By contrast, conventional solid-state and conducting-polymer sensors offer excellent reliability but suffer from reduced sensitivity at room-temperature. Here we report a macro graphene foam-like three-dimensional network which combines the best of both worlds. The walls of the foam are comprised of few-layer graphene sheets resulting in high sensitivity; we demonstrate parts-per-million level detection of NH3 and NO2 in air at room-temperature. Further, the foam is a mechanically robust and flexible macro-scale network that is easy to contact (without Lithography) and can rival the durability and affordability of traditional sensors. Moreover, Joule-heating expels chemisorbed molecules from the foam's surface leading to fully-reversible and low-power operation. PMID:22355681

  13. Three-dimensional nickel foam/graphene/NiCo2O4 as high-performance electrodes for supercapacitors

    NASA Astrophysics Data System (ADS)

    Nguyen, Van Hoa; Shim, Jae-Jin

    2015-01-01

    A facile and efficient two-step method for the decoration of graphene sheets and nickel cobalt oxide (NiCo2O4) nanoparticles on conducting nickel foam was developed. First, graphene and a bimetallic (Ni, Co) hydroxide precursor were deposited on a Ni foam support by electrodeposition followed by a thermal transformation of the bimetallic hydroxide to NiCo2O4. The graphene layer with a thickness of a few nanometers was decorated with NiCo2O4 nanoparticles, ranging in size from 3 to 5 nm. The nickel foam electrode supported graphene and NiCo2O4 exhibited rapid electron and ion transport, large electroactive surface area, and excellent structural stability. The specific capacitance of the obtained electrode was as high as 1950 F g-1 at a high current density of 7.5 A g-1, suggesting its promising applications as an efficient electrode for electrochemical capacitors.

  14. Pt nanoparticle and Fe,N-codoped 3D graphene as synergistic electrocatalyst for oxygen reduction reaction

    NASA Astrophysics Data System (ADS)

    Qin, Yong; Chao, Lei; He, Jing Jing; Liu, Yang; Chu, Fuqiang; Cao, Jianyu; Kong, Yong; Tao, Yongxin

    2016-12-01

    Ultrafine Pt nanoparticles (PtNPs) with the diameter of ∼2.5 nm were successfully confined within Fe,N-codoped robust 3D graphene (Fe-N/R3DG) via facile polyol-assisted reduction strategy. Owing to the synergistic effect between the active catalyst (PtNPs) and the support (Fe-N/R3DG), the as-obtained composite exhibited better cyclic stability and long-term durability as well as less methanol toxicity, moreover, 8 times higher specific activity than the commercial Pt/C for oxygen reduction reaction (ORR) in alkaline medium. The results bring new insight into the design of excellent ORR catalyst.

  15. Strain-rate sensitivity of foam materials: A numerical study using 3D image-based finite element model

    NASA Astrophysics Data System (ADS)

    Sun, Yongle; Li, Q. M.; Withers, P. J.

    2015-09-01

    Realistic simulations are increasingly demanded to clarify the dynamic behaviour of foam materials, because, on one hand, the significant variability (e.g. 20% scatter band) of foam properties and the lack of reliable dynamic test methods for foams bring particular difficulty to accurately evaluate the strain-rate sensitivity in experiments; while on the other hand numerical models based on idealised cell structures (e.g. Kelvin and Voronoi) may not be sufficiently representative to capture the actual structural effect. To overcome these limitations, the strain-rate sensitivity of the compressive and tensile properties of closed-cell aluminium Alporas foam is investigated in this study by means of meso-scale realistic finite element (FE) simulations. The FE modelling method based on X-ray computed tomography (CT) image is introduced first, as well as its applications to foam materials. Then the compression and tension of Alporas foam at a wide variety of applied nominal strain-rates are simulated using FE model constructed from the actual cell geometry obtained from the CT image. The stain-rate sensitivity of compressive strength (collapse stress) and tensile strength (0.2% offset yield point) are evaluated when considering different cell-wall material properties. The numerical results show that the rate dependence of cell-wall material is the main cause of the strain-rate hardening of the compressive and tensile strengths at low and intermediate strain-rates. When the strain-rate is sufficiently high, shock compression is initiated, which significantly enhances the stress at the loading end and has complicated effect on the stress at the supporting end. The plastic tensile wave effect is evident at high strain-rates, but shock tension cannot develop in Alporas foam due to the softening associated with single fracture process zone occurring in tensile response. In all cases the micro inertia of individual cell walls subjected to localised deformation is found to

  16. Microwave-assisted synthesis of simonkolleite nanoplatelets on nickel foam-graphene with enhanced surface area for high-performance supercapacitors.

    PubMed

    Khamlich, S; Mokrani, T; Dhlamini, M S; Mothudi, B M; Maaza, M

    2016-01-01

    Simonkolleite (Zn5(OH)8Cl2·H2O) nanoplatelets has been deposited on nickel foam-supported graphene by using an efficient microwave-assisted hydrothermal method. The three-dimensional (3D) porous microstructure of the as-fabricated nickel foam-graphene/simonkolleite (NiF-G/SimonK) composite is beneficial to electrolyte penetration and ions exchange, whereas graphene provide improved electronic conductivity. Structural and morphological characterizations confirmed the presence of highly crystalline hexagonal-shaped nanoplatelets of simonkolleite. Field emission scanning electron microscope (FE-SEM) of the NiF-G/SimonK composite revealed that the SimonK nanoplatelets were evenly distributed on the surface of NiF-G and interlaced with each other, resulting in a higher specific surface area of 35.69 m(2) g(-1) compared to SimonK deposited directly on NiF 17.2 m(2) g(-1). Electrochemical measurements demonstrated that the NiF-G/SimonK composite exhibit a high specific capacitance of 836 F g(-1) at a current density of 1 A g(-1), and excellent rate capability and cycling stability with capacitance retention of 92% after 5000 charge/discharge cycles.

  17. 3D Flower-like β-MnO2/Reduced Graphene Oxide Nanocomposites for Catalytic Ozonation of Dichloroacetic Acid

    PubMed Central

    Li, Gang; Li, Kezheng; Liu, Aijuan; Yang, Ping; Du, Yukou; Zhu, Mingshan

    2017-01-01

    Considering the potential use of manganese oxide based nanocomposite in catalytic ozonation of water contaminant, we report unique three-dimensional (3D) nanoarchitectures composed of β-MnO2 and reduced graphene oxide (RGO) for catalytic ozonation of dichloroacetic acid (DCAA) from drinking water. The catalytic results show that the 3D β-MnO2/RGO nanocomposites (FMOG) can be used as efficient and stable ozonation catalysts to eliminate DCAA from water. The probable mechanism of catalytic ozonation was also proposed by detecting intermediates using gas chromatography-mass spectrometry. This result likely paves a facile avenue and initiates new opportunities for the exploration of heterogeneous catalysts for the removal of disinfection by-products from drinking water.

  18. 3D Flower-like β-MnO2/Reduced Graphene Oxide Nanocomposites for Catalytic Ozonation of Dichloroacetic Acid

    NASA Astrophysics Data System (ADS)

    Li, Gang; Li, Kezheng; Liu, Aijuan; Yang, Ping; Du, Yukou; Zhu, Mingshan

    2017-03-01

    Considering the potential use of manganese oxide based nanocomposite in catalytic ozonation of water contaminant, we report unique three-dimensional (3D) nanoarchitectures composed of β-MnO2 and reduced graphene oxide (RGO) for catalytic ozonation of dichloroacetic acid (DCAA) from drinking water. The catalytic results show that the 3D β-MnO2/RGO nanocomposites (FMOG) can be used as efficient and stable ozonation catalysts to eliminate DCAA from water. The probable mechanism of catalytic ozonation was also proposed by detecting intermediates using gas chromatography-mass spectrometry. This result likely paves a facile avenue and initiates new opportunities for the exploration of heterogeneous catalysts for the removal of disinfection by-products from drinking water.

  19. A Novel Role of Three Dimensional Graphene Foam to Prevent Heater Failure during Boiling

    PubMed Central

    Ahn, Ho Seon; Kim, Ji Min; Park, Chibeom; Jang, Ji-Wook; Lee, Jae Sung; Kim, Hyungdae; Kaviany, Massoud; Kim, Moo Hwan

    2013-01-01

    We report a novel boiling heat transfer (NBHT) in reduced graphene oxide (RGO) suspended in water (RGO colloid) near critical heat flux (CHF), which is traditionally the dangerous limitation of nucleate boiling heat transfer because of heater failure. When the heat flux reaches the maximum value (CHF) in RGO colloid pool boiling, the wall temperature increases gradually and slowly with an almost constant heat flux, contrary to the rapid wall temperature increase found during water pool boiling. The gained time by NBHT would provide the safer margin of the heat transfer and the amazing impact on the thermal system as the first report of graphene application. In addition, the CHF and boiling heat transfer performance also increase. This novel boiling phenomenon can effectively prevent heater failure because of the role played by the self-assembled three-dimensional foam-like graphene network (SFG). PMID:23743619

  20. Self-assembled foam-like graphene networks formed through nucleate boiling

    PubMed Central

    Ahn, Ho Seon; Jang, Ji-Wook; Seol, Minsu; Kim, Ji Min; Yun, Dong-Jin; Park, Chibeom; Kim, Hyungdae; Youn, Duck Hyun; Kim, Jae Young; Park, Gunyeop; Park, Su Cheong; Kim, Jin Man; Yu, Dong In; Yong, Kijung; Kim, Moo Hwan; Lee, Jae Sung

    2013-01-01

    Self-assembled foam-like graphene (SFG) structures were formed using a simple nucleate boiling method, which is governed by the dynamics of bubble generation and departure in the graphene colloid solution. The conductivity and sheet resistance of the calcined (400°C) SFG film were 11.8 S·cm–1 and 91.2 Ω□−1, respectively, and were comparable to those of graphene obtained by chemical vapor deposition (CVD) (~10 S·cm–1). The SFG structures can be directly formed on any substrate, including transparent conductive oxide (TCO) glasses, metals, bare glasses, and flexible polymers. As a potential application, SFG formed on fluorine-doped tin oxide (FTO) exhibited a slightly better overall efficiency (3.6%) than a conventional gold electrode (3.4%) as a cathode of quantum dot sensitized solar cells (QDSSCs). PMID:23466511

  1. A novel role of three dimensional graphene foam to prevent heater failure during boiling.

    PubMed

    Ahn, Ho Seon; Kim, Ji Min; Park, Chibeom; Jang, Ji-Wook; Lee, Jae Sung; Kim, Hyungdae; Kaviany, Massoud; Kim, Moo Hwan

    2013-01-01

    We report a novel boiling heat transfer (NBHT) in reduced graphene oxide (RGO) suspended in water (RGO colloid) near critical heat flux (CHF), which is traditionally the dangerous limitation of nucleate boiling heat transfer because of heater failure. When the heat flux reaches the maximum value (CHF) in RGO colloid pool boiling, the wall temperature increases gradually and slowly with an almost constant heat flux, contrary to the rapid wall temperature increase found during water pool boiling. The gained time by NBHT would provide the safer margin of the heat transfer and the amazing impact on the thermal system as the first report of graphene application. In addition, the CHF and boiling heat transfer performance also increase. This novel boiling phenomenon can effectively prevent heater failure because of the role played by the self-assembled three-dimensional foam-like graphene network (SFG).

  2. Self-Assembly of Single-Layer CoAl-Layered Double Hydroxide Nanosheets on 3D Graphene Network Used as Highly Efficient Electrocatalyst for Oxygen Evolution Reaction.

    PubMed

    Ping, Jianfeng; Wang, Yixian; Lu, Qipeng; Chen, Bo; Chen, Junze; Huang, Ying; Ma, Qinglang; Tan, Chaoliang; Yang, Jian; Cao, Xiehong; Wang, Zhijuan; Wu, Jian; Ying, Yibin; Zhang, Hua

    2016-09-01

    A non-noble metal based 3D porous electrocatalyst is prepared by self-assembly of the liquid-exfoliated single-layer CoAl-layered double hydroxide nanosheets (CoAl-NSs) onto 3D graphene network, which exhibits higher catalytic activity and better stability for electrochemical oxygen evolution reaction compared to the commercial IrO2 nanoparticle-based 3D porous electrocatalyst.

  3. Poly (vinylidene fluoride)/graphene nano-platelets electrically conductive composite foam for thermoelectric applications

    NASA Astrophysics Data System (ADS)

    Sun, Yu-Chen; Terakita, Daryl; Tseng, Alex C.; Naguib, Hani E.

    2015-04-01

    In this paper, we present the next generation of polymer based composite foam material fabricated from poly(vinylidene fluoride) (PVDF) and graphene nano-platelets (GNPs) as secondary fillers. We discovered that such composite material has thermoelectric properties and has the potential to be used in energy harvesting applications. The samples were fabricated though melt blending methods, which is a cheaper, simpler process and can be easily scaled up to industrial level for mass production. Our results indicate that melt blending processes can produce either similar or superior results compared to traditional solvent casting methods. In addition, we utilized a novel batch foaming method and successfully created closed-cell structure for the composite material. Our results also show that the thermal conductivity of PVDF/GNP foam samples have approximately an order of magnitude drop compared to solid samples, which is desired for thermoelectric materials. Furthermore, we observed a change in the electrical conductivity threshold of the GNP fillers after foaming. We report a Seebeck coefficient of 217 μV/K for 15 wt% GNP/PVDF foam samples, which is approximately 10 times higher than values reported previously.

  4. 3D Graphene Functionalized by Covalent Organic Framework Thin Film as Capacitive Electrode in Alkaline Media.

    PubMed

    Zha, Zeqi; Xu, Lirong; Wang, Zhikui; Li, Xiaoguang; Pan, Qinmin; Hu, Pingan; Lei, Shengbin

    2015-08-19

    To harness the electroactivity of anthraquinone as an electrode material, a great recent effort have been invested to composite anthraquinone with carbon materials to improve the conductivity. Here we report on a noncovalent way to modify three-dimensional graphene with anthraquinone moieties through on-surface synthesis of two-dimensional covalent organic frameworks. We incorporate 2,6-diamino-anthraquinone moieties into COF through Schiff-base reaction with benzene-1,3,5-tricarbaldehyde. The synthesized COF -graphene composite exhibits large specific capacitance of 31.7 mF/cm(2). Long-term galvanostatic charge/discharge cycling experiments revealed a decrease of capacitance, which was attributed to the loss of COF materials and electrostatic repulsion accumulated during charge-discharge circles which result in the poor electrical conductivity between 2D COF layers.

  5. Unimpeded permeation of water through biocidal graphene oxide sheets anchored on to 3D porous polyolefinic membranes

    NASA Astrophysics Data System (ADS)

    Mural, Prasanna Kumar S.; Jain, Shubham; Kumar, Sachin; Madras, Giridhar; Bose, Suryasarathi

    2016-04-01

    3D porous membranes were developed by etching one of the phases (here PEO, polyethylene oxide) from melt-mixed PE/PEO binary blends. Herein, we have systematically discussed the development of these membranes using X-ray micro-computed tomography. The 3D tomograms of the extruded strands and hot-pressed samples revealed a clear picture as to how the morphology develops and coarsens over a function of time during post-processing operations like compression molding. The coarsening of PE/PEO blends was traced using X-ray micro-computed tomography and scanning electron microscopy (SEM) of annealed blends at different times. It is now understood from X-ray micro-computed tomography that by the addition of a compatibilizer (here lightly maleated PE), a stable morphology can be visualized in 3D. In order to anchor biocidal graphene oxide sheets onto these 3D porous membranes, the PE membranes were chemically modified with acid/ethylene diamine treatment to anchor the GO sheets which were further confirmed by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and surface Raman mapping. The transport properties through the membrane clearly reveal unimpeded permeation of water which suggests that anchoring GO on to the membranes does not clog the pores. Antibacterial studies through the direct contact of bacteria with GO anchored PE membranes resulted in 99% of bacterial inactivation. The possible bacterial inactivation through physical disruption of the bacterial cell wall and/or reactive oxygen species (ROS) is discussed herein. Thus this study opens new avenues in designing polyolefin based antibacterial 3D porous membranes for water purification.3D porous membranes were developed by etching one of the phases (here PEO, polyethylene oxide) from melt-mixed PE/PEO binary blends. Herein, we have systematically discussed the development of these membranes using X-ray micro-computed tomography. The 3D tomograms of the extruded strands and

  6. Strontium eluting graphene hybrid nanoparticles augment osteogenesis in a 3D tissue scaffold.

    PubMed

    Kumar, Sachin; Chatterjee, Kaushik

    2015-02-07

    The objective of this work was to prepare hybrid nanoparticles of graphene sheets decorated with strontium metallic nanoparticles and demonstrate their advantages in bone tissue engineering. Strontium-decorated reduced graphene oxide (RGO_Sr) hybrid nanoparticles were synthesized by the facile reduction of graphene oxide and strontium nitrate. X-ray diffraction, transmission electron microscopy, and atomic force microscopy revealed that the hybrid particles were composed of RGO sheets decorated with 200-300 nm metallic strontium particles. Thermal gravimetric analysis further confirmed the composition of the hybrid particles as 22 wt% of strontium. Macroporous tissue scaffolds were prepared by incorporating RGO_Sr particles in poly(ε-caprolactone) (PCL). The PCL/RGO_Sr scaffolds were found to elute strontium ions in aqueous medium. Osteoblast proliferation and differentiation was significantly higher in the PCL scaffolds containing the RGO_Sr particles in contrast to neat PCL and PCL/RGO scaffolds. The increased biological activity can be attributed to the release of strontium ions from the hybrid nanoparticles. This study demonstrates that composites prepared using hybrid nanoparticles that elute strontium ions can be used to prepare multifunctional scaffolds with good mechanical and osteoinductive properties. These findings have important implications for designing the next generation of biomaterials for use in tissue regeneration.

  7. An environmentally friendly method for the fabrication of reduced graphene oxide foam with a super oil absorption capacity.

    PubMed

    He, Yongqiang; Liu, Yue; Wu, Tao; Ma, Junkui; Wang, Xingrui; Gong, Qiaojuan; Kong, Weina; Xing, Fubao; Liu, Yu; Gao, Jianping

    2013-09-15

    Three kinds of graphene oxide (GO) foams were fabricated using different freezing methods (unidirectional freezing drying (UDF), non-directional freezing drying, and air freezing drying), and the corresponding reduced graphene oxide (RGO) foams were prepared by their thermal reduction of those GO foams. These RGO foams were characterized by Fourier transform infrared spectroscopy, thermal gravimetric analysis, X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy. The absorption process and the factors that influence the absorption capacity were investigated. The RGO foams are hydrophobic and showed extremely high absorbing abilities for organic liquids. The absorption capacity of the RGO foams made by UDF was higher than 100 g g(-1) for all the oils tested (gasoline, diesel oil, pump oil, lubricating oil and olive oil) and had the highest value of about 122 g g(-1) for olive oil. The oil absorption capacity of the GO foams was lower than that of the RGO foams, but for olive oil, the absorption capacity was still high than 70 g g(-1), which is higher than that of most oil absorbents.

  8. Lanthanum-catalysed synthesis of microporous 3D graphene-like carbons in a zeolite template

    NASA Astrophysics Data System (ADS)

    Kim, Kyoungsoo; Lee, Taekyoung; Kwon, Yonghyun; Seo, Yongbeom; Song, Jongchan; Park, Jung Ki; Lee, Hyunsoo; Park, Jeong Young; Ihee, Hyotcherl; Cho, Sung June; Ryoo, Ryong

    2016-07-01

    Three-dimensional graphene architectures with periodic nanopores—reminiscent of zeolite frameworks—are of topical interest because of the possibility of combining the characteristics of graphene with a three-dimensional porous structure. Lately, the synthesis of such carbons has been approached by using zeolites as templates and small hydrocarbon molecules that can enter the narrow pore apertures. However, pyrolytic carbonization of the hydrocarbons (a necessary step in generating pure carbon) requires high temperatures and results in non-selective carbon deposition outside the pores. Here, we demonstrate that lanthanum ions embedded in zeolite pores can lower the temperature required for the carbonization of ethylene or acetylene. In this way, a graphene-like carbon structure can be selectively formed inside the zeolite template, without carbon being deposited at the external surfaces. X-ray diffraction data from zeolite single crystals after carbonization indicate that electron densities corresponding to carbon atoms are generated along the walls of the zeolite pores. After the zeolite template is removed, the carbon framework exhibits an electrical conductivity that is two orders of magnitude higher than that of amorphous mesoporous carbon. Lanthanum catalysis allows a carbon framework to form in zeolite pores with diameters of less than 1 nanometre; as such, microporous carbon nanostructures can be reproduced with various topologies corresponding to different zeolite pore sizes and shapes. We demonstrate carbon synthesis for large-pore zeolites (FAU, EMT and beta), a one-dimensional medium-pore zeolite (LTL), and even small-pore zeolites (MFI and LTA). The catalytic effect is a common feature of lanthanum, yttrium and calcium, which are all carbide-forming metal elements. We also show that the synthesis can be readily scaled up, which will be important for practical applications such as the production of lithium-ion batteries and zeolite-like catalyst

  9. Fabrication of graphene foam supported carbon nanotube/polyaniline hybrids for high-performance supercapacitor applications

    NASA Astrophysics Data System (ADS)

    Yang, Hongxia; Wang, Nan; Xu, Qun; Chen, Zhimin; Ren, Yumei; Razal, Joselito M.; Chen, Jun

    2014-12-01

    A large-scale, high-powered energy storage system is crucial for addressing the energy problem. The development of high-performance materials is a key issue in realizing the grid-scale applications of energy-storage devices. In this work, we describe a simple and scalable method for fabricating hybrids (graphene-pyrrole/carbon nanotube-polyaniline (GPCP)) using graphene foam as the supporting template. Graphene-pyrrole (G-Py) aerogels are prepared via a green hydrothermal route from two-dimensional materials such as graphene sheets, while a carbon nanotube/polyaniline (CNT/PANI) composite dispersion is obtained via the in situ polymerization method. The functional nanohybrid materials of GPCP can be assembled by simply dipping the prepared G-py aerogels into the CNT/PANI dispersion. The morphology of the obtained GPCP is investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), which revealed that the CNT/PANI was uniformly deposited onto the surfaces of the graphene. The as-synthesized GPCP maintains its original three-dimensional hierarchical porous architecture, which favors the diffusion of the electrolyte ions into the inner region of the active materials. Such hybrid materials exhibit significant specific capacitance of up to 350 F g-1, making them promising in large-scale energy-storage device applications.

  10. Reduced graphene oxide hydrogels deposited in nickel foam for supercapacitor applications: Toward high volumetric capacitance

    SciTech Connect

    Pham, Viet Hung; Dickerson, James H.

    2016-02-21

    Graphene hydrogels have been considered as ideal materials for high-performance supercapacitors. However, their low volumetric capacitance significantly limits its real application. In this study, we report an environment-friendly and scalable method to prepare high packing density, electrochemically reduced graphene oxide hydrogels (ERGO) for supercapacitor application by the electrophoretic deposition of graphene oxide onto nickel foam, followed by the electrochemical reduction and hydraulic compression of the deposited materials. The as-prepared ERGO on nickel foam was hydraulic compressed up to 20 tons, resulting in an increase of the packing density of ERGO from 0.0098 to 1.32 g cm–3. Consequently, the volumetric capacitance and volumetric energy density of ERGOs greatly increased from 1.58 F cm–3 and 0.053 Wh cm–3 (as-prepared ERGO) to 176.5 F cm–3 and 6.02 Wh cm–3 (ERGO compressed at 20 tons), respectively. The ERGOs also exhibited long-term electrochemical stability with a capacitance retention in the range of approximately 79–90% after 10 000 cycles. Lastly, we believe that these high packing density ERGOs are promising for real-world energy storage devices for which scalable, cost-effective manufacturing is of significance and for which space constraints are paramount.

  11. Reduced graphene oxide hydrogels deposited in nickel foam for supercapacitor applications: Toward high volumetric capacitance

    DOE PAGES

    Pham, Viet Hung; Dickerson, James H.

    2016-02-21

    Graphene hydrogels have been considered as ideal materials for high-performance supercapacitors. However, their low volumetric capacitance significantly limits its real application. In this study, we report an environment-friendly and scalable method to prepare high packing density, electrochemically reduced graphene oxide hydrogels (ERGO) for supercapacitor application by the electrophoretic deposition of graphene oxide onto nickel foam, followed by the electrochemical reduction and hydraulic compression of the deposited materials. The as-prepared ERGO on nickel foam was hydraulic compressed up to 20 tons, resulting in an increase of the packing density of ERGO from 0.0098 to 1.32 g cm–3. Consequently, the volumetric capacitancemore » and volumetric energy density of ERGOs greatly increased from 1.58 F cm–3 and 0.053 Wh cm–3 (as-prepared ERGO) to 176.5 F cm–3 and 6.02 Wh cm–3 (ERGO compressed at 20 tons), respectively. The ERGOs also exhibited long-term electrochemical stability with a capacitance retention in the range of approximately 79–90% after 10 000 cycles. Lastly, we believe that these high packing density ERGOs are promising for real-world energy storage devices for which scalable, cost-effective manufacturing is of significance and for which space constraints are paramount.« less

  12. Lightweight, multifunctional polyetherimide/graphene@Fe3O4 composite foams for shielding of electromagnetic pollution.

    PubMed

    Shen, Bin; Zhai, Wentao; Tao, Mimi; Ling, Jianqiang; Zheng, Wenge

    2013-11-13

    Novel high-performance polyetherimide (PEI)/graphene@Fe3O4 (G@Fe3O4) composite foams with flexible character and low density of about 0.28-0.4 g/cm(3) have been developed by using a phase separation method. The obtained PEI/G@Fe3O4 foam with G@Fe3O4 loading of 10 wt % exhibited excellent specific EMI shielding effectiveness (EMI SE) of ~41.5 dB/(g/cm(3)) at 8-12 GHz. Moreover, most the applied microwave was verified to be absorbed rather than being reflected back, resulting from the improved impedance matching, electromagnetic wave attenuation, as well as multiple reflections. Meanwhile, the resulting foams also possessed a superparamagnetic behavior and low thermal conductiviy of 0.042-0.071 W/(m K). This technique is fast, highly reproducible, and scalable, which may facilitate the commercialization of such composite foams and generalize the use of them as EMI shielding materials in the fields of spacecraft and aircraft.

  13. Thermally insulating and fire-retardant lightweight anisotropic foams based on nanocellulose and graphene oxide.

    PubMed

    Wicklein, Bernd; Kocjan, Andraž; Salazar-Alvarez, German; Carosio, Federico; Camino, Giovanni; Antonietti, Markus; Bergström, Lennart

    2015-03-01

    High-performance thermally insulating materials from renewable resources are needed to improve the energy efficiency of buildings. Traditional fossil-fuel-derived insulation materials such as expanded polystyrene and polyurethane have thermal conductivities that are too high for retrofitting or for building new, surface-efficient passive houses. Tailored materials such as aerogels and vacuum insulating panels are fragile and susceptible to perforation. Here, we show that freeze-casting suspensions of cellulose nanofibres, graphene oxide and sepiolite nanorods produces super-insulating, fire-retardant and strong anisotropic foams that perform better than traditional polymer-based insulating materials. The foams are ultralight, show excellent combustion resistance and exhibit a thermal conductivity of 15 mW m(-1) K(-1), which is about half that of expanded polystyrene. At 30 °C and 85% relative humidity, the foams retained more than half of their initial strength. Our results show that nanoscale engineering is a promising strategy for producing foams with excellent properties using cellulose and other renewable nanosized fibrous materials.

  14. Thermally insulating and fire-retardant lightweight anisotropic foams based on nanocellulose and graphene oxide

    NASA Astrophysics Data System (ADS)

    Wicklein, Bernd; Kocjan, Andraž; Salazar-Alvarez, German; Carosio, Federico; Camino, Giovanni; Antonietti, Markus; Bergström, Lennart

    2015-03-01

    High-performance thermally insulating materials from renewable resources are needed to improve the energy efficiency of buildings. Traditional fossil-fuel-derived insulation materials such as expanded polystyrene and polyurethane have thermal conductivities that are too high for retrofitting or for building new, surface-efficient passive houses. Tailored materials such as aerogels and vacuum insulating panels are fragile and susceptible to perforation. Here, we show that freeze-casting suspensions of cellulose nanofibres, graphene oxide and sepiolite nanorods produces super-insulating, fire-retardant and strong anisotropic foams that perform better than traditional polymer-based insulating materials. The foams are ultralight, show excellent combustion resistance and exhibit a thermal conductivity of 15 mW m-1 K-1, which is about half that of expanded polystyrene. At 30 °C and 85% relative humidity, the foams retained more than half of their initial strength. Our results show that nanoscale engineering is a promising strategy for producing foams with excellent properties using cellulose and other renewable nanosized fibrous materials.

  15. Computational investigations and grid refinement study of 3D transient flow in a cylindrical tank using OpenFOAM

    NASA Astrophysics Data System (ADS)

    Mohd Sakri, F.; Mat Ali, M. S.; Sheikh Salim, S. A. Z.

    2016-10-01

    The study of physic fluid for a liquid draining inside a tank is easily accessible using numerical simulation. However, numerical simulation is expensive when the liquid draining involves the multi-phase problem. Since an accurate numerical simulation can be obtained if a proper method for error estimation is accomplished, this paper provides systematic assessment of error estimation due to grid convergence error using OpenFOAM. OpenFOAM is an open source CFD-toolbox and it is well-known among the researchers and institutions because of its free applications and ready to use. In this study, three types of grid resolution are used: coarse, medium and fine grids. Grid Convergence Index (GCI) is applied to estimate the error due to the grid sensitivity. A monotonic convergence condition is obtained in this study that shows the grid convergence error has been progressively reduced. The fine grid has the GCI value below 1%. The extrapolated value from Richardson Extrapolation is in the range of the GCI obtained.

  16. Single-step One-pot Synthesis of Graphene Foam/TiO2 Nanosheet Hybrids for Effective Water Treatment

    NASA Astrophysics Data System (ADS)

    Wang, Weilin; Wang, Zhaofeng; Liu, Jingjing; Zhang, Zhengguo; Sun, Luyi

    2017-03-01

    Millions of tons of wastewater containing both inorganic and organic pollutants are generated every day, leading to significant social, environmental, and economic issues. Herein, we designed a graphene foam/TiO2 nanosheet hybrid, which is able to effectively remove both chromium (VI) cations and organic pollutants simultaneously. This graphene foam/TiO2 nanosheet hybrid was synthesized via a facile single-step one-pot hydrothermal method. The structure of the hybrid was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The hybrid was evaluated for both chromium (VI) and organic pollutants (using methyl blue (MB) as an example) removal, and the removal mechanism was also investigated. During water treatment, graphene and TiO2 nanosheets function complimentarily, leading to a significant synergy. The hybrid exhibited outstanding chromium (VI) and MB removal capacity, much superior to the performance of the individual pure TiO2 sheets or pure graphene foam. The hybrid could also be easily separated after water treatment, and exhibited excellent recycle stability. Considering the very facile synthesis of this graphene foam/TiO2 nanosheet hybrid, and its excellent water treatment performance and recycle stability, such a hybrid is promising for large scale production for practical applications where both chromium (VI) cations and organic dyes are the main pollutants.

  17. Single-step One-pot Synthesis of Graphene Foam/TiO2 Nanosheet Hybrids for Effective Water Treatment

    PubMed Central

    Wang, Weilin; Wang, Zhaofeng; Liu, Jingjing; Zhang, Zhengguo; Sun, Luyi

    2017-01-01

    Millions of tons of wastewater containing both inorganic and organic pollutants are generated every day, leading to significant social, environmental, and economic issues. Herein, we designed a graphene foam/TiO2 nanosheet hybrid, which is able to effectively remove both chromium (VI) cations and organic pollutants simultaneously. This graphene foam/TiO2 nanosheet hybrid was synthesized via a facile single-step one-pot hydrothermal method. The structure of the hybrid was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The hybrid was evaluated for both chromium (VI) and organic pollutants (using methyl blue (MB) as an example) removal, and the removal mechanism was also investigated. During water treatment, graphene and TiO2 nanosheets function complimentarily, leading to a significant synergy. The hybrid exhibited outstanding chromium (VI) and MB removal capacity, much superior to the performance of the individual pure TiO2 sheets or pure graphene foam. The hybrid could also be easily separated after water treatment, and exhibited excellent recycle stability. Considering the very facile synthesis of this graphene foam/TiO2 nanosheet hybrid, and its excellent water treatment performance and recycle stability, such a hybrid is promising for large scale production for practical applications where both chromium (VI) cations and organic dyes are the main pollutants. PMID:28251998

  18. Single-step One-pot Synthesis of Graphene Foam/TiO2 Nanosheet Hybrids for Effective Water Treatment.

    PubMed

    Wang, Weilin; Wang, Zhaofeng; Liu, Jingjing; Zhang, Zhengguo; Sun, Luyi

    2017-03-02

    Millions of tons of wastewater containing both inorganic and organic pollutants are generated every day, leading to significant social, environmental, and economic issues. Herein, we designed a graphene foam/TiO2 nanosheet hybrid, which is able to effectively remove both chromium (VI) cations and organic pollutants simultaneously. This graphene foam/TiO2 nanosheet hybrid was synthesized via a facile single-step one-pot hydrothermal method. The structure of the hybrid was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The hybrid was evaluated for both chromium (VI) and organic pollutants (using methyl blue (MB) as an example) removal, and the removal mechanism was also investigated. During water treatment, graphene and TiO2 nanosheets function complimentarily, leading to a significant synergy. The hybrid exhibited outstanding chromium (VI) and MB removal capacity, much superior to the performance of the individual pure TiO2 sheets or pure graphene foam. The hybrid could also be easily separated after water treatment, and exhibited excellent recycle stability. Considering the very facile synthesis of this graphene foam/TiO2 nanosheet hybrid, and its excellent water treatment performance and recycle stability, such a hybrid is promising for large scale production for practical applications where both chromium (VI) cations and organic dyes are the main pollutants.

  19. Simultaneous optimization of surface chemistry and pore morphology of 3D graphene-sulfur cathode via multi-ion modulation

    NASA Astrophysics Data System (ADS)

    Wang, Jian; Cheng, Shuang; Li, Wanfei; Zhang, Su; Li, Hongfei; Zheng, Zhaozhao; Li, Fujin; Shi, Liyi; Lin, Hongzhen; Zhang, Yuegang

    2016-07-01

    Lithium/sulfur (Li/S) battery is a promising next-generation energy storage system owing to its high theoretical energy density. However, for practical use there remains some key problems to be solved, such as low active material utilization and rapid capacity fading, especially at high areal sulfur loadings. Here, we report a facile one-pot method to prepare porous three-dimensional nitrogen, sulfur-codoped graphene through hydrothermal reduction of graphene oxide with multi-ion mixture modulation. We show solid evidence that the results of multi-ion mixture modulation can not only improve the surface affinity of the nanocarbons to polysulfides, but also alter their assembling manner and render the resultant 3D network a more favorable pore morphology for accommodating and confining sulfur. It also had an excellent rate performance and cycling stability, showing an initial capacity of 1304 mA h g-1 at 0.05C, 613 mA h g-1 at 5C and maintaining a reversible capacity of 462 mA h g-1 after 1500 cycles at 2C with capacity fading as low as 0.028% per cycle. Moreover, a high areal capacity of 5.1 mA h cm-2 at 0.2C is achieved at an areal sulfur loading of 6.3 mg cm-2, which are the best values reported so far for dual-doped sulfur cathodes.

  20. Numerical analysis of a 3D optical sensor based on single mode fiber to multimode interference graphene design

    NASA Astrophysics Data System (ADS)

    Mutter, Kussay N.; Jafri, Zubir M.; Tan, Kok Chooi

    2016-04-01

    In this paper, the simulation and design of a waveguide for water turbidity sensing are presented. The structure of the proposed sensor uses a 2x2 array of multimode interference (MMI) coupler based on micro graphene waveguide for high sensitivity. The beam propagation method (BPM) are used to efficiently design the sensor structure. The structure is consist of an array of two by two elements of sensors. Each element has three sections of single mode for field input tapered to MMI as the main core sensor without cladding which is graphene based material, and then a single mode fiber as an output. In this configuration MMI responses to any change in the environment. We validate and present the results by implementing the design on a set of sucrose solution and showing how these samples lead to a sensitivity change in the sensor based on the MMI structures. Overall results, the 3D design has a feasible and effective sensing by drawing topographical distribution of suspended particles in the water.

  1. A facile and green strategy for preparing newly-designed 3D graphene/gold film and its application in highly efficient electrochemical mercury assay.

    PubMed

    Shi, Lei; Wang, Yan; Ding, Shiming; Chu, Zhenyu; Yin, Yu; Jiang, Danfeng; Luo, Jingyi; Jin, Wanqin

    2017-03-15

    In this work, we report a facile and green strategy for in situ and one step preparation of a novel 3D graphene/gold (G/Au) film. Triggering with unique driving force from hydrothermal growth, a 3D interlaced graphene framework with hierarchically porous structures was directly attached on a gold substrate pretreated with a self-assembled monolayer. Simultaneously, highly dispersive Au nanoparticles with tunable morphologies were anchored on the framework utilizing generated graphene as an endogenous reductant. Newly-designed 3D G/Au film possessed excellent properties of significantly large specific area, good electrical conductivity, high structure stability and substrate binding strength, etc. As a paradigm, an electrochemical Hg(2+) biosensor was constructed on 3D G/Au film, in which an exonuclease III-assisted target recycling was introduced. Impressively, an ultralow detection limit of 50 aM (S/N=3), a wide linear range from 0.1 fM to 0.1μM, a high selectivity and a good reliability for Hg(2+) assay in real water and serum samples were realized using prepared biosensor. It is highly envisioned that this work opens the door towards simply fabricating varying types of 3D graphene based hybrid films, and such G/Au film will have widespread applications in electroanalysis and electrocatalysis.

  2. The hybridizations of cobalt 3 d bands with the electron band structure of the graphene/cobalt interface on a tungsten substrate

    NASA Astrophysics Data System (ADS)

    Hwang, Jinwoong; Hwang, Choongyu; Chung, Nak-Kwan; N'Diaye, A. D.; Schmid, A. K.; Denlinger, Jonathan

    2016-08-01

    The interface between graphene and a ferromagnetic substrate has attracted recent research interests due to its potential for spintronic applications. We report an angle-resolved photoemission spectroscopy study on the interface between graphene and cobalt epitaxially grown on a tungsten substrate. We find that the electron band structure of the interface exhibits clear discontinuities at the crossing points with cobalt 3 d bands. These observations indicate strong hybridizations between the electronic states in the interface and provide an important clue to understand the intriguing electromagnetic properties of the graphene/ferromagnet interface.

  3. Ni nanoparticles supported on graphene layers: An excellent 3D electrode for hydrogen evolution reaction in alkaline solution

    NASA Astrophysics Data System (ADS)

    Wang, Lixin; Li, Yao; Xia, Meirong; Li, Zhiping; Chen, Zhouhao; Ma, Zhipeng; Qin, Xiujuan; Shao, Guangjie

    2017-04-01

    Metal Ni is a plentiful resource that can actively split water toward hydrogen evolution reaction (HER) in alkaline solution, but exploiting high-efficiency Ni-based composite catalysts is still a significant assignment. Therefore, we design a catalytic material with one-step approach to co-electrodeposit Ni nanoparticles and reduced graphene oxide (rGO) sheets on a three-dimensional Ni foam. When the carbon content existed in Ni-rGO composite catalyst is 3.335 at%, the catalyst exhibits excellent activity on HER with a low Tafel slope (b = 77 mV dec-1), a high exchange current density (j0 = 3.408 mA cm-2), small overpotentials of only 36, 129, and 183 mV to drive 10, 60, and 100 mA cm-2 respectively, and high stability under the different current densities. Such remarkable hydrogen evolution performance is attributed to good electrical conductivity, large specific surface area and harmonious synergistic effect between Ni particles and rGO sheets. In addition, density functional theory (DFT) calculations explain that Ni-rGO composite material presents superior interfacial activity in adsorption/desorption of H* compared with pure Ni and rGO sheet.

  4. Lightweight, Superelastic, and Mechanically Flexible Graphene/Polyimide Nanocomposite Foam for Strain Sensor Application.

    PubMed

    Qin, Yuyang; Peng, Qingyu; Ding, Yujie; Lin, Zaishan; Wang, Chunhui; Li, Ying; Xu, Fan; Li, Jianjun; Yuan, Ye; He, Xiaodong; Li, Yibin

    2015-09-22

    The creation of superelastic, flexible three-dimensional (3D) graphene-based architectures is still a great challenge due to structure collapse or significant plastic deformation. Herein, we report a facile approach of transforming the mechanically fragile reduced graphene oxide (rGO) aerogel into superflexible 3D architectures by introducing water-soluble polyimide (PI). The rGO/PI nanocomposites are fabricated using strategies of freeze casting and thermal annealing. The resulting monoliths exhibit low density, excellent flexibility, superelasticity with high recovery rate, and extraordinary reversible compressibility. The synergistic effect between rGO and PI endows the elastomer with desirable electrical conductivity, remarkable compression sensitivity, and excellent durable stability. The rGO/PI nanocomposites show potential applications in multifunctional strain sensors under the deformations of compression, bending, stretching, and torsion.

  5. Spatial mobility fluctuation induced giant linear magnetoresistance in multilayered graphene foam

    NASA Astrophysics Data System (ADS)

    Li, Peng; Zhang, Qiang; He, Xin; Ren, Wencai; Cheng, Hui-Ming; Zhang, Xi-xiang

    2016-07-01

    Giant, positive, and near-temperature-independent linear magnetoresistance (LMR), as large as 340%, was observed in graphene foam with a three-dimensional flexible network. Careful analysis of the magnetoresistance revealed that Shubnikov-de Haas (SdH) oscillations occurred at low temperatures and decayed with increasing temperature. The average classical mobility ranged from 300 (2 K) to 150 (300 K) c m2V-1s-1 , which is much smaller than that required by the observed SdH oscillations. To understand the mechanism behind the observation, we performed the same measurements on the microsized graphene sheets that constitute the graphene foam. Much more pronounced SdH oscillations superimposed on the LMR background were observed in these microscaled samples, which correspond to a quantum mobility as high as 26 ,500 c m2V-1s-1 . Moreover, the spatial mobility fluctuated significantly from 64 ,200 c m2V-1s-1 to 1370 c m2V-1s-1 , accompanied by a variation of magnetoresistance from near 20,000% to less than 20%. The presence of SdH oscillations actually excludes the possibility that the observed LMR originated from the extreme quantum limit, because this would demand all electrons to be in the first Landau level. Instead, we ascribe the large LMR to the second case of the classical Parish and Littlewood model, in which spatial mobility fluctuation dominates electrical transport. This is an experimental confirmation of the Parish and Littlewood model by measuring the local mobility randomly (by measuring the microsized graphene sheets) and finding the spatial mobility fluctuation.

  6. Toward 3D graphene oxide gels based adsorbents for high-efficient water treatment via the promotion of biopolymers.

    PubMed

    Cheng, Chong Sage; Deng, Jie; Lei, Bei; He, Ai; Zhang, Xiang; Ma, Lang; Li, Shuang; Zhao, Changsheng

    2013-12-15

    Recent studies showed that graphene oxide (GO) presented high adsorption capacities to various water contaminants. However, the needed centrifugation after adsorption and the potential biological toxicity of GO restricted its applications in wastewater treatment. In this study, a facile method is provided by using biopolymers to mediate and synthesize 3D GO based gels. The obtained hybrid gels present well-defined and interconnected 3D porous network, which allows the adsorbate molecules to diffuse easily into the adsorbent. The adsorption experiments indicate that the obtained porous GO-biopolymer gels can efficiently remove cationic dyes and heavy metal ions from wastewater. Methylene blue (MB) and methyl violet (MV), two cationic dyes, are chosen as model adsorbates to investigate the adsorption capability and desorption ratio; meanwhile, the influence of contacting time, initial concentration, and pH value on the adsorption capacity of the prepared GO-biopolymer gels are also studied. The GO-biopolymer gels displayed an adsorption capacity as high as 1100 mg/g for MB dye and 1350 mg/g for MV dye, respectively. Furthermore, the adsorption kinetics and isotherms of the MB were studied in details. The experimental data of MB adsorption fitted well with the pseudo-second-order kinetic model and the Langmuir isotherm, and the results indicated that the adsorption process was controlled by the intraparticle diffusion. Moreover, the adsorption data revealed that the porous GO-biopolymer gels showed good selective adsorbability to cationic dyes and metal ions.

  7. Synthesis of Ni3S2 nanotube arrays on nickel foam by catalysis of thermal reduced graphene for hydrogen evolution reaction

    NASA Astrophysics Data System (ADS)

    Jinlong, Lv; Miura, Hideo; Meng, Yang; Tongxiang, Liang

    2017-03-01

    The thermal reduced graphene oxide deposition on nickel foam was successfully synthesized by ultrasonic and subsequent thermal reduction process. Ultrathin mesoporous Ni3S2 was formed on the bare nickel foam after hydrothermal process, while Ni3S2 nanotube arrays were formed on the surface of nickel foam with the thermal reduced graphene oxide due to catalysis action of thermal reduced graphene oxide. The resulting Ni3S2 nanotube arrays exhibited higher catalytic activity than ultrathin mesoporous Ni3S2 for hydrogen evolution reaction. In addition, and excellent stability was also obtained in Ni3S2 nanotube arrays.

  8. Composite System of Graphene Oxide and Polypeptide Thermogel As an Injectable 3D Scaffold for Adipogenic Differentiation of Tonsil-Derived Mesenchymal Stem Cells.

    PubMed

    Patel, Madhumita; Moon, Hyo Jung; Ko, Du Young; Jeong, Byeongmoon

    2016-03-02

    As two-dimensional (2D) nanomaterials, graphene (G) and graphene oxide (GO) have evolved into new platforms for biomedical research as biosensors, imaging agents, and drug delivery carriers. In particular, the unique surface properties of GO can be an important tool in modulating cellular behavior and various biological sequences. Here, we report that a composite system of graphene oxide/polypeptide thermogel (GO/P), prepared by temperature-sensitive sol-to-gel transition of a GO-suspended poly(ethylene glycol)-poly(L-alanine) (PEG-PA) aqueous solution significantly enhances the expression of adipogenic biomarkers, including PPAR-γ, CEBP-α, LPL, AP2, ELOVL3, and HSL, compared to both a pure hydrogel system and a composite system of G/P, graphene-incorporated hydrogel. We prove that insulin, an adipogenic differentiation factor, preferentially adhered to GO, is supplied to the incorporated stem cells in a sustained manner over the three-dimensional (3D) cell culture period. On the other hand, insulin is partially denatured in the presence of G and interferes with the adipogenic differentiation of the stem cells. The study suggests that a 2D/3D composite system is a promising platform as a 3D cell culture matrix, where the surface properties of 2D materials in modulating the fates of the stem cells are effectively transcribed in a 3D culture system.

  9. Anchoring Nitrogen-Doped TiO2 Nanocrystals on Nitrogen-Doped 3D Graphene Frameworks for Enhanced Lithium Storage.

    PubMed

    Liu, Xiao-Wu; Yang, Zhen-Zhong; Pan, Fu-Sen; Gu, Lin; Yu, Yan

    2017-02-03

    An advanced architecture design of nitrogen-doped TiO2 anchored on nitrogen-doped 3D graphene framework composites (denoted as N-TiO2 /N-3D GFs) have been fabricated by a facile template process and further NH3 treatment. The 3D graphene framework allows the electrolyte to penetrate into the inverse opal structure, and possesses high electronic conductivity. The close contact between the N-TiO2 and the graphene suppresses the growth and aggregation of TiO2 nanoparticles during heating process, leading to decreased Li(+) diffusion length. The N-doping in both TiO2 and the graphene matrix could improve the electronic conductivity on the TiO2 particle surface and between adjacent particles. As expected, when used as an anode for Li-ion batteries (LIBs), the N-TiO2 /N-3D GFs composite delivers an excellent reversible capacity of 165 mA h g(-1) after 200 cycles at 100 mA g(-1) and an outstanding rate capability of 114 mA h g(-1) after 1000 cycles at 1 Ag(-1) . With rational design, this strategy could be extended to other electrode materials that may hold great promise for the development of high energy storage systems.

  10. New strategy to rescue the inhibition of osteogenesis of human bone marrow-derived mesenchymal stem cells under oxidative stress: combination of vitamin C and graphene foams

    PubMed Central

    Wang, Feng; Lu, Ye; Yin, Peipei; Jiang, Chaolai; Liu, Yingjie; Li, Hua; Yu, Xiaowei; Sun, Yuqiang

    2016-01-01

    To rescue the oxidative stress induced inhibition of osteogenesis, vitamin C (VC) was chemically modified onto three-dimensional graphene foams (3D GFs), then their regulation on osteogenesis of human bone marrow-derived mesenchymal stem cells (BM-MSCs) was studied. Combined action of VC + GF significantly decreased H2O2-induced oxidative stress, and rescued H2O2-inhibited cell viability, differentiation and osteogenesis of BM-MSCs in vitro. Further studies revealed that Wnt pathway may be involved in this protection of osteogenesis. Furthermore, an in vivo mouse model of BM-MSCs transplantation showed that VC + GF remarkably rescued oxidative stress inhibited calcium content and bone formation. The combination of VC and GF exhibited more pronounced protective effects against oxidative stress induced inhibition of osteogenesis, compared to monotherapy of VC or GF. Our study proposed a new strategy in stem cell-based therapies for treating bone diseases. PMID:27713129

  11. 3D well-interconnected NiO-graphene-carbon nanotube nanohybrids as high-performance anode materials for Li-ion batteries

    NASA Astrophysics Data System (ADS)

    Zhang, Zhifeng; Zhang, Xia; You, Xiaolong; Zhang, Mengyuan; Walle, Maru Dessie; Wang, Juan; Li, Yajuan; Liu, You-Nian

    2016-08-01

    3D carbon scaffold built from carbon nanotubes (CNTs) and graphene exhibits the synergistic effects in electronic conductivity and buffers the structural strain of materials. In this paper, NiO-graphene-carbon nanotubes (NiO-G-CNTs) nanohybrids were prepared via a facile hydrothermal-thermal decomposition process. The as-prepared ternary component nanohybrids exhibit high reversible specific capacity, improved cycling stability, and excellent rate capability, compared to those of NiO-graphene hybrids and pure NiO. The NiO-G-CNT electrode reveals a specific capacity of 858.1 mA h g-1 after 50 cycles at a current density of 100 mA g-1. At a higher current density of 1000 mA g-1, it still reveals a specific capacity of 676 mA h g-1 after 40 cycles. This outstanding electrochemical performance is attributed to its special 3D network structures, where the NiO nanoparticles are well distributed on the surface of graphene sheets, with the CNTs interwoven between individual graphene sheets. This special structure effectively prevents the restacking of graphene sheets and affords an easy route for the transport of electrons and ions.

  12. Growth of hierarchical 3D mesoporous NiSix /NiCo2 O4 core/shell heterostructures on nickel foam for lithium-ion batteries.

    PubMed

    Zhang, Qiaobao; Chen, Huixin; Wang, Jiexi; Xu, Daguo; Li, Xinhai; Yang, Yong; Zhang, Kaili

    2014-08-01

    We demonstrate the facile and well-controlled design and fabrication of heterostructured and hierarchical 3D mesoporous NiSix /NiCo2 O4 core/shell nanowire arrays on nickel foam through a facile chemical vapor deposition (CVD) technique combined with a simple but powerful chemical bath deposition (CBD) technique. The smart hybridization of NiCo2 O4 and NiSix nanostructures results in an intriguing mesoporous hierarchical core/shell nanowire-array architecture. The nanowire arrays demonstrate enhanced electrochemical performance as binder- and conductive-agent-free electrodes for lithium ion batteries (LIBs) with excellent capacity retention and high rate capability on cycling. The electrodes can maintain a high reversible capacity of 1693 mA h g(-1) after 50 cycles at 20 mA g(-1) . Given the outstanding performance and simple, efficient, cost-effective fabrication, we believe that these 3D NiSix /NiCo2 O4 core/shell heterostructured arrays have great potential application in high-performance LIBs.

  13. SnO2@PANI Core-Shell Nanorod Arrays on 3D Graphite Foam: A High-Performance Integrated Electrode for Lithium-Ion Batteries.

    PubMed

    Zhang, Feng; Yang, Chengkai; Gao, Xin; Chen, Shuai; Hu, Yiran; Guan, Huanqin; Ma, Yurong; Zhang, Jin; Zhou, Henghui; Qi, Limin

    2017-03-22

    The rational design and controllable fabrication of electrode materials with tailored structures and superior performance is highly desirable for the next-generation lithium ion batteries (LIBs). In this work, a novel three-dimensional (3D) graphite foam (GF)@SnO2 nanorod arrays (NRAs)@polyaniline (PANI) hybrid architecture was constructed via solvothermal growth followed by electrochemical deposition. Aligned SnO2 NRAs were uniformly grown on the surface of GF, and a PANI shell with a thickness of ∼40 nm was coated on individual SnO2 nanorods, forming a SnO2@PANI core-shell structure. Benefiting from the synergetic effect of 3D GF with large surface area and high conductivity, SnO2 NRAs offering direct pathways for electrons and lithium ions, and the conductive PANI shell that accommodates the large volume variation of SnO2, the binder-free, integrated GF@SnO2 NRAs@PANI electrode for LIBs exhibited high capacity, excellent rate capability, and good electrochemical stability. A high discharge capacity of 540 mAh g(-1) (calculated by the total mass of the electrode) was achieved after 50 cycles at a current density of 500 mA g(-1). Moreover, the electrode demonstrated superior rate performance with a discharge capacity of 414 mAh g(-1) at a high rate of 3 A g(-1).

  14. Assessing the improved performance of freestanding, flexible graphene and carbon nanotube hybrid foams for lithium ion battery anodes

    NASA Astrophysics Data System (ADS)

    Cohn, Adam P.; Oakes, Landon; Carter, Rachel; Chatterjee, Shahana; Westover, Andrew S.; Share, Keith; Pint, Cary L.

    2014-04-01

    We demonstrate the fabrication of three-dimensional freestanding foams of hybrid graphene-single-walled carbon nanotube nanomanufactured materials with reversible capacities of 2640 mA h g-1 at 0.186 A g-1 and 236 mA h g-1 at 27.9 A g-1. The Li storage behavior of this material is compared against other nanostructures in similar flexible foam platforms including graphene, ultra-thin graphite, and single-walled carbon nanotubes (SWNTs), and we elucidate the improved hybrid material performance due to the decoupling of lithium storage reaction energetics dictated by the SWNTs from the total storage capacity of the hybrid material. This work demonstrates a route to develop mechanically robust all-carbon electrodes with the potential for reversible Li-ion storage capacity approaching silicon, power capability of the best supercapacitors, and based on a material simultaneously usable as a charge collector and anode.We demonstrate the fabrication of three-dimensional freestanding foams of hybrid graphene-single-walled carbon nanotube nanomanufactured materials with reversible capacities of 2640 mA h g-1 at 0.186 A g-1 and 236 mA h g-1 at 27.9 A g-1. The Li storage behavior of this material is compared against other nanostructures in similar flexible foam platforms including graphene, ultra-thin graphite, and single-walled carbon nanotubes (SWNTs), and we elucidate the improved hybrid material performance due to the decoupling of lithium storage reaction energetics dictated by the SWNTs from the total storage capacity of the hybrid material. This work demonstrates a route to develop mechanically robust all-carbon electrodes with the potential for reversible Li-ion storage capacity approaching silicon, power capability of the best supercapacitors, and based on a material simultaneously usable as a charge collector and anode. Electronic supplementary information (ESI) available: ESI is available that includes (i) SEM and photographs of ultra-thin graphite foams, (ii) Raman

  15. Fabrication of a novel dual mode cholesterol biosensor using titanium dioxide nanowire bridged 3D graphene nanostacks.

    PubMed

    Komathi, S; Muthuchamy, N; Lee, K-P; Gopalan, A-I

    2016-10-15

    Herein, we fabricated a novel electrochemical-photoelectrochemical (PEC) dual-mode cholesterol biosensor based on graphene (G) sheets interconnected-graphene embedded titanium nanowires (TiO2(G)-NWs) 3D nanostacks (designated as G/Ti(G) 3DNS) by exploiting the beneficial characteristics of G and TiO2-NWs to achieve good selectivity and high sensitivity for cholesterol detection. The G/Ti(G) 3DNS was fabricated by the reaction between functionalized G and TiO2(G)-NWs. Cholesterol oxidase (ChOx) was subsequently immobilized in to G/Ti(G) 3DNS using chitosan (CS) as the binder and the dual mode G/Ti(G) 3DNS/CS/ChOx biosensor was fabricated. The electro-optical properties of the G/Ti(G) 3DNS/CS/ChOx bioelectrode were characterized by cyclic voltammetry and UV-vis diffuse reflection spectroscopy. The cyclic voltammetry of immobilized ChOx showed a pair of well-defined redox peaks indicating direct electron transfer (DET) of ChOx. The amperometric reduction peak current (at -0.05V) linearly increased with increase in cholesterol concentration. The G/Ti(G) 3DNS/CS/ChOx bioelectrode was selective to cholesterol with a remarkable sensitivity (3.82μA/cm(2)mM) and a lower detection limit (6μM). Also, G/Ti(G) 3DNS/CS/ChOx functioned as photoelectrode and exhibited selective detection of cholesterol under a low bias voltage and light irradiation. Kinetic parameters, reproducibility, repeatability, storage stability and effect of temperature and pH were evaluated. We envisage that G/Ti(G) 3DNS with its prospective characteristics, would be a promising material for wide range of biosensing applications.

  16. Optical conductivity renormalization of graphene on SrTiO 3 due to resonant excitonic effects mediated by Ti 3 d orbitals

    NASA Astrophysics Data System (ADS)

    Gogoi, Pranjal Kumar; Trevisanutto, Paolo E.; Yang, Ming; Santoso, Iman; Asmara, Teguh Citra; Terentjevs, Aleksandrs; Della Sala, Fabio; Breese, Mark B. H.; Venkatesan, T.; Feng, Yuan Ping; Loh, Kian Ping; Neto, Antonio H. Castro; Rusydi, Andrivo

    2015-01-01

    We present evidence of a drastic renormalization of the optical conductivity of graphene on SrTiO 3 resulting in almost full transparency in the ultraviolet region. These findings are attributed to resonant excitonic effects further supported by ab initio Bethe-Salpeter equation and density functional theory calculations. The (π ,π *) orbitals of graphene and Ti-3 d t2 g orbitals of SrTiO 3 are strongly hybridized and the interactions of electron-hole states residing in those orbitals play dominant role in the graphene optical conductivity. These interactions are present much below the optical band gap of bulk SrTiO 3. These results open a possibility of manipulating interaction strengths in graphene via d orbitals, which could be crucial for optical applications.

  17. Electrodeposition of palladium and reduced graphene oxide nanocomposites on foam-nickel electrode for electrocatalytic hydrodechlorination of 4-chlorophenol.

    PubMed

    Liu, Yong; Liu, Lan; Shan, Jun; Zhang, Jingdong

    2015-06-15

    A high-performance palladium (Pd) and reduced graphene oxide (RGO) composite electrode was prepared on foam-nickel (foam-Ni) via two-step electrodeposition processes. The scanning electron microscopic (SEM) observation showed that the obtained Pd/RGO/foam-Ni composite electrode displayed a uniform and compact morphology. The X-ray diffraction (XRD) and X-ray photoelectron spectroscopic (XPS) analysis confirmed the successful deposition of Pd and RGO on nickel substrate. The cyclic voltammetric (CV) measurements indicated that the presence of RGO greatly enhanced the active surface area of Pd particles deposited on foam-Ni. The as-deposited Pd/RGO/foam-Ni electrode was applied to electrocatalytic hydrodechlorination (ECH) of 4-chlorophenol (4-CP). Various factors influencing the dechlorination of 4-CP such as dechlorination current, initial concentration of 4-CP, Na2SO4 concentration and initial pH were systematically investigated. The thermodynamic analysis showed that the dechlorination reaction of 4-CP at different temperatures followed the first-order kinetics and the activation energy for 4-CP dechlorination on Pd/RGO/foam-Ni electrode was calculated to be 51.96 kJ mol(-1). Under the optimum conditions, the dechlorination efficiency of 4-CP could reach 100% after 60-min ECH treatment. Moreover, the prepared Pd/RGO/foam-Ni composite electrode showed good stability for recycling utilization in ECH of 4-CP.

  18. ZnO template strategy for the synthesis of 3D interconnected graphene nanocapsules from coal tar pitch as supercapacitor electrode materials

    NASA Astrophysics Data System (ADS)

    He, Xiaojun; Li, Xiaojing; Ma, Hao; Han, Jiufeng; Zhang, Hao; Yu, Chang; Xiao, Nan; Qiu, Jieshan

    2017-02-01

    3D interconnected graphene nanocapsules (GNCs) were prepared from diverse aromatic hydrocarbons by a nano-ZnO-template strategy coupled with in-situ KOH activation technique. The as-made graphene networks feature thin carbonaceous shells with well-balanced micropores and mesopores. Such 3D porous networks provide freeways for good electron conduction, short pores for ion fast transport, and abundant micropores for ion adsorption. As the electrodes in supercapacitors, the unique 3D GNCs show a high capacitance of 277 F g-1 at 0.05 A g-1, a good rate performance of 194 F g-1 at 20 A g-1, and an excellent cycle stability with over 97.4% capacitance retention after 15000 cycles in 6 M KOH electrolyte. This synthesis strategy paves a universal way for mass production of 3D graphene materials from diverse aromatic hydrocarbon sources including coal tar pitch and petroleum pitch for high performance supercapacitors as well as support and sorbent.

  19. High performance asymmetric supercapacitor based on molybdenum disulphide/graphene foam and activated carbon from expanded graphite.

    PubMed

    Masikhwa, Tshifhiwa M; Madito, Moshawe J; Bello, Abdulhakeem; Dangbegnon, Julien K; Manyala, Ncholu

    2017-02-15

    Molybdenum disulphide which has a graphene-like single layer structure has excellent mechanical and electrical properties and unique morphology, which might be used with graphene foam as composite in supercapacitor applications. In this work, Molybdenum disulphide (MoS2)/graphene foam (GF) composites with different graphene foam loading were synthesized by the hydrothermal process to improve on specific capacitance of the composites. Asymmetric supercapacitor device was fabricated using the best performing MoS2/GF composite and activated carbon derived from expanded graphite (AEG) as positive and negative electrodes, respectively, in 6M KOH electrolyte. The asymmetric MoS2/GF//AEG device exhibited a maximum specific capacitance of 59Fg(-1) at a current density of 1Ag(-1) with maximum energy and power densities of 16Whkg(-1) and 758Wkg(-1), respectively. The supercapacitor also exhibited a good cyclic stability with 95% capacitance retention over 2000 constant charge-discharge cycles. The results obtained demonstrate the potential of MoS2/GF//AEG as a promising material for electrochemical energy storage application.

  20. A hierarchically structured graphene foam and its potential as a large-scale strain-gauge sensor

    NASA Astrophysics Data System (ADS)

    Kuang, Jun; Liu, Luqi; Gao, Yun; Zhou, Ding; Chen, Zhuo; Han, Baohang; Zhang, Zhong

    2013-11-01

    A hierarchically structured thermal-reduced graphene (ReG) foam with 0.5 S cm-1 electrical conductivity is fabricated from a well-dispersed graphene oxide suspension via a directional freezing method followed by high-temperature thermal treatment. The as-prepared three-dimensional ReG foam has an ordered macroporous honeycomb-like structure with straight and parallel voids in the range of 30 μm to 75 μm separated by cell walls of several tens of nanometers thick. Despite its ultra-low density, the ReG foam has an excellent compression recovery along its in-plane direction. This property of the ReG foam can be attributed to its hierarchically porous structure, as demonstrated by the compression test. The excellent compression recovery and high conductivity provide the ReG foam with exceptional piezoresistive capabilities. The electrical resistance of the ReG foam shows a linearly decreasing trend with compressive strain increments of up to 60%, which cannot be observed in conventional rigid material-based sensors and carbon nanotube-based polymer sensors. Such intriguing linear strain-responsive behavior, along with the fast response time and high thermal stability, makes the ReG foam a promising candidate for strain sensing. We demonstrated that it could be used as a wearable device for real-time monitoring of human health.A hierarchically structured thermal-reduced graphene (ReG) foam with 0.5 S cm-1 electrical conductivity is fabricated from a well-dispersed graphene oxide suspension via a directional freezing method followed by high-temperature thermal treatment. The as-prepared three-dimensional ReG foam has an ordered macroporous honeycomb-like structure with straight and parallel voids in the range of 30 μm to 75 μm separated by cell walls of several tens of nanometers thick. Despite its ultra-low density, the ReG foam has an excellent compression recovery along its in-plane direction. This property of the ReG foam can be attributed to its hierarchically

  1. High Energy Density Asymmetric Supercapacitor Based on NiOOH/Ni3S2/3D Graphene and Fe3O4/Graphene Composite Electrodes

    PubMed Central

    Lin, Tsung-Wu; Dai, Chao-Shuan; Hung, Kuan-Chung

    2014-01-01

    The application of the composite of Ni3S2 nanoparticles and 3D graphene as a novel cathode material for supercapacitors is systematically investigated in this study. It is found that the electrode capacitance increases by up to 111% after the composite electrode is activated by the consecutive cyclic voltammetry scanning in 1 M KOH. Due to the synergistic effect, the capacitance and the diffusion coefficient of electrolyte ions of the activated composite electrode are ca. 3.7 and 6.5 times higher than those of the Ni3S2 electrode, respectively. Furthermore, the activated composite electrode exhibits an ultrahigh specific capacitance of 3296 F/g and great cycling stability at a current density of 16 A/g. To obtain the reasonable matching of cathode/anode electrodes, the composite of Fe3O4 nanoparticles and chemically reduced graphene oxide (Fe3O4/rGO) is synthesized as the anode material. The Fe3O4/rGO electrode exhibits the specific capacitance of 661 F/g at 1 A/g and excellent rate capability. More importantly, an asymmetric supercapacitor fabricated by two different composite electrodes can be operated reversibly between 0 and 1.6 V and obtain a high specific capacitance of 233 F/g at 5 mV/s, which delivers a maximum energy density of 82.5 Wh/kg at a power density of 930 W/kg. PMID:25449978

  2. 3D graphene preparation via covalent amide functionalization for efficient metal-free electrocatalysis in oxygen reduction

    PubMed Central

    Ahmed, Mohammad Shamsuddin; Kim, Young-Bae

    2017-01-01

    3D and porous reduced graphene oxide (rGO) catalysts have been prepared with sp3-hybridized 1,4-diaminobutane (sp3-DABu, rGO-sp3-rGO) and sp2-hybridized 1,4-diaminobenzene (sp2-DABe, rGO-sp2-rGO) through a covalent amidation and have employed as a metal-free electrocatalyst for oxygen reduction reaction (ORR) in alkaline media. Both compounds have used as a junction between functionalized rGO layers to improve electrical conductivity and impart electrocatalytic activity to the ORR resulting from the interlayer charge transfer. The successful amidation and the subsequent reduction in the process of catalyst preparation have confirmed by X-ray photoelectron spectroscopy. A hierarchical porous structure is also confirmed by surface morphological analysis. Specific surface area and thermal stability have increased after successful the amidation by sp3-DABu. The investigated ORR mechanism reveals that both functionalized rGO is better ORR active than nonfunctionalized rGO due to pyridinic-like N content and rGO-sp3-rGO is better ORR active than rGO-sp2-rGO due to higher pyridinic-like N content and π-electron interaction-free interlayer charge transfer. Thus, the rGO-sp3-rGO has proven as an efficient metal-free electrocatalyst with better electrocatalytic activity, stability, and tolerance to the crossover effect than the commercially available Pt/C for ORR. PMID:28240302

  3. High-performance symmetric electrochemical capacitor based on graphene foam and nanostructured manganese oxide

    NASA Astrophysics Data System (ADS)

    Bello, Abdulhakeem; Fashedemi, Omobosede O.; Lekitima, Joel N.; Fabiane, Mopeli; Dodoo-Arhin, David; Ozoemena, Kenneth I.; Gogotsi, Yury; Charlie Johnson, Alan T.; Manyala, Ncholu

    2013-08-01

    We have fabricated a symmetric electrochemical capacitor with high energy and power densities based on a composite of graphene foam (GF) with ˜80 wt% of manganese oxide (MnO2) deposited by hydrothermal synthesis. Raman spectroscopy and X-ray diffraction measurements showed the presence of nanocrystalline MnO2 on the GF, while scanning and transmission electron microscopies showed needle-like manganese oxide coated and anchored onto the surface of graphene. Electrochemical measurements of the composite electrode gave a specific capacitance of 240 Fg-1 at a current density of 0.1 Ag-1 for symmetric supercapacitors using a two-electrode configuration. A maximum energy density of 8.3 Whkg-1 was obtained, with power density of 20 kWkg-1 and no capacitance loss after 1000 cycles. GF is an excellent support for pseudo-capacitive oxide materials such as MnO2, and the composite electrode provided a high energy density due to a combination of double-layer and redox capacitance mechanisms.

  4. Facile Fabrication of 3D Layer-by-layer Graphene-gold Nanorod Hybrid Architecture for Hydrogen Peroxide Based Electrochemical Biosensor

    DTIC Science & Technology

    2015-01-01

    Facile fabrication of 3D layer-by-layer graphene-gold nanorod hybrid architecture for hydrogen peroxide based electrochemical biosensor Chenming Xue...the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/). 1. Introduction Electrochemical biosensors are highly effective in...measurement techniques such as radioisotope tracing, NMR spectroscopy, and microfluorometry assay [12,25,18]. In recent years, electrochemical biosensors

  5. Hydrothermal synthesis of 3D urchin-like Ag/TiO2/reduced graphene oxide composites and its enhanced photocatalytic performance

    NASA Astrophysics Data System (ADS)

    Liu, Yuhuan; Zhou, Yi; Yang, Luyue; Wang, Yutang; Wu, Yiwei; Li, Chaocheng; Lu, Jun

    2016-09-01

    Innovative 3D urchin-like ternary TiO2 composites, which combine Ag nanoparticles with graphene, have been successfully synthesized through a simple hydrothermal method. This process employed nontoxic and mild dihydrate sodium citrate as a reducing agent. During the hydrothermal process, graphene oxide and AgNO3 were reduced to reduced graphene oxide (RGO) and Ag, respectively. Subsequently, they were grown on the surface of rutile TiO2 with a 3D urchin-like microsphere (1.5 μm). The as-prepared 3D urchin-like composites were characterized by X-ray diffraction, SEM and TEM. These techniques were also employed to ensure the morphology of urchin-like and rutile phase of TiO2. FT-IR, Raman spectroscopy and XPS characterization demonstrated the successful reduction in AgNO3 and graphite oxide to metallic Ag and RGO. The UV-visible spectrum of the ternary composite displayed strong absorption in the visible light region, which was attributed to the efficient electron transport of well-dispersed Ag nanoparticles (20-40 nm) and the formation of Ti-O-C bond between graphene and titania. The synthesized urchin-like ternary composite exhibited enhanced photocatalytic activity (98.7 %) for Rhodamine B degradation. This work provides a very convenient chemical route to the scalable production of Ag/TiO2/RGO ternary composite photocatalyst for potential applications in solving the environmental problems and energy issues. Also, the proposed mechanism underlying the photocatalytic degradation of Rhodamine B dyes was discussed.

  6. In Situ Activation of Nitrogen-Doped Graphene Anchored on Graphite Foam for a High-Capacity Anode.

    PubMed

    Ji, Junyi; Liu, Jilei; Lai, Linfei; Zhao, Xin; Zhen, Yongda; Lin, Jianyi; Zhu, Yanwu; Ji, Hengxing; Zhang, Li Li; Ruoff, Rodney S

    2015-08-25

    We report the fabrication of a three-dimensional free-standing nitrogen-doped porous graphene/graphite foam by in situ activation of nitrogen-doped graphene on highly conductive graphite foam (GF). After in situ activation, intimate "sheet contact" was observed between the graphene sheets and the GF. The sheet contact produced by in situ activation is found to be superior to the "point contact" obtained by the traditional drop-casting method and facilitates electron transfer. Due to the intimate contact as well as the use of an ultralight GF current collector, the composite electrode delivers a gravimetric capacity of 642 mAh g(-1) and a volumetric capacity of 602 mAh cm(-3) with respect to the whole electrode mass and volume (including the active materials and the GF current collector). When normalized based on the mass of the active material, the composite electrode delivers a high specific capacity of up to 1687 mAh g(-1), which is superior to that of most graphene-based electrodes. Also, after ∼90 s charging, the anode delivers a capacity of about 100 mAh g(-1) (with respect to the total mass of the electrode), indicating its potential use in high-rate lithium-ion batteries.

  7. Rationally Designed Graphene-Nanotube 3D Architectures with a Seamless Nodal Junction for Efficient Energy Conversion and Storage

    DTIC Science & Technology

    2015-09-04

    Hao Chen,2 Jia Qu,2 Zhong Lin Wang,3,6* Liming Dai1,2* One-dimensional (1D) carbon nanotubes (CNTs) and 2D single-atomic layer graphene have superior...sources. INTRODUCTION Carbon nanomaterials, including one-dimensional (1D) carbon nano- tubes (CNTs) and 2D single-atomic layer graphene, have been...demon- strated to show superior thermal, electrical, and mechanical properties. Because of the presence of strong covalent bonding in the carbon plane

  8. A 3D Nanostructure Based on Transition-Metal Phosphide Decorated Heteroatom-Doped Mesoporous Nanospheres Interconnected with Graphene: Synthesis and Applications.

    PubMed

    Qiu, Shuilai; Xing, Weiyi; Mu, Xiaowei; Feng, Xiaming; Ma, Chao; Yuen, Richard K K; Hu, Yuan

    2016-11-30

    A novel three-dimensional nanostructure based on cobalt phosphide nanoparticles (Co2P NPs) and heteroatom-doped mesoporous carbon spheres interconnected with graphene (3D PZM@Co2P@RGO) was facilely synthesized for the first time, and it was used for enhancing the flame retardancy and toxicity suppression of epoxy resins (EP) via a synergistic effect. Herein, the cross-linked polyphosphazene hollow spheres (PZM) were used as templates for the fabrication of 3D architecture. The 3D architecture based on Co2P-decorated heteroatom-doped carbon sphere and reduced graphene oxide was prepared via a carbonization procedure followed by a hydrothermal self-assembly strategy. The as-prepared material exhibits excellent catalytic activity with regard to the combustion process. Notably, inclusion of incorporating PZM@Co2P@RGO resulted in a dramatic reduction of the fire hazards of EP, such as a 47.9% maximum decrease in peak heat release rate and a 29.2% maximum decrease in total heat release, lower toxic CO yield, and formation of high-graphitized protective char layer. In addition, the mechanism for flame retardancy and toxicity suppression was proposed. It is reasonable to know that the improved flame-retardant performance for EP nanocomposites is attributed to tripartite cooperative effect from respective components (Co2P NPs and RGO) plus the heteroatom-doped carbon spheres.

  9. Ultralight Graphene Foam/Conductive Polymer Composites for Exceptional Electromagnetic Interference Shielding.

    PubMed

    Wu, Ying; Wang, Zhenyu; Liu, Xu; Shen, Xi; Zheng, Qingbin; Xue, Quan; Kim, Jang-Kyo

    2017-03-15

    Ultralight, high-performance electromagnetic interference (EMI) shielding graphene foam (GF)/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) composites are developed by drop coating of PEDOT:PSS on cellular-structured, freestanding GFs. To enhance the wettability and the interfacial bonds with PEDOT:PSS, GFs are functionalized with 4-dodecylbenzenesulfonic acid. The GF/PEDOT:PSS composites possess an ultralow density of 18.2 × 10(-3) g/cm(3) and a high porosity of 98.8%, as well as an enhanced electrical conductivity by almost 4 folds from 11.8 to 43.2 S/cm after the incorporation of the conductive PEDOT:PSS. Benefiting from the excellent electrical conductivity, ultralight porous structure, and effective charge delocalization, the composites deliver remarkable EMI shielding performance with a shielding effectiveness (SE) of 91.9 dB and a specific SE (SSE) of 3124 dB·cm(3)/g, both of which are the highest among those reported in the literature for carbon-based polymer composites. The excellent electrical conductivities of composites arising from both the GFs with three-dimensionally interconnected conductive networks and the conductive polymer coating, as well as the left-handed composites with absolute permittivity and/or permeability larger than one give rise to significant microwave attenuation by absorption.

  10. Graphene Porous Foam Loaded with Molybdenum Carbide Nanoparticulate Electrocatalyst for Effective Hydrogen Generation.

    PubMed

    Wang, Jie; Xia, Han; Peng, Zhen; Lv, Cuncai; Jin, Lihuang; Zhao, Yaoxing; Huang, Zhipeng; Zhang, Chi

    2016-04-21

    A facile method is developed for the synthesis of graphene porous foam (Gr PF) loaded with dispersed molybdenum carbide (Mo2 C) nanoparticles; the material exhibits effective catalytic activity in the hydrogen evolution reaction (HER). Mo2 C/Gr PF is synthesized by the carbonization of glucose and the carbothermal reduction of hexaammonium molybdate in a confined space defined by the intervals between sodium chloride nanoparticles. The synthesis in the confined space results in thin Gr PF (≈8 nm) loaded with aggregation-free small Mo2 C nanoparticles [(13±2) nm]. The overpotential required for a current density of 20 mA cm(-2) in the electrochemical hydrogen generation is as small as 199 mV in acidic solution and 380 mV in basic solution. The performance is superior to that of a Mo2 C/C composite and compares favorably to those reported for Mo2 C nanostructures. The Mo2 C/Gr PF affords stable water electrolysis in both acidic and basic solution and exhibits nearly 100 % faradaic efficiency. The prominent performance, long-term stability, and high faradic efficiency make Mo2 C/Gr PF a promising HER catalyst for practical hydrogen generation from water electrolysis.

  11. Synthesis of functionalized 3D porous graphene using both ionic liquid and SiO2 spheres as "spacers" for high-performance application in supercapacitors.

    PubMed

    Li, Tingting; Li, Na; Liu, Jiawei; Cai, Kai; Foda, Mohamed F; Lei, Xiaomin; Han, Heyou

    2015-01-14

    In this work, a high-capacity supercapacitor material based on functionalized three-dimensional (3D) porous graphene was fabricated by low temperature hydrothermal treatment of graphene oxide (GO) using both ionic liquid (IL) and SiO2 spheres as "spacers". In the synthesis, the introduction of dual "spacers" effectively enlarged the interspace between graphene sheets and suppressed their re-stacking. In addition, the IL also acted as a structure-directing agent playing a crucial role in inducing the formation of unique 3D architectures. Consequently, fast electron/ion transport channels were successfully constructed and numerous oxygen-containing groups on graphene sheets were effectively reserved, which had unique advantages in decreasing ion diffusion resistance and providing additional pseudocapacitance. As expected, the obtained material exhibited superior specific capacitance and rate capability compared to single "spacer" designed electrodes and simultaneously maintained excellent cycling stability. In particular, there was nearly no loss of its initial capacitance after 3000 cycles. In addition, we further assembled a symmetric two-electrode device using the material, which showed outstanding flexibility and low equivalent series resistance (ESR). More importantly, it was capable of yielding a maximum power density of about 13.3 kW kg(-1) with an energy density of about 7.0 W h kg(-1) at a voltage of 1.0 V in 1 M H2SO4 electrolyte. All these impressive results demonstrate that the material obtained by this approach is greatly promising for application in high-performance supercapacitors.

  12. Nanohole-Structured and Palladium-Embedded 3D Porous Graphene for Ultrahigh Hydrogen Storage and CO Oxidation Multifunctionalities.

    PubMed

    Kumar, Rajesh; Oh, Jung-Hwan; Kim, Hyun-Jun; Jung, Jung-Hwan; Jung, Chan-Ho; Hong, Won G; Kim, Hae-Jin; Park, Jeong-Young; Oh, Il-Kwon

    2015-07-28

    Atomic-scale defects on carbon nanostructures have been considered as detrimental factors and critical problems to be eliminated in order to fully utilize their intrinsic material properties such as ultrahigh mechanical stiffness and electrical conductivity. However, defects that can be intentionally controlled through chemical and physical treatments are reasonably expected to bring benefits in various practical engineering applications such as desalination thin membranes, photochemical catalysts, and energy storage materials. Herein, we report a defect-engineered self-assembly procedure to produce a three-dimensionally nanohole-structured and palladium-embedded porous graphene hetero-nanostructure having ultrahigh hydrogen storage and CO oxidation multifunctionalities. Under multistep microwave reactions, agglomerated palladium nanoparticles having diameters of ∼10 nm produce physical nanoholes in the basal-plane structure of graphene sheets, while much smaller palladium nanoparticles are readily impregnated inside graphene layers and bonded on graphene surfaces. The present results show that the defect-engineered hetero-nanostructure has a ∼5.4 wt % hydrogen storage capacity under 7.5 MPa and CO oxidation catalytic activity at 190 °C. The defect-laden graphene can be highly functionalized for multipurpose applications such as molecule absorption, electrochemical energy storage, and catalytic activity, resulting in a pathway to nanoengineering based on underlying atomic scale and physical defects.

  13. Nickel–cobalt layered double hydroxide ultrathin nanoflakes decorated on graphene sheets with a 3D nanonetwork structure as supercapacitive materials

    SciTech Connect

    Yan, Tao; Li, Ruiyi; Li, Zaijun

    2014-03-01

    Graphical abstract: The microwave heating reflux approach was developed for the fabrication of nickel–cobalt layered double hydroxide ultrathin nanoflakes decorated on graphene sheets, in which ammonia and ethanol were used as the precipitator and medium for the synthesis. The obtained composite shows a 3D flowerclusters morphology with nanonetwork structure and largely enhanced supercapacitive performance. - Highlights: • The paper reported the microwave synthesis of nickel–cobalt layered double hydroxide/graphene composite. • The novel synthesis method is rapid, green, efficient and can be well used to the mass production. • The as-synthesized composite offers a 3D flowerclusters morphology with nanonetwork structure. • The composite offers excellent supercapacitive performance. • This study provides a promising route to design and synthesis of advanced graphene-based materials with the superiorities of time-saving and cost-effective characteristics. - Abstract: The study reported a novel microwave heating reflux method for the fabrication of nickel–cobalt layered double hydroxide ultrathin nanoflakes decorated on graphene sheets (GS/NiCo-LDH). Ammonia and ethanol were employed as precipitant and reaction medium for the synthesis, respectively. The resulting GS/NiCo-LDH offers a 3D flowerclusters morphology with nanonetwork structure. Due to the greatly enhanced rate of electron transfer and mass transport, the GS/NiCo-LDH electrode exhibits excellent supercapacitive performances. The maximum specific capacitance was found to be 1980.7 F g{sup −1} at the current density of 1 A g{sup −1}. The specific capacitance can remain 1274.7 F g{sup −1} at the current density of 15 A g{sup −1} and it has an increase of about 2.9% after 1500 cycles. Moreover, the study also provides a promising approach for the design and synthesis of metallic double hydroxides/graphene hybrid materials with time-saving and cost-effective characteristics, which can be

  14. Reduced graphene oxide/carbon double-coated 3-D porous ZnO aggregates as high-performance Li-ion anode materials.

    PubMed

    Wi, Sungun; Woo, Hyungsub; Lee, Sangheon; Kang, Joonhyeon; Kim, Jaewon; An, Subin; Kim, Chohui; Nam, Seunghoon; Kim, Chunjoong; Park, Byungwoo

    2015-01-01

    The reduced graphene oxide (RGO)/carbon double-coated 3-D porous ZnO aggregates (RGO/C/ZnO) have been successfully synthesized as anode materials for Li-ion batteries with excellent cyclability and rate capability. The mesoporous ZnO aggregates prepared by a simple solvothermal method are sequentially modified through distinct carbon-based double coating. These novel architectures take unique advantages of mesopores acting as space to accommodate volume expansion during cycling, while the conformal carbon layer on each nanoparticle buffering volume changes, and conductive RGO sheets connect the aggregates to each other. Consequently, the RGO/C/ZnO exhibits superior electrochemical performance, including remarkably prolonged cycle life and excellent rate capability. Such improved performance of RGO/C/ZnO may be attributed to synergistic effects of both the 3-D porous nanostructures and RGO/C double coating.

  15. Reduced graphene oxide/carbon double-coated 3-D porous ZnO aggregates as high-performance Li-ion anode materials

    NASA Astrophysics Data System (ADS)

    Wi, Sungun; Woo, Hyungsub; Lee, Sangheon; Kang, Joonhyeon; Kim, Jaewon; An, Subin; Kim, Chohui; Nam, Seunghoon; Kim, Chunjoong; Park, Byungwoo

    2015-05-01

    The reduced graphene oxide (RGO)/carbon double-coated 3-D porous ZnO aggregates (RGO/C/ZnO) have been successfully synthesized as anode materials for Li-ion batteries with excellent cyclability and rate capability. The mesoporous ZnO aggregates prepared by a simple solvothermal method are sequentially modified through distinct carbon-based double coating. These novel architectures take unique advantages of mesopores acting as space to accommodate volume expansion during cycling, while the conformal carbon layer on each nanoparticle buffering volume changes, and conductive RGO sheets connect the aggregates to each other. Consequently, the RGO/C/ZnO exhibits superior electrochemical performance, including remarkably prolonged cycle life and excellent rate capability. Such improved performance of RGO/C/ZnO may be attributed to synergistic effects of both the 3-D porous nanostructures and RGO/C double coating.

  16. Li2S@C composite incorporated into 3D reduced graphene oxide as a cathode material for lithium-sulfur batteries

    NASA Astrophysics Data System (ADS)

    Wang, D. H.; Xie, D.; Yang, T.; Zhong, Y.; Wang, X. L.; Xia, X. H.; Gu, C. D.; Tu, J. P.

    2016-05-01

    Surface conductive engineering on Li2S is critical for construction of advanced cathodes of lithium-sulfur batteries. Herein, we construct a high-performance Li2S-based composite cathode with the help of three-dimensional reduced graphene oxide (3D-rGO) network and outer carbon coating. Typically, the Li2S@C particles are uniformly embedded into 3D-rGO to form a binder-free 3D-rGO-Li2S@C cathode by the combination of a liquid solution-evaporation coating and PVP (Polyvinyl Pyrrolidone) carbonization. The 3D-rGO-Li2S@C cathode exhibits a high initial discharge capacity of 856 mAh g-1 at 0.1C, superior cycling stability with a capacity of 388.4 mAh g-1 after 200 cycles at 1C, corresponding to a low capacity fading rate. It is demonstrated that the outer conductive coating is effective and necessary for electrochemical enhancement of Li2S cathodes by improving electrical conductivity and prohibiting polysulfide from shuttling during cycling.

  17. Synthesis and Application of Novel 3D Magnetic Chlorogenic Acid Imprinted Polymers Based on a Graphene-Carbon Nanotube Composite.

    PubMed

    Yan, Liang; Yin, Yuli; Lv, Piaopiao; Zhang, Zhaohui; Wang, Jing; Long, Fang

    2016-04-20

    A novel three-dimensional (3D) magnetic chlorogenic acid (CGA) imprinted polymer (MMIP) was prepared with novel carbon hybrid nanocomposite as the carrier, chlorogenic acid as the template molecule, and methacrylic acid as the functional monomer. The 3D MMIPs were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, vibrating sample magnetometer, and UV spectrometry in detail. The results showed that the imprinted layer was attached successfully on the surface of a 3D magnetic carbon hybrid nanocomposite. The adsorption performance of the 3D MMIPs was investigated, and the results showed that the 3D MMIPs exhibited high adsorption capacity and fast adsorption rate toward CGA with a maximum adsorption capacity of 10.88 mg g(-1). The extraction conditions involving washing solvent, the pH of eluent solvent, elution volume, and desorption time were also investigated in detail. Combined with high-performance liquid chromatography, the 3D MMIPs have been applied to successfully extract CGA from Eucommia leaf extract samples.

  18. Bio-Conjugated CNT-Bridged 3D Porous Graphene Oxide Membrane for Highly Efficient Disinfection of Pathogenic Bacteria and Removal of Toxic Metals from Water.

    PubMed

    Nellore, Bhanu Priya Viraka; Kanchanapally, Rajashekhar; Pedraza, Francisco; Sinha, Sudarson Sekhar; Pramanik, Avijit; Hamme, Ashton T; Arslan, Zikri; Sardar, Dhiraj; Ray, Paresh Chandra

    2015-09-02

    More than a billion people lack access to safe drinking water that is free from pathogenic bacteria and toxic metals. The World Health Organization estimates several million people, mostly children, die every year due to the lack of good quality water. Driven by this need, we report the development of PGLa antimicrobial peptide and glutathione conjugated carbon nanotube (CNT) bridged three-dimensional (3D) porous graphene oxide membrane, which can be used for highly efficient disinfection of Escherichia coli O157:H7 bacteria and removal of As(III), As(V), and Pb(II) from water. Reported results demonstrate that versatile membrane has the capability to capture and completely disinfect pathogenic pathogenic E. coli O157:H7 bacteria from water. Experimentally observed disinfection data indicate that the PGLa attached membrane can dramatically enhance the possibility of destroying pathogenic E. coli bacteria via synergistic mechanism. Reported results show that glutathione attached CNT-bridged 3D graphene oxide membrane can be used to remove As(III), As(V), and Pb(II) from water sample at 10 ppm level. Our data demonstrated that PGLa and glutathione attached membrane has the capability for high efficient removal of E. coli O157:H7 bacteria, As(III), As(V), and Pb(II) simultaneously from Mississippi River water.

  19. Self-Assembled 3D Graphene-Based Aerogel with Co3 O4 Nanoparticles as High-Performance Asymmetric Supercapacitor Electrode.

    PubMed

    Xie, Lijing; Su, Fangyuan; Xie, Longfei; Li, Xiaoming; Liu, Zhuo; Kong, Qingqiang; Guo, Xiaohui; Zhang, Yaoyao; Wan, Liu; Li, Kaixi; Lv, Chunxiang; Chen, Chengmeng

    2015-09-07

    Using graphene oxide and a cobalt salt as precursor, a three-dimensional graphene aerogel with embedded Co3 O4 nanoparticles (3D Co3 O4 -RGO aerogel) is prepared by means of a solvothermal approach and subsequent freeze-drying and thermal reduction. The obtained 3D Co3 O4 -RGO aerogel has a high specific capacitance of 660 F g(-1) at 0.5 A g(-1) and a high rate capability of 65.1 % retention at 50 A g(-1) in a three-electrode system. Furthermore, the material is used as cathode to fabricate an asymmetric supercapacitor utilizing a hierarchical porous carbon (HPC) as anode and 6 M KOH aqueous solution as electrolyte. In a voltage range of 0.0 to 1.5 V, the device exhibits a high energy density of 40.65 Wh kg(-1) and a power density of 340 W kg(-1) and shows a high cycling stability (92.92 % capacitance retention after 2000 cycles). After charging for only 30 s, three CR2032 coin-type asymmetric supercapacitors in series can drive a light-emitting-diode (LED) bulb brightly for 30 min, which remains effective even after 1 h.

  20. Hydrothermal synthesis of manganese phosphate/graphene foam composite for electrochemical supercapacitor applications.

    PubMed

    Mirghni, Abdulmajid Abdallah; Madito, Moshawe Jack; Masikhwa, Tshifhiwa Moureen; Oyedotun, Kabir O; Bello, Abdulhakeem; Manyala, Ncholu

    2017-05-15

    Manganese phosphate (Mn3(PO4)2 hexagonal micro-rods and (Mn3(PO4)2 with different graphene foam (GF) mass loading up to 150mg were prepared by facile hydrothermal method. The characterization of the as-prepared samples proved the successful synthesis of Mn3(PO4)2 hexagonal micro-rods and Mn3(PO4)2/GF composites. It was observed that the specific capacitance of Mn3(PO4)2/GF composites with different GF mass loading increases with mass loading up to 100mg, and then decreases with increasing mass loading up to 150mg. The specific capacitance of Mn3(PO4)2/100mg GF electrode was calculated to be 270Fg(-1) as compared to 41Fg(-1) of the pristine sample at a current density of 0.5Ag(-1) in a three-electrode cell configuration using 6M KOH. Furthermore, the electrochemical performance of the Mn3(PO4)2/100mg GF electrode was evaluated in a two-electrode asymmetric cell device where Mn3(PO4)2/100mg GF electrode was used as a positive electrode and activated carbon (AC) from coconut shell as a negative electrode. AC//Mn3(PO4)2/100mg GF asymmetric cell device was tested within the potential window of 0.0-1.4V, and showed excellent cycling stability with 96% capacitance retention over 10,000 galvanostatic charge-discharge cycles at a current density of 2Ag(-1).

  1. 3D nanospherical CdxZn1-xS/reduced graphene oxide composites with superior photocatalytic activity and photocorrosion resistance

    NASA Astrophysics Data System (ADS)

    Huang, Meina; Yu, Jianhua; Deng, Changshun; Huang, Yingheng; Fan, Minguang; Li, Bin; Tong, Zhangfa; Zhang, Feiyue; Dong, Lihui

    2016-03-01

    Herein, a series of CdxZn1-xS and sulfide/graphene photocatalysts with 3D nanospherical framework have been successfully fabricated by one-pot solvothermal method for the first time. The morphology and structure of samples were confirmed by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray (EDX) spectrometry, N2 adsorption, Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS). The as-prepared samples exhibit excellent photocatalytic activities and photocorrosion resistance in the degradation of dyes under visible light. The Cd0.5Zn0.5S/rGO sample shows the most efficient in the photodegradation of methyl orange (MO). It takes about 30 min for degradation completely. The enhanced photocatalytic activity is mainly attributed to the slow photon enhancement of the 3D structure, and the heterojunction between the 3D nanospherical Cd0.5Zn0.5S solid solutions and a high quality 2D rGO support, which can greatly promote the separation of light-induced electrons and holes. Moreover, the large SBET and extended light absorption range also play an important role for improving the photocatalytic activity. The high photocatalytic stability is due to the successful inhibition of the photocorrosion of Cd0.5Zn0.5S/rGO by forming heterojunction between CdS and ZnS, and transferring the photogenerated electrons of Cd0.5Zn0.5S to rGO. The present work can provide rational design of graphene-based photocatalysts with large contact interface and strong interaction between the composites for other application.

  2. 3D dual-confined sulfur encapsulated in porous carbon nanosheets and wrapped with graphene aerogels as a cathode for advanced lithium sulfur batteries

    NASA Astrophysics Data System (ADS)

    Hou, Yang; Li, Jianyang; Gao, Xianfeng; Wen, Zhenhai; Yuan, Chris; Chen, Junhong

    2016-04-01

    Although lithium-sulfur (Li-S) batteries have attracted much attention due to their high theoretical specific energy and low cost, their practical applications have been severely hindered by poor cycle life, inadequate sulfur utilization, and the insulating nature of sulfur. Here, we report a rationally designed Li-S cathode with a dual-confined configuration formed by confining sulfur in 2D carbon nanosheets with an abundant porous structure followed by 3D graphene aerogel wrapping. The porous carbon nanosheets act as the sulfur host and suppress the diffusion of polysulfide, while the graphene conductive networks anchor the sulfur-adsorbed carbon nanosheets, providing pathways for rapid electron/ion transport and preventing polysulfide dissolution. As a result, the hybrid electrode exhibits superior electrochemical performance, including a large reversible capacity of 1328 mA h g-1 in the first cycle, excellent cycling stability (maintaining a reversible capacity of 647 mA h g-1 at 0.2 C after 300 cycles) with nearly 100% Coulombic efficiency, and a high rate capability of 512 mA h g-1 at 8 C for 30 cycles, which is among the best reported rate capabilities.Although lithium-sulfur (Li-S) batteries have attracted much attention due to their high theoretical specific energy and low cost, their practical applications have been severely hindered by poor cycle life, inadequate sulfur utilization, and the insulating nature of sulfur. Here, we report a rationally designed Li-S cathode with a dual-confined configuration formed by confining sulfur in 2D carbon nanosheets with an abundant porous structure followed by 3D graphene aerogel wrapping. The porous carbon nanosheets act as the sulfur host and suppress the diffusion of polysulfide, while the graphene conductive networks anchor the sulfur-adsorbed carbon nanosheets, providing pathways for rapid electron/ion transport and preventing polysulfide dissolution. As a result, the hybrid electrode exhibits superior

  3. Unraveling the 3D Atomic Structure of a Suspended Graphene/hBN van der Waals Heterostructure.

    PubMed

    Argentero, Giacomo; Mittelberger, Andreas; Reza Ahmadpour Monazam, Mohammad; Cao, Yang; Pennycook, Timothy J; Mangler, Clemens; Kramberger, Christian; Kotakoski, Jani; Geim, A K; Meyer, Jannik C

    2017-03-08

    In this work we demonstrate that a free-standing van der Waals heterostructure, usually regarded as a flat object, can exhibit an intrinsic buckled atomic structure resulting from the interaction between two layers with a small lattice mismatch. We studied a freely suspended membrane of well-aligned graphene on a hexagonal boron nitride (hBN) monolayer by transmission electron microscopy (TEM) and scanning TEM (STEM). We developed a detection method in the STEM that is capable of recording the direction of the scattered electron beam and that is extremely sensitive to the local stacking of atoms. A comparison between experimental data and simulated models shows that the heterostructure effectively bends in the out-of-plane direction, producing an undulated structure having a periodicity that matches the moiré wavelength. We attribute this rippling to the interlayer interaction and also show how this affects the intralayer strain in each layer.

  4. Unraveling the 3D Atomic Structure of a Suspended Graphene/hBN van der Waals Heterostructure

    NASA Astrophysics Data System (ADS)

    Argentero, Giacomo; Mittelberger, Andreas; Reza Ahmadpour Monazam, Mohammad; Cao, Yang; Pennycook, Timothy J.; Mangler, Clemens; Kramberger, Christian; Kotakoski, Jani; Geim, A. K.; Meyer, Jannik C.

    2017-03-01

    In this work we demonstrate that a free-standing van der Waals heterostructure, usually regarded as a flat object, can exhibit an intrinsic buckled atomic structure resulting from the interaction between two layers with a small lattice mismatch. We studied a freely suspended membrane of well aligned graphene on a hexagonal boron nitride (hBN) monolayer by transmission electron microscopy (TEM) and scanning TEM (STEM). We developed a detection method in the STEM that is capable of recording the direction of the scattered electron beam and that is extremely sensitive to the local stacking of atoms. Comparison between experimental data and simulated models shows that the heterostructure effectively bends in the out-of-plane direction, producing an undulated structure having a periodicity that matches the moir\\'e wavelength. We attribute this rippling to the interlayer interaction and also show how this affects the intralayer strain in each layer.

  5. Unraveling the 3D Atomic Structure of a Suspended Graphene/hBN van der Waals Heterostructure

    PubMed Central

    2017-01-01

    In this work we demonstrate that a free-standing van der Waals heterostructure, usually regarded as a flat object, can exhibit an intrinsic buckled atomic structure resulting from the interaction between two layers with a small lattice mismatch. We studied a freely suspended membrane of well-aligned graphene on a hexagonal boron nitride (hBN) monolayer by transmission electron microscopy (TEM) and scanning TEM (STEM). We developed a detection method in the STEM that is capable of recording the direction of the scattered electron beam and that is extremely sensitive to the local stacking of atoms. A comparison between experimental data and simulated models shows that the heterostructure effectively bends in the out-of-plane direction, producing an undulated structure having a periodicity that matches the moiré wavelength. We attribute this rippling to the interlayer interaction and also show how this affects the intralayer strain in each layer. PMID:28140602

  6. How We 3D-Print Aerogel

    SciTech Connect

    2015-04-23

    A new type of graphene aerogel will make for better energy storage, sensors, nanoelectronics, catalysis and separations. Lawrence Livermore National Laboratory researchers have made graphene aerogel microlattices with an engineered architecture via a 3D printing technique known as direct ink writing. The research appears in the April 22 edition of the journal, Nature Communications. The 3D printed graphene aerogels have high surface area, excellent electrical conductivity, are lightweight, have mechanical stiffness and exhibit supercompressibility (up to 90 percent compressive strain). In addition, the 3D printed graphene aerogel microlattices show an order of magnitude improvement over bulk graphene materials and much better mass transport.

  7. 3D dual-confined sulfur encapsulated in porous carbon nanosheets and wrapped with graphene aerogels as a cathode for advanced lithium sulfur batteries.

    PubMed

    Hou, Yang; Li, Jianyang; Gao, Xianfeng; Wen, Zhenhai; Yuan, Chris; Chen, Junhong

    2016-04-21

    Although lithium-sulfur (Li-S) batteries have attracted much attention due to their high theoretical specific energy and low cost, their practical applications have been severely hindered by poor cycle life, inadequate sulfur utilization, and the insulating nature of sulfur. Here, we report a rationally designed Li-S cathode with a dual-confined configuration formed by confining sulfur in 2D carbon nanosheets with an abundant porous structure followed by 3D graphene aerogel wrapping. The porous carbon nanosheets act as the sulfur host and suppress the diffusion of polysulfide, while the graphene conductive networks anchor the sulfur-adsorbed carbon nanosheets, providing pathways for rapid electron/ion transport and preventing polysulfide dissolution. As a result, the hybrid electrode exhibits superior electrochemical performance, including a large reversible capacity of 1328 mA h g(-1) in the first cycle, excellent cycling stability (maintaining a reversible capacity of 647 mA h g(-1) at 0.2 C after 300 cycles) with nearly 100% Coulombic efficiency, and a high rate capability of 512 mA h g(-1) at 8 C for 30 cycles, which is among the best reported rate capabilities.

  8. Integrating 3D Flower-Like Hierarchical Cu2NiSnS4 with Reduced Graphene Oxide as Advanced Anode Materials for Na-Ion Batteries.

    PubMed

    Yuan, Shuang; Wang, Sai; Li, Lin; Zhu, Yun-hai; Zhang, Xin-bo; Yan, Jun-min

    2016-04-13

    Development of an anode material with high performance and low cost is crucial for implementation of next-generation Na-ion batteries (NIBs) electrode, which is proposed to meet the challenges of large scale renewable energy storage. Metal chalcogenides are considered as promising anode materials for NIBs due to their high theoretical capacity, low cost, and abundant sources. Unfortunately, their practical application in NIBs is still hindered because of low conductivity and morphological collapse caused by their volume expansion and shrinkage during Na(+) intercalation/deintercalation. To solve the daunting challenges, herein, we fabricated novel three-dimensional (3D) Cu2NiSnS4 nanoflowers (CNTSNs) as a proof-of-concept experiment using a facile and low-cost method. Furthermore, homogeneous integration with reduced graphene oxide nanosheets (RGNs) endows intrinsically insulated CNTSNs with superior electrochemical performances, including high specific capacity (up to 837 mAh g(-1)), good rate capability, and long cycling stability, which could be attributed to the unique 3D hierarchical structure providing fast ion diffusion pathway and high contact area at the electrode/electrolyte interface.

  9. A 3D graphene oxide microchip and a Au-enwrapped silica nanocomposite-based supersandwich cytosensor toward capture and analysis of circulating tumor cells

    NASA Astrophysics Data System (ADS)

    Li, Na; Xiao, Tingyu; Zhang, Zhengtao; He, Rongxiang; Wen, Dan; Cao, Yiping; Zhang, Weiying; Chen, Yong

    2015-10-01

    Determination of the presence and number of circulating tumor cells (CTCs) in peripheral blood can provide clinically important data for prognosis and therapeutic response patterns. In this study, a versatile supersandwich cytosensor was successfully developed for the highly sensitive and selective analysis of CTCs using Au-enwrapped silica nanocomposites (Si/AuNPs) and three-dimensional (3D) microchips. First, 3D microchips were fabricated by a photolithography method. Then, the prepared substrate was applied to bind graphene oxide, streptavidin and biotinylated epithelial-cell adhesion-molecule antibody, resulting in high stability, bioactivity, and capability for CTCs capture. Furthermore, horseradish peroxidase and anti-CA153 were co-linked to the Si/AuNPs for signal amplification. The performance of the cytosensor was evaluated with MCF7 breast cancer cells. Under optimal conditions, the proposed supersandwich cytosensor showed high sensitivity with a wide range of 101 to 107 cells per mL and a detection limit of 10 cells per mL. More importantly, it could effectively distinguish CTCs from normal cells, which indicated the promising applications of our method for the clinical diagnosis and therapeutic monitoring of cancers.

  10. Fabrication of 3D honeycomb-like porous polyurethane-functionalized reduced graphene oxide for detection of dopamine.

    PubMed

    Vilian, A T Ezhil; An, Suyeong; Choe, Sang Rak; Kwak, Cheol Hwan; Huh, Yun Suk; Lee, Jonghwi; Han, Young-Kyu

    2016-12-15

    A three dimensional reduced graphene oxide/polyurethane (RGO-PU) porous material with connected pores was prepared by physical adsorption of RGO onto the surface of porous PU. The porous PU was prepared by directional melt crystallization of a solvent, which produced high pores with controlled orientation. The prepared RGO-PU was characterized by scanning electron microscopy, spectroscopy and electro-chemical methods. The RGO-PU porous material revealed better electrochemical performance, which might be attributed to the robust structure, superior conductivity, large surface area, and good flexibility. Differential pulse voltammetry (DPV) analysis of DA using the RGO-PU exhibited a linear response range over a wide DA concentration of 100-1150pM, with the detection limit of 1pM. This sensor exhibited outstanding anti-interference ability towards co-existing molecules with good stability, sensitivity, and reproducibility. Furthermore, the fabricated sensor was successfully applied for the quantitative analysis of DA in human serum and urine samples with acceptable recovery, which indicates its feasibility for practical application.

  11. Facile construction of 3D graphene/MoS2 composites as advanced electrode materials for supercapacitors

    NASA Astrophysics Data System (ADS)

    Sun, Tianhua; Li, Zhangpeng; Liu, Xiaohong; Ma, Limin; Wang, Jinqing; Yang, Shengrong

    2016-11-01

    Flower-like molybdenum disulfide (MoS2) microstructures are synthesized based on three-dimensional graphene (3DG) skeleton via a simple and facile one-step hydrothermal method, aiming at constructing series of novel composite electrode materials of 3DG/MoS2 with high electrochemical performances for supercapacitors. The electrochemical properties of the samples are evaluated by cyclic voltammetry and galvanostatic charge/discharge tests. Specifically, the optimal 3DG/MoS2 composite exhibits remarkable performances with a high specific capacitance of 410 F g-1 at a current density of 1 A g-1 and an excellent cycling stability with ca. 80.3% capacitance retention after 10,000 continuous charge-discharge cycles at a high current density of 2 A g-1, making it adaptive for high-performance supercapacitors. The enhanced electrochemical performances can be ascribed to the combination of 3DG and flower-like MoS2, which provides excellent charge transfer network and electrolyte diffusion channels while effectively prevents the collapse, aggregation and morphology change of active materials during charge-discharge process. The results demonstrate that 3DG/MoS2 composite is one of the attractive electrode materials for supercapacitors.

  12. Porous three-dimensional graphene foam/Prussian blue composite for efficient removal of radioactive 137Cs

    PubMed Central

    Jang, Sung-Chan; Haldorai, Yuvaraj; Lee, Go-Woon; Hwang, Seung-Kyu; Han, Young-Kyu; Roh, Changhyun; Huh, Yun Suk

    2015-01-01

    In this study, a simple one-step hydrothermal reaction is developed to prepare composite based on Prussian blue (PB)/reduced graphene oxide foam (RGOF) for efficient removal of radioactive cesium (137Cs) from contaminated water. Scanning electron microscopy and transmission electron microscopy show that cubic PB nanoparticles are decorated on the RGO surface. Owing to the combined benefits of RGOF and PB, the composite shows excellent removal efficiency (99.5%) of 137Cs from the contaminated water. The maximum adsorption capacity is calculated to be 18.67 mg/g. An adsorption isotherm fit-well the Langmuir model with a linear regression correlation value of 0.97. This type of composite is believed to hold great promise for the clean-up of 137Cs from contaminated water around nuclear plants and/or after nuclear accidents. PMID:26670798

  13. Porous three-dimensional graphene foam/Prussian blue composite for efficient removal of radioactive (137)Cs.

    PubMed

    Jang, Sung-Chan; Haldorai, Yuvaraj; Lee, Go-Woon; Hwang, Seung-Kyu; Han, Young-Kyu; Roh, Changhyun; Huh, Yun Suk

    2015-12-16

    In this study, a simple one-step hydrothermal reaction is developed to prepare composite based on Prussian blue (PB)/reduced graphene oxide foam (RGOF) for efficient removal of radioactive cesium ((137)Cs) from contaminated water. Scanning electron microscopy and transmission electron microscopy show that cubic PB nanoparticles are decorated on the RGO surface. Owing to the combined benefits of RGOF and PB, the composite shows excellent removal efficiency (99.5%) of (137)Cs from the contaminated water. The maximum adsorption capacity is calculated to be 18.67 mg/g. An adsorption isotherm fit-well the Langmuir model with a linear regression correlation value of 0.97. This type of composite is believed to hold great promise for the clean-up of (137)Cs from contaminated water around nuclear plants and/or after nuclear accidents.

  14. Synergistic effects from graphene and carbon nanotubes endow ordered hierarchical structure foams with a combination of compressibility, super-elasticity and stability and potential application as pressure sensors

    NASA Astrophysics Data System (ADS)

    Kuang, Jun; Dai, Zhaohe; Liu, Luqi; Yang, Zhou; Jin, Ming; Zhang, Zhong

    2015-05-01

    Nanostructured carbon material based three-dimensional porous architectures have been increasingly developed for various applications, e.g. sensors, elastomer conductors, and energy storage devices. Maintaining architectures with good mechanical performance, including elasticity, load-bearing capacity, fatigue resistance and mechanical stability, is prerequisite for realizing these functions. Though graphene and CNT offer opportunities as nanoscale building blocks, it still remains a great challenge to achieve good mechanical performance in their microarchitectures because of the need to precisely control the structure at different scales. Herein, we fabricate a hierarchical honeycomb-like structured hybrid foam based on both graphene and CNT. The resulting materials possess excellent properties of combined high specific strength, elasticity and mechanical stability, which cannot be achieved in neat CNT and graphene foams. The improved mechanical properties are attributed to the synergistic-effect-induced highly organized, multi-scaled hierarchical architectures. Moreover, with their excellent electrical conductivity, we demonstrated that the hybrid foams could be used as pressure sensors in the fields related to artificial skin.Nanostructured carbon material based three-dimensional porous architectures have been increasingly developed for various applications, e.g. sensors, elastomer conductors, and energy storage devices. Maintaining architectures with good mechanical performance, including elasticity, load-bearing capacity, fatigue resistance and mechanical stability, is prerequisite for realizing these functions. Though graphene and CNT offer opportunities as nanoscale building blocks, it still remains a great challenge to achieve good mechanical performance in their microarchitectures because of the need to precisely control the structure at different scales. Herein, we fabricate a hierarchical honeycomb-like structured hybrid foam based on both graphene and

  15. Facile synthesis of novel 3D nanoflower-like CuxO/multilayer graphene composites for room temperature NOx gas sensor application

    NASA Astrophysics Data System (ADS)

    Yang, Ying; Tian, Chungui; Wang, Jingchao; Sun, Li; Shi, Keying; Zhou, Wei; Fu, Honggang

    2014-06-01

    3D nanoflower-like CuxO/multilayer graphene composites (CuMGCs) have been successfully synthesized as a new type of room temperature NOx gas sensor. Firstly, the expanded graphite (EG) was activated by KOH and many moderate functional groups were generated; secondly, Cu(CH3COO)2 and CTAB underwent full infusion into the interlayers of activated EG (aEG) by means of a vacuum-assisted technique and then reacted with the functional groups of aEG accompanied by the exfoliation of aEG via reflux. Eventually, the 3D nanoflower consisting of 5-9 nm CuxO nanoparticles homogeneously grow in situ on aEG. The KOH activation of EG plays a key role in the uniform formation of CuMGCs. When being used as gas sensors for detection of NOx, the CuMGCs achieved a higher response at room temperature than that of the corresponding CuxO. In detail, the CuMGCs show a higher NOx gas sensing performance with low detection limit of 97 ppb, high gas response of 95.1% and short response time of 9.6 s to 97.0 ppm NOx at room temperature. Meanwhile, the CuMGC sensor presents a favorable linearity, good selectivity and stability. The enhancement of the sensing response is mainly attributed to the improved conductivity of the CuMGCs. A series of Mott-Schottky and EIS measurements demonstrated that the CuMGCs have much higher donor densities than CuxO and can easily capture and migrate electrons from the conduction band, resulting in the enhancement of electrical conductivity.3D nanoflower-like CuxO/multilayer graphene composites (CuMGCs) have been successfully synthesized as a new type of room temperature NOx gas sensor. Firstly, the expanded graphite (EG) was activated by KOH and many moderate functional groups were generated; secondly, Cu(CH3COO)2 and CTAB underwent full infusion into the interlayers of activated EG (aEG) by means of a vacuum-assisted technique and then reacted with the functional groups of aEG accompanied by the exfoliation of aEG via reflux. Eventually, the 3D nanoflower

  16. 3D macroporous electrode and high-performance in lithium-ion batteries using SnO2 coated on Cu foam.

    PubMed

    Um, Ji Hyun; Choi, Myounggeun; Park, Hyeji; Cho, Yong-Hun; Dunand, David C; Choe, Heeman; Sung, Yung-Eun

    2016-01-04

    A three-dimensional porous architecture makes an attractive electrode structure, as it has an intrinsic structural integrity and an ability to buffer stress in lithium-ion batteries caused by the large volume changes in high-capacity anode materials during cycling. Here we report the first demonstration of a SnO2-coated macroporous Cu foam anode by employing a facile and scalable combination of directional freeze-casting and sol-gel coating processes. The three-dimensional interconnected anode is composed of aligned microscale channels separated by SnO2-coated Cu walls and much finer micrometer pores, adding to surface area and providing space for volume expansion of SnO2 coating layer. With this anode, we achieve a high reversible capacity of 750 mAh g(-1) at current rate of 0.5 C after 50 cycles and an excellent rate capability of 590 mAh g(-1) at 2 C, which is close to the best performance of Sn-based nanoscale material so far.

  17. 3D macroporous electrode and high-performance in lithium-ion batteries using SnO2 coated on Cu foam

    PubMed Central

    Um, Ji Hyun; Choi, Myounggeun; Park, Hyeji; Cho, Yong-Hun; Dunand, David C.; Choe, Heeman; Sung, Yung-Eun

    2016-01-01

    A three-dimensional porous architecture makes an attractive electrode structure, as it has an intrinsic structural integrity and an ability to buffer stress in lithium-ion batteries caused by the large volume changes in high-capacity anode materials during cycling. Here we report the first demonstration of a SnO2-coated macroporous Cu foam anode by employing a facile and scalable combination of directional freeze-casting and sol-gel coating processes. The three-dimensional interconnected anode is composed of aligned microscale channels separated by SnO2-coated Cu walls and much finer micrometer pores, adding to surface area and providing space for volume expansion of SnO2 coating layer. With this anode, we achieve a high reversible capacity of 750 mAh g−1 at current rate of 0.5 C after 50 cycles and an excellent rate capability of 590 mAh g−1 at 2 C, which is close to the best performance of Sn-based nanoscale material so far. PMID:26725652

  18. 3D assembly based on 2D structure of Cellulose Nanofibril/Graphene Oxide Hybrid Aerogel for Adsorptive Removal of Antibiotics in Water

    PubMed Central

    Yao, Qiufang; Fan, Bitao; Xiong, Ye; Jin, Chunde; Sun, Qingfeng; Sheng, Chengmin

    2017-01-01

    Cellulose nanofibril/graphene oxide hybrid (CNF/GO) aerogel was fabricated via a one-step ultrasonication method for adsorptive removal of 21 kinds of antibiotics in water. The as-prepared CNF/GO aerogel possesses interconnected 3D network microstructure, in which GO nanosheets with 2D structure were intimately grown along CNF through hydrogen bonds. The aerogel exhibited superior adsorption capacity toward the antibiotics. The removal percentages (R%) of the antibiotics were more than 69% and the sequence of six categories antibiotics according to the adsorption efficiency was as follows: Tetracyclines > Quinolones > Sulfonamides > Chloramphenicols > β-Lactams > Macrolides. The adsorption mechanism was proposed to be electrostatic attraction, p-π interaction, π-π interaction and hydrogen bonds. In detail, the adsorption capacities of CNF/GO aerogel were 418.7 mg·g−1 for chloramphenicol, 291.8 mg·g−1 for macrolides, 128.3 mg·g−1 for quinolones, 230.7 mg·g−1 for β-Lactams, 227.3 mg·g−1 for sulfonamides, and 454.6 mg·g−1 for tetracyclines calculated by the Langmuir isotherm models. Furthermore, the regenerated aerogels still could be repeatedly used after ten cycles without obvious degradation of adsorption performance. PMID:28368045

  19. Real-time and in situ enzyme inhibition assay for the flux of hydrogen sulfide based on 3D interwoven AuPd-reduced graphene oxide network.

    PubMed

    Yang, Hongmei; Zhang, Yan; Li, Li; Sun, Guoqiang; Zhang, Lina; Ge, Shenguang; Yu, Jinghua

    2017-01-15

    A highly sensitive enzyme inhibition analytical platform was established firstly based on paper-supported 3D interwoven AuPd-reduced graphene oxide (rGO) network (NW) for real-time and in situ analysis of H2S released from cancer cells. The novel paper working electrode (PWE) with large electric conductivity, effective surface area and unusual biocompatibility, was fabricated via controllably assembling rGO and AuPd alloy nanoparticles onto the surface of cellulose fibers and into the macropores of paper, which was employed as affinity matrix for horseradish peroxidase (HRP) loading and cells capture. It was the superior performances of AuPd-rGO-NW-PWE that made the loaded HRP exhibit excellent electrocatalytic behavior to H2O2, bring the rapid enhancement of current response. After releasing H2S, the current response would be obviously decreased due to the efficient inhibition effect of H2S on HRP activity. The inhibition degree of HRP was directly proportional to the amount of H2S, and so, the flux of H2S released from cells could be recorded availably. Thus, this proposed enzyme inhibition cyto-sensor could be applied for efficient recording of the release of H2S, which had potential utility to cellular biology and pathophysiology.

  20. Conversion of uniform graphene oxide/polypyrrole composites into functionalized 3D carbon nanosheet frameworks with superior supercapacitive and sodium-ion storage properties

    NASA Astrophysics Data System (ADS)

    Wang, Huanwen; Zhang, Yu; Sun, Wenping; Tan, Hui Teng; Franklin, Joseph B.; Guo, Yuanyuan; Fan, Haosen; Ulaganathan, Mani; Wu, Xing-Long; Luo, Zhong-Zhen; Madhavi, Srinivasan; Yan, Qingyu

    2016-03-01

    Two-dimensional (2D) graphene oxide/polypyrrole (GO/PPy) hybrid materials derived from in-situ polymerization are used as precursors for constructing functionalized three-dimensional (3D) porous nitrogen-doped carbon nanosheet frameworks (FT-PNCNFs) through a one-step activation strategy. In the formation process of FT-PNCNFs, PPY is directly converted into hierarchical porous nitrogen-doped carbon layers, while GO is simultaneously reduced to become electrically conductive. The complementary functions of individual components endow the FT-PNCNFs with excellent properties for both supercapacitors (SCs) and sodium ion batteries (SIBs) applications. When tested in symmetrical SC, the FT-PNCNFs demonstrate superior energy storage behaviour. At an extremely high scan rate of 3000 mV s-1, the cyclic voltammetry (CV) curve retains an inspiring quasi-rectangle shape in KOH solution. Meanwhile, high capacitances (∼247 F g-1 at 10 mV s-1; ∼146 F g-1 at 3000 mV s-1) and good cycling stability (∼95% retention after 8000 cycles) are achieved. In addition, an attractive SIB anode performance could be achieved. The FT-PNCNFs electrode delivers a reversible capacity of 187 mAh g-1 during 160th cycle at 100 mA g-1. Its reversible capacity retains 144 mAh g-1 after extending the number of cycles to 500 at 500 mA g-1.

  1. 3D assembly based on 2D structure of Cellulose Nanofibril/Graphene Oxide Hybrid Aerogel for Adsorptive Removal of Antibiotics in Water.

    PubMed

    Yao, Qiufang; Fan, Bitao; Xiong, Ye; Jin, Chunde; Sun, Qingfeng; Sheng, Chengmin

    2017-04-03

    Cellulose nanofibril/graphene oxide hybrid (CNF/GO) aerogel was fabricated via a one-step ultrasonication method for adsorptive removal of 21 kinds of antibiotics in water. The as-prepared CNF/GO aerogel possesses interconnected 3D network microstructure, in which GO nanosheets with 2D structure were intimately grown along CNF through hydrogen bonds. The aerogel exhibited superior adsorption capacity toward the antibiotics. The removal percentages (R%) of the antibiotics were more than 69% and the sequence of six categories antibiotics according to the adsorption efficiency was as follows: Tetracyclines > Quinolones > Sulfonamides > Chloramphenicols > β-Lactams > Macrolides. The adsorption mechanism was proposed to be electrostatic attraction, p-π interaction, π-π interaction and hydrogen bonds. In detail, the adsorption capacities of CNF/GO aerogel were 418.7 mg·g(-1) for chloramphenicol, 291.8 mg·g(-1) for macrolides, 128.3 mg·g(-1) for quinolones, 230.7 mg·g(-1) for β-Lactams, 227.3 mg·g(-1) for sulfonamides, and 454.6 mg·g(-1) for tetracyclines calculated by the Langmuir isotherm models. Furthermore, the regenerated aerogels still could be repeatedly used after ten cycles without obvious degradation of adsorption performance.

  2. Foam Microrheology

    SciTech Connect

    KRAYNIK,ANDREW M.; LOEWENBERG,MICHAEL; REINELT,DOUGLAS A.

    1999-09-01

    The microrheology of liquid foams is discussed for two different regimes: static equilibrium where the capillary number Ca is zero, and the viscous regime where viscosity and surface tension are important and Ca is finite. The Surface Evolver is used to calculate the equilibrium structure of wet Kelvin foams and dry soap froths with random structure, i.e., topological disorder. The distributions of polyhedra and faces are compared with the experimental data of Matzke. Simple shearing flow of a random foam under quasistatic conditions is also described. Viscous phenomena are explored in the context of uniform expansion of 2D and 3D foams at low Reynolds number. Boundary integral methods are used to calculate the influence of Ca on the evolution of foam microstructure, which includes bubble shape and the distribution of liquid between films, Plateau borders, and (in 3D) the nodes where Plateau borders meet. The micromechanical point of view guides the development of structure-property-processing relationships for foams.

  3. Hierarchical 3D ZnIn2S4/graphene nano-heterostructures: their in situ fabrication with dual functionality in solar hydrogen production and as anodes for lithium ion batteries.

    PubMed

    Kale, Sayali B; Kalubarme, Ramchandra S; Mahadadalkar, Manjiri A; Jadhav, Harsharaj S; Bhirud, Ashwini P; Ambekar, Jalinder D; Park, Chan-Jin; Kale, Bharat B

    2015-12-21

    Hierarchical 3D ZnIn2S4/graphene (ZnIn2S4/Gr) nano-heterostructures were successfully synthesized using an in-situ hydrothermal method. The dual functionality of these nano-heterostructures i.e. for solar hydrogen production and lithium ion batteries has been demonstrated for the first time. The ZnIn2S4/Gr nano-heterostructures were optimized by varying the concentrations of graphene for utmost hydrogen production. An inspection of the structure shows the existence of layered hexagonal ZnIn2S4 wrapped in graphene. The reduction of graphene oxide (GO) to graphene was confirmed by Raman and XPS analyses. The morphological analysis demonstrated that ultrathin ZnIn2S4 nanopetals are dispersed on graphene sheets. The optical study reveals the extended absorption edge to the visible region due to the presence of graphene and hence is used as a photocatalyst to transform H2S into eco-friendly hydrogen using solar light. The ZnIn2S4/Gr nano-heterostructure that is comprised of graphene and ZnIn2S4 in a weight ratio of 1 : 99 exhibits enhanced photocatalytically stable hydrogen production i.e. ∼6365 μmole h(-1) under visible light irradiation using just 0.2 g of nano-heterostructure, which is much higher as compared to bare hierarchical 3D ZnIn2S4. The heightened photocatalytic activity is attributed to the enhanced charge carrier separation due to graphene which acts as an excellent electron collector and transporter. Furthermore, the usage of nano-heterostructures and pristine ZnIn2S4 as anodes in lithium ion batteries confers the charge capacities of 590 and 320 mA h g(-1) after 220 cycles as compared to their initial reversible capacities of 645 and 523 mA h g(-1), respectively. These nano-heterostructures show high reversible capacity, excellent cycling stability, and high-rate capability indicating their potential as promising anode materials for LIBs. The excellent performance is due to the nanostructuring of ZnIn2S4 and the presence of a graphene layer, which

  4. A flexible alkaline rechargeable Ni/Fe battery based on graphene foam/carbon nanotubes hybrid film.

    PubMed

    Liu, Jilei; Chen, Minghua; Zhang, Lili; Jiang, Jian; Yan, Jiaxu; Huang, Yizhong; Lin, Jianyi; Fan, Hong Jin; Shen, Ze Xiang

    2014-12-10

    The development of portable and wearable electronics has promoted increasing demand for high-performance power sources with high energy/power density, low cost, lightweight, as well as ultrathin and flexible features. Here, a new type of flexible Ni/Fe cell is designed and fabricated by employing Ni(OH)2 nanosheets and porous Fe2O3 nanorods grown on lightweight graphene foam (GF)/carbon nanotubes (CNTs) hybrid films as electrodes. The assembled f-Ni/Fe cells are able to deliver high energy/power densities (100.7 Wh/kg at 287 W/kg and 70.9 Wh/kg at 1.4 kW/kg, based on the total mass of active materials) and outstanding cycling stabilities (retention 89.1% after 1000 charge/discharge cycles). Benefiting from the use of ultralight and thin GF/CNTs hybrid films as current collectors, our f-Ni/Fe cell can exhibit a volumetric energy density of 16.6 Wh/l (based on the total volume of full cell), which is comparable to that of thin film battery and better than that of typical commercial supercapacitors. Moreover, the f-Ni/Fe cells can retain the electrochemical performance with repeated bendings. These features endow our f-Ni/Fe cells a highly promising candidate for next generation flexible energy storage systems.

  5. A novel asymmetric supercapacitors based on binder-free carbon fiber paper@ nickel cobaltite nanowires and graphene foam electrodes

    NASA Astrophysics Data System (ADS)

    Tang, Qianqiu; Chen, Mingming; Wang, Le; Wang, Gengchao

    2015-01-01

    Aqueous-based asymmetric supercapacitors (AASCs) provide an effective way to improve the energy density of the device by broadening the operating voltage window. In this work, nickel cobaltite (NiCo2O4) nanowires are grown homogenously on carbon fiber paper (CFP) to obtain a binder-free CFP@NiCo2O4 positive electrode through a simple hydrothermal method followed by calcination. The highly porous graphene foam (GF) as negative electrode which also exhibits self-supporting structure is prepared by a facile mild reduction process. Taking advantages of the complementary voltage window of CFP@NiCo2O4 and GF, the as-fabricated CFP@NiCo2O4//GF AASC obtains a stable working voltage window of 1.6 V, and a high energy density of 34.5 Wh kg-1 at the power density of 547 W kg-1, which still maintains 17.1 Wh kg-1 at 9.68 kW kg-1. Furthermore, it exhibits superior cycling performance with 92.2% capacitance retention rate after 10000 cycles.

  6. Solvothermal synthesis of NiAl double hydroxide microspheres on a nickel foam-graphene as an electrode material for pseudo-capacitors

    SciTech Connect

    Momodu, Damilola; Bello, Abdulhakeem; Dangbegnon, Julien; Barzeger, Farshad; Taghizadeh, Fatimeh; Fabiane, Mopeli; Manyala, Ncholu; Johnson, A. T. Charlie

    2014-09-15

    In this paper, we demonstrate excellent pseudo-capacitance behavior of nickel-aluminum double hydroxide microspheres (NiAl DHM) synthesized by a facile solvothermal technique using tertbutanol as a structure-directing agent on nickel foam-graphene (NF-G) current collector as compared to use of nickel foam current collector alone. The structure and surface morphology were studied by X-ray diffraction analysis, Raman spectroscopy and scanning and transmission electron microscopies respectively. NF-G current collector was fabricated by chemical vapor deposition followed by an ex situ coating method of NiAl DHM active material which forms a composite electrode. The pseudocapacitive performance of the composite electrode was investigated by cyclic voltammetry, constant charge–discharge and electrochemical impedance spectroscopy measurements. The composite electrode with the NF-G current collector exhibits an enhanced electrochemical performance due to the presence of the conductive graphene layer on the nickel foam and gives a specific capacitance of 1252 F g{sup −1} at a current density of 1 A g{sup −1} and a capacitive retention of about 97% after 1000 charge–discharge cycles. This shows that these composites are promising electrode materials for energy storage devices.

  7. Improved wetting behavior and thermal conductivity of the three-dimensional nickel foam/epoxy composites with graphene oxide as interfacial modifier

    NASA Astrophysics Data System (ADS)

    Huang, Liang; Zhu, Pengli; Li, Gang; Sun, Rong

    2016-05-01

    The partial reduced graphene oxide (P-rGO) sheets-wrapped nickel foams (NF@P-rGO) were prepared by hydrothermal method, and then their epoxy composites were fabricated via a simple drop-wetting process. The P-rGO sheets on the metal networks could effectively improve the compatibility between nickel foam and epoxy resin, thus greatly accelerate the wetting of epoxy resin on the foams and avoid cracks in the network-polymer interface. Owing to the existence of high-efficiency conductive metal networks, the NF@P-rGO/epoxy composite has a high thermal conductivity of 0.584 W m-1 K-1, which is 2.6 times higher than that of neat epoxy resin. Additionally, owing to the improved wetting ability, NF@P-rGO-10 wt% boron nitride (BN) microsheets/epoxy composites could be fabricated and have a further higher thermal conductivity of 0.71 W m-1 K-1. We believe the use of P-rGO as a novel surface modifier and the following liquid polymer drop-wetting could be an effective method to obtain novel and outstanding metal foam/polymer composites.

  8. 1.5 V battery driven reduced graphene oxide-silver nanostructure coated carbon foam (rGO-Ag-CF) for the purification of drinking water

    NASA Astrophysics Data System (ADS)

    Kumar, Surender; Ghosh, Somnath; Munichandraiah, N.; Vasan, H. N.

    2013-06-01

    A porous carbon foam (CF) electrode modified with a reduced graphene oxide-Ag (rGO-Ag) nanocomposite has been fabricated to purify water. It can perform as an antibacterial device by killing pathogenic microbes with the aid of a 1.5 V battery, with very little power consumption. The device is recycled ten times with good performance for long term usage. It is shown that the device may be implemented as a fast water purifier to deactivate the pathogens in drinking water.

  9. 1.5 V battery driven reduced graphene oxide-silver nanostructure coated carbon foam (rGO-Ag-CF) for the purification of drinking water.

    PubMed

    Kumar, Surender; Ghosh, Somnath; Munichandraiah, N; Vasan, H N

    2013-06-14

    A porous carbon foam (CF) electrode modified with a reduced graphene oxide-Ag (rGO-Ag) nanocomposite has been fabricated to purify water. It can perform as an antibacterial device by killing pathogenic microbes with the aid of a 1.5 V battery, with very little power consumption. The device is recycled ten times with good performance for long term usage. It is shown that the device may be implemented as a fast water purifier to deactivate the pathogens in drinking water.

  10. An electrochemical sensor for simultaneous determination of ascorbic acid, dopamine, uric acid and tryptophan based on MWNTs bridged mesocellular graphene foam nanocomposite.

    PubMed

    Li, Huixiang; Wang, Yi; Ye, Daixin; Luo, Juan; Su, Biquan; Zhang, Song; Kong, Jilie

    2014-09-01

    A multi-walled carbon nanotubes (MWNTs) bridged mesocellular graphene foam (MGF) nanocomposite (MWNTs/MGF) modified glassy carbon electrode was fabricated and successfully used for simultaneous determination of ascorbic acid (AA), dopamine (DA), uric acid (UA) and tryptophan (TRP). Comparing with pure MGF, MWNTs or MWNTs/GS (graphene sheets), MWNTs/MGF displayed higher catalytic activity and selectivity toward the oxidation of AA, DA, UA and TRP. Under the optimal conditions, MWCNs/MGF/GCE can simultaneously detect AA, DA, UA and TRP with high selectivity and sensitivity. The detection limits were 18.28 µmol L(-1), 0.06 µmol L(-1), 0.93 µmol L(-1) and 0.87 µmol L(-1), respectively. Moreover, the modified electrode exhibited excellent stability and reproducibility.

  11. Foam Micromechanics

    SciTech Connect

    Kraynik, A.M.; Neilsen, M.K.; Reinelt, D.A.; Warren, W.E.

    1998-11-03

    -dimensional situation is always easier to visualize and usually easier to analyze, the roots of foam micromechanics lie in the plane packed with polygons. There are striking similarities as well as obvious differences between 2D and 3D.

  12. General formation of three-dimensional (3D) interconnected MxSy (M = Ni, Zn, and Fe)-graphene nanosheets-carbon nanotubes aerogels for lithium-ion batteries with excellent rate capability and cycling stability

    NASA Astrophysics Data System (ADS)

    Wang, Xiujuan; Liu, Xiaojie; Wang, Gang; Zhou, Yixuan; Wang, Hui

    2017-02-01

    Metal sulfides have a highly promising potential as anode materials for next-generation lithium-ion batteries (LIBs) due to their environmental friendliness, abundant resources, and low-cost. Unfortunately, the implementation of such novel anodes is severely hindered by their low electronic conductivity and large volume expansion during the repetitive lithiation/delithiation process. Herein, we report a specifically designed anode structure to overcome these obstacles, that is, to incorporate MxSy (M = Ni, Zn, and Fe) with graphene nanosheets (GNS) and carbon nanotubes (CNTs) to form three-dimensional interconnected MxSy-graphene nanosheets-carbon nanotubes aerogels. Morphology and structure results confirm that MxSy particles were uniformly and closely attached on the 3D complex network structure of GNS-CNT. As a result, when used as anode materials for half and full LIBs, the MxSy-GNS-CNT aerogels exhibit remarkable high reversible capacities, ultra-long cycle life, and super high rate performance (For example, the NiS-GNS-CNT, ZnS-GNS-CNT, and FeS2-GNS-CNT aerogels could deliver high capacities of 735, 800, and 850 mAh g-1 after 100 cycles, respectively). Our results indicate that 3D interconnected MxSy-GNS-CNT aerogels are promising anode materials for the next generation LIBs with high-performance.

  13. Facile synthesis of Fe3O4 nanoparticles decorated on 3D graphene aerogels as broad-spectrum sorbents for water treatment

    NASA Astrophysics Data System (ADS)

    Li, Yong; Zhang, Ruofang; Tian, Xike; Yang, Chao; Zhou, Zhaoxin

    2016-04-01

    In order to develop efficient and environment benign sorbents for water purification, the macroscopic multifunctional magnetite-reduced graphene oxides aerogels (M-RGOs) with strong interconnected networks were prepared via a one pot solvothermal method of graphene oxide sheets adsorbing iron ions and in situ simultaneous deposition of Fe3O4 nanoparticles in ethylene glycol or triethylene glycol solvents. Such M-RGOs exhibited excellent sorption capacity to different contaminants, including oils, organic solvents, arsenite ions, as well as dyes. In addition, it was demonstrated that the M-RGOs could be used as column packing materials to manufacture column for water purification by filtration. The method proposed was proved to be versatile to induce synergistic assembly of RGO sheets with other functional metal oxides nanoparticles and as a kind of broad-spectrum sorbents for removing different types of contaminants in water purification, simultaneously.

  14. 3D Porous Graphene Aerogel Cathode with High Sulfur Loading and Embedded TiO2 Nanoparticles for Advanced Lithium-Sulfur Batteries.

    PubMed

    Huang, Jian-Qiu; Wang, Zhenyu; Xu, Zheng-Long; Chong, Woon Gie; Qin, Xianying; Wang, Xiangyu; Kim, Jang-Kyo

    2016-10-07

    Three-dimensional graphene aerogel/TiO2/sulfur (GA/TiO2/S) composites are synthesized through a facile, one-pot hydrothermal route as the cathode for lithium-sulfur batteries. With a high sulfur content of 75.1 wt%, the conductive, highly porous composite electrode delivers a high discharge capacity of 512 mAh/g after 250 cycles at a current rate of 1 C with a low capacity decay of 0.128% per cycle. The excellent capacities and cyclic stability arise from several unique functional features of the cathode. (i) The conductive graphene aerogel framework ameliorates ion/electron transfer while accommodating the volume expansion induced during discharge; and (ii) TiO2 nanoparticles play an important role in restricting the dissolution of polysulfides by chemical bonds with sulfur.

  15. Nano-Composite Material Development for 3-D Printers

    SciTech Connect

    Satches, Michael Randolph

    2015-10-14

    The objectives of the project was to create a graphene reinforced polymer nano-composite viable in a commercial 3-D printer; study the effects of ultra-high loading of graphene in polymer matrices; and determine the functional upper limit of graphene loading.

  16. Surfactant-assisted fabrication of 3D Prussian blue-reduced graphene oxide hydrogel as a self-propelling motor for water treatment

    NASA Astrophysics Data System (ADS)

    Hao, Jinhui; Yang, Wenshu; Zhang, Zhe; Tang, Jilin

    2015-06-01

    Three-dimensional Prussian blue-reduced graphene oxide hydrogel was synthesized with the assistance of sodium dodecyl sulfate (SDS) through a facile hydrothermal method. The hydrogel exhibited strong mechanical properties and was successfully applied as a self-propelling motor for water treatment. During the self-propelling degradation process, SDS facilitated the rapid liberation of oxygen bubbles from the motor and the oxygen bubbles assisted the rapid diffusion of hydroxyl radicals. In addition, the well-defined structure increased the number of reaction sites and the synergy between reduced graphene oxide and Prussian blue, which accelerated the degradation efficiency. The self-propelling motor had an average velocity of 0.026 +/- 0.013 cm s-1 in 7.5% H2O2 and 0.069 +/- 0.032 cm s-1 in 22.5% H2O2. Moreover, the self-propelling motor maintained high degradation efficiency even after cycling for 9 times. These excellent properties make the self-propelling motor an ideal candidate for water treatment.Three-dimensional Prussian blue-reduced graphene oxide hydrogel was synthesized with the assistance of sodium dodecyl sulfate (SDS) through a facile hydrothermal method. The hydrogel exhibited strong mechanical properties and was successfully applied as a self-propelling motor for water treatment. During the self-propelling degradation process, SDS facilitated the rapid liberation of oxygen bubbles from the motor and the oxygen bubbles assisted the rapid diffusion of hydroxyl radicals. In addition, the well-defined structure increased the number of reaction sites and the synergy between reduced graphene oxide and Prussian blue, which accelerated the degradation efficiency. The self-propelling motor had an average velocity of 0.026 +/- 0.013 cm s-1 in 7.5% H2O2 and 0.069 +/- 0.032 cm s-1 in 22.5% H2O2. Moreover, the self-propelling motor maintained high degradation efficiency even after cycling for 9 times. These excellent properties make the self-propelling motor an

  17. Core-Shell Co/CoO Integrated on 3D Nitrogen Doped Reduced Graphene Oxide Aerogel as an Enhanced Electrocatalyst for the Oxygen Reduction Reaction

    PubMed Central

    Wang, Meng; Hou, Yuyang; Slade, Robert C. T.; Wang, Jiazhao; Shi, Dongqi; Wexler, David; Liu, Huakun; Chen, Jun

    2016-01-01

    Here, we demonstrate that Cobalt/cobalt oxide core-shell nanoparticles integrated on nitrogen-doped (N-doped) three-dimensional reduced graphene oxide aerogel-based architecture (Co/CoO-NGA) were synthesized through a facile hydrothermal method followed by annealing treatment. The unique endurable porous structure could provide sufficient mass transfer channels and ample active sites on Co/CoO-NGA to facilitate the catalytic reaction. The synthesized Co/CoO-NGA was explored as an electrocatalyst for the oxygen reduction reaction, showing comparable oxygen reduction performance with excellent methanol resistance and better durability compared with Pt/C. PMID:27597939

  18. Nanohoneycomb-like manganese cobalt sulfide/three dimensional graphene-nickel foam hybid electrodes for high-rate capability supercapacitors

    NASA Astrophysics Data System (ADS)

    Yu, Mei; Li, Xinjie; Ma, Yuxiao; Liu, Ruili; Liu, Jianhua; Li, Songmei

    2017-02-01

    Nanohoneycomb-like manganese cobalt sulfide/three dimensional graphene-nickel foam hybrid electrodes for supercapacitor are synthesized by chemical vapor deposition and electrodeposition. The ternary sulfide electrode exhibits high specific capacitance (1938 F g-1 at 5 A g-1) with excellent rate capability (76.8% capacitance retention at 100 A g-1) due to the intercrossed feature of the nanowalls and three-dimensional interpenetrating nanoarchitecture. Moreover, the specific capacitance of the electrode after 4000 cycles at a high current density of 50 A g-1 is 1320 F g-1. The asymmetric supercapacitor assembled with the manganese cobalt sulfide electrode and an activated carbon electrode displays an energy density of 14.33 W h kg-1 at a power density of 74.87 W kg-1. The manganese cobalt sulfide is a promising electrode material for practical application.

  19. Electrohydrodynamic-assisted Assembly of Hierarchically Structured, 3D Crumpled Nanostructures for Efficient Solar Conversions

    PubMed Central

    Ishihara, Hidetaka; Chen, Yen-Chang; De Marco, Nicholas; Lin, Oliver; Huang, Chih-Meng; Limsakoune, Vipawee; Chou, Yi-Chia; Yang, Yang; Tung, Vincent

    2016-01-01

    The tantalizing prospect of harnessing the unique properties of graphene crumpled nanostructures continues to fuel tremendous interest in energy storage and harvesting applications. However, the paper ball-like, hard texture, and closed-sphere morphology of current 3D graphitic nanostructure production not only constricts the conductive pathways but also limits the accessible surface area. Here, we report new insights into electrohydrodynamically-generated droplets as colloidal nanoreactors in that the stimuli-responsive nature of reduced graphene oxide can lead to the formation of crumpled nanostructures with a combination of open structures and doubly curved, saddle-shaped edges. In particular, the crumpled nanostructures dynamically adapt to non-spherical, polyhedral shapes under continuous deposition, ultimately assembling into foam-like microstructures with a highly accessible surface area and spatially interconnected transport pathways. The implementation of such crumpled nanostructures as three-dimensional rear contacts for solar conversion applications realize benefits of a high aspect ratio, electrically addressable and energetically favorable interfaces, and substantial enhancement of both short-circuit currents and fill-factors compared to those made of planar graphene counterparts. Further, the 3D crumpled nanostructures may shed lights onto the development of effective electrocatalytic electrodes due to their open structure that simultaneously allows for efficient water flow and hydrogen escape. PMID:27924857

  20. Electrohydrodynamic-assisted Assembly of Hierarchically Structured, 3D Crumpled Nanostructures for Efficient Solar Conversions

    NASA Astrophysics Data System (ADS)

    Ishihara, Hidetaka; Chen, Yen-Chang; De Marco, Nicholas; Lin, Oliver; Huang, Chih-Meng; Limsakoune, Vipawee; Chou, Yi-Chia; Yang, Yang; Tung, Vincent

    2016-12-01

    The tantalizing prospect of harnessing the unique properties of graphene crumpled nanostructures continues to fuel tremendous interest in energy storage and harvesting applications. However, the paper ball-like, hard texture, and closed-sphere morphology of current 3D graphitic nanostructure production not only constricts the conductive pathways but also limits the accessible surface area. Here, we report new insights into electrohydrodynamically-generated droplets as colloidal nanoreactors in that the stimuli-responsive nature of reduced graphene oxide can lead to the formation of crumpled nanostructures with a combination of open structures and doubly curved, saddle-shaped edges. In particular, the crumpled nanostructures dynamically adapt to non-spherical, polyhedral shapes under continuous deposition, ultimately assembling into foam-like microstructures with a highly accessible surface area and spatially interconnected transport pathways. The implementation of such crumpled nanostructures as three-dimensional rear contacts for solar conversion applications realize benefits of a high aspect ratio, electrically addressable and energetically favorable interfaces, and substantial enhancement of both short-circuit currents and fill-factors compared to those made of planar graphene counterparts. Further, the 3D crumpled nanostructures may shed lights onto the development of effective electrocatalytic electrodes due to their open structure that simultaneously allows for efficient water flow and hydrogen escape.

  1. Electrohydrodynamic-assisted Assembly of Hierarchically Structured, 3D Crumpled Nanostructures for Efficient Solar Conversions.

    PubMed

    Ishihara, Hidetaka; Chen, Yen-Chang; De Marco, Nicholas; Lin, Oliver; Huang, Chih-Meng; Limsakoune, Vipawee; Chou, Yi-Chia; Yang, Yang; Tung, Vincent

    2016-12-07

    The tantalizing prospect of harnessing the unique properties of graphene crumpled nanostructures continues to fuel tremendous interest in energy storage and harvesting applications. However, the paper ball-like, hard texture, and closed-sphere morphology of current 3D graphitic nanostructure production not only constricts the conductive pathways but also limits the accessible surface area. Here, we report new insights into electrohydrodynamically-generated droplets as colloidal nanoreactors in that the stimuli-responsive nature of reduced graphene oxide can lead to the formation of crumpled nanostructures with a combination of open structures and doubly curved, saddle-shaped edges. In particular, the crumpled nanostructures dynamically adapt to non-spherical, polyhedral shapes under continuous deposition, ultimately assembling into foam-like microstructures with a highly accessible surface area and spatially interconnected transport pathways. The implementation of such crumpled nanostructures as three-dimensional rear contacts for solar conversion applications realize benefits of a high aspect ratio, electrically addressable and energetically favorable interfaces, and substantial enhancement of both short-circuit currents and fill-factors compared to those made of planar graphene counterparts. Further, the 3D crumpled nanostructures may shed lights onto the development of effective electrocatalytic electrodes due to their open structure that simultaneously allows for efficient water flow and hydrogen escape.

  2. Self-Construction from 2D to 3D: One-Pot Layer-by-Layer Assembly of Graphene Oxide Sheets Held Together by Coordination Polymers.

    PubMed

    Zakaria, Mohamed B; Li, Cuiling; Ji, Qingmin; Jiang, Bo; Tominaka, Satoshi; Ide, Yusuke; Hill, Jonathan P; Ariga, Katsuhiko; Yamauchi, Yusuke

    2016-07-11

    Deposition of Ni-based cyanide bridged coordination polymer (NiCNNi) flakes onto the surfaces of graphene oxide (GO) sheets, which allows precise control of the resulting lamellar nanoarchitecture by in situ crystallization, is reported. GO sheets are utilized as nucleation sites that promote the optimized crystal growth of NiCNNi flakes. The NiCNNi-coated GO sheets then self-assemble and are stabilized as ordered lamellar nanomaterials. Regulated thermal treatment under nitrogen results in a Ni3 C-GO composite with a similar morphology to the starting material, and the Ni3 C-GO composite exhibits outstanding electrocatalytic activity and excellent durability for the oxygen reduction reaction.

  3. Ni(OH){sub 2} nanoflakes electrodeposited on Ni foam-supported vertically oriented graphene nanosheets for application in asymmetric supercapacitors

    SciTech Connect

    Wang, Xin; Liu, Jiyue; Wang, Yayu; Zhao, Cuimei; Zheng, Weitao

    2014-04-01

    Highlights: • Ni(OH){sub 2}/vertically oriented graphene nanosheets (V-GNs) was prepared. • Ni(OH){sub 2}/V-GNs had enhanced specific capacitance, cycling reversibility and stability. • Performance of Ni(OH){sub 2}/GNs/NF-AC asymmetric supercapacitor was studied. - Abstract: Binderless Ni(OH){sub 2} nanoflakes grown on Ni foam (NF)-supported vertically oriented graphene nanosheets (V-GNs) has been fabricated as a positive electrode material for asymmetric supercapacitor (ASC), coupled with activated carbon (AC) as a counter electrode material. The introduction of V-GNs leads to dense growth of nanocrystalline β-Ni(OH){sub 2} that is confirmed by X-ray diffraction, transmission electron microscopic and scanning electron microscopic analyses. The electrochemical performances of the Ni(OH){sub 2}/GNs/NF electrode are characterized by cyclic voltammetry and charge–discharge tests, which exhibit high specific capacitance of 2215 F g{sup −1} at a scan current density of 2.3 A g{sup −1}, enhanced cycling stability and high rate capability. The Ni(OH){sub 2}/GNs/NF-AC-based ASC can achieve a cell voltage of 1.4 V and a specific energy density of 11.11 Wh kg{sup −1} at 0.5 mA cm{sup −2} with a nearly 100% coulombic efficiency at room temperature.

  4. Advanced 3D Ni(OH)2/CNT Gel Composite Electrodes for Supercapacitors

    NASA Astrophysics Data System (ADS)

    Cheng, Hanlin; Duong, Hai Minh

    2015-03-01

    In order to enhance the performance of supercapacitors, advanced 3D Porous CNT/Ni(OH)2 gel composite electrodes are developed in this work. Compared with previously reported graphene gel supercapacitors, our electrodes using 1D CNTs have smaller diffusion resistance due to a shorter ion transport path. The developed 3D xerogel composite electrodes demonstrate the success of a careful engineered guest/host materials interface. Initially, the CNT gels are coated on the nickel foam to form a 3D scaffold, which serves as a microscopic electrical conductive network. Then Ni(OH)2 are incorporated using a traditional electrodeposition method. In this work, two types of the 3D CNT-coated nickel foams are investigated. The gels can be used directly as hydrogels or dried in air to form xerogels. Both hydrogels and xerogels present 3D tangled CNT networks. It shows that the hydrogel composite electrodes with unbundled CNTs, though presenting high capacitances of 1400 F/g at low discharge rate, possess lower capacitances at higher discharge rate and a poor cycling performance of less than 23% retention. In contrast, the xerogel composite electrodes can overcome these limitations in terms of a satisfied discharge performance of 1200 F/g and a good cycling retention more than 85% due to a stronger Ni(OH)2/CNT interface. The CNT bundles in the xerogel electrodes formed during the drying process can give a flat surface with small curvature, which facilitate the Ni(OH)2 nucleation and growth. Thanks for the support from the A star R-265-000-424-305.

  5. Europeana and 3D

    NASA Astrophysics Data System (ADS)

    Pletinckx, D.

    2011-09-01

    The current 3D hype creates a lot of interest in 3D. People go to 3D movies, but are we ready to use 3D in our homes, in our offices, in our communication? Are we ready to deliver real 3D to a general public and use interactive 3D in a meaningful way to enjoy, learn, communicate? The CARARE project is realising this for the moment in the domain of monuments and archaeology, so that real 3D of archaeological sites and European monuments will be available to the general public by 2012. There are several aspects to this endeavour. First of all is the technical aspect of flawlessly delivering 3D content over all platforms and operating systems, without installing software. We have currently a working solution in PDF, but HTML5 will probably be the future. Secondly, there is still little knowledge on how to create 3D learning objects, 3D tourist information or 3D scholarly communication. We are still in a prototype phase when it comes to integrate 3D objects in physical or virtual museums. Nevertheless, Europeana has a tremendous potential as a multi-facetted virtual museum. Finally, 3D has a large potential to act as a hub of information, linking to related 2D imagery, texts, video, sound. We describe how to create such rich, explorable 3D objects that can be used intuitively by the generic Europeana user and what metadata is needed to support the semantic linking.

  6. 3d-3d correspondence revisited

    DOE PAGES

    Chung, Hee -Joong; Dimofte, Tudor; Gukov, Sergei; ...

    2016-04-21

    In fivebrane compactifications on 3-manifolds, we point out the importance of all flat connections in the proper definition of the effective 3d N = 2 theory. The Lagrangians of some theories with the desired properties can be constructed with the help of homological knot invariants that categorify colored Jones polynomials. Higgsing the full 3d theories constructed this way recovers theories found previously by Dimofte-Gaiotto-Gukov. As a result, we also consider the cutting and gluing of 3-manifolds along smooth boundaries and the role played by all flat connections in this operation.

  7. The mechanics and design of a lightweight three-dimensional graphene assembly

    PubMed Central

    Qin, Zhao; Jung, Gang Seob; Kang, Min Jeong; Buehler, Markus J.

    2017-01-01

    Recent advances in three-dimensional (3D) graphene assembly have shown how we can make solid porous materials that are lighter than air. It is plausible that these solid materials can be mechanically strong enough for applications under extreme conditions, such as being a substitute for helium in filling up an unpowered flight balloon. However, knowledge of the elastic modulus and strength of the porous graphene assembly as functions of its structure has not been available, preventing evaluation of its feasibility. We combine bottom-up computational modeling with experiments based on 3D-printed models to investigate the mechanics of porous 3D graphene materials, resulting in new designs of carbon materials. Our study reveals that although the 3D graphene assembly has an exceptionally high strength at relatively high density (given the fact that it has a density of 4.6% that of mild steel and is 10 times as strong as mild steel), its mechanical properties decrease with density much faster than those of polymer foams. Our results provide critical densities below which the 3D graphene assembly starts to lose its mechanical advantage over most polymeric cellular materials. PMID:28070559

  8. The mechanics and design of a lightweight three-dimensional graphene assembly.

    PubMed

    Qin, Zhao; Jung, Gang Seob; Kang, Min Jeong; Buehler, Markus J

    2017-01-01

    Recent advances in three-dimensional (3D) graphene assembly have shown how we can make solid porous materials that are lighter than air. It is plausible that these solid materials can be mechanically strong enough for applications under extreme conditions, such as being a substitute for helium in filling up an unpowered flight balloon. However, knowledge of the elastic modulus and strength of the porous graphene assembly as functions of its structure has not been available, preventing evaluation of its feasibility. We combine bottom-up computational modeling with experiments based on 3D-printed models to investigate the mechanics of porous 3D graphene materials, resulting in new designs of carbon materials. Our study reveals that although the 3D graphene assembly has an exceptionally high strength at relatively high density (given the fact that it has a density of 4.6% that of mild steel and is 10 times as strong as mild steel), its mechanical properties decrease with density much faster than those of polymer foams. Our results provide critical densities below which the 3D graphene assembly starts to lose its mechanical advantage over most polymeric cellular materials.

  9. 3D and Education

    NASA Astrophysics Data System (ADS)

    Meulien Ohlmann, Odile

    2013-02-01

    Today the industry offers a chain of 3D products. Learning to "read" and to "create in 3D" becomes an issue of education of primary importance. 25 years professional experience in France, the United States and Germany, Odile Meulien set up a personal method of initiation to 3D creation that entails the spatial/temporal experience of the holographic visual. She will present some different tools and techniques used for this learning, their advantages and disadvantages, programs and issues of educational policies, constraints and expectations related to the development of new techniques for 3D imaging. Although the creation of display holograms is very much reduced compared to the creation of the 90ies, the holographic concept is spreading in all scientific, social, and artistic activities of our present time. She will also raise many questions: What means 3D? Is it communication? Is it perception? How the seeing and none seeing is interferes? What else has to be taken in consideration to communicate in 3D? How to handle the non visible relations of moving objects with subjects? Does this transform our model of exchange with others? What kind of interaction this has with our everyday life? Then come more practical questions: How to learn creating 3D visualization, to learn 3D grammar, 3D language, 3D thinking? What for? At what level? In which matter? for whom?

  10. A sensitive electrochemiluminescence immunosensor based on Ru(bpy)3(2+) in 3D CuNi oxalate as luminophores and graphene oxide-polyethylenimine as released Ru(bpy)3(2+) initiator.

    PubMed

    Li, Xiaojian; Yu, Siqi; Yan, Tao; Zhang, Yong; Du, Bin; Wu, Dan; Wei, Qin

    2017-03-15

    In this work, electrochemiluminescence (ECL) luminophor Ru(bpy)3(2+) was encapsulated in 3D CuNi oxalate and the synthesized metal-inorganic frameworks {[Ru(bpy)3][Cu2xNi2(1-x)(ox)3]}n (Ru/Cu/Ni) exhibited excellent and stable ECL signals, which could be decreased by polyethylenimine capped graphene oxide (GO-PEI). Based on this, a new sandwich ECL immunosensor was developed for detection of carcinoembryonic antigen (CEA). To capture primary antibody and second antibody more simply and efficiently, Ag nanoparticles were doped with Ru/Cu/Ni and GO-PEI. After a sandwich-type immunoreaction, a remarkable decrease of ECL signal was observed due to the release of Ru(bpy)3(2+) which was caused by the coordination between PEI and metal ions. Under the optimization of determination conditions, a linear response range for CEA from 0.1pgmL(-1) to 100ngmL(-1) was obtained, and the detection limit was calculated to be 0.027pgmL(-1) (S/N=3). The prepared CEA immunosensor displayed high sensitivity, excellent stability and good specificity.

  11. Fiber-reinforced syntactic foams

    NASA Astrophysics Data System (ADS)

    Huang, Yi-Jen

    to produce ultralight sandwich core materials was explored in which towpreg (fiber bundles impregnated with resin) were configured to produce 3D pyramidal truss structures. The composite truss structures were subsequently filled with foam to improve resistance to buckling. Mechanical properties of the foam-filled truss structures were measured and contrasted with analytical predictions based on simple truss theory. Results indicated that combination of foams and carbon fiber truss structures had synergistic effects that enhanced the capacity to carry compressive and shear loads.

  12. 3D Imaging.

    ERIC Educational Resources Information Center

    Hastings, S. K.

    2002-01-01

    Discusses 3 D imaging as it relates to digital representations in virtual library collections. Highlights include X-ray computed tomography (X-ray CT); the National Science Foundation (NSF) Digital Library Initiatives; output peripherals; image retrieval systems, including metadata; and applications of 3 D imaging for libraries and museums. (LRW)

  13. Fluid Physics of Foam Evolution and Flow

    NASA Technical Reports Server (NTRS)

    Aref, H.; Thoroddsen, S. T.; Sullivan, J. M.

    2003-01-01

    The grant supported theoretical, numerical and experimental work focused on the elucidation of the fluid physics of foam structure, evolution and flow. The experimental work concentrated on these subject areas: (a) Measurements of the speed of reconnections within a foam; (b) statistics of bubble rearrangements; and (c) three-dimensional reconstruction of the foam structure. On the numerical simulation and theory side our efforts concentrated on the subjects: (a) simulation techniques for 2D and 3D foams; (b) phase transition in a compressible foam; and (c) TCP structures.

  14. AE3D

    SciTech Connect

    Spong, Donald A

    2016-06-20

    AE3D solves for the shear Alfven eigenmodes and eigenfrequencies in a torodal magnetic fusion confinement device. The configuration can be either 2D (e.g. tokamak, reversed field pinch) or 3D (e.g. stellarator, helical reversed field pinch, tokamak with ripple). The equations solved are based on a reduced MHD model and sound wave coupling effects are not currently included.

  15. Springback Foam

    NASA Technical Reports Server (NTRS)

    1979-01-01

    A decade ago, NASA's Ames Research Center developed a new foam material for protective padding of airplane seats. Now known as Temper Foam, the material has become one of the most widely-used spinoffs. Latest application is a line of Temper Foam cushioning produced by Edmont-Wilson, Coshocton, Ohio for office and medical furniture. The example pictured is the Classic Dental Stool, manufactured by Dentsply International, Inc., York, Pennsylvania, one of four models which use Edmont-Wilson Temper Foam. Temper Foam is an open-cell, flameresistant foam with unique qualities.

  16. Synthesis of carbon nanotubes over 3D cubical Co-KIT-6 and nickel decorated graphene by Hummer's method, its application as counter electrode in dye sensitive solar cell

    NASA Astrophysics Data System (ADS)

    Subramanian, Sunu; Pandurangan, Arumugam

    2016-04-01

    The challenges on carbon nanotubes and graphene are still the subject of many research works due to its unique properties. There are three main methods to synthesis carbon nanotubes in which chemical vapor deposition (CVD) method can use for large scale production. The principle of CVD is the decomposition of various hydrocarbons over transition metal supported catalyst. KIT-6 molecular sieve was used as a support to prepare cobalt catalyst for CVD method using metal impregnation method to produce cobalt loadings of 2, 4 and 6 wt%. The catalysts were characterized by XRD, FTIR &TEM. Carbon nanotubes (CNTs) synthesized on Co-KIT-6 was also characterized by XRD, TGA, SEM & Raman spectra. Graphene was synthesized by Hummers method, which is the most common method for preparing graphene oxide. Graphene oxide was prepared by oxidation of graphite using some oxidizing agents like sulphuric acid, sodium nitrate and potassium permanganate. This graphene oxide is further treated with hydrazine solution to convert it into chemically converted graphene and also decorated with nickel metal and characterized. Hummer's method is important for large scale production of graphene. Both Graphene and carbon nanotubes are used in different fields due to its unique properties. Both Graphene and carbon nanotubes are fabricated in counter electrode of Dye sensitized solar cells (DSSC). By cyclic voltammetry study, it confirms that both materials are good and efficient to replace platinum in the DSSC.

  17. Multifunctional nanocomposite foams for space applications

    NASA Astrophysics Data System (ADS)

    Rollins, Diandra J.

    Materials combined with a small amount of nanoparticles offer new possibilities in the synthesizing of multifunctional materials. Graphene nanoplatelets (GnP) are multifunctional nanoreinforcing agents consisting of stacks of graphene sheets with comparable properties to a single graphene layer at an overall lower cost in a more robust form. Such particles have been shown to have good thermal, mechanical and electrical properties. In addition, a low density multifunctional nanocomposite foam has the potential for multiple applications and potential use for the aerospace industry. This dissertation investigates two different microporous (foam) polymers that are modified by the addition of GnP to combat this density effect to improve the foam's macroscopic properties Three sizes of GnP with varying aspect ratio were used to improve the polymeric foams' dielectric, electrical and mechanical properties. (Abstract shortened by ProQuest.).

  18. Advances in cryogenic foam insulations.

    NASA Technical Reports Server (NTRS)

    Lemons, C. R.; Salmassy, O. K.; Watts, C. R.

    1971-01-01

    Description of a discretely oriented thread-reinforced polyurethane foam thermal insulation system for liquid hydrogen fuel tanks. The 3-D foam and glass liner composite is designed to be adhesively bonded to the inside surface of the tank wall and to be in direct contact with liquid hydrogen. All elements of this insulation composite are capable of sustaining the loads and environmental conditions imposed by testing under simulated Space Shuttle vehicle requirements at temperatures between -423 and +350 F.

  19. 3-D Seismic Interpretation

    NASA Astrophysics Data System (ADS)

    Moore, Gregory F.

    2009-05-01

    This volume is a brief introduction aimed at those who wish to gain a basic and relatively quick understanding of the interpretation of three-dimensional (3-D) seismic reflection data. The book is well written, clearly illustrated, and easy to follow. Enough elementary mathematics are presented for a basic understanding of seismic methods, but more complex mathematical derivations are avoided. References are listed for readers interested in more advanced explanations. After a brief introduction, the book logically begins with a succinct chapter on modern 3-D seismic data acquisition and processing. Standard 3-D acquisition methods are presented, and an appendix expands on more recent acquisition techniques, such as multiple-azimuth and wide-azimuth acquisition. Although this chapter covers the basics of standard time processing quite well, there is only a single sentence about prestack depth imaging, and anisotropic processing is not mentioned at all, even though both techniques are now becoming standard.

  20. Radiochromic 3D Detectors

    NASA Astrophysics Data System (ADS)

    Oldham, Mark

    2015-01-01

    Radiochromic materials exhibit a colour change when exposed to ionising radiation. Radiochromic film has been used for clinical dosimetry for many years and increasingly so recently, as films of higher sensitivities have become available. The two principle advantages of radiochromic dosimetry include greater tissue equivalence (radiologically) and the lack of requirement for development of the colour change. In a radiochromic material, the colour change arises direct from ionising interactions affecting dye molecules, without requiring any latent chemical, optical or thermal development, with important implications for increased accuracy and convenience. It is only relatively recently however, that 3D radiochromic dosimetry has become possible. In this article we review recent developments and the current state-of-the-art of 3D radiochromic dosimetry, and the potential for a more comprehensive solution for the verification of complex radiation therapy treatments, and 3D dose measurement in general.

  1. Bootstrapping 3D fermions

    DOE PAGES

    Iliesiu, Luca; Kos, Filip; Poland, David; ...

    2016-03-17

    We study the conformal bootstrap for a 4-point function of fermions <ψψψψ> in 3D. We first introduce an embedding formalism for 3D spinors and compute the conformal blocks appearing in fermion 4-point functions. Using these results, we find general bounds on the dimensions of operators appearing in the ψ × ψ OPE, and also on the central charge CT. We observe features in our bounds that coincide with scaling dimensions in the GrossNeveu models at large N. Finally, we also speculate that other features could coincide with a fermionic CFT containing no relevant scalar operators.

  2. Bootstrapping 3D fermions

    SciTech Connect

    Iliesiu, Luca; Kos, Filip; Poland, David; Pufu, Silviu S.; Simmons-Duffin, David; Yacoby, Ran

    2016-03-17

    We study the conformal bootstrap for a 4-point function of fermions <ψψψψ> in 3D. We first introduce an embedding formalism for 3D spinors and compute the conformal blocks appearing in fermion 4-point functions. Using these results, we find general bounds on the dimensions of operators appearing in the ψ × ψ OPE, and also on the central charge CT. We observe features in our bounds that coincide with scaling dimensions in the GrossNeveu models at large N. Finally, we also speculate that other features could coincide with a fermionic CFT containing no relevant scalar operators.

  3. Venus in 3D

    NASA Technical Reports Server (NTRS)

    Plaut, Jeffrey J.

    1993-01-01

    Stereographic images of the surface of Venus which enable geologists to reconstruct the details of the planet's evolution are discussed. The 120-meter resolution of these 3D images make it possible to construct digital topographic maps from which precise measurements can be made of the heights, depths, slopes, and volumes of geologic structures.

  4. 3D photoacoustic imaging

    NASA Astrophysics Data System (ADS)

    Carson, Jeffrey J. L.; Roumeliotis, Michael; Chaudhary, Govind; Stodilka, Robert Z.; Anastasio, Mark A.

    2010-06-01

    Our group has concentrated on development of a 3D photoacoustic imaging system for biomedical imaging research. The technology employs a sparse parallel detection scheme and specialized reconstruction software to obtain 3D optical images using a single laser pulse. With the technology we have been able to capture 3D movies of translating point targets and rotating line targets. The current limitation of our 3D photoacoustic imaging approach is its inability ability to reconstruct complex objects in the field of view. This is primarily due to the relatively small number of projections used to reconstruct objects. However, in many photoacoustic imaging situations, only a few objects may be present in the field of view and these objects may have very high contrast compared to background. That is, the objects have sparse properties. Therefore, our work had two objectives: (i) to utilize mathematical tools to evaluate 3D photoacoustic imaging performance, and (ii) to test image reconstruction algorithms that prefer sparseness in the reconstructed images. Our approach was to utilize singular value decomposition techniques to study the imaging operator of the system and evaluate the complexity of objects that could potentially be reconstructed. We also compared the performance of two image reconstruction algorithms (algebraic reconstruction and l1-norm techniques) at reconstructing objects of increasing sparseness. We observed that for a 15-element detection scheme, the number of measureable singular vectors representative of the imaging operator was consistent with the demonstrated ability to reconstruct point and line targets in the field of view. We also observed that the l1-norm reconstruction technique, which is known to prefer sparseness in reconstructed images, was superior to the algebraic reconstruction technique. Based on these findings, we concluded (i) that singular value decomposition of the imaging operator provides valuable insight into the capabilities of

  5. Foaming volume and foam stability

    NASA Technical Reports Server (NTRS)

    Ross, Sydney

    1947-01-01

    A method of measuring foaming volume is described and investigated to establish the critical factors in its operation. Data on foaming volumes and foam stabilities are given for a series of hydrocarbons and for a range of concentrations of aqueous ethylene-glycol solutions. It is shown that the amount of foam formed depends on the machinery of its production as well as on properties of the liquid, whereas the stability of the foam produced, within specified mechanical limitations, is primarily a function of the liquid.

  6. Nano-Composite Material Development for 3-D Printers

    SciTech Connect

    Satches, Michael Randolph

    2015-12-01

    Graphene possesses excellent mechanical properties with a tensile strength that may exceed 130 GPa, excellent electrical conductivity, and good thermal properties. Future nano-composites can leverage many of these material properties in an attempt to build designer materials for a broad range of applications. 3-D printing has also seen vast improvements in recent years that have allowed many companies and individuals to realize rapid prototyping for relatively low capital investment. This research sought to create a graphene reinforced, polymer matrix nano-composite that is viable in commercial 3D printer technology, study the effects of ultra-high loading percentages of graphene in polymer matrices and determine the functional upper limit for loading. Loadings varied from 5 wt. % to 50 wt. % graphene nanopowder loaded in Acrylonitrile Butadiene Styrene (ABS) matrices. Loaded sample were characterized for their mechanical properties using three point bending, tensile tests, as well as dynamic mechanical analysis.

  7. Twin Peaks - 3D

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The two hills in the distance, approximately one to two kilometers away, have been dubbed the 'Twin Peaks' and are of great interest to Pathfinder scientists as objects of future study. 3D glasses are necessary to identify surface detail. The white areas on the left hill, called the 'Ski Run' by scientists, may have been formed by hydrologic processes.

    The IMP is a stereo imaging system with color capability provided by 24 selectable filters -- twelve filters per 'eye.

    Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right

  8. 3D and beyond

    NASA Astrophysics Data System (ADS)

    Fung, Y. C.

    1995-05-01

    This conference on physiology and function covers a wide range of subjects, including the vasculature and blood flow, the flow of gas, water, and blood in the lung, the neurological structure and function, the modeling, and the motion and mechanics of organs. Many technologies are discussed. I believe that the list would include a robotic photographer, to hold the optical equipment in a precisely controlled way to obtain the images for the user. Why are 3D images needed? They are to achieve certain objectives through measurements of some objects. For example, in order to improve performance in sports or beauty of a person, we measure the form, dimensions, appearance, and movements.

  9. 3D Audio System

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Ames Research Center research into virtual reality led to the development of the Convolvotron, a high speed digital audio processing system that delivers three-dimensional sound over headphones. It consists of a two-card set designed for use with a personal computer. The Convolvotron's primary application is presentation of 3D audio signals over headphones. Four independent sound sources are filtered with large time-varying filters that compensate for motion. The perceived location of the sound remains constant. Possible applications are in air traffic control towers or airplane cockpits, hearing and perception research and virtual reality development.

  10. 3D Surgical Simulation

    PubMed Central

    Cevidanes, Lucia; Tucker, Scott; Styner, Martin; Kim, Hyungmin; Chapuis, Jonas; Reyes, Mauricio; Proffit, William; Turvey, Timothy; Jaskolka, Michael

    2009-01-01

    This paper discusses the development of methods for computer-aided jaw surgery. Computer-aided jaw surgery allows us to incorporate the high level of precision necessary for transferring virtual plans into the operating room. We also present a complete computer-aided surgery (CAS) system developed in close collaboration with surgeons. Surgery planning and simulation include construction of 3D surface models from Cone-beam CT (CBCT), dynamic cephalometry, semi-automatic mirroring, interactive cutting of bone and bony segment repositioning. A virtual setup can be used to manufacture positioning splints for intra-operative guidance. The system provides further intra-operative assistance with the help of a computer display showing jaw positions and 3D positioning guides updated in real-time during the surgical procedure. The CAS system aids in dealing with complex cases with benefits for the patient, with surgical practice, and for orthodontic finishing. Advanced software tools for diagnosis and treatment planning allow preparation of detailed operative plans, osteotomy repositioning, bone reconstructions, surgical resident training and assessing the difficulties of the surgical procedures prior to the surgery. CAS has the potential to make the elaboration of the surgical plan a more flexible process, increase the level of detail and accuracy of the plan, yield higher operative precision and control, and enhance documentation of cases. Supported by NIDCR DE017727, and DE018962 PMID:20816308

  11. Martian terrain - 3D

    NASA Technical Reports Server (NTRS)

    1997-01-01

    An area of rocky terrain near the landing site of the Sagan Memorial Station can be seen in this image, taken in stereo by the Imager for Mars Pathfinder (IMP) on Sol 3. 3D glasses are necessary to identify surface detail. This image is part of a 3D 'monster' panorama of the area surrounding the landing site.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

    Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right

  12. Structural characterization of solid foams

    NASA Astrophysics Data System (ADS)

    Maire, Éric; Adrien, Jérôme; Petit, Clémence

    2014-10-01

    For being a useful contribution to the understanding of the properties of solid foams, the characterization of the structure of solid foams has to be performed at different scales. The microstructure of the solid part of the foams has to be analyzed. For this, standard SEM observations are often used. The most important aspect (and the most problematic) remains the characterization of the porous architecture of these materials. The methods introduced in this paper concern both scales and the article discusses the specificity of the experiments in the case of porous materials. X-ray tomography is described in more details because it becomes widely used for this purpose. The paper also shows how the obtained 3D images (sometimes obtained during deformation) can be processed to yield important morphological parameters describing the foams. xml:lang="fr"

  13. 3D Surface Topology Guides Stem Cell Adhesion and Differentiation

    PubMed Central

    Viswanathan, Priyalakshmi; Ondeck, Matthew G.; Chirasatitsin, Somyot; Nghamkham, Kamolchanok; Reilly, Gwendolen C.; Engler, Adam J.; Battaglia, Giuseppe

    2015-01-01

    Polymerized high internal phase emulsion (polyHIPE) foams are extremely versatile materials for investigating cell-substrate interactions in vitro. Foam morphologies can be controlled by polymerization conditions to result in either open or closed pore structures with different levels of connectivity, consequently enabling the comparison between 2D and 3D matrices using the same substrate with identical surface chemistry conditions. Additionally, here we achieve the control of pore surface topology (i.e. how different ligands are clustered together) using amphiphilic block copolymers as emulsion stabilisers. We demonstrate that adhesion of human mesenchymal progenitor (hES-MP) cells cultured on polyHIPE foams is dependent on foam surface topology and chemistry but is independent of porosity and interconnectivity. We also demonstrate that the interconnectivity, architecture and surface topology of the foams has an effect on the osteogenic differentiation potential of hES-MP cells. Together these data demonstrate that the adhesive heterogeneity of a 3D scaffold could regulate not only mesenchymal stem cell attachment but also cell behavior in the absence of soluble growth factors. PMID:25818420

  14. 3D field harmonics

    SciTech Connect

    Caspi, S.; Helm, M.; Laslett, L.J.

    1991-03-30

    We have developed an harmonic representation for the three dimensional field components within the windings of accelerator magnets. The form by which the field is presented is suitable for interfacing with other codes that make use of the 3D field components (particle tracking and stability). The field components can be calculated with high precision and reduced cup time at any location (r,{theta},z) inside the magnet bore. The same conductor geometry which is used to simulate line currents is also used in CAD with modifications more readily available. It is our hope that the format used here for magnetic fields can be used not only as a means of delivering fields but also as a way by which beam dynamics can suggest correction to the conductor geometry. 5 refs., 70 figs.

  15. Polyimide foams

    NASA Technical Reports Server (NTRS)

    Gagliani, John (Inventor); Lee, Raymond (Inventor); Sorathia, Usman A. K. (Inventor)

    1982-01-01

    Copolymide foams derived from a diester of 3,3',4,4'-benzophenonetetracarboxylic acid, an aromatic diamine, and a heterocyclic diamine. A molar concentration of the heterocyclic diamine approaching but not exceeding 0.42 is employed. This results in a flexible foam with a homogeneous cellular structure and a reduced compression set loss.

  16. Polyimide foams

    NASA Technical Reports Server (NTRS)

    Gagliani, John (Inventor); Lee, Raymond (Inventor); Sorathia, Usman A. K. (Inventor)

    1982-01-01

    Copolyimide foams derived from a diester of 3,3',4,4'-benzophenonetetracarboxylic acid, an aromatic diamine, and a heterocyclic diamine. A molar concentration of the heterocyclic diamine approaching but not exceeding 0.42 is employed. This results in a flexible foam with a homogeneous cellular structure and a reduced compression set loss.

  17. Polyimide foams

    NASA Technical Reports Server (NTRS)

    Gagliani, John (Inventor); Lee, Raymond (Inventor); Sorathia, Usman A. K. (Inventor)

    1983-01-01

    Copolyimide foams derived from a diester of 3,3',4,4'-benzophenonetetracarboxylic acid, an aromatic diamine, and a heterocyclic diamine. A molar concentration of the heterocyclic diamine approaching but not exceeding 0.42 is employed. This results in a flexible foam with a homogeneous cellular structure and a reduced compression set loss.

  18. Foam clogging.

    PubMed

    Rouyer, F; Haffner, B; Louvet, N; Khidas, Y; Pitois, O

    2014-09-28

    To what extent are aqueous foams prone to clogging? Foam permeability is measured as a function of particulate loading (trapped hydrophilic particles) under conditions where the particle to bubble size ratio is allowed to increase when the number of particles per bubble is fixed. In addition to experiments performed on the foam scale, we investigated experimentally and numerically the hydrodynamic resistance of a single foam node loaded with one particle. It is shown that, with respect to solid porous media, aqueous foams clog more efficiently due to two reasons: (i) the deformation of interfaces allows for larger particles to be incorporated within the interstitial network and (ii) the interfacial mobility contributes to lowering of the reduced permeability.

  19. Composite foams

    DOEpatents

    Williams, Jr., Joel M.; Nyitray, Alice M.; Wilkerson, Mark H.

    1991-01-01

    Composite foams are provided comprising a first rigid, microcellular, open-celled organic polymer foam having a density of from about 0.015 g/cm.sup.3 to about 0.20 g/cm.sup.3 and a pore size of from about 1 micron to about 30 microns, said first foam containing a second polymer having a density of from about 0.015 g/cm.sup.3 to about 0.20 g/cm.sup.3 or a second polymer foam having a density of from about 0.015 g/cm.sup.3 to about 0.20 g/cm.sup.3 and a pore size of from about 0.01 microns to about 1.0 micron within the open cells of said first foam.

  20. Composite foams

    DOEpatents

    Williams, Jr., Joel M.; Nyitray, Alice M.; Wilkerson, Mark H.

    1990-01-01

    Composite foams are provided comprising a first rigid, microcellular, open-celled organic polymer foam having a density of from about 0.015 g/cm.sup.3 to about 0.20 g/cm.sup.3 and a pore size of from about 1 micron to about 30 microns, said first foam containing a second polymer having a density of from about 0.015 g/cm.sup.3 to about 0.20 g/cm.sup.3 or a second polymer foam having a density of from about 0.015 g/cm.sup.3 to about 0.20 g/cm.sup.3 and a pore size of from about 0.01 microns to about 1.0 micron within the open cells of said first foam.

  1. Efficient Representation of Detailed Foam Waves by Incorporating Projective Space.

    PubMed

    Kim, Jong-Hyun; Lee, Jung; Cha, Sungdeok; Kim, Chang-Hun

    2016-09-14

    We propose an efficient framework to realistically simulate foam effects in which 3D water particles from a base water solver are first projected onto 2D screen space in order to reduce computational complexity of finding foam particles. Because foam effects are often created primarily in fast and complicated water flows, we analyze acceleration and curvature values to identify the areas exhibiting such flow patterns. Identified foam particles are emitted in 3D simulation space, and each foam particle is advected by its classified type based on its velocity, thereby capturing the essential characteristics of foam wave motions (e.g., floating waves or scattering bubbles). In addition, we provide an intuitive and flexible mechanism (e.g., user sketch or image) to customize parameters and control the appearance of foam effects while minimizing the occurrence of popping artifacts. Experiments convincingly demonstrate that the proposed approach is efficient and easy to use while delivering high-quality results.

  2. The defect level and ideal thermal conductivity of graphene uncovered by residual thermal reffusivity at the 0 K limit.

    PubMed

    Xie, Yangsu; Xu, Zaoli; Xu, Shen; Cheng, Zhe; Hashemi, Nastaran; Deng, Cheng; Wang, Xinwei

    2015-06-14

    Due to its intriguing thermal and electrical properties, graphene has been widely studied for potential applications in sensor and energy devices. However, the reported value for its thermal conductivity spans from dozens to thousands of W m(-1) K(-1) due to different levels of alternations and defects in graphene samples. In this work, the thermal diffusivity of suspended four-layered graphene foam (GF) is characterized from room temperature (RT) down to 17 K. For the first time, we identify the defect level in graphene by evaluating the inverse of thermal diffusivity (termed "thermal reffusivity": Θ) at the 0 K limit. By using the Debye model of Θ = Θ0 + C× e(-θ/2T) and fitting the Θ-T curve to the point of T = 0 K, we identify the defect level (Θ0) and determine the Debye temperature of graphene. Θ0 is found to be 1878 s m(-2) for the studied GF and 43-112 s m(-2) for three highly crystalline graphite materials. This uncovers a 16-43-fold higher defect level in GF than that in pyrolytic graphite. In GF, the phonon mean free path solely induced by defects and boundary scattering is determined as 166 nm. The Debye temperature of graphene is determined to be 1813 K, which is very close to the average theoretical Debye temperature (1911 K) of the three acoustic phonon modes in graphene. By subtracting the defect effect, we report the ideal thermal diffusivity and conductivity (κideal) of graphene presented in the 3D foam structure in the range of 33-299 K. Detailed physics based on chemical composition and structure analysis are given to explain the κideal-T profile by comparing with those reported for suspended graphene.

  3. Intraoral 3D scanner

    NASA Astrophysics Data System (ADS)

    Kühmstedt, Peter; Bräuer-Burchardt, Christian; Munkelt, Christoph; Heinze, Matthias; Palme, Martin; Schmidt, Ingo; Hintersehr, Josef; Notni, Gunther

    2007-09-01

    Here a new set-up of a 3D-scanning system for CAD/CAM in dental industry is proposed. The system is designed for direct scanning of the dental preparations within the mouth. The measuring process is based on phase correlation technique in combination with fast fringe projection in a stereo arrangement. The novelty in the approach is characterized by the following features: A phase correlation between the phase values of the images of two cameras is used for the co-ordinate calculation. This works contrary to the usage of only phase values (phasogrammetry) or classical triangulation (phase values and camera image co-ordinate values) for the determination of the co-ordinates. The main advantage of the method is that the absolute value of the phase at each point does not directly determine the coordinate. Thus errors in the determination of the co-ordinates are prevented. Furthermore, using the epipolar geometry of the stereo-like arrangement the phase unwrapping problem of fringe analysis can be solved. The endoscope like measurement system contains one projection and two camera channels for illumination and observation of the object, respectively. The new system has a measurement field of nearly 25mm × 15mm. The user can measure two or three teeth at one time. So the system can by used for scanning of single tooth up to bridges preparations. In the paper the first realization of the intraoral scanner is described.

  4. 'Diamond' in 3-D

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This 3-D, microscopic imager mosaic of a target area on a rock called 'Diamond Jenness' was taken after NASA's Mars Exploration Rover Opportunity ground into the surface with its rock abrasion tool for a second time.

    Opportunity has bored nearly a dozen holes into the inner walls of 'Endurance Crater.' On sols 177 and 178 (July 23 and July 24, 2004), the rover worked double-duty on Diamond Jenness. Surface debris and the bumpy shape of the rock resulted in a shallow and irregular hole, only about 2 millimeters (0.08 inch) deep. The final depth was not enough to remove all the bumps and leave a neat hole with a smooth floor. This extremely shallow depression was then examined by the rover's alpha particle X-ray spectrometer.

    On Sol 178, Opportunity's 'robotic rodent' dined on Diamond Jenness once again, grinding almost an additional 5 millimeters (about 0.2 inch). The rover then applied its Moessbauer spectrometer to the deepened hole. This double dose of Diamond Jenness enabled the science team to examine the rock at varying layers. Results from those grindings are currently being analyzed.

    The image mosaic is about 6 centimeters (2.4 inches) across.

  5. Prominent rocks - 3D

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Many prominent rocks near the Sagan Memorial Station are featured in this image, taken in stereo by the Imager for Mars Pathfinder (IMP) on Sol 3. 3D glasses are necessary to identify surface detail. Wedge is at lower left; Shark, Half-Dome, and Pumpkin are at center. Flat Top, about four inches high, is at lower right. The horizon in the distance is one to two kilometers away.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

    Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right

  6. Highly oriented graphene growth and characterization

    NASA Astrophysics Data System (ADS)

    Saheed, Mohamed Salleh Mohamed; Mohamed, Norani Muti; Singh, Balbir Singh Mahinder; Saheed, Mohamed Shuaib Mohamed

    2016-11-01

    Combination of the highly ordered monolayers to form the multilayer interconnected graphene is essential to produce robust and free standing graphene unlike its counterpart 2D monolayers. Here, chemical vapor deposition (CVD) technique is employed to produce highly flexible and high mobility 3D graphene. In this study, the 3D graphene is grown via direct carbon deposition on sacrificial template. With the use of polymer coating such as poly methyl methacrylate (PMMA), it is observed that the graphene is bendable without any degradation. Great potential in term of electrical conductivity and flexibility can be exploited for future work for this CVD grown 3D graphene.

  7. Forming foam structures with carbon foam substrates

    DOEpatents

    Landingham, Richard L.; Satcher, Jr., Joe H.; Coronado, Paul R.; Baumann, Theodore F.

    2012-11-06

    The invention provides foams of desired cell sizes formed from metal or ceramic materials that coat the surfaces of carbon foams which are subsequently removed. For example, metal is located over a sol-gel foam monolith. The metal is melted to produce a metal/sol-gel composition. The sol-gel foam monolith is removed, leaving a metal foam.

  8. Foam patterns

    DOEpatents

    Chaudhry, Anil R; Dzugan, Robert; Harrington, Richard M; Neece, Faurice D; Singh, Nipendra P; Westendorf, Travis

    2013-11-26

    A method of creating a foam pattern comprises mixing a polyol component and an isocyanate component to form a liquid mixture. The method further comprises placing a temporary core having a shape corresponding to a desired internal feature in a cavity of a mold and inserting the mixture into the cavity of the mold so that the mixture surrounds a portion of the temporary core. The method optionally further comprises using supporting pins made of foam to support the core in the mold cavity, with such pins becoming integral part of the pattern material simplifying subsequent processing. The method further comprises waiting for a predetermined time sufficient for a reaction from the mixture to form a foam pattern structure corresponding to the cavity of the mold, wherein the foam pattern structure encloses a portion of the temporary core and removing the temporary core from the pattern independent of chemical leaching.

  9. Synthesis of reduced graphene oxide intercalated ZnO quantum dots nanoballs for selective biosensing detection

    NASA Astrophysics Data System (ADS)

    Chen, Jing; Zhao, Minggang; Li, Yingchun; Fan, Sisi; Ding, Longjiang; Liang, Jingjing; Chen, Shougang

    2016-07-01

    ZnO quantum dots (QDs), reduced graphene oxide (rGO) and multi-walled carbon nanotubes (MWCNTs) are always used in sensors due to their excellent electrochemical characteristics. In this work, ZnO QDs were intercalated by rGO sheets with cross-linked MWCNTs to construct intercalation nanoballs. A MWCNTs/rGO/ZnO QDs 3D hierarchical architecture was fabricated on supporting Ni foam, which exhibited excellent mechanical, kinetic and electrochemical properties. The intercalation construction can introduce strong interfacial effects to improve the surface electronic state. The selectively determinate of uric acid, dopamine, and ascorbic acid by an electrode material using distinct applied potentials was realized.

  10. 3-D graphene-supported mesoporous SiO2 @Fe3 O4 composites for the analysis of pesticides in aqueous samples by magnetic solid-phase extraction with high-performance liquid chromatography.

    PubMed

    Wang, Xuemei; Wang, Huan; Lu, Muxin; Ma, Xiaomin; Huang, Pengfei; Lu, Xiaoquan; Du, Xinzhen

    2016-05-01

    Three-dimensional graphene-supported mesoporous silica@Fe3 O4 composites (mSiO2 @Fe3 O4 -G) were prepared by modifying mesoporous SiO2 -coated Fe3 O4 onto hydrophobic graphene nanosheets through a simple adsorption co-condensation method. The obtained composites possess unique properties of large surface area (332.9 m(2) /g), pore volume (0.68 cm(3) /g), highly open pore structure with uniform pore size (31.1 nm), as well as good magnetic separation properties. The adsorbent (mSiO2 @Fe3 O4 -G) was used for the magnetic solid-phase extraction of seven pesticides with benzene rings in different aqueous samples before high-performance liquid chromatography. The main parameters affecting the extraction such as adsorbent amount, volume of elution solvent, time of extraction and desorption, salt effect, oscillation rate were investigated. Under the optimal conditions, this method provided low limits of detection (S/N = 3, 0.525-3.30 μg/L) and good linearity (5.0-1000 μg/L, R(2) > 0.9954). Method validation proved the feasibility of the developed adsorbent, which has a high extraction efficiency and excellent enhancement performance for pesticides in this study. The proposed method was successfully applied to real aqueous samples, and satisfactory recoveries ranging from 77.5 to 113.6% with relative standard deviations within 9.7% were obtained.

  11. Temper Foam

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Fabricated by Expanded Rubber & Plastics Corporation, Temper Foam provides better impact protection for airplane passengers and enhances passenger comfort on long flights because it distributes body weight and pressure evenly over the entire contact area. Called a "memory foam" it matches the contour of the body pressing against it and returns to its original shape once the pressure is removed. As a shock absorber, a three-inch foam pad has the ability to absorb the impact of a 10-foot fall by an adult. Applications include seat cushioning for transportation vehicles, padding for furniture and a variety of athletic equipment medical applications including wheelchair padding, artificial limb socket lining, finger splint and hand padding for burn patients, special mattresses for the bedridden and dental stools. Production and sales rights are owned by Temper Foam, Inc. Material is manufactured under license by the Dewey and Almy Division of Grace Chemical Corporation. Distributors of the product are Kees Goebel Medical Specialties, Inc. and Alimed, Inc. They sell Temper Foam in bulk to the fabricators who trim it to shapes required by their customers.

  12. Foam drainage

    SciTech Connect

    Kraynik, A.M.

    1983-11-01

    Transient drainage from a column of persistent foam has been analyzed theoretically. Gravity-driven flow was assumed to occur through an interconnected network of Plateau borders that define the edges of foam cells taken to be regular pentagonal dodecahedrons. A small liquid volume fraction and monodisperse cell size distribution were assumed. In the basic model, it is assumed that all liquid is contained in Plateau borders that are bounded by rigid gas-liquid interfaces. The predicted half life, the time required for one half of the liquid to drain from the foam, is inversely proportional to the square of the cell diameter, illustrating the importance of foam structure in drainage. Liquid hold up in the films separating adjacent cells, nonuniform initial liquid volume fraction distribution and interfacial mobility are explored. Border suction due to reduced pressure in the Plateau borders provides a mechanism for film drainage. Simultaneous film drainage and flow through the Plateau borders are analyzed. Sufficient conditions for neglecting film drainage kinetics are obtained. The results indicate that improved foam stability is related to small cells, liquid hold up in the films and slow film drainage kinetics.

  13. 3D Spectroscopy in Astronomy

    NASA Astrophysics Data System (ADS)

    Mediavilla, Evencio; Arribas, Santiago; Roth, Martin; Cepa-Nogué, Jordi; Sánchez, Francisco

    2011-09-01

    Preface; Acknowledgements; 1. Introductory review and technical approaches Martin M. Roth; 2. Observational procedures and data reduction James E. H. Turner; 3. 3D Spectroscopy instrumentation M. A. Bershady; 4. Analysis of 3D data Pierre Ferruit; 5. Science motivation for IFS and galactic studies F. Eisenhauer; 6. Extragalactic studies and future IFS science Luis Colina; 7. Tutorials: how to handle 3D spectroscopy data Sebastian F. Sánchez, Begona García-Lorenzo and Arlette Pécontal-Rousset.

  14. Spherical 3D isotropic wavelets

    NASA Astrophysics Data System (ADS)

    Lanusse, F.; Rassat, A.; Starck, J.-L.

    2012-04-01

    Context. Future cosmological surveys will provide 3D large scale structure maps with large sky coverage, for which a 3D spherical Fourier-Bessel (SFB) analysis in spherical coordinates is natural. Wavelets are particularly well-suited to the analysis and denoising of cosmological data, but a spherical 3D isotropic wavelet transform does not currently exist to analyse spherical 3D data. Aims: The aim of this paper is to present a new formalism for a spherical 3D isotropic wavelet, i.e. one based on the SFB decomposition of a 3D field and accompany the formalism with a public code to perform wavelet transforms. Methods: We describe a new 3D isotropic spherical wavelet decomposition based on the undecimated wavelet transform (UWT) described in Starck et al. (2006). We also present a new fast discrete spherical Fourier-Bessel transform (DSFBT) based on both a discrete Bessel transform and the HEALPIX angular pixelisation scheme. We test the 3D wavelet transform and as a toy-application, apply a denoising algorithm in wavelet space to the Virgo large box cosmological simulations and find we can successfully remove noise without much loss to the large scale structure. Results: We have described a new spherical 3D isotropic wavelet transform, ideally suited to analyse and denoise future 3D spherical cosmological surveys, which uses a novel DSFBT. We illustrate its potential use for denoising using a toy model. All the algorithms presented in this paper are available for download as a public code called MRS3D at http://jstarck.free.fr/mrs3d.html

  15. 3D Elevation Program—Virtual USA in 3D

    USGS Publications Warehouse

    Lukas, Vicki; Stoker, J.M.

    2016-04-14

    The U.S. Geological Survey (USGS) 3D Elevation Program (3DEP) uses a laser system called ‘lidar’ (light detection and ranging) to create a virtual reality map of the Nation that is very accurate. 3D maps have many uses with new uses being discovered all the time.  

  16. Proof-of-Concept: Assembling Carbon Nanocrystals for Ordered 3D Network

    DTIC Science & Technology

    2011-12-13

    for 3D ordering carbon nanotube networks. In this project, a ultra-thin poly( methyl methacrylate ) (PMMA) was coated to ~50nm graphene film. At the...mechanical performance. Subsequently, the filtered graphene film was immersed into acetone to etch the filter membrane, and the resultant freestanding

  17. Graphene based polyurethane material: As highly pressure sensitive composite

    NASA Astrophysics Data System (ADS)

    Hodlur, R. M.; Rabinal, M. K.

    2012-06-01

    In our present work, we describe a simple method for uniform coating of Graphite oxide (GO) onto flexible polyurethane (PU) foams. These PU foams loaded with GO were made electrically conducting by converting insulating GO to conducting graphene by chemical reduction process without damaging the foam properties. These PU foams loaded with graphene were characterized by SEM and TGA. The morphology, thermal properties and pressure dependent electrical conductivity of these foams was studied. The electric current increased by five orders of magnitude due to applied pressure.

  18. System and method for 3D printing of aerogels

    DOEpatents

    Worsley, Marcus A.; Duoss, Eric; Kuntz, Joshua; Spadaccini, Christopher; Zhu, Cheng

    2016-03-08

    A method of forming an aerogel. The method may involve providing a graphene oxide powder and mixing the graphene oxide powder with a solution to form an ink. A 3D printing technique may be used to write the ink into a catalytic solution that is contained in a fluid containment member to form a wet part. The wet part may then be cured in a sealed container for a predetermined period of time at a predetermined temperature. The cured wet part may then be dried to form a finished aerogel part.

  19. 3D World Building System

    ScienceCinema

    None

    2016-07-12

    This video provides an overview of the Sandia National Laboratories developed 3-D World Model Building capability that provides users with an immersive, texture rich 3-D model of their environment in minutes using a laptop and color and depth camera.

  20. 3D Buckligami: Digital Matter

    NASA Astrophysics Data System (ADS)

    van Hecke, Martin; de Reus, Koen; Florijn, Bastiaan; Coulais, Corentin

    2014-03-01

    We present a class of elastic structures which exhibit collective buckling in 3D, and create these by a 3D printing/moulding technique. Our structures consist of cubic lattice of anisotropic unit cells, and we show that their mechanical properties are programmable via the orientation of these unit cells.

  1. 3D World Building System

    SciTech Connect

    2013-10-30

    This video provides an overview of the Sandia National Laboratories developed 3-D World Model Building capability that provides users with an immersive, texture rich 3-D model of their environment in minutes using a laptop and color and depth camera.

  2. LLNL-Earth3D

    SciTech Connect

    2013-10-01

    Earth3D is a computer code designed to allow fast calculation of seismic rays and travel times through a 3D model of the Earth. LLNL is using this for earthquake location and global tomography efforts and such codes are of great interest to the Earth Science community.

  3. Market study: 3-D eyetracker

    NASA Technical Reports Server (NTRS)

    1977-01-01

    A market study of a proposed version of a 3-D eyetracker for initial use at NASA's Ames Research Center was made. The commercialization potential of a simplified, less expensive 3-D eyetracker was ascertained. Primary focus on present and potential users of eyetrackers, as well as present and potential manufacturers has provided an effective means of analyzing the prospects for commercialization.

  4. Euro3D Science Conference

    NASA Astrophysics Data System (ADS)

    Walsh, J. R.

    2004-02-01

    The Euro3D RTN is an EU funded Research Training Network to foster the exploitation of 3D spectroscopy in Europe. 3D spectroscopy is a general term for spectroscopy of an area of the sky and derives its name from its two spatial + one spectral dimensions. There are an increasing number of instruments which use integral field devices to achieve spectroscopy of an area of the sky, either using lens arrays, optical fibres or image slicers, to pack spectra of multiple pixels on the sky (``spaxels'') onto a 2D detector. On account of the large volume of data and the special methods required to reduce and analyse 3D data, there are only a few centres of expertise and these are mostly involved with instrument developments. There is a perceived lack of expertise in 3D spectroscopy spread though the astronomical community and its use in the armoury of the observational astronomer is viewed as being highly specialised. For precisely this reason the Euro3D RTN was proposed to train young researchers in this area and develop user tools to widen the experience with this particular type of data in Europe. The Euro3D RTN is coordinated by Martin M. Roth (Astrophysikalisches Institut Potsdam) and has been running since July 2002. The first Euro3D science conference was held in Cambridge, UK from 22 to 23 May 2003. The main emphasis of the conference was, in keeping with the RTN, to expose the work of the young post-docs who are funded by the RTN. In addition the team members from the eleven European institutes involved in Euro3D also presented instrumental and observational developments. The conference was organized by Andy Bunker and held at the Institute of Astronomy. There were over thirty participants and 26 talks covered the whole range of application of 3D techniques. The science ranged from Galactic planetary nebulae and globular clusters to kinematics of nearby galaxies out to objects at high redshift. Several talks were devoted to reporting recent observations with newly

  5. Graphene and Graphene Oxide: Biofunctionalization and Applications in Biotechnology

    SciTech Connect

    Wang, Ying; Li, Zhaohui; Wang, Jun; Li, Jinghong; Lin, Yuehe

    2011-05-01

    Graphene is the basic building block of zero-dimensional fullerene, 1D carbon nanotubes, and 3D graphite. Graphene has a unique planar structure as well as novel electronic properties, which have attracted great interest from scientists. This review selectively analyzes current advances in the field of graphene bioapplications. In particular, the functionalization of graphene for biological applications, FRET-based biosensor development by using graphene-based nanomaterials, and the investigation of graphene for living cell studies have been summarized in more details. Future perspectives and possible challenges in this rapidly developing area are also discussed.

  6. 3D vision system assessment

    NASA Astrophysics Data System (ADS)

    Pezzaniti, J. Larry; Edmondson, Richard; Vaden, Justin; Hyatt, Bryan; Chenault, David B.; Kingston, David; Geulen, Vanilynmae; Newell, Scott; Pettijohn, Brad

    2009-02-01

    In this paper, we report on the development of a 3D vision system consisting of a flat panel stereoscopic display and auto-converging stereo camera and an assessment of the system's use for robotic driving, manipulation, and surveillance operations. The 3D vision system was integrated onto a Talon Robot and Operator Control Unit (OCU) such that direct comparisons of the performance of a number of test subjects using 2D and 3D vision systems were possible. A number of representative scenarios were developed to determine which tasks benefited most from the added depth perception and to understand when the 3D vision system hindered understanding of the scene. Two tests were conducted at Fort Leonard Wood, MO with noncommissioned officers ranked Staff Sergeant and Sergeant First Class. The scenarios; the test planning, approach and protocols; the data analysis; and the resulting performance assessment of the 3D vision system are reported.

  7. 3D printing in dentistry.

    PubMed

    Dawood, A; Marti Marti, B; Sauret-Jackson, V; Darwood, A

    2015-12-01

    3D printing has been hailed as a disruptive technology which will change manufacturing. Used in aerospace, defence, art and design, 3D printing is becoming a subject of great interest in surgery. The technology has a particular resonance with dentistry, and with advances in 3D imaging and modelling technologies such as cone beam computed tomography and intraoral scanning, and with the relatively long history of the use of CAD CAM technologies in dentistry, it will become of increasing importance. Uses of 3D printing include the production of drill guides for dental implants, the production of physical models for prosthodontics, orthodontics and surgery, the manufacture of dental, craniomaxillofacial and orthopaedic implants, and the fabrication of copings and frameworks for implant and dental restorations. This paper reviews the types of 3D printing technologies available and their various applications in dentistry and in maxillofacial surgery.

  8. PLOT3D user's manual

    NASA Technical Reports Server (NTRS)

    Walatka, Pamela P.; Buning, Pieter G.; Pierce, Larry; Elson, Patricia A.

    1990-01-01

    PLOT3D is a computer graphics program designed to visualize the grids and solutions of computational fluid dynamics. Seventy-four functions are available. Versions are available for many systems. PLOT3D can handle multiple grids with a million or more grid points, and can produce varieties of model renderings, such as wireframe or flat shaded. Output from PLOT3D can be used in animation programs. The first part of this manual is a tutorial that takes the reader, keystroke by keystroke, through a PLOT3D session. The second part of the manual contains reference chapters, including the helpfile, data file formats, advice on changing PLOT3D, and sample command files.

  9. PLOT3D/AMES, APOLLO UNIX VERSION USING GMR3D (WITHOUT TURB3D)

    NASA Technical Reports Server (NTRS)

    Buning, P.

    1994-01-01

    PLOT3D is an interactive graphics program designed to help scientists visualize computational fluid dynamics (CFD) grids and solutions. Today, supercomputers and CFD algorithms can provide scientists with simulations of such highly complex phenomena that obtaining an understanding of the simulations has become a major problem. Tools which help the scientist visualize the simulations can be of tremendous aid. PLOT3D/AMES offers more functions and features, and has been adapted for more types of computers than any other CFD graphics program. Version 3.6b+ is supported for five computers and graphic libraries. Using PLOT3D, CFD physicists can view their computational models from any angle, observing the physics of problems and the quality of solutions. As an aid in designing aircraft, for example, PLOT3D's interactive computer graphics can show vortices, temperature, reverse flow, pressure, and dozens of other characteristics of air flow during flight. As critical areas become obvious, they can easily be studied more closely using a finer grid. PLOT3D is part of a computational fluid dynamics software cycle. First, a program such as 3DGRAPE (ARC-12620) helps the scientist generate computational grids to model an object and its surrounding space. Once the grids have been designed and parameters such as the angle of attack, Mach number, and Reynolds number have been specified, a "flow-solver" program such as INS3D (ARC-11794 or COS-10019) solves the system of equations governing fluid flow, usually on a supercomputer. Grids sometimes have as many as two million points, and the "flow-solver" produces a solution file which contains density, x- y- and z-momentum, and stagnation energy for each grid point. With such a solution file and a grid file containing up to 50 grids as input, PLOT3D can calculate and graphically display any one of 74 functions, including shock waves, surface pressure, velocity vectors, and particle traces. PLOT3D's 74 functions are organized into

  10. PLOT3D/AMES, APOLLO UNIX VERSION USING GMR3D (WITH TURB3D)

    NASA Technical Reports Server (NTRS)

    Buning, P.

    1994-01-01

    PLOT3D is an interactive graphics program designed to help scientists visualize computational fluid dynamics (CFD) grids and solutions. Today, supercomputers and CFD algorithms can provide scientists with simulations of such highly complex phenomena that obtaining an understanding of the simulations has become a major problem. Tools which help the scientist visualize the simulations can be of tremendous aid. PLOT3D/AMES offers more functions and features, and has been adapted for more types of computers than any other CFD graphics program. Version 3.6b+ is supported for five computers and graphic libraries. Using PLOT3D, CFD physicists can view their computational models from any angle, observing the physics of problems and the quality of solutions. As an aid in designing aircraft, for example, PLOT3D's interactive computer graphics can show vortices, temperature, reverse flow, pressure, and dozens of other characteristics of air flow during flight. As critical areas become obvious, they can easily be studied more closely using a finer grid. PLOT3D is part of a computational fluid dynamics software cycle. First, a program such as 3DGRAPE (ARC-12620) helps the scientist generate computational grids to model an object and its surrounding space. Once the grids have been designed and parameters such as the angle of attack, Mach number, and Reynolds number have been specified, a "flow-solver" program such as INS3D (ARC-11794 or COS-10019) solves the system of equations governing fluid flow, usually on a supercomputer. Grids sometimes have as many as two million points, and the "flow-solver" produces a solution file which contains density, x- y- and z-momentum, and stagnation energy for each grid point. With such a solution file and a grid file containing up to 50 grids as input, PLOT3D can calculate and graphically display any one of 74 functions, including shock waves, surface pressure, velocity vectors, and particle traces. PLOT3D's 74 functions are organized into

  11. Foam flotation

    SciTech Connect

    Clarke, A.N.; Wilson, D.J.

    1983-01-01

    This book is a review of precipitate and absorbing colloid flotation and mathemataical analyses of physical models regarding foam flotation phenomena. Over 800 literature references are cited. Contents include some fluid mechanical aspects of particle flotation, theoretical aspects of particulate flotation, column design considerations, solvent sublation, the future and appendices.

  12. Polyimide foams

    NASA Technical Reports Server (NTRS)

    Vazquez, Juan M. (Inventor); Cano, Roberto J. (Inventor); Jensen, Brian J. (Inventor); Weiser, Erik S. (Inventor)

    2009-01-01

    A fully imidized, solvent-free polyimide foam having excellent mechanical, acoustic, thermal, and flame resistant properties is produced. A first solution is provided, which includes one or more aromatic dianhydrides or derivatives of aromatic dianhydrides, and may include one or more aromatic diamines, dissolved in one or more polar solvents, along with an effective amount of one or more blowing agents. This first solution may also advantageously include effective amounts respectively of one or mores catalysts, one or more surfactants, and one or more fire retardants. A second solution is also provided which includes one or more isocyanates. The first and second solutions are rapidly and thoroughly mixed to produce an admixture, which is allowed to foam--in an open container, or in a closed mold--under ambient conditions to completion produce a foamed product. This foamed product is then cured by high frequency electromagnetic radiation, thermal energy, or a combination thereof. Alternatively, the process is adapted for spraying or extrusion.

  13. Polyimide foams

    NASA Technical Reports Server (NTRS)

    Vazquez, Juan M. (Inventor); Cano, Roberto J. (Inventor); Jensen, Brian J. (Inventor); Weiser, Erik S. (Inventor)

    2005-01-01

    A fully imidized, solvent-free polyimide foam having excellent mechanical, acoustic, thermal, and flame resistant properties is produced. A first solution is provided, which includes one or more aromatic dianhydrides or derivatives of aromatic dianhydrides, and may include one or more aromatic diamines, dissolved in one or more polar solvents, along with an effective amount of one or more blowing agents. This first solution may also advantageously include effective amounts respectively of one or mores catalysts, one or more surfactants, and one or more fire retardants. A second solution is also provided which includes one or more isocyanates. The first and second solutions are rapidly and thoroughly mixed to produce an admixture, which is allowed to foam?in an open container, or in a closed mold?under ambient conditions to completion produce a foamed product. This foamed product is then cured by high frequency electromagnetic radiation, thermal energy, or a combination thereof. Alternatively, the process is adapted for spraying or extrusion.

  14. Unassisted 3D camera calibration

    NASA Astrophysics Data System (ADS)

    Atanassov, Kalin; Ramachandra, Vikas; Nash, James; Goma, Sergio R.

    2012-03-01

    With the rapid growth of 3D technology, 3D image capture has become a critical part of the 3D feature set on mobile phones. 3D image quality is affected by the scene geometry as well as on-the-device processing. An automatic 3D system usually assumes known camera poses accomplished by factory calibration using a special chart. In real life settings, pose parameters estimated by factory calibration can be negatively impacted by movements of the lens barrel due to shaking, focusing, or camera drop. If any of these factors displaces the optical axes of either or both cameras, vertical disparity might exceed the maximum tolerable margin and the 3D user may experience eye strain or headaches. To make 3D capture more practical, one needs to consider unassisted (on arbitrary scenes) calibration. In this paper, we propose an algorithm that relies on detection and matching of keypoints between left and right images. Frames containing erroneous matches, along with frames with insufficiently rich keypoint constellations, are detected and discarded. Roll, pitch yaw , and scale differences between left and right frames are then estimated. The algorithm performance is evaluated in terms of the remaining vertical disparity as compared to the maximum tolerable vertical disparity.

  15. 3D Scan Systems Integration

    DTIC Science & Technology

    2007-11-02

    AGENCY USE ONLY (Leave Blank) 2. REPORT DATE 5 Feb 98 4. TITLE AND SUBTITLE 3D Scan Systems Integration REPORT TYPE AND DATES COVERED...2-89) Prescribed by ANSI Std. Z39-1 298-102 [ EDO QUALITY W3PECTEDI DLA-ARN Final Report for US Defense Logistics Agency on DDFG-T2/P3: 3D...SCAN SYSTEMS INTEGRATION Contract Number SPO100-95-D-1014 Contractor Ohio University Delivery Order # 0001 Delivery Order Title 3D Scan Systems

  16. 3D polymer scaffold arrays.

    PubMed

    Simon, Carl G; Yang, Yanyin; Dorsey, Shauna M; Ramalingam, Murugan; Chatterjee, Kaushik

    2011-01-01

    We have developed a combinatorial platform for fabricating tissue scaffold arrays that can be used for screening cell-material interactions. Traditional research involves preparing samples one at a time for characterization and testing. Combinatorial and high-throughput (CHT) methods lower the cost of research by reducing the amount of time and material required for experiments by combining many samples into miniaturized specimens. In order to help accelerate biomaterials research, many new CHT methods have been developed for screening cell-material interactions where materials are presented to cells as a 2D film or surface. However, biomaterials are frequently used to fabricate 3D scaffolds, cells exist in vivo in a 3D environment and cells cultured in a 3D environment in vitro typically behave more physiologically than those cultured on a 2D surface. Thus, we have developed a platform for fabricating tissue scaffold libraries where biomaterials can be presented to cells in a 3D format.

  17. Autofocus for 3D imaging

    NASA Astrophysics Data System (ADS)

    Lee-Elkin, Forest

    2008-04-01

    Three dimensional (3D) autofocus remains a significant challenge for the development of practical 3D multipass radar imaging. The current 2D radar autofocus methods are not readily extendable across sensor passes. We propose a general framework that allows a class of data adaptive solutions for 3D auto-focus across passes with minimal constraints on the scene contents. The key enabling assumption is that portions of the scene are sparse in elevation which reduces the number of free variables and results in a system that is simultaneously solved for scatterer heights and autofocus parameters. The proposed method extends 2-pass interferometric synthetic aperture radar (IFSAR) methods to an arbitrary number of passes allowing the consideration of scattering from multiple height locations. A specific case from the proposed autofocus framework is solved and demonstrates autofocus and coherent multipass 3D estimation across the 8 passes of the "Gotcha Volumetric SAR Data Set" X-Band radar data.

  18. Combinatorial 3D Mechanical Metamaterials

    NASA Astrophysics Data System (ADS)

    Coulais, Corentin; Teomy, Eial; de Reus, Koen; Shokef, Yair; van Hecke, Martin

    2015-03-01

    We present a class of elastic structures which exhibit 3D-folding motion. Our structures consist of cubic lattices of anisotropic unit cells that can be tiled in a complex combinatorial fashion. We design and 3d-print this complex ordered mechanism, in which we combine elastic hinges and defects to tailor the mechanics of the material. Finally, we use this large design space to encode smart functionalities such as surface patterning and multistability.

  19. Facile synthesis of porous graphene as binder-free electrode for supercapacitor application

    NASA Astrophysics Data System (ADS)

    Luo, Guangsheng; Huang, Haifu; Lei, Chenglong; Cheng, Zhenzhi; Wu, Xiaoshan; Tang, Shaolong; Du, Youwei

    2016-03-01

    Here, porous grapheme oxide (GO) gel deposited on nickel foam was prepared by using polystyrene (PS) colloidal particles as spacers for use as electrodes in high rate supercapacitors, then reduced by Vitamin C aqueous solution in ambient condition. The PS particles were surrounded by reduced graphene oxide (rGO) sheets, forming crinkles and rough textures. When PS particles were selectively removed, rGO gel coated on the skeleton of Ni foam can formed an open porous structure, which prevents elf-aggregation and restacking of graphene sheets. The porous rGO-based supercapacitors exhibit excellent electrochemical performances such as a specific capacitance of 152 F g-1 at 1 A g-1, high rate capability of 53% capacitance retention upon a current increase to 100 A g-1 and good cycle stability, due to effective rapid and short pathways for ionic and electronic transport provided by the sub-micrometer structure of rGO gel and 3D interconnected network of Ni foam.

  20. Single-layer graphene-assembled 3D porous carbon composites with PVA and Fe₃O₄ nano-fillers: an interface-mediated superior dielectric and EMI shielding performance.

    PubMed

    Rao, B V Bhaskara; Yadav, Prasad; Aepuru, Radhamanohar; Panda, H S; Ogale, Satishchandra; Kale, S N

    2015-07-28

    In this study, a novel composite of Fe3O4 nanofiller-decorated single-layer graphene-assembled porous carbon (SLGAPC) with polyvinyl alcohol (PVA) having flexibility and a density of 0.75 g cm(-3) is explored for its dielectric and electromagnetic interference (EMI) response properties. The composite is prepared by the solution casting method and its constituents are optimized as 15 wt% SLGAPC and 20 wt% Fe3O4 through a novel solvent relaxation nuclear magnetic resonance experiment. The PVA-SLGAPC-Fe3O4 composite shows high dielectric permittivity in the range of 1 Hz-10 MHz, enhanced by a factor of 4 as compared to that of the PVA-SLGAPC composite, with a reduced loss by a factor of 2. The temperature dependent dielectric properties reveal the activation energy behaviour with reference to the glass transition temperature (80 °C) of PVA. The dielectric hysteresis with the temperature cycle reveals a remnant polarization. The enhanced dielectric properties are suggested to be the result of improvement in the localized polarization of the integrated interface system (Maxwell-Wagner-Sillars (MWS) polarization) formed by the uniform adsorption of Fe3O4 on the surface of SLGAPC conjugated with PVA. The EMI shielding property of the composite with a low thickness of 0.3 mm in the X-band (8.2-12.4 GHz) shows a very impressive shielding efficiency of ∼15 dB and a specific shielding effectiveness of 20 dB (g cm(-3))(-1), indicating the promising character of this material for flexible EMI shielding applications.

  1. Foam Cushioning

    NASA Technical Reports Server (NTRS)

    1988-01-01

    One innovation developed by a contractor at Ames Research Center was an open cell polymeric foam material with unusual properties. Intended as padding for aircraft seats the material offered better impact protection against accidents, and also enhanced passenger comfort because it distributed body weight evenly over the entire contact area. Called a slow springback foam, it flows to match the contour of the body pressing against it, and returns to its original shape once the pressure is removed. It has many applications including aircraft cushions and padding, dental stools, and athletic equipment. Now it's used by Dynamic Systems, Inc. for medical applications such as wheel chairs for severely disabled people which allow them to sit for 3-8 hours where they used to be uncomfortable in 15-30 minutes.

  2. Infiltrated carbon foam composites

    NASA Technical Reports Server (NTRS)

    Lucas, Rick D. (Inventor); Danford, Harry E. (Inventor); Plucinski, Janusz W. (Inventor); Merriman, Douglas J. (Inventor); Blacker, Jesse M. (Inventor)

    2012-01-01

    An infiltrated carbon foam composite and method for making the composite is described. The infiltrated carbon foam composite may include a carbonized carbon aerogel in cells of a carbon foam body and a resin is infiltrated into the carbon foam body filling the cells of the carbon foam body and spaces around the carbonized carbon aerogel. The infiltrated carbon foam composites may be useful for mid-density ablative thermal protection systems.

  3. From 3D view to 3D print

    NASA Astrophysics Data System (ADS)

    Dima, M.; Farisato, G.; Bergomi, M.; Viotto, V.; Magrin, D.; Greggio, D.; Farinato, J.; Marafatto, L.; Ragazzoni, R.; Piazza, D.

    2014-08-01

    In the last few years 3D printing is getting more and more popular and used in many fields going from manufacturing to industrial design, architecture, medical support and aerospace. 3D printing is an evolution of bi-dimensional printing, which allows to obtain a solid object from a 3D model, realized with a 3D modelling software. The final product is obtained using an additive process, in which successive layers of material are laid down one over the other. A 3D printer allows to realize, in a simple way, very complex shapes, which would be quite difficult to be produced with dedicated conventional facilities. Thanks to the fact that the 3D printing is obtained superposing one layer to the others, it doesn't need any particular work flow and it is sufficient to simply draw the model and send it to print. Many different kinds of 3D printers exist based on the technology and material used for layer deposition. A common material used by the toner is ABS plastics, which is a light and rigid thermoplastic polymer, whose peculiar mechanical properties make it diffusely used in several fields, like pipes production and cars interiors manufacturing. I used this technology to create a 1:1 scale model of the telescope which is the hardware core of the space small mission CHEOPS (CHaracterising ExOPlanets Satellite) by ESA, which aims to characterize EXOplanets via transits observations. The telescope has a Ritchey-Chrétien configuration with a 30cm aperture and the launch is foreseen in 2017. In this paper, I present the different phases for the realization of such a model, focusing onto pros and cons of this kind of technology. For example, because of the finite printable volume (10×10×12 inches in the x, y and z directions respectively), it has been necessary to split the largest parts of the instrument in smaller components to be then reassembled and post-processed. A further issue is the resolution of the printed material, which is expressed in terms of layers

  4. YouDash3D: exploring stereoscopic 3D gaming for 3D movie theaters

    NASA Astrophysics Data System (ADS)

    Schild, Jonas; Seele, Sven; Masuch, Maic

    2012-03-01

    Along with the success of the digitally revived stereoscopic cinema, events beyond 3D movies become attractive for movie theater operators, i.e. interactive 3D games. In this paper, we present a case that explores possible challenges and solutions for interactive 3D games to be played by a movie theater audience. We analyze the setting and showcase current issues related to lighting and interaction. Our second focus is to provide gameplay mechanics that make special use of stereoscopy, especially depth-based game design. Based on these results, we present YouDash3D, a game prototype that explores public stereoscopic gameplay in a reduced kiosk setup. It features live 3D HD video stream of a professional stereo camera rig rendered in a real-time game scene. We use the effect to place the stereoscopic effigies of players into the digital game. The game showcases how stereoscopic vision can provide for a novel depth-based game mechanic. Projected trigger zones and distributed clusters of the audience video allow for easy adaptation to larger audiences and 3D movie theater gaming.

  5. Speaking Volumes About 3-D

    NASA Technical Reports Server (NTRS)

    2002-01-01

    In 1999, Genex submitted a proposal to Stennis Space Center for a volumetric 3-D display technique that would provide multiple users with a 360-degree perspective to simultaneously view and analyze 3-D data. The futuristic capabilities of the VolumeViewer(R) have offered tremendous benefits to commercial users in the fields of medicine and surgery, air traffic control, pilot training and education, computer-aided design/computer-aided manufacturing, and military/battlefield management. The technology has also helped NASA to better analyze and assess the various data collected by its satellite and spacecraft sensors. Genex capitalized on its success with Stennis by introducing two separate products to the commercial market that incorporate key elements of the 3-D display technology designed under an SBIR contract. The company Rainbow 3D(R) imaging camera is a novel, three-dimensional surface profile measurement system that can obtain a full-frame 3-D image in less than 1 second. The third product is the 360-degree OmniEye(R) video system. Ideal for intrusion detection, surveillance, and situation management, this unique camera system offers a continuous, panoramic view of a scene in real time.

  6. Macrophage podosomes go 3D.

    PubMed

    Van Goethem, Emeline; Guiet, Romain; Balor, Stéphanie; Charrière, Guillaume M; Poincloux, Renaud; Labrousse, Arnaud; Maridonneau-Parini, Isabelle; Le Cabec, Véronique

    2011-01-01

    Macrophage tissue infiltration is a critical step in the immune response against microorganisms and is also associated with disease progression in chronic inflammation and cancer. Macrophages are constitutively equipped with specialized structures called podosomes dedicated to extracellular matrix (ECM) degradation. We recently reported that these structures play a critical role in trans-matrix mesenchymal migration mode, a protease-dependent mechanism. Podosome molecular components and their ECM-degrading activity have been extensively studied in two dimensions (2D), but yet very little is known about their fate in three-dimensional (3D) environments. Therefore, localization of podosome markers and proteolytic activity were carefully examined in human macrophages performing mesenchymal migration. Using our gelled collagen I 3D matrix model to obligate human macrophages to perform mesenchymal migration, classical podosome markers including talin, paxillin, vinculin, gelsolin, cortactin were found to accumulate at the tip of F-actin-rich cell protrusions together with β1 integrin and CD44 but not β2 integrin. Macrophage proteolytic activity was observed at podosome-like protrusion sites using confocal fluorescence microscopy and electron microscopy. The formation of migration tunnels by macrophages inside the matrix was accomplished by degradation, engulfment and mechanic compaction of the matrix. In addition, videomicroscopy revealed that 3D F-actin-rich protrusions of migrating macrophages were as dynamic as their 2D counterparts. Overall, the specifications of 3D podosomes resembled those of 2D podosome rosettes rather than those of individual podosomes. This observation was further supported by the aspect of 3D podosomes in fibroblasts expressing Hck, a master regulator of podosome rosettes in macrophages. In conclusion, human macrophage podosomes go 3D and take the shape of spherical podosome rosettes when the cells perform mesenchymal migration. This work

  7. 3D Printed Bionic Nanodevices.

    PubMed

    Kong, Yong Lin; Gupta, Maneesh K; Johnson, Blake N; McAlpine, Michael C

    2016-06-01

    The ability to three-dimensionally interweave biological and functional materials could enable the creation of bionic devices possessing unique and compelling geometries, properties, and functionalities. Indeed, interfacing high performance active devices with biology could impact a variety of fields, including regenerative bioelectronic medicines, smart prosthetics, medical robotics, and human-machine interfaces. Biology, from the molecular scale of DNA and proteins, to the macroscopic scale of tissues and organs, is three-dimensional, often soft and stretchable, and temperature sensitive. This renders most biological platforms incompatible with the fabrication and materials processing methods that have been developed and optimized for functional electronics, which are typically planar, rigid and brittle. A number of strategies have been developed to overcome these dichotomies. One particularly novel approach is the use of extrusion-based multi-material 3D printing, which is an additive manufacturing technology that offers a freeform fabrication strategy. This approach addresses the dichotomies presented above by (1) using 3D printing and imaging for customized, hierarchical, and interwoven device architectures; (2) employing nanotechnology as an enabling route for introducing high performance materials, with the potential for exhibiting properties not found in the bulk; and (3) 3D printing a range of soft and nanoscale materials to enable the integration of a diverse palette of high quality functional nanomaterials with biology. Further, 3D printing is a multi-scale platform, allowing for the incorporation of functional nanoscale inks, the printing of microscale features, and ultimately the creation of macroscale devices. This blending of 3D printing, novel nanomaterial properties, and 'living' platforms may enable next-generation bionic systems. In this review, we highlight this synergistic integration of the unique properties of nanomaterials with the

  8. Petal, terrain & airbags - 3D

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Portions of the lander's deflated airbags and a petal are at the lower area of this image, taken in stereo by the Imager for Mars Pathfinder (IMP) on Sol 3. 3D glasses are necessary to identify surface detail. The metallic object at lower right is part of the lander's low-gain antenna. This image is part of a 3D 'monster

    Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right

  9. 3D Computations and Experiments

    SciTech Connect

    Couch, R; Faux, D; Goto, D; Nikkel, D

    2004-04-05

    This project consists of two activities. Task A, Simulations and Measurements, combines all the material model development and associated numerical work with the materials-oriented experimental activities. The goal of this effort is to provide an improved understanding of dynamic material properties and to provide accurate numerical representations of those properties for use in analysis codes. Task B, ALE3D Development, involves general development activities in the ALE3D code with the focus of improving simulation capabilities for problems of mutual interest to DoD and DOE. Emphasis is on problems involving multi-phase flow, blast loading of structures and system safety/vulnerability studies.

  10. Graphene Sandwiched Mesostructured Li-Ion Battery Electrodes.

    PubMed

    Liu, Jinyun; Zheng, Qiye; Goodman, Matthew D; Zhu, Haoyue; Kim, Jinwoo; Krueger, Neil A; Ning, Hailong; Huang, Xingjiu; Liu, Jinhuai; Terrones, Mauricio; Braun, Paul V

    2016-09-01

    A deterministic graphene-sandwiched Li-ion battery electrode consisting of an integrated 3D mesostructure of electrochemically active materials and graphene is presented. As demonstrations, electrodes with active nanomaterials that coat (V2 O5 @graphene@V2 O5 cathode) or are coated by (graphene@Si@graphene anode) graphene are fabricated. These electrodes exhibit high capacities and ultralong cycle lives (the cathode can be cycled over 2000 times with minimal capacity fade).

  11. Programmable hydrogenation of graphene for novel nanocages

    NASA Astrophysics Data System (ADS)

    Zhang, Liuyang; Zeng, Xiaowei; Wang, Xianqiao

    2013-11-01

    Folded graphene has exhibited novel electrical and mechanical properties unmatched by pristine graphene, which implies that morphology of graphene adds the dimensionality of design space to tailor its properties. However, how to overcome the energy barrier of the folding process to fold the graphene with the specific morphology remains unexplored. Here we propose a programmable chemical functionalization by doping a pristine graphene sheet in a certain pattern with hydrogen atoms to precisely control its folding morphology. Molecular dynamics simulation has been performed to create a cross-shaped cubic graphene nanocage encapsulating a biomolecule by warping the top graphene layer downward and the bottom graphene layer upward to mimic the drug delivery vehicle. Such a paradigm, programmable enabled graphene nanocage, opens up a new avenue to control the 3D architecture of folded graphene and therefore provides a feasible way to exploit and fabricate the graphene-based unconventional nanomaterials and nanodevices for drug delivery.

  12. The World of 3-D.

    ERIC Educational Resources Information Center

    Mayshark, Robin K.

    1991-01-01

    Students explore three-dimensional properties by creating red and green wall decorations related to Christmas. Students examine why images seem to vibrate when red and green pieces are small and close together. Instructions to conduct the activity and construct 3-D glasses are given. (MDH)

  13. 3D Printing: Exploring Capabilities

    ERIC Educational Resources Information Center

    Samuels, Kyle; Flowers, Jim

    2015-01-01

    As 3D printers become more affordable, schools are using them in increasing numbers. They fit well with the emphasis on product design in technology and engineering education, allowing students to create high-fidelity physical models to see and test different iterations in their product designs. They may also help students to "think in three…

  14. SNL3dFace

    SciTech Connect

    Russ, Trina; Koch, Mark; Koudelka, Melissa; Peters, Ralph; Little, Charles; Boehnen, Chris; Peters, Tanya

    2007-07-20

    This software distribution contains MATLAB and C++ code to enable identity verification using 3D images that may or may not contain a texture component. The code is organized to support system performance testing and system capability demonstration through the proper configuration of the available user interface. Using specific algorithm parameters the face recognition system has been demonstrated to achieve a 96.6% verification rate (Pd) at 0.001 false alarm rate. The system computes robust facial features of a 3D normalized face using Principal Component Analysis (PCA) and Fisher Linear Discriminant Analysis (FLDA). A 3D normalized face is obtained by alighning each face, represented by a set of XYZ coordinated, to a scaled reference face using the Iterative Closest Point (ICP) algorithm. The scaled reference face is then deformed to the input face using an iterative framework with parameters that control the deformed surface regulation an rate of deformation. A variety of options are available to control the information that is encoded by the PCA. Such options include the XYZ coordinates, the difference of each XYZ coordinates from the reference, the Z coordinate, the intensity/texture values, etc. In addition to PCA/FLDA feature projection this software supports feature matching to obtain similarity matrices for performance analysis. In addition, this software supports visualization of the STL, MRD, 2D normalized, and PCA synthetic representations in a 3D environment.

  15. Making Inexpensive 3-D Models

    ERIC Educational Resources Information Center

    Manos, Harry

    2016-01-01

    Visual aids are important to student learning, and they help make the teacher's job easier. Keeping with the "TPT" theme of "The Art, Craft, and Science of Physics Teaching," the purpose of this article is to show how teachers, lacking equipment and funds, can construct a durable 3-D model reference frame and a model gravity…

  16. Quantum Foam

    SciTech Connect

    Lincoln, Don

    2014-10-24

    The laws of quantum mechanics and relativity are quite perplexing however it is when the two theories are merged that things get really confusing. This combined theory predicts that empty space isn’t empty at all – it’s a seething and bubbling cauldron of matter and antimatter particles springing into existence before disappearing back into nothingness. Scientists call this complicated state of affairs “quantum foam.” In this video, Fermilab’s Dr. Don Lincoln discusses this mind-bending idea and sketches some of the experiments that have convinced scientists that this crazy prediction is actually true.

  17. TACO3D. 3-D Finite Element Heat Transfer Code

    SciTech Connect

    Mason, W.E.

    1992-03-04

    TACO3D is a three-dimensional, finite-element program for heat transfer analysis. An extension of the two-dimensional TACO program, it can perform linear and nonlinear analyses and can be used to solve either transient or steady-state problems. The program accepts time-dependent or temperature-dependent material properties, and materials may be isotropic or orthotropic. A variety of time-dependent and temperature-dependent boundary conditions and loadings are available including temperature, flux, convection, and radiation boundary conditions and internal heat generation. Additional specialized features treat enclosure radiation, bulk nodes, and master/slave internal surface conditions (e.g., contact resistance). Data input via a free-field format is provided. A user subprogram feature allows for any type of functional representation of any independent variable. A profile (bandwidth) minimization option is available. The code is limited to implicit time integration for transient solutions. TACO3D has no general mesh generation capability. Rows of evenly-spaced nodes and rows of sequential elements may be generated, but the program relies on separate mesh generators for complex zoning. TACO3D does not have the ability to calculate view factors internally. Graphical representation of data in the form of time history and spatial plots is provided through links to the POSTACO and GRAPE postprocessor codes.

  18. Electrochemical Energy Storage Application and Degradation Analysis of Carbon-Coated Hierarchical NiCo2S4 Core-Shell Nanowire Arrays Grown Directly on Graphene/Nickel Foam

    PubMed Central

    Zou, Rujia; Yuen, Muk Fung; Yu, Li; Hu, Junqing; Lee, Chun-Sing; Zhang, Wenjun

    2016-01-01

    We developed a new electrode comprising thin carbon layer coated hierarchical NiCo2S4 core-shell nanowire arrays (NiCo2S4@C CSNAs) on graphene/Ni foam (Ni@G) substrates. The electrode showed outstanding electrochemical characteristics including a high specific capacitance of 253 mAh g−1 at 3 A g−1, high rate capability of 163 mAh g−1 at 50 A g−1 (~64.4% of that at 3 A g−1), and long-term cycling stability with a capacity retention of 93.9% after 5000 cycles. Comparative studies on the degradation of hierarchical NiCo2S4 CSNA electrodes with and without carbon coatings revealed that the morphology pulverization, structural separation at core/shell interface, and irretrievably chemical composition change of NiCo2S4 CSNAs electrode are major factors that deteriorate the electrochemical performance of the electrodes without carbon coating. The favorable roles of carbon coatings on hierarchical NiCo2S4 CSNAs were further clarified: (1) serving as a physical buffering layer that suppresses the structural breakdown; (2) retarding the chemical composition conversion of the NiCo2S4 CSNAs; and (3) providing extra path for charge transition in addition to the NiCo2S4 core nanowires. Understanding of the degradation mechanisms and the significance of the surface carbon coatings would provide useful guidelines for the design of new electrode materials for high-performance electrochemical devices. PMID:26833359

  19. Fabrication of Open-Cell Al Foams and Evaluation of their Mechanical Response under Tension

    NASA Astrophysics Data System (ADS)

    Michailidis, N.; Stergioudi, F.; Omar, H.; Tsipas, D. N.

    2010-01-01

    In the present paper a novel procedure for describing the solid geometry of open cell foams is introduced, facilitating the establishment of a corresponding FEM model for simulating the material behaviour in micro-tension. Open-cell Al-foams were fabricated using the polymer impregnating method. A serial sectioning image-based process is described to capture, reproduce and visualize the exact three-dimensional (3D) microstructure of the examined foam. The generated 3D geometry of the Al-foam, derived from the synthesis of digital cross sectional images of the foam, was appropriately adjusted to build a FE model simulating the deformation conditions of the Al-foam under micro-tension loads. The obtained results enabled the visualisation of the stress fields in the Al-foam, allowing for a full investigation of its mechanical behaviour.

  20. Simulation of foam displacement in porous media

    SciTech Connect

    Kovscek, A.R.; Patzek, T.W.; Radke, C.J.

    1993-08-01

    Foam is an excellent fluid for achieving mobility control of gas in porous media. Practical application of foams for EOR processes, however requires a predictive model of foam displacement. Further, quantitative information on foam-flow behavior at reservoir flow rates and pressures is required as input to any field-scale modeling. An experimental and mechanistic-modeling study is reported for the transient flow of foam through 1.3 {mu}m{sup 2} (1.3 D) Boise sandstone at backpressures in excess of 5 MPa (700 psi) over a quality range from 0.80 to 0.99. Total superficial velocities range from as little as 0.42 to 2.20 m/day (1.4 ft/day to 7 ft/day). Sequential pressure taps and gamma-ray densitometry measure flow resistance and in-situ liquid saturations, respectively. We garner experimental pressure and saturation profiles in both the transient and steady states. Adoption of a mean-size foam-bubble conservation equation along with the traditional reservoir simulation equations allows mechanistic foam simulation. Since foam mobility depends heavily upon its texture, the bubble population balance is both useful and necessary as the role of foam texture must be incorporated into any model which seeks accurate prediction of flow properties. Our model employs capillary-pressure-dependent kinetic expressions for lamellae generation and coalescence and also a term for trapping of lamellae. Additionally, the effects of surfactant chemical transport are included. We find quantitative agreement between experimental and theoretical saturation and pressure profiles in both the transient and steady states.

  1. Forensic 3D scene reconstruction

    NASA Astrophysics Data System (ADS)

    Little, Charles Q.; Small, Daniel E.; Peters, Ralph R.; Rigdon, J. B.

    2000-05-01

    Traditionally law enforcement agencies have relied on basic measurement and imaging tools, such as tape measures and cameras, in recording a crime scene. A disadvantage of these methods is that they are slow and cumbersome. The development of a portable system that can rapidly record a crime scene with current camera imaging, 3D geometric surface maps, and contribute quantitative measurements such as accurate relative positioning of crime scene objects, would be an asset to law enforcement agents in collecting and recording significant forensic data. The purpose of this project is to develop a fieldable prototype of a fast, accurate, 3D measurement and imaging system that would support law enforcement agents to quickly document and accurately record a crime scene.

  2. 3D Printed Robotic Hand

    NASA Technical Reports Server (NTRS)

    Pizarro, Yaritzmar Rosario; Schuler, Jason M.; Lippitt, Thomas C.

    2013-01-01

    Dexterous robotic hands are changing the way robots and humans interact and use common tools. Unfortunately, the complexity of the joints and actuations drive up the manufacturing cost. Some cutting edge and commercially available rapid prototyping machines now have the ability to print multiple materials and even combine these materials in the same job. A 3D model of a robotic hand was designed using Creo Parametric 2.0. Combining "hard" and "soft" materials, the model was printed on the Object Connex350 3D printer with the purpose of resembling as much as possible the human appearance and mobility of a real hand while needing no assembly. After printing the prototype, strings where installed as actuators to test mobility. Based on printing materials, the manufacturing cost of the hand was $167, significantly lower than other robotic hands without the actuators since they have more complex assembly processes.

  3. Comparing swimsuits in 3D.

    PubMed

    van Geer, Erik; Molenbroek, Johan; Schreven, Sander; deVoogd-Claessen, Lenneke; Toussaint, Huib

    2012-01-01

    In competitive swimming, suits have become more important. These suits influence friction, pressure and wave drag. Friction drag is related to the surface properties whereas both pressure and wave drag are greatly influenced by body shape. To find a relationship between the body shape and the drag, the anthropometry of several world class female swimmers wearing different suits was accurately defined using a 3D scanner and traditional measuring methods. The 3D scans delivered more detailed information about the body shape. On the same day the swimmers did performance tests in the water with the tested suits. Afterwards the result of the performance tests and the differences found in body shape was analyzed to determine the deformation caused by a swimsuit and its effect on the swimming performance. Although the amount of data is limited because of the few test subjects, there is an indication that the deformation of the body influences the swimming performance.

  4. Forensic 3D Scene Reconstruction

    SciTech Connect

    LITTLE,CHARLES Q.; PETERS,RALPH R.; RIGDON,J. BRIAN; SMALL,DANIEL E.

    1999-10-12

    Traditionally law enforcement agencies have relied on basic measurement and imaging tools, such as tape measures and cameras, in recording a crime scene. A disadvantage of these methods is that they are slow and cumbersome. The development of a portable system that can rapidly record a crime scene with current camera imaging, 3D geometric surface maps, and contribute quantitative measurements such as accurate relative positioning of crime scene objects, would be an asset to law enforcement agents in collecting and recording significant forensic data. The purpose of this project is to develop a feasible prototype of a fast, accurate, 3D measurement and imaging system that would support law enforcement agents to quickly document and accurately record a crime scene.

  5. 3D-graphite structure

    SciTech Connect

    Belenkov, E. A. Ali-Pasha, V. A.

    2011-01-15

    The structure of clusters of some new carbon 3D-graphite phases have been calculated using the molecular-mechanics methods. It is established that 3D-graphite polytypes {alpha}{sub 1,1}, {alpha}{sub 1,3}, {alpha}{sub 1,5}, {alpha}{sub 2,1}, {alpha}{sub 2,3}, {alpha}{sub 3,1}, {beta}{sub 1,2}, {beta}{sub 1,4}, {beta}{sub 1,6}, {beta}{sub 2,1}, and {beta}{sub 3,2} consist of sp{sup 2}-hybridized atoms, have hexagonal unit cells, and differ in regards to the structure of layers and order of their alternation. A possible way to experimentally synthesize new carbon phases is proposed: the polymerization and carbonization of hydrocarbon molecules.

  6. [Real time 3D echocardiography

    NASA Technical Reports Server (NTRS)

    Bauer, F.; Shiota, T.; Thomas, J. D.

    2001-01-01

    Three-dimensional representation of the heart is an old concern. Usually, 3D reconstruction of the cardiac mass is made by successive acquisition of 2D sections, the spatial localisation and orientation of which require complex guiding systems. More recently, the concept of volumetric acquisition has been introduced. A matricial emitter-receiver probe complex with parallel data processing provides instantaneous of a pyramidal 64 degrees x 64 degrees volume. The image is restituted in real time and is composed of 3 planes (planes B and C) which can be displaced in all spatial directions at any time during acquisition. The flexibility of this system of acquisition allows volume and mass measurement with greater accuracy and reproducibility, limiting inter-observer variability. Free navigation of the planes of investigation allows reconstruction for qualitative and quantitative analysis of valvular heart disease and other pathologies. Although real time 3D echocardiography is ready for clinical usage, some improvements are still necessary to improve its conviviality. Then real time 3D echocardiography could be the essential tool for understanding, diagnosis and management of patients.

  7. GPU-Accelerated Denoising in 3D (GD3D)

    SciTech Connect

    2013-10-01

    The raw computational power GPU Accelerators enables fast denoising of 3D MR images using bilateral filtering, anisotropic diffusion, and non-local means. This software addresses two facets of this promising application: what tuning is necessary to achieve optimal performance on a modern GPU? And what parameters yield the best denoising results in practice? To answer the first question, the software performs an autotuning step to empirically determine optimal memory blocking on the GPU. To answer the second, it performs a sweep of algorithm parameters to determine the combination that best reduces the mean squared error relative to a noiseless reference image.

  8. Magmatic Systems in 3-D

    NASA Astrophysics Data System (ADS)

    Kent, G. M.; Harding, A. J.; Babcock, J. M.; Orcutt, J. A.; Bazin, S.; Singh, S.; Detrick, R. S.; Canales, J. P.; Carbotte, S. M.; Diebold, J.

    2002-12-01

    Multichannel seismic (MCS) images of crustal magma chambers are ideal targets for advanced visualization techniques. In the mid-ocean ridge environment, reflections originating at the melt-lens are well separated from other reflection boundaries, such as the seafloor, layer 2A and Moho, which enables the effective use of transparency filters. 3-D visualization of seismic reflectivity falls into two broad categories: volume and surface rendering. Volumetric-based visualization is an extremely powerful approach for the rapid exploration of very dense 3-D datasets. These 3-D datasets are divided into volume elements or voxels, which are individually color coded depending on the assigned datum value; the user can define an opacity filter to reject plotting certain voxels. This transparency allows the user to peer into the data volume, enabling an easy identification of patterns or relationships that might have geologic merit. Multiple image volumes can be co-registered to look at correlations between two different data types (e.g., amplitude variation with offsets studies), in a manner analogous to draping attributes onto a surface. In contrast, surface visualization of seismic reflectivity usually involves producing "fence" diagrams of 2-D seismic profiles that are complemented with seafloor topography, along with point class data, draped lines and vectors (e.g. fault scarps, earthquake locations and plate-motions). The overlying seafloor can be made partially transparent or see-through, enabling 3-D correlations between seafloor structure and seismic reflectivity. Exploration of 3-D datasets requires additional thought when constructing and manipulating these complex objects. As numbers of visual objects grow in a particular scene, there is a tendency to mask overlapping objects; this clutter can be managed through the effective use of total or partial transparency (i.e., alpha-channel). In this way, the co-variation between different datasets can be investigated

  9. Quantitative Analysis of the Microstructure of Auxetic Foams

    SciTech Connect

    Gaspar, N.; Smith, C.W.; Miller, E.A.; Seidler, G.T.; Evans, K.E.

    2008-07-28

    The auxetic foams first produced by Lakes have been modelled in a variety of ways, each model trying to reproduce some observed feature of the microscale of the foams. Such features include bent or broken ribs or inverted angles between ribs. These models can reproduce the Poisson's ratio or Poisson's function of auxetic foam if the model parameters are carefully chosen. However these model parameters may not actually reflect the internal structure of the foams. A big problem is that measurement of parameters such as lengths and angles is not straightforward within a 3-d sample. In this work a sample of auxetic foam has been imaged by 3-d X-ray computed tomography. The resulting image is translated to a form that emphasises the geometrical structure of connected ribs. This connected rib data are suitably analysed to describe both the microstructural construction of auxetic foams and the statistical spread of structure, that is, the heterogeneity of an auxetic foam. From the analysis of the microstructure, observations are made about the requirements for microstructural models and comparisons made to previous existing models. From the statistical data, measures of heterogeneity are made that will help with future modelling that includes the heterogeneous aspect of auxetic foams.

  10. Quantum Foam

    ScienceCinema

    Lincoln, Don

    2016-07-12

    The laws of quantum mechanics and relativity are quite perplexing however it is when the two theories are merged that things get really confusing. This combined theory predicts that empty space isn’t empty at all – it’s a seething and bubbling cauldron of matter and antimatter particles springing into existence before disappearing back into nothingness. Scientists call this complicated state of affairs “quantum foam.” In this video, Fermilab’s Dr. Don Lincoln discusses this mind-bending idea and sketches some of the experiments that have convinced scientists that this crazy prediction is actually true.

  11. Pitch based foam with particulate

    DOEpatents

    Klett, James W.

    2001-01-01

    A thermally conductive, pitch based foam composite having a particulate content. The particulate alters the mechanical characteristics of the foam without severely degrading the foam thermal conductivity. The composite is formed by mixing the particulate with pitch prior to foaming.

  12. Interactive 3D Mars Visualization

    NASA Technical Reports Server (NTRS)

    Powell, Mark W.

    2012-01-01

    The Interactive 3D Mars Visualization system provides high-performance, immersive visualization of satellite and surface vehicle imagery of Mars. The software can be used in mission operations to provide the most accurate position information for the Mars rovers to date. When integrated into the mission data pipeline, this system allows mission planners to view the location of the rover on Mars to 0.01-meter accuracy with respect to satellite imagery, with dynamic updates to incorporate the latest position information. Given this information so early in the planning process, rover drivers are able to plan more accurate drive activities for the rover than ever before, increasing the execution of science activities significantly. Scientifically, this 3D mapping information puts all of the science analyses to date into geologic context on a daily basis instead of weeks or months, as was the norm prior to this contribution. This allows the science planners to judge the efficacy of their previously executed science observations much more efficiently, and achieve greater science return as a result. The Interactive 3D Mars surface view is a Mars terrain browsing software interface that encompasses the entire region of exploration for a Mars surface exploration mission. The view is interactive, allowing the user to pan in any direction by clicking and dragging, or to zoom in or out by scrolling the mouse or touchpad. This set currently includes tools for selecting a point of interest, and a ruler tool for displaying the distance between and positions of two points of interest. The mapping information can be harvested and shared through ubiquitous online mapping tools like Google Mars, NASA WorldWind, and Worldwide Telescope.

  13. 3D Nanostructuring of Semiconductors

    NASA Astrophysics Data System (ADS)

    Blick, Robert

    2000-03-01

    Modern semiconductor technology allows to machine devices on the nanometer scale. I will discuss the current limits of the fabrication processes, which enable the definition of single electron transistors with dimensions down to 8 nm. In addition to the conventional 2D patterning and structuring of semiconductors, I will demonstrate how to apply 3D nanostructuring techniques to build freely suspended single-crystal beams with lateral dimension down to 20 nm. In transport measurements in the temperature range from 30 mK up to 100 K these nano-crystals are characterized regarding their electronic as well as their mechanical properties. Moreover, I will present possible applications of these devices.

  14. What Lies Ahead (3-D)

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This 3-D cylindrical-perspective mosaic taken by the navigation camera on the Mars Exploration Rover Spirit on sol 82 shows the view south of the large crater dubbed 'Bonneville.' The rover will travel toward the Columbia Hills, seen here at the upper left. The rock dubbed 'Mazatzal' and the hole the rover drilled in to it can be seen at the lower left. The rover's position is referred to as 'Site 22, Position 32.' This image was geometrically corrected to make the horizon appear flat.

  15. Making Inexpensive 3-D Models

    NASA Astrophysics Data System (ADS)

    Manos, Harry

    2016-03-01

    Visual aids are important to student learning, and they help make the teacher's job easier. Keeping with the TPT theme of "The Art, Craft, and Science of Physics Teaching," the purpose of this article is to show how teachers, lacking equipment and funds, can construct a durable 3-D model reference frame and a model gravity well tailored to specific class lessons. Most of the supplies are readily available in the home or at school: rubbing alcohol, a rag, two colors of spray paint, art brushes, and masking tape. The cost of these supplies, if you don't have them, is less than 20.

  16. A Clean Adirondack (3-D)

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This is a 3-D anaglyph showing a microscopic image taken of an area measuring 3 centimeters (1.2 inches) across on the rock called Adirondack. The image was taken at Gusev Crater on the 33rd day of the Mars Exploration Rover Spirit's journey (Feb. 5, 2004), after the rover used its rock abrasion tool brush to clean the surface of the rock. Dust, which was pushed off to the side during cleaning, can still be seen to the left and in low areas of the rock.

  17. 3D Printed Shelby Cobra

    SciTech Connect

    Love, Lonnie

    2015-01-09

    ORNL's newly printed 3D Shelby Cobra was showcased at the 2015 NAIAS in Detroit. This "laboratory on wheels" uses the Shelby Cobra design, celebrating the 50th anniversary of this model and honoring the first vehicle to be voted a national monument. The Shelby was printed at the Department of Energy’s Manufacturing Demonstration Facility at ORNL using the BAAM (Big Area Additive Manufacturing) machine and is intended as a “plug-n-play” laboratory on wheels. The Shelby will allow research and development of integrated components to be tested and enhanced in real time, improving the use of sustainable, digital manufacturing solutions in the automotive industry.

  18. Phonon-drag thermopower in 3D Dirac semimetals.

    PubMed

    Kubakaddi, S S

    2015-11-18

    A theory of low-temperature phonon-drag thermopower S(g) in three-dimensional (3D) Dirac semimetals has been developed considering screened electron-phonon deformation potential coupling. Numerical investigations of S(g), in the boundary scattering regime for phonons, are made in 3D Dirac semimetal Cd3As2, as a function of temperature T and electron concentration n e. S(g) is found to increase rapidly for about T  <  1 K and nearly levels off for higher T. It is also seen that S(g) increases (decreases) with decreasing n e at lower (higher) T (<2 K). A screening effect is found to be very significant, strongly affecting T and n e dependence for about  <1 K and becoming negligible at higher temperature. In the Bloch-Gruneisen (BG) regime the power laws S(g) ~ T(8) (T(4)) and S(g) ~ n(e)(-5/3)(n(e)(-1/3) with (without) screening are obtained. These laws with respect to T and n e are, respectively, characteristics of 3D phonons and Dirac 3D electrons. Comparison with diffusion thermopower S(d) shows that S (g) dominates (and is much greater than) S(d) for about T  >  0.2 K. Herring's law S(g) μ p ~ T (-1), relating phonon limited mobility μ p and S(g) in the BG regime, is shown to be valid in 3D Dirac semimetals. The results obtained here are compared with those in 3D semiconductors, low-dimensional semiconductor heterojunctions and graphene. We conclude that n e-dependent measurements, rather than T-dependent ones, provide a clearer signature of the 3D Dirac semimetal phase.

  19. Phonon-drag thermopower in 3D Dirac semimetals

    NASA Astrophysics Data System (ADS)

    Kubakaddi, S. S.

    2015-11-01

    A theory of low-temperature phonon-drag thermopower S g in three-dimensional (3D) Dirac semimetals has been developed considering screened electron-phonon deformation potential coupling. Numerical investigations of S g, in the boundary scattering regime for phonons, are made in 3D Dirac semimetal Cd3As2, as a function of temperature T and electron concentration n e. S g is found to increase rapidly for about T  <  1 K and nearly levels off for higher T. It is also seen that S g increases (decreases) with decreasing n e at lower (higher) T (<2 K). A screening effect is found to be very significant, strongly affecting T and n e dependence for about  <1 K and becoming negligible at higher temperature. In the Bloch-Gruneisen (BG) regime the power laws S g ~ T 8 (T 4) and S g ~ n\\text{e}-5/3 (n\\text{e}-1/3) with (without) screening are obtained. These laws with respect to T and n e are, respectively, characteristics of 3D phonons and Dirac 3D electrons. Comparison with diffusion thermopower S d shows that S g dominates (and is much greater than) S d for about T  >  0.2 K. Herring’s law S g μ p ~ T -1, relating phonon limited mobility μ p and S g in the BG regime, is shown to be valid in 3D Dirac semimetals. The results obtained here are compared with those in 3D semiconductors, low-dimensional semiconductor heterojunctions and graphene. We conclude that n e-dependent measurements, rather than T-dependent ones, provide a clearer signature of the 3D Dirac semimetal phase.

  20. Positional Awareness Map 3D (PAM3D)

    NASA Technical Reports Server (NTRS)

    Hoffman, Monica; Allen, Earl L.; Yount, John W.; Norcross, April Louise

    2012-01-01

    The Western Aeronautical Test Range of the National Aeronautics and Space Administration s Dryden Flight Research Center needed to address the aging software and hardware of its current situational awareness display application, the Global Real-Time Interactive Map (GRIM). GRIM was initially developed in the late 1980s and executes on older PC architectures using a Linux operating system that is no longer supported. Additionally, the software is difficult to maintain due to its complexity and loss of developer knowledge. It was decided that a replacement application must be developed or acquired in the near future. The replacement must provide the functionality of the original system, the ability to monitor test flight vehicles in real-time, and add improvements such as high resolution imagery and true 3-dimensional capability. This paper will discuss the process of determining the best approach to replace GRIM, and the functionality and capabilities of the first release of the Positional Awareness Map 3D.

  1. 3D printed bionic ears.

    PubMed

    Mannoor, Manu S; Jiang, Ziwen; James, Teena; Kong, Yong Lin; Malatesta, Karen A; Soboyejo, Winston O; Verma, Naveen; Gracias, David H; McAlpine, Michael C

    2013-06-12

    The ability to three-dimensionally interweave biological tissue with functional electronics could enable the creation of bionic organs possessing enhanced functionalities over their human counterparts. Conventional electronic devices are inherently two-dimensional, preventing seamless multidimensional integration with synthetic biology, as the processes and materials are very different. Here, we present a novel strategy for overcoming these difficulties via additive manufacturing of biological cells with structural and nanoparticle derived electronic elements. As a proof of concept, we generated a bionic ear via 3D printing of a cell-seeded hydrogel matrix in the anatomic geometry of a human ear, along with an intertwined conducting polymer consisting of infused silver nanoparticles. This allowed for in vitro culturing of cartilage tissue around an inductive coil antenna in the ear, which subsequently enables readout of inductively-coupled signals from cochlea-shaped electrodes. The printed ear exhibits enhanced auditory sensing for radio frequency reception, and complementary left and right ears can listen to stereo audio music. Overall, our approach suggests a means to intricately merge biologic and nanoelectronic functionalities via 3D printing.

  2. 3D Printed Bionic Ears

    PubMed Central

    Mannoor, Manu S.; Jiang, Ziwen; James, Teena; Kong, Yong Lin; Malatesta, Karen A.; Soboyejo, Winston O.; Verma, Naveen; Gracias, David H.; McAlpine, Michael C.

    2013-01-01

    The ability to three-dimensionally interweave biological tissue with functional electronics could enable the creation of bionic organs possessing enhanced functionalities over their human counterparts. Conventional electronic devices are inherently two-dimensional, preventing seamless multidimensional integration with synthetic biology, as the processes and materials are very different. Here, we present a novel strategy for overcoming these difficulties via additive manufacturing of biological cells with structural and nanoparticle derived electronic elements. As a proof of concept, we generated a bionic ear via 3D printing of a cell-seeded hydrogel matrix in the precise anatomic geometry of a human ear, along with an intertwined conducting polymer consisting of infused silver nanoparticles. This allowed for in vitro culturing of cartilage tissue around an inductive coil antenna in the ear, which subsequently enables readout of inductively-coupled signals from cochlea-shaped electrodes. The printed ear exhibits enhanced auditory sensing for radio frequency reception, and complementary left and right ears can listen to stereo audio music. Overall, our approach suggests a means to intricately merge biologic and nanoelectronic functionalities via 3D printing. PMID:23635097

  3. Martian terrain & airbags - 3D

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Portions of the lander's deflated airbags and a petal are at lower left in this image, taken in stereo by the Imager for Mars Pathfinder (IMP) on Sol 3. 3D glasses are necessary to identify surface detail. This image is part of a 3D 'monster' panorama of the area surrounding the landing site.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

    Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right

  4. Martian terrain & airbags - 3D

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Portions of the lander's deflated airbags and a petal are at the lower area of this image, taken in stereo by the Imager for Mars Pathfinder (IMP) on Sol 3. 3D glasses are necessary to identify surface detail. This image is part of a 3D 'monster' panorama of the area surrounding the landing site.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

    Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right

  5. 3D structured illumination microscopy

    NASA Astrophysics Data System (ADS)

    Dougherty, William M.; Goodwin, Paul C.

    2011-03-01

    Three-dimensional structured illumination microscopy achieves double the lateral and axial resolution of wide-field microscopy, using conventional fluorescent dyes, proteins and sample preparation techniques. A three-dimensional interference-fringe pattern excites the fluorescence, filling in the "missing cone" of the wide field optical transfer function, thereby enabling axial (z) discrimination. The pattern acts as a spatial carrier frequency that mixes with the higher spatial frequency components of the image, which usually succumb to the diffraction limit. The fluorescence image encodes the high frequency content as a down-mixed, moiré-like pattern. A series of images is required, wherein the 3D pattern is shifted and rotated, providing down-mixed data for a system of linear equations. Super-resolution is obtained by solving these equations. The speed with which the image series can be obtained can be a problem for the microscopy of living cells. Challenges include pattern-switching speeds, optical efficiency, wavefront quality and fringe contrast, fringe pitch optimization, and polarization issues. We will review some recent developments in 3D-SIM hardware with the goal of super-resolved z-stacks of motile cells.

  6. Hierarchical micro-lamella-structured 3D porous copper current collector coated with tin for advanced lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Park, Hyeji; Um, Ji Hyun; Choi, Hyelim; Yoon, Won-Sub; Sung, Yung-Eun; Choe, Heeman

    2017-03-01

    A Novel 3D porous Sn-Cu architecture is prepared as an anode material for use in an advanced lithium-ion battery. Micro-lamellar-structured 3D porous Cu foam, which is electroless-plated with Sn as an active material, is used as anode current collector. Compared to Sn-coated Cu foil, the 3D Sn-Cu foam exhibits superior Li-ion capacity and stable capacity retention, demonstrating the advantage of 3D porous architecture by preserving its structural integrity. In addition, the effect of heat-treatment after Sn plating is investigated. Sn/Sn6Cu5 and SnO2/Cu10Sn3 were formed on and in the 3D Sn-Cu foam under the heat-treatment at 150 °C and 500 °C, respectively. The development of Cu10Sn3 in the 3D Sn-Cu foam heat-treated at 500 °C can be a key factor for the enhanced cyclic stability because the Cu10Sn3 inactively reacts with Li-ion and alleviates the volume expansion of SnO2 as an inactive matrix.

  7. 3D X-rays application for precision measurement of the cell structure of extruded polystyrene

    NASA Astrophysics Data System (ADS)

    Lim, J. Y.; Kim, K. Y.; Shin, H. S.; Yeom, S.; Lee, S. E.

    2015-12-01

    While the thermal performance of existing insulation materials have been determined by blister gases, the thermal performance of future insulation materials will be dependent on the cell size and independent foam content as we use eco-friendly blister gases with a higher thermal conductivity. However, with the current technology we are only able to guess the whole cell size and independent foam content through SEM applied 2D fragmentary scanning but are still far from the level of accurate cell structure data extraction. Under this situation, we utilized X-ray CT scanned 3D images to identify and shape the cell structure and proposed a method of inferring the whole distribution and independent foam content as accurately as possible. According to X-ray CT scanning images and SEM images, the shape was similar but according to tracer applied CT scanning images, the cell size distribution was 380∼400 pm within the range of the general insulation diameter distribution which had the highest reliability. As for extrusion foaming polystyrene, we need additional image processing to identify the independent foam content as its density is too low. So, it is recommended to raise the 3D cell structure completeness of XPS by improving the scanning accuracy.

  8. Quasi 3D dispersion experiment

    NASA Astrophysics Data System (ADS)

    Bakucz, P.

    2003-04-01

    This paper studies the problem of tracer dispersion in a coloured fluid flowing through a two-phase 3D rough channel-system in a 40 cm*40 cm plexi-container filled by homogen glass fractions and colourless fluid. The unstable interface between the driving coloured fluid and the colourless fluid develops viscous fingers with a fractal structure at high capillary number. Five two-dimensional fractal fronts have been observed at the same time using four cameras along the vertical side-walls and using one camera located above the plexi-container. In possession of five fronts the spatial concentration contours are determined using statistical models. The concentration contours are self-affine fractal curves with a fractal dimension D=2.19. This result is valid for disperison at high Péclet numbers.

  9. ShowMe3D

    SciTech Connect

    Sinclair, Michael B

    2012-01-05

    ShowMe3D is a data visualization graphical user interface specifically designed for use with hyperspectral image obtained from the Hyperspectral Confocal Microscope. The program allows the user to select and display any single image from a three dimensional hyperspectral image stack. By moving a slider control, the user can easily move between images of the stack. The user can zoom into any region of the image. The user can select any pixel or region from the displayed image and display the fluorescence spectrum associated with that pixel or region. The user can define up to 3 spectral filters to apply to the hyperspectral image and view the image as it would appear from a filter-based confocal microscope. The user can also obtain statistics such as intensity average and variance from selected regions.

  10. 3D Printed Shelby Cobra

    ScienceCinema

    Love, Lonnie

    2016-11-02

    ORNL's newly printed 3D Shelby Cobra was showcased at the 2015 NAIAS in Detroit. This "laboratory on wheels" uses the Shelby Cobra design, celebrating the 50th anniversary of this model and honoring the first vehicle to be voted a national monument. The Shelby was printed at the Department of Energy’s Manufacturing Demonstration Facility at ORNL using the BAAM (Big Area Additive Manufacturing) machine and is intended as a “plug-n-play” laboratory on wheels. The Shelby will allow research and development of integrated components to be tested and enhanced in real time, improving the use of sustainable, digital manufacturing solutions in the automotive industry.

  11. Fire retardant polyisocyanurate foam

    NASA Technical Reports Server (NTRS)

    Riccitiello, S. R.; Parker, J. A.

    1972-01-01

    Fire retardant properties of low density polymer foam are increased. Foam has pendant nitrile groups which form thermally-stable heterocyclic structures at temperature below degradation temperature of urethane linkages.

  12. Polyurethane-Foam Maskant

    NASA Technical Reports Server (NTRS)

    Bodemeijer, R.

    1985-01-01

    Brown wax previously used to mask hardware replaced with polyurethane foam in electroplating and electroforming operations. Foam easier to apply and remove than wax and does not contaminate electrolytes.

  13. Supernova Remnant in 3-D

    NASA Technical Reports Server (NTRS)

    2009-01-01

    wavelengths. Since the amount of the wavelength shift is related to the speed of motion, one can determine how fast the debris are moving in either direction. Because Cas A is the result of an explosion, the stellar debris is expanding radially outwards from the explosion center. Using simple geometry, the scientists were able to construct a 3-D model using all of this information. A program called 3-D Slicer modified for astronomical use by the Astronomical Medicine Project at Harvard University in Cambridge, Mass. was used to display and manipulate the 3-D model. Commercial software was then used to create the 3-D fly-through.

    The blue filaments defining the blast wave were not mapped using the Doppler effect because they emit a different kind of light synchrotron radiation that does not emit light at discrete wavelengths, but rather in a broad continuum. The blue filaments are only a representation of the actual filaments observed at the blast wave.

    This visualization shows that there are two main components to this supernova remnant: a spherical component in the outer parts of the remnant and a flattened (disk-like) component in the inner region. The spherical component consists of the outer layer of the star that exploded, probably made of helium and carbon. These layers drove a spherical blast wave into the diffuse gas surrounding the star. The flattened component that astronomers were unable to map into 3-D prior to these Spitzer observations consists of the inner layers of the star. It is made from various heavier elements, not all shown in the visualization, such as oxygen, neon, silicon, sulphur, argon and iron.

    High-velocity plumes, or jets, of this material are shooting out from the explosion in the plane of the disk-like component mentioned above. Plumes of silicon appear in the northeast and southwest, while those of iron are seen in the southeast and north. These jets were already known and Doppler velocity measurements have been made for these

  14. Three dimensional graphene scaffold for cardiac tissue engineering and in-situ electrical recording.

    PubMed

    Ameri, S K; Singh, P K; D'Angelo, R; Stoppel, W; Black, L; Sonkusale, S R

    2016-08-01

    In this paper, we present a three-dimensional graphene foam made of few layers of CVD grown graphene as a scaffold for growing cardiac cells and recording their electrical activity. Our results show that graphene foam not only provides an excellent extra-cellular matrix (ECM) for the culture of such electrogenic cells but also enables recording of its extracellular electrical activity in-situ. Recording is possible due to graphene's excellent conductivity. In this paper, we present our results on the fabrication of the graphene scaffold and initial studies on the culture of cardiac cell lines such as HL-1 and recording of their real-time electrical activity.

  15. 3D Kitaev spin liquids

    NASA Astrophysics Data System (ADS)

    Hermanns, Maria

    The Kitaev honeycomb model has become one of the archetypal spin models exhibiting topological phases of matter, where the magnetic moments fractionalize into Majorana fermions interacting with a Z2 gauge field. In this talk, we discuss generalizations of this model to three-dimensional lattice structures. Our main focus is the metallic state that the emergent Majorana fermions form. In particular, we discuss the relation of the nature of this Majorana metal to the details of the underlying lattice structure. Besides (almost) conventional metals with a Majorana Fermi surface, one also finds various realizations of Dirac semi-metals, where the gapless modes form Fermi lines or even Weyl nodes. We introduce a general classification of these gapless quantum spin liquids using projective symmetry analysis. Furthermore, we briefly outline why these Majorana metals in 3D Kitaev systems provide an even richer variety of Dirac and Weyl phases than possible for electronic matter and comment on possible experimental signatures. Work done in collaboration with Kevin O'Brien and Simon Trebst.

  16. 3D multiplexed immunoplasmonics microscopy

    NASA Astrophysics Data System (ADS)

    Bergeron, Éric; Patskovsky, Sergiy; Rioux, David; Meunier, Michel

    2016-07-01

    Selective labelling, identification and spatial distribution of cell surface biomarkers can provide important clinical information, such as distinction between healthy and diseased cells, evolution of a disease and selection of the optimal patient-specific treatment. Immunofluorescence is the gold standard for efficient detection of biomarkers expressed by cells. However, antibodies (Abs) conjugated to fluorescent dyes remain limited by their photobleaching, high sensitivity to the environment, low light intensity, and wide absorption and emission spectra. Immunoplasmonics is a novel microscopy method based on the visualization of Abs-functionalized plasmonic nanoparticles (fNPs) targeting cell surface biomarkers. Tunable fNPs should provide higher multiplexing capacity than immunofluorescence since NPs are photostable over time, strongly scatter light at their plasmon peak wavelengths and can be easily functionalized. In this article, we experimentally demonstrate accurate multiplexed detection based on the immunoplasmonics approach. First, we achieve the selective labelling of three targeted cell surface biomarkers (cluster of differentiation 44 (CD44), epidermal growth factor receptor (EGFR) and voltage-gated K+ channel subunit KV1.1) on human cancer CD44+ EGFR+ KV1.1+ MDA-MB-231 cells and reference CD44- EGFR- KV1.1+ 661W cells. The labelling efficiency with three stable specific immunoplasmonics labels (functionalized silver nanospheres (CD44-AgNSs), gold (Au) NSs (EGFR-AuNSs) and Au nanorods (KV1.1-AuNRs)) detected by reflected light microscopy (RLM) is similar to the one with immunofluorescence. Second, we introduce an improved method for 3D localization and spectral identification of fNPs based on fast z-scanning by RLM with three spectral filters corresponding to the plasmon peak wavelengths of the immunoplasmonics labels in the cellular environment (500 nm for 80 nm AgNSs, 580 nm for 100 nm AuNSs and 700 nm for 40 nm × 92 nm AuNRs). Third, the developed

  17. Crowdsourcing Based 3d Modeling

    NASA Astrophysics Data System (ADS)

    Somogyi, A.; Barsi, A.; Molnar, B.; Lovas, T.

    2016-06-01

    Web-based photo albums that support organizing and viewing the users' images are widely used. These services provide a convenient solution for storing, editing and sharing images. In many cases, the users attach geotags to the images in order to enable using them e.g. in location based applications on social networks. Our paper discusses a procedure that collects open access images from a site frequently visited by tourists. Geotagged pictures showing the image of a sight or tourist attraction are selected and processed in photogrammetric processing software that produces the 3D model of the captured object. For the particular investigation we selected three attractions in Budapest. To assess the geometrical accuracy, we used laser scanner and DSLR as well as smart phone photography to derive reference values to enable verifying the spatial model obtained from the web-album images. The investigation shows how detailed and accurate models could be derived applying photogrammetric processing software, simply by using images of the community, without visiting the site.

  18. An Accurate von Neumann's Law for Three-Dimensional Foams

    SciTech Connect

    Hilgenfeldt, Sascha; Kraynik, Andrew M.; Koehler, Stephan A.; Stone, Howard A.

    2001-03-19

    The diffusive coarsening of 2D soap froths is governed by von Neumann's law. A statistical version of this law for dry 3D foams has long been conjectured. A new derivation, based on a theorem by Minkowski, yields an explicit analytical von Neumann's law in 3D which is in very good agreement with detailed simulations and experiments. The average growth rate of a bubble with F faces is shown to be proportional to F{sup 1/2} for large F , in contrast to the conjectured linear dependence. Accounting for foam disorder in the model further improves the agreement with data.

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

    NASA Astrophysics Data System (ADS)

    Yavari, Fazel

    In this dissertation we have developed graphene-based nano-devices for applications in integrated circuits and gas sensors; as well as graphene-based nano-composites for applications in structures and thermal management. First, we have studied the bandgap of graphene for semiconductor applications. Graphene as a zero-bandgap material cannot be used in the semiconductor industry unless an effective method is developed to open the bandgap in this material. We have demonstrated that a bandgap of 0.206 eV can be opened in graphene by adsorption of water vapor molecules on its surface. Water molecules break the molecular symmetries of graphene resulting in a significant bandgap opening. We also illustrate that the lack of bandgap in graphene can be used to our advantage by making sensors that are able to detect low concentrations of gas molecules mixed in air. We have shown that 1-2 layers of graphene synthesized by chemical vapor deposition enables detection of trace amounts of NO 2 and NH3 in air at room temperature and atmospheric pressure. The gas species are detected by monitoring changes in electrical resistance of the graphene film due to gas adsorption. The sensor response time is inversely proportional to the gas concentration. Heating the film expels chemisorbed molecules from the graphene surface enabling reversible operation. The detection limits of ~100 parts-per-billion (ppb) for NO2 and ~500 ppb for NH3 obtained using this device are markedly superior to commercially available NO2 and NH3 detectors. This sensor is fabricated using individual graphene sheets that are exquisitely sensitive to the chemical environment. However, the fabrication and operation of devices that use individual nanostructures for sensing is complex, expensive and suffers from poor reliability due to contamination and large variability from sample-to-sample. To overcome these problems we have developed a gas sensor based on a porous 3D network of graphene sheets called graphene foam

  20. Shooting in a foam.

    PubMed

    Le Goff, Anne; Quéré, David; Clanet, Christophe

    2014-09-21

    We study the motion of a solid sphere after its fast impact on a bath of liquid foam. We identify two regimes of deceleration. At short times, the velocity is still large and the foam behaves similar to a Newtonian fluid of constant viscosity. Then we measure a velocity threshold below which the sphere starts experiencing the foam's elasticity. We interpret this behavior using a visco-elasto-plastic model for foam rheology. Finally we discuss the possibility of stopping a projectile in the foam, and evaluate the capture efficiency.

  1. Structural graphitic carbon foams

    SciTech Connect

    Kearns, K.M.; Anderson, H.J.

    1998-12-31

    Graphitic carbon foams are a unique material form with very high structural and thermal properties at a light weight. A process has been developed to produce microcellular, open-celled graphitic foams. The process includes heating a mesophase pitch preform above the pitch melting temperature in a pressurized reactor. At the appropriate time, the pressure is released, the gas nucleates bubbles, and these bubbles grow forming the pitch into the foam structure. The resultant foamed pitch is then stabilized in an oxygen environment. At this point a rigid structure exists with some mechanical integrity. The foam is then carbonized to 800 C followed by a graphitization to 2700 C. The shear action from the growing bubbles aligns the graphitic planes along the foam struts to provide the ideal structure for good mechanical properties. Some of these properties have been characterized for some of the foam materials. It is known that variations of the blowing temperature, blowing pressure and saturation time result in foams of variously sized with mostly open pores; however, the mechanism of bubble nucleation is not known. Therefore foams were blown with various gases to begin to determine the nucleation method. These gases are comprised of a variety of molecular weights as well as a range of various solubility levels. By examining the resultant structures of the foam, differences were noted to develop an explanation of the foaming mechanism.

  2. Foam consolidation and drainage.

    PubMed

    Jun, S; Pelot, D D; Yarin, A L

    2012-03-27

    A theoretical model of foam as a consolidating continuum is proposed. The general model is applied to foam in a gravity settler. It is predicted that liquid drainage from foam in a gravity settler begins with a slow drainage stage. Next, a stage with faster drainage occurs where the drainage rate doubles compared to the initial stage. The experiments conducted within the framework of this work confirmed the theoretical predictions and allowed measurements of foam characteristics. Foams of three different concentrations of Pantene Pro-V Classic Care Solutions shampoo were studied, as well as the addition of polyethylene oxide (PEO) in one case. The shampoo's main foaming components are sodium lauryl sulfate and sodium laureth sulfate. It is shown to what extent foam drainage is slowed down by using higher shampoo concentrations and how it is further decreased by adding polymer (PEO).

  3. Foam process models.

    SciTech Connect

    Moffat, Harry K.; Noble, David R.; Baer, Thomas A.; Adolf, Douglas Brian; Rao, Rekha Ranjana; Mondy, Lisa Ann

    2008-09-01

    In this report, we summarize our work on developing a production level foam processing computational model suitable for predicting the self-expansion of foam in complex geometries. The model is based on a finite element representation of the equations of motion, with the movement of the free surface represented using the level set method, and has been implemented in SIERRA/ARIA. An empirically based time- and temperature-dependent density model is used to encapsulate the complex physics of foam nucleation and growth in a numerically tractable model. The change in density with time is at the heart of the foam self-expansion as it creates the motion of the foam. This continuum-level model uses an homogenized description of foam, which does not include the gas explicitly. Results from the model are compared to temperature-instrumented flow visualization experiments giving the location of the foam front as a function of time for our EFAR model system.

  4. [3D emulation of epicardium dynamic mapping].

    PubMed

    Lu, Jun; Yang, Cui-Wei; Fang, Zu-Xiang

    2005-03-01

    In order to realize epicardium dynamic mapping of the whole atria, 3-D graphics are drawn with OpenGL. Some source codes are introduced in the paper to explain how to produce, read, and manipulate 3-D model data.

  5. An interactive multiview 3D display system

    NASA Astrophysics Data System (ADS)

    Zhang, Zhaoxing; Geng, Zheng; Zhang, Mei; Dong, Hui

    2013-03-01

    The progresses in 3D display systems and user interaction technologies will help more effective 3D visualization of 3D information. They yield a realistic representation of 3D objects and simplifies our understanding to the complexity of 3D objects and spatial relationship among them. In this paper, we describe an autostereoscopic multiview 3D display system with capability of real-time user interaction. Design principle of this autostereoscopic multiview 3D display system is presented, together with the details of its hardware/software architecture. A prototype is built and tested based upon multi-projectors and horizontal optical anisotropic display structure. Experimental results illustrate the effectiveness of this novel 3D display and user interaction system.

  6. Vibrational stability of graphene

    NASA Astrophysics Data System (ADS)

    Hu, Yangfan; Wang, Biao

    2013-05-01

    The mechanical stability of graphene as temperature rises is analyzed based on three different self-consistent phonon (SCP) models. Compared with three-dimensional (3-D) materials, the critical temperature Ti at which instability occurs for graphene is much closer to its melting temperature Tm obtained from Monte Carlo simulation (Ti ≃ 2Tm, K. V. Zakharchenko, A. Fasolino, J. H. Los, and M. I. Katsnelson, J. Phys. Condens. Matter 23, 202202). This suggests that thermal vibration plays a significant role in melting of graphene while melting for 3-D materials is often dominated by topologic defects. This peculiar property of graphene derives from its high structural anisotropy, which is characterized by the vibrational anisotropic coefficient (VAC), defined upon its Lindermann ratios in different directions. For any carbon based material with a graphene-like structure, the VAC value must be smaller than 5.4 to maintain its stability. It is also found that the high VAC value of graphene is responsible for its negative thermal expansion coefficient at low temperature range. We believe that the VAC can be regarded as a new criterion concerning the vibrational stability of any low-dimensional (low-D) materials.

  7. Laser Based 3D Volumetric Display System

    DTIC Science & Technology

    1993-03-01

    Literature, Costa Mesa, CA July 1983. 3. "A Real Time Autostereoscopic Multiplanar 3D Display System", Rodney Don Williams, Felix Garcia, Jr., Texas...8217 .- NUMBERS LASER BASED 3D VOLUMETRIC DISPLAY SYSTEM PR: CD13 0. AUTHOR(S) PE: N/AWIU: DN303151 P. Soltan, J. Trias, W. Robinson, W. Dahlke 7...laser generated 3D volumetric images on a rotating double helix, (where the 3D displays are computer controlled for group viewing with the naked eye

  8. True 3d Images and Their Applications

    NASA Astrophysics Data System (ADS)

    Wang, Z.; wang@hzgeospace., zheng.

    2012-07-01

    A true 3D image is a geo-referenced image. Besides having its radiometric information, it also has true 3Dground coordinates XYZ for every pixels of it. For a true 3D image, especially a true 3D oblique image, it has true 3D coordinates not only for building roofs and/or open grounds, but also for all other visible objects on the ground, such as visible building walls/windows and even trees. The true 3D image breaks the 2D barrier of the traditional orthophotos by introducing the third dimension (elevation) into the image. From a true 3D image, for example, people will not only be able to read a building's location (XY), but also its height (Z). true 3D images will fundamentally change, if not revolutionize, the way people display, look, extract, use, and represent the geospatial information from imagery. In many areas, true 3D images can make profound impacts on the ways of how geospatial information is represented, how true 3D ground modeling is performed, and how the real world scenes are presented. This paper first gives a definition and description of a true 3D image and followed by a brief review of what key advancements of geospatial technologies have made the creation of true 3D images possible. Next, the paper introduces what a true 3D image is made of. Then, the paper discusses some possible contributions and impacts the true 3D images can make to geospatial information fields. At the end, the paper presents a list of the benefits of having and using true 3D images and the applications of true 3D images in a couple of 3D city modeling projects.

  9. Micromechanics of Spray-On Foam Insulation

    NASA Technical Reports Server (NTRS)

    Bednarcyk, Brett A.; Aboudi, Jacob; Arnold, Steven M.; Sullivan, Roy M.

    2007-01-01

    Understanding the thermo-mechanical response of the Space Shuttle External Tank spray-on foam insulation (SOFI) material is critical, to NASA's Return to Flight effort. This closed-cell rigid polymeric foam is used to insulate the metallic Space Shuttle External Tank, which is at cryogenic temperatures immediately prior to and during lift off. The shedding of the SOFI during ascent led to the loss of the Columbia, and eliminating/minimizing foam lass from the tank has become a priority for NASA as it seeks to resume scheduled space shuttle missions. Determining the nature of the SOFI material behavior in response to both thermal and mechanical loading plays an important role as any structural modeling of the shedding phenomenon k predicated on knowledge of the constitutive behavior of the foam. In this paper, the SOFI material has been analyzed using the High-Fidelity Generalized Method of Cells (HFGMC) micromechanics model, which has recently been extended to admit a triply-periodic 3-D repeating unit cell (RUC). Additional theoretical extensions that mere made in order to enable modeling of the closed-cell-foam material include the ability to represent internal boundaries within the RUC (to simulated internal pores) and the ability to impose an internal pressure within the simulated pores. This latter extension is crucial as two sources contribute to significant internal pressure changes within the SOFI pores. First, gas trapped in the pores during the spray process will expand or contract due to temperature changes. Second, the pore pressure will increase due to outgassing of water and other species present in the foam skeleton polymer material. With HFGMC's new pore pressure modeling capabilities, a nonlinear pressure change within the simulated pore can be imposed that accounts for both of these sources, in addition to stmdar&-thermal and mechanical loading; The triply-periodic HFGMC micromechanics model described above was implemented within NASA GRC's MAC

  10. 3D Printing and Its Urologic Applications

    PubMed Central

    Soliman, Youssef; Feibus, Allison H; Baum, Neil

    2015-01-01

    3D printing is the development of 3D objects via an additive process in which successive layers of material are applied under computer control. This article discusses 3D printing, with an emphasis on its historical context and its potential use in the field of urology. PMID:26028997

  11. Teaching Geography with 3-D Visualization Technology

    ERIC Educational Resources Information Center

    Anthamatten, Peter; Ziegler, Susy S.

    2006-01-01

    Technology that helps students view images in three dimensions (3-D) can support a broad range of learning styles. "Geo-Wall systems" are visualization tools that allow scientists, teachers, and students to project stereographic images and view them in 3-D. We developed and presented 3-D visualization exercises in several undergraduate courses.…

  12. Expanding Geometry Understanding with 3D Printing

    ERIC Educational Resources Information Center

    Cochran, Jill A.; Cochran, Zane; Laney, Kendra; Dean, Mandi

    2016-01-01

    With the rise of personal desktop 3D printing, a wide spectrum of educational opportunities has become available for educators to leverage this technology in their classrooms. Until recently, the ability to create physical 3D models was well beyond the scope, skill, and budget of many schools. However, since desktop 3D printers have become readily…

  13. Beowulf 3D: a case study

    NASA Astrophysics Data System (ADS)

    Engle, Rob

    2008-02-01

    This paper discusses the creative and technical challenges encountered during the production of "Beowulf 3D," director Robert Zemeckis' adaptation of the Old English epic poem and the first film to be simultaneously released in IMAX 3D and digital 3D formats.

  14. 3D Flow Visualization Using Texture Advection

    NASA Technical Reports Server (NTRS)

    Kao, David; Zhang, Bing; Kim, Kwansik; Pang, Alex; Moran, Pat (Technical Monitor)

    2001-01-01

    Texture advection is an effective tool for animating and investigating 2D flows. In this paper, we discuss how this technique can be extended to 3D flows. In particular, we examine the use of 3D and 4D textures on 3D synthetic and computational fluid dynamics flow fields.

  15. Porous decellularized adipose tissue foams for soft tissue regeneration.

    PubMed

    Yu, Claire; Bianco, Juares; Brown, Cody; Fuetterer, Lydia; Watkins, John F; Samani, Abbas; Flynn, Lauren E

    2013-04-01

    To design tissue-specific bioscaffolds with well-defined properties and 3-D architecture, methods were developed for preparing porous foams from enzyme-solubilized human decellularized adipose tissue (DAT). Additionally, a technique was established for fabricating "bead foams" comprised of interconnected networks of porous DAT beads fused through a controlled freeze-thawing and lyophilization procedure. In characterization studies, the foams were stable without the need for chemical crosslinking, with properties that could be tuned by controlling the protein concentration and freezing rate during synthesis. Adipogenic differentiation studies with human adipose-derived stem cells (ASCs) suggested that stiffness influenced ASC adipogenesis on the foams. In support of our previous work with DAT scaffolds and microcarriers, the DAT foams and bead foams strongly supported adipogenesis and were also adipo-inductive, as demonstrated by glycerol-3-phosphate dehydrogenase (GPDH) enzyme activity, endpoint RT-PCR analysis of adipogenic gene expression, and intracellular lipid accumulation. Adipogenic differentiation was enhanced on the microporous DAT foams, potentially due to increased cell-cell interactions in this group. In vivo assessment in a subcutaneous Wistar rat model demonstrated that the DAT bioscaffolds were well tolerated and integrated into the host tissues, supporting angiogenesis and adipogenesis. The DAT-based foams induced a strong angiogenic response, promoted inflammatory cell migration and gradually resorbed over the course of 12 weeks, demonstrating potential as scaffolds for wound healing and soft tissue regeneration.

  16. High-strength cellular ceramic composites with 3D microarchitecture

    PubMed Central

    Bauer, Jens; Hengsbach, Stefan; Tesari, Iwiza; Schwaiger, Ruth; Kraft, Oliver

    2014-01-01

    To enhance the strength-to-weight ratio of a material, one may try to either improve the strength or lower the density, or both. The lightest solid materials have a density in the range of 1,000 kg/m3; only cellular materials, such as technical foams, can reach considerably lower values. However, compared with corresponding bulk materials, their specific strength generally is significantly lower. Cellular topologies may be divided into bending- and stretching-dominated ones. Technical foams are structured randomly and behave in a bending-dominated way, which is less weight efficient, with respect to strength, than stretching-dominated behavior, such as in regular braced frameworks. Cancellous bone and other natural cellular solids have an optimized architecture. Their basic material is structured hierarchically and consists of nanometer-size elements, providing a benefit from size effects in the material strength. Designing cellular materials with a specific microarchitecture would allow one to exploit the structural advantages of stretching-dominated constructions as well as size-dependent strengthening effects. In this paper, we demonstrate that such materials may be fabricated. Applying 3D laser lithography, we produced and characterized micro-truss and -shell structures made from alumina–polymer composite. Size-dependent strengthening of alumina shells has been observed, particularly when applied with a characteristic thickness below 100 nm. The presented artificial cellular materials reach compressive strengths up to 280 MPa with densities well below 1,000 kg/m3. PMID:24550268

  17. Fabrication of Reticulated Graphitic Foam.

    DTIC Science & Technology

    2007-11-02

    mesophase pitch (MP). Mesophase pitch is...goes through several heat treatments to stabilize the mesophase pitch , burn out the polyurethane, carbonize and finally graphitize the foam, all the while maintaining the same morphology as the initial polyurethane foam....struts gives some initial molecular orientation. The dipped foam is dried, leaving behind a the polyurethane foam coated with the pitch . The foam

  18. 3-D Perspective Pasadena, California

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This perspective view shows the western part of the city of Pasadena, California, looking north towards the San Gabriel Mountains. Portions of the cities of Altadena and La Canada, Flintridge are also shown. The image was created from three datasets: the Shuttle Radar Topography Mission (SRTM) supplied the elevation data; Landsat data from November 11, 1986 provided the land surface color (not the sky) and U.S. Geological Survey digital aerial photography provides the image detail. The Rose Bowl, surrounded by a golf course, is the circular feature at the bottom center of the image. The Jet Propulsion Laboratory is the cluster of large buildings north of the Rose Bowl at the base of the mountains. A large landfill, Scholl Canyon, is the smooth area in the lower left corner of the scene. This image shows the power of combining data from different sources to create planning tools to study problems that affect large urban areas. In addition to the well-known earthquake hazards, Southern California is affected by a natural cycle of fire and mudflows. Wildfires strip the mountains of vegetation, increasing the hazards from flooding and mudflows for several years afterwards. Data such as shown on this image can be used to predict both how wildfires will spread over the terrain and also how mudflows will be channeled down the canyons. The Shuttle Radar Topography Mission (SRTM), launched on February 11, 2000, uses the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. The mission was designed to collect three dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, an additional C-band imaging antenna and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency

  19. Operator spin foam models

    NASA Astrophysics Data System (ADS)

    Bahr, Benjamin; Hellmann, Frank; Kamiński, Wojciech; Kisielowski, Marcin; Lewandowski, Jerzy

    2011-05-01

    The goal of this paper is to introduce a systematic approach to spin foams. We define operator spin foams, that is foams labelled by group representations and operators, as our main tool. A set of moves we define in the set of the operator spin foams (among other operations) allows us to split the faces and the edges of the foams. We assign to each operator spin foam a contracted operator, by using the contractions at the vertices and suitably adjusted face amplitudes. The emergence of the face amplitudes is the consequence of assuming the invariance of the contracted operator with respect to the moves. Next, we define spin foam models and consider the class of models assumed to be symmetric with respect to the moves we have introduced, and assuming their partition functions (state sums) are defined by the contracted operators. Briefly speaking, those operator spin foam models are invariant with respect to the cellular decomposition, and are sensitive only to the topology and colouring of the foam. Imposing an extra symmetry leads to a family we call natural operator spin foam models. This symmetry, combined with assumed invariance with respect to the edge splitting move, determines a complete characterization of a general natural model. It can be obtained by applying arbitrary (quantum) constraints on an arbitrary BF spin foam model. In particular, imposing suitable constraints on a spin(4) BF spin foam model is exactly the way we tend to view 4D quantum gravity, starting with the BC model and continuing with the Engle-Pereira-Rovelli-Livine (EPRL) or Freidel-Krasnov (FK) models. That makes our framework directly applicable to those models. Specifically, our operator spin foam framework can be translated into the language of spin foams and partition functions. Among our natural spin foam models there are the BF spin foam model, the BC model, and a model corresponding to the EPRL intertwiners. Our operator spin foam framework can also be used for more general spin

  20. Hydrodynamics of wet foams

    NASA Astrophysics Data System (ADS)

    Langevin, Dominique; Saint-Jalmes, Arnaud; Marze, Sébastien; Cox, Simon; Hutzler, Stefan; Drenckhan, Wiebke; Weaire, Denis; Caps, Hervé; Vandewalle, Nicolas; Adler, Micheàle; Pitois, Olivier; Rouyer, Florence; Cohen-Addad, Sylvie; Höhler, Reinhard; Ritacco, Hernan

    2005-10-01

    Foams and foaming pose important questions and problems to the chemical industry. As a material, foam is unusual in being a desired product while also being an unwanted byproduct within industry. Liquid foams are an essential part of gas/liquid contacting processes such as distillation and absorption, but over-production of foam in these processes can lead to downtime and loss of efficiency. Solid polymeric foams, such as polystyrene and polyurethane, find applications as insulation panels in the construction industry. Their combination of low weight and unique elastic/plastic properties make them ideal as packing and cushioning materials. Foams made with proteins are extensively used in the food industry. Despite the fact that foam science is a rapidly maturing field, critical aspects of foam physics and chemistry remain unclear. Several gaps in knowledge were identified to be tackled as the core of this MAP project. In addition, microgravity affords conditions for extending our understanding far beyond the possibilities offered by ground-based investigation. This MAP project addresses the challenges posed by the physics of foams under microgravity.

  1. Electrodeposited lead-foam grids on copper-foam substrates as positive current collectors for lead-acid batteries

    NASA Astrophysics Data System (ADS)

    Ji, Keju; Xu, Chen; Zhao, Huihui; Dai, Zhendong

    2014-02-01

    Contemporary lead-acid batteries have a high internal resistance and a limited utilization of their positive active materials (PAM). In order to alleviate these problems, lead (alloy) foam-based positive electrodes for lead-acid batteries are prepared by electrodepositing lead on a copper-foam substrate. Using scanning electron microscopy, flame atomic absorption spectrometry, finite element analysis, cyclic voltammetry, and galvanostatic charge/discharge tests, the effect of the lead foam collectors on the electrochemical performance of the positive electrodes is characterized. The thickness of the lead coating has a strong effect on the corrosion-stability of the copper-foam substrate. In addition, the charge/discharge performance of the batteries is greatly improved by the lead-foam collectors. At the 20-2 h discharge rates, the utilization efficiency of the PAM of 40-PPI lead-foam battery is improved by 19-36% from the cast-grid battery. Combined with the finite element analysis, it appears that the 3D connected network structure of the positive lead foam electrode can reduce the surface current density, the polarization resistance, and the ohmic resistance of the battery because of its larger contact area with the active material. As a result, the lead foam battery has a higher utilization efficiency of the PAM.

  2. Flame retardancy and thermal stability of polyurethane foam composites containing carbon additives

    NASA Astrophysics Data System (ADS)

    Lee, Pyoung-Chan; Kim, Bo-Ram; Jeoung, Sun Kyoung; Lee, Geesoo; Han, San Wook; Kim, Hyunchul; Lee, Ki-Dong; Han, Joo-Kwon

    2016-03-01

    Polyurethane (PU) is an important class of polymers that have wide application in a number of different industrial sectors. The goal of this work was the synthesis of flame-retarded PU foam with expandable graphite (EG) or commercial graphene. The flame retardancy and thermal stability of the foams has been studied through cone calorimeter analysis, the limited oxygen index and thermal conductivity. The presence of expandable graphite brings an improvement in fire behavior. In particular, the limited oxygen index increases in a linear way and the highest limited oxygen index values are obtained for EG-PU foams. The results from the cone calorimeter are in agreement with those of oxygen index; EG filled foams show a considerable decrease of maximum-heat release rate (M-HRR) with respect to unfilled foams. The results of thermal conductivity show that an increase in expandable graphite amount in PU foams lead to an increased conductivity.

  3. Case study: Beauty and the Beast 3D: benefits of 3D viewing for 2D to 3D conversion

    NASA Astrophysics Data System (ADS)

    Handy Turner, Tara

    2010-02-01

    From the earliest stages of the Beauty and the Beast 3D conversion project, the advantages of accurate desk-side 3D viewing was evident. While designing and testing the 2D to 3D conversion process, the engineering team at Walt Disney Animation Studios proposed a 3D viewing configuration that not only allowed artists to "compose" stereoscopic 3D but also improved efficiency by allowing artists to instantly detect which image features were essential to the stereoscopic appeal of a shot and which features had minimal or even negative impact. At a time when few commercial 3D monitors were available and few software packages provided 3D desk-side output, the team designed their own prototype devices and collaborated with vendors to create a "3D composing" workstation. This paper outlines the display technologies explored, final choices made for Beauty and the Beast 3D, wish-lists for future development and a few rules of thumb for composing compelling 2D to 3D conversions.

  4. Mini 3D for shallow gas reconnaissance

    SciTech Connect

    Vallieres, T. des; Enns, D.; Kuehn, H.; Parron, D.; Lafet, Y.; Van Hulle, D.

    1996-12-31

    The Mini 3D project was undertaken by TOTAL and ELF with the support of CEPM (Comite d`Etudes Petrolieres et Marines) to define an economical method of obtaining 3D seismic HR data for shallow gas assessment. An experimental 3D survey was carried out with classical site survey techniques in the North Sea. From these data 19 simulations, were produced to compare different acquisition geometries ranging from dual, 600 m long cables to a single receiver. Results show that short offset, low fold and very simple streamer positioning are sufficient to give a reliable 3D image of gas charged bodies. The 3D data allow a much more accurate risk delineation than 2D HR data. Moreover on financial grounds Mini-3D is comparable in cost to a classical HR 2D survey. In view of these results, such HR 3D should now be the standard for shallow gas surveying.

  5. Ultrasonication assisted preparation of carbonaceous nanoparticles modified polyurethane foam with good conductivity and high oil absorption properties

    NASA Astrophysics Data System (ADS)

    Shi, Hengchong; Shi, Dean; Yin, Ligang; Yang, Zhihua; Luan, Shifang; Gao, Jiefeng; Zha, Junwei; Yin, Jinghua; Li, Robert K. Y.

    2014-10-01

    In this work, we report a facile, low cost and time-saving method for the fabrication of compressible, electrically conductive, oil absorptive, cost-effective and flexible polyurethane (PU) foam through ultrasonication induced carbonaceous nanoparticles (CNP) onto flexible PU foam (CNP-PU foam). SEM images showed that the CNP could be firmly anchored onto the PU foam, and made the PU foam surface much rougher. Zero-dimensional carbonaceous nanoparticles were easier to anchor onto the PU foam surface than one-dimensional nanoparticles (e.g., carbon nanotube) or two-dimensional nanoparticles (e.g., graphene oxide). The CNP-PU foam exhibited excellent elasticity and high mechanical durability even when it was subjected to 500 cyclic compression. The CNP-PU foam had excellent absorption of organic solvents up to 121 times the weight of the initial PU foam. In addition, the electrical conductivity of PU foams was considerably increased with the anchoring of CNP onto the matrix. In addition, compression experiments confirmed that the electrical conductivity of CNP-PU foams changed with their compression ratios, thus exhibiting excellent pressure sensitivity. The as-prepared materials have significant potential as oil absorbents, elastic conductors, flexible electrodes, pressure sensors, etc.In this work, we report a facile, low cost and time-saving method for the fabrication of compressible, electrically conductive, oil absorptive, cost-effective and flexible polyurethane (PU) foam through ultrasonication induced carbonaceous nanoparticles (CNP) onto flexible PU foam (CNP-PU foam). SEM images showed that the CNP could be firmly anchored onto the PU foam, and made the PU foam surface much rougher. Zero-dimensional carbonaceous nanoparticles were easier to anchor onto the PU foam surface than one-dimensional nanoparticles (e.g., carbon nanotube) or two-dimensional nanoparticles (e.g., graphene oxide). The CNP-PU foam exhibited excellent elasticity and high mechanical

  6. Noncovalent Functionalization of Graphene and Graphene Oxide for Energy Materials, Biosensing, Catalytic, and Biomedical Applications.

    PubMed

    Georgakilas, Vasilios; Tiwari, Jitendra N; Kemp, K Christian; Perman, Jason A; Bourlinos, Athanasios B; Kim, Kwang S; Zboril, Radek

    2016-05-11

    This Review focuses on noncovalent functionalization of graphene and graphene oxide with various species involving biomolecules, polymers, drugs, metals and metal oxide-based nanoparticles, quantum dots, magnetic nanostructures, other carbon allotropes (fullerenes, nanodiamonds, and carbon nanotubes), and graphene analogues (MoS2, WS2). A brief description of π-π interactions, van der Waals forces, ionic interactions, and hydrogen bonding allowing noncovalent modification of graphene and graphene oxide is first given. The main part of this Review is devoted to tailored functionalization for applications in drug delivery, energy materials, solar cells, water splitting, biosensing, bioimaging, environmental, catalytic, photocatalytic, and biomedical technologies. A significant part of this Review explores the possibilities of graphene/graphene oxide-based 3D superstructures and their use in lithium-ion batteries. This Review ends with a look at challenges and future prospects of noncovalently modified graphene and graphene oxide.

  7. 3D Interconnected Electrode Materials with Ultrahigh Areal Sulfur Loading for Li-S Batteries.

    PubMed

    Fang, Ruopian; Zhao, Shiyong; Hou, Pengxiang; Cheng, Min; Wang, Shaogang; Cheng, Hui-Ming; Liu, Chang; Li, Feng

    2016-05-01

    Sulfur electrodes based on a 3D integrated hollow carbon fiber foam (HCFF) are synthesized with high sulfur loadings of 6.2-21.2 mg cm(-2) . Benefiting from the high electrolyte absorbability of the HCFF and the multiple conductive channels, the obtained electrode demonstrates excellent cycling stability and a high areal capacity of 23.32 mAh cm(-2) , showing great promise in commercially viable Li-S batteries.

  8. Self-Assembled Three-Dimensional Graphene-Based Polyhedrons Inducing Volumetric Light Confinement.

    PubMed

    Joung, Daeha; Nemilentsau, Andrei; Agarwal, Kriti; Dai, Chunhui; Liu, Chao; Su, Qun; Li, Jing; Low, Tony; Koester, Steven J; Cho, Jeong-Hyun

    2017-03-08

    The ability to transform two-dimensional (2D) materials into a three-dimensional (3D) structure while preserving their unique inherent properties might offer great enticing opportunities in the development of diverse applications for next generation micro/nanodevices. Here, a self-assembly process is introduced for building free-standing 3D, micro/nanoscale, hollow, polyhedral structures configured with a few layers of graphene-based materials: graphene and graphene oxide. The 3D structures have been further modified with surface patterning, realized through the inclusion of metal patterns on their 3D surfaces. The 3D geometry leads to a nontrivial spatial distribution of strong electric fields (volumetric light confinement) induced by 3D plasmon hybridization on the surface of the graphene forming the 3D structures. Due to coupling in all directions, resulting in 3D plasmon hybridization, the 3D closed box graphene generates a highly confined electric field within as well as outside of the cubes. Moreover, since the uniform coupling reduces the decay of the field enhancement away from the surface, the confined electric field inside of the 3D structure shows two orders of magnitude higher than that of 2D graphene before transformation into the 3D structure. Therefore, these structures might be used for detection of target substances (not limited to only the graphene surfaces, but using the entire volume formed by the 3D graphene-based structure) in sensor applications.

  9. Structure of Random Foam

    NASA Astrophysics Data System (ADS)

    Kraynik, Andrew M.; Reinelt, Douglas A.; van Swol, Frank

    2004-11-01

    The Surface Evolver was used to compute the equilibrium microstructure of dry soap foams with random structure and a wide range of cell-size distributions. Topological and geometric properties of foams and individual cells were evaluated. The theory for isotropic Plateau polyhedra describes the dependence of cell geometric properties on their volume and number of faces. The surface area of all cells is about 10% greater than a sphere of equal volume; this leads to a simple but accurate theory for the surface free energy density of foam. A novel parameter based on the surface-volume mean bubble radius R32 is used to characterize foam polydispersity. The foam energy, total cell edge length, and average number of faces per cell all decrease with increasing polydispersity. Pentagonal faces are the most common in monodisperse foam but quadrilaterals take over in highly polydisperse structures.

  10. Orbital foamed material extruder

    NASA Technical Reports Server (NTRS)

    Tucker, Dennis S. (Inventor)

    2009-01-01

    This invention is a process for producing foamed material in space comprising the steps of: rotating the material to simulate the force of gravity; heating the rotating material until it is molten; extruding the rotating, molten material; injecting gas into the extruded, rotating, molten material to produce molten foamed material; allowing the molten foamed material to cool to below melting temperature to produce the foamed material. The surface of the extruded foam may be heated to above melting temperature and allowed to cool to below melting temperature. The extruded foam may also be cut to predetermined length. The starting material may be metal or glass. Heating may be accomplished by electrical heating elements or by solar heating.

  11. Amorphous metallic foam

    NASA Astrophysics Data System (ADS)

    Schroers, Jan; Veazey, Chris; Johnson, William L.

    2003-01-01

    The bulk glass forming alloy Pd43Ni10Cu27P20 is processed into a low-density amorphous metallic foam. Pd43Ni10Cu27P20 is mixed with hydrated B2O3, which releases gas at elevated temperature and/or low pressure. Very homogeneous foams are achieved due to the high viscosity of the alloy even at its liquidus temperature. By processing at the liquidus temperature and decreasing the pressure to 10-2 mbar, well-distributed bubbles expand to foam the material. Foam densities as low as 1.4×103 kg/m3 were obtained, corresponding to a bubble volume fraction of 84%. The bubble diameter ranges between 2×10-4 and 1×10-3 m. Thermal analysis by differential scanning calorimetry confirms the amorphous nature of the foam. Furthermore, it reveals that the foam's thermal stability is comparable to the bulk material.

  12. Structure of random foam.

    SciTech Connect

    Reinelt, Douglas A.; van Swol, Frank B.; Kraynik, Andrew Michael

    2004-06-01

    The Surface Evolver was used to compute the equilibrium microstructure of dry soap foams with random structure and a wide range of cell-size distributions. Topological and geometric properties of foams and individual cells were evaluated. The theory for isotropic Plateau polyhedra describes the dependence of cell geometric properties on their volume and number of faces. The surface area of all cells is about 10% greater than a sphere of equal volume; this leads to a simple but accurate theory for the surface free energy density of foam. A novel parameter based on the surface-volume mean bubble radius R32 is used to characterize foam polydispersity. The foam energy, total cell edge length, and average number of faces per cell all decrease with increasing polydispersity. Pentagonal faces are the most common in monodisperse foam but quadrilaterals take over in highly polydisperse structures.

  13. Fire-retardant foams

    NASA Technical Reports Server (NTRS)

    Gagliani, J.

    1978-01-01

    Family of polyimide resins are being developed as foams with exceptional fire-retardant properties. Foams are potentially useful for seat cushions in aircraft and ground vehicles and for applications such as home furnishings and building-construction materials. Basic formulations can be modified with reinforcing fibers or fillers to produce celular materials for variety of applications. By selecting reactants, polymer structure can be modified to give foams with properties ranging from high resiliency and flexibility to brittleness and rigidity.

  14. High performance polymeric foams

    SciTech Connect

    Gargiulo, M.; Sorrentino, L.; Iannace, S.

    2008-08-28

    The aim of this work was to investigate the foamability of high-performance polymers (polyethersulfone, polyphenylsulfone, polyetherimide and polyethylenenaphtalate). Two different methods have been used to prepare the foam samples: high temperature expansion and two-stage batch process. The effects of processing parameters (saturation time and pressure, foaming temperature) on the densities and microcellular structures of these foams were analyzed by using scanning electron microscopy.

  15. 3-D Technology Approaches for Biological Ecologies

    NASA Astrophysics Data System (ADS)

    Liu, Liyu; Austin, Robert; U. S-China Physical-Oncology Sciences Alliance (PS-OA) Team

    Constructing three dimensional (3-D) landscapes is an inevitable issue in deep study of biological ecologies, because in whatever scales in nature, all of the ecosystems are composed by complex 3-D environments and biological behaviors. Just imagine if a 3-D technology could help complex ecosystems be built easily and mimic in vivo microenvironment realistically with flexible environmental controls, it will be a fantastic and powerful thrust to assist researchers for explorations. For years, we have been utilizing and developing different technologies for constructing 3-D micro landscapes for biophysics studies in in vitro. Here, I will review our past efforts, including probing cancer cell invasiveness with 3-D silicon based Tepuis, constructing 3-D microenvironment for cell invasion and metastasis through polydimethylsiloxane (PDMS) soft lithography, as well as explorations of optimized stenting positions for coronary bifurcation disease with 3-D wax printing and the latest home designed 3-D bio-printer. Although 3-D technologies is currently considered not mature enough for arbitrary 3-D micro-ecological models with easy design and fabrication, I hope through my talk, the audiences will be able to sense its significance and predictable breakthroughs in the near future. This work was supported by the State Key Development Program for Basic Research of China (Grant No. 2013CB837200), the National Natural Science Foundation of China (Grant No. 11474345) and the Beijing Natural Science Foundation (Grant No. 7154221).

  16. 3D change detection - Approaches and applications

    NASA Astrophysics Data System (ADS)

    Qin, Rongjun; Tian, Jiaojiao; Reinartz, Peter

    2016-12-01

    Due to the unprecedented technology development of sensors, platforms and algorithms for 3D data acquisition and generation, 3D spaceborne, airborne and close-range data, in the form of image based, Light Detection and Ranging (LiDAR) based point clouds, Digital Elevation Models (DEM) and 3D city models, become more accessible than ever before. Change detection (CD) or time-series data analysis in 3D has gained great attention due to its capability of providing volumetric dynamics to facilitate more applications and provide more accurate results. The state-of-the-art CD reviews aim to provide a comprehensive synthesis and to simplify the taxonomy of the traditional remote sensing CD techniques, which mainly sit within the boundary of 2D image/spectrum analysis, largely ignoring the particularities of 3D aspects of the data. The inclusion of 3D data for change detection (termed 3D CD), not only provides a source with different modality for analysis, but also transcends the border of traditional top-view 2D pixel/object-based analysis to highly detailed, oblique view or voxel-based geometric analysis. This paper reviews the recent developments and applications of 3D CD using remote sensing and close-range data, in support of both academia and industry researchers who seek for solutions in detecting and analyzing 3D dynamics of various objects of interest. We first describe the general considerations of 3D CD problems in different processing stages and identify CD types based on the information used, being the geometric comparison and geometric-spectral analysis. We then summarize relevant works and practices in urban, environment, ecology and civil applications, etc. Given the broad spectrum of applications and different types of 3D data, we discuss important issues in 3D CD methods. Finally, we present concluding remarks in algorithmic aspects of 3D CD.

  17. RT3D tutorials for GMS users

    SciTech Connect

    Clement, T.P.; Jones, N.L.

    1998-02-01

    RT3D (Reactive Transport in 3-Dimensions) is a computer code that solves coupled partial differential equations that describe reactive-flow and transport of multiple mobile and/or immobile species in a three dimensional saturated porous media. RT3D was developed from the single-species transport code, MT3D (DoD-1.5, 1997 version). As with MT3D, RT3D also uses the USGS groundwater flow model MODFLOW for computing spatial and temporal variations in groundwater head distribution. This report presents a set of tutorial problems that are designed to illustrate how RT3D simulations can be performed within the Department of Defense Groundwater Modeling System (GMS). GMS serves as a pre- and post-processing interface for RT3D. GMS can be used to define all the input files needed by RT3D code, and later the code can be launched from within GMS and run as a separate application. Once the RT3D simulation is completed, the solution can be imported to GMS for graphical post-processing. RT3D v1.0 supports several reaction packages that can be used for simulating different types of reactive contaminants. Each of the tutorials, described below, provides training on a different RT3D reaction package. Each reaction package has different input requirements, and the tutorials are designed to describe these differences. Furthermore, the tutorials illustrate the various options available in GMS for graphical post-processing of RT3D results. Users are strongly encouraged to complete the tutorials before attempting to use RT3D and GMS on a routine basis.

  18. Progress in 3D Printing of Carbon Materials for Energy-Related Applications.

    PubMed

    Fu, Kun; Yao, Yonggang; Dai, Jiaqi; Hu, Liangbing

    2017-03-01

    The additive-manufacturing (AM) technique, known as three-dimensional (3D) printing, has attracted much attention in industry and academia in recent years. 3D printing has been developed for a variety of applications. Printable inks are the most important component for 3D printing, and are related to the materials, the printing method, and the structures of the final 3D-printed products. Carbon materials, due to their good chemical stability and versatile nanostructure, have been widely used in 3D printing for different applications. Good inks are mainly based on volatile solutions having carbon materials as fillers such as graphene oxide (GO), carbon nanotubes (CNT), carbon blacks, and solvent, as well as polymers and other additives. Studies of carbon materials in 3D printing, especially GO-based materials, have been extensively reported for energy-related applications. In these circumstances, understanding the very recent developments of 3D-printed carbon materials and their extended applications to address energy-related challenges and bring new concepts for material designs are becoming urgent and important. Here, recent developments in 3D printing of emerging devices for energy-related applications are reviewed, including energy-storage applications, electronic circuits, and thermal-energy applications at high temperature. To close, a conclusion and outlook are provided, pointing out future designs and developments of 3D-printing technology based on carbon materials for energy-related applications and beyond.

  19. Numerical modelling of closed-cell aluminium foams under shock loading

    NASA Astrophysics Data System (ADS)

    Kader, M. A.; Islam, M. A.; Hazell, P. J.; Escobedo, J. P.; Saadatfar, M.; Brown, A. D.

    2017-01-01

    The present research numerically investigates shock propagation through closed-cell aluminium foam via flyer-plate impact. The mechanics of foam deformation was elucidated using the finite element (FE) software ABAQUS/explicit. X-ray computed micro-tomography was performed to render a full 3D foam geometry mesh for understanding detailed macrostructural response due to shock propagation. Elastic wave propagation and pore collapse mechanism with time were studied. The free surface velocity of the foam was measured at two different flyer-plate impact velocities to observe the profile of the shock wave with time. Good correlations were observed between experimental data and FE predictions for both test conditions.

  20. Digital 3D facial reconstruction of George Washington

    NASA Astrophysics Data System (ADS)

    Razdan, Anshuman; Schwartz, Jeff; Tocheri, Mathew; Hansford, Dianne

    2006-02-01

    PRISM is a focal point of interdisciplinary research in geometric modeling, computer graphics and visualization at Arizona State University. Many projects in the last ten years have involved laser scanning, geometric modeling and feature extraction from such data as archaeological vessels, bones, human faces, etc. This paper gives a brief overview of a recently completed project on the 3D reconstruction of George Washington (GW). The project brought together forensic anthropologists, digital artists and computer scientists in the 3D digital reconstruction of GW at 57, 45 and 19 including detailed heads and bodies. Although many other scanning projects such as the Michelangelo project have successfully captured fine details via laser scanning, our project took it a step further, i.e. to predict what that individual (in the sculpture) might have looked like both in later and earlier years, specifically the process to account for reverse aging. Our base data was GWs face mask at Morgan Library and Hudons bust of GW at Mount Vernon, both done when GW was 53. Additionally, we scanned the statue at the Capitol in Richmond, VA; various dentures, and other items. Other measurements came from clothing and even portraits of GW. The digital GWs were then milled in high density foam for a studio to complete the work. These will be unveiled at the opening of the new education center at Mt Vernon in fall 2006.

  1. 3D measurement for rapid prototyping

    NASA Astrophysics Data System (ADS)

    Albrecht, Peter; Lilienblum, Tilo; Sommerkorn, Gerd; Michaelis, Bernd

    1996-08-01

    Optical 3-D measurement is an interesting approach for rapid prototyping. On one hand it's necessary to get the 3-D data of an object and on the other hand it's necessary to check the manufactured object (quality checking). Optical 3-D measurement can realize both. Classical 3-D measurement procedures based on photogrammetry cause systematic errors at strongly curved surfaces or steps in surfaces. One possibility to reduce these errors is to calculate the 3-D coordinates from several successively taken images. Thus it's possible to get higher spatial resolution and to reduce the systematic errors at 'problem surfaces.' Another possibility is to process the measurement values by neural networks. A modified associative memory smoothes and corrects the calculated 3-D coordinates using a-priori knowledge about the measurement object.

  2. Multifunctional Porous Graphene for High-Efficiency Steam Generation by Heat Localization.

    PubMed

    Ito, Yoshikazu; Tanabe, Yoichi; Han, Jiuhui; Fujita, Takeshi; Tanigaki, Katsumi; Chen, Mingwei

    2015-08-05

    Multifunctional nanoporous graphene is realized as a heat generator to convert solar illumination into high-energy steam. The novel 3D nanoporous graphene demonstrates a highly energy-effective steam generation with an energy conversation of 80%.

  3. Photorefractive Polymers for Updateable 3D Displays

    DTIC Science & Technology

    2010-02-24

    Final Performance Report 3. DATES COVERED (From - To) 01-01-2007 to 11-30-2009 4. TITLE AND SUBTITLE Photorefractive Polymers for Updateable 3D ...ABSTRACT During the tenure of this project a large area updateable 3D color display has been developed for the first time using a new co-polymer...photorefractive polymers have been demonstrated. Moreover, a 6 inch × 6 inch sample was fabricated demonstrating the feasibility of making large area 3D

  4. 3D Microperfusion Model of ADPKD

    DTIC Science & Technology

    2015-10-01

    Stratasys 3D printer . PDMS was cast in the negative molds in order to create permanent biocompatible plastic masters (SmoothCast 310). All goals of task...1 AWARD NUMBER: W81XWH-14-1-0304 TITLE: 3D Microperfusion Model of ADPKD PRINCIPAL INVESTIGATOR: David L. Kaplan CONTRACTING ORGANIZATION...ADDRESS. 1. REPORT DATE October 2015 2. REPORT TYPE Annual Report 3. DATES COVERED 15 Sep 2014 - 14 Sep 2015 4. TITLE AND SUBTITLE 3D

  5. 3D carotid plaque MR Imaging

    PubMed Central

    Parker, Dennis L.

    2015-01-01

    SYNOPSIS There has been significant progress made in 3D carotid plaque magnetic resonance imaging techniques in recent years. 3D plaque imaging clearly represents the future in clinical use. With effective flow suppression techniques, choices of different contrast weighting acquisitions, and time-efficient imaging approaches, 3D plaque imaging offers flexible imaging plane and view angle analysis, large coverage, multi-vascular beds capability, and even can be used in fast screening. PMID:26610656

  6. 3-D Extensions for Trustworthy Systems

    DTIC Science & Technology

    2011-01-01

    3- D Extensions for Trustworthy Systems (Invited Paper) Ted Huffmire∗, Timothy Levin∗, Cynthia Irvine∗, Ryan Kastner† and Timothy Sherwood...address these problems, we propose an approach to trustworthy system development based on 3- D integration, an emerging chip fabrication technique in...which two or more integrated circuit dies are fabricated individually and then combined into a single stack using vertical conductive posts. With 3- D

  7. Hardware Trust Implications of 3-D Integration

    DTIC Science & Technology

    2010-12-01

    enhancing a commod- ity processor with a variety of security functions. This paper examines the 3-D design approach and provides an analysis concluding...of key components. The question addressed by this paper is, “Can a 3-D control plane provide useful secure services when it is conjoined with an...untrust- worthy computation plane?” Design-level investigation of this question yields a definite yes. This paper explores 3- D applications and their

  8. Digital holography and 3-D imaging.

    PubMed

    Banerjee, Partha; Barbastathis, George; Kim, Myung; Kukhtarev, Nickolai

    2011-03-01

    This feature issue on Digital Holography and 3-D Imaging comprises 15 papers on digital holographic techniques and applications, computer-generated holography and encryption techniques, and 3-D display. It is hoped that future work in the area leads to innovative applications of digital holography and 3-D imaging to biology and sensing, and to the development of novel nonlinear dynamic digital holographic techniques.

  9. Geometry and Topology of Two-Dimensional Dry Foams: Computer Simulation and Experimental Characterization.

    PubMed

    Tong, Mingming; Cole, Katie; Brito-Parada, Pablo R; Neethling, Stephen; Cilliers, Jan J

    2017-04-05

    Pseudo-two-dimensional (2D) foams are commonly used in foam studies as it is experimentally easier to measure the bubble size distribution and other geometric and topological properties of these foams than it is for a 3D foam. Despite the widespread use of 2D foams in both simulation and experimental studies, many important geometric and topological relationships are still not well understood. Film size, for example, is a key parameter in the stability of bubbles and the overall structure of foams. The relationship between the size distribution of the films in a foam and that of the bubbles themselves is thus a key relationship in the modeling and simulation of unstable foams. This work uses structural simulation from Surface Evolver to statistically analyze this relationship and to ultimately formulate a relationship for the film size in 2D foams that is shown to be valid across a wide range of different bubble polydispersities. These results and other topological features are then validated using digital image analysis of experimental pseudo-2D foams produced in a vertical Hele-Shaw cell, which contains a monolayer of bubbles between two plates. From both the experimental and computational results, it is shown that there is a distribution of sizes that a film can adopt and that this distribution is very strongly dependent on the sizes of the two bubbles to which the film is attached, especially the smaller one, but that it is virtually independent of the underlying polydispersity of the foam.

  10. Dimensional accuracy of 3D printed vertebra

    NASA Astrophysics Data System (ADS)

    Ogden, Kent; Ordway, Nathaniel; Diallo, Dalanda; Tillapaugh-Fay, Gwen; Aslan, Can

    2014-03-01

    3D printer applications in the biomedical sciences and medical imaging are expanding and will have an increasing impact on the practice of medicine. Orthopedic and reconstructive surgery has been an obvious area for development of 3D printer applications as the segmentation of bony anatomy to generate printable models is relatively straightforward. There are important issues that should be addressed when using 3D printed models for applications that may affect patient care; in particular the dimensional accuracy of the printed parts needs to be high to avoid poor decisions being made prior to surgery or therapeutic procedures. In this work, the dimensional accuracy of 3D printed vertebral bodies derived from CT data for a cadaver spine is compared with direct measurements on the ex-vivo vertebra and with measurements made on the 3D rendered vertebra using commercial 3D image processing software. The vertebra was printed on a consumer grade 3D printer using an additive print process using PLA (polylactic acid) filament. Measurements were made for 15 different anatomic features of the vertebral body, including vertebral body height, endplate width and depth, pedicle height and width, and spinal canal width and depth, among others. It is shown that for the segmentation and printing process used, the results of measurements made on the 3D printed vertebral body are substantially the same as those produced by direct measurement on the vertebra and measurements made on the 3D rendered vertebra.

  11. High Temperature Structural Foam

    NASA Technical Reports Server (NTRS)

    Weiser, Erik S.; Baillif, Faye F.; Grimsley, Brian W.; Marchello, Joseph M.

    1997-01-01

    The Aerospace Industry is experiencing growing demand for high performance polymer foam. The X-33 program needs structural foam insulation capable of retaining its strength over a wide range of environmental conditions. The High Speed Research Program has a need for low density core splice and potting materials. This paper reviews the state of the art in foam materials and describes experimental work to fabricate low density, high shear strength foam which can withstand temperatures from -220 C to 220 C. Commercially available polymer foams exhibit a wide range of physical properties. Some with densities as low as 0.066 g/cc are capable of co-curing at temperatures as high as 182 C. Rohacell foams can be resin transfer molded at temperatures up to 180 C. They have moduli of elasticity of 0.19 MPa, tensile strengths of 3.7 Mpa and compressive strengths of 3.6 MPa. The Rohacell foams cannot withstand liquid hydrogen temperatures, however Imi-Tech markets Solimide (trademark) foams which withstand temperatures from -250 C to 200 C, but they do not have the required structural integrity. The research activity at NASA Langley Research Center focuses on using chemical blowing agents to produce polyimide thermoplastic foams capable of meeting the above performance requirements. The combination of blowing agents that decompose at the minimum melt viscosity temperature together with plasticizers to lower the viscosity has been used to produce foams by both extrusion and oven heating. The foams produced exhibit good environmental stability while maintaining structural properties.

  12. FastScript3D - A Companion to Java 3D

    NASA Technical Reports Server (NTRS)

    Koenig, Patti

    2005-01-01

    FastScript3D is a computer program, written in the Java 3D(TM) programming language, that establishes an alternative language that helps users who lack expertise in Java 3D to use Java 3D for constructing three-dimensional (3D)-appearing graphics. The FastScript3D language provides a set of simple, intuitive, one-line text-string commands for creating, controlling, and animating 3D models. The first word in a string is the name of a command; the rest of the string contains the data arguments for the command. The commands can also be used as an aid to learning Java 3D. Developers can extend the language by adding custom text-string commands. The commands can define new 3D objects or load representations of 3D objects from files in formats compatible with such other software systems as X3D. The text strings can be easily integrated into other languages. FastScript3D facilitates communication between scripting languages [which enable programming of hyper-text markup language (HTML) documents to interact with users] and Java 3D. The FastScript3D language can be extended and customized on both the scripting side and the Java 3D side.

  13. 3D ultrafast ultrasound imaging in vivo.

    PubMed

    Provost, Jean; Papadacci, Clement; Arango, Juan Esteban; Imbault, Marion; Fink, Mathias; Gennisson, Jean-Luc; Tanter, Mickael; Pernot, Mathieu

    2014-10-07

    Very high frame rate ultrasound imaging has recently allowed for the extension of the applications of echography to new fields of study such as the functional imaging of the brain, cardiac electrophysiology, and the quantitative imaging of the intrinsic mechanical properties of tumors, to name a few, non-invasively and in real time. In this study, we present the first implementation of Ultrafast Ultrasound Imaging in 3D based on the use of either diverging or plane waves emanating from a sparse virtual array located behind the probe. It achieves high contrast and resolution while maintaining imaging rates of thousands of volumes per second. A customized portable ultrasound system was developed to sample 1024 independent channels and to drive a 32  ×  32 matrix-array probe. Its ability to track in 3D transient phenomena occurring in the millisecond range within a single ultrafast acquisition was demonstrated for 3D Shear-Wave Imaging, 3D Ultrafast Doppler Imaging, and, finally, 3D Ultrafast combined Tissue and Flow Doppler Imaging. The propagation of shear waves was tracked in a phantom and used to characterize its stiffness. 3D Ultrafast Doppler was used to obtain 3D maps of Pulsed Doppler, Color Doppler, and Power Doppler quantities in a single acquisition and revealed, at thousands of volumes per second, the complex 3D flow patterns occurring in the ventricles of the human heart during an entire cardiac cycle, as well as the 3D in vivo interaction of blood flow and wall motion during the pulse wave in the carotid at the bifurcation. This study demonstrates the potential of 3D Ultrafast Ultrasound Imaging for the 3D mapping of stiffness, tissue motion, and flow in humans in vivo and promises new clinical applications of ultrasound with reduced intra--and inter-observer variability.

  14. 3D ultrafast ultrasound imaging in vivo

    NASA Astrophysics Data System (ADS)

    Provost, Jean; Papadacci, Clement; Esteban Arango, Juan; Imbault, Marion; Fink, Mathias; Gennisson, Jean-Luc; Tanter, Mickael; Pernot, Mathieu

    2014-10-01

    Very high frame rate ultrasound imaging has recently allowed for the extension of the applications of echography to new fields of study such as the functional imaging of the brain, cardiac electrophysiology, and the quantitative imaging of the intrinsic mechanical properties of tumors, to name a few, non-invasively and in real time. In this study, we present the first implementation of Ultrafast Ultrasound Imaging in 3D based on the use of either diverging or plane waves emanating from a sparse virtual array located behind the probe. It achieves high contrast and resolution while maintaining imaging rates of thousands of volumes per second. A customized portable ultrasound system was developed to sample 1024 independent channels and to drive a 32  ×  32 matrix-array probe. Its ability to track in 3D transient phenomena occurring in the millisecond range within a single ultrafast acquisition was demonstrated for 3D Shear-Wave Imaging, 3D Ultrafast Doppler Imaging, and, finally, 3D Ultrafast combined Tissue and Flow Doppler Imaging. The propagation of shear waves was tracked in a phantom and used to characterize its stiffness. 3D Ultrafast Doppler was used to obtain 3D maps of Pulsed Doppler, Color Doppler, and Power Doppler quantities in a single acquisition and revealed, at thousands of volumes per second, the complex 3D flow patterns occurring in the ventricles of the human heart during an entire cardiac cycle, as well as the 3D in vivo interaction of blood flow and wall motion during the pulse wave in the carotid at the bifurcation. This study demonstrates the potential of 3D Ultrafast Ultrasound Imaging for the 3D mapping of stiffness, tissue motion, and flow in humans in vivo and promises new clinical applications of ultrasound with reduced intra—and inter-observer variability.

  15. An aerial 3D printing test mission

    NASA Astrophysics Data System (ADS)

    Hirsch, Michael; McGuire, Thomas; Parsons, Michael; Leake, Skye; Straub, Jeremy

    2016-05-01

    This paper provides an overview of an aerial 3D printing technology, its development and its testing. This technology is potentially useful in its own right. In addition, this work advances the development of a related in-space 3D printing technology. A series of aerial 3D printing test missions, used to test the aerial printing technology, are discussed. Through completing these test missions, the design for an in-space 3D printer may be advanced. The current design for the in-space 3D printer involves focusing thermal energy to heat an extrusion head and allow for the extrusion of molten print material. Plastics can be used as well as composites including metal, allowing for the extrusion of conductive material. A variety of experiments will be used to test this initial 3D printer design. High altitude balloons will be used to test the effects of microgravity on 3D printing, as well as parabolic flight tests. Zero pressure balloons can be used to test the effect of long 3D printing missions subjected to low temperatures. Vacuum chambers will be used to test 3D printing in a vacuum environment. The results will be used to adapt a current prototype of an in-space 3D printer. Then, a small scale prototype can be sent into low-Earth orbit as a 3-U cube satellite. With the ability to 3D print in space demonstrated, future missions can launch production hardware through which the sustainability and durability of structures in space will be greatly improved.

  16. Indentation of aluminium foam at low velocity

    NASA Astrophysics Data System (ADS)

    Shi, Xiaopeng; Miao, Yinggang; Liu, Shuangyan; Li, Yulong; Lu, Guoxing

    2015-09-01

    The indentation behaviour of aluminium foams at low velocity (10 m/s ˜ 30 m/s) was investigated both in experiments and numerical simulation in this paper. A flat-ended indenter was used and the force-displacement history was recorded. The Split Hopkinson Pressure bar was used to obtain the indentation velocity and forces in the dynamic experiments. Because of the low strength of the aluminium foam, PMMA bar was used, and the experimental data were corrected using Bacon's method. The energy absorption characteristics varying with impact velocity were then obtained. It was found that the energy absorption ability of aluminium foam gradually increases in the quasi-static regime and shows a significant increase at ˜10 m/s velocity. Numerical simulation was also conducted to investigate this process. A 3D Voronoi model was used and models with different relative densities were investigated as well as those with different failure strain. The indentation energy increases with both the relative density and failure strain. The analysis of the FE model implies that the significant change in energy absorption ability of aluminium foam in indentation at ˜10 m/s velocity may be caused by plastic wave effect.

  17. Chronicles of foam films.

    PubMed

    Gochev, G; Platikanov, D; Miller, R

    2016-07-01

    The history of the scientific research on foam films, traditionally known as soap films, dates back to as early as the late 17th century when Boyle and Hooke paid special attention to the colours of soap bubbles. Their inspiration was transferred to Newton, who began systematic study of the science of foam films. Over the next centuries, a number of scientists dealt with the open questions of the drainage, stability and thickness of foam films. The significant contributions of Plateau and Gibbs in the middle/late 19th century are particularly recognized. After the "colours" method of Newton, Reinold and Rücker as well as Johhonnot developed optical methods for measuring the thickness of the thinner "non-colour" films (first order black) that are still in use today. At the beginning of the 20th century, various aspects of the foam film science were elucidated by the works of Dewar and Perrin and later by Mysels. Undoubtedly, the introduction of the disjoining pressure by Derjaguin and the manifestation of the DLVO theory in describing the film stability are considered as milestones in the theoretical development of foam films. The study of foam films gained momentum with the introduction of the microscopic foam film methodology by Scheludko and Exerowa, which is widely used today. This historical perspective serves as a guide through the chronological development of knowledge on foam films achieved over several centuries.

  18. Integration of real-time 3D image acquisition and multiview 3D display

    NASA Astrophysics Data System (ADS)

    Zhang, Zhaoxing; Geng, Zheng; Li, Tuotuo; Li, Wei; Wang, Jingyi; Liu, Yongchun

    2014-03-01

    Seamless integration of 3D acquisition and 3D display systems offers enhanced experience in 3D visualization of the real world objects or scenes. The vivid representation of captured 3D objects displayed on a glasses-free 3D display screen could bring the realistic viewing experience to viewers as if they are viewing real-world scene. Although the technologies in 3D acquisition and 3D display have advanced rapidly in recent years, effort is lacking in studying the seamless integration of these two different aspects of 3D technologies. In this paper, we describe our recent progress on integrating a light-field 3D acquisition system and an autostereoscopic multiview 3D display for real-time light field capture and display. This paper focuses on both the architecture design and the implementation of the hardware and the software of this integrated 3D system. A prototype of the integrated 3D system is built to demonstrate the real-time 3D acquisition and 3D display capability of our proposed system.

  19. Immersive 3D Geovisualization in Higher Education

    ERIC Educational Resources Information Center

    Philips, Andrea; Walz, Ariane; Bergner, Andreas; Graeff, Thomas; Heistermann, Maik; Kienzler, Sarah; Korup, Oliver; Lipp, Torsten; Schwanghart, Wolfgang; Zeilinger, Gerold

    2015-01-01

    In this study, we investigate how immersive 3D geovisualization can be used in higher education. Based on MacEachren and Kraak's geovisualization cube, we examine the usage of immersive 3D geovisualization and its usefulness in a research-based learning module on flood risk, called GEOSimulator. Results of a survey among participating students…

  20. A 3D Geostatistical Mapping Tool

    SciTech Connect

    Weiss, W. W.; Stevenson, Graig; Patel, Ketan; Wang, Jun

    1999-02-09

    This software provides accurate 3D reservoir modeling tools and high quality 3D graphics for PC platforms enabling engineers and geologists to better comprehend reservoirs and consequently improve their decisions. The mapping algorithms are fractals, kriging, sequential guassian simulation, and three nearest neighbor methods.

  1. 3D Printing. What's the Harm?

    ERIC Educational Resources Information Center

    Love, Tyler S.; Roy, Ken

    2016-01-01

    Health concerns from 3D printing were first documented by Stephens, Azimi, Orch, and Ramos (2013), who found that commercially available 3D printers were producing hazardous levels of ultrafine particles (UFPs) and volatile organic compounds (VOCs) when plastic materials were melted through the extruder. UFPs are particles less than 100 nanometers…

  2. Topology dictionary for 3D video understanding.

    PubMed

    Tung, Tony; Matsuyama, Takashi

    2012-08-01

    This paper presents a novel approach that achieves 3D video understanding. 3D video consists of a stream of 3D models of subjects in motion. The acquisition of long sequences requires large storage space (2 GB for 1 min). Moreover, it is tedious to browse data sets and extract meaningful information. We propose the topology dictionary to encode and describe 3D video content. The model consists of a topology-based shape descriptor dictionary which can be generated from either extracted patterns or training sequences. The model relies on 1) topology description and classification using Reeb graphs, and 2) a Markov motion graph to represent topology change states. We show that the use of Reeb graphs as the high-level topology descriptor is relevant. It allows the dictionary to automatically model complex sequences, whereas other strategies would require prior knowledge on the shape and topology of the captured subjects. Our approach serves to encode 3D video sequences, and can be applied for content-based description and summarization of 3D video sequences. Furthermore, topology class labeling during a learning process enables the system to perform content-based event recognition. Experiments were carried out on various 3D videos. We showcase an application for 3D video progressive summarization using the topology dictionary.

  3. 3D elastic control for mobile devices.

    PubMed

    Hachet, Martin; Pouderoux, Joachim; Guitton, Pascal

    2008-01-01

    To increase the input space of mobile devices, the authors developed a proof-of-concept 3D elastic controller that easily adapts to mobile devices. This embedded device improves the completion of high-level interaction tasks such as visualization of large documents and navigation in 3D environments. It also opens new directions for tomorrow's mobile applications.

  4. 3D Printing of Molecular Models

    ERIC Educational Resources Information Center

    Gardner, Adam; Olson, Arthur

    2016-01-01

    Physical molecular models have played a valuable role in our understanding of the invisible nano-scale world. We discuss 3D printing and its use in producing models of the molecules of life. Complex biomolecular models, produced from 3D printed parts, can demonstrate characteristics of molecular structure and function, such as viral self-assembly,…

  5. 3D Printed Block Copolymer Nanostructures

    ERIC Educational Resources Information Center

    Scalfani, Vincent F.; Turner, C. Heath; Rupar, Paul A.; Jenkins, Alexander H.; Bara, Jason E.

    2015-01-01

    The emergence of 3D printing has dramatically advanced the availability of tangible molecular and extended solid models. Interestingly, there are few nanostructure models available both commercially and through other do-it-yourself approaches such as 3D printing. This is unfortunate given the importance of nanotechnology in science today. In this…

  6. Infrastructure for 3D Imaging Test Bed

    DTIC Science & Technology

    2007-05-11

    analysis. (c.) Real time detection & analysis of human gait: using a video camera we capture walking human silhouette for pattern modeling and gait ... analysis . Fig. 5 shows the scanning result result that is fed into a Geo-magic software tool for 3D meshing. Fig. 5: 3D scanning result In

  7. Wow! 3D Content Awakens the Classroom

    ERIC Educational Resources Information Center

    Gordon, Dan

    2010-01-01

    From her first encounter with stereoscopic 3D technology designed for classroom instruction, Megan Timme, principal at Hamilton Park Pacesetter Magnet School in Dallas, sensed it could be transformative. Last spring, when she began pilot-testing 3D content in her third-, fourth- and fifth-grade classrooms, Timme wasn't disappointed. Students…

  8. Stereo 3-D Vision in Teaching Physics

    ERIC Educational Resources Information Center

    Zabunov, Svetoslav

    2012-01-01

    Stereo 3-D vision is a technology used to present images on a flat surface (screen, paper, etc.) and at the same time to create the notion of three-dimensional spatial perception of the viewed scene. A great number of physical processes are much better understood when viewed in stereo 3-D vision compared to standard flat 2-D presentation. The…

  9. Pathways for Learning from 3D Technology

    ERIC Educational Resources Information Center

    Carrier, L. Mark; Rab, Saira S.; Rosen, Larry D.; Vasquez, Ludivina; Cheever, Nancy A.

    2012-01-01

    The purpose of this study was to find out if 3D stereoscopic presentation of information in a movie format changes a viewer's experience of the movie content. Four possible pathways from 3D presentation to memory and learning were considered: a direct connection based on cognitive neuroscience research; a connection through "immersion"…

  10. 3D, or Not to Be?

    ERIC Educational Resources Information Center

    Norbury, Keith

    2012-01-01

    It may be too soon for students to be showing up for class with popcorn and gummy bears, but technology similar to that behind the 3D blockbuster movie "Avatar" is slowly finding its way into college classrooms. 3D classroom projectors are taking students on fantastic voyages inside the human body, to the ruins of ancient Greece--even to faraway…

  11. Static & Dynamic Response of 3D Solids

    SciTech Connect

    Lin, Jerry

    1996-07-15

    NIKE3D is a large deformations 3D finite element code used to obtain the resulting displacements and stresses from multi-body static and dynamic structural thermo-mechanics problems with sliding interfaces. Many nonlinear and temperature dependent constitutive models are available.

  12. BEAMS3D Neutral Beam Injection Model

    SciTech Connect

    Lazerson, Samuel

    2014-04-14

    With the advent of applied 3D fi elds in Tokamaks and modern high performance stellarators, a need has arisen to address non-axisymmetric effects on neutral beam heating and fueling. We report on the development of a fully 3D neutral beam injection (NBI) model, BEAMS3D, which addresses this need by coupling 3D equilibria to a guiding center code capable of modeling neutral and charged particle trajectories across the separatrix and into the plasma core. Ionization, neutralization, charge-exchange, viscous velocity reduction, and pitch angle scattering are modeled with the ADAS atomic physics database [1]. Benchmark calculations are presented to validate the collisionless particle orbits, neutral beam injection model, frictional drag, and pitch angle scattering effects. A calculation of neutral beam heating in the NCSX device is performed, highlighting the capability of the code to handle 3D magnetic fields.

  13. Fabrication of 3D Silicon Sensors

    SciTech Connect

    Kok, A.; Hansen, T.E.; Hansen, T.A.; Lietaer, N.; Summanwar, A.; Kenney, C.; Hasi, J.; Da Via, C.; Parker, S.I.; /Hawaii U.

    2012-06-06

    Silicon sensors with a three-dimensional (3-D) architecture, in which the n and p electrodes penetrate through the entire substrate, have many advantages over planar silicon sensors including radiation hardness, fast time response, active edge and dual readout capabilities. The fabrication of 3D sensors is however rather complex. In recent years, there have been worldwide activities on 3D fabrication. SINTEF in collaboration with Stanford Nanofabrication Facility have successfully fabricated the original (single sided double column type) 3D detectors in two prototype runs and the third run is now on-going. This paper reports the status of this fabrication work and the resulted yield. The work of other groups such as the development of double sided 3D detectors is also briefly reported.

  14. 2D/3D switchable displays

    NASA Astrophysics Data System (ADS)

    Dekker, T.; de Zwart, S. T.; Willemsen, O. H.; Hiddink, M. G. H.; IJzerman, W. L.

    2006-02-01

    A prerequisite for a wide market acceptance of 3D displays is the ability to switch between 3D and full resolution 2D. In this paper we present a robust and cost effective concept for an auto-stereoscopic switchable 2D/3D display. The display is based on an LCD panel, equipped with switchable LC-filled lenticular lenses. We will discuss 3D image quality, with the focus on display uniformity. We show that slanting the lenticulars in combination with a good lens design can minimize non-uniformities in our 20" 2D/3D monitors. Furthermore, we introduce fractional viewing systems as a very robust concept to further improve uniformity in the case slanting the lenticulars and optimizing the lens design are not sufficient. We will discuss measurements and numerical simulations of the key optical characteristics of this display. Finally, we discuss 2D image quality, the switching characteristics and the residual lens effect.

  15. 6D Interpretation of 3D Gravity

    NASA Astrophysics Data System (ADS)

    Herfray, Yannick; Krasnov, Kirill; Scarinci, Carlos

    2017-02-01

    We show that 3D gravity, in its pure connection formulation, admits a natural 6D interpretation. The 3D field equations for the connection are equivalent to 6D Hitchin equations for the Chern–Simons 3-form in the total space of the principal bundle over the 3-dimensional base. Turning this construction around one gets an explanation of why the pure connection formulation of 3D gravity exists. More generally, we interpret 3D gravity as the dimensional reduction of the 6D Hitchin theory. To this end, we show that any \\text{SU}(2) invariant closed 3-form in the total space of the principal \\text{SU}(2) bundle can be parametrised by a connection together with a 2-form field on the base. The dimensional reduction of the 6D Hitchin theory then gives rise to 3D gravity coupled to a topological 2-form field.

  16. Biocompatible 3D Matrix with Antimicrobial Properties.

    PubMed

    Ion, Alberto; Andronescu, Ecaterina; Rădulescu, Dragoș; Rădulescu, Marius; Iordache, Florin; Vasile, Bogdan Ștefan; Surdu, Adrian Vasile; Albu, Madalina Georgiana; Maniu, Horia; Chifiriuc, Mariana Carmen; Grumezescu, Alexandru Mihai; Holban, Alina Maria

    2016-01-20

    The aim of this study was to develop, characterize and assess the biological activity of a new regenerative 3D matrix with antimicrobial properties, based on collagen (COLL), hydroxyapatite (HAp), β-cyclodextrin (β-CD) and usnic acid (UA). The prepared 3D matrix was characterized by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Microscopy (FT-IRM), Transmission Electron Microscopy (TEM), and X-ray Diffraction (XRD). In vitro qualitative and quantitative analyses performed on cultured diploid cells demonstrated that the 3D matrix is biocompatible, allowing the normal development and growth of MG-63 osteoblast-like cells and exhibited an antimicrobial effect, especially on the Staphylococcus aureus strain, explained by the particular higher inhibitory activity of usnic acid (UA) against Gram positive bacterial strains. Our data strongly recommend the obtained 3D matrix to be used as a successful alternative for the fabrication of three dimensional (3D) anti-infective regeneration matrix for bone tissue engineering.

  17. Quon 3D language for quantum information

    PubMed Central

    Liu, Zhengwei; Wozniakowski, Alex; Jaffe, Arthur M.

    2017-01-01

    We present a 3D topological picture-language for quantum information. Our approach combines charged excitations carried by strings, with topological properties that arise from embedding the strings in the interior of a 3D manifold with boundary. A quon is a composite that acts as a particle. Specifically, a quon is a hemisphere containing a neutral pair of open strings with opposite charge. We interpret multiquons and their transformations in a natural way. We obtain a type of relation, a string–genus “joint relation,” involving both a string and the 3D manifold. We use the joint relation to obtain a topological interpretation of the C∗-Hopf algebra relations, which are widely used in tensor networks. We obtain a 3D representation of the controlled NOT (CNOT) gate that is considerably simpler than earlier work, and a 3D topological protocol for teleportation. PMID:28167790

  18. Conductive polymer nanocomposites with hierarchical multi-scale structures via self-assembly of carbon-nanotubes on graphene on polymer-microspheres.

    PubMed

    Tang, Changyu; Long, Gucheng; Hu, Xin; Wong, Ka-wai; Lau, Woon-ming; Fan, Meikun; Mei, Jun; Xu, Tao; Wang, Bin; Hui, David

    2014-07-21

    A novel and highly conductive 3-dimensional (3D) hierarchical multi-scale structure is formed by a new, simple, facile, and water-based method that enables practical production of conductive carbon nanofiller/polymer composites. More specifically, the π-π interaction between CNTs and graphene oxide (GO) is exploited to disperse conductive but non-polar CNTs with amphiphilic GO sheets to form a stable aqueous colloidal solution. Aqueous-dispersible latex-polystyrene microspheres are then added to enable the self-assembly processes of anchoring CNTs on GO and wrapping microspheres with GO-stabilized CNTs for the formation of an intriguing 3D hierarchical multi-scale structure. During this process, GO is reduced to conductive reduced-graphene oxide (RGO). The resultant RGO sheets act as "nano-walls" to prevent CNTs from randomly diffusing into the polymer bulk during thermal pressing of RGO-CNT/microspheres, which results in the formation of a 3D foam-like network of RGO-CNTs with high quality. The resultant composite with such a structure gives an ultra-low percolation threshold (0.03 vol% RGO-CNTs) and a reasonably high conductivity (153 S m(-1) at 4 vol% RGO-CNTs), which could satisfy various applications requiring both transparency and electrical conduction characteristics (e.g. transparent antistatic coatings, capacitive touch-screens, and transparent electronic devices).

  19. 3D Ultrafast Ultrasound Imaging In Vivo

    PubMed Central

    Provost, Jean; Papadacci, Clement; Arango, Juan Esteban; Imbault, Marion; Gennisson, Jean-Luc; Tanter, Mickael; Pernot, Mathieu

    2014-01-01

    Very high frame rate ultrasound imaging has recently allowed for the extension of the applications of echography to new fields of study such as the functional imaging of the brain, cardiac electrophysiology, and the quantitative real-time imaging of the intrinsic mechanical properties of tumors, to name a few, non-invasively and in real time. In this study, we present the first implementation of Ultrafast Ultrasound Imaging in three dimensions based on the use of either diverging or plane waves emanating from a sparse virtual array located behind the probe. It achieves high contrast and resolution while maintaining imaging rates of thousands of volumes per second. A customized portable ultrasound system was developed to sample 1024 independent channels and to drive a 32×32 matrix-array probe. Its capability to track in 3D transient phenomena occurring in the millisecond range within a single ultrafast acquisition was demonstrated for 3-D Shear-Wave Imaging, 3-D Ultrafast Doppler Imaging and finally 3D Ultrafast combined Tissue and Flow Doppler. The propagation of shear waves was tracked in a phantom and used to characterize its stiffness. 3-D Ultrafast Doppler was used to obtain 3-D maps of Pulsed Doppler, Color Doppler, and Power Doppler quantities in a single acquisition and revealed, for the first time, the complex 3-D flow patterns occurring in the ventricles of the human heart during an entire cardiac cycle, and the 3-D in vivo interaction of blood flow and wall motion during the pulse wave in the carotid at the bifurcation. This study demonstrates the potential of 3-D Ultrafast Ultrasound Imaging for the 3-D real-time mapping of stiffness, tissue motion, and flow in humans in vivo and promises new clinical applications of ultrasound with reduced intra- and inter-observer variability. PMID:25207828

  20. 3D Visualization Development of SIUE Campus

    NASA Astrophysics Data System (ADS)

    Nellutla, Shravya

    Geographic Information Systems (GIS) has progressed from the traditional map-making to the modern technology where the information can be created, edited, managed and analyzed. Like any other models, maps are simplified representations of real world. Hence visualization plays an essential role in the applications of GIS. The use of sophisticated visualization tools and methods, especially three dimensional (3D) modeling, has been rising considerably due to the advancement of technology. There are currently many off-the-shelf technologies available in the market to build 3D GIS models. One of the objectives of this research was to examine the available ArcGIS and its extensions for 3D modeling and visualization and use them to depict a real world scenario. Furthermore, with the advent of the web, a platform for accessing and sharing spatial information on the Internet, it is possible to generate interactive online maps. Integrating Internet capacity with GIS functionality redefines the process of sharing and processing the spatial information. Enabling a 3D map online requires off-the-shelf GIS software, 3D model builders, web server, web applications and client server technologies. Such environments are either complicated or expensive because of the amount of hardware and software involved. Therefore, the second objective of this research was to investigate and develop simpler yet cost-effective 3D modeling approach that uses available ArcGIS suite products and the free 3D computer graphics software for designing 3D world scenes. Both ArcGIS Explorer and ArcGIS Online will be used to demonstrate the way of sharing and distributing 3D geographic information on the Internet. A case study of the development of 3D campus for the Southern Illinois University Edwardsville is demonstrated.